2 * linux/fs/ext4/inode.c
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)
11 * linux/fs/minix/inode.c
13 * Copyright (C) 1991, 1992 Linus Torvalds
15 * Goal-directed block allocation by Stephen Tweedie
16 * (sct@redhat.com), 1993, 1998
17 * Big-endian to little-endian byte-swapping/bitmaps by
18 * David S. Miller (davem@caip.rutgers.edu), 1995
19 * 64-bit file support on 64-bit platforms by Jakub Jelinek
20 * (jj@sunsite.ms.mff.cuni.cz)
22 * Assorted race fixes, rewrite of ext4_get_block() by Al Viro, 2000
25 #include <linux/module.h>
27 #include <linux/time.h>
28 #include <linux/jbd2.h>
29 #include <linux/highuid.h>
30 #include <linux/pagemap.h>
31 #include <linux/quotaops.h>
32 #include <linux/string.h>
33 #include <linux/buffer_head.h>
34 #include <linux/writeback.h>
35 #include <linux/pagevec.h>
36 #include <linux/mpage.h>
37 #include <linux/namei.h>
38 #include <linux/uio.h>
39 #include <linux/bio.h>
40 #include <linux/workqueue.h>
42 #include "ext4_jbd2.h"
45 #include "ext4_extents.h"
47 #include <trace/events/ext4.h>
49 #define MPAGE_DA_EXTENT_TAIL 0x01
51 static inline int ext4_begin_ordered_truncate(struct inode *inode,
54 return jbd2_journal_begin_ordered_truncate(
55 EXT4_SB(inode->i_sb)->s_journal,
56 &EXT4_I(inode)->jinode,
60 static void ext4_invalidatepage(struct page *page, unsigned long offset);
63 * Test whether an inode is a fast symlink.
65 static int ext4_inode_is_fast_symlink(struct inode *inode)
67 int ea_blocks = EXT4_I(inode)->i_file_acl ?
68 (inode->i_sb->s_blocksize >> 9) : 0;
70 return (S_ISLNK(inode->i_mode) && inode->i_blocks - ea_blocks == 0);
74 * Work out how many blocks we need to proceed with the next chunk of a
75 * truncate transaction.
77 static unsigned long blocks_for_truncate(struct inode *inode)
81 needed = inode->i_blocks >> (inode->i_sb->s_blocksize_bits - 9);
83 /* Give ourselves just enough room to cope with inodes in which
84 * i_blocks is corrupt: we've seen disk corruptions in the past
85 * which resulted in random data in an inode which looked enough
86 * like a regular file for ext4 to try to delete it. Things
87 * will go a bit crazy if that happens, but at least we should
88 * try not to panic the whole kernel. */
92 /* But we need to bound the transaction so we don't overflow the
94 if (needed > EXT4_MAX_TRANS_DATA)
95 needed = EXT4_MAX_TRANS_DATA;
97 return EXT4_DATA_TRANS_BLOCKS(inode->i_sb) + needed;
101 * Truncate transactions can be complex and absolutely huge. So we need to
102 * be able to restart the transaction at a conventient checkpoint to make
103 * sure we don't overflow the journal.
105 * start_transaction gets us a new handle for a truncate transaction,
106 * and extend_transaction tries to extend the existing one a bit. If
107 * extend fails, we need to propagate the failure up and restart the
108 * transaction in the top-level truncate loop. --sct
110 static handle_t *start_transaction(struct inode *inode)
114 result = ext4_journal_start(inode, blocks_for_truncate(inode));
118 ext4_std_error(inode->i_sb, PTR_ERR(result));
123 * Try to extend this transaction for the purposes of truncation.
125 * Returns 0 if we managed to create more room. If we can't create more
126 * room, and the transaction must be restarted we return 1.
128 static int try_to_extend_transaction(handle_t *handle, struct inode *inode)
130 if (!ext4_handle_valid(handle))
132 if (ext4_handle_has_enough_credits(handle, EXT4_RESERVE_TRANS_BLOCKS+1))
134 if (!ext4_journal_extend(handle, blocks_for_truncate(inode)))
140 * Restart the transaction associated with *handle. This does a commit,
141 * so before we call here everything must be consistently dirtied against
144 int ext4_truncate_restart_trans(handle_t *handle, struct inode *inode,
150 * Drop i_data_sem to avoid deadlock with ext4_get_blocks At this
151 * moment, get_block can be called only for blocks inside i_size since
152 * page cache has been already dropped and writes are blocked by
153 * i_mutex. So we can safely drop the i_data_sem here.
155 BUG_ON(EXT4_JOURNAL(inode) == NULL);
156 jbd_debug(2, "restarting handle %p\n", handle);
157 up_write(&EXT4_I(inode)->i_data_sem);
158 ret = ext4_journal_restart(handle, blocks_for_truncate(inode));
159 down_write(&EXT4_I(inode)->i_data_sem);
160 ext4_discard_preallocations(inode);
166 * Called at the last iput() if i_nlink is zero.
168 void ext4_delete_inode(struct inode *inode)
173 if (ext4_should_order_data(inode))
174 ext4_begin_ordered_truncate(inode, 0);
175 truncate_inode_pages(&inode->i_data, 0);
177 if (is_bad_inode(inode))
180 handle = ext4_journal_start(inode, blocks_for_truncate(inode)+3);
181 if (IS_ERR(handle)) {
182 ext4_std_error(inode->i_sb, PTR_ERR(handle));
184 * If we're going to skip the normal cleanup, we still need to
185 * make sure that the in-core orphan linked list is properly
188 ext4_orphan_del(NULL, inode);
193 ext4_handle_sync(handle);
195 err = ext4_mark_inode_dirty(handle, inode);
197 ext4_warning(inode->i_sb, __func__,
198 "couldn't mark inode dirty (err %d)", err);
202 ext4_truncate(inode);
205 * ext4_ext_truncate() doesn't reserve any slop when it
206 * restarts journal transactions; therefore there may not be
207 * enough credits left in the handle to remove the inode from
208 * the orphan list and set the dtime field.
210 if (!ext4_handle_has_enough_credits(handle, 3)) {
211 err = ext4_journal_extend(handle, 3);
213 err = ext4_journal_restart(handle, 3);
215 ext4_warning(inode->i_sb, __func__,
216 "couldn't extend journal (err %d)", err);
218 ext4_journal_stop(handle);
224 * Kill off the orphan record which ext4_truncate created.
225 * AKPM: I think this can be inside the above `if'.
226 * Note that ext4_orphan_del() has to be able to cope with the
227 * deletion of a non-existent orphan - this is because we don't
228 * know if ext4_truncate() actually created an orphan record.
229 * (Well, we could do this if we need to, but heck - it works)
231 ext4_orphan_del(handle, inode);
232 EXT4_I(inode)->i_dtime = get_seconds();
235 * One subtle ordering requirement: if anything has gone wrong
236 * (transaction abort, IO errors, whatever), then we can still
237 * do these next steps (the fs will already have been marked as
238 * having errors), but we can't free the inode if the mark_dirty
241 if (ext4_mark_inode_dirty(handle, inode))
242 /* If that failed, just do the required in-core inode clear. */
245 ext4_free_inode(handle, inode);
246 ext4_journal_stop(handle);
249 clear_inode(inode); /* We must guarantee clearing of inode... */
255 struct buffer_head *bh;
258 static inline void add_chain(Indirect *p, struct buffer_head *bh, __le32 *v)
260 p->key = *(p->p = v);
265 * ext4_block_to_path - parse the block number into array of offsets
266 * @inode: inode in question (we are only interested in its superblock)
267 * @i_block: block number to be parsed
268 * @offsets: array to store the offsets in
269 * @boundary: set this non-zero if the referred-to block is likely to be
270 * followed (on disk) by an indirect block.
272 * To store the locations of file's data ext4 uses a data structure common
273 * for UNIX filesystems - tree of pointers anchored in the inode, with
274 * data blocks at leaves and indirect blocks in intermediate nodes.
275 * This function translates the block number into path in that tree -
276 * return value is the path length and @offsets[n] is the offset of
277 * pointer to (n+1)th node in the nth one. If @block is out of range
278 * (negative or too large) warning is printed and zero returned.
280 * Note: function doesn't find node addresses, so no IO is needed. All
281 * we need to know is the capacity of indirect blocks (taken from the
286 * Portability note: the last comparison (check that we fit into triple
287 * indirect block) is spelled differently, because otherwise on an
288 * architecture with 32-bit longs and 8Kb pages we might get into trouble
289 * if our filesystem had 8Kb blocks. We might use long long, but that would
290 * kill us on x86. Oh, well, at least the sign propagation does not matter -
291 * i_block would have to be negative in the very beginning, so we would not
295 static int ext4_block_to_path(struct inode *inode,
297 ext4_lblk_t offsets[4], int *boundary)
299 int ptrs = EXT4_ADDR_PER_BLOCK(inode->i_sb);
300 int ptrs_bits = EXT4_ADDR_PER_BLOCK_BITS(inode->i_sb);
301 const long direct_blocks = EXT4_NDIR_BLOCKS,
302 indirect_blocks = ptrs,
303 double_blocks = (1 << (ptrs_bits * 2));
307 if (i_block < direct_blocks) {
308 offsets[n++] = i_block;
309 final = direct_blocks;
310 } else if ((i_block -= direct_blocks) < indirect_blocks) {
311 offsets[n++] = EXT4_IND_BLOCK;
312 offsets[n++] = i_block;
314 } else if ((i_block -= indirect_blocks) < double_blocks) {
315 offsets[n++] = EXT4_DIND_BLOCK;
316 offsets[n++] = i_block >> ptrs_bits;
317 offsets[n++] = i_block & (ptrs - 1);
319 } else if (((i_block -= double_blocks) >> (ptrs_bits * 2)) < ptrs) {
320 offsets[n++] = EXT4_TIND_BLOCK;
321 offsets[n++] = i_block >> (ptrs_bits * 2);
322 offsets[n++] = (i_block >> ptrs_bits) & (ptrs - 1);
323 offsets[n++] = i_block & (ptrs - 1);
326 ext4_warning(inode->i_sb, "ext4_block_to_path",
327 "block %lu > max in inode %lu",
328 i_block + direct_blocks +
329 indirect_blocks + double_blocks, inode->i_ino);
332 *boundary = final - 1 - (i_block & (ptrs - 1));
336 static int __ext4_check_blockref(const char *function, struct inode *inode,
337 __le32 *p, unsigned int max)
342 while (bref < p+max) {
343 blk = le32_to_cpu(*bref++);
345 unlikely(!ext4_data_block_valid(EXT4_SB(inode->i_sb),
347 ext4_error(inode->i_sb, function,
348 "invalid block reference %u "
349 "in inode #%lu", blk, inode->i_ino);
357 #define ext4_check_indirect_blockref(inode, bh) \
358 __ext4_check_blockref(__func__, inode, (__le32 *)(bh)->b_data, \
359 EXT4_ADDR_PER_BLOCK((inode)->i_sb))
361 #define ext4_check_inode_blockref(inode) \
362 __ext4_check_blockref(__func__, inode, EXT4_I(inode)->i_data, \
366 * ext4_get_branch - read the chain of indirect blocks leading to data
367 * @inode: inode in question
368 * @depth: depth of the chain (1 - direct pointer, etc.)
369 * @offsets: offsets of pointers in inode/indirect blocks
370 * @chain: place to store the result
371 * @err: here we store the error value
373 * Function fills the array of triples <key, p, bh> and returns %NULL
374 * if everything went OK or the pointer to the last filled triple
375 * (incomplete one) otherwise. Upon the return chain[i].key contains
376 * the number of (i+1)-th block in the chain (as it is stored in memory,
377 * i.e. little-endian 32-bit), chain[i].p contains the address of that
378 * number (it points into struct inode for i==0 and into the bh->b_data
379 * for i>0) and chain[i].bh points to the buffer_head of i-th indirect
380 * block for i>0 and NULL for i==0. In other words, it holds the block
381 * numbers of the chain, addresses they were taken from (and where we can
382 * verify that chain did not change) and buffer_heads hosting these
385 * Function stops when it stumbles upon zero pointer (absent block)
386 * (pointer to last triple returned, *@err == 0)
387 * or when it gets an IO error reading an indirect block
388 * (ditto, *@err == -EIO)
389 * or when it reads all @depth-1 indirect blocks successfully and finds
390 * the whole chain, all way to the data (returns %NULL, *err == 0).
392 * Need to be called with
393 * down_read(&EXT4_I(inode)->i_data_sem)
395 static Indirect *ext4_get_branch(struct inode *inode, int depth,
396 ext4_lblk_t *offsets,
397 Indirect chain[4], int *err)
399 struct super_block *sb = inode->i_sb;
401 struct buffer_head *bh;
404 /* i_data is not going away, no lock needed */
405 add_chain(chain, NULL, EXT4_I(inode)->i_data + *offsets);
409 bh = sb_getblk(sb, le32_to_cpu(p->key));
413 if (!bh_uptodate_or_lock(bh)) {
414 if (bh_submit_read(bh) < 0) {
418 /* validate block references */
419 if (ext4_check_indirect_blockref(inode, bh)) {
425 add_chain(++p, bh, (__le32 *)bh->b_data + *++offsets);
439 * ext4_find_near - find a place for allocation with sufficient locality
441 * @ind: descriptor of indirect block.
443 * This function returns the preferred place for block allocation.
444 * It is used when heuristic for sequential allocation fails.
446 * + if there is a block to the left of our position - allocate near it.
447 * + if pointer will live in indirect block - allocate near that block.
448 * + if pointer will live in inode - allocate in the same
451 * In the latter case we colour the starting block by the callers PID to
452 * prevent it from clashing with concurrent allocations for a different inode
453 * in the same block group. The PID is used here so that functionally related
454 * files will be close-by on-disk.
456 * Caller must make sure that @ind is valid and will stay that way.
458 static ext4_fsblk_t ext4_find_near(struct inode *inode, Indirect *ind)
460 struct ext4_inode_info *ei = EXT4_I(inode);
461 __le32 *start = ind->bh ? (__le32 *) ind->bh->b_data : ei->i_data;
463 ext4_fsblk_t bg_start;
464 ext4_fsblk_t last_block;
465 ext4_grpblk_t colour;
466 ext4_group_t block_group;
467 int flex_size = ext4_flex_bg_size(EXT4_SB(inode->i_sb));
469 /* Try to find previous block */
470 for (p = ind->p - 1; p >= start; p--) {
472 return le32_to_cpu(*p);
475 /* No such thing, so let's try location of indirect block */
477 return ind->bh->b_blocknr;
480 * It is going to be referred to from the inode itself? OK, just put it
481 * into the same cylinder group then.
483 block_group = ei->i_block_group;
484 if (flex_size >= EXT4_FLEX_SIZE_DIR_ALLOC_SCHEME) {
485 block_group &= ~(flex_size-1);
486 if (S_ISREG(inode->i_mode))
489 bg_start = ext4_group_first_block_no(inode->i_sb, block_group);
490 last_block = ext4_blocks_count(EXT4_SB(inode->i_sb)->s_es) - 1;
493 * If we are doing delayed allocation, we don't need take
494 * colour into account.
496 if (test_opt(inode->i_sb, DELALLOC))
499 if (bg_start + EXT4_BLOCKS_PER_GROUP(inode->i_sb) <= last_block)
500 colour = (current->pid % 16) *
501 (EXT4_BLOCKS_PER_GROUP(inode->i_sb) / 16);
503 colour = (current->pid % 16) * ((last_block - bg_start) / 16);
504 return bg_start + colour;
508 * ext4_find_goal - find a preferred place for allocation.
510 * @block: block we want
511 * @partial: pointer to the last triple within a chain
513 * Normally this function find the preferred place for block allocation,
515 * Because this is only used for non-extent files, we limit the block nr
518 static ext4_fsblk_t ext4_find_goal(struct inode *inode, ext4_lblk_t block,
524 * XXX need to get goal block from mballoc's data structures
527 goal = ext4_find_near(inode, partial);
528 goal = goal & EXT4_MAX_BLOCK_FILE_PHYS;
533 * ext4_blks_to_allocate: Look up the block map and count the number
534 * of direct blocks need to be allocated for the given branch.
536 * @branch: chain of indirect blocks
537 * @k: number of blocks need for indirect blocks
538 * @blks: number of data blocks to be mapped.
539 * @blocks_to_boundary: the offset in the indirect block
541 * return the total number of blocks to be allocate, including the
542 * direct and indirect blocks.
544 static int ext4_blks_to_allocate(Indirect *branch, int k, unsigned int blks,
545 int blocks_to_boundary)
547 unsigned int count = 0;
550 * Simple case, [t,d]Indirect block(s) has not allocated yet
551 * then it's clear blocks on that path have not allocated
554 /* right now we don't handle cross boundary allocation */
555 if (blks < blocks_to_boundary + 1)
558 count += blocks_to_boundary + 1;
563 while (count < blks && count <= blocks_to_boundary &&
564 le32_to_cpu(*(branch[0].p + count)) == 0) {
571 * ext4_alloc_blocks: multiple allocate blocks needed for a branch
572 * @indirect_blks: the number of blocks need to allocate for indirect
575 * @new_blocks: on return it will store the new block numbers for
576 * the indirect blocks(if needed) and the first direct block,
577 * @blks: on return it will store the total number of allocated
580 static int ext4_alloc_blocks(handle_t *handle, struct inode *inode,
581 ext4_lblk_t iblock, ext4_fsblk_t goal,
582 int indirect_blks, int blks,
583 ext4_fsblk_t new_blocks[4], int *err)
585 struct ext4_allocation_request ar;
587 unsigned long count = 0, blk_allocated = 0;
589 ext4_fsblk_t current_block = 0;
593 * Here we try to allocate the requested multiple blocks at once,
594 * on a best-effort basis.
595 * To build a branch, we should allocate blocks for
596 * the indirect blocks(if not allocated yet), and at least
597 * the first direct block of this branch. That's the
598 * minimum number of blocks need to allocate(required)
600 /* first we try to allocate the indirect blocks */
601 target = indirect_blks;
604 /* allocating blocks for indirect blocks and direct blocks */
605 current_block = ext4_new_meta_blocks(handle, inode,
610 BUG_ON(current_block + count > EXT4_MAX_BLOCK_FILE_PHYS);
613 /* allocate blocks for indirect blocks */
614 while (index < indirect_blks && count) {
615 new_blocks[index++] = current_block++;
620 * save the new block number
621 * for the first direct block
623 new_blocks[index] = current_block;
624 printk(KERN_INFO "%s returned more blocks than "
625 "requested\n", __func__);
631 target = blks - count ;
632 blk_allocated = count;
635 /* Now allocate data blocks */
636 memset(&ar, 0, sizeof(ar));
641 if (S_ISREG(inode->i_mode))
642 /* enable in-core preallocation only for regular files */
643 ar.flags = EXT4_MB_HINT_DATA;
645 current_block = ext4_mb_new_blocks(handle, &ar, err);
646 BUG_ON(current_block + ar.len > EXT4_MAX_BLOCK_FILE_PHYS);
648 if (*err && (target == blks)) {
650 * if the allocation failed and we didn't allocate
656 if (target == blks) {
658 * save the new block number
659 * for the first direct block
661 new_blocks[index] = current_block;
663 blk_allocated += ar.len;
666 /* total number of blocks allocated for direct blocks */
671 for (i = 0; i < index; i++)
672 ext4_free_blocks(handle, inode, 0, new_blocks[i], 1, 0);
677 * ext4_alloc_branch - allocate and set up a chain of blocks.
679 * @indirect_blks: number of allocated indirect blocks
680 * @blks: number of allocated direct blocks
681 * @offsets: offsets (in the blocks) to store the pointers to next.
682 * @branch: place to store the chain in.
684 * This function allocates blocks, zeroes out all but the last one,
685 * links them into chain and (if we are synchronous) writes them to disk.
686 * In other words, it prepares a branch that can be spliced onto the
687 * inode. It stores the information about that chain in the branch[], in
688 * the same format as ext4_get_branch() would do. We are calling it after
689 * we had read the existing part of chain and partial points to the last
690 * triple of that (one with zero ->key). Upon the exit we have the same
691 * picture as after the successful ext4_get_block(), except that in one
692 * place chain is disconnected - *branch->p is still zero (we did not
693 * set the last link), but branch->key contains the number that should
694 * be placed into *branch->p to fill that gap.
696 * If allocation fails we free all blocks we've allocated (and forget
697 * their buffer_heads) and return the error value the from failed
698 * ext4_alloc_block() (normally -ENOSPC). Otherwise we set the chain
699 * as described above and return 0.
701 static int ext4_alloc_branch(handle_t *handle, struct inode *inode,
702 ext4_lblk_t iblock, int indirect_blks,
703 int *blks, ext4_fsblk_t goal,
704 ext4_lblk_t *offsets, Indirect *branch)
706 int blocksize = inode->i_sb->s_blocksize;
709 struct buffer_head *bh;
711 ext4_fsblk_t new_blocks[4];
712 ext4_fsblk_t current_block;
714 num = ext4_alloc_blocks(handle, inode, iblock, goal, indirect_blks,
715 *blks, new_blocks, &err);
719 branch[0].key = cpu_to_le32(new_blocks[0]);
721 * metadata blocks and data blocks are allocated.
723 for (n = 1; n <= indirect_blks; n++) {
725 * Get buffer_head for parent block, zero it out
726 * and set the pointer to new one, then send
729 bh = sb_getblk(inode->i_sb, new_blocks[n-1]);
732 BUFFER_TRACE(bh, "call get_create_access");
733 err = ext4_journal_get_create_access(handle, bh);
735 /* Don't brelse(bh) here; it's done in
736 * ext4_journal_forget() below */
741 memset(bh->b_data, 0, blocksize);
742 branch[n].p = (__le32 *) bh->b_data + offsets[n];
743 branch[n].key = cpu_to_le32(new_blocks[n]);
744 *branch[n].p = branch[n].key;
745 if (n == indirect_blks) {
746 current_block = new_blocks[n];
748 * End of chain, update the last new metablock of
749 * the chain to point to the new allocated
750 * data blocks numbers
752 for (i = 1; i < num; i++)
753 *(branch[n].p + i) = cpu_to_le32(++current_block);
755 BUFFER_TRACE(bh, "marking uptodate");
756 set_buffer_uptodate(bh);
759 BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
760 err = ext4_handle_dirty_metadata(handle, inode, bh);
767 /* Allocation failed, free what we already allocated */
768 ext4_free_blocks(handle, inode, 0, new_blocks[0], 1, 0);
769 for (i = 1; i <= n ; i++) {
771 * branch[i].bh is newly allocated, so there is no
772 * need to revoke the block, which is why we don't
773 * need to set EXT4_FREE_BLOCKS_METADATA.
