1/*
   2 *  linux/fs/ext4/inode.c
   3 *
   4 * Copyright (C) 1992, 1993, 1994, 1995
   5 * Remy Card (card@masi.ibp.fr)
   6 * Laboratoire MASI - Institut Blaise Pascal
   7 * Universite Pierre et Marie Curie (Paris VI)
   8 *
   9 *  from
  10 *
  11 *  linux/fs/minix/inode.c
  12 *
  13 *  Copyright (C) 1991, 1992  Linus Torvalds
  14 *
  15 *  64-bit file support on 64-bit platforms by Jakub Jelinek
  16 *	(jj@sunsite.ms.mff.cuni.cz)
  17 *
  18 *  Assorted race fixes, rewrite of ext4_get_block() by Al Viro, 2000
  19 */
  20
  21#include <linux/fs.h>
  22#include <linux/time.h>
 
  23#include <linux/highuid.h>
  24#include <linux/pagemap.h>
  25#include <linux/dax.h>
  26#include <linux/quotaops.h>
  27#include <linux/string.h>
  28#include <linux/buffer_head.h>
  29#include <linux/writeback.h>
  30#include <linux/pagevec.h>
  31#include <linux/mpage.h>
  32#include <linux/namei.h>
  33#include <linux/uio.h>
  34#include <linux/bio.h>
  35#include <linux/workqueue.h>
  36#include <linux/kernel.h>
  37#include <linux/printk.h>
  38#include <linux/slab.h>
 
 
  39#include <linux/bitops.h>
  40
  41#include "ext4_jbd2.h"
  42#include "xattr.h"
  43#include "acl.h"
  44#include "truncate.h"
  45
  46#include <trace/events/ext4.h>
  47
  48#define MPAGE_DA_EXTENT_TAIL 0x01
  49
  50static __u32 ext4_inode_csum(struct inode *inode, struct ext4_inode *raw,
  51			      struct ext4_inode_info *ei)
  52{
  53	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
  54	__u16 csum_lo;
  55	__u16 csum_hi = 0;
  56	__u32 csum;
  57
  58	csum_lo = le16_to_cpu(raw->i_checksum_lo);
  59	raw->i_checksum_lo = 0;
  60	if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE &&
  61	    EXT4_FITS_IN_INODE(raw, ei, i_checksum_hi)) {
  62		csum_hi = le16_to_cpu(raw->i_checksum_hi);
  63		raw->i_checksum_hi = 0;
  64	}
  65
  66	csum = ext4_chksum(sbi, ei->i_csum_seed, (__u8 *)raw,
  67			   EXT4_INODE_SIZE(inode->i_sb));
  68
  69	raw->i_checksum_lo = cpu_to_le16(csum_lo);
  70	if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE &&
  71	    EXT4_FITS_IN_INODE(raw, ei, i_checksum_hi))
  72		raw->i_checksum_hi = cpu_to_le16(csum_hi);
  73
  74	return csum;
  75}
  76
  77static int ext4_inode_csum_verify(struct inode *inode, struct ext4_inode *raw,
  78				  struct ext4_inode_info *ei)
  79{
  80	__u32 provided, calculated;
  81
  82	if (EXT4_SB(inode->i_sb)->s_es->s_creator_os !=
  83	    cpu_to_le32(EXT4_OS_LINUX) ||
  84	    !ext4_has_metadata_csum(inode->i_sb))
 
  85		return 1;
  86
  87	provided = le16_to_cpu(raw->i_checksum_lo);
  88	calculated = ext4_inode_csum(inode, raw, ei);
  89	if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE &&
  90	    EXT4_FITS_IN_INODE(raw, ei, i_checksum_hi))
  91		provided |= ((__u32)le16_to_cpu(raw->i_checksum_hi)) << 16;
  92	else
  93		calculated &= 0xFFFF;
  94
  95	return provided == calculated;
  96}
  97
  98static void ext4_inode_csum_set(struct inode *inode, struct ext4_inode *raw,
  99				struct ext4_inode_info *ei)
 100{
 101	__u32 csum;
 102
 103	if (EXT4_SB(inode->i_sb)->s_es->s_creator_os !=
 104	    cpu_to_le32(EXT4_OS_LINUX) ||
 105	    !ext4_has_metadata_csum(inode->i_sb))
 
 106		return;
 107
 108	csum = ext4_inode_csum(inode, raw, ei);
 109	raw->i_checksum_lo = cpu_to_le16(csum & 0xFFFF);
 110	if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE &&
 111	    EXT4_FITS_IN_INODE(raw, ei, i_checksum_hi))
 112		raw->i_checksum_hi = cpu_to_le16(csum >> 16);
 113}
 114
 115static inline int ext4_begin_ordered_truncate(struct inode *inode,
 116					      loff_t new_size)
 117{
 118	trace_ext4_begin_ordered_truncate(inode, new_size);
 119	/*
 120	 * If jinode is zero, then we never opened the file for
 121	 * writing, so there's no need to call
 122	 * jbd2_journal_begin_ordered_truncate() since there's no
 123	 * outstanding writes we need to flush.
 124	 */
 125	if (!EXT4_I(inode)->jinode)
 126		return 0;
 127	return jbd2_journal_begin_ordered_truncate(EXT4_JOURNAL(inode),
 128						   EXT4_I(inode)->jinode,
 129						   new_size);
 130}
 131
 132static void ext4_invalidatepage(struct page *page, unsigned int offset,
 133				unsigned int length);
 134static int __ext4_journalled_writepage(struct page *page, unsigned int len);
 135static int ext4_bh_delay_or_unwritten(handle_t *handle, struct buffer_head *bh);
 136static int ext4_meta_trans_blocks(struct inode *inode, int lblocks,
 137				  int pextents);
 138
 139/*
 140 * Test whether an inode is a fast symlink.
 141 */
 142int ext4_inode_is_fast_symlink(struct inode *inode)
 143{
 144        int ea_blocks = EXT4_I(inode)->i_file_acl ?
 145		EXT4_CLUSTER_SIZE(inode->i_sb) >> 9 : 0;
 146
 147	if (ext4_has_inline_data(inode))
 148		return 0;
 149
 150	return (S_ISLNK(inode->i_mode) && inode->i_blocks - ea_blocks == 0);
 151}
 152
 153/*
 154 * Restart the transaction associated with *handle.  This does a commit,
 155 * so before we call here everything must be consistently dirtied against
 156 * this transaction.
 157 */
 158int ext4_truncate_restart_trans(handle_t *handle, struct inode *inode,
 159				 int nblocks)
 160{
 161	int ret;
 162
 163	/*
 164	 * Drop i_data_sem to avoid deadlock with ext4_map_blocks.  At this
 165	 * moment, get_block can be called only for blocks inside i_size since
 166	 * page cache has been already dropped and writes are blocked by
 167	 * i_mutex. So we can safely drop the i_data_sem here.
 168	 */
 169	BUG_ON(EXT4_JOURNAL(inode) == NULL);
 170	jbd_debug(2, "restarting handle %p\n", handle);
 171	up_write(&EXT4_I(inode)->i_data_sem);
 172	ret = ext4_journal_restart(handle, nblocks);
 173	down_write(&EXT4_I(inode)->i_data_sem);
 174	ext4_discard_preallocations(inode);
 175
 176	return ret;
 177}
 178
 179/*
 180 * Called at the last iput() if i_nlink is zero.
 181 */
 182void ext4_evict_inode(struct inode *inode)
 183{
 184	handle_t *handle;
 185	int err;
 186
 187	trace_ext4_evict_inode(inode);
 188
 189	if (inode->i_nlink) {
 190		/*
 191		 * When journalling data dirty buffers are tracked only in the
 192		 * journal. So although mm thinks everything is clean and
 193		 * ready for reaping the inode might still have some pages to
 194		 * write in the running transaction or waiting to be
 195		 * checkpointed. Thus calling jbd2_journal_invalidatepage()
 196		 * (via truncate_inode_pages()) to discard these buffers can
 197		 * cause data loss. Also even if we did not discard these
 198		 * buffers, we would have no way to find them after the inode
 199		 * is reaped and thus user could see stale data if he tries to
 200		 * read them before the transaction is checkpointed. So be
 201		 * careful and force everything to disk here... We use
 202		 * ei->i_datasync_tid to store the newest transaction
 203		 * containing inode's data.
 204		 *
 205		 * Note that directories do not have this problem because they
 206		 * don't use page cache.
 207		 */
 208		if (ext4_should_journal_data(inode) &&
 209		    (S_ISLNK(inode->i_mode) || S_ISREG(inode->i_mode)) &&
 210		    inode->i_ino != EXT4_JOURNAL_INO) {
 211			journal_t *journal = EXT4_SB(inode->i_sb)->s_journal;
 212			tid_t commit_tid = EXT4_I(inode)->i_datasync_tid;
 213
 214			jbd2_complete_transaction(journal, commit_tid);
 215			filemap_write_and_wait(&inode->i_data);
 216		}
 217		truncate_inode_pages_final(&inode->i_data);
 218
 
 219		goto no_delete;
 220	}
 221
 222	if (is_bad_inode(inode))
 223		goto no_delete;
 224	dquot_initialize(inode);
 225
 226	if (ext4_should_order_data(inode))
 227		ext4_begin_ordered_truncate(inode, 0);
 228	truncate_inode_pages_final(&inode->i_data);
 229
 
 
 
 
 230	/*
 231	 * Protect us against freezing - iput() caller didn't have to have any
 232	 * protection against it
 233	 */
 234	sb_start_intwrite(inode->i_sb);
 235	handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE,
 236				    ext4_blocks_for_truncate(inode)+3);
 237	if (IS_ERR(handle)) {
 238		ext4_std_error(inode->i_sb, PTR_ERR(handle));
 239		/*
 240		 * If we're going to skip the normal cleanup, we still need to
 241		 * make sure that the in-core orphan linked list is properly
 242		 * cleaned up.
 243		 */
 244		ext4_orphan_del(NULL, inode);
 245		sb_end_intwrite(inode->i_sb);
 246		goto no_delete;
 247	}
 248
 249	if (IS_SYNC(inode))
 250		ext4_handle_sync(handle);
 251	inode->i_size = 0;
 252	err = ext4_mark_inode_dirty(handle, inode);
 253	if (err) {
 254		ext4_warning(inode->i_sb,
 255			     "couldn't mark inode dirty (err %d)", err);
 256		goto stop_handle;
 257	}
 258	if (inode->i_blocks)
 259		ext4_truncate(inode);
 260
 261	/*
 262	 * ext4_ext_truncate() doesn't reserve any slop when it
 263	 * restarts journal transactions; therefore there may not be
 264	 * enough credits left in the handle to remove the inode from
 265	 * the orphan list and set the dtime field.
 266	 */
 267	if (!ext4_handle_has_enough_credits(handle, 3)) {
 268		err = ext4_journal_extend(handle, 3);
 269		if (err > 0)
 270			err = ext4_journal_restart(handle, 3);
 271		if (err != 0) {
 272			ext4_warning(inode->i_sb,
 273				     "couldn't extend journal (err %d)", err);
 274		stop_handle:
 275			ext4_journal_stop(handle);
 276			ext4_orphan_del(NULL, inode);
 277			sb_end_intwrite(inode->i_sb);
 278			goto no_delete;
 279		}
 280	}
 281
 282	/*
 283	 * Kill off the orphan record which ext4_truncate created.
 284	 * AKPM: I think this can be inside the above `if'.
 285	 * Note that ext4_orphan_del() has to be able to cope with the
 286	 * deletion of a non-existent orphan - this is because we don't
 287	 * know if ext4_truncate() actually created an orphan record.
 288	 * (Well, we could do this if we need to, but heck - it works)
 289	 */
 290	ext4_orphan_del(handle, inode);
 291	EXT4_I(inode)->i_dtime	= get_seconds();
 292
 293	/*
 294	 * One subtle ordering requirement: if anything has gone wrong
 295	 * (transaction abort, IO errors, whatever), then we can still
 296	 * do these next steps (the fs will already have been marked as
 297	 * having errors), but we can't free the inode if the mark_dirty
 298	 * fails.
 299	 */
 300	if (ext4_mark_inode_dirty(handle, inode))
 301		/* If that failed, just do the required in-core inode clear. */
 302		ext4_clear_inode(inode);
 303	else
 304		ext4_free_inode(handle, inode);
 305	ext4_journal_stop(handle);
 306	sb_end_intwrite(inode->i_sb);
 307	return;
 308no_delete:
 309	ext4_clear_inode(inode);	/* We must guarantee clearing of inode... */
 310}
 311
 312#ifdef CONFIG_QUOTA
 313qsize_t *ext4_get_reserved_space(struct inode *inode)
 314{
 315	return &EXT4_I(inode)->i_reserved_quota;
 316}
 317#endif
 318
 319/*
 
 
 
 
 
 
 
 
 
 
 
 
 320 * Called with i_data_sem down, which is important since we can call
 321 * ext4_discard_preallocations() from here.
 322 */
 323void ext4_da_update_reserve_space(struct inode *inode,
 324					int used, int quota_claim)
 325{
 326	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
 327	struct ext4_inode_info *ei = EXT4_I(inode);
 328
 329	spin_lock(&ei->i_block_reservation_lock);
 330	trace_ext4_da_update_reserve_space(inode, used, quota_claim);
 331	if (unlikely(used > ei->i_reserved_data_blocks)) {
 332		ext4_warning(inode->i_sb, "%s: ino %lu, used %d "
 333			 "with only %d reserved data blocks",
 334			 __func__, inode->i_ino, used,
 335			 ei->i_reserved_data_blocks);
 336		WARN_ON(1);
 337		used = ei->i_reserved_data_blocks;
 338	}
 339
 
 
 
 
 
 
 
 
 
 
 
 340	/* Update per-inode reservations */
 341	ei->i_reserved_data_blocks -= used;
 342	percpu_counter_sub(&sbi->s_dirtyclusters_counter, used);
 
 
 
 343
 
 
 
 
 
 
 
 
 
 
 
 344	spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
 345
 346	/* Update quota subsystem for data blocks */
 347	if (quota_claim)
 348		dquot_claim_block(inode, EXT4_C2B(sbi, used));
 349	else {
 350		/*
 351		 * We did fallocate with an offset that is already delayed
 352		 * allocated. So on delayed allocated writeback we should
 353		 * not re-claim the quota for fallocated blocks.
 354		 */
 355		dquot_release_reservation_block(inode, EXT4_C2B(sbi, used));
 356	}
 357
 358	/*
 359	 * If we have done all the pending block allocations and if
 360	 * there aren't any writers on the inode, we can discard the
 361	 * inode's preallocations.
 362	 */
 363	if ((ei->i_reserved_data_blocks == 0) &&
 364	    (atomic_read(&inode->i_writecount) == 0))
 365		ext4_discard_preallocations(inode);
 366}
 367
 368static int __check_block_validity(struct inode *inode, const char *func,
 369				unsigned int line,
 370				struct ext4_map_blocks *map)
 371{
 372	if (!ext4_data_block_valid(EXT4_SB(inode->i_sb), map->m_pblk,
 373				   map->m_len)) {
 374		ext4_error_inode(inode, func, line, map->m_pblk,
 375				 "lblock %lu mapped to illegal pblock "
 376				 "(length %d)", (unsigned long) map->m_lblk,
 377				 map->m_len);
 378		return -EFSCORRUPTED;
 379	}
 380	return 0;
 381}
 382
 383int ext4_issue_zeroout(struct inode *inode, ext4_lblk_t lblk, ext4_fsblk_t pblk,
 384		       ext4_lblk_t len)
 385{
 386	int ret;
 387
 388	if (ext4_encrypted_inode(inode))
 389		return ext4_encrypted_zeroout(inode, lblk, pblk, len);
 390
 391	ret = sb_issue_zeroout(inode->i_sb, pblk, len, GFP_NOFS);
 392	if (ret > 0)
 393		ret = 0;
 394
 395	return ret;
 396}
 397
 398#define check_block_validity(inode, map)	\
 399	__check_block_validity((inode), __func__, __LINE__, (map))
 400
 401#ifdef ES_AGGRESSIVE_TEST
 402static void ext4_map_blocks_es_recheck(handle_t *handle,
 403				       struct inode *inode,
 404				       struct ext4_map_blocks *es_map,
 405				       struct ext4_map_blocks *map,
 406				       int flags)
 407{
 408	int retval;
 409
 410	map->m_flags = 0;
 411	/*
 412	 * There is a race window that the result is not the same.
 413	 * e.g. xfstests #223 when dioread_nolock enables.  The reason
 414	 * is that we lookup a block mapping in extent status tree with
 415	 * out taking i_data_sem.  So at the time the unwritten extent
 416	 * could be converted.
 417	 */
 418	down_read(&EXT4_I(inode)->i_data_sem);
 
 419	if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) {
 420		retval = ext4_ext_map_blocks(handle, inode, map, flags &
 421					     EXT4_GET_BLOCKS_KEEP_SIZE);
 422	} else {
 423		retval = ext4_ind_map_blocks(handle, inode, map, flags &
 424					     EXT4_GET_BLOCKS_KEEP_SIZE);
 425	}
 426	up_read((&EXT4_I(inode)->i_data_sem));
 
 
 
 
 
 
 427
 428	/*
 429	 * We don't check m_len because extent will be collpased in status
 430	 * tree.  So the m_len might not equal.
 431	 */
 432	if (es_map->m_lblk != map->m_lblk ||
 433	    es_map->m_flags != map->m_flags ||
 434	    es_map->m_pblk != map->m_pblk) {
 435		printk("ES cache assertion failed for inode: %lu "
 436		       "es_cached ex [%d/%d/%llu/%x] != "
 437		       "found ex [%d/%d/%llu/%x] retval %d flags %x\n",
 438		       inode->i_ino, es_map->m_lblk, es_map->m_len,
 439		       es_map->m_pblk, es_map->m_flags, map->m_lblk,
 440		       map->m_len, map->m_pblk, map->m_flags,
 441		       retval, flags);
 442	}
 443}
 444#endif /* ES_AGGRESSIVE_TEST */
 445
 446/*
 447 * The ext4_map_blocks() function tries to look up the requested blocks,
 448 * and returns if the blocks are already mapped.
 449 *
 450 * Otherwise it takes the write lock of the i_data_sem and allocate blocks
 451 * and store the allocated blocks in the result buffer head and mark it
 452 * mapped.
 453 *
 454 * If file type is extents based, it will call ext4_ext_map_blocks(),
 455 * Otherwise, call with ext4_ind_map_blocks() to handle indirect mapping
 456 * based files
 457 *
 458 * On success, it returns the number of blocks being mapped or allocated.  if
 459 * create==0 and the blocks are pre-allocated and unwritten, the resulting @map
 460 * is marked as unwritten. If the create == 1, it will mark @map as mapped.
 
 461 *
 462 * It returns 0 if plain look up failed (blocks have not been allocated), in
 463 * that case, @map is returned as unmapped but we still do fill map->m_len to
 464 * indicate the length of a hole starting at map->m_lblk.
 465 *
 466 * It returns the error in case of allocation failure.
 467 */
 468int ext4_map_blocks(handle_t *handle, struct inode *inode,
 469		    struct ext4_map_blocks *map, int flags)
 470{
 471	struct extent_status es;
 472	int retval;
 473	int ret = 0;
 474#ifdef ES_AGGRESSIVE_TEST
 475	struct ext4_map_blocks orig_map;
 476
 477	memcpy(&orig_map, map, sizeof(*map));
 478#endif
 479
 480	map->m_flags = 0;
 481	ext_debug("ext4_map_blocks(): inode %lu, flag %d, max_blocks %u,"
 482		  "logical block %lu\n", inode->i_ino, flags, map->m_len,
 483		  (unsigned long) map->m_lblk);
 484
 485	/*
 486	 * ext4_map_blocks returns an int, and m_len is an unsigned int
 487	 */
 488	if (unlikely(map->m_len > INT_MAX))
 489		map->m_len = INT_MAX;
 490
 491	/* We can handle the block number less than EXT_MAX_BLOCKS */
 492	if (unlikely(map->m_lblk >= EXT_MAX_BLOCKS))
 493		return -EFSCORRUPTED;
 494
 495	/* Lookup extent status tree firstly */
 496	if (ext4_es_lookup_extent(inode, map->m_lblk, &es)) {
 
 497		if (ext4_es_is_written(&es) || ext4_es_is_unwritten(&es)) {
 498			map->m_pblk = ext4_es_pblock(&es) +
 499					map->m_lblk - es.es_lblk;
 500			map->m_flags |= ext4_es_is_written(&es) ?
 501					EXT4_MAP_MAPPED : EXT4_MAP_UNWRITTEN;
 502			retval = es.es_len - (map->m_lblk - es.es_lblk);
 503			if (retval > map->m_len)
 504				retval = map->m_len;
 505			map->m_len = retval;
 506		} else if (ext4_es_is_delayed(&es) || ext4_es_is_hole(&es)) {
 507			map->m_pblk = 0;
 508			retval = es.es_len - (map->m_lblk - es.es_lblk);
 509			if (retval > map->m_len)
 510				retval = map->m_len;
 511			map->m_len = retval;
 512			retval = 0;
 513		} else {
 514			BUG_ON(1);
 515		}
 516#ifdef ES_AGGRESSIVE_TEST
 517		ext4_map_blocks_es_recheck(handle, inode, map,
 518					   &orig_map, flags);
 519#endif
 520		goto found;
 521	}
 522
 523	/*
 524	 * Try to see if we can get the block without requesting a new
 525	 * file system block.
 526	 */
 527	down_read(&EXT4_I(inode)->i_data_sem);
 
 528	if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) {
 529		retval = ext4_ext_map_blocks(handle, inode, map, flags &
 530					     EXT4_GET_BLOCKS_KEEP_SIZE);
 531	} else {
 532		retval = ext4_ind_map_blocks(handle, inode, map, flags &
 533					     EXT4_GET_BLOCKS_KEEP_SIZE);
 534	}
 535	if (retval > 0) {
 536		unsigned int status;
 537
 538		if (unlikely(retval != map->m_len)) {
 539			ext4_warning(inode->i_sb,
 540				     "ES len assertion failed for inode "
 541				     "%lu: retval %d != map->m_len %d",
 542				     inode->i_ino, retval, map->m_len);
 543			WARN_ON(1);
 544		}
 545
 546		status = map->m_flags & EXT4_MAP_UNWRITTEN ?
 547				EXTENT_STATUS_UNWRITTEN : EXTENT_STATUS_WRITTEN;
 548		if (!(flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE) &&
 549		    !(status & EXTENT_STATUS_WRITTEN) &&
 550		    ext4_find_delalloc_range(inode, map->m_lblk,
 551					     map->m_lblk + map->m_len - 1))
 552			status |= EXTENT_STATUS_DELAYED;
 553		ret = ext4_es_insert_extent(inode, map->m_lblk,
 554					    map->m_len, map->m_pblk, status);
 555		if (ret < 0)
 556			retval = ret;
 557	}
 558	up_read((&EXT4_I(inode)->i_data_sem));
 
 559
 560found:
 561	if (retval > 0 && map->m_flags & EXT4_MAP_MAPPED) {
 562		ret = check_block_validity(inode, map);
 563		if (ret != 0)
 564			return ret;
 565	}
 566
 567	/* If it is only a block(s) look up */
 568	if ((flags & EXT4_GET_BLOCKS_CREATE) == 0)
 569		return retval;
 570
 571	/*
 572	 * Returns if the blocks have already allocated
 573	 *
 574	 * Note that if blocks have been preallocated
 575	 * ext4_ext_get_block() returns the create = 0
 576	 * with buffer head unmapped.
 577	 */
 578	if (retval > 0 && map->m_flags & EXT4_MAP_MAPPED)
 579		/*
 580		 * If we need to convert extent to unwritten
 581		 * we continue and do the actual work in
 582		 * ext4_ext_map_blocks()
 583		 */
 584		if (!(flags & EXT4_GET_BLOCKS_CONVERT_UNWRITTEN))
 585			return retval;
 586
 587	/*
 588	 * Here we clear m_flags because after allocating an new extent,
 589	 * it will be set again.
 590	 */
 591	map->m_flags &= ~EXT4_MAP_FLAGS;
 592
 593	/*
 594	 * New blocks allocate and/or writing to unwritten extent
 595	 * will possibly result in updating i_data, so we take
 596	 * the write lock of i_data_sem, and call get_block()
 597	 * with create == 1 flag.
 598	 */
 599	down_write(&EXT4_I(inode)->i_data_sem);
 600
 601	/*
 
 
 
 
 
 
 
 
 602	 * We need to check for EXT4 here because migrate
 603	 * could have changed the inode type in between
 604	 */
 605	if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) {
 606		retval = ext4_ext_map_blocks(handle, inode, map, flags);
 607	} else {
 608		retval = ext4_ind_map_blocks(handle, inode, map, flags);
 609
 610		if (retval > 0 && map->m_flags & EXT4_MAP_NEW) {
 611			/*
 612			 * We allocated new blocks which will result in
 613			 * i_data's format changing.  Force the migrate
 614			 * to fail by clearing migrate flags
 615			 */
 616			ext4_clear_inode_state(inode, EXT4_STATE_EXT_MIGRATE);
 617		}
 618
 619		/*
 620		 * Update reserved blocks/metadata blocks after successful
 621		 * block allocation which had been deferred till now. We don't
 622		 * support fallocate for non extent files. So we can update
 623		 * reserve space here.
 624		 */
 625		if ((retval > 0) &&
 626			(flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE))
 627			ext4_da_update_reserve_space(inode, retval, 1);
 628	}
 
 
 629
 630	if (retval > 0) {
 631		unsigned int status;
 632
 633		if (unlikely(retval != map->m_len)) {
 634			ext4_warning(inode->i_sb,
 635				     "ES len assertion failed for inode "
 636				     "%lu: retval %d != map->m_len %d",
 637				     inode->i_ino, retval, map->m_len);
 638			WARN_ON(1);
 639		}
 640
 641		/*
 642		 * We have to zeroout blocks before inserting them into extent
 643		 * status tree. Otherwise someone could look them up there and
 644		 * use them before they are really zeroed.
 645		 */
 646		if (flags & EXT4_GET_BLOCKS_ZERO &&
 647		    map->m_flags & EXT4_MAP_MAPPED &&
 648		    map->m_flags & EXT4_MAP_NEW) {
 649			ret = ext4_issue_zeroout(inode, map->m_lblk,
 650						 map->m_pblk, map->m_len);
 651			if (ret) {
 652				retval = ret;
 653				goto out_sem;
 654			}
 655		}
 656
 657		/*
 658		 * If the extent has been zeroed out, we don't need to update
 659		 * extent status tree.
 660		 */
 661		if ((flags & EXT4_GET_BLOCKS_PRE_IO) &&
 662		    ext4_es_lookup_extent(inode, map->m_lblk, &es)) {
 663			if (ext4_es_is_written(&es))
 664				goto out_sem;
 665		}
 666		status = map->m_flags & EXT4_MAP_UNWRITTEN ?
 667				EXTENT_STATUS_UNWRITTEN : EXTENT_STATUS_WRITTEN;
 668		if (!(flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE) &&
 669		    !(status & EXTENT_STATUS_WRITTEN) &&
 670		    ext4_find_delalloc_range(inode, map->m_lblk,
 671					     map->m_lblk + map->m_len - 1))
 672			status |= EXTENT_STATUS_DELAYED;
 673		ret = ext4_es_insert_extent(inode, map->m_lblk, map->m_len,
 674					    map->m_pblk, status);
 675		if (ret < 0) {
 676			retval = ret;
 677			goto out_sem;
 678		}
 679	}
 680
 681out_sem:
 682	up_write((&EXT4_I(inode)->i_data_sem));
 683	if (retval > 0 && map->m_flags & EXT4_MAP_MAPPED) {
 684		ret = check_block_validity(inode, map);
 685		if (ret != 0)
 686			return ret;
 687	}
 688	return retval;
 689}
 690
 691/*
 692 * Update EXT4_MAP_FLAGS in bh->b_state. For buffer heads attached to pages
 693 * we have to be careful as someone else may be manipulating b_state as well.
 694 */
 695static void ext4_update_bh_state(struct buffer_head *bh, unsigned long flags)
 696{
 697	unsigned long old_state;
 698	unsigned long new_state;
 699
 700	flags &= EXT4_MAP_FLAGS;
 701
 702	/* Dummy buffer_head? Set non-atomically. */
 703	if (!bh->b_page) {
 704		bh->b_state = (bh->b_state & ~EXT4_MAP_FLAGS) | flags;
 705		return;
 706	}
 707	/*
 708	 * Someone else may be modifying b_state. Be careful! This is ugly but
 709	 * once we get rid of using bh as a container for mapping information
 710	 * to pass to / from get_block functions, this can go away.
 711	 */
 712	do {
 713		old_state = READ_ONCE(bh->b_state);
 714		new_state = (old_state & ~EXT4_MAP_FLAGS) | flags;
 715	} while (unlikely(
 716		 cmpxchg(&bh->b_state, old_state, new_state) != old_state));
 717}
 718
 719static int _ext4_get_block(struct inode *inode, sector_t iblock,
 720			   struct buffer_head *bh, int flags)
 721{
 
