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
  51static __u32 ext4_inode_csum(struct inode *inode, struct ext4_inode *raw,
  52			      struct ext4_inode_info *ei)
  53{
  54	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
  55	__u32 csum;
  56	__u16 dummy_csum = 0;
  57	int offset = offsetof(struct ext4_inode, i_checksum_lo);
  58	unsigned int csum_size = sizeof(dummy_csum);
  59
  60	csum = ext4_chksum(sbi, ei->i_csum_seed, (__u8 *)raw, offset);
  61	csum = ext4_chksum(sbi, csum, (__u8 *)&dummy_csum, csum_size);
  62	offset += csum_size;
  63	csum = ext4_chksum(sbi, csum, (__u8 *)raw + offset,
  64			   EXT4_GOOD_OLD_INODE_SIZE - offset);
  65
  66	if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE) {
  67		offset = offsetof(struct ext4_inode, i_checksum_hi);
  68		csum = ext4_chksum(sbi, csum, (__u8 *)raw +
  69				   EXT4_GOOD_OLD_INODE_SIZE,
  70				   offset - EXT4_GOOD_OLD_INODE_SIZE);
  71		if (EXT4_FITS_IN_INODE(raw, ei, i_checksum_hi)) {
  72			csum = ext4_chksum(sbi, csum, (__u8 *)&dummy_csum,
  73					   csum_size);
  74			offset += csum_size;
  75		}
  76		csum = ext4_chksum(sbi, csum, (__u8 *)raw + offset,
  77				   EXT4_INODE_SIZE(inode->i_sb) - offset);
  78	}
  79
  80	return csum;
  81}
  82
  83static int ext4_inode_csum_verify(struct inode *inode, struct ext4_inode *raw,
  84				  struct ext4_inode_info *ei)
  85{
  86	__u32 provided, calculated;
  87
  88	if (EXT4_SB(inode->i_sb)->s_es->s_creator_os !=
  89	    cpu_to_le32(EXT4_OS_LINUX) ||
  90	    !ext4_has_metadata_csum(inode->i_sb))
  91		return 1;
  92
  93	provided = le16_to_cpu(raw->i_checksum_lo);
  94	calculated = ext4_inode_csum(inode, raw, ei);
  95	if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE &&
  96	    EXT4_FITS_IN_INODE(raw, ei, i_checksum_hi))
  97		provided |= ((__u32)le16_to_cpu(raw->i_checksum_hi)) << 16;
  98	else
  99		calculated &= 0xFFFF;
 100
 101	return provided == calculated;
 102}
 103
 104static void ext4_inode_csum_set(struct inode *inode, struct ext4_inode *raw,
 105				struct ext4_inode_info *ei)
 106{
 107	__u32 csum;
 108
 109	if (EXT4_SB(inode->i_sb)->s_es->s_creator_os !=
 110	    cpu_to_le32(EXT4_OS_LINUX) ||
 111	    !ext4_has_metadata_csum(inode->i_sb))
 112		return;
 113
 114	csum = ext4_inode_csum(inode, raw, ei);
 115	raw->i_checksum_lo = cpu_to_le16(csum & 0xFFFF);
 116	if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE &&
 117	    EXT4_FITS_IN_INODE(raw, ei, i_checksum_hi))
 118		raw->i_checksum_hi = cpu_to_le16(csum >> 16);
 119}
 120
 121static inline int ext4_begin_ordered_truncate(struct inode *inode,
 122					      loff_t new_size)
 123{
 124	trace_ext4_begin_ordered_truncate(inode, new_size);
 125	/*
 126	 * If jinode is zero, then we never opened the file for
 127	 * writing, so there's no need to call
 128	 * jbd2_journal_begin_ordered_truncate() since there's no
 129	 * outstanding writes we need to flush.
 130	 */
 131	if (!EXT4_I(inode)->jinode)
 132		return 0;
 133	return jbd2_journal_begin_ordered_truncate(EXT4_JOURNAL(inode),
 134						   EXT4_I(inode)->jinode,
 135						   new_size);
 136}
 137
 138static void ext4_invalidatepage(struct page *page, unsigned int offset,
 139				unsigned int length);
 140static int __ext4_journalled_writepage(struct page *page, unsigned int len);
 141static int ext4_bh_delay_or_unwritten(handle_t *handle, struct buffer_head *bh);
 142static int ext4_meta_trans_blocks(struct inode *inode, int lblocks,
 143				  int pextents);
 144
 145/*
 146 * Test whether an inode is a fast symlink.
 147 * A fast symlink has its symlink data stored in ext4_inode_info->i_data.
 148 */
 149int ext4_inode_is_fast_symlink(struct inode *inode)
 150{
 151	if (!(EXT4_I(inode)->i_flags & EXT4_EA_INODE_FL)) {
 152		int ea_blocks = EXT4_I(inode)->i_file_acl ?
 153				EXT4_CLUSTER_SIZE(inode->i_sb) >> 9 : 0;
 154
 155		if (ext4_has_inline_data(inode))
 156			return 0;
 157
 158		return (S_ISLNK(inode->i_mode) && inode->i_blocks - ea_blocks == 0);
 159	}
 160	return S_ISLNK(inode->i_mode) && inode->i_size &&
 161	       (inode->i_size < EXT4_N_BLOCKS * 4);
 162}
 163
 164/*
 165 * Called at the last iput() if i_nlink is zero.
 166 */
 167void ext4_evict_inode(struct inode *inode)
 168{
 169	handle_t *handle;
 170	int err;
 171	/*
 172	 * Credits for final inode cleanup and freeing:
 173	 * sb + inode (ext4_orphan_del()), block bitmap, group descriptor
 174	 * (xattr block freeing), bitmap, group descriptor (inode freeing)
 175	 */
 176	int extra_credits = 6;
 177	struct ext4_xattr_inode_array *ea_inode_array = NULL;
 
 178
 179	trace_ext4_evict_inode(inode);
 180
 
 
 181	if (inode->i_nlink) {
 182		/*
 183		 * When journalling data dirty buffers are tracked only in the
 184		 * journal. So although mm thinks everything is clean and
 185		 * ready for reaping the inode might still have some pages to
 186		 * write in the running transaction or waiting to be
 187		 * checkpointed. Thus calling jbd2_journal_invalidatepage()
 188		 * (via truncate_inode_pages()) to discard these buffers can
 189		 * cause data loss. Also even if we did not discard these
 190		 * buffers, we would have no way to find them after the inode
 191		 * is reaped and thus user could see stale data if he tries to
 192		 * read them before the transaction is checkpointed. So be
 193		 * careful and force everything to disk here... We use
 194		 * ei->i_datasync_tid to store the newest transaction
 195		 * containing inode's data.
 196		 *
 197		 * Note that directories do not have this problem because they
 198		 * don't use page cache.
 199		 */
 200		if (inode->i_ino != EXT4_JOURNAL_INO &&
 201		    ext4_should_journal_data(inode) &&
 202		    (S_ISLNK(inode->i_mode) || S_ISREG(inode->i_mode)) &&
 203		    inode->i_data.nrpages) {
 204			journal_t *journal = EXT4_SB(inode->i_sb)->s_journal;
 205			tid_t commit_tid = EXT4_I(inode)->i_datasync_tid;
 206
 207			jbd2_complete_transaction(journal, commit_tid);
 208			filemap_write_and_wait(&inode->i_data);
 209		}
 210		truncate_inode_pages_final(&inode->i_data);
 211
 212		goto no_delete;
 213	}
 214
 215	if (is_bad_inode(inode))
 216		goto no_delete;
 217	dquot_initialize(inode);
 218
 219	if (ext4_should_order_data(inode))
 220		ext4_begin_ordered_truncate(inode, 0);
 221	truncate_inode_pages_final(&inode->i_data);
 222
 223	/*
 224	 * For inodes with journalled data, transaction commit could have
 225	 * dirtied the inode. Flush worker is ignoring it because of I_FREEING
 226	 * flag but we still need to remove the inode from the writeback lists.
 
 
 227	 */
 228	if (!list_empty_careful(&inode->i_io_list)) {
 229		WARN_ON_ONCE(!ext4_should_journal_data(inode));
 230		inode_io_list_del(inode);
 231	}
 232
 233	/*
 234	 * Protect us against freezing - iput() caller didn't have to have any
 235	 * protection against it
 236	 */
 237	sb_start_intwrite(inode->i_sb);
 
 
 
 
 
 238
 239	if (!IS_NOQUOTA(inode))
 240		extra_credits += EXT4_MAXQUOTAS_DEL_BLOCKS(inode->i_sb);
 241
 242	/*
 243	 * Block bitmap, group descriptor, and inode are accounted in both
 244	 * ext4_blocks_for_truncate() and extra_credits. So subtract 3.
 245	 */
 246	handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE,
 247			 ext4_blocks_for_truncate(inode) + extra_credits - 3);
 248	if (IS_ERR(handle)) {
 249		ext4_std_error(inode->i_sb, PTR_ERR(handle));
 250		/*
 251		 * If we're going to skip the normal cleanup, we still need to
 252		 * make sure that the in-core orphan linked list is properly
 253		 * cleaned up.
 254		 */
 255		ext4_orphan_del(NULL, inode);
 256		sb_end_intwrite(inode->i_sb);
 
 257		goto no_delete;
 258	}
 259
 260	if (IS_SYNC(inode))
 261		ext4_handle_sync(handle);
 262
 263	/*
 264	 * Set inode->i_size to 0 before calling ext4_truncate(). We need
 265	 * special handling of symlinks here because i_size is used to
 266	 * determine whether ext4_inode_info->i_data contains symlink data or
 267	 * block mappings. Setting i_size to 0 will remove its fast symlink
 268	 * status. Erase i_data so that it becomes a valid empty block map.
 269	 */
 270	if (ext4_inode_is_fast_symlink(inode))
 271		memset(EXT4_I(inode)->i_data, 0, sizeof(EXT4_I(inode)->i_data));
 272	inode->i_size = 0;
 273	err = ext4_mark_inode_dirty(handle, inode);
 274	if (err) {
 275		ext4_warning(inode->i_sb,
 276			     "couldn't mark inode dirty (err %d)", err);
 277		goto stop_handle;
 278	}
 279	if (inode->i_blocks) {
 280		err = ext4_truncate(inode);
 281		if (err) {
 282			ext4_error_err(inode->i_sb, -err,
 283				       "couldn't truncate inode %lu (err %d)",
 284				       inode->i_ino, err);
 285			goto stop_handle;
 286		}
 287	}
 288
 289	/* Remove xattr references. */
 290	err = ext4_xattr_delete_inode(handle, inode, &ea_inode_array,
 291				      extra_credits);
 292	if (err) {
 293		ext4_warning(inode->i_sb, "xattr delete (err %d)", err);
 294stop_handle:
 295		ext4_journal_stop(handle);
 296		ext4_orphan_del(NULL, inode);
 297		sb_end_intwrite(inode->i_sb);
 
 298		ext4_xattr_inode_array_free(ea_inode_array);
 299		goto no_delete;
 300	}
 301
 302	/*
 303	 * Kill off the orphan record which ext4_truncate created.
 304	 * AKPM: I think this can be inside the above `if'.
 305	 * Note that ext4_orphan_del() has to be able to cope with the
 306	 * deletion of a non-existent orphan - this is because we don't
 307	 * know if ext4_truncate() actually created an orphan record.
 308	 * (Well, we could do this if we need to, but heck - it works)
 309	 */
 310	ext4_orphan_del(handle, inode);
 311	EXT4_I(inode)->i_dtime	= (__u32)ktime_get_real_seconds();
 312
 313	/*
 314	 * One subtle ordering requirement: if anything has gone wrong
 315	 * (transaction abort, IO errors, whatever), then we can still
 316	 * do these next steps (the fs will already have been marked as
 317	 * having errors), but we can't free the inode if the mark_dirty
 318	 * fails.
 319	 */
 320	if (ext4_mark_inode_dirty(handle, inode))
 321		/* If that failed, just do the required in-core inode clear. */
 322		ext4_clear_inode(inode);
 323	else
 324		ext4_free_inode(handle, inode);
 325	ext4_journal_stop(handle);
 326	sb_end_intwrite(inode->i_sb);
 
 327	ext4_xattr_inode_array_free(ea_inode_array);
 328	return;
 329no_delete:
 
 
 
 
 
 
 
 
 330	ext4_clear_inode(inode);	/* We must guarantee clearing of inode... */
 331}
 332
 333#ifdef CONFIG_QUOTA
 334qsize_t *ext4_get_reserved_space(struct inode *inode)
 335{
 336	return &EXT4_I(inode)->i_reserved_quota;
 337}
 338#endif
 339
 340/*
 341 * Called with i_data_sem down, which is important since we can call
 342 * ext4_discard_preallocations() from here.
 343 */
 344void ext4_da_update_reserve_space(struct inode *inode,
 345					int used, int quota_claim)
 346{
 347	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
 348	struct ext4_inode_info *ei = EXT4_I(inode);
 349
 350	spin_lock(&ei->i_block_reservation_lock);
 351	trace_ext4_da_update_reserve_space(inode, used, quota_claim);
 352	if (unlikely(used > ei->i_reserved_data_blocks)) {
 353		ext4_warning(inode->i_sb, "%s: ino %lu, used %d "
 354			 "with only %d reserved data blocks",
 355			 __func__, inode->i_ino, used,
 356			 ei->i_reserved_data_blocks);
 357		WARN_ON(1);
 358		used = ei->i_reserved_data_blocks;
 359	}
 360
 361	/* Update per-inode reservations */
 362	ei->i_reserved_data_blocks -= used;
 363	percpu_counter_sub(&sbi->s_dirtyclusters_counter, used);
 364
 365	spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
 366
 367	/* Update quota subsystem for data blocks */
 368	if (quota_claim)
 369		dquot_claim_block(inode, EXT4_C2B(sbi, used));
 370	else {
 371		/*
 372		 * We did fallocate with an offset that is already delayed
 373		 * allocated. So on delayed allocated writeback we should
 374		 * not re-claim the quota for fallocated blocks.
 375		 */
 376		dquot_release_reservation_block(inode, EXT4_C2B(sbi, used));
 377	}
 378
 379	/*
 380	 * If we have done all the pending block allocations and if
 381	 * there aren't any writers on the inode, we can discard the
 382	 * inode's preallocations.
 383	 */
 384	if ((ei->i_reserved_data_blocks == 0) &&
 385	    !inode_is_open_for_write(inode))
 386		ext4_discard_preallocations(inode, 0);
 387}
 388
 389static int __check_block_validity(struct inode *inode, const char *func,
 390				unsigned int line,
 391				struct ext4_map_blocks *map)
 392{
 393	if (ext4_has_feature_journal(inode->i_sb) &&
 394	    (inode->i_ino ==
 395	     le32_to_cpu(EXT4_SB(inode->i_sb)->s_es->s_journal_inum)))
 396		return 0;
 397	if (!ext4_inode_block_valid(inode, map->m_pblk, map->m_len)) {
 398		ext4_error_inode(inode, func, line, map->m_pblk,
 399				 "lblock %lu mapped to illegal pblock %llu "
 400				 "(length %d)", (unsigned long) map->m_lblk,
 401				 map->m_pblk, map->m_len);
 402		return -EFSCORRUPTED;
 403	}
 404	return 0;
 405}
 406
 407int ext4_issue_zeroout(struct inode *inode, ext4_lblk_t lblk, ext4_fsblk_t pblk,
 408		       ext4_lblk_t len)
 409{
 410	int ret;
 411
 412	if (IS_ENCRYPTED(inode) && S_ISREG(inode->i_mode))
 413		return fscrypt_zeroout_range(inode, lblk, pblk, len);
 414
 415	ret = sb_issue_zeroout(inode->i_sb, pblk, len, GFP_NOFS);
 416	if (ret > 0)
 417		ret = 0;
 418
 419	return ret;
 420}
 421
 422#define check_block_validity(inode, map)	\
 423	__check_block_validity((inode), __func__, __LINE__, (map))
 424
 425#ifdef ES_AGGRESSIVE_TEST
 426static void ext4_map_blocks_es_recheck(handle_t *handle,
 427				       struct inode *inode,
 428				       struct ext4_map_blocks *es_map,
 429				       struct ext4_map_blocks *map,
 430				       int flags)
 431{
 432	int retval;
 433
 434	map->m_flags = 0;
 435	/*
 436	 * There is a race window that the result is not the same.
 437	 * e.g. xfstests #223 when dioread_nolock enables.  The reason
 438	 * is that we lookup a block mapping in extent status tree with
 439	 * out taking i_data_sem.  So at the time the unwritten extent
 440	 * could be converted.
 441	 */
 442	down_read(&EXT4_I(inode)->i_data_sem);
 443	if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) {
 444		retval = ext4_ext_map_blocks(handle, inode, map, 0);
 445	} else {
 446		retval = ext4_ind_map_blocks(handle, inode, map, 0);
 447	}
 448	up_read((&EXT4_I(inode)->i_data_sem));
 449
 450	/*
 451	 * We don't check m_len because extent will be collpased in status
 452	 * tree.  So the m_len might not equal.
 453	 */
 454	if (es_map->m_lblk != map->m_lblk ||
 455	    es_map->m_flags != map->m_flags ||
 456	    es_map->m_pblk != map->m_pblk) {
 457		printk("ES cache assertion failed for inode: %lu "
 458		       "es_cached ex [%d/%d/%llu/%x] != "
 459		       "found ex [%d/%d/%llu/%x] retval %d flags %x\n",
 460		       inode->i_ino, es_map->m_lblk, es_map->m_len,
 461		       es_map->m_pblk, es_map->m_flags, map->m_lblk,
 462		       map->m_len, map->m_pblk, map->m_flags,
 463		       retval, flags);
 464	}
 465}
 466#endif /* ES_AGGRESSIVE_TEST */
 467
 468/*
 469 * The ext4_map_blocks() function tries to look up the requested blocks,
 470 * and returns if the blocks are already mapped.
 471 *
 472 * Otherwise it takes the write lock of the i_data_sem and allocate blocks
 473 * and store the allocated blocks in the result buffer head and mark it
 474 * mapped.
 475 *
 476 * If file type is extents based, it will call ext4_ext_map_blocks(),
 477 * Otherwise, call with ext4_ind_map_blocks() to handle indirect mapping
 478 * based files
 479 *
 480 * On success, it returns the number of blocks being mapped or allocated.  if
 481 * create==0 and the blocks are pre-allocated and unwritten, the resulting @map
 482 * is marked as unwritten. If the create == 1, it will mark @map as mapped.
 483 *
 484 * It returns 0 if plain look up failed (blocks have not been allocated), in
 485 * that case, @map is returned as unmapped but we still do fill map->m_len to
 486 * indicate the length of a hole starting at map->m_lblk.
 487 *
 488 * It returns the error in case of allocation failure.
 489 */
 490int ext4_map_blocks(handle_t *handle, struct inode *inode,
 491		    struct ext4_map_blocks *map, int flags)
 492{
 493	struct extent_status es;
 494	int retval;
 495	int ret = 0;
 496#ifdef ES_AGGRESSIVE_TEST
 497	struct ext4_map_blocks orig_map;
 498
 499	memcpy(&orig_map, map, sizeof(*map));
 500#endif
 501
 502	map->m_flags = 0;
 503	ext_debug(inode, "flag 0x%x, max_blocks %u, logical block %lu\n",
 504		  flags, map->m_len, (unsigned long) map->m_lblk);
 505
 506	/*
 507	 * ext4_map_blocks returns an int, and m_len is an unsigned int
 508	 */
 509	if (unlikely(map->m_len > INT_MAX))
 510		map->m_len = INT_MAX;
 511
 512	/* We can handle the block number less than EXT_MAX_BLOCKS */
 513	if (unlikely(map->m_lblk >= EXT_MAX_BLOCKS))
 514		return -EFSCORRUPTED;
 515
 516	/* Lookup extent status tree firstly */
 517	if (ext4_es_lookup_extent(inode, map->m_lblk, NULL, &es)) {
 
 518		if (ext4_es_is_written(&es) || ext4_es_is_unwritten(&es)) {
 519			map->m_pblk = ext4_es_pblock(&es) +
 520					map->m_lblk - es.es_lblk;
 521			map->m_flags |= ext4_es_is_written(&es) ?
 522					EXT4_MAP_MAPPED : EXT4_MAP_UNWRITTEN;
 523			retval = es.es_len - (map->m_lblk - es.es_lblk);
 524			if (retval > map->m_len)
 525				retval = map->m_len;
 526			map->m_len = retval;
 527		} else if (ext4_es_is_delayed(&es) || ext4_es_is_hole(&es)) {
 528			map->m_pblk = 0;
 529			retval = es.es_len - (map->m_lblk - es.es_lblk);
 530			if (retval > map->m_len)
 531				retval = map->m_len;
 532			map->m_len = retval;
 533			retval = 0;
 534		} else {
 535			BUG();
 536		}
 
 
 
 537#ifdef ES_AGGRESSIVE_TEST
 538		ext4_map_blocks_es_recheck(handle, inode, map,
 539					   &orig_map, flags);
 540#endif
 541		goto found;
 542	}
 
 
 
 
 
 
 543
 544	/*
 545	 * Try to see if we can get the block without requesting a new
 546	 * file system block.
 547	 */
 548	down_read(&EXT4_I(inode)->i_data_sem);
 549	if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) {
 550		retval = ext4_ext_map_blocks(handle, inode, map, 0);
 551	} else {
 552		retval = ext4_ind_map_blocks(handle, inode, map, 0);
 553	}
 554	if (retval > 0) {
 555		unsigned int status;
 556
 557		if (unlikely(retval != map->m_len)) {
 558			ext4_warning(inode->i_sb,
 559				     "ES len assertion failed for inode "
 560				     "%lu: retval %d != map->m_len %d",
 561				     inode->i_ino, retval, map->m_len);
 562			WARN_ON(1);
 563		}
 564
 565		status = map->m_flags & EXT4_MAP_UNWRITTEN ?
 566				EXTENT_STATUS_UNWRITTEN : EXTENT_STATUS_WRITTEN;
 567		if (!(flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE) &&
 568		    !(status & EXTENT_STATUS_WRITTEN) &&
 569		    ext4_es_scan_range(inode, &ext4_es_is_delayed, map->m_lblk,
 570				       map->m_lblk + map->m_len - 1))
 571			status |= EXTENT_STATUS_DELAYED;
 572		ret = ext4_es_insert_extent(inode, map->m_lblk,
 573					    map->m_len, map->m_pblk, status);
 574		if (ret < 0)
 575			retval = ret;
 576	}
 577	up_read((&EXT4_I(inode)->i_data_sem));
 578
 579found:
 580	if (retval > 0 && map->m_flags & EXT4_MAP_MAPPED) {
 581		ret = check_block_validity(inode, map);
 582		if (ret != 0)
 583			return ret;
 584	}
 585
 586	/* If it is only a block(s) look up */
 587	if ((flags & EXT4_GET_BLOCKS_CREATE) == 0)
 588		return retval;
 589
 590	/*
 591	 * Returns if the blocks have already allocated
 592	 *
 593	 * Note that if blocks have been preallocated
 594	 * ext4_ext_get_block() returns the create = 0
 595	 * with buffer head unmapped.
 596	 */
 597	if (retval > 0 && map->m_flags & EXT4_MAP_MAPPED)
 598		/*
 599		 * If we need to convert extent to unwritten
 600		 * we continue and do the actual work in
 601		 * ext4_ext_map_blocks()
 602		 */
 603		if (!(flags & EXT4_GET_BLOCKS_CONVERT_UNWRITTEN))
 604			return retval;
 605
 606	/*
 607	 * Here we clear m_flags because after allocating an new extent,
 608	 * it will be set again.
 609	 */
 610	map->m_flags &= ~EXT4_MAP_FLAGS;
 611
 612	/*
 613	 * New blocks allocate and/or writing to unwritten extent
 614	 * will possibly result in updating i_data, so we take
 615	 * the write lock of i_data_sem, and call get_block()
 616	 * with create == 1 flag.
 617	 */
 618	down_write(&EXT4_I(inode)->i_data_sem);
 619
 620	/*
 621	 * We need to check for EXT4 here because migrate
 622	 * could have changed the inode type in between
 623	 */
 624	if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) {
 625		retval = ext4_ext_map_blocks(handle, inode, map, flags);
 626	} else {
 627		retval = ext4_ind_map_blocks(handle, inode, map, flags);
 628
 629		if (retval > 0 && map->m_flags & EXT4_MAP_NEW) {
 630			/*
 631			 * We allocated new blocks which will result in
 632			 * i_data's format changing.  Force the migrate
 633			 * to fail by clearing migrate flags
 634			 */
 635			ext4_clear_inode_state(inode, EXT4_STATE_EXT_MIGRATE);
 636		}
 637
 638		/*
 639		 * Update reserved blocks/metadata blocks after successful
 640		 * block allocation which had been deferred till now. We don't
 641		 * support fallocate for non extent files. So we can update
 642		 * reserve space here.
 643		 */
 644		if ((retval > 0) &&
 645			(flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE))
 646			ext4_da_update_reserve_space(inode, retval, 1);
 647	}
 648
 649	if (retval > 0) {
 650		unsigned int status;
 651
 652		if (unlikely(retval != map->m_len)) {
 653			ext4_warning(inode->i_sb,
 654				     "ES len assertion failed for inode "
 655				     "%lu: retval %d != map->m_len %d",
 656				     inode->i_ino, retval, map->m_len);
 657			WARN_ON(1);
 658		}
 659
 660		/*
 661		 * We have to zeroout blocks before inserting them into extent
 662		 * status tree. Otherwise someone could look them up there and
 663		 * use them before they are really zeroed. We also have to
 664		 * unmap metadata before zeroing as otherwise writeback can
 665		 * overwrite zeros with stale data from block device.
 666		 */
 667		if (flags & EXT4_GET_BLOCKS_ZERO &&
 668		    map->m_flags & EXT4_MAP_MAPPED &&
 669		    map->m_flags & EXT4_MAP_NEW) {
 670			ret = ext4_issue_zeroout(inode, map->m_lblk,
 671						 map->m_pblk, map->m_len);
 672			if (ret) {
 673				retval = ret;
 674				goto out_sem;
 675			}
 676		}
 677
 678		/*
 679		 * If the extent has been zeroed out, we don't need to update
 680		 * extent status tree.
 681		 */
 682		if ((flags & EXT4_GET_BLOCKS_PRE_IO) &&
 683		    ext4_es_lookup_extent(inode, map->m_lblk, NULL, &es)) {
 684			if (ext4_es_is_written(&es))
 685				goto out_sem;
 686		}
 687		status = map->m_flags & EXT4_MAP_UNWRITTEN ?
 688				EXTENT_STATUS_UNWRITTEN : EXTENT_STATUS_WRITTEN;
 689		if (!(flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE) &&
 690		    !(status & EXTENT_STATUS_WRITTEN) &&
 691		    ext4_es_scan_range(inode, &ext4_es_is_delayed, map->m_lblk,
 692				       map->m_lblk + map->m_len - 1))
 693			status |= EXTENT_STATUS_DELAYED;
 694		ret = ext4_es_insert_extent(inode, map->m_lblk, map->m_len,
 695					    map->m_pblk, status);
 696		if (ret < 0) {
 697			retval = ret;
 698			goto out_sem;
 699		}
 700	}
 701
 702out_sem:
 703	up_write((&EXT4_I(inode)->i_data_sem));
 704	if (retval > 0 && map->m_flags & EXT4_MAP_MAPPED) {
 705		ret = check_block_validity(inode, map);
 706		if (ret != 0)
 707			return ret;
 708
 709		/*
 710		 * Inodes with freshly allocated blocks where contents will be
 711		 * visible after transaction commit must be on transaction's
 712		 * ordered data list.
 713		 */
 714		if (map->m_flags & EXT4_MAP_NEW &&
 715		    !(map->m_flags & EXT4_MAP_UNWRITTEN) &&
 716		    !(flags & EXT4_GET_BLOCKS_ZERO) &&
 717		    !ext4_is_quota_file(inode) &&
 718		    ext4_should_order_data(inode)) {
 719			loff_t start_byte =
 720				(loff_t)map->m_lblk << inode->i_blkbits;
 721			loff_t length = (loff_t)map->m_len << inode->i_blkbits;
 722
 723			if (flags & EXT4_GET_BLOCKS_IO_SUBMIT)
 724				ret = ext4_jbd2_inode_add_wait(handle, inode,
 725						start_byte, length);
 726			else
 727				ret = ext4_jbd2_inode_add_write(handle, inode,
 728						start_byte, length);
 729			if (ret)
 730				return ret;
 731		}
 732	}
 733
 
 
 
