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>
41 #include <linux/kernel.h>
43 #include "ext4_jbd2.h"
46 #include "ext4_extents.h"
48 #include <trace/events/ext4.h>
50 #define MPAGE_DA_EXTENT_TAIL 0x01
52 static inline int ext4_begin_ordered_truncate(struct inode *inode,
55 return jbd2_journal_begin_ordered_truncate(
56 EXT4_SB(inode->i_sb)->s_journal,
57 &EXT4_I(inode)->jinode,
61 static void ext4_invalidatepage(struct page *page, unsigned long offset);
64 * Test whether an inode is a fast symlink.
66 static int ext4_inode_is_fast_symlink(struct inode *inode)
68 int ea_blocks = EXT4_I(inode)->i_file_acl ?
69 (inode->i_sb->s_blocksize >> 9) : 0;
71 return (S_ISLNK(inode->i_mode) && inode->i_blocks - ea_blocks == 0);
75 * Work out how many blocks we need to proceed with the next chunk of a
76 * truncate transaction.
78 static unsigned long blocks_for_truncate(struct inode *inode)
82 needed = inode->i_blocks >> (inode->i_sb->s_blocksize_bits - 9);
84 /* Give ourselves just enough room to cope with inodes in which
85 * i_blocks is corrupt: we've seen disk corruptions in the past
86 * which resulted in random data in an inode which looked enough
87 * like a regular file for ext4 to try to delete it. Things
88 * will go a bit crazy if that happens, but at least we should
89 * try not to panic the whole kernel. */
93 /* But we need to bound the transaction so we don't overflow the
95 if (needed > EXT4_MAX_TRANS_DATA)
96 needed = EXT4_MAX_TRANS_DATA;
98 return EXT4_DATA_TRANS_BLOCKS(inode->i_sb) + needed;
102 * Truncate transactions can be complex and absolutely huge. So we need to
103 * be able to restart the transaction at a conventient checkpoint to make
104 * sure we don't overflow the journal.
106 * start_transaction gets us a new handle for a truncate transaction,
107 * and extend_transaction tries to extend the existing one a bit. If
108 * extend fails, we need to propagate the failure up and restart the
109 * transaction in the top-level truncate loop. --sct
111 static handle_t *start_transaction(struct inode *inode)
115 result = ext4_journal_start(inode, blocks_for_truncate(inode));
119 ext4_std_error(inode->i_sb, PTR_ERR(result));
124 * Try to extend this transaction for the purposes of truncation.
126 * Returns 0 if we managed to create more room. If we can't create more
127 * room, and the transaction must be restarted we return 1.
129 static int try_to_extend_transaction(handle_t *handle, struct inode *inode)
131 if (!ext4_handle_valid(handle))
133 if (ext4_handle_has_enough_credits(handle, EXT4_RESERVE_TRANS_BLOCKS+1))
135 if (!ext4_journal_extend(handle, blocks_for_truncate(inode)))
141 * Restart the transaction associated with *handle. This does a commit,
142 * so before we call here everything must be consistently dirtied against
145 int ext4_truncate_restart_trans(handle_t *handle, struct inode *inode,
151 * Drop i_data_sem to avoid deadlock with ext4_get_blocks At this
152 * moment, get_block can be called only for blocks inside i_size since
153 * page cache has been already dropped and writes are blocked by
154 * i_mutex. So we can safely drop the i_data_sem here.
156 BUG_ON(EXT4_JOURNAL(inode) == NULL);
157 jbd_debug(2, "restarting handle %p\n", handle);
158 up_write(&EXT4_I(inode)->i_data_sem);
159 ret = ext4_journal_restart(handle, blocks_for_truncate(inode));
160 down_write(&EXT4_I(inode)->i_data_sem);
161 ext4_discard_preallocations(inode);
167 * Called at the last iput() if i_nlink is zero.
169 void ext4_delete_inode(struct inode *inode)
174 if (ext4_should_order_data(inode))
175 ext4_begin_ordered_truncate(inode, 0);
176 truncate_inode_pages(&inode->i_data, 0);
178 if (is_bad_inode(inode))
181 handle = ext4_journal_start(inode, blocks_for_truncate(inode)+3);
182 if (IS_ERR(handle)) {
183 ext4_std_error(inode->i_sb, PTR_ERR(handle));
185 * If we're going to skip the normal cleanup, we still need to
186 * make sure that the in-core orphan linked list is properly
189 ext4_orphan_del(NULL, inode);
194 ext4_handle_sync(handle);
196 err = ext4_mark_inode_dirty(handle, inode);
198 ext4_warning(inode->i_sb,
199 "couldn't mark inode dirty (err %d)", err);
203 ext4_truncate(inode);
206 * ext4_ext_truncate() doesn't reserve any slop when it
207 * restarts journal transactions; therefore there may not be
208 * enough credits left in the handle to remove the inode from
209 * the orphan list and set the dtime field.