 722	struct ext4_map_blocks map;
 723	int ret = 0;
 
 724
 725	if (ext4_has_inline_data(inode))
 726		return -ERANGE;
 727
 728	map.m_lblk = iblock;
 729	map.m_len = bh->b_size >> inode->i_blkbits;
 730
 731	ret = ext4_map_blocks(ext4_journal_current_handle(), inode, &map,
 732			      flags);
 
 
 
 
 
 
 
 
 
 
 
 
 
 733	if (ret > 0) {
 
 
 734		map_bh(bh, inode->i_sb, map.m_pblk);
 735		ext4_update_bh_state(bh, map.m_flags);
 
 
 736		bh->b_size = inode->i_sb->s_blocksize * map.m_len;
 737		ret = 0;
 738	}
 
 
 739	return ret;
 740}
 741
 742int ext4_get_block(struct inode *inode, sector_t iblock,
 743		   struct buffer_head *bh, int create)
 744{
 745	return _ext4_get_block(inode, iblock, bh,
 746			       create ? EXT4_GET_BLOCKS_CREATE : 0);
 747}
 748
 749/*
 750 * Get block function used when preparing for buffered write if we require
 751 * creating an unwritten extent if blocks haven't been allocated.  The extent
 752 * will be converted to written after the IO is complete.
 753 */
 754int ext4_get_block_unwritten(struct inode *inode, sector_t iblock,
 755			     struct buffer_head *bh_result, int create)
 756{
 757	ext4_debug("ext4_get_block_unwritten: inode %lu, create flag %d\n",
 758		   inode->i_ino, create);
 759	return _ext4_get_block(inode, iblock, bh_result,
 760			       EXT4_GET_BLOCKS_IO_CREATE_EXT);
 761}
 762
 763/* Maximum number of blocks we map for direct IO at once. */
 764#define DIO_MAX_BLOCKS 4096
 765
 766/*
 767 * Get blocks function for the cases that need to start a transaction -
 768 * generally difference cases of direct IO and DAX IO. It also handles retries
 769 * in case of ENOSPC.
 770 */
 771static int ext4_get_block_trans(struct inode *inode, sector_t iblock,
 772				struct buffer_head *bh_result, int flags)
 773{
 774	int dio_credits;
 775	handle_t *handle;
 776	int retries = 0;
 777	int ret;
 778
 779	/* Trim mapping request to maximum we can map at once for DIO */
 780	if (bh_result->b_size >> inode->i_blkbits > DIO_MAX_BLOCKS)
 781		bh_result->b_size = DIO_MAX_BLOCKS << inode->i_blkbits;
 782	dio_credits = ext4_chunk_trans_blocks(inode,
 783				      bh_result->b_size >> inode->i_blkbits);
 784retry:
 785	handle = ext4_journal_start(inode, EXT4_HT_MAP_BLOCKS, dio_credits);
 786	if (IS_ERR(handle))
 787		return PTR_ERR(handle);
 788
 789	ret = _ext4_get_block(inode, iblock, bh_result, flags);
 790	ext4_journal_stop(handle);
 791
 792	if (ret == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
 793		goto retry;
 794	return ret;
 795}
 796
 797/* Get block function for DIO reads and writes to inodes without extents */
 798int ext4_dio_get_block(struct inode *inode, sector_t iblock,
 799		       struct buffer_head *bh, int create)
 800{
 801	/* We don't expect handle for direct IO */
 802	WARN_ON_ONCE(ext4_journal_current_handle());
 803
 804	if (!create)
 805		return _ext4_get_block(inode, iblock, bh, 0);
 806	return ext4_get_block_trans(inode, iblock, bh, EXT4_GET_BLOCKS_CREATE);
 807}
 808
 809/*
 810 * Get block function for AIO DIO writes when we create unwritten extent if
 811 * blocks are not allocated yet. The extent will be converted to written
 812 * after IO is complete.
 813 */
 814static int ext4_dio_get_block_unwritten_async(struct inode *inode,
 815		sector_t iblock, struct buffer_head *bh_result,	int create)
 816{
 817	int ret;
 818
 819	/* We don't expect handle for direct IO */
 820	WARN_ON_ONCE(ext4_journal_current_handle());
 821
 822	ret = ext4_get_block_trans(inode, iblock, bh_result,
 823				   EXT4_GET_BLOCKS_IO_CREATE_EXT);
 824
 825	/*
 826	 * When doing DIO using unwritten extents, we need io_end to convert
 827	 * unwritten extents to written on IO completion. We allocate io_end
 828	 * once we spot unwritten extent and store it in b_private. Generic
 829	 * DIO code keeps b_private set and furthermore passes the value to
 830	 * our completion callback in 'private' argument.
 831	 */
 832	if (!ret && buffer_unwritten(bh_result)) {
 833		if (!bh_result->b_private) {
 834			ext4_io_end_t *io_end;
 835
 836			io_end = ext4_init_io_end(inode, GFP_KERNEL);
 837			if (!io_end)
 838				return -ENOMEM;
 839			bh_result->b_private = io_end;
 840			ext4_set_io_unwritten_flag(inode, io_end);
 841		}
 842		set_buffer_defer_completion(bh_result);
 843	}
 844
 845	return ret;
 846}
 847
 848/*
 849 * Get block function for non-AIO DIO writes when we create unwritten extent if
 850 * blocks are not allocated yet. The extent will be converted to written
 851 * after IO is complete from ext4_ext_direct_IO() function.
 852 */
 853static int ext4_dio_get_block_unwritten_sync(struct inode *inode,
 854		sector_t iblock, struct buffer_head *bh_result,	int create)
 855{
 856	int ret;
 857
 858	/* We don't expect handle for direct IO */
 859	WARN_ON_ONCE(ext4_journal_current_handle());
 860
 861	ret = ext4_get_block_trans(inode, iblock, bh_result,
 862				   EXT4_GET_BLOCKS_IO_CREATE_EXT);
 863
 864	/*
 865	 * Mark inode as having pending DIO writes to unwritten extents.
 866	 * ext4_ext_direct_IO() checks this flag and converts extents to
 867	 * written.
 868	 */
 869	if (!ret && buffer_unwritten(bh_result))
 870		ext4_set_inode_state(inode, EXT4_STATE_DIO_UNWRITTEN);
 871
 872	return ret;
 873}
 874
 875static int ext4_dio_get_block_overwrite(struct inode *inode, sector_t iblock,
 876		   struct buffer_head *bh_result, int create)
 877{
 878	int ret;
 879
 880	ext4_debug("ext4_dio_get_block_overwrite: inode %lu, create flag %d\n",
 881		   inode->i_ino, create);
 882	/* We don't expect handle for direct IO */
 883	WARN_ON_ONCE(ext4_journal_current_handle());
 884
 885	ret = _ext4_get_block(inode, iblock, bh_result, 0);
 886	/*
 887	 * Blocks should have been preallocated! ext4_file_write_iter() checks
 888	 * that.
 889	 */
 890	WARN_ON_ONCE(!buffer_mapped(bh_result) || buffer_unwritten(bh_result));
 891
 892	return ret;
 893}
 894
 895
 896/*
 897 * `handle' can be NULL if create is zero
 898 */
 899struct buffer_head *ext4_getblk(handle_t *handle, struct inode *inode,
 900				ext4_lblk_t block, int map_flags)
 901{
 902	struct ext4_map_blocks map;
 903	struct buffer_head *bh;
 904	int create = map_flags & EXT4_GET_BLOCKS_CREATE;
 905	int err;
 906
 907	J_ASSERT(handle != NULL || create == 0);
 908
 909	map.m_lblk = block;
 910	map.m_len = 1;
 911	err = ext4_map_blocks(handle, inode, &map, map_flags);
 
 912
 913	if (err == 0)
 914		return create ? ERR_PTR(-ENOSPC) : NULL;
 
 
 
 915	if (err < 0)
 916		return ERR_PTR(err);
 
 
 917
 918	bh = sb_getblk(inode->i_sb, map.m_pblk);
 919	if (unlikely(!bh))
 920		return ERR_PTR(-ENOMEM);
 
 
 921	if (map.m_flags & EXT4_MAP_NEW) {
 922		J_ASSERT(create != 0);
 923		J_ASSERT(handle != NULL);
 924
 925		/*
 926		 * Now that we do not always journal data, we should
 927		 * keep in mind whether this should always journal the
 928		 * new buffer as metadata.  For now, regular file
 929		 * writes use ext4_get_block instead, so it's not a
 930		 * problem.
 931		 */
 932		lock_buffer(bh);
 933		BUFFER_TRACE(bh, "call get_create_access");
 934		err = ext4_journal_get_create_access(handle, bh);
 935		if (unlikely(err)) {
 936			unlock_buffer(bh);
 937			goto errout;
 938		}
 939		if (!buffer_uptodate(bh)) {
 940			memset(bh->b_data, 0, inode->i_sb->s_blocksize);
 941			set_buffer_uptodate(bh);
 942		}
 943		unlock_buffer(bh);
 944		BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
 945		err = ext4_handle_dirty_metadata(handle, inode, bh);
 946		if (unlikely(err))
 947			goto errout;
 948	} else
 949		BUFFER_TRACE(bh, "not a new buffer");
 
 
 
 
 
 
 950	return bh;
 951errout:
 952	brelse(bh);
 953	return ERR_PTR(err);
 954}
 955
 956struct buffer_head *ext4_bread(handle_t *handle, struct inode *inode,
 957			       ext4_lblk_t block, int map_flags)
 958{
 959	struct buffer_head *bh;
 960
 961	bh = ext4_getblk(handle, inode, block, map_flags);
 962	if (IS_ERR(bh))
 963		return bh;
 964	if (!bh || buffer_uptodate(bh))
 965		return bh;
 966	ll_rw_block(READ | REQ_META | REQ_PRIO, 1, &bh);
 967	wait_on_buffer(bh);
 968	if (buffer_uptodate(bh))
 969		return bh;
 970	put_bh(bh);
 971	return ERR_PTR(-EIO);
 
 972}
 973
 974int ext4_walk_page_buffers(handle_t *handle,
 975			   struct buffer_head *head,
 976			   unsigned from,
 977			   unsigned to,
 978			   int *partial,
 979			   int (*fn)(handle_t *handle,
 980				     struct buffer_head *bh))
 981{
 982	struct buffer_head *bh;
 983	unsigned block_start, block_end;
 984	unsigned blocksize = head->b_size;
 985	int err, ret = 0;
 986	struct buffer_head *next;
 987
 988	for (bh = head, block_start = 0;
 989	     ret == 0 && (bh != head || !block_start);
 990	     block_start = block_end, bh = next) {
 991		next = bh->b_this_page;
 992		block_end = block_start + blocksize;
 993		if (block_end <= from || block_start >= to) {
 994			if (partial && !buffer_uptodate(bh))
 995				*partial = 1;
 996			continue;
 997		}
 998		err = (*fn)(handle, bh);
 999		if (!ret)
1000			ret = err;
1001	}
1002	return ret;
1003}
1004
1005/*
1006 * To preserve ordering, it is essential that the hole instantiation and
1007 * the data write be encapsulated in a single transaction.  We cannot
1008 * close off a transaction and start a new one between the ext4_get_block()
1009 * and the commit_write().  So doing the jbd2_journal_start at the start of
1010 * prepare_write() is the right place.
1011 *
1012 * Also, this function can nest inside ext4_writepage().  In that case, we
1013 * *know* that ext4_writepage() has generated enough buffer credits to do the
1014 * whole page.  So we won't block on the journal in that case, which is good,
1015 * because the caller may be PF_MEMALLOC.
1016 *
1017 * By accident, ext4 can be reentered when a transaction is open via
1018 * quota file writes.  If we were to commit the transaction while thus
1019 * reentered, there can be a deadlock - we would be holding a quota
1020 * lock, and the commit would never complete if another thread had a
1021 * transaction open and was blocking on the quota lock - a ranking
1022 * violation.
1023 *
1024 * So what we do is to rely on the fact that jbd2_journal_stop/journal_start
1025 * will _not_ run commit under these circumstances because handle->h_ref
1026 * is elevated.  We'll still have enough credits for the tiny quotafile
1027 * write.
1028 */
1029int do_journal_get_write_access(handle_t *handle,
1030				struct buffer_head *bh)
1031{
1032	int dirty = buffer_dirty(bh);
1033	int ret;
1034
1035	if (!buffer_mapped(bh) || buffer_freed(bh))
1036		return 0;
1037	/*
1038	 * __block_write_begin() could have dirtied some buffers. Clean
1039	 * the dirty bit as jbd2_journal_get_write_access() could complain
1040	 * otherwise about fs integrity issues. Setting of the dirty bit
1041	 * by __block_write_begin() isn't a real problem here as we clear
1042	 * the bit before releasing a page lock and thus writeback cannot
1043	 * ever write the buffer.
1044	 */
1045	if (dirty)
1046		clear_buffer_dirty(bh);
1047	BUFFER_TRACE(bh, "get write access");
1048	ret = ext4_journal_get_write_access(handle, bh);
1049	if (!ret && dirty)
1050		ret = ext4_handle_dirty_metadata(handle, NULL, bh);
1051	return ret;
1052}
1053
1054#ifdef CONFIG_EXT4_FS_ENCRYPTION
1055static int ext4_block_write_begin(struct page *page, loff_t pos, unsigned len,
1056				  get_block_t *get_block)
1057{
1058	unsigned from = pos & (PAGE_SIZE - 1);
1059	unsigned to = from + len;
1060	struct inode *inode = page->mapping->host;
1061	unsigned block_start, block_end;
1062	sector_t block;
1063	int err = 0;
1064	unsigned blocksize = inode->i_sb->s_blocksize;
1065	unsigned bbits;
1066	struct buffer_head *bh, *head, *wait[2], **wait_bh = wait;
1067	bool decrypt = false;
1068
1069	BUG_ON(!PageLocked(page));
1070	BUG_ON(from > PAGE_SIZE);
1071	BUG_ON(to > PAGE_SIZE);
1072	BUG_ON(from > to);
1073
1074	if (!page_has_buffers(page))
1075		create_empty_buffers(page, blocksize, 0);
1076	head = page_buffers(page);
1077	bbits = ilog2(blocksize);
1078	block = (sector_t)page->index << (PAGE_SHIFT - bbits);
1079
1080	for (bh = head, block_start = 0; bh != head || !block_start;
1081	    block++, block_start = block_end, bh = bh->b_this_page) {
1082		block_end = block_start + blocksize;
1083		if (block_end <= from || block_start >= to) {
1084			if (PageUptodate(page)) {
1085				if (!buffer_uptodate(bh))
1086					set_buffer_uptodate(bh);
1087			}
1088			continue;
1089		}
1090		if (buffer_new(bh))
1091			clear_buffer_new(bh);
1092		if (!buffer_mapped(bh)) {
1093			WARN_ON(bh->b_size != blocksize);
1094			err = get_block(inode, block, bh, 1);
1095			if (err)
1096				break;
1097			if (buffer_new(bh)) {
1098				unmap_underlying_metadata(bh->b_bdev,
1099							  bh->b_blocknr);
1100				if (PageUptodate(page)) {
1101					clear_buffer_new(bh);
1102					set_buffer_uptodate(bh);
1103					mark_buffer_dirty(bh);
1104					continue;
1105				}
1106				if (block_end > to || block_start < from)
1107					zero_user_segments(page, to, block_end,
1108							   block_start, from);
1109				continue;
1110			}
1111		}
1112		if (PageUptodate(page)) {
1113			if (!buffer_uptodate(bh))
1114				set_buffer_uptodate(bh);
1115			continue;
1116		}
1117		if (!buffer_uptodate(bh) && !buffer_delay(bh) &&
1118		    !buffer_unwritten(bh) &&
1119		    (block_start < from || block_end > to)) {
1120			ll_rw_block(READ, 1, &bh);
1121			*wait_bh++ = bh;
1122			decrypt = ext4_encrypted_inode(inode) &&
1123				S_ISREG(inode->i_mode);
1124		}
1125	}
1126	/*
1127	 * If we issued read requests, let them complete.
1128	 */
1129	while (wait_bh > wait) {
1130		wait_on_buffer(*--wait_bh);
1131		if (!buffer_uptodate(*wait_bh))
1132			err = -EIO;
1133	}
1134	if (unlikely(err))
1135		page_zero_new_buffers(page, from, to);
1136	else if (decrypt)
1137		err = ext4_decrypt(page);
1138	return err;
1139}
1140#endif
1141
1142static int ext4_write_begin(struct file *file, struct address_space *mapping,
1143			    loff_t pos, unsigned len, unsigned flags,
1144			    struct page **pagep, void **fsdata)
1145{
1146	struct inode *inode = mapping->host;
1147	int ret, needed_blocks;
1148	handle_t *handle;
1149	int retries = 0;
1150	struct page *page;
1151	pgoff_t index;
1152	unsigned from, to;
1153
1154	trace_ext4_write_begin(inode, pos, len, flags);
1155	/*
1156	 * Reserve one block more for addition to orphan list in case
1157	 * we allocate blocks but write fails for some reason
1158	 */
1159	needed_blocks = ext4_writepage_trans_blocks(inode) + 1;
1160	index = pos >> PAGE_SHIFT;
1161	from = pos & (PAGE_SIZE - 1);
1162	to = from + len;
1163
1164	if (ext4_test_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA)) {
1165		ret = ext4_try_to_write_inline_data(mapping, inode, pos, len,
1166						    flags, pagep);
1167		if (ret < 0)
1168			return ret;
1169		if (ret == 1)
1170			return 0;
1171	}
1172
1173	/*
1174	 * grab_cache_page_write_begin() can take a long time if the
1175	 * system is thrashing due to memory pressure, or if the page
1176	 * is being written back.  So grab it first before we start
1177	 * the transaction handle.  This also allows us to allocate
1178	 * the page (if needed) without using GFP_NOFS.
1179	 */
1180retry_grab:
1181	page = grab_cache_page_write_begin(mapping, index, flags);
1182	if (!page)
1183		return -ENOMEM;
1184	unlock_page(page);
1185
1186retry_journal:
1187	handle = ext4_journal_start(inode, EXT4_HT_WRITE_PAGE, needed_blocks);
1188	if (IS_ERR(handle)) {
1189		put_page(page);
1190		return PTR_ERR(handle);
1191	}
1192
1193	lock_page(page);
1194	if (page->mapping != mapping) {
1195		/* The page got truncated from under us */
1196		unlock_page(page);
1197		put_page(page);
1198		ext4_journal_stop(handle);
1199		goto retry_grab;
1200	}
1201	/* In case writeback began while the page was unlocked */
1202	wait_for_stable_page(page);
1203
1204#ifdef CONFIG_EXT4_FS_ENCRYPTION
1205	if (ext4_should_dioread_nolock(inode))
1206		ret = ext4_block_write_begin(page, pos, len,
1207					     ext4_get_block_unwritten);
1208	else
1209		ret = ext4_block_write_begin(page, pos, len,
1210					     ext4_get_block);
1211#else
1212	if (ext4_should_dioread_nolock(inode))
1213		ret = __block_write_begin(page, pos, len,
1214					  ext4_get_block_unwritten);
1215	else
1216		ret = __block_write_begin(page, pos, len, ext4_get_block);
1217#endif
1218	if (!ret && ext4_should_journal_data(inode)) {
1219		ret = ext4_walk_page_buffers(handle, page_buffers(page),
1220					     from, to, NULL,
1221					     do_journal_get_write_access);
1222	}
1223
1224	if (ret) {
1225		unlock_page(page);
1226		/*
1227		 * __block_write_begin may have instantiated a few blocks
1228		 * outside i_size.  Trim these off again. Don't need
1229		 * i_size_read because we hold i_mutex.
1230		 *
1231		 * Add inode to orphan list in case we crash before
1232		 * truncate finishes
1233		 */
1234		if (pos + len > inode->i_size && ext4_can_truncate(inode))
1235			ext4_orphan_add(handle, inode);
1236
1237		ext4_journal_stop(handle);
1238		if (pos + len > inode->i_size) {
1239			ext4_truncate_failed_write(inode);
1240			/*
1241			 * If truncate failed early the inode might
1242			 * still be on the orphan list; we need to
1243			 * make sure the inode is removed from the
1244			 * orphan list in that case.
1245			 */
1246			if (inode->i_nlink)
1247				ext4_orphan_del(NULL, inode);
1248		}
1249
1250		if (ret == -ENOSPC &&
1251		    ext4_should_retry_alloc(inode->i_sb, &retries))
1252			goto retry_journal;
1253		put_page(page);
1254		return ret;
1255	}
1256	*pagep = page;
1257	return ret;
1258}
1259
1260/* For write_end() in data=journal mode */
1261static int write_end_fn(handle_t *handle, struct buffer_head *bh)
1262{
1263	int ret;
1264	if (!buffer_mapped(bh) || buffer_freed(bh))
1265		return 0;
1266	set_buffer_uptodate(bh);
1267	ret = ext4_handle_dirty_metadata(handle, NULL, bh);
1268	clear_buffer_meta(bh);
1269	clear_buffer_prio(bh);
1270	return ret;
1271}
1272
1273/*
1274 * We need to pick up the new inode size which generic_commit_write gave us
1275 * `file' can be NULL - eg, when called from page_symlink().
1276 *
1277 * ext4 never places buffers on inode->i_mapping->private_list.  metadata
1278 * buffers are managed internally.
1279 */
1280static int ext4_write_end(struct file *file,
1281			  struct address_space *mapping,
1282			  loff_t pos, unsigned len, unsigned copied,
1283			  struct page *page, void *fsdata)
1284{
1285	handle_t *handle = ext4_journal_current_handle();
1286	struct inode *inode = mapping->host;
1287	loff_t old_size = inode->i_size;
1288	int ret = 0, ret2;
1289	int i_size_changed = 0;
1290
1291	trace_ext4_write_end(inode, pos, len, copied);
1292	if (ext4_test_inode_state(inode, EXT4_STATE_ORDERED_MODE)) {
1293		ret = ext4_jbd2_file_inode(handle, inode);
1294		if (ret) {
1295			unlock_page(page);
1296			put_page(page);
1297			goto errout;
1298		}
1299	}
1300
1301	if (ext4_has_inline_data(inode)) {
1302		ret = ext4_write_inline_data_end(inode, pos, len,
1303						 copied, page);
1304		if (ret < 0)
1305			goto errout;
1306		copied = ret;
1307	} else
1308		copied = block_write_end(file, mapping, pos,
1309					 len, copied, page, fsdata);
 
1310	/*
1311	 * it's important to update i_size while still holding page lock:
 
 
 
1312	 * page writeout could otherwise come in and zero beyond i_size.
1313	 */
1314	i_size_changed = ext4_update_inode_size(inode, pos + copied);
 
 
 
 
 
 
 
 
 
 
 
 
1315	unlock_page(page);
1316	put_page(page);
1317
1318	if (old_size < pos)
1319		pagecache_isize_extended(inode, old_size, pos);
1320	/*
1321	 * Don't mark the inode dirty under page lock. First, it unnecessarily
1322	 * makes the holding time of page lock longer. Second, it forces lock
1323	 * ordering of page lock and transaction start for journaling
1324	 * filesystems.
1325	 */
1326	if (i_size_changed)
1327		ext4_mark_inode_dirty(handle, inode);
1328
1329	if (pos + len > inode->i_size && ext4_can_truncate(inode))
1330		/* if we have allocated more blocks and copied
1331		 * less. We will have blocks allocated outside
1332		 * inode->i_size. So truncate them
1333		 */
1334		ext4_orphan_add(handle, inode);
1335errout:
1336	ret2 = ext4_journal_stop(handle);
1337	if (!ret)
1338		ret = ret2;
1339
1340	if (pos + len > inode->i_size) {
1341		ext4_truncate_failed_write(inode);
1342		/*
1343		 * If truncate failed early the inode might still be
1344		 * on the orphan list; we need to make sure the inode
1345		 * is removed from the orphan list in that case.
1346		 */
1347		if (inode->i_nlink)
1348			ext4_orphan_del(NULL, inode);
1349	}
1350
1351	return ret ? ret : copied;
1352}
1353
1354/*
1355 * This is a private version of page_zero_new_buffers() which doesn't
1356 * set the buffer to be dirty, since in data=journalled mode we need
1357 * to call ext4_handle_dirty_metadata() instead.
1358 */
1359static void zero_new_buffers(struct page *page, unsigned from, unsigned to)
1360{
1361	unsigned int block_start = 0, block_end;
1362	struct buffer_head *head, *bh;
1363
1364	bh = head = page_buffers(page);
1365	do {
1366		block_end = block_start + bh->b_size;
1367		if (buffer_new(bh)) {
1368			if (block_end > from && block_start < to) {
1369				if (!PageUptodate(page)) {
1370					unsigned start, size;
1371
1372					start = max(from, block_start);
1373					size = min(to, block_end) - start;
1374
1375					zero_user(page, start, size);
1376					set_buffer_uptodate(bh);
1377				}
1378				clear_buffer_new(bh);
1379			}
1380		}
1381		block_start = block_end;
1382		bh = bh->b_this_page;
1383	} while (bh != head);
1384}
1385
1386static int ext4_journalled_write_end(struct file *file,
1387				     struct address_space *mapping,
1388				     loff_t pos, unsigned len, unsigned copied,
1389				     struct page *page, void *fsdata)
1390{
1391	handle_t *handle = ext4_journal_current_handle();
1392	struct inode *inode = mapping->host;
1393	loff_t old_size = inode->i_size;
1394	int ret = 0, ret2;
1395	int partial = 0;
1396	unsigned from, to;
1397	int size_changed = 0;
1398
1399	trace_ext4_journalled_write_end(inode, pos, len, copied);
1400	from = pos & (PAGE_SIZE - 1);
1401	to = from + len;
1402
1403	BUG_ON(!ext4_handle_valid(handle));
1404
1405	if (ext4_has_inline_data(inode))
1406		copied = ext4_write_inline_data_end(inode, pos, len,
1407						    copied, page);
1408	else {
1409		if (copied < len) {
1410			if (!PageUptodate(page))
1411				copied = 0;
1412			zero_new_buffers(page, from+copied, to);
1413		}
1414
1415		ret = ext4_walk_page_buffers(handle, page_buffers(page), from,
1416					     to, &partial, write_end_fn);
1417		if (!partial)
1418			SetPageUptodate(page);
1419	}
1420	size_changed = ext4_update_inode_size(inode, pos + copied);
 
 
1421	ext4_set_inode_state(inode, EXT4_STATE_JDATA);
1422	EXT4_I(inode)->i_datasync_tid = handle->h_transaction->t_tid;
1423	unlock_page(page);
1424	put_page(page);
1425
1426	if (old_size < pos)
1427		pagecache_isize_extended(inode, old_size, pos);
1428
1429	if (size_changed) {
1430		ret2 = ext4_mark_inode_dirty(handle, inode);
1431		if (!ret)
1432			ret = ret2;
1433	}
1434
 