 734	if (retval < 0)
 735		ext_debug(inode, "failed with err %d\n", retval);
 736	return retval;
 737}
 738
 739/*
 740 * Update EXT4_MAP_FLAGS in bh->b_state. For buffer heads attached to pages
 741 * we have to be careful as someone else may be manipulating b_state as well.
 742 */
 743static void ext4_update_bh_state(struct buffer_head *bh, unsigned long flags)
 744{
 745	unsigned long old_state;
 746	unsigned long new_state;
 747
 748	flags &= EXT4_MAP_FLAGS;
 749
 750	/* Dummy buffer_head? Set non-atomically. */
 751	if (!bh->b_page) {
 752		bh->b_state = (bh->b_state & ~EXT4_MAP_FLAGS) | flags;
 753		return;
 754	}
 755	/*
 756	 * Someone else may be modifying b_state. Be careful! This is ugly but
 757	 * once we get rid of using bh as a container for mapping information
 758	 * to pass to / from get_block functions, this can go away.
 759	 */
 760	do {
 761		old_state = READ_ONCE(bh->b_state);
 762		new_state = (old_state & ~EXT4_MAP_FLAGS) | flags;
 763	} while (unlikely(
 764		 cmpxchg(&bh->b_state, old_state, new_state) != old_state));
 765}
 766
 767static int _ext4_get_block(struct inode *inode, sector_t iblock,
 768			   struct buffer_head *bh, int flags)
 769{
 770	struct ext4_map_blocks map;
 771	int ret = 0;
 772
 773	if (ext4_has_inline_data(inode))
 774		return -ERANGE;
 775
 776	map.m_lblk = iblock;
 777	map.m_len = bh->b_size >> inode->i_blkbits;
 778
 779	ret = ext4_map_blocks(ext4_journal_current_handle(), inode, &map,
 780			      flags);
 781	if (ret > 0) {
 782		map_bh(bh, inode->i_sb, map.m_pblk);
 783		ext4_update_bh_state(bh, map.m_flags);
 784		bh->b_size = inode->i_sb->s_blocksize * map.m_len;
 785		ret = 0;
 786	} else if (ret == 0) {
 787		/* hole case, need to fill in bh->b_size */
 788		bh->b_size = inode->i_sb->s_blocksize * map.m_len;
 789	}
 790	return ret;
 791}
 792
 793int ext4_get_block(struct inode *inode, sector_t iblock,
 794		   struct buffer_head *bh, int create)
 795{
 796	return _ext4_get_block(inode, iblock, bh,
 797			       create ? EXT4_GET_BLOCKS_CREATE : 0);
 798}
 799
 800/*
 801 * Get block function used when preparing for buffered write if we require
 802 * creating an unwritten extent if blocks haven't been allocated.  The extent
 803 * will be converted to written after the IO is complete.
 804 */
 805int ext4_get_block_unwritten(struct inode *inode, sector_t iblock,
 806			     struct buffer_head *bh_result, int create)
 807{
 808	ext4_debug("ext4_get_block_unwritten: inode %lu, create flag %d\n",
 809		   inode->i_ino, create);
 810	return _ext4_get_block(inode, iblock, bh_result,
 811			       EXT4_GET_BLOCKS_IO_CREATE_EXT);
 812}
 813
 814/* Maximum number of blocks we map for direct IO at once. */
 815#define DIO_MAX_BLOCKS 4096
 816
 817/*
 818 * `handle' can be NULL if create is zero
 819 */
 820struct buffer_head *ext4_getblk(handle_t *handle, struct inode *inode,
 821				ext4_lblk_t block, int map_flags)
 822{
 823	struct ext4_map_blocks map;
 824	struct buffer_head *bh;
 825	int create = map_flags & EXT4_GET_BLOCKS_CREATE;
 
 826	int err;
 827
 828	J_ASSERT(handle != NULL || create == 0);
 
 
 829
 830	map.m_lblk = block;
 831	map.m_len = 1;
 832	err = ext4_map_blocks(handle, inode, &map, map_flags);
 833
 834	if (err == 0)
 835		return create ? ERR_PTR(-ENOSPC) : NULL;
 836	if (err < 0)
 837		return ERR_PTR(err);
 838
 
 
 
 839	bh = sb_getblk(inode->i_sb, map.m_pblk);
 840	if (unlikely(!bh))
 841		return ERR_PTR(-ENOMEM);
 842	if (map.m_flags & EXT4_MAP_NEW) {
 843		J_ASSERT(create != 0);
 844		J_ASSERT(handle != NULL);
 
 845
 846		/*
 847		 * Now that we do not always journal data, we should
 848		 * keep in mind whether this should always journal the
 849		 * new buffer as metadata.  For now, regular file
 850		 * writes use ext4_get_block instead, so it's not a
 851		 * problem.
 852		 */
 853		lock_buffer(bh);
 854		BUFFER_TRACE(bh, "call get_create_access");
 855		err = ext4_journal_get_create_access(handle, bh);
 
 856		if (unlikely(err)) {
 857			unlock_buffer(bh);
 858			goto errout;
 859		}
 860		if (!buffer_uptodate(bh)) {
 861			memset(bh->b_data, 0, inode->i_sb->s_blocksize);
 862			set_buffer_uptodate(bh);
 863		}
 864		unlock_buffer(bh);
 865		BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
 866		err = ext4_handle_dirty_metadata(handle, inode, bh);
 867		if (unlikely(err))
 868			goto errout;
 869	} else
 870		BUFFER_TRACE(bh, "not a new buffer");
 871	return bh;
 872errout:
 873	brelse(bh);
 874	return ERR_PTR(err);
 875}
 876
 877struct buffer_head *ext4_bread(handle_t *handle, struct inode *inode,
 878			       ext4_lblk_t block, int map_flags)
 879{
 880	struct buffer_head *bh;
 
 881
 882	bh = ext4_getblk(handle, inode, block, map_flags);
 883	if (IS_ERR(bh))
 884		return bh;
 885	if (!bh || ext4_buffer_uptodate(bh))
 886		return bh;
 887	ll_rw_block(REQ_OP_READ, REQ_META | REQ_PRIO, 1, &bh);
 888	wait_on_buffer(bh);
 889	if (buffer_uptodate(bh))
 890		return bh;
 891	put_bh(bh);
 892	return ERR_PTR(-EIO);
 
 893}
 894
 895/* Read a contiguous batch of blocks. */
 896int ext4_bread_batch(struct inode *inode, ext4_lblk_t block, int bh_count,
 897		     bool wait, struct buffer_head **bhs)
 898{
 899	int i, err;
 900
 901	for (i = 0; i < bh_count; i++) {
 902		bhs[i] = ext4_getblk(NULL, inode, block + i, 0 /* map_flags */);
 903		if (IS_ERR(bhs[i])) {
 904			err = PTR_ERR(bhs[i]);
 905			bh_count = i;
 906			goto out_brelse;
 907		}
 908	}
 909
 910	for (i = 0; i < bh_count; i++)
 911		/* Note that NULL bhs[i] is valid because of holes. */
 912		if (bhs[i] && !ext4_buffer_uptodate(bhs[i]))
 913			ll_rw_block(REQ_OP_READ, REQ_META | REQ_PRIO, 1,
 914				    &bhs[i]);
 915
 916	if (!wait)
 917		return 0;
 918
 919	for (i = 0; i < bh_count; i++)
 920		if (bhs[i])
 921			wait_on_buffer(bhs[i]);
 922
 923	for (i = 0; i < bh_count; i++) {
 924		if (bhs[i] && !buffer_uptodate(bhs[i])) {
 925			err = -EIO;
 926			goto out_brelse;
 927		}
 928	}
 929	return 0;
 930
 931out_brelse:
 932	for (i = 0; i < bh_count; i++) {
 933		brelse(bhs[i]);
 934		bhs[i] = NULL;
 935	}
 936	return err;
 937}
 938
 939int ext4_walk_page_buffers(handle_t *handle,
 940			   struct buffer_head *head,
 941			   unsigned from,
 942			   unsigned to,
 943			   int *partial,
 944			   int (*fn)(handle_t *handle,
 945				     struct buffer_head *bh))
 946{
 947	struct buffer_head *bh;
 948	unsigned block_start, block_end;
 949	unsigned blocksize = head->b_size;
 950	int err, ret = 0;
 951	struct buffer_head *next;
 952
 953	for (bh = head, block_start = 0;
 954	     ret == 0 && (bh != head || !block_start);
 955	     block_start = block_end, bh = next) {
 956		next = bh->b_this_page;
 957		block_end = block_start + blocksize;
 958		if (block_end <= from || block_start >= to) {
 959			if (partial && !buffer_uptodate(bh))
 960				*partial = 1;
 961			continue;
 962		}
 963		err = (*fn)(handle, bh);
 964		if (!ret)
 965			ret = err;
 966	}
 967	return ret;
 968}
 969
 970/*
 971 * To preserve ordering, it is essential that the hole instantiation and
 972 * the data write be encapsulated in a single transaction.  We cannot
 973 * close off a transaction and start a new one between the ext4_get_block()
 974 * and the commit_write().  So doing the jbd2_journal_start at the start of
 975 * prepare_write() is the right place.
 976 *
 977 * Also, this function can nest inside ext4_writepage().  In that case, we
 978 * *know* that ext4_writepage() has generated enough buffer credits to do the
 979 * whole page.  So we won't block on the journal in that case, which is good,
 980 * because the caller may be PF_MEMALLOC.
 981 *
 982 * By accident, ext4 can be reentered when a transaction is open via
 983 * quota file writes.  If we were to commit the transaction while thus
 984 * reentered, there can be a deadlock - we would be holding a quota
 985 * lock, and the commit would never complete if another thread had a
 986 * transaction open and was blocking on the quota lock - a ranking
 987 * violation.
 988 *
 989 * So what we do is to rely on the fact that jbd2_journal_stop/journal_start
 990 * will _not_ run commit under these circumstances because handle->h_ref
 991 * is elevated.  We'll still have enough credits for the tiny quotafile
 992 * write.
 993 */
 994int do_journal_get_write_access(handle_t *handle,
 995				struct buffer_head *bh)
 996{
 997	int dirty = buffer_dirty(bh);
 998	int ret;
 999
1000	if (!buffer_mapped(bh) || buffer_freed(bh))
1001		return 0;
1002	/*
1003	 * __block_write_begin() could have dirtied some buffers. Clean
1004	 * the dirty bit as jbd2_journal_get_write_access() could complain
1005	 * otherwise about fs integrity issues. Setting of the dirty bit
1006	 * by __block_write_begin() isn't a real problem here as we clear
1007	 * the bit before releasing a page lock and thus writeback cannot
1008	 * ever write the buffer.
1009	 */
1010	if (dirty)
1011		clear_buffer_dirty(bh);
1012	BUFFER_TRACE(bh, "get write access");
1013	ret = ext4_journal_get_write_access(handle, bh);
 
1014	if (!ret && dirty)
1015		ret = ext4_handle_dirty_metadata(handle, NULL, bh);
1016	return ret;
1017}
1018
1019#ifdef CONFIG_FS_ENCRYPTION
1020static int ext4_block_write_begin(struct page *page, loff_t pos, unsigned len,
1021				  get_block_t *get_block)
1022{
1023	unsigned from = pos & (PAGE_SIZE - 1);
1024	unsigned to = from + len;
1025	struct inode *inode = page->mapping->host;
1026	unsigned block_start, block_end;
1027	sector_t block;
1028	int err = 0;
1029	unsigned blocksize = inode->i_sb->s_blocksize;
1030	unsigned bbits;
1031	struct buffer_head *bh, *head, *wait[2];
1032	int nr_wait = 0;
1033	int i;
1034
1035	BUG_ON(!PageLocked(page));
1036	BUG_ON(from > PAGE_SIZE);
1037	BUG_ON(to > PAGE_SIZE);
1038	BUG_ON(from > to);
1039
1040	if (!page_has_buffers(page))
1041		create_empty_buffers(page, blocksize, 0);
1042	head = page_buffers(page);
1043	bbits = ilog2(blocksize);
1044	block = (sector_t)page->index << (PAGE_SHIFT - bbits);
1045
1046	for (bh = head, block_start = 0; bh != head || !block_start;
1047	    block++, block_start = block_end, bh = bh->b_this_page) {
1048		block_end = block_start + blocksize;
1049		if (block_end <= from || block_start >= to) {
1050			if (PageUptodate(page)) {
1051				if (!buffer_uptodate(bh))
1052					set_buffer_uptodate(bh);
1053			}
1054			continue;
1055		}
1056		if (buffer_new(bh))
1057			clear_buffer_new(bh);
1058		if (!buffer_mapped(bh)) {
1059			WARN_ON(bh->b_size != blocksize);
1060			err = get_block(inode, block, bh, 1);
1061			if (err)
1062				break;
1063			if (buffer_new(bh)) {
1064				if (PageUptodate(page)) {
1065					clear_buffer_new(bh);
1066					set_buffer_uptodate(bh);
1067					mark_buffer_dirty(bh);
1068					continue;
1069				}
1070				if (block_end > to || block_start < from)
1071					zero_user_segments(page, to, block_end,
1072							   block_start, from);
1073				continue;
1074			}
1075		}
1076		if (PageUptodate(page)) {
1077			if (!buffer_uptodate(bh))
1078				set_buffer_uptodate(bh);
1079			continue;
1080		}
1081		if (!buffer_uptodate(bh) && !buffer_delay(bh) &&
1082		    !buffer_unwritten(bh) &&
1083		    (block_start < from || block_end > to)) {
1084			ll_rw_block(REQ_OP_READ, 0, 1, &bh);
1085			wait[nr_wait++] = bh;
1086		}
1087	}
1088	/*
1089	 * If we issued read requests, let them complete.
1090	 */
1091	for (i = 0; i < nr_wait; i++) {
1092		wait_on_buffer(wait[i]);
1093		if (!buffer_uptodate(wait[i]))
1094			err = -EIO;
1095	}
1096	if (unlikely(err)) {
1097		page_zero_new_buffers(page, from, to);
1098	} else if (fscrypt_inode_uses_fs_layer_crypto(inode)) {
1099		for (i = 0; i < nr_wait; i++) {
1100			int err2;
1101
1102			err2 = fscrypt_decrypt_pagecache_blocks(page, blocksize,
1103								bh_offset(wait[i]));
1104			if (err2) {
1105				clear_buffer_uptodate(wait[i]);
1106				err = err2;
1107			}
1108		}
1109	}
1110
1111	return err;
1112}
1113#endif
1114
1115static int ext4_write_begin(struct file *file, struct address_space *mapping,
1116			    loff_t pos, unsigned len, unsigned flags,
1117			    struct page **pagep, void **fsdata)
1118{
1119	struct inode *inode = mapping->host;
1120	int ret, needed_blocks;
1121	handle_t *handle;
1122	int retries = 0;
1123	struct page *page;
1124	pgoff_t index;
1125	unsigned from, to;
1126
1127	if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb))))
1128		return -EIO;
1129
1130	trace_ext4_write_begin(inode, pos, len, flags);
1131	/*
1132	 * Reserve one block more for addition to orphan list in case
1133	 * we allocate blocks but write fails for some reason
1134	 */
1135	needed_blocks = ext4_writepage_trans_blocks(inode) + 1;
1136	index = pos >> PAGE_SHIFT;
1137	from = pos & (PAGE_SIZE - 1);
1138	to = from + len;
1139
1140	if (ext4_test_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA)) {
1141		ret = ext4_try_to_write_inline_data(mapping, inode, pos, len,
1142						    flags, pagep);
1143		if (ret < 0)
1144			return ret;
1145		if (ret == 1)
1146			return 0;
1147	}
1148
1149	/*
1150	 * grab_cache_page_write_begin() can take a long time if the
1151	 * system is thrashing due to memory pressure, or if the page
1152	 * is being written back.  So grab it first before we start
1153	 * the transaction handle.  This also allows us to allocate
1154	 * the page (if needed) without using GFP_NOFS.
1155	 */
1156retry_grab:
1157	page = grab_cache_page_write_begin(mapping, index, flags);
1158	if (!page)
1159		return -ENOMEM;
 
 
 
 
 
 
 
1160	unlock_page(page);
1161
1162retry_journal:
1163	handle = ext4_journal_start(inode, EXT4_HT_WRITE_PAGE, needed_blocks);
1164	if (IS_ERR(handle)) {
1165		put_page(page);
1166		return PTR_ERR(handle);
1167	}
1168
1169	lock_page(page);
1170	if (page->mapping != mapping) {
1171		/* The page got truncated from under us */
1172		unlock_page(page);
1173		put_page(page);
1174		ext4_journal_stop(handle);
1175		goto retry_grab;
1176	}
1177	/* In case writeback began while the page was unlocked */
1178	wait_for_stable_page(page);
1179
1180#ifdef CONFIG_FS_ENCRYPTION
1181	if (ext4_should_dioread_nolock(inode))
1182		ret = ext4_block_write_begin(page, pos, len,
1183					     ext4_get_block_unwritten);
1184	else
1185		ret = ext4_block_write_begin(page, pos, len,
1186					     ext4_get_block);
1187#else
1188	if (ext4_should_dioread_nolock(inode))
1189		ret = __block_write_begin(page, pos, len,
1190					  ext4_get_block_unwritten);
1191	else
1192		ret = __block_write_begin(page, pos, len, ext4_get_block);
1193#endif
1194	if (!ret && ext4_should_journal_data(inode)) {
1195		ret = ext4_walk_page_buffers(handle, page_buffers(page),
1196					     from, to, NULL,
1197					     do_journal_get_write_access);
1198	}
1199
1200	if (ret) {
1201		bool extended = (pos + len > inode->i_size) &&
1202				!ext4_verity_in_progress(inode);
1203
1204		unlock_page(page);
1205		/*
1206		 * __block_write_begin may have instantiated a few blocks
1207		 * outside i_size.  Trim these off again. Don't need
1208		 * i_size_read because we hold i_mutex.
1209		 *
1210		 * Add inode to orphan list in case we crash before
1211		 * truncate finishes
1212		 */
1213		if (extended && ext4_can_truncate(inode))
1214			ext4_orphan_add(handle, inode);
1215
1216		ext4_journal_stop(handle);
1217		if (extended) {
1218			ext4_truncate_failed_write(inode);
1219			/*
1220			 * If truncate failed early the inode might
1221			 * still be on the orphan list; we need to
1222			 * make sure the inode is removed from the
1223			 * orphan list in that case.
1224			 */
1225			if (inode->i_nlink)
1226				ext4_orphan_del(NULL, inode);
1227		}
1228
1229		if (ret == -ENOSPC &&
1230		    ext4_should_retry_alloc(inode->i_sb, &retries))
1231			goto retry_journal;
1232		put_page(page);
1233		return ret;
1234	}
1235	*pagep = page;
1236	return ret;
1237}
1238
1239/* For write_end() in data=journal mode */
1240static int write_end_fn(handle_t *handle, struct buffer_head *bh)
 
1241{
1242	int ret;
1243	if (!buffer_mapped(bh) || buffer_freed(bh))
1244		return 0;
1245	set_buffer_uptodate(bh);
1246	ret = ext4_handle_dirty_metadata(handle, NULL, bh);
1247	clear_buffer_meta(bh);
1248	clear_buffer_prio(bh);
1249	return ret;
1250}
1251
1252/*
1253 * We need to pick up the new inode size which generic_commit_write gave us
1254 * `file' can be NULL - eg, when called from page_symlink().
1255 *
1256 * ext4 never places buffers on inode->i_mapping->private_list.  metadata
1257 * buffers are managed internally.
1258 */
1259static int ext4_write_end(struct file *file,
1260			  struct address_space *mapping,
1261			  loff_t pos, unsigned len, unsigned copied,
1262			  struct page *page, void *fsdata)
1263{
1264	handle_t *handle = ext4_journal_current_handle();
1265	struct inode *inode = mapping->host;
1266	loff_t old_size = inode->i_size;
1267	int ret = 0, ret2;
1268	int i_size_changed = 0;
1269	int inline_data = ext4_has_inline_data(inode);
1270	bool verity = ext4_verity_in_progress(inode);
1271
1272	trace_ext4_write_end(inode, pos, len, copied);
1273	if (inline_data) {
1274		ret = ext4_write_inline_data_end(inode, pos, len,
1275						 copied, page);
1276		if (ret < 0) {
1277			unlock_page(page);
1278			put_page(page);
1279			goto errout;
1280		}
1281		copied = ret;
1282	} else
1283		copied = block_write_end(file, mapping, pos,
1284					 len, copied, page, fsdata);
1285	/*
1286	 * it's important to update i_size while still holding page lock:
1287	 * page writeout could otherwise come in and zero beyond i_size.
1288	 *
1289	 * If FS_IOC_ENABLE_VERITY is running on this inode, then Merkle tree
1290	 * blocks are being written past EOF, so skip the i_size update.
1291	 */
1292	if (!verity)
1293		i_size_changed = ext4_update_inode_size(inode, pos + copied);
1294	unlock_page(page);
1295	put_page(page);
1296
1297	if (old_size < pos && !verity)
1298		pagecache_isize_extended(inode, old_size, pos);
1299	/*
1300	 * Don't mark the inode dirty under page lock. First, it unnecessarily
1301	 * makes the holding time of page lock longer. Second, it forces lock
1302	 * ordering of page lock and transaction start for journaling
1303	 * filesystems.
1304	 */
1305	if (i_size_changed || inline_data)
1306		ret = ext4_mark_inode_dirty(handle, inode);
1307
1308	if (pos + len > inode->i_size && !verity && ext4_can_truncate(inode))
1309		/* if we have allocated more blocks and copied
1310		 * less. We will have blocks allocated outside
1311		 * inode->i_size. So truncate them
1312		 */
1313		ext4_orphan_add(handle, inode);
1314errout:
1315	ret2 = ext4_journal_stop(handle);
1316	if (!ret)
1317		ret = ret2;
1318
1319	if (pos + len > inode->i_size && !verity) {
1320		ext4_truncate_failed_write(inode);
1321		/*
1322		 * If truncate failed early the inode might still be
1323		 * on the orphan list; we need to make sure the inode
1324		 * is removed from the orphan list in that case.
1325		 */
1326		if (inode->i_nlink)
1327			ext4_orphan_del(NULL, inode);
1328	}
1329
1330	return ret ? ret : copied;
1331}
1332
1333/*
1334 * This is a private version of page_zero_new_buffers() which doesn't
1335 * set the buffer to be dirty, since in data=journalled mode we need
1336 * to call ext4_handle_dirty_metadata() instead.
1337 */
1338static void ext4_journalled_zero_new_buffers(handle_t *handle,
 
1339					    struct page *page,
1340					    unsigned from, unsigned to)
1341{
1342	unsigned int block_start = 0, block_end;
1343	struct buffer_head *head, *bh;
1344
1345	bh = head = page_buffers(page);
1346	do {
1347		block_end = block_start + bh->b_size;
1348		if (buffer_new(bh)) {
1349			if (block_end > from && block_start < to) {
1350				if (!PageUptodate(page)) {
1351					unsigned start, size;
1352
1353					start = max(from, block_start);
1354					size = min(to, block_end) - start;
1355
1356					zero_user(page, start, size);
1357					write_end_fn(handle, bh);
1358				}
1359				clear_buffer_new(bh);
1360			}
1361		}
1362		block_start = block_end;
1363		bh = bh->b_this_page;
1364	} while (bh != head);
1365}
1366
1367static int ext4_journalled_write_end(struct file *file,
1368				     struct address_space *mapping,
1369				     loff_t pos, unsigned len, unsigned copied,
1370				     struct page *page, void *fsdata)
1371{
1372	handle_t *handle = ext4_journal_current_handle();
1373	struct inode *inode = mapping->host;
1374	loff_t old_size = inode->i_size;
1375	int ret = 0, ret2;
1376	int partial = 0;
1377	unsigned from, to;
1378	int size_changed = 0;
1379	int inline_data = ext4_has_inline_data(inode);
1380	bool verity = ext4_verity_in_progress(inode);
1381
1382	trace_ext4_journalled_write_end(inode, pos, len, copied);
1383	from = pos & (PAGE_SIZE - 1);
1384	to = from + len;
1385
1386	BUG_ON(!ext4_handle_valid(handle));
1387
1388	if (inline_data) {
1389		ret = ext4_write_inline_data_end(inode, pos, len,
1390						 copied, page);
1391		if (ret < 0) {
1392			unlock_page(page);
1393			put_page(page);
1394			goto errout;
1395		}
1396		copied = ret;
1397	} else if (unlikely(copied < len) && !PageUptodate(page)) {
1398		copied = 0;
1399		ext4_journalled_zero_new_buffers(handle, page, from, to);
1400	} else {
1401		if (unlikely(copied < len))
1402			ext4_journalled_zero_new_buffers(handle, page,
1403							 from + copied, to);
1404		ret = ext4_walk_page_buffers(handle, page_buffers(page), from,
1405					     from + copied, &partial,
1406					     write_end_fn);
1407		if (!partial)
1408			SetPageUptodate(page);
1409	}
1410	if (!verity)
1411		size_changed = ext4_update_inode_size(inode, pos + copied);
1412	ext4_set_inode_state(inode, EXT4_STATE_JDATA);
1413	EXT4_I(inode)->i_datasync_tid = handle->h_transaction->t_tid;
1414	unlock_page(page);
1415	put_page(page);
1416
1417	if (old_size < pos && !verity)
1418		pagecache_isize_extended(inode, old_size, pos);
1419
1420	if (size_changed || inline_data) {
1421		ret2 = ext4_mark_inode_dirty(handle, inode);
1422		if (!ret)
1423			ret = ret2;
1424	}
1425
1426	if (pos + len > inode->i_size && !verity && ext4_can_truncate(inode))
1427		/* if we have allocated more blocks and copied
1428		 * less. We will have blocks allocated outside
1429		 * inode->i_size. So truncate them
1430		 */
1431		ext4_orphan_add(handle, inode);
1432
1433errout:
1434	ret2 = ext4_journal_stop(handle);
1435	if (!ret)
1436		ret = ret2;
1437	if (pos + len > inode->i_size && !verity) {
1438		ext4_truncate_failed_write(inode);
1439		/*
1440		 * If truncate failed early the inode might still be
1441		 * on the orphan list; we need to make sure the inode
1442		 * is removed from the orphan list in that case.
1443		 */
1444		if (inode->i_nlink)
1445			ext4_orphan_del(NULL, inode);
1446	}
1447
1448	return ret ? ret : copied;
1449}
1450
1451/*
1452 * Reserve space for a single cluster
1453 */
1454static int ext4_da_reserve_space(struct inode *inode)
1455{
1456	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
1457	struct ext4_inode_info *ei = EXT4_I(inode);
1458	int ret;
1459
1460	/*
1461	 * We will charge metadata quota at writeout time; this saves
1462	 * us from metadata over-estimation, though we may go over by
1463	 * a small amount in the end.  Here we just reserve for data.
1464	 */
1465	ret = dquot_reserve_block(inode, EXT4_C2B(sbi, 1));
1466	if (ret)
1467		return ret;
1468
1469	spin_lock(&ei->i_block_reservation_lock);
1470	if (ext4_claim_free_clusters(sbi, 1, 0)) {
1471		spin_unlock(&ei->i_block_reservation_lock);
1472		dquot_release_reservation_block(inode, EXT4_C2B(sbi, 1));
1473		return -ENOSPC;
1474	}
1475	ei->i_reserved_data_blocks++;
1476	trace_ext4_da_reserve_space(inode);
1477	spin_unlock(&ei->i_block_reservation_lock);
1478
1479	return 0;       /* success */
1480}
1481
1482void ext4_da_release_space(struct inode *inode, int to_free)
1483{
1484	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
1485	struct ext4_inode_info *ei = EXT4_I(inode);
1486
1487	if (!to_free)
1488		return;		/* Nothing to release, exit */
1489
1490	spin_lock(&EXT4_I(inode)->i_block_reservation_lock);
1491
1492	trace_ext4_da_release_space(inode, to_free);
1493	if (unlikely(to_free > ei->i_reserved_data_blocks)) {
1494		/*
1495		 * if there aren't enough reserved blocks, then the
1496		 * counter is messed up somewhere.  Since this
1497		 * function is called from invalidate page, it's
1498		 * harmless to return without any action.
1499		 */
1500		ext4_warning(inode->i_sb, "ext4_da_release_space: "
1501			 "ino %lu, to_free %d with only %d reserved "
1502			 "data blocks", inode->i_ino, to_free,
1503			 ei->i_reserved_data_blocks);
1504		WARN_ON(1);
1505		to_free = ei->i_reserved_data_blocks;
1506	}
1507	ei->i_reserved_data_blocks -= to_free;
1508
1509	/* update fs dirty data blocks counter */
1510	percpu_counter_sub(&sbi->s_dirtyclusters_counter, to_free);
1511
1512	spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
1513
1514	dquot_release_reservation_block(inode, EXT4_C2B(sbi, to_free));
1515}
1516
1517/*
1518 * Delayed allocation stuff
1519 */
1520
1521struct mpage_da_data {
 
1522	struct inode *inode;
1523	struct writeback_control *wbc;
 
1524
 
1525	pgoff_t first_page;	/* The first page to write */
1526	pgoff_t next_page;	/* Current page to examine */
1527	pgoff_t last_page;	/* Last page to examine */
1528	/*
1529	 * Extent to map - this can be after first_page because that can be
1530	 * fully mapped. We somewhat abuse m_flags to store whether the extent
1531	 * is delalloc or unwritten.
1532	 */
1533	struct ext4_map_blocks map;
1534	struct ext4_io_submit io_submit;	/* IO submission data */
1535	unsigned int do_map:1;
1536	unsigned int scanned_until_end:1;
1537};
1538
1539static void mpage_release_unused_pages(struct mpage_da_data *mpd,
1540				       bool invalidate)
1541{
1542	int nr_pages, i;
1543	pgoff_t index, end;
1544	struct pagevec pvec;
1545	struct inode *inode = mpd->inode;
1546	struct address_space *mapping = inode->i_mapping;
1547
1548	/* This is necessary when next_page == 0. */
1549	if (mpd->first_page >= mpd->next_page)
1550		return;
1551
1552	mpd->scanned_until_end = 0;
1553	index = mpd->first_page;
1554	end   = mpd->next_page - 1;
1555	if (invalidate) {
1556		ext4_lblk_t start, last;
1557		start = index << (PAGE_SHIFT - inode->i_blkbits);
1558		last = end << (PAGE_SHIFT - inode->i_blkbits);
 
 
 
 
 
 
1559		ext4_es_remove_extent(inode, start, last - start + 1);
 
1560	}
1561
1562	pagevec_init(&pvec);
1563	while (index <= end) {
1564		nr_pages = pagevec_lookup_range(&pvec, mapping, &index, end);
1565		if (nr_pages == 0)
1566			break;
1567		for (i = 0; i < nr_pages; i++) {
1568			struct page *page = pvec.pages[i];
1569
1570			BUG_ON(!PageLocked(page));
1571			BUG_ON(PageWriteback(page));
 
 
 
 
1572			if (invalidate) {
1573				if (page_mapped(page))
1574					clear_page_dirty_for_io(page);
1575				block_invalidatepage(page, 0, PAGE_SIZE);
1576				ClearPageUptodate(page);
 