211 if (!ext4_handle_has_enough_credits(handle, 3)) {
212 err = ext4_journal_extend(handle, 3);
214 err = ext4_journal_restart(handle, 3);
216 ext4_warning(inode->i_sb,
217 "couldn't extend journal (err %d)", err);
219 ext4_journal_stop(handle);
225 * Kill off the orphan record which ext4_truncate created.
226 * AKPM: I think this can be inside the above `if'.
227 * Note that ext4_orphan_del() has to be able to cope with the
228 * deletion of a non-existent orphan - this is because we don't
229 * know if ext4_truncate() actually created an orphan record.
230 * (Well, we could do this if we need to, but heck - it works)
232 ext4_orphan_del(handle, inode);
233 EXT4_I(inode)->i_dtime = get_seconds();
236 * One subtle ordering requirement: if anything has gone wrong
237 * (transaction abort, IO errors, whatever), then we can still
238 * do these next steps (the fs will already have been marked as
239 * having errors), but we can't free the inode if the mark_dirty
242 if (ext4_mark_inode_dirty(handle, inode))
243 /* If that failed, just do the required in-core inode clear. */
246 ext4_free_inode(handle, inode);
247 ext4_journal_stop(handle);
250 clear_inode(inode); /* We must guarantee clearing of inode... */
256 struct buffer_head *bh;
259 static inline void add_chain(Indirect *p, struct buffer_head *bh, __le32 *v)
261 p->key = *(p->p = v);
266 * ext4_block_to_path - parse the block number into array of offsets
267 * @inode: inode in question (we are only interested in its superblock)
268 * @i_block: block number to be parsed
269 * @offsets: array to store the offsets in
270 * @boundary: set this non-zero if the referred-to block is likely to be
271 * followed (on disk) by an indirect block.
273 * To store the locations of file's data ext4 uses a data structure common
274 * for UNIX filesystems - tree of pointers anchored in the inode, with
275 * data blocks at leaves and indirect blocks in intermediate nodes.
276 * This function translates the block number into path in that tree -
277 * return value is the path length and @offsets[n] is the offset of
278 * pointer to (n+1)th node in the nth one. If @block is out of range
279 * (negative or too large) warning is printed and zero returned.
281 * Note: function doesn't find node addresses, so no IO is needed. All
282 * we need to know is the capacity of indirect blocks (taken from the
287 * Portability note: the last comparison (check that we fit into triple
288 * indirect block) is spelled differently, because otherwise on an
289 * architecture with 32-bit longs and 8Kb pages we might get into trouble
290 * if our filesystem had 8Kb blocks. We might use long long, but that would
291 * kill us on x86. Oh, well, at least the sign propagation does not matter -
292 * i_block would have to be negative in the very beginning, so we would not
296 static int ext4_block_to_path(struct inode *inode,
298 ext4_lblk_t offsets[4], int *boundary)
300 int ptrs = EXT4_ADDR_PER_BLOCK(inode->i_sb);
301 int ptrs_bits = EXT4_ADDR_PER_BLOCK_BITS(inode->i_sb);
302 const long direct_blocks = EXT4_NDIR_BLOCKS,
303 indirect_blocks = ptrs,
304 double_blocks = (1 << (ptrs_bits * 2));
308 if (i_block < direct_blocks) {
309 offsets[n++] = i_block;
310 final = direct_blocks;
311 } else if ((i_block -= direct_blocks) < indirect_blocks) {
312 offsets[n++] = EXT4_IND_BLOCK;
313 offsets[n++] = i_block;
315 } else if ((i_block -= indirect_blocks) < double_blocks) {
316 offsets[n++] = EXT4_DIND_BLOCK;
317 offsets[n++] = i_block >> ptrs_bits;
318 offsets[n++] = i_block & (ptrs - 1);
320 } else if (((i_block -= double_blocks) >> (ptrs_bits * 2)) < ptrs) {
321 offsets[n++] = EXT4_TIND_BLOCK;
322 offsets[n++] = i_block >> (ptrs_bits * 2);
323 offsets[n++] = (i_block >> ptrs_bits) & (ptrs - 1);
324 offsets[n++] = i_block & (ptrs - 1);
327 ext4_warning(inode->i_sb, "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 ext4_update_inode_fsync_trans(handle, inode, 1);