 
1435	if (pos + len > inode->i_size && ext4_can_truncate(inode))
1436		/* if we have allocated more blocks and copied
1437		 * less. We will have blocks allocated outside
1438		 * inode->i_size. So truncate them
1439		 */
1440		ext4_orphan_add(handle, inode);
1441
1442	ret2 = ext4_journal_stop(handle);
1443	if (!ret)
1444		ret = ret2;
1445	if (pos + len > inode->i_size) {
1446		ext4_truncate_failed_write(inode);
1447		/*
1448		 * If truncate failed early the inode might still be
1449		 * on the orphan list; we need to make sure the inode
1450		 * is removed from the orphan list in that case.
1451		 */
1452		if (inode->i_nlink)
1453			ext4_orphan_del(NULL, inode);
1454	}
1455
1456	return ret ? ret : copied;
1457}
1458
1459/*
1460 * Reserve space for a single cluster
1461 */
1462static int ext4_da_reserve_space(struct inode *inode)
1463{
1464	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
1465	struct ext4_inode_info *ei = EXT4_I(inode);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1466	int ret;
 
 
1467
1468	/*
1469	 * We will charge metadata quota at writeout time; this saves
1470	 * us from metadata over-estimation, though we may go over by
1471	 * a small amount in the end.  Here we just reserve for data.
1472	 */
1473	ret = dquot_reserve_block(inode, EXT4_C2B(sbi, 1));
1474	if (ret)
1475		return ret;
1476
 
 
 
 
 
1477	spin_lock(&ei->i_block_reservation_lock);
1478	if (ext4_claim_free_clusters(sbi, 1, 0)) {
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1479		spin_unlock(&ei->i_block_reservation_lock);
1480		dquot_release_reservation_block(inode, EXT4_C2B(sbi, 1));
1481		return -ENOSPC;
1482	}
1483	ei->i_reserved_data_blocks++;
1484	trace_ext4_da_reserve_space(inode);
1485	spin_unlock(&ei->i_block_reservation_lock);
1486
1487	return 0;       /* success */
1488}
1489
1490static void ext4_da_release_space(struct inode *inode, int to_free)
1491{
1492	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
1493	struct ext4_inode_info *ei = EXT4_I(inode);
1494
1495	if (!to_free)
1496		return;		/* Nothing to release, exit */
1497
1498	spin_lock(&EXT4_I(inode)->i_block_reservation_lock);
1499
1500	trace_ext4_da_release_space(inode, to_free);
1501	if (unlikely(to_free > ei->i_reserved_data_blocks)) {
1502		/*
1503		 * if there aren't enough reserved blocks, then the
1504		 * counter is messed up somewhere.  Since this
1505		 * function is called from invalidate page, it's
1506		 * harmless to return without any action.
1507		 */
1508		ext4_warning(inode->i_sb, "ext4_da_release_space: "
1509			 "ino %lu, to_free %d with only %d reserved "
1510			 "data blocks", inode->i_ino, to_free,
1511			 ei->i_reserved_data_blocks);
1512		WARN_ON(1);
1513		to_free = ei->i_reserved_data_blocks;
1514	}
1515	ei->i_reserved_data_blocks -= to_free;
1516
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1517	/* update fs dirty data blocks counter */
1518	percpu_counter_sub(&sbi->s_dirtyclusters_counter, to_free);
1519
1520	spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
1521
1522	dquot_release_reservation_block(inode, EXT4_C2B(sbi, to_free));
1523}
1524
1525static void ext4_da_page_release_reservation(struct page *page,
1526					     unsigned int offset,
1527					     unsigned int length)
1528{
1529	int to_release = 0, contiguous_blks = 0;
1530	struct buffer_head *head, *bh;
1531	unsigned int curr_off = 0;
1532	struct inode *inode = page->mapping->host;
1533	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
1534	unsigned int stop = offset + length;
1535	int num_clusters;
1536	ext4_fsblk_t lblk;
1537
1538	BUG_ON(stop > PAGE_SIZE || stop < length);
1539
1540	head = page_buffers(page);
1541	bh = head;
1542	do {
1543		unsigned int next_off = curr_off + bh->b_size;
1544
1545		if (next_off > stop)
1546			break;
1547
1548		if ((offset <= curr_off) && (buffer_delay(bh))) {
1549			to_release++;
1550			contiguous_blks++;
1551			clear_buffer_delay(bh);
1552		} else if (contiguous_blks) {
1553			lblk = page->index <<
1554			       (PAGE_SHIFT - inode->i_blkbits);
1555			lblk += (curr_off >> inode->i_blkbits) -
1556				contiguous_blks;
1557			ext4_es_remove_extent(inode, lblk, contiguous_blks);
1558			contiguous_blks = 0;
1559		}
1560		curr_off = next_off;
1561	} while ((bh = bh->b_this_page) != head);
1562
1563	if (contiguous_blks) {
1564		lblk = page->index << (PAGE_SHIFT - inode->i_blkbits);
1565		lblk += (curr_off >> inode->i_blkbits) - contiguous_blks;
1566		ext4_es_remove_extent(inode, lblk, contiguous_blks);
1567	}
1568
1569	/* If we have released all the blocks belonging to a cluster, then we
1570	 * need to release the reserved space for that cluster. */
1571	num_clusters = EXT4_NUM_B2C(sbi, to_release);
1572	while (num_clusters > 0) {
1573		lblk = (page->index << (PAGE_SHIFT - inode->i_blkbits)) +
1574			((num_clusters - 1) << sbi->s_cluster_bits);
1575		if (sbi->s_cluster_ratio == 1 ||
1576		    !ext4_find_delalloc_cluster(inode, lblk))
1577			ext4_da_release_space(inode, 1);
1578
1579		num_clusters--;
1580	}
1581}
1582
1583/*
1584 * Delayed allocation stuff
1585 */
1586
1587struct mpage_da_data {
1588	struct inode *inode;
1589	struct writeback_control *wbc;
1590
1591	pgoff_t first_page;	/* The first page to write */
1592	pgoff_t next_page;	/* Current page to examine */
1593	pgoff_t last_page;	/* Last page to examine */
1594	/*
1595	 * Extent to map - this can be after first_page because that can be
1596	 * fully mapped. We somewhat abuse m_flags to store whether the extent
1597	 * is delalloc or unwritten.
1598	 */
1599	struct ext4_map_blocks map;
1600	struct ext4_io_submit io_submit;	/* IO submission data */
1601};
1602
1603static void mpage_release_unused_pages(struct mpage_da_data *mpd,
1604				       bool invalidate)
1605{
1606	int nr_pages, i;
1607	pgoff_t index, end;
1608	struct pagevec pvec;
1609	struct inode *inode = mpd->inode;
1610	struct address_space *mapping = inode->i_mapping;
1611
1612	/* This is necessary when next_page == 0. */
1613	if (mpd->first_page >= mpd->next_page)
1614		return;
1615
1616	index = mpd->first_page;
1617	end   = mpd->next_page - 1;
1618	if (invalidate) {
1619		ext4_lblk_t start, last;
1620		start = index << (PAGE_SHIFT - inode->i_blkbits);
1621		last = end << (PAGE_SHIFT - inode->i_blkbits);
1622		ext4_es_remove_extent(inode, start, last - start + 1);
1623	}
1624
1625	pagevec_init(&pvec, 0);
1626	while (index <= end) {
1627		nr_pages = pagevec_lookup(&pvec, mapping, index, PAGEVEC_SIZE);
1628		if (nr_pages == 0)
1629			break;
1630		for (i = 0; i < nr_pages; i++) {
1631			struct page *page = pvec.pages[i];
1632			if (page->index > end)
1633				break;
1634			BUG_ON(!PageLocked(page));
1635			BUG_ON(PageWriteback(page));
1636			if (invalidate) {
1637				block_invalidatepage(page, 0, PAGE_SIZE);
1638				ClearPageUptodate(page);
1639			}
1640			unlock_page(page);
1641		}
1642		index = pvec.pages[nr_pages - 1]->index + 1;
1643		pagevec_release(&pvec);
1644	}
1645}
1646
1647static void ext4_print_free_blocks(struct inode *inode)
1648{
1649	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
1650	struct super_block *sb = inode->i_sb;
1651	struct ext4_inode_info *ei = EXT4_I(inode);
1652
1653	ext4_msg(sb, KERN_CRIT, "Total free blocks count %lld",
1654	       EXT4_C2B(EXT4_SB(inode->i_sb),
1655			ext4_count_free_clusters(sb)));
1656	ext4_msg(sb, KERN_CRIT, "Free/Dirty block details");
1657	ext4_msg(sb, KERN_CRIT, "free_blocks=%lld",
1658	       (long long) EXT4_C2B(EXT4_SB(sb),
1659		percpu_counter_sum(&sbi->s_freeclusters_counter)));
1660	ext4_msg(sb, KERN_CRIT, "dirty_blocks=%lld",
1661	       (long long) EXT4_C2B(EXT4_SB(sb),
1662		percpu_counter_sum(&sbi->s_dirtyclusters_counter)));
1663	ext4_msg(sb, KERN_CRIT, "Block reservation details");
1664	ext4_msg(sb, KERN_CRIT, "i_reserved_data_blocks=%u",
1665		 ei->i_reserved_data_blocks);
 
 
 
 
1666	return;
1667}
1668
1669static int ext4_bh_delay_or_unwritten(handle_t *handle, struct buffer_head *bh)
1670{
1671	return (buffer_delay(bh) || buffer_unwritten(bh)) && buffer_dirty(bh);
1672}
1673
1674/*
1675 * This function is grabs code from the very beginning of
1676 * ext4_map_blocks, but assumes that the caller is from delayed write
1677 * time. This function looks up the requested blocks and sets the
1678 * buffer delay bit under the protection of i_data_sem.
1679 */
1680static int ext4_da_map_blocks(struct inode *inode, sector_t iblock,
1681			      struct ext4_map_blocks *map,
1682			      struct buffer_head *bh)
1683{
1684	struct extent_status es;
1685	int retval;
1686	sector_t invalid_block = ~((sector_t) 0xffff);
1687#ifdef ES_AGGRESSIVE_TEST
1688	struct ext4_map_blocks orig_map;
1689
1690	memcpy(&orig_map, map, sizeof(*map));
1691#endif
1692
1693	if (invalid_block < ext4_blocks_count(EXT4_SB(inode->i_sb)->s_es))
1694		invalid_block = ~0;
1695
1696	map->m_flags = 0;
1697	ext_debug("ext4_da_map_blocks(): inode %lu, max_blocks %u,"
1698		  "logical block %lu\n", inode->i_ino, map->m_len,
1699		  (unsigned long) map->m_lblk);
1700
1701	/* Lookup extent status tree firstly */
1702	if (ext4_es_lookup_extent(inode, iblock, &es)) {
 
1703		if (ext4_es_is_hole(&es)) {
1704			retval = 0;
1705			down_read(&EXT4_I(inode)->i_data_sem);
1706			goto add_delayed;
1707		}
1708
1709		/*
1710		 * Delayed extent could be allocated by fallocate.
1711		 * So we need to check it.
1712		 */
1713		if (ext4_es_is_delayed(&es) && !ext4_es_is_unwritten(&es)) {
1714			map_bh(bh, inode->i_sb, invalid_block);
1715			set_buffer_new(bh);
1716			set_buffer_delay(bh);
1717			return 0;
1718		}
1719
1720		map->m_pblk = ext4_es_pblock(&es) + iblock - es.es_lblk;
1721		retval = es.es_len - (iblock - es.es_lblk);
1722		if (retval > map->m_len)
1723			retval = map->m_len;
1724		map->m_len = retval;
1725		if (ext4_es_is_written(&es))
1726			map->m_flags |= EXT4_MAP_MAPPED;
1727		else if (ext4_es_is_unwritten(&es))
1728			map->m_flags |= EXT4_MAP_UNWRITTEN;
1729		else
1730			BUG_ON(1);
1731
1732#ifdef ES_AGGRESSIVE_TEST
1733		ext4_map_blocks_es_recheck(NULL, inode, map, &orig_map, 0);
1734#endif
1735		return retval;
1736	}
1737
1738	/*
1739	 * Try to see if we can get the block without requesting a new
1740	 * file system block.
1741	 */
1742	down_read(&EXT4_I(inode)->i_data_sem);
1743	if (ext4_has_inline_data(inode))
 
 
 
 
 
 
 
 
 
 
1744		retval = 0;
1745	else if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
1746		retval = ext4_ext_map_blocks(NULL, inode, map, 0);
 
1747	else
1748		retval = ext4_ind_map_blocks(NULL, inode, map, 0);
 
1749
1750add_delayed:
1751	if (retval == 0) {
1752		int ret;
1753		/*
1754		 * XXX: __block_prepare_write() unmaps passed block,
1755		 * is it OK?
1756		 */
1757		/*
1758		 * If the block was allocated from previously allocated cluster,
1759		 * then we don't need to reserve it again. However we still need
1760		 * to reserve metadata for every block we're going to write.
1761		 */
1762		if (EXT4_SB(inode->i_sb)->s_cluster_ratio == 1 ||
1763		    !ext4_find_delalloc_cluster(inode, map->m_lblk)) {
1764			ret = ext4_da_reserve_space(inode);
 
 
 
 
 
 
1765			if (ret) {
1766				/* not enough space to reserve */
1767				retval = ret;
1768				goto out_unlock;
1769			}
1770		}
1771
1772		ret = ext4_es_insert_extent(inode, map->m_lblk, map->m_len,
1773					    ~0, EXTENT_STATUS_DELAYED);
1774		if (ret) {
1775			retval = ret;
1776			goto out_unlock;
1777		}
1778
 
 
 
 
 
1779		map_bh(bh, inode->i_sb, invalid_block);
1780		set_buffer_new(bh);
1781		set_buffer_delay(bh);
1782	} else if (retval > 0) {
1783		int ret;
1784		unsigned int status;
1785
1786		if (unlikely(retval != map->m_len)) {
1787			ext4_warning(inode->i_sb,
1788				     "ES len assertion failed for inode "
1789				     "%lu: retval %d != map->m_len %d",
1790				     inode->i_ino, retval, map->m_len);
1791			WARN_ON(1);
1792		}
1793
1794		status = map->m_flags & EXT4_MAP_UNWRITTEN ?
1795				EXTENT_STATUS_UNWRITTEN : EXTENT_STATUS_WRITTEN;
1796		ret = ext4_es_insert_extent(inode, map->m_lblk, map->m_len,
1797					    map->m_pblk, status);
1798		if (ret != 0)
1799			retval = ret;
1800	}
1801
1802out_unlock:
1803	up_read((&EXT4_I(inode)->i_data_sem));
1804
1805	return retval;
1806}
1807
1808/*
1809 * This is a special get_block_t callback which is used by
1810 * ext4_da_write_begin().  It will either return mapped block or
1811 * reserve space for a single block.
1812 *
1813 * For delayed buffer_head we have BH_Mapped, BH_New, BH_Delay set.
1814 * We also have b_blocknr = -1 and b_bdev initialized properly
1815 *
1816 * For unwritten buffer_head we have BH_Mapped, BH_New, BH_Unwritten set.
1817 * We also have b_blocknr = physicalblock mapping unwritten extent and b_bdev
1818 * initialized properly.
1819 */
1820int ext4_da_get_block_prep(struct inode *inode, sector_t iblock,
1821			   struct buffer_head *bh, int create)
1822{
1823	struct ext4_map_blocks map;
1824	int ret = 0;
1825
1826	BUG_ON(create == 0);
1827	BUG_ON(bh->b_size != inode->i_sb->s_blocksize);
1828
1829	map.m_lblk = iblock;
1830	map.m_len = 1;
1831
1832	/*
1833	 * first, we need to know whether the block is allocated already
1834	 * preallocated blocks are unmapped but should treated
1835	 * the same as allocated blocks.
1836	 */
1837	ret = ext4_da_map_blocks(inode, iblock, &map, bh);
1838	if (ret <= 0)
1839		return ret;
1840
1841	map_bh(bh, inode->i_sb, map.m_pblk);
1842	ext4_update_bh_state(bh, map.m_flags);
1843
1844	if (buffer_unwritten(bh)) {
1845		/* A delayed write to unwritten bh should be marked
1846		 * new and mapped.  Mapped ensures that we don't do
1847		 * get_block multiple times when we write to the same
1848		 * offset and new ensures that we do proper zero out
1849		 * for partial write.
1850		 */
1851		set_buffer_new(bh);
1852		set_buffer_mapped(bh);
1853	}
1854	return 0;
1855}
1856
1857static int bget_one(handle_t *handle, struct buffer_head *bh)
1858{
1859	get_bh(bh);
1860	return 0;
1861}
1862
1863static int bput_one(handle_t *handle, struct buffer_head *bh)
1864{
1865	put_bh(bh);
1866	return 0;
1867}
1868
1869static int __ext4_journalled_writepage(struct page *page,
1870				       unsigned int len)
1871{
1872	struct address_space *mapping = page->mapping;
1873	struct inode *inode = mapping->host;
1874	struct buffer_head *page_bufs = NULL;
1875	handle_t *handle = NULL;
1876	int ret = 0, err = 0;
1877	int inline_data = ext4_has_inline_data(inode);
1878	struct buffer_head *inode_bh = NULL;
1879
1880	ClearPageChecked(page);
1881
1882	if (inline_data) {
1883		BUG_ON(page->index != 0);
1884		BUG_ON(len > ext4_get_max_inline_size(inode));
1885		inode_bh = ext4_journalled_write_inline_data(inode, len, page);
1886		if (inode_bh == NULL)
1887			goto out;
1888	} else {
1889		page_bufs = page_buffers(page);
1890		if (!page_bufs) {
1891			BUG();
1892			goto out;
1893		}
1894		ext4_walk_page_buffers(handle, page_bufs, 0, len,
1895				       NULL, bget_one);
1896	}
1897	/*
1898	 * We need to release the page lock before we start the
1899	 * journal, so grab a reference so the page won't disappear
1900	 * out from under us.
1901	 */
1902	get_page(page);
1903	unlock_page(page);
1904
1905	handle = ext4_journal_start(inode, EXT4_HT_WRITE_PAGE,
1906				    ext4_writepage_trans_blocks(inode));
1907	if (IS_ERR(handle)) {
1908		ret = PTR_ERR(handle);
1909		put_page(page);
1910		goto out_no_pagelock;
1911	}
1912	BUG_ON(!ext4_handle_valid(handle));
1913
1914	lock_page(page);
1915	put_page(page);
1916	if (page->mapping != mapping) {
1917		/* The page got truncated from under us */
1918		ext4_journal_stop(handle);
1919		ret = 0;
1920		goto out;
1921	}
1922
 
 
1923	if (inline_data) {
1924		BUFFER_TRACE(inode_bh, "get write access");
1925		ret = ext4_journal_get_write_access(handle, inode_bh);
1926
1927		err = ext4_handle_dirty_metadata(handle, inode, inode_bh);
1928
1929	} else {
1930		ret = ext4_walk_page_buffers(handle, page_bufs, 0, len, NULL,
1931					     do_journal_get_write_access);
1932
1933		err = ext4_walk_page_buffers(handle, page_bufs, 0, len, NULL,
1934					     write_end_fn);
1935	}
1936	if (ret == 0)
1937		ret = err;
1938	EXT4_I(inode)->i_datasync_tid = handle->h_transaction->t_tid;
1939	err = ext4_journal_stop(handle);
1940	if (!ret)
1941		ret = err;
1942
1943	if (!ext4_has_inline_data(inode))
1944		ext4_walk_page_buffers(NULL, page_bufs, 0, len,
1945				       NULL, bput_one);
1946	ext4_set_inode_state(inode, EXT4_STATE_JDATA);
1947out:
1948	unlock_page(page);
1949out_no_pagelock:
1950	brelse(inode_bh);
1951	return ret;
1952}
1953
1954/*
1955 * Note that we don't need to start a transaction unless we're journaling data
1956 * because we should have holes filled from ext4_page_mkwrite(). We even don't
1957 * need to file the inode to the transaction's list in ordered mode because if
1958 * we are writing back data added by write(), the inode is already there and if
1959 * we are writing back data modified via mmap(), no one guarantees in which
1960 * transaction the data will hit the disk. In case we are journaling data, we
1961 * cannot start transaction directly because transaction start ranks above page
1962 * lock so we have to do some magic.
1963 *
1964 * This function can get called via...
1965 *   - ext4_writepages after taking page lock (have journal handle)
1966 *   - journal_submit_inode_data_buffers (no journal handle)
1967 *   - shrink_page_list via the kswapd/direct reclaim (no journal handle)
1968 *   - grab_page_cache when doing write_begin (have journal handle)
1969 *
1970 * We don't do any block allocation in this function. If we have page with
1971 * multiple blocks we need to write those buffer_heads that are mapped. This
1972 * is important for mmaped based write. So if we do with blocksize 1K
1973 * truncate(f, 1024);
1974 * a = mmap(f, 0, 4096);
1975 * a[0] = 'a';
1976 * truncate(f, 4096);
1977 * we have in the page first buffer_head mapped via page_mkwrite call back
1978 * but other buffer_heads would be unmapped but dirty (dirty done via the
1979 * do_wp_page). So writepage should write the first block. If we modify
1980 * the mmap area beyond 1024 we will again get a page_fault and the
1981 * page_mkwrite callback will do the block allocation and mark the
1982 * buffer_heads mapped.
1983 *
1984 * We redirty the page if we have any buffer_heads that is either delay or
1985 * unwritten in the page.
1986 *
1987 * We can get recursively called as show below.
1988 *
1989 *	ext4_writepage() -> kmalloc() -> __alloc_pages() -> page_launder() ->
1990 *		ext4_writepage()
1991 *
1992 * But since we don't do any block allocation we should not deadlock.
1993 * Page also have the dirty flag cleared so we don't get recurive page_lock.
1994 */
1995static int ext4_writepage(struct page *page,
1996			  struct writeback_control *wbc)
1997{
1998	int ret = 0;
1999	loff_t size;
2000	unsigned int len;
2001	struct buffer_head *page_bufs = NULL;
2002	struct inode *inode = page->mapping->host;
2003	struct ext4_io_submit io_submit;
2004	bool keep_towrite = false;
2005
2006	trace_ext4_writepage(page);
2007	size = i_size_read(inode);
2008	if (page->index == size >> PAGE_SHIFT)
2009		len = size & ~PAGE_MASK;
2010	else
2011		len = PAGE_SIZE;
2012
2013	page_bufs = page_buffers(page);
2014	/*
2015	 * We cannot do block allocation or other extent handling in this
2016	 * function. If there are buffers needing that, we have to redirty
2017	 * the page. But we may reach here when we do a journal commit via
2018	 * journal_submit_inode_data_buffers() and in that case we must write
2019	 * allocated buffers to achieve data=ordered mode guarantees.
2020	 *
2021	 * Also, if there is only one buffer per page (the fs block
2022	 * size == the page size), if one buffer needs block
2023	 * allocation or needs to modify the extent tree to clear the
2024	 * unwritten flag, we know that the page can't be written at
2025	 * all, so we might as well refuse the write immediately.
2026	 * Unfortunately if the block size != page size, we can't as
2027	 * easily detect this case using ext4_walk_page_buffers(), but
2028	 * for the extremely common case, this is an optimization that
2029	 * skips a useless round trip through ext4_bio_write_page().
2030	 */
2031	if (ext4_walk_page_buffers(NULL, page_bufs, 0, len, NULL,
2032				   ext4_bh_delay_or_unwritten)) {
2033		redirty_page_for_writepage(wbc, page);
2034		if ((current->flags & PF_MEMALLOC) ||
2035		    (inode->i_sb->s_blocksize == PAGE_SIZE)) {
2036			/*
2037			 * For memory cleaning there's no point in writing only
2038			 * some buffers. So just bail out. Warn if we came here
2039			 * from direct reclaim.
2040			 */
2041			WARN_ON_ONCE((current->flags & (PF_MEMALLOC|PF_KSWAPD))
2042							== PF_MEMALLOC);
2043			unlock_page(page);
2044			return 0;
2045		}
2046		keep_towrite = true;
2047	}
2048
2049	if (PageChecked(page) && ext4_should_journal_data(inode))
2050		/*
2051		 * It's mmapped pagecache.  Add buffers and journal it.  There
2052		 * doesn't seem much point in redirtying the page here.
2053		 */
2054		return __ext4_journalled_writepage(page, len);
2055
2056	ext4_io_submit_init(&io_submit, wbc);
2057	io_submit.io_end = ext4_init_io_end(inode, GFP_NOFS);
2058	if (!io_submit.io_end) {
2059		redirty_page_for_writepage(wbc, page);
2060		unlock_page(page);
2061		return -ENOMEM;
2062	}
2063	ret = ext4_bio_write_page(&io_submit, page, len, wbc, keep_towrite);
2064	ext4_io_submit(&io_submit);
2065	/* Drop io_end reference we got from init */
2066	ext4_put_io_end_defer(io_submit.io_end);
2067	return ret;
2068}
2069
2070static int mpage_submit_page(struct mpage_da_data *mpd, struct page *page)
2071{
2072	int len;
2073	loff_t size = i_size_read(mpd->inode);
2074	int err;
2075
2076	BUG_ON(page->index != mpd->first_page);
2077	if (page->index == size >> PAGE_SHIFT)
2078		len = size & ~PAGE_MASK;
2079	else
2080		len = PAGE_SIZE;
2081	clear_page_dirty_for_io(page);
2082	err = ext4_bio_write_page(&mpd->io_submit, page, len, mpd->wbc, false);
2083	if (!err)
2084		mpd->wbc->nr_to_write--;
2085	mpd->first_page++;
2086
2087	return err;
2088}
2089
2090#define BH_FLAGS ((1 << BH_Unwritten) | (1 << BH_Delay))
2091
2092/*
2093 * mballoc gives us at most this number of blocks...
2094 * XXX: That seems to be only a limitation of ext4_mb_normalize_request().
2095 * The rest of mballoc seems to handle chunks up to full group size.
2096 */
2097#define MAX_WRITEPAGES_EXTENT_LEN 2048
2098
2099/*
2100 * mpage_add_bh_to_extent - try to add bh to extent of blocks to map
2101 *
2102 * @mpd - extent of blocks
2103 * @lblk - logical number of the block in the file
2104 * @bh - buffer head we want to add to the extent
2105 *
2106 * The function is used to collect contig. blocks in the same state. If the
2107 * buffer doesn't require mapping for writeback and we haven't started the
2108 * extent of buffers to map yet, the function returns 'true' immediately - the
2109 * caller can write the buffer right away. Otherwise the function returns true
2110 * if the block has been added to the extent, false if the block couldn't be
2111 * added.
2112 */
2113static bool mpage_add_bh_to_extent(struct mpage_da_data *mpd, ext4_lblk_t lblk,
2114				   struct buffer_head *bh)
2115{
2116	struct ext4_map_blocks *map = &mpd->map;
2117
2118	/* Buffer that doesn't need mapping for writeback? */
2119	if (!buffer_dirty(bh) || !buffer_mapped(bh) ||
2120	    (!buffer_delay(bh) && !buffer_unwritten(bh))) {
2121		/* So far no extent to map => we write the buffer right away */
2122		if (map->m_len == 0)
2123			return true;
2124		return false;
2125	}
2126
2127	/* First block in the extent? */
2128	if (map->m_len == 0) {
2129		map->m_lblk = lblk;
2130		map->m_len = 1;
2131		map->m_flags = bh->b_state & BH_FLAGS;
2132		return true;
2133	}
2134
2135	/* Don't go larger than mballoc is willing to allocate */
2136	if (map->m_len >= MAX_WRITEPAGES_EXTENT_LEN)
2137		return false;
2138
2139	/* Can we merge the block to our big extent? */
2140	if (lblk == map->m_lblk + map->m_len &&
2141	    (bh->b_state & BH_FLAGS) == map->m_flags) {
2142		map->m_len++;
2143		return true;
2144	}
2145	return false;
2146}
2147
2148/*
2149 * mpage_process_page_bufs - submit page buffers for IO or add them to extent
2150 *
2151 * @mpd - extent of blocks for mapping
2152 * @head - the first buffer in the page
2153 * @bh - buffer we should start processing from
2154 * @lblk - logical number of the block in the file corresponding to @bh
2155 *
2156 * Walk through page buffers from @bh upto @head (exclusive) and either submit
2157 * the page for IO if all buffers in this page were mapped and there's no
2158 * accumulated extent of buffers to map or add buffers in the page to the
2159 * extent of buffers to map. The function returns 1 if the caller can continue
2160 * by processing the next page, 0 if it should stop adding buffers to the
2161 * extent to map because we cannot extend it anymore. It can also return value
2162 * < 0 in case of error during IO submission.
2163 */
2164static int mpage_process_page_bufs(struct mpage_da_data *mpd,
2165				   struct buffer_head *head,
2166				   struct buffer_head *bh,
2167				   ext4_lblk_t lblk)
2168{
2169	struct inode *inode = mpd->inode;
2170	int err;
2171	ext4_lblk_t blocks = (i_size_read(inode) + (1 << inode->i_blkbits) - 1)
2172							>> inode->i_blkbits;
2173
2174	do {
2175		BUG_ON(buffer_locked(bh));
2176
2177		if (lblk >= blocks || !mpage_add_bh_to_extent(mpd, lblk, bh)) {
2178			/* Found extent to map? */
2179			if (mpd->map.m_len)
2180				return 0;
2181			/* Everything mapped so far and we hit EOF */
2182			break;
2183		}
2184	} while (lblk++, (bh = bh->b_this_page) != head);
2185	/* So far everything mapped? Submit the page for IO. */
2186	if (mpd->map.m_len == 0) {
2187		err = mpage_submit_page(mpd, head->b_page);
2188		if (err < 0)
2189			return err;
2190	}
2191	return lblk < blocks;
2192}
2193
2194/*
2195 * mpage_map_buffers - update buffers corresponding to changed extent and
2196 *		       submit fully mapped pages for IO
2197 *
2198 * @mpd - description of extent to map, on return next extent to map
2199 *
2200 * Scan buffers corresponding to changed extent (we expect corresponding pages
2201 * to be already locked) and update buffer state according to new extent state.
2202 * We map delalloc buffers to their physical location, clear unwritten bits,
2203 * and mark buffers as uninit when we perform writes to unwritten extents
2204 * and do extent conversion after IO is finished. If the last page is not fully
2205 * mapped, we update @map to the next extent in the last page that needs
2206 * mapping. Otherwise we submit the page for IO.
2207 */
2208static int mpage_map_and_submit_buffers(struct mpage_da_data *mpd)
2209{
2210	struct pagevec pvec;
2211	int nr_pages, i;
2212	struct inode *inode = mpd->inode;
2213	struct buffer_head *head, *bh;
2214	int bpp_bits = PAGE_SHIFT - inode->i_blkbits;
2215	pgoff_t start, end;
2216	ext4_lblk_t lblk;
2217	sector_t pblock;
2218	int err;
2219
2220	start = mpd->map.m_lblk >> bpp_bits;
2221	end = (mpd->map.m_lblk + mpd->map.m_len - 1) >> bpp_bits;
2222	lblk = start << bpp_bits;
2223	pblock = mpd->map.m_pblk;
2224
2225	pagevec_init(&pvec, 0);
2226	while (start <= end) {
2227		nr_pages = pagevec_lookup(&pvec, inode->i_mapping, start,
2228					  PAGEVEC_SIZE);
2229		if (nr_pages == 0)
2230			break;
2231		for (i = 0; i < nr_pages; i++) {
2232			struct page *page = pvec.pages[i];
2233
2234			if (page->index > end)
2235				break;
2236			/* Up to 'end' pages must be contiguous */
2237			BUG_ON(page->index != start);
2238			bh = head = page_buffers(page);
2239			do {
2240				if (lblk < mpd->map.m_lblk)
2241					continue;
2242				if (lblk >= mpd->map.m_lblk + mpd->map.m_len) {
2243					/*
2244					 * Buffer after end of mapped extent.
2245					 * Find next buffer in the page to map.
2246					 */
2247					mpd->map.m_len = 0;
2248					mpd->map.m_flags = 0;
2249					/*
2250					 * FIXME: If dioread_nolock supports
2251					 * blocksize < pagesize, we need to make
2252					 * sure we add size mapped so far to
2253					 * io_end->size as the following call
2254					 * can submit the page for IO.
2255					 */
2256					err = mpage_process_page_bufs(mpd, head,
2257								      bh, lblk);
2258					pagevec_release(&pvec);
2259					if (err > 0)
2260						err = 0;
2261					return err;
2262				}
2263				if (buffer_delay(bh)) {
2264					clear_buffer_delay(bh);
2265					bh->b_blocknr = pblock++;
2266				}
2267				clear_buffer_unwritten(bh);
2268			} while (lblk++, (bh = bh->b_this_page) != head);
2269
2270			/*
2271			 * FIXME: This is going to break if dioread_nolock
2272			 * supports blocksize < pagesize as we will try to
2273			 * convert potentially unmapped parts of inode.
2274			 */
2275			mpd->io_submit.io_end->size += PAGE_SIZE;
2276			/* Page fully mapped - let IO run! */
2277			err = mpage_submit_page(mpd, page);
2278			if (err < 0) {
2279				pagevec_release(&pvec);
2280				return err;
2281			}
2282			start++;
2283		}
2284		pagevec_release(&pvec);
2285	}
2286	/* Extent fully mapped and matches with page boundary. We are done. */
2287	mpd->map.m_len = 0;
2288	mpd->map.m_flags = 0;
2289	return 0;
2290}
2291
2292static int mpage_map_one_extent(handle_t *handle, struct mpage_da_data *mpd)
2293{
2294	struct inode *inode = mpd->inode;
2295	struct ext4_map_blocks *map = &mpd->map;
2296	int get_blocks_flags;
2297	int err, dioread_nolock;
2298
2299	trace_ext4_da_write_pages_extent(inode, map);
2300	/*
2301	 * Call ext4_map_blocks() to allocate any delayed allocation blocks, or
2302	 * to convert an unwritten extent to be initialized (in the case
2303	 * where we have written into one or more preallocated blocks).  It is
2304	 * possible that we're going to need more metadata blocks than
2305	 * previously reserved. However we must not fail because we're in
2306	 * writeback and there is nothing we can do about it so it might result
2307	 * in data loss.  So use reserved blocks to allocate metadata if
2308	 * possible.
2309	 *
2310	 * We pass in the magic EXT4_GET_BLOCKS_DELALLOC_RESERVE if
2311	 * the blocks in question are delalloc blocks.  This indicates
2312	 * that the blocks and quotas has already been checked when
2313	 * the data was copied into the page cache.
 