1577			}
1578			unlock_page(page);
1579		}
1580		pagevec_release(&pvec);
1581	}
1582}
1583
1584static void ext4_print_free_blocks(struct inode *inode)
1585{
1586	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
1587	struct super_block *sb = inode->i_sb;
1588	struct ext4_inode_info *ei = EXT4_I(inode);
1589
1590	ext4_msg(sb, KERN_CRIT, "Total free blocks count %lld",
1591	       EXT4_C2B(EXT4_SB(inode->i_sb),
1592			ext4_count_free_clusters(sb)));
1593	ext4_msg(sb, KERN_CRIT, "Free/Dirty block details");
1594	ext4_msg(sb, KERN_CRIT, "free_blocks=%lld",
1595	       (long long) EXT4_C2B(EXT4_SB(sb),
1596		percpu_counter_sum(&sbi->s_freeclusters_counter)));
1597	ext4_msg(sb, KERN_CRIT, "dirty_blocks=%lld",
1598	       (long long) EXT4_C2B(EXT4_SB(sb),
1599		percpu_counter_sum(&sbi->s_dirtyclusters_counter)));
1600	ext4_msg(sb, KERN_CRIT, "Block reservation details");
1601	ext4_msg(sb, KERN_CRIT, "i_reserved_data_blocks=%u",
1602		 ei->i_reserved_data_blocks);
1603	return;
1604}
1605
1606static int ext4_bh_delay_or_unwritten(handle_t *handle, struct buffer_head *bh)
 
1607{
1608	return (buffer_delay(bh) || buffer_unwritten(bh)) && buffer_dirty(bh);
1609}
1610
1611/*
1612 * ext4_insert_delayed_block - adds a delayed block to the extents status
1613 *                             tree, incrementing the reserved cluster/block
1614 *                             count or making a pending reservation
1615 *                             where needed
1616 *
1617 * @inode - file containing the newly added block
1618 * @lblk - logical block to be added
1619 *
1620 * Returns 0 on success, negative error code on failure.
1621 */
1622static int ext4_insert_delayed_block(struct inode *inode, ext4_lblk_t lblk)
1623{
1624	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
1625	int ret;
1626	bool allocated = false;
 
1627
1628	/*
1629	 * If the cluster containing lblk is shared with a delayed,
1630	 * written, or unwritten extent in a bigalloc file system, it's
1631	 * already been accounted for and does not need to be reserved.
1632	 * A pending reservation must be made for the cluster if it's
1633	 * shared with a written or unwritten extent and doesn't already
1634	 * have one.  Written and unwritten extents can be purged from the
1635	 * extents status tree if the system is under memory pressure, so
1636	 * it's necessary to examine the extent tree if a search of the
1637	 * extents status tree doesn't get a match.
1638	 */
1639	if (sbi->s_cluster_ratio == 1) {
1640		ret = ext4_da_reserve_space(inode);
1641		if (ret != 0)   /* ENOSPC */
1642			goto errout;
 
1643	} else {   /* bigalloc */
1644		if (!ext4_es_scan_clu(inode, &ext4_es_is_delonly, lblk)) {
1645			if (!ext4_es_scan_clu(inode,
1646					      &ext4_es_is_mapped, lblk)) {
1647				ret = ext4_clu_mapped(inode,
1648						      EXT4_B2C(sbi, lblk));
1649				if (ret < 0)
1650					goto errout;
1651				if (ret == 0) {
1652					ret = ext4_da_reserve_space(inode);
1653					if (ret != 0)   /* ENOSPC */
1654						goto errout;
 
1655				} else {
1656					allocated = true;
1657				}
1658			} else {
1659				allocated = true;
1660			}
1661		}
1662	}
1663
1664	ret = ext4_es_insert_delayed_block(inode, lblk, allocated);
 
 
1665
1666errout:
1667	return ret;
1668}
1669
1670/*
1671 * This function is grabs code from the very beginning of
1672 * ext4_map_blocks, but assumes that the caller is from delayed write
1673 * time. This function looks up the requested blocks and sets the
1674 * buffer delay bit under the protection of i_data_sem.
1675 */
1676static int ext4_da_map_blocks(struct inode *inode, sector_t iblock,
1677			      struct ext4_map_blocks *map,
1678			      struct buffer_head *bh)
1679{
1680	struct extent_status es;
1681	int retval;
1682	sector_t invalid_block = ~((sector_t) 0xffff);
1683#ifdef ES_AGGRESSIVE_TEST
1684	struct ext4_map_blocks orig_map;
1685
1686	memcpy(&orig_map, map, sizeof(*map));
1687#endif
1688
1689	if (invalid_block < ext4_blocks_count(EXT4_SB(inode->i_sb)->s_es))
1690		invalid_block = ~0;
1691
1692	map->m_flags = 0;
1693	ext_debug(inode, "max_blocks %u, logical block %lu\n", map->m_len,
1694		  (unsigned long) map->m_lblk);
1695
1696	/* Lookup extent status tree firstly */
1697	if (ext4_es_lookup_extent(inode, iblock, NULL, &es)) {
1698		if (ext4_es_is_hole(&es)) {
1699			retval = 0;
1700			down_read(&EXT4_I(inode)->i_data_sem);
1701			goto add_delayed;
1702		}
1703
1704		/*
1705		 * Delayed extent could be allocated by fallocate.
1706		 * So we need to check it.
1707		 */
1708		if (ext4_es_is_delayed(&es) && !ext4_es_is_unwritten(&es)) {
1709			map_bh(bh, inode->i_sb, invalid_block);
1710			set_buffer_new(bh);
1711			set_buffer_delay(bh);
1712			return 0;
1713		}
1714
1715		map->m_pblk = ext4_es_pblock(&es) + iblock - es.es_lblk;
1716		retval = es.es_len - (iblock - es.es_lblk);
1717		if (retval > map->m_len)
1718			retval = map->m_len;
1719		map->m_len = retval;
1720		if (ext4_es_is_written(&es))
1721			map->m_flags |= EXT4_MAP_MAPPED;
1722		else if (ext4_es_is_unwritten(&es))
1723			map->m_flags |= EXT4_MAP_UNWRITTEN;
1724		else
1725			BUG();
1726
1727#ifdef ES_AGGRESSIVE_TEST
1728		ext4_map_blocks_es_recheck(NULL, inode, map, &orig_map, 0);
1729#endif
1730		return retval;
1731	}
1732
1733	/*
1734	 * Try to see if we can get the block without requesting a new
1735	 * file system block.
1736	 */
1737	down_read(&EXT4_I(inode)->i_data_sem);
1738	if (ext4_has_inline_data(inode))
1739		retval = 0;
1740	else if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
1741		retval = ext4_ext_map_blocks(NULL, inode, map, 0);
1742	else
1743		retval = ext4_ind_map_blocks(NULL, inode, map, 0);
1744
1745add_delayed:
1746	if (retval == 0) {
1747		int ret;
1748
1749		/*
1750		 * XXX: __block_prepare_write() unmaps passed block,
1751		 * is it OK?
1752		 */
1753
1754		ret = ext4_insert_delayed_block(inode, map->m_lblk);
1755		if (ret != 0) {
1756			retval = ret;
1757			goto out_unlock;
1758		}
1759
1760		map_bh(bh, inode->i_sb, invalid_block);
1761		set_buffer_new(bh);
1762		set_buffer_delay(bh);
1763	} else if (retval > 0) {
1764		int ret;
1765		unsigned int status;
1766
1767		if (unlikely(retval != map->m_len)) {
1768			ext4_warning(inode->i_sb,
1769				     "ES len assertion failed for inode "
1770				     "%lu: retval %d != map->m_len %d",
1771				     inode->i_ino, retval, map->m_len);
1772			WARN_ON(1);
1773		}
1774
1775		status = map->m_flags & EXT4_MAP_UNWRITTEN ?
1776				EXTENT_STATUS_UNWRITTEN : EXTENT_STATUS_WRITTEN;
1777		ret = ext4_es_insert_extent(inode, map->m_lblk, map->m_len,
1778					    map->m_pblk, status);
1779		if (ret != 0)
1780			retval = ret;
1781	}
1782
1783out_unlock:
1784	up_read((&EXT4_I(inode)->i_data_sem));
1785
1786	return retval;
1787}
1788
1789/*
1790 * This is a special get_block_t callback which is used by
1791 * ext4_da_write_begin().  It will either return mapped block or
1792 * reserve space for a single block.
1793 *
1794 * For delayed buffer_head we have BH_Mapped, BH_New, BH_Delay set.
1795 * We also have b_blocknr = -1 and b_bdev initialized properly
1796 *
1797 * For unwritten buffer_head we have BH_Mapped, BH_New, BH_Unwritten set.
1798 * We also have b_blocknr = physicalblock mapping unwritten extent and b_bdev
1799 * initialized properly.
1800 */
1801int ext4_da_get_block_prep(struct inode *inode, sector_t iblock,
1802			   struct buffer_head *bh, int create)
1803{
1804	struct ext4_map_blocks map;
1805	int ret = 0;
1806
1807	BUG_ON(create == 0);
1808	BUG_ON(bh->b_size != inode->i_sb->s_blocksize);
1809
1810	map.m_lblk = iblock;
1811	map.m_len = 1;
1812
1813	/*
1814	 * first, we need to know whether the block is allocated already
1815	 * preallocated blocks are unmapped but should treated
1816	 * the same as allocated blocks.
1817	 */
1818	ret = ext4_da_map_blocks(inode, iblock, &map, bh);
1819	if (ret <= 0)
1820		return ret;
1821
1822	map_bh(bh, inode->i_sb, map.m_pblk);
1823	ext4_update_bh_state(bh, map.m_flags);
1824
1825	if (buffer_unwritten(bh)) {
1826		/* A delayed write to unwritten bh should be marked
1827		 * new and mapped.  Mapped ensures that we don't do
1828		 * get_block multiple times when we write to the same
1829		 * offset and new ensures that we do proper zero out
1830		 * for partial write.
1831		 */
1832		set_buffer_new(bh);
1833		set_buffer_mapped(bh);
1834	}
1835	return 0;
1836}
1837
1838static int bget_one(handle_t *handle, struct buffer_head *bh)
1839{
1840	get_bh(bh);
1841	return 0;
1842}
1843
1844static int bput_one(handle_t *handle, struct buffer_head *bh)
1845{
1846	put_bh(bh);
1847	return 0;
1848}
1849
1850static int __ext4_journalled_writepage(struct page *page,
1851				       unsigned int len)
1852{
1853	struct address_space *mapping = page->mapping;
1854	struct inode *inode = mapping->host;
1855	struct buffer_head *page_bufs = NULL;
1856	handle_t *handle = NULL;
1857	int ret = 0, err = 0;
1858	int inline_data = ext4_has_inline_data(inode);
1859	struct buffer_head *inode_bh = NULL;
 
1860
1861	ClearPageChecked(page);
1862
1863	if (inline_data) {
1864		BUG_ON(page->index != 0);
1865		BUG_ON(len > ext4_get_max_inline_size(inode));
1866		inode_bh = ext4_journalled_write_inline_data(inode, len, page);
1867		if (inode_bh == NULL)
1868			goto out;
1869	} else {
1870		page_bufs = page_buffers(page);
1871		if (!page_bufs) {
1872			BUG();
1873			goto out;
1874		}
1875		ext4_walk_page_buffers(handle, page_bufs, 0, len,
1876				       NULL, bget_one);
1877	}
1878	/*
1879	 * We need to release the page lock before we start the
1880	 * journal, so grab a reference so the page won't disappear
1881	 * out from under us.
1882	 */
1883	get_page(page);
1884	unlock_page(page);
1885
1886	handle = ext4_journal_start(inode, EXT4_HT_WRITE_PAGE,
1887				    ext4_writepage_trans_blocks(inode));
1888	if (IS_ERR(handle)) {
1889		ret = PTR_ERR(handle);
1890		put_page(page);
1891		goto out_no_pagelock;
1892	}
1893	BUG_ON(!ext4_handle_valid(handle));
1894
1895	lock_page(page);
1896	put_page(page);
1897	if (page->mapping != mapping) {
 
1898		/* The page got truncated from under us */
1899		ext4_journal_stop(handle);
1900		ret = 0;
1901		goto out;
1902	}
1903
1904	if (inline_data) {
1905		ret = ext4_mark_inode_dirty(handle, inode);
1906	} else {
1907		ret = ext4_walk_page_buffers(handle, page_bufs, 0, len, NULL,
1908					     do_journal_get_write_access);
1909
1910		err = ext4_walk_page_buffers(handle, page_bufs, 0, len, NULL,
1911					     write_end_fn);
 
 
 
 
 
 
 
 
1912	}
1913	if (ret == 0)
1914		ret = err;
 
 
 
1915	EXT4_I(inode)->i_datasync_tid = handle->h_transaction->t_tid;
1916	err = ext4_journal_stop(handle);
1917	if (!ret)
1918		ret = err;
1919
1920	if (!ext4_has_inline_data(inode))
1921		ext4_walk_page_buffers(NULL, page_bufs, 0, len,
1922				       NULL, bput_one);
1923	ext4_set_inode_state(inode, EXT4_STATE_JDATA);
1924out:
1925	unlock_page(page);
1926out_no_pagelock:
1927	brelse(inode_bh);
1928	return ret;
1929}
1930
1931/*
1932 * Note that we don't need to start a transaction unless we're journaling data
1933 * because we should have holes filled from ext4_page_mkwrite(). We even don't
1934 * need to file the inode to the transaction's list in ordered mode because if
1935 * we are writing back data added by write(), the inode is already there and if
1936 * we are writing back data modified via mmap(), no one guarantees in which
1937 * transaction the data will hit the disk. In case we are journaling data, we
1938 * cannot start transaction directly because transaction start ranks above page
1939 * lock so we have to do some magic.
1940 *
1941 * This function can get called via...
1942 *   - ext4_writepages after taking page lock (have journal handle)
1943 *   - journal_submit_inode_data_buffers (no journal handle)
1944 *   - shrink_page_list via the kswapd/direct reclaim (no journal handle)
1945 *   - grab_page_cache when doing write_begin (have journal handle)
1946 *
1947 * We don't do any block allocation in this function. If we have page with
1948 * multiple blocks we need to write those buffer_heads that are mapped. This
1949 * is important for mmaped based write. So if we do with blocksize 1K
1950 * truncate(f, 1024);
1951 * a = mmap(f, 0, 4096);
1952 * a[0] = 'a';
1953 * truncate(f, 4096);
1954 * we have in the page first buffer_head mapped via page_mkwrite call back
1955 * but other buffer_heads would be unmapped but dirty (dirty done via the
1956 * do_wp_page). So writepage should write the first block. If we modify
1957 * the mmap area beyond 1024 we will again get a page_fault and the
1958 * page_mkwrite callback will do the block allocation and mark the
1959 * buffer_heads mapped.
1960 *
1961 * We redirty the page if we have any buffer_heads that is either delay or
1962 * unwritten in the page.
1963 *
1964 * We can get recursively called as show below.
1965 *
1966 *	ext4_writepage() -> kmalloc() -> __alloc_pages() -> page_launder() ->
1967 *		ext4_writepage()
1968 *
1969 * But since we don't do any block allocation we should not deadlock.
1970 * Page also have the dirty flag cleared so we don't get recurive page_lock.
1971 */
1972static int ext4_writepage(struct page *page,
1973			  struct writeback_control *wbc)
1974{
 
1975	int ret = 0;
1976	loff_t size;
1977	unsigned int len;
1978	struct buffer_head *page_bufs = NULL;
1979	struct inode *inode = page->mapping->host;
1980	struct ext4_io_submit io_submit;
1981	bool keep_towrite = false;
1982
1983	if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb)))) {
1984		inode->i_mapping->a_ops->invalidatepage(page, 0, PAGE_SIZE);
1985		unlock_page(page);
1986		return -EIO;
1987	}
1988
1989	trace_ext4_writepage(page);
1990	size = i_size_read(inode);
1991	if (page->index == size >> PAGE_SHIFT &&
1992	    !ext4_verity_in_progress(inode))
1993		len = size & ~PAGE_MASK;
1994	else
1995		len = PAGE_SIZE;
1996
 
 
 
 
 
 
 
 
 
1997	page_bufs = page_buffers(page);
1998	/*
1999	 * We cannot do block allocation or other extent handling in this
2000	 * function. If there are buffers needing that, we have to redirty
2001	 * the page. But we may reach here when we do a journal commit via
2002	 * journal_submit_inode_data_buffers() and in that case we must write
2003	 * allocated buffers to achieve data=ordered mode guarantees.
2004	 *
2005	 * Also, if there is only one buffer per page (the fs block
2006	 * size == the page size), if one buffer needs block
2007	 * allocation or needs to modify the extent tree to clear the
2008	 * unwritten flag, we know that the page can't be written at
2009	 * all, so we might as well refuse the write immediately.
2010	 * Unfortunately if the block size != page size, we can't as
2011	 * easily detect this case using ext4_walk_page_buffers(), but
2012	 * for the extremely common case, this is an optimization that
2013	 * skips a useless round trip through ext4_bio_write_page().
2014	 */
2015	if (ext4_walk_page_buffers(NULL, page_bufs, 0, len, NULL,
2016				   ext4_bh_delay_or_unwritten)) {
2017		redirty_page_for_writepage(wbc, page);
2018		if ((current->flags & PF_MEMALLOC) ||
2019		    (inode->i_sb->s_blocksize == PAGE_SIZE)) {
2020			/*
2021			 * For memory cleaning there's no point in writing only
2022			 * some buffers. So just bail out. Warn if we came here
2023			 * from direct reclaim.
2024			 */
2025			WARN_ON_ONCE((current->flags & (PF_MEMALLOC|PF_KSWAPD))
2026							== PF_MEMALLOC);
2027			unlock_page(page);
2028			return 0;
2029		}
2030		keep_towrite = true;
2031	}
2032
2033	if (PageChecked(page) && ext4_should_journal_data(inode))
2034		/*
2035		 * It's mmapped pagecache.  Add buffers and journal it.  There
2036		 * doesn't seem much point in redirtying the page here.
2037		 */
2038		return __ext4_journalled_writepage(page, len);
2039
2040	ext4_io_submit_init(&io_submit, wbc);
2041	io_submit.io_end = ext4_init_io_end(inode, GFP_NOFS);
2042	if (!io_submit.io_end) {
2043		redirty_page_for_writepage(wbc, page);
2044		unlock_page(page);
2045		return -ENOMEM;
2046	}
2047	ret = ext4_bio_write_page(&io_submit, page, len, wbc, keep_towrite);
2048	ext4_io_submit(&io_submit);
2049	/* Drop io_end reference we got from init */
2050	ext4_put_io_end_defer(io_submit.io_end);
2051	return ret;
2052}
2053
2054static int mpage_submit_page(struct mpage_da_data *mpd, struct page *page)
2055{
2056	int len;
2057	loff_t size;
2058	int err;
2059
2060	BUG_ON(page->index != mpd->first_page);
2061	clear_page_dirty_for_io(page);
2062	/*
2063	 * We have to be very careful here!  Nothing protects writeback path
2064	 * against i_size changes and the page can be writeably mapped into
2065	 * page tables. So an application can be growing i_size and writing
2066	 * data through mmap while writeback runs. clear_page_dirty_for_io()
2067	 * write-protects our page in page tables and the page cannot get
2068	 * written to again until we release page lock. So only after
2069	 * clear_page_dirty_for_io() we are safe to sample i_size for
2070	 * ext4_bio_write_page() to zero-out tail of the written page. We rely
2071	 * on the barrier provided by TestClearPageDirty in
2072	 * clear_page_dirty_for_io() to make sure i_size is really sampled only
2073	 * after page tables are updated.
2074	 */
2075	size = i_size_read(mpd->inode);
2076	if (page->index == size >> PAGE_SHIFT &&
2077	    !ext4_verity_in_progress(mpd->inode))
2078		len = size & ~PAGE_MASK;
2079	else
2080		len = PAGE_SIZE;
2081	err = ext4_bio_write_page(&mpd->io_submit, page, len, mpd->wbc, false);
2082	if (!err)
2083		mpd->wbc->nr_to_write--;
2084	mpd->first_page++;
2085
2086	return err;
2087}
2088
2089#define BH_FLAGS (BIT(BH_Unwritten) | BIT(BH_Delay))
2090
2091/*
2092 * mballoc gives us at most this number of blocks...
2093 * XXX: That seems to be only a limitation of ext4_mb_normalize_request().
2094 * The rest of mballoc seems to handle chunks up to full group size.
2095 */
2096#define MAX_WRITEPAGES_EXTENT_LEN 2048
2097
2098/*
2099 * mpage_add_bh_to_extent - try to add bh to extent of blocks to map
2100 *
2101 * @mpd - extent of blocks
2102 * @lblk - logical number of the block in the file
2103 * @bh - buffer head we want to add to the extent
2104 *
2105 * The function is used to collect contig. blocks in the same state. If the
2106 * buffer doesn't require mapping for writeback and we haven't started the
2107 * extent of buffers to map yet, the function returns 'true' immediately - the
2108 * caller can write the buffer right away. Otherwise the function returns true
2109 * if the block has been added to the extent, false if the block couldn't be
2110 * added.
2111 */
2112static bool mpage_add_bh_to_extent(struct mpage_da_data *mpd, ext4_lblk_t lblk,
2113				   struct buffer_head *bh)
2114{
2115	struct ext4_map_blocks *map = &mpd->map;
2116
2117	/* Buffer that doesn't need mapping for writeback? */
2118	if (!buffer_dirty(bh) || !buffer_mapped(bh) ||
2119	    (!buffer_delay(bh) && !buffer_unwritten(bh))) {
2120		/* So far no extent to map => we write the buffer right away */
2121		if (map->m_len == 0)
2122			return true;
2123		return false;
2124	}
2125
2126	/* First block in the extent? */
2127	if (map->m_len == 0) {
2128		/* We cannot map unless handle is started... */
2129		if (!mpd->do_map)
2130			return false;
2131		map->m_lblk = lblk;
2132		map->m_len = 1;
2133		map->m_flags = bh->b_state & BH_FLAGS;
2134		return true;
2135	}
2136
2137	/* Don't go larger than mballoc is willing to allocate */
2138	if (map->m_len >= MAX_WRITEPAGES_EXTENT_LEN)
2139		return false;
2140
2141	/* Can we merge the block to our big extent? */
2142	if (lblk == map->m_lblk + map->m_len &&
2143	    (bh->b_state & BH_FLAGS) == map->m_flags) {
2144		map->m_len++;
2145		return true;
2146	}
2147	return false;
2148}
2149
2150/*
2151 * mpage_process_page_bufs - submit page buffers for IO or add them to extent
2152 *
2153 * @mpd - extent of blocks for mapping
2154 * @head - the first buffer in the page
2155 * @bh - buffer we should start processing from
2156 * @lblk - logical number of the block in the file corresponding to @bh
2157 *
2158 * Walk through page buffers from @bh upto @head (exclusive) and either submit
2159 * the page for IO if all buffers in this page were mapped and there's no
2160 * accumulated extent of buffers to map or add buffers in the page to the
2161 * extent of buffers to map. The function returns 1 if the caller can continue
2162 * by processing the next page, 0 if it should stop adding buffers to the
2163 * extent to map because we cannot extend it anymore. It can also return value
2164 * < 0 in case of error during IO submission.
2165 */
2166static int mpage_process_page_bufs(struct mpage_da_data *mpd,
2167				   struct buffer_head *head,
2168				   struct buffer_head *bh,
2169				   ext4_lblk_t lblk)
2170{
2171	struct inode *inode = mpd->inode;
2172	int err;
2173	ext4_lblk_t blocks = (i_size_read(inode) + i_blocksize(inode) - 1)
2174							>> inode->i_blkbits;
2175
2176	if (ext4_verity_in_progress(inode))
2177		blocks = EXT_MAX_BLOCKS;
2178
2179	do {
2180		BUG_ON(buffer_locked(bh));
2181
2182		if (lblk >= blocks || !mpage_add_bh_to_extent(mpd, lblk, bh)) {
2183			/* Found extent to map? */
2184			if (mpd->map.m_len)
2185				return 0;
2186			/* Buffer needs mapping and handle is not started? */
2187			if (!mpd->do_map)
2188				return 0;
2189			/* Everything mapped so far and we hit EOF */
2190			break;
2191		}
2192	} while (lblk++, (bh = bh->b_this_page) != head);
2193	/* So far everything mapped? Submit the page for IO. */
2194	if (mpd->map.m_len == 0) {
2195		err = mpage_submit_page(mpd, head->b_page);
2196		if (err < 0)
2197			return err;
2198	}
2199	if (lblk >= blocks) {
2200		mpd->scanned_until_end = 1;
2201		return 0;
2202	}
2203	return 1;
2204}
2205
2206/*
2207 * mpage_process_page - update page buffers corresponding to changed extent and
2208 *		       may submit fully mapped page for IO
2209 *
2210 * @mpd		- description of extent to map, on return next extent to map
2211 * @m_lblk	- logical block mapping.
2212 * @m_pblk	- corresponding physical mapping.
2213 * @map_bh	- determines on return whether this page requires any further
2214 *		  mapping or not.
2215 * Scan given page buffers corresponding to changed extent and update buffer
2216 * state according to new extent state.
2217 * We map delalloc buffers to their physical location, clear unwritten bits.
2218 * If the given page is not fully mapped, we update @map to the next extent in
2219 * the given page that needs mapping & return @map_bh as true.
2220 */
2221static int mpage_process_page(struct mpage_da_data *mpd, struct page *page,
2222			      ext4_lblk_t *m_lblk, ext4_fsblk_t *m_pblk,
2223			      bool *map_bh)
2224{
2225	struct buffer_head *head, *bh;
2226	ext4_io_end_t *io_end = mpd->io_submit.io_end;
2227	ext4_lblk_t lblk = *m_lblk;
2228	ext4_fsblk_t pblock = *m_pblk;
2229	int err = 0;
2230	int blkbits = mpd->inode->i_blkbits;
2231	ssize_t io_end_size = 0;
2232	struct ext4_io_end_vec *io_end_vec = ext4_last_io_end_vec(io_end);
2233
2234	bh = head = page_buffers(page);
2235	do {
2236		if (lblk < mpd->map.m_lblk)
2237			continue;
2238		if (lblk >= mpd->map.m_lblk + mpd->map.m_len) {
2239			/*
2240			 * Buffer after end of mapped extent.
2241			 * Find next buffer in the page to map.
2242			 */
2243			mpd->map.m_len = 0;
2244			mpd->map.m_flags = 0;
2245			io_end_vec->size += io_end_size;
2246			io_end_size = 0;
2247
2248			err = mpage_process_page_bufs(mpd, head, bh, lblk);
2249			if (err > 0)
2250				err = 0;
2251			if (!err && mpd->map.m_len && mpd->map.m_lblk > lblk) {
2252				io_end_vec = ext4_alloc_io_end_vec(io_end);
2253				if (IS_ERR(io_end_vec)) {
2254					err = PTR_ERR(io_end_vec);
2255					goto out;
2256				}
2257				io_end_vec->offset = mpd->map.m_lblk << blkbits;
2258			}
2259			*map_bh = true;
2260			goto out;
2261		}
2262		if (buffer_delay(bh)) {
2263			clear_buffer_delay(bh);
2264			bh->b_blocknr = pblock++;
2265		}
2266		clear_buffer_unwritten(bh);
2267		io_end_size += (1 << blkbits);
2268	} while (lblk++, (bh = bh->b_this_page) != head);
2269
2270	io_end_vec->size += io_end_size;
2271	io_end_size = 0;
2272	*map_bh = false;
2273out:
2274	*m_lblk = lblk;
2275	*m_pblk = pblock;
2276	return err;
2277}
2278
2279/*
2280 * mpage_map_buffers - update buffers corresponding to changed extent and
2281 *		       submit fully mapped pages for IO
2282 *
2283 * @mpd - description of extent to map, on return next extent to map
2284 *
2285 * Scan buffers corresponding to changed extent (we expect corresponding pages
2286 * to be already locked) and update buffer state according to new extent state.
2287 * We map delalloc buffers to their physical location, clear unwritten bits,
2288 * and mark buffers as uninit when we perform writes to unwritten extents
2289 * and do extent conversion after IO is finished. If the last page is not fully
2290 * mapped, we update @map to the next extent in the last page that needs
2291 * mapping. Otherwise we submit the page for IO.
2292 */
2293static int mpage_map_and_submit_buffers(struct mpage_da_data *mpd)
2294{
2295	struct pagevec pvec;
2296	int nr_pages, i;
2297	struct inode *inode = mpd->inode;
2298	int bpp_bits = PAGE_SHIFT - inode->i_blkbits;
2299	pgoff_t start, end;
2300	ext4_lblk_t lblk;
2301	ext4_fsblk_t pblock;
2302	int err;
2303	bool map_bh = false;
2304
2305	start = mpd->map.m_lblk >> bpp_bits;
2306	end = (mpd->map.m_lblk + mpd->map.m_len - 1) >> bpp_bits;
2307	lblk = start << bpp_bits;
2308	pblock = mpd->map.m_pblk;
2309
2310	pagevec_init(&pvec);
2311	while (start <= end) {
2312		nr_pages = pagevec_lookup_range(&pvec, inode->i_mapping,
2313						&start, end);
2314		if (nr_pages == 0)
2315			break;
2316		for (i = 0; i < nr_pages; i++) {
2317			struct page *page = pvec.pages[i];
2318
2319			err = mpage_process_page(mpd, page, &lblk, &pblock,
2320						 &map_bh);
2321			/*
2322			 * If map_bh is true, means page may require further bh
2323			 * mapping, or maybe the page was submitted for IO.
2324			 * So we return to call further extent mapping.
2325			 */
2326			if (err < 0 || map_bh)
2327				goto out;
2328			/* Page fully mapped - let IO run! */
2329			err = mpage_submit_page(mpd, page);
2330			if (err < 0)
2331				goto out;
2332		}
2333		pagevec_release(&pvec);
2334	}
2335	/* Extent fully mapped and matches with page boundary. We are done. */
2336	mpd->map.m_len = 0;
2337	mpd->map.m_flags = 0;
2338	return 0;
2339out:
2340	pagevec_release(&pvec);
2341	return err;
2342}
2343
2344static int mpage_map_one_extent(handle_t *handle, struct mpage_da_data *mpd)
2345{
2346	struct inode *inode = mpd->inode;
2347	struct ext4_map_blocks *map = &mpd->map;
2348	int get_blocks_flags;
2349	int err, dioread_nolock;
2350
2351	trace_ext4_da_write_pages_extent(inode, map);
2352	/*
2353	 * Call ext4_map_blocks() to allocate any delayed allocation blocks, or
2354	 * to convert an unwritten extent to be initialized (in the case
2355	 * where we have written into one or more preallocated blocks).  It is
2356	 * possible that we're going to need more metadata blocks than
2357	 * previously reserved. However we must not fail because we're in
2358	 * writeback and there is nothing we can do about it so it might result
2359	 * in data loss.  So use reserved blocks to allocate metadata if
2360	 * possible.
2361	 *
2362	 * We pass in the magic EXT4_GET_BLOCKS_DELALLOC_RESERVE if
2363	 * the blocks in question are delalloc blocks.  This indicates
2364	 * that the blocks and quotas has already been checked when
2365	 * the data was copied into the page cache.
2366	 */
2367	get_blocks_flags = EXT4_GET_BLOCKS_CREATE |
2368			   EXT4_GET_BLOCKS_METADATA_NOFAIL |
2369			   EXT4_GET_BLOCKS_IO_SUBMIT;
2370	dioread_nolock = ext4_should_dioread_nolock(inode);
2371	if (dioread_nolock)
2372		get_blocks_flags |= EXT4_GET_BLOCKS_IO_CREATE_EXT;
2373	if (map->m_flags & BIT(BH_Delay))
2374		get_blocks_flags |= EXT4_GET_BLOCKS_DELALLOC_RESERVE;
2375
2376	err = ext4_map_blocks(handle, inode, map, get_blocks_flags);
2377	if (err < 0)
2378		return err;
2379	if (dioread_nolock && (map->m_flags & EXT4_MAP_UNWRITTEN)) {
2380		if (!mpd->io_submit.io_end->handle &&
2381		    ext4_handle_valid(handle)) {
2382			mpd->io_submit.io_end->handle = handle->h_rsv_handle;
2383			handle->h_rsv_handle = NULL;
2384		}
2385		ext4_set_io_unwritten_flag(inode, mpd->io_submit.io_end);
2386	}
2387
2388	BUG_ON(map->m_len == 0);
2389	return 0;
2390}
2391
2392/*
2393 * mpage_map_and_submit_extent - map extent starting at mpd->lblk of length
2394 *				 mpd->len and submit pages underlying it for IO
2395 *
2396 * @handle - handle for journal operations
2397 * @mpd - extent to map
2398 * @give_up_on_write - we set this to true iff there is a fatal error and there
2399 *                     is no hope of writing the data. The caller should discard
2400 *                     dirty pages to avoid infinite loops.
2401 *
2402 * The function maps extent starting at mpd->lblk of length mpd->len. If it is
2403 * delayed, blocks are allocated, if it is unwritten, we may need to convert
2404 * them to initialized or split the described range from larger unwritten
2405 * extent. Note that we need not map all the described range since allocation
2406 * can return less blocks or the range is covered by more unwritten extents. We
2407 * cannot map more because we are limited by reserved transaction credits. On
2408 * the other hand we always make sure that the last touched page is fully
2409 * mapped so that it can be written out (and thus forward progress is
2410 * guaranteed). After mapping we submit all mapped pages for IO.
2411 */
2412static int mpage_map_and_submit_extent(handle_t *handle,
2413				       struct mpage_da_data *mpd,
2414				       bool *give_up_on_write)
2415{
2416	struct inode *inode = mpd->inode;
2417	struct ext4_map_blocks *map = &mpd->map;
2418	int err;
2419	loff_t disksize;
2420	int progress = 0;
2421	ext4_io_end_t *io_end = mpd->io_submit.io_end;
2422	struct ext4_io_end_vec *io_end_vec;
2423
2424	io_end_vec = ext4_alloc_io_end_vec(io_end);
2425	if (IS_ERR(io_end_vec))
2426		return PTR_ERR(io_end_vec);
2427	io_end_vec->offset = ((loff_t)map->m_lblk) << inode->i_blkbits;
2428	do {
2429		err = mpage_map_one_extent(handle, mpd);
2430		if (err < 0) {
2431			struct super_block *sb = inode->i_sb;
2432
2433			if (ext4_forced_shutdown(EXT4_SB(sb)) ||
2434			    EXT4_SB(sb)->s_mount_flags & EXT4_MF_FS_ABORTED)
2435				goto invalidate_dirty_pages;
2436			/*
2437			 * Let the uper layers retry transient errors.
2438			 * In the case of ENOSPC, if ext4_count_free_blocks()
2439			 * is non-zero, a commit should free up blocks.
2440			 */
2441			if ((err == -ENOMEM) ||
2442			    (err == -ENOSPC && ext4_count_free_clusters(sb))) {
2443				if (progress)
2444					goto update_disksize;
2445				return err;
2446			}
2447			ext4_msg(sb, KERN_CRIT,
2448				 "Delayed block allocation failed for "
2449				 "inode %lu at logical offset %llu with"
2450				 " max blocks %u with error %d",
2451				 inode->i_ino,
2452				 (unsigned long long)map->m_lblk,
2453				 (unsigned)map->m_len, -err);
2454			ext4_msg(sb, KERN_CRIT,
2455				 "This should not happen!! Data will "
2456				 "be lost\n");
2457			if (err == -ENOSPC)
2458				ext4_print_free_blocks(inode);
2459		invalidate_dirty_pages:
2460			*give_up_on_write = true;
2461			return err;
2462		}
2463		progress = 1;
2464		/*
2465		 * Update buffer state, submit mapped pages, and get us new
2466		 * extent to map
2467		 */
2468		err = mpage_map_and_submit_buffers(mpd);
2469		if (err < 0)
2470			goto update_disksize;
2471	} while (map->m_len);
2472
2473update_disksize:
2474	/*
2475	 * Update on-disk size after IO is submitted.  Races with
2476	 * truncate are avoided by checking i_size under i_data_sem.
2477	 */
2478	disksize = ((loff_t)mpd->first_page) << PAGE_SHIFT;
2479	if (disksize > READ_ONCE(EXT4_I(inode)->i_disksize)) {
2480		int err2;
2481		loff_t i_size;
2482
2483		down_write(&EXT4_I(inode)->i_data_sem);
2484		i_size = i_size_read(inode);
2485		if (disksize > i_size)
2486			disksize = i_size;
2487		if (disksize > EXT4_I(inode)->i_disksize)
2488			EXT4_I(inode)->i_disksize = disksize;
2489		up_write(&EXT4_I(inode)->i_data_sem);
2490		err2 = ext4_mark_inode_dirty(handle, inode);
2491		if (err2) {
2492			ext4_error_err(inode->i_sb, -err2,
2493				       "Failed to mark inode %lu dirty",
2494				       inode->i_ino);
2495		}
2496		if (!err)
2497			err = err2;
2498	}
2499	return err;
2500}
2501
2502/*
2503 * Calculate the total number of credits to reserve for one writepages
2504 * iteration. This is called from ext4_writepages(). We map an extent of
2505 * up to MAX_WRITEPAGES_EXTENT_LEN blocks and then we go on and finish mapping
2506 * the last partial page. So in total we can map MAX_WRITEPAGES_EXTENT_LEN +
2507 * bpp - 1 blocks in bpp different extents.
2508 */
2509static int ext4_da_writepages_trans_blocks(struct inode *inode)
2510{
2511	int bpp = ext4_journal_blocks_per_page(inode);
2512
2513	return ext4_meta_trans_blocks(inode,
2514				MAX_WRITEPAGES_EXTENT_LEN + bpp - 1, bpp);
2515}
2516
 