775 ext4_free_blocks(handle, inode, 0, new_blocks[i], 1,
776 EXT4_FREE_BLOCKS_FORGET);
778 for (i = n+1; i < indirect_blks; i++)
779 ext4_free_blocks(handle, inode, 0, new_blocks[i], 1, 0);
781 ext4_free_blocks(handle, inode, 0, new_blocks[i], num, 0);
787 * ext4_splice_branch - splice the allocated branch onto inode.
789 * @block: (logical) number of block we are adding
790 * @chain: chain of indirect blocks (with a missing link - see
792 * @where: location of missing link
793 * @num: number of indirect blocks we are adding
794 * @blks: number of direct blocks we are adding
796 * This function fills the missing link and does all housekeeping needed in
797 * inode (->i_blocks, etc.). In case of success we end up with the full
798 * chain to new block and return 0.
800 static int ext4_splice_branch(handle_t *handle, struct inode *inode,
801 ext4_lblk_t block, Indirect *where, int num,
806 ext4_fsblk_t current_block;
809 * If we're splicing into a [td]indirect block (as opposed to the
810 * inode) then we need to get write access to the [td]indirect block
814 BUFFER_TRACE(where->bh, "get_write_access");
815 err = ext4_journal_get_write_access(handle, where->bh);
821 *where->p = where->key;
824 * Update the host buffer_head or inode to point to more just allocated
825 * direct blocks blocks
827 if (num == 0 && blks > 1) {
828 current_block = le32_to_cpu(where->key) + 1;
829 for (i = 1; i < blks; i++)
830 *(where->p + i) = cpu_to_le32(current_block++);
833 /* We are done with atomic stuff, now do the rest of housekeeping */
834 /* had we spliced it onto indirect block? */
837 * If we spliced it onto an indirect block, we haven't
838 * altered the inode. Note however that if it is being spliced
839 * onto an indirect block at the very end of the file (the
840 * file is growing) then we *will* alter the inode to reflect
841 * the new i_size. But that is not done here - it is done in
842 * generic_commit_write->__mark_inode_dirty->ext4_dirty_inode.
844 jbd_debug(5, "splicing indirect only\n");
845 BUFFER_TRACE(where->bh, "call ext4_handle_dirty_metadata");
846 err = ext4_handle_dirty_metadata(handle, inode, where->bh);
851 * OK, we spliced it into the inode itself on a direct block.
853 ext4_mark_inode_dirty(handle, inode);
854 jbd_debug(5, "splicing direct\n");
859 for (i = 1; i <= num; i++) {
861 * branch[i].bh is newly allocated, so there is no
862 * need to revoke the block, which is why we don't
863 * need to set EXT4_FREE_BLOCKS_METADATA.
865 ext4_free_blocks(handle, inode, where[i].bh, 0, 1,
866 EXT4_FREE_BLOCKS_FORGET);
868 ext4_free_blocks(handle, inode, 0, le32_to_cpu(where[num].key),
875 * The ext4_ind_get_blocks() function handles non-extents inodes
876 * (i.e., using the traditional indirect/double-indirect i_blocks
877 * scheme) for ext4_get_blocks().
879 * Allocation strategy is simple: if we have to allocate something, we will
880 * have to go the whole way to leaf. So let's do it before attaching anything
881 * to tree, set linkage between the newborn blocks, write them if sync is
882 * required, recheck the path, free and repeat if check fails, otherwise
883 * set the last missing link (that will protect us from any truncate-generated
884 * removals - all blocks on the path are immune now) and possibly force the
885 * write on the parent block.
886 * That has a nice additional property: no special recovery from the failed
887 * allocations is needed - we simply release blocks and do not touch anything
888 * reachable from inode.
890 * `handle' can be NULL if create == 0.
892 * return > 0, # of blocks mapped or allocated.
893 * return = 0, if plain lookup failed.
894 * return < 0, error case.
896 * The ext4_ind_get_blocks() function should be called with
897 * down_write(&EXT4_I(inode)->i_data_sem) if allocating filesystem
898 * blocks (i.e., flags has EXT4_GET_BLOCKS_CREATE set) or
899 * down_read(&EXT4_I(inode)->i_data_sem) if not allocating file system
902 static int ext4_ind_get_blocks(handle_t *handle, struct inode *inode,
903 ext4_lblk_t iblock, unsigned int maxblocks,
904 struct buffer_head *bh_result,
908 ext4_lblk_t offsets[4];
913 int blocks_to_boundary = 0;
916 ext4_fsblk_t first_block = 0;
918 J_ASSERT(!(EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL));
919 J_ASSERT(handle != NULL || (flags & EXT4_GET_BLOCKS_CREATE) == 0);
920 depth = ext4_block_to_path(inode, iblock, offsets,
921 &blocks_to_boundary);
926 partial = ext4_get_branch(inode, depth, offsets, chain, &err);
928 /* Simplest case - block found, no allocation needed */
930 first_block = le32_to_cpu(chain[depth - 1].key);
931 clear_buffer_new(bh_result);
934 while (count < maxblocks && count <= blocks_to_boundary) {
937 blk = le32_to_cpu(*(chain[depth-1].p + count));
939 if (blk == first_block + count)
947 /* Next simple case - plain lookup or failed read of indirect block */
948 if ((flags & EXT4_GET_BLOCKS_CREATE) == 0 || err == -EIO)
952 * Okay, we need to do block allocation.
954 goal = ext4_find_goal(inode, iblock, partial);
956 /* the number of blocks need to allocate for [d,t]indirect blocks */
957 indirect_blks = (chain + depth) - partial - 1;
960 * Next look up the indirect map to count the totoal number of
961 * direct blocks to allocate for this branch.
963 count = ext4_blks_to_allocate(partial, indirect_blks,
964 maxblocks, blocks_to_boundary);
966 * Block out ext4_truncate while we alter the tree
968 err = ext4_alloc_branch(handle, inode, iblock, indirect_blks,
970 offsets + (partial - chain), partial);
973 * The ext4_splice_branch call will free and forget any buffers
974 * on the new chain if there is a failure, but that risks using
975 * up transaction credits, especially for bitmaps where the
976 * credits cannot be returned. Can we handle this somehow? We
977 * may need to return -EAGAIN upwards in the worst case. --sct
980 err = ext4_splice_branch(handle, inode, iblock,
981 partial, indirect_blks, count);
985 set_buffer_new(bh_result);
987 map_bh(bh_result, inode->i_sb, le32_to_cpu(chain[depth-1].key));
988 if (count > blocks_to_boundary)
989 set_buffer_boundary(bh_result);
991 /* Clean up and exit */
992 partial = chain + depth - 1; /* the whole chain */
994 while (partial > chain) {
995 BUFFER_TRACE(partial->bh, "call brelse");
999 BUFFER_TRACE(bh_result, "returned");
1004 qsize_t ext4_get_reserved_space(struct inode *inode)
1006 unsigned long long total;
1008 spin_lock(&EXT4_I(inode)->i_block_reservation_lock);
1009 total = EXT4_I(inode)->i_reserved_data_blocks +
1010 EXT4_I(inode)->i_reserved_meta_blocks;
1011 spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
1016 * Calculate the number of metadata blocks need to reserve
1017 * to allocate @blocks for non extent file based file
1019 static int ext4_indirect_calc_metadata_amount(struct inode *inode, int blocks)
1021 int icap = EXT4_ADDR_PER_BLOCK(inode->i_sb);
1022 int ind_blks, dind_blks, tind_blks;
1024 /* number of new indirect blocks needed */
1025 ind_blks = (blocks + icap - 1) / icap;
1027 dind_blks = (ind_blks + icap - 1) / icap;
1031 return ind_blks + dind_blks + tind_blks;
1035 * Calculate the number of metadata blocks need to reserve
1036 * to allocate given number of blocks
1038 static int ext4_calc_metadata_amount(struct inode *inode, int blocks)
1043 if (EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL)
1044 return ext4_ext_calc_metadata_amount(inode, blocks);
1046 return ext4_indirect_calc_metadata_amount(inode, blocks);
1049 static void ext4_da_update_reserve_space(struct inode *inode, int used)
1051 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
1052 int total, mdb, mdb_free;
1054 spin_lock(&EXT4_I(inode)->i_block_reservation_lock);
1055 /* recalculate the number of metablocks still need to be reserved */
1056 total = EXT4_I(inode)->i_reserved_data_blocks - used;
1057 mdb = ext4_calc_metadata_amount(inode, total);
1059 /* figure out how many metablocks to release */
1060 BUG_ON(mdb > EXT4_I(inode)->i_reserved_meta_blocks);
1061 mdb_free = EXT4_I(inode)->i_reserved_meta_blocks - mdb;
1064 /* Account for allocated meta_blocks */
1065 mdb_free -= EXT4_I(inode)->i_allocated_meta_blocks;
1067 /* update fs dirty blocks counter */
1068 percpu_counter_sub(&sbi->s_dirtyblocks_counter, mdb_free);
1069 EXT4_I(inode)->i_allocated_meta_blocks = 0;
1070 EXT4_I(inode)->i_reserved_meta_blocks = mdb;
1073 /* update per-inode reservations */
1074 BUG_ON(used > EXT4_I(inode)->i_reserved_data_blocks);
1075 EXT4_I(inode)->i_reserved_data_blocks -= used;
1076 spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
1079 * free those over-booking quota for metadata blocks
1082 vfs_dq_release_reservation_block(inode, mdb_free);
1085 * If we have done all the pending block allocations and if
1086 * there aren't any writers on the inode, we can discard the
1087 * inode's preallocations.
1089 if (!total && (atomic_read(&inode->i_writecount) == 0))
1090 ext4_discard_preallocations(inode);
1093 static int check_block_validity(struct inode *inode, const char *msg,
1094 sector_t logical, sector_t phys, int len)
1096 if (!ext4_data_block_valid(EXT4_SB(inode->i_sb), phys, len)) {
1097 ext4_error(inode->i_sb, msg,
1098 "inode #%lu logical block %llu mapped to %llu "
1099 "(size %d)", inode->i_ino,
1100 (unsigned long long) logical,
1101 (unsigned long long) phys, len);
1108 * Return the number of contiguous dirty pages in a given inode
1109 * starting at page frame idx.
1111 static pgoff_t ext4_num_dirty_pages(struct inode *inode, pgoff_t idx,
1112 unsigned int max_pages)
1114 struct address_space *mapping = inode->i_mapping;
1116 struct pagevec pvec;
1118 int i, nr_pages, done = 0;
1122 pagevec_init(&pvec, 0);
1125 nr_pages = pagevec_lookup_tag(&pvec, mapping, &index,
1126 PAGECACHE_TAG_DIRTY,
1127 (pgoff_t)PAGEVEC_SIZE);
1130 for (i = 0; i < nr_pages; i++) {
1131 struct page *page = pvec.pages[i];
1132 struct buffer_head *bh, *head;
1135 if (unlikely(page->mapping != mapping) ||
1137 PageWriteback(page) ||
1138 page->index != idx) {
1143 if (page_has_buffers(page)) {
1144 bh = head = page_buffers(page);
1146 if (!buffer_delay(bh) &&
1147 !buffer_unwritten(bh))
1149 bh = bh->b_this_page;
1150 } while (!done && (bh != head));
1157 if (num >= max_pages)
1160 pagevec_release(&pvec);
1166 * The ext4_get_blocks() function tries to look up the requested blocks,
1167 * and returns if the blocks are already mapped.
1169 * Otherwise it takes the write lock of the i_data_sem and allocate blocks
1170 * and store the allocated blocks in the result buffer head and mark it
1173 * If file type is extents based, it will call ext4_ext_get_blocks(),
1174 * Otherwise, call with ext4_ind_get_blocks() to handle indirect mapping
1177 * On success, it returns the number of blocks being mapped or allocate.
1178 * if create==0 and the blocks are pre-allocated and uninitialized block,
1179 * the result buffer head is unmapped. If the create ==1, it will make sure
1180 * the buffer head is mapped.
1182 * It returns 0 if plain look up failed (blocks have not been allocated), in
1183 * that casem, buffer head is unmapped
1185 * It returns the error in case of allocation failure.
1187 int ext4_get_blocks(handle_t *handle, struct inode *inode, sector_t block,
1188 unsigned int max_blocks, struct buffer_head *bh,
1193 clear_buffer_mapped(bh);
1194 clear_buffer_unwritten(bh);
1196 ext_debug("ext4_get_blocks(): inode %lu, flag %d, max_blocks %u,"
1197 "logical block %lu\n", inode->i_ino, flags, max_blocks,
1198 (unsigned long)block);
1200 * Try to see if we can get the block without requesting a new
1201 * file system block.
1203 down_read((&EXT4_I(inode)->i_data_sem));
1204 if (EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL) {
1205 retval = ext4_ext_get_blocks(handle, inode, block, max_blocks,
1208 retval = ext4_ind_get_blocks(handle, inode, block, max_blocks,
1211 up_read((&EXT4_I(inode)->i_data_sem));
1213 if (retval > 0 && buffer_mapped(bh)) {
1214 int ret = check_block_validity(inode, "file system corruption",
1215 block, bh->b_blocknr, retval);
1220 /* If it is only a block(s) look up */
1221 if ((flags & EXT4_GET_BLOCKS_CREATE) == 0)
1225 * Returns if the blocks have already allocated
1227 * Note that if blocks have been preallocated
1228 * ext4_ext_get_block() returns th create = 0
1229 * with buffer head unmapped.
1231 if (retval > 0 && buffer_mapped(bh))
1235 * When we call get_blocks without the create flag, the
1236 * BH_Unwritten flag could have gotten set if the blocks
1237 * requested were part of a uninitialized extent. We need to
1238 * clear this flag now that we are committed to convert all or
1239 * part of the uninitialized extent to be an initialized
1240 * extent. This is because we need to avoid the combination
1241 * of BH_Unwritten and BH_Mapped flags being simultaneously
1242 * set on the buffer_head.
1244 clear_buffer_unwritten(bh);
1247 * New blocks allocate and/or writing to uninitialized extent
1248 * will possibly result in updating i_data, so we take
1249 * the write lock of i_data_sem, and call get_blocks()
1250 * with create == 1 flag.
1252 down_write((&EXT4_I(inode)->i_data_sem));
1255 * if the caller is from delayed allocation writeout path
1256 * we have already reserved fs blocks for allocation
1257 * let the underlying get_block() function know to
1258 * avoid double accounting
1260 if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE)
1261 EXT4_I(inode)->i_delalloc_reserved_flag = 1;
1263 * We need to check for EXT4 here because migrate
1264 * could have changed the inode type in between
1266 if (EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL) {
1267 retval = ext4_ext_get_blocks(handle, inode, block, max_blocks,
1270 retval = ext4_ind_get_blocks(handle, inode, block,
1271 max_blocks, bh, flags);
1273 if (retval > 0 && buffer_new(bh)) {
1275 * We allocated new blocks which will result in
1276 * i_data's format changing. Force the migrate
1277 * to fail by clearing migrate flags
1279 EXT4_I(inode)->i_state &= ~EXT4_STATE_EXT_MIGRATE;
1283 if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE)
1284 EXT4_I(inode)->i_delalloc_reserved_flag = 0;
1287 * Update reserved blocks/metadata blocks after successful
1288 * block allocation which had been deferred till now.
1290 if ((retval > 0) && (flags & EXT4_GET_BLOCKS_UPDATE_RESERVE_SPACE))
1291 ext4_da_update_reserve_space(inode, retval);
1293 up_write((&EXT4_I(inode)->i_data_sem));
1294 if (retval > 0 && buffer_mapped(bh)) {
1295 int ret = check_block_validity(inode, "file system "
1296 "corruption after allocation",
1297 block, bh->b_blocknr, retval);
1304 /* Maximum number of blocks we map for direct IO at once. */
1305 #define DIO_MAX_BLOCKS 4096
1307 int ext4_get_block(struct inode *inode, sector_t iblock,
1308 struct buffer_head *bh_result, int create)
1310 handle_t *handle = ext4_journal_current_handle();
1311 int ret = 0, started = 0;
1312 unsigned max_blocks = bh_result->b_size >> inode->i_blkbits;
1315 if (create && !handle) {
1316 /* Direct IO write... */
1317 if (max_blocks > DIO_MAX_BLOCKS)
1318 max_blocks = DIO_MAX_BLOCKS;
1319 dio_credits = ext4_chunk_trans_blocks(inode, max_blocks);
1320 handle = ext4_journal_start(inode, dio_credits);
1321 if (IS_ERR(handle)) {
1322 ret = PTR_ERR(handle);
1328 ret = ext4_get_blocks(handle, inode, iblock, max_blocks, bh_result,
1329 create ? EXT4_GET_BLOCKS_CREATE : 0);
1331 bh_result->b_size = (ret << inode->i_blkbits);
1335 ext4_journal_stop(handle);
1341 * `handle' can be NULL if create is zero
1343 struct buffer_head *ext4_getblk(handle_t *handle, struct inode *inode,
1344 ext4_lblk_t block, int create, int *errp)
1346 struct buffer_head dummy;
1350 J_ASSERT(handle != NULL || create == 0);
1353 dummy.b_blocknr = -1000;
1354 buffer_trace_init(&dummy.b_history);
1356 flags |= EXT4_GET_BLOCKS_CREATE;
1357 err = ext4_get_blocks(handle, inode, block, 1, &dummy, flags);
1359 * ext4_get_blocks() returns number of blocks mapped. 0 in
1368 if (!err && buffer_mapped(&dummy)) {
1369 struct buffer_head *bh;
1370 bh = sb_getblk(inode->i_sb, dummy.b_blocknr);
1375 if (buffer_new(&dummy)) {
1376 J_ASSERT(create != 0);
1377 J_ASSERT(handle != NULL);
1380 * Now that we do not always journal data, we should
1381 * keep in mind whether this should always journal the
1382 * new buffer as metadata. For now, regular file
1383 * writes use ext4_get_block instead, so it's not a
1387 BUFFER_TRACE(bh, "call get_create_access");
1388 fatal = ext4_journal_get_create_access(handle, bh);
1389 if (!fatal && !buffer_uptodate(bh)) {
1390 memset(bh->b_data, 0, inode->i_sb->s_blocksize);
1391 set_buffer_uptodate(bh);
1394 BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
1395 err = ext4_handle_dirty_metadata(handle, inode, bh);
1399 BUFFER_TRACE(bh, "not a new buffer");
1412 struct buffer_head *ext4_bread(handle_t *handle, struct inode *inode,
1413 ext4_lblk_t block, int create, int *err)
1415 struct buffer_head *bh;
1417 bh = ext4_getblk(handle, inode, block, create, err);
1420 if (buffer_uptodate(bh))
1422 ll_rw_block(READ_META, 1, &bh);
1424 if (buffer_uptodate(bh))
1431 static int walk_page_buffers(handle_t *handle,
1432 struct buffer_head *head,
1436 int (*fn)(handle_t *handle,
1437 struct buffer_head *bh))
1439 struct buffer_head *bh;
1440 unsigned block_start, block_end;
1441 unsigned blocksize = head->b_size;
1443 struct buffer_head *next;
1445 for (bh = head, block_start = 0;
1446 ret == 0 && (bh != head || !block_start);
1447 block_start = block_end, bh = next) {
1448 next = bh->b_this_page;
1449 block_end = block_start + blocksize;
1450 if (block_end <= from || block_start >= to) {
1451 if (partial && !buffer_uptodate(bh))
1455 err = (*fn)(handle, bh);
1463 * To preserve ordering, it is essential that the hole instantiation and
1464 * the data write be encapsulated in a single transaction. We cannot
1465 * close off a transaction and start a new one between the ext4_get_block()
1466 * and the commit_write(). So doing the jbd2_journal_start at the start of
1467 * prepare_write() is the right place.
1469 * Also, this function can nest inside ext4_writepage() ->
1470 * block_write_full_page(). In that case, we *know* that ext4_writepage()
1471 * has generated enough buffer credits to do the whole page. So we won't
1472 * block on the journal in that case, which is good, because the caller may
1475 * By accident, ext4 can be reentered when a transaction is open via
1476 * quota file writes. If we were to commit the transaction while thus
1477 * reentered, there can be a deadlock - we would be holding a quota
1478 * lock, and the commit would never complete if another thread had a
1479 * transaction open and was blocking on the quota lock - a ranking
1482 * So what we do is to rely on the fact that jbd2_journal_stop/journal_start
1483 * will _not_ run commit under these circumstances because handle->h_ref
1484 * is elevated. We'll still have enough credits for the tiny quotafile
1487 static int do_journal_get_write_access(handle_t *handle,
1488 struct buffer_head *bh)
1490 if (!buffer_mapped(bh) || buffer_freed(bh))
1492 return ext4_journal_get_write_access(handle, bh);
1495 static int ext4_write_begin(struct file *file, struct address_space *mapping,
1496 loff_t pos, unsigned len, unsigned flags,
1497 struct page **pagep, void **fsdata)
1499 struct inode *inode = mapping->host;
1500 int ret, needed_blocks;
1507 trace_ext4_write_begin(inode, pos, len, flags);
1509 * Reserve one block more for addition to orphan list in case
1510 * we allocate blocks but write fails for some reason
1512 needed_blocks = ext4_writepage_trans_blocks(inode) + 1;
1513 index = pos >> PAGE_CACHE_SHIFT;
1514 from = pos & (PAGE_CACHE_SIZE - 1);
1518 handle = ext4_journal_start(inode, needed_blocks);
1519 if (IS_ERR(handle)) {
1520 ret = PTR_ERR(handle);
1524 /* We cannot recurse into the filesystem as the transaction is already
1526 flags |= AOP_FLAG_NOFS;
1528 page = grab_cache_page_write_begin(mapping, index, flags);
1530 ext4_journal_stop(handle);
1536 ret = block_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
1539 if (!ret && ext4_should_journal_data(inode)) {
1540 ret = walk_page_buffers(handle, page_buffers(page),
1541 from, to, NULL, do_journal_get_write_access);
1546 page_cache_release(page);
1548 * block_write_begin may have instantiated a few blocks
1549 * outside i_size. Trim these off again. Don't need
1550 * i_size_read because we hold i_mutex.