 
2314	 */
2315	get_blocks_flags = EXT4_GET_BLOCKS_CREATE |
2316			   EXT4_GET_BLOCKS_METADATA_NOFAIL;
2317	dioread_nolock = ext4_should_dioread_nolock(inode);
2318	if (dioread_nolock)
2319		get_blocks_flags |= EXT4_GET_BLOCKS_IO_CREATE_EXT;
2320	if (map->m_flags & (1 << BH_Delay))
2321		get_blocks_flags |= EXT4_GET_BLOCKS_DELALLOC_RESERVE;
2322
2323	err = ext4_map_blocks(handle, inode, map, get_blocks_flags);
2324	if (err < 0)
2325		return err;
2326	if (dioread_nolock && (map->m_flags & EXT4_MAP_UNWRITTEN)) {
2327		if (!mpd->io_submit.io_end->handle &&
2328		    ext4_handle_valid(handle)) {
2329			mpd->io_submit.io_end->handle = handle->h_rsv_handle;
2330			handle->h_rsv_handle = NULL;
2331		}
2332		ext4_set_io_unwritten_flag(inode, mpd->io_submit.io_end);
2333	}
2334
2335	BUG_ON(map->m_len == 0);
2336	if (map->m_flags & EXT4_MAP_NEW) {
2337		struct block_device *bdev = inode->i_sb->s_bdev;
2338		int i;
2339
2340		for (i = 0; i < map->m_len; i++)
2341			unmap_underlying_metadata(bdev, map->m_pblk + i);
2342	}
2343	return 0;
2344}
2345
2346/*
2347 * mpage_map_and_submit_extent - map extent starting at mpd->lblk of length
2348 *				 mpd->len and submit pages underlying it for IO
2349 *
2350 * @handle - handle for journal operations
2351 * @mpd - extent to map
2352 * @give_up_on_write - we set this to true iff there is a fatal error and there
2353 *                     is no hope of writing the data. The caller should discard
2354 *                     dirty pages to avoid infinite loops.
2355 *
2356 * The function maps extent starting at mpd->lblk of length mpd->len. If it is
2357 * delayed, blocks are allocated, if it is unwritten, we may need to convert
2358 * them to initialized or split the described range from larger unwritten
2359 * extent. Note that we need not map all the described range since allocation
2360 * can return less blocks or the range is covered by more unwritten extents. We
2361 * cannot map more because we are limited by reserved transaction credits. On
2362 * the other hand we always make sure that the last touched page is fully
2363 * mapped so that it can be written out (and thus forward progress is
2364 * guaranteed). After mapping we submit all mapped pages for IO.
2365 */
2366static int mpage_map_and_submit_extent(handle_t *handle,
2367				       struct mpage_da_data *mpd,
2368				       bool *give_up_on_write)
2369{
2370	struct inode *inode = mpd->inode;
2371	struct ext4_map_blocks *map = &mpd->map;
2372	int err;
2373	loff_t disksize;
2374	int progress = 0;
2375
2376	mpd->io_submit.io_end->offset =
2377				((loff_t)map->m_lblk) << inode->i_blkbits;
2378	do {
2379		err = mpage_map_one_extent(handle, mpd);
2380		if (err < 0) {
2381			struct super_block *sb = inode->i_sb;
2382
2383			if (EXT4_SB(sb)->s_mount_flags & EXT4_MF_FS_ABORTED)
2384				goto invalidate_dirty_pages;
2385			/*
2386			 * Let the uper layers retry transient errors.
2387			 * In the case of ENOSPC, if ext4_count_free_blocks()
2388			 * is non-zero, a commit should free up blocks.
2389			 */
2390			if ((err == -ENOMEM) ||
2391			    (err == -ENOSPC && ext4_count_free_clusters(sb))) {
2392				if (progress)
2393					goto update_disksize;
2394				return err;
2395			}
2396			ext4_msg(sb, KERN_CRIT,
2397				 "Delayed block allocation failed for "
2398				 "inode %lu at logical offset %llu with"
2399				 " max blocks %u with error %d",
2400				 inode->i_ino,
2401				 (unsigned long long)map->m_lblk,
2402				 (unsigned)map->m_len, -err);
2403			ext4_msg(sb, KERN_CRIT,
2404				 "This should not happen!! Data will "
2405				 "be lost\n");
2406			if (err == -ENOSPC)
2407				ext4_print_free_blocks(inode);
2408		invalidate_dirty_pages:
2409			*give_up_on_write = true;
2410			return err;
2411		}
2412		progress = 1;
2413		/*
2414		 * Update buffer state, submit mapped pages, and get us new
2415		 * extent to map
2416		 */
2417		err = mpage_map_and_submit_buffers(mpd);
2418		if (err < 0)
2419			goto update_disksize;
2420	} while (map->m_len);
2421
2422update_disksize:
2423	/*
2424	 * Update on-disk size after IO is submitted.  Races with
2425	 * truncate are avoided by checking i_size under i_data_sem.
2426	 */
2427	disksize = ((loff_t)mpd->first_page) << PAGE_SHIFT;
2428	if (disksize > EXT4_I(inode)->i_disksize) {
2429		int err2;
2430		loff_t i_size;
2431
2432		down_write(&EXT4_I(inode)->i_data_sem);
2433		i_size = i_size_read(inode);
2434		if (disksize > i_size)
2435			disksize = i_size;
2436		if (disksize > EXT4_I(inode)->i_disksize)
2437			EXT4_I(inode)->i_disksize = disksize;
2438		err2 = ext4_mark_inode_dirty(handle, inode);
2439		up_write(&EXT4_I(inode)->i_data_sem);
2440		if (err2)
2441			ext4_error(inode->i_sb,
2442				   "Failed to mark inode %lu dirty",
2443				   inode->i_ino);
2444		if (!err)
2445			err = err2;
2446	}
2447	return err;
2448}
2449
2450/*
2451 * Calculate the total number of credits to reserve for one writepages
2452 * iteration. This is called from ext4_writepages(). We map an extent of
2453 * up to MAX_WRITEPAGES_EXTENT_LEN blocks and then we go on and finish mapping
2454 * the last partial page. So in total we can map MAX_WRITEPAGES_EXTENT_LEN +
2455 * bpp - 1 blocks in bpp different extents.
2456 */
2457static int ext4_da_writepages_trans_blocks(struct inode *inode)
2458{
2459	int bpp = ext4_journal_blocks_per_page(inode);
2460
2461	return ext4_meta_trans_blocks(inode,
2462				MAX_WRITEPAGES_EXTENT_LEN + bpp - 1, bpp);
2463}
2464
2465/*
2466 * mpage_prepare_extent_to_map - find & lock contiguous range of dirty pages
2467 * 				 and underlying extent to map
2468 *
2469 * @mpd - where to look for pages
2470 *
2471 * Walk dirty pages in the mapping. If they are fully mapped, submit them for
2472 * IO immediately. When we find a page which isn't mapped we start accumulating
2473 * extent of buffers underlying these pages that needs mapping (formed by
2474 * either delayed or unwritten buffers). We also lock the pages containing
2475 * these buffers. The extent found is returned in @mpd structure (starting at
2476 * mpd->lblk with length mpd->len blocks).
2477 *
2478 * Note that this function can attach bios to one io_end structure which are
2479 * neither logically nor physically contiguous. Although it may seem as an
2480 * unnecessary complication, it is actually inevitable in blocksize < pagesize
2481 * case as we need to track IO to all buffers underlying a page in one io_end.
2482 */
2483static int mpage_prepare_extent_to_map(struct mpage_da_data *mpd)
2484{
2485	struct address_space *mapping = mpd->inode->i_mapping;
2486	struct pagevec pvec;
2487	unsigned int nr_pages;
2488	long left = mpd->wbc->nr_to_write;
2489	pgoff_t index = mpd->first_page;
2490	pgoff_t end = mpd->last_page;
2491	int tag;
2492	int i, err = 0;
2493	int blkbits = mpd->inode->i_blkbits;
2494	ext4_lblk_t lblk;
2495	struct buffer_head *head;
2496
2497	if (mpd->wbc->sync_mode == WB_SYNC_ALL || mpd->wbc->tagged_writepages)
2498		tag = PAGECACHE_TAG_TOWRITE;
2499	else
2500		tag = PAGECACHE_TAG_DIRTY;
2501
2502	pagevec_init(&pvec, 0);
2503	mpd->map.m_len = 0;
2504	mpd->next_page = index;
2505	while (index <= end) {
2506		nr_pages = pagevec_lookup_tag(&pvec, mapping, &index, tag,
2507			      min(end - index, (pgoff_t)PAGEVEC_SIZE-1) + 1);
2508		if (nr_pages == 0)
2509			goto out;
2510
2511		for (i = 0; i < nr_pages; i++) {
2512			struct page *page = pvec.pages[i];
2513
2514			/*
2515			 * At this point, the page may be truncated or
2516			 * invalidated (changing page->mapping to NULL), or
2517			 * even swizzled back from swapper_space to tmpfs file
2518			 * mapping. However, page->index will not change
2519			 * because we have a reference on the page.
2520			 */
2521			if (page->index > end)
2522				goto out;
2523
2524			/*
2525			 * Accumulated enough dirty pages? This doesn't apply
2526			 * to WB_SYNC_ALL mode. For integrity sync we have to
2527			 * keep going because someone may be concurrently
2528			 * dirtying pages, and we might have synced a lot of
2529			 * newly appeared dirty pages, but have not synced all
2530			 * of the old dirty pages.
2531			 */
2532			if (mpd->wbc->sync_mode == WB_SYNC_NONE && left <= 0)
2533				goto out;
2534
2535			/* If we can't merge this page, we are done. */
2536			if (mpd->map.m_len > 0 && mpd->next_page != page->index)
2537				goto out;
2538
2539			lock_page(page);
2540			/*
2541			 * If the page is no longer dirty, or its mapping no
2542			 * longer corresponds to inode we are writing (which
2543			 * means it has been truncated or invalidated), or the
2544			 * page is already under writeback and we are not doing
2545			 * a data integrity writeback, skip the page
2546			 */
2547			if (!PageDirty(page) ||
2548			    (PageWriteback(page) &&
2549			     (mpd->wbc->sync_mode == WB_SYNC_NONE)) ||
2550			    unlikely(page->mapping != mapping)) {
2551				unlock_page(page);
2552				continue;
2553			}
2554
2555			wait_on_page_writeback(page);
2556			BUG_ON(PageWriteback(page));
2557
2558			if (mpd->map.m_len == 0)
2559				mpd->first_page = page->index;
2560			mpd->next_page = page->index + 1;
2561			/* Add all dirty buffers to mpd */
2562			lblk = ((ext4_lblk_t)page->index) <<
2563				(PAGE_SHIFT - blkbits);
2564			head = page_buffers(page);
2565			err = mpage_process_page_bufs(mpd, head, head, lblk);
2566			if (err <= 0)
2567				goto out;
2568			err = 0;
2569			left--;
2570		}
2571		pagevec_release(&pvec);
2572		cond_resched();
2573	}
2574	return 0;
2575out:
2576	pagevec_release(&pvec);
2577	return err;
2578}
2579
2580static int __writepage(struct page *page, struct writeback_control *wbc,
2581		       void *data)
2582{
2583	struct address_space *mapping = data;
2584	int ret = ext4_writepage(page, wbc);
2585	mapping_set_error(mapping, ret);
2586	return ret;
2587}
2588
2589static int ext4_writepages(struct address_space *mapping,
2590			   struct writeback_control *wbc)
2591{
2592	pgoff_t	writeback_index = 0;
2593	long nr_to_write = wbc->nr_to_write;
2594	int range_whole = 0;
2595	int cycled = 1;
2596	handle_t *handle = NULL;
2597	struct mpage_da_data mpd;
2598	struct inode *inode = mapping->host;
2599	int needed_blocks, rsv_blocks = 0, ret = 0;
2600	struct ext4_sb_info *sbi = EXT4_SB(mapping->host->i_sb);
2601	bool done;
2602	struct blk_plug plug;
2603	bool give_up_on_write = false;
2604
2605	trace_ext4_writepages(inode, wbc);
2606
2607	if (dax_mapping(mapping))
2608		return dax_writeback_mapping_range(mapping, inode->i_sb->s_bdev,
2609						   wbc);
2610
2611	/*
2612	 * No pages to write? This is mainly a kludge to avoid starting
2613	 * a transaction for special inodes like journal inode on last iput()
2614	 * because that could violate lock ordering on umount
2615	 */
2616	if (!mapping->nrpages || !mapping_tagged(mapping, PAGECACHE_TAG_DIRTY))
2617		goto out_writepages;
2618
2619	if (ext4_should_journal_data(inode)) {
2620		struct blk_plug plug;
2621
2622		blk_start_plug(&plug);
2623		ret = write_cache_pages(mapping, wbc, __writepage, mapping);
2624		blk_finish_plug(&plug);
2625		goto out_writepages;
2626	}
2627
2628	/*
2629	 * If the filesystem has aborted, it is read-only, so return
2630	 * right away instead of dumping stack traces later on that
2631	 * will obscure the real source of the problem.  We test
2632	 * EXT4_MF_FS_ABORTED instead of sb->s_flag's MS_RDONLY because
2633	 * the latter could be true if the filesystem is mounted
2634	 * read-only, and in that case, ext4_writepages should
2635	 * *never* be called, so if that ever happens, we would want
2636	 * the stack trace.
2637	 */
2638	if (unlikely(sbi->s_mount_flags & EXT4_MF_FS_ABORTED)) {
2639		ret = -EROFS;
2640		goto out_writepages;
2641	}
2642
2643	if (ext4_should_dioread_nolock(inode)) {
2644		/*
2645		 * We may need to convert up to one extent per block in
2646		 * the page and we may dirty the inode.
2647		 */
2648		rsv_blocks = 1 + (PAGE_SIZE >> inode->i_blkbits);
2649	}
2650
2651	/*
2652	 * If we have inline data and arrive here, it means that
2653	 * we will soon create the block for the 1st page, so
2654	 * we'd better clear the inline data here.
2655	 */
2656	if (ext4_has_inline_data(inode)) {
2657		/* Just inode will be modified... */
2658		handle = ext4_journal_start(inode, EXT4_HT_INODE, 1);
2659		if (IS_ERR(handle)) {
2660			ret = PTR_ERR(handle);
2661			goto out_writepages;
2662		}
2663		BUG_ON(ext4_test_inode_state(inode,
2664				EXT4_STATE_MAY_INLINE_DATA));
2665		ext4_destroy_inline_data(handle, inode);
2666		ext4_journal_stop(handle);
2667	}
2668
2669	if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX)
2670		range_whole = 1;
2671
2672	if (wbc->range_cyclic) {
2673		writeback_index = mapping->writeback_index;
2674		if (writeback_index)
2675			cycled = 0;
2676		mpd.first_page = writeback_index;
2677		mpd.last_page = -1;
2678	} else {
2679		mpd.first_page = wbc->range_start >> PAGE_SHIFT;
2680		mpd.last_page = wbc->range_end >> PAGE_SHIFT;
2681	}
2682
2683	mpd.inode = inode;
2684	mpd.wbc = wbc;
2685	ext4_io_submit_init(&mpd.io_submit, wbc);
2686retry:
2687	if (wbc->sync_mode == WB_SYNC_ALL || wbc->tagged_writepages)
2688		tag_pages_for_writeback(mapping, mpd.first_page, mpd.last_page);
2689	done = false;
2690	blk_start_plug(&plug);
2691	while (!done && mpd.first_page <= mpd.last_page) {
2692		/* For each extent of pages we use new io_end */
2693		mpd.io_submit.io_end = ext4_init_io_end(inode, GFP_KERNEL);
2694		if (!mpd.io_submit.io_end) {
2695			ret = -ENOMEM;
2696			break;
2697		}
2698
2699		/*
2700		 * We have two constraints: We find one extent to map and we
2701		 * must always write out whole page (makes a difference when
2702		 * blocksize < pagesize) so that we don't block on IO when we
2703		 * try to write out the rest of the page. Journalled mode is
2704		 * not supported by delalloc.
2705		 */
2706		BUG_ON(ext4_should_journal_data(inode));
2707		needed_blocks = ext4_da_writepages_trans_blocks(inode);
2708
2709		/* start a new transaction */
2710		handle = ext4_journal_start_with_reserve(inode,
2711				EXT4_HT_WRITE_PAGE, needed_blocks, rsv_blocks);
2712		if (IS_ERR(handle)) {
2713			ret = PTR_ERR(handle);
2714			ext4_msg(inode->i_sb, KERN_CRIT, "%s: jbd2_start: "
2715			       "%ld pages, ino %lu; err %d", __func__,
2716				wbc->nr_to_write, inode->i_ino, ret);
2717			/* Release allocated io_end */
2718			ext4_put_io_end(mpd.io_submit.io_end);
2719			break;
2720		}
2721
2722		trace_ext4_da_write_pages(inode, mpd.first_page, mpd.wbc);
2723		ret = mpage_prepare_extent_to_map(&mpd);
2724		if (!ret) {
2725			if (mpd.map.m_len)
2726				ret = mpage_map_and_submit_extent(handle, &mpd,
2727					&give_up_on_write);
2728			else {
2729				/*
2730				 * We scanned the whole range (or exhausted
2731				 * nr_to_write), submitted what was mapped and
2732				 * didn't find anything needing mapping. We are
2733				 * done.
2734				 */
2735				done = true;
2736			}
2737		}
2738		ext4_journal_stop(handle);
2739		/* Submit prepared bio */
2740		ext4_io_submit(&mpd.io_submit);
2741		/* Unlock pages we didn't use */
2742		mpage_release_unused_pages(&mpd, give_up_on_write);
2743		/* Drop our io_end reference we got from init */
2744		ext4_put_io_end(mpd.io_submit.io_end);
2745
2746		if (ret == -ENOSPC && sbi->s_journal) {
2747			/*
2748			 * Commit the transaction which would
2749			 * free blocks released in the transaction
2750			 * and try again
2751			 */
2752			jbd2_journal_force_commit_nested(sbi->s_journal);
2753			ret = 0;
2754			continue;
2755		}
2756		/* Fatal error - ENOMEM, EIO... */
2757		if (ret)
2758			break;
2759	}
2760	blk_finish_plug(&plug);
2761	if (!ret && !cycled && wbc->nr_to_write > 0) {
2762		cycled = 1;
2763		mpd.last_page = writeback_index - 1;
2764		mpd.first_page = 0;
2765		goto retry;
2766	}
2767
2768	/* Update index */
2769	if (wbc->range_cyclic || (range_whole && wbc->nr_to_write > 0))
2770		/*
2771		 * Set the writeback_index so that range_cyclic
2772		 * mode will write it back later
2773		 */
2774		mapping->writeback_index = mpd.first_page;
2775
2776out_writepages:
2777	trace_ext4_writepages_result(inode, wbc, ret,
2778				     nr_to_write - wbc->nr_to_write);
2779	return ret;
2780}
2781
2782static int ext4_nonda_switch(struct super_block *sb)
2783{
2784	s64 free_clusters, dirty_clusters;
2785	struct ext4_sb_info *sbi = EXT4_SB(sb);
2786
2787	/*
2788	 * switch to non delalloc mode if we are running low
2789	 * on free block. The free block accounting via percpu
2790	 * counters can get slightly wrong with percpu_counter_batch getting
2791	 * accumulated on each CPU without updating global counters
2792	 * Delalloc need an accurate free block accounting. So switch
2793	 * to non delalloc when we are near to error range.
2794	 */
2795	free_clusters =
2796		percpu_counter_read_positive(&sbi->s_freeclusters_counter);
2797	dirty_clusters =
2798		percpu_counter_read_positive(&sbi->s_dirtyclusters_counter);
2799	/*
2800	 * Start pushing delalloc when 1/2 of free blocks are dirty.
2801	 */
2802	if (dirty_clusters && (free_clusters < 2 * dirty_clusters))
2803		try_to_writeback_inodes_sb(sb, WB_REASON_FS_FREE_SPACE);
2804
2805	if (2 * free_clusters < 3 * dirty_clusters ||
2806	    free_clusters < (dirty_clusters + EXT4_FREECLUSTERS_WATERMARK)) {
2807		/*
2808		 * free block count is less than 150% of dirty blocks
2809		 * or free blocks is less than watermark
2810		 */
2811		return 1;
2812	}
2813	return 0;
2814}
2815
2816/* We always reserve for an inode update; the superblock could be there too */
2817static int ext4_da_write_credits(struct inode *inode, loff_t pos, unsigned len)
2818{
2819	if (likely(ext4_has_feature_large_file(inode->i_sb)))
2820		return 1;
2821
2822	if (pos + len <= 0x7fffffffULL)
2823		return 1;
2824
2825	/* We might need to update the superblock to set LARGE_FILE */
2826	return 2;
2827}
2828
2829static int ext4_da_write_begin(struct file *file, struct address_space *mapping,
2830			       loff_t pos, unsigned len, unsigned flags,
2831			       struct page **pagep, void **fsdata)
2832{
2833	int ret, retries = 0;
2834	struct page *page;
2835	pgoff_t index;
2836	struct inode *inode = mapping->host;
2837	handle_t *handle;
2838
2839	index = pos >> PAGE_SHIFT;
2840
2841	if (ext4_nonda_switch(inode->i_sb)) {
2842		*fsdata = (void *)FALL_BACK_TO_NONDELALLOC;
2843		return ext4_write_begin(file, mapping, pos,
2844					len, flags, pagep, fsdata);
2845	}
2846	*fsdata = (void *)0;
2847	trace_ext4_da_write_begin(inode, pos, len, flags);
2848
2849	if (ext4_test_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA)) {
2850		ret = ext4_da_write_inline_data_begin(mapping, inode,
2851						      pos, len, flags,
2852						      pagep, fsdata);
2853		if (ret < 0)
2854			return ret;
2855		if (ret == 1)
2856			return 0;
2857	}
2858
2859	/*
2860	 * grab_cache_page_write_begin() can take a long time if the
2861	 * system is thrashing due to memory pressure, or if the page
2862	 * is being written back.  So grab it first before we start
2863	 * the transaction handle.  This also allows us to allocate
2864	 * the page (if needed) without using GFP_NOFS.
2865	 */
2866retry_grab:
2867	page = grab_cache_page_write_begin(mapping, index, flags);
2868	if (!page)
2869		return -ENOMEM;
2870	unlock_page(page);
2871
2872	/*
2873	 * With delayed allocation, we don't log the i_disksize update
2874	 * if there is delayed block allocation. But we still need
2875	 * to journalling the i_disksize update if writes to the end
2876	 * of file which has an already mapped buffer.
2877	 */
2878retry_journal:
2879	handle = ext4_journal_start(inode, EXT4_HT_WRITE_PAGE,
2880				ext4_da_write_credits(inode, pos, len));
2881	if (IS_ERR(handle)) {
2882		put_page(page);
2883		return PTR_ERR(handle);
2884	}
2885
2886	lock_page(page);
2887	if (page->mapping != mapping) {
2888		/* The page got truncated from under us */
2889		unlock_page(page);
2890		put_page(page);
2891		ext4_journal_stop(handle);
2892		goto retry_grab;
2893	}
2894	/* In case writeback began while the page was unlocked */
2895	wait_for_stable_page(page);
2896
2897#ifdef CONFIG_EXT4_FS_ENCRYPTION
2898	ret = ext4_block_write_begin(page, pos, len,
2899				     ext4_da_get_block_prep);
2900#else
2901	ret = __block_write_begin(page, pos, len, ext4_da_get_block_prep);
2902#endif
2903	if (ret < 0) {
2904		unlock_page(page);
2905		ext4_journal_stop(handle);
2906		/*
2907		 * block_write_begin may have instantiated a few blocks
2908		 * outside i_size.  Trim these off again. Don't need
2909		 * i_size_read because we hold i_mutex.
2910		 */
2911		if (pos + len > inode->i_size)
2912			ext4_truncate_failed_write(inode);
2913
2914		if (ret == -ENOSPC &&
2915		    ext4_should_retry_alloc(inode->i_sb, &retries))
2916			goto retry_journal;
2917
2918		put_page(page);
2919		return ret;
2920	}
2921
2922	*pagep = page;
2923	return ret;
2924}
2925
2926/*
2927 * Check if we should update i_disksize
2928 * when write to the end of file but not require block allocation
2929 */
2930static int ext4_da_should_update_i_disksize(struct page *page,
2931					    unsigned long offset)
2932{
2933	struct buffer_head *bh;
2934	struct inode *inode = page->mapping->host;
2935	unsigned int idx;
2936	int i;
2937
2938	bh = page_buffers(page);
2939	idx = offset >> inode->i_blkbits;
2940
2941	for (i = 0; i < idx; i++)
2942		bh = bh->b_this_page;
2943
2944	if (!buffer_mapped(bh) || (buffer_delay(bh)) || buffer_unwritten(bh))
2945		return 0;
2946	return 1;
2947}
2948
2949static int ext4_da_write_end(struct file *file,
2950			     struct address_space *mapping,
2951			     loff_t pos, unsigned len, unsigned copied,
2952			     struct page *page, void *fsdata)
2953{
2954	struct inode *inode = mapping->host;
2955	int ret = 0, ret2;
2956	handle_t *handle = ext4_journal_current_handle();
2957	loff_t new_i_size;
2958	unsigned long start, end;
2959	int write_mode = (int)(unsigned long)fsdata;
2960
2961	if (write_mode == FALL_BACK_TO_NONDELALLOC)
2962		return ext4_write_end(file, mapping, pos,
2963				      len, copied, page, fsdata);
2964
2965	trace_ext4_da_write_end(inode, pos, len, copied);
2966	start = pos & (PAGE_SIZE - 1);
2967	end = start + copied - 1;
2968
2969	/*
2970	 * generic_write_end() will run mark_inode_dirty() if i_size
2971	 * changes.  So let's piggyback the i_disksize mark_inode_dirty
2972	 * into that.
2973	 */
2974	new_i_size = pos + copied;
2975	if (copied && new_i_size > EXT4_I(inode)->i_disksize) {
2976		if (ext4_has_inline_data(inode) ||
2977		    ext4_da_should_update_i_disksize(page, end)) {
2978			ext4_update_i_disksize(inode, new_i_size);
 