 
 
 
 
 
 
 
 
 
 
 
 
2517/*
2518 * mpage_prepare_extent_to_map - find & lock contiguous range of dirty pages
2519 * 				 and underlying extent to map
2520 *
2521 * @mpd - where to look for pages
2522 *
2523 * Walk dirty pages in the mapping. If they are fully mapped, submit them for
2524 * IO immediately. When we find a page which isn't mapped we start accumulating
2525 * extent of buffers underlying these pages that needs mapping (formed by
2526 * either delayed or unwritten buffers). We also lock the pages containing
2527 * these buffers. The extent found is returned in @mpd structure (starting at
2528 * mpd->lblk with length mpd->len blocks).
 
 
2529 *
2530 * Note that this function can attach bios to one io_end structure which are
2531 * neither logically nor physically contiguous. Although it may seem as an
2532 * unnecessary complication, it is actually inevitable in blocksize < pagesize
2533 * case as we need to track IO to all buffers underlying a page in one io_end.
2534 */
2535static int mpage_prepare_extent_to_map(struct mpage_da_data *mpd)
2536{
2537	struct address_space *mapping = mpd->inode->i_mapping;
2538	struct pagevec pvec;
2539	unsigned int nr_pages;
2540	long left = mpd->wbc->nr_to_write;
2541	pgoff_t index = mpd->first_page;
2542	pgoff_t end = mpd->last_page;
2543	xa_mark_t tag;
2544	int i, err = 0;
2545	int blkbits = mpd->inode->i_blkbits;
2546	ext4_lblk_t lblk;
2547	struct buffer_head *head;
2548
2549	if (mpd->wbc->sync_mode == WB_SYNC_ALL || mpd->wbc->tagged_writepages)
2550		tag = PAGECACHE_TAG_TOWRITE;
2551	else
2552		tag = PAGECACHE_TAG_DIRTY;
2553
2554	pagevec_init(&pvec);
2555	mpd->map.m_len = 0;
2556	mpd->next_page = index;
2557	while (index <= end) {
2558		nr_pages = pagevec_lookup_range_tag(&pvec, mapping, &index, end,
2559				tag);
2560		if (nr_pages == 0)
2561			break;
2562
2563		for (i = 0; i < nr_pages; i++) {
2564			struct page *page = pvec.pages[i];
2565
2566			/*
2567			 * Accumulated enough dirty pages? This doesn't apply
2568			 * to WB_SYNC_ALL mode. For integrity sync we have to
2569			 * keep going because someone may be concurrently
2570			 * dirtying pages, and we might have synced a lot of
2571			 * newly appeared dirty pages, but have not synced all
2572			 * of the old dirty pages.
2573			 */
2574			if (mpd->wbc->sync_mode == WB_SYNC_NONE && left <= 0)
2575				goto out;
2576
2577			/* If we can't merge this page, we are done. */
2578			if (mpd->map.m_len > 0 && mpd->next_page != page->index)
2579				goto out;
2580
2581			lock_page(page);
2582			/*
2583			 * If the page is no longer dirty, or its mapping no
2584			 * longer corresponds to inode we are writing (which
2585			 * means it has been truncated or invalidated), or the
2586			 * page is already under writeback and we are not doing
2587			 * a data integrity writeback, skip the page
2588			 */
2589			if (!PageDirty(page) ||
2590			    (PageWriteback(page) &&
2591			     (mpd->wbc->sync_mode == WB_SYNC_NONE)) ||
2592			    unlikely(page->mapping != mapping)) {
2593				unlock_page(page);
2594				continue;
2595			}
2596
2597			wait_on_page_writeback(page);
2598			BUG_ON(PageWriteback(page));
2599
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2600			if (mpd->map.m_len == 0)
2601				mpd->first_page = page->index;
2602			mpd->next_page = page->index + 1;
2603			/* Add all dirty buffers to mpd */
2604			lblk = ((ext4_lblk_t)page->index) <<
2605				(PAGE_SHIFT - blkbits);
2606			head = page_buffers(page);
2607			err = mpage_process_page_bufs(mpd, head, head, lblk);
2608			if (err <= 0)
2609				goto out;
2610			err = 0;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2611			left--;
2612		}
2613		pagevec_release(&pvec);
2614		cond_resched();
2615	}
2616	mpd->scanned_until_end = 1;
2617	return 0;
2618out:
2619	pagevec_release(&pvec);
2620	return err;
2621}
2622
2623static int ext4_writepages(struct address_space *mapping,
2624			   struct writeback_control *wbc)
 
 
 
 
 
2625{
 
2626	pgoff_t	writeback_index = 0;
2627	long nr_to_write = wbc->nr_to_write;
2628	int range_whole = 0;
2629	int cycled = 1;
2630	handle_t *handle = NULL;
2631	struct mpage_da_data mpd;
2632	struct inode *inode = mapping->host;
2633	int needed_blocks, rsv_blocks = 0, ret = 0;
2634	struct ext4_sb_info *sbi = EXT4_SB(mapping->host->i_sb);
2635	struct blk_plug plug;
2636	bool give_up_on_write = false;
2637
2638	if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb))))
2639		return -EIO;
2640
2641	percpu_down_read(&sbi->s_writepages_rwsem);
2642	trace_ext4_writepages(inode, wbc);
2643
2644	/*
2645	 * No pages to write? This is mainly a kludge to avoid starting
2646	 * a transaction for special inodes like journal inode on last iput()
2647	 * because that could violate lock ordering on umount
2648	 */
2649	if (!mapping->nrpages || !mapping_tagged(mapping, PAGECACHE_TAG_DIRTY))
2650		goto out_writepages;
2651
2652	if (ext4_should_journal_data(inode)) {
2653		ret = generic_writepages(mapping, wbc);
 
 
2654		goto out_writepages;
2655	}
2656
2657	/*
2658	 * If the filesystem has aborted, it is read-only, so return
2659	 * right away instead of dumping stack traces later on that
2660	 * will obscure the real source of the problem.  We test
2661	 * EXT4_MF_FS_ABORTED instead of sb->s_flag's SB_RDONLY because
2662	 * the latter could be true if the filesystem is mounted
2663	 * read-only, and in that case, ext4_writepages should
2664	 * *never* be called, so if that ever happens, we would want
2665	 * the stack trace.
2666	 */
2667	if (unlikely(ext4_forced_shutdown(EXT4_SB(mapping->host->i_sb)) ||
2668		     sbi->s_mount_flags & EXT4_MF_FS_ABORTED)) {
2669		ret = -EROFS;
2670		goto out_writepages;
2671	}
2672
2673	/*
2674	 * If we have inline data and arrive here, it means that
2675	 * we will soon create the block for the 1st page, so
2676	 * we'd better clear the inline data here.
2677	 */
2678	if (ext4_has_inline_data(inode)) {
2679		/* Just inode will be modified... */
2680		handle = ext4_journal_start(inode, EXT4_HT_INODE, 1);
2681		if (IS_ERR(handle)) {
2682			ret = PTR_ERR(handle);
2683			goto out_writepages;
2684		}
2685		BUG_ON(ext4_test_inode_state(inode,
2686				EXT4_STATE_MAY_INLINE_DATA));
2687		ext4_destroy_inline_data(handle, inode);
2688		ext4_journal_stop(handle);
2689	}
2690
2691	if (ext4_should_dioread_nolock(inode)) {
2692		/*
2693		 * We may need to convert up to one extent per block in
2694		 * the page and we may dirty the inode.
2695		 */
2696		rsv_blocks = 1 + ext4_chunk_trans_blocks(inode,
2697						PAGE_SIZE >> inode->i_blkbits);
2698	}
2699
2700	if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX)
2701		range_whole = 1;
2702
2703	if (wbc->range_cyclic) {
2704		writeback_index = mapping->writeback_index;
2705		if (writeback_index)
2706			cycled = 0;
2707		mpd.first_page = writeback_index;
2708		mpd.last_page = -1;
2709	} else {
2710		mpd.first_page = wbc->range_start >> PAGE_SHIFT;
2711		mpd.last_page = wbc->range_end >> PAGE_SHIFT;
2712	}
2713
2714	mpd.inode = inode;
2715	mpd.wbc = wbc;
2716	ext4_io_submit_init(&mpd.io_submit, wbc);
2717retry:
2718	if (wbc->sync_mode == WB_SYNC_ALL || wbc->tagged_writepages)
2719		tag_pages_for_writeback(mapping, mpd.first_page, mpd.last_page);
 
2720	blk_start_plug(&plug);
2721
2722	/*
2723	 * First writeback pages that don't need mapping - we can avoid
2724	 * starting a transaction unnecessarily and also avoid being blocked
2725	 * in the block layer on device congestion while having transaction
2726	 * started.
2727	 */
2728	mpd.do_map = 0;
2729	mpd.scanned_until_end = 0;
2730	mpd.io_submit.io_end = ext4_init_io_end(inode, GFP_KERNEL);
2731	if (!mpd.io_submit.io_end) {
2732		ret = -ENOMEM;
2733		goto unplug;
2734	}
2735	ret = mpage_prepare_extent_to_map(&mpd);
2736	/* Unlock pages we didn't use */
2737	mpage_release_unused_pages(&mpd, false);
2738	/* Submit prepared bio */
2739	ext4_io_submit(&mpd.io_submit);
2740	ext4_put_io_end_defer(mpd.io_submit.io_end);
2741	mpd.io_submit.io_end = NULL;
2742	if (ret < 0)
2743		goto unplug;
2744
2745	while (!mpd.scanned_until_end && wbc->nr_to_write > 0) {
2746		/* For each extent of pages we use new io_end */
2747		mpd.io_submit.io_end = ext4_init_io_end(inode, GFP_KERNEL);
2748		if (!mpd.io_submit.io_end) {
2749			ret = -ENOMEM;
2750			break;
2751		}
2752
 
2753		/*
2754		 * We have two constraints: We find one extent to map and we
2755		 * must always write out whole page (makes a difference when
2756		 * blocksize < pagesize) so that we don't block on IO when we
2757		 * try to write out the rest of the page. Journalled mode is
2758		 * not supported by delalloc.
2759		 */
2760		BUG_ON(ext4_should_journal_data(inode));
2761		needed_blocks = ext4_da_writepages_trans_blocks(inode);
2762
2763		/* start a new transaction */
2764		handle = ext4_journal_start_with_reserve(inode,
2765				EXT4_HT_WRITE_PAGE, needed_blocks, rsv_blocks);
2766		if (IS_ERR(handle)) {
2767			ret = PTR_ERR(handle);
2768			ext4_msg(inode->i_sb, KERN_CRIT, "%s: jbd2_start: "
2769			       "%ld pages, ino %lu; err %d", __func__,
2770				wbc->nr_to_write, inode->i_ino, ret);
2771			/* Release allocated io_end */
2772			ext4_put_io_end(mpd.io_submit.io_end);
2773			mpd.io_submit.io_end = NULL;
2774			break;
2775		}
2776		mpd.do_map = 1;
2777
2778		trace_ext4_da_write_pages(inode, mpd.first_page, mpd.wbc);
2779		ret = mpage_prepare_extent_to_map(&mpd);
2780		if (!ret && mpd.map.m_len)
2781			ret = mpage_map_and_submit_extent(handle, &mpd,
2782					&give_up_on_write);
2783		/*
2784		 * Caution: If the handle is synchronous,
2785		 * ext4_journal_stop() can wait for transaction commit
2786		 * to finish which may depend on writeback of pages to
2787		 * complete or on page lock to be released.  In that
2788		 * case, we have to wait until after after we have
2789		 * submitted all the IO, released page locks we hold,
2790		 * and dropped io_end reference (for extent conversion
2791		 * to be able to complete) before stopping the handle.
2792		 */
2793		if (!ext4_handle_valid(handle) || handle->h_sync == 0) {
2794			ext4_journal_stop(handle);
2795			handle = NULL;
2796			mpd.do_map = 0;
2797		}
2798		/* Unlock pages we didn't use */
2799		mpage_release_unused_pages(&mpd, give_up_on_write);
2800		/* Submit prepared bio */
2801		ext4_io_submit(&mpd.io_submit);
2802
2803		/*
2804		 * Drop our io_end reference we got from init. We have
2805		 * to be careful and use deferred io_end finishing if
2806		 * we are still holding the transaction as we can
2807		 * release the last reference to io_end which may end
2808		 * up doing unwritten extent conversion.
2809		 */
2810		if (handle) {
2811			ext4_put_io_end_defer(mpd.io_submit.io_end);
2812			ext4_journal_stop(handle);
2813		} else
2814			ext4_put_io_end(mpd.io_submit.io_end);
2815		mpd.io_submit.io_end = NULL;
2816
2817		if (ret == -ENOSPC && sbi->s_journal) {
2818			/*
2819			 * Commit the transaction which would
2820			 * free blocks released in the transaction
2821			 * and try again
2822			 */
2823			jbd2_journal_force_commit_nested(sbi->s_journal);
2824			ret = 0;
2825			continue;
2826		}
2827		/* Fatal error - ENOMEM, EIO... */
2828		if (ret)
2829			break;
2830	}
2831unplug:
2832	blk_finish_plug(&plug);
2833	if (!ret && !cycled && wbc->nr_to_write > 0) {
2834		cycled = 1;
2835		mpd.last_page = writeback_index - 1;
2836		mpd.first_page = 0;
2837		goto retry;
2838	}
2839
2840	/* Update index */
2841	if (wbc->range_cyclic || (range_whole && wbc->nr_to_write > 0))
2842		/*
2843		 * Set the writeback_index so that range_cyclic
2844		 * mode will write it back later
2845		 */
2846		mapping->writeback_index = mpd.first_page;
2847
2848out_writepages:
2849	trace_ext4_writepages_result(inode, wbc, ret,
2850				     nr_to_write - wbc->nr_to_write);
2851	percpu_up_read(&sbi->s_writepages_rwsem);
2852	return ret;
2853}
2854
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2855static int ext4_dax_writepages(struct address_space *mapping,
2856			       struct writeback_control *wbc)
2857{
2858	int ret;
2859	long nr_to_write = wbc->nr_to_write;
2860	struct inode *inode = mapping->host;
2861	struct ext4_sb_info *sbi = EXT4_SB(mapping->host->i_sb);
2862
2863	if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb))))
2864		return -EIO;
2865
2866	percpu_down_read(&sbi->s_writepages_rwsem);
2867	trace_ext4_writepages(inode, wbc);
2868
2869	ret = dax_writeback_mapping_range(mapping, sbi->s_daxdev, wbc);
2870	trace_ext4_writepages_result(inode, wbc, ret,
2871				     nr_to_write - wbc->nr_to_write);
2872	percpu_up_read(&sbi->s_writepages_rwsem);
2873	return ret;
2874}
2875
2876static int ext4_nonda_switch(struct super_block *sb)
2877{
2878	s64 free_clusters, dirty_clusters;
2879	struct ext4_sb_info *sbi = EXT4_SB(sb);
2880
2881	/*
2882	 * switch to non delalloc mode if we are running low
2883	 * on free block. The free block accounting via percpu
2884	 * counters can get slightly wrong with percpu_counter_batch getting
2885	 * accumulated on each CPU without updating global counters
2886	 * Delalloc need an accurate free block accounting. So switch
2887	 * to non delalloc when we are near to error range.
2888	 */
2889	free_clusters =
2890		percpu_counter_read_positive(&sbi->s_freeclusters_counter);
2891	dirty_clusters =
2892		percpu_counter_read_positive(&sbi->s_dirtyclusters_counter);
2893	/*
2894	 * Start pushing delalloc when 1/2 of free blocks are dirty.
2895	 */
2896	if (dirty_clusters && (free_clusters < 2 * dirty_clusters))
2897		try_to_writeback_inodes_sb(sb, WB_REASON_FS_FREE_SPACE);
2898
2899	if (2 * free_clusters < 3 * dirty_clusters ||
2900	    free_clusters < (dirty_clusters + EXT4_FREECLUSTERS_WATERMARK)) {
2901		/*
2902		 * free block count is less than 150% of dirty blocks
2903		 * or free blocks is less than watermark
2904		 */
2905		return 1;
2906	}
2907	return 0;
2908}
2909
2910/* We always reserve for an inode update; the superblock could be there too */
2911static int ext4_da_write_credits(struct inode *inode, loff_t pos, unsigned len)
2912{
2913	if (likely(ext4_has_feature_large_file(inode->i_sb)))
2914		return 1;
2915
2916	if (pos + len <= 0x7fffffffULL)
2917		return 1;
2918
2919	/* We might need to update the superblock to set LARGE_FILE */
2920	return 2;
2921}
2922
2923static int ext4_da_write_begin(struct file *file, struct address_space *mapping,
2924			       loff_t pos, unsigned len, unsigned flags,
2925			       struct page **pagep, void **fsdata)
2926{
2927	int ret, retries = 0;
2928	struct page *page;
2929	pgoff_t index;
2930	struct inode *inode = mapping->host;
2931	handle_t *handle;
2932
2933	if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb))))
2934		return -EIO;
2935
2936	index = pos >> PAGE_SHIFT;
2937
2938	if (ext4_nonda_switch(inode->i_sb) || S_ISLNK(inode->i_mode) ||
2939	    ext4_verity_in_progress(inode)) {
2940		*fsdata = (void *)FALL_BACK_TO_NONDELALLOC;
2941		return ext4_write_begin(file, mapping, pos,
2942					len, flags, pagep, fsdata);
2943	}
2944	*fsdata = (void *)0;
2945	trace_ext4_da_write_begin(inode, pos, len, flags);
2946
2947	if (ext4_test_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA)) {
2948		ret = ext4_da_write_inline_data_begin(mapping, inode,
2949						      pos, len, flags,
2950						      pagep, fsdata);
2951		if (ret < 0)
2952			return ret;
2953		if (ret == 1)
2954			return 0;
2955	}
2956
2957	/*
2958	 * grab_cache_page_write_begin() can take a long time if the
2959	 * system is thrashing due to memory pressure, or if the page
2960	 * is being written back.  So grab it first before we start
2961	 * the transaction handle.  This also allows us to allocate
2962	 * the page (if needed) without using GFP_NOFS.
2963	 */
2964retry_grab:
2965	page = grab_cache_page_write_begin(mapping, index, flags);
2966	if (!page)
2967		return -ENOMEM;
2968	unlock_page(page);
2969
2970	/*
2971	 * With delayed allocation, we don't log the i_disksize update
2972	 * if there is delayed block allocation. But we still need
2973	 * to journalling the i_disksize update if writes to the end
2974	 * of file which has an already mapped buffer.
2975	 */
2976retry_journal:
2977	handle = ext4_journal_start(inode, EXT4_HT_WRITE_PAGE,
2978				ext4_da_write_credits(inode, pos, len));
2979	if (IS_ERR(handle)) {
2980		put_page(page);
2981		return PTR_ERR(handle);
2982	}
2983
2984	lock_page(page);
2985	if (page->mapping != mapping) {
2986		/* The page got truncated from under us */
2987		unlock_page(page);
2988		put_page(page);
2989		ext4_journal_stop(handle);
2990		goto retry_grab;
2991	}
2992	/* In case writeback began while the page was unlocked */
2993	wait_for_stable_page(page);
2994
2995#ifdef CONFIG_FS_ENCRYPTION
2996	ret = ext4_block_write_begin(page, pos, len,
2997				     ext4_da_get_block_prep);
2998#else
2999	ret = __block_write_begin(page, pos, len, ext4_da_get_block_prep);
3000#endif
3001	if (ret < 0) {
3002		unlock_page(page);
3003		ext4_journal_stop(handle);
3004		/*
3005		 * block_write_begin may have instantiated a few blocks
3006		 * outside i_size.  Trim these off again. Don't need
3007		 * i_size_read because we hold i_mutex.
3008		 */
3009		if (pos + len > inode->i_size)
3010			ext4_truncate_failed_write(inode);
3011
3012		if (ret == -ENOSPC &&
3013		    ext4_should_retry_alloc(inode->i_sb, &retries))
3014			goto retry_journal;
3015
3016		put_page(page);
3017		return ret;
3018	}
3019
3020	*pagep = page;
3021	return ret;
3022}
3023
3024/*
3025 * Check if we should update i_disksize
3026 * when write to the end of file but not require block allocation
3027 */
3028static int ext4_da_should_update_i_disksize(struct page *page,
3029					    unsigned long offset)
3030{
3031	struct buffer_head *bh;
3032	struct inode *inode = page->mapping->host;
3033	unsigned int idx;
3034	int i;
3035
3036	bh = page_buffers(page);
3037	idx = offset >> inode->i_blkbits;
3038
3039	for (i = 0; i < idx; i++)
3040		bh = bh->b_this_page;
3041
3042	if (!buffer_mapped(bh) || (buffer_delay(bh)) || buffer_unwritten(bh))
3043		return 0;
3044	return 1;
3045}
3046
3047static int ext4_da_write_end(struct file *file,
3048			     struct address_space *mapping,
3049			     loff_t pos, unsigned len, unsigned copied,
3050			     struct page *page, void *fsdata)
3051{
3052	struct inode *inode = mapping->host;
3053	int ret = 0, ret2;
3054	handle_t *handle = ext4_journal_current_handle();
3055	loff_t new_i_size;
3056	unsigned long start, end;
3057	int write_mode = (int)(unsigned long)fsdata;
3058
3059	if (write_mode == FALL_BACK_TO_NONDELALLOC)
3060		return ext4_write_end(file, mapping, pos,
3061				      len, copied, page, fsdata);
3062
3063	trace_ext4_da_write_end(inode, pos, len, copied);
 
 
 
 
 
 
3064	start = pos & (PAGE_SIZE - 1);
3065	end = start + copied - 1;
3066
3067	/*
3068	 * generic_write_end() will run mark_inode_dirty() if i_size
3069	 * changes.  So let's piggyback the i_disksize mark_inode_dirty
3070	 * into that.
 