989 map_bh(bh_result, inode->i_sb, le32_to_cpu(chain[depth-1].key));
990 if (count > blocks_to_boundary)
991 set_buffer_boundary(bh_result);
993 /* Clean up and exit */
994 partial = chain + depth - 1; /* the whole chain */
996 while (partial > chain) {
997 BUFFER_TRACE(partial->bh, "call brelse");
1001 BUFFER_TRACE(bh_result, "returned");
1007 qsize_t *ext4_get_reserved_space(struct inode *inode)
1009 return &EXT4_I(inode)->i_reserved_quota;
1014 * Calculate the number of metadata blocks need to reserve
1015 * to allocate a new block at @lblocks for non extent file based file
1017 static int ext4_indirect_calc_metadata_amount(struct inode *inode,
1020 struct ext4_inode_info *ei = EXT4_I(inode);
1021 int dind_mask = EXT4_ADDR_PER_BLOCK(inode->i_sb) - 1;
1024 if (lblock < EXT4_NDIR_BLOCKS)
1027 lblock -= EXT4_NDIR_BLOCKS;
1029 if (ei->i_da_metadata_calc_len &&
1030 (lblock & dind_mask) == ei->i_da_metadata_calc_last_lblock) {
1031 ei->i_da_metadata_calc_len++;
1034 ei->i_da_metadata_calc_last_lblock = lblock & dind_mask;
1035 ei->i_da_metadata_calc_len = 1;
1036 blk_bits = roundup_pow_of_two(lblock + 1);
1037 return (blk_bits / EXT4_ADDR_PER_BLOCK_BITS(inode->i_sb)) + 1;
1041 * Calculate the number of metadata blocks need to reserve
1042 * to allocate a block located at @lblock
1044 static int ext4_calc_metadata_amount(struct inode *inode, sector_t lblock)
1046 if (EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL)
1047 return ext4_ext_calc_metadata_amount(inode, lblock);
1049 return ext4_indirect_calc_metadata_amount(inode, lblock);
1053 * Called with i_data_sem down, which is important since we can call
1054 * ext4_discard_preallocations() from here.
1056 void ext4_da_update_reserve_space(struct inode *inode,
1057 int used, int quota_claim)
1059 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
1060 struct ext4_inode_info *ei = EXT4_I(inode);
1061 int mdb_free = 0, allocated_meta_blocks = 0;
1063 spin_lock(&ei->i_block_reservation_lock);
1064 trace_ext4_da_update_reserve_space(inode, used);
1065 if (unlikely(used > ei->i_reserved_data_blocks)) {
1066 ext4_msg(inode->i_sb, KERN_NOTICE, "%s: ino %lu, used %d "
1067 "with only %d reserved data blocks\n",
1068 __func__, inode->i_ino, used,
1069 ei->i_reserved_data_blocks);
1071 used = ei->i_reserved_data_blocks;
1074 /* Update per-inode reservations */
1075 ei->i_reserved_data_blocks -= used;
1076 used += ei->i_allocated_meta_blocks;
1077 ei->i_reserved_meta_blocks -= ei->i_allocated_meta_blocks;
1078 allocated_meta_blocks = ei->i_allocated_meta_blocks;
1079 ei->i_allocated_meta_blocks = 0;
1080 percpu_counter_sub(&sbi->s_dirtyblocks_counter, used);
1082 if (ei->i_reserved_data_blocks == 0) {
1084 * We can release all of the reserved metadata blocks
1085 * only when we have written all of the delayed
1086 * allocation blocks.
1088 mdb_free = ei->i_reserved_meta_blocks;
1089 ei->i_reserved_meta_blocks = 0;
1090 ei->i_da_metadata_calc_len = 0;
1091 percpu_counter_sub(&sbi->s_dirtyblocks_counter, mdb_free);
1093 spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
1095 /* Update quota subsystem */
1097 vfs_dq_claim_block(inode, used);
1099 vfs_dq_release_reservation_block(inode, mdb_free);
1102 * We did fallocate with an offset that is already delayed
1103 * allocated. So on delayed allocated writeback we should
1104 * not update the quota for allocated blocks. But then
1105 * converting an fallocate region to initialized region would
1106 * have caused a metadata allocation. So claim quota for
1109 if (allocated_meta_blocks)
1110 vfs_dq_claim_block(inode, allocated_meta_blocks);
1111 vfs_dq_release_reservation_block(inode, mdb_free + used);
1115 * If we have done all the pending block allocations and if
1116 * there aren't any writers on the inode, we can discard the
1117 * inode's preallocations.