1552 * Add inode to orphan list in case we crash before
1555 if (pos + len > inode->i_size && ext4_can_truncate(inode))
1556 ext4_orphan_add(handle, inode);
1558 ext4_journal_stop(handle);
1559 if (pos + len > inode->i_size) {
1560 ext4_truncate(inode);
1562 * If truncate failed early the inode might
1563 * still be on the orphan list; we need to
1564 * make sure the inode is removed from the
1565 * orphan list in that case.
1568 ext4_orphan_del(NULL, inode);
1572 if (ret == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
1578 /* For write_end() in data=journal mode */
1579 static int write_end_fn(handle_t *handle, struct buffer_head *bh)
1581 if (!buffer_mapped(bh) || buffer_freed(bh))
1583 set_buffer_uptodate(bh);
1584 return ext4_handle_dirty_metadata(handle, NULL, bh);
1587 static int ext4_generic_write_end(struct file *file,
1588 struct address_space *mapping,
1589 loff_t pos, unsigned len, unsigned copied,
1590 struct page *page, void *fsdata)
1592 int i_size_changed = 0;
1593 struct inode *inode = mapping->host;
1594 handle_t *handle = ext4_journal_current_handle();
1596 copied = block_write_end(file, mapping, pos, len, copied, page, fsdata);
1599 * No need to use i_size_read() here, the i_size
1600 * cannot change under us because we hold i_mutex.
1602 * But it's important to update i_size while still holding page lock:
1603 * page writeout could otherwise come in and zero beyond i_size.
1605 if (pos + copied > inode->i_size) {
1606 i_size_write(inode, pos + copied);
1610 if (pos + copied > EXT4_I(inode)->i_disksize) {
1611 /* We need to mark inode dirty even if
1612 * new_i_size is less that inode->i_size
1613 * bu greater than i_disksize.(hint delalloc)
1615 ext4_update_i_disksize(inode, (pos + copied));
1619 page_cache_release(page);
1622 * Don't mark the inode dirty under page lock. First, it unnecessarily
1623 * makes the holding time of page lock longer. Second, it forces lock
1624 * ordering of page lock and transaction start for journaling
1628 ext4_mark_inode_dirty(handle, inode);
1634 * We need to pick up the new inode size which generic_commit_write gave us
1635 * `file' can be NULL - eg, when called from page_symlink().
1637 * ext4 never places buffers on inode->i_mapping->private_list. metadata
1638 * buffers are managed internally.
1640 static int ext4_ordered_write_end(struct file *file,
1641 struct address_space *mapping,
1642 loff_t pos, unsigned len, unsigned copied,
1643 struct page *page, void *fsdata)
1645 handle_t *handle = ext4_journal_current_handle();
1646 struct inode *inode = mapping->host;
1649 trace_ext4_ordered_write_end(inode, pos, len, copied);
1650 ret = ext4_jbd2_file_inode(handle, inode);
1653 ret2 = ext4_generic_write_end(file, mapping, pos, len, copied,
1656 if (pos + len > inode->i_size && ext4_can_truncate(inode))
1657 /* if we have allocated more blocks and copied
1658 * less. We will have blocks allocated outside
1659 * inode->i_size. So truncate them
1661 ext4_orphan_add(handle, inode);
1665 ret2 = ext4_journal_stop(handle);
1669 if (pos + len > inode->i_size) {
1670 ext4_truncate(inode);
1672 * If truncate failed early the inode might still be
1673 * on the orphan list; we need to make sure the inode
1674 * is removed from the orphan list in that case.
1677 ext4_orphan_del(NULL, inode);
1681 return ret ? ret : copied;
1684 static int ext4_writeback_write_end(struct file *file,
1685 struct address_space *mapping,
1686 loff_t pos, unsigned len, unsigned copied,
1687 struct page *page, void *fsdata)
1689 handle_t *handle = ext4_journal_current_handle();
1690 struct inode *inode = mapping->host;
1693 trace_ext4_writeback_write_end(inode, pos, len, copied);
1694 ret2 = ext4_generic_write_end(file, mapping, pos, len, copied,
1697 if (pos + len > inode->i_size && ext4_can_truncate(inode))
1698 /* if we have allocated more blocks and copied
1699 * less. We will have blocks allocated outside
1700 * inode->i_size. So truncate them
1702 ext4_orphan_add(handle, inode);
1707 ret2 = ext4_journal_stop(handle);
1711 if (pos + len > inode->i_size) {
1712 ext4_truncate(inode);
1714 * If truncate failed early the inode might still be
1715 * on the orphan list; we need to make sure the inode
1716 * is removed from the orphan list in that case.
1719 ext4_orphan_del(NULL, inode);
1722 return ret ? ret : copied;
1725 static int ext4_journalled_write_end(struct file *file,
1726 struct address_space *mapping,
1727 loff_t pos, unsigned len, unsigned copied,
1728 struct page *page, void *fsdata)
1730 handle_t *handle = ext4_journal_current_handle();
1731 struct inode *inode = mapping->host;
1737 trace_ext4_journalled_write_end(inode, pos, len, copied);
1738 from = pos & (PAGE_CACHE_SIZE - 1);
1742 if (!PageUptodate(page))
1744 page_zero_new_buffers(page, from+copied, to);
1747 ret = walk_page_buffers(handle, page_buffers(page), from,
1748 to, &partial, write_end_fn);
1750 SetPageUptodate(page);
1751 new_i_size = pos + copied;
1752 if (new_i_size > inode->i_size)
1753 i_size_write(inode, pos+copied);
1754 EXT4_I(inode)->i_state |= EXT4_STATE_JDATA;
1755 if (new_i_size > EXT4_I(inode)->i_disksize) {
1756 ext4_update_i_disksize(inode, new_i_size);
1757 ret2 = ext4_mark_inode_dirty(handle, inode);
1763 page_cache_release(page);
1764 if (pos + len > inode->i_size && ext4_can_truncate(inode))
1765 /* if we have allocated more blocks and copied
1766 * less. We will have blocks allocated outside
1767 * inode->i_size. So truncate them
1769 ext4_orphan_add(handle, inode);
1771 ret2 = ext4_journal_stop(handle);
1774 if (pos + len > inode->i_size) {
1775 ext4_truncate(inode);
1777 * If truncate failed early the inode might still be
1778 * on the orphan list; we need to make sure the inode
1779 * is removed from the orphan list in that case.
1782 ext4_orphan_del(NULL, inode);
1785 return ret ? ret : copied;
1788 static int ext4_da_reserve_space(struct inode *inode, int nrblocks)
1791 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
1792 unsigned long md_needed, mdblocks, total = 0;
1795 * recalculate the amount of metadata blocks to reserve
1796 * in order to allocate nrblocks
1797 * worse case is one extent per block
1800 spin_lock(&EXT4_I(inode)->i_block_reservation_lock);
1801 total = EXT4_I(inode)->i_reserved_data_blocks + nrblocks;
1802 mdblocks = ext4_calc_metadata_amount(inode, total);
1803 BUG_ON(mdblocks < EXT4_I(inode)->i_reserved_meta_blocks);
1805 md_needed = mdblocks - EXT4_I(inode)->i_reserved_meta_blocks;
1806 total = md_needed + nrblocks;
1809 * Make quota reservation here to prevent quota overflow
1810 * later. Real quota accounting is done at pages writeout
1813 if (vfs_dq_reserve_block(inode, total)) {
1814 spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
1818 if (ext4_claim_free_blocks(sbi, total)) {
1819 spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
1820 vfs_dq_release_reservation_block(inode, total);
1821 if (ext4_should_retry_alloc(inode->i_sb, &retries)) {
1827 EXT4_I(inode)->i_reserved_data_blocks += nrblocks;
1828 EXT4_I(inode)->i_reserved_meta_blocks = mdblocks;
1830 spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
1831 return 0; /* success */
1834 static void ext4_da_release_space(struct inode *inode, int to_free)
1836 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
1837 int total, mdb, mdb_free, release;
1840 return; /* Nothing to release, exit */
1842 spin_lock(&EXT4_I(inode)->i_block_reservation_lock);
1844 if (!EXT4_I(inode)->i_reserved_data_blocks) {
1846 * if there is no reserved blocks, but we try to free some
1847 * then the counter is messed up somewhere.
1848 * but since this function is called from invalidate
1849 * page, it's harmless to return without any action
1851 printk(KERN_INFO "ext4 delalloc try to release %d reserved "
1852 "blocks for inode %lu, but there is no reserved "
1853 "data blocks\n", to_free, inode->i_ino);
1854 spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
1858 /* recalculate the number of metablocks still need to be reserved */
1859 total = EXT4_I(inode)->i_reserved_data_blocks - to_free;
1860 mdb = ext4_calc_metadata_amount(inode, total);
1862 /* figure out how many metablocks to release */
1863 BUG_ON(mdb > EXT4_I(inode)->i_reserved_meta_blocks);
1864 mdb_free = EXT4_I(inode)->i_reserved_meta_blocks - mdb;
1866 release = to_free + mdb_free;
1868 /* update fs dirty blocks counter for truncate case */
1869 percpu_counter_sub(&sbi->s_dirtyblocks_counter, release);
1871 /* update per-inode reservations */
1872 BUG_ON(to_free > EXT4_I(inode)->i_reserved_data_blocks);
1873 EXT4_I(inode)->i_reserved_data_blocks -= to_free;
1875 BUG_ON(mdb > EXT4_I(inode)->i_reserved_meta_blocks);
1876 EXT4_I(inode)->i_reserved_meta_blocks = mdb;
1877 spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
1879 vfs_dq_release_reservation_block(inode, release);
1882 static void ext4_da_page_release_reservation(struct page *page,
1883 unsigned long offset)
1886 struct buffer_head *head, *bh;
1887 unsigned int curr_off = 0;
1889 head = page_buffers(page);
1892 unsigned int next_off = curr_off + bh->b_size;
1894 if ((offset <= curr_off) && (buffer_delay(bh))) {
1896 clear_buffer_delay(bh);
1898 curr_off = next_off;
1899 } while ((bh = bh->b_this_page) != head);
1900 ext4_da_release_space(page->mapping->host, to_release);
1904 * Delayed allocation stuff
1908 * mpage_da_submit_io - walks through extent of pages and try to write
1909 * them with writepage() call back
1911 * @mpd->inode: inode
1912 * @mpd->first_page: first page of the extent
1913 * @mpd->next_page: page after the last page of the extent
1915 * By the time mpage_da_submit_io() is called we expect all blocks
1916 * to be allocated. this may be wrong if allocation failed.
1918 * As pages are already locked by write_cache_pages(), we can't use it
1920 static int mpage_da_submit_io(struct mpage_da_data *mpd)
1923 struct pagevec pvec;
1924 unsigned long index, end;
1925 int ret = 0, err, nr_pages, i;
1926 struct inode *inode = mpd->inode;
1927 struct address_space *mapping = inode->i_mapping;
1929 BUG_ON(mpd->next_page <= mpd->first_page);
1931 * We need to start from the first_page to the next_page - 1
1932 * to make sure we also write the mapped dirty buffer_heads.
1933 * If we look at mpd->b_blocknr we would only be looking
1934 * at the currently mapped buffer_heads.
1936 index = mpd->first_page;
1937 end = mpd->next_page - 1;
1939 pagevec_init(&pvec, 0);
1940 while (index <= end) {
1941 nr_pages = pagevec_lookup(&pvec, mapping, index, PAGEVEC_SIZE);
1944 for (i = 0; i < nr_pages; i++) {
1945 struct page *page = pvec.pages[i];
1947 index = page->index;
1952 BUG_ON(!PageLocked(page));
1953 BUG_ON(PageWriteback(page));
1955 pages_skipped = mpd->wbc->pages_skipped;
1956 err = mapping->a_ops->writepage(page, mpd->wbc);
1957 if (!err && (pages_skipped == mpd->wbc->pages_skipped))
1959 * have successfully written the page
1960 * without skipping the same
1962 mpd->pages_written++;
1964 * In error case, we have to continue because
1965 * remaining pages are still locked
1966 * XXX: unlock and re-dirty them?
1971 pagevec_release(&pvec);
1977 * mpage_put_bnr_to_bhs - walk blocks and assign them actual numbers
1979 * @mpd->inode - inode to walk through
1980 * @exbh->b_blocknr - first block on a disk
1981 * @exbh->b_size - amount of space in bytes
1982 * @logical - first logical block to start assignment with
1984 * the function goes through all passed space and put actual disk
1985 * block numbers into buffer heads, dropping BH_Delay and BH_Unwritten
1987 static void mpage_put_bnr_to_bhs(struct mpage_da_data *mpd, sector_t logical,
1988 struct buffer_head *exbh)
1990 struct inode *inode = mpd->inode;
1991 struct address_space *mapping = inode->i_mapping;
1992 int blocks = exbh->b_size >> inode->i_blkbits;
1993 sector_t pblock = exbh->b_blocknr, cur_logical;
1994 struct buffer_head *head, *bh;
1996 struct pagevec pvec;
1999 index = logical >> (PAGE_CACHE_SHIFT - inode->i_blkbits);
2000 end = (logical + blocks - 1) >> (PAGE_CACHE_SHIFT - inode->i_blkbits);
2001 cur_logical = index << (PAGE_CACHE_SHIFT - inode->i_blkbits);
2003 pagevec_init(&pvec, 0);
2005 while (index <= end) {
2006 /* XXX: optimize tail */
2007 nr_pages = pagevec_lookup(&pvec, mapping, index, PAGEVEC_SIZE);
2010 for (i = 0; i < nr_pages; i++) {
2011 struct page *page = pvec.pages[i];
2013 index = page->index;
2018 BUG_ON(!PageLocked(page));
2019 BUG_ON(PageWriteback(page));
2020 BUG_ON(!page_has_buffers(page));
2022 bh = page_buffers(page);
2025 /* skip blocks out of the range */
2027 if (cur_logical >= logical)
2030 } while ((bh = bh->b_this_page) != head);
2033 if (cur_logical >= logical + blocks)
2036 if (buffer_delay(bh) ||
2037 buffer_unwritten(bh)) {
2039 BUG_ON(bh->b_bdev != inode->i_sb->s_bdev);
2041 if (buffer_delay(bh)) {
2042 clear_buffer_delay(bh);
2043 bh->b_blocknr = pblock;
2046 * unwritten already should have
2047 * blocknr assigned. Verify that
2049 clear_buffer_unwritten(bh);
2050 BUG_ON(bh->b_blocknr != pblock);
2053 } else if (buffer_mapped(bh))
2054 BUG_ON(bh->b_blocknr != pblock);
2058 } while ((bh = bh->b_this_page) != head);
2060 pagevec_release(&pvec);
2066 * __unmap_underlying_blocks - just a helper function to unmap
2067 * set of blocks described by @bh
2069 static inline void __unmap_underlying_blocks(struct inode *inode,
2070 struct buffer_head *bh)
2072 struct block_device *bdev = inode->i_sb->s_bdev;
2075 blocks = bh->b_size >> inode->i_blkbits;
2076 for (i = 0; i < blocks; i++)
2077 unmap_underlying_metadata(bdev, bh->b_blocknr + i);
2080 static void ext4_da_block_invalidatepages(struct mpage_da_data *mpd,
2081 sector_t logical, long blk_cnt)
2085 struct pagevec pvec;
2086 struct inode *inode = mpd->inode;
2087 struct address_space *mapping = inode->i_mapping;
2089 index = logical >> (PAGE_CACHE_SHIFT - inode->i_blkbits);
2090 end = (logical + blk_cnt - 1) >>
2091 (PAGE_CACHE_SHIFT - inode->i_blkbits);
2092 while (index <= end) {
2093 nr_pages = pagevec_lookup(&pvec, mapping, index, PAGEVEC_SIZE);
2096 for (i = 0; i < nr_pages; i++) {
2097 struct page *page = pvec.pages[i];
2098 index = page->index;
2103 BUG_ON(!PageLocked(page));
2104 BUG_ON(PageWriteback(page));
2105 block_invalidatepage(page, 0);
2106 ClearPageUptodate(page);
2113 static void ext4_print_free_blocks(struct inode *inode)
2115 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2116 printk(KERN_CRIT "Total free blocks count %lld\n",
2117 ext4_count_free_blocks(inode->i_sb));
2118 printk(KERN_CRIT "Free/Dirty block details\n");
2119 printk(KERN_CRIT "free_blocks=%lld\n",
2120 (long long) percpu_counter_sum(&sbi->s_freeblocks_counter));
2121 printk(KERN_CRIT "dirty_blocks=%lld\n",
2122 (long long) percpu_counter_sum(&sbi->s_dirtyblocks_counter));
2123 printk(KERN_CRIT "Block reservation details\n");
2124 printk(KERN_CRIT "i_reserved_data_blocks=%u\n",
2125 EXT4_I(inode)->i_reserved_data_blocks);
2126 printk(KERN_CRIT "i_reserved_meta_blocks=%u\n",
2127 EXT4_I(inode)->i_reserved_meta_blocks);
2132 * mpage_da_map_blocks - go through given space
2134 * @mpd - bh describing space
2136 * The function skips space we know is already mapped to disk blocks.
2139 static int mpage_da_map_blocks(struct mpage_da_data *mpd)
2141 int err, blks, get_blocks_flags;
2142 struct buffer_head new;
2143 sector_t next = mpd->b_blocknr;
2144 unsigned max_blocks = mpd->b_size >> mpd->inode->i_blkbits;
2145 loff_t disksize = EXT4_I(mpd->inode)->i_disksize;
2146 handle_t *handle = NULL;
2149 * We consider only non-mapped and non-allocated blocks
2151 if ((mpd->b_state & (1 << BH_Mapped)) &&
2152 !(mpd->b_state & (1 << BH_Delay)) &&
2153 !(mpd->b_state & (1 << BH_Unwritten)))
2157 * If we didn't accumulate anything to write simply return
2162 handle = ext4_journal_current_handle();
2166 * Call ext4_get_blocks() to allocate any delayed allocation
2167 * blocks, or to convert an uninitialized extent to be
2168 * initialized (in the case where we have written into
2169 * one or more preallocated blocks).
2171 * We pass in the magic EXT4_GET_BLOCKS_DELALLOC_RESERVE to
2172 * indicate that we are on the delayed allocation path. This
2173 * affects functions in many different parts of the allocation
2174 * call path. This flag exists primarily because we don't
2175 * want to change *many* call functions, so ext4_get_blocks()
2176 * will set the magic i_delalloc_reserved_flag once the
2177 * inode's allocation semaphore is taken.
2179 * If the blocks in questions were delalloc blocks, set
2180 * EXT4_GET_BLOCKS_DELALLOC_RESERVE so the delalloc accounting
2181 * variables are updated after the blocks have been allocated.
2184 get_blocks_flags = (EXT4_GET_BLOCKS_CREATE |
2185 EXT4_GET_BLOCKS_DELALLOC_RESERVE);
2186 if (mpd->b_state & (1 << BH_Delay))
2187 get_blocks_flags |= EXT4_GET_BLOCKS_UPDATE_RESERVE_SPACE;
2188 blks = ext4_get_blocks(handle, mpd->inode, next, max_blocks,
2189 &new, get_blocks_flags);
2193 * If get block returns with error we simply
2194 * return. Later writepage will redirty the page and
2195 * writepages will find the dirty page again
2200 if (err == -ENOSPC &&
2201 ext4_count_free_blocks(mpd->inode->i_sb)) {
2207 * get block failure will cause us to loop in
2208 * writepages, because a_ops->writepage won't be able
2209 * to make progress. The page will be redirtied by
2210 * writepage and writepages will again try to write
2213 ext4_msg(mpd->inode->i_sb, KERN_CRIT,
2214 "delayed block allocation failed for inode %lu at "
2215 "logical offset %llu with max blocks %zd with "
2216 "error %d\n", mpd->inode->i_ino,
2217 (unsigned long long) next,
2218 mpd->b_size >> mpd->inode->i_blkbits, err);
2219 printk(KERN_CRIT "This should not happen!! "
2220 "Data will be lost\n");
2221 if (err == -ENOSPC) {
2222 ext4_print_free_blocks(mpd->inode);
2224 /* invalidate all the pages */
2225 ext4_da_block_invalidatepages(mpd, next,
2226 mpd->b_size >> mpd->inode->i_blkbits);
2231 new.b_size = (blks << mpd->inode->i_blkbits);
2233 if (buffer_new(&new))
2234 __unmap_underlying_blocks(mpd->inode, &new);
2237 * If blocks are delayed marked, we need to
2238 * put actual blocknr and drop delayed bit
2240 if ((mpd->b_state & (1 << BH_Delay)) ||
2241 (mpd->b_state & (1 << BH_Unwritten)))
2242 mpage_put_bnr_to_bhs(mpd, next, &new);
2244 if (ext4_should_order_data(mpd->inode)) {
2245 err = ext4_jbd2_file_inode(handle, mpd->inode);
2251 * Update on-disk size along with block allocation.