 
 
2979			/* We need to mark inode dirty even if
2980			 * new_i_size is less that inode->i_size
2981			 * bu greater than i_disksize.(hint delalloc)
2982			 */
2983			ext4_mark_inode_dirty(handle, inode);
2984		}
2985	}
2986
2987	if (write_mode != CONVERT_INLINE_DATA &&
2988	    ext4_test_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA) &&
2989	    ext4_has_inline_data(inode))
2990		ret2 = ext4_da_write_inline_data_end(inode, pos, len, copied,
2991						     page);
2992	else
2993		ret2 = generic_write_end(file, mapping, pos, len, copied,
2994							page, fsdata);
2995
2996	copied = ret2;
2997	if (ret2 < 0)
2998		ret = ret2;
2999	ret2 = ext4_journal_stop(handle);
3000	if (!ret)
3001		ret = ret2;
3002
3003	return ret ? ret : copied;
3004}
3005
3006static void ext4_da_invalidatepage(struct page *page, unsigned int offset,
3007				   unsigned int length)
3008{
3009	/*
3010	 * Drop reserved blocks
3011	 */
3012	BUG_ON(!PageLocked(page));
3013	if (!page_has_buffers(page))
3014		goto out;
3015
3016	ext4_da_page_release_reservation(page, offset, length);
3017
3018out:
3019	ext4_invalidatepage(page, offset, length);
3020
3021	return;
3022}
3023
3024/*
3025 * Force all delayed allocation blocks to be allocated for a given inode.
3026 */
3027int ext4_alloc_da_blocks(struct inode *inode)
3028{
3029	trace_ext4_alloc_da_blocks(inode);
3030
3031	if (!EXT4_I(inode)->i_reserved_data_blocks)
 
3032		return 0;
3033
3034	/*
3035	 * We do something simple for now.  The filemap_flush() will
3036	 * also start triggering a write of the data blocks, which is
3037	 * not strictly speaking necessary (and for users of
3038	 * laptop_mode, not even desirable).  However, to do otherwise
3039	 * would require replicating code paths in:
3040	 *
3041	 * ext4_writepages() ->
3042	 *    write_cache_pages() ---> (via passed in callback function)
3043	 *        __mpage_da_writepage() -->
3044	 *           mpage_add_bh_to_extent()
3045	 *           mpage_da_map_blocks()
3046	 *
3047	 * The problem is that write_cache_pages(), located in
3048	 * mm/page-writeback.c, marks pages clean in preparation for
3049	 * doing I/O, which is not desirable if we're not planning on
3050	 * doing I/O at all.
3051	 *
3052	 * We could call write_cache_pages(), and then redirty all of
3053	 * the pages by calling redirty_page_for_writepage() but that
3054	 * would be ugly in the extreme.  So instead we would need to
3055	 * replicate parts of the code in the above functions,
3056	 * simplifying them because we wouldn't actually intend to
3057	 * write out the pages, but rather only collect contiguous
3058	 * logical block extents, call the multi-block allocator, and
3059	 * then update the buffer heads with the block allocations.
3060	 *
3061	 * For now, though, we'll cheat by calling filemap_flush(),
3062	 * which will map the blocks, and start the I/O, but not
3063	 * actually wait for the I/O to complete.
3064	 */
3065	return filemap_flush(inode->i_mapping);
3066}
3067
3068/*
3069 * bmap() is special.  It gets used by applications such as lilo and by
3070 * the swapper to find the on-disk block of a specific piece of data.
3071 *
3072 * Naturally, this is dangerous if the block concerned is still in the
3073 * journal.  If somebody makes a swapfile on an ext4 data-journaling
3074 * filesystem and enables swap, then they may get a nasty shock when the
3075 * data getting swapped to that swapfile suddenly gets overwritten by
3076 * the original zero's written out previously to the journal and
3077 * awaiting writeback in the kernel's buffer cache.
3078 *
3079 * So, if we see any bmap calls here on a modified, data-journaled file,
3080 * take extra steps to flush any blocks which might be in the cache.
3081 */
3082static sector_t ext4_bmap(struct address_space *mapping, sector_t block)
3083{
3084	struct inode *inode = mapping->host;
3085	journal_t *journal;
3086	int err;
3087
3088	/*
3089	 * We can get here for an inline file via the FIBMAP ioctl
3090	 */
3091	if (ext4_has_inline_data(inode))
3092		return 0;
3093
3094	if (mapping_tagged(mapping, PAGECACHE_TAG_DIRTY) &&
3095			test_opt(inode->i_sb, DELALLOC)) {
3096		/*
3097		 * With delalloc we want to sync the file
3098		 * so that we can make sure we allocate
3099		 * blocks for file
3100		 */
3101		filemap_write_and_wait(mapping);
3102	}
3103
3104	if (EXT4_JOURNAL(inode) &&
3105	    ext4_test_inode_state(inode, EXT4_STATE_JDATA)) {
3106		/*
3107		 * This is a REALLY heavyweight approach, but the use of
3108		 * bmap on dirty files is expected to be extremely rare:
3109		 * only if we run lilo or swapon on a freshly made file
3110		 * do we expect this to happen.
3111		 *
3112		 * (bmap requires CAP_SYS_RAWIO so this does not
3113		 * represent an unprivileged user DOS attack --- we'd be
3114		 * in trouble if mortal users could trigger this path at
3115		 * will.)
3116		 *
3117		 * NB. EXT4_STATE_JDATA is not set on files other than
3118		 * regular files.  If somebody wants to bmap a directory
3119		 * or symlink and gets confused because the buffer
3120		 * hasn't yet been flushed to disk, they deserve
3121		 * everything they get.
3122		 */
3123
3124		ext4_clear_inode_state(inode, EXT4_STATE_JDATA);
3125		journal = EXT4_JOURNAL(inode);
3126		jbd2_journal_lock_updates(journal);
3127		err = jbd2_journal_flush(journal);
3128		jbd2_journal_unlock_updates(journal);
3129
3130		if (err)
3131			return 0;
3132	}
3133
3134	return generic_block_bmap(mapping, block, ext4_get_block);
3135}
3136
3137static int ext4_readpage(struct file *file, struct page *page)
3138{
3139	int ret = -EAGAIN;
3140	struct inode *inode = page->mapping->host;
3141
3142	trace_ext4_readpage(page);
3143
3144	if (ext4_has_inline_data(inode))
3145		ret = ext4_readpage_inline(inode, page);
3146
3147	if (ret == -EAGAIN)
3148		return ext4_mpage_readpages(page->mapping, NULL, page, 1);
3149
3150	return ret;
3151}
3152
3153static int
3154ext4_readpages(struct file *file, struct address_space *mapping,
3155		struct list_head *pages, unsigned nr_pages)
3156{
3157	struct inode *inode = mapping->host;
3158
3159	/* If the file has inline data, no need to do readpages. */
3160	if (ext4_has_inline_data(inode))
3161		return 0;
3162
3163	return ext4_mpage_readpages(mapping, pages, NULL, nr_pages);
3164}
3165
3166static void ext4_invalidatepage(struct page *page, unsigned int offset,
3167				unsigned int length)
3168{
3169	trace_ext4_invalidatepage(page, offset, length);
3170
3171	/* No journalling happens on data buffers when this function is used */
3172	WARN_ON(page_has_buffers(page) && buffer_jbd(page_buffers(page)));
3173
3174	block_invalidatepage(page, offset, length);
3175}
3176
3177static int __ext4_journalled_invalidatepage(struct page *page,
3178					    unsigned int offset,
3179					    unsigned int length)
3180{
3181	journal_t *journal = EXT4_JOURNAL(page->mapping->host);
3182
3183	trace_ext4_journalled_invalidatepage(page, offset, length);
3184
3185	/*
3186	 * If it's a full truncate we just forget about the pending dirtying
3187	 */
3188	if (offset == 0 && length == PAGE_SIZE)
3189		ClearPageChecked(page);
3190
3191	return jbd2_journal_invalidatepage(journal, page, offset, length);
3192}
3193
3194/* Wrapper for aops... */
3195static void ext4_journalled_invalidatepage(struct page *page,
3196					   unsigned int offset,
3197					   unsigned int length)
3198{
3199	WARN_ON(__ext4_journalled_invalidatepage(page, offset, length) < 0);
3200}
3201
3202static int ext4_releasepage(struct page *page, gfp_t wait)
3203{
3204	journal_t *journal = EXT4_JOURNAL(page->mapping->host);
3205
3206	trace_ext4_releasepage(page);
3207
3208	/* Page has dirty journalled data -> cannot release */
3209	if (PageChecked(page))
3210		return 0;
3211	if (journal)
3212		return jbd2_journal_try_to_free_buffers(journal, page, wait);
3213	else
3214		return try_to_free_buffers(page);
3215}
3216
3217#ifdef CONFIG_FS_DAX
3218int ext4_dax_mmap_get_block(struct inode *inode, sector_t iblock,
3219			    struct buffer_head *bh_result, int create)
 
 
 
 
3220{
3221	int ret, err;
3222	int credits;
3223	struct ext4_map_blocks map;
3224	handle_t *handle = NULL;
3225	int flags = 0;
3226
3227	ext4_debug("ext4_dax_mmap_get_block: inode %lu, create flag %d\n",
3228		   inode->i_ino, create);
3229	map.m_lblk = iblock;
3230	map.m_len = bh_result->b_size >> inode->i_blkbits;
3231	credits = ext4_chunk_trans_blocks(inode, map.m_len);
3232	if (create) {
3233		flags |= EXT4_GET_BLOCKS_PRE_IO | EXT4_GET_BLOCKS_CREATE_ZERO;
3234		handle = ext4_journal_start(inode, EXT4_HT_MAP_BLOCKS, credits);
3235		if (IS_ERR(handle)) {
3236			ret = PTR_ERR(handle);
3237			return ret;
3238		}
3239	}
3240
3241	ret = ext4_map_blocks(handle, inode, &map, flags);
3242	if (create) {
3243		err = ext4_journal_stop(handle);
3244		if (ret >= 0 && err < 0)
3245			ret = err;
3246	}
3247	if (ret <= 0)
3248		goto out;
3249	if (map.m_flags & EXT4_MAP_UNWRITTEN) {
3250		int err2;
3251
3252		/*
3253		 * We are protected by i_mmap_sem so we know block cannot go
3254		 * away from under us even though we dropped i_data_sem.
3255		 * Convert extent to written and write zeros there.
3256		 *
3257		 * Note: We may get here even when create == 0.
3258		 */
3259		handle = ext4_journal_start(inode, EXT4_HT_MAP_BLOCKS, credits);
3260		if (IS_ERR(handle)) {
3261			ret = PTR_ERR(handle);
3262			goto out;
3263		}
3264
3265		err = ext4_map_blocks(handle, inode, &map,
3266		      EXT4_GET_BLOCKS_CONVERT | EXT4_GET_BLOCKS_CREATE_ZERO);
3267		if (err < 0)
3268			ret = err;
3269		err2 = ext4_journal_stop(handle);
3270		if (err2 < 0 && ret > 0)
3271			ret = err2;
3272	}
3273out:
3274	WARN_ON_ONCE(ret == 0 && create);
3275	if (ret > 0) {
3276		map_bh(bh_result, inode->i_sb, map.m_pblk);
3277		/*
3278		 * At least for now we have to clear BH_New so that DAX code
3279		 * doesn't attempt to zero blocks again in a racy way.
3280		 */
3281		map.m_flags &= ~EXT4_MAP_NEW;
3282		ext4_update_bh_state(bh_result, map.m_flags);
3283		bh_result->b_size = map.m_len << inode->i_blkbits;
3284		ret = 0;
3285	}
3286	return ret;
3287}
3288#endif
3289
3290static int ext4_end_io_dio(struct kiocb *iocb, loff_t offset,
3291			    ssize_t size, void *private)
3292{
3293        ext4_io_end_t *io_end = private;
3294
3295	/* if not async direct IO just return */
3296	if (!io_end)
3297		return 0;
3298
3299	ext_debug("ext4_end_io_dio(): io_end 0x%p "
3300		  "for inode %lu, iocb 0x%p, offset %llu, size %zd\n",
3301		  io_end, io_end->inode->i_ino, iocb, offset, size);
 
3302
3303	/*
3304	 * Error during AIO DIO. We cannot convert unwritten extents as the
3305	 * data was not written. Just clear the unwritten flag and drop io_end.
3306	 */
3307	if (size <= 0) {
3308		ext4_clear_io_unwritten_flag(io_end);
3309		size = 0;
3310	}
3311	io_end->offset = offset;
3312	io_end->size = size;
3313	ext4_put_io_end(io_end);
3314
3315	return 0;
3316}
3317
3318/*
3319 * For ext4 extent files, ext4 will do direct-io write to holes,
3320 * preallocated extents, and those write extend the file, no need to
3321 * fall back to buffered IO.
3322 *
3323 * For holes, we fallocate those blocks, mark them as unwritten
3324 * If those blocks were preallocated, we mark sure they are split, but
3325 * still keep the range to write as unwritten.
3326 *
3327 * The unwritten extents will be converted to written when DIO is completed.
3328 * For async direct IO, since the IO may still pending when return, we
3329 * set up an end_io call back function, which will do the conversion
3330 * when async direct IO completed.
3331 *
3332 * If the O_DIRECT write will extend the file then add this inode to the
3333 * orphan list.  So recovery will truncate it back to the original size
3334 * if the machine crashes during the write.
3335 *
3336 */
3337static ssize_t ext4_ext_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
3338				  loff_t offset)
 
3339{
3340	struct file *file = iocb->ki_filp;
3341	struct inode *inode = file->f_mapping->host;
3342	ssize_t ret;
3343	size_t count = iov_iter_count(iter);
3344	int overwrite = 0;
3345	get_block_t *get_block_func = NULL;
3346	int dio_flags = 0;
3347	loff_t final_size = offset + count;
 
3348
3349	/* Use the old path for reads and writes beyond i_size. */
3350	if (iov_iter_rw(iter) != WRITE || final_size > inode->i_size)
3351		return ext4_ind_direct_IO(iocb, iter, offset);
3352
3353	BUG_ON(iocb->private == NULL);
3354
3355	/*
3356	 * Make all waiters for direct IO properly wait also for extent
3357	 * conversion. This also disallows race between truncate() and
3358	 * overwrite DIO as i_dio_count needs to be incremented under i_mutex.
3359	 */
3360	if (iov_iter_rw(iter) == WRITE)
3361		inode_dio_begin(inode);
3362
3363	/* If we do a overwrite dio, i_mutex locking can be released */
3364	overwrite = *((int *)iocb->private);
3365
3366	if (overwrite)
3367		inode_unlock(inode);
 
 
3368
3369	/*
3370	 * We could direct write to holes and fallocate.
3371	 *
3372	 * Allocated blocks to fill the hole are marked as unwritten to prevent
3373	 * parallel buffered read to expose the stale data before DIO complete
3374	 * the data IO.
3375	 *
3376	 * As to previously fallocated extents, ext4 get_block will just simply
3377	 * mark the buffer mapped but still keep the extents unwritten.
 
3378	 *
3379	 * For non AIO case, we will convert those unwritten extents to written
3380	 * after return back from blockdev_direct_IO. That way we save us from
3381	 * allocating io_end structure and also the overhead of offloading
3382	 * the extent convertion to a workqueue.
3383	 *
3384	 * For async DIO, the conversion needs to be deferred when the
3385	 * IO is completed. The ext4 end_io callback function will be
3386	 * called to take care of the conversion work.  Here for async
3387	 * case, we allocate an io_end structure to hook to the iocb.
3388	 */
3389	iocb->private = NULL;
3390	if (overwrite)
3391		get_block_func = ext4_dio_get_block_overwrite;
3392	else if (is_sync_kiocb(iocb)) {
3393		get_block_func = ext4_dio_get_block_unwritten_sync;
3394		dio_flags = DIO_LOCKING;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3395	} else {
3396		get_block_func = ext4_dio_get_block_unwritten_async;
3397		dio_flags = DIO_LOCKING;
3398	}
3399#ifdef CONFIG_EXT4_FS_ENCRYPTION
3400	BUG_ON(ext4_encrypted_inode(inode) && S_ISREG(inode->i_mode));
3401#endif
3402	if (IS_DAX(inode))
3403		ret = dax_do_io(iocb, inode, iter, offset, get_block_func,
3404				ext4_end_io_dio, dio_flags);
3405	else
3406		ret = __blockdev_direct_IO(iocb, inode,
3407					   inode->i_sb->s_bdev, iter, offset,
3408					   get_block_func,
3409					   ext4_end_io_dio, NULL, dio_flags);
3410
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3411	if (ret > 0 && !overwrite && ext4_test_inode_state(inode,
3412						EXT4_STATE_DIO_UNWRITTEN)) {
3413		int err;
3414		/*
3415		 * for non AIO case, since the IO is already
3416		 * completed, we could do the conversion right here
3417		 */
3418		err = ext4_convert_unwritten_extents(NULL, inode,
3419						     offset, ret);
3420		if (err < 0)
3421			ret = err;
3422		ext4_clear_inode_state(inode, EXT4_STATE_DIO_UNWRITTEN);
3423	}
3424
3425	if (iov_iter_rw(iter) == WRITE)
3426		inode_dio_end(inode);
 
3427	/* take i_mutex locking again if we do a ovewrite dio */
3428	if (overwrite)
3429		inode_lock(inode);
 
 
3430
3431	return ret;
3432}
3433
3434static ssize_t ext4_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
3435			      loff_t offset)
 
3436{
3437	struct file *file = iocb->ki_filp;
3438	struct inode *inode = file->f_mapping->host;
3439	size_t count = iov_iter_count(iter);
3440	ssize_t ret;
3441
3442#ifdef CONFIG_EXT4_FS_ENCRYPTION
3443	if (ext4_encrypted_inode(inode) && S_ISREG(inode->i_mode))
3444		return 0;
3445#endif
3446
3447	/*
3448	 * If we are doing data journalling we don't support O_DIRECT
3449	 */
3450	if (ext4_should_journal_data(inode))
3451		return 0;
3452
3453	/* Let buffer I/O handle the inline data case. */
3454	if (ext4_has_inline_data(inode))
3455		return 0;
3456
3457	trace_ext4_direct_IO_enter(inode, offset, count, iov_iter_rw(iter));
3458	if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
3459		ret = ext4_ext_direct_IO(iocb, iter, offset);
3460	else
3461		ret = ext4_ind_direct_IO(iocb, iter, offset);
3462	trace_ext4_direct_IO_exit(inode, offset, count, iov_iter_rw(iter), ret);
 
3463	return ret;
3464}
3465
3466/*
3467 * Pages can be marked dirty completely asynchronously from ext4's journalling
3468 * activity.  By filemap_sync_pte(), try_to_unmap_one(), etc.  We cannot do
3469 * much here because ->set_page_dirty is called under VFS locks.  The page is
3470 * not necessarily locked.
3471 *
3472 * We cannot just dirty the page and leave attached buffers clean, because the
3473 * buffers' dirty state is "definitive".  We cannot just set the buffers dirty
3474 * or jbddirty because all the journalling code will explode.
3475 *
3476 * So what we do is to mark the page "pending dirty" and next time writepage
3477 * is called, propagate that into the buffers appropriately.
3478 */
3479static int ext4_journalled_set_page_dirty(struct page *page)
3480{
3481	SetPageChecked(page);
3482	return __set_page_dirty_nobuffers(page);
3483}
3484
3485static const struct address_space_operations ext4_aops = {
3486	.readpage		= ext4_readpage,
3487	.readpages		= ext4_readpages,
3488	.writepage		= ext4_writepage,
3489	.writepages		= ext4_writepages,
3490	.write_begin		= ext4_write_begin,
3491	.write_end		= ext4_write_end,
3492	.bmap			= ext4_bmap,
3493	.invalidatepage		= ext4_invalidatepage,
3494	.releasepage		= ext4_releasepage,
3495	.direct_IO		= ext4_direct_IO,
3496	.migratepage		= buffer_migrate_page,
3497	.is_partially_uptodate  = block_is_partially_uptodate,
3498	.error_remove_page	= generic_error_remove_page,
3499};
3500
3501static const struct address_space_operations ext4_journalled_aops = {
3502	.readpage		= ext4_readpage,
3503	.readpages		= ext4_readpages,
3504	.writepage		= ext4_writepage,
3505	.writepages		= ext4_writepages,
3506	.write_begin		= ext4_write_begin,
3507	.write_end		= ext4_journalled_write_end,
3508	.set_page_dirty		= ext4_journalled_set_page_dirty,
3509	.bmap			= ext4_bmap,
3510	.invalidatepage		= ext4_journalled_invalidatepage,
3511	.releasepage		= ext4_releasepage,
3512	.direct_IO		= ext4_direct_IO,
3513	.is_partially_uptodate  = block_is_partially_uptodate,
3514	.error_remove_page	= generic_error_remove_page,
3515};
3516
3517static const struct address_space_operations ext4_da_aops = {
3518	.readpage		= ext4_readpage,
3519	.readpages		= ext4_readpages,
3520	.writepage		= ext4_writepage,
3521	.writepages		= ext4_writepages,
3522	.write_begin		= ext4_da_write_begin,
3523	.write_end		= ext4_da_write_end,
3524	.bmap			= ext4_bmap,
3525	.invalidatepage		= ext4_da_invalidatepage,
3526	.releasepage		= ext4_releasepage,
3527	.direct_IO		= ext4_direct_IO,
3528	.migratepage		= buffer_migrate_page,
3529	.is_partially_uptodate  = block_is_partially_uptodate,
3530	.error_remove_page	= generic_error_remove_page,
3531};
3532
3533void ext4_set_aops(struct inode *inode)
3534{
3535	switch (ext4_inode_journal_mode(inode)) {
3536	case EXT4_INODE_ORDERED_DATA_MODE:
3537		ext4_set_inode_state(inode, EXT4_STATE_ORDERED_MODE);
3538		break;
3539	case EXT4_INODE_WRITEBACK_DATA_MODE:
3540		ext4_clear_inode_state(inode, EXT4_STATE_ORDERED_MODE);
3541		break;
3542	case EXT4_INODE_JOURNAL_DATA_MODE:
3543		inode->i_mapping->a_ops = &ext4_journalled_aops;
3544		return;
3545	default:
3546		BUG();
3547	}
3548	if (test_opt(inode->i_sb, DELALLOC))
3549		inode->i_mapping->a_ops = &ext4_da_aops;
3550	else
3551		inode->i_mapping->a_ops = &ext4_aops;
3552}
3553
3554static int __ext4_block_zero_page_range(handle_t *handle,
 
 
 
 
 
 
 
3555		struct address_space *mapping, loff_t from, loff_t length)
3556{
3557	ext4_fsblk_t index = from >> PAGE_SHIFT;
3558	unsigned offset = from & (PAGE_SIZE-1);
3559	unsigned blocksize, pos;
3560	ext4_lblk_t iblock;
3561	struct inode *inode = mapping->host;
3562	struct buffer_head *bh;
3563	struct page *page;
3564	int err = 0;
3565
3566	page = find_or_create_page(mapping, from >> PAGE_SHIFT,
3567				   mapping_gfp_constraint(mapping, ~__GFP_FS));
3568	if (!page)
3569		return -ENOMEM;
3570
3571	blocksize = inode->i_sb->s_blocksize;
 
3572
3573	iblock = index << (PAGE_SHIFT - inode->i_sb->s_blocksize_bits);
 
 
 
 
 
 
 