1119 if ((ei->i_reserved_data_blocks == 0) &&
1120 (atomic_read(&inode->i_writecount) == 0))
1121 ext4_discard_preallocations(inode);
1124 static int check_block_validity(struct inode *inode, const char *msg,
1125 sector_t logical, sector_t phys, int len)
1127 if (!ext4_data_block_valid(EXT4_SB(inode->i_sb), phys, len)) {
1128 __ext4_error(inode->i_sb, msg,
1129 "inode #%lu logical block %llu mapped to %llu "
1130 "(size %d)", inode->i_ino,
1131 (unsigned long long) logical,
1132 (unsigned long long) phys, len);
1139 * Return the number of contiguous dirty pages in a given inode
1140 * starting at page frame idx.
1142 static pgoff_t ext4_num_dirty_pages(struct inode *inode, pgoff_t idx,
1143 unsigned int max_pages)
1145 struct address_space *mapping = inode->i_mapping;
1147 struct pagevec pvec;
1149 int i, nr_pages, done = 0;
1153 pagevec_init(&pvec, 0);
1156 nr_pages = pagevec_lookup_tag(&pvec, mapping, &index,
1157 PAGECACHE_TAG_DIRTY,
1158 (pgoff_t)PAGEVEC_SIZE);
1161 for (i = 0; i < nr_pages; i++) {
1162 struct page *page = pvec.pages[i];
1163 struct buffer_head *bh, *head;
1166 if (unlikely(page->mapping != mapping) ||
1168 PageWriteback(page) ||
1169 page->index != idx) {
1174 if (page_has_buffers(page)) {
1175 bh = head = page_buffers(page);
1177 if (!buffer_delay(bh) &&
1178 !buffer_unwritten(bh))
1180 bh = bh->b_this_page;
1181 } while (!done && (bh != head));
1188 if (num >= max_pages)
1191 pagevec_release(&pvec);
1197 * The ext4_get_blocks() function tries to look up the requested blocks,
1198 * and returns if the blocks are already mapped.
1200 * Otherwise it takes the write lock of the i_data_sem and allocate blocks
1201 * and store the allocated blocks in the result buffer head and mark it
1204 * If file type is extents based, it will call ext4_ext_get_blocks(),
1205 * Otherwise, call with ext4_ind_get_blocks() to handle indirect mapping
1208 * On success, it returns the number of blocks being mapped or allocate.
1209 * if create==0 and the blocks are pre-allocated and uninitialized block,
1210 * the result buffer head is unmapped. If the create ==1, it will make sure
1211 * the buffer head is mapped.
1213 * It returns 0 if plain look up failed (blocks have not been allocated), in
1214 * that casem, buffer head is unmapped
1216 * It returns the error in case of allocation failure.
1218 int ext4_get_blocks(handle_t *handle, struct inode *inode, sector_t block,
1219 unsigned int max_blocks, struct buffer_head *bh,
1224 clear_buffer_mapped(bh);
1225 clear_buffer_unwritten(bh);
1227 ext_debug("ext4_get_blocks(): inode %lu, flag %d, max_blocks %u,"
1228 "logical block %lu\n", inode->i_ino, flags, max_blocks,
1229 (unsigned long)block);
1231 * Try to see if we can get the block without requesting a new
1232 * file system block.
1234 down_read((&EXT4_I(inode)->i_data_sem));
1235 if (EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL) {
1236 retval = ext4_ext_get_blocks(handle, inode, block, max_blocks,
1239 retval = ext4_ind_get_blocks(handle, inode, block, max_blocks,
1242 up_read((&EXT4_I(inode)->i_data_sem));
1244 if (retval > 0 && buffer_mapped(bh)) {
1245 int ret = check_block_validity(inode, "file system corruption",
1246 block, bh->b_blocknr, retval);
1251 /* If it is only a block(s) look up */
1252 if ((flags & EXT4_GET_BLOCKS_CREATE) == 0)
1256 * Returns if the blocks have already allocated
1258 * Note that if blocks have been preallocated
1259 * ext4_ext_get_block() returns th create = 0
1260 * with buffer head unmapped.
1262 if (retval > 0 && buffer_mapped(bh))
1266 * When we call get_blocks without the create flag, the
1267 * BH_Unwritten flag could have gotten set if the blocks
1268 * requested were part of a uninitialized extent. We need to
1269 * clear this flag now that we are committed to convert all or
1270 * part of the uninitialized extent to be an initialized
1271 * extent. This is because we need to avoid the combination
1272 * of BH_Unwritten and BH_Mapped flags being simultaneously
1273 * set on the buffer_head.