2253 disksize = ((loff_t) next + blks) << mpd->inode->i_blkbits;
2254 if (disksize > i_size_read(mpd->inode))
2255 disksize = i_size_read(mpd->inode);
2256 if (disksize > EXT4_I(mpd->inode)->i_disksize) {
2257 ext4_update_i_disksize(mpd->inode, disksize);
2258 return ext4_mark_inode_dirty(handle, mpd->inode);
2264 #define BH_FLAGS ((1 << BH_Uptodate) | (1 << BH_Mapped) | \
2265 (1 << BH_Delay) | (1 << BH_Unwritten))
2268 * mpage_add_bh_to_extent - try to add one more block to extent of blocks
2270 * @mpd->lbh - extent of blocks
2271 * @logical - logical number of the block in the file
2272 * @bh - bh of the block (used to access block's state)
2274 * the function is used to collect contig. blocks in same state
2276 static void mpage_add_bh_to_extent(struct mpage_da_data *mpd,
2277 sector_t logical, size_t b_size,
2278 unsigned long b_state)
2281 int nrblocks = mpd->b_size >> mpd->inode->i_blkbits;
2283 /* check if thereserved journal credits might overflow */
2284 if (!(EXT4_I(mpd->inode)->i_flags & EXT4_EXTENTS_FL)) {
2285 if (nrblocks >= EXT4_MAX_TRANS_DATA) {
2287 * With non-extent format we are limited by the journal
2288 * credit available. Total credit needed to insert
2289 * nrblocks contiguous blocks is dependent on the
2290 * nrblocks. So limit nrblocks.
2293 } else if ((nrblocks + (b_size >> mpd->inode->i_blkbits)) >
2294 EXT4_MAX_TRANS_DATA) {
2296 * Adding the new buffer_head would make it cross the
2297 * allowed limit for which we have journal credit
2298 * reserved. So limit the new bh->b_size
2300 b_size = (EXT4_MAX_TRANS_DATA - nrblocks) <<
2301 mpd->inode->i_blkbits;
2302 /* we will do mpage_da_submit_io in the next loop */
2306 * First block in the extent
2308 if (mpd->b_size == 0) {
2309 mpd->b_blocknr = logical;
2310 mpd->b_size = b_size;
2311 mpd->b_state = b_state & BH_FLAGS;
2315 next = mpd->b_blocknr + nrblocks;
2317 * Can we merge the block to our big extent?
2319 if (logical == next && (b_state & BH_FLAGS) == mpd->b_state) {
2320 mpd->b_size += b_size;
2326 * We couldn't merge the block to our extent, so we
2327 * need to flush current extent and start new one
2329 if (mpage_da_map_blocks(mpd) == 0)
2330 mpage_da_submit_io(mpd);
2335 static int ext4_bh_delay_or_unwritten(handle_t *handle, struct buffer_head *bh)
2337 return (buffer_delay(bh) || buffer_unwritten(bh)) && buffer_dirty(bh);
2341 * __mpage_da_writepage - finds extent of pages and blocks
2343 * @page: page to consider
2344 * @wbc: not used, we just follow rules
2347 * The function finds extents of pages and scan them for all blocks.
2349 static int __mpage_da_writepage(struct page *page,
2350 struct writeback_control *wbc, void *data)
2352 struct mpage_da_data *mpd = data;
2353 struct inode *inode = mpd->inode;
2354 struct buffer_head *bh, *head;
2359 * Rest of the page in the page_vec
2360 * redirty then and skip then. We will
2361 * try to write them again after
2362 * starting a new transaction
2364 redirty_page_for_writepage(wbc, page);
2366 return MPAGE_DA_EXTENT_TAIL;
2369 * Can we merge this page to current extent?
2371 if (mpd->next_page != page->index) {
2373 * Nope, we can't. So, we map non-allocated blocks
2374 * and start IO on them using writepage()
2376 if (mpd->next_page != mpd->first_page) {
2377 if (mpage_da_map_blocks(mpd) == 0)
2378 mpage_da_submit_io(mpd);
2380 * skip rest of the page in the page_vec
2383 redirty_page_for_writepage(wbc, page);
2385 return MPAGE_DA_EXTENT_TAIL;
2389 * Start next extent of pages ...
2391 mpd->first_page = page->index;
2401 mpd->next_page = page->index + 1;
2402 logical = (sector_t) page->index <<
2403 (PAGE_CACHE_SHIFT - inode->i_blkbits);
2405 if (!page_has_buffers(page)) {
2406 mpage_add_bh_to_extent(mpd, logical, PAGE_CACHE_SIZE,
2407 (1 << BH_Dirty) | (1 << BH_Uptodate));
2409 return MPAGE_DA_EXTENT_TAIL;
2412 * Page with regular buffer heads, just add all dirty ones
2414 head = page_buffers(page);
2417 BUG_ON(buffer_locked(bh));
2419 * We need to try to allocate
2420 * unmapped blocks in the same page.
2421 * Otherwise we won't make progress
2422 * with the page in ext4_writepage
2424 if (ext4_bh_delay_or_unwritten(NULL, bh)) {
2425 mpage_add_bh_to_extent(mpd, logical,
2429 return MPAGE_DA_EXTENT_TAIL;
2430 } else if (buffer_dirty(bh) && (buffer_mapped(bh))) {
2432 * mapped dirty buffer. We need to update
2433 * the b_state because we look at
2434 * b_state in mpage_da_map_blocks. We don't
2435 * update b_size because if we find an
2436 * unmapped buffer_head later we need to
2437 * use the b_state flag of that buffer_head.
2439 if (mpd->b_size == 0)
2440 mpd->b_state = bh->b_state & BH_FLAGS;
2443 } while ((bh = bh->b_this_page) != head);
2450 * This is a special get_blocks_t callback which is used by
2451 * ext4_da_write_begin(). It will either return mapped block or
2452 * reserve space for a single block.
2454 * For delayed buffer_head we have BH_Mapped, BH_New, BH_Delay set.
2455 * We also have b_blocknr = -1 and b_bdev initialized properly
2457 * For unwritten buffer_head we have BH_Mapped, BH_New, BH_Unwritten set.
2458 * We also have b_blocknr = physicalblock mapping unwritten extent and b_bdev
2459 * initialized properly.
2461 static int ext4_da_get_block_prep(struct inode *inode, sector_t iblock,
2462 struct buffer_head *bh_result, int create)
2465 sector_t invalid_block = ~((sector_t) 0xffff);
2467 if (invalid_block < ext4_blocks_count(EXT4_SB(inode->i_sb)->s_es))
2470 BUG_ON(create == 0);
2471 BUG_ON(bh_result->b_size != inode->i_sb->s_blocksize);
2474 * first, we need to know whether the block is allocated already
2475 * preallocated blocks are unmapped but should treated
2476 * the same as allocated blocks.
2478 ret = ext4_get_blocks(NULL, inode, iblock, 1, bh_result, 0);
2479 if ((ret == 0) && !buffer_delay(bh_result)) {
2480 /* the block isn't (pre)allocated yet, let's reserve space */
2482 * XXX: __block_prepare_write() unmaps passed block,
2485 ret = ext4_da_reserve_space(inode, 1);
2487 /* not enough space to reserve */
2490 map_bh(bh_result, inode->i_sb, invalid_block);
2491 set_buffer_new(bh_result);
2492 set_buffer_delay(bh_result);
2493 } else if (ret > 0) {
2494 bh_result->b_size = (ret << inode->i_blkbits);
2495 if (buffer_unwritten(bh_result)) {
2496 /* A delayed write to unwritten bh should
2497 * be marked new and mapped. Mapped ensures
2498 * that we don't do get_block multiple times
2499 * when we write to the same offset and new
2500 * ensures that we do proper zero out for
2503 set_buffer_new(bh_result);
2504 set_buffer_mapped(bh_result);
2513 * This function is used as a standard get_block_t calback function
2514 * when there is no desire to allocate any blocks. It is used as a
2515 * callback function for block_prepare_write(), nobh_writepage(), and
2516 * block_write_full_page(). These functions should only try to map a
2517 * single block at a time.
2519 * Since this function doesn't do block allocations even if the caller
2520 * requests it by passing in create=1, it is critically important that
2521 * any caller checks to make sure that any buffer heads are returned
2522 * by this function are either all already mapped or marked for
2523 * delayed allocation before calling nobh_writepage() or
2524 * block_write_full_page(). Otherwise, b_blocknr could be left
2525 * unitialized, and the page write functions will be taken by
2528 static int noalloc_get_block_write(struct inode *inode, sector_t iblock,
2529 struct buffer_head *bh_result, int create)
2532 unsigned max_blocks = bh_result->b_size >> inode->i_blkbits;
2534 BUG_ON(bh_result->b_size != inode->i_sb->s_blocksize);
2537 * we don't want to do block allocation in writepage
2538 * so call get_block_wrap with create = 0
2540 ret = ext4_get_blocks(NULL, inode, iblock, max_blocks, bh_result, 0);
2542 bh_result->b_size = (ret << inode->i_blkbits);
2548 static int bget_one(handle_t *handle, struct buffer_head *bh)
2554 static int bput_one(handle_t *handle, struct buffer_head *bh)
2560 static int __ext4_journalled_writepage(struct page *page,
2563 struct address_space *mapping = page->mapping;
2564 struct inode *inode = mapping->host;
2565 struct buffer_head *page_bufs;
2566 handle_t *handle = NULL;
2570 page_bufs = page_buffers(page);
2572 walk_page_buffers(handle, page_bufs, 0, len, NULL, bget_one);
2573 /* As soon as we unlock the page, it can go away, but we have
2574 * references to buffers so we are safe */
2577 handle = ext4_journal_start(inode, ext4_writepage_trans_blocks(inode));
2578 if (IS_ERR(handle)) {
2579 ret = PTR_ERR(handle);
2583 ret = walk_page_buffers(handle, page_bufs, 0, len, NULL,
2584 do_journal_get_write_access);
2586 err = walk_page_buffers(handle, page_bufs, 0, len, NULL,
2590 err = ext4_journal_stop(handle);
2594 walk_page_buffers(handle, page_bufs, 0, len, NULL, bput_one);
2595 EXT4_I(inode)->i_state |= EXT4_STATE_JDATA;
2601 * Note that we don't need to start a transaction unless we're journaling data
2602 * because we should have holes filled from ext4_page_mkwrite(). We even don't
2603 * need to file the inode to the transaction's list in ordered mode because if
2604 * we are writing back data added by write(), the inode is already there and if
2605 * we are writing back data modified via mmap(), noone guarantees in which
2606 * transaction the data will hit the disk. In case we are journaling data, we
2607 * cannot start transaction directly because transaction start ranks above page
2608 * lock so we have to do some magic.
2610 * This function can get called via...
2611 * - ext4_da_writepages after taking page lock (have journal handle)
2612 * - journal_submit_inode_data_buffers (no journal handle)
2613 * - shrink_page_list via pdflush (no journal handle)
2614 * - grab_page_cache when doing write_begin (have journal handle)
2616 * We don't do any block allocation in this function. If we have page with
2617 * multiple blocks we need to write those buffer_heads that are mapped. This
2618 * is important for mmaped based write. So if we do with blocksize 1K
2619 * truncate(f, 1024);
2620 * a = mmap(f, 0, 4096);
2622 * truncate(f, 4096);
2623 * we have in the page first buffer_head mapped via page_mkwrite call back
2624 * but other bufer_heads would be unmapped but dirty(dirty done via the
2625 * do_wp_page). So writepage should write the first block. If we modify
2626 * the mmap area beyond 1024 we will again get a page_fault and the
2627 * page_mkwrite callback will do the block allocation and mark the
2628 * buffer_heads mapped.
2630 * We redirty the page if we have any buffer_heads that is either delay or
2631 * unwritten in the page.
2633 * We can get recursively called as show below.
2635 * ext4_writepage() -> kmalloc() -> __alloc_pages() -> page_launder() ->
2638 * But since we don't do any block allocation we should not deadlock.
2639 * Page also have the dirty flag cleared so we don't get recurive page_lock.
2641 static int ext4_writepage(struct page *page,
2642 struct writeback_control *wbc)
2647 struct buffer_head *page_bufs;
2648 struct inode *inode = page->mapping->host;
2650 trace_ext4_writepage(inode, page);
2651 size = i_size_read(inode);
2652 if (page->index == size >> PAGE_CACHE_SHIFT)
2653 len = size & ~PAGE_CACHE_MASK;
2655 len = PAGE_CACHE_SIZE;
2657 if (page_has_buffers(page)) {
2658 page_bufs = page_buffers(page);
2659 if (walk_page_buffers(NULL, page_bufs, 0, len, NULL,
2660 ext4_bh_delay_or_unwritten)) {
2662 * We don't want to do block allocation
2663 * So redirty the page and return
2664 * We may reach here when we do a journal commit
2665 * via journal_submit_inode_data_buffers.
2666 * If we don't have mapping block we just ignore
2667 * them. We can also reach here via shrink_page_list
2669 redirty_page_for_writepage(wbc, page);
2675 * The test for page_has_buffers() is subtle:
2676 * We know the page is dirty but it lost buffers. That means
2677 * that at some moment in time after write_begin()/write_end()
2678 * has been called all buffers have been clean and thus they
2679 * must have been written at least once. So they are all
2680 * mapped and we can happily proceed with mapping them
2681 * and writing the page.
2683 * Try to initialize the buffer_heads and check whether
2684 * all are mapped and non delay. We don't want to
2685 * do block allocation here.
2687 ret = block_prepare_write(page, 0, len,
2688 noalloc_get_block_write);
2690 page_bufs = page_buffers(page);
2691 /* check whether all are mapped and non delay */
2692 if (walk_page_buffers(NULL, page_bufs, 0, len, NULL,
2693 ext4_bh_delay_or_unwritten)) {
2694 redirty_page_for_writepage(wbc, page);
2700 * We can't do block allocation here
2701 * so just redity the page and unlock
2704 redirty_page_for_writepage(wbc, page);
2708 /* now mark the buffer_heads as dirty and uptodate */
2709 block_commit_write(page, 0, len);
2712 if (PageChecked(page) && ext4_should_journal_data(inode)) {
2714 * It's mmapped pagecache. Add buffers and journal it. There
2715 * doesn't seem much point in redirtying the page here.
2717 ClearPageChecked(page);
2718 return __ext4_journalled_writepage(page, len);
2721 if (test_opt(inode->i_sb, NOBH) && ext4_should_writeback_data(inode))
2722 ret = nobh_writepage(page, noalloc_get_block_write, wbc);
2724 ret = block_write_full_page(page, noalloc_get_block_write,
2731 * This is called via ext4_da_writepages() to
2732 * calulate the total number of credits to reserve to fit
2733 * a single extent allocation into a single transaction,
2734 * ext4_da_writpeages() will loop calling this before
2735 * the block allocation.
2738 static int ext4_da_writepages_trans_blocks(struct inode *inode)
2740 int max_blocks = EXT4_I(inode)->i_reserved_data_blocks;
2743 * With non-extent format the journal credit needed to
2744 * insert nrblocks contiguous block is dependent on
2745 * number of contiguous block. So we will limit
2746 * number of contiguous block to a sane value
2748 if (!(EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL) &&
2749 (max_blocks > EXT4_MAX_TRANS_DATA))
2750 max_blocks = EXT4_MAX_TRANS_DATA;
2752 return ext4_chunk_trans_blocks(inode, max_blocks);
2755 static int ext4_da_writepages(struct address_space *mapping,
2756 struct writeback_control *wbc)
2759 int range_whole = 0;
2760 handle_t *handle = NULL;
2761 struct mpage_da_data mpd;
2762 struct inode *inode = mapping->host;
2763 int no_nrwrite_index_update;
2764 int pages_written = 0;
2766 unsigned int max_pages;
2767 int range_cyclic, cycled = 1, io_done = 0;
2768 int needed_blocks, ret = 0;
2769 long desired_nr_to_write, nr_to_writebump = 0;
2770 loff_t range_start = wbc->range_start;
2771 struct ext4_sb_info *sbi = EXT4_SB(mapping->host->i_sb);
2773 trace_ext4_da_writepages(inode, wbc);
2776 * No pages to write? This is mainly a kludge to avoid starting
2777 * a transaction for special inodes like journal inode on last iput()
2778 * because that could violate lock ordering on umount
2780 if (!mapping->nrpages || !mapping_tagged(mapping, PAGECACHE_TAG_DIRTY))
2784 * If the filesystem has aborted, it is read-only, so return
2785 * right away instead of dumping stack traces later on that
2786 * will obscure the real source of the problem. We test
2787 * EXT4_MF_FS_ABORTED instead of sb->s_flag's MS_RDONLY because
2788 * the latter could be true if the filesystem is mounted
2789 * read-only, and in that case, ext4_da_writepages should
2790 * *never* be called, so if that ever happens, we would want
2793 if (unlikely(sbi->s_mount_flags & EXT4_MF_FS_ABORTED))
2796 if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX)
2799 range_cyclic = wbc->range_cyclic;
2800 if (wbc->range_cyclic) {
2801 index = mapping->writeback_index;
2804 wbc->range_start = index << PAGE_CACHE_SHIFT;
2805 wbc->range_end = LLONG_MAX;
2806 wbc->range_cyclic = 0;
2808 index = wbc->range_start >> PAGE_CACHE_SHIFT;
2811 * This works around two forms of stupidity. The first is in
2812 * the writeback code, which caps the maximum number of pages
2813 * written to be 1024 pages. This is wrong on multiple
2814 * levels; different architectues have a different page size,
2815 * which changes the maximum amount of data which gets
2816 * written. Secondly, 4 megabytes is way too small. XFS
2817 * forces this value to be 16 megabytes by multiplying
2818 * nr_to_write parameter by four, and then relies on its
2819 * allocator to allocate larger extents to make them
2820 * contiguous. Unfortunately this brings us to the second
2821 * stupidity, which is that ext4's mballoc code only allocates
2822 * at most 2048 blocks. So we force contiguous writes up to
2823 * the number of dirty blocks in the inode, or
2824 * sbi->max_writeback_mb_bump whichever is smaller.
2826 max_pages = sbi->s_max_writeback_mb_bump << (20 - PAGE_CACHE_SHIFT);
2827 if (!range_cyclic && range_whole)
2828 desired_nr_to_write = wbc->nr_to_write * 8;
2830 desired_nr_to_write = ext4_num_dirty_pages(inode, index,
2832 if (desired_nr_to_write > max_pages)
2833 desired_nr_to_write = max_pages;
2835 if (wbc->nr_to_write < desired_nr_to_write) {
2836 nr_to_writebump = desired_nr_to_write - wbc->nr_to_write;
2837 wbc->nr_to_write = desired_nr_to_write;
2841 mpd.inode = mapping->host;
2844 * we don't want write_cache_pages to update
2845 * nr_to_write and writeback_index
2847 no_nrwrite_index_update = wbc->no_nrwrite_index_update;
2848 wbc->no_nrwrite_index_update = 1;
2849 pages_skipped = wbc->pages_skipped;
2852 while (!ret && wbc->nr_to_write > 0) {
2855 * we insert one extent at a time. So we need
2856 * credit needed for single extent allocation.
2857 * journalled mode is currently not supported
2860 BUG_ON(ext4_should_journal_data(inode));
2861 needed_blocks = ext4_da_writepages_trans_blocks(inode);
2863 /* start a new transaction*/
2864 handle = ext4_journal_start(inode, needed_blocks);
2865 if (IS_ERR(handle)) {
2866 ret = PTR_ERR(handle);
2867 ext4_msg(inode->i_sb, KERN_CRIT, "%s: jbd2_start: "
2868 "%ld pages, ino %lu; err %d\n", __func__,
2869 wbc->nr_to_write, inode->i_ino, ret);
2870 goto out_writepages;
2874 * Now call __mpage_da_writepage to find the next
2875 * contiguous region of logical blocks that need
2876 * blocks to be allocated by ext4. We don't actually
2877 * submit the blocks for I/O here, even though
2878 * write_cache_pages thinks it will, and will set the
2879 * pages as clean for write before calling
2880 * __mpage_da_writepage().
2888 mpd.pages_written = 0;
2890 ret = write_cache_pages(mapping, wbc, __mpage_da_writepage,
2893 * If we have a contigous extent of pages and we
2894 * haven't done the I/O yet, map the blocks and submit
2897 if (!mpd.io_done && mpd.next_page != mpd.first_page) {
2898 if (mpage_da_map_blocks(&mpd) == 0)
2899 mpage_da_submit_io(&mpd);
2901 ret = MPAGE_DA_EXTENT_TAIL;
2903 trace_ext4_da_write_pages(inode, &mpd);
2904 wbc->nr_to_write -= mpd.pages_written;
2906 ext4_journal_stop(handle);
2908 if ((mpd.retval == -ENOSPC) && sbi->s_journal) {
2909 /* commit the transaction which would
2910 * free blocks released in the transaction
2913 jbd2_journal_force_commit_nested(sbi->s_journal);
2914 wbc->pages_skipped = pages_skipped;
2916 } else if (ret == MPAGE_DA_EXTENT_TAIL) {
2918 * got one extent now try with
2921 pages_written += mpd.pages_written;
2922 wbc->pages_skipped = pages_skipped;
2925 } else if (wbc->nr_to_write)
2927 * There is no more writeout needed
2928 * or we requested for a noblocking writeout
2929 * and we found the device congested
2933 if (!io_done && !cycled) {
2936 wbc->range_start = index << PAGE_CACHE_SHIFT;
2937 wbc->range_end = mapping->writeback_index - 1;
2940 if (pages_skipped != wbc->pages_skipped)
2941 ext4_msg(inode->i_sb, KERN_CRIT,
2942 "This should not happen leaving %s "
2943 "with nr_to_write = %ld ret = %d\n",
2944 __func__, wbc->nr_to_write, ret);
2947 index += pages_written;
2948 wbc->range_cyclic = range_cyclic;
2949 if (wbc->range_cyclic || (range_whole && wbc->nr_to_write > 0))
2951 * set the writeback_index so that range_cyclic
2952 * mode will write it back later
2954 mapping->writeback_index = index;
2957 if (!no_nrwrite_index_update)
2958 wbc->no_nrwrite_index_update = 0;
2959 if (wbc->nr_to_write > nr_to_writebump)
2960 wbc->nr_to_write -= nr_to_writebump;
2961 wbc->range_start = range_start;
2962 trace_ext4_da_writepages_result(inode, wbc, ret, pages_written);
2966 #define FALL_BACK_TO_NONDELALLOC 1
2967 static int ext4_nonda_switch(struct super_block *sb)
2969 s64 free_blocks, dirty_blocks;
2970 struct ext4_sb_info *sbi = EXT4_SB(sb);
2973 * switch to non delalloc mode if we are running low
2974 * on free block. The free block accounting via percpu
2975 * counters can get slightly wrong with percpu_counter_batch getting
2976 * accumulated on each CPU without updating global counters
2977 * Delalloc need an accurate free block accounting. So switch
2978 * to non delalloc when we are near to error range.
