1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 *  linux/fs/ext4/inode.c
   4 *
   5 * Copyright (C) 1992, 1993, 1994, 1995
   6 * Remy Card (card@masi.ibp.fr)
   7 * Laboratoire MASI - Institut Blaise Pascal
   8 * Universite Pierre et Marie Curie (Paris VI)
   9 *
  10 *  from
  11 *
  12 *  linux/fs/minix/inode.c
  13 *
  14 *  Copyright (C) 1991, 1992  Linus Torvalds
  15 *
  16 *  64-bit file support on 64-bit platforms by Jakub Jelinek
  17 *	(jj@sunsite.ms.mff.cuni.cz)
  18 *
  19 *  Assorted race fixes, rewrite of ext4_get_block() by Al Viro, 2000
  20 */
  21
  22#include <linux/fs.h>
 
  23#include <linux/time.h>
  24#include <linux/highuid.h>
  25#include <linux/pagemap.h>
  26#include <linux/dax.h>
  27#include <linux/quotaops.h>
  28#include <linux/string.h>
  29#include <linux/buffer_head.h>
  30#include <linux/writeback.h>
  31#include <linux/pagevec.h>
  32#include <linux/mpage.h>
  33#include <linux/namei.h>
  34#include <linux/uio.h>
  35#include <linux/bio.h>
  36#include <linux/workqueue.h>
  37#include <linux/kernel.h>
  38#include <linux/printk.h>
  39#include <linux/slab.h>
  40#include <linux/bitops.h>
  41#include <linux/iomap.h>
  42#include <linux/iversion.h>
  43
  44#include "ext4_jbd2.h"
  45#include "xattr.h"
  46#include "acl.h"
  47#include "truncate.h"
  48
  49#include <trace/events/ext4.h>
  50
  51#define MPAGE_DA_EXTENT_TAIL 0x01
  52
  53static __u32 ext4_inode_csum(struct inode *inode, struct ext4_inode *raw,
  54			      struct ext4_inode_info *ei)
  55{
  56	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
  57	__u32 csum;
  58	__u16 dummy_csum = 0;
  59	int offset = offsetof(struct ext4_inode, i_checksum_lo);
  60	unsigned int csum_size = sizeof(dummy_csum);
  61
  62	csum = ext4_chksum(sbi, ei->i_csum_seed, (__u8 *)raw, offset);
  63	csum = ext4_chksum(sbi, csum, (__u8 *)&dummy_csum, csum_size);
  64	offset += csum_size;
  65	csum = ext4_chksum(sbi, csum, (__u8 *)raw + offset,
  66			   EXT4_GOOD_OLD_INODE_SIZE - offset);
  67
  68	if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE) {
  69		offset = offsetof(struct ext4_inode, i_checksum_hi);
  70		csum = ext4_chksum(sbi, csum, (__u8 *)raw +
  71				   EXT4_GOOD_OLD_INODE_SIZE,
  72				   offset - EXT4_GOOD_OLD_INODE_SIZE);
  73		if (EXT4_FITS_IN_INODE(raw, ei, i_checksum_hi)) {
  74			csum = ext4_chksum(sbi, csum, (__u8 *)&dummy_csum,
  75					   csum_size);
  76			offset += csum_size;
  77		}
  78		csum = ext4_chksum(sbi, csum, (__u8 *)raw + offset,
  79				   EXT4_INODE_SIZE(inode->i_sb) - offset);
  80	}
  81
  82	return csum;
  83}
  84
  85static int ext4_inode_csum_verify(struct inode *inode, struct ext4_inode *raw,
  86				  struct ext4_inode_info *ei)
  87{
  88	__u32 provided, calculated;
  89
  90	if (EXT4_SB(inode->i_sb)->s_es->s_creator_os !=
  91	    cpu_to_le32(EXT4_OS_LINUX) ||
  92	    !ext4_has_metadata_csum(inode->i_sb))
  93		return 1;
  94
  95	provided = le16_to_cpu(raw->i_checksum_lo);
  96	calculated = ext4_inode_csum(inode, raw, ei);
  97	if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE &&
  98	    EXT4_FITS_IN_INODE(raw, ei, i_checksum_hi))
  99		provided |= ((__u32)le16_to_cpu(raw->i_checksum_hi)) << 16;
 100	else
 101		calculated &= 0xFFFF;
 102
 103	return provided == calculated;
 104}
 105
 106static void ext4_inode_csum_set(struct inode *inode, struct ext4_inode *raw,
 107				struct ext4_inode_info *ei)
 108{
 109	__u32 csum;
 110
 111	if (EXT4_SB(inode->i_sb)->s_es->s_creator_os !=
 112	    cpu_to_le32(EXT4_OS_LINUX) ||
 113	    !ext4_has_metadata_csum(inode->i_sb))
 114		return;
 115
 116	csum = ext4_inode_csum(inode, raw, ei);
 117	raw->i_checksum_lo = cpu_to_le16(csum & 0xFFFF);
 118	if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE &&
 119	    EXT4_FITS_IN_INODE(raw, ei, i_checksum_hi))
 120		raw->i_checksum_hi = cpu_to_le16(csum >> 16);
 121}
 122
 123static inline int ext4_begin_ordered_truncate(struct inode *inode,
 124					      loff_t new_size)
 125{
 126	trace_ext4_begin_ordered_truncate(inode, new_size);
 127	/*
 128	 * If jinode is zero, then we never opened the file for
 129	 * writing, so there's no need to call
 130	 * jbd2_journal_begin_ordered_truncate() since there's no
 131	 * outstanding writes we need to flush.
 132	 */
 133	if (!EXT4_I(inode)->jinode)
 134		return 0;
 135	return jbd2_journal_begin_ordered_truncate(EXT4_JOURNAL(inode),
 136						   EXT4_I(inode)->jinode,
 137						   new_size);
 138}
 139
 140static void ext4_invalidatepage(struct page *page, unsigned int offset,
 141				unsigned int length);
 142static int __ext4_journalled_writepage(struct page *page, unsigned int len);
 143static int ext4_bh_delay_or_unwritten(handle_t *handle, struct buffer_head *bh);
 144static int ext4_meta_trans_blocks(struct inode *inode, int lblocks,
 145				  int pextents);
 146
 147/*
 148 * Test whether an inode is a fast symlink.
 149 * A fast symlink has its symlink data stored in ext4_inode_info->i_data.
 150 */
 151int ext4_inode_is_fast_symlink(struct inode *inode)
 152{
 153	if (!(EXT4_I(inode)->i_flags & EXT4_EA_INODE_FL)) {
 154		int ea_blocks = EXT4_I(inode)->i_file_acl ?
 155				EXT4_CLUSTER_SIZE(inode->i_sb) >> 9 : 0;
 156
 157		if (ext4_has_inline_data(inode))
 158			return 0;
 159
 160		return (S_ISLNK(inode->i_mode) && inode->i_blocks - ea_blocks == 0);
 161	}
 162	return S_ISLNK(inode->i_mode) && inode->i_size &&
 163	       (inode->i_size < EXT4_N_BLOCKS * 4);
 164}
 165
 166/*
 167 * Restart the transaction associated with *handle.  This does a commit,
 168 * so before we call here everything must be consistently dirtied against
 169 * this transaction.
 170 */
 171int ext4_truncate_restart_trans(handle_t *handle, struct inode *inode,
 172				 int nblocks)
 173{
 174	int ret;
 175
 176	/*
 177	 * Drop i_data_sem to avoid deadlock with ext4_map_blocks.  At this
 178	 * moment, get_block can be called only for blocks inside i_size since
 179	 * page cache has been already dropped and writes are blocked by
 180	 * i_mutex. So we can safely drop the i_data_sem here.
 181	 */
 182	BUG_ON(EXT4_JOURNAL(inode) == NULL);
 183	jbd_debug(2, "restarting handle %p\n", handle);
 184	up_write(&EXT4_I(inode)->i_data_sem);
 185	ret = ext4_journal_restart(handle, nblocks);
 186	down_write(&EXT4_I(inode)->i_data_sem);
 187	ext4_discard_preallocations(inode);
 188
 189	return ret;
 190}
 191
 192/*
 193 * Called at the last iput() if i_nlink is zero.
 194 */
 195void ext4_evict_inode(struct inode *inode)
 196{
 197	handle_t *handle;
 198	int err;
 199	int extra_credits = 3;
 
 
 
 
 
 200	struct ext4_xattr_inode_array *ea_inode_array = NULL;
 
 201
 202	trace_ext4_evict_inode(inode);
 203
 204	if (inode->i_nlink) {
 205		/*
 206		 * When journalling data dirty buffers are tracked only in the
 207		 * journal. So although mm thinks everything is clean and
 208		 * ready for reaping the inode might still have some pages to
 209		 * write in the running transaction or waiting to be
 210		 * checkpointed. Thus calling jbd2_journal_invalidatepage()
 211		 * (via truncate_inode_pages()) to discard these buffers can
 212		 * cause data loss. Also even if we did not discard these
 213		 * buffers, we would have no way to find them after the inode
 214		 * is reaped and thus user could see stale data if he tries to
 215		 * read them before the transaction is checkpointed. So be
 216		 * careful and force everything to disk here... We use
 217		 * ei->i_datasync_tid to store the newest transaction
 218		 * containing inode's data.
 219		 *
 220		 * Note that directories do not have this problem because they
 221		 * don't use page cache.
 222		 */
 223		if (inode->i_ino != EXT4_JOURNAL_INO &&
 224		    ext4_should_journal_data(inode) &&
 225		    (S_ISLNK(inode->i_mode) || S_ISREG(inode->i_mode)) &&
 226		    inode->i_data.nrpages) {
 227			journal_t *journal = EXT4_SB(inode->i_sb)->s_journal;
 228			tid_t commit_tid = EXT4_I(inode)->i_datasync_tid;
 229
 230			jbd2_complete_transaction(journal, commit_tid);
 231			filemap_write_and_wait(&inode->i_data);
 232		}
 233		truncate_inode_pages_final(&inode->i_data);
 234
 235		goto no_delete;
 236	}
 237
 238	if (is_bad_inode(inode))
 239		goto no_delete;
 240	dquot_initialize(inode);
 241
 242	if (ext4_should_order_data(inode))
 243		ext4_begin_ordered_truncate(inode, 0);
 244	truncate_inode_pages_final(&inode->i_data);
 245
 246	/*
 
 
 
 
 
 
 
 
 
 
 247	 * Protect us against freezing - iput() caller didn't have to have any
 248	 * protection against it
 249	 */
 250	sb_start_intwrite(inode->i_sb);
 
 
 
 
 
 251
 252	if (!IS_NOQUOTA(inode))
 253		extra_credits += EXT4_MAXQUOTAS_DEL_BLOCKS(inode->i_sb);
 254
 
 
 
 
 255	handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE,
 256				 ext4_blocks_for_truncate(inode)+extra_credits);
 257	if (IS_ERR(handle)) {
 258		ext4_std_error(inode->i_sb, PTR_ERR(handle));
 259		/*
 260		 * If we're going to skip the normal cleanup, we still need to
 261		 * make sure that the in-core orphan linked list is properly
 262		 * cleaned up.
 263		 */
 264		ext4_orphan_del(NULL, inode);
 265		sb_end_intwrite(inode->i_sb);
 
 266		goto no_delete;
 267	}
 268
 269	if (IS_SYNC(inode))
 270		ext4_handle_sync(handle);
 271
 272	/*
 273	 * Set inode->i_size to 0 before calling ext4_truncate(). We need
 274	 * special handling of symlinks here because i_size is used to
 275	 * determine whether ext4_inode_info->i_data contains symlink data or
 276	 * block mappings. Setting i_size to 0 will remove its fast symlink
 277	 * status. Erase i_data so that it becomes a valid empty block map.
 278	 */
 279	if (ext4_inode_is_fast_symlink(inode))
 280		memset(EXT4_I(inode)->i_data, 0, sizeof(EXT4_I(inode)->i_data));
 281	inode->i_size = 0;
 282	err = ext4_mark_inode_dirty(handle, inode);
 283	if (err) {
 284		ext4_warning(inode->i_sb,
 285			     "couldn't mark inode dirty (err %d)", err);
 286		goto stop_handle;
 287	}
 288	if (inode->i_blocks) {
 289		err = ext4_truncate(inode);
 290		if (err) {
 291			ext4_error(inode->i_sb,
 292				   "couldn't truncate inode %lu (err %d)",
 293				   inode->i_ino, err);
 294			goto stop_handle;
 295		}
 296	}
 297
 298	/* Remove xattr references. */
 299	err = ext4_xattr_delete_inode(handle, inode, &ea_inode_array,
 300				      extra_credits);
 301	if (err) {
 302		ext4_warning(inode->i_sb, "xattr delete (err %d)", err);
 303stop_handle:
 304		ext4_journal_stop(handle);
 305		ext4_orphan_del(NULL, inode);
 306		sb_end_intwrite(inode->i_sb);
 
 307		ext4_xattr_inode_array_free(ea_inode_array);
 308		goto no_delete;
 309	}
 310
 311	/*
 312	 * Kill off the orphan record which ext4_truncate created.
 313	 * AKPM: I think this can be inside the above `if'.
 314	 * Note that ext4_orphan_del() has to be able to cope with the
 315	 * deletion of a non-existent orphan - this is because we don't
 316	 * know if ext4_truncate() actually created an orphan record.
 317	 * (Well, we could do this if we need to, but heck - it works)
 318	 */
 319	ext4_orphan_del(handle, inode);
 320	EXT4_I(inode)->i_dtime	= get_seconds();
 321
 322	/*
 323	 * One subtle ordering requirement: if anything has gone wrong
 324	 * (transaction abort, IO errors, whatever), then we can still
 325	 * do these next steps (the fs will already have been marked as
 326	 * having errors), but we can't free the inode if the mark_dirty
 327	 * fails.
 328	 */
 329	if (ext4_mark_inode_dirty(handle, inode))
 330		/* If that failed, just do the required in-core inode clear. */
 331		ext4_clear_inode(inode);
 332	else
 333		ext4_free_inode(handle, inode);
 334	ext4_journal_stop(handle);
 335	sb_end_intwrite(inode->i_sb);
 
 336	ext4_xattr_inode_array_free(ea_inode_array);
 337	return;
 338no_delete:
 
 
 339	ext4_clear_inode(inode);	/* We must guarantee clearing of inode... */
 340}
 341
 342#ifdef CONFIG_QUOTA
 343qsize_t *ext4_get_reserved_space(struct inode *inode)
 344{
 345	return &EXT4_I(inode)->i_reserved_quota;
 346}
 347#endif
 348
 349/*
 350 * Called with i_data_sem down, which is important since we can call
 351 * ext4_discard_preallocations() from here.
 352 */
 353void ext4_da_update_reserve_space(struct inode *inode,
 354					int used, int quota_claim)
 355{
 356	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
 357	struct ext4_inode_info *ei = EXT4_I(inode);
 358
 359	spin_lock(&ei->i_block_reservation_lock);
 360	trace_ext4_da_update_reserve_space(inode, used, quota_claim);
 361	if (unlikely(used > ei->i_reserved_data_blocks)) {
 362		ext4_warning(inode->i_sb, "%s: ino %lu, used %d "
 363			 "with only %d reserved data blocks",
 364			 __func__, inode->i_ino, used,
 365			 ei->i_reserved_data_blocks);
 366		WARN_ON(1);
 367		used = ei->i_reserved_data_blocks;
 368	}
 369
 370	/* Update per-inode reservations */
 371	ei->i_reserved_data_blocks -= used;
 372	percpu_counter_sub(&sbi->s_dirtyclusters_counter, used);
 373
 374	spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
 375
 376	/* Update quota subsystem for data blocks */
 377	if (quota_claim)
 378		dquot_claim_block(inode, EXT4_C2B(sbi, used));
 379	else {
 380		/*
 381		 * We did fallocate with an offset that is already delayed
 382		 * allocated. So on delayed allocated writeback we should
 383		 * not re-claim the quota for fallocated blocks.
 384		 */
 385		dquot_release_reservation_block(inode, EXT4_C2B(sbi, used));
 386	}
 387
 388	/*
 389	 * If we have done all the pending block allocations and if
 390	 * there aren't any writers on the inode, we can discard the
 391	 * inode's preallocations.
 392	 */
 393	if ((ei->i_reserved_data_blocks == 0) &&
 394	    (atomic_read(&inode->i_writecount) == 0))
 395		ext4_discard_preallocations(inode);
 396}
 397
 398static int __check_block_validity(struct inode *inode, const char *func,
 399				unsigned int line,
 400				struct ext4_map_blocks *map)
 401{
 402	if (!ext4_data_block_valid(EXT4_SB(inode->i_sb), map->m_pblk,
 403				   map->m_len)) {
 
 
 
 404		ext4_error_inode(inode, func, line, map->m_pblk,
 405				 "lblock %lu mapped to illegal pblock "
 406				 "(length %d)", (unsigned long) map->m_lblk,
 407				 map->m_len);
 408		return -EFSCORRUPTED;
 409	}
 410	return 0;
 411}
 412
 413int ext4_issue_zeroout(struct inode *inode, ext4_lblk_t lblk, ext4_fsblk_t pblk,
 414		       ext4_lblk_t len)
 415{
 416	int ret;
 417
 418	if (ext4_encrypted_inode(inode))
 419		return fscrypt_zeroout_range(inode, lblk, pblk, len);
 420
 421	ret = sb_issue_zeroout(inode->i_sb, pblk, len, GFP_NOFS);
 422	if (ret > 0)
 423		ret = 0;
 424
 425	return ret;
 426}
 427
 428#define check_block_validity(inode, map)	\
 429	__check_block_validity((inode), __func__, __LINE__, (map))
 430
 431#ifdef ES_AGGRESSIVE_TEST
 432static void ext4_map_blocks_es_recheck(handle_t *handle,
 433				       struct inode *inode,
 434				       struct ext4_map_blocks *es_map,
 435				       struct ext4_map_blocks *map,
 436				       int flags)
 437{
 438	int retval;
 439
 440	map->m_flags = 0;
 441	/*
 442	 * There is a race window that the result is not the same.
 443	 * e.g. xfstests #223 when dioread_nolock enables.  The reason
 444	 * is that we lookup a block mapping in extent status tree with
 445	 * out taking i_data_sem.  So at the time the unwritten extent
 446	 * could be converted.
 447	 */
 448	down_read(&EXT4_I(inode)->i_data_sem);
 449	if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) {
 450		retval = ext4_ext_map_blocks(handle, inode, map, flags &
 451					     EXT4_GET_BLOCKS_KEEP_SIZE);
 452	} else {
 453		retval = ext4_ind_map_blocks(handle, inode, map, flags &
 454					     EXT4_GET_BLOCKS_KEEP_SIZE);
 455	}
 456	up_read((&EXT4_I(inode)->i_data_sem));
 457
 458	/*
 459	 * We don't check m_len because extent will be collpased in status
 460	 * tree.  So the m_len might not equal.
 461	 */
 462	if (es_map->m_lblk != map->m_lblk ||
 463	    es_map->m_flags != map->m_flags ||
 464	    es_map->m_pblk != map->m_pblk) {
 465		printk("ES cache assertion failed for inode: %lu "
 466		       "es_cached ex [%d/%d/%llu/%x] != "
 467		       "found ex [%d/%d/%llu/%x] retval %d flags %x\n",
 468		       inode->i_ino, es_map->m_lblk, es_map->m_len,
 469		       es_map->m_pblk, es_map->m_flags, map->m_lblk,
 470		       map->m_len, map->m_pblk, map->m_flags,
 471		       retval, flags);
 472	}
 473}
 474#endif /* ES_AGGRESSIVE_TEST */
 475
 476/*
 477 * The ext4_map_blocks() function tries to look up the requested blocks,
 478 * and returns if the blocks are already mapped.
 479 *
 480 * Otherwise it takes the write lock of the i_data_sem and allocate blocks
 481 * and store the allocated blocks in the result buffer head and mark it
 482 * mapped.
 483 *
 484 * If file type is extents based, it will call ext4_ext_map_blocks(),
 485 * Otherwise, call with ext4_ind_map_blocks() to handle indirect mapping
 486 * based files
 487 *
 488 * On success, it returns the number of blocks being mapped or allocated.  if
 489 * create==0 and the blocks are pre-allocated and unwritten, the resulting @map
 490 * is marked as unwritten. If the create == 1, it will mark @map as mapped.
 491 *
 492 * It returns 0 if plain look up failed (blocks have not been allocated), in
 493 * that case, @map is returned as unmapped but we still do fill map->m_len to
 494 * indicate the length of a hole starting at map->m_lblk.
 495 *
 496 * It returns the error in case of allocation failure.
 497 */
 498int ext4_map_blocks(handle_t *handle, struct inode *inode,
 499		    struct ext4_map_blocks *map, int flags)
 500{
 501	struct extent_status es;
 502	int retval;
 503	int ret = 0;
 504#ifdef ES_AGGRESSIVE_TEST
 505	struct ext4_map_blocks orig_map;
 506
 507	memcpy(&orig_map, map, sizeof(*map));
 508#endif
 509
 510	map->m_flags = 0;
 511	ext_debug("ext4_map_blocks(): inode %lu, flag %d, max_blocks %u,"
 512		  "logical block %lu\n", inode->i_ino, flags, map->m_len,
 513		  (unsigned long) map->m_lblk);
 514
 515	/*
 516	 * ext4_map_blocks returns an int, and m_len is an unsigned int
 517	 */
 518	if (unlikely(map->m_len > INT_MAX))
 519		map->m_len = INT_MAX;
 520
 521	/* We can handle the block number less than EXT_MAX_BLOCKS */
 522	if (unlikely(map->m_lblk >= EXT_MAX_BLOCKS))
 523		return -EFSCORRUPTED;
 524
 525	/* Lookup extent status tree firstly */
 526	if (ext4_es_lookup_extent(inode, map->m_lblk, &es)) {
 
 527		if (ext4_es_is_written(&es) || ext4_es_is_unwritten(&es)) {
 528			map->m_pblk = ext4_es_pblock(&es) +
 529					map->m_lblk - es.es_lblk;
 530			map->m_flags |= ext4_es_is_written(&es) ?
 531					EXT4_MAP_MAPPED : EXT4_MAP_UNWRITTEN;
 532			retval = es.es_len - (map->m_lblk - es.es_lblk);
 533			if (retval > map->m_len)
 534				retval = map->m_len;
 535			map->m_len = retval;
 536		} else if (ext4_es_is_delayed(&es) || ext4_es_is_hole(&es)) {
 537			map->m_pblk = 0;
 538			retval = es.es_len - (map->m_lblk - es.es_lblk);
 539			if (retval > map->m_len)
 540				retval = map->m_len;
 541			map->m_len = retval;
 542			retval = 0;
 543		} else {
 544			BUG_ON(1);
 545		}
 546#ifdef ES_AGGRESSIVE_TEST
 547		ext4_map_blocks_es_recheck(handle, inode, map,
 548					   &orig_map, flags);
 549#endif
 550		goto found;
 551	}
 552
 553	/*
 554	 * Try to see if we can get the block without requesting a new
 555	 * file system block.
 556	 */
 557	down_read(&EXT4_I(inode)->i_data_sem);
 558	if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) {
 559		retval = ext4_ext_map_blocks(handle, inode, map, flags &
 560					     EXT4_GET_BLOCKS_KEEP_SIZE);
 561	} else {
 562		retval = ext4_ind_map_blocks(handle, inode, map, flags &
 563					     EXT4_GET_BLOCKS_KEEP_SIZE);
 564	}
 565	if (retval > 0) {
 566		unsigned int status;
 567
 568		if (unlikely(retval != map->m_len)) {
 569			ext4_warning(inode->i_sb,
 570				     "ES len assertion failed for inode "
 571				     "%lu: retval %d != map->m_len %d",
 572				     inode->i_ino, retval, map->m_len);
 573			WARN_ON(1);
 574		}
 575
 576		status = map->m_flags & EXT4_MAP_UNWRITTEN ?
 577				EXTENT_STATUS_UNWRITTEN : EXTENT_STATUS_WRITTEN;
 578		if (!(flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE) &&
 579		    !(status & EXTENT_STATUS_WRITTEN) &&
 580		    ext4_find_delalloc_range(inode, map->m_lblk,
 581					     map->m_lblk + map->m_len - 1))
 582			status |= EXTENT_STATUS_DELAYED;
 583		ret = ext4_es_insert_extent(inode, map->m_lblk,
 584					    map->m_len, map->m_pblk, status);
 585		if (ret < 0)
 586			retval = ret;
 587	}
 588	up_read((&EXT4_I(inode)->i_data_sem));
 589
 590found:
 591	if (retval > 0 && map->m_flags & EXT4_MAP_MAPPED) {
 592		ret = check_block_validity(inode, map);
 593		if (ret != 0)
 594			return ret;
 595	}
 596
 597	/* If it is only a block(s) look up */
 598	if ((flags & EXT4_GET_BLOCKS_CREATE) == 0)
 599		return retval;
 600
 601	/*
 602	 * Returns if the blocks have already allocated
 603	 *
 604	 * Note that if blocks have been preallocated
 605	 * ext4_ext_get_block() returns the create = 0
 606	 * with buffer head unmapped.
 607	 */
 608	if (retval > 0 && map->m_flags & EXT4_MAP_MAPPED)
 609		/*
 610		 * If we need to convert extent to unwritten
 611		 * we continue and do the actual work in
 612		 * ext4_ext_map_blocks()
 613		 */
 614		if (!(flags & EXT4_GET_BLOCKS_CONVERT_UNWRITTEN))
 615			return retval;
 616
 617	/*
 618	 * Here we clear m_flags because after allocating an new extent,
 619	 * it will be set again.
 620	 */
 621	map->m_flags &= ~EXT4_MAP_FLAGS;
 622
 623	/*
 624	 * New blocks allocate and/or writing to unwritten extent
 625	 * will possibly result in updating i_data, so we take
 626	 * the write lock of i_data_sem, and call get_block()
 627	 * with create == 1 flag.
 628	 */
 629	down_write(&EXT4_I(inode)->i_data_sem);
 630
 631	/*
 632	 * We need to check for EXT4 here because migrate
 633	 * could have changed the inode type in between
 634	 */
 635	if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) {
 636		retval = ext4_ext_map_blocks(handle, inode, map, flags);
 637	} else {
 638		retval = ext4_ind_map_blocks(handle, inode, map, flags);
 639
 640		if (retval > 0 && map->m_flags & EXT4_MAP_NEW) {
 641			/*
 642			 * We allocated new blocks which will result in
 643			 * i_data's format changing.  Force the migrate
 644			 * to fail by clearing migrate flags
 645			 */
 646			ext4_clear_inode_state(inode, EXT4_STATE_EXT_MIGRATE);
 647		}
 648
 649		/*
 650		 * Update reserved blocks/metadata blocks after successful
 651		 * block allocation which had been deferred till now. We don't
 652		 * support fallocate for non extent files. So we can update
 653		 * reserve space here.
 654		 */
 655		if ((retval > 0) &&
 656			(flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE))
 657			ext4_da_update_reserve_space(inode, retval, 1);
 658	}
 659
 660	if (retval > 0) {
 661		unsigned int status;
 662
 663		if (unlikely(retval != map->m_len)) {
 664			ext4_warning(inode->i_sb,
 665				     "ES len assertion failed for inode "
 666				     "%lu: retval %d != map->m_len %d",
 667				     inode->i_ino, retval, map->m_len);
 668			WARN_ON(1);
 669		}
 670
 671		/*
 672		 * We have to zeroout blocks before inserting them into extent
 673		 * status tree. Otherwise someone could look them up there and
 674		 * use them before they are really zeroed. We also have to
 675		 * unmap metadata before zeroing as otherwise writeback can
 676		 * overwrite zeros with stale data from block device.
 677		 */
 678		if (flags & EXT4_GET_BLOCKS_ZERO &&
 679		    map->m_flags & EXT4_MAP_MAPPED &&
 680		    map->m_flags & EXT4_MAP_NEW) {
 681			clean_bdev_aliases(inode->i_sb->s_bdev, map->m_pblk,
 682					   map->m_len);
 683			ret = ext4_issue_zeroout(inode, map->m_lblk,
 684						 map->m_pblk, map->m_len);
 685			if (ret) {
 686				retval = ret;
 687				goto out_sem;
 688			}
 689		}
 690
 691		/*
 692		 * If the extent has been zeroed out, we don't need to update
 693		 * extent status tree.
 694		 */
 695		if ((flags & EXT4_GET_BLOCKS_PRE_IO) &&
 696		    ext4_es_lookup_extent(inode, map->m_lblk, &es)) {
 697			if (ext4_es_is_written(&es))
 698				goto out_sem;
 699		}
 700		status = map->m_flags & EXT4_MAP_UNWRITTEN ?
 701				EXTENT_STATUS_UNWRITTEN : EXTENT_STATUS_WRITTEN;
 702		if (!(flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE) &&
 703		    !(status & EXTENT_STATUS_WRITTEN) &&
 704		    ext4_find_delalloc_range(inode, map->m_lblk,
 705					     map->m_lblk + map->m_len - 1))
 706			status |= EXTENT_STATUS_DELAYED;
 707		ret = ext4_es_insert_extent(inode, map->m_lblk, map->m_len,
 708					    map->m_pblk, status);
 709		if (ret < 0) {
 710			retval = ret;
 711			goto out_sem;
 712		}
 713	}
 714
 715out_sem:
 716	up_write((&EXT4_I(inode)->i_data_sem));
 717	if (retval > 0 && map->m_flags & EXT4_MAP_MAPPED) {
 718		ret = check_block_validity(inode, map);
 719		if (ret != 0)
 720			return ret;
 721
 722		/*
 723		 * Inodes with freshly allocated blocks where contents will be
 724		 * visible after transaction commit must be on transaction's
 725		 * ordered data list.
 726		 */
 727		if (map->m_flags & EXT4_MAP_NEW &&
 728		    !(map->m_flags & EXT4_MAP_UNWRITTEN) &&
 729		    !(flags & EXT4_GET_BLOCKS_ZERO) &&
 730		    !ext4_is_quota_file(inode) &&
 731		    ext4_should_order_data(inode)) {
 
 
 
 
 732			if (flags & EXT4_GET_BLOCKS_IO_SUBMIT)
 733				ret = ext4_jbd2_inode_add_wait(handle, inode);
 
 734			else
 735				ret = ext4_jbd2_inode_add_write(handle, inode);
 
 736			if (ret)
 737				return ret;
 738		}
 
 
 739	}
 
 
 