 
 
 
 
 
 
 
 
 
3071	 */
3072	new_i_size = pos + copied;
3073	if (copied && new_i_size > EXT4_I(inode)->i_disksize) {
3074		if (ext4_has_inline_data(inode) ||
3075		    ext4_da_should_update_i_disksize(page, end)) {
3076			ext4_update_i_disksize(inode, new_i_size);
3077			/* We need to mark inode dirty even if
3078			 * new_i_size is less that inode->i_size
3079			 * bu greater than i_disksize.(hint delalloc)
3080			 */
3081			ret = ext4_mark_inode_dirty(handle, inode);
3082		}
3083	}
3084
3085	if (write_mode != CONVERT_INLINE_DATA &&
3086	    ext4_test_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA) &&
3087	    ext4_has_inline_data(inode))
3088		ret2 = ext4_da_write_inline_data_end(inode, pos, len, copied,
3089						     page);
3090	else
3091		ret2 = generic_write_end(file, mapping, pos, len, copied,
3092							page, fsdata);
3093
3094	copied = ret2;
3095	if (ret2 < 0)
3096		ret = ret2;
3097	ret2 = ext4_journal_stop(handle);
3098	if (unlikely(ret2 && !ret))
3099		ret = ret2;
3100
3101	return ret ? ret : copied;
3102}
3103
3104/*
3105 * Force all delayed allocation blocks to be allocated for a given inode.
3106 */
3107int ext4_alloc_da_blocks(struct inode *inode)
3108{
3109	trace_ext4_alloc_da_blocks(inode);
3110
3111	if (!EXT4_I(inode)->i_reserved_data_blocks)
3112		return 0;
3113
3114	/*
3115	 * We do something simple for now.  The filemap_flush() will
3116	 * also start triggering a write of the data blocks, which is
3117	 * not strictly speaking necessary (and for users of
3118	 * laptop_mode, not even desirable).  However, to do otherwise
3119	 * would require replicating code paths in:
3120	 *
3121	 * ext4_writepages() ->
3122	 *    write_cache_pages() ---> (via passed in callback function)
3123	 *        __mpage_da_writepage() -->
3124	 *           mpage_add_bh_to_extent()
3125	 *           mpage_da_map_blocks()
3126	 *
3127	 * The problem is that write_cache_pages(), located in
3128	 * mm/page-writeback.c, marks pages clean in preparation for
3129	 * doing I/O, which is not desirable if we're not planning on
3130	 * doing I/O at all.
3131	 *
3132	 * We could call write_cache_pages(), and then redirty all of
3133	 * the pages by calling redirty_page_for_writepage() but that
3134	 * would be ugly in the extreme.  So instead we would need to
3135	 * replicate parts of the code in the above functions,
3136	 * simplifying them because we wouldn't actually intend to
3137	 * write out the pages, but rather only collect contiguous
3138	 * logical block extents, call the multi-block allocator, and
3139	 * then update the buffer heads with the block allocations.
3140	 *
3141	 * For now, though, we'll cheat by calling filemap_flush(),
3142	 * which will map the blocks, and start the I/O, but not
3143	 * actually wait for the I/O to complete.
3144	 */
3145	return filemap_flush(inode->i_mapping);
3146}
3147
3148/*
3149 * bmap() is special.  It gets used by applications such as lilo and by
3150 * the swapper to find the on-disk block of a specific piece of data.
3151 *
3152 * Naturally, this is dangerous if the block concerned is still in the
3153 * journal.  If somebody makes a swapfile on an ext4 data-journaling
3154 * filesystem and enables swap, then they may get a nasty shock when the
3155 * data getting swapped to that swapfile suddenly gets overwritten by
3156 * the original zero's written out previously to the journal and
3157 * awaiting writeback in the kernel's buffer cache.
3158 *
3159 * So, if we see any bmap calls here on a modified, data-journaled file,
3160 * take extra steps to flush any blocks which might be in the cache.
3161 */
3162static sector_t ext4_bmap(struct address_space *mapping, sector_t block)
3163{
3164	struct inode *inode = mapping->host;
3165	journal_t *journal;
 
3166	int err;
3167
 
3168	/*
3169	 * We can get here for an inline file via the FIBMAP ioctl
3170	 */
3171	if (ext4_has_inline_data(inode))
3172		return 0;
3173
3174	if (mapping_tagged(mapping, PAGECACHE_TAG_DIRTY) &&
3175			test_opt(inode->i_sb, DELALLOC)) {
3176		/*
3177		 * With delalloc we want to sync the file
3178		 * so that we can make sure we allocate
3179		 * blocks for file
3180		 */
3181		filemap_write_and_wait(mapping);
3182	}
3183
3184	if (EXT4_JOURNAL(inode) &&
3185	    ext4_test_inode_state(inode, EXT4_STATE_JDATA)) {
3186		/*
3187		 * This is a REALLY heavyweight approach, but the use of
3188		 * bmap on dirty files is expected to be extremely rare:
3189		 * only if we run lilo or swapon on a freshly made file
3190		 * do we expect this to happen.
3191		 *
3192		 * (bmap requires CAP_SYS_RAWIO so this does not
3193		 * represent an unprivileged user DOS attack --- we'd be
3194		 * in trouble if mortal users could trigger this path at
3195		 * will.)
3196		 *
3197		 * NB. EXT4_STATE_JDATA is not set on files other than
3198		 * regular files.  If somebody wants to bmap a directory
3199		 * or symlink and gets confused because the buffer
3200		 * hasn't yet been flushed to disk, they deserve
3201		 * everything they get.
3202		 */
3203
3204		ext4_clear_inode_state(inode, EXT4_STATE_JDATA);
3205		journal = EXT4_JOURNAL(inode);
3206		jbd2_journal_lock_updates(journal);
3207		err = jbd2_journal_flush(journal);
3208		jbd2_journal_unlock_updates(journal);
3209
3210		if (err)
3211			return 0;
3212	}
3213
3214	return iomap_bmap(mapping, block, &ext4_iomap_ops);
 
 
 
 
3215}
3216
3217static int ext4_readpage(struct file *file, struct page *page)
3218{
 
3219	int ret = -EAGAIN;
3220	struct inode *inode = page->mapping->host;
3221
3222	trace_ext4_readpage(page);
3223
3224	if (ext4_has_inline_data(inode))
3225		ret = ext4_readpage_inline(inode, page);
3226
3227	if (ret == -EAGAIN)
3228		return ext4_mpage_readpages(inode, NULL, page);
3229
3230	return ret;
3231}
3232
3233static void ext4_readahead(struct readahead_control *rac)
3234{
3235	struct inode *inode = rac->mapping->host;
3236
3237	/* If the file has inline data, no need to do readahead. */
3238	if (ext4_has_inline_data(inode))
3239		return;
3240
3241	ext4_mpage_readpages(inode, rac, NULL);
3242}
3243
3244static void ext4_invalidatepage(struct page *page, unsigned int offset,
3245				unsigned int length)
3246{
3247	trace_ext4_invalidatepage(page, offset, length);
3248
3249	/* No journalling happens on data buffers when this function is used */
3250	WARN_ON(page_has_buffers(page) && buffer_jbd(page_buffers(page)));
3251
3252	block_invalidatepage(page, offset, length);
3253}
3254
3255static int __ext4_journalled_invalidatepage(struct page *page,
3256					    unsigned int offset,
3257					    unsigned int length)
3258{
3259	journal_t *journal = EXT4_JOURNAL(page->mapping->host);
3260
3261	trace_ext4_journalled_invalidatepage(page, offset, length);
3262
3263	/*
3264	 * If it's a full truncate we just forget about the pending dirtying
3265	 */
3266	if (offset == 0 && length == PAGE_SIZE)
3267		ClearPageChecked(page);
3268
3269	return jbd2_journal_invalidatepage(journal, page, offset, length);
3270}
3271
3272/* Wrapper for aops... */
3273static void ext4_journalled_invalidatepage(struct page *page,
3274					   unsigned int offset,
3275					   unsigned int length)
3276{
3277	WARN_ON(__ext4_journalled_invalidatepage(page, offset, length) < 0);
3278}
3279
3280static int ext4_releasepage(struct page *page, gfp_t wait)
3281{
3282	journal_t *journal = EXT4_JOURNAL(page->mapping->host);
3283
3284	trace_ext4_releasepage(page);
3285
3286	/* Page has dirty journalled data -> cannot release */
3287	if (PageChecked(page))
3288		return 0;
3289	if (journal)
3290		return jbd2_journal_try_to_free_buffers(journal, page);
3291	else
3292		return try_to_free_buffers(page);
3293}
3294
3295static bool ext4_inode_datasync_dirty(struct inode *inode)
3296{
3297	journal_t *journal = EXT4_SB(inode->i_sb)->s_journal;
3298
3299	if (journal)
3300		return !jbd2_transaction_committed(journal,
3301					EXT4_I(inode)->i_datasync_tid);
 
 
 
 
 
 
3302	/* Any metadata buffers to write? */
3303	if (!list_empty(&inode->i_mapping->private_list))
3304		return true;
3305	return inode->i_state & I_DIRTY_DATASYNC;
3306}
3307
3308static void ext4_set_iomap(struct inode *inode, struct iomap *iomap,
3309			   struct ext4_map_blocks *map, loff_t offset,
3310			   loff_t length)
3311{
3312	u8 blkbits = inode->i_blkbits;
3313
3314	/*
3315	 * Writes that span EOF might trigger an I/O size update on completion,
3316	 * so consider them to be dirty for the purpose of O_DSYNC, even if
3317	 * there is no other metadata changes being made or are pending.
3318	 */
3319	iomap->flags = 0;
3320	if (ext4_inode_datasync_dirty(inode) ||
3321	    offset + length > i_size_read(inode))
3322		iomap->flags |= IOMAP_F_DIRTY;
3323
3324	if (map->m_flags & EXT4_MAP_NEW)
3325		iomap->flags |= IOMAP_F_NEW;
3326
3327	iomap->bdev = inode->i_sb->s_bdev;
3328	iomap->dax_dev = EXT4_SB(inode->i_sb)->s_daxdev;
 
 
3329	iomap->offset = (u64) map->m_lblk << blkbits;
3330	iomap->length = (u64) map->m_len << blkbits;
3331
3332	if ((map->m_flags & EXT4_MAP_MAPPED) &&
3333	    !ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
3334		iomap->flags |= IOMAP_F_MERGED;
3335
3336	/*
3337	 * Flags passed to ext4_map_blocks() for direct I/O writes can result
3338	 * in m_flags having both EXT4_MAP_MAPPED and EXT4_MAP_UNWRITTEN bits
3339	 * set. In order for any allocated unwritten extents to be converted
3340	 * into written extents correctly within the ->end_io() handler, we
3341	 * need to ensure that the iomap->type is set appropriately. Hence, the
3342	 * reason why we need to check whether the EXT4_MAP_UNWRITTEN bit has
3343	 * been set first.
3344	 */
3345	if (map->m_flags & EXT4_MAP_UNWRITTEN) {
3346		iomap->type = IOMAP_UNWRITTEN;
3347		iomap->addr = (u64) map->m_pblk << blkbits;
 
 
3348	} else if (map->m_flags & EXT4_MAP_MAPPED) {
3349		iomap->type = IOMAP_MAPPED;
3350		iomap->addr = (u64) map->m_pblk << blkbits;
 
 
3351	} else {
3352		iomap->type = IOMAP_HOLE;
3353		iomap->addr = IOMAP_NULL_ADDR;
3354	}
3355}
3356
3357static int ext4_iomap_alloc(struct inode *inode, struct ext4_map_blocks *map,
3358			    unsigned int flags)
3359{
3360	handle_t *handle;
3361	u8 blkbits = inode->i_blkbits;
3362	int ret, dio_credits, m_flags = 0, retries = 0;
3363
3364	/*
3365	 * Trim the mapping request to the maximum value that we can map at
3366	 * once for direct I/O.
3367	 */
3368	if (map->m_len > DIO_MAX_BLOCKS)
3369		map->m_len = DIO_MAX_BLOCKS;
3370	dio_credits = ext4_chunk_trans_blocks(inode, map->m_len);
3371
3372retry:
3373	/*
3374	 * Either we allocate blocks and then don't get an unwritten extent, so
3375	 * in that case we have reserved enough credits. Or, the blocks are
3376	 * already allocated and unwritten. In that case, the extent conversion
3377	 * fits into the credits as well.
3378	 */
3379	handle = ext4_journal_start(inode, EXT4_HT_MAP_BLOCKS, dio_credits);
3380	if (IS_ERR(handle))
3381		return PTR_ERR(handle);
3382
3383	/*
3384	 * DAX and direct I/O are the only two operations that are currently
3385	 * supported with IOMAP_WRITE.
3386	 */
3387	WARN_ON(!IS_DAX(inode) && !(flags & IOMAP_DIRECT));
3388	if (IS_DAX(inode))
3389		m_flags = EXT4_GET_BLOCKS_CREATE_ZERO;
3390	/*
3391	 * We use i_size instead of i_disksize here because delalloc writeback
3392	 * can complete at any point during the I/O and subsequently push the
3393	 * i_disksize out to i_size. This could be beyond where direct I/O is
3394	 * happening and thus expose allocated blocks to direct I/O reads.
3395	 */
3396	else if ((map->m_lblk * (1 << blkbits)) >= i_size_read(inode))
3397		m_flags = EXT4_GET_BLOCKS_CREATE;
3398	else if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
3399		m_flags = EXT4_GET_BLOCKS_IO_CREATE_EXT;
3400
3401	ret = ext4_map_blocks(handle, inode, map, m_flags);
3402
3403	/*
3404	 * We cannot fill holes in indirect tree based inodes as that could
3405	 * expose stale data in the case of a crash. Use the magic error code
3406	 * to fallback to buffered I/O.
3407	 */
3408	if (!m_flags && !ret)
3409		ret = -ENOTBLK;
3410
3411	ext4_journal_stop(handle);
3412	if (ret == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
3413		goto retry;
3414
3415	return ret;
3416}
3417
3418
3419static int ext4_iomap_begin(struct inode *inode, loff_t offset, loff_t length,
3420		unsigned flags, struct iomap *iomap, struct iomap *srcmap)
3421{
3422	int ret;
3423	struct ext4_map_blocks map;
3424	u8 blkbits = inode->i_blkbits;
3425
3426	if ((offset >> blkbits) > EXT4_MAX_LOGICAL_BLOCK)
3427		return -EINVAL;
3428
3429	if (WARN_ON_ONCE(ext4_has_inline_data(inode)))
3430		return -ERANGE;
3431
3432	/*
3433	 * Calculate the first and last logical blocks respectively.
3434	 */
3435	map.m_lblk = offset >> blkbits;
3436	map.m_len = min_t(loff_t, (offset + length - 1) >> blkbits,
3437			  EXT4_MAX_LOGICAL_BLOCK) - map.m_lblk + 1;
3438
3439	if (flags & IOMAP_WRITE)
 
 
 
 
 
 
 
 
 
 
 
3440		ret = ext4_iomap_alloc(inode, &map, flags);
3441	else
3442		ret = ext4_map_blocks(NULL, inode, &map, 0);
 
3443
3444	if (ret < 0)
3445		return ret;
 
 
 
 
 
 
 
3446
3447	ext4_set_iomap(inode, iomap, &map, offset, length);
3448
3449	return 0;
3450}
3451
3452static int ext4_iomap_overwrite_begin(struct inode *inode, loff_t offset,
3453		loff_t length, unsigned flags, struct iomap *iomap,
3454		struct iomap *srcmap)
3455{
3456	int ret;
3457
3458	/*
3459	 * Even for writes we don't need to allocate blocks, so just pretend
3460	 * we are reading to save overhead of starting a transaction.
3461	 */
3462	flags &= ~IOMAP_WRITE;
3463	ret = ext4_iomap_begin(inode, offset, length, flags, iomap, srcmap);
3464	WARN_ON_ONCE(iomap->type != IOMAP_MAPPED);
3465	return ret;
3466}
3467
3468static int ext4_iomap_end(struct inode *inode, loff_t offset, loff_t length,
3469			  ssize_t written, unsigned flags, struct iomap *iomap)
3470{
3471	/*
3472	 * Check to see whether an error occurred while writing out the data to
3473	 * the allocated blocks. If so, return the magic error code so that we
3474	 * fallback to buffered I/O and attempt to complete the remainder of
3475	 * the I/O. Any blocks that may have been allocated in preparation for
3476	 * the direct I/O will be reused during buffered I/O.
3477	 */
3478	if (flags & (IOMAP_WRITE | IOMAP_DIRECT) && written == 0)
3479		return -ENOTBLK;
3480
3481	return 0;
3482}
3483
3484const struct iomap_ops ext4_iomap_ops = {
3485	.iomap_begin		= ext4_iomap_begin,
3486	.iomap_end		= ext4_iomap_end,
3487};
3488
3489const struct iomap_ops ext4_iomap_overwrite_ops = {
3490	.iomap_begin		= ext4_iomap_overwrite_begin,
3491	.iomap_end		= ext4_iomap_end,
3492};
3493
3494static bool ext4_iomap_is_delalloc(struct inode *inode,
3495				   struct ext4_map_blocks *map)
3496{
3497	struct extent_status es;
3498	ext4_lblk_t offset = 0, end = map->m_lblk + map->m_len - 1;
3499
3500	ext4_es_find_extent_range(inode, &ext4_es_is_delayed,
3501				  map->m_lblk, end, &es);
3502
3503	if (!es.es_len || es.es_lblk > end)
3504		return false;
3505
3506	if (es.es_lblk > map->m_lblk) {
3507		map->m_len = es.es_lblk - map->m_lblk;
3508		return false;
3509	}
3510
3511	offset = map->m_lblk - es.es_lblk;
3512	map->m_len = es.es_len - offset;
3513
3514	return true;
3515}
3516
3517static int ext4_iomap_begin_report(struct inode *inode, loff_t offset,
3518				   loff_t length, unsigned int flags,
3519				   struct iomap *iomap, struct iomap *srcmap)
3520{
3521	int ret;
3522	bool delalloc = false;
3523	struct ext4_map_blocks map;
3524	u8 blkbits = inode->i_blkbits;
3525
3526	if ((offset >> blkbits) > EXT4_MAX_LOGICAL_BLOCK)
3527		return -EINVAL;
3528
3529	if (ext4_has_inline_data(inode)) {
3530		ret = ext4_inline_data_iomap(inode, iomap);
3531		if (ret != -EAGAIN) {
3532			if (ret == 0 && offset >= iomap->length)
3533				ret = -ENOENT;
3534			return ret;
3535		}
3536	}
3537
3538	/*
3539	 * Calculate the first and last logical block respectively.
3540	 */
3541	map.m_lblk = offset >> blkbits;
3542	map.m_len = min_t(loff_t, (offset + length - 1) >> blkbits,
3543			  EXT4_MAX_LOGICAL_BLOCK) - map.m_lblk + 1;
3544
3545	/*
3546	 * Fiemap callers may call for offset beyond s_bitmap_maxbytes.
3547	 * So handle it here itself instead of querying ext4_map_blocks().
3548	 * Since ext4_map_blocks() will warn about it and will return
3549	 * -EIO error.
3550	 */
3551	if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) {
3552		struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
3553
3554		if (offset >= sbi->s_bitmap_maxbytes) {
3555			map.m_flags = 0;
3556			goto set_iomap;
3557		}
3558	}
3559
3560	ret = ext4_map_blocks(NULL, inode, &map, 0);
3561	if (ret < 0)
3562		return ret;
3563	if (ret == 0)
3564		delalloc = ext4_iomap_is_delalloc(inode, &map);
3565
3566set_iomap:
3567	ext4_set_iomap(inode, iomap, &map, offset, length);
3568	if (delalloc && iomap->type == IOMAP_HOLE)
3569		iomap->type = IOMAP_DELALLOC;
3570
3571	return 0;
3572}
3573
3574const struct iomap_ops ext4_iomap_report_ops = {
3575	.iomap_begin = ext4_iomap_begin_report,
3576};
3577
3578/*
3579 * Pages can be marked dirty completely asynchronously from ext4's journalling
3580 * activity.  By filemap_sync_pte(), try_to_unmap_one(), etc.  We cannot do
3581 * much here because ->set_page_dirty is called under VFS locks.  The page is
3582 * not necessarily locked.
 
3583 *
3584 * We cannot just dirty the page and leave attached buffers clean, because the
3585 * buffers' dirty state is "definitive".  We cannot just set the buffers dirty
3586 * or jbddirty because all the journalling code will explode.
3587 *
3588 * So what we do is to mark the page "pending dirty" and next time writepage
3589 * is called, propagate that into the buffers appropriately.
3590 */
3591static int ext4_journalled_set_page_dirty(struct page *page)
 
 
 
 
 
 
 
 
3592{
3593	SetPageChecked(page);
3594	return __set_page_dirty_nobuffers(page);
 
3595}
3596
3597static int ext4_set_page_dirty(struct page *page)
 
3598{
3599	WARN_ON_ONCE(!PageLocked(page) && !PageDirty(page));
3600	WARN_ON_ONCE(!page_has_buffers(page));
3601	return __set_page_dirty_buffers(page);
3602}
3603
3604static const struct address_space_operations ext4_aops = {
3605	.readpage		= ext4_readpage,
3606	.readahead		= ext4_readahead,
3607	.writepage		= ext4_writepage,
3608	.writepages		= ext4_writepages,
3609	.write_begin		= ext4_write_begin,
3610	.write_end		= ext4_write_end,
3611	.set_page_dirty		= ext4_set_page_dirty,
3612	.bmap			= ext4_bmap,
3613	.invalidatepage		= ext4_invalidatepage,
3614	.releasepage		= ext4_releasepage,
3615	.direct_IO		= noop_direct_IO,
3616	.migratepage		= buffer_migrate_page,
3617	.is_partially_uptodate  = block_is_partially_uptodate,
3618	.error_remove_page	= generic_error_remove_page,
 
3619};
3620
3621static const struct address_space_operations ext4_journalled_aops = {
3622	.readpage		= ext4_readpage,
3623	.readahead		= ext4_readahead,
3624	.writepage		= ext4_writepage,
3625	.writepages		= ext4_writepages,
3626	.write_begin		= ext4_write_begin,
3627	.write_end		= ext4_journalled_write_end,
3628	.set_page_dirty		= ext4_journalled_set_page_dirty,
3629	.bmap			= ext4_bmap,
3630	.invalidatepage		= ext4_journalled_invalidatepage,
3631	.releasepage		= ext4_releasepage,
3632	.direct_IO		= noop_direct_IO,
 
3633	.is_partially_uptodate  = block_is_partially_uptodate,
3634	.error_remove_page	= generic_error_remove_page,
 
3635};
3636
3637static const struct address_space_operations ext4_da_aops = {
3638	.readpage		= ext4_readpage,
3639	.readahead		= ext4_readahead,
3640	.writepage		= ext4_writepage,
3641	.writepages		= ext4_writepages,
3642	.write_begin		= ext4_da_write_begin,
3643	.write_end		= ext4_da_write_end,
3644	.set_page_dirty		= ext4_set_page_dirty,
3645	.bmap			= ext4_bmap,
3646	.invalidatepage		= ext4_invalidatepage,
3647	.releasepage		= ext4_releasepage,
3648	.direct_IO		= noop_direct_IO,
3649	.migratepage		= buffer_migrate_page,
3650	.is_partially_uptodate  = block_is_partially_uptodate,
3651	.error_remove_page	= generic_error_remove_page,
 
3652};
3653
3654static const struct address_space_operations ext4_dax_aops = {
3655	.writepages		= ext4_dax_writepages,
3656	.direct_IO		= noop_direct_IO,
3657	.set_page_dirty		= noop_set_page_dirty,
3658	.bmap			= ext4_bmap,
3659	.invalidatepage		= noop_invalidatepage,
3660};
3661
3662void ext4_set_aops(struct inode *inode)
3663{
3664	switch (ext4_inode_journal_mode(inode)) {
3665	case EXT4_INODE_ORDERED_DATA_MODE:
3666	case EXT4_INODE_WRITEBACK_DATA_MODE:
3667		break;
3668	case EXT4_INODE_JOURNAL_DATA_MODE:
3669		inode->i_mapping->a_ops = &ext4_journalled_aops;
3670		return;
3671	default:
3672		BUG();
3673	}
3674	if (IS_DAX(inode))
3675		inode->i_mapping->a_ops = &ext4_dax_aops;
3676	else if (test_opt(inode->i_sb, DELALLOC))
3677		inode->i_mapping->a_ops = &ext4_da_aops;
3678	else
3679		inode->i_mapping->a_ops = &ext4_aops;
3680}
3681
3682static int __ext4_block_zero_page_range(handle_t *handle,
3683		struct address_space *mapping, loff_t from, loff_t length)
3684{
3685	ext4_fsblk_t index = from >> PAGE_SHIFT;
3686	unsigned offset = from & (PAGE_SIZE-1);
3687	unsigned blocksize, pos;
3688	ext4_lblk_t iblock;
3689	struct inode *inode = mapping->host;
3690	struct buffer_head *bh;
3691	struct page *page;
3692	int err = 0;
3693
3694	page = find_or_create_page(mapping, from >> PAGE_SHIFT,
3695				   mapping_gfp_constraint(mapping, ~__GFP_FS));
3696	if (!page)
3697		return -ENOMEM;
3698
3699	blocksize = inode->i_sb->s_blocksize;
3700
3701	iblock = index << (PAGE_SHIFT - inode->i_sb->s_blocksize_bits);
3702
3703	if (!page_has_buffers(page))
3704		create_empty_buffers(page, blocksize, 0);
3705
3706	/* Find the buffer that contains "offset" */
3707	bh = page_buffers(page);
3708	pos = blocksize;
3709	while (offset >= pos) {
3710		bh = bh->b_this_page;
3711		iblock++;
3712		pos += blocksize;
3713	}
3714	if (buffer_freed(bh)) {
3715		BUFFER_TRACE(bh, "freed: skip");
3716		goto unlock;
3717	}
3718	if (!buffer_mapped(bh)) {
3719		BUFFER_TRACE(bh, "unmapped");
3720		ext4_get_block(inode, iblock, bh, 0);
3721		/* unmapped? It's a hole - nothing to do */
3722		if (!buffer_mapped(bh)) {
3723			BUFFER_TRACE(bh, "still unmapped");
3724			goto unlock;
3725		}
3726	}
3727
3728	/* Ok, it's mapped. Make sure it's up-to-date */
3729	if (PageUptodate(page))
3730		set_buffer_uptodate(bh);
3731
3732	if (!buffer_uptodate(bh)) {
3733		err = -EIO;
3734		ll_rw_block(REQ_OP_READ, 0, 1, &bh);
3735		wait_on_buffer(bh);
3736		/* Uhhuh. Read error. Complain and punt. */
3737		if (!buffer_uptodate(bh))
3738			goto unlock;
3739		if (fscrypt_inode_uses_fs_layer_crypto(inode)) {
3740			/* We expect the key to be set. */
3741			BUG_ON(!fscrypt_has_encryption_key(inode));
3742			err = fscrypt_decrypt_pagecache_blocks(page, blocksize,
3743							       bh_offset(bh));
3744			if (err) {
3745				clear_buffer_uptodate(bh);
3746				goto unlock;
3747			}
3748		}
3749	}
3750	if (ext4_should_journal_data(inode)) {
3751		BUFFER_TRACE(bh, "get write access");
3752		err = ext4_journal_get_write_access(handle, bh);
 