2980 free_blocks = percpu_counter_read_positive(&sbi->s_freeblocks_counter);
2981 dirty_blocks = percpu_counter_read_positive(&sbi->s_dirtyblocks_counter);
2982 if (2 * free_blocks < 3 * dirty_blocks ||
2983 free_blocks < (dirty_blocks + EXT4_FREEBLOCKS_WATERMARK)) {
2985 * free block count is less that 150% of dirty blocks
2986 * or free blocks is less that watermark
2993 static int ext4_da_write_begin(struct file *file, struct address_space *mapping,
2994 loff_t pos, unsigned len, unsigned flags,
2995 struct page **pagep, void **fsdata)
2997 int ret, retries = 0;
3001 struct inode *inode = mapping->host;
3004 index = pos >> PAGE_CACHE_SHIFT;
3005 from = pos & (PAGE_CACHE_SIZE - 1);
3008 if (ext4_nonda_switch(inode->i_sb)) {
3009 *fsdata = (void *)FALL_BACK_TO_NONDELALLOC;
3010 return ext4_write_begin(file, mapping, pos,
3011 len, flags, pagep, fsdata);
3013 *fsdata = (void *)0;
3014 trace_ext4_da_write_begin(inode, pos, len, flags);
3017 * With delayed allocation, we don't log the i_disksize update
3018 * if there is delayed block allocation. But we still need
3019 * to journalling the i_disksize update if writes to the end
3020 * of file which has an already mapped buffer.
3022 handle = ext4_journal_start(inode, 1);
3023 if (IS_ERR(handle)) {
3024 ret = PTR_ERR(handle);
3027 /* We cannot recurse into the filesystem as the transaction is already
3029 flags |= AOP_FLAG_NOFS;
3031 page = grab_cache_page_write_begin(mapping, index, flags);
3033 ext4_journal_stop(handle);
3039 ret = block_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
3040 ext4_da_get_block_prep);
3043 ext4_journal_stop(handle);
3044 page_cache_release(page);
3046 * block_write_begin may have instantiated a few blocks
3047 * outside i_size. Trim these off again. Don't need
3048 * i_size_read because we hold i_mutex.
3050 if (pos + len > inode->i_size)
3051 ext4_truncate(inode);
3054 if (ret == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
3061 * Check if we should update i_disksize
3062 * when write to the end of file but not require block allocation
3064 static int ext4_da_should_update_i_disksize(struct page *page,
3065 unsigned long offset)
3067 struct buffer_head *bh;
3068 struct inode *inode = page->mapping->host;
3072 bh = page_buffers(page);
3073 idx = offset >> inode->i_blkbits;
3075 for (i = 0; i < idx; i++)
3076 bh = bh->b_this_page;
3078 if (!buffer_mapped(bh) || (buffer_delay(bh)) || buffer_unwritten(bh))
3083 static int ext4_da_write_end(struct file *file,
3084 struct address_space *mapping,
3085 loff_t pos, unsigned len, unsigned copied,
3086 struct page *page, void *fsdata)
3088 struct inode *inode = mapping->host;
3090 handle_t *handle = ext4_journal_current_handle();
3092 unsigned long start, end;
3093 int write_mode = (int)(unsigned long)fsdata;
3095 if (write_mode == FALL_BACK_TO_NONDELALLOC) {
3096 if (ext4_should_order_data(inode)) {
3097 return ext4_ordered_write_end(file, mapping, pos,
3098 len, copied, page, fsdata);
3099 } else if (ext4_should_writeback_data(inode)) {
3100 return ext4_writeback_write_end(file, mapping, pos,
3101 len, copied, page, fsdata);
3107 trace_ext4_da_write_end(inode, pos, len, copied);
3108 start = pos & (PAGE_CACHE_SIZE - 1);
3109 end = start + copied - 1;
3112 * generic_write_end() will run mark_inode_dirty() if i_size
3113 * changes. So let's piggyback the i_disksize mark_inode_dirty
3117 new_i_size = pos + copied;
3118 if (new_i_size > EXT4_I(inode)->i_disksize) {
3119 if (ext4_da_should_update_i_disksize(page, end)) {
3120 down_write(&EXT4_I(inode)->i_data_sem);
3121 if (new_i_size > EXT4_I(inode)->i_disksize) {
3123 * Updating i_disksize when extending file
3124 * without needing block allocation
3126 if (ext4_should_order_data(inode))
3127 ret = ext4_jbd2_file_inode(handle,
3130 EXT4_I(inode)->i_disksize = new_i_size;
3132 up_write(&EXT4_I(inode)->i_data_sem);
3133 /* We need to mark inode dirty even if
3134 * new_i_size is less that inode->i_size
3135 * bu greater than i_disksize.(hint delalloc)
3137 ext4_mark_inode_dirty(handle, inode);
3140 ret2 = generic_write_end(file, mapping, pos, len, copied,
3145 ret2 = ext4_journal_stop(handle);
3149 return ret ? ret : copied;
3152 static void ext4_da_invalidatepage(struct page *page, unsigned long offset)
3155 * Drop reserved blocks
3157 BUG_ON(!PageLocked(page));
3158 if (!page_has_buffers(page))
3161 ext4_da_page_release_reservation(page, offset);
3164 ext4_invalidatepage(page, offset);
3170 * Force all delayed allocation blocks to be allocated for a given inode.
3172 int ext4_alloc_da_blocks(struct inode *inode)
3174 trace_ext4_alloc_da_blocks(inode);
3176 if (!EXT4_I(inode)->i_reserved_data_blocks &&
3177 !EXT4_I(inode)->i_reserved_meta_blocks)
3181 * We do something simple for now. The filemap_flush() will
3182 * also start triggering a write of the data blocks, which is
3183 * not strictly speaking necessary (and for users of
3184 * laptop_mode, not even desirable). However, to do otherwise
3185 * would require replicating code paths in:
3187 * ext4_da_writepages() ->
3188 * write_cache_pages() ---> (via passed in callback function)
3189 * __mpage_da_writepage() -->
3190 * mpage_add_bh_to_extent()
3191 * mpage_da_map_blocks()
3193 * The problem is that write_cache_pages(), located in
3194 * mm/page-writeback.c, marks pages clean in preparation for
3195 * doing I/O, which is not desirable if we're not planning on
3198 * We could call write_cache_pages(), and then redirty all of
3199 * the pages by calling redirty_page_for_writeback() but that
3200 * would be ugly in the extreme. So instead we would need to
3201 * replicate parts of the code in the above functions,
3202 * simplifying them becuase we wouldn't actually intend to
3203 * write out the pages, but rather only collect contiguous
3204 * logical block extents, call the multi-block allocator, and
3205 * then update the buffer heads with the block allocations.
3207 * For now, though, we'll cheat by calling filemap_flush(),
3208 * which will map the blocks, and start the I/O, but not
3209 * actually wait for the I/O to complete.
3211 return filemap_flush(inode->i_mapping);
3215 * bmap() is special. It gets used by applications such as lilo and by
3216 * the swapper to find the on-disk block of a specific piece of data.
3218 * Naturally, this is dangerous if the block concerned is still in the
3219 * journal. If somebody makes a swapfile on an ext4 data-journaling
3220 * filesystem and enables swap, then they may get a nasty shock when the
3221 * data getting swapped to that swapfile suddenly gets overwritten by
3222 * the original zero's written out previously to the journal and
3223 * awaiting writeback in the kernel's buffer cache.
3225 * So, if we see any bmap calls here on a modified, data-journaled file,
3226 * take extra steps to flush any blocks which might be in the cache.
3228 static sector_t ext4_bmap(struct address_space *mapping, sector_t block)
3230 struct inode *inode = mapping->host;
3234 if (mapping_tagged(mapping, PAGECACHE_TAG_DIRTY) &&
3235 test_opt(inode->i_sb, DELALLOC)) {
3237 * With delalloc we want to sync the file
3238 * so that we can make sure we allocate
3241 filemap_write_and_wait(mapping);
3244 if (EXT4_JOURNAL(inode) && EXT4_I(inode)->i_state & EXT4_STATE_JDATA) {
3246 * This is a REALLY heavyweight approach, but the use of
3247 * bmap on dirty files is expected to be extremely rare:
3248 * only if we run lilo or swapon on a freshly made file
3249 * do we expect this to happen.
3251 * (bmap requires CAP_SYS_RAWIO so this does not
3252 * represent an unprivileged user DOS attack --- we'd be
3253 * in trouble if mortal users could trigger this path at
3256 * NB. EXT4_STATE_JDATA is not set on files other than
3257 * regular files. If somebody wants to bmap a directory
3258 * or symlink and gets confused because the buffer
3259 * hasn't yet been flushed to disk, they deserve
3260 * everything they get.
3263 EXT4_I(inode)->i_state &= ~EXT4_STATE_JDATA;
3264 journal = EXT4_JOURNAL(inode);
3265 jbd2_journal_lock_updates(journal);
3266 err = jbd2_journal_flush(journal);
3267 jbd2_journal_unlock_updates(journal);
3273 return generic_block_bmap(mapping, block, ext4_get_block);
3276 static int ext4_readpage(struct file *file, struct page *page)
3278 return mpage_readpage(page, ext4_get_block);
3282 ext4_readpages(struct file *file, struct address_space *mapping,
3283 struct list_head *pages, unsigned nr_pages)
3285 return mpage_readpages(mapping, pages, nr_pages, ext4_get_block);
3288 static void ext4_invalidatepage(struct page *page, unsigned long offset)
3290 journal_t *journal = EXT4_JOURNAL(page->mapping->host);
3293 * If it's a full truncate we just forget about the pending dirtying
3296 ClearPageChecked(page);
3299 jbd2_journal_invalidatepage(journal, page, offset);
3301 block_invalidatepage(page, offset);
3304 static int ext4_releasepage(struct page *page, gfp_t wait)
3306 journal_t *journal = EXT4_JOURNAL(page->mapping->host);
3308 WARN_ON(PageChecked(page));
3309 if (!page_has_buffers(page))
3312 return jbd2_journal_try_to_free_buffers(journal, page, wait);
3314 return try_to_free_buffers(page);
3318 * O_DIRECT for ext3 (or indirect map) based files
3320 * If the O_DIRECT write will extend the file then add this inode to the
3321 * orphan list. So recovery will truncate it back to the original size
3322 * if the machine crashes during the write.
3324 * If the O_DIRECT write is intantiating holes inside i_size and the machine
3325 * crashes then stale disk data _may_ be exposed inside the file. But current
3326 * VFS code falls back into buffered path in that case so we are safe.
3328 static ssize_t ext4_ind_direct_IO(int rw, struct kiocb *iocb,
3329 const struct iovec *iov, loff_t offset,
3330 unsigned long nr_segs)
3332 struct file *file = iocb->ki_filp;
3333 struct inode *inode = file->f_mapping->host;
3334 struct ext4_inode_info *ei = EXT4_I(inode);
3338 size_t count = iov_length(iov, nr_segs);
3342 loff_t final_size = offset + count;
3344 if (final_size > inode->i_size) {
3345 /* Credits for sb + inode write */
3346 handle = ext4_journal_start(inode, 2);
3347 if (IS_ERR(handle)) {
3348 ret = PTR_ERR(handle);
3351 ret = ext4_orphan_add(handle, inode);
3353 ext4_journal_stop(handle);
3357 ei->i_disksize = inode->i_size;
3358 ext4_journal_stop(handle);
3363 ret = blockdev_direct_IO(rw, iocb, inode, inode->i_sb->s_bdev, iov,
3365 ext4_get_block, NULL);
3366 if (ret == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
3372 /* Credits for sb + inode write */
3373 handle = ext4_journal_start(inode, 2);
3374 if (IS_ERR(handle)) {
3375 /* This is really bad luck. We've written the data
3376 * but cannot extend i_size. Bail out and pretend
3377 * the write failed... */
3378 ret = PTR_ERR(handle);
3382 ext4_orphan_del(handle, inode);
3384 loff_t end = offset + ret;
3385 if (end > inode->i_size) {
3386 ei->i_disksize = end;
3387 i_size_write(inode, end);
3389 * We're going to return a positive `ret'
3390 * here due to non-zero-length I/O, so there's
3391 * no way of reporting error returns from
3392 * ext4_mark_inode_dirty() to userspace. So
3395 ext4_mark_inode_dirty(handle, inode);
3398 err = ext4_journal_stop(handle);
3406 static int ext4_get_block_dio_write(struct inode *inode, sector_t iblock,
3407 struct buffer_head *bh_result, int create)
3409 handle_t *handle = NULL;
3411 unsigned max_blocks = bh_result->b_size >> inode->i_blkbits;
3414 ext4_debug("ext4_get_block_dio_write: inode %lu, create flag %d\n",
3415 inode->i_ino, create);
3417 * DIO VFS code passes create = 0 flag for write to
3418 * the middle of file. It does this to avoid block
3419 * allocation for holes, to prevent expose stale data
3420 * out when there is parallel buffered read (which does
3421 * not hold the i_mutex lock) while direct IO write has
3422 * not completed. DIO request on holes finally falls back
3423 * to buffered IO for this reason.
3425 * For ext4 extent based file, since we support fallocate,
3426 * new allocated extent as uninitialized, for holes, we
3427 * could fallocate blocks for holes, thus parallel
3428 * buffered IO read will zero out the page when read on
3429 * a hole while parallel DIO write to the hole has not completed.
3431 * when we come here, we know it's a direct IO write to
3432 * to the middle of file (<i_size)
3433 * so it's safe to override the create flag from VFS.
3435 create = EXT4_GET_BLOCKS_DIO_CREATE_EXT;
3437 if (max_blocks > DIO_MAX_BLOCKS)
3438 max_blocks = DIO_MAX_BLOCKS;
3439 dio_credits = ext4_chunk_trans_blocks(inode, max_blocks);
3440 handle = ext4_journal_start(inode, dio_credits);
3441 if (IS_ERR(handle)) {
3442 ret = PTR_ERR(handle);
3445 ret = ext4_get_blocks(handle, inode, iblock, max_blocks, bh_result,
3448 bh_result->b_size = (ret << inode->i_blkbits);
3451 ext4_journal_stop(handle);
3456 static void ext4_free_io_end(ext4_io_end_t *io)
3462 static void dump_aio_dio_list(struct inode * inode)
3465 struct list_head *cur, *before, *after;
3466 ext4_io_end_t *io, *io0, *io1;
3468 if (list_empty(&EXT4_I(inode)->i_aio_dio_complete_list)){
3469 ext4_debug("inode %lu aio dio list is empty\n", inode->i_ino);
3473 ext4_debug("Dump inode %lu aio_dio_completed_IO list \n", inode->i_ino);
3474 list_for_each_entry(io, &EXT4_I(inode)->i_aio_dio_complete_list, list){
3477 io0 = container_of(before, ext4_io_end_t, list);
3479 io1 = container_of(after, ext4_io_end_t, list);
3481 ext4_debug("io 0x%p from inode %lu,prev 0x%p,next 0x%p\n",
3482 io, inode->i_ino, io0, io1);
3488 * check a range of space and convert unwritten extents to written.
3490 static int ext4_end_aio_dio_nolock(ext4_io_end_t *io)
3492 struct inode *inode = io->inode;
3493 loff_t offset = io->offset;
3494 size_t size = io->size;
3497 ext4_debug("end_aio_dio_onlock: io 0x%p from inode %lu,list->next 0x%p,"
3498 "list->prev 0x%p\n",
3499 io, inode->i_ino, io->list.next, io->list.prev);
3501 if (list_empty(&io->list))
3504 if (io->flag != DIO_AIO_UNWRITTEN)
3507 if (offset + size <= i_size_read(inode))
3508 ret = ext4_convert_unwritten_extents(inode, offset, size);
3511 printk(KERN_EMERG "%s: failed to convert unwritten"
3512 "extents to written extents, error is %d"
3513 " io is still on inode %lu aio dio list\n",
3514 __func__, ret, inode->i_ino);
3518 /* clear the DIO AIO unwritten flag */
3523 * work on completed aio dio IO, to convert unwritten extents to extents
3525 static void ext4_end_aio_dio_work(struct work_struct *work)
3527 ext4_io_end_t *io = container_of(work, ext4_io_end_t, work);
3528 struct inode *inode = io->inode;
3531 mutex_lock(&inode->i_mutex);
3532 ret = ext4_end_aio_dio_nolock(io);
3534 if (!list_empty(&io->list))
3535 list_del_init(&io->list);
3536 ext4_free_io_end(io);
3538 mutex_unlock(&inode->i_mutex);
3541 * This function is called from ext4_sync_file().
3543 * When AIO DIO IO is completed, the work to convert unwritten
3544 * extents to written is queued on workqueue but may not get immediately
3545 * scheduled. When fsync is called, we need to ensure the
3546 * conversion is complete before fsync returns.
3547 * The inode keeps track of a list of completed AIO from DIO path
3548 * that might needs to do the conversion. This function walks through
3549 * the list and convert the related unwritten extents to written.
3551 int flush_aio_dio_completed_IO(struct inode *inode)
3557 if (list_empty(&EXT4_I(inode)->i_aio_dio_complete_list))
3560 dump_aio_dio_list(inode);
3561 while (!list_empty(&EXT4_I(inode)->i_aio_dio_complete_list)){
3562 io = list_entry(EXT4_I(inode)->i_aio_dio_complete_list.next,
3563 ext4_io_end_t, list);
3565 * Calling ext4_end_aio_dio_nolock() to convert completed
3568 * When ext4_sync_file() is called, run_queue() may already
3569 * about to flush the work corresponding to this io structure.
3570 * It will be upset if it founds the io structure related
3571 * to the work-to-be schedule is freed.
3573 * Thus we need to keep the io structure still valid here after
3574 * convertion finished. The io structure has a flag to
3575 * avoid double converting from both fsync and background work
3578 ret = ext4_end_aio_dio_nolock(io);
3582 list_del_init(&io->list);
3584 return (ret2 < 0) ? ret2 : 0;
3587 static ext4_io_end_t *ext4_init_io_end (struct inode *inode)
3589 ext4_io_end_t *io = NULL;
3591 io = kmalloc(sizeof(*io), GFP_NOFS);
3600 INIT_WORK(&io->work, ext4_end_aio_dio_work);
3601 INIT_LIST_HEAD(&io->list);
3607 static void ext4_end_io_dio(struct kiocb *iocb, loff_t offset,
3608 ssize_t size, void *private)
3610 ext4_io_end_t *io_end = iocb->private;
3611 struct workqueue_struct *wq;
3613 /* if not async direct IO or dio with 0 bytes write, just return */
3614 if (!io_end || !size)
3617 ext_debug("ext4_end_io_dio(): io_end 0x%p"
3618 "for inode %lu, iocb 0x%p, offset %llu, size %llu\n",
3619 iocb->private, io_end->inode->i_ino, iocb, offset,
3622 /* if not aio dio with unwritten extents, just free io and return */
3623 if (io_end->flag != DIO_AIO_UNWRITTEN){
3624 ext4_free_io_end(io_end);
3625 iocb->private = NULL;
3629 io_end->offset = offset;
3630 io_end->size = size;
3631 wq = EXT4_SB(io_end->inode->i_sb)->dio_unwritten_wq;
3633 /* queue the work to convert unwritten extents to written */
3634 queue_work(wq, &io_end->work);
3636 /* Add the io_end to per-inode completed aio dio list*/
3637 list_add_tail(&io_end->list,
3638 &EXT4_I(io_end->inode)->i_aio_dio_complete_list);
3639 iocb->private = NULL;
3642 * For ext4 extent files, ext4 will do direct-io write to holes,
3643 * preallocated extents, and those write extend the file, no need to
3644 * fall back to buffered IO.
3646 * For holes, we fallocate those blocks, mark them as unintialized
3647 * If those blocks were preallocated, we mark sure they are splited, but
3648 * still keep the range to write as unintialized.
3650 * The unwrritten extents will be converted to written when DIO is completed.
3651 * For async direct IO, since the IO may still pending when return, we
3652 * set up an end_io call back function, which will do the convertion
3653 * when async direct IO completed.
3655 * If the O_DIRECT write will extend the file then add this inode to the
3656 * orphan list. So recovery will truncate it back to the original size
3657 * if the machine crashes during the write.
3660 static ssize_t ext4_ext_direct_IO(int rw, struct kiocb *iocb,
3661 const struct iovec *iov, loff_t offset,
3662 unsigned long nr_segs)
3664 struct file *file = iocb->ki_filp;
3665 struct inode *inode = file->f_mapping->host;
3667 size_t count = iov_length(iov, nr_segs);
3669 loff_t final_size = offset + count;
3670 if (rw == WRITE && final_size <= inode->i_size) {
3672 * We could direct write to holes and fallocate.
3674 * Allocated blocks to fill the hole are marked as uninitialized
3675 * to prevent paralel buffered read to expose the stale data
3676 * before DIO complete the data IO.
3678 * As to previously fallocated extents, ext4 get_block
3679 * will just simply mark the buffer mapped but still
3680 * keep the extents uninitialized.
3682 * for non AIO case, we will convert those unwritten extents
3683 * to written after return back from blockdev_direct_IO.
3685 * for async DIO, the conversion needs to be defered when
3686 * the IO is completed. The ext4 end_io callback function
3687 * will be called to take care of the conversion work.
3688 * Here for async case, we allocate an io_end structure to
3691 iocb->private = NULL;
3692 EXT4_I(inode)->cur_aio_dio = NULL;
3693 if (!is_sync_kiocb(iocb)) {
3694 iocb->private = ext4_init_io_end(inode);
3698 * we save the io structure for current async
3699 * direct IO, so that later ext4_get_blocks()
3700 * could flag the io structure whether there
3701 * is a unwritten extents needs to be converted
3702 * when IO is completed.