 740	return retval;
 741}
 742
 743/*
 744 * Update EXT4_MAP_FLAGS in bh->b_state. For buffer heads attached to pages
 745 * we have to be careful as someone else may be manipulating b_state as well.
 746 */
 747static void ext4_update_bh_state(struct buffer_head *bh, unsigned long flags)
 748{
 749	unsigned long old_state;
 750	unsigned long new_state;
 751
 752	flags &= EXT4_MAP_FLAGS;
 753
 754	/* Dummy buffer_head? Set non-atomically. */
 755	if (!bh->b_page) {
 756		bh->b_state = (bh->b_state & ~EXT4_MAP_FLAGS) | flags;
 757		return;
 758	}
 759	/*
 760	 * Someone else may be modifying b_state. Be careful! This is ugly but
 761	 * once we get rid of using bh as a container for mapping information
 762	 * to pass to / from get_block functions, this can go away.
 763	 */
 764	do {
 765		old_state = READ_ONCE(bh->b_state);
 766		new_state = (old_state & ~EXT4_MAP_FLAGS) | flags;
 767	} while (unlikely(
 768		 cmpxchg(&bh->b_state, old_state, new_state) != old_state));
 769}
 770
 771static int _ext4_get_block(struct inode *inode, sector_t iblock,
 772			   struct buffer_head *bh, int flags)
 773{
 774	struct ext4_map_blocks map;
 775	int ret = 0;
 776
 777	if (ext4_has_inline_data(inode))
 778		return -ERANGE;
 779
 780	map.m_lblk = iblock;
 781	map.m_len = bh->b_size >> inode->i_blkbits;
 782
 783	ret = ext4_map_blocks(ext4_journal_current_handle(), inode, &map,
 784			      flags);
 785	if (ret > 0) {
 786		map_bh(bh, inode->i_sb, map.m_pblk);
 787		ext4_update_bh_state(bh, map.m_flags);
 788		bh->b_size = inode->i_sb->s_blocksize * map.m_len;
 789		ret = 0;
 790	} else if (ret == 0) {
 791		/* hole case, need to fill in bh->b_size */
 792		bh->b_size = inode->i_sb->s_blocksize * map.m_len;
 793	}
 794	return ret;
 795}
 796
 797int ext4_get_block(struct inode *inode, sector_t iblock,
 798		   struct buffer_head *bh, int create)
 799{
 800	return _ext4_get_block(inode, iblock, bh,
 801			       create ? EXT4_GET_BLOCKS_CREATE : 0);
 802}
 803
 804/*
 805 * Get block function used when preparing for buffered write if we require
 806 * creating an unwritten extent if blocks haven't been allocated.  The extent
 807 * will be converted to written after the IO is complete.
 808 */
 809int ext4_get_block_unwritten(struct inode *inode, sector_t iblock,
 810			     struct buffer_head *bh_result, int create)
 811{
 812	ext4_debug("ext4_get_block_unwritten: inode %lu, create flag %d\n",
 813		   inode->i_ino, create);
 814	return _ext4_get_block(inode, iblock, bh_result,
 815			       EXT4_GET_BLOCKS_IO_CREATE_EXT);
 816}
 817
 818/* Maximum number of blocks we map for direct IO at once. */
 819#define DIO_MAX_BLOCKS 4096
 820
 821/*
 822 * Get blocks function for the cases that need to start a transaction -
 823 * generally difference cases of direct IO and DAX IO. It also handles retries
 824 * in case of ENOSPC.
 825 */
 826static int ext4_get_block_trans(struct inode *inode, sector_t iblock,
 827				struct buffer_head *bh_result, int flags)
 828{
 829	int dio_credits;
 830	handle_t *handle;
 831	int retries = 0;
 832	int ret;
 833
 834	/* Trim mapping request to maximum we can map at once for DIO */
 835	if (bh_result->b_size >> inode->i_blkbits > DIO_MAX_BLOCKS)
 836		bh_result->b_size = DIO_MAX_BLOCKS << inode->i_blkbits;
 837	dio_credits = ext4_chunk_trans_blocks(inode,
 838				      bh_result->b_size >> inode->i_blkbits);
 839retry:
 840	handle = ext4_journal_start(inode, EXT4_HT_MAP_BLOCKS, dio_credits);
 841	if (IS_ERR(handle))
 842		return PTR_ERR(handle);
 843
 844	ret = _ext4_get_block(inode, iblock, bh_result, flags);
 845	ext4_journal_stop(handle);
 846
 847	if (ret == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
 848		goto retry;
 849	return ret;
 850}
 851
 852/* Get block function for DIO reads and writes to inodes without extents */
 853int ext4_dio_get_block(struct inode *inode, sector_t iblock,
 854		       struct buffer_head *bh, int create)
 855{
 856	/* We don't expect handle for direct IO */
 857	WARN_ON_ONCE(ext4_journal_current_handle());
 858
 859	if (!create)
 860		return _ext4_get_block(inode, iblock, bh, 0);
 861	return ext4_get_block_trans(inode, iblock, bh, EXT4_GET_BLOCKS_CREATE);
 862}
 863
 864/*
 865 * Get block function for AIO DIO writes when we create unwritten extent if
 866 * blocks are not allocated yet. The extent will be converted to written
 867 * after IO is complete.
 868 */
 869static int ext4_dio_get_block_unwritten_async(struct inode *inode,
 870		sector_t iblock, struct buffer_head *bh_result,	int create)
 871{
 872	int ret;
 873
 874	/* We don't expect handle for direct IO */
 875	WARN_ON_ONCE(ext4_journal_current_handle());
 876
 877	ret = ext4_get_block_trans(inode, iblock, bh_result,
 878				   EXT4_GET_BLOCKS_IO_CREATE_EXT);
 879
 880	/*
 881	 * When doing DIO using unwritten extents, we need io_end to convert
 882	 * unwritten extents to written on IO completion. We allocate io_end
 883	 * once we spot unwritten extent and store it in b_private. Generic
 884	 * DIO code keeps b_private set and furthermore passes the value to
 885	 * our completion callback in 'private' argument.
 886	 */
 887	if (!ret && buffer_unwritten(bh_result)) {
 888		if (!bh_result->b_private) {
 889			ext4_io_end_t *io_end;
 890
 891			io_end = ext4_init_io_end(inode, GFP_KERNEL);
 892			if (!io_end)
 893				return -ENOMEM;
 894			bh_result->b_private = io_end;
 895			ext4_set_io_unwritten_flag(inode, io_end);
 896		}
 897		set_buffer_defer_completion(bh_result);
 898	}
 899
 900	return ret;
 901}
 902
 903/*
 904 * Get block function for non-AIO DIO writes when we create unwritten extent if
 905 * blocks are not allocated yet. The extent will be converted to written
 906 * after IO is complete by ext4_direct_IO_write().
 907 */
 908static int ext4_dio_get_block_unwritten_sync(struct inode *inode,
 909		sector_t iblock, struct buffer_head *bh_result,	int create)
 910{
 911	int ret;
 912
 913	/* We don't expect handle for direct IO */
 914	WARN_ON_ONCE(ext4_journal_current_handle());
 915
 916	ret = ext4_get_block_trans(inode, iblock, bh_result,
 917				   EXT4_GET_BLOCKS_IO_CREATE_EXT);
 918
 919	/*
 920	 * Mark inode as having pending DIO writes to unwritten extents.
 921	 * ext4_direct_IO_write() checks this flag and converts extents to
 922	 * written.
 923	 */
 924	if (!ret && buffer_unwritten(bh_result))
 925		ext4_set_inode_state(inode, EXT4_STATE_DIO_UNWRITTEN);
 926
 927	return ret;
 928}
 929
 930static int ext4_dio_get_block_overwrite(struct inode *inode, sector_t iblock,
 931		   struct buffer_head *bh_result, int create)
 932{
 933	int ret;
 934
 935	ext4_debug("ext4_dio_get_block_overwrite: inode %lu, create flag %d\n",
 936		   inode->i_ino, create);
 937	/* We don't expect handle for direct IO */
 938	WARN_ON_ONCE(ext4_journal_current_handle());
 939
 940	ret = _ext4_get_block(inode, iblock, bh_result, 0);
 941	/*
 942	 * Blocks should have been preallocated! ext4_file_write_iter() checks
 943	 * that.
 944	 */
 945	WARN_ON_ONCE(!buffer_mapped(bh_result) || buffer_unwritten(bh_result));
 946
 947	return ret;
 948}
 949
 950
 951/*
 952 * `handle' can be NULL if create is zero
 953 */
 954struct buffer_head *ext4_getblk(handle_t *handle, struct inode *inode,
 955				ext4_lblk_t block, int map_flags)
 956{
 957	struct ext4_map_blocks map;
 958	struct buffer_head *bh;
 959	int create = map_flags & EXT4_GET_BLOCKS_CREATE;
 960	int err;
 961
 962	J_ASSERT(handle != NULL || create == 0);
 
 963
 964	map.m_lblk = block;
 965	map.m_len = 1;
 966	err = ext4_map_blocks(handle, inode, &map, map_flags);
 967
 968	if (err == 0)
 969		return create ? ERR_PTR(-ENOSPC) : NULL;
 970	if (err < 0)
 971		return ERR_PTR(err);
 972
 973	bh = sb_getblk(inode->i_sb, map.m_pblk);
 974	if (unlikely(!bh))
 975		return ERR_PTR(-ENOMEM);
 976	if (map.m_flags & EXT4_MAP_NEW) {
 977		J_ASSERT(create != 0);
 978		J_ASSERT(handle != NULL);
 
 979
 980		/*
 981		 * Now that we do not always journal data, we should
 982		 * keep in mind whether this should always journal the
 983		 * new buffer as metadata.  For now, regular file
 984		 * writes use ext4_get_block instead, so it's not a
 985		 * problem.
 986		 */
 987		lock_buffer(bh);
 988		BUFFER_TRACE(bh, "call get_create_access");
 989		err = ext4_journal_get_create_access(handle, bh);
 990		if (unlikely(err)) {
 991			unlock_buffer(bh);
 992			goto errout;
 993		}
 994		if (!buffer_uptodate(bh)) {
 995			memset(bh->b_data, 0, inode->i_sb->s_blocksize);
 996			set_buffer_uptodate(bh);
 997		}
 998		unlock_buffer(bh);
 999		BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
1000		err = ext4_handle_dirty_metadata(handle, inode, bh);
1001		if (unlikely(err))
1002			goto errout;
1003	} else
1004		BUFFER_TRACE(bh, "not a new buffer");
1005	return bh;
1006errout:
1007	brelse(bh);
1008	return ERR_PTR(err);
1009}
1010
1011struct buffer_head *ext4_bread(handle_t *handle, struct inode *inode,
1012			       ext4_lblk_t block, int map_flags)
1013{
1014	struct buffer_head *bh;
 
1015
1016	bh = ext4_getblk(handle, inode, block, map_flags);
1017	if (IS_ERR(bh))
1018		return bh;
1019	if (!bh || buffer_uptodate(bh))
1020		return bh;
1021	ll_rw_block(REQ_OP_READ, REQ_META | REQ_PRIO, 1, &bh);
1022	wait_on_buffer(bh);
1023	if (buffer_uptodate(bh))
1024		return bh;
1025	put_bh(bh);
1026	return ERR_PTR(-EIO);
 
 
 
 
 
1027}
1028
1029/* Read a contiguous batch of blocks. */
1030int ext4_bread_batch(struct inode *inode, ext4_lblk_t block, int bh_count,
1031		     bool wait, struct buffer_head **bhs)
1032{
1033	int i, err;
1034
1035	for (i = 0; i < bh_count; i++) {
1036		bhs[i] = ext4_getblk(NULL, inode, block + i, 0 /* map_flags */);
1037		if (IS_ERR(bhs[i])) {
1038			err = PTR_ERR(bhs[i]);
1039			bh_count = i;
1040			goto out_brelse;
1041		}
1042	}
1043
1044	for (i = 0; i < bh_count; i++)
1045		/* Note that NULL bhs[i] is valid because of holes. */
1046		if (bhs[i] && !buffer_uptodate(bhs[i]))
1047			ll_rw_block(REQ_OP_READ, REQ_META | REQ_PRIO, 1,
1048				    &bhs[i]);
1049
1050	if (!wait)
1051		return 0;
1052
1053	for (i = 0; i < bh_count; i++)
1054		if (bhs[i])
1055			wait_on_buffer(bhs[i]);
1056
1057	for (i = 0; i < bh_count; i++) {
1058		if (bhs[i] && !buffer_uptodate(bhs[i])) {
1059			err = -EIO;
1060			goto out_brelse;
1061		}
1062	}
1063	return 0;
1064
1065out_brelse:
1066	for (i = 0; i < bh_count; i++) {
1067		brelse(bhs[i]);
1068		bhs[i] = NULL;
1069	}
1070	return err;
1071}
1072
1073int ext4_walk_page_buffers(handle_t *handle,
1074			   struct buffer_head *head,
1075			   unsigned from,
1076			   unsigned to,
1077			   int *partial,
1078			   int (*fn)(handle_t *handle,
1079				     struct buffer_head *bh))
1080{
1081	struct buffer_head *bh;
1082	unsigned block_start, block_end;
1083	unsigned blocksize = head->b_size;
1084	int err, ret = 0;
1085	struct buffer_head *next;
1086
1087	for (bh = head, block_start = 0;
1088	     ret == 0 && (bh != head || !block_start);
1089	     block_start = block_end, bh = next) {
1090		next = bh->b_this_page;
1091		block_end = block_start + blocksize;
1092		if (block_end <= from || block_start >= to) {
1093			if (partial && !buffer_uptodate(bh))
1094				*partial = 1;
1095			continue;
1096		}
1097		err = (*fn)(handle, bh);
1098		if (!ret)
1099			ret = err;
1100	}
1101	return ret;
1102}
1103
1104/*
1105 * To preserve ordering, it is essential that the hole instantiation and
1106 * the data write be encapsulated in a single transaction.  We cannot
1107 * close off a transaction and start a new one between the ext4_get_block()
1108 * and the commit_write().  So doing the jbd2_journal_start at the start of
1109 * prepare_write() is the right place.
1110 *
1111 * Also, this function can nest inside ext4_writepage().  In that case, we
1112 * *know* that ext4_writepage() has generated enough buffer credits to do the
1113 * whole page.  So we won't block on the journal in that case, which is good,
1114 * because the caller may be PF_MEMALLOC.
1115 *
1116 * By accident, ext4 can be reentered when a transaction is open via
1117 * quota file writes.  If we were to commit the transaction while thus
1118 * reentered, there can be a deadlock - we would be holding a quota
1119 * lock, and the commit would never complete if another thread had a
1120 * transaction open and was blocking on the quota lock - a ranking
1121 * violation.
1122 *
1123 * So what we do is to rely on the fact that jbd2_journal_stop/journal_start
1124 * will _not_ run commit under these circumstances because handle->h_ref
1125 * is elevated.  We'll still have enough credits for the tiny quotafile
1126 * write.
1127 */
1128int do_journal_get_write_access(handle_t *handle,
1129				struct buffer_head *bh)
1130{
1131	int dirty = buffer_dirty(bh);
1132	int ret;
1133
1134	if (!buffer_mapped(bh) || buffer_freed(bh))
1135		return 0;
1136	/*
1137	 * __block_write_begin() could have dirtied some buffers. Clean
1138	 * the dirty bit as jbd2_journal_get_write_access() could complain
1139	 * otherwise about fs integrity issues. Setting of the dirty bit
1140	 * by __block_write_begin() isn't a real problem here as we clear
1141	 * the bit before releasing a page lock and thus writeback cannot
1142	 * ever write the buffer.
1143	 */
1144	if (dirty)
1145		clear_buffer_dirty(bh);
1146	BUFFER_TRACE(bh, "get write access");
1147	ret = ext4_journal_get_write_access(handle, bh);
1148	if (!ret && dirty)
1149		ret = ext4_handle_dirty_metadata(handle, NULL, bh);
1150	return ret;
1151}
1152
1153#ifdef CONFIG_EXT4_FS_ENCRYPTION
1154static int ext4_block_write_begin(struct page *page, loff_t pos, unsigned len,
1155				  get_block_t *get_block)
1156{
1157	unsigned from = pos & (PAGE_SIZE - 1);
1158	unsigned to = from + len;
1159	struct inode *inode = page->mapping->host;
1160	unsigned block_start, block_end;
1161	sector_t block;
1162	int err = 0;
1163	unsigned blocksize = inode->i_sb->s_blocksize;
1164	unsigned bbits;
1165	struct buffer_head *bh, *head, *wait[2], **wait_bh = wait;
1166	bool decrypt = false;
 
1167
1168	BUG_ON(!PageLocked(page));
1169	BUG_ON(from > PAGE_SIZE);
1170	BUG_ON(to > PAGE_SIZE);
1171	BUG_ON(from > to);
1172
1173	if (!page_has_buffers(page))
1174		create_empty_buffers(page, blocksize, 0);
1175	head = page_buffers(page);
1176	bbits = ilog2(blocksize);
1177	block = (sector_t)page->index << (PAGE_SHIFT - bbits);
1178
1179	for (bh = head, block_start = 0; bh != head || !block_start;
1180	    block++, block_start = block_end, bh = bh->b_this_page) {
1181		block_end = block_start + blocksize;
1182		if (block_end <= from || block_start >= to) {
1183			if (PageUptodate(page)) {
1184				if (!buffer_uptodate(bh))
1185					set_buffer_uptodate(bh);
1186			}
1187			continue;
1188		}
1189		if (buffer_new(bh))
1190			clear_buffer_new(bh);
1191		if (!buffer_mapped(bh)) {
1192			WARN_ON(bh->b_size != blocksize);
1193			err = get_block(inode, block, bh, 1);
1194			if (err)
1195				break;
1196			if (buffer_new(bh)) {
1197				clean_bdev_bh_alias(bh);
1198				if (PageUptodate(page)) {
1199					clear_buffer_new(bh);
1200					set_buffer_uptodate(bh);
1201					mark_buffer_dirty(bh);
1202					continue;
1203				}
1204				if (block_end > to || block_start < from)
1205					zero_user_segments(page, to, block_end,
1206							   block_start, from);
1207				continue;
1208			}
1209		}
1210		if (PageUptodate(page)) {
1211			if (!buffer_uptodate(bh))
1212				set_buffer_uptodate(bh);
1213			continue;
1214		}
1215		if (!buffer_uptodate(bh) && !buffer_delay(bh) &&
1216		    !buffer_unwritten(bh) &&
1217		    (block_start < from || block_end > to)) {
1218			ll_rw_block(REQ_OP_READ, 0, 1, &bh);
1219			*wait_bh++ = bh;
1220			decrypt = ext4_encrypted_inode(inode) &&
1221				S_ISREG(inode->i_mode);
1222		}
1223	}
1224	/*
1225	 * If we issued read requests, let them complete.
1226	 */
1227	while (wait_bh > wait) {
1228		wait_on_buffer(*--wait_bh);
1229		if (!buffer_uptodate(*wait_bh))
1230			err = -EIO;
1231	}
1232	if (unlikely(err))
1233		page_zero_new_buffers(page, from, to);
1234	else if (decrypt)
1235		err = fscrypt_decrypt_page(page->mapping->host, page,
1236				PAGE_SIZE, 0, page->index);
 
 
 
 
 
 
 
 
 
 
1237	return err;
1238}
1239#endif
1240
1241static int ext4_write_begin(struct file *file, struct address_space *mapping,
1242			    loff_t pos, unsigned len, unsigned flags,
1243			    struct page **pagep, void **fsdata)
1244{
1245	struct inode *inode = mapping->host;
1246	int ret, needed_blocks;
1247	handle_t *handle;
1248	int retries = 0;
1249	struct page *page;
1250	pgoff_t index;
1251	unsigned from, to;
1252
1253	if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb))))
1254		return -EIO;
1255
1256	trace_ext4_write_begin(inode, pos, len, flags);
1257	/*
1258	 * Reserve one block more for addition to orphan list in case
1259	 * we allocate blocks but write fails for some reason
1260	 */
1261	needed_blocks = ext4_writepage_trans_blocks(inode) + 1;
1262	index = pos >> PAGE_SHIFT;
1263	from = pos & (PAGE_SIZE - 1);
1264	to = from + len;
1265
1266	if (ext4_test_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA)) {
1267		ret = ext4_try_to_write_inline_data(mapping, inode, pos, len,
1268						    flags, pagep);
1269		if (ret < 0)
1270			return ret;
1271		if (ret == 1)
1272			return 0;
1273	}
1274
1275	/*
1276	 * grab_cache_page_write_begin() can take a long time if the
1277	 * system is thrashing due to memory pressure, or if the page
1278	 * is being written back.  So grab it first before we start
1279	 * the transaction handle.  This also allows us to allocate
1280	 * the page (if needed) without using GFP_NOFS.
1281	 */
1282retry_grab:
1283	page = grab_cache_page_write_begin(mapping, index, flags);
1284	if (!page)
1285		return -ENOMEM;
1286	unlock_page(page);
1287
1288retry_journal:
1289	handle = ext4_journal_start(inode, EXT4_HT_WRITE_PAGE, needed_blocks);
1290	if (IS_ERR(handle)) {
1291		put_page(page);
1292		return PTR_ERR(handle);
1293	}
1294
1295	lock_page(page);
1296	if (page->mapping != mapping) {
1297		/* The page got truncated from under us */
1298		unlock_page(page);
1299		put_page(page);
1300		ext4_journal_stop(handle);
1301		goto retry_grab;
1302	}
1303	/* In case writeback began while the page was unlocked */
1304	wait_for_stable_page(page);
1305
1306#ifdef CONFIG_EXT4_FS_ENCRYPTION
1307	if (ext4_should_dioread_nolock(inode))
1308		ret = ext4_block_write_begin(page, pos, len,
1309					     ext4_get_block_unwritten);
1310	else
1311		ret = ext4_block_write_begin(page, pos, len,
1312					     ext4_get_block);
1313#else
1314	if (ext4_should_dioread_nolock(inode))
1315		ret = __block_write_begin(page, pos, len,
1316					  ext4_get_block_unwritten);
1317	else
1318		ret = __block_write_begin(page, pos, len, ext4_get_block);
1319#endif
1320	if (!ret && ext4_should_journal_data(inode)) {
1321		ret = ext4_walk_page_buffers(handle, page_buffers(page),
1322					     from, to, NULL,
1323					     do_journal_get_write_access);
1324	}
1325
1326	if (ret) {
 
 
 
1327		unlock_page(page);
1328		/*
1329		 * __block_write_begin may have instantiated a few blocks
1330		 * outside i_size.  Trim these off again. Don't need
1331		 * i_size_read because we hold i_mutex.
1332		 *
1333		 * Add inode to orphan list in case we crash before
1334		 * truncate finishes
1335		 */
1336		if (pos + len > inode->i_size && ext4_can_truncate(inode))
1337			ext4_orphan_add(handle, inode);
1338
1339		ext4_journal_stop(handle);
1340		if (pos + len > inode->i_size) {
1341			ext4_truncate_failed_write(inode);
1342			/*
1343			 * If truncate failed early the inode might
1344			 * still be on the orphan list; we need to
1345			 * make sure the inode is removed from the
1346			 * orphan list in that case.
1347			 */
1348			if (inode->i_nlink)
1349				ext4_orphan_del(NULL, inode);
1350		}
1351
1352		if (ret == -ENOSPC &&
1353		    ext4_should_retry_alloc(inode->i_sb, &retries))
1354			goto retry_journal;
1355		put_page(page);
1356		return ret;
1357	}
1358	*pagep = page;
1359	return ret;
1360}
1361
1362/* For write_end() in data=journal mode */
1363static int write_end_fn(handle_t *handle, struct buffer_head *bh)
1364{
1365	int ret;
1366	if (!buffer_mapped(bh) || buffer_freed(bh))
1367		return 0;
1368	set_buffer_uptodate(bh);
1369	ret = ext4_handle_dirty_metadata(handle, NULL, bh);
1370	clear_buffer_meta(bh);
1371	clear_buffer_prio(bh);
1372	return ret;
1373}
1374
1375/*
1376 * We need to pick up the new inode size which generic_commit_write gave us
1377 * `file' can be NULL - eg, when called from page_symlink().
1378 *
1379 * ext4 never places buffers on inode->i_mapping->private_list.  metadata
1380 * buffers are managed internally.
1381 */
1382static int ext4_write_end(struct file *file,
1383			  struct address_space *mapping,
1384			  loff_t pos, unsigned len, unsigned copied,
1385			  struct page *page, void *fsdata)
1386{
1387	handle_t *handle = ext4_journal_current_handle();
1388	struct inode *inode = mapping->host;
1389	loff_t old_size = inode->i_size;
1390	int ret = 0, ret2;
1391	int i_size_changed = 0;
 
 
1392
1393	trace_ext4_write_end(inode, pos, len, copied);
1394	if (ext4_has_inline_data(inode)) {
1395		ret = ext4_write_inline_data_end(inode, pos, len,
1396						 copied, page);
1397		if (ret < 0) {
1398			unlock_page(page);
1399			put_page(page);
1400			goto errout;
1401		}
1402		copied = ret;
 
1403	} else
1404		copied = block_write_end(file, mapping, pos,
1405					 len, copied, page, fsdata);
1406	/*
1407	 * it's important to update i_size while still holding page lock:
1408	 * page writeout could otherwise come in and zero beyond i_size.
 
 
 
1409	 */
1410	i_size_changed = ext4_update_inode_size(inode, pos + copied);
 
1411	unlock_page(page);
1412	put_page(page);
1413
1414	if (old_size < pos)
1415		pagecache_isize_extended(inode, old_size, pos);
1416	/*
1417	 * Don't mark the inode dirty under page lock. First, it unnecessarily
1418	 * makes the holding time of page lock longer. Second, it forces lock
1419	 * ordering of page lock and transaction start for journaling
1420	 * filesystems.
1421	 */
1422	if (i_size_changed)
1423		ext4_mark_inode_dirty(handle, inode);
1424
1425	if (pos + len > inode->i_size && ext4_can_truncate(inode))
 
1426		/* if we have allocated more blocks and copied
1427		 * less. We will have blocks allocated outside
1428		 * inode->i_size. So truncate them
1429		 */
1430		ext4_orphan_add(handle, inode);
1431errout:
1432	ret2 = ext4_journal_stop(handle);
1433	if (!ret)
1434		ret = ret2;
1435
1436	if (pos + len > inode->i_size) {
1437		ext4_truncate_failed_write(inode);
1438		/*
1439		 * If truncate failed early the inode might still be
1440		 * on the orphan list; we need to make sure the inode
1441		 * is removed from the orphan list in that case.
1442		 */
1443		if (inode->i_nlink)
1444			ext4_orphan_del(NULL, inode);
1445	}
1446
1447	return ret ? ret : copied;
1448}
1449
1450/*
1451 * This is a private version of page_zero_new_buffers() which doesn't
1452 * set the buffer to be dirty, since in data=journalled mode we need
1453 * to call ext4_handle_dirty_metadata() instead.
1454 */
1455static void ext4_journalled_zero_new_buffers(handle_t *handle,
1456					    struct page *page,
1457					    unsigned from, unsigned to)
1458{
1459	unsigned int block_start = 0, block_end;
1460	struct buffer_head *head, *bh;
1461
1462	bh = head = page_buffers(page);
1463	do {
1464		block_end = block_start + bh->b_size;
1465		if (buffer_new(bh)) {
1466			if (block_end > from && block_start < to) {
1467				if (!PageUptodate(page)) {
1468					unsigned start, size;
1469
1470					start = max(from, block_start);
1471					size = min(to, block_end) - start;
1472
1473					zero_user(page, start, size);
1474					write_end_fn(handle, bh);
1475				}
1476				clear_buffer_new(bh);
1477			}
1478		}
1479		block_start = block_end;
1480		bh = bh->b_this_page;
1481	} while (bh != head);
1482}
1483
1484static int ext4_journalled_write_end(struct file *file,
1485				     struct address_space *mapping,
1486				     loff_t pos, unsigned len, unsigned copied,
1487				     struct page *page, void *fsdata)
1488{
1489	handle_t *handle = ext4_journal_current_handle();
1490	struct inode *inode = mapping->host;
1491	loff_t old_size = inode->i_size;
1492	int ret = 0, ret2;
1493	int partial = 0;
1494	unsigned from, to;
1495	int size_changed = 0;
 
 
1496
1497	trace_ext4_journalled_write_end(inode, pos, len, copied);
1498	from = pos & (PAGE_SIZE - 1);
1499	to = from + len;
1500
1501	BUG_ON(!ext4_handle_valid(handle));
1502
1503	if (ext4_has_inline_data(inode)) {
1504		ret = ext4_write_inline_data_end(inode, pos, len,
1505						 copied, page);
1506		if (ret < 0) {
1507			unlock_page(page);
1508			put_page(page);
1509			goto errout;
1510		}
1511		copied = ret;
 
1512	} else if (unlikely(copied < len) && !PageUptodate(page)) {
1513		copied = 0;
1514		ext4_journalled_zero_new_buffers(handle, page, from, to);
1515	} else {
1516		if (unlikely(copied < len))
1517			ext4_journalled_zero_new_buffers(handle, page,
1518							 from + copied, to);
1519		ret = ext4_walk_page_buffers(handle, page_buffers(page), from,
1520					     from + copied, &partial,
1521					     write_end_fn);
1522		if (!partial)
1523			SetPageUptodate(page);
1524	}
1525	size_changed = ext4_update_inode_size(inode, pos + copied);
 
1526	ext4_set_inode_state(inode, EXT4_STATE_JDATA);
1527	EXT4_I(inode)->i_datasync_tid = handle->h_transaction->t_tid;
1528	unlock_page(page);
1529	put_page(page);
1530
1531	if (old_size < pos)
1532		pagecache_isize_extended(inode, old_size, pos);
1533
1534	if (size_changed) {
1535		ret2 = ext4_mark_inode_dirty(handle, inode);
1536		if (!ret)
1537			ret = ret2;
1538	}
1539
1540	if (pos + len > inode->i_size && ext4_can_truncate(inode))
 