1275 clear_buffer_unwritten(bh);
1278 * New blocks allocate and/or writing to uninitialized extent
1279 * will possibly result in updating i_data, so we take
1280 * the write lock of i_data_sem, and call get_blocks()
1281 * with create == 1 flag.
1283 down_write((&EXT4_I(inode)->i_data_sem));
1286 * if the caller is from delayed allocation writeout path
1287 * we have already reserved fs blocks for allocation
1288 * let the underlying get_block() function know to
1289 * avoid double accounting
1291 if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE)
1292 EXT4_I(inode)->i_delalloc_reserved_flag = 1;
1294 * We need to check for EXT4 here because migrate
1295 * could have changed the inode type in between
1297 if (EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL) {
1298 retval = ext4_ext_get_blocks(handle, inode, block, max_blocks,
1301 retval = ext4_ind_get_blocks(handle, inode, block,
1302 max_blocks, bh, flags);
1304 if (retval > 0 && buffer_new(bh)) {
1306 * We allocated new blocks which will result in
1307 * i_data's format changing. Force the migrate
1308 * to fail by clearing migrate flags
1310 ext4_clear_inode_state(inode, EXT4_STATE_EXT_MIGRATE);
1314 * Update reserved blocks/metadata blocks after successful
1315 * block allocation which had been deferred till now. We don't
1316 * support fallocate for non extent files. So we can update
1317 * reserve space here.
1320 (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE))
1321 ext4_da_update_reserve_space(inode, retval, 1);
1323 if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE)
1324 EXT4_I(inode)->i_delalloc_reserved_flag = 0;
1326 up_write((&EXT4_I(inode)->i_data_sem));
1327 if (retval > 0 && buffer_mapped(bh)) {
1328 int ret = check_block_validity(inode, "file system "
1329 "corruption after allocation",
1330 block, bh->b_blocknr, retval);
1337 /* Maximum number of blocks we map for direct IO at once. */
1338 #define DIO_MAX_BLOCKS 4096
1340 int ext4_get_block(struct inode *inode, sector_t iblock,
1341 struct buffer_head *bh_result, int create)
1343 handle_t *handle = ext4_journal_current_handle();
1344 int ret = 0, started = 0;
1345 unsigned max_blocks = bh_result->b_size >> inode->i_blkbits;
1348 if (create && !handle) {
1349 /* Direct IO write... */
1350 if (max_blocks > DIO_MAX_BLOCKS)
1351 max_blocks = DIO_MAX_BLOCKS;
1352 dio_credits = ext4_chunk_trans_blocks(inode, max_blocks);
1353 handle = ext4_journal_start(inode, dio_credits);
1354 if (IS_ERR(handle)) {
1355 ret = PTR_ERR(handle);
1361 ret = ext4_get_blocks(handle, inode, iblock, max_blocks, bh_result,
1362 create ? EXT4_GET_BLOCKS_CREATE : 0);
1364 bh_result->b_size = (ret << inode->i_blkbits);
1368 ext4_journal_stop(handle);
1374 * `handle' can be NULL if create is zero
1376 struct buffer_head *ext4_getblk(handle_t *handle, struct inode *inode,
1377 ext4_lblk_t block, int create, int *errp)
1379 struct buffer_head dummy;
1383 J_ASSERT(handle != NULL || create == 0);
1386 dummy.b_blocknr = -1000;
1387 buffer_trace_init(&dummy.b_history);
1389 flags |= EXT4_GET_BLOCKS_CREATE;
1390 err = ext4_get_blocks(handle, inode, block, 1, &dummy, flags);
1392 * ext4_get_blocks() returns number of blocks mapped. 0 in
1401 if (!err && buffer_mapped(&dummy)) {
1402 struct buffer_head *bh;
1403 bh = sb_getblk(inode->i_sb, dummy.b_blocknr);
1408 if (buffer_new(&dummy)) {
1409 J_ASSERT(create != 0);
1410 J_ASSERT(handle != NULL);
1413 * Now that we do not always journal data, we should
1414 * keep in mind whether this should always journal the
1415 * new buffer as metadata. For now, regular file
1416 * writes use ext4_get_block instead, so it's not a
1420 BUFFER_TRACE(bh, "call get_create_access");
1421 fatal = ext4_journal_get_create_access(handle, bh);
1422 if (!fatal && !buffer_uptodate(bh)) {
1423 memset(bh->b_data, 0, inode->i_sb->s_blocksize);
1424 set_buffer_uptodate(bh);
1427 BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
1428 err = ext4_handle_dirty_metadata(handle, inode, bh);
1432 BUFFER_TRACE(bh, "not a new buffer");
1445 struct buffer_head *ext4_bread(handle_t *handle, struct inode *inode,
1446 ext4_lblk_t block, int create, int *err)