3574
3575	if (!page_has_buffers(page))
3576		create_empty_buffers(page, blocksize, 0);
3577
3578	/* Find the buffer that contains "offset" */
3579	bh = page_buffers(page);
3580	pos = blocksize;
3581	while (offset >= pos) {
3582		bh = bh->b_this_page;
3583		iblock++;
3584		pos += blocksize;
3585	}
3586	if (buffer_freed(bh)) {
3587		BUFFER_TRACE(bh, "freed: skip");
3588		goto unlock;
3589	}
3590	if (!buffer_mapped(bh)) {
3591		BUFFER_TRACE(bh, "unmapped");
3592		ext4_get_block(inode, iblock, bh, 0);
3593		/* unmapped? It's a hole - nothing to do */
3594		if (!buffer_mapped(bh)) {
3595			BUFFER_TRACE(bh, "still unmapped");
3596			goto unlock;
3597		}
3598	}
3599
3600	/* Ok, it's mapped. Make sure it's up-to-date */
3601	if (PageUptodate(page))
3602		set_buffer_uptodate(bh);
3603
3604	if (!buffer_uptodate(bh)) {
3605		err = -EIO;
3606		ll_rw_block(READ, 1, &bh);
3607		wait_on_buffer(bh);
3608		/* Uhhuh. Read error. Complain and punt. */
3609		if (!buffer_uptodate(bh))
3610			goto unlock;
3611		if (S_ISREG(inode->i_mode) &&
3612		    ext4_encrypted_inode(inode)) {
3613			/* We expect the key to be set. */
3614			BUG_ON(!ext4_has_encryption_key(inode));
3615			BUG_ON(blocksize != PAGE_SIZE);
3616			WARN_ON_ONCE(ext4_decrypt(page));
3617		}
3618	}
3619	if (ext4_should_journal_data(inode)) {
3620		BUFFER_TRACE(bh, "get write access");
3621		err = ext4_journal_get_write_access(handle, bh);
3622		if (err)
3623			goto unlock;
3624	}
3625	zero_user(page, offset, length);
3626	BUFFER_TRACE(bh, "zeroed end of block");
3627
3628	if (ext4_should_journal_data(inode)) {
3629		err = ext4_handle_dirty_metadata(handle, inode, bh);
3630	} else {
3631		err = 0;
3632		mark_buffer_dirty(bh);
3633		if (ext4_test_inode_state(inode, EXT4_STATE_ORDERED_MODE))
3634			err = ext4_jbd2_file_inode(handle, inode);
3635	}
3636
3637unlock:
3638	unlock_page(page);
3639	put_page(page);
3640	return err;
3641}
3642
3643/*
3644 * ext4_block_zero_page_range() zeros out a mapping of length 'length'
3645 * starting from file offset 'from'.  The range to be zero'd must
3646 * be contained with in one block.  If the specified range exceeds
3647 * the end of the block it will be shortened to end of the block
3648 * that cooresponds to 'from'
3649 */
3650static int ext4_block_zero_page_range(handle_t *handle,
3651		struct address_space *mapping, loff_t from, loff_t length)
3652{
3653	struct inode *inode = mapping->host;
3654	unsigned offset = from & (PAGE_SIZE-1);
3655	unsigned blocksize = inode->i_sb->s_blocksize;
3656	unsigned max = blocksize - (offset & (blocksize - 1));
3657
3658	/*
3659	 * correct length if it does not fall between
3660	 * 'from' and the end of the block
3661	 */
3662	if (length > max || length < 0)
3663		length = max;
3664
3665	if (IS_DAX(inode))
3666		return dax_zero_page_range(inode, from, length, ext4_get_block);
3667	return __ext4_block_zero_page_range(handle, mapping, from, length);
3668}
3669
3670/*
3671 * ext4_block_truncate_page() zeroes out a mapping from file offset `from'
3672 * up to the end of the block which corresponds to `from'.
3673 * This required during truncate. We need to physically zero the tail end
3674 * of that block so it doesn't yield old data if the file is later grown.
3675 */
3676static int ext4_block_truncate_page(handle_t *handle,
3677		struct address_space *mapping, loff_t from)
3678{
3679	unsigned offset = from & (PAGE_SIZE-1);
3680	unsigned length;
3681	unsigned blocksize;
3682	struct inode *inode = mapping->host;
3683
3684	blocksize = inode->i_sb->s_blocksize;
3685	length = blocksize - (offset & (blocksize - 1));
3686
3687	return ext4_block_zero_page_range(handle, mapping, from, length);
3688}
3689
3690int ext4_zero_partial_blocks(handle_t *handle, struct inode *inode,
3691			     loff_t lstart, loff_t length)
3692{
3693	struct super_block *sb = inode->i_sb;
3694	struct address_space *mapping = inode->i_mapping;
3695	unsigned partial_start, partial_end;
3696	ext4_fsblk_t start, end;
3697	loff_t byte_end = (lstart + length - 1);
3698	int err = 0;
3699
3700	partial_start = lstart & (sb->s_blocksize - 1);
3701	partial_end = byte_end & (sb->s_blocksize - 1);
3702
3703	start = lstart >> sb->s_blocksize_bits;
3704	end = byte_end >> sb->s_blocksize_bits;
3705
3706	/* Handle partial zero within the single block */
3707	if (start == end &&
3708	    (partial_start || (partial_end != sb->s_blocksize - 1))) {
3709		err = ext4_block_zero_page_range(handle, mapping,
3710						 lstart, length);
3711		return err;
3712	}
3713	/* Handle partial zero out on the start of the range */
3714	if (partial_start) {
3715		err = ext4_block_zero_page_range(handle, mapping,
3716						 lstart, sb->s_blocksize);
3717		if (err)
3718			return err;
3719	}
3720	/* Handle partial zero out on the end of the range */
3721	if (partial_end != sb->s_blocksize - 1)
3722		err = ext4_block_zero_page_range(handle, mapping,
3723						 byte_end - partial_end,
3724						 partial_end + 1);
3725	return err;
3726}
3727
3728int ext4_can_truncate(struct inode *inode)
3729{
3730	if (S_ISREG(inode->i_mode))
3731		return 1;
3732	if (S_ISDIR(inode->i_mode))
3733		return 1;
3734	if (S_ISLNK(inode->i_mode))
3735		return !ext4_inode_is_fast_symlink(inode);
3736	return 0;
3737}
3738
3739/*
3740 * We have to make sure i_disksize gets properly updated before we truncate
3741 * page cache due to hole punching or zero range. Otherwise i_disksize update
3742 * can get lost as it may have been postponed to submission of writeback but
3743 * that will never happen after we truncate page cache.
3744 */
3745int ext4_update_disksize_before_punch(struct inode *inode, loff_t offset,
3746				      loff_t len)
3747{
3748	handle_t *handle;
3749	loff_t size = i_size_read(inode);
3750
3751	WARN_ON(!inode_is_locked(inode));
3752	if (offset > size || offset + len < size)
3753		return 0;
3754
3755	if (EXT4_I(inode)->i_disksize >= size)
3756		return 0;
3757
3758	handle = ext4_journal_start(inode, EXT4_HT_MISC, 1);
3759	if (IS_ERR(handle))
3760		return PTR_ERR(handle);
3761	ext4_update_i_disksize(inode, size);
3762	ext4_mark_inode_dirty(handle, inode);
3763	ext4_journal_stop(handle);
3764
3765	return 0;
3766}
3767
3768/*
3769 * ext4_punch_hole: punches a hole in a file by releaseing the blocks
3770 * associated with the given offset and length
3771 *
3772 * @inode:  File inode
3773 * @offset: The offset where the hole will begin
3774 * @len:    The length of the hole
3775 *
3776 * Returns: 0 on success or negative on failure
3777 */
3778
3779int ext4_punch_hole(struct inode *inode, loff_t offset, loff_t length)
3780{
3781	struct super_block *sb = inode->i_sb;
3782	ext4_lblk_t first_block, stop_block;
3783	struct address_space *mapping = inode->i_mapping;
3784	loff_t first_block_offset, last_block_offset;
3785	handle_t *handle;
3786	unsigned int credits;
3787	int ret = 0;
3788
3789	if (!S_ISREG(inode->i_mode))
3790		return -EOPNOTSUPP;
3791
3792	trace_ext4_punch_hole(inode, offset, length, 0);
3793
3794	/*
3795	 * Write out all dirty pages to avoid race conditions
3796	 * Then release them.
3797	 */
3798	if (mapping->nrpages && mapping_tagged(mapping, PAGECACHE_TAG_DIRTY)) {
3799		ret = filemap_write_and_wait_range(mapping, offset,
3800						   offset + length - 1);
3801		if (ret)
3802			return ret;
3803	}
3804
3805	inode_lock(inode);
3806
3807	/* No need to punch hole beyond i_size */
3808	if (offset >= inode->i_size)
3809		goto out_mutex;
3810
3811	/*
3812	 * If the hole extends beyond i_size, set the hole
3813	 * to end after the page that contains i_size
3814	 */
3815	if (offset + length > inode->i_size) {
3816		length = inode->i_size +
3817		   PAGE_SIZE - (inode->i_size & (PAGE_SIZE - 1)) -
3818		   offset;
3819	}
3820
3821	if (offset & (sb->s_blocksize - 1) ||
3822	    (offset + length) & (sb->s_blocksize - 1)) {
3823		/*
3824		 * Attach jinode to inode for jbd2 if we do any zeroing of
3825		 * partial block
3826		 */
3827		ret = ext4_inode_attach_jinode(inode);
3828		if (ret < 0)
3829			goto out_mutex;
3830
3831	}
3832
3833	/* Wait all existing dio workers, newcomers will block on i_mutex */
3834	ext4_inode_block_unlocked_dio(inode);
3835	inode_dio_wait(inode);
3836
3837	/*
3838	 * Prevent page faults from reinstantiating pages we have released from
3839	 * page cache.
3840	 */
3841	down_write(&EXT4_I(inode)->i_mmap_sem);
3842	first_block_offset = round_up(offset, sb->s_blocksize);
3843	last_block_offset = round_down((offset + length), sb->s_blocksize) - 1;
3844
3845	/* Now release the pages and zero block aligned part of pages*/
3846	if (last_block_offset > first_block_offset) {
3847		ret = ext4_update_disksize_before_punch(inode, offset, length);
3848		if (ret)
3849			goto out_dio;
3850		truncate_pagecache_range(inode, first_block_offset,
3851					 last_block_offset);
3852	}
 
 
 
3853
3854	if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
3855		credits = ext4_writepage_trans_blocks(inode);
3856	else
3857		credits = ext4_blocks_for_truncate(inode);
3858	handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE, credits);
3859	if (IS_ERR(handle)) {
3860		ret = PTR_ERR(handle);
3861		ext4_std_error(sb, ret);
3862		goto out_dio;
3863	}
3864
3865	ret = ext4_zero_partial_blocks(handle, inode, offset,
3866				       length);
3867	if (ret)
3868		goto out_stop;
3869
3870	first_block = (offset + sb->s_blocksize - 1) >>
3871		EXT4_BLOCK_SIZE_BITS(sb);
3872	stop_block = (offset + length) >> EXT4_BLOCK_SIZE_BITS(sb);
3873
3874	/* If there are no blocks to remove, return now */
3875	if (first_block >= stop_block)
3876		goto out_stop;
3877
3878	down_write(&EXT4_I(inode)->i_data_sem);
3879	ext4_discard_preallocations(inode);
3880
3881	ret = ext4_es_remove_extent(inode, first_block,
3882				    stop_block - first_block);
3883	if (ret) {
3884		up_write(&EXT4_I(inode)->i_data_sem);
3885		goto out_stop;
3886	}
3887
3888	if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
3889		ret = ext4_ext_remove_space(inode, first_block,
3890					    stop_block - 1);
3891	else
3892		ret = ext4_ind_remove_space(handle, inode, first_block,
3893					    stop_block);
3894
3895	up_write(&EXT4_I(inode)->i_data_sem);
3896	if (IS_SYNC(inode))
3897		ext4_handle_sync(handle);
3898
 
 
 
 
 
3899	inode->i_mtime = inode->i_ctime = ext4_current_time(inode);
3900	ext4_mark_inode_dirty(handle, inode);
3901out_stop:
3902	ext4_journal_stop(handle);
3903out_dio:
3904	up_write(&EXT4_I(inode)->i_mmap_sem);
3905	ext4_inode_resume_unlocked_dio(inode);
3906out_mutex:
3907	inode_unlock(inode);
3908	return ret;
3909}
3910
3911int ext4_inode_attach_jinode(struct inode *inode)
3912{
3913	struct ext4_inode_info *ei = EXT4_I(inode);
3914	struct jbd2_inode *jinode;
3915
3916	if (ei->jinode || !EXT4_SB(inode->i_sb)->s_journal)
3917		return 0;
3918
3919	jinode = jbd2_alloc_inode(GFP_KERNEL);
3920	spin_lock(&inode->i_lock);
3921	if (!ei->jinode) {
3922		if (!jinode) {
3923			spin_unlock(&inode->i_lock);
3924			return -ENOMEM;
3925		}
3926		ei->jinode = jinode;
3927		jbd2_journal_init_jbd_inode(ei->jinode, inode);
3928		jinode = NULL;
3929	}
3930	spin_unlock(&inode->i_lock);
3931	if (unlikely(jinode != NULL))
3932		jbd2_free_inode(jinode);
3933	return 0;
3934}
3935
3936/*
3937 * ext4_truncate()
3938 *
3939 * We block out ext4_get_block() block instantiations across the entire
3940 * transaction, and VFS/VM ensures that ext4_truncate() cannot run
3941 * simultaneously on behalf of the same inode.
3942 *
3943 * As we work through the truncate and commit bits of it to the journal there
3944 * is one core, guiding principle: the file's tree must always be consistent on
3945 * disk.  We must be able to restart the truncate after a crash.
3946 *
3947 * The file's tree may be transiently inconsistent in memory (although it
3948 * probably isn't), but whenever we close off and commit a journal transaction,
3949 * the contents of (the filesystem + the journal) must be consistent and
3950 * restartable.  It's pretty simple, really: bottom up, right to left (although
3951 * left-to-right works OK too).
3952 *
3953 * Note that at recovery time, journal replay occurs *before* the restart of
3954 * truncate against the orphan inode list.
3955 *
3956 * The committed inode has the new, desired i_size (which is the same as
3957 * i_disksize in this case).  After a crash, ext4_orphan_cleanup() will see
3958 * that this inode's truncate did not complete and it will again call
3959 * ext4_truncate() to have another go.  So there will be instantiated blocks
3960 * to the right of the truncation point in a crashed ext4 filesystem.  But
3961 * that's fine - as long as they are linked from the inode, the post-crash
3962 * ext4_truncate() run will find them and release them.
3963 */
3964void ext4_truncate(struct inode *inode)
3965{
3966	struct ext4_inode_info *ei = EXT4_I(inode);
3967	unsigned int credits;
3968	handle_t *handle;
3969	struct address_space *mapping = inode->i_mapping;
3970
3971	/*
3972	 * There is a possibility that we're either freeing the inode
3973	 * or it's a completely new inode. In those cases we might not
3974	 * have i_mutex locked because it's not necessary.
3975	 */
3976	if (!(inode->i_state & (I_NEW|I_FREEING)))
3977		WARN_ON(!inode_is_locked(inode));
3978	trace_ext4_truncate_enter(inode);
3979
3980	if (!ext4_can_truncate(inode))
3981		return;
3982
3983	ext4_clear_inode_flag(inode, EXT4_INODE_EOFBLOCKS);
3984
3985	if (inode->i_size == 0 && !test_opt(inode->i_sb, NO_AUTO_DA_ALLOC))
3986		ext4_set_inode_state(inode, EXT4_STATE_DA_ALLOC_CLOSE);
3987
3988	if (ext4_has_inline_data(inode)) {
3989		int has_inline = 1;
3990
3991		ext4_inline_data_truncate(inode, &has_inline);
3992		if (has_inline)
3993			return;
3994	}
3995
3996	/* If we zero-out tail of the page, we have to create jinode for jbd2 */
3997	if (inode->i_size & (inode->i_sb->s_blocksize - 1)) {
3998		if (ext4_inode_attach_jinode(inode) < 0)
3999			return;
4000	}
4001
4002	if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
4003		credits = ext4_writepage_trans_blocks(inode);
4004	else
4005		credits = ext4_blocks_for_truncate(inode);
4006
4007	handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE, credits);
4008	if (IS_ERR(handle)) {
4009		ext4_std_error(inode->i_sb, PTR_ERR(handle));
4010		return;
4011	}
4012
4013	if (inode->i_size & (inode->i_sb->s_blocksize - 1))
4014		ext4_block_truncate_page(handle, mapping, inode->i_size);
4015
4016	/*
4017	 * We add the inode to the orphan list, so that if this
4018	 * truncate spans multiple transactions, and we crash, we will
4019	 * resume the truncate when the filesystem recovers.  It also
4020	 * marks the inode dirty, to catch the new size.
4021	 *
4022	 * Implication: the file must always be in a sane, consistent
4023	 * truncatable state while each transaction commits.
4024	 */
4025	if (ext4_orphan_add(handle, inode))
4026		goto out_stop;
4027
4028	down_write(&EXT4_I(inode)->i_data_sem);
4029
4030	ext4_discard_preallocations(inode);
4031
4032	if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
4033		ext4_ext_truncate(handle, inode);
4034	else
4035		ext4_ind_truncate(handle, inode);
4036
4037	up_write(&ei->i_data_sem);
4038
4039	if (IS_SYNC(inode))
4040		ext4_handle_sync(handle);
4041
4042out_stop:
4043	/*
4044	 * If this was a simple ftruncate() and the file will remain alive,
4045	 * then we need to clear up the orphan record which we created above.
4046	 * However, if this was a real unlink then we were called by
4047	 * ext4_evict_inode(), and we allow that function to clean up the
4048	 * orphan info for us.
4049	 */
4050	if (inode->i_nlink)
4051		ext4_orphan_del(handle, inode);
4052
4053	inode->i_mtime = inode->i_ctime = ext4_current_time(inode);
4054	ext4_mark_inode_dirty(handle, inode);
4055	ext4_journal_stop(handle);
4056
4057	trace_ext4_truncate_exit(inode);
4058}
4059
4060/*
4061 * ext4_get_inode_loc returns with an extra refcount against the inode's
4062 * underlying buffer_head on success. If 'in_mem' is true, we have all
4063 * data in memory that is needed to recreate the on-disk version of this
4064 * inode.
4065 */
4066static int __ext4_get_inode_loc(struct inode *inode,
4067				struct ext4_iloc *iloc, int in_mem)
4068{
4069	struct ext4_group_desc	*gdp;
4070	struct buffer_head	*bh;
4071	struct super_block	*sb = inode->i_sb;
4072	ext4_fsblk_t		block;
4073	int			inodes_per_block, inode_offset;
4074
4075	iloc->bh = NULL;
4076	if (!ext4_valid_inum(sb, inode->i_ino))
4077		return -EFSCORRUPTED;
4078
4079	iloc->block_group = (inode->i_ino - 1) / EXT4_INODES_PER_GROUP(sb);
4080	gdp = ext4_get_group_desc(sb, iloc->block_group, NULL);
4081	if (!gdp)
4082		return -EIO;
4083
4084	/*
4085	 * Figure out the offset within the block group inode table
4086	 */
4087	inodes_per_block = EXT4_SB(sb)->s_inodes_per_block;
4088	inode_offset = ((inode->i_ino - 1) %
4089			EXT4_INODES_PER_GROUP(sb));
4090	block = ext4_inode_table(sb, gdp) + (inode_offset / inodes_per_block);
4091	iloc->offset = (inode_offset % inodes_per_block) * EXT4_INODE_SIZE(sb);
4092
4093	bh = sb_getblk(sb, block);
4094	if (unlikely(!bh))
4095		return -ENOMEM;
4096	if (!buffer_uptodate(bh)) {
4097		lock_buffer(bh);
4098
4099		/*
4100		 * If the buffer has the write error flag, we have failed
4101		 * to write out another inode in the same block.  In this
4102		 * case, we don't have to read the block because we may
4103		 * read the old inode data successfully.
4104		 */
4105		if (buffer_write_io_error(bh) && !buffer_uptodate(bh))
4106			set_buffer_uptodate(bh);
4107
4108		if (buffer_uptodate(bh)) {
4109			/* someone brought it uptodate while we waited */
4110			unlock_buffer(bh);
4111			goto has_buffer;
4112		}
4113
4114		/*
4115		 * If we have all information of the inode in memory and this
4116		 * is the only valid inode in the block, we need not read the
4117		 * block.
4118		 */
4119		if (in_mem) {
4120			struct buffer_head *bitmap_bh;
4121			int i, start;
4122
4123			start = inode_offset & ~(inodes_per_block - 1);
4124
4125			/* Is the inode bitmap in cache? */
4126			bitmap_bh = sb_getblk(sb, ext4_inode_bitmap(sb, gdp));
4127			if (unlikely(!bitmap_bh))
4128				goto make_io;
4129
4130			/*
4131			 * If the inode bitmap isn't in cache then the
4132			 * optimisation may end up performing two reads instead
4133			 * of one, so skip it.
4134			 */
4135			if (!buffer_uptodate(bitmap_bh)) {
4136				brelse(bitmap_bh);
4137				goto make_io;
4138			}
4139			for (i = start; i < start + inodes_per_block; i++) {
4140				if (i == inode_offset)
4141					continue;
4142				if (ext4_test_bit(i, bitmap_bh->b_data))
4143					break;
4144			}
4145			brelse(bitmap_bh);
4146			if (i == start + inodes_per_block) {
4147				/* all other inodes are free, so skip I/O */
4148				memset(bh->b_data, 0, bh->b_size);
4149				set_buffer_uptodate(bh);
4150				unlock_buffer(bh);
4151				goto has_buffer;
4152			}
4153		}
4154
4155make_io:
4156		/*
4157		 * If we need to do any I/O, try to pre-readahead extra
4158		 * blocks from the inode table.
4159		 */
4160		if (EXT4_SB(sb)->s_inode_readahead_blks) {
4161			ext4_fsblk_t b, end, table;
4162			unsigned num;
4163			__u32 ra_blks = EXT4_SB(sb)->s_inode_readahead_blks;
4164
4165			table = ext4_inode_table(sb, gdp);
4166			/* s_inode_readahead_blks is always a power of 2 */
4167			b = block & ~((ext4_fsblk_t) ra_blks - 1);
4168			if (table > b)
4169				b = table;
4170			end = b + ra_blks;
4171			num = EXT4_INODES_PER_GROUP(sb);
4172			if (ext4_has_group_desc_csum(sb))
4173				num -= ext4_itable_unused_count(sb, gdp);
4174			table += num / inodes_per_block;
4175			if (end > table)
4176				end = table;
4177			while (b <= end)
4178				sb_breadahead(sb, b++);
4179		}
4180
4181		/*
4182		 * There are other valid inodes in the buffer, this inode
4183		 * has in-inode xattrs, or we don't have this inode in memory.
4184		 * Read the block from disk.
4185		 */
4186		trace_ext4_load_inode(inode);
4187		get_bh(bh);
4188		bh->b_end_io = end_buffer_read_sync;
4189		submit_bh(READ | REQ_META | REQ_PRIO, bh);
4190		wait_on_buffer(bh);
4191		if (!buffer_uptodate(bh)) {
4192			EXT4_ERROR_INODE_BLOCK(inode, block,
4193					       "unable to read itable block");
4194			brelse(bh);
4195			return -EIO;
4196		}
4197	}
4198has_buffer:
4199	iloc->bh = bh;
4200	return 0;
4201}
4202
4203int ext4_get_inode_loc(struct inode *inode, struct ext4_iloc *iloc)
4204{
4205	/* We have all inode data except xattrs in memory here. */
4206	return __ext4_get_inode_loc(inode, iloc,
4207		!ext4_test_inode_state(inode, EXT4_STATE_XATTR));
4208}
4209
4210void ext4_set_inode_flags(struct inode *inode)
4211{
4212	unsigned int flags = EXT4_I(inode)->i_flags;
4213	unsigned int new_fl = 0;
4214
4215	if (flags & EXT4_SYNC_FL)
4216		new_fl |= S_SYNC;
4217	if (flags & EXT4_APPEND_FL)
4218		new_fl |= S_APPEND;
4219	if (flags & EXT4_IMMUTABLE_FL)
4220		new_fl |= S_IMMUTABLE;
4221	if (flags & EXT4_NOATIME_FL)
4222		new_fl |= S_NOATIME;
4223	if (flags & EXT4_DIRSYNC_FL)
4224		new_fl |= S_DIRSYNC;
4225	if (test_opt(inode->i_sb, DAX) && S_ISREG(inode->i_mode))
4226		new_fl |= S_DAX;
4227	inode_set_flags(inode, new_fl,
4228			S_SYNC|S_APPEND|S_IMMUTABLE|S_NOATIME|S_DIRSYNC|S_DAX);
4229}
4230
4231/* Propagate flags from i_flags to EXT4_I(inode)->i_flags */
4232void ext4_get_inode_flags(struct ext4_inode_info *ei)
4233{
4234	unsigned int vfs_fl;
4235	unsigned long old_fl, new_fl;
4236
4237	do {
4238		vfs_fl = ei->vfs_inode.i_flags;
4239		old_fl = ei->i_flags;
4240		new_fl = old_fl & ~(EXT4_SYNC_FL|EXT4_APPEND_FL|
4241				EXT4_IMMUTABLE_FL|EXT4_NOATIME_FL|
4242				EXT4_DIRSYNC_FL);
4243		if (vfs_fl & S_SYNC)
4244			new_fl |= EXT4_SYNC_FL;
4245		if (vfs_fl & S_APPEND)
4246			new_fl |= EXT4_APPEND_FL;
4247		if (vfs_fl & S_IMMUTABLE)
4248			new_fl |= EXT4_IMMUTABLE_FL;
4249		if (vfs_fl & S_NOATIME)
4250			new_fl |= EXT4_NOATIME_FL;
4251		if (vfs_fl & S_DIRSYNC)
4252			new_fl |= EXT4_DIRSYNC_FL;
4253	} while (cmpxchg(&ei->i_flags, old_fl, new_fl) != old_fl);
4254}
4255
4256static blkcnt_t ext4_inode_blocks(struct ext4_inode *raw_inode,
4257				  struct ext4_inode_info *ei)
4258{
4259	blkcnt_t i_blocks ;
4260	struct inode *inode = &(ei->vfs_inode);
4261	struct super_block *sb = inode->i_sb;
4262
4263	if (ext4_has_feature_huge_file(sb)) {
 
4264		/* we are using combined 48 bit field */
4265		i_blocks = ((u64)le16_to_cpu(raw_inode->i_blocks_high)) << 32 |
4266					le32_to_cpu(raw_inode->i_blocks_lo);
4267		if (ext4_test_inode_flag(inode, EXT4_INODE_HUGE_FILE)) {
4268			/* i_blocks represent file system block size */
4269			return i_blocks  << (inode->i_blkbits - 9);
4270		} else {
4271			return i_blocks;
4272		}
4273	} else {
4274		return le32_to_cpu(raw_inode->i_blocks_lo);
4275	}
4276}
4277
4278static inline void ext4_iget_extra_inode(struct inode *inode,
4279					 struct ext4_inode *raw_inode,
4280					 struct ext4_inode_info *ei)
4281{
4282	__le32 *magic = (void *)raw_inode +
4283			EXT4_GOOD_OLD_INODE_SIZE + ei->i_extra_isize;
4284	if (*magic == cpu_to_le32(EXT4_XATTR_MAGIC)) {
4285		ext4_set_inode_state(inode, EXT4_STATE_XATTR);
4286		ext4_find_inline_data_nolock(inode);
4287	} else
4288		EXT4_I(inode)->i_inline_off = 0;
4289}
4290
4291int ext4_get_projid(struct inode *inode, kprojid_t *projid)
4292{
4293	if (!EXT4_HAS_RO_COMPAT_FEATURE(inode->i_sb, EXT4_FEATURE_RO_COMPAT_PROJECT))
4294		return -EOPNOTSUPP;
4295	*projid = EXT4_I(inode)->i_projid;
4296	return 0;
4297}
4298
4299struct inode *ext4_iget(struct super_block *sb, unsigned long ino)
4300{
4301	struct ext4_iloc iloc;
4302	struct ext4_inode *raw_inode;
4303	struct ext4_inode_info *ei;
4304	struct inode *inode;
4305	journal_t *journal = EXT4_SB(sb)->s_journal;
4306	long ret;
4307	int block;
4308	uid_t i_uid;
4309	gid_t i_gid;
4310	projid_t i_projid;
4311
4312	inode = iget_locked(sb, ino);
4313	if (!inode)
4314		return ERR_PTR(-ENOMEM);
4315	if (!(inode->i_state & I_NEW))
4316		return inode;
4317
4318	ei = EXT4_I(inode);
4319	iloc.bh = NULL;
4320
4321	ret = __ext4_get_inode_loc(inode, &iloc, 0);
4322	if (ret < 0)
4323		goto bad_inode;
4324	raw_inode = ext4_raw_inode(&iloc);
4325
4326	if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE) {
4327		ei->i_extra_isize = le16_to_cpu(raw_inode->i_extra_isize);
4328		if (EXT4_GOOD_OLD_INODE_SIZE + ei->i_extra_isize >
4329		    EXT4_INODE_SIZE(inode->i_sb)) {
4330			EXT4_ERROR_INODE(inode, "bad extra_isize (%u != %u)",
4331				EXT4_GOOD_OLD_INODE_SIZE + ei->i_extra_isize,
4332				EXT4_INODE_SIZE(inode->i_sb));
4333			ret = -EFSCORRUPTED;
4334			goto bad_inode;
4335		}
4336	} else
4337		ei->i_extra_isize = 0;
4338
4339	/* Precompute checksum seed for inode metadata */
4340	if (ext4_has_metadata_csum(sb)) {
 