1541		/* if we have allocated more blocks and copied
1542		 * less. We will have blocks allocated outside
1543		 * inode->i_size. So truncate them
1544		 */
1545		ext4_orphan_add(handle, inode);
1546
1547errout:
1548	ret2 = ext4_journal_stop(handle);
1549	if (!ret)
1550		ret = ret2;
1551	if (pos + len > inode->i_size) {
1552		ext4_truncate_failed_write(inode);
1553		/*
1554		 * If truncate failed early the inode might still be
1555		 * on the orphan list; we need to make sure the inode
1556		 * is removed from the orphan list in that case.
1557		 */
1558		if (inode->i_nlink)
1559			ext4_orphan_del(NULL, inode);
1560	}
1561
1562	return ret ? ret : copied;
1563}
1564
1565/*
1566 * Reserve space for a single cluster
1567 */
1568static int ext4_da_reserve_space(struct inode *inode)
1569{
1570	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
1571	struct ext4_inode_info *ei = EXT4_I(inode);
1572	int ret;
1573
1574	/*
1575	 * We will charge metadata quota at writeout time; this saves
1576	 * us from metadata over-estimation, though we may go over by
1577	 * a small amount in the end.  Here we just reserve for data.
1578	 */
1579	ret = dquot_reserve_block(inode, EXT4_C2B(sbi, 1));
1580	if (ret)
1581		return ret;
1582
1583	spin_lock(&ei->i_block_reservation_lock);
1584	if (ext4_claim_free_clusters(sbi, 1, 0)) {
1585		spin_unlock(&ei->i_block_reservation_lock);
1586		dquot_release_reservation_block(inode, EXT4_C2B(sbi, 1));
1587		return -ENOSPC;
1588	}
1589	ei->i_reserved_data_blocks++;
1590	trace_ext4_da_reserve_space(inode);
1591	spin_unlock(&ei->i_block_reservation_lock);
1592
1593	return 0;       /* success */
1594}
1595
1596static void ext4_da_release_space(struct inode *inode, int to_free)
1597{
1598	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
1599	struct ext4_inode_info *ei = EXT4_I(inode);
1600
1601	if (!to_free)
1602		return;		/* Nothing to release, exit */
1603
1604	spin_lock(&EXT4_I(inode)->i_block_reservation_lock);
1605
1606	trace_ext4_da_release_space(inode, to_free);
1607	if (unlikely(to_free > ei->i_reserved_data_blocks)) {
1608		/*
1609		 * if there aren't enough reserved blocks, then the
1610		 * counter is messed up somewhere.  Since this
1611		 * function is called from invalidate page, it's
1612		 * harmless to return without any action.
1613		 */
1614		ext4_warning(inode->i_sb, "ext4_da_release_space: "
1615			 "ino %lu, to_free %d with only %d reserved "
1616			 "data blocks", inode->i_ino, to_free,
1617			 ei->i_reserved_data_blocks);
1618		WARN_ON(1);
1619		to_free = ei->i_reserved_data_blocks;
1620	}
1621	ei->i_reserved_data_blocks -= to_free;
1622
1623	/* update fs dirty data blocks counter */
1624	percpu_counter_sub(&sbi->s_dirtyclusters_counter, to_free);
1625
1626	spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
1627
1628	dquot_release_reservation_block(inode, EXT4_C2B(sbi, to_free));
1629}
1630
1631static void ext4_da_page_release_reservation(struct page *page,
1632					     unsigned int offset,
1633					     unsigned int length)
1634{
1635	int to_release = 0, contiguous_blks = 0;
1636	struct buffer_head *head, *bh;
1637	unsigned int curr_off = 0;
1638	struct inode *inode = page->mapping->host;
1639	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
1640	unsigned int stop = offset + length;
1641	int num_clusters;
1642	ext4_fsblk_t lblk;
1643
1644	BUG_ON(stop > PAGE_SIZE || stop < length);
1645
1646	head = page_buffers(page);
1647	bh = head;
1648	do {
1649		unsigned int next_off = curr_off + bh->b_size;
1650
1651		if (next_off > stop)
1652			break;
1653
1654		if ((offset <= curr_off) && (buffer_delay(bh))) {
1655			to_release++;
1656			contiguous_blks++;
1657			clear_buffer_delay(bh);
1658		} else if (contiguous_blks) {
1659			lblk = page->index <<
1660			       (PAGE_SHIFT - inode->i_blkbits);
1661			lblk += (curr_off >> inode->i_blkbits) -
1662				contiguous_blks;
1663			ext4_es_remove_extent(inode, lblk, contiguous_blks);
1664			contiguous_blks = 0;
1665		}
1666		curr_off = next_off;
1667	} while ((bh = bh->b_this_page) != head);
1668
1669	if (contiguous_blks) {
1670		lblk = page->index << (PAGE_SHIFT - inode->i_blkbits);
1671		lblk += (curr_off >> inode->i_blkbits) - contiguous_blks;
1672		ext4_es_remove_extent(inode, lblk, contiguous_blks);
1673	}
1674
1675	/* If we have released all the blocks belonging to a cluster, then we
1676	 * need to release the reserved space for that cluster. */
1677	num_clusters = EXT4_NUM_B2C(sbi, to_release);
1678	while (num_clusters > 0) {
1679		lblk = (page->index << (PAGE_SHIFT - inode->i_blkbits)) +
1680			((num_clusters - 1) << sbi->s_cluster_bits);
1681		if (sbi->s_cluster_ratio == 1 ||
1682		    !ext4_find_delalloc_cluster(inode, lblk))
1683			ext4_da_release_space(inode, 1);
1684
1685		num_clusters--;
1686	}
1687}
1688
1689/*
1690 * Delayed allocation stuff
1691 */
1692
1693struct mpage_da_data {
1694	struct inode *inode;
1695	struct writeback_control *wbc;
1696
1697	pgoff_t first_page;	/* The first page to write */
1698	pgoff_t next_page;	/* Current page to examine */
1699	pgoff_t last_page;	/* Last page to examine */
1700	/*
1701	 * Extent to map - this can be after first_page because that can be
1702	 * fully mapped. We somewhat abuse m_flags to store whether the extent
1703	 * is delalloc or unwritten.
1704	 */
1705	struct ext4_map_blocks map;
1706	struct ext4_io_submit io_submit;	/* IO submission data */
1707	unsigned int do_map:1;
 
1708};
1709
1710static void mpage_release_unused_pages(struct mpage_da_data *mpd,
1711				       bool invalidate)
1712{
1713	int nr_pages, i;
1714	pgoff_t index, end;
1715	struct pagevec pvec;
1716	struct inode *inode = mpd->inode;
1717	struct address_space *mapping = inode->i_mapping;
1718
1719	/* This is necessary when next_page == 0. */
1720	if (mpd->first_page >= mpd->next_page)
1721		return;
1722
 
1723	index = mpd->first_page;
1724	end   = mpd->next_page - 1;
1725	if (invalidate) {
1726		ext4_lblk_t start, last;
1727		start = index << (PAGE_SHIFT - inode->i_blkbits);
1728		last = end << (PAGE_SHIFT - inode->i_blkbits);
1729		ext4_es_remove_extent(inode, start, last - start + 1);
1730	}
1731
1732	pagevec_init(&pvec);
1733	while (index <= end) {
1734		nr_pages = pagevec_lookup_range(&pvec, mapping, &index, end);
1735		if (nr_pages == 0)
1736			break;
1737		for (i = 0; i < nr_pages; i++) {
1738			struct page *page = pvec.pages[i];
1739
1740			BUG_ON(!PageLocked(page));
1741			BUG_ON(PageWriteback(page));
1742			if (invalidate) {
1743				if (page_mapped(page))
1744					clear_page_dirty_for_io(page);
1745				block_invalidatepage(page, 0, PAGE_SIZE);
1746				ClearPageUptodate(page);
1747			}
1748			unlock_page(page);
1749		}
1750		pagevec_release(&pvec);
1751	}
1752}
1753
1754static void ext4_print_free_blocks(struct inode *inode)
1755{
1756	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
1757	struct super_block *sb = inode->i_sb;
1758	struct ext4_inode_info *ei = EXT4_I(inode);
1759
1760	ext4_msg(sb, KERN_CRIT, "Total free blocks count %lld",
1761	       EXT4_C2B(EXT4_SB(inode->i_sb),
1762			ext4_count_free_clusters(sb)));
1763	ext4_msg(sb, KERN_CRIT, "Free/Dirty block details");
1764	ext4_msg(sb, KERN_CRIT, "free_blocks=%lld",
1765	       (long long) EXT4_C2B(EXT4_SB(sb),
1766		percpu_counter_sum(&sbi->s_freeclusters_counter)));
1767	ext4_msg(sb, KERN_CRIT, "dirty_blocks=%lld",
1768	       (long long) EXT4_C2B(EXT4_SB(sb),
1769		percpu_counter_sum(&sbi->s_dirtyclusters_counter)));
1770	ext4_msg(sb, KERN_CRIT, "Block reservation details");
1771	ext4_msg(sb, KERN_CRIT, "i_reserved_data_blocks=%u",
1772		 ei->i_reserved_data_blocks);
1773	return;
1774}
1775
1776static int ext4_bh_delay_or_unwritten(handle_t *handle, struct buffer_head *bh)
1777{
1778	return (buffer_delay(bh) || buffer_unwritten(bh)) && buffer_dirty(bh);
1779}
1780
1781/*
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1782 * This function is grabs code from the very beginning of
1783 * ext4_map_blocks, but assumes that the caller is from delayed write
1784 * time. This function looks up the requested blocks and sets the
1785 * buffer delay bit under the protection of i_data_sem.
1786 */
1787static int ext4_da_map_blocks(struct inode *inode, sector_t iblock,
1788			      struct ext4_map_blocks *map,
1789			      struct buffer_head *bh)
1790{
1791	struct extent_status es;
1792	int retval;
1793	sector_t invalid_block = ~((sector_t) 0xffff);
1794#ifdef ES_AGGRESSIVE_TEST
1795	struct ext4_map_blocks orig_map;
1796
1797	memcpy(&orig_map, map, sizeof(*map));
1798#endif
1799
1800	if (invalid_block < ext4_blocks_count(EXT4_SB(inode->i_sb)->s_es))
1801		invalid_block = ~0;
1802
1803	map->m_flags = 0;
1804	ext_debug("ext4_da_map_blocks(): inode %lu, max_blocks %u,"
1805		  "logical block %lu\n", inode->i_ino, map->m_len,
1806		  (unsigned long) map->m_lblk);
1807
1808	/* Lookup extent status tree firstly */
1809	if (ext4_es_lookup_extent(inode, iblock, &es)) {
1810		if (ext4_es_is_hole(&es)) {
1811			retval = 0;
1812			down_read(&EXT4_I(inode)->i_data_sem);
1813			goto add_delayed;
1814		}
1815
1816		/*
1817		 * Delayed extent could be allocated by fallocate.
1818		 * So we need to check it.
1819		 */
1820		if (ext4_es_is_delayed(&es) && !ext4_es_is_unwritten(&es)) {
1821			map_bh(bh, inode->i_sb, invalid_block);
1822			set_buffer_new(bh);
1823			set_buffer_delay(bh);
1824			return 0;
1825		}
1826
1827		map->m_pblk = ext4_es_pblock(&es) + iblock - es.es_lblk;
1828		retval = es.es_len - (iblock - es.es_lblk);
1829		if (retval > map->m_len)
1830			retval = map->m_len;
1831		map->m_len = retval;
1832		if (ext4_es_is_written(&es))
1833			map->m_flags |= EXT4_MAP_MAPPED;
1834		else if (ext4_es_is_unwritten(&es))
1835			map->m_flags |= EXT4_MAP_UNWRITTEN;
1836		else
1837			BUG_ON(1);
1838
1839#ifdef ES_AGGRESSIVE_TEST
1840		ext4_map_blocks_es_recheck(NULL, inode, map, &orig_map, 0);
1841#endif
1842		return retval;
1843	}
1844
1845	/*
1846	 * Try to see if we can get the block without requesting a new
1847	 * file system block.
1848	 */
1849	down_read(&EXT4_I(inode)->i_data_sem);
1850	if (ext4_has_inline_data(inode))
1851		retval = 0;
1852	else if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
1853		retval = ext4_ext_map_blocks(NULL, inode, map, 0);
1854	else
1855		retval = ext4_ind_map_blocks(NULL, inode, map, 0);
1856
1857add_delayed:
1858	if (retval == 0) {
1859		int ret;
 
1860		/*
1861		 * XXX: __block_prepare_write() unmaps passed block,
1862		 * is it OK?
1863		 */
1864		/*
1865		 * If the block was allocated from previously allocated cluster,
1866		 * then we don't need to reserve it again. However we still need
1867		 * to reserve metadata for every block we're going to write.
1868		 */
1869		if (EXT4_SB(inode->i_sb)->s_cluster_ratio == 1 ||
1870		    !ext4_find_delalloc_cluster(inode, map->m_lblk)) {
1871			ret = ext4_da_reserve_space(inode);
1872			if (ret) {
1873				/* not enough space to reserve */
1874				retval = ret;
1875				goto out_unlock;
1876			}
1877		}
1878
1879		ret = ext4_es_insert_extent(inode, map->m_lblk, map->m_len,
1880					    ~0, EXTENT_STATUS_DELAYED);
1881		if (ret) {
1882			retval = ret;
1883			goto out_unlock;
1884		}
1885
1886		map_bh(bh, inode->i_sb, invalid_block);
1887		set_buffer_new(bh);
1888		set_buffer_delay(bh);
1889	} else if (retval > 0) {
1890		int ret;
1891		unsigned int status;
1892
1893		if (unlikely(retval != map->m_len)) {
1894			ext4_warning(inode->i_sb,
1895				     "ES len assertion failed for inode "
1896				     "%lu: retval %d != map->m_len %d",
1897				     inode->i_ino, retval, map->m_len);
1898			WARN_ON(1);
1899		}
1900
1901		status = map->m_flags & EXT4_MAP_UNWRITTEN ?
1902				EXTENT_STATUS_UNWRITTEN : EXTENT_STATUS_WRITTEN;
1903		ret = ext4_es_insert_extent(inode, map->m_lblk, map->m_len,
1904					    map->m_pblk, status);
1905		if (ret != 0)
1906			retval = ret;
1907	}
1908
1909out_unlock:
1910	up_read((&EXT4_I(inode)->i_data_sem));
1911
1912	return retval;
1913}
1914
1915/*
1916 * This is a special get_block_t callback which is used by
1917 * ext4_da_write_begin().  It will either return mapped block or
1918 * reserve space for a single block.
1919 *
1920 * For delayed buffer_head we have BH_Mapped, BH_New, BH_Delay set.
1921 * We also have b_blocknr = -1 and b_bdev initialized properly
1922 *
1923 * For unwritten buffer_head we have BH_Mapped, BH_New, BH_Unwritten set.
1924 * We also have b_blocknr = physicalblock mapping unwritten extent and b_bdev
1925 * initialized properly.
1926 */
1927int ext4_da_get_block_prep(struct inode *inode, sector_t iblock,
1928			   struct buffer_head *bh, int create)
1929{
1930	struct ext4_map_blocks map;
1931	int ret = 0;
1932
1933	BUG_ON(create == 0);
1934	BUG_ON(bh->b_size != inode->i_sb->s_blocksize);
1935
1936	map.m_lblk = iblock;
1937	map.m_len = 1;
1938
1939	/*
1940	 * first, we need to know whether the block is allocated already
1941	 * preallocated blocks are unmapped but should treated
1942	 * the same as allocated blocks.
1943	 */
1944	ret = ext4_da_map_blocks(inode, iblock, &map, bh);
1945	if (ret <= 0)
1946		return ret;
1947
1948	map_bh(bh, inode->i_sb, map.m_pblk);
1949	ext4_update_bh_state(bh, map.m_flags);
1950
1951	if (buffer_unwritten(bh)) {
1952		/* A delayed write to unwritten bh should be marked
1953		 * new and mapped.  Mapped ensures that we don't do
1954		 * get_block multiple times when we write to the same
1955		 * offset and new ensures that we do proper zero out
1956		 * for partial write.
1957		 */
1958		set_buffer_new(bh);
1959		set_buffer_mapped(bh);
1960	}
1961	return 0;
1962}
1963
1964static int bget_one(handle_t *handle, struct buffer_head *bh)
1965{
1966	get_bh(bh);
1967	return 0;
1968}
1969
1970static int bput_one(handle_t *handle, struct buffer_head *bh)
1971{
1972	put_bh(bh);
1973	return 0;
1974}
1975
1976static int __ext4_journalled_writepage(struct page *page,
1977				       unsigned int len)
1978{
1979	struct address_space *mapping = page->mapping;
1980	struct inode *inode = mapping->host;
1981	struct buffer_head *page_bufs = NULL;
1982	handle_t *handle = NULL;
1983	int ret = 0, err = 0;
1984	int inline_data = ext4_has_inline_data(inode);
1985	struct buffer_head *inode_bh = NULL;
1986
1987	ClearPageChecked(page);
1988
1989	if (inline_data) {
1990		BUG_ON(page->index != 0);
1991		BUG_ON(len > ext4_get_max_inline_size(inode));
1992		inode_bh = ext4_journalled_write_inline_data(inode, len, page);
1993		if (inode_bh == NULL)
1994			goto out;
1995	} else {
1996		page_bufs = page_buffers(page);
1997		if (!page_bufs) {
1998			BUG();
1999			goto out;
2000		}
2001		ext4_walk_page_buffers(handle, page_bufs, 0, len,
2002				       NULL, bget_one);
2003	}
2004	/*
2005	 * We need to release the page lock before we start the
2006	 * journal, so grab a reference so the page won't disappear
2007	 * out from under us.
2008	 */
2009	get_page(page);
2010	unlock_page(page);
2011
2012	handle = ext4_journal_start(inode, EXT4_HT_WRITE_PAGE,
2013				    ext4_writepage_trans_blocks(inode));
2014	if (IS_ERR(handle)) {
2015		ret = PTR_ERR(handle);
2016		put_page(page);
2017		goto out_no_pagelock;
2018	}
2019	BUG_ON(!ext4_handle_valid(handle));
2020
2021	lock_page(page);
2022	put_page(page);
2023	if (page->mapping != mapping) {
2024		/* The page got truncated from under us */
2025		ext4_journal_stop(handle);
2026		ret = 0;
2027		goto out;
2028	}
2029
2030	if (inline_data) {
2031		BUFFER_TRACE(inode_bh, "get write access");
2032		ret = ext4_journal_get_write_access(handle, inode_bh);
2033
2034		err = ext4_handle_dirty_metadata(handle, inode, inode_bh);
2035
2036	} else {
2037		ret = ext4_walk_page_buffers(handle, page_bufs, 0, len, NULL,
2038					     do_journal_get_write_access);
2039
2040		err = ext4_walk_page_buffers(handle, page_bufs, 0, len, NULL,
2041					     write_end_fn);
2042	}
2043	if (ret == 0)
2044		ret = err;
 
 
 
2045	EXT4_I(inode)->i_datasync_tid = handle->h_transaction->t_tid;
2046	err = ext4_journal_stop(handle);
2047	if (!ret)
2048		ret = err;
2049
2050	if (!ext4_has_inline_data(inode))
2051		ext4_walk_page_buffers(NULL, page_bufs, 0, len,
2052				       NULL, bput_one);
2053	ext4_set_inode_state(inode, EXT4_STATE_JDATA);
2054out:
2055	unlock_page(page);
2056out_no_pagelock:
 
 
 
2057	brelse(inode_bh);
2058	return ret;
2059}
2060
2061/*
2062 * Note that we don't need to start a transaction unless we're journaling data
2063 * because we should have holes filled from ext4_page_mkwrite(). We even don't
2064 * need to file the inode to the transaction's list in ordered mode because if
2065 * we are writing back data added by write(), the inode is already there and if
2066 * we are writing back data modified via mmap(), no one guarantees in which
2067 * transaction the data will hit the disk. In case we are journaling data, we
2068 * cannot start transaction directly because transaction start ranks above page
2069 * lock so we have to do some magic.
2070 *
2071 * This function can get called via...
2072 *   - ext4_writepages after taking page lock (have journal handle)
2073 *   - journal_submit_inode_data_buffers (no journal handle)
2074 *   - shrink_page_list via the kswapd/direct reclaim (no journal handle)
2075 *   - grab_page_cache when doing write_begin (have journal handle)
2076 *
2077 * We don't do any block allocation in this function. If we have page with
2078 * multiple blocks we need to write those buffer_heads that are mapped. This
2079 * is important for mmaped based write. So if we do with blocksize 1K
2080 * truncate(f, 1024);
2081 * a = mmap(f, 0, 4096);
2082 * a[0] = 'a';
2083 * truncate(f, 4096);
2084 * we have in the page first buffer_head mapped via page_mkwrite call back
2085 * but other buffer_heads would be unmapped but dirty (dirty done via the
2086 * do_wp_page). So writepage should write the first block. If we modify
2087 * the mmap area beyond 1024 we will again get a page_fault and the
2088 * page_mkwrite callback will do the block allocation and mark the
2089 * buffer_heads mapped.
2090 *
2091 * We redirty the page if we have any buffer_heads that is either delay or
2092 * unwritten in the page.
2093 *
2094 * We can get recursively called as show below.
2095 *
2096 *	ext4_writepage() -> kmalloc() -> __alloc_pages() -> page_launder() ->
2097 *		ext4_writepage()
2098 *
2099 * But since we don't do any block allocation we should not deadlock.
2100 * Page also have the dirty flag cleared so we don't get recurive page_lock.
2101 */
2102static int ext4_writepage(struct page *page,
2103			  struct writeback_control *wbc)
2104{
2105	int ret = 0;
2106	loff_t size;
2107	unsigned int len;
2108	struct buffer_head *page_bufs = NULL;
2109	struct inode *inode = page->mapping->host;
2110	struct ext4_io_submit io_submit;
2111	bool keep_towrite = false;
2112
2113	if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb)))) {
2114		ext4_invalidatepage(page, 0, PAGE_SIZE);
2115		unlock_page(page);
2116		return -EIO;
2117	}
2118
2119	trace_ext4_writepage(page);
2120	size = i_size_read(inode);
2121	if (page->index == size >> PAGE_SHIFT)
 
2122		len = size & ~PAGE_MASK;
2123	else
2124		len = PAGE_SIZE;
2125
2126	page_bufs = page_buffers(page);
2127	/*
2128	 * We cannot do block allocation or other extent handling in this
2129	 * function. If there are buffers needing that, we have to redirty
2130	 * the page. But we may reach here when we do a journal commit via
2131	 * journal_submit_inode_data_buffers() and in that case we must write
2132	 * allocated buffers to achieve data=ordered mode guarantees.
2133	 *
2134	 * Also, if there is only one buffer per page (the fs block
2135	 * size == the page size), if one buffer needs block
2136	 * allocation or needs to modify the extent tree to clear the
2137	 * unwritten flag, we know that the page can't be written at
2138	 * all, so we might as well refuse the write immediately.
2139	 * Unfortunately if the block size != page size, we can't as
2140	 * easily detect this case using ext4_walk_page_buffers(), but
2141	 * for the extremely common case, this is an optimization that
2142	 * skips a useless round trip through ext4_bio_write_page().
2143	 */
2144	if (ext4_walk_page_buffers(NULL, page_bufs, 0, len, NULL,
2145				   ext4_bh_delay_or_unwritten)) {
2146		redirty_page_for_writepage(wbc, page);
2147		if ((current->flags & PF_MEMALLOC) ||
2148		    (inode->i_sb->s_blocksize == PAGE_SIZE)) {
2149			/*
2150			 * For memory cleaning there's no point in writing only
2151			 * some buffers. So just bail out. Warn if we came here
2152			 * from direct reclaim.
2153			 */
2154			WARN_ON_ONCE((current->flags & (PF_MEMALLOC|PF_KSWAPD))
2155							== PF_MEMALLOC);
2156			unlock_page(page);
2157			return 0;
2158		}
2159		keep_towrite = true;
2160	}
2161
2162	if (PageChecked(page) && ext4_should_journal_data(inode))
2163		/*
2164		 * It's mmapped pagecache.  Add buffers and journal it.  There
2165		 * doesn't seem much point in redirtying the page here.
2166		 */
2167		return __ext4_journalled_writepage(page, len);
2168
2169	ext4_io_submit_init(&io_submit, wbc);
2170	io_submit.io_end = ext4_init_io_end(inode, GFP_NOFS);
2171	if (!io_submit.io_end) {
2172		redirty_page_for_writepage(wbc, page);
2173		unlock_page(page);
2174		return -ENOMEM;
2175	}
2176	ret = ext4_bio_write_page(&io_submit, page, len, wbc, keep_towrite);
2177	ext4_io_submit(&io_submit);
2178	/* Drop io_end reference we got from init */
2179	ext4_put_io_end_defer(io_submit.io_end);
2180	return ret;
2181}
2182
2183static int mpage_submit_page(struct mpage_da_data *mpd, struct page *page)
2184{
2185	int len;
2186	loff_t size;
2187	int err;
2188
2189	BUG_ON(page->index != mpd->first_page);
2190	clear_page_dirty_for_io(page);
2191	/*
2192	 * We have to be very careful here!  Nothing protects writeback path
2193	 * against i_size changes and the page can be writeably mapped into
2194	 * page tables. So an application can be growing i_size and writing
2195	 * data through mmap while writeback runs. clear_page_dirty_for_io()
2196	 * write-protects our page in page tables and the page cannot get
2197	 * written to again until we release page lock. So only after
2198	 * clear_page_dirty_for_io() we are safe to sample i_size for
2199	 * ext4_bio_write_page() to zero-out tail of the written page. We rely
2200	 * on the barrier provided by TestClearPageDirty in
2201	 * clear_page_dirty_for_io() to make sure i_size is really sampled only
2202	 * after page tables are updated.
2203	 */
2204	size = i_size_read(mpd->inode);
2205	if (page->index == size >> PAGE_SHIFT)
 
2206		len = size & ~PAGE_MASK;
2207	else
2208		len = PAGE_SIZE;
2209	err = ext4_bio_write_page(&mpd->io_submit, page, len, mpd->wbc, false);
2210	if (!err)
2211		mpd->wbc->nr_to_write--;
2212	mpd->first_page++;
2213
2214	return err;
2215}
2216
2217#define BH_FLAGS ((1 << BH_Unwritten) | (1 << BH_Delay))
2218
2219/*
2220 * mballoc gives us at most this number of blocks...
2221 * XXX: That seems to be only a limitation of ext4_mb_normalize_request().
2222 * The rest of mballoc seems to handle chunks up to full group size.
2223 */
2224#define MAX_WRITEPAGES_EXTENT_LEN 2048
2225
2226/*
2227 * mpage_add_bh_to_extent - try to add bh to extent of blocks to map
2228 *
2229 * @mpd - extent of blocks
2230 * @lblk - logical number of the block in the file
2231 * @bh - buffer head we want to add to the extent
2232 *
2233 * The function is used to collect contig. blocks in the same state. If the
2234 * buffer doesn't require mapping for writeback and we haven't started the
2235 * extent of buffers to map yet, the function returns 'true' immediately - the
2236 * caller can write the buffer right away. Otherwise the function returns true
2237 * if the block has been added to the extent, false if the block couldn't be
2238 * added.
2239 */
2240static bool mpage_add_bh_to_extent(struct mpage_da_data *mpd, ext4_lblk_t lblk,
2241				   struct buffer_head *bh)
2242{
2243	struct ext4_map_blocks *map = &mpd->map;
2244
2245	/* Buffer that doesn't need mapping for writeback? */
2246	if (!buffer_dirty(bh) || !buffer_mapped(bh) ||
2247	    (!buffer_delay(bh) && !buffer_unwritten(bh))) {
2248		/* So far no extent to map => we write the buffer right away */
2249		if (map->m_len == 0)
2250			return true;
2251		return false;
2252	}
2253
2254	/* First block in the extent? */
2255	if (map->m_len == 0) {
2256		/* We cannot map unless handle is started... */
2257		if (!mpd->do_map)
2258			return false;
2259		map->m_lblk = lblk;
2260		map->m_len = 1;
2261		map->m_flags = bh->b_state & BH_FLAGS;
2262		return true;
2263	}
2264
2265	/* Don't go larger than mballoc is willing to allocate */
2266	if (map->m_len >= MAX_WRITEPAGES_EXTENT_LEN)
2267		return false;
2268
2269	/* Can we merge the block to our big extent? */
2270	if (lblk == map->m_lblk + map->m_len &&
2271	    (bh->b_state & BH_FLAGS) == map->m_flags) {
2272		map->m_len++;
2273		return true;
2274	}
2275	return false;
2276}
2277
2278/*
2279 * mpage_process_page_bufs - submit page buffers for IO or add them to extent
2280 *
2281 * @mpd - extent of blocks for mapping
2282 * @head - the first buffer in the page
2283 * @bh - buffer we should start processing from
2284 * @lblk - logical number of the block in the file corresponding to @bh
2285 *
2286 * Walk through page buffers from @bh upto @head (exclusive) and either submit
2287 * the page for IO if all buffers in this page were mapped and there's no
2288 * accumulated extent of buffers to map or add buffers in the page to the
2289 * extent of buffers to map. The function returns 1 if the caller can continue
2290 * by processing the next page, 0 if it should stop adding buffers to the
2291 * extent to map because we cannot extend it anymore. It can also return value
2292 * < 0 in case of error during IO submission.
2293 */
2294static int mpage_process_page_bufs(struct mpage_da_data *mpd,
2295				   struct buffer_head *head,
2296				   struct buffer_head *bh,
2297				   ext4_lblk_t lblk)
2298{
2299	struct inode *inode = mpd->inode;
2300	int err;
2301	ext4_lblk_t blocks = (i_size_read(inode) + i_blocksize(inode) - 1)
2302							>> inode->i_blkbits;
2303
 
 
 
2304	do {
2305		BUG_ON(buffer_locked(bh));
2306
2307		if (lblk >= blocks || !mpage_add_bh_to_extent(mpd, lblk, bh)) {
2308			/* Found extent to map? */
2309			if (mpd->map.m_len)
2310				return 0;
2311			/* Buffer needs mapping and handle is not started? */
2312			if (!mpd->do_map)
2313				return 0;
2314			/* Everything mapped so far and we hit EOF */
2315			break;
2316		}
2317	} while (lblk++, (bh = bh->b_this_page) != head);
2318	/* So far everything mapped? Submit the page for IO. */
2319	if (mpd->map.m_len == 0) {
2320		err = mpage_submit_page(mpd, head->b_page);
2321		if (err < 0)
2322			return err;
2323	}
2324	return lblk < blocks;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2325}
2326
2327/*
2328 * mpage_map_buffers - update buffers corresponding to changed extent and
2329 *		       submit fully mapped pages for IO
2330 *
2331 * @mpd - description of extent to map, on return next extent to map
2332 *
2333 * Scan buffers corresponding to changed extent (we expect corresponding pages
2334 * to be already locked) and update buffer state according to new extent state.
2335 * We map delalloc buffers to their physical location, clear unwritten bits,
2336 * and mark buffers as uninit when we perform writes to unwritten extents
2337 * and do extent conversion after IO is finished. If the last page is not fully
2338 * mapped, we update @map to the next extent in the last page that needs
2339 * mapping. Otherwise we submit the page for IO.
2340 */
2341static int mpage_map_and_submit_buffers(struct mpage_da_data *mpd)
2342{
2343	struct pagevec pvec;
2344	int nr_pages, i;
2345	struct inode *inode = mpd->inode;
2346	struct buffer_head *head, *bh;
2347	int bpp_bits = PAGE_SHIFT - inode->i_blkbits;
2348	pgoff_t start, end;
2349	ext4_lblk_t lblk;
2350	sector_t pblock;
2351	int err;
 