3704 EXT4_I(inode)->cur_aio_dio = iocb->private;
3707 ret = blockdev_direct_IO(rw, iocb, inode,
3708 inode->i_sb->s_bdev, iov,
3710 ext4_get_block_dio_write,
3713 EXT4_I(inode)->cur_aio_dio = NULL;
3715 * The io_end structure takes a reference to the inode,
3716 * that structure needs to be destroyed and the
3717 * reference to the inode need to be dropped, when IO is
3718 * complete, even with 0 byte write, or failed.
3720 * In the successful AIO DIO case, the io_end structure will be
3721 * desctroyed and the reference to the inode will be dropped
3722 * after the end_io call back function is called.
3724 * In the case there is 0 byte write, or error case, since
3725 * VFS direct IO won't invoke the end_io call back function,
3726 * we need to free the end_io structure here.
3728 if (ret != -EIOCBQUEUED && ret <= 0 && iocb->private) {
3729 ext4_free_io_end(iocb->private);
3730 iocb->private = NULL;
3731 } else if (ret > 0 && (EXT4_I(inode)->i_state &
3732 EXT4_STATE_DIO_UNWRITTEN)) {
3735 * for non AIO case, since the IO is already
3736 * completed, we could do the convertion right here
3738 err = ext4_convert_unwritten_extents(inode,
3742 EXT4_I(inode)->i_state &= ~EXT4_STATE_DIO_UNWRITTEN;
3747 /* for write the the end of file case, we fall back to old way */
3748 return ext4_ind_direct_IO(rw, iocb, iov, offset, nr_segs);
3751 static ssize_t ext4_direct_IO(int rw, struct kiocb *iocb,
3752 const struct iovec *iov, loff_t offset,
3753 unsigned long nr_segs)
3755 struct file *file = iocb->ki_filp;
3756 struct inode *inode = file->f_mapping->host;
3758 if (EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL)
3759 return ext4_ext_direct_IO(rw, iocb, iov, offset, nr_segs);
3761 return ext4_ind_direct_IO(rw, iocb, iov, offset, nr_segs);
3765 * Pages can be marked dirty completely asynchronously from ext4's journalling
3766 * activity. By filemap_sync_pte(), try_to_unmap_one(), etc. We cannot do
3767 * much here because ->set_page_dirty is called under VFS locks. The page is
3768 * not necessarily locked.
3770 * We cannot just dirty the page and leave attached buffers clean, because the
3771 * buffers' dirty state is "definitive". We cannot just set the buffers dirty
3772 * or jbddirty because all the journalling code will explode.
3774 * So what we do is to mark the page "pending dirty" and next time writepage
3775 * is called, propagate that into the buffers appropriately.
3777 static int ext4_journalled_set_page_dirty(struct page *page)
3779 SetPageChecked(page);
3780 return __set_page_dirty_nobuffers(page);
3783 static const struct address_space_operations ext4_ordered_aops = {
3784 .readpage = ext4_readpage,
3785 .readpages = ext4_readpages,
3786 .writepage = ext4_writepage,
3787 .sync_page = block_sync_page,
3788 .write_begin = ext4_write_begin,
3789 .write_end = ext4_ordered_write_end,
3791 .invalidatepage = ext4_invalidatepage,
3792 .releasepage = ext4_releasepage,
3793 .direct_IO = ext4_direct_IO,
3794 .migratepage = buffer_migrate_page,
3795 .is_partially_uptodate = block_is_partially_uptodate,
3796 .error_remove_page = generic_error_remove_page,
3799 static const struct address_space_operations ext4_writeback_aops = {
3800 .readpage = ext4_readpage,
3801 .readpages = ext4_readpages,
3802 .writepage = ext4_writepage,
3803 .sync_page = block_sync_page,
3804 .write_begin = ext4_write_begin,
3805 .write_end = ext4_writeback_write_end,
3807 .invalidatepage = ext4_invalidatepage,
3808 .releasepage = ext4_releasepage,
3809 .direct_IO = ext4_direct_IO,
3810 .migratepage = buffer_migrate_page,
3811 .is_partially_uptodate = block_is_partially_uptodate,
3812 .error_remove_page = generic_error_remove_page,
3815 static const struct address_space_operations ext4_journalled_aops = {
3816 .readpage = ext4_readpage,
3817 .readpages = ext4_readpages,
3818 .writepage = ext4_writepage,
3819 .sync_page = block_sync_page,
3820 .write_begin = ext4_write_begin,
3821 .write_end = ext4_journalled_write_end,
3822 .set_page_dirty = ext4_journalled_set_page_dirty,
3824 .invalidatepage = ext4_invalidatepage,
3825 .releasepage = ext4_releasepage,
3826 .is_partially_uptodate = block_is_partially_uptodate,
3827 .error_remove_page = generic_error_remove_page,
3830 static const struct address_space_operations ext4_da_aops = {
3831 .readpage = ext4_readpage,
3832 .readpages = ext4_readpages,
3833 .writepage = ext4_writepage,
3834 .writepages = ext4_da_writepages,
3835 .sync_page = block_sync_page,
3836 .write_begin = ext4_da_write_begin,
3837 .write_end = ext4_da_write_end,
3839 .invalidatepage = ext4_da_invalidatepage,
3840 .releasepage = ext4_releasepage,
3841 .direct_IO = ext4_direct_IO,
3842 .migratepage = buffer_migrate_page,
3843 .is_partially_uptodate = block_is_partially_uptodate,
3844 .error_remove_page = generic_error_remove_page,
3847 void ext4_set_aops(struct inode *inode)
3849 if (ext4_should_order_data(inode) &&
3850 test_opt(inode->i_sb, DELALLOC))
3851 inode->i_mapping->a_ops = &ext4_da_aops;
3852 else if (ext4_should_order_data(inode))
3853 inode->i_mapping->a_ops = &ext4_ordered_aops;
3854 else if (ext4_should_writeback_data(inode) &&
3855 test_opt(inode->i_sb, DELALLOC))
3856 inode->i_mapping->a_ops = &ext4_da_aops;
3857 else if (ext4_should_writeback_data(inode))
3858 inode->i_mapping->a_ops = &ext4_writeback_aops;
3860 inode->i_mapping->a_ops = &ext4_journalled_aops;
3864 * ext4_block_truncate_page() zeroes out a mapping from file offset `from'
3865 * up to the end of the block which corresponds to `from'.
3866 * This required during truncate. We need to physically zero the tail end
3867 * of that block so it doesn't yield old data if the file is later grown.
3869 int ext4_block_truncate_page(handle_t *handle,
3870 struct address_space *mapping, loff_t from)
3872 ext4_fsblk_t index = from >> PAGE_CACHE_SHIFT;
3873 unsigned offset = from & (PAGE_CACHE_SIZE-1);
3874 unsigned blocksize, length, pos;
3876 struct inode *inode = mapping->host;
3877 struct buffer_head *bh;
3881 page = find_or_create_page(mapping, from >> PAGE_CACHE_SHIFT,
3882 mapping_gfp_mask(mapping) & ~__GFP_FS);
3886 blocksize = inode->i_sb->s_blocksize;
3887 length = blocksize - (offset & (blocksize - 1));
3888 iblock = index << (PAGE_CACHE_SHIFT - inode->i_sb->s_blocksize_bits);
3891 * For "nobh" option, we can only work if we don't need to
3892 * read-in the page - otherwise we create buffers to do the IO.
3894 if (!page_has_buffers(page) && test_opt(inode->i_sb, NOBH) &&
3895 ext4_should_writeback_data(inode) && PageUptodate(page)) {
3896 zero_user(page, offset, length);
3897 set_page_dirty(page);
3901 if (!page_has_buffers(page))
3902 create_empty_buffers(page, blocksize, 0);
3904 /* Find the buffer that contains "offset" */
3905 bh = page_buffers(page);
3907 while (offset >= pos) {
3908 bh = bh->b_this_page;
3914 if (buffer_freed(bh)) {
3915 BUFFER_TRACE(bh, "freed: skip");
3919 if (!buffer_mapped(bh)) {
3920 BUFFER_TRACE(bh, "unmapped");
3921 ext4_get_block(inode, iblock, bh, 0);
3922 /* unmapped? It's a hole - nothing to do */
3923 if (!buffer_mapped(bh)) {
3924 BUFFER_TRACE(bh, "still unmapped");
3929 /* Ok, it's mapped. Make sure it's up-to-date */
3930 if (PageUptodate(page))
3931 set_buffer_uptodate(bh);
3933 if (!buffer_uptodate(bh)) {
3935 ll_rw_block(READ, 1, &bh);
3937 /* Uhhuh. Read error. Complain and punt. */
3938 if (!buffer_uptodate(bh))
3942 if (ext4_should_journal_data(inode)) {
3943 BUFFER_TRACE(bh, "get write access");
3944 err = ext4_journal_get_write_access(handle, bh);
3949 zero_user(page, offset, length);
3951 BUFFER_TRACE(bh, "zeroed end of block");
3954 if (ext4_should_journal_data(inode)) {
3955 err = ext4_handle_dirty_metadata(handle, inode, bh);
3957 if (ext4_should_order_data(inode))
3958 err = ext4_jbd2_file_inode(handle, inode);
3959 mark_buffer_dirty(bh);
3964 page_cache_release(page);
3969 * Probably it should be a library function... search for first non-zero word
3970 * or memcmp with zero_page, whatever is better for particular architecture.
3973 static inline int all_zeroes(__le32 *p, __le32 *q)
3982 * ext4_find_shared - find the indirect blocks for partial truncation.
3983 * @inode: inode in question
3984 * @depth: depth of the affected branch
3985 * @offsets: offsets of pointers in that branch (see ext4_block_to_path)
3986 * @chain: place to store the pointers to partial indirect blocks
3987 * @top: place to the (detached) top of branch
3989 * This is a helper function used by ext4_truncate().
3991 * When we do truncate() we may have to clean the ends of several
3992 * indirect blocks but leave the blocks themselves alive. Block is
3993 * partially truncated if some data below the new i_size is refered
3994 * from it (and it is on the path to the first completely truncated
3995 * data block, indeed). We have to free the top of that path along
3996 * with everything to the right of the path. Since no allocation
3997 * past the truncation point is possible until ext4_truncate()
3998 * finishes, we may safely do the latter, but top of branch may
3999 * require special attention - pageout below the truncation point
4000 * might try to populate it.
4002 * We atomically detach the top of branch from the tree, store the
4003 * block number of its root in *@top, pointers to buffer_heads of
4004 * partially truncated blocks - in @chain[].bh and pointers to
4005 * their last elements that should not be removed - in
4006 * @chain[].p. Return value is the pointer to last filled element
4009 * The work left to caller to do the actual freeing of subtrees:
4010 * a) free the subtree starting from *@top
4011 * b) free the subtrees whose roots are stored in
4012 * (@chain[i].p+1 .. end of @chain[i].bh->b_data)
4013 * c) free the subtrees growing from the inode past the @chain[0].
4014 * (no partially truncated stuff there). */
4016 static Indirect *ext4_find_shared(struct inode *inode, int depth,
4017 ext4_lblk_t offsets[4], Indirect chain[4],
4020 Indirect *partial, *p;
4024 /* Make k index the deepest non-null offest + 1 */
4025 for (k = depth; k > 1 && !offsets[k-1]; k--)
4027 partial = ext4_get_branch(inode, k, offsets, chain, &err);
4028 /* Writer: pointers */
4030 partial = chain + k-1;
4032 * If the branch acquired continuation since we've looked at it -
4033 * fine, it should all survive and (new) top doesn't belong to us.
4035 if (!partial->key && *partial->p)
4038 for (p = partial; (p > chain) && all_zeroes((__le32 *) p->bh->b_data, p->p); p--)
4041 * OK, we've found the last block that must survive. The rest of our
4042 * branch should be detached before unlocking. However, if that rest
4043 * of branch is all ours and does not grow immediately from the inode
4044 * it's easier to cheat and just decrement partial->p.
4046 if (p == chain + k - 1 && p > chain) {
4050 /* Nope, don't do this in ext4. Must leave the tree intact */
4057 while (partial > p) {
4058 brelse(partial->bh);
4066 * Zero a number of block pointers in either an inode or an indirect block.
4067 * If we restart the transaction we must again get write access to the
4068 * indirect block for further modification.
4070 * We release `count' blocks on disk, but (last - first) may be greater
4071 * than `count' because there can be holes in there.
4073 static void ext4_clear_blocks(handle_t *handle, struct inode *inode,
4074 struct buffer_head *bh,
4075 ext4_fsblk_t block_to_free,
4076 unsigned long count, __le32 *first,
4080 int flags = EXT4_FREE_BLOCKS_FORGET;
4082 if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode))
4083 flags |= EXT4_FREE_BLOCKS_METADATA;
4085 if (try_to_extend_transaction(handle, inode)) {
4087 BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
4088 ext4_handle_dirty_metadata(handle, inode, bh);
4090 ext4_mark_inode_dirty(handle, inode);
4091 ext4_truncate_restart_trans(handle, inode,
4092 blocks_for_truncate(inode));
4094 BUFFER_TRACE(bh, "retaking write access");
4095 ext4_journal_get_write_access(handle, bh);
4099 for (p = first; p < last; p++)
4102 ext4_free_blocks(handle, inode, 0, block_to_free, count, flags);
4106 * ext4_free_data - free a list of data blocks
4107 * @handle: handle for this transaction
4108 * @inode: inode we are dealing with
4109 * @this_bh: indirect buffer_head which contains *@first and *@last
4110 * @first: array of block numbers
4111 * @last: points immediately past the end of array
4113 * We are freeing all blocks refered from that array (numbers are stored as
4114 * little-endian 32-bit) and updating @inode->i_blocks appropriately.
4116 * We accumulate contiguous runs of blocks to free. Conveniently, if these
4117 * blocks are contiguous then releasing them at one time will only affect one
4118 * or two bitmap blocks (+ group descriptor(s) and superblock) and we won't
4119 * actually use a lot of journal space.
4121 * @this_bh will be %NULL if @first and @last point into the inode's direct
4124 static void ext4_free_data(handle_t *handle, struct inode *inode,
4125 struct buffer_head *this_bh,
4126 __le32 *first, __le32 *last)
4128 ext4_fsblk_t block_to_free = 0; /* Starting block # of a run */
4129 unsigned long count = 0; /* Number of blocks in the run */
4130 __le32 *block_to_free_p = NULL; /* Pointer into inode/ind
4133 ext4_fsblk_t nr; /* Current block # */
4134 __le32 *p; /* Pointer into inode/ind
4135 for current block */
4138 if (this_bh) { /* For indirect block */
4139 BUFFER_TRACE(this_bh, "get_write_access");
4140 err = ext4_journal_get_write_access(handle, this_bh);
4141 /* Important: if we can't update the indirect pointers
4142 * to the blocks, we can't free them. */
4147 for (p = first; p < last; p++) {
4148 nr = le32_to_cpu(*p);
4150 /* accumulate blocks to free if they're contiguous */
4153 block_to_free_p = p;
4155 } else if (nr == block_to_free + count) {
4158 ext4_clear_blocks(handle, inode, this_bh,
4160 count, block_to_free_p, p);
4162 block_to_free_p = p;
4169 ext4_clear_blocks(handle, inode, this_bh, block_to_free,
4170 count, block_to_free_p, p);
4173 BUFFER_TRACE(this_bh, "call ext4_handle_dirty_metadata");
4176 * The buffer head should have an attached journal head at this
4177 * point. However, if the data is corrupted and an indirect
4178 * block pointed to itself, it would have been detached when
4179 * the block was cleared. Check for this instead of OOPSing.
4181 if ((EXT4_JOURNAL(inode) == NULL) || bh2jh(this_bh))
4182 ext4_handle_dirty_metadata(handle, inode, this_bh);
4184 ext4_error(inode->i_sb, __func__,
4185 "circular indirect block detected, "
4186 "inode=%lu, block=%llu",
4188 (unsigned long long) this_bh->b_blocknr);
4193 * ext4_free_branches - free an array of branches
4194 * @handle: JBD handle for this transaction
4195 * @inode: inode we are dealing with
4196 * @parent_bh: the buffer_head which contains *@first and *@last
4197 * @first: array of block numbers
4198 * @last: pointer immediately past the end of array
4199 * @depth: depth of the branches to free
4201 * We are freeing all blocks refered from these branches (numbers are
4202 * stored as little-endian 32-bit) and updating @inode->i_blocks
4205 static void ext4_free_branches(handle_t *handle, struct inode *inode,
4206 struct buffer_head *parent_bh,
4207 __le32 *first, __le32 *last, int depth)
4212 if (ext4_handle_is_aborted(handle))
4216 struct buffer_head *bh;
4217 int addr_per_block = EXT4_ADDR_PER_BLOCK(inode->i_sb);
4219 while (--p >= first) {
4220 nr = le32_to_cpu(*p);
4222 continue; /* A hole */
4224 /* Go read the buffer for the next level down */
4225 bh = sb_bread(inode->i_sb, nr);
4228 * A read failure? Report error and clear slot
4232 ext4_error(inode->i_sb, "ext4_free_branches",
4233 "Read failure, inode=%lu, block=%llu",
4238 /* This zaps the entire block. Bottom up. */
4239 BUFFER_TRACE(bh, "free child branches");
4240 ext4_free_branches(handle, inode, bh,
4241 (__le32 *) bh->b_data,
4242 (__le32 *) bh->b_data + addr_per_block,
4246 * We've probably journalled the indirect block several
4247 * times during the truncate. But it's no longer
4248 * needed and we now drop it from the transaction via
4249 * jbd2_journal_revoke().
4251 * That's easy if it's exclusively part of this
4252 * transaction. But if it's part of the committing
4253 * transaction then jbd2_journal_forget() will simply
4254 * brelse() it. That means that if the underlying
4255 * block is reallocated in ext4_get_block(),
4256 * unmap_underlying_metadata() will find this block
4257 * and will try to get rid of it. damn, damn.
4259 * If this block has already been committed to the
4260 * journal, a revoke record will be written. And
4261 * revoke records must be emitted *before* clearing
4262 * this block's bit in the bitmaps.
4264 ext4_forget(handle, 1, inode, bh, bh->b_blocknr);
4267 * Everything below this this pointer has been
4268 * released. Now let this top-of-subtree go.
4270 * We want the freeing of this indirect block to be
4271 * atomic in the journal with the updating of the
4272 * bitmap block which owns it. So make some room in
4275 * We zero the parent pointer *after* freeing its
4276 * pointee in the bitmaps, so if extend_transaction()
4277 * for some reason fails to put the bitmap changes and
4278 * the release into the same transaction, recovery
4279 * will merely complain about releasing a free block,
4280 * rather than leaking blocks.
4282 if (ext4_handle_is_aborted(handle))
4284 if (try_to_extend_transaction(handle, inode)) {
4285 ext4_mark_inode_dirty(handle, inode);
4286 ext4_truncate_restart_trans(handle, inode,
4287 blocks_for_truncate(inode));
4290 ext4_free_blocks(handle, inode, 0, nr, 1,
4291 EXT4_FREE_BLOCKS_METADATA);
4295 * The block which we have just freed is
4296 * pointed to by an indirect block: journal it
4298 BUFFER_TRACE(parent_bh, "get_write_access");
4299 if (!ext4_journal_get_write_access(handle,
4302 BUFFER_TRACE(parent_bh,
4303 "call ext4_handle_dirty_metadata");
4304 ext4_handle_dirty_metadata(handle,
4311 /* We have reached the bottom of the tree. */
4312 BUFFER_TRACE(parent_bh, "free data blocks");
4313 ext4_free_data(handle, inode, parent_bh, first, last);
4317 int ext4_can_truncate(struct inode *inode)
4319 if (IS_APPEND(inode) || IS_IMMUTABLE(inode))
4321 if (S_ISREG(inode->i_mode))
4323 if (S_ISDIR(inode->i_mode))
4325 if (S_ISLNK(inode->i_mode))
4326 return !ext4_inode_is_fast_symlink(inode);
4333 * We block out ext4_get_block() block instantiations across the entire
4334 * transaction, and VFS/VM ensures that ext4_truncate() cannot run
4335 * simultaneously on behalf of the same inode.
4337 * As we work through the truncate and commmit bits of it to the journal there
4338 * is one core, guiding principle: the file's tree must always be consistent on
4339 * disk. We must be able to restart the truncate after a crash.
4341 * The file's tree may be transiently inconsistent in memory (although it
4342 * probably isn't), but whenever we close off and commit a journal transaction,
4343 * the contents of (the filesystem + the journal) must be consistent and
4344 * restartable. It's pretty simple, really: bottom up, right to left (although
4345 * left-to-right works OK too).
4347 * Note that at recovery time, journal replay occurs *before* the restart of
4348 * truncate against the orphan inode list.
4350 * The committed inode has the new, desired i_size (which is the same as
4351 * i_disksize in this case). After a crash, ext4_orphan_cleanup() will see
4352 * that this inode's truncate did not complete and it will again call
4353 * ext4_truncate() to have another go. So there will be instantiated blocks
4354 * to the right of the truncation point in a crashed ext4 filesystem. But
4355 * that's fine - as long as they are linked from the inode, the post-crash
4356 * ext4_truncate() run will find them and release them.
4358 void ext4_truncate(struct inode *inode)
4361 struct ext4_inode_info *ei = EXT4_I(inode);
4362 __le32 *i_data = ei->i_data;
4363 int addr_per_block = EXT4_ADDR_PER_BLOCK(inode->i_sb);
4364 struct address_space *mapping = inode->i_mapping;
4365 ext4_lblk_t offsets[4];
4370 ext4_lblk_t last_block;
4371 unsigned blocksize = inode->i_sb->s_blocksize;
4373 if (!ext4_can_truncate(inode))
4376 if (inode->i_size == 0 && !test_opt(inode->i_sb, NO_AUTO_DA_ALLOC))
4377 ei->i_state |= EXT4_STATE_DA_ALLOC_CLOSE;
4379 if (EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL) {
4380 ext4_ext_truncate(inode);
4384 handle = start_transaction(inode);
4386 return; /* AKPM: return what? */
4388 last_block = (inode->i_size + blocksize-1)
4389 >> EXT4_BLOCK_SIZE_BITS(inode->i_sb);
4391 if (inode->i_size & (blocksize - 1))
4392 if (ext4_block_truncate_page(handle, mapping, inode->i_size))
4395 n = ext4_block_to_path(inode, last_block, offsets, NULL);
4397 goto out_stop; /* error */
4400 * OK. This truncate is going to happen. We add the inode to the
4401 * orphan list, so that if this truncate spans multiple transactions,
4402 * and we crash, we will resume the truncate when the filesystem
4403 * recovers. It also marks the inode dirty, to catch the new size.