1448 struct buffer_head *bh;
1450 bh = ext4_getblk(handle, inode, block, create, err);
1453 if (buffer_uptodate(bh))
1455 ll_rw_block(READ_META, 1, &bh);
1457 if (buffer_uptodate(bh))
1464 static int walk_page_buffers(handle_t *handle,
1465 struct buffer_head *head,
1469 int (*fn)(handle_t *handle,
1470 struct buffer_head *bh))
1472 struct buffer_head *bh;
1473 unsigned block_start, block_end;
1474 unsigned blocksize = head->b_size;
1476 struct buffer_head *next;
1478 for (bh = head, block_start = 0;
1479 ret == 0 && (bh != head || !block_start);
1480 block_start = block_end, bh = next) {
1481 next = bh->b_this_page;
1482 block_end = block_start + blocksize;
1483 if (block_end <= from || block_start >= to) {
1484 if (partial && !buffer_uptodate(bh))
1488 err = (*fn)(handle, bh);
1496 * To preserve ordering, it is essential that the hole instantiation and
1497 * the data write be encapsulated in a single transaction. We cannot
1498 * close off a transaction and start a new one between the ext4_get_block()
1499 * and the commit_write(). So doing the jbd2_journal_start at the start of
1500 * prepare_write() is the right place.
1502 * Also, this function can nest inside ext4_writepage() ->
1503 * block_write_full_page(). In that case, we *know* that ext4_writepage()
1504 * has generated enough buffer credits to do the whole page. So we won't
1505 * block on the journal in that case, which is good, because the caller may
1508 * By accident, ext4 can be reentered when a transaction is open via
1509 * quota file writes. If we were to commit the transaction while thus
1510 * reentered, there can be a deadlock - we would be holding a quota
1511 * lock, and the commit would never complete if another thread had a
1512 * transaction open and was blocking on the quota lock - a ranking
1515 * So what we do is to rely on the fact that jbd2_journal_stop/journal_start
1516 * will _not_ run commit under these circumstances because handle->h_ref
1517 * is elevated. We'll still have enough credits for the tiny quotafile
1520 static int do_journal_get_write_access(handle_t *handle,
1521 struct buffer_head *bh)
1523 if (!buffer_mapped(bh) || buffer_freed(bh))
1525 return ext4_journal_get_write_access(handle, bh);
1529 * Truncate blocks that were not used by write. We have to truncate the
1530 * pagecache as well so that corresponding buffers get properly unmapped.
1532 static void ext4_truncate_failed_write(struct inode *inode)
1534 truncate_inode_pages(inode->i_mapping, inode->i_size);
1535 ext4_truncate(inode);
1538 static int ext4_get_block_write(struct inode *inode, sector_t iblock,
1539 struct buffer_head *bh_result, int create);
1540 static int ext4_write_begin(struct file *file, struct address_space *mapping,
1541 loff_t pos, unsigned len, unsigned flags,
1542 struct page **pagep, void **fsdata)
1544 struct inode *inode = mapping->host;
1545 int ret, needed_blocks;
1552 trace_ext4_write_begin(inode, pos, len, flags);
1554 * Reserve one block more for addition to orphan list in case
1555 * we allocate blocks but write fails for some reason
1557 needed_blocks = ext4_writepage_trans_blocks(inode) + 1;
1558 index = pos >> PAGE_CACHE_SHIFT;
1559 from = pos & (PAGE_CACHE_SIZE - 1);
1563 handle = ext4_journal_start(inode, needed_blocks);
1564 if (IS_ERR(handle)) {
1565 ret = PTR_ERR(handle);
1569 /* We cannot recurse into the filesystem as the transaction is already
1571 flags |= AOP_FLAG_NOFS;
1573 page = grab_cache_page_write_begin(mapping, index, flags);
1575 ext4_journal_stop(handle);
1581 if (ext4_should_dioread_nolock(inode))
1582 ret = block_write_begin(file, mapping, pos, len, flags, pagep,
1583 fsdata, ext4_get_block_write);
1585 ret = block_write_begin(file, mapping, pos, len, flags, pagep,
1586 fsdata, ext4_get_block);
1588 if (!ret && ext4_should_journal_data(inode)) {
1589 ret = walk_page_buffers(handle, page_buffers(page),
1590 from, to, NULL, do_journal_get_write_access);
1595 page_cache_release(page);
1597 * block_write_begin may have instantiated a few blocks
1598 * outside i_size. Trim these off again. Don't need
1599 * i_size_read because we hold i_mutex.