2352
2353	start = mpd->map.m_lblk >> bpp_bits;
2354	end = (mpd->map.m_lblk + mpd->map.m_len - 1) >> bpp_bits;
2355	lblk = start << bpp_bits;
2356	pblock = mpd->map.m_pblk;
2357
2358	pagevec_init(&pvec);
2359	while (start <= end) {
2360		nr_pages = pagevec_lookup_range(&pvec, inode->i_mapping,
2361						&start, end);
2362		if (nr_pages == 0)
2363			break;
2364		for (i = 0; i < nr_pages; i++) {
2365			struct page *page = pvec.pages[i];
2366
2367			bh = head = page_buffers(page);
2368			do {
2369				if (lblk < mpd->map.m_lblk)
2370					continue;
2371				if (lblk >= mpd->map.m_lblk + mpd->map.m_len) {
2372					/*
2373					 * Buffer after end of mapped extent.
2374					 * Find next buffer in the page to map.
2375					 */
2376					mpd->map.m_len = 0;
2377					mpd->map.m_flags = 0;
2378					/*
2379					 * FIXME: If dioread_nolock supports
2380					 * blocksize < pagesize, we need to make
2381					 * sure we add size mapped so far to
2382					 * io_end->size as the following call
2383					 * can submit the page for IO.
2384					 */
2385					err = mpage_process_page_bufs(mpd, head,
2386								      bh, lblk);
2387					pagevec_release(&pvec);
2388					if (err > 0)
2389						err = 0;
2390					return err;
2391				}
2392				if (buffer_delay(bh)) {
2393					clear_buffer_delay(bh);
2394					bh->b_blocknr = pblock++;
2395				}
2396				clear_buffer_unwritten(bh);
2397			} while (lblk++, (bh = bh->b_this_page) != head);
2398
2399			/*
2400			 * FIXME: This is going to break if dioread_nolock
2401			 * supports blocksize < pagesize as we will try to
2402			 * convert potentially unmapped parts of inode.
2403			 */
2404			mpd->io_submit.io_end->size += PAGE_SIZE;
 
2405			/* Page fully mapped - let IO run! */
2406			err = mpage_submit_page(mpd, page);
2407			if (err < 0) {
2408				pagevec_release(&pvec);
2409				return err;
2410			}
2411		}
2412		pagevec_release(&pvec);
2413	}
2414	/* Extent fully mapped and matches with page boundary. We are done. */
2415	mpd->map.m_len = 0;
2416	mpd->map.m_flags = 0;
2417	return 0;
 
 
 
2418}
2419
2420static int mpage_map_one_extent(handle_t *handle, struct mpage_da_data *mpd)
2421{
2422	struct inode *inode = mpd->inode;
2423	struct ext4_map_blocks *map = &mpd->map;
2424	int get_blocks_flags;
2425	int err, dioread_nolock;
2426
2427	trace_ext4_da_write_pages_extent(inode, map);
2428	/*
2429	 * Call ext4_map_blocks() to allocate any delayed allocation blocks, or
2430	 * to convert an unwritten extent to be initialized (in the case
2431	 * where we have written into one or more preallocated blocks).  It is
2432	 * possible that we're going to need more metadata blocks than
2433	 * previously reserved. However we must not fail because we're in
2434	 * writeback and there is nothing we can do about it so it might result
2435	 * in data loss.  So use reserved blocks to allocate metadata if
2436	 * possible.
2437	 *
2438	 * We pass in the magic EXT4_GET_BLOCKS_DELALLOC_RESERVE if
2439	 * the blocks in question are delalloc blocks.  This indicates
2440	 * that the blocks and quotas has already been checked when
2441	 * the data was copied into the page cache.
2442	 */
2443	get_blocks_flags = EXT4_GET_BLOCKS_CREATE |
2444			   EXT4_GET_BLOCKS_METADATA_NOFAIL |
2445			   EXT4_GET_BLOCKS_IO_SUBMIT;
2446	dioread_nolock = ext4_should_dioread_nolock(inode);
2447	if (dioread_nolock)
2448		get_blocks_flags |= EXT4_GET_BLOCKS_IO_CREATE_EXT;
2449	if (map->m_flags & (1 << BH_Delay))
2450		get_blocks_flags |= EXT4_GET_BLOCKS_DELALLOC_RESERVE;
2451
2452	err = ext4_map_blocks(handle, inode, map, get_blocks_flags);
2453	if (err < 0)
2454		return err;
2455	if (dioread_nolock && (map->m_flags & EXT4_MAP_UNWRITTEN)) {
2456		if (!mpd->io_submit.io_end->handle &&
2457		    ext4_handle_valid(handle)) {
2458			mpd->io_submit.io_end->handle = handle->h_rsv_handle;
2459			handle->h_rsv_handle = NULL;
2460		}
2461		ext4_set_io_unwritten_flag(inode, mpd->io_submit.io_end);
2462	}
2463
2464	BUG_ON(map->m_len == 0);
2465	if (map->m_flags & EXT4_MAP_NEW) {
2466		clean_bdev_aliases(inode->i_sb->s_bdev, map->m_pblk,
2467				   map->m_len);
2468	}
2469	return 0;
2470}
2471
2472/*
2473 * mpage_map_and_submit_extent - map extent starting at mpd->lblk of length
2474 *				 mpd->len and submit pages underlying it for IO
2475 *
2476 * @handle - handle for journal operations
2477 * @mpd - extent to map
2478 * @give_up_on_write - we set this to true iff there is a fatal error and there
2479 *                     is no hope of writing the data. The caller should discard
2480 *                     dirty pages to avoid infinite loops.
2481 *
2482 * The function maps extent starting at mpd->lblk of length mpd->len. If it is
2483 * delayed, blocks are allocated, if it is unwritten, we may need to convert
2484 * them to initialized or split the described range from larger unwritten
2485 * extent. Note that we need not map all the described range since allocation
2486 * can return less blocks or the range is covered by more unwritten extents. We
2487 * cannot map more because we are limited by reserved transaction credits. On
2488 * the other hand we always make sure that the last touched page is fully
2489 * mapped so that it can be written out (and thus forward progress is
2490 * guaranteed). After mapping we submit all mapped pages for IO.
2491 */
2492static int mpage_map_and_submit_extent(handle_t *handle,
2493				       struct mpage_da_data *mpd,
2494				       bool *give_up_on_write)
2495{
2496	struct inode *inode = mpd->inode;
2497	struct ext4_map_blocks *map = &mpd->map;
2498	int err;
2499	loff_t disksize;
2500	int progress = 0;
 
 
2501
2502	mpd->io_submit.io_end->offset =
2503				((loff_t)map->m_lblk) << inode->i_blkbits;
 
 
2504	do {
2505		err = mpage_map_one_extent(handle, mpd);
2506		if (err < 0) {
2507			struct super_block *sb = inode->i_sb;
2508
2509			if (ext4_forced_shutdown(EXT4_SB(sb)) ||
2510			    EXT4_SB(sb)->s_mount_flags & EXT4_MF_FS_ABORTED)
2511				goto invalidate_dirty_pages;
2512			/*
2513			 * Let the uper layers retry transient errors.
2514			 * In the case of ENOSPC, if ext4_count_free_blocks()
2515			 * is non-zero, a commit should free up blocks.
2516			 */
2517			if ((err == -ENOMEM) ||
2518			    (err == -ENOSPC && ext4_count_free_clusters(sb))) {
2519				if (progress)
2520					goto update_disksize;
2521				return err;
2522			}
2523			ext4_msg(sb, KERN_CRIT,
2524				 "Delayed block allocation failed for "
2525				 "inode %lu at logical offset %llu with"
2526				 " max blocks %u with error %d",
2527				 inode->i_ino,
2528				 (unsigned long long)map->m_lblk,
2529				 (unsigned)map->m_len, -err);
2530			ext4_msg(sb, KERN_CRIT,
2531				 "This should not happen!! Data will "
2532				 "be lost\n");
2533			if (err == -ENOSPC)
2534				ext4_print_free_blocks(inode);
2535		invalidate_dirty_pages:
2536			*give_up_on_write = true;
2537			return err;
2538		}
2539		progress = 1;
2540		/*
2541		 * Update buffer state, submit mapped pages, and get us new
2542		 * extent to map
2543		 */
2544		err = mpage_map_and_submit_buffers(mpd);
2545		if (err < 0)
2546			goto update_disksize;
2547	} while (map->m_len);
2548
2549update_disksize:
2550	/*
2551	 * Update on-disk size after IO is submitted.  Races with
2552	 * truncate are avoided by checking i_size under i_data_sem.
2553	 */
2554	disksize = ((loff_t)mpd->first_page) << PAGE_SHIFT;
2555	if (disksize > EXT4_I(inode)->i_disksize) {
2556		int err2;
2557		loff_t i_size;
2558
2559		down_write(&EXT4_I(inode)->i_data_sem);
2560		i_size = i_size_read(inode);
2561		if (disksize > i_size)
2562			disksize = i_size;
2563		if (disksize > EXT4_I(inode)->i_disksize)
2564			EXT4_I(inode)->i_disksize = disksize;
2565		up_write(&EXT4_I(inode)->i_data_sem);
2566		err2 = ext4_mark_inode_dirty(handle, inode);
2567		if (err2)
2568			ext4_error(inode->i_sb,
2569				   "Failed to mark inode %lu dirty",
2570				   inode->i_ino);
 
2571		if (!err)
2572			err = err2;
2573	}
2574	return err;
2575}
2576
2577/*
2578 * Calculate the total number of credits to reserve for one writepages
2579 * iteration. This is called from ext4_writepages(). We map an extent of
2580 * up to MAX_WRITEPAGES_EXTENT_LEN blocks and then we go on and finish mapping
2581 * the last partial page. So in total we can map MAX_WRITEPAGES_EXTENT_LEN +
2582 * bpp - 1 blocks in bpp different extents.
2583 */
2584static int ext4_da_writepages_trans_blocks(struct inode *inode)
2585{
2586	int bpp = ext4_journal_blocks_per_page(inode);
2587
2588	return ext4_meta_trans_blocks(inode,
2589				MAX_WRITEPAGES_EXTENT_LEN + bpp - 1, bpp);
2590}
2591
2592/*
2593 * mpage_prepare_extent_to_map - find & lock contiguous range of dirty pages
2594 * 				 and underlying extent to map
2595 *
2596 * @mpd - where to look for pages
2597 *
2598 * Walk dirty pages in the mapping. If they are fully mapped, submit them for
2599 * IO immediately. When we find a page which isn't mapped we start accumulating
2600 * extent of buffers underlying these pages that needs mapping (formed by
2601 * either delayed or unwritten buffers). We also lock the pages containing
2602 * these buffers. The extent found is returned in @mpd structure (starting at
2603 * mpd->lblk with length mpd->len blocks).
2604 *
2605 * Note that this function can attach bios to one io_end structure which are
2606 * neither logically nor physically contiguous. Although it may seem as an
2607 * unnecessary complication, it is actually inevitable in blocksize < pagesize
2608 * case as we need to track IO to all buffers underlying a page in one io_end.
2609 */
2610static int mpage_prepare_extent_to_map(struct mpage_da_data *mpd)
2611{
2612	struct address_space *mapping = mpd->inode->i_mapping;
2613	struct pagevec pvec;
2614	unsigned int nr_pages;
2615	long left = mpd->wbc->nr_to_write;
2616	pgoff_t index = mpd->first_page;
2617	pgoff_t end = mpd->last_page;
2618	int tag;
2619	int i, err = 0;
2620	int blkbits = mpd->inode->i_blkbits;
2621	ext4_lblk_t lblk;
2622	struct buffer_head *head;
2623
2624	if (mpd->wbc->sync_mode == WB_SYNC_ALL || mpd->wbc->tagged_writepages)
2625		tag = PAGECACHE_TAG_TOWRITE;
2626	else
2627		tag = PAGECACHE_TAG_DIRTY;
2628
2629	pagevec_init(&pvec);
2630	mpd->map.m_len = 0;
2631	mpd->next_page = index;
2632	while (index <= end) {
2633		nr_pages = pagevec_lookup_range_tag(&pvec, mapping, &index, end,
2634				tag);
2635		if (nr_pages == 0)
2636			goto out;
2637
2638		for (i = 0; i < nr_pages; i++) {
2639			struct page *page = pvec.pages[i];
2640
2641			/*
2642			 * Accumulated enough dirty pages? This doesn't apply
2643			 * to WB_SYNC_ALL mode. For integrity sync we have to
2644			 * keep going because someone may be concurrently
2645			 * dirtying pages, and we might have synced a lot of
2646			 * newly appeared dirty pages, but have not synced all
2647			 * of the old dirty pages.
2648			 */
2649			if (mpd->wbc->sync_mode == WB_SYNC_NONE && left <= 0)
2650				goto out;
2651
2652			/* If we can't merge this page, we are done. */
2653			if (mpd->map.m_len > 0 && mpd->next_page != page->index)
2654				goto out;
2655
2656			lock_page(page);
2657			/*
2658			 * If the page is no longer dirty, or its mapping no
2659			 * longer corresponds to inode we are writing (which
2660			 * means it has been truncated or invalidated), or the
2661			 * page is already under writeback and we are not doing
2662			 * a data integrity writeback, skip the page
2663			 */
2664			if (!PageDirty(page) ||
2665			    (PageWriteback(page) &&
2666			     (mpd->wbc->sync_mode == WB_SYNC_NONE)) ||
2667			    unlikely(page->mapping != mapping)) {
2668				unlock_page(page);
2669				continue;
2670			}
2671
2672			wait_on_page_writeback(page);
2673			BUG_ON(PageWriteback(page));
2674
2675			if (mpd->map.m_len == 0)
2676				mpd->first_page = page->index;
2677			mpd->next_page = page->index + 1;
2678			/* Add all dirty buffers to mpd */
2679			lblk = ((ext4_lblk_t)page->index) <<
2680				(PAGE_SHIFT - blkbits);
2681			head = page_buffers(page);
2682			err = mpage_process_page_bufs(mpd, head, head, lblk);
2683			if (err <= 0)
2684				goto out;
2685			err = 0;
2686			left--;
2687		}
2688		pagevec_release(&pvec);
2689		cond_resched();
2690	}
 
2691	return 0;
2692out:
2693	pagevec_release(&pvec);
2694	return err;
2695}
2696
2697static int ext4_writepages(struct address_space *mapping,
2698			   struct writeback_control *wbc)
2699{
2700	pgoff_t	writeback_index = 0;
2701	long nr_to_write = wbc->nr_to_write;
2702	int range_whole = 0;
2703	int cycled = 1;
2704	handle_t *handle = NULL;
2705	struct mpage_da_data mpd;
2706	struct inode *inode = mapping->host;
2707	int needed_blocks, rsv_blocks = 0, ret = 0;
2708	struct ext4_sb_info *sbi = EXT4_SB(mapping->host->i_sb);
2709	bool done;
2710	struct blk_plug plug;
2711	bool give_up_on_write = false;
2712
2713	if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb))))
2714		return -EIO;
2715
2716	percpu_down_read(&sbi->s_journal_flag_rwsem);
2717	trace_ext4_writepages(inode, wbc);
2718
2719	/*
2720	 * No pages to write? This is mainly a kludge to avoid starting
2721	 * a transaction for special inodes like journal inode on last iput()
2722	 * because that could violate lock ordering on umount
2723	 */
2724	if (!mapping->nrpages || !mapping_tagged(mapping, PAGECACHE_TAG_DIRTY))
2725		goto out_writepages;
2726
2727	if (ext4_should_journal_data(inode)) {
2728		ret = generic_writepages(mapping, wbc);
2729		goto out_writepages;
2730	}
2731
2732	/*
2733	 * If the filesystem has aborted, it is read-only, so return
2734	 * right away instead of dumping stack traces later on that
2735	 * will obscure the real source of the problem.  We test
2736	 * EXT4_MF_FS_ABORTED instead of sb->s_flag's SB_RDONLY because
2737	 * the latter could be true if the filesystem is mounted
2738	 * read-only, and in that case, ext4_writepages should
2739	 * *never* be called, so if that ever happens, we would want
2740	 * the stack trace.
2741	 */
2742	if (unlikely(ext4_forced_shutdown(EXT4_SB(mapping->host->i_sb)) ||
2743		     sbi->s_mount_flags & EXT4_MF_FS_ABORTED)) {
2744		ret = -EROFS;
2745		goto out_writepages;
2746	}
2747
2748	if (ext4_should_dioread_nolock(inode)) {
2749		/*
2750		 * We may need to convert up to one extent per block in
2751		 * the page and we may dirty the inode.
2752		 */
2753		rsv_blocks = 1 + (PAGE_SIZE >> inode->i_blkbits);
2754	}
2755
2756	/*
2757	 * If we have inline data and arrive here, it means that
2758	 * we will soon create the block for the 1st page, so
2759	 * we'd better clear the inline data here.
2760	 */
2761	if (ext4_has_inline_data(inode)) {
2762		/* Just inode will be modified... */
2763		handle = ext4_journal_start(inode, EXT4_HT_INODE, 1);
2764		if (IS_ERR(handle)) {
2765			ret = PTR_ERR(handle);
2766			goto out_writepages;
2767		}
2768		BUG_ON(ext4_test_inode_state(inode,
2769				EXT4_STATE_MAY_INLINE_DATA));
2770		ext4_destroy_inline_data(handle, inode);
2771		ext4_journal_stop(handle);
2772	}
2773
 
 
 
 
 
 
 
 
 
2774	if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX)
2775		range_whole = 1;
2776
2777	if (wbc->range_cyclic) {
2778		writeback_index = mapping->writeback_index;
2779		if (writeback_index)
2780			cycled = 0;
2781		mpd.first_page = writeback_index;
2782		mpd.last_page = -1;
2783	} else {
2784		mpd.first_page = wbc->range_start >> PAGE_SHIFT;
2785		mpd.last_page = wbc->range_end >> PAGE_SHIFT;
2786	}
2787
2788	mpd.inode = inode;
2789	mpd.wbc = wbc;
2790	ext4_io_submit_init(&mpd.io_submit, wbc);
2791retry:
2792	if (wbc->sync_mode == WB_SYNC_ALL || wbc->tagged_writepages)
2793		tag_pages_for_writeback(mapping, mpd.first_page, mpd.last_page);
2794	done = false;
2795	blk_start_plug(&plug);
2796
2797	/*
2798	 * First writeback pages that don't need mapping - we can avoid
2799	 * starting a transaction unnecessarily and also avoid being blocked
2800	 * in the block layer on device congestion while having transaction
2801	 * started.
2802	 */
2803	mpd.do_map = 0;
 
2804	mpd.io_submit.io_end = ext4_init_io_end(inode, GFP_KERNEL);
2805	if (!mpd.io_submit.io_end) {
2806		ret = -ENOMEM;
2807		goto unplug;
2808	}
2809	ret = mpage_prepare_extent_to_map(&mpd);
 
 
2810	/* Submit prepared bio */
2811	ext4_io_submit(&mpd.io_submit);
2812	ext4_put_io_end_defer(mpd.io_submit.io_end);
2813	mpd.io_submit.io_end = NULL;
2814	/* Unlock pages we didn't use */
2815	mpage_release_unused_pages(&mpd, false);
2816	if (ret < 0)
2817		goto unplug;
2818
2819	while (!done && mpd.first_page <= mpd.last_page) {
2820		/* For each extent of pages we use new io_end */
2821		mpd.io_submit.io_end = ext4_init_io_end(inode, GFP_KERNEL);
2822		if (!mpd.io_submit.io_end) {
2823			ret = -ENOMEM;
2824			break;
2825		}
2826
2827		/*
2828		 * We have two constraints: We find one extent to map and we
2829		 * must always write out whole page (makes a difference when
2830		 * blocksize < pagesize) so that we don't block on IO when we
2831		 * try to write out the rest of the page. Journalled mode is
2832		 * not supported by delalloc.
2833		 */
2834		BUG_ON(ext4_should_journal_data(inode));
2835		needed_blocks = ext4_da_writepages_trans_blocks(inode);
2836
2837		/* start a new transaction */
2838		handle = ext4_journal_start_with_reserve(inode,
2839				EXT4_HT_WRITE_PAGE, needed_blocks, rsv_blocks);
2840		if (IS_ERR(handle)) {
2841			ret = PTR_ERR(handle);
2842			ext4_msg(inode->i_sb, KERN_CRIT, "%s: jbd2_start: "
2843			       "%ld pages, ino %lu; err %d", __func__,
2844				wbc->nr_to_write, inode->i_ino, ret);
2845			/* Release allocated io_end */
2846			ext4_put_io_end(mpd.io_submit.io_end);
2847			mpd.io_submit.io_end = NULL;
2848			break;
2849		}
2850		mpd.do_map = 1;
2851
2852		trace_ext4_da_write_pages(inode, mpd.first_page, mpd.wbc);
2853		ret = mpage_prepare_extent_to_map(&mpd);
2854		if (!ret) {
2855			if (mpd.map.m_len)
2856				ret = mpage_map_and_submit_extent(handle, &mpd,
2857					&give_up_on_write);
2858			else {
2859				/*
2860				 * We scanned the whole range (or exhausted
2861				 * nr_to_write), submitted what was mapped and
2862				 * didn't find anything needing mapping. We are
2863				 * done.
2864				 */
2865				done = true;
2866			}
2867		}
2868		/*
2869		 * Caution: If the handle is synchronous,
2870		 * ext4_journal_stop() can wait for transaction commit
2871		 * to finish which may depend on writeback of pages to
2872		 * complete or on page lock to be released.  In that
2873		 * case, we have to wait until after after we have
2874		 * submitted all the IO, released page locks we hold,
2875		 * and dropped io_end reference (for extent conversion
2876		 * to be able to complete) before stopping the handle.
2877		 */
2878		if (!ext4_handle_valid(handle) || handle->h_sync == 0) {
2879			ext4_journal_stop(handle);
2880			handle = NULL;
2881			mpd.do_map = 0;
2882		}
2883		/* Submit prepared bio */
2884		ext4_io_submit(&mpd.io_submit);
2885		/* Unlock pages we didn't use */
2886		mpage_release_unused_pages(&mpd, give_up_on_write);
 
 
 
2887		/*
2888		 * Drop our io_end reference we got from init. We have
2889		 * to be careful and use deferred io_end finishing if
2890		 * we are still holding the transaction as we can
2891		 * release the last reference to io_end which may end
2892		 * up doing unwritten extent conversion.
2893		 */
2894		if (handle) {
2895			ext4_put_io_end_defer(mpd.io_submit.io_end);
2896			ext4_journal_stop(handle);
2897		} else
2898			ext4_put_io_end(mpd.io_submit.io_end);
2899		mpd.io_submit.io_end = NULL;
2900
2901		if (ret == -ENOSPC && sbi->s_journal) {
2902			/*
2903			 * Commit the transaction which would
2904			 * free blocks released in the transaction
2905			 * and try again
2906			 */
2907			jbd2_journal_force_commit_nested(sbi->s_journal);
2908			ret = 0;
2909			continue;
2910		}
2911		/* Fatal error - ENOMEM, EIO... */
2912		if (ret)
2913			break;
2914	}
2915unplug:
2916	blk_finish_plug(&plug);
2917	if (!ret && !cycled && wbc->nr_to_write > 0) {
2918		cycled = 1;
2919		mpd.last_page = writeback_index - 1;
2920		mpd.first_page = 0;
2921		goto retry;
2922	}
2923
2924	/* Update index */
2925	if (wbc->range_cyclic || (range_whole && wbc->nr_to_write > 0))
2926		/*
2927		 * Set the writeback_index so that range_cyclic
2928		 * mode will write it back later
2929		 */
2930		mapping->writeback_index = mpd.first_page;
2931
2932out_writepages:
2933	trace_ext4_writepages_result(inode, wbc, ret,
2934				     nr_to_write - wbc->nr_to_write);
2935	percpu_up_read(&sbi->s_journal_flag_rwsem);
2936	return ret;
2937}
2938
2939static int ext4_dax_writepages(struct address_space *mapping,
2940			       struct writeback_control *wbc)
2941{
2942	int ret;
2943	long nr_to_write = wbc->nr_to_write;
2944	struct inode *inode = mapping->host;
2945	struct ext4_sb_info *sbi = EXT4_SB(mapping->host->i_sb);
2946
2947	if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb))))
2948		return -EIO;
2949
2950	percpu_down_read(&sbi->s_journal_flag_rwsem);
2951	trace_ext4_writepages(inode, wbc);
2952
2953	ret = dax_writeback_mapping_range(mapping, inode->i_sb->s_bdev, wbc);
2954	trace_ext4_writepages_result(inode, wbc, ret,
2955				     nr_to_write - wbc->nr_to_write);
2956	percpu_up_read(&sbi->s_journal_flag_rwsem);
2957	return ret;
2958}
2959
2960static int ext4_nonda_switch(struct super_block *sb)
2961{
2962	s64 free_clusters, dirty_clusters;
2963	struct ext4_sb_info *sbi = EXT4_SB(sb);
2964
2965	/*
2966	 * switch to non delalloc mode if we are running low
2967	 * on free block. The free block accounting via percpu
2968	 * counters can get slightly wrong with percpu_counter_batch getting
2969	 * accumulated on each CPU without updating global counters
2970	 * Delalloc need an accurate free block accounting. So switch
2971	 * to non delalloc when we are near to error range.
2972	 */
2973	free_clusters =
2974		percpu_counter_read_positive(&sbi->s_freeclusters_counter);
2975	dirty_clusters =
2976		percpu_counter_read_positive(&sbi->s_dirtyclusters_counter);
2977	/*
2978	 * Start pushing delalloc when 1/2 of free blocks are dirty.
2979	 */
2980	if (dirty_clusters && (free_clusters < 2 * dirty_clusters))
2981		try_to_writeback_inodes_sb(sb, WB_REASON_FS_FREE_SPACE);
2982
2983	if (2 * free_clusters < 3 * dirty_clusters ||
2984	    free_clusters < (dirty_clusters + EXT4_FREECLUSTERS_WATERMARK)) {
2985		/*
2986		 * free block count is less than 150% of dirty blocks
2987		 * or free blocks is less than watermark
2988		 */
2989		return 1;
2990	}
2991	return 0;
2992}
2993
2994/* We always reserve for an inode update; the superblock could be there too */
2995static int ext4_da_write_credits(struct inode *inode, loff_t pos, unsigned len)
2996{
2997	if (likely(ext4_has_feature_large_file(inode->i_sb)))
2998		return 1;
2999
3000	if (pos + len <= 0x7fffffffULL)
3001		return 1;
3002
3003	/* We might need to update the superblock to set LARGE_FILE */
3004	return 2;
3005}
3006
3007static int ext4_da_write_begin(struct file *file, struct address_space *mapping,
3008			       loff_t pos, unsigned len, unsigned flags,
3009			       struct page **pagep, void **fsdata)
3010{
3011	int ret, retries = 0;
3012	struct page *page;
3013	pgoff_t index;
3014	struct inode *inode = mapping->host;
3015	handle_t *handle;
3016
3017	if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb))))
3018		return -EIO;
3019
3020	index = pos >> PAGE_SHIFT;
3021
3022	if (ext4_nonda_switch(inode->i_sb) ||
3023	    S_ISLNK(inode->i_mode)) {
3024		*fsdata = (void *)FALL_BACK_TO_NONDELALLOC;
3025		return ext4_write_begin(file, mapping, pos,
3026					len, flags, pagep, fsdata);
3027	}
3028	*fsdata = (void *)0;
3029	trace_ext4_da_write_begin(inode, pos, len, flags);
3030
3031	if (ext4_test_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA)) {
3032		ret = ext4_da_write_inline_data_begin(mapping, inode,
3033						      pos, len, flags,
3034						      pagep, fsdata);
3035		if (ret < 0)
3036			return ret;
3037		if (ret == 1)
3038			return 0;
3039	}
3040
3041	/*
3042	 * grab_cache_page_write_begin() can take a long time if the
3043	 * system is thrashing due to memory pressure, or if the page
3044	 * is being written back.  So grab it first before we start
3045	 * the transaction handle.  This also allows us to allocate
3046	 * the page (if needed) without using GFP_NOFS.
3047	 */
3048retry_grab:
3049	page = grab_cache_page_write_begin(mapping, index, flags);
3050	if (!page)
3051		return -ENOMEM;
3052	unlock_page(page);
3053
3054	/*
3055	 * With delayed allocation, we don't log the i_disksize update
3056	 * if there is delayed block allocation. But we still need
3057	 * to journalling the i_disksize update if writes to the end
3058	 * of file which has an already mapped buffer.
3059	 */
3060retry_journal:
3061	handle = ext4_journal_start(inode, EXT4_HT_WRITE_PAGE,
3062				ext4_da_write_credits(inode, pos, len));
3063	if (IS_ERR(handle)) {
3064		put_page(page);
3065		return PTR_ERR(handle);
3066	}
3067
3068	lock_page(page);
3069	if (page->mapping != mapping) {
3070		/* The page got truncated from under us */
3071		unlock_page(page);
3072		put_page(page);
3073		ext4_journal_stop(handle);
3074		goto retry_grab;
3075	}
3076	/* In case writeback began while the page was unlocked */
3077	wait_for_stable_page(page);
3078
3079#ifdef CONFIG_EXT4_FS_ENCRYPTION
3080	ret = ext4_block_write_begin(page, pos, len,
3081				     ext4_da_get_block_prep);
3082#else
3083	ret = __block_write_begin(page, pos, len, ext4_da_get_block_prep);
3084#endif
3085	if (ret < 0) {
3086		unlock_page(page);
3087		ext4_journal_stop(handle);
3088		/*
3089		 * block_write_begin may have instantiated a few blocks
3090		 * outside i_size.  Trim these off again. Don't need
3091		 * i_size_read because we hold i_mutex.
3092		 */
3093		if (pos + len > inode->i_size)
3094			ext4_truncate_failed_write(inode);
3095
3096		if (ret == -ENOSPC &&
3097		    ext4_should_retry_alloc(inode->i_sb, &retries))
3098			goto retry_journal;
3099
3100		put_page(page);
3101		return ret;
3102	}
3103
3104	*pagep = page;
3105	return ret;
3106}
3107
3108/*
3109 * Check if we should update i_disksize
3110 * when write to the end of file but not require block allocation
3111 */
3112static int ext4_da_should_update_i_disksize(struct page *page,
3113					    unsigned long offset)
3114{
3115	struct buffer_head *bh;
3116	struct inode *inode = page->mapping->host;
3117	unsigned int idx;
3118	int i;
3119
3120	bh = page_buffers(page);
3121	idx = offset >> inode->i_blkbits;
3122
3123	for (i = 0; i < idx; i++)
3124		bh = bh->b_this_page;
3125
3126	if (!buffer_mapped(bh) || (buffer_delay(bh)) || buffer_unwritten(bh))
3127		return 0;
3128	return 1;
3129}
3130
3131static int ext4_da_write_end(struct file *file,
3132			     struct address_space *mapping,
3133			     loff_t pos, unsigned len, unsigned copied,
3134			     struct page *page, void *fsdata)
3135{
3136	struct inode *inode = mapping->host;
3137	int ret = 0, ret2;
3138	handle_t *handle = ext4_journal_current_handle();
3139	loff_t new_i_size;
3140	unsigned long start, end;
3141	int write_mode = (int)(unsigned long)fsdata;
3142
3143	if (write_mode == FALL_BACK_TO_NONDELALLOC)
3144		return ext4_write_end(file, mapping, pos,
3145				      len, copied, page, fsdata);
3146
3147	trace_ext4_da_write_end(inode, pos, len, copied);
3148	start = pos & (PAGE_SIZE - 1);
3149	end = start + copied - 1;
3150
3151	/*
3152	 * generic_write_end() will run mark_inode_dirty() if i_size
3153	 * changes.  So let's piggyback the i_disksize mark_inode_dirty
3154	 * into that.
 