4405 * Implication: the file must always be in a sane, consistent
4406 * truncatable state while each transaction commits.
4408 if (ext4_orphan_add(handle, inode))
4412 * From here we block out all ext4_get_block() callers who want to
4413 * modify the block allocation tree.
4415 down_write(&ei->i_data_sem);
4417 ext4_discard_preallocations(inode);
4420 * The orphan list entry will now protect us from any crash which
4421 * occurs before the truncate completes, so it is now safe to propagate
4422 * the new, shorter inode size (held for now in i_size) into the
4423 * on-disk inode. We do this via i_disksize, which is the value which
4424 * ext4 *really* writes onto the disk inode.
4426 ei->i_disksize = inode->i_size;
4428 if (n == 1) { /* direct blocks */
4429 ext4_free_data(handle, inode, NULL, i_data+offsets[0],
4430 i_data + EXT4_NDIR_BLOCKS);
4434 partial = ext4_find_shared(inode, n, offsets, chain, &nr);
4435 /* Kill the top of shared branch (not detached) */
4437 if (partial == chain) {
4438 /* Shared branch grows from the inode */
4439 ext4_free_branches(handle, inode, NULL,
4440 &nr, &nr+1, (chain+n-1) - partial);
4443 * We mark the inode dirty prior to restart,
4444 * and prior to stop. No need for it here.
4447 /* Shared branch grows from an indirect block */
4448 BUFFER_TRACE(partial->bh, "get_write_access");
4449 ext4_free_branches(handle, inode, partial->bh,
4451 partial->p+1, (chain+n-1) - partial);
4454 /* Clear the ends of indirect blocks on the shared branch */
4455 while (partial > chain) {
4456 ext4_free_branches(handle, inode, partial->bh, partial->p + 1,
4457 (__le32*)partial->bh->b_data+addr_per_block,
4458 (chain+n-1) - partial);
4459 BUFFER_TRACE(partial->bh, "call brelse");
4460 brelse(partial->bh);
4464 /* Kill the remaining (whole) subtrees */
4465 switch (offsets[0]) {
4467 nr = i_data[EXT4_IND_BLOCK];
4469 ext4_free_branches(handle, inode, NULL, &nr, &nr+1, 1);
4470 i_data[EXT4_IND_BLOCK] = 0;
4472 case EXT4_IND_BLOCK:
4473 nr = i_data[EXT4_DIND_BLOCK];
4475 ext4_free_branches(handle, inode, NULL, &nr, &nr+1, 2);
4476 i_data[EXT4_DIND_BLOCK] = 0;
4478 case EXT4_DIND_BLOCK:
4479 nr = i_data[EXT4_TIND_BLOCK];
4481 ext4_free_branches(handle, inode, NULL, &nr, &nr+1, 3);
4482 i_data[EXT4_TIND_BLOCK] = 0;
4484 case EXT4_TIND_BLOCK:
4488 up_write(&ei->i_data_sem);
4489 inode->i_mtime = inode->i_ctime = ext4_current_time(inode);
4490 ext4_mark_inode_dirty(handle, inode);
4493 * In a multi-transaction truncate, we only make the final transaction
4497 ext4_handle_sync(handle);
4500 * If this was a simple ftruncate(), and the file will remain alive
4501 * then we need to clear up the orphan record which we created above.
4502 * However, if this was a real unlink then we were called by
4503 * ext4_delete_inode(), and we allow that function to clean up the
4504 * orphan info for us.
4507 ext4_orphan_del(handle, inode);
4509 ext4_journal_stop(handle);
4513 * ext4_get_inode_loc returns with an extra refcount against the inode's
4514 * underlying buffer_head on success. If 'in_mem' is true, we have all
4515 * data in memory that is needed to recreate the on-disk version of this
4518 static int __ext4_get_inode_loc(struct inode *inode,
4519 struct ext4_iloc *iloc, int in_mem)
4521 struct ext4_group_desc *gdp;
4522 struct buffer_head *bh;
4523 struct super_block *sb = inode->i_sb;
4525 int inodes_per_block, inode_offset;
4528 if (!ext4_valid_inum(sb, inode->i_ino))
4531 iloc->block_group = (inode->i_ino - 1) / EXT4_INODES_PER_GROUP(sb);
4532 gdp = ext4_get_group_desc(sb, iloc->block_group, NULL);
4537 * Figure out the offset within the block group inode table
4539 inodes_per_block = (EXT4_BLOCK_SIZE(sb) / EXT4_INODE_SIZE(sb));
4540 inode_offset = ((inode->i_ino - 1) %
4541 EXT4_INODES_PER_GROUP(sb));
4542 block = ext4_inode_table(sb, gdp) + (inode_offset / inodes_per_block);
4543 iloc->offset = (inode_offset % inodes_per_block) * EXT4_INODE_SIZE(sb);
4545 bh = sb_getblk(sb, block);
4547 ext4_error(sb, "ext4_get_inode_loc", "unable to read "
4548 "inode block - inode=%lu, block=%llu",
4549 inode->i_ino, block);
4552 if (!buffer_uptodate(bh)) {
4556 * If the buffer has the write error flag, we have failed
4557 * to write out another inode in the same block. In this
4558 * case, we don't have to read the block because we may
4559 * read the old inode data successfully.
4561 if (buffer_write_io_error(bh) && !buffer_uptodate(bh))
4562 set_buffer_uptodate(bh);
4564 if (buffer_uptodate(bh)) {
4565 /* someone brought it uptodate while we waited */
4571 * If we have all information of the inode in memory and this
4572 * is the only valid inode in the block, we need not read the
4576 struct buffer_head *bitmap_bh;
4579 start = inode_offset & ~(inodes_per_block - 1);
4581 /* Is the inode bitmap in cache? */
4582 bitmap_bh = sb_getblk(sb, ext4_inode_bitmap(sb, gdp));
4587 * If the inode bitmap isn't in cache then the
4588 * optimisation may end up performing two reads instead
4589 * of one, so skip it.
4591 if (!buffer_uptodate(bitmap_bh)) {
4595 for (i = start; i < start + inodes_per_block; i++) {
4596 if (i == inode_offset)
4598 if (ext4_test_bit(i, bitmap_bh->b_data))
4602 if (i == start + inodes_per_block) {
4603 /* all other inodes are free, so skip I/O */
4604 memset(bh->b_data, 0, bh->b_size);
4605 set_buffer_uptodate(bh);
4613 * If we need to do any I/O, try to pre-readahead extra
4614 * blocks from the inode table.
4616 if (EXT4_SB(sb)->s_inode_readahead_blks) {
4617 ext4_fsblk_t b, end, table;
4620 table = ext4_inode_table(sb, gdp);
4621 /* s_inode_readahead_blks is always a power of 2 */
4622 b = block & ~(EXT4_SB(sb)->s_inode_readahead_blks-1);
4625 end = b + EXT4_SB(sb)->s_inode_readahead_blks;
4626 num = EXT4_INODES_PER_GROUP(sb);
4627 if (EXT4_HAS_RO_COMPAT_FEATURE(sb,
4628 EXT4_FEATURE_RO_COMPAT_GDT_CSUM))
4629 num -= ext4_itable_unused_count(sb, gdp);
4630 table += num / inodes_per_block;
4634 sb_breadahead(sb, b++);
4638 * There are other valid inodes in the buffer, this inode
4639 * has in-inode xattrs, or we don't have this inode in memory.
4640 * Read the block from disk.
4643 bh->b_end_io = end_buffer_read_sync;
4644 submit_bh(READ_META, bh);
4646 if (!buffer_uptodate(bh)) {
4647 ext4_error(sb, __func__,
4648 "unable to read inode block - inode=%lu, "
4649 "block=%llu", inode->i_ino, block);
4659 int ext4_get_inode_loc(struct inode *inode, struct ext4_iloc *iloc)
4661 /* We have all inode data except xattrs in memory here. */
4662 return __ext4_get_inode_loc(inode, iloc,
4663 !(EXT4_I(inode)->i_state & EXT4_STATE_XATTR));
4666 void ext4_set_inode_flags(struct inode *inode)
4668 unsigned int flags = EXT4_I(inode)->i_flags;
4670 inode->i_flags &= ~(S_SYNC|S_APPEND|S_IMMUTABLE|S_NOATIME|S_DIRSYNC);
4671 if (flags & EXT4_SYNC_FL)
4672 inode->i_flags |= S_SYNC;
4673 if (flags & EXT4_APPEND_FL)
4674 inode->i_flags |= S_APPEND;
4675 if (flags & EXT4_IMMUTABLE_FL)
4676 inode->i_flags |= S_IMMUTABLE;
4677 if (flags & EXT4_NOATIME_FL)
4678 inode->i_flags |= S_NOATIME;
4679 if (flags & EXT4_DIRSYNC_FL)
4680 inode->i_flags |= S_DIRSYNC;
4683 /* Propagate flags from i_flags to EXT4_I(inode)->i_flags */
4684 void ext4_get_inode_flags(struct ext4_inode_info *ei)
4686 unsigned int flags = ei->vfs_inode.i_flags;
4688 ei->i_flags &= ~(EXT4_SYNC_FL|EXT4_APPEND_FL|
4689 EXT4_IMMUTABLE_FL|EXT4_NOATIME_FL|EXT4_DIRSYNC_FL);
4691 ei->i_flags |= EXT4_SYNC_FL;
4692 if (flags & S_APPEND)
4693 ei->i_flags |= EXT4_APPEND_FL;
4694 if (flags & S_IMMUTABLE)
4695 ei->i_flags |= EXT4_IMMUTABLE_FL;
4696 if (flags & S_NOATIME)
4697 ei->i_flags |= EXT4_NOATIME_FL;
4698 if (flags & S_DIRSYNC)
4699 ei->i_flags |= EXT4_DIRSYNC_FL;
4702 static blkcnt_t ext4_inode_blocks(struct ext4_inode *raw_inode,
4703 struct ext4_inode_info *ei)
4706 struct inode *inode = &(ei->vfs_inode);
4707 struct super_block *sb = inode->i_sb;
4709 if (EXT4_HAS_RO_COMPAT_FEATURE(sb,
4710 EXT4_FEATURE_RO_COMPAT_HUGE_FILE)) {
4711 /* we are using combined 48 bit field */
4712 i_blocks = ((u64)le16_to_cpu(raw_inode->i_blocks_high)) << 32 |
4713 le32_to_cpu(raw_inode->i_blocks_lo);
4714 if (ei->i_flags & EXT4_HUGE_FILE_FL) {
4715 /* i_blocks represent file system block size */
4716 return i_blocks << (inode->i_blkbits - 9);
4721 return le32_to_cpu(raw_inode->i_blocks_lo);
4725 struct inode *ext4_iget(struct super_block *sb, unsigned long ino)
4727 struct ext4_iloc iloc;
4728 struct ext4_inode *raw_inode;
4729 struct ext4_inode_info *ei;
4730 struct inode *inode;
4734 inode = iget_locked(sb, ino);
4736 return ERR_PTR(-ENOMEM);
4737 if (!(inode->i_state & I_NEW))
4743 ret = __ext4_get_inode_loc(inode, &iloc, 0);
4746 raw_inode = ext4_raw_inode(&iloc);
4747 inode->i_mode = le16_to_cpu(raw_inode->i_mode);
4748 inode->i_uid = (uid_t)le16_to_cpu(raw_inode->i_uid_low);
4749 inode->i_gid = (gid_t)le16_to_cpu(raw_inode->i_gid_low);
4750 if (!(test_opt(inode->i_sb, NO_UID32))) {
4751 inode->i_uid |= le16_to_cpu(raw_inode->i_uid_high) << 16;
4752 inode->i_gid |= le16_to_cpu(raw_inode->i_gid_high) << 16;
4754 inode->i_nlink = le16_to_cpu(raw_inode->i_links_count);
4757 ei->i_dir_start_lookup = 0;
4758 ei->i_dtime = le32_to_cpu(raw_inode->i_dtime);
4759 /* We now have enough fields to check if the inode was active or not.
4760 * This is needed because nfsd might try to access dead inodes
4761 * the test is that same one that e2fsck uses
4762 * NeilBrown 1999oct15
4764 if (inode->i_nlink == 0) {
4765 if (inode->i_mode == 0 ||
4766 !(EXT4_SB(inode->i_sb)->s_mount_state & EXT4_ORPHAN_FS)) {
4767 /* this inode is deleted */
4771 /* The only unlinked inodes we let through here have
4772 * valid i_mode and are being read by the orphan
4773 * recovery code: that's fine, we're about to complete
4774 * the process of deleting those. */
4776 ei->i_flags = le32_to_cpu(raw_inode->i_flags);
4777 inode->i_blocks = ext4_inode_blocks(raw_inode, ei);
4778 ei->i_file_acl = le32_to_cpu(raw_inode->i_file_acl_lo);
4779 if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_64BIT))
4781 ((__u64)le16_to_cpu(raw_inode->i_file_acl_high)) << 32;
4782 inode->i_size = ext4_isize(raw_inode);
4783 ei->i_disksize = inode->i_size;
4784 inode->i_generation = le32_to_cpu(raw_inode->i_generation);
4785 ei->i_block_group = iloc.block_group;
4786 ei->i_last_alloc_group = ~0;
4788 * NOTE! The in-memory inode i_data array is in little-endian order
4789 * even on big-endian machines: we do NOT byteswap the block numbers!
4791 for (block = 0; block < EXT4_N_BLOCKS; block++)
4792 ei->i_data[block] = raw_inode->i_block[block];
4793 INIT_LIST_HEAD(&ei->i_orphan);
4795 if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE) {
4796 ei->i_extra_isize = le16_to_cpu(raw_inode->i_extra_isize);
4797 if (EXT4_GOOD_OLD_INODE_SIZE + ei->i_extra_isize >
4798 EXT4_INODE_SIZE(inode->i_sb)) {
4802 if (ei->i_extra_isize == 0) {
4803 /* The extra space is currently unused. Use it. */
4804 ei->i_extra_isize = sizeof(struct ext4_inode) -
4805 EXT4_GOOD_OLD_INODE_SIZE;
4807 __le32 *magic = (void *)raw_inode +
4808 EXT4_GOOD_OLD_INODE_SIZE +
4810 if (*magic == cpu_to_le32(EXT4_XATTR_MAGIC))
4811 ei->i_state |= EXT4_STATE_XATTR;
4814 ei->i_extra_isize = 0;
4816 EXT4_INODE_GET_XTIME(i_ctime, inode, raw_inode);
4817 EXT4_INODE_GET_XTIME(i_mtime, inode, raw_inode);
4818 EXT4_INODE_GET_XTIME(i_atime, inode, raw_inode);
4819 EXT4_EINODE_GET_XTIME(i_crtime, ei, raw_inode);
4821 inode->i_version = le32_to_cpu(raw_inode->i_disk_version);
4822 if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE) {
4823 if (EXT4_FITS_IN_INODE(raw_inode, ei, i_version_hi))
4825 (__u64)(le32_to_cpu(raw_inode->i_version_hi)) << 32;
4829 if (ei->i_file_acl &&
4830 !ext4_data_block_valid(EXT4_SB(sb), ei->i_file_acl, 1)) {
4831 ext4_error(sb, __func__,
4832 "bad extended attribute block %llu in inode #%lu",
4833 ei->i_file_acl, inode->i_ino);
4836 } else if (ei->i_flags & EXT4_EXTENTS_FL) {
4837 if (S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
4838 (S_ISLNK(inode->i_mode) &&
4839 !ext4_inode_is_fast_symlink(inode)))
4840 /* Validate extent which is part of inode */
4841 ret = ext4_ext_check_inode(inode);
4842 } else if (S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
4843 (S_ISLNK(inode->i_mode) &&
4844 !ext4_inode_is_fast_symlink(inode))) {
4845 /* Validate block references which are part of inode */
4846 ret = ext4_check_inode_blockref(inode);
4851 if (S_ISREG(inode->i_mode)) {
4852 inode->i_op = &ext4_file_inode_operations;
4853 inode->i_fop = &ext4_file_operations;
4854 ext4_set_aops(inode);
4855 } else if (S_ISDIR(inode->i_mode)) {
4856 inode->i_op = &ext4_dir_inode_operations;
4857 inode->i_fop = &ext4_dir_operations;
4858 } else if (S_ISLNK(inode->i_mode)) {
4859 if (ext4_inode_is_fast_symlink(inode)) {
4860 inode->i_op = &ext4_fast_symlink_inode_operations;
4861 nd_terminate_link(ei->i_data, inode->i_size,
4862 sizeof(ei->i_data) - 1);
4864 inode->i_op = &ext4_symlink_inode_operations;
4865 ext4_set_aops(inode);
4867 } else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode) ||
4868 S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode)) {
4869 inode->i_op = &ext4_special_inode_operations;
4870 if (raw_inode->i_block[0])
4871 init_special_inode(inode, inode->i_mode,
4872 old_decode_dev(le32_to_cpu(raw_inode->i_block[0])));
4874 init_special_inode(inode, inode->i_mode,
4875 new_decode_dev(le32_to_cpu(raw_inode->i_block[1])));
4878 ext4_error(inode->i_sb, __func__,
4879 "bogus i_mode (%o) for inode=%lu",
4880 inode->i_mode, inode->i_ino);
4884 ext4_set_inode_flags(inode);
4885 unlock_new_inode(inode);
4891 return ERR_PTR(ret);
4894 static int ext4_inode_blocks_set(handle_t *handle,
4895 struct ext4_inode *raw_inode,
4896 struct ext4_inode_info *ei)
4898 struct inode *inode = &(ei->vfs_inode);
4899 u64 i_blocks = inode->i_blocks;
4900 struct super_block *sb = inode->i_sb;
4902 if (i_blocks <= ~0U) {
4904 * i_blocks can be represnted in a 32 bit variable
4905 * as multiple of 512 bytes
4907 raw_inode->i_blocks_lo = cpu_to_le32(i_blocks);
4908 raw_inode->i_blocks_high = 0;
4909 ei->i_flags &= ~EXT4_HUGE_FILE_FL;
4912 if (!EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_HUGE_FILE))
4915 if (i_blocks <= 0xffffffffffffULL) {
4917 * i_blocks can be represented in a 48 bit variable
4918 * as multiple of 512 bytes
4920 raw_inode->i_blocks_lo = cpu_to_le32(i_blocks);
4921 raw_inode->i_blocks_high = cpu_to_le16(i_blocks >> 32);
4922 ei->i_flags &= ~EXT4_HUGE_FILE_FL;
4924 ei->i_flags |= EXT4_HUGE_FILE_FL;
4925 /* i_block is stored in file system block size */
4926 i_blocks = i_blocks >> (inode->i_blkbits - 9);
4927 raw_inode->i_blocks_lo = cpu_to_le32(i_blocks);
4928 raw_inode->i_blocks_high = cpu_to_le16(i_blocks >> 32);
4934 * Post the struct inode info into an on-disk inode location in the
4935 * buffer-cache. This gobbles the caller's reference to the
4936 * buffer_head in the inode location struct.
4938 * The caller must have write access to iloc->bh.
4940 static int ext4_do_update_inode(handle_t *handle,
4941 struct inode *inode,
4942 struct ext4_iloc *iloc)
4944 struct ext4_inode *raw_inode = ext4_raw_inode(iloc);
4945 struct ext4_inode_info *ei = EXT4_I(inode);
4946 struct buffer_head *bh = iloc->bh;
4947 int err = 0, rc, block;
4949 /* For fields not not tracking in the in-memory inode,
4950 * initialise them to zero for new inodes. */
4951 if (ei->i_state & EXT4_STATE_NEW)
4952 memset(raw_inode, 0, EXT4_SB(inode->i_sb)->s_inode_size);
4954 ext4_get_inode_flags(ei);
4955 raw_inode->i_mode = cpu_to_le16(inode->i_mode);
4956 if (!(test_opt(inode->i_sb, NO_UID32))) {
4957 raw_inode->i_uid_low = cpu_to_le16(low_16_bits(inode->i_uid));
4958 raw_inode->i_gid_low = cpu_to_le16(low_16_bits(inode->i_gid));
4960 * Fix up interoperability with old kernels. Otherwise, old inodes get
4961 * re-used with the upper 16 bits of the uid/gid intact
4964 raw_inode->i_uid_high =
4965 cpu_to_le16(high_16_bits(inode->i_uid));
4966 raw_inode->i_gid_high =
4967 cpu_to_le16(high_16_bits(inode->i_gid));
4969 raw_inode->i_uid_high = 0;
4970 raw_inode->i_gid_high = 0;
4973 raw_inode->i_uid_low =
4974 cpu_to_le16(fs_high2lowuid(inode->i_uid));
4975 raw_inode->i_gid_low =
4976 cpu_to_le16(fs_high2lowgid(inode->i_gid));
4977 raw_inode->i_uid_high = 0;
4978 raw_inode->i_gid_high = 0;
4980 raw_inode->i_links_count = cpu_to_le16(inode->i_nlink);
4982 EXT4_INODE_SET_XTIME(i_ctime, inode, raw_inode);
4983 EXT4_INODE_SET_XTIME(i_mtime, inode, raw_inode);
4984 EXT4_INODE_SET_XTIME(i_atime, inode, raw_inode);
4985 EXT4_EINODE_SET_XTIME(i_crtime, ei, raw_inode);
4987 if (ext4_inode_blocks_set(handle, raw_inode, ei))
4989 raw_inode->i_dtime = cpu_to_le32(ei->i_dtime);
4990 raw_inode->i_flags = cpu_to_le32(ei->i_flags);
4991 if (EXT4_SB(inode->i_sb)->s_es->s_creator_os !=
4992 cpu_to_le32(EXT4_OS_HURD))
4993 raw_inode->i_file_acl_high =
4994 cpu_to_le16(ei->i_file_acl >> 32);
4995 raw_inode->i_file_acl_lo = cpu_to_le32(ei->i_file_acl);
4996 ext4_isize_set(raw_inode, ei->i_disksize);
4997 if (ei->i_disksize > 0x7fffffffULL) {
4998 struct super_block *sb = inode->i_sb;
4999 if (!EXT4_HAS_RO_COMPAT_FEATURE(sb,
5000 EXT4_FEATURE_RO_COMPAT_LARGE_FILE) ||
5001 EXT4_SB(sb)->s_es->s_rev_level ==
5002 cpu_to_le32(EXT4_GOOD_OLD_REV)) {
5003 /* If this is the first large file
5004 * created, add a flag to the superblock.