4341		struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
4342		__u32 csum;
4343		__le32 inum = cpu_to_le32(inode->i_ino);
4344		__le32 gen = raw_inode->i_generation;
4345		csum = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)&inum,
4346				   sizeof(inum));
4347		ei->i_csum_seed = ext4_chksum(sbi, csum, (__u8 *)&gen,
4348					      sizeof(gen));
4349	}
4350
4351	if (!ext4_inode_csum_verify(inode, raw_inode, ei)) {
4352		EXT4_ERROR_INODE(inode, "checksum invalid");
4353		ret = -EFSBADCRC;
4354		goto bad_inode;
4355	}
4356
4357	inode->i_mode = le16_to_cpu(raw_inode->i_mode);
4358	i_uid = (uid_t)le16_to_cpu(raw_inode->i_uid_low);
4359	i_gid = (gid_t)le16_to_cpu(raw_inode->i_gid_low);
4360	if (EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_PROJECT) &&
4361	    EXT4_INODE_SIZE(sb) > EXT4_GOOD_OLD_INODE_SIZE &&
4362	    EXT4_FITS_IN_INODE(raw_inode, ei, i_projid))
4363		i_projid = (projid_t)le32_to_cpu(raw_inode->i_projid);
4364	else
4365		i_projid = EXT4_DEF_PROJID;
4366
4367	if (!(test_opt(inode->i_sb, NO_UID32))) {
4368		i_uid |= le16_to_cpu(raw_inode->i_uid_high) << 16;
4369		i_gid |= le16_to_cpu(raw_inode->i_gid_high) << 16;
4370	}
4371	i_uid_write(inode, i_uid);
4372	i_gid_write(inode, i_gid);
4373	ei->i_projid = make_kprojid(&init_user_ns, i_projid);
4374	set_nlink(inode, le16_to_cpu(raw_inode->i_links_count));
4375
4376	ext4_clear_state_flags(ei);	/* Only relevant on 32-bit archs */
4377	ei->i_inline_off = 0;
4378	ei->i_dir_start_lookup = 0;
4379	ei->i_dtime = le32_to_cpu(raw_inode->i_dtime);
4380	/* We now have enough fields to check if the inode was active or not.
4381	 * This is needed because nfsd might try to access dead inodes
4382	 * the test is that same one that e2fsck uses
4383	 * NeilBrown 1999oct15
4384	 */
4385	if (inode->i_nlink == 0) {
4386		if ((inode->i_mode == 0 ||
4387		     !(EXT4_SB(inode->i_sb)->s_mount_state & EXT4_ORPHAN_FS)) &&
4388		    ino != EXT4_BOOT_LOADER_INO) {
4389			/* this inode is deleted */
4390			ret = -ESTALE;
4391			goto bad_inode;
4392		}
4393		/* The only unlinked inodes we let through here have
4394		 * valid i_mode and are being read by the orphan
4395		 * recovery code: that's fine, we're about to complete
4396		 * the process of deleting those.
4397		 * OR it is the EXT4_BOOT_LOADER_INO which is
4398		 * not initialized on a new filesystem. */
4399	}
4400	ei->i_flags = le32_to_cpu(raw_inode->i_flags);
4401	inode->i_blocks = ext4_inode_blocks(raw_inode, ei);
4402	ei->i_file_acl = le32_to_cpu(raw_inode->i_file_acl_lo);
4403	if (ext4_has_feature_64bit(sb))
4404		ei->i_file_acl |=
4405			((__u64)le16_to_cpu(raw_inode->i_file_acl_high)) << 32;
4406	inode->i_size = ext4_isize(raw_inode);
4407	ei->i_disksize = inode->i_size;
4408#ifdef CONFIG_QUOTA
4409	ei->i_reserved_quota = 0;
4410#endif
4411	inode->i_generation = le32_to_cpu(raw_inode->i_generation);
4412	ei->i_block_group = iloc.block_group;
4413	ei->i_last_alloc_group = ~0;
4414	/*
4415	 * NOTE! The in-memory inode i_data array is in little-endian order
4416	 * even on big-endian machines: we do NOT byteswap the block numbers!
4417	 */
4418	for (block = 0; block < EXT4_N_BLOCKS; block++)
4419		ei->i_data[block] = raw_inode->i_block[block];
4420	INIT_LIST_HEAD(&ei->i_orphan);
4421
4422	/*
4423	 * Set transaction id's of transactions that have to be committed
4424	 * to finish f[data]sync. We set them to currently running transaction
4425	 * as we cannot be sure that the inode or some of its metadata isn't
4426	 * part of the transaction - the inode could have been reclaimed and
4427	 * now it is reread from disk.
4428	 */
4429	if (journal) {
4430		transaction_t *transaction;
4431		tid_t tid;
4432
4433		read_lock(&journal->j_state_lock);
4434		if (journal->j_running_transaction)
4435			transaction = journal->j_running_transaction;
4436		else
4437			transaction = journal->j_committing_transaction;
4438		if (transaction)
4439			tid = transaction->t_tid;
4440		else
4441			tid = journal->j_commit_sequence;
4442		read_unlock(&journal->j_state_lock);
4443		ei->i_sync_tid = tid;
4444		ei->i_datasync_tid = tid;
4445	}
4446
4447	if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE) {
4448		if (ei->i_extra_isize == 0) {
4449			/* The extra space is currently unused. Use it. */
4450			ei->i_extra_isize = sizeof(struct ext4_inode) -
4451					    EXT4_GOOD_OLD_INODE_SIZE;
4452		} else {
4453			ext4_iget_extra_inode(inode, raw_inode, ei);
4454		}
4455	}
4456
4457	EXT4_INODE_GET_XTIME(i_ctime, inode, raw_inode);
4458	EXT4_INODE_GET_XTIME(i_mtime, inode, raw_inode);
4459	EXT4_INODE_GET_XTIME(i_atime, inode, raw_inode);
4460	EXT4_EINODE_GET_XTIME(i_crtime, ei, raw_inode);
4461
4462	if (likely(!test_opt2(inode->i_sb, HURD_COMPAT))) {
4463		inode->i_version = le32_to_cpu(raw_inode->i_disk_version);
4464		if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE) {
4465			if (EXT4_FITS_IN_INODE(raw_inode, ei, i_version_hi))
4466				inode->i_version |=
4467		    (__u64)(le32_to_cpu(raw_inode->i_version_hi)) << 32;
4468		}
4469	}
4470
4471	ret = 0;
4472	if (ei->i_file_acl &&
4473	    !ext4_data_block_valid(EXT4_SB(sb), ei->i_file_acl, 1)) {
4474		EXT4_ERROR_INODE(inode, "bad extended attribute block %llu",
4475				 ei->i_file_acl);
4476		ret = -EFSCORRUPTED;
4477		goto bad_inode;
4478	} else if (!ext4_has_inline_data(inode)) {
4479		if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) {
4480			if ((S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
4481			    (S_ISLNK(inode->i_mode) &&
4482			     !ext4_inode_is_fast_symlink(inode))))
4483				/* Validate extent which is part of inode */
4484				ret = ext4_ext_check_inode(inode);
4485		} else if (S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
4486			   (S_ISLNK(inode->i_mode) &&
4487			    !ext4_inode_is_fast_symlink(inode))) {
4488			/* Validate block references which are part of inode */
4489			ret = ext4_ind_check_inode(inode);
4490		}
4491	}
4492	if (ret)
4493		goto bad_inode;
4494
4495	if (S_ISREG(inode->i_mode)) {
4496		inode->i_op = &ext4_file_inode_operations;
4497		inode->i_fop = &ext4_file_operations;
4498		ext4_set_aops(inode);
4499	} else if (S_ISDIR(inode->i_mode)) {
4500		inode->i_op = &ext4_dir_inode_operations;
4501		inode->i_fop = &ext4_dir_operations;
4502	} else if (S_ISLNK(inode->i_mode)) {
4503		if (ext4_encrypted_inode(inode)) {
4504			inode->i_op = &ext4_encrypted_symlink_inode_operations;
4505			ext4_set_aops(inode);
4506		} else if (ext4_inode_is_fast_symlink(inode)) {
4507			inode->i_link = (char *)ei->i_data;
4508			inode->i_op = &ext4_fast_symlink_inode_operations;
4509			nd_terminate_link(ei->i_data, inode->i_size,
4510				sizeof(ei->i_data) - 1);
4511		} else {
4512			inode->i_op = &ext4_symlink_inode_operations;
4513			ext4_set_aops(inode);
4514		}
4515		inode_nohighmem(inode);
4516	} else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode) ||
4517	      S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode)) {
4518		inode->i_op = &ext4_special_inode_operations;
4519		if (raw_inode->i_block[0])
4520			init_special_inode(inode, inode->i_mode,
4521			   old_decode_dev(le32_to_cpu(raw_inode->i_block[0])));
4522		else
4523			init_special_inode(inode, inode->i_mode,
4524			   new_decode_dev(le32_to_cpu(raw_inode->i_block[1])));
4525	} else if (ino == EXT4_BOOT_LOADER_INO) {
4526		make_bad_inode(inode);
4527	} else {
4528		ret = -EFSCORRUPTED;
4529		EXT4_ERROR_INODE(inode, "bogus i_mode (%o)", inode->i_mode);
4530		goto bad_inode;
4531	}
4532	brelse(iloc.bh);
4533	ext4_set_inode_flags(inode);
4534	unlock_new_inode(inode);
4535	return inode;
4536
4537bad_inode:
4538	brelse(iloc.bh);
4539	iget_failed(inode);
4540	return ERR_PTR(ret);
4541}
4542
4543struct inode *ext4_iget_normal(struct super_block *sb, unsigned long ino)
4544{
4545	if (ino < EXT4_FIRST_INO(sb) && ino != EXT4_ROOT_INO)
4546		return ERR_PTR(-EFSCORRUPTED);
4547	return ext4_iget(sb, ino);
4548}
4549
4550static int ext4_inode_blocks_set(handle_t *handle,
4551				struct ext4_inode *raw_inode,
4552				struct ext4_inode_info *ei)
4553{
4554	struct inode *inode = &(ei->vfs_inode);
4555	u64 i_blocks = inode->i_blocks;
4556	struct super_block *sb = inode->i_sb;
4557
4558	if (i_blocks <= ~0U) {
4559		/*
4560		 * i_blocks can be represented in a 32 bit variable
4561		 * as multiple of 512 bytes
4562		 */
4563		raw_inode->i_blocks_lo   = cpu_to_le32(i_blocks);
4564		raw_inode->i_blocks_high = 0;
4565		ext4_clear_inode_flag(inode, EXT4_INODE_HUGE_FILE);
4566		return 0;
4567	}
4568	if (!ext4_has_feature_huge_file(sb))
4569		return -EFBIG;
4570
4571	if (i_blocks <= 0xffffffffffffULL) {
4572		/*
4573		 * i_blocks can be represented in a 48 bit variable
4574		 * as multiple of 512 bytes
4575		 */
4576		raw_inode->i_blocks_lo   = cpu_to_le32(i_blocks);
4577		raw_inode->i_blocks_high = cpu_to_le16(i_blocks >> 32);
4578		ext4_clear_inode_flag(inode, EXT4_INODE_HUGE_FILE);
4579	} else {
4580		ext4_set_inode_flag(inode, EXT4_INODE_HUGE_FILE);
4581		/* i_block is stored in file system block size */
4582		i_blocks = i_blocks >> (inode->i_blkbits - 9);
4583		raw_inode->i_blocks_lo   = cpu_to_le32(i_blocks);
4584		raw_inode->i_blocks_high = cpu_to_le16(i_blocks >> 32);
4585	}
4586	return 0;
4587}
4588
4589struct other_inode {
4590	unsigned long		orig_ino;
4591	struct ext4_inode	*raw_inode;
4592};
4593
4594static int other_inode_match(struct inode * inode, unsigned long ino,
4595			     void *data)
4596{
4597	struct other_inode *oi = (struct other_inode *) data;
4598
4599	if ((inode->i_ino != ino) ||
4600	    (inode->i_state & (I_FREEING | I_WILL_FREE | I_NEW |
4601			       I_DIRTY_SYNC | I_DIRTY_DATASYNC)) ||
4602	    ((inode->i_state & I_DIRTY_TIME) == 0))
4603		return 0;
4604	spin_lock(&inode->i_lock);
4605	if (((inode->i_state & (I_FREEING | I_WILL_FREE | I_NEW |
4606				I_DIRTY_SYNC | I_DIRTY_DATASYNC)) == 0) &&
4607	    (inode->i_state & I_DIRTY_TIME)) {
4608		struct ext4_inode_info	*ei = EXT4_I(inode);
4609
4610		inode->i_state &= ~(I_DIRTY_TIME | I_DIRTY_TIME_EXPIRED);
4611		spin_unlock(&inode->i_lock);
4612
4613		spin_lock(&ei->i_raw_lock);
4614		EXT4_INODE_SET_XTIME(i_ctime, inode, oi->raw_inode);
4615		EXT4_INODE_SET_XTIME(i_mtime, inode, oi->raw_inode);
4616		EXT4_INODE_SET_XTIME(i_atime, inode, oi->raw_inode);
4617		ext4_inode_csum_set(inode, oi->raw_inode, ei);
4618		spin_unlock(&ei->i_raw_lock);
4619		trace_ext4_other_inode_update_time(inode, oi->orig_ino);
4620		return -1;
4621	}
4622	spin_unlock(&inode->i_lock);
4623	return -1;
4624}
4625
4626/*
4627 * Opportunistically update the other time fields for other inodes in
4628 * the same inode table block.
4629 */
4630static void ext4_update_other_inodes_time(struct super_block *sb,
4631					  unsigned long orig_ino, char *buf)
4632{
4633	struct other_inode oi;
4634	unsigned long ino;
4635	int i, inodes_per_block = EXT4_SB(sb)->s_inodes_per_block;
4636	int inode_size = EXT4_INODE_SIZE(sb);
4637
4638	oi.orig_ino = orig_ino;
4639	/*
4640	 * Calculate the first inode in the inode table block.  Inode
4641	 * numbers are one-based.  That is, the first inode in a block
4642	 * (assuming 4k blocks and 256 byte inodes) is (n*16 + 1).
4643	 */
4644	ino = ((orig_ino - 1) & ~(inodes_per_block - 1)) + 1;
4645	for (i = 0; i < inodes_per_block; i++, ino++, buf += inode_size) {
4646		if (ino == orig_ino)
4647			continue;
4648		oi.raw_inode = (struct ext4_inode *) buf;
4649		(void) find_inode_nowait(sb, ino, other_inode_match, &oi);
4650	}
4651}
4652
4653/*
4654 * Post the struct inode info into an on-disk inode location in the
4655 * buffer-cache.  This gobbles the caller's reference to the
4656 * buffer_head in the inode location struct.
4657 *
4658 * The caller must have write access to iloc->bh.
4659 */
4660static int ext4_do_update_inode(handle_t *handle,
4661				struct inode *inode,
4662				struct ext4_iloc *iloc)
4663{
4664	struct ext4_inode *raw_inode = ext4_raw_inode(iloc);
4665	struct ext4_inode_info *ei = EXT4_I(inode);
4666	struct buffer_head *bh = iloc->bh;
4667	struct super_block *sb = inode->i_sb;
4668	int err = 0, rc, block;
4669	int need_datasync = 0, set_large_file = 0;
4670	uid_t i_uid;
4671	gid_t i_gid;
4672	projid_t i_projid;
4673
4674	spin_lock(&ei->i_raw_lock);
4675
4676	/* For fields not tracked in the in-memory inode,
4677	 * initialise them to zero for new inodes. */
4678	if (ext4_test_inode_state(inode, EXT4_STATE_NEW))
4679		memset(raw_inode, 0, EXT4_SB(inode->i_sb)->s_inode_size);
4680
4681	ext4_get_inode_flags(ei);
4682	raw_inode->i_mode = cpu_to_le16(inode->i_mode);
4683	i_uid = i_uid_read(inode);
4684	i_gid = i_gid_read(inode);
4685	i_projid = from_kprojid(&init_user_ns, ei->i_projid);
4686	if (!(test_opt(inode->i_sb, NO_UID32))) {
4687		raw_inode->i_uid_low = cpu_to_le16(low_16_bits(i_uid));
4688		raw_inode->i_gid_low = cpu_to_le16(low_16_bits(i_gid));
4689/*
4690 * Fix up interoperability with old kernels. Otherwise, old inodes get
4691 * re-used with the upper 16 bits of the uid/gid intact
4692 */
4693		if (!ei->i_dtime) {
4694			raw_inode->i_uid_high =
4695				cpu_to_le16(high_16_bits(i_uid));
4696			raw_inode->i_gid_high =
4697				cpu_to_le16(high_16_bits(i_gid));
4698		} else {
4699			raw_inode->i_uid_high = 0;
4700			raw_inode->i_gid_high = 0;
4701		}
4702	} else {
4703		raw_inode->i_uid_low = cpu_to_le16(fs_high2lowuid(i_uid));
4704		raw_inode->i_gid_low = cpu_to_le16(fs_high2lowgid(i_gid));
4705		raw_inode->i_uid_high = 0;
4706		raw_inode->i_gid_high = 0;
4707	}
4708	raw_inode->i_links_count = cpu_to_le16(inode->i_nlink);
4709
4710	EXT4_INODE_SET_XTIME(i_ctime, inode, raw_inode);
4711	EXT4_INODE_SET_XTIME(i_mtime, inode, raw_inode);
4712	EXT4_INODE_SET_XTIME(i_atime, inode, raw_inode);
4713	EXT4_EINODE_SET_XTIME(i_crtime, ei, raw_inode);
4714
4715	err = ext4_inode_blocks_set(handle, raw_inode, ei);
4716	if (err) {
4717		spin_unlock(&ei->i_raw_lock);
4718		goto out_brelse;
4719	}
4720	raw_inode->i_dtime = cpu_to_le32(ei->i_dtime);
4721	raw_inode->i_flags = cpu_to_le32(ei->i_flags & 0xFFFFFFFF);
4722	if (likely(!test_opt2(inode->i_sb, HURD_COMPAT)))
4723		raw_inode->i_file_acl_high =
4724			cpu_to_le16(ei->i_file_acl >> 32);
4725	raw_inode->i_file_acl_lo = cpu_to_le32(ei->i_file_acl);
4726	if (ei->i_disksize != ext4_isize(raw_inode)) {
4727		ext4_isize_set(raw_inode, ei->i_disksize);
4728		need_datasync = 1;
4729	}
4730	if (ei->i_disksize > 0x7fffffffULL) {
4731		if (!ext4_has_feature_large_file(sb) ||
 
 
4732				EXT4_SB(sb)->s_es->s_rev_level ==
4733		    cpu_to_le32(EXT4_GOOD_OLD_REV))
4734			set_large_file = 1;
 
 
 
 
 
 
 
 
 
 
 
 
4735	}
4736	raw_inode->i_generation = cpu_to_le32(inode->i_generation);
4737	if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode)) {
4738		if (old_valid_dev(inode->i_rdev)) {
4739			raw_inode->i_block[0] =
4740				cpu_to_le32(old_encode_dev(inode->i_rdev));
4741			raw_inode->i_block[1] = 0;
4742		} else {
4743			raw_inode->i_block[0] = 0;
4744			raw_inode->i_block[1] =
4745				cpu_to_le32(new_encode_dev(inode->i_rdev));
4746			raw_inode->i_block[2] = 0;
4747		}
4748	} else if (!ext4_has_inline_data(inode)) {
4749		for (block = 0; block < EXT4_N_BLOCKS; block++)
4750			raw_inode->i_block[block] = ei->i_data[block];
4751	}
4752
4753	if (likely(!test_opt2(inode->i_sb, HURD_COMPAT))) {
4754		raw_inode->i_disk_version = cpu_to_le32(inode->i_version);
4755		if (ei->i_extra_isize) {
4756			if (EXT4_FITS_IN_INODE(raw_inode, ei, i_version_hi))
4757				raw_inode->i_version_hi =
4758					cpu_to_le32(inode->i_version >> 32);
4759			raw_inode->i_extra_isize =
4760				cpu_to_le16(ei->i_extra_isize);
4761		}
4762	}
4763
4764	BUG_ON(!EXT4_HAS_RO_COMPAT_FEATURE(inode->i_sb,
4765			EXT4_FEATURE_RO_COMPAT_PROJECT) &&
4766	       i_projid != EXT4_DEF_PROJID);
4767
4768	if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE &&
4769	    EXT4_FITS_IN_INODE(raw_inode, ei, i_projid))
4770		raw_inode->i_projid = cpu_to_le32(i_projid);
4771
4772	ext4_inode_csum_set(inode, raw_inode, ei);
4773	spin_unlock(&ei->i_raw_lock);
4774	if (inode->i_sb->s_flags & MS_LAZYTIME)
4775		ext4_update_other_inodes_time(inode->i_sb, inode->i_ino,
4776					      bh->b_data);
4777
4778	BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
4779	rc = ext4_handle_dirty_metadata(handle, NULL, bh);
4780	if (!err)
4781		err = rc;
4782	ext4_clear_inode_state(inode, EXT4_STATE_NEW);
4783	if (set_large_file) {
4784		BUFFER_TRACE(EXT4_SB(sb)->s_sbh, "get write access");
4785		err = ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh);
4786		if (err)
4787			goto out_brelse;
4788		ext4_update_dynamic_rev(sb);
4789		ext4_set_feature_large_file(sb);
4790		ext4_handle_sync(handle);
4791		err = ext4_handle_dirty_super(handle, sb);
4792	}
4793	ext4_update_inode_fsync_trans(handle, inode, need_datasync);
4794out_brelse:
4795	brelse(bh);
4796	ext4_std_error(inode->i_sb, err);
4797	return err;
4798}
4799
4800/*
4801 * ext4_write_inode()
4802 *
4803 * We are called from a few places:
4804 *
4805 * - Within generic_file_aio_write() -> generic_write_sync() for O_SYNC files.
4806 *   Here, there will be no transaction running. We wait for any running
4807 *   transaction to commit.
4808 *
4809 * - Within flush work (sys_sync(), kupdate and such).
4810 *   We wait on commit, if told to.
4811 *
4812 * - Within iput_final() -> write_inode_now()
4813 *   We wait on commit, if told to.
4814 *
4815 * In all cases it is actually safe for us to return without doing anything,
4816 * because the inode has been copied into a raw inode buffer in
4817 * ext4_mark_inode_dirty().  This is a correctness thing for WB_SYNC_ALL
4818 * writeback.
4819 *
4820 * Note that we are absolutely dependent upon all inode dirtiers doing the
4821 * right thing: they *must* call mark_inode_dirty() after dirtying info in
4822 * which we are interested.
4823 *
4824 * It would be a bug for them to not do this.  The code:
4825 *
4826 *	mark_inode_dirty(inode)
4827 *	stuff();
4828 *	inode->i_size = expr;
4829 *
4830 * is in error because write_inode() could occur while `stuff()' is running,
4831 * and the new i_size will be lost.  Plus the inode will no longer be on the
4832 * superblock's dirty inode list.
4833 */
4834int ext4_write_inode(struct inode *inode, struct writeback_control *wbc)
4835{
4836	int err;
4837
4838	if (WARN_ON_ONCE(current->flags & PF_MEMALLOC))
4839		return 0;
4840
4841	if (EXT4_SB(inode->i_sb)->s_journal) {
4842		if (ext4_journal_current_handle()) {
4843			jbd_debug(1, "called recursively, non-PF_MEMALLOC!\n");
4844			dump_stack();
4845			return -EIO;
4846		}
4847
4848		/*
4849		 * No need to force transaction in WB_SYNC_NONE mode. Also
4850		 * ext4_sync_fs() will force the commit after everything is
4851		 * written.
4852		 */
4853		if (wbc->sync_mode != WB_SYNC_ALL || wbc->for_sync)
4854			return 0;
4855
4856		err = ext4_force_commit(inode->i_sb);
4857	} else {
4858		struct ext4_iloc iloc;
4859
4860		err = __ext4_get_inode_loc(inode, &iloc, 0);
4861		if (err)
4862			return err;
4863		/*
4864		 * sync(2) will flush the whole buffer cache. No need to do
4865		 * it here separately for each inode.
4866		 */
4867		if (wbc->sync_mode == WB_SYNC_ALL && !wbc->for_sync)
4868			sync_dirty_buffer(iloc.bh);
4869		if (buffer_req(iloc.bh) && !buffer_uptodate(iloc.bh)) {
4870			EXT4_ERROR_INODE_BLOCK(inode, iloc.bh->b_blocknr,
4871					 "IO error syncing inode");
4872			err = -EIO;
4873		}
4874		brelse(iloc.bh);
4875	}
4876	return err;
4877}
4878
4879/*
4880 * In data=journal mode ext4_journalled_invalidatepage() may fail to invalidate
4881 * buffers that are attached to a page stradding i_size and are undergoing
4882 * commit. In that case we have to wait for commit to finish and try again.
4883 */
4884static void ext4_wait_for_tail_page_commit(struct inode *inode)
4885{
4886	struct page *page;
4887	unsigned offset;
4888	journal_t *journal = EXT4_SB(inode->i_sb)->s_journal;
4889	tid_t commit_tid = 0;
4890	int ret;
4891
4892	offset = inode->i_size & (PAGE_SIZE - 1);
4893	/*
4894	 * All buffers in the last page remain valid? Then there's nothing to
4895	 * do. We do the check mainly to optimize the common PAGE_SIZE ==
4896	 * blocksize case
4897	 */
4898	if (offset > PAGE_SIZE - (1 << inode->i_blkbits))
4899		return;
4900	while (1) {
4901		page = find_lock_page(inode->i_mapping,
4902				      inode->i_size >> PAGE_SHIFT);
4903		if (!page)
4904			return;
4905		ret = __ext4_journalled_invalidatepage(page, offset,
4906						PAGE_SIZE - offset);
4907		unlock_page(page);
4908		put_page(page);
4909		if (ret != -EBUSY)
4910			return;
4911		commit_tid = 0;
4912		read_lock(&journal->j_state_lock);
4913		if (journal->j_committing_transaction)
4914			commit_tid = journal->j_committing_transaction->t_tid;
4915		read_unlock(&journal->j_state_lock);
4916		if (commit_tid)
4917			jbd2_log_wait_commit(journal, commit_tid);
4918	}
4919}
4920
4921/*
4922 * ext4_setattr()
4923 *
4924 * Called from notify_change.
4925 *
4926 * We want to trap VFS attempts to truncate the file as soon as
4927 * possible.  In particular, we want to make sure that when the VFS
4928 * shrinks i_size, we put the inode on the orphan list and modify
4929 * i_disksize immediately, so that during the subsequent flushing of
4930 * dirty pages and freeing of disk blocks, we can guarantee that any
4931 * commit will leave the blocks being flushed in an unused state on
4932 * disk.  (On recovery, the inode will get truncated and the blocks will
4933 * be freed, so we have a strong guarantee that no future commit will
4934 * leave these blocks visible to the user.)
4935 *
4936 * Another thing we have to assure is that if we are in ordered mode
4937 * and inode is still attached to the committing transaction, we must
4938 * we start writeout of all the dirty pages which are being truncated.
4939 * This way we are sure that all the data written in the previous
4940 * transaction are already on disk (truncate waits for pages under
4941 * writeback).
4942 *
4943 * Called with inode->i_mutex down.
4944 */
4945int ext4_setattr(struct dentry *dentry, struct iattr *attr)
4946{
4947	struct inode *inode = d_inode(dentry);
4948	int error, rc = 0;
4949	int orphan = 0;
4950	const unsigned int ia_valid = attr->ia_valid;
4951
4952	error = inode_change_ok(inode, attr);
4953	if (error)
4954		return error;
4955
4956	if (is_quota_modification(inode, attr)) {
4957		error = dquot_initialize(inode);
4958		if (error)
4959			return error;
4960	}
4961	if ((ia_valid & ATTR_UID && !uid_eq(attr->ia_uid, inode->i_uid)) ||
4962	    (ia_valid & ATTR_GID && !gid_eq(attr->ia_gid, inode->i_gid))) {
4963		handle_t *handle;
4964
4965		/* (user+group)*(old+new) structure, inode write (sb,
4966		 * inode block, ? - but truncate inode update has it) */
4967		handle = ext4_journal_start(inode, EXT4_HT_QUOTA,
4968			(EXT4_MAXQUOTAS_INIT_BLOCKS(inode->i_sb) +
4969			 EXT4_MAXQUOTAS_DEL_BLOCKS(inode->i_sb)) + 3);
4970		if (IS_ERR(handle)) {
4971			error = PTR_ERR(handle);
4972			goto err_out;
4973		}
4974		error = dquot_transfer(inode, attr);
4975		if (error) {
4976			ext4_journal_stop(handle);
4977			return error;
4978		}
4979		/* Update corresponding info in inode so that everything is in
4980		 * one transaction */
4981		if (attr->ia_valid & ATTR_UID)
4982			inode->i_uid = attr->ia_uid;
4983		if (attr->ia_valid & ATTR_GID)
4984			inode->i_gid = attr->ia_gid;
4985		error = ext4_mark_inode_dirty(handle, inode);
4986		ext4_journal_stop(handle);
4987	}
4988
4989	if (attr->ia_valid & ATTR_SIZE) {
4990		handle_t *handle;
4991		loff_t oldsize = inode->i_size;
4992		int shrink = (attr->ia_size <= inode->i_size);
4993
4994		if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) {
4995			struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
4996
4997			if (attr->ia_size > sbi->s_bitmap_maxbytes)
4998				return -EFBIG;
4999		}
5000		if (!S_ISREG(inode->i_mode))
5001			return -EINVAL;
5002
5003		if (IS_I_VERSION(inode) && attr->ia_size != inode->i_size)
5004			inode_inc_iversion(inode);
5005
5006		if (ext4_should_order_data(inode) &&
5007		    (attr->ia_size < inode->i_size)) {
5008			error = ext4_begin_ordered_truncate(inode,
 