 
 
 
 
 
 
 
 
 
3155	 */
3156	new_i_size = pos + copied;
3157	if (copied && new_i_size > EXT4_I(inode)->i_disksize) {
3158		if (ext4_has_inline_data(inode) ||
3159		    ext4_da_should_update_i_disksize(page, end)) {
3160			ext4_update_i_disksize(inode, new_i_size);
3161			/* We need to mark inode dirty even if
3162			 * new_i_size is less that inode->i_size
3163			 * bu greater than i_disksize.(hint delalloc)
3164			 */
3165			ext4_mark_inode_dirty(handle, inode);
3166		}
3167	}
3168
3169	if (write_mode != CONVERT_INLINE_DATA &&
3170	    ext4_test_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA) &&
3171	    ext4_has_inline_data(inode))
3172		ret2 = ext4_da_write_inline_data_end(inode, pos, len, copied,
3173						     page);
3174	else
3175		ret2 = generic_write_end(file, mapping, pos, len, copied,
3176							page, fsdata);
3177
3178	copied = ret2;
3179	if (ret2 < 0)
3180		ret = ret2;
3181	ret2 = ext4_journal_stop(handle);
3182	if (!ret)
3183		ret = ret2;
3184
3185	return ret ? ret : copied;
3186}
3187
3188static void ext4_da_invalidatepage(struct page *page, unsigned int offset,
3189				   unsigned int length)
3190{
3191	/*
3192	 * Drop reserved blocks
3193	 */
3194	BUG_ON(!PageLocked(page));
3195	if (!page_has_buffers(page))
3196		goto out;
3197
3198	ext4_da_page_release_reservation(page, offset, length);
3199
3200out:
3201	ext4_invalidatepage(page, offset, length);
3202
3203	return;
3204}
3205
3206/*
3207 * Force all delayed allocation blocks to be allocated for a given inode.
3208 */
3209int ext4_alloc_da_blocks(struct inode *inode)
3210{
3211	trace_ext4_alloc_da_blocks(inode);
3212
3213	if (!EXT4_I(inode)->i_reserved_data_blocks)
3214		return 0;
3215
3216	/*
3217	 * We do something simple for now.  The filemap_flush() will
3218	 * also start triggering a write of the data blocks, which is
3219	 * not strictly speaking necessary (and for users of
3220	 * laptop_mode, not even desirable).  However, to do otherwise
3221	 * would require replicating code paths in:
3222	 *
3223	 * ext4_writepages() ->
3224	 *    write_cache_pages() ---> (via passed in callback function)
3225	 *        __mpage_da_writepage() -->
3226	 *           mpage_add_bh_to_extent()
3227	 *           mpage_da_map_blocks()
3228	 *
3229	 * The problem is that write_cache_pages(), located in
3230	 * mm/page-writeback.c, marks pages clean in preparation for
3231	 * doing I/O, which is not desirable if we're not planning on
3232	 * doing I/O at all.
3233	 *
3234	 * We could call write_cache_pages(), and then redirty all of
3235	 * the pages by calling redirty_page_for_writepage() but that
3236	 * would be ugly in the extreme.  So instead we would need to
3237	 * replicate parts of the code in the above functions,
3238	 * simplifying them because we wouldn't actually intend to
3239	 * write out the pages, but rather only collect contiguous
3240	 * logical block extents, call the multi-block allocator, and
3241	 * then update the buffer heads with the block allocations.
3242	 *
3243	 * For now, though, we'll cheat by calling filemap_flush(),
3244	 * which will map the blocks, and start the I/O, but not
3245	 * actually wait for the I/O to complete.
3246	 */
3247	return filemap_flush(inode->i_mapping);
3248}
3249
3250/*
3251 * bmap() is special.  It gets used by applications such as lilo and by
3252 * the swapper to find the on-disk block of a specific piece of data.
3253 *
3254 * Naturally, this is dangerous if the block concerned is still in the
3255 * journal.  If somebody makes a swapfile on an ext4 data-journaling
3256 * filesystem and enables swap, then they may get a nasty shock when the
3257 * data getting swapped to that swapfile suddenly gets overwritten by
3258 * the original zero's written out previously to the journal and
3259 * awaiting writeback in the kernel's buffer cache.
3260 *
3261 * So, if we see any bmap calls here on a modified, data-journaled file,
3262 * take extra steps to flush any blocks which might be in the cache.
3263 */
3264static sector_t ext4_bmap(struct address_space *mapping, sector_t block)
3265{
3266	struct inode *inode = mapping->host;
3267	journal_t *journal;
3268	int err;
3269
3270	/*
3271	 * We can get here for an inline file via the FIBMAP ioctl
3272	 */
3273	if (ext4_has_inline_data(inode))
3274		return 0;
3275
3276	if (mapping_tagged(mapping, PAGECACHE_TAG_DIRTY) &&
3277			test_opt(inode->i_sb, DELALLOC)) {
3278		/*
3279		 * With delalloc we want to sync the file
3280		 * so that we can make sure we allocate
3281		 * blocks for file
3282		 */
3283		filemap_write_and_wait(mapping);
3284	}
3285
3286	if (EXT4_JOURNAL(inode) &&
3287	    ext4_test_inode_state(inode, EXT4_STATE_JDATA)) {
3288		/*
3289		 * This is a REALLY heavyweight approach, but the use of
3290		 * bmap on dirty files is expected to be extremely rare:
3291		 * only if we run lilo or swapon on a freshly made file
3292		 * do we expect this to happen.
3293		 *
3294		 * (bmap requires CAP_SYS_RAWIO so this does not
3295		 * represent an unprivileged user DOS attack --- we'd be
3296		 * in trouble if mortal users could trigger this path at
3297		 * will.)
3298		 *
3299		 * NB. EXT4_STATE_JDATA is not set on files other than
3300		 * regular files.  If somebody wants to bmap a directory
3301		 * or symlink and gets confused because the buffer
3302		 * hasn't yet been flushed to disk, they deserve
3303		 * everything they get.
3304		 */
3305
3306		ext4_clear_inode_state(inode, EXT4_STATE_JDATA);
3307		journal = EXT4_JOURNAL(inode);
3308		jbd2_journal_lock_updates(journal);
3309		err = jbd2_journal_flush(journal);
3310		jbd2_journal_unlock_updates(journal);
3311
3312		if (err)
3313			return 0;
3314	}
3315
3316	return generic_block_bmap(mapping, block, ext4_get_block);
3317}
3318
3319static int ext4_readpage(struct file *file, struct page *page)
3320{
3321	int ret = -EAGAIN;
3322	struct inode *inode = page->mapping->host;
3323
3324	trace_ext4_readpage(page);
3325
3326	if (ext4_has_inline_data(inode))
3327		ret = ext4_readpage_inline(inode, page);
3328
3329	if (ret == -EAGAIN)
3330		return ext4_mpage_readpages(page->mapping, NULL, page, 1);
3331
3332	return ret;
3333}
3334
3335static int
3336ext4_readpages(struct file *file, struct address_space *mapping,
3337		struct list_head *pages, unsigned nr_pages)
3338{
3339	struct inode *inode = mapping->host;
3340
3341	/* If the file has inline data, no need to do readpages. */
3342	if (ext4_has_inline_data(inode))
3343		return 0;
3344
3345	return ext4_mpage_readpages(mapping, pages, NULL, nr_pages);
3346}
3347
3348static void ext4_invalidatepage(struct page *page, unsigned int offset,
3349				unsigned int length)
3350{
3351	trace_ext4_invalidatepage(page, offset, length);
3352
3353	/* No journalling happens on data buffers when this function is used */
3354	WARN_ON(page_has_buffers(page) && buffer_jbd(page_buffers(page)));
3355
3356	block_invalidatepage(page, offset, length);
3357}
3358
3359static int __ext4_journalled_invalidatepage(struct page *page,
3360					    unsigned int offset,
3361					    unsigned int length)
3362{
3363	journal_t *journal = EXT4_JOURNAL(page->mapping->host);
3364
3365	trace_ext4_journalled_invalidatepage(page, offset, length);
3366
3367	/*
3368	 * If it's a full truncate we just forget about the pending dirtying
3369	 */
3370	if (offset == 0 && length == PAGE_SIZE)
3371		ClearPageChecked(page);
3372
3373	return jbd2_journal_invalidatepage(journal, page, offset, length);
3374}
3375
3376/* Wrapper for aops... */
3377static void ext4_journalled_invalidatepage(struct page *page,
3378					   unsigned int offset,
3379					   unsigned int length)
3380{
3381	WARN_ON(__ext4_journalled_invalidatepage(page, offset, length) < 0);
3382}
3383
3384static int ext4_releasepage(struct page *page, gfp_t wait)
3385{
3386	journal_t *journal = EXT4_JOURNAL(page->mapping->host);
3387
3388	trace_ext4_releasepage(page);
3389
3390	/* Page has dirty journalled data -> cannot release */
3391	if (PageChecked(page))
3392		return 0;
3393	if (journal)
3394		return jbd2_journal_try_to_free_buffers(journal, page, wait);
3395	else
3396		return try_to_free_buffers(page);
3397}
3398
3399static bool ext4_inode_datasync_dirty(struct inode *inode)
3400{
3401	journal_t *journal = EXT4_SB(inode->i_sb)->s_journal;
3402
3403	if (journal)
3404		return !jbd2_transaction_committed(journal,
3405					EXT4_I(inode)->i_datasync_tid);
 
 
 
 
 
 
3406	/* Any metadata buffers to write? */
3407	if (!list_empty(&inode->i_mapping->private_list))
3408		return true;
3409	return inode->i_state & I_DIRTY_DATASYNC;
3410}
3411
3412static int ext4_iomap_begin(struct inode *inode, loff_t offset, loff_t length,
3413			    unsigned flags, struct iomap *iomap)
 
3414{
3415	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
3416	unsigned int blkbits = inode->i_blkbits;
3417	unsigned long first_block = offset >> blkbits;
3418	unsigned long last_block = (offset + length - 1) >> blkbits;
3419	struct ext4_map_blocks map;
3420	bool delalloc = false;
3421	int ret;
3422
3423
3424	if (flags & IOMAP_REPORT) {
3425		if (ext4_has_inline_data(inode)) {
3426			ret = ext4_inline_data_iomap(inode, iomap);
3427			if (ret != -EAGAIN) {
3428				if (ret == 0 && offset >= iomap->length)
3429					ret = -ENOENT;
3430				return ret;
3431			}
3432		}
3433	} else {
3434		if (WARN_ON_ONCE(ext4_has_inline_data(inode)))
3435			return -ERANGE;
3436	}
3437
3438	map.m_lblk = first_block;
3439	map.m_len = last_block - first_block + 1;
3440
3441	if (flags & IOMAP_REPORT) {
3442		ret = ext4_map_blocks(NULL, inode, &map, 0);
3443		if (ret < 0)
3444			return ret;
3445
3446		if (ret == 0) {
3447			ext4_lblk_t end = map.m_lblk + map.m_len - 1;
3448			struct extent_status es;
3449
3450			ext4_es_find_delayed_extent_range(inode, map.m_lblk, end, &es);
3451
3452			if (!es.es_len || es.es_lblk > end) {
3453				/* entire range is a hole */
3454			} else if (es.es_lblk > map.m_lblk) {
3455				/* range starts with a hole */
3456				map.m_len = es.es_lblk - map.m_lblk;
3457			} else {
3458				ext4_lblk_t offs = 0;
3459
3460				if (es.es_lblk < map.m_lblk)
3461					offs = map.m_lblk - es.es_lblk;
3462				map.m_lblk = es.es_lblk + offs;
3463				map.m_len = es.es_len - offs;
3464				delalloc = true;
3465			}
3466		}
3467	} else if (flags & IOMAP_WRITE) {
3468		int dio_credits;
3469		handle_t *handle;
3470		int retries = 0;
3471
3472		/* Trim mapping request to maximum we can map at once for DIO */
3473		if (map.m_len > DIO_MAX_BLOCKS)
3474			map.m_len = DIO_MAX_BLOCKS;
3475		dio_credits = ext4_chunk_trans_blocks(inode, map.m_len);
3476retry:
3477		/*
3478		 * Either we allocate blocks and then we don't get unwritten
3479		 * extent so we have reserved enough credits, or the blocks
3480		 * are already allocated and unwritten and in that case
3481		 * extent conversion fits in the credits as well.
3482		 */
3483		handle = ext4_journal_start(inode, EXT4_HT_MAP_BLOCKS,
3484					    dio_credits);
3485		if (IS_ERR(handle))
3486			return PTR_ERR(handle);
3487
3488		ret = ext4_map_blocks(handle, inode, &map,
3489				      EXT4_GET_BLOCKS_CREATE_ZERO);
3490		if (ret < 0) {
3491			ext4_journal_stop(handle);
3492			if (ret == -ENOSPC &&
3493			    ext4_should_retry_alloc(inode->i_sb, &retries))
3494				goto retry;
3495			return ret;
3496		}
3497
3498		/*
3499		 * If we added blocks beyond i_size, we need to make sure they
3500		 * will get truncated if we crash before updating i_size in
3501		 * ext4_iomap_end(). For faults we don't need to do that (and
3502		 * even cannot because for orphan list operations inode_lock is
3503		 * required) - if we happen to instantiate block beyond i_size,
3504		 * it is because we race with truncate which has already added
3505		 * the inode to the orphan list.
3506		 */
3507		if (!(flags & IOMAP_FAULT) && first_block + map.m_len >
3508		    (i_size_read(inode) + (1 << blkbits) - 1) >> blkbits) {
3509			int err;
3510
3511			err = ext4_orphan_add(handle, inode);
3512			if (err < 0) {
3513				ext4_journal_stop(handle);
3514				return err;
3515			}
3516		}
3517		ext4_journal_stop(handle);
3518	} else {
3519		ret = ext4_map_blocks(NULL, inode, &map, 0);
3520		if (ret < 0)
3521			return ret;
3522	}
3523
 
 
 
 
 
3524	iomap->flags = 0;
3525	if (ext4_inode_datasync_dirty(inode))
 
3526		iomap->flags |= IOMAP_F_DIRTY;
3527	iomap->bdev = inode->i_sb->s_bdev;
3528	iomap->dax_dev = sbi->s_daxdev;
3529	iomap->offset = (u64)first_block << blkbits;
3530	iomap->length = (u64)map.m_len << blkbits;
3531
3532	if (ret == 0) {
3533		iomap->type = delalloc ? IOMAP_DELALLOC : IOMAP_HOLE;
3534		iomap->addr = IOMAP_NULL_ADDR;
3535	} else {
3536		if (map.m_flags & EXT4_MAP_MAPPED) {
3537			iomap->type = IOMAP_MAPPED;
3538		} else if (map.m_flags & EXT4_MAP_UNWRITTEN) {
3539			iomap->type = IOMAP_UNWRITTEN;
3540		} else {
3541			WARN_ON_ONCE(1);
3542			return -EIO;
3543		}
3544		iomap->addr = (u64)map.m_pblk << blkbits;
3545	}
3546
3547	if (map.m_flags & EXT4_MAP_NEW)
3548		iomap->flags |= IOMAP_F_NEW;
3549
3550	return 0;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3551}
3552
3553static int ext4_iomap_end(struct inode *inode, loff_t offset, loff_t length,
3554			  ssize_t written, unsigned flags, struct iomap *iomap)
3555{
3556	int ret = 0;
3557	handle_t *handle;
3558	int blkbits = inode->i_blkbits;
3559	bool truncate = false;
3560
3561	if (!(flags & IOMAP_WRITE) || (flags & IOMAP_FAULT))
3562		return 0;
 
 
 
 
 
3563
3564	handle = ext4_journal_start(inode, EXT4_HT_INODE, 2);
3565	if (IS_ERR(handle)) {
3566		ret = PTR_ERR(handle);
3567		goto orphan_del;
3568	}
3569	if (ext4_update_inode_size(inode, offset + written))
3570		ext4_mark_inode_dirty(handle, inode);
3571	/*
3572	 * We may need to truncate allocated but not written blocks beyond EOF.
 
 
 
3573	 */
3574	if (iomap->offset + iomap->length > 
3575	    ALIGN(inode->i_size, 1 << blkbits)) {
3576		ext4_lblk_t written_blk, end_blk;
3577
3578		written_blk = (offset + written) >> blkbits;
3579		end_blk = (offset + length) >> blkbits;
3580		if (written_blk < end_blk && ext4_can_truncate(inode))
3581			truncate = true;
3582	}
3583	/*
3584	 * Remove inode from orphan list if we were extending a inode and
3585	 * everything went fine.
3586	 */
3587	if (!truncate && inode->i_nlink &&
3588	    !list_empty(&EXT4_I(inode)->i_orphan))
3589		ext4_orphan_del(handle, inode);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3590	ext4_journal_stop(handle);
3591	if (truncate) {
3592		ext4_truncate_failed_write(inode);
3593orphan_del:
3594		/*
3595		 * If truncate failed early the inode might still be on the
3596		 * orphan list; we need to make sure the inode is removed from
3597		 * the orphan list in that case.
3598		 */
3599		if (inode->i_nlink)
3600			ext4_orphan_del(NULL, inode);
3601	}
3602	return ret;
3603}
3604
3605const struct iomap_ops ext4_iomap_ops = {
3606	.iomap_begin		= ext4_iomap_begin,
3607	.iomap_end		= ext4_iomap_end,
3608};
3609
3610static int ext4_end_io_dio(struct kiocb *iocb, loff_t offset,
3611			    ssize_t size, void *private)
3612{
3613        ext4_io_end_t *io_end = private;
 
 
3614
3615	/* if not async direct IO just return */
3616	if (!io_end)
3617		return 0;
3618
3619	ext_debug("ext4_end_io_dio(): io_end 0x%p "
3620		  "for inode %lu, iocb 0x%p, offset %llu, size %zd\n",
3621		  io_end, io_end->inode->i_ino, iocb, offset, size);
3622
3623	/*
3624	 * Error during AIO DIO. We cannot convert unwritten extents as the
3625	 * data was not written. Just clear the unwritten flag and drop io_end.
3626	 */
3627	if (size <= 0) {
3628		ext4_clear_io_unwritten_flag(io_end);
3629		size = 0;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3630	}
3631	io_end->offset = offset;
3632	io_end->size = size;
3633	ext4_put_io_end(io_end);
 
 
3634
3635	return 0;
3636}
3637
3638/*
3639 * Handling of direct IO writes.
3640 *
3641 * For ext4 extent files, ext4 will do direct-io write even to holes,
3642 * preallocated extents, and those write extend the file, no need to
3643 * fall back to buffered IO.
3644 *
3645 * For holes, we fallocate those blocks, mark them as unwritten
3646 * If those blocks were preallocated, we mark sure they are split, but
3647 * still keep the range to write as unwritten.
3648 *
3649 * The unwritten extents will be converted to written when DIO is completed.
3650 * For async direct IO, since the IO may still pending when return, we
3651 * set up an end_io call back function, which will do the conversion
3652 * when async direct IO completed.
3653 *
3654 * If the O_DIRECT write will extend the file then add this inode to the
3655 * orphan list.  So recovery will truncate it back to the original size
3656 * if the machine crashes during the write.
3657 *
3658 */
3659static ssize_t ext4_direct_IO_write(struct kiocb *iocb, struct iov_iter *iter)
3660{
3661	struct file *file = iocb->ki_filp;
3662	struct inode *inode = file->f_mapping->host;
3663	struct ext4_inode_info *ei = EXT4_I(inode);
3664	ssize_t ret;
3665	loff_t offset = iocb->ki_pos;
3666	size_t count = iov_iter_count(iter);
3667	int overwrite = 0;
3668	get_block_t *get_block_func = NULL;
3669	int dio_flags = 0;
3670	loff_t final_size = offset + count;
3671	int orphan = 0;
3672	handle_t *handle;
3673
3674	if (final_size > inode->i_size || final_size > ei->i_disksize) {
3675		/* Credits for sb + inode write */
3676		handle = ext4_journal_start(inode, EXT4_HT_INODE, 2);
3677		if (IS_ERR(handle)) {
3678			ret = PTR_ERR(handle);
3679			goto out;
3680		}
3681		ret = ext4_orphan_add(handle, inode);
3682		if (ret) {
3683			ext4_journal_stop(handle);
3684			goto out;
3685		}
3686		orphan = 1;
3687		ext4_update_i_disksize(inode, inode->i_size);
3688		ext4_journal_stop(handle);
3689	}
3690
3691	BUG_ON(iocb->private == NULL);
3692
3693	/*
3694	 * Make all waiters for direct IO properly wait also for extent
3695	 * conversion. This also disallows race between truncate() and
3696	 * overwrite DIO as i_dio_count needs to be incremented under i_mutex.
3697	 */
3698	inode_dio_begin(inode);
 
 
 
 
3699
3700	/* If we do a overwrite dio, i_mutex locking can be released */
3701	overwrite = *((int *)iocb->private);
 
 
 
 
 
 
 
 
 
 
3702
3703	if (overwrite)
3704		inode_unlock(inode);
3705
3706	/*
3707	 * For extent mapped files we could direct write to holes and fallocate.
3708	 *
3709	 * Allocated blocks to fill the hole are marked as unwritten to prevent
3710	 * parallel buffered read to expose the stale data before DIO complete
3711	 * the data IO.
3712	 *
3713	 * As to previously fallocated extents, ext4 get_block will just simply
3714	 * mark the buffer mapped but still keep the extents unwritten.
3715	 *
3716	 * For non AIO case, we will convert those unwritten extents to written
3717	 * after return back from blockdev_direct_IO. That way we save us from
3718	 * allocating io_end structure and also the overhead of offloading
3719	 * the extent convertion to a workqueue.
3720	 *
3721	 * For async DIO, the conversion needs to be deferred when the
3722	 * IO is completed. The ext4 end_io callback function will be
3723	 * called to take care of the conversion work.  Here for async
3724	 * case, we allocate an io_end structure to hook to the iocb.
3725	 */
3726	iocb->private = NULL;
3727	if (overwrite)
3728		get_block_func = ext4_dio_get_block_overwrite;
3729	else if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS) ||
3730		   round_down(offset, i_blocksize(inode)) >= inode->i_size) {
3731		get_block_func = ext4_dio_get_block;
3732		dio_flags = DIO_LOCKING | DIO_SKIP_HOLES;
3733	} else if (is_sync_kiocb(iocb)) {
3734		get_block_func = ext4_dio_get_block_unwritten_sync;
3735		dio_flags = DIO_LOCKING;
3736	} else {
3737		get_block_func = ext4_dio_get_block_unwritten_async;
3738		dio_flags = DIO_LOCKING;
3739	}
3740	ret = __blockdev_direct_IO(iocb, inode, inode->i_sb->s_bdev, iter,
3741				   get_block_func, ext4_end_io_dio, NULL,
3742				   dio_flags);
3743
3744	if (ret > 0 && !overwrite && ext4_test_inode_state(inode,
3745						EXT4_STATE_DIO_UNWRITTEN)) {
3746		int err;
3747		/*
3748		 * for non AIO case, since the IO is already
3749		 * completed, we could do the conversion right here
3750		 */
3751		err = ext4_convert_unwritten_extents(NULL, inode,
3752						     offset, ret);
3753		if (err < 0)
3754			ret = err;
3755		ext4_clear_inode_state(inode, EXT4_STATE_DIO_UNWRITTEN);
3756	}
3757
3758	inode_dio_end(inode);
3759	/* take i_mutex locking again if we do a ovewrite dio */
3760	if (overwrite)
3761		inode_lock(inode);
3762
3763	if (ret < 0 && final_size > inode->i_size)
3764		ext4_truncate_failed_write(inode);
 
 
 
3765
3766	/* Handle extending of i_size after direct IO write */
3767	if (orphan) {
3768		int err;
3769
3770		/* Credits for sb + inode write */
3771		handle = ext4_journal_start(inode, EXT4_HT_INODE, 2);
3772		if (IS_ERR(handle)) {
3773			/*
3774			 * We wrote the data but cannot extend
3775			 * i_size. Bail out. In async io case, we do
3776			 * not return error here because we have
3777			 * already submmitted the corresponding
3778			 * bio. Returning error here makes the caller
3779			 * think that this IO is done and failed
3780			 * resulting in race with bio's completion
3781			 * handler.
3782			 */
3783			if (!ret)
3784				ret = PTR_ERR(handle);
3785			if (inode->i_nlink)
3786				ext4_orphan_del(NULL, inode);
3787
3788			goto out;
3789		}
3790		if (inode->i_nlink)
3791			ext4_orphan_del(handle, inode);
3792		if (ret > 0) {
3793			loff_t end = offset + ret;
3794			if (end > inode->i_size || end > ei->i_disksize) {
3795				ext4_update_i_disksize(inode, end);
3796				if (end > inode->i_size)
3797					i_size_write(inode, end);
3798				/*
3799				 * We're going to return a positive `ret'
3800				 * here due to non-zero-length I/O, so there's
3801				 * no way of reporting error returns from
3802				 * ext4_mark_inode_dirty() to userspace.  So
3803				 * ignore it.
3804				 */
3805				ext4_mark_inode_dirty(handle, inode);
3806			}
3807		}
3808		err = ext4_journal_stop(handle);
3809		if (ret == 0)
3810			ret = err;
3811	}
3812out:
3813	return ret;
3814}
3815
3816static ssize_t ext4_direct_IO_read(struct kiocb *iocb, struct iov_iter *iter)
3817{
3818	struct address_space *mapping = iocb->ki_filp->f_mapping;
3819	struct inode *inode = mapping->host;
3820	size_t count = iov_iter_count(iter);
3821	ssize_t ret;
3822
3823	/*
3824	 * Shared inode_lock is enough for us - it protects against concurrent
3825	 * writes & truncates and since we take care of writing back page cache,
3826	 * we are protected against page writeback as well.
3827	 */
3828	inode_lock_shared(inode);
3829	ret = filemap_write_and_wait_range(mapping, iocb->ki_pos,
3830					   iocb->ki_pos + count - 1);
3831	if (ret)
3832		goto out_unlock;
3833	ret = __blockdev_direct_IO(iocb, inode, inode->i_sb->s_bdev,
3834				   iter, ext4_dio_get_block, NULL, NULL, 0);
3835out_unlock:
3836	inode_unlock_shared(inode);
3837	return ret;
3838}
3839
3840static ssize_t ext4_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
 
 
3841{
3842	struct file *file = iocb->ki_filp;
3843	struct inode *inode = file->f_mapping->host;
3844	size_t count = iov_iter_count(iter);
3845	loff_t offset = iocb->ki_pos;
3846	ssize_t ret;
3847
3848#ifdef CONFIG_EXT4_FS_ENCRYPTION
3849	if (ext4_encrypted_inode(inode) && S_ISREG(inode->i_mode))
3850		return 0;
3851#endif
 
 
 
 
 
 
 
3852
3853	/*
3854	 * If we are doing data journalling we don't support O_DIRECT
3855	 */
3856	if (ext4_should_journal_data(inode))
3857		return 0;
 
3858
3859	/* Let buffer I/O handle the inline data case. */
3860	if (ext4_has_inline_data(inode))
3861		return 0;
 
 
 
 
 
3862
3863	trace_ext4_direct_IO_enter(inode, offset, count, iov_iter_rw(iter));
3864	if (iov_iter_rw(iter) == READ)
3865		ret = ext4_direct_IO_read(iocb, iter);
3866	else
3867		ret = ext4_direct_IO_write(iocb, iter);
3868	trace_ext4_direct_IO_exit(inode, offset, count, iov_iter_rw(iter), ret);
3869	return ret;
 
 
 
 
 
 
 
 
 
 
 
3870}
3871
 
 
 
 
3872/*
3873 * Pages can be marked dirty completely asynchronously from ext4's journalling
3874 * activity.  By filemap_sync_pte(), try_to_unmap_one(), etc.  We cannot do
3875 * much here because ->set_page_dirty is called under VFS locks.  The page is
3876 * not necessarily locked.
3877 *
3878 * We cannot just dirty the page and leave attached buffers clean, because the
3879 * buffers' dirty state is "definitive".  We cannot just set the buffers dirty
3880 * or jbddirty because all the journalling code will explode.
3881 *
3882 * So what we do is to mark the page "pending dirty" and next time writepage
3883 * is called, propagate that into the buffers appropriately.
3884 */
3885static int ext4_journalled_set_page_dirty(struct page *page)
3886{
3887	SetPageChecked(page);
3888	return __set_page_dirty_nobuffers(page);
3889}
3890
3891static int ext4_set_page_dirty(struct page *page)
3892{
3893	WARN_ON_ONCE(!PageLocked(page) && !PageDirty(page));
3894	WARN_ON_ONCE(!page_has_buffers(page));
3895	return __set_page_dirty_buffers(page);
3896}
3897
 
 
 
 
 
 
 
3898static const struct address_space_operations ext4_aops = {
3899	.readpage		= ext4_readpage,
3900	.readpages		= ext4_readpages,
3901	.writepage		= ext4_writepage,
3902	.writepages		= ext4_writepages,
3903	.write_begin		= ext4_write_begin,
3904	.write_end		= ext4_write_end,
3905	.set_page_dirty		= ext4_set_page_dirty,
3906	.bmap			= ext4_bmap,
3907	.invalidatepage		= ext4_invalidatepage,
3908	.releasepage		= ext4_releasepage,
3909	.direct_IO		= ext4_direct_IO,
3910	.migratepage		= buffer_migrate_page,
3911	.is_partially_uptodate  = block_is_partially_uptodate,
3912	.error_remove_page	= generic_error_remove_page,
 