5006 err = ext4_journal_get_write_access(handle,
5007 EXT4_SB(sb)->s_sbh);
5010 ext4_update_dynamic_rev(sb);
5011 EXT4_SET_RO_COMPAT_FEATURE(sb,
5012 EXT4_FEATURE_RO_COMPAT_LARGE_FILE);
5014 ext4_handle_sync(handle);
5015 err = ext4_handle_dirty_metadata(handle, inode,
5016 EXT4_SB(sb)->s_sbh);
5019 raw_inode->i_generation = cpu_to_le32(inode->i_generation);
5020 if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode)) {
5021 if (old_valid_dev(inode->i_rdev)) {
5022 raw_inode->i_block[0] =
5023 cpu_to_le32(old_encode_dev(inode->i_rdev));
5024 raw_inode->i_block[1] = 0;
5026 raw_inode->i_block[0] = 0;
5027 raw_inode->i_block[1] =
5028 cpu_to_le32(new_encode_dev(inode->i_rdev));
5029 raw_inode->i_block[2] = 0;
5032 for (block = 0; block < EXT4_N_BLOCKS; block++)
5033 raw_inode->i_block[block] = ei->i_data[block];
5035 raw_inode->i_disk_version = cpu_to_le32(inode->i_version);
5036 if (ei->i_extra_isize) {
5037 if (EXT4_FITS_IN_INODE(raw_inode, ei, i_version_hi))
5038 raw_inode->i_version_hi =
5039 cpu_to_le32(inode->i_version >> 32);
5040 raw_inode->i_extra_isize = cpu_to_le16(ei->i_extra_isize);
5043 BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
5044 rc = ext4_handle_dirty_metadata(handle, inode, bh);
5047 ei->i_state &= ~EXT4_STATE_NEW;
5051 ext4_std_error(inode->i_sb, err);
5056 * ext4_write_inode()
5058 * We are called from a few places:
5060 * - Within generic_file_write() for O_SYNC files.
5061 * Here, there will be no transaction running. We wait for any running
5062 * trasnaction to commit.
5064 * - Within sys_sync(), kupdate and such.
5065 * We wait on commit, if tol to.
5067 * - Within prune_icache() (PF_MEMALLOC == true)
5068 * Here we simply return. We can't afford to block kswapd on the
5071 * In all cases it is actually safe for us to return without doing anything,
5072 * because the inode has been copied into a raw inode buffer in
5073 * ext4_mark_inode_dirty(). This is a correctness thing for O_SYNC and for
5076 * Note that we are absolutely dependent upon all inode dirtiers doing the
5077 * right thing: they *must* call mark_inode_dirty() after dirtying info in
5078 * which we are interested.
5080 * It would be a bug for them to not do this. The code:
5082 * mark_inode_dirty(inode)
5084 * inode->i_size = expr;
5086 * is in error because a kswapd-driven write_inode() could occur while
5087 * `stuff()' is running, and the new i_size will be lost. Plus the inode
5088 * will no longer be on the superblock's dirty inode list.
5090 int ext4_write_inode(struct inode *inode, int wait)
5094 if (current->flags & PF_MEMALLOC)
5097 if (EXT4_SB(inode->i_sb)->s_journal) {
5098 if (ext4_journal_current_handle()) {
5099 jbd_debug(1, "called recursively, non-PF_MEMALLOC!\n");
5107 err = ext4_force_commit(inode->i_sb);
5109 struct ext4_iloc iloc;
5111 err = ext4_get_inode_loc(inode, &iloc);
5115 sync_dirty_buffer(iloc.bh);
5116 if (buffer_req(iloc.bh) && !buffer_uptodate(iloc.bh)) {
5117 ext4_error(inode->i_sb, __func__,
5118 "IO error syncing inode, "
5119 "inode=%lu, block=%llu",
5121 (unsigned long long)iloc.bh->b_blocknr);
5131 * Called from notify_change.
5133 * We want to trap VFS attempts to truncate the file as soon as
5134 * possible. In particular, we want to make sure that when the VFS
5135 * shrinks i_size, we put the inode on the orphan list and modify
5136 * i_disksize immediately, so that during the subsequent flushing of
5137 * dirty pages and freeing of disk blocks, we can guarantee that any
5138 * commit will leave the blocks being flushed in an unused state on
5139 * disk. (On recovery, the inode will get truncated and the blocks will
5140 * be freed, so we have a strong guarantee that no future commit will
5141 * leave these blocks visible to the user.)
5143 * Another thing we have to assure is that if we are in ordered mode
5144 * and inode is still attached to the committing transaction, we must
5145 * we start writeout of all the dirty pages which are being truncated.
5146 * This way we are sure that all the data written in the previous
5147 * transaction are already on disk (truncate waits for pages under
5150 * Called with inode->i_mutex down.
5152 int ext4_setattr(struct dentry *dentry, struct iattr *attr)
5154 struct inode *inode = dentry->d_inode;
5156 const unsigned int ia_valid = attr->ia_valid;
5158 error = inode_change_ok(inode, attr);
5162 if ((ia_valid & ATTR_UID && attr->ia_uid != inode->i_uid) ||
5163 (ia_valid & ATTR_GID && attr->ia_gid != inode->i_gid)) {
5166 /* (user+group)*(old+new) structure, inode write (sb,
5167 * inode block, ? - but truncate inode update has it) */
5168 handle = ext4_journal_start(inode, 2*(EXT4_QUOTA_INIT_BLOCKS(inode->i_sb)+
5169 EXT4_QUOTA_DEL_BLOCKS(inode->i_sb))+3);
5170 if (IS_ERR(handle)) {
5171 error = PTR_ERR(handle);
5174 error = vfs_dq_transfer(inode, attr) ? -EDQUOT : 0;
5176 ext4_journal_stop(handle);
5179 /* Update corresponding info in inode so that everything is in
5180 * one transaction */
5181 if (attr->ia_valid & ATTR_UID)
5182 inode->i_uid = attr->ia_uid;
5183 if (attr->ia_valid & ATTR_GID)
5184 inode->i_gid = attr->ia_gid;
5185 error = ext4_mark_inode_dirty(handle, inode);
5186 ext4_journal_stop(handle);
5189 if (attr->ia_valid & ATTR_SIZE) {
5190 if (!(EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL)) {
5191 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
5193 if (attr->ia_size > sbi->s_bitmap_maxbytes) {
5200 if (S_ISREG(inode->i_mode) &&
5201 attr->ia_valid & ATTR_SIZE && attr->ia_size < inode->i_size) {
5204 handle = ext4_journal_start(inode, 3);
5205 if (IS_ERR(handle)) {
5206 error = PTR_ERR(handle);
5210 error = ext4_orphan_add(handle, inode);
5211 EXT4_I(inode)->i_disksize = attr->ia_size;
5212 rc = ext4_mark_inode_dirty(handle, inode);
5215 ext4_journal_stop(handle);
5217 if (ext4_should_order_data(inode)) {
5218 error = ext4_begin_ordered_truncate(inode,
5221 /* Do as much error cleanup as possible */
5222 handle = ext4_journal_start(inode, 3);
5223 if (IS_ERR(handle)) {
5224 ext4_orphan_del(NULL, inode);
5227 ext4_orphan_del(handle, inode);
5228 ext4_journal_stop(handle);
5234 rc = inode_setattr(inode, attr);
5236 /* If inode_setattr's call to ext4_truncate failed to get a
5237 * transaction handle at all, we need to clean up the in-core
5238 * orphan list manually. */
5240 ext4_orphan_del(NULL, inode);
5242 if (!rc && (ia_valid & ATTR_MODE))
5243 rc = ext4_acl_chmod(inode);
5246 ext4_std_error(inode->i_sb, error);
5252 int ext4_getattr(struct vfsmount *mnt, struct dentry *dentry,
5255 struct inode *inode;
5256 unsigned long delalloc_blocks;
5258 inode = dentry->d_inode;
5259 generic_fillattr(inode, stat);
5262 * We can't update i_blocks if the block allocation is delayed
5263 * otherwise in the case of system crash before the real block
5264 * allocation is done, we will have i_blocks inconsistent with
5265 * on-disk file blocks.
5266 * We always keep i_blocks updated together with real
5267 * allocation. But to not confuse with user, stat
5268 * will return the blocks that include the delayed allocation
5269 * blocks for this file.
5271 spin_lock(&EXT4_I(inode)->i_block_reservation_lock);
5272 delalloc_blocks = EXT4_I(inode)->i_reserved_data_blocks;
5273 spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
5275 stat->blocks += (delalloc_blocks << inode->i_sb->s_blocksize_bits)>>9;
5279 static int ext4_indirect_trans_blocks(struct inode *inode, int nrblocks,
5284 /* if nrblocks are contiguous */
5287 * With N contiguous data blocks, it need at most
5288 * N/EXT4_ADDR_PER_BLOCK(inode->i_sb) indirect blocks
5289 * 2 dindirect blocks
5292 indirects = nrblocks / EXT4_ADDR_PER_BLOCK(inode->i_sb);
5293 return indirects + 3;
5296 * if nrblocks are not contiguous, worse case, each block touch
5297 * a indirect block, and each indirect block touch a double indirect
5298 * block, plus a triple indirect block
5300 indirects = nrblocks * 2 + 1;
5304 static int ext4_index_trans_blocks(struct inode *inode, int nrblocks, int chunk)
5306 if (!(EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL))
5307 return ext4_indirect_trans_blocks(inode, nrblocks, chunk);
5308 return ext4_ext_index_trans_blocks(inode, nrblocks, chunk);
5312 * Account for index blocks, block groups bitmaps and block group
5313 * descriptor blocks if modify datablocks and index blocks
5314 * worse case, the indexs blocks spread over different block groups
5316 * If datablocks are discontiguous, they are possible to spread over
5317 * different block groups too. If they are contiugous, with flexbg,
5318 * they could still across block group boundary.
5320 * Also account for superblock, inode, quota and xattr blocks
5322 int ext4_meta_trans_blocks(struct inode *inode, int nrblocks, int chunk)
5324 ext4_group_t groups, ngroups = ext4_get_groups_count(inode->i_sb);
5330 * How many index blocks need to touch to modify nrblocks?
5331 * The "Chunk" flag indicating whether the nrblocks is
5332 * physically contiguous on disk
5334 * For Direct IO and fallocate, they calls get_block to allocate
5335 * one single extent at a time, so they could set the "Chunk" flag
5337 idxblocks = ext4_index_trans_blocks(inode, nrblocks, chunk);
5342 * Now let's see how many group bitmaps and group descriptors need
5352 if (groups > ngroups)
5354 if (groups > EXT4_SB(inode->i_sb)->s_gdb_count)
5355 gdpblocks = EXT4_SB(inode->i_sb)->s_gdb_count;
5357 /* bitmaps and block group descriptor blocks */
5358 ret += groups + gdpblocks;
5360 /* Blocks for super block, inode, quota and xattr blocks */
5361 ret += EXT4_META_TRANS_BLOCKS(inode->i_sb);
5367 * Calulate the total number of credits to reserve to fit
5368 * the modification of a single pages into a single transaction,
5369 * which may include multiple chunks of block allocations.
5371 * This could be called via ext4_write_begin()
5373 * We need to consider the worse case, when
5374 * one new block per extent.
5376 int ext4_writepage_trans_blocks(struct inode *inode)
5378 int bpp = ext4_journal_blocks_per_page(inode);
5381 ret = ext4_meta_trans_blocks(inode, bpp, 0);
5383 /* Account for data blocks for journalled mode */
5384 if (ext4_should_journal_data(inode))
5390 * Calculate the journal credits for a chunk of data modification.
5392 * This is called from DIO, fallocate or whoever calling
5393 * ext4_get_blocks() to map/allocate a chunk of contigous disk blocks.
5395 * journal buffers for data blocks are not included here, as DIO
5396 * and fallocate do no need to journal data buffers.
5398 int ext4_chunk_trans_blocks(struct inode *inode, int nrblocks)
5400 return ext4_meta_trans_blocks(inode, nrblocks, 1);
5404 * The caller must have previously called ext4_reserve_inode_write().
5405 * Give this, we know that the caller already has write access to iloc->bh.
5407 int ext4_mark_iloc_dirty(handle_t *handle,
5408 struct inode *inode, struct ext4_iloc *iloc)
5412 if (test_opt(inode->i_sb, I_VERSION))
5413 inode_inc_iversion(inode);
5415 /* the do_update_inode consumes one bh->b_count */
5418 /* ext4_do_update_inode() does jbd2_journal_dirty_metadata */
5419 err = ext4_do_update_inode(handle, inode, iloc);
5425 * On success, We end up with an outstanding reference count against
5426 * iloc->bh. This _must_ be cleaned up later.
5430 ext4_reserve_inode_write(handle_t *handle, struct inode *inode,
5431 struct ext4_iloc *iloc)
5435 err = ext4_get_inode_loc(inode, iloc);
5437 BUFFER_TRACE(iloc->bh, "get_write_access");
5438 err = ext4_journal_get_write_access(handle, iloc->bh);
5444 ext4_std_error(inode->i_sb, err);
5449 * Expand an inode by new_extra_isize bytes.
5450 * Returns 0 on success or negative error number on failure.
5452 static int ext4_expand_extra_isize(struct inode *inode,
5453 unsigned int new_extra_isize,
5454 struct ext4_iloc iloc,
5457 struct ext4_inode *raw_inode;
5458 struct ext4_xattr_ibody_header *header;
5459 struct ext4_xattr_entry *entry;
5461 if (EXT4_I(inode)->i_extra_isize >= new_extra_isize)
5464 raw_inode = ext4_raw_inode(&iloc);
5466 header = IHDR(inode, raw_inode);
5467 entry = IFIRST(header);
5469 /* No extended attributes present */
5470 if (!(EXT4_I(inode)->i_state & EXT4_STATE_XATTR) ||
5471 header->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC)) {
5472 memset((void *)raw_inode + EXT4_GOOD_OLD_INODE_SIZE, 0,
5474 EXT4_I(inode)->i_extra_isize = new_extra_isize;
5478 /* try to expand with EAs present */
5479 return ext4_expand_extra_isize_ea(inode, new_extra_isize,
5484 * What we do here is to mark the in-core inode as clean with respect to inode
5485 * dirtiness (it may still be data-dirty).
5486 * This means that the in-core inode may be reaped by prune_icache
5487 * without having to perform any I/O. This is a very good thing,
5488 * because *any* task may call prune_icache - even ones which
5489 * have a transaction open against a different journal.
5491 * Is this cheating? Not really. Sure, we haven't written the
5492 * inode out, but prune_icache isn't a user-visible syncing function.
5493 * Whenever the user wants stuff synced (sys_sync, sys_msync, sys_fsync)
5494 * we start and wait on commits.
5496 * Is this efficient/effective? Well, we're being nice to the system
5497 * by cleaning up our inodes proactively so they can be reaped
5498 * without I/O. But we are potentially leaving up to five seconds'
5499 * worth of inodes floating about which prune_icache wants us to
5500 * write out. One way to fix that would be to get prune_icache()
5501 * to do a write_super() to free up some memory. It has the desired
5504 int ext4_mark_inode_dirty(handle_t *handle, struct inode *inode)
5506 struct ext4_iloc iloc;
5507 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
5508 static unsigned int mnt_count;
5512 err = ext4_reserve_inode_write(handle, inode, &iloc);
5513 if (ext4_handle_valid(handle) &&
5514 EXT4_I(inode)->i_extra_isize < sbi->s_want_extra_isize &&
5515 !(EXT4_I(inode)->i_state & EXT4_STATE_NO_EXPAND)) {
5517 * We need extra buffer credits since we may write into EA block
5518 * with this same handle. If journal_extend fails, then it will
5519 * only result in a minor loss of functionality for that inode.
5520 * If this is felt to be critical, then e2fsck should be run to
5521 * force a large enough s_min_extra_isize.
5523 if ((jbd2_journal_extend(handle,
5524 EXT4_DATA_TRANS_BLOCKS(inode->i_sb))) == 0) {
5525 ret = ext4_expand_extra_isize(inode,
5526 sbi->s_want_extra_isize,
5529 EXT4_I(inode)->i_state |= EXT4_STATE_NO_EXPAND;
5531 le16_to_cpu(sbi->s_es->s_mnt_count)) {
5532 ext4_warning(inode->i_sb, __func__,
5533 "Unable to expand inode %lu. Delete"
5534 " some EAs or run e2fsck.",
5537 le16_to_cpu(sbi->s_es->s_mnt_count);
5543 err = ext4_mark_iloc_dirty(handle, inode, &iloc);
5548 * ext4_dirty_inode() is called from __mark_inode_dirty()
5550 * We're really interested in the case where a file is being extended.
5551 * i_size has been changed by generic_commit_write() and we thus need
5552 * to include the updated inode in the current transaction.
5554 * Also, vfs_dq_alloc_block() will always dirty the inode when blocks
5555 * are allocated to the file.
5557 * If the inode is marked synchronous, we don't honour that here - doing
5558 * so would cause a commit on atime updates, which we don't bother doing.
5559 * We handle synchronous inodes at the highest possible level.
5561 void ext4_dirty_inode(struct inode *inode)
5565 handle = ext4_journal_start(inode, 2);
5569 ext4_mark_inode_dirty(handle, inode);
5571 ext4_journal_stop(handle);
5578 * Bind an inode's backing buffer_head into this transaction, to prevent
5579 * it from being flushed to disk early. Unlike
5580 * ext4_reserve_inode_write, this leaves behind no bh reference and
5581 * returns no iloc structure, so the caller needs to repeat the iloc
5582 * lookup to mark the inode dirty later.
5584 static int ext4_pin_inode(handle_t *handle, struct inode *inode)
5586 struct ext4_iloc iloc;
5590 err = ext4_get_inode_loc(inode, &iloc);
5592 BUFFER_TRACE(iloc.bh, "get_write_access");
5593 err = jbd2_journal_get_write_access(handle, iloc.bh);
5595 err = ext4_handle_dirty_metadata(handle,
5601 ext4_std_error(inode->i_sb, err);
5606 int ext4_change_inode_journal_flag(struct inode *inode, int val)
5613 * We have to be very careful here: changing a data block's
5614 * journaling status dynamically is dangerous. If we write a
5615 * data block to the journal, change the status and then delete
5616 * that block, we risk forgetting to revoke the old log record
5617 * from the journal and so a subsequent replay can corrupt data.
5618 * So, first we make sure that the journal is empty and that
5619 * nobody is changing anything.
5622 journal = EXT4_JOURNAL(inode);
5625 if (is_journal_aborted(journal))
5628 jbd2_journal_lock_updates(journal);
5629 jbd2_journal_flush(journal);
5632 * OK, there are no updates running now, and all cached data is
5633 * synced to disk. We are now in a completely consistent state
5634 * which doesn't have anything in the journal, and we know that
5635 * no filesystem updates are running, so it is safe to modify
5636 * the inode's in-core data-journaling state flag now.
5640 EXT4_I(inode)->i_flags |= EXT4_JOURNAL_DATA_FL;
5642 EXT4_I(inode)->i_flags &= ~EXT4_JOURNAL_DATA_FL;
5643 ext4_set_aops(inode);
5645 jbd2_journal_unlock_updates(journal);
5647 /* Finally we can mark the inode as dirty. */
5649 handle = ext4_journal_start(inode, 1);
5651 return PTR_ERR(handle);
5653 err = ext4_mark_inode_dirty(handle, inode);
5654 ext4_handle_sync(handle);
5655 ext4_journal_stop(handle);
5656 ext4_std_error(inode->i_sb, err);
5661 static int ext4_bh_unmapped(handle_t *handle, struct buffer_head *bh)
5663 return !buffer_mapped(bh);
5666 int ext4_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
5668 struct page *page = vmf->page;
5673 struct file *file = vma->vm_file;
5674 struct inode *inode = file->f_path.dentry->d_inode;
5675 struct address_space *mapping = inode->i_mapping;
5678 * Get i_alloc_sem to stop truncates messing with the inode. We cannot
5679 * get i_mutex because we are already holding mmap_sem.
5681 down_read(&inode->i_alloc_sem);
5682 size = i_size_read(inode);
5683 if (page->mapping != mapping || size <= page_offset(page)
5684 || !PageUptodate(page)) {
5685 /* page got truncated from under us? */
5689 if (PageMappedToDisk(page))
5692 if (page->index == size >> PAGE_CACHE_SHIFT)
5693 len = size & ~PAGE_CACHE_MASK;
5695 len = PAGE_CACHE_SIZE;
5699 * return if we have all the buffers mapped. This avoid
5700 * the need to call write_begin/write_end which does a
5701 * journal_start/journal_stop which can block and take
5704 if (page_has_buffers(page)) {
5705 if (!walk_page_buffers(NULL, page_buffers(page), 0, len, NULL,
5706 ext4_bh_unmapped)) {
5713 * OK, we need to fill the hole... Do write_begin write_end
5714 * to do block allocation/reservation.We are not holding
5715 * inode.i__mutex here. That allow * parallel write_begin,
5716 * write_end call. lock_page prevent this from happening
5717 * on the same page though
5719 ret = mapping->a_ops->write_begin(file, mapping, page_offset(page),
5720 len, AOP_FLAG_UNINTERRUPTIBLE, &page, &fsdata);
5723 ret = mapping->a_ops->write_end(file, mapping, page_offset(page),
5724 len, len, page, fsdata);
5730 ret = VM_FAULT_SIGBUS;
5731 up_read(&inode->i_alloc_sem);