3753		if (err)
3754			goto unlock;
3755	}
3756	zero_user(page, offset, length);
3757	BUFFER_TRACE(bh, "zeroed end of block");
3758
3759	if (ext4_should_journal_data(inode)) {
3760		err = ext4_handle_dirty_metadata(handle, inode, bh);
3761	} else {
3762		err = 0;
3763		mark_buffer_dirty(bh);
3764		if (ext4_should_order_data(inode))
3765			err = ext4_jbd2_inode_add_write(handle, inode, from,
3766					length);
3767	}
3768
3769unlock:
3770	unlock_page(page);
3771	put_page(page);
3772	return err;
3773}
3774
3775/*
3776 * ext4_block_zero_page_range() zeros out a mapping of length 'length'
3777 * starting from file offset 'from'.  The range to be zero'd must
3778 * be contained with in one block.  If the specified range exceeds
3779 * the end of the block it will be shortened to end of the block
3780 * that cooresponds to 'from'
3781 */
3782static int ext4_block_zero_page_range(handle_t *handle,
3783		struct address_space *mapping, loff_t from, loff_t length)
3784{
3785	struct inode *inode = mapping->host;
3786	unsigned offset = from & (PAGE_SIZE-1);
3787	unsigned blocksize = inode->i_sb->s_blocksize;
3788	unsigned max = blocksize - (offset & (blocksize - 1));
3789
3790	/*
3791	 * correct length if it does not fall between
3792	 * 'from' and the end of the block
3793	 */
3794	if (length > max || length < 0)
3795		length = max;
3796
3797	if (IS_DAX(inode)) {
3798		return iomap_zero_range(inode, from, length, NULL,
3799					&ext4_iomap_ops);
3800	}
3801	return __ext4_block_zero_page_range(handle, mapping, from, length);
3802}
3803
3804/*
3805 * ext4_block_truncate_page() zeroes out a mapping from file offset `from'
3806 * up to the end of the block which corresponds to `from'.
3807 * This required during truncate. We need to physically zero the tail end
3808 * of that block so it doesn't yield old data if the file is later grown.
3809 */
3810static int ext4_block_truncate_page(handle_t *handle,
3811		struct address_space *mapping, loff_t from)
3812{
3813	unsigned offset = from & (PAGE_SIZE-1);
3814	unsigned length;
3815	unsigned blocksize;
3816	struct inode *inode = mapping->host;
3817
3818	/* If we are processing an encrypted inode during orphan list handling */
3819	if (IS_ENCRYPTED(inode) && !fscrypt_has_encryption_key(inode))
3820		return 0;
3821
3822	blocksize = inode->i_sb->s_blocksize;
3823	length = blocksize - (offset & (blocksize - 1));
3824
3825	return ext4_block_zero_page_range(handle, mapping, from, length);
3826}
3827
3828int ext4_zero_partial_blocks(handle_t *handle, struct inode *inode,
3829			     loff_t lstart, loff_t length)
3830{
3831	struct super_block *sb = inode->i_sb;
3832	struct address_space *mapping = inode->i_mapping;
3833	unsigned partial_start, partial_end;
3834	ext4_fsblk_t start, end;
3835	loff_t byte_end = (lstart + length - 1);
3836	int err = 0;
3837
3838	partial_start = lstart & (sb->s_blocksize - 1);
3839	partial_end = byte_end & (sb->s_blocksize - 1);
3840
3841	start = lstart >> sb->s_blocksize_bits;
3842	end = byte_end >> sb->s_blocksize_bits;
3843
3844	/* Handle partial zero within the single block */
3845	if (start == end &&
3846	    (partial_start || (partial_end != sb->s_blocksize - 1))) {
3847		err = ext4_block_zero_page_range(handle, mapping,
3848						 lstart, length);
3849		return err;
3850	}
3851	/* Handle partial zero out on the start of the range */
3852	if (partial_start) {
3853		err = ext4_block_zero_page_range(handle, mapping,
3854						 lstart, sb->s_blocksize);
3855		if (err)
3856			return err;
3857	}
3858	/* Handle partial zero out on the end of the range */
3859	if (partial_end != sb->s_blocksize - 1)
3860		err = ext4_block_zero_page_range(handle, mapping,
3861						 byte_end - partial_end,
3862						 partial_end + 1);
3863	return err;
3864}
3865
3866int ext4_can_truncate(struct inode *inode)
3867{
3868	if (S_ISREG(inode->i_mode))
3869		return 1;
3870	if (S_ISDIR(inode->i_mode))
3871		return 1;
3872	if (S_ISLNK(inode->i_mode))
3873		return !ext4_inode_is_fast_symlink(inode);
3874	return 0;
3875}
3876
3877/*
3878 * We have to make sure i_disksize gets properly updated before we truncate
3879 * page cache due to hole punching or zero range. Otherwise i_disksize update
3880 * can get lost as it may have been postponed to submission of writeback but
3881 * that will never happen after we truncate page cache.
3882 */
3883int ext4_update_disksize_before_punch(struct inode *inode, loff_t offset,
3884				      loff_t len)
3885{
3886	handle_t *handle;
3887	int ret;
3888
3889	loff_t size = i_size_read(inode);
3890
3891	WARN_ON(!inode_is_locked(inode));
3892	if (offset > size || offset + len < size)
3893		return 0;
3894
3895	if (EXT4_I(inode)->i_disksize >= size)
3896		return 0;
3897
3898	handle = ext4_journal_start(inode, EXT4_HT_MISC, 1);
3899	if (IS_ERR(handle))
3900		return PTR_ERR(handle);
3901	ext4_update_i_disksize(inode, size);
3902	ret = ext4_mark_inode_dirty(handle, inode);
3903	ext4_journal_stop(handle);
3904
3905	return ret;
3906}
3907
3908static void ext4_wait_dax_page(struct ext4_inode_info *ei)
3909{
3910	up_write(&ei->i_mmap_sem);
3911	schedule();
3912	down_write(&ei->i_mmap_sem);
3913}
3914
3915int ext4_break_layouts(struct inode *inode)
3916{
3917	struct ext4_inode_info *ei = EXT4_I(inode);
3918	struct page *page;
3919	int error;
3920
3921	if (WARN_ON_ONCE(!rwsem_is_locked(&ei->i_mmap_sem)))
3922		return -EINVAL;
3923
3924	do {
3925		page = dax_layout_busy_page(inode->i_mapping);
3926		if (!page)
3927			return 0;
3928
3929		error = ___wait_var_event(&page->_refcount,
3930				atomic_read(&page->_refcount) == 1,
3931				TASK_INTERRUPTIBLE, 0, 0,
3932				ext4_wait_dax_page(ei));
3933	} while (error == 0);
3934
3935	return error;
3936}
3937
3938/*
3939 * ext4_punch_hole: punches a hole in a file by releasing the blocks
3940 * associated with the given offset and length
3941 *
3942 * @inode:  File inode
3943 * @offset: The offset where the hole will begin
3944 * @len:    The length of the hole
3945 *
3946 * Returns: 0 on success or negative on failure
3947 */
3948
3949int ext4_punch_hole(struct inode *inode, loff_t offset, loff_t length)
3950{
 
3951	struct super_block *sb = inode->i_sb;
3952	ext4_lblk_t first_block, stop_block;
3953	struct address_space *mapping = inode->i_mapping;
3954	loff_t first_block_offset, last_block_offset;
 
3955	handle_t *handle;
3956	unsigned int credits;
3957	int ret = 0, ret2 = 0;
3958
3959	trace_ext4_punch_hole(inode, offset, length, 0);
3960
3961	ext4_clear_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA);
3962	if (ext4_has_inline_data(inode)) {
3963		down_write(&EXT4_I(inode)->i_mmap_sem);
3964		ret = ext4_convert_inline_data(inode);
3965		up_write(&EXT4_I(inode)->i_mmap_sem);
3966		if (ret)
3967			return ret;
3968	}
3969
3970	/*
3971	 * Write out all dirty pages to avoid race conditions
3972	 * Then release them.
3973	 */
3974	if (mapping_tagged(mapping, PAGECACHE_TAG_DIRTY)) {
3975		ret = filemap_write_and_wait_range(mapping, offset,
3976						   offset + length - 1);
3977		if (ret)
3978			return ret;
3979	}
3980
3981	inode_lock(inode);
3982
3983	/* No need to punch hole beyond i_size */
3984	if (offset >= inode->i_size)
3985		goto out_mutex;
3986
3987	/*
3988	 * If the hole extends beyond i_size, set the hole
3989	 * to end after the page that contains i_size
3990	 */
3991	if (offset + length > inode->i_size) {
3992		length = inode->i_size +
3993		   PAGE_SIZE - (inode->i_size & (PAGE_SIZE - 1)) -
3994		   offset;
3995	}
3996
 
 
 
 
 
 
 
 
3997	if (offset & (sb->s_blocksize - 1) ||
3998	    (offset + length) & (sb->s_blocksize - 1)) {
3999		/*
4000		 * Attach jinode to inode for jbd2 if we do any zeroing of
4001		 * partial block
4002		 */
4003		ret = ext4_inode_attach_jinode(inode);
4004		if (ret < 0)
4005			goto out_mutex;
4006
4007	}
4008
4009	/* Wait all existing dio workers, newcomers will block on i_mutex */
4010	inode_dio_wait(inode);
4011
 
 
 
 
4012	/*
4013	 * Prevent page faults from reinstantiating pages we have released from
4014	 * page cache.
4015	 */
4016	down_write(&EXT4_I(inode)->i_mmap_sem);
4017
4018	ret = ext4_break_layouts(inode);
4019	if (ret)
4020		goto out_dio;
4021
4022	first_block_offset = round_up(offset, sb->s_blocksize);
4023	last_block_offset = round_down((offset + length), sb->s_blocksize) - 1;
4024
4025	/* Now release the pages and zero block aligned part of pages*/
4026	if (last_block_offset > first_block_offset) {
4027		ret = ext4_update_disksize_before_punch(inode, offset, length);
4028		if (ret)
4029			goto out_dio;
4030		truncate_pagecache_range(inode, first_block_offset,
4031					 last_block_offset);
4032	}
4033
4034	if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
4035		credits = ext4_writepage_trans_blocks(inode);
4036	else
4037		credits = ext4_blocks_for_truncate(inode);
4038	handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE, credits);
4039	if (IS_ERR(handle)) {
4040		ret = PTR_ERR(handle);
4041		ext4_std_error(sb, ret);
4042		goto out_dio;
4043	}
4044
4045	ret = ext4_zero_partial_blocks(handle, inode, offset,
4046				       length);
4047	if (ret)
4048		goto out_stop;
4049
4050	first_block = (offset + sb->s_blocksize - 1) >>
4051		EXT4_BLOCK_SIZE_BITS(sb);
4052	stop_block = (offset + length) >> EXT4_BLOCK_SIZE_BITS(sb);
4053
4054	/* If there are blocks to remove, do it */
4055	if (stop_block > first_block) {
4056
4057		down_write(&EXT4_I(inode)->i_data_sem);
4058		ext4_discard_preallocations(inode, 0);
4059
4060		ret = ext4_es_remove_extent(inode, first_block,
4061					    stop_block - first_block);
4062		if (ret) {
4063			up_write(&EXT4_I(inode)->i_data_sem);
4064			goto out_stop;
4065		}
4066
4067		if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
4068			ret = ext4_ext_remove_space(inode, first_block,
4069						    stop_block - 1);
4070		else
4071			ret = ext4_ind_remove_space(handle, inode, first_block,
4072						    stop_block);
4073
4074		up_write(&EXT4_I(inode)->i_data_sem);
4075	}
 
4076	if (IS_SYNC(inode))
4077		ext4_handle_sync(handle);
4078
4079	inode->i_mtime = inode->i_ctime = current_time(inode);
4080	ret2 = ext4_mark_inode_dirty(handle, inode);
4081	if (unlikely(ret2))
4082		ret = ret2;
4083	if (ret >= 0)
4084		ext4_update_inode_fsync_trans(handle, inode, 1);
4085out_stop:
4086	ext4_journal_stop(handle);
4087out_dio:
4088	up_write(&EXT4_I(inode)->i_mmap_sem);
4089out_mutex:
4090	inode_unlock(inode);
4091	return ret;
4092}
4093
4094int ext4_inode_attach_jinode(struct inode *inode)
4095{
4096	struct ext4_inode_info *ei = EXT4_I(inode);
4097	struct jbd2_inode *jinode;
4098
4099	if (ei->jinode || !EXT4_SB(inode->i_sb)->s_journal)
4100		return 0;
4101
4102	jinode = jbd2_alloc_inode(GFP_KERNEL);
4103	spin_lock(&inode->i_lock);
4104	if (!ei->jinode) {
4105		if (!jinode) {
4106			spin_unlock(&inode->i_lock);
4107			return -ENOMEM;
4108		}
4109		ei->jinode = jinode;
4110		jbd2_journal_init_jbd_inode(ei->jinode, inode);
4111		jinode = NULL;
4112	}
4113	spin_unlock(&inode->i_lock);
4114	if (unlikely(jinode != NULL))
4115		jbd2_free_inode(jinode);
4116	return 0;
4117}
4118
4119/*
4120 * ext4_truncate()
4121 *
4122 * We block out ext4_get_block() block instantiations across the entire
4123 * transaction, and VFS/VM ensures that ext4_truncate() cannot run
4124 * simultaneously on behalf of the same inode.
4125 *
4126 * As we work through the truncate and commit bits of it to the journal there
4127 * is one core, guiding principle: the file's tree must always be consistent on
4128 * disk.  We must be able to restart the truncate after a crash.
4129 *
4130 * The file's tree may be transiently inconsistent in memory (although it
4131 * probably isn't), but whenever we close off and commit a journal transaction,
4132 * the contents of (the filesystem + the journal) must be consistent and
4133 * restartable.  It's pretty simple, really: bottom up, right to left (although
4134 * left-to-right works OK too).
4135 *
4136 * Note that at recovery time, journal replay occurs *before* the restart of
4137 * truncate against the orphan inode list.
4138 *
4139 * The committed inode has the new, desired i_size (which is the same as
4140 * i_disksize in this case).  After a crash, ext4_orphan_cleanup() will see
4141 * that this inode's truncate did not complete and it will again call
4142 * ext4_truncate() to have another go.  So there will be instantiated blocks
4143 * to the right of the truncation point in a crashed ext4 filesystem.  But
4144 * that's fine - as long as they are linked from the inode, the post-crash
4145 * ext4_truncate() run will find them and release them.
4146 */
4147int ext4_truncate(struct inode *inode)
4148{
4149	struct ext4_inode_info *ei = EXT4_I(inode);
4150	unsigned int credits;
4151	int err = 0, err2;
4152	handle_t *handle;
4153	struct address_space *mapping = inode->i_mapping;
4154
4155	/*
4156	 * There is a possibility that we're either freeing the inode
4157	 * or it's a completely new inode. In those cases we might not
4158	 * have i_mutex locked because it's not necessary.
4159	 */
4160	if (!(inode->i_state & (I_NEW|I_FREEING)))
4161		WARN_ON(!inode_is_locked(inode));
4162	trace_ext4_truncate_enter(inode);
4163
4164	if (!ext4_can_truncate(inode))
4165		goto out_trace;
4166
4167	if (inode->i_size == 0 && !test_opt(inode->i_sb, NO_AUTO_DA_ALLOC))
4168		ext4_set_inode_state(inode, EXT4_STATE_DA_ALLOC_CLOSE);
4169
4170	if (ext4_has_inline_data(inode)) {
4171		int has_inline = 1;
4172
4173		err = ext4_inline_data_truncate(inode, &has_inline);
4174		if (err || has_inline)
4175			goto out_trace;
4176	}
4177
4178	/* If we zero-out tail of the page, we have to create jinode for jbd2 */
4179	if (inode->i_size & (inode->i_sb->s_blocksize - 1)) {
4180		if (ext4_inode_attach_jinode(inode) < 0)
 
4181			goto out_trace;
4182	}
4183
4184	if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
4185		credits = ext4_writepage_trans_blocks(inode);
4186	else
4187		credits = ext4_blocks_for_truncate(inode);
4188
4189	handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE, credits);
4190	if (IS_ERR(handle)) {
4191		err = PTR_ERR(handle);
4192		goto out_trace;
4193	}
4194
4195	if (inode->i_size & (inode->i_sb->s_blocksize - 1))
4196		ext4_block_truncate_page(handle, mapping, inode->i_size);
4197
4198	/*
4199	 * We add the inode to the orphan list, so that if this
4200	 * truncate spans multiple transactions, and we crash, we will
4201	 * resume the truncate when the filesystem recovers.  It also
4202	 * marks the inode dirty, to catch the new size.
4203	 *
4204	 * Implication: the file must always be in a sane, consistent
4205	 * truncatable state while each transaction commits.
4206	 */
4207	err = ext4_orphan_add(handle, inode);
4208	if (err)
4209		goto out_stop;
4210
4211	down_write(&EXT4_I(inode)->i_data_sem);
4212
4213	ext4_discard_preallocations(inode, 0);
4214
4215	if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
4216		err = ext4_ext_truncate(handle, inode);
4217	else
4218		ext4_ind_truncate(handle, inode);
4219
4220	up_write(&ei->i_data_sem);
4221	if (err)
4222		goto out_stop;
4223
4224	if (IS_SYNC(inode))
4225		ext4_handle_sync(handle);
4226
4227out_stop:
4228	/*
4229	 * If this was a simple ftruncate() and the file will remain alive,
4230	 * then we need to clear up the orphan record which we created above.
4231	 * However, if this was a real unlink then we were called by
4232	 * ext4_evict_inode(), and we allow that function to clean up the
4233	 * orphan info for us.
4234	 */
4235	if (inode->i_nlink)
4236		ext4_orphan_del(handle, inode);
4237
4238	inode->i_mtime = inode->i_ctime = current_time(inode);
4239	err2 = ext4_mark_inode_dirty(handle, inode);
4240	if (unlikely(err2 && !err))
4241		err = err2;
4242	ext4_journal_stop(handle);
4243
4244out_trace:
4245	trace_ext4_truncate_exit(inode);
4246	return err;
4247}
4248
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
4249/*
4250 * ext4_get_inode_loc returns with an extra refcount against the inode's
4251 * underlying buffer_head on success. If 'in_mem' is true, we have all
4252 * data in memory that is needed to recreate the on-disk version of this
4253 * inode.
4254 */
4255static int __ext4_get_inode_loc(struct inode *inode,
4256				struct ext4_iloc *iloc, int in_mem)
 
4257{
4258	struct ext4_group_desc	*gdp;
4259	struct buffer_head	*bh;
4260	struct super_block	*sb = inode->i_sb;
4261	ext4_fsblk_t		block;
4262	struct blk_plug		plug;
4263	int			inodes_per_block, inode_offset;
4264
4265	iloc->bh = NULL;
4266	if (inode->i_ino < EXT4_ROOT_INO ||
4267	    inode->i_ino > le32_to_cpu(EXT4_SB(sb)->s_es->s_inodes_count))
4268		return -EFSCORRUPTED;
4269
4270	iloc->block_group = (inode->i_ino - 1) / EXT4_INODES_PER_GROUP(sb);
4271	gdp = ext4_get_group_desc(sb, iloc->block_group, NULL);
4272	if (!gdp)
4273		return -EIO;
4274
4275	/*
4276	 * Figure out the offset within the block group inode table
4277	 */
4278	inodes_per_block = EXT4_SB(sb)->s_inodes_per_block;
4279	inode_offset = ((inode->i_ino - 1) %
4280			EXT4_INODES_PER_GROUP(sb));
4281	block = ext4_inode_table(sb, gdp) + (inode_offset / inodes_per_block);
4282	iloc->offset = (inode_offset % inodes_per_block) * EXT4_INODE_SIZE(sb);
4283
 
 
 
 
 
 
 
 
 
4284	bh = sb_getblk(sb, block);
4285	if (unlikely(!bh))
4286		return -ENOMEM;
4287	if (ext4_simulate_fail(sb, EXT4_SIM_INODE_EIO))
4288		goto simulate_eio;
4289	if (!buffer_uptodate(bh)) {
4290		lock_buffer(bh);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
4291
4292		/*
4293		 * If the buffer has the write error flag, we have failed
4294		 * to write out another inode in the same block.  In this
4295		 * case, we don't have to read the block because we may
4296		 * read the old inode data successfully.
4297		 */
4298		if (buffer_write_io_error(bh) && !buffer_uptodate(bh))
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
4299			set_buffer_uptodate(bh);
4300
4301		if (buffer_uptodate(bh)) {
4302			/* someone brought it uptodate while we waited */
4303			unlock_buffer(bh);
4304			goto has_buffer;
4305		}
4306
4307		/*
4308		 * If we have all information of the inode in memory and this
4309		 * is the only valid inode in the block, we need not read the
4310		 * block.
4311		 */
4312		if (in_mem) {
4313			struct buffer_head *bitmap_bh;
4314			int i, start;
4315
4316			start = inode_offset & ~(inodes_per_block - 1);
4317
4318			/* Is the inode bitmap in cache? */
4319			bitmap_bh = sb_getblk(sb, ext4_inode_bitmap(sb, gdp));
4320			if (unlikely(!bitmap_bh))
4321				goto make_io;
4322
4323			/*
4324			 * If the inode bitmap isn't in cache then the
4325			 * optimisation may end up performing two reads instead
4326			 * of one, so skip it.
4327			 */
4328			if (!buffer_uptodate(bitmap_bh)) {
4329				brelse(bitmap_bh);
4330				goto make_io;
4331			}
4332			for (i = start; i < start + inodes_per_block; i++) {
4333				if (i == inode_offset)
4334					continue;
4335				if (ext4_test_bit(i, bitmap_bh->b_data))
4336					break;
4337			}
4338			brelse(bitmap_bh);
4339			if (i == start + inodes_per_block) {
4340				/* all other inodes are free, so skip I/O */
4341				memset(bh->b_data, 0, bh->b_size);
4342				set_buffer_uptodate(bh);
4343				unlock_buffer(bh);
4344				goto has_buffer;
4345			}
4346		}
4347
4348make_io:
4349		/*
4350		 * If we need to do any I/O, try to pre-readahead extra
4351		 * blocks from the inode table.
4352		 */
4353		blk_start_plug(&plug);
4354		if (EXT4_SB(sb)->s_inode_readahead_blks) {
4355			ext4_fsblk_t b, end, table;
4356			unsigned num;
4357			__u32 ra_blks = EXT4_SB(sb)->s_inode_readahead_blks;
4358
4359			table = ext4_inode_table(sb, gdp);
4360			/* s_inode_readahead_blks is always a power of 2 */
4361			b = block & ~((ext4_fsblk_t) ra_blks - 1);
4362			if (table > b)
4363				b = table;
4364			end = b + ra_blks;
4365			num = EXT4_INODES_PER_GROUP(sb);
4366			if (ext4_has_group_desc_csum(sb))
4367				num -= ext4_itable_unused_count(sb, gdp);
4368			table += num / inodes_per_block;
4369			if (end > table)
4370				end = table;
4371			while (b <= end)
4372				sb_breadahead_unmovable(sb, b++);
4373		}
4374
4375		/*
4376		 * There are other valid inodes in the buffer, this inode
4377		 * has in-inode xattrs, or we don't have this inode in memory.
4378		 * Read the block from disk.
4379		 */
4380		trace_ext4_load_inode(inode);
4381		get_bh(bh);
4382		bh->b_end_io = end_buffer_read_sync;
4383		submit_bh(REQ_OP_READ, REQ_META | REQ_PRIO, bh);
4384		blk_finish_plug(&plug);
4385		wait_on_buffer(bh);
4386		if (!buffer_uptodate(bh)) {
4387		simulate_eio:
4388			ext4_error_inode_block(inode, block, EIO,
4389					       "unable to read itable block");
4390			brelse(bh);
4391			return -EIO;
4392		}
4393	}
4394has_buffer:
4395	iloc->bh = bh;
4396	return 0;
4397}
4398
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
4399int ext4_get_inode_loc(struct inode *inode, struct ext4_iloc *iloc)
4400{
4401	/* We have all inode data except xattrs in memory here. */
4402	return __ext4_get_inode_loc(inode, iloc,
4403		!ext4_test_inode_state(inode, EXT4_STATE_XATTR));
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
4404}
4405
4406static bool ext4_should_enable_dax(struct inode *inode)
4407{
4408	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
4409
4410	if (test_opt2(inode->i_sb, DAX_NEVER))
4411		return false;
4412	if (!S_ISREG(inode->i_mode))
4413		return false;
4414	if (ext4_should_journal_data(inode))
4415		return false;
4416	if (ext4_has_inline_data(inode))
4417		return false;
4418	if (ext4_test_inode_flag(inode, EXT4_INODE_ENCRYPT))
4419		return false;
4420	if (ext4_test_inode_flag(inode, EXT4_INODE_VERITY))
4421		return false;
4422	if (!test_bit(EXT4_FLAGS_BDEV_IS_DAX, &sbi->s_ext4_flags))
4423		return false;
4424	if (test_opt(inode->i_sb, DAX_ALWAYS))
4425		return true;
4426
4427	return ext4_test_inode_flag(inode, EXT4_INODE_DAX);
4428}
4429
4430void ext4_set_inode_flags(struct inode *inode, bool init)
4431{
4432	unsigned int flags = EXT4_I(inode)->i_flags;
4433	unsigned int new_fl = 0;
4434
4435	WARN_ON_ONCE(IS_DAX(inode) && init);
4436
4437	if (flags & EXT4_SYNC_FL)
4438		new_fl |= S_SYNC;
4439	if (flags & EXT4_APPEND_FL)
4440		new_fl |= S_APPEND;
4441	if (flags & EXT4_IMMUTABLE_FL)
4442		new_fl |= S_IMMUTABLE;
4443	if (flags & EXT4_NOATIME_FL)
4444		new_fl |= S_NOATIME;
4445	if (flags & EXT4_DIRSYNC_FL)
4446		new_fl |= S_DIRSYNC;
4447
4448	/* Because of the way inode_set_flags() works we must preserve S_DAX
4449	 * here if already set. */
4450	new_fl |= (inode->i_flags & S_DAX);
4451	if (init && ext4_should_enable_dax(inode))
4452		new_fl |= S_DAX;
4453
4454	if (flags & EXT4_ENCRYPT_FL)
4455		new_fl |= S_ENCRYPTED;
4456	if (flags & EXT4_CASEFOLD_FL)
4457		new_fl |= S_CASEFOLD;
4458	if (flags & EXT4_VERITY_FL)
4459		new_fl |= S_VERITY;
4460	inode_set_flags(inode, new_fl,
4461			S_SYNC|S_APPEND|S_IMMUTABLE|S_NOATIME|S_DIRSYNC|S_DAX|
4462			S_ENCRYPTED|S_CASEFOLD|S_VERITY);
4463}
4464
4465static blkcnt_t ext4_inode_blocks(struct ext4_inode *raw_inode,
4466				  struct ext4_inode_info *ei)
4467{
4468	blkcnt_t i_blocks ;
4469	struct inode *inode = &(ei->vfs_inode);
4470	struct super_block *sb = inode->i_sb;
4471
4472	if (ext4_has_feature_huge_file(sb)) {
4473		/* we are using combined 48 bit field */
4474		i_blocks = ((u64)le16_to_cpu(raw_inode->i_blocks_high)) << 32 |
4475					le32_to_cpu(raw_inode->i_blocks_lo);
4476		if (ext4_test_inode_flag(inode, EXT4_INODE_HUGE_FILE)) {
4477			/* i_blocks represent file system block size */
4478			return i_blocks  << (inode->i_blkbits - 9);
4479		} else {
4480			return i_blocks;
4481		}
4482	} else {
4483		return le32_to_cpu(raw_inode->i_blocks_lo);
4484	}
4485}
4486
4487static inline int ext4_iget_extra_inode(struct inode *inode,
4488					 struct ext4_inode *raw_inode,
4489					 struct ext4_inode_info *ei)
4490{
4491	__le32 *magic = (void *)raw_inode +
4492			EXT4_GOOD_OLD_INODE_SIZE + ei->i_extra_isize;
4493
4494	if (EXT4_GOOD_OLD_INODE_SIZE + ei->i_extra_isize + sizeof(__le32) <=
4495	    EXT4_INODE_SIZE(inode->i_sb) &&
4496	    *magic == cpu_to_le32(EXT4_XATTR_MAGIC)) {
4497		ext4_set_inode_state(inode, EXT4_STATE_XATTR);
4498		return ext4_find_inline_data_nolock(inode);
4499	} else
4500		EXT4_I(inode)->i_inline_off = 0;
4501	return 0;
4502}
4503
4504int ext4_get_projid(struct inode *inode, kprojid_t *projid)
4505{
4506	if (!ext4_has_feature_project(inode->i_sb))
4507		return -EOPNOTSUPP;
4508	*projid = EXT4_I(inode)->i_projid;
4509	return 0;
4510}
4511
4512/*
4513 * ext4 has self-managed i_version for ea inodes, it stores the lower 32bit of
4514 * refcount in i_version, so use raw values if inode has EXT4_EA_INODE_FL flag
4515 * set.
4516 */
4517static inline void ext4_inode_set_iversion_queried(struct inode *inode, u64 val)
4518{
4519	if (unlikely(EXT4_I(inode)->i_flags & EXT4_EA_INODE_FL))
4520		inode_set_iversion_raw(inode, val);
4521	else
4522		inode_set_iversion_queried(inode, val);
4523}
4524static inline u64 ext4_inode_peek_iversion(const struct inode *inode)
4525{
4526	if (unlikely(EXT4_I(inode)->i_flags & EXT4_EA_INODE_FL))
4527		return inode_peek_iversion_raw(inode);
4528	else
4529		return inode_peek_iversion(inode);
4530}
4531
4532struct inode *__ext4_iget(struct super_block *sb, unsigned long ino,
4533			  ext4_iget_flags flags, const char *function,
4534			  unsigned int line)
4535{
4536	struct ext4_iloc iloc;
4537	struct ext4_inode *raw_inode;
4538	struct ext4_inode_info *ei;
 
4539	struct inode *inode;
4540	journal_t *journal = EXT4_SB(sb)->s_journal;
4541	long ret;
4542	loff_t size;
4543	int block;
4544	uid_t i_uid;
4545	gid_t i_gid;
4546	projid_t i_projid;
4547
4548	if ((!(flags & EXT4_IGET_SPECIAL) &&
4549	     (ino < EXT4_FIRST_INO(sb) && ino != EXT4_ROOT_INO)) ||
 
 
 
 
4550	    (ino < EXT4_ROOT_INO) ||
4551	    (ino > le32_to_cpu(EXT4_SB(sb)->s_es->s_inodes_count))) {
4552		if (flags & EXT4_IGET_HANDLE)
4553			return ERR_PTR(-ESTALE);
4554		__ext4_error(sb, function, line, EFSCORRUPTED, 0,
4555			     "inode #%lu: comm %s: iget: illegal inode #",
4556			     ino, current->comm);
4557		return ERR_PTR(-EFSCORRUPTED);
4558	}
4559
4560	inode = iget_locked(sb, ino);
4561	if (!inode)
4562		return ERR_PTR(-ENOMEM);
4563	if (!(inode->i_state & I_NEW))
4564		return inode;
4565
4566	ei = EXT4_I(inode);
4567	iloc.bh = NULL;
4568
4569	ret = __ext4_get_inode_loc(inode, &iloc, 0);
4570	if (ret < 0)
4571		goto bad_inode;
4572	raw_inode = ext4_raw_inode(&iloc);
4573
4574	if ((ino == EXT4_ROOT_INO) && (raw_inode->i_links_count == 0)) {
4575		ext4_error_inode(inode, function, line, 0,
4576				 "iget: root inode unallocated");
4577		ret = -EFSCORRUPTED;
4578		goto bad_inode;
4579	}
4580
4581	if ((flags & EXT4_IGET_HANDLE) &&
4582	    (raw_inode->i_links_count == 0) && (raw_inode->i_mode == 0)) {
4583		ret = -ESTALE;
4584		goto bad_inode;
4585	}
4586
4587	if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE) {
4588		ei->i_extra_isize = le16_to_cpu(raw_inode->i_extra_isize);
4589		if (EXT4_GOOD_OLD_INODE_SIZE + ei->i_extra_isize >
4590			EXT4_INODE_SIZE(inode->i_sb) ||
4591		    (ei->i_extra_isize & 3)) {
4592			ext4_error_inode(inode, function, line, 0,
4593					 "iget: bad extra_isize %u "
4594					 "(inode size %u)",
4595					 ei->i_extra_isize,
4596					 EXT4_INODE_SIZE(inode->i_sb));
4597			ret = -EFSCORRUPTED;
4598			goto bad_inode;
4599		}
4600	} else
4601		ei->i_extra_isize = 0;
4602
4603	/* Precompute checksum seed for inode metadata */
4604	if (ext4_has_metadata_csum(sb)) {
4605		struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
4606		__u32 csum;
4607		__le32 inum = cpu_to_le32(inode->i_ino);
4608		__le32 gen = raw_inode->i_generation;
4609		csum = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)&inum,
4610				   sizeof(inum));
4611		ei->i_csum_seed = ext4_chksum(sbi, csum, (__u8 *)&gen,
4612					      sizeof(gen));
4613	}
4614
4615	if (!ext4_inode_csum_verify(inode, raw_inode, ei) ||
4616	    ext4_simulate_fail(sb, EXT4_SIM_INODE_CRC)) {
4617		ext4_error_inode_err(inode, function, line, 0, EFSBADCRC,
4618				     "iget: checksum invalid");
 