3913};
3914
3915static const struct address_space_operations ext4_journalled_aops = {
3916	.readpage		= ext4_readpage,
3917	.readpages		= ext4_readpages,
3918	.writepage		= ext4_writepage,
3919	.writepages		= ext4_writepages,
3920	.write_begin		= ext4_write_begin,
3921	.write_end		= ext4_journalled_write_end,
3922	.set_page_dirty		= ext4_journalled_set_page_dirty,
3923	.bmap			= ext4_bmap,
3924	.invalidatepage		= ext4_journalled_invalidatepage,
3925	.releasepage		= ext4_releasepage,
3926	.direct_IO		= ext4_direct_IO,
3927	.is_partially_uptodate  = block_is_partially_uptodate,
3928	.error_remove_page	= generic_error_remove_page,
 
3929};
3930
3931static const struct address_space_operations ext4_da_aops = {
3932	.readpage		= ext4_readpage,
3933	.readpages		= ext4_readpages,
3934	.writepage		= ext4_writepage,
3935	.writepages		= ext4_writepages,
3936	.write_begin		= ext4_da_write_begin,
3937	.write_end		= ext4_da_write_end,
3938	.set_page_dirty		= ext4_set_page_dirty,
3939	.bmap			= ext4_bmap,
3940	.invalidatepage		= ext4_da_invalidatepage,
3941	.releasepage		= ext4_releasepage,
3942	.direct_IO		= ext4_direct_IO,
3943	.migratepage		= buffer_migrate_page,
3944	.is_partially_uptodate  = block_is_partially_uptodate,
3945	.error_remove_page	= generic_error_remove_page,
 
3946};
3947
3948static const struct address_space_operations ext4_dax_aops = {
3949	.writepages		= ext4_dax_writepages,
3950	.direct_IO		= noop_direct_IO,
3951	.set_page_dirty		= noop_set_page_dirty,
 
3952	.invalidatepage		= noop_invalidatepage,
 
3953};
3954
3955void ext4_set_aops(struct inode *inode)
3956{
3957	switch (ext4_inode_journal_mode(inode)) {
3958	case EXT4_INODE_ORDERED_DATA_MODE:
3959	case EXT4_INODE_WRITEBACK_DATA_MODE:
3960		break;
3961	case EXT4_INODE_JOURNAL_DATA_MODE:
3962		inode->i_mapping->a_ops = &ext4_journalled_aops;
3963		return;
3964	default:
3965		BUG();
3966	}
3967	if (IS_DAX(inode))
3968		inode->i_mapping->a_ops = &ext4_dax_aops;
3969	else if (test_opt(inode->i_sb, DELALLOC))
3970		inode->i_mapping->a_ops = &ext4_da_aops;
3971	else
3972		inode->i_mapping->a_ops = &ext4_aops;
3973}
3974
3975static int __ext4_block_zero_page_range(handle_t *handle,
3976		struct address_space *mapping, loff_t from, loff_t length)
3977{
3978	ext4_fsblk_t index = from >> PAGE_SHIFT;
3979	unsigned offset = from & (PAGE_SIZE-1);
3980	unsigned blocksize, pos;
3981	ext4_lblk_t iblock;
3982	struct inode *inode = mapping->host;
3983	struct buffer_head *bh;
3984	struct page *page;
3985	int err = 0;
3986
3987	page = find_or_create_page(mapping, from >> PAGE_SHIFT,
3988				   mapping_gfp_constraint(mapping, ~__GFP_FS));
3989	if (!page)
3990		return -ENOMEM;
3991
3992	blocksize = inode->i_sb->s_blocksize;
3993
3994	iblock = index << (PAGE_SHIFT - inode->i_sb->s_blocksize_bits);
3995
3996	if (!page_has_buffers(page))
3997		create_empty_buffers(page, blocksize, 0);
3998
3999	/* Find the buffer that contains "offset" */
4000	bh = page_buffers(page);
4001	pos = blocksize;
4002	while (offset >= pos) {
4003		bh = bh->b_this_page;
4004		iblock++;
4005		pos += blocksize;
4006	}
4007	if (buffer_freed(bh)) {
4008		BUFFER_TRACE(bh, "freed: skip");
4009		goto unlock;
4010	}
4011	if (!buffer_mapped(bh)) {
4012		BUFFER_TRACE(bh, "unmapped");
4013		ext4_get_block(inode, iblock, bh, 0);
4014		/* unmapped? It's a hole - nothing to do */
4015		if (!buffer_mapped(bh)) {
4016			BUFFER_TRACE(bh, "still unmapped");
4017			goto unlock;
4018		}
4019	}
4020
4021	/* Ok, it's mapped. Make sure it's up-to-date */
4022	if (PageUptodate(page))
4023		set_buffer_uptodate(bh);
4024
4025	if (!buffer_uptodate(bh)) {
4026		err = -EIO;
4027		ll_rw_block(REQ_OP_READ, 0, 1, &bh);
4028		wait_on_buffer(bh);
4029		/* Uhhuh. Read error. Complain and punt. */
4030		if (!buffer_uptodate(bh))
4031			goto unlock;
4032		if (S_ISREG(inode->i_mode) &&
4033		    ext4_encrypted_inode(inode)) {
4034			/* We expect the key to be set. */
4035			BUG_ON(!fscrypt_has_encryption_key(inode));
4036			BUG_ON(blocksize != PAGE_SIZE);
4037			WARN_ON_ONCE(fscrypt_decrypt_page(page->mapping->host,
4038						page, PAGE_SIZE, 0, page->index));
 
 
 
4039		}
4040	}
4041	if (ext4_should_journal_data(inode)) {
4042		BUFFER_TRACE(bh, "get write access");
4043		err = ext4_journal_get_write_access(handle, bh);
4044		if (err)
4045			goto unlock;
4046	}
4047	zero_user(page, offset, length);
4048	BUFFER_TRACE(bh, "zeroed end of block");
4049
4050	if (ext4_should_journal_data(inode)) {
4051		err = ext4_handle_dirty_metadata(handle, inode, bh);
4052	} else {
4053		err = 0;
4054		mark_buffer_dirty(bh);
4055		if (ext4_should_order_data(inode))
4056			err = ext4_jbd2_inode_add_write(handle, inode);
 
4057	}
4058
4059unlock:
4060	unlock_page(page);
4061	put_page(page);
4062	return err;
4063}
4064
4065/*
4066 * ext4_block_zero_page_range() zeros out a mapping of length 'length'
4067 * starting from file offset 'from'.  The range to be zero'd must
4068 * be contained with in one block.  If the specified range exceeds
4069 * the end of the block it will be shortened to end of the block
4070 * that cooresponds to 'from'
4071 */
4072static int ext4_block_zero_page_range(handle_t *handle,
4073		struct address_space *mapping, loff_t from, loff_t length)
4074{
4075	struct inode *inode = mapping->host;
4076	unsigned offset = from & (PAGE_SIZE-1);
4077	unsigned blocksize = inode->i_sb->s_blocksize;
4078	unsigned max = blocksize - (offset & (blocksize - 1));
4079
4080	/*
4081	 * correct length if it does not fall between
4082	 * 'from' and the end of the block
4083	 */
4084	if (length > max || length < 0)
4085		length = max;
4086
4087	if (IS_DAX(inode)) {
4088		return iomap_zero_range(inode, from, length, NULL,
4089					&ext4_iomap_ops);
4090	}
4091	return __ext4_block_zero_page_range(handle, mapping, from, length);
4092}
4093
4094/*
4095 * ext4_block_truncate_page() zeroes out a mapping from file offset `from'
4096 * up to the end of the block which corresponds to `from'.
4097 * This required during truncate. We need to physically zero the tail end
4098 * of that block so it doesn't yield old data if the file is later grown.
4099 */
4100static int ext4_block_truncate_page(handle_t *handle,
4101		struct address_space *mapping, loff_t from)
4102{
4103	unsigned offset = from & (PAGE_SIZE-1);
4104	unsigned length;
4105	unsigned blocksize;
4106	struct inode *inode = mapping->host;
4107
4108	/* If we are processing an encrypted inode during orphan list handling */
4109	if (ext4_encrypted_inode(inode) && !fscrypt_has_encryption_key(inode))
4110		return 0;
4111
4112	blocksize = inode->i_sb->s_blocksize;
4113	length = blocksize - (offset & (blocksize - 1));
4114
4115	return ext4_block_zero_page_range(handle, mapping, from, length);
4116}
4117
4118int ext4_zero_partial_blocks(handle_t *handle, struct inode *inode,
4119			     loff_t lstart, loff_t length)
4120{
4121	struct super_block *sb = inode->i_sb;
4122	struct address_space *mapping = inode->i_mapping;
4123	unsigned partial_start, partial_end;
4124	ext4_fsblk_t start, end;
4125	loff_t byte_end = (lstart + length - 1);
4126	int err = 0;
4127
4128	partial_start = lstart & (sb->s_blocksize - 1);
4129	partial_end = byte_end & (sb->s_blocksize - 1);
4130
4131	start = lstart >> sb->s_blocksize_bits;
4132	end = byte_end >> sb->s_blocksize_bits;
4133
4134	/* Handle partial zero within the single block */
4135	if (start == end &&
4136	    (partial_start || (partial_end != sb->s_blocksize - 1))) {
4137		err = ext4_block_zero_page_range(handle, mapping,
4138						 lstart, length);
4139		return err;
4140	}
4141	/* Handle partial zero out on the start of the range */
4142	if (partial_start) {
4143		err = ext4_block_zero_page_range(handle, mapping,
4144						 lstart, sb->s_blocksize);
4145		if (err)
4146			return err;
4147	}
4148	/* Handle partial zero out on the end of the range */
4149	if (partial_end != sb->s_blocksize - 1)
4150		err = ext4_block_zero_page_range(handle, mapping,
4151						 byte_end - partial_end,
4152						 partial_end + 1);
4153	return err;
4154}
4155
4156int ext4_can_truncate(struct inode *inode)
4157{
4158	if (S_ISREG(inode->i_mode))
4159		return 1;
4160	if (S_ISDIR(inode->i_mode))
4161		return 1;
4162	if (S_ISLNK(inode->i_mode))
4163		return !ext4_inode_is_fast_symlink(inode);
4164	return 0;
4165}
4166
4167/*
4168 * We have to make sure i_disksize gets properly updated before we truncate
4169 * page cache due to hole punching or zero range. Otherwise i_disksize update
4170 * can get lost as it may have been postponed to submission of writeback but
4171 * that will never happen after we truncate page cache.
4172 */
4173int ext4_update_disksize_before_punch(struct inode *inode, loff_t offset,
4174				      loff_t len)
4175{
4176	handle_t *handle;
 
 
4177	loff_t size = i_size_read(inode);
4178
4179	WARN_ON(!inode_is_locked(inode));
4180	if (offset > size || offset + len < size)
4181		return 0;
4182
4183	if (EXT4_I(inode)->i_disksize >= size)
4184		return 0;
4185
4186	handle = ext4_journal_start(inode, EXT4_HT_MISC, 1);
4187	if (IS_ERR(handle))
4188		return PTR_ERR(handle);
4189	ext4_update_i_disksize(inode, size);
4190	ext4_mark_inode_dirty(handle, inode);
4191	ext4_journal_stop(handle);
4192
4193	return 0;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
4194}
4195
4196/*
4197 * ext4_punch_hole: punches a hole in a file by releasing the blocks
4198 * associated with the given offset and length
4199 *
4200 * @inode:  File inode
4201 * @offset: The offset where the hole will begin
4202 * @len:    The length of the hole
4203 *
4204 * Returns: 0 on success or negative on failure
4205 */
4206
4207int ext4_punch_hole(struct inode *inode, loff_t offset, loff_t length)
4208{
4209	struct super_block *sb = inode->i_sb;
4210	ext4_lblk_t first_block, stop_block;
4211	struct address_space *mapping = inode->i_mapping;
4212	loff_t first_block_offset, last_block_offset;
4213	handle_t *handle;
4214	unsigned int credits;
4215	int ret = 0;
4216
4217	if (!S_ISREG(inode->i_mode))
4218		return -EOPNOTSUPP;
4219
4220	trace_ext4_punch_hole(inode, offset, length, 0);
4221
 
 
 
 
 
 
 
 
 
4222	/*
4223	 * Write out all dirty pages to avoid race conditions
4224	 * Then release them.
4225	 */
4226	if (mapping_tagged(mapping, PAGECACHE_TAG_DIRTY)) {
4227		ret = filemap_write_and_wait_range(mapping, offset,
4228						   offset + length - 1);
4229		if (ret)
4230			return ret;
4231	}
4232
4233	inode_lock(inode);
4234
4235	/* No need to punch hole beyond i_size */
4236	if (offset >= inode->i_size)
4237		goto out_mutex;
4238
4239	/*
4240	 * If the hole extends beyond i_size, set the hole
4241	 * to end after the page that contains i_size
4242	 */
4243	if (offset + length > inode->i_size) {
4244		length = inode->i_size +
4245		   PAGE_SIZE - (inode->i_size & (PAGE_SIZE - 1)) -
4246		   offset;
4247	}
4248
4249	if (offset & (sb->s_blocksize - 1) ||
4250	    (offset + length) & (sb->s_blocksize - 1)) {
4251		/*
4252		 * Attach jinode to inode for jbd2 if we do any zeroing of
4253		 * partial block
4254		 */
4255		ret = ext4_inode_attach_jinode(inode);
4256		if (ret < 0)
4257			goto out_mutex;
4258
4259	}
4260
4261	/* Wait all existing dio workers, newcomers will block on i_mutex */
4262	inode_dio_wait(inode);
4263
4264	/*
4265	 * Prevent page faults from reinstantiating pages we have released from
4266	 * page cache.
4267	 */
4268	down_write(&EXT4_I(inode)->i_mmap_sem);
 
 
 
 
 
4269	first_block_offset = round_up(offset, sb->s_blocksize);
4270	last_block_offset = round_down((offset + length), sb->s_blocksize) - 1;
4271
4272	/* Now release the pages and zero block aligned part of pages*/
4273	if (last_block_offset > first_block_offset) {
4274		ret = ext4_update_disksize_before_punch(inode, offset, length);
4275		if (ret)
4276			goto out_dio;
4277		truncate_pagecache_range(inode, first_block_offset,
4278					 last_block_offset);
4279	}
4280
4281	if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
4282		credits = ext4_writepage_trans_blocks(inode);
4283	else
4284		credits = ext4_blocks_for_truncate(inode);
4285	handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE, credits);
4286	if (IS_ERR(handle)) {
4287		ret = PTR_ERR(handle);
4288		ext4_std_error(sb, ret);
4289		goto out_dio;
4290	}
4291
4292	ret = ext4_zero_partial_blocks(handle, inode, offset,
4293				       length);
4294	if (ret)
4295		goto out_stop;
4296
4297	first_block = (offset + sb->s_blocksize - 1) >>
4298		EXT4_BLOCK_SIZE_BITS(sb);
4299	stop_block = (offset + length) >> EXT4_BLOCK_SIZE_BITS(sb);
4300
4301	/* If there are no blocks to remove, return now */
4302	if (first_block >= stop_block)
4303		goto out_stop;
4304
4305	down_write(&EXT4_I(inode)->i_data_sem);
4306	ext4_discard_preallocations(inode);
4307
4308	ret = ext4_es_remove_extent(inode, first_block,
4309				    stop_block - first_block);
4310	if (ret) {
4311		up_write(&EXT4_I(inode)->i_data_sem);
4312		goto out_stop;
4313	}
4314
4315	if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
4316		ret = ext4_ext_remove_space(inode, first_block,
4317					    stop_block - 1);
4318	else
4319		ret = ext4_ind_remove_space(handle, inode, first_block,
4320					    stop_block);
4321
4322	up_write(&EXT4_I(inode)->i_data_sem);
 
 
4323	if (IS_SYNC(inode))
4324		ext4_handle_sync(handle);
4325
4326	inode->i_mtime = inode->i_ctime = current_time(inode);
4327	ext4_mark_inode_dirty(handle, inode);
 
 
4328	if (ret >= 0)
4329		ext4_update_inode_fsync_trans(handle, inode, 1);
4330out_stop:
4331	ext4_journal_stop(handle);
4332out_dio:
4333	up_write(&EXT4_I(inode)->i_mmap_sem);
4334out_mutex:
4335	inode_unlock(inode);
4336	return ret;
4337}
4338
4339int ext4_inode_attach_jinode(struct inode *inode)
4340{
4341	struct ext4_inode_info *ei = EXT4_I(inode);
4342	struct jbd2_inode *jinode;
4343
4344	if (ei->jinode || !EXT4_SB(inode->i_sb)->s_journal)
4345		return 0;
4346
4347	jinode = jbd2_alloc_inode(GFP_KERNEL);
4348	spin_lock(&inode->i_lock);
4349	if (!ei->jinode) {
4350		if (!jinode) {
4351			spin_unlock(&inode->i_lock);
4352			return -ENOMEM;
4353		}
4354		ei->jinode = jinode;
4355		jbd2_journal_init_jbd_inode(ei->jinode, inode);
4356		jinode = NULL;
4357	}
4358	spin_unlock(&inode->i_lock);
4359	if (unlikely(jinode != NULL))
4360		jbd2_free_inode(jinode);
4361	return 0;
4362}
4363
4364/*
4365 * ext4_truncate()
4366 *
4367 * We block out ext4_get_block() block instantiations across the entire
4368 * transaction, and VFS/VM ensures that ext4_truncate() cannot run
4369 * simultaneously on behalf of the same inode.
4370 *
4371 * As we work through the truncate and commit bits of it to the journal there
4372 * is one core, guiding principle: the file's tree must always be consistent on
4373 * disk.  We must be able to restart the truncate after a crash.
4374 *
4375 * The file's tree may be transiently inconsistent in memory (although it
4376 * probably isn't), but whenever we close off and commit a journal transaction,
4377 * the contents of (the filesystem + the journal) must be consistent and
4378 * restartable.  It's pretty simple, really: bottom up, right to left (although
4379 * left-to-right works OK too).
4380 *
4381 * Note that at recovery time, journal replay occurs *before* the restart of
4382 * truncate against the orphan inode list.
4383 *
4384 * The committed inode has the new, desired i_size (which is the same as
4385 * i_disksize in this case).  After a crash, ext4_orphan_cleanup() will see
4386 * that this inode's truncate did not complete and it will again call
4387 * ext4_truncate() to have another go.  So there will be instantiated blocks
4388 * to the right of the truncation point in a crashed ext4 filesystem.  But
4389 * that's fine - as long as they are linked from the inode, the post-crash
4390 * ext4_truncate() run will find them and release them.
4391 */
4392int ext4_truncate(struct inode *inode)
4393{
4394	struct ext4_inode_info *ei = EXT4_I(inode);
4395	unsigned int credits;
4396	int err = 0;
4397	handle_t *handle;
4398	struct address_space *mapping = inode->i_mapping;
4399
4400	/*
4401	 * There is a possibility that we're either freeing the inode
4402	 * or it's a completely new inode. In those cases we might not
4403	 * have i_mutex locked because it's not necessary.
4404	 */
4405	if (!(inode->i_state & (I_NEW|I_FREEING)))
4406		WARN_ON(!inode_is_locked(inode));
4407	trace_ext4_truncate_enter(inode);
4408
4409	if (!ext4_can_truncate(inode))
4410		return 0;
4411
4412	ext4_clear_inode_flag(inode, EXT4_INODE_EOFBLOCKS);
4413
4414	if (inode->i_size == 0 && !test_opt(inode->i_sb, NO_AUTO_DA_ALLOC))
4415		ext4_set_inode_state(inode, EXT4_STATE_DA_ALLOC_CLOSE);
4416
4417	if (ext4_has_inline_data(inode)) {
4418		int has_inline = 1;
4419
4420		err = ext4_inline_data_truncate(inode, &has_inline);
4421		if (err)
4422			return err;
4423		if (has_inline)
4424			return 0;
4425	}
4426
4427	/* If we zero-out tail of the page, we have to create jinode for jbd2 */
4428	if (inode->i_size & (inode->i_sb->s_blocksize - 1)) {
4429		if (ext4_inode_attach_jinode(inode) < 0)
4430			return 0;
4431	}
4432
4433	if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
4434		credits = ext4_writepage_trans_blocks(inode);
4435	else
4436		credits = ext4_blocks_for_truncate(inode);
4437
4438	handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE, credits);
4439	if (IS_ERR(handle))
4440		return PTR_ERR(handle);
 
 
4441
4442	if (inode->i_size & (inode->i_sb->s_blocksize - 1))
4443		ext4_block_truncate_page(handle, mapping, inode->i_size);
4444
4445	/*
4446	 * We add the inode to the orphan list, so that if this
4447	 * truncate spans multiple transactions, and we crash, we will
4448	 * resume the truncate when the filesystem recovers.  It also
4449	 * marks the inode dirty, to catch the new size.
4450	 *
4451	 * Implication: the file must always be in a sane, consistent
4452	 * truncatable state while each transaction commits.
4453	 */
4454	err = ext4_orphan_add(handle, inode);
4455	if (err)
4456		goto out_stop;
4457
4458	down_write(&EXT4_I(inode)->i_data_sem);
4459
4460	ext4_discard_preallocations(inode);
4461
4462	if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
4463		err = ext4_ext_truncate(handle, inode);
4464	else
4465		ext4_ind_truncate(handle, inode);
4466
4467	up_write(&ei->i_data_sem);
4468	if (err)
4469		goto out_stop;
4470
4471	if (IS_SYNC(inode))
4472		ext4_handle_sync(handle);
4473
4474out_stop:
4475	/*
4476	 * If this was a simple ftruncate() and the file will remain alive,
4477	 * then we need to clear up the orphan record which we created above.
4478	 * However, if this was a real unlink then we were called by
4479	 * ext4_evict_inode(), and we allow that function to clean up the
4480	 * orphan info for us.
4481	 */
4482	if (inode->i_nlink)
4483		ext4_orphan_del(handle, inode);
4484
4485	inode->i_mtime = inode->i_ctime = current_time(inode);
4486	ext4_mark_inode_dirty(handle, inode);
 
 
4487	ext4_journal_stop(handle);
4488
 
4489	trace_ext4_truncate_exit(inode);
4490	return err;
4491}
4492
4493/*
4494 * ext4_get_inode_loc returns with an extra refcount against the inode's
4495 * underlying buffer_head on success. If 'in_mem' is true, we have all
4496 * data in memory that is needed to recreate the on-disk version of this
4497 * inode.
4498 */
4499static int __ext4_get_inode_loc(struct inode *inode,
4500				struct ext4_iloc *iloc, int in_mem)
 
4501{
4502	struct ext4_group_desc	*gdp;
4503	struct buffer_head	*bh;
4504	struct super_block	*sb = inode->i_sb;
4505	ext4_fsblk_t		block;
 
4506	int			inodes_per_block, inode_offset;
4507
4508	iloc->bh = NULL;
4509	if (!ext4_valid_inum(sb, inode->i_ino))
 
4510		return -EFSCORRUPTED;
4511
4512	iloc->block_group = (inode->i_ino - 1) / EXT4_INODES_PER_GROUP(sb);
4513	gdp = ext4_get_group_desc(sb, iloc->block_group, NULL);
4514	if (!gdp)
4515		return -EIO;
4516
4517	/*
4518	 * Figure out the offset within the block group inode table
4519	 */
4520	inodes_per_block = EXT4_SB(sb)->s_inodes_per_block;
4521	inode_offset = ((inode->i_ino - 1) %
4522			EXT4_INODES_PER_GROUP(sb));
4523	block = ext4_inode_table(sb, gdp) + (inode_offset / inodes_per_block);
4524	iloc->offset = (inode_offset % inodes_per_block) * EXT4_INODE_SIZE(sb);
4525
4526	bh = sb_getblk(sb, block);
4527	if (unlikely(!bh))
4528		return -ENOMEM;
 
 
4529	if (!buffer_uptodate(bh)) {
4530		lock_buffer(bh);
4531
4532		/*
4533		 * If the buffer has the write error flag, we have failed
4534		 * to write out another inode in the same block.  In this
4535		 * case, we don't have to read the block because we may
4536		 * read the old inode data successfully.
4537		 */
4538		if (buffer_write_io_error(bh) && !buffer_uptodate(bh))
4539			set_buffer_uptodate(bh);
4540
4541		if (buffer_uptodate(bh)) {
4542			/* someone brought it uptodate while we waited */
4543			unlock_buffer(bh);
4544			goto has_buffer;
4545		}
4546
4547		/*
4548		 * If we have all information of the inode in memory and this
4549		 * is the only valid inode in the block, we need not read the
4550		 * block.
4551		 */
4552		if (in_mem) {
4553			struct buffer_head *bitmap_bh;
4554			int i, start;
4555
4556			start = inode_offset & ~(inodes_per_block - 1);
4557
4558			/* Is the inode bitmap in cache? */
4559			bitmap_bh = sb_getblk(sb, ext4_inode_bitmap(sb, gdp));
4560			if (unlikely(!bitmap_bh))
4561				goto make_io;
4562
4563			/*
4564			 * If the inode bitmap isn't in cache then the
4565			 * optimisation may end up performing two reads instead
4566			 * of one, so skip it.
4567			 */
4568			if (!buffer_uptodate(bitmap_bh)) {
4569				brelse(bitmap_bh);
4570				goto make_io;
4571			}
4572			for (i = start; i < start + inodes_per_block; i++) {
4573				if (i == inode_offset)
4574					continue;
4575				if (ext4_test_bit(i, bitmap_bh->b_data))
4576					break;
4577			}
4578			brelse(bitmap_bh);
4579			if (i == start + inodes_per_block) {
4580				/* all other inodes are free, so skip I/O */
4581				memset(bh->b_data, 0, bh->b_size);
4582				set_buffer_uptodate(bh);
4583				unlock_buffer(bh);
4584				goto has_buffer;
4585			}
4586		}
4587
4588make_io:
4589		/*
4590		 * If we need to do any I/O, try to pre-readahead extra
4591		 * blocks from the inode table.
4592		 */
 
4593		if (EXT4_SB(sb)->s_inode_readahead_blks) {
4594			ext4_fsblk_t b, end, table;
4595			unsigned num;
4596			__u32 ra_blks = EXT4_SB(sb)->s_inode_readahead_blks;
4597
4598			table = ext4_inode_table(sb, gdp);
4599			/* s_inode_readahead_blks is always a power of 2 */
4600			b = block & ~((ext4_fsblk_t) ra_blks - 1);
4601			if (table > b)
4602				b = table;
4603			end = b + ra_blks;
4604			num = EXT4_INODES_PER_GROUP(sb);
4605			if (ext4_has_group_desc_csum(sb))
4606				num -= ext4_itable_unused_count(sb, gdp);
4607			table += num / inodes_per_block;
4608			if (end > table)
4609				end = table;
4610			while (b <= end)
4611				sb_breadahead(sb, b++);
4612		}
4613
4614		/*
4615		 * There are other valid inodes in the buffer, this inode
4616		 * has in-inode xattrs, or we don't have this inode in memory.
4617		 * Read the block from disk.
4618		 */
4619		trace_ext4_load_inode(inode);
4620		get_bh(bh);
4621		bh->b_end_io = end_buffer_read_sync;
4622		submit_bh(REQ_OP_READ, REQ_META | REQ_PRIO, bh);
4623		wait_on_buffer(bh);
4624		if (!buffer_uptodate(bh)) {
4625			EXT4_ERROR_INODE_BLOCK(inode, block,
4626					       "unable to read itable block");
 
4627			brelse(bh);
4628			return -EIO;
4629		}
4630	}
4631has_buffer:
4632	iloc->bh = bh;
4633	return 0;
4634}
4635
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
4636int ext4_get_inode_loc(struct inode *inode, struct ext4_iloc *iloc)
4637{
 
 
 
4638	/* We have all inode data except xattrs in memory here. */
4639	return __ext4_get_inode_loc(inode, iloc,
4640		!ext4_test_inode_state(inode, EXT4_STATE_XATTR));
 
 
 
 
 
 
 
 
 
 
 
 
 
4641}
4642
4643static bool ext4_should_use_dax(struct inode *inode)
4644{
4645	if (!test_opt(inode->i_sb, DAX))
 
 
4646		return false;
4647	if (!S_ISREG(inode->i_mode))
4648		return false;
4649	if (ext4_should_journal_data(inode))
4650		return false;
4651	if (ext4_has_inline_data(inode))
4652		return false;
4653	if (ext4_encrypted_inode(inode))
4654		return false;
4655	return true;
 
 
 
 
 
 
 
4656}
4657
4658void ext4_set_inode_flags(struct inode *inode)
4659{
4660	unsigned int flags = EXT4_I(inode)->i_flags;
4661	unsigned int new_fl = 0;
4662
 
 
4663	if (flags & EXT4_SYNC_FL)
4664		new_fl |= S_SYNC;
4665	if (flags & EXT4_APPEND_FL)
4666		new_fl |= S_APPEND;
4667	if (flags & EXT4_IMMUTABLE_FL)
4668		new_fl |= S_IMMUTABLE;
4669	if (flags & EXT4_NOATIME_FL)
4670		new_fl |= S_NOATIME;
4671	if (flags & EXT4_DIRSYNC_FL)
4672		new_fl |= S_DIRSYNC;
4673	if (ext4_should_use_dax(inode))
 
 
 
 
4674		new_fl |= S_DAX;
 
4675	if (flags & EXT4_ENCRYPT_FL)
4676		new_fl |= S_ENCRYPTED;
 
 
 
 
4677	inode_set_flags(inode, new_fl,
4678			S_SYNC|S_APPEND|S_IMMUTABLE|S_NOATIME|S_DIRSYNC|S_DAX|
4679			S_ENCRYPTED);
4680}
4681
4682static blkcnt_t ext4_inode_blocks(struct ext4_inode *raw_inode,
4683				  struct ext4_inode_info *ei)
4684{
4685	blkcnt_t i_blocks ;
4686	struct inode *inode = &(ei->vfs_inode);
4687	struct super_block *sb = inode->i_sb;
4688
4689	if (ext4_has_feature_huge_file(sb)) {
4690		/* we are using combined 48 bit field */
4691		i_blocks = ((u64)le16_to_cpu(raw_inode->i_blocks_high)) << 32 |
4692					le32_to_cpu(raw_inode->i_blocks_lo);
4693		if (ext4_test_inode_flag(inode, EXT4_INODE_HUGE_FILE)) {
4694			/* i_blocks represent file system block size */
4695			return i_blocks  << (inode->i_blkbits - 9);
4696		} else {
4697			return i_blocks;
4698		}
4699	} else {
4700		return le32_to_cpu(raw_inode->i_blocks_lo);
4701	}
4702}
4703
4704static inline void ext4_iget_extra_inode(struct inode *inode,
4705					 struct ext4_inode *raw_inode,
4706					 struct ext4_inode_info *ei)
4707{
4708	__le32 *magic = (void *)raw_inode +
4709			EXT4_GOOD_OLD_INODE_SIZE + ei->i_extra_isize;
 