1601 * Add inode to orphan list in case we crash before
1604 if (pos + len > inode->i_size && ext4_can_truncate(inode))
1605 ext4_orphan_add(handle, inode);
1607 ext4_journal_stop(handle);
1608 if (pos + len > inode->i_size) {
1609 ext4_truncate_failed_write(inode);
1611 * If truncate failed early the inode might
1612 * still be on the orphan list; we need to
1613 * make sure the inode is removed from the
1614 * orphan list in that case.
1617 ext4_orphan_del(NULL, inode);
1621 if (ret == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
1627 /* For write_end() in data=journal mode */
1628 static int write_end_fn(handle_t *handle, struct buffer_head *bh)
1630 if (!buffer_mapped(bh) || buffer_freed(bh))
1632 set_buffer_uptodate(bh);
1633 return ext4_handle_dirty_metadata(handle, NULL, bh);
1636 static int ext4_generic_write_end(struct file *file,
1637 struct address_space *mapping,
1638 loff_t pos, unsigned len, unsigned copied,
1639 struct page *page, void *fsdata)
1641 int i_size_changed = 0;
1642 struct inode *inode = mapping->host;
1643 handle_t *handle = ext4_journal_current_handle();
1645 copied = block_write_end(file, mapping, pos, len, copied, page, fsdata);
1648 * No need to use i_size_read() here, the i_size
1649 * cannot change under us because we hold i_mutex.
1651 * But it's important to update i_size while still holding page lock:
1652 * page writeout could otherwise come in and zero beyond i_size.
1654 if (pos + copied > inode->i_size) {
1655 i_size_write(inode, pos + copied);
1659 if (pos + copied > EXT4_I(inode)->i_disksize) {
1660 /* We need to mark inode dirty even if
1661 * new_i_size is less that inode->i_size
1662 * bu greater than i_disksize.(hint delalloc)
1664 ext4_update_i_disksize(inode, (pos + copied));
1668 page_cache_release(page);
1671 * Don't mark the inode dirty under page lock. First, it unnecessarily
1672 * makes the holding time of page lock longer. Second, it forces lock
1673 * ordering of page lock and transaction start for journaling
1677 ext4_mark_inode_dirty(handle, inode);
1683 * We need to pick up the new inode size which generic_commit_write gave us
1684 * `file' can be NULL - eg, when called from page_symlink().
1686 * ext4 never places buffers on inode->i_mapping->private_list. metadata
1687 * buffers are managed internally.
1689 static int ext4_ordered_write_end(struct file *file,
1690 struct address_space *mapping,
1691 loff_t pos, unsigned len, unsigned copied,
1692 struct page *page, void *fsdata)
1694 handle_t *handle = ext4_journal_current_handle();
1695 struct inode *inode = mapping->host;
1698 trace_ext4_ordered_write_end(inode, pos, len, copied);
1699 ret = ext4_jbd2_file_inode(handle, inode);
1702 ret2 = ext4_generic_write_end(file, mapping, pos, len, copied,
1705 if (pos + len > inode->i_size && ext4_can_truncate(inode))
1706 /* if we have allocated more blocks and copied
1707 * less. We will have blocks allocated outside
1708 * inode->i_size. So truncate them
1710 ext4_orphan_add(handle, inode);
1714 ret2 = ext4_journal_stop(handle);
1718 if (pos + len > inode->i_size) {
1719 ext4_truncate_failed_write(inode);
1721 * If truncate failed early the inode might still be
1722 * on the orphan list; we need to make sure the inode
1723 * is removed from the orphan list in that case.
1726 ext4_orphan_del(NULL, inode);
1730 return ret ? ret : copied;
1733 static int ext4_writeback_write_end(struct file *file,
1734 struct address_space *mapping,
1735 loff_t pos, unsigned len, unsigned copied,
1736 struct page *page, void *fsdata)
1738 handle_t *handle = ext4_journal_current_handle();
1739 struct inode *inode = mapping->host;
1742 trace_ext4_writeback_write_end(inode, pos, len, copied);
1743 ret2 = ext4_generic_write_end(file, mapping, pos, len, copied,
1746 if (pos + len > inode->i_size && ext4_can_truncate(inode))
1747 /* if we have allocated more blocks and copied
1748 * less. We will have blocks allocated outside
1749 * inode->i_size. So truncate them
1751 ext4_orphan_add(handle, inode);
1756 ret2 = ext4_journal_stop(handle);
1760 if (pos + len > inode->i_size) {
1761 ext4_truncate_failed_write(inode);
1763 * If truncate failed early the inode might still be
1764 * on the orphan list; we need to make sure the inode
1765 * is removed from the orphan list in that case.