4619		ret = -EFSBADCRC;
4620		goto bad_inode;
4621	}
4622
4623	inode->i_mode = le16_to_cpu(raw_inode->i_mode);
4624	i_uid = (uid_t)le16_to_cpu(raw_inode->i_uid_low);
4625	i_gid = (gid_t)le16_to_cpu(raw_inode->i_gid_low);
4626	if (ext4_has_feature_project(sb) &&
4627	    EXT4_INODE_SIZE(sb) > EXT4_GOOD_OLD_INODE_SIZE &&
4628	    EXT4_FITS_IN_INODE(raw_inode, ei, i_projid))
4629		i_projid = (projid_t)le32_to_cpu(raw_inode->i_projid);
4630	else
4631		i_projid = EXT4_DEF_PROJID;
4632
4633	if (!(test_opt(inode->i_sb, NO_UID32))) {
4634		i_uid |= le16_to_cpu(raw_inode->i_uid_high) << 16;
4635		i_gid |= le16_to_cpu(raw_inode->i_gid_high) << 16;
4636	}
4637	i_uid_write(inode, i_uid);
4638	i_gid_write(inode, i_gid);
4639	ei->i_projid = make_kprojid(&init_user_ns, i_projid);
4640	set_nlink(inode, le16_to_cpu(raw_inode->i_links_count));
4641
4642	ext4_clear_state_flags(ei);	/* Only relevant on 32-bit archs */
4643	ei->i_inline_off = 0;
4644	ei->i_dir_start_lookup = 0;
4645	ei->i_dtime = le32_to_cpu(raw_inode->i_dtime);
4646	/* We now have enough fields to check if the inode was active or not.
4647	 * This is needed because nfsd might try to access dead inodes
4648	 * the test is that same one that e2fsck uses
4649	 * NeilBrown 1999oct15
4650	 */
4651	if (inode->i_nlink == 0) {
4652		if ((inode->i_mode == 0 ||
4653		     !(EXT4_SB(inode->i_sb)->s_mount_state & EXT4_ORPHAN_FS)) &&
4654		    ino != EXT4_BOOT_LOADER_INO) {
4655			/* this inode is deleted */
4656			ret = -ESTALE;
4657			goto bad_inode;
4658		}
4659		/* The only unlinked inodes we let through here have
4660		 * valid i_mode and are being read by the orphan
4661		 * recovery code: that's fine, we're about to complete
4662		 * the process of deleting those.
4663		 * OR it is the EXT4_BOOT_LOADER_INO which is
4664		 * not initialized on a new filesystem. */
4665	}
4666	ei->i_flags = le32_to_cpu(raw_inode->i_flags);
4667	ext4_set_inode_flags(inode, true);
4668	inode->i_blocks = ext4_inode_blocks(raw_inode, ei);
4669	ei->i_file_acl = le32_to_cpu(raw_inode->i_file_acl_lo);
4670	if (ext4_has_feature_64bit(sb))
4671		ei->i_file_acl |=
4672			((__u64)le16_to_cpu(raw_inode->i_file_acl_high)) << 32;
4673	inode->i_size = ext4_isize(sb, raw_inode);
4674	if ((size = i_size_read(inode)) < 0) {
4675		ext4_error_inode(inode, function, line, 0,
4676				 "iget: bad i_size value: %lld", size);
4677		ret = -EFSCORRUPTED;
4678		goto bad_inode;
4679	}
4680	/*
4681	 * If dir_index is not enabled but there's dir with INDEX flag set,
4682	 * we'd normally treat htree data as empty space. But with metadata
4683	 * checksumming that corrupts checksums so forbid that.
4684	 */
4685	if (!ext4_has_feature_dir_index(sb) && ext4_has_metadata_csum(sb) &&
4686	    ext4_test_inode_flag(inode, EXT4_INODE_INDEX)) {
4687		ext4_error_inode(inode, function, line, 0,
4688			 "iget: Dir with htree data on filesystem without dir_index feature.");
4689		ret = -EFSCORRUPTED;
4690		goto bad_inode;
4691	}
4692	ei->i_disksize = inode->i_size;
4693#ifdef CONFIG_QUOTA
4694	ei->i_reserved_quota = 0;
4695#endif
4696	inode->i_generation = le32_to_cpu(raw_inode->i_generation);
4697	ei->i_block_group = iloc.block_group;
4698	ei->i_last_alloc_group = ~0;
4699	/*
4700	 * NOTE! The in-memory inode i_data array is in little-endian order
4701	 * even on big-endian machines: we do NOT byteswap the block numbers!
4702	 */
4703	for (block = 0; block < EXT4_N_BLOCKS; block++)
4704		ei->i_data[block] = raw_inode->i_block[block];
4705	INIT_LIST_HEAD(&ei->i_orphan);
 
4706
4707	/*
4708	 * Set transaction id's of transactions that have to be committed
4709	 * to finish f[data]sync. We set them to currently running transaction
4710	 * as we cannot be sure that the inode or some of its metadata isn't
4711	 * part of the transaction - the inode could have been reclaimed and
4712	 * now it is reread from disk.
4713	 */
4714	if (journal) {
4715		transaction_t *transaction;
4716		tid_t tid;
4717
4718		read_lock(&journal->j_state_lock);
4719		if (journal->j_running_transaction)
4720			transaction = journal->j_running_transaction;
4721		else
4722			transaction = journal->j_committing_transaction;
4723		if (transaction)
4724			tid = transaction->t_tid;
4725		else
4726			tid = journal->j_commit_sequence;
4727		read_unlock(&journal->j_state_lock);
4728		ei->i_sync_tid = tid;
4729		ei->i_datasync_tid = tid;
4730	}
4731
4732	if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE) {
4733		if (ei->i_extra_isize == 0) {
4734			/* The extra space is currently unused. Use it. */
4735			BUILD_BUG_ON(sizeof(struct ext4_inode) & 3);
4736			ei->i_extra_isize = sizeof(struct ext4_inode) -
4737					    EXT4_GOOD_OLD_INODE_SIZE;
4738		} else {
4739			ret = ext4_iget_extra_inode(inode, raw_inode, ei);
4740			if (ret)
4741				goto bad_inode;
4742		}
4743	}
4744
4745	EXT4_INODE_GET_XTIME(i_ctime, inode, raw_inode);
4746	EXT4_INODE_GET_XTIME(i_mtime, inode, raw_inode);
4747	EXT4_INODE_GET_XTIME(i_atime, inode, raw_inode);
4748	EXT4_EINODE_GET_XTIME(i_crtime, ei, raw_inode);
4749
4750	if (likely(!test_opt2(inode->i_sb, HURD_COMPAT))) {
4751		u64 ivers = le32_to_cpu(raw_inode->i_disk_version);
4752
4753		if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE) {
4754			if (EXT4_FITS_IN_INODE(raw_inode, ei, i_version_hi))
4755				ivers |=
4756		    (__u64)(le32_to_cpu(raw_inode->i_version_hi)) << 32;
4757		}
4758		ext4_inode_set_iversion_queried(inode, ivers);
4759	}
4760
4761	ret = 0;
4762	if (ei->i_file_acl &&
4763	    !ext4_inode_block_valid(inode, ei->i_file_acl, 1)) {
4764		ext4_error_inode(inode, function, line, 0,
4765				 "iget: bad extended attribute block %llu",
4766				 ei->i_file_acl);
4767		ret = -EFSCORRUPTED;
4768		goto bad_inode;
4769	} else if (!ext4_has_inline_data(inode)) {
4770		/* validate the block references in the inode */
4771		if (S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
4772		   (S_ISLNK(inode->i_mode) &&
4773		    !ext4_inode_is_fast_symlink(inode))) {
 
4774			if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
4775				ret = ext4_ext_check_inode(inode);
4776			else
4777				ret = ext4_ind_check_inode(inode);
4778		}
4779	}
4780	if (ret)
4781		goto bad_inode;
4782
4783	if (S_ISREG(inode->i_mode)) {
4784		inode->i_op = &ext4_file_inode_operations;
4785		inode->i_fop = &ext4_file_operations;
4786		ext4_set_aops(inode);
4787	} else if (S_ISDIR(inode->i_mode)) {
4788		inode->i_op = &ext4_dir_inode_operations;
4789		inode->i_fop = &ext4_dir_operations;
4790	} else if (S_ISLNK(inode->i_mode)) {
4791		/* VFS does not allow setting these so must be corruption */
4792		if (IS_APPEND(inode) || IS_IMMUTABLE(inode)) {
4793			ext4_error_inode(inode, function, line, 0,
4794					 "iget: immutable or append flags "
4795					 "not allowed on symlinks");
4796			ret = -EFSCORRUPTED;
4797			goto bad_inode;
4798		}
4799		if (IS_ENCRYPTED(inode)) {
4800			inode->i_op = &ext4_encrypted_symlink_inode_operations;
4801			ext4_set_aops(inode);
4802		} else if (ext4_inode_is_fast_symlink(inode)) {
4803			inode->i_link = (char *)ei->i_data;
4804			inode->i_op = &ext4_fast_symlink_inode_operations;
4805			nd_terminate_link(ei->i_data, inode->i_size,
4806				sizeof(ei->i_data) - 1);
4807		} else {
4808			inode->i_op = &ext4_symlink_inode_operations;
4809			ext4_set_aops(inode);
4810		}
4811		inode_nohighmem(inode);
4812	} else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode) ||
4813	      S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode)) {
4814		inode->i_op = &ext4_special_inode_operations;
4815		if (raw_inode->i_block[0])
4816			init_special_inode(inode, inode->i_mode,
4817			   old_decode_dev(le32_to_cpu(raw_inode->i_block[0])));
4818		else
4819			init_special_inode(inode, inode->i_mode,
4820			   new_decode_dev(le32_to_cpu(raw_inode->i_block[1])));
4821	} else if (ino == EXT4_BOOT_LOADER_INO) {
4822		make_bad_inode(inode);
4823	} else {
4824		ret = -EFSCORRUPTED;
4825		ext4_error_inode(inode, function, line, 0,
4826				 "iget: bogus i_mode (%o)", inode->i_mode);
4827		goto bad_inode;
4828	}
4829	if (IS_CASEFOLDED(inode) && !ext4_has_feature_casefold(inode->i_sb))
4830		ext4_error_inode(inode, function, line, 0,
4831				 "casefold flag without casefold feature");
4832	brelse(iloc.bh);
 
 
 
 
 
4833
 
4834	unlock_new_inode(inode);
4835	return inode;
4836
4837bad_inode:
4838	brelse(iloc.bh);
4839	iget_failed(inode);
4840	return ERR_PTR(ret);
4841}
4842
4843static int ext4_inode_blocks_set(handle_t *handle,
4844				struct ext4_inode *raw_inode,
4845				struct ext4_inode_info *ei)
4846{
4847	struct inode *inode = &(ei->vfs_inode);
4848	u64 i_blocks = READ_ONCE(inode->i_blocks);
4849	struct super_block *sb = inode->i_sb;
4850
4851	if (i_blocks <= ~0U) {
4852		/*
4853		 * i_blocks can be represented in a 32 bit variable
4854		 * as multiple of 512 bytes
4855		 */
4856		raw_inode->i_blocks_lo   = cpu_to_le32(i_blocks);
4857		raw_inode->i_blocks_high = 0;
4858		ext4_clear_inode_flag(inode, EXT4_INODE_HUGE_FILE);
4859		return 0;
4860	}
4861	if (!ext4_has_feature_huge_file(sb))
4862		return -EFBIG;
4863
4864	if (i_blocks <= 0xffffffffffffULL) {
4865		/*
4866		 * i_blocks can be represented in a 48 bit variable
4867		 * as multiple of 512 bytes
4868		 */
4869		raw_inode->i_blocks_lo   = cpu_to_le32(i_blocks);
4870		raw_inode->i_blocks_high = cpu_to_le16(i_blocks >> 32);
4871		ext4_clear_inode_flag(inode, EXT4_INODE_HUGE_FILE);
4872	} else {
4873		ext4_set_inode_flag(inode, EXT4_INODE_HUGE_FILE);
4874		/* i_block is stored in file system block size */
4875		i_blocks = i_blocks >> (inode->i_blkbits - 9);
4876		raw_inode->i_blocks_lo   = cpu_to_le32(i_blocks);
4877		raw_inode->i_blocks_high = cpu_to_le16(i_blocks >> 32);
4878	}
4879	return 0;
4880}
4881
4882static void __ext4_update_other_inode_time(struct super_block *sb,
4883					   unsigned long orig_ino,
4884					   unsigned long ino,
4885					   struct ext4_inode *raw_inode)
4886{
4887	struct inode *inode;
4888
4889	inode = find_inode_by_ino_rcu(sb, ino);
4890	if (!inode)
4891		return;
4892
4893	if ((inode->i_state & (I_FREEING | I_WILL_FREE | I_NEW |
4894			       I_DIRTY_INODE)) ||
4895	    ((inode->i_state & I_DIRTY_TIME) == 0))
4896		return;
4897
4898	spin_lock(&inode->i_lock);
4899	if (((inode->i_state & (I_FREEING | I_WILL_FREE | I_NEW |
4900				I_DIRTY_INODE)) == 0) &&
4901	    (inode->i_state & I_DIRTY_TIME)) {
4902		struct ext4_inode_info	*ei = EXT4_I(inode);
4903
4904		inode->i_state &= ~I_DIRTY_TIME;
4905		spin_unlock(&inode->i_lock);
4906
4907		spin_lock(&ei->i_raw_lock);
4908		EXT4_INODE_SET_XTIME(i_ctime, inode, raw_inode);
4909		EXT4_INODE_SET_XTIME(i_mtime, inode, raw_inode);
4910		EXT4_INODE_SET_XTIME(i_atime, inode, raw_inode);
4911		ext4_inode_csum_set(inode, raw_inode, ei);
4912		spin_unlock(&ei->i_raw_lock);
4913		trace_ext4_other_inode_update_time(inode, orig_ino);
4914		return;
4915	}
4916	spin_unlock(&inode->i_lock);
4917}
4918
4919/*
4920 * Opportunistically update the other time fields for other inodes in
4921 * the same inode table block.
4922 */
4923static void ext4_update_other_inodes_time(struct super_block *sb,
4924					  unsigned long orig_ino, char *buf)
4925{
4926	unsigned long ino;
4927	int i, inodes_per_block = EXT4_SB(sb)->s_inodes_per_block;
4928	int inode_size = EXT4_INODE_SIZE(sb);
4929
4930	/*
4931	 * Calculate the first inode in the inode table block.  Inode
4932	 * numbers are one-based.  That is, the first inode in a block
4933	 * (assuming 4k blocks and 256 byte inodes) is (n*16 + 1).
4934	 */
4935	ino = ((orig_ino - 1) & ~(inodes_per_block - 1)) + 1;
4936	rcu_read_lock();
4937	for (i = 0; i < inodes_per_block; i++, ino++, buf += inode_size) {
4938		if (ino == orig_ino)
4939			continue;
4940		__ext4_update_other_inode_time(sb, orig_ino, ino,
4941					       (struct ext4_inode *)buf);
4942	}
4943	rcu_read_unlock();
4944}
4945
4946/*
4947 * Post the struct inode info into an on-disk inode location in the
4948 * buffer-cache.  This gobbles the caller's reference to the
4949 * buffer_head in the inode location struct.
4950 *
4951 * The caller must have write access to iloc->bh.
4952 */
4953static int ext4_do_update_inode(handle_t *handle,
4954				struct inode *inode,
4955				struct ext4_iloc *iloc)
4956{
4957	struct ext4_inode *raw_inode = ext4_raw_inode(iloc);
4958	struct ext4_inode_info *ei = EXT4_I(inode);
4959	struct buffer_head *bh = iloc->bh;
4960	struct super_block *sb = inode->i_sb;
4961	int err = 0, rc, block;
4962	int need_datasync = 0, set_large_file = 0;
4963	uid_t i_uid;
4964	gid_t i_gid;
4965	projid_t i_projid;
4966
4967	spin_lock(&ei->i_raw_lock);
4968
4969	/* For fields not tracked in the in-memory inode,
4970	 * initialise them to zero for new inodes. */
 
 
4971	if (ext4_test_inode_state(inode, EXT4_STATE_NEW))
4972		memset(raw_inode, 0, EXT4_SB(inode->i_sb)->s_inode_size);
4973
4974	raw_inode->i_mode = cpu_to_le16(inode->i_mode);
4975	i_uid = i_uid_read(inode);
4976	i_gid = i_gid_read(inode);
4977	i_projid = from_kprojid(&init_user_ns, ei->i_projid);
4978	if (!(test_opt(inode->i_sb, NO_UID32))) {
4979		raw_inode->i_uid_low = cpu_to_le16(low_16_bits(i_uid));
4980		raw_inode->i_gid_low = cpu_to_le16(low_16_bits(i_gid));
4981/*
4982 * Fix up interoperability with old kernels. Otherwise, old inodes get
4983 * re-used with the upper 16 bits of the uid/gid intact
4984 */
4985		if (ei->i_dtime && list_empty(&ei->i_orphan)) {
4986			raw_inode->i_uid_high = 0;
4987			raw_inode->i_gid_high = 0;
4988		} else {
4989			raw_inode->i_uid_high =
4990				cpu_to_le16(high_16_bits(i_uid));
4991			raw_inode->i_gid_high =
4992				cpu_to_le16(high_16_bits(i_gid));
4993		}
4994	} else {
4995		raw_inode->i_uid_low = cpu_to_le16(fs_high2lowuid(i_uid));
4996		raw_inode->i_gid_low = cpu_to_le16(fs_high2lowgid(i_gid));
4997		raw_inode->i_uid_high = 0;
4998		raw_inode->i_gid_high = 0;
4999	}
5000	raw_inode->i_links_count = cpu_to_le16(inode->i_nlink);
5001
5002	EXT4_INODE_SET_XTIME(i_ctime, inode, raw_inode);
5003	EXT4_INODE_SET_XTIME(i_mtime, inode, raw_inode);
5004	EXT4_INODE_SET_XTIME(i_atime, inode, raw_inode);
5005	EXT4_EINODE_SET_XTIME(i_crtime, ei, raw_inode);
5006
5007	err = ext4_inode_blocks_set(handle, raw_inode, ei);
5008	if (err) {
5009		spin_unlock(&ei->i_raw_lock);
5010		goto out_brelse;
5011	}
5012	raw_inode->i_dtime = cpu_to_le32(ei->i_dtime);
5013	raw_inode->i_flags = cpu_to_le32(ei->i_flags & 0xFFFFFFFF);
5014	if (likely(!test_opt2(inode->i_sb, HURD_COMPAT)))
5015		raw_inode->i_file_acl_high =
5016			cpu_to_le16(ei->i_file_acl >> 32);
5017	raw_inode->i_file_acl_lo = cpu_to_le32(ei->i_file_acl);
5018	if (READ_ONCE(ei->i_disksize) != ext4_isize(inode->i_sb, raw_inode)) {
5019		ext4_isize_set(raw_inode, ei->i_disksize);
5020		need_datasync = 1;
5021	}
5022	if (ei->i_disksize > 0x7fffffffULL) {
5023		if (!ext4_has_feature_large_file(sb) ||
5024				EXT4_SB(sb)->s_es->s_rev_level ==
5025		    cpu_to_le32(EXT4_GOOD_OLD_REV))
5026			set_large_file = 1;
5027	}
5028	raw_inode->i_generation = cpu_to_le32(inode->i_generation);
5029	if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode)) {
5030		if (old_valid_dev(inode->i_rdev)) {
5031			raw_inode->i_block[0] =
5032				cpu_to_le32(old_encode_dev(inode->i_rdev));
5033			raw_inode->i_block[1] = 0;
5034		} else {
5035			raw_inode->i_block[0] = 0;
5036			raw_inode->i_block[1] =
5037				cpu_to_le32(new_encode_dev(inode->i_rdev));
5038			raw_inode->i_block[2] = 0;
5039		}
5040	} else if (!ext4_has_inline_data(inode)) {
5041		for (block = 0; block < EXT4_N_BLOCKS; block++)
5042			raw_inode->i_block[block] = ei->i_data[block];
5043	}
5044
5045	if (likely(!test_opt2(inode->i_sb, HURD_COMPAT))) {
5046		u64 ivers = ext4_inode_peek_iversion(inode);
5047
5048		raw_inode->i_disk_version = cpu_to_le32(ivers);
5049		if (ei->i_extra_isize) {
5050			if (EXT4_FITS_IN_INODE(raw_inode, ei, i_version_hi))
5051				raw_inode->i_version_hi =
5052					cpu_to_le32(ivers >> 32);
5053			raw_inode->i_extra_isize =
5054				cpu_to_le16(ei->i_extra_isize);
5055		}
5056	}
5057
5058	BUG_ON(!ext4_has_feature_project(inode->i_sb) &&
5059	       i_projid != EXT4_DEF_PROJID);
5060
5061	if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE &&
5062	    EXT4_FITS_IN_INODE(raw_inode, ei, i_projid))
5063		raw_inode->i_projid = cpu_to_le32(i_projid);
5064
5065	ext4_inode_csum_set(inode, raw_inode, ei);
5066	spin_unlock(&ei->i_raw_lock);
5067	if (inode->i_sb->s_flags & SB_LAZYTIME)
5068		ext4_update_other_inodes_time(inode->i_sb, inode->i_ino,
5069					      bh->b_data);
5070
5071	BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
5072	rc = ext4_handle_dirty_metadata(handle, NULL, bh);
5073	if (!err)
5074		err = rc;
5075	ext4_clear_inode_state(inode, EXT4_STATE_NEW);
5076	if (set_large_file) {
5077		BUFFER_TRACE(EXT4_SB(sb)->s_sbh, "get write access");
5078		err = ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh);
 
 
5079		if (err)
5080			goto out_brelse;
 
5081		ext4_set_feature_large_file(sb);
 
 
5082		ext4_handle_sync(handle);
5083		err = ext4_handle_dirty_super(handle, sb);
 
5084	}
5085	ext4_update_inode_fsync_trans(handle, inode, need_datasync);
 
 
5086out_brelse:
5087	brelse(bh);
5088	ext4_std_error(inode->i_sb, err);
5089	return err;
5090}
5091
5092/*
5093 * ext4_write_inode()
5094 *
5095 * We are called from a few places:
5096 *
5097 * - Within generic_file_aio_write() -> generic_write_sync() for O_SYNC files.
5098 *   Here, there will be no transaction running. We wait for any running
5099 *   transaction to commit.
5100 *
5101 * - Within flush work (sys_sync(), kupdate and such).
5102 *   We wait on commit, if told to.
5103 *
5104 * - Within iput_final() -> write_inode_now()
5105 *   We wait on commit, if told to.
5106 *
5107 * In all cases it is actually safe for us to return without doing anything,
5108 * because the inode has been copied into a raw inode buffer in
5109 * ext4_mark_inode_dirty().  This is a correctness thing for WB_SYNC_ALL
5110 * writeback.
5111 *
5112 * Note that we are absolutely dependent upon all inode dirtiers doing the
5113 * right thing: they *must* call mark_inode_dirty() after dirtying info in
5114 * which we are interested.
5115 *
5116 * It would be a bug for them to not do this.  The code:
5117 *
5118 *	mark_inode_dirty(inode)
5119 *	stuff();
5120 *	inode->i_size = expr;
5121 *
5122 * is in error because write_inode() could occur while `stuff()' is running,
5123 * and the new i_size will be lost.  Plus the inode will no longer be on the
5124 * superblock's dirty inode list.
5125 */
5126int ext4_write_inode(struct inode *inode, struct writeback_control *wbc)
5127{
5128	int err;
5129
5130	if (WARN_ON_ONCE(current->flags & PF_MEMALLOC) ||
5131	    sb_rdonly(inode->i_sb))
5132		return 0;
5133
5134	if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb))))
5135		return -EIO;
5136
5137	if (EXT4_SB(inode->i_sb)->s_journal) {
5138		if (ext4_journal_current_handle()) {
5139			jbd_debug(1, "called recursively, non-PF_MEMALLOC!\n");
5140			dump_stack();
5141			return -EIO;
5142		}
5143
5144		/*
5145		 * No need to force transaction in WB_SYNC_NONE mode. Also
5146		 * ext4_sync_fs() will force the commit after everything is
5147		 * written.
5148		 */
5149		if (wbc->sync_mode != WB_SYNC_ALL || wbc->for_sync)
5150			return 0;
5151
5152		err = jbd2_complete_transaction(EXT4_SB(inode->i_sb)->s_journal,
5153						EXT4_I(inode)->i_sync_tid);
5154	} else {
5155		struct ext4_iloc iloc;
5156
5157		err = __ext4_get_inode_loc(inode, &iloc, 0);
5158		if (err)
5159			return err;
5160		/*
5161		 * sync(2) will flush the whole buffer cache. No need to do
5162		 * it here separately for each inode.
5163		 */
5164		if (wbc->sync_mode == WB_SYNC_ALL && !wbc->for_sync)
5165			sync_dirty_buffer(iloc.bh);
5166		if (buffer_req(iloc.bh) && !buffer_uptodate(iloc.bh)) {
5167			ext4_error_inode_block(inode, iloc.bh->b_blocknr, EIO,
5168					       "IO error syncing inode");
5169			err = -EIO;
5170		}
5171		brelse(iloc.bh);
5172	}
5173	return err;
5174}
5175
5176/*
5177 * In data=journal mode ext4_journalled_invalidatepage() may fail to invalidate
5178 * buffers that are attached to a page stradding i_size and are undergoing
5179 * commit. In that case we have to wait for commit to finish and try again.
5180 */
5181static void ext4_wait_for_tail_page_commit(struct inode *inode)
5182{
5183	struct page *page;
5184	unsigned offset;
5185	journal_t *journal = EXT4_SB(inode->i_sb)->s_journal;
5186	tid_t commit_tid = 0;
5187	int ret;
5188
5189	offset = inode->i_size & (PAGE_SIZE - 1);
5190	/*
5191	 * If the page is fully truncated, we don't need to wait for any commit
5192	 * (and we even should not as __ext4_journalled_invalidatepage() may
5193	 * strip all buffers from the page but keep the page dirty which can then
5194	 * confuse e.g. concurrent ext4_writepage() seeing dirty page without
5195	 * buffers). Also we don't need to wait for any commit if all buffers in
5196	 * the page remain valid. This is most beneficial for the common case of
5197	 * blocksize == PAGESIZE.
5198	 */
5199	if (!offset || offset > (PAGE_SIZE - i_blocksize(inode)))
5200		return;
5201	while (1) {
5202		page = find_lock_page(inode->i_mapping,
5203				      inode->i_size >> PAGE_SHIFT);
5204		if (!page)
5205			return;
5206		ret = __ext4_journalled_invalidatepage(page, offset,
5207						PAGE_SIZE - offset);
5208		unlock_page(page);
5209		put_page(page);
5210		if (ret != -EBUSY)
5211			return;
5212		commit_tid = 0;
5213		read_lock(&journal->j_state_lock);
5214		if (journal->j_committing_transaction)
5215			commit_tid = journal->j_committing_transaction->t_tid;
5216		read_unlock(&journal->j_state_lock);
5217		if (commit_tid)
5218			jbd2_log_wait_commit(journal, commit_tid);
5219	}
5220}
5221
5222/*
5223 * ext4_setattr()
5224 *
5225 * Called from notify_change.
5226 *
5227 * We want to trap VFS attempts to truncate the file as soon as
5228 * possible.  In particular, we want to make sure that when the VFS
5229 * shrinks i_size, we put the inode on the orphan list and modify
5230 * i_disksize immediately, so that during the subsequent flushing of
5231 * dirty pages and freeing of disk blocks, we can guarantee that any
5232 * commit will leave the blocks being flushed in an unused state on
5233 * disk.  (On recovery, the inode will get truncated and the blocks will
5234 * be freed, so we have a strong guarantee that no future commit will
5235 * leave these blocks visible to the user.)
5236 *
5237 * Another thing we have to assure is that if we are in ordered mode
5238 * and inode is still attached to the committing transaction, we must
5239 * we start writeout of all the dirty pages which are being truncated.
5240 * This way we are sure that all the data written in the previous
5241 * transaction are already on disk (truncate waits for pages under
5242 * writeback).
5243 *
5244 * Called with inode->i_mutex down.
5245 */
5246int ext4_setattr(struct dentry *dentry, struct iattr *attr)
 
5247{
5248	struct inode *inode = d_inode(dentry);
5249	int error, rc = 0;
5250	int orphan = 0;
5251	const unsigned int ia_valid = attr->ia_valid;
 
5252
5253	if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb))))
5254		return -EIO;
5255
5256	if (unlikely(IS_IMMUTABLE(inode)))
5257		return -EPERM;
5258
5259	if (unlikely(IS_APPEND(inode) &&
5260		     (ia_valid & (ATTR_MODE | ATTR_UID |
5261				  ATTR_GID | ATTR_TIMES_SET))))
5262		return -EPERM;
5263
5264	error = setattr_prepare(dentry, attr);
5265	if (error)
5266		return error;
5267
5268	error = fscrypt_prepare_setattr(dentry, attr);
5269	if (error)
5270		return error;
5271
5272	error = fsverity_prepare_setattr(dentry, attr);
5273	if (error)
5274		return error;
5275
5276	if (is_quota_modification(inode, attr)) {
5277		error = dquot_initialize(inode);
5278		if (error)
5279			return error;
5280	}
5281	if ((ia_valid & ATTR_UID && !uid_eq(attr->ia_uid, inode->i_uid)) ||
5282	    (ia_valid & ATTR_GID && !gid_eq(attr->ia_gid, inode->i_gid))) {
 