4710	if (EXT4_GOOD_OLD_INODE_SIZE + ei->i_extra_isize + sizeof(__le32) <=
4711	    EXT4_INODE_SIZE(inode->i_sb) &&
4712	    *magic == cpu_to_le32(EXT4_XATTR_MAGIC)) {
4713		ext4_set_inode_state(inode, EXT4_STATE_XATTR);
4714		ext4_find_inline_data_nolock(inode);
4715	} else
4716		EXT4_I(inode)->i_inline_off = 0;
 
4717}
4718
4719int ext4_get_projid(struct inode *inode, kprojid_t *projid)
4720{
4721	if (!ext4_has_feature_project(inode->i_sb))
4722		return -EOPNOTSUPP;
4723	*projid = EXT4_I(inode)->i_projid;
4724	return 0;
4725}
4726
4727struct inode *ext4_iget(struct super_block *sb, unsigned long ino)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
4728{
4729	struct ext4_iloc iloc;
4730	struct ext4_inode *raw_inode;
4731	struct ext4_inode_info *ei;
4732	struct inode *inode;
4733	journal_t *journal = EXT4_SB(sb)->s_journal;
4734	long ret;
4735	loff_t size;
4736	int block;
4737	uid_t i_uid;
4738	gid_t i_gid;
4739	projid_t i_projid;
4740
 
 
 
 
 
 
 
 
 
 
 
 
4741	inode = iget_locked(sb, ino);
4742	if (!inode)
4743		return ERR_PTR(-ENOMEM);
4744	if (!(inode->i_state & I_NEW))
4745		return inode;
4746
4747	ei = EXT4_I(inode);
4748	iloc.bh = NULL;
4749
4750	ret = __ext4_get_inode_loc(inode, &iloc, 0);
4751	if (ret < 0)
4752		goto bad_inode;
4753	raw_inode = ext4_raw_inode(&iloc);
4754
4755	if ((ino == EXT4_ROOT_INO) && (raw_inode->i_links_count == 0)) {
4756		EXT4_ERROR_INODE(inode, "root inode unallocated");
 
4757		ret = -EFSCORRUPTED;
4758		goto bad_inode;
4759	}
4760
 
 
 
 
 
 
4761	if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE) {
4762		ei->i_extra_isize = le16_to_cpu(raw_inode->i_extra_isize);
4763		if (EXT4_GOOD_OLD_INODE_SIZE + ei->i_extra_isize >
4764			EXT4_INODE_SIZE(inode->i_sb) ||
4765		    (ei->i_extra_isize & 3)) {
4766			EXT4_ERROR_INODE(inode,
4767					 "bad extra_isize %u (inode size %u)",
 
4768					 ei->i_extra_isize,
4769					 EXT4_INODE_SIZE(inode->i_sb));
4770			ret = -EFSCORRUPTED;
4771			goto bad_inode;
4772		}
4773	} else
4774		ei->i_extra_isize = 0;
4775
4776	/* Precompute checksum seed for inode metadata */
4777	if (ext4_has_metadata_csum(sb)) {
4778		struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
4779		__u32 csum;
4780		__le32 inum = cpu_to_le32(inode->i_ino);
4781		__le32 gen = raw_inode->i_generation;
4782		csum = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)&inum,
4783				   sizeof(inum));
4784		ei->i_csum_seed = ext4_chksum(sbi, csum, (__u8 *)&gen,
4785					      sizeof(gen));
4786	}
4787
4788	if (!ext4_inode_csum_verify(inode, raw_inode, ei)) {
4789		EXT4_ERROR_INODE(inode, "checksum invalid");
 
 
 
4790		ret = -EFSBADCRC;
4791		goto bad_inode;
4792	}
4793
4794	inode->i_mode = le16_to_cpu(raw_inode->i_mode);
4795	i_uid = (uid_t)le16_to_cpu(raw_inode->i_uid_low);
4796	i_gid = (gid_t)le16_to_cpu(raw_inode->i_gid_low);
4797	if (ext4_has_feature_project(sb) &&
4798	    EXT4_INODE_SIZE(sb) > EXT4_GOOD_OLD_INODE_SIZE &&
4799	    EXT4_FITS_IN_INODE(raw_inode, ei, i_projid))
4800		i_projid = (projid_t)le32_to_cpu(raw_inode->i_projid);
4801	else
4802		i_projid = EXT4_DEF_PROJID;
4803
4804	if (!(test_opt(inode->i_sb, NO_UID32))) {
4805		i_uid |= le16_to_cpu(raw_inode->i_uid_high) << 16;
4806		i_gid |= le16_to_cpu(raw_inode->i_gid_high) << 16;
4807	}
4808	i_uid_write(inode, i_uid);
4809	i_gid_write(inode, i_gid);
4810	ei->i_projid = make_kprojid(&init_user_ns, i_projid);
4811	set_nlink(inode, le16_to_cpu(raw_inode->i_links_count));
4812
4813	ext4_clear_state_flags(ei);	/* Only relevant on 32-bit archs */
4814	ei->i_inline_off = 0;
4815	ei->i_dir_start_lookup = 0;
4816	ei->i_dtime = le32_to_cpu(raw_inode->i_dtime);
4817	/* We now have enough fields to check if the inode was active or not.
4818	 * This is needed because nfsd might try to access dead inodes
4819	 * the test is that same one that e2fsck uses
4820	 * NeilBrown 1999oct15
4821	 */
4822	if (inode->i_nlink == 0) {
4823		if ((inode->i_mode == 0 ||
4824		     !(EXT4_SB(inode->i_sb)->s_mount_state & EXT4_ORPHAN_FS)) &&
4825		    ino != EXT4_BOOT_LOADER_INO) {
4826			/* this inode is deleted */
4827			ret = -ESTALE;
4828			goto bad_inode;
4829		}
4830		/* The only unlinked inodes we let through here have
4831		 * valid i_mode and are being read by the orphan
4832		 * recovery code: that's fine, we're about to complete
4833		 * the process of deleting those.
4834		 * OR it is the EXT4_BOOT_LOADER_INO which is
4835		 * not initialized on a new filesystem. */
4836	}
4837	ei->i_flags = le32_to_cpu(raw_inode->i_flags);
 
4838	inode->i_blocks = ext4_inode_blocks(raw_inode, ei);
4839	ei->i_file_acl = le32_to_cpu(raw_inode->i_file_acl_lo);
4840	if (ext4_has_feature_64bit(sb))
4841		ei->i_file_acl |=
4842			((__u64)le16_to_cpu(raw_inode->i_file_acl_high)) << 32;
4843	inode->i_size = ext4_isize(sb, raw_inode);
4844	if ((size = i_size_read(inode)) < 0) {
4845		EXT4_ERROR_INODE(inode, "bad i_size value: %lld", size);
 
 
 
 
 
 
 
 
 
 
 
 
 
4846		ret = -EFSCORRUPTED;
4847		goto bad_inode;
4848	}
4849	ei->i_disksize = inode->i_size;
4850#ifdef CONFIG_QUOTA
4851	ei->i_reserved_quota = 0;
4852#endif
4853	inode->i_generation = le32_to_cpu(raw_inode->i_generation);
4854	ei->i_block_group = iloc.block_group;
4855	ei->i_last_alloc_group = ~0;
4856	/*
4857	 * NOTE! The in-memory inode i_data array is in little-endian order
4858	 * even on big-endian machines: we do NOT byteswap the block numbers!
4859	 */
4860	for (block = 0; block < EXT4_N_BLOCKS; block++)
4861		ei->i_data[block] = raw_inode->i_block[block];
4862	INIT_LIST_HEAD(&ei->i_orphan);
 
4863
4864	/*
4865	 * Set transaction id's of transactions that have to be committed
4866	 * to finish f[data]sync. We set them to currently running transaction
4867	 * as we cannot be sure that the inode or some of its metadata isn't
4868	 * part of the transaction - the inode could have been reclaimed and
4869	 * now it is reread from disk.
4870	 */
4871	if (journal) {
4872		transaction_t *transaction;
4873		tid_t tid;
4874
4875		read_lock(&journal->j_state_lock);
4876		if (journal->j_running_transaction)
4877			transaction = journal->j_running_transaction;
4878		else
4879			transaction = journal->j_committing_transaction;
4880		if (transaction)
4881			tid = transaction->t_tid;
4882		else
4883			tid = journal->j_commit_sequence;
4884		read_unlock(&journal->j_state_lock);
4885		ei->i_sync_tid = tid;
4886		ei->i_datasync_tid = tid;
4887	}
4888
4889	if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE) {
4890		if (ei->i_extra_isize == 0) {
4891			/* The extra space is currently unused. Use it. */
4892			BUILD_BUG_ON(sizeof(struct ext4_inode) & 3);
4893			ei->i_extra_isize = sizeof(struct ext4_inode) -
4894					    EXT4_GOOD_OLD_INODE_SIZE;
4895		} else {
4896			ext4_iget_extra_inode(inode, raw_inode, ei);
 
 
4897		}
4898	}
4899
4900	EXT4_INODE_GET_XTIME(i_ctime, inode, raw_inode);
4901	EXT4_INODE_GET_XTIME(i_mtime, inode, raw_inode);
4902	EXT4_INODE_GET_XTIME(i_atime, inode, raw_inode);
4903	EXT4_EINODE_GET_XTIME(i_crtime, ei, raw_inode);
4904
4905	if (likely(!test_opt2(inode->i_sb, HURD_COMPAT))) {
4906		u64 ivers = le32_to_cpu(raw_inode->i_disk_version);
4907
4908		if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE) {
4909			if (EXT4_FITS_IN_INODE(raw_inode, ei, i_version_hi))
4910				ivers |=
4911		    (__u64)(le32_to_cpu(raw_inode->i_version_hi)) << 32;
4912		}
4913		inode_set_iversion_queried(inode, ivers);
4914	}
4915
4916	ret = 0;
4917	if (ei->i_file_acl &&
4918	    !ext4_data_block_valid(EXT4_SB(sb), ei->i_file_acl, 1)) {
4919		EXT4_ERROR_INODE(inode, "bad extended attribute block %llu",
 
4920				 ei->i_file_acl);
4921		ret = -EFSCORRUPTED;
4922		goto bad_inode;
4923	} else if (!ext4_has_inline_data(inode)) {
4924		if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) {
4925			if ((S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
4926			    (S_ISLNK(inode->i_mode) &&
4927			     !ext4_inode_is_fast_symlink(inode))))
4928				/* Validate extent which is part of inode */
 
4929				ret = ext4_ext_check_inode(inode);
4930		} else if (S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
4931			   (S_ISLNK(inode->i_mode) &&
4932			    !ext4_inode_is_fast_symlink(inode))) {
4933			/* Validate block references which are part of inode */
4934			ret = ext4_ind_check_inode(inode);
4935		}
4936	}
4937	if (ret)
4938		goto bad_inode;
4939
4940	if (S_ISREG(inode->i_mode)) {
4941		inode->i_op = &ext4_file_inode_operations;
4942		inode->i_fop = &ext4_file_operations;
4943		ext4_set_aops(inode);
4944	} else if (S_ISDIR(inode->i_mode)) {
4945		inode->i_op = &ext4_dir_inode_operations;
4946		inode->i_fop = &ext4_dir_operations;
4947	} else if (S_ISLNK(inode->i_mode)) {
4948		if (ext4_encrypted_inode(inode)) {
 
 
 
 
 
 
 
 
4949			inode->i_op = &ext4_encrypted_symlink_inode_operations;
4950			ext4_set_aops(inode);
4951		} else if (ext4_inode_is_fast_symlink(inode)) {
4952			inode->i_link = (char *)ei->i_data;
4953			inode->i_op = &ext4_fast_symlink_inode_operations;
4954			nd_terminate_link(ei->i_data, inode->i_size,
4955				sizeof(ei->i_data) - 1);
4956		} else {
4957			inode->i_op = &ext4_symlink_inode_operations;
4958			ext4_set_aops(inode);
4959		}
4960		inode_nohighmem(inode);
4961	} else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode) ||
4962	      S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode)) {
4963		inode->i_op = &ext4_special_inode_operations;
4964		if (raw_inode->i_block[0])
4965			init_special_inode(inode, inode->i_mode,
4966			   old_decode_dev(le32_to_cpu(raw_inode->i_block[0])));
4967		else
4968			init_special_inode(inode, inode->i_mode,
4969			   new_decode_dev(le32_to_cpu(raw_inode->i_block[1])));
4970	} else if (ino == EXT4_BOOT_LOADER_INO) {
4971		make_bad_inode(inode);
4972	} else {
4973		ret = -EFSCORRUPTED;
4974		EXT4_ERROR_INODE(inode, "bogus i_mode (%o)", inode->i_mode);
 
4975		goto bad_inode;
4976	}
 
 
 
4977	brelse(iloc.bh);
4978	ext4_set_inode_flags(inode);
4979
4980	unlock_new_inode(inode);
4981	return inode;
4982
4983bad_inode:
4984	brelse(iloc.bh);
4985	iget_failed(inode);
4986	return ERR_PTR(ret);
4987}
4988
4989struct inode *ext4_iget_normal(struct super_block *sb, unsigned long ino)
4990{
4991	if (ino < EXT4_FIRST_INO(sb) && ino != EXT4_ROOT_INO)
4992		return ERR_PTR(-EFSCORRUPTED);
4993	return ext4_iget(sb, ino);
4994}
4995
4996static int ext4_inode_blocks_set(handle_t *handle,
4997				struct ext4_inode *raw_inode,
4998				struct ext4_inode_info *ei)
4999{
5000	struct inode *inode = &(ei->vfs_inode);
5001	u64 i_blocks = inode->i_blocks;
5002	struct super_block *sb = inode->i_sb;
5003
5004	if (i_blocks <= ~0U) {
5005		/*
5006		 * i_blocks can be represented in a 32 bit variable
5007		 * as multiple of 512 bytes
5008		 */
5009		raw_inode->i_blocks_lo   = cpu_to_le32(i_blocks);
5010		raw_inode->i_blocks_high = 0;
5011		ext4_clear_inode_flag(inode, EXT4_INODE_HUGE_FILE);
5012		return 0;
5013	}
5014	if (!ext4_has_feature_huge_file(sb))
5015		return -EFBIG;
5016
5017	if (i_blocks <= 0xffffffffffffULL) {
5018		/*
5019		 * i_blocks can be represented in a 48 bit variable
5020		 * as multiple of 512 bytes
5021		 */
5022		raw_inode->i_blocks_lo   = cpu_to_le32(i_blocks);
5023		raw_inode->i_blocks_high = cpu_to_le16(i_blocks >> 32);
5024		ext4_clear_inode_flag(inode, EXT4_INODE_HUGE_FILE);
5025	} else {
5026		ext4_set_inode_flag(inode, EXT4_INODE_HUGE_FILE);
5027		/* i_block is stored in file system block size */
5028		i_blocks = i_blocks >> (inode->i_blkbits - 9);
5029		raw_inode->i_blocks_lo   = cpu_to_le32(i_blocks);
5030		raw_inode->i_blocks_high = cpu_to_le16(i_blocks >> 32);
5031	}
5032	return 0;
5033}
5034
5035struct other_inode {
5036	unsigned long		orig_ino;
5037	struct ext4_inode	*raw_inode;
5038};
5039
5040static int other_inode_match(struct inode * inode, unsigned long ino,
5041			     void *data)
5042{
5043	struct other_inode *oi = (struct other_inode *) data;
 
 
 
 
 
 
 
5044
5045	if ((inode->i_ino != ino) ||
5046	    (inode->i_state & (I_FREEING | I_WILL_FREE | I_NEW |
5047			       I_DIRTY_INODE)) ||
5048	    ((inode->i_state & I_DIRTY_TIME) == 0))
5049		return 0;
5050	spin_lock(&inode->i_lock);
5051	if (((inode->i_state & (I_FREEING | I_WILL_FREE | I_NEW |
5052				I_DIRTY_INODE)) == 0) &&
5053	    (inode->i_state & I_DIRTY_TIME)) {
5054		struct ext4_inode_info	*ei = EXT4_I(inode);
5055
5056		inode->i_state &= ~(I_DIRTY_TIME | I_DIRTY_TIME_EXPIRED);
5057		spin_unlock(&inode->i_lock);
5058
5059		spin_lock(&ei->i_raw_lock);
5060		EXT4_INODE_SET_XTIME(i_ctime, inode, oi->raw_inode);
5061		EXT4_INODE_SET_XTIME(i_mtime, inode, oi->raw_inode);
5062		EXT4_INODE_SET_XTIME(i_atime, inode, oi->raw_inode);
5063		ext4_inode_csum_set(inode, oi->raw_inode, ei);
5064		spin_unlock(&ei->i_raw_lock);
5065		trace_ext4_other_inode_update_time(inode, oi->orig_ino);
5066		return -1;
5067	}
5068	spin_unlock(&inode->i_lock);
5069	return -1;
5070}
5071
5072/*
5073 * Opportunistically update the other time fields for other inodes in
5074 * the same inode table block.
5075 */
5076static void ext4_update_other_inodes_time(struct super_block *sb,
5077					  unsigned long orig_ino, char *buf)
5078{
5079	struct other_inode oi;
5080	unsigned long ino;
5081	int i, inodes_per_block = EXT4_SB(sb)->s_inodes_per_block;
5082	int inode_size = EXT4_INODE_SIZE(sb);
5083
5084	oi.orig_ino = orig_ino;
5085	/*
5086	 * Calculate the first inode in the inode table block.  Inode
5087	 * numbers are one-based.  That is, the first inode in a block
5088	 * (assuming 4k blocks and 256 byte inodes) is (n*16 + 1).
5089	 */
5090	ino = ((orig_ino - 1) & ~(inodes_per_block - 1)) + 1;
 
5091	for (i = 0; i < inodes_per_block; i++, ino++, buf += inode_size) {
5092		if (ino == orig_ino)
5093			continue;
5094		oi.raw_inode = (struct ext4_inode *) buf;
5095		(void) find_inode_nowait(sb, ino, other_inode_match, &oi);
5096	}
 
5097}
5098
5099/*
5100 * Post the struct inode info into an on-disk inode location in the
5101 * buffer-cache.  This gobbles the caller's reference to the
5102 * buffer_head in the inode location struct.
5103 *
5104 * The caller must have write access to iloc->bh.
5105 */
5106static int ext4_do_update_inode(handle_t *handle,
5107				struct inode *inode,
5108				struct ext4_iloc *iloc)
5109{
5110	struct ext4_inode *raw_inode = ext4_raw_inode(iloc);
5111	struct ext4_inode_info *ei = EXT4_I(inode);
5112	struct buffer_head *bh = iloc->bh;
5113	struct super_block *sb = inode->i_sb;
5114	int err = 0, rc, block;
5115	int need_datasync = 0, set_large_file = 0;
5116	uid_t i_uid;
5117	gid_t i_gid;
5118	projid_t i_projid;
5119
5120	spin_lock(&ei->i_raw_lock);
5121
5122	/* For fields not tracked in the in-memory inode,
5123	 * initialise them to zero for new inodes. */
5124	if (ext4_test_inode_state(inode, EXT4_STATE_NEW))
5125		memset(raw_inode, 0, EXT4_SB(inode->i_sb)->s_inode_size);
5126
 
 
 
 
 
 
5127	raw_inode->i_mode = cpu_to_le16(inode->i_mode);
5128	i_uid = i_uid_read(inode);
5129	i_gid = i_gid_read(inode);
5130	i_projid = from_kprojid(&init_user_ns, ei->i_projid);
5131	if (!(test_opt(inode->i_sb, NO_UID32))) {
5132		raw_inode->i_uid_low = cpu_to_le16(low_16_bits(i_uid));
5133		raw_inode->i_gid_low = cpu_to_le16(low_16_bits(i_gid));
5134/*
5135 * Fix up interoperability with old kernels. Otherwise, old inodes get
5136 * re-used with the upper 16 bits of the uid/gid intact
5137 */
5138		if (ei->i_dtime && list_empty(&ei->i_orphan)) {
5139			raw_inode->i_uid_high = 0;
5140			raw_inode->i_gid_high = 0;
5141		} else {
5142			raw_inode->i_uid_high =
5143				cpu_to_le16(high_16_bits(i_uid));
5144			raw_inode->i_gid_high =
5145				cpu_to_le16(high_16_bits(i_gid));
5146		}
5147	} else {
5148		raw_inode->i_uid_low = cpu_to_le16(fs_high2lowuid(i_uid));
5149		raw_inode->i_gid_low = cpu_to_le16(fs_high2lowgid(i_gid));
5150		raw_inode->i_uid_high = 0;
5151		raw_inode->i_gid_high = 0;
5152	}
5153	raw_inode->i_links_count = cpu_to_le16(inode->i_nlink);
5154
5155	EXT4_INODE_SET_XTIME(i_ctime, inode, raw_inode);
5156	EXT4_INODE_SET_XTIME(i_mtime, inode, raw_inode);
5157	EXT4_INODE_SET_XTIME(i_atime, inode, raw_inode);
5158	EXT4_EINODE_SET_XTIME(i_crtime, ei, raw_inode);
5159
5160	err = ext4_inode_blocks_set(handle, raw_inode, ei);
5161	if (err) {
5162		spin_unlock(&ei->i_raw_lock);
5163		goto out_brelse;
5164	}
5165	raw_inode->i_dtime = cpu_to_le32(ei->i_dtime);
5166	raw_inode->i_flags = cpu_to_le32(ei->i_flags & 0xFFFFFFFF);
5167	if (likely(!test_opt2(inode->i_sb, HURD_COMPAT)))
5168		raw_inode->i_file_acl_high =
5169			cpu_to_le16(ei->i_file_acl >> 32);
5170	raw_inode->i_file_acl_lo = cpu_to_le32(ei->i_file_acl);
5171	if (ei->i_disksize != ext4_isize(inode->i_sb, raw_inode)) {
5172		ext4_isize_set(raw_inode, ei->i_disksize);
5173		need_datasync = 1;
5174	}
5175	if (ei->i_disksize > 0x7fffffffULL) {
5176		if (!ext4_has_feature_large_file(sb) ||
5177				EXT4_SB(sb)->s_es->s_rev_level ==
5178		    cpu_to_le32(EXT4_GOOD_OLD_REV))
5179			set_large_file = 1;
5180	}
5181	raw_inode->i_generation = cpu_to_le32(inode->i_generation);
5182	if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode)) {
5183		if (old_valid_dev(inode->i_rdev)) {
5184			raw_inode->i_block[0] =
5185				cpu_to_le32(old_encode_dev(inode->i_rdev));
5186			raw_inode->i_block[1] = 0;
5187		} else {
5188			raw_inode->i_block[0] = 0;
5189			raw_inode->i_block[1] =
5190				cpu_to_le32(new_encode_dev(inode->i_rdev));
5191			raw_inode->i_block[2] = 0;
5192		}
5193	} else if (!ext4_has_inline_data(inode)) {
5194		for (block = 0; block < EXT4_N_BLOCKS; block++)
5195			raw_inode->i_block[block] = ei->i_data[block];
5196	}
5197
5198	if (likely(!test_opt2(inode->i_sb, HURD_COMPAT))) {
5199		u64 ivers = inode_peek_iversion(inode);
5200
5201		raw_inode->i_disk_version = cpu_to_le32(ivers);
5202		if (ei->i_extra_isize) {
5203			if (EXT4_FITS_IN_INODE(raw_inode, ei, i_version_hi))
5204				raw_inode->i_version_hi =
5205					cpu_to_le32(ivers >> 32);
5206			raw_inode->i_extra_isize =
5207				cpu_to_le16(ei->i_extra_isize);
5208		}
5209	}
5210
5211	BUG_ON(!ext4_has_feature_project(inode->i_sb) &&
5212	       i_projid != EXT4_DEF_PROJID);
5213
5214	if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE &&
5215	    EXT4_FITS_IN_INODE(raw_inode, ei, i_projid))
5216		raw_inode->i_projid = cpu_to_le32(i_projid);
5217
5218	ext4_inode_csum_set(inode, raw_inode, ei);
5219	spin_unlock(&ei->i_raw_lock);
5220	if (inode->i_sb->s_flags & SB_LAZYTIME)
5221		ext4_update_other_inodes_time(inode->i_sb, inode->i_ino,
5222					      bh->b_data);
5223
5224	BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
5225	rc = ext4_handle_dirty_metadata(handle, NULL, bh);
5226	if (!err)
5227		err = rc;
5228	ext4_clear_inode_state(inode, EXT4_STATE_NEW);
5229	if (set_large_file) {
5230		BUFFER_TRACE(EXT4_SB(sb)->s_sbh, "get write access");
5231		err = ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh);
5232		if (err)
5233			goto out_brelse;
5234		ext4_update_dynamic_rev(sb);
5235		ext4_set_feature_large_file(sb);
 
 
5236		ext4_handle_sync(handle);
5237		err = ext4_handle_dirty_super(handle, sb);
 
5238	}
5239	ext4_update_inode_fsync_trans(handle, inode, need_datasync);
5240out_brelse:
5241	brelse(bh);
5242	ext4_std_error(inode->i_sb, err);
5243	return err;
5244}
5245
5246/*
5247 * ext4_write_inode()
5248 *
5249 * We are called from a few places:
5250 *
5251 * - Within generic_file_aio_write() -> generic_write_sync() for O_SYNC files.
5252 *   Here, there will be no transaction running. We wait for any running
5253 *   transaction to commit.
5254 *
5255 * - Within flush work (sys_sync(), kupdate and such).
5256 *   We wait on commit, if told to.
5257 *
5258 * - Within iput_final() -> write_inode_now()
5259 *   We wait on commit, if told to.
5260 *
5261 * In all cases it is actually safe for us to return without doing anything,
5262 * because the inode has been copied into a raw inode buffer in
5263 * ext4_mark_inode_dirty().  This is a correctness thing for WB_SYNC_ALL
5264 * writeback.
5265 *
5266 * Note that we are absolutely dependent upon all inode dirtiers doing the
5267 * right thing: they *must* call mark_inode_dirty() after dirtying info in
5268 * which we are interested.
5269 *
5270 * It would be a bug for them to not do this.  The code:
5271 *
5272 *	mark_inode_dirty(inode)
5273 *	stuff();
5274 *	inode->i_size = expr;
5275 *
5276 * is in error because write_inode() could occur while `stuff()' is running,
5277 * and the new i_size will be lost.  Plus the inode will no longer be on the
5278 * superblock's dirty inode list.
5279 */
5280int ext4_write_inode(struct inode *inode, struct writeback_control *wbc)
5281{
5282	int err;
5283
5284	if (WARN_ON_ONCE(current->flags & PF_MEMALLOC))
 
5285		return 0;
5286
 
 
 
5287	if (EXT4_SB(inode->i_sb)->s_journal) {
5288		if (ext4_journal_current_handle()) {
5289			jbd_debug(1, "called recursively, non-PF_MEMALLOC!\n");
5290			dump_stack();
5291			return -EIO;
5292		}
5293
5294		/*
5295		 * No need to force transaction in WB_SYNC_NONE mode. Also
5296		 * ext4_sync_fs() will force the commit after everything is
5297		 * written.
5298		 */
5299		if (wbc->sync_mode != WB_SYNC_ALL || wbc->for_sync)
5300			return 0;
5301
5302		err = ext4_force_commit(inode->i_sb);
 
5303	} else {
5304		struct ext4_iloc iloc;
5305
5306		err = __ext4_get_inode_loc(inode, &iloc, 0);
5307		if (err)
5308			return err;
5309		/*
5310		 * sync(2) will flush the whole buffer cache. No need to do
5311		 * it here separately for each inode.
5312		 */
5313		if (wbc->sync_mode == WB_SYNC_ALL && !wbc->for_sync)
5314			sync_dirty_buffer(iloc.bh);
5315		if (buffer_req(iloc.bh) && !buffer_uptodate(iloc.bh)) {
5316			EXT4_ERROR_INODE_BLOCK(inode, iloc.bh->b_blocknr,
5317					 "IO error syncing inode");
5318			err = -EIO;
5319		}
5320		brelse(iloc.bh);
5321	}
5322	return err;
5323}
5324
5325/*
5326 * In data=journal mode ext4_journalled_invalidatepage() may fail to invalidate
5327 * buffers that are attached to a page stradding i_size and are undergoing
5328 * commit. In that case we have to wait for commit to finish and try again.
5329 */
5330static void ext4_wait_for_tail_page_commit(struct inode *inode)
5331{
5332	struct page *page;
5333	unsigned offset;
5334	journal_t *journal = EXT4_SB(inode->i_sb)->s_journal;
5335	tid_t commit_tid = 0;
5336	int ret;
5337
5338	offset = inode->i_size & (PAGE_SIZE - 1);
5339	/*
5340	 * All buffers in the last page remain valid? Then there's nothing to
5341	 * do. We do the check mainly to optimize the common PAGE_SIZE ==
5342	 * blocksize case
 
 
 
 
5343	 */
5344	if (offset > PAGE_SIZE - i_blocksize(inode))
5345		return;
5346	while (1) {
5347		page = find_lock_page(inode->i_mapping,
5348				      inode->i_size >> PAGE_SHIFT);
5349		if (!page)
5350			return;
5351		ret = __ext4_journalled_invalidatepage(page, offset,
5352						PAGE_SIZE - offset);
5353		unlock_page(page);
5354		put_page(page);
5355		if (ret != -EBUSY)
5356			return;
5357		commit_tid = 0;
5358		read_lock(&journal->j_state_lock);
5359		if (journal->j_committing_transaction)
5360			commit_tid = journal->j_committing_transaction->t_tid;
5361		read_unlock(&journal->j_state_lock);
5362		if (commit_tid)
5363			jbd2_log_wait_commit(journal, commit_tid);
5364	}
5365}
5366
5367/*
5368 * ext4_setattr()
5369 *
5370 * Called from notify_change.
5371 *
5372 * We want to trap VFS attempts to truncate the file as soon as
5373 * possible.  In particular, we want to make sure that when the VFS
5374 * shrinks i_size, we put the inode on the orphan list and modify
5375 * i_disksize immediately, so that during the subsequent flushing of
5376 * dirty pages and freeing of disk blocks, we can guarantee that any
5377 * commit will leave the blocks being flushed in an unused state on
5378 * disk.  (On recovery, the inode will get truncated and the blocks will
5379 * be freed, so we have a strong guarantee that no future commit will
5380 * leave these blocks visible to the user.)
5381 *
5382 * Another thing we have to assure is that if we are in ordered mode
5383 * and inode is still attached to the committing transaction, we must
5384 * we start writeout of all the dirty pages which are being truncated.
5385 * This way we are sure that all the data written in the previous
5386 * transaction are already on disk (truncate waits for pages under
5387 * writeback).
5388 *
5389 * Called with inode->i_mutex down.
5390 */
5391int ext4_setattr(struct dentry *dentry, struct iattr *attr)
 