5009							    attr->ia_size);
5010			if (error)
5011				goto err_out;
5012		}
5013		if (attr->ia_size != inode->i_size) {
5014			handle = ext4_journal_start(inode, EXT4_HT_INODE, 3);
5015			if (IS_ERR(handle)) {
5016				error = PTR_ERR(handle);
5017				goto err_out;
5018			}
5019			if (ext4_handle_valid(handle) && shrink) {
5020				error = ext4_orphan_add(handle, inode);
5021				orphan = 1;
5022			}
5023			/*
5024			 * Update c/mtime on truncate up, ext4_truncate() will
5025			 * update c/mtime in shrink case below
5026			 */
5027			if (!shrink) {
5028				inode->i_mtime = ext4_current_time(inode);
5029				inode->i_ctime = inode->i_mtime;
5030			}
5031			down_write(&EXT4_I(inode)->i_data_sem);
5032			EXT4_I(inode)->i_disksize = attr->ia_size;
5033			rc = ext4_mark_inode_dirty(handle, inode);
5034			if (!error)
5035				error = rc;
5036			/*
5037			 * We have to update i_size under i_data_sem together
5038			 * with i_disksize to avoid races with writeback code
5039			 * running ext4_wb_update_i_disksize().
5040			 */
5041			if (!error)
5042				i_size_write(inode, attr->ia_size);
5043			up_write(&EXT4_I(inode)->i_data_sem);
5044			ext4_journal_stop(handle);
5045			if (error) {
5046				if (orphan)
5047					ext4_orphan_del(NULL, inode);
5048				goto err_out;
5049			}
5050		}
5051		if (!shrink)
5052			pagecache_isize_extended(inode, oldsize, inode->i_size);
5053
5054		/*
5055		 * Blocks are going to be removed from the inode. Wait
5056		 * for dio in flight.  Temporarily disable
5057		 * dioread_nolock to prevent livelock.
5058		 */
5059		if (orphan) {
5060			if (!ext4_should_journal_data(inode)) {
5061				ext4_inode_block_unlocked_dio(inode);
5062				inode_dio_wait(inode);
5063				ext4_inode_resume_unlocked_dio(inode);
5064			} else
5065				ext4_wait_for_tail_page_commit(inode);
5066		}
5067		down_write(&EXT4_I(inode)->i_mmap_sem);
5068		/*
5069		 * Truncate pagecache after we've waited for commit
5070		 * in data=journal mode to make pages freeable.
5071		 */
5072		truncate_pagecache(inode, inode->i_size);
5073		if (shrink)
5074			ext4_truncate(inode);
5075		up_write(&EXT4_I(inode)->i_mmap_sem);
5076	}
 
 
 
 
 
 
5077
5078	if (!rc) {
5079		setattr_copy(inode, attr);
5080		mark_inode_dirty(inode);
5081	}
5082
5083	/*
5084	 * If the call to ext4_truncate failed to get a transaction handle at
5085	 * all, we need to clean up the in-core orphan list manually.
5086	 */
5087	if (orphan && inode->i_nlink)
5088		ext4_orphan_del(NULL, inode);
5089
5090	if (!rc && (ia_valid & ATTR_MODE))
5091		rc = posix_acl_chmod(inode, inode->i_mode);
5092
5093err_out:
5094	ext4_std_error(inode->i_sb, error);
5095	if (!error)
5096		error = rc;
5097	return error;
5098}
5099
5100int ext4_getattr(struct vfsmount *mnt, struct dentry *dentry,
5101		 struct kstat *stat)
5102{
5103	struct inode *inode;
5104	unsigned long long delalloc_blocks;
5105
5106	inode = d_inode(dentry);
5107	generic_fillattr(inode, stat);
5108
5109	/*
5110	 * If there is inline data in the inode, the inode will normally not
5111	 * have data blocks allocated (it may have an external xattr block).
5112	 * Report at least one sector for such files, so tools like tar, rsync,
5113	 * others doen't incorrectly think the file is completely sparse.
5114	 */
5115	if (unlikely(ext4_has_inline_data(inode)))
5116		stat->blocks += (stat->size + 511) >> 9;
5117
5118	/*
5119	 * We can't update i_blocks if the block allocation is delayed
5120	 * otherwise in the case of system crash before the real block
5121	 * allocation is done, we will have i_blocks inconsistent with
5122	 * on-disk file blocks.
5123	 * We always keep i_blocks updated together with real
5124	 * allocation. But to not confuse with user, stat
5125	 * will return the blocks that include the delayed allocation
5126	 * blocks for this file.
5127	 */
5128	delalloc_blocks = EXT4_C2B(EXT4_SB(inode->i_sb),
5129				   EXT4_I(inode)->i_reserved_data_blocks);
5130	stat->blocks += delalloc_blocks << (inode->i_sb->s_blocksize_bits - 9);
5131	return 0;
5132}
5133
5134static int ext4_index_trans_blocks(struct inode *inode, int lblocks,
5135				   int pextents)
5136{
5137	if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
5138		return ext4_ind_trans_blocks(inode, lblocks);
5139	return ext4_ext_index_trans_blocks(inode, pextents);
5140}
5141
5142/*
5143 * Account for index blocks, block groups bitmaps and block group
5144 * descriptor blocks if modify datablocks and index blocks
5145 * worse case, the indexs blocks spread over different block groups
5146 *
5147 * If datablocks are discontiguous, they are possible to spread over
5148 * different block groups too. If they are contiguous, with flexbg,
5149 * they could still across block group boundary.
5150 *
5151 * Also account for superblock, inode, quota and xattr blocks
5152 */
5153static int ext4_meta_trans_blocks(struct inode *inode, int lblocks,
5154				  int pextents)
5155{
5156	ext4_group_t groups, ngroups = ext4_get_groups_count(inode->i_sb);
5157	int gdpblocks;
5158	int idxblocks;
5159	int ret = 0;
5160
5161	/*
5162	 * How many index blocks need to touch to map @lblocks logical blocks
5163	 * to @pextents physical extents?
5164	 */
5165	idxblocks = ext4_index_trans_blocks(inode, lblocks, pextents);
5166
5167	ret = idxblocks;
5168
5169	/*
5170	 * Now let's see how many group bitmaps and group descriptors need
5171	 * to account
5172	 */
5173	groups = idxblocks + pextents;
5174	gdpblocks = groups;
5175	if (groups > ngroups)
5176		groups = ngroups;
5177	if (groups > EXT4_SB(inode->i_sb)->s_gdb_count)
5178		gdpblocks = EXT4_SB(inode->i_sb)->s_gdb_count;
5179
5180	/* bitmaps and block group descriptor blocks */
5181	ret += groups + gdpblocks;
5182
5183	/* Blocks for super block, inode, quota and xattr blocks */
5184	ret += EXT4_META_TRANS_BLOCKS(inode->i_sb);
5185
5186	return ret;
5187}
5188
5189/*
5190 * Calculate the total number of credits to reserve to fit
5191 * the modification of a single pages into a single transaction,
5192 * which may include multiple chunks of block allocations.
5193 *
5194 * This could be called via ext4_write_begin()
5195 *
5196 * We need to consider the worse case, when
5197 * one new block per extent.
5198 */
5199int ext4_writepage_trans_blocks(struct inode *inode)
5200{
5201	int bpp = ext4_journal_blocks_per_page(inode);
5202	int ret;
5203
5204	ret = ext4_meta_trans_blocks(inode, bpp, bpp);
5205
5206	/* Account for data blocks for journalled mode */
5207	if (ext4_should_journal_data(inode))
5208		ret += bpp;
5209	return ret;
5210}
5211
5212/*
5213 * Calculate the journal credits for a chunk of data modification.
5214 *
5215 * This is called from DIO, fallocate or whoever calling
5216 * ext4_map_blocks() to map/allocate a chunk of contiguous disk blocks.
5217 *
5218 * journal buffers for data blocks are not included here, as DIO
5219 * and fallocate do no need to journal data buffers.
5220 */
5221int ext4_chunk_trans_blocks(struct inode *inode, int nrblocks)
5222{
5223	return ext4_meta_trans_blocks(inode, nrblocks, 1);
5224}
5225
5226/*
5227 * The caller must have previously called ext4_reserve_inode_write().
5228 * Give this, we know that the caller already has write access to iloc->bh.
5229 */
5230int ext4_mark_iloc_dirty(handle_t *handle,
5231			 struct inode *inode, struct ext4_iloc *iloc)
5232{
5233	int err = 0;
5234
5235	if (IS_I_VERSION(inode))
5236		inode_inc_iversion(inode);
5237
5238	/* the do_update_inode consumes one bh->b_count */
5239	get_bh(iloc->bh);
5240
5241	/* ext4_do_update_inode() does jbd2_journal_dirty_metadata */
5242	err = ext4_do_update_inode(handle, inode, iloc);
5243	put_bh(iloc->bh);
5244	return err;
5245}
5246
5247/*
5248 * On success, We end up with an outstanding reference count against
5249 * iloc->bh.  This _must_ be cleaned up later.
5250 */
5251
5252int
5253ext4_reserve_inode_write(handle_t *handle, struct inode *inode,
5254			 struct ext4_iloc *iloc)
5255{
5256	int err;
5257
5258	err = ext4_get_inode_loc(inode, iloc);
5259	if (!err) {
5260		BUFFER_TRACE(iloc->bh, "get_write_access");
5261		err = ext4_journal_get_write_access(handle, iloc->bh);
5262		if (err) {
5263			brelse(iloc->bh);
5264			iloc->bh = NULL;
5265		}
5266	}
5267	ext4_std_error(inode->i_sb, err);
5268	return err;
5269}
5270
5271/*
5272 * Expand an inode by new_extra_isize bytes.
5273 * Returns 0 on success or negative error number on failure.
5274 */
5275static int ext4_expand_extra_isize(struct inode *inode,
5276				   unsigned int new_extra_isize,
5277				   struct ext4_iloc iloc,
5278				   handle_t *handle)
5279{
5280	struct ext4_inode *raw_inode;
5281	struct ext4_xattr_ibody_header *header;
5282
5283	if (EXT4_I(inode)->i_extra_isize >= new_extra_isize)
5284		return 0;
5285
5286	raw_inode = ext4_raw_inode(&iloc);
5287
5288	header = IHDR(inode, raw_inode);
5289
5290	/* No extended attributes present */
5291	if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR) ||
5292	    header->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC)) {
5293		memset((void *)raw_inode + EXT4_GOOD_OLD_INODE_SIZE, 0,
5294			new_extra_isize);
5295		EXT4_I(inode)->i_extra_isize = new_extra_isize;
5296		return 0;
5297	}
5298
5299	/* try to expand with EAs present */
5300	return ext4_expand_extra_isize_ea(inode, new_extra_isize,
5301					  raw_inode, handle);
5302}
5303
5304/*
5305 * What we do here is to mark the in-core inode as clean with respect to inode
5306 * dirtiness (it may still be data-dirty).
5307 * This means that the in-core inode may be reaped by prune_icache
5308 * without having to perform any I/O.  This is a very good thing,
5309 * because *any* task may call prune_icache - even ones which
5310 * have a transaction open against a different journal.
5311 *
5312 * Is this cheating?  Not really.  Sure, we haven't written the
5313 * inode out, but prune_icache isn't a user-visible syncing function.
5314 * Whenever the user wants stuff synced (sys_sync, sys_msync, sys_fsync)
5315 * we start and wait on commits.
5316 */
5317int ext4_mark_inode_dirty(handle_t *handle, struct inode *inode)
5318{
5319	struct ext4_iloc iloc;
5320	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
5321	static unsigned int mnt_count;
5322	int err, ret;
5323
5324	might_sleep();
5325	trace_ext4_mark_inode_dirty(inode, _RET_IP_);
5326	err = ext4_reserve_inode_write(handle, inode, &iloc);
5327	if (err)
5328		return err;
5329	if (ext4_handle_valid(handle) &&
5330	    EXT4_I(inode)->i_extra_isize < sbi->s_want_extra_isize &&
5331	    !ext4_test_inode_state(inode, EXT4_STATE_NO_EXPAND)) {
5332		/*
5333		 * We need extra buffer credits since we may write into EA block
5334		 * with this same handle. If journal_extend fails, then it will
5335		 * only result in a minor loss of functionality for that inode.
5336		 * If this is felt to be critical, then e2fsck should be run to
5337		 * force a large enough s_min_extra_isize.
5338		 */
5339		if ((jbd2_journal_extend(handle,
5340			     EXT4_DATA_TRANS_BLOCKS(inode->i_sb))) == 0) {
5341			ret = ext4_expand_extra_isize(inode,
5342						      sbi->s_want_extra_isize,
5343						      iloc, handle);
5344			if (ret) {
5345				ext4_set_inode_state(inode,
5346						     EXT4_STATE_NO_EXPAND);
5347				if (mnt_count !=
5348					le16_to_cpu(sbi->s_es->s_mnt_count)) {
5349					ext4_warning(inode->i_sb,
5350					"Unable to expand inode %lu. Delete"
5351					" some EAs or run e2fsck.",
5352					inode->i_ino);
5353					mnt_count =
5354					  le16_to_cpu(sbi->s_es->s_mnt_count);
5355				}
5356			}
5357		}
5358	}
5359	return ext4_mark_iloc_dirty(handle, inode, &iloc);
 
 
5360}
5361
5362/*
5363 * ext4_dirty_inode() is called from __mark_inode_dirty()
5364 *
5365 * We're really interested in the case where a file is being extended.
5366 * i_size has been changed by generic_commit_write() and we thus need
5367 * to include the updated inode in the current transaction.
5368 *
5369 * Also, dquot_alloc_block() will always dirty the inode when blocks
5370 * are allocated to the file.
5371 *
5372 * If the inode is marked synchronous, we don't honour that here - doing
5373 * so would cause a commit on atime updates, which we don't bother doing.
5374 * We handle synchronous inodes at the highest possible level.
5375 *
5376 * If only the I_DIRTY_TIME flag is set, we can skip everything.  If
5377 * I_DIRTY_TIME and I_DIRTY_SYNC is set, the only inode fields we need
5378 * to copy into the on-disk inode structure are the timestamp files.
5379 */
5380void ext4_dirty_inode(struct inode *inode, int flags)
5381{
5382	handle_t *handle;
5383
5384	if (flags == I_DIRTY_TIME)
5385		return;
5386	handle = ext4_journal_start(inode, EXT4_HT_INODE, 2);
5387	if (IS_ERR(handle))
5388		goto out;
5389
5390	ext4_mark_inode_dirty(handle, inode);
5391
5392	ext4_journal_stop(handle);
5393out:
5394	return;
5395}
5396
5397#if 0
5398/*
5399 * Bind an inode's backing buffer_head into this transaction, to prevent
5400 * it from being flushed to disk early.  Unlike
5401 * ext4_reserve_inode_write, this leaves behind no bh reference and
5402 * returns no iloc structure, so the caller needs to repeat the iloc
5403 * lookup to mark the inode dirty later.
5404 */
5405static int ext4_pin_inode(handle_t *handle, struct inode *inode)
5406{
5407	struct ext4_iloc iloc;
5408
5409	int err = 0;
5410	if (handle) {
5411		err = ext4_get_inode_loc(inode, &iloc);
5412		if (!err) {
5413			BUFFER_TRACE(iloc.bh, "get_write_access");
5414			err = jbd2_journal_get_write_access(handle, iloc.bh);
5415			if (!err)
5416				err = ext4_handle_dirty_metadata(handle,
5417								 NULL,
5418								 iloc.bh);
5419			brelse(iloc.bh);
5420		}
5421	}
5422	ext4_std_error(inode->i_sb, err);
5423	return err;
5424}
5425#endif
5426
5427int ext4_change_inode_journal_flag(struct inode *inode, int val)
5428{
5429	journal_t *journal;
5430	handle_t *handle;
5431	int err;
5432
5433	/*
5434	 * We have to be very careful here: changing a data block's
5435	 * journaling status dynamically is dangerous.  If we write a
5436	 * data block to the journal, change the status and then delete
5437	 * that block, we risk forgetting to revoke the old log record
5438	 * from the journal and so a subsequent replay can corrupt data.
5439	 * So, first we make sure that the journal is empty and that
5440	 * nobody is changing anything.
5441	 */
5442
5443	journal = EXT4_JOURNAL(inode);
5444	if (!journal)
5445		return 0;
5446	if (is_journal_aborted(journal))
5447		return -EROFS;
5448	/* We have to allocate physical blocks for delalloc blocks
5449	 * before flushing journal. otherwise delalloc blocks can not
5450	 * be allocated any more. even more truncate on delalloc blocks
5451	 * could trigger BUG by flushing delalloc blocks in journal.
5452	 * There is no delalloc block in non-journal data mode.
5453	 */
5454	if (val && test_opt(inode->i_sb, DELALLOC)) {
5455		err = ext4_alloc_da_blocks(inode);
5456		if (err < 0)
5457			return err;
5458	}
5459
5460	/* Wait for all existing dio workers */
5461	ext4_inode_block_unlocked_dio(inode);
5462	inode_dio_wait(inode);
5463
5464	jbd2_journal_lock_updates(journal);
5465
5466	/*
5467	 * OK, there are no updates running now, and all cached data is
5468	 * synced to disk.  We are now in a completely consistent state
5469	 * which doesn't have anything in the journal, and we know that
5470	 * no filesystem updates are running, so it is safe to modify
5471	 * the inode's in-core data-journaling state flag now.
5472	 */
5473
5474	if (val)
5475		ext4_set_inode_flag(inode, EXT4_INODE_JOURNAL_DATA);
5476	else {
5477		err = jbd2_journal_flush(journal);
5478		if (err < 0) {
5479			jbd2_journal_unlock_updates(journal);
5480			ext4_inode_resume_unlocked_dio(inode);
5481			return err;
5482		}
5483		ext4_clear_inode_flag(inode, EXT4_INODE_JOURNAL_DATA);
5484	}
5485	ext4_set_aops(inode);
5486
5487	jbd2_journal_unlock_updates(journal);
5488	ext4_inode_resume_unlocked_dio(inode);
5489
5490	/* Finally we can mark the inode as dirty. */
5491
5492	handle = ext4_journal_start(inode, EXT4_HT_INODE, 1);
5493	if (IS_ERR(handle))
5494		return PTR_ERR(handle);
5495
5496	err = ext4_mark_inode_dirty(handle, inode);
5497	ext4_handle_sync(handle);
5498	ext4_journal_stop(handle);
5499	ext4_std_error(inode->i_sb, err);
5500
5501	return err;
5502}
5503
5504static int ext4_bh_unmapped(handle_t *handle, struct buffer_head *bh)
5505{
5506	return !buffer_mapped(bh);
5507}
5508
5509int ext4_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
5510{
5511	struct page *page = vmf->page;
5512	loff_t size;
5513	unsigned long len;
5514	int ret;
5515	struct file *file = vma->vm_file;
5516	struct inode *inode = file_inode(file);
5517	struct address_space *mapping = inode->i_mapping;
5518	handle_t *handle;
5519	get_block_t *get_block;
5520	int retries = 0;
5521
5522	sb_start_pagefault(inode->i_sb);
5523	file_update_time(vma->vm_file);
5524
5525	down_read(&EXT4_I(inode)->i_mmap_sem);
5526	/* Delalloc case is easy... */
5527	if (test_opt(inode->i_sb, DELALLOC) &&
5528	    !ext4_should_journal_data(inode) &&
5529	    !ext4_nonda_switch(inode->i_sb)) {
5530		do {
5531			ret = block_page_mkwrite(vma, vmf,
5532						   ext4_da_get_block_prep);
5533		} while (ret == -ENOSPC &&
5534		       ext4_should_retry_alloc(inode->i_sb, &retries));
5535		goto out_ret;
5536	}
5537
5538	lock_page(page);
5539	size = i_size_read(inode);
5540	/* Page got truncated from under us? */
5541	if (page->mapping != mapping || page_offset(page) > size) {
5542		unlock_page(page);
5543		ret = VM_FAULT_NOPAGE;
5544		goto out;
5545	}
5546
5547	if (page->index == size >> PAGE_SHIFT)
5548		len = size & ~PAGE_MASK;
5549	else
5550		len = PAGE_SIZE;
5551	/*
5552	 * Return if we have all the buffers mapped. This avoids the need to do
5553	 * journal_start/journal_stop which can block and take a long time
5554	 */
5555	if (page_has_buffers(page)) {
5556		if (!ext4_walk_page_buffers(NULL, page_buffers(page),
5557					    0, len, NULL,
5558					    ext4_bh_unmapped)) {
5559			/* Wait so that we don't change page under IO */
5560			wait_for_stable_page(page);
5561			ret = VM_FAULT_LOCKED;
5562			goto out;
5563		}
5564	}
5565	unlock_page(page);
5566	/* OK, we need to fill the hole... */
5567	if (ext4_should_dioread_nolock(inode))
5568		get_block = ext4_get_block_unwritten;
5569	else
5570		get_block = ext4_get_block;
5571retry_alloc:
5572	handle = ext4_journal_start(inode, EXT4_HT_WRITE_PAGE,
5573				    ext4_writepage_trans_blocks(inode));
5574	if (IS_ERR(handle)) {
5575		ret = VM_FAULT_SIGBUS;
5576		goto out;
5577	}
5578	ret = block_page_mkwrite(vma, vmf, get_block);
5579	if (!ret && ext4_should_journal_data(inode)) {
5580		if (ext4_walk_page_buffers(handle, page_buffers(page), 0,
5581			  PAGE_SIZE, NULL, do_journal_get_write_access)) {
5582			unlock_page(page);
5583			ret = VM_FAULT_SIGBUS;
5584			ext4_journal_stop(handle);
5585			goto out;
5586		}
5587		ext4_set_inode_state(inode, EXT4_STATE_JDATA);
5588	}
5589	ext4_journal_stop(handle);
5590	if (ret == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
5591		goto retry_alloc;
5592out_ret:
5593	ret = block_page_mkwrite_return(ret);
5594out:
5595	up_read(&EXT4_I(inode)->i_mmap_sem);
5596	sb_end_pagefault(inode->i_sb);
5597	return ret;
5598}
5599
5600int ext4_filemap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
5601{
5602	struct inode *inode = file_inode(vma->vm_file);
5603	int err;
5604
5605	down_read(&EXT4_I(inode)->i_mmap_sem);
5606	err = filemap_fault(vma, vmf);
5607	up_read(&EXT4_I(inode)->i_mmap_sem);
5608
5609	return err;
5610}
5611
5612/*
5613 * Find the first extent at or after @lblk in an inode that is not a hole.
5614 * Search for @map_len blocks at most. The extent is returned in @result.
5615 *
5616 * The function returns 1 if we found an extent. The function returns 0 in
5617 * case there is no extent at or after @lblk and in that case also sets
5618 * @result->es_len to 0. In case of error, the error code is returned.
5619 */
5620int ext4_get_next_extent(struct inode *inode, ext4_lblk_t lblk,
5621			 unsigned int map_len, struct extent_status *result)
5622{
5623	struct ext4_map_blocks map;
5624	struct extent_status es = {};
5625	int ret;
5626
5627	map.m_lblk = lblk;
5628	map.m_len = map_len;
5629
5630	/*
5631	 * For non-extent based files this loop may iterate several times since
5632	 * we do not determine full hole size.
5633	 */
5634	while (map.m_len > 0) {
5635		ret = ext4_map_blocks(NULL, inode, &map, 0);
5636		if (ret < 0)
5637			return ret;
5638		/* There's extent covering m_lblk? Just return it. */
5639		if (ret > 0) {
5640			int status;
5641
5642			ext4_es_store_pblock(result, map.m_pblk);
5643			result->es_lblk = map.m_lblk;
5644			result->es_len = map.m_len;
5645			if (map.m_flags & EXT4_MAP_UNWRITTEN)
5646				status = EXTENT_STATUS_UNWRITTEN;
5647			else
5648				status = EXTENT_STATUS_WRITTEN;
5649			ext4_es_store_status(result, status);
5650			return 1;
5651		}
5652		ext4_es_find_delayed_extent_range(inode, map.m_lblk,
5653						  map.m_lblk + map.m_len - 1,
5654						  &es);
5655		/* Is delalloc data before next block in extent tree? */
5656		if (es.es_len && es.es_lblk < map.m_lblk + map.m_len) {
5657			ext4_lblk_t offset = 0;
5658
5659			if (es.es_lblk < lblk)
5660				offset = lblk - es.es_lblk;
5661			result->es_lblk = es.es_lblk + offset;
5662			ext4_es_store_pblock(result,
5663					     ext4_es_pblock(&es) + offset);
5664			result->es_len = es.es_len - offset;
5665			ext4_es_store_status(result, ext4_es_status(&es));
5666
5667			return 1;
5668		}
5669		/* There's a hole at m_lblk, advance us after it */
5670		map.m_lblk += map.m_len;
5671		map_len -= map.m_len;
5672		map.m_len = map_len;
5673		cond_resched();
5674	}
5675	result->es_len = 0;
5676	return 0;
5677}