5283		handle_t *handle;
5284
5285		/* (user+group)*(old+new) structure, inode write (sb,
5286		 * inode block, ? - but truncate inode update has it) */
5287		handle = ext4_journal_start(inode, EXT4_HT_QUOTA,
5288			(EXT4_MAXQUOTAS_INIT_BLOCKS(inode->i_sb) +
5289			 EXT4_MAXQUOTAS_DEL_BLOCKS(inode->i_sb)) + 3);
5290		if (IS_ERR(handle)) {
5291			error = PTR_ERR(handle);
5292			goto err_out;
5293		}
5294
5295		/* dquot_transfer() calls back ext4_get_inode_usage() which
5296		 * counts xattr inode references.
5297		 */
5298		down_read(&EXT4_I(inode)->xattr_sem);
5299		error = dquot_transfer(inode, attr);
5300		up_read(&EXT4_I(inode)->xattr_sem);
5301
5302		if (error) {
5303			ext4_journal_stop(handle);
5304			return error;
5305		}
5306		/* Update corresponding info in inode so that everything is in
5307		 * one transaction */
5308		if (attr->ia_valid & ATTR_UID)
5309			inode->i_uid = attr->ia_uid;
5310		if (attr->ia_valid & ATTR_GID)
5311			inode->i_gid = attr->ia_gid;
5312		error = ext4_mark_inode_dirty(handle, inode);
5313		ext4_journal_stop(handle);
5314		if (unlikely(error))
5315			return error;
 
5316	}
5317
5318	if (attr->ia_valid & ATTR_SIZE) {
5319		handle_t *handle;
5320		loff_t oldsize = inode->i_size;
 
5321		int shrink = (attr->ia_size < inode->i_size);
5322
5323		if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) {
5324			struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
5325
5326			if (attr->ia_size > sbi->s_bitmap_maxbytes)
5327				return -EFBIG;
 
5328		}
5329		if (!S_ISREG(inode->i_mode))
5330			return -EINVAL;
 
5331
5332		if (IS_I_VERSION(inode) && attr->ia_size != inode->i_size)
5333			inode_inc_iversion(inode);
5334
5335		if (shrink) {
5336			if (ext4_should_order_data(inode)) {
5337				error = ext4_begin_ordered_truncate(inode,
5338							    attr->ia_size);
5339				if (error)
5340					goto err_out;
5341			}
5342			/*
5343			 * Blocks are going to be removed from the inode. Wait
5344			 * for dio in flight.
5345			 */
5346			inode_dio_wait(inode);
5347		}
5348
5349		down_write(&EXT4_I(inode)->i_mmap_sem);
5350
5351		rc = ext4_break_layouts(inode);
5352		if (rc) {
5353			up_write(&EXT4_I(inode)->i_mmap_sem);
5354			return rc;
5355		}
5356
5357		if (attr->ia_size != inode->i_size) {
5358			handle = ext4_journal_start(inode, EXT4_HT_INODE, 3);
5359			if (IS_ERR(handle)) {
5360				error = PTR_ERR(handle);
5361				goto out_mmap_sem;
5362			}
5363			if (ext4_handle_valid(handle) && shrink) {
5364				error = ext4_orphan_add(handle, inode);
5365				orphan = 1;
5366			}
5367			/*
5368			 * Update c/mtime on truncate up, ext4_truncate() will
5369			 * update c/mtime in shrink case below
5370			 */
5371			if (!shrink) {
5372				inode->i_mtime = current_time(inode);
5373				inode->i_ctime = inode->i_mtime;
5374			}
 
 
 
 
 
 
 
 
 
 
 
 
 
 
5375			down_write(&EXT4_I(inode)->i_data_sem);
 
5376			EXT4_I(inode)->i_disksize = attr->ia_size;
5377			rc = ext4_mark_inode_dirty(handle, inode);
5378			if (!error)
5379				error = rc;
5380			/*
5381			 * We have to update i_size under i_data_sem together
5382			 * with i_disksize to avoid races with writeback code
5383			 * running ext4_wb_update_i_disksize().
5384			 */
5385			if (!error)
5386				i_size_write(inode, attr->ia_size);
 
 
5387			up_write(&EXT4_I(inode)->i_data_sem);
5388			ext4_journal_stop(handle);
5389			if (error)
5390				goto out_mmap_sem;
5391			if (!shrink) {
5392				pagecache_isize_extended(inode, oldsize,
5393							 inode->i_size);
5394			} else if (ext4_should_journal_data(inode)) {
5395				ext4_wait_for_tail_page_commit(inode);
5396			}
5397		}
5398
5399		/*
5400		 * Truncate pagecache after we've waited for commit
5401		 * in data=journal mode to make pages freeable.
5402		 */
5403		truncate_pagecache(inode, inode->i_size);
5404		/*
5405		 * Call ext4_truncate() even if i_size didn't change to
5406		 * truncate possible preallocated blocks.
5407		 */
5408		if (attr->ia_size <= oldsize) {
5409			rc = ext4_truncate(inode);
5410			if (rc)
5411				error = rc;
5412		}
5413out_mmap_sem:
5414		up_write(&EXT4_I(inode)->i_mmap_sem);
5415	}
5416
5417	if (!error) {
5418		setattr_copy(inode, attr);
 
 
5419		mark_inode_dirty(inode);
5420	}
5421
5422	/*
5423	 * If the call to ext4_truncate failed to get a transaction handle at
5424	 * all, we need to clean up the in-core orphan list manually.
5425	 */
5426	if (orphan && inode->i_nlink)
5427		ext4_orphan_del(NULL, inode);
5428
5429	if (!error && (ia_valid & ATTR_MODE))
5430		rc = posix_acl_chmod(inode, inode->i_mode);
5431
5432err_out:
5433	ext4_std_error(inode->i_sb, error);
 
5434	if (!error)
5435		error = rc;
5436	return error;
5437}
5438
5439int ext4_getattr(const struct path *path, struct kstat *stat,
5440		 u32 request_mask, unsigned int query_flags)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
5441{
5442	struct inode *inode = d_inode(path->dentry);
5443	struct ext4_inode *raw_inode;
5444	struct ext4_inode_info *ei = EXT4_I(inode);
5445	unsigned int flags;
5446
5447	if ((request_mask & STATX_BTIME) &&
5448	    EXT4_FITS_IN_INODE(raw_inode, ei, i_crtime)) {
5449		stat->result_mask |= STATX_BTIME;
5450		stat->btime.tv_sec = ei->i_crtime.tv_sec;
5451		stat->btime.tv_nsec = ei->i_crtime.tv_nsec;
5452	}
5453
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
5454	flags = ei->i_flags & EXT4_FL_USER_VISIBLE;
5455	if (flags & EXT4_APPEND_FL)
5456		stat->attributes |= STATX_ATTR_APPEND;
5457	if (flags & EXT4_COMPR_FL)
5458		stat->attributes |= STATX_ATTR_COMPRESSED;
5459	if (flags & EXT4_ENCRYPT_FL)
5460		stat->attributes |= STATX_ATTR_ENCRYPTED;
5461	if (flags & EXT4_IMMUTABLE_FL)
5462		stat->attributes |= STATX_ATTR_IMMUTABLE;
5463	if (flags & EXT4_NODUMP_FL)
5464		stat->attributes |= STATX_ATTR_NODUMP;
5465	if (flags & EXT4_VERITY_FL)
5466		stat->attributes |= STATX_ATTR_VERITY;
5467
5468	stat->attributes_mask |= (STATX_ATTR_APPEND |
5469				  STATX_ATTR_COMPRESSED |
5470				  STATX_ATTR_ENCRYPTED |
5471				  STATX_ATTR_IMMUTABLE |
5472				  STATX_ATTR_NODUMP |
5473				  STATX_ATTR_VERITY);
5474
5475	generic_fillattr(inode, stat);
5476	return 0;
5477}
5478
5479int ext4_file_getattr(const struct path *path, struct kstat *stat,
 
5480		      u32 request_mask, unsigned int query_flags)
5481{
5482	struct inode *inode = d_inode(path->dentry);
5483	u64 delalloc_blocks;
5484
5485	ext4_getattr(path, stat, request_mask, query_flags);
5486
5487	/*
5488	 * If there is inline data in the inode, the inode will normally not
5489	 * have data blocks allocated (it may have an external xattr block).
5490	 * Report at least one sector for such files, so tools like tar, rsync,
5491	 * others don't incorrectly think the file is completely sparse.
5492	 */
5493	if (unlikely(ext4_has_inline_data(inode)))
5494		stat->blocks += (stat->size + 511) >> 9;
5495
5496	/*
5497	 * We can't update i_blocks if the block allocation is delayed
5498	 * otherwise in the case of system crash before the real block
5499	 * allocation is done, we will have i_blocks inconsistent with
5500	 * on-disk file blocks.
5501	 * We always keep i_blocks updated together with real
5502	 * allocation. But to not confuse with user, stat
5503	 * will return the blocks that include the delayed allocation
5504	 * blocks for this file.
5505	 */
5506	delalloc_blocks = EXT4_C2B(EXT4_SB(inode->i_sb),
5507				   EXT4_I(inode)->i_reserved_data_blocks);
5508	stat->blocks += delalloc_blocks << (inode->i_sb->s_blocksize_bits - 9);
5509	return 0;
5510}
5511
5512static int ext4_index_trans_blocks(struct inode *inode, int lblocks,
5513				   int pextents)
5514{
5515	if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
5516		return ext4_ind_trans_blocks(inode, lblocks);
5517	return ext4_ext_index_trans_blocks(inode, pextents);
5518}
5519
5520/*
5521 * Account for index blocks, block groups bitmaps and block group
5522 * descriptor blocks if modify datablocks and index blocks
5523 * worse case, the indexs blocks spread over different block groups
5524 *
5525 * If datablocks are discontiguous, they are possible to spread over
5526 * different block groups too. If they are contiguous, with flexbg,
5527 * they could still across block group boundary.
5528 *
5529 * Also account for superblock, inode, quota and xattr blocks
5530 */
5531static int ext4_meta_trans_blocks(struct inode *inode, int lblocks,
5532				  int pextents)
5533{
5534	ext4_group_t groups, ngroups = ext4_get_groups_count(inode->i_sb);
5535	int gdpblocks;
5536	int idxblocks;
5537	int ret = 0;
5538
5539	/*
5540	 * How many index blocks need to touch to map @lblocks logical blocks
5541	 * to @pextents physical extents?
5542	 */
5543	idxblocks = ext4_index_trans_blocks(inode, lblocks, pextents);
5544
5545	ret = idxblocks;
5546
5547	/*
5548	 * Now let's see how many group bitmaps and group descriptors need
5549	 * to account
5550	 */
5551	groups = idxblocks + pextents;
5552	gdpblocks = groups;
5553	if (groups > ngroups)
5554		groups = ngroups;
5555	if (groups > EXT4_SB(inode->i_sb)->s_gdb_count)
5556		gdpblocks = EXT4_SB(inode->i_sb)->s_gdb_count;
5557
5558	/* bitmaps and block group descriptor blocks */
5559	ret += groups + gdpblocks;
5560
5561	/* Blocks for super block, inode, quota and xattr blocks */
5562	ret += EXT4_META_TRANS_BLOCKS(inode->i_sb);
5563
5564	return ret;
5565}
5566
5567/*
5568 * Calculate the total number of credits to reserve to fit
5569 * the modification of a single pages into a single transaction,
5570 * which may include multiple chunks of block allocations.
5571 *
5572 * This could be called via ext4_write_begin()
5573 *
5574 * We need to consider the worse case, when
5575 * one new block per extent.
5576 */
5577int ext4_writepage_trans_blocks(struct inode *inode)
5578{
5579	int bpp = ext4_journal_blocks_per_page(inode);
5580	int ret;
5581
5582	ret = ext4_meta_trans_blocks(inode, bpp, bpp);
5583
5584	/* Account for data blocks for journalled mode */
5585	if (ext4_should_journal_data(inode))
5586		ret += bpp;
5587	return ret;
5588}
5589
5590/*
5591 * Calculate the journal credits for a chunk of data modification.
5592 *
5593 * This is called from DIO, fallocate or whoever calling
5594 * ext4_map_blocks() to map/allocate a chunk of contiguous disk blocks.
5595 *
5596 * journal buffers for data blocks are not included here, as DIO
5597 * and fallocate do no need to journal data buffers.
5598 */
5599int ext4_chunk_trans_blocks(struct inode *inode, int nrblocks)
5600{
5601	return ext4_meta_trans_blocks(inode, nrblocks, 1);
5602}
5603
5604/*
5605 * The caller must have previously called ext4_reserve_inode_write().
5606 * Give this, we know that the caller already has write access to iloc->bh.
5607 */
5608int ext4_mark_iloc_dirty(handle_t *handle,
5609			 struct inode *inode, struct ext4_iloc *iloc)
5610{
5611	int err = 0;
5612
5613	if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb)))) {
5614		put_bh(iloc->bh);
5615		return -EIO;
5616	}
5617	if (IS_I_VERSION(inode))
5618		inode_inc_iversion(inode);
5619
5620	/* the do_update_inode consumes one bh->b_count */
5621	get_bh(iloc->bh);
5622
5623	/* ext4_do_update_inode() does jbd2_journal_dirty_metadata */
5624	err = ext4_do_update_inode(handle, inode, iloc);
5625	put_bh(iloc->bh);
5626	return err;
5627}
5628
5629/*
5630 * On success, We end up with an outstanding reference count against
5631 * iloc->bh.  This _must_ be cleaned up later.
5632 */
5633
5634int
5635ext4_reserve_inode_write(handle_t *handle, struct inode *inode,
5636			 struct ext4_iloc *iloc)
5637{
5638	int err;
5639
5640	if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb))))
5641		return -EIO;
5642
5643	err = ext4_get_inode_loc(inode, iloc);
5644	if (!err) {
5645		BUFFER_TRACE(iloc->bh, "get_write_access");
5646		err = ext4_journal_get_write_access(handle, iloc->bh);
 
5647		if (err) {
5648			brelse(iloc->bh);
5649			iloc->bh = NULL;
5650		}
5651	}
5652	ext4_std_error(inode->i_sb, err);
5653	return err;
5654}
5655
5656static int __ext4_expand_extra_isize(struct inode *inode,
5657				     unsigned int new_extra_isize,
5658				     struct ext4_iloc *iloc,
5659				     handle_t *handle, int *no_expand)
5660{
5661	struct ext4_inode *raw_inode;
5662	struct ext4_xattr_ibody_header *header;
5663	unsigned int inode_size = EXT4_INODE_SIZE(inode->i_sb);
5664	struct ext4_inode_info *ei = EXT4_I(inode);
5665	int error;
5666
5667	/* this was checked at iget time, but double check for good measure */
5668	if ((EXT4_GOOD_OLD_INODE_SIZE + ei->i_extra_isize > inode_size) ||
5669	    (ei->i_extra_isize & 3)) {
5670		EXT4_ERROR_INODE(inode, "bad extra_isize %u (inode size %u)",
5671				 ei->i_extra_isize,
5672				 EXT4_INODE_SIZE(inode->i_sb));
5673		return -EFSCORRUPTED;
5674	}
5675	if ((new_extra_isize < ei->i_extra_isize) ||
5676	    (new_extra_isize < 4) ||
5677	    (new_extra_isize > inode_size - EXT4_GOOD_OLD_INODE_SIZE))
5678		return -EINVAL;	/* Should never happen */
5679
5680	raw_inode = ext4_raw_inode(iloc);
5681
5682	header = IHDR(inode, raw_inode);
5683
5684	/* No extended attributes present */
5685	if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR) ||
5686	    header->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC)) {
5687		memset((void *)raw_inode + EXT4_GOOD_OLD_INODE_SIZE +
5688		       EXT4_I(inode)->i_extra_isize, 0,
5689		       new_extra_isize - EXT4_I(inode)->i_extra_isize);
5690		EXT4_I(inode)->i_extra_isize = new_extra_isize;
5691		return 0;
5692	}
5693
 
 
 
 
 
 
 
 
5694	/* try to expand with EAs present */
5695	error = ext4_expand_extra_isize_ea(inode, new_extra_isize,
5696					   raw_inode, handle);
5697	if (error) {
5698		/*
5699		 * Inode size expansion failed; don't try again
5700		 */
5701		*no_expand = 1;
5702	}
5703
5704	return error;
5705}
5706
5707/*
5708 * Expand an inode by new_extra_isize bytes.
5709 * Returns 0 on success or negative error number on failure.
5710 */
5711static int ext4_try_to_expand_extra_isize(struct inode *inode,
5712					  unsigned int new_extra_isize,
5713					  struct ext4_iloc iloc,
5714					  handle_t *handle)
5715{
5716	int no_expand;
5717	int error;
5718
5719	if (ext4_test_inode_state(inode, EXT4_STATE_NO_EXPAND))
5720		return -EOVERFLOW;
5721
5722	/*
5723	 * In nojournal mode, we can immediately attempt to expand
5724	 * the inode.  When journaled, we first need to obtain extra
5725	 * buffer credits since we may write into the EA block
5726	 * with this same handle. If journal_extend fails, then it will
5727	 * only result in a minor loss of functionality for that inode.
5728	 * If this is felt to be critical, then e2fsck should be run to
5729	 * force a large enough s_min_extra_isize.
5730	 */
5731	if (ext4_journal_extend(handle,
5732				EXT4_DATA_TRANS_BLOCKS(inode->i_sb), 0) != 0)
5733		return -ENOSPC;
5734
5735	if (ext4_write_trylock_xattr(inode, &no_expand) == 0)
5736		return -EBUSY;
5737
5738	error = __ext4_expand_extra_isize(inode, new_extra_isize, &iloc,
5739					  handle, &no_expand);
5740	ext4_write_unlock_xattr(inode, &no_expand);
5741
5742	return error;
5743}
5744
5745int ext4_expand_extra_isize(struct inode *inode,
5746			    unsigned int new_extra_isize,
5747			    struct ext4_iloc *iloc)
5748{
5749	handle_t *handle;
5750	int no_expand;
5751	int error, rc;
5752
5753	if (ext4_test_inode_state(inode, EXT4_STATE_NO_EXPAND)) {
5754		brelse(iloc->bh);
5755		return -EOVERFLOW;
5756	}
5757
5758	handle = ext4_journal_start(inode, EXT4_HT_INODE,
5759				    EXT4_DATA_TRANS_BLOCKS(inode->i_sb));
5760	if (IS_ERR(handle)) {
5761		error = PTR_ERR(handle);
5762		brelse(iloc->bh);
5763		return error;
5764	}
5765
5766	ext4_write_lock_xattr(inode, &no_expand);
5767
5768	BUFFER_TRACE(iloc->bh, "get_write_access");
5769	error = ext4_journal_get_write_access(handle, iloc->bh);
 
5770	if (error) {
5771		brelse(iloc->bh);
5772		goto out_unlock;
5773	}
5774
5775	error = __ext4_expand_extra_isize(inode, new_extra_isize, iloc,
5776					  handle, &no_expand);
5777
5778	rc = ext4_mark_iloc_dirty(handle, inode, iloc);
5779	if (!error)
5780		error = rc;
5781
5782out_unlock:
5783	ext4_write_unlock_xattr(inode, &no_expand);
5784	ext4_journal_stop(handle);
5785	return error;
5786}
5787
5788/*
5789 * What we do here is to mark the in-core inode as clean with respect to inode
5790 * dirtiness (it may still be data-dirty).
5791 * This means that the in-core inode may be reaped by prune_icache
5792 * without having to perform any I/O.  This is a very good thing,
5793 * because *any* task may call prune_icache - even ones which
5794 * have a transaction open against a different journal.
5795 *
5796 * Is this cheating?  Not really.  Sure, we haven't written the
5797 * inode out, but prune_icache isn't a user-visible syncing function.
5798 * Whenever the user wants stuff synced (sys_sync, sys_msync, sys_fsync)
5799 * we start and wait on commits.
5800 */
5801int __ext4_mark_inode_dirty(handle_t *handle, struct inode *inode,
5802				const char *func, unsigned int line)
5803{
5804	struct ext4_iloc iloc;
5805	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
5806	int err;
5807
5808	might_sleep();
5809	trace_ext4_mark_inode_dirty(inode, _RET_IP_);
5810	err = ext4_reserve_inode_write(handle, inode, &iloc);
5811	if (err)
5812		goto out;
5813
5814	if (EXT4_I(inode)->i_extra_isize < sbi->s_want_extra_isize)
5815		ext4_try_to_expand_extra_isize(inode, sbi->s_want_extra_isize,
5816					       iloc, handle);
5817
5818	err = ext4_mark_iloc_dirty(handle, inode, &iloc);
5819out:
5820	if (unlikely(err))
5821		ext4_error_inode_err(inode, func, line, 0, err,
5822					"mark_inode_dirty error");
5823	return err;
5824}
5825
5826/*
5827 * ext4_dirty_inode() is called from __mark_inode_dirty()
5828 *
5829 * We're really interested in the case where a file is being extended.
5830 * i_size has been changed by generic_commit_write() and we thus need
5831 * to include the updated inode in the current transaction.
5832 *
5833 * Also, dquot_alloc_block() will always dirty the inode when blocks
5834 * are allocated to the file.
5835 *
5836 * If the inode is marked synchronous, we don't honour that here - doing
5837 * so would cause a commit on atime updates, which we don't bother doing.
5838 * We handle synchronous inodes at the highest possible level.
5839 *
5840 * If only the I_DIRTY_TIME flag is set, we can skip everything.  If
5841 * I_DIRTY_TIME and I_DIRTY_SYNC is set, the only inode fields we need
5842 * to copy into the on-disk inode structure are the timestamp files.
5843 */
5844void ext4_dirty_inode(struct inode *inode, int flags)
5845{
5846	handle_t *handle;
5847
5848	if (flags == I_DIRTY_TIME)
5849		return;
5850	handle = ext4_journal_start(inode, EXT4_HT_INODE, 2);
5851	if (IS_ERR(handle))
5852		goto out;
5853
5854	ext4_mark_inode_dirty(handle, inode);
5855
5856	ext4_journal_stop(handle);
5857out:
5858	return;
5859}
5860
5861int ext4_change_inode_journal_flag(struct inode *inode, int val)
5862{
5863	journal_t *journal;
5864	handle_t *handle;
5865	int err;
5866	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
5867
5868	/*
5869	 * We have to be very careful here: changing a data block's
5870	 * journaling status dynamically is dangerous.  If we write a
5871	 * data block to the journal, change the status and then delete
5872	 * that block, we risk forgetting to revoke the old log record
5873	 * from the journal and so a subsequent replay can corrupt data.
5874	 * So, first we make sure that the journal is empty and that
5875	 * nobody is changing anything.
5876	 */
5877
5878	journal = EXT4_JOURNAL(inode);
5879	if (!journal)
5880		return 0;
5881	if (is_journal_aborted(journal))
5882		return -EROFS;
5883
5884	/* Wait for all existing dio workers */
5885	inode_dio_wait(inode);
5886
5887	/*
5888	 * Before flushing the journal and switching inode's aops, we have
5889	 * to flush all dirty data the inode has. There can be outstanding
5890	 * delayed allocations, there can be unwritten extents created by
5891	 * fallocate or buffered writes in dioread_nolock mode covered by
5892	 * dirty data which can be converted only after flushing the dirty
5893	 * data (and journalled aops don't know how to handle these cases).
5894	 */
5895	if (val) {
5896		down_write(&EXT4_I(inode)->i_mmap_sem);
5897		err = filemap_write_and_wait(inode->i_mapping);
5898		if (err < 0) {
5899			up_write(&EXT4_I(inode)->i_mmap_sem);
5900			return err;
5901		}
5902	}
5903
5904	percpu_down_write(&sbi->s_writepages_rwsem);
5905	jbd2_journal_lock_updates(journal);
5906
5907	/*
5908	 * OK, there are no updates running now, and all cached data is
5909	 * synced to disk.  We are now in a completely consistent state
5910	 * which doesn't have anything in the journal, and we know that
5911	 * no filesystem updates are running, so it is safe to modify
5912	 * the inode's in-core data-journaling state flag now.
5913	 */
5914
5915	if (val)
5916		ext4_set_inode_flag(inode, EXT4_INODE_JOURNAL_DATA);
5917	else {
5918		err = jbd2_journal_flush(journal);
5919		if (err < 0) {
5920			jbd2_journal_unlock_updates(journal);
5921			percpu_up_write(&sbi->s_writepages_rwsem);
5922			return err;
5923		}
5924		ext4_clear_inode_flag(inode, EXT4_INODE_JOURNAL_DATA);
5925	}
5926	ext4_set_aops(inode);
5927
5928	jbd2_journal_unlock_updates(journal);
5929	percpu_up_write(&sbi->s_writepages_rwsem);
5930
5931	if (val)
5932		up_write(&EXT4_I(inode)->i_mmap_sem);
5933
5934	/* Finally we can mark the inode as dirty. */
5935
5936	handle = ext4_journal_start(inode, EXT4_HT_INODE, 1);
5937	if (IS_ERR(handle))
5938		return PTR_ERR(handle);
5939
 
 
5940	err = ext4_mark_inode_dirty(handle, inode);
5941	ext4_handle_sync(handle);
5942	ext4_journal_stop(handle);
5943	ext4_std_error(inode->i_sb, err);
5944
5945	return err;
5946}
5947
5948static int ext4_bh_unmapped(handle_t *handle, struct buffer_head *bh)
 
5949{
5950	return !buffer_mapped(bh);
5951}
5952
5953vm_fault_t ext4_page_mkwrite(struct vm_fault *vmf)
5954{
5955	struct vm_area_struct *vma = vmf->vma;
5956	struct page *page = vmf->page;
5957	loff_t size;
5958	unsigned long len;
5959	int err;
5960	vm_fault_t ret;
5961	struct file *file = vma->vm_file;
5962	struct inode *inode = file_inode(file);
5963	struct address_space *mapping = inode->i_mapping;
5964	handle_t *handle;
5965	get_block_t *get_block;
5966	int retries = 0;
5967
5968	if (unlikely(IS_IMMUTABLE(inode)))
5969		return VM_FAULT_SIGBUS;
5970
5971	sb_start_pagefault(inode->i_sb);
5972	file_update_time(vma->vm_file);
5973
5974	down_read(&EXT4_I(inode)->i_mmap_sem);
5975
5976	err = ext4_convert_inline_data(inode);
5977	if (err)
5978		goto out_ret;
5979
 
 
 
 
 
 
 
 
 
5980	/* Delalloc case is easy... */
5981	if (test_opt(inode->i_sb, DELALLOC) &&
5982	    !ext4_should_journal_data(inode) &&
5983	    !ext4_nonda_switch(inode->i_sb)) {
5984		do {
5985			err = block_page_mkwrite(vma, vmf,
5986						   ext4_da_get_block_prep);
5987		} while (err == -ENOSPC &&
5988		       ext4_should_retry_alloc(inode->i_sb, &retries));
5989		goto out_ret;
5990	}
5991
5992	lock_page(page);
5993	size = i_size_read(inode);
5994	/* Page got truncated from under us? */
5995	if (page->mapping != mapping || page_offset(page) > size) {
5996		unlock_page(page);
5997		ret = VM_FAULT_NOPAGE;
5998		goto out;
5999	}
6000
6001	if (page->index == size >> PAGE_SHIFT)
6002		len = size & ~PAGE_MASK;
6003	else
6004		len = PAGE_SIZE;
6005	/*
6006	 * Return if we have all the buffers mapped. This avoids the need to do
6007	 * journal_start/journal_stop which can block and take a long time
 
 
 
6008	 */
6009	if (page_has_buffers(page)) {
6010		if (!ext4_walk_page_buffers(NULL, page_buffers(page),
6011					    0, len, NULL,
6012					    ext4_bh_unmapped)) {
6013			/* Wait so that we don't change page under IO */
6014			wait_for_stable_page(page);
6015			ret = VM_FAULT_LOCKED;
6016			goto out;
6017		}
6018	}
6019	unlock_page(page);
6020	/* OK, we need to fill the hole... */
6021	if (ext4_should_dioread_nolock(inode))
6022		get_block = ext4_get_block_unwritten;
6023	else
6024		get_block = ext4_get_block;
6025retry_alloc:
6026	handle = ext4_journal_start(inode, EXT4_HT_WRITE_PAGE,
6027				    ext4_writepage_trans_blocks(inode));
6028	if (IS_ERR(handle)) {
6029		ret = VM_FAULT_SIGBUS;
6030		goto out;
6031	}
6032	err = block_page_mkwrite(vma, vmf, get_block);
6033	if (!err && ext4_should_journal_data(inode)) {
6034		if (ext4_walk_page_buffers(handle, page_buffers(page), 0,
6035			  PAGE_SIZE, NULL, do_journal_get_write_access)) {
6036			unlock_page(page);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
6037			ret = VM_FAULT_SIGBUS;
6038			ext4_journal_stop(handle);
6039			goto out;
 
 
 
 
 
 
 
 
 
 
 
 
6040		}
6041		ext4_set_inode_state(inode, EXT4_STATE_JDATA);
6042	}
6043	ext4_journal_stop(handle);
6044	if (err == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
6045		goto retry_alloc;
6046out_ret:
6047	ret = block_page_mkwrite_return(err);
6048out:
6049	up_read(&EXT4_I(inode)->i_mmap_sem);
6050	sb_end_pagefault(inode->i_sb);
6051	return ret;
6052}
6053
6054vm_fault_t ext4_filemap_fault(struct vm_fault *vmf)
6055{
6056	struct inode *inode = file_inode(vmf->vma->vm_file);
6057	vm_fault_t ret;
6058
6059	down_read(&EXT4_I(inode)->i_mmap_sem);
6060	ret = filemap_fault(vmf);
6061	up_read(&EXT4_I(inode)->i_mmap_sem);
6062
6063	return ret;
6064}