5392{
5393	struct inode *inode = d_inode(dentry);
5394	int error, rc = 0;
5395	int orphan = 0;
5396	const unsigned int ia_valid = attr->ia_valid;
5397
5398	if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb))))
5399		return -EIO;
5400
5401	error = setattr_prepare(dentry, attr);
 
 
 
 
 
 
 
 
5402	if (error)
5403		return error;
5404
5405	error = fscrypt_prepare_setattr(dentry, attr);
5406	if (error)
5407		return error;
5408
 
 
 
 
5409	if (is_quota_modification(inode, attr)) {
5410		error = dquot_initialize(inode);
5411		if (error)
5412			return error;
5413	}
 
5414	if ((ia_valid & ATTR_UID && !uid_eq(attr->ia_uid, inode->i_uid)) ||
5415	    (ia_valid & ATTR_GID && !gid_eq(attr->ia_gid, inode->i_gid))) {
5416		handle_t *handle;
5417
5418		/* (user+group)*(old+new) structure, inode write (sb,
5419		 * inode block, ? - but truncate inode update has it) */
5420		handle = ext4_journal_start(inode, EXT4_HT_QUOTA,
5421			(EXT4_MAXQUOTAS_INIT_BLOCKS(inode->i_sb) +
5422			 EXT4_MAXQUOTAS_DEL_BLOCKS(inode->i_sb)) + 3);
5423		if (IS_ERR(handle)) {
5424			error = PTR_ERR(handle);
5425			goto err_out;
5426		}
5427
5428		/* dquot_transfer() calls back ext4_get_inode_usage() which
5429		 * counts xattr inode references.
5430		 */
5431		down_read(&EXT4_I(inode)->xattr_sem);
5432		error = dquot_transfer(inode, attr);
5433		up_read(&EXT4_I(inode)->xattr_sem);
5434
5435		if (error) {
5436			ext4_journal_stop(handle);
 
5437			return error;
5438		}
5439		/* Update corresponding info in inode so that everything is in
5440		 * one transaction */
5441		if (attr->ia_valid & ATTR_UID)
5442			inode->i_uid = attr->ia_uid;
5443		if (attr->ia_valid & ATTR_GID)
5444			inode->i_gid = attr->ia_gid;
5445		error = ext4_mark_inode_dirty(handle, inode);
5446		ext4_journal_stop(handle);
 
 
 
 
5447	}
5448
5449	if (attr->ia_valid & ATTR_SIZE) {
5450		handle_t *handle;
5451		loff_t oldsize = inode->i_size;
5452		int shrink = (attr->ia_size <= inode->i_size);
5453
5454		if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) {
5455			struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
5456
5457			if (attr->ia_size > sbi->s_bitmap_maxbytes)
 
5458				return -EFBIG;
 
5459		}
5460		if (!S_ISREG(inode->i_mode))
 
5461			return -EINVAL;
 
5462
5463		if (IS_I_VERSION(inode) && attr->ia_size != inode->i_size)
5464			inode_inc_iversion(inode);
5465
5466		if (ext4_should_order_data(inode) &&
5467		    (attr->ia_size < inode->i_size)) {
5468			error = ext4_begin_ordered_truncate(inode,
5469							    attr->ia_size);
5470			if (error)
5471				goto err_out;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
5472		}
 
5473		if (attr->ia_size != inode->i_size) {
5474			handle = ext4_journal_start(inode, EXT4_HT_INODE, 3);
5475			if (IS_ERR(handle)) {
5476				error = PTR_ERR(handle);
5477				goto err_out;
5478			}
5479			if (ext4_handle_valid(handle) && shrink) {
5480				error = ext4_orphan_add(handle, inode);
5481				orphan = 1;
5482			}
5483			/*
5484			 * Update c/mtime on truncate up, ext4_truncate() will
5485			 * update c/mtime in shrink case below
5486			 */
5487			if (!shrink) {
5488				inode->i_mtime = current_time(inode);
5489				inode->i_ctime = inode->i_mtime;
5490			}
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
5491			down_write(&EXT4_I(inode)->i_data_sem);
5492			EXT4_I(inode)->i_disksize = attr->ia_size;
5493			rc = ext4_mark_inode_dirty(handle, inode);
5494			if (!error)
5495				error = rc;
5496			/*
5497			 * We have to update i_size under i_data_sem together
5498			 * with i_disksize to avoid races with writeback code
5499			 * running ext4_wb_update_i_disksize().
5500			 */
5501			if (!error)
5502				i_size_write(inode, attr->ia_size);
5503			up_write(&EXT4_I(inode)->i_data_sem);
5504			ext4_journal_stop(handle);
5505			if (error) {
5506				if (orphan)
5507					ext4_orphan_del(NULL, inode);
5508				goto err_out;
 
 
 
5509			}
5510		}
5511		if (!shrink)
5512			pagecache_isize_extended(inode, oldsize, inode->i_size);
5513
5514		/*
5515		 * Blocks are going to be removed from the inode. Wait
5516		 * for dio in flight.  Temporarily disable
5517		 * dioread_nolock to prevent livelock.
5518		 */
5519		if (orphan) {
5520			if (!ext4_should_journal_data(inode)) {
5521				inode_dio_wait(inode);
5522			} else
5523				ext4_wait_for_tail_page_commit(inode);
5524		}
5525		down_write(&EXT4_I(inode)->i_mmap_sem);
5526		/*
5527		 * Truncate pagecache after we've waited for commit
5528		 * in data=journal mode to make pages freeable.
5529		 */
5530		truncate_pagecache(inode, inode->i_size);
5531		if (shrink) {
 
 
 
 
5532			rc = ext4_truncate(inode);
5533			if (rc)
5534				error = rc;
5535		}
 
5536		up_write(&EXT4_I(inode)->i_mmap_sem);
5537	}
5538
5539	if (!error) {
5540		setattr_copy(inode, attr);
5541		mark_inode_dirty(inode);
5542	}
5543
5544	/*
5545	 * If the call to ext4_truncate failed to get a transaction handle at
5546	 * all, we need to clean up the in-core orphan list manually.
5547	 */
5548	if (orphan && inode->i_nlink)
5549		ext4_orphan_del(NULL, inode);
5550
5551	if (!error && (ia_valid & ATTR_MODE))
5552		rc = posix_acl_chmod(inode, inode->i_mode);
5553
5554err_out:
5555	ext4_std_error(inode->i_sb, error);
 
5556	if (!error)
5557		error = rc;
 
5558	return error;
5559}
5560
5561int ext4_getattr(const struct path *path, struct kstat *stat,
5562		 u32 request_mask, unsigned int query_flags)
5563{
5564	struct inode *inode = d_inode(path->dentry);
5565	struct ext4_inode *raw_inode;
5566	struct ext4_inode_info *ei = EXT4_I(inode);
5567	unsigned int flags;
5568
5569	if (EXT4_FITS_IN_INODE(raw_inode, ei, i_crtime)) {
 
5570		stat->result_mask |= STATX_BTIME;
5571		stat->btime.tv_sec = ei->i_crtime.tv_sec;
5572		stat->btime.tv_nsec = ei->i_crtime.tv_nsec;
5573	}
5574
5575	flags = ei->i_flags & EXT4_FL_USER_VISIBLE;
5576	if (flags & EXT4_APPEND_FL)
5577		stat->attributes |= STATX_ATTR_APPEND;
5578	if (flags & EXT4_COMPR_FL)
5579		stat->attributes |= STATX_ATTR_COMPRESSED;
5580	if (flags & EXT4_ENCRYPT_FL)
5581		stat->attributes |= STATX_ATTR_ENCRYPTED;
5582	if (flags & EXT4_IMMUTABLE_FL)
5583		stat->attributes |= STATX_ATTR_IMMUTABLE;
5584	if (flags & EXT4_NODUMP_FL)
5585		stat->attributes |= STATX_ATTR_NODUMP;
 
 
5586
5587	stat->attributes_mask |= (STATX_ATTR_APPEND |
5588				  STATX_ATTR_COMPRESSED |
5589				  STATX_ATTR_ENCRYPTED |
5590				  STATX_ATTR_IMMUTABLE |
5591				  STATX_ATTR_NODUMP);
 
5592
5593	generic_fillattr(inode, stat);
5594	return 0;
5595}
5596
5597int ext4_file_getattr(const struct path *path, struct kstat *stat,
 
5598		      u32 request_mask, unsigned int query_flags)
5599{
5600	struct inode *inode = d_inode(path->dentry);
5601	u64 delalloc_blocks;
5602
5603	ext4_getattr(path, stat, request_mask, query_flags);
5604
5605	/*
5606	 * If there is inline data in the inode, the inode will normally not
5607	 * have data blocks allocated (it may have an external xattr block).
5608	 * Report at least one sector for such files, so tools like tar, rsync,
5609	 * others don't incorrectly think the file is completely sparse.
5610	 */
5611	if (unlikely(ext4_has_inline_data(inode)))
5612		stat->blocks += (stat->size + 511) >> 9;
5613
5614	/*
5615	 * We can't update i_blocks if the block allocation is delayed
5616	 * otherwise in the case of system crash before the real block
5617	 * allocation is done, we will have i_blocks inconsistent with
5618	 * on-disk file blocks.
5619	 * We always keep i_blocks updated together with real
5620	 * allocation. But to not confuse with user, stat
5621	 * will return the blocks that include the delayed allocation
5622	 * blocks for this file.
5623	 */
5624	delalloc_blocks = EXT4_C2B(EXT4_SB(inode->i_sb),
5625				   EXT4_I(inode)->i_reserved_data_blocks);
5626	stat->blocks += delalloc_blocks << (inode->i_sb->s_blocksize_bits - 9);
5627	return 0;
5628}
5629
5630static int ext4_index_trans_blocks(struct inode *inode, int lblocks,
5631				   int pextents)
5632{
5633	if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
5634		return ext4_ind_trans_blocks(inode, lblocks);
5635	return ext4_ext_index_trans_blocks(inode, pextents);
5636}
5637
5638/*
5639 * Account for index blocks, block groups bitmaps and block group
5640 * descriptor blocks if modify datablocks and index blocks
5641 * worse case, the indexs blocks spread over different block groups
5642 *
5643 * If datablocks are discontiguous, they are possible to spread over
5644 * different block groups too. If they are contiguous, with flexbg,
5645 * they could still across block group boundary.
5646 *
5647 * Also account for superblock, inode, quota and xattr blocks
5648 */
5649static int ext4_meta_trans_blocks(struct inode *inode, int lblocks,
5650				  int pextents)
5651{
5652	ext4_group_t groups, ngroups = ext4_get_groups_count(inode->i_sb);
5653	int gdpblocks;
5654	int idxblocks;
5655	int ret = 0;
5656
5657	/*
5658	 * How many index blocks need to touch to map @lblocks logical blocks
5659	 * to @pextents physical extents?
5660	 */
5661	idxblocks = ext4_index_trans_blocks(inode, lblocks, pextents);
5662
5663	ret = idxblocks;
5664
5665	/*
5666	 * Now let's see how many group bitmaps and group descriptors need
5667	 * to account
5668	 */
5669	groups = idxblocks + pextents;
5670	gdpblocks = groups;
5671	if (groups > ngroups)
5672		groups = ngroups;
5673	if (groups > EXT4_SB(inode->i_sb)->s_gdb_count)
5674		gdpblocks = EXT4_SB(inode->i_sb)->s_gdb_count;
5675
5676	/* bitmaps and block group descriptor blocks */
5677	ret += groups + gdpblocks;
5678
5679	/* Blocks for super block, inode, quota and xattr blocks */
5680	ret += EXT4_META_TRANS_BLOCKS(inode->i_sb);
5681
5682	return ret;
5683}
5684
5685/*
5686 * Calculate the total number of credits to reserve to fit
5687 * the modification of a single pages into a single transaction,
5688 * which may include multiple chunks of block allocations.
5689 *
5690 * This could be called via ext4_write_begin()
5691 *
5692 * We need to consider the worse case, when
5693 * one new block per extent.
5694 */
5695int ext4_writepage_trans_blocks(struct inode *inode)
5696{
5697	int bpp = ext4_journal_blocks_per_page(inode);
5698	int ret;
5699
5700	ret = ext4_meta_trans_blocks(inode, bpp, bpp);
5701
5702	/* Account for data blocks for journalled mode */
5703	if (ext4_should_journal_data(inode))
5704		ret += bpp;
5705	return ret;
5706}
5707
5708/*
5709 * Calculate the journal credits for a chunk of data modification.
5710 *
5711 * This is called from DIO, fallocate or whoever calling
5712 * ext4_map_blocks() to map/allocate a chunk of contiguous disk blocks.
5713 *
5714 * journal buffers for data blocks are not included here, as DIO
5715 * and fallocate do no need to journal data buffers.
5716 */
5717int ext4_chunk_trans_blocks(struct inode *inode, int nrblocks)
5718{
5719	return ext4_meta_trans_blocks(inode, nrblocks, 1);
5720}
5721
5722/*
5723 * The caller must have previously called ext4_reserve_inode_write().
5724 * Give this, we know that the caller already has write access to iloc->bh.
5725 */
5726int ext4_mark_iloc_dirty(handle_t *handle,
5727			 struct inode *inode, struct ext4_iloc *iloc)
5728{
5729	int err = 0;
5730
5731	if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb))))
 
5732		return -EIO;
 
 
5733
5734	if (IS_I_VERSION(inode))
5735		inode_inc_iversion(inode);
5736
5737	/* the do_update_inode consumes one bh->b_count */
5738	get_bh(iloc->bh);
5739
5740	/* ext4_do_update_inode() does jbd2_journal_dirty_metadata */
5741	err = ext4_do_update_inode(handle, inode, iloc);
5742	put_bh(iloc->bh);
5743	return err;
5744}
5745
5746/*
5747 * On success, We end up with an outstanding reference count against
5748 * iloc->bh.  This _must_ be cleaned up later.
5749 */
5750
5751int
5752ext4_reserve_inode_write(handle_t *handle, struct inode *inode,
5753			 struct ext4_iloc *iloc)
5754{
5755	int err;
5756
5757	if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb))))
5758		return -EIO;
5759
5760	err = ext4_get_inode_loc(inode, iloc);
5761	if (!err) {
5762		BUFFER_TRACE(iloc->bh, "get_write_access");
5763		err = ext4_journal_get_write_access(handle, iloc->bh);
5764		if (err) {
5765			brelse(iloc->bh);
5766			iloc->bh = NULL;
5767		}
5768	}
5769	ext4_std_error(inode->i_sb, err);
5770	return err;
5771}
5772
5773static int __ext4_expand_extra_isize(struct inode *inode,
5774				     unsigned int new_extra_isize,
5775				     struct ext4_iloc *iloc,
5776				     handle_t *handle, int *no_expand)
5777{
5778	struct ext4_inode *raw_inode;
5779	struct ext4_xattr_ibody_header *header;
 
 
5780	int error;
5781
 
 
 
 
 
 
 
 
 
 
 
 
 
5782	raw_inode = ext4_raw_inode(iloc);
5783
5784	header = IHDR(inode, raw_inode);
5785
5786	/* No extended attributes present */
5787	if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR) ||
5788	    header->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC)) {
5789		memset((void *)raw_inode + EXT4_GOOD_OLD_INODE_SIZE +
5790		       EXT4_I(inode)->i_extra_isize, 0,
5791		       new_extra_isize - EXT4_I(inode)->i_extra_isize);
5792		EXT4_I(inode)->i_extra_isize = new_extra_isize;
5793		return 0;
5794	}
5795
5796	/* try to expand with EAs present */
5797	error = ext4_expand_extra_isize_ea(inode, new_extra_isize,
5798					   raw_inode, handle);
5799	if (error) {
5800		/*
5801		 * Inode size expansion failed; don't try again
5802		 */
5803		*no_expand = 1;
5804	}
5805
5806	return error;
5807}
5808
5809/*
5810 * Expand an inode by new_extra_isize bytes.
5811 * Returns 0 on success or negative error number on failure.
5812 */
5813static int ext4_try_to_expand_extra_isize(struct inode *inode,
5814					  unsigned int new_extra_isize,
5815					  struct ext4_iloc iloc,
5816					  handle_t *handle)
5817{
5818	int no_expand;
5819	int error;
5820
5821	if (ext4_test_inode_state(inode, EXT4_STATE_NO_EXPAND))
5822		return -EOVERFLOW;
5823
5824	/*
5825	 * In nojournal mode, we can immediately attempt to expand
5826	 * the inode.  When journaled, we first need to obtain extra
5827	 * buffer credits since we may write into the EA block
5828	 * with this same handle. If journal_extend fails, then it will
5829	 * only result in a minor loss of functionality for that inode.
5830	 * If this is felt to be critical, then e2fsck should be run to
5831	 * force a large enough s_min_extra_isize.
5832	 */
5833	if (ext4_handle_valid(handle) &&
5834	    jbd2_journal_extend(handle,
5835				EXT4_DATA_TRANS_BLOCKS(inode->i_sb)) != 0)
5836		return -ENOSPC;
5837
5838	if (ext4_write_trylock_xattr(inode, &no_expand) == 0)
5839		return -EBUSY;
5840
5841	error = __ext4_expand_extra_isize(inode, new_extra_isize, &iloc,
5842					  handle, &no_expand);
5843	ext4_write_unlock_xattr(inode, &no_expand);
5844
5845	return error;
5846}
5847
5848int ext4_expand_extra_isize(struct inode *inode,
5849			    unsigned int new_extra_isize,
5850			    struct ext4_iloc *iloc)
5851{
5852	handle_t *handle;
5853	int no_expand;
5854	int error, rc;
5855
5856	if (ext4_test_inode_state(inode, EXT4_STATE_NO_EXPAND)) {
5857		brelse(iloc->bh);
5858		return -EOVERFLOW;
5859	}
5860
5861	handle = ext4_journal_start(inode, EXT4_HT_INODE,
5862				    EXT4_DATA_TRANS_BLOCKS(inode->i_sb));
5863	if (IS_ERR(handle)) {
5864		error = PTR_ERR(handle);
5865		brelse(iloc->bh);
5866		return error;
5867	}
5868
5869	ext4_write_lock_xattr(inode, &no_expand);
5870
5871	BUFFER_TRACE(iloc.bh, "get_write_access");
5872	error = ext4_journal_get_write_access(handle, iloc->bh);
5873	if (error) {
5874		brelse(iloc->bh);
5875		goto out_stop;
5876	}
5877
5878	error = __ext4_expand_extra_isize(inode, new_extra_isize, iloc,
5879					  handle, &no_expand);
5880
5881	rc = ext4_mark_iloc_dirty(handle, inode, iloc);
5882	if (!error)
5883		error = rc;
5884
 
5885	ext4_write_unlock_xattr(inode, &no_expand);
5886out_stop:
5887	ext4_journal_stop(handle);
5888	return error;
5889}
5890
5891/*
5892 * What we do here is to mark the in-core inode as clean with respect to inode
5893 * dirtiness (it may still be data-dirty).
5894 * This means that the in-core inode may be reaped by prune_icache
5895 * without having to perform any I/O.  This is a very good thing,
5896 * because *any* task may call prune_icache - even ones which
5897 * have a transaction open against a different journal.
5898 *
5899 * Is this cheating?  Not really.  Sure, we haven't written the
5900 * inode out, but prune_icache isn't a user-visible syncing function.
5901 * Whenever the user wants stuff synced (sys_sync, sys_msync, sys_fsync)
5902 * we start and wait on commits.
5903 */
5904int ext4_mark_inode_dirty(handle_t *handle, struct inode *inode)
 
5905{
5906	struct ext4_iloc iloc;
5907	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
5908	int err;
5909
5910	might_sleep();
5911	trace_ext4_mark_inode_dirty(inode, _RET_IP_);
5912	err = ext4_reserve_inode_write(handle, inode, &iloc);
5913	if (err)
5914		return err;
5915
5916	if (EXT4_I(inode)->i_extra_isize < sbi->s_want_extra_isize)
5917		ext4_try_to_expand_extra_isize(inode, sbi->s_want_extra_isize,
5918					       iloc, handle);
5919
5920	return ext4_mark_iloc_dirty(handle, inode, &iloc);
 
 
 
 
 
5921}
5922
5923/*
5924 * ext4_dirty_inode() is called from __mark_inode_dirty()
5925 *
5926 * We're really interested in the case where a file is being extended.
5927 * i_size has been changed by generic_commit_write() and we thus need
5928 * to include the updated inode in the current transaction.
5929 *
5930 * Also, dquot_alloc_block() will always dirty the inode when blocks
5931 * are allocated to the file.
5932 *
5933 * If the inode is marked synchronous, we don't honour that here - doing
5934 * so would cause a commit on atime updates, which we don't bother doing.
5935 * We handle synchronous inodes at the highest possible level.
5936 *
5937 * If only the I_DIRTY_TIME flag is set, we can skip everything.  If
5938 * I_DIRTY_TIME and I_DIRTY_SYNC is set, the only inode fields we need
5939 * to copy into the on-disk inode structure are the timestamp files.
5940 */
5941void ext4_dirty_inode(struct inode *inode, int flags)
5942{
5943	handle_t *handle;
5944
5945	if (flags == I_DIRTY_TIME)
5946		return;
5947	handle = ext4_journal_start(inode, EXT4_HT_INODE, 2);
5948	if (IS_ERR(handle))
5949		goto out;
5950
5951	ext4_mark_inode_dirty(handle, inode);
5952
5953	ext4_journal_stop(handle);
5954out:
5955	return;
5956}
5957
5958#if 0
5959/*
5960 * Bind an inode's backing buffer_head into this transaction, to prevent
5961 * it from being flushed to disk early.  Unlike
5962 * ext4_reserve_inode_write, this leaves behind no bh reference and
5963 * returns no iloc structure, so the caller needs to repeat the iloc
5964 * lookup to mark the inode dirty later.
5965 */
5966static int ext4_pin_inode(handle_t *handle, struct inode *inode)
5967{
5968	struct ext4_iloc iloc;
5969
5970	int err = 0;
5971	if (handle) {
5972		err = ext4_get_inode_loc(inode, &iloc);
5973		if (!err) {
5974			BUFFER_TRACE(iloc.bh, "get_write_access");
5975			err = jbd2_journal_get_write_access(handle, iloc.bh);
5976			if (!err)
5977				err = ext4_handle_dirty_metadata(handle,
5978								 NULL,
5979								 iloc.bh);
5980			brelse(iloc.bh);
5981		}
5982	}
5983	ext4_std_error(inode->i_sb, err);
5984	return err;
5985}
5986#endif
5987
5988int ext4_change_inode_journal_flag(struct inode *inode, int val)
5989{
5990	journal_t *journal;
5991	handle_t *handle;
5992	int err;
5993	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
5994
5995	/*
5996	 * We have to be very careful here: changing a data block's
5997	 * journaling status dynamically is dangerous.  If we write a
5998	 * data block to the journal, change the status and then delete
5999	 * that block, we risk forgetting to revoke the old log record
6000	 * from the journal and so a subsequent replay can corrupt data.
6001	 * So, first we make sure that the journal is empty and that
6002	 * nobody is changing anything.
6003	 */
6004
6005	journal = EXT4_JOURNAL(inode);
6006	if (!journal)
6007		return 0;
6008	if (is_journal_aborted(journal))
6009		return -EROFS;
6010
6011	/* Wait for all existing dio workers */
6012	inode_dio_wait(inode);
6013
6014	/*
6015	 * Before flushing the journal and switching inode's aops, we have
6016	 * to flush all dirty data the inode has. There can be outstanding
6017	 * delayed allocations, there can be unwritten extents created by
6018	 * fallocate or buffered writes in dioread_nolock mode covered by
6019	 * dirty data which can be converted only after flushing the dirty
6020	 * data (and journalled aops don't know how to handle these cases).
6021	 */
6022	if (val) {
6023		down_write(&EXT4_I(inode)->i_mmap_sem);
6024		err = filemap_write_and_wait(inode->i_mapping);
6025		if (err < 0) {
6026			up_write(&EXT4_I(inode)->i_mmap_sem);
6027			return err;
6028		}
6029	}
6030
6031	percpu_down_write(&sbi->s_journal_flag_rwsem);
6032	jbd2_journal_lock_updates(journal);
6033
6034	/*
6035	 * OK, there are no updates running now, and all cached data is
6036	 * synced to disk.  We are now in a completely consistent state
6037	 * which doesn't have anything in the journal, and we know that
6038	 * no filesystem updates are running, so it is safe to modify
6039	 * the inode's in-core data-journaling state flag now.
6040	 */
6041
6042	if (val)
6043		ext4_set_inode_flag(inode, EXT4_INODE_JOURNAL_DATA);
6044	else {
6045		err = jbd2_journal_flush(journal);
6046		if (err < 0) {
6047			jbd2_journal_unlock_updates(journal);
6048			percpu_up_write(&sbi->s_journal_flag_rwsem);
6049			return err;
6050		}
6051		ext4_clear_inode_flag(inode, EXT4_INODE_JOURNAL_DATA);
6052	}
6053	ext4_set_aops(inode);
6054
6055	jbd2_journal_unlock_updates(journal);
6056	percpu_up_write(&sbi->s_journal_flag_rwsem);
6057
6058	if (val)
6059		up_write(&EXT4_I(inode)->i_mmap_sem);
6060
6061	/* Finally we can mark the inode as dirty. */
6062
6063	handle = ext4_journal_start(inode, EXT4_HT_INODE, 1);
6064	if (IS_ERR(handle))
6065		return PTR_ERR(handle);
6066
 
 
6067	err = ext4_mark_inode_dirty(handle, inode);
6068	ext4_handle_sync(handle);
6069	ext4_journal_stop(handle);
6070	ext4_std_error(inode->i_sb, err);
6071
6072	return err;
6073}
6074
6075static int ext4_bh_unmapped(handle_t *handle, struct buffer_head *bh)
6076{
6077	return !buffer_mapped(bh);
6078}
6079
6080int ext4_page_mkwrite(struct vm_fault *vmf)
6081{
6082	struct vm_area_struct *vma = vmf->vma;
6083	struct page *page = vmf->page;
6084	loff_t size;
6085	unsigned long len;
6086	int ret;
 
6087	struct file *file = vma->vm_file;
6088	struct inode *inode = file_inode(file);
6089	struct address_space *mapping = inode->i_mapping;
6090	handle_t *handle;
6091	get_block_t *get_block;
6092	int retries = 0;
6093
 
 
 
6094	sb_start_pagefault(inode->i_sb);
6095	file_update_time(vma->vm_file);
6096
6097	down_read(&EXT4_I(inode)->i_mmap_sem);
6098
6099	ret = ext4_convert_inline_data(inode);
6100	if (ret)
6101		goto out_ret;
6102
 
 
 
 
 
 
 
 
 
6103	/* Delalloc case is easy... */
6104	if (test_opt(inode->i_sb, DELALLOC) &&
6105	    !ext4_should_journal_data(inode) &&
6106	    !ext4_nonda_switch(inode->i_sb)) {
6107		do {
6108			ret = block_page_mkwrite(vma, vmf,
6109						   ext4_da_get_block_prep);
6110		} while (ret == -ENOSPC &&
6111		       ext4_should_retry_alloc(inode->i_sb, &retries));
6112		goto out_ret;
6113	}
6114
6115	lock_page(page);
6116	size = i_size_read(inode);
6117	/* Page got truncated from under us? */
6118	if (page->mapping != mapping || page_offset(page) > size) {
6119		unlock_page(page);
6120		ret = VM_FAULT_NOPAGE;
6121		goto out;
6122	}
6123
6124	if (page->index == size >> PAGE_SHIFT)
6125		len = size & ~PAGE_MASK;
6126	else
6127		len = PAGE_SIZE;
6128	/*
6129	 * Return if we have all the buffers mapped. This avoids the need to do
6130	 * journal_start/journal_stop which can block and take a long time
 
 
 
6131	 */
6132	if (page_has_buffers(page)) {
6133		if (!ext4_walk_page_buffers(NULL, page_buffers(page),
6134					    0, len, NULL,
6135					    ext4_bh_unmapped)) {
6136			/* Wait so that we don't change page under IO */
6137			wait_for_stable_page(page);
6138			ret = VM_FAULT_LOCKED;
6139			goto out;
6140		}
6141	}
6142	unlock_page(page);
6143	/* OK, we need to fill the hole... */
6144	if (ext4_should_dioread_nolock(inode))
6145		get_block = ext4_get_block_unwritten;
6146	else
6147		get_block = ext4_get_block;
6148retry_alloc:
6149	handle = ext4_journal_start(inode, EXT4_HT_WRITE_PAGE,
6150				    ext4_writepage_trans_blocks(inode));
6151	if (IS_ERR(handle)) {
6152		ret = VM_FAULT_SIGBUS;
6153		goto out;
6154	}
6155	ret = block_page_mkwrite(vma, vmf, get_block);
6156	if (!ret && ext4_should_journal_data(inode)) {
6157		if (ext4_walk_page_buffers(handle, page_buffers(page), 0,
6158			  PAGE_SIZE, NULL, do_journal_get_write_access)) {
6159			unlock_page(page);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
6160			ret = VM_FAULT_SIGBUS;
6161			ext4_journal_stop(handle);
6162			goto out;
 
 
 
 
 
 
 
 
 
 
6163		}
6164		ext4_set_inode_state(inode, EXT4_STATE_JDATA);
6165	}
6166	ext4_journal_stop(handle);
6167	if (ret == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
6168		goto retry_alloc;
6169out_ret:
6170	ret = block_page_mkwrite_return(ret);
6171out:
6172	up_read(&EXT4_I(inode)->i_mmap_sem);
6173	sb_end_pagefault(inode->i_sb);
6174	return ret;
 
 
 
 
6175}
6176
6177int ext4_filemap_fault(struct vm_fault *vmf)
6178{
6179	struct inode *inode = file_inode(vmf->vma->vm_file);
6180	int err;
6181
6182	down_read(&EXT4_I(inode)->i_mmap_sem);
6183	err = filemap_fault(vmf);
6184	up_read(&EXT4_I(inode)->i_mmap_sem);
6185
6186	return err;
6187}