1768 ext4_orphan_del(NULL, inode);
1771 return ret ? ret : copied;
1774 static int ext4_journalled_write_end(struct file *file,
1775 struct address_space *mapping,
1776 loff_t pos, unsigned len, unsigned copied,
1777 struct page *page, void *fsdata)
1779 handle_t *handle = ext4_journal_current_handle();
1780 struct inode *inode = mapping->host;
1786 trace_ext4_journalled_write_end(inode, pos, len, copied);
1787 from = pos & (PAGE_CACHE_SIZE - 1);
1791 if (!PageUptodate(page))
1793 page_zero_new_buffers(page, from+copied, to);
1796 ret = walk_page_buffers(handle, page_buffers(page), from,
1797 to, &partial, write_end_fn);
1799 SetPageUptodate(page);
1800 new_i_size = pos + copied;
1801 if (new_i_size > inode->i_size)
1802 i_size_write(inode, pos+copied);
1803 ext4_set_inode_state(inode, EXT4_STATE_JDATA);
1804 if (new_i_size > EXT4_I(inode)->i_disksize) {
1805 ext4_update_i_disksize(inode, new_i_size);
1806 ret2 = ext4_mark_inode_dirty(handle, inode);
1812 page_cache_release(page);
1813 if (pos + len > inode->i_size && ext4_can_truncate(inode))
1814 /* if we have allocated more blocks and copied
1815 * less. We will have blocks allocated outside
1816 * inode->i_size. So truncate them
1818 ext4_orphan_add(handle, inode);
1820 ret2 = ext4_journal_stop(handle);
1823 if (pos + len > inode->i_size) {
1824 ext4_truncate_failed_write(inode);
1826 * If truncate failed early the inode might still be
1827 * on the orphan list; we need to make sure the inode
1828 * is removed from the orphan list in that case.
1831 ext4_orphan_del(NULL, inode);
1834 return ret ? ret : copied;
1838 * Reserve a single block located at lblock
1840 static int ext4_da_reserve_space(struct inode *inode, sector_t lblock)
1843 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
1844 struct ext4_inode_info *ei = EXT4_I(inode);
1845 unsigned long md_needed, md_reserved;
1848 * recalculate the amount of metadata blocks to reserve
1849 * in order to allocate nrblocks
1850 * worse case is one extent per block
1853 spin_lock(&ei->i_block_reservation_lock);
1854 md_reserved = ei->i_reserved_meta_blocks;
1855 md_needed = ext4_calc_metadata_amount(inode, lblock);
1856 trace_ext4_da_reserve_space(inode, md_needed);
1857 spin_unlock(&ei->i_block_reservation_lock);
1860 * Make quota reservation here to prevent quota overflow
1861 * later. Real quota accounting is done at pages writeout
1864 if (vfs_dq_reserve_block(inode, md_needed + 1))
1867 if (ext4_claim_free_blocks(sbi, md_needed + 1)) {
1868 vfs_dq_release_reservation_block(inode, md_needed + 1);
1869 if (ext4_should_retry_alloc(inode->i_sb, &retries)) {
1875 spin_lock(&ei->i_block_reservation_lock);
1876 ei->i_reserved_data_blocks++;
1877 ei->i_reserved_meta_blocks += md_needed;
1878 spin_unlock(&ei->i_block_reservation_lock);
1880 return 0; /* success */
1883 static void ext4_da_release_space(struct inode *inode, int to_free)
1885 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
1886 struct ext4_inode_info *ei = EXT4_I(inode);
1889 return; /* Nothing to release, exit */
1891 spin_lock(&EXT4_I(inode)->i_block_reservation_lock);
1893 if (unlikely(to_free > ei->i_reserved_data_blocks)) {
1895 * if there aren't enough reserved blocks, then the
1896 * counter is messed up somewhere. Since this
1897 * function is called from invalidate page, it's
1898 * harmless to return without any action.
1900 ext4_msg(inode->i_sb, KERN_NOTICE, "ext4_da_release_space: "
1901 "ino %lu, to_free %d with only %d reserved "
1902 "data blocks\n", inode->i_ino, to_free,
1903 ei->i_reserved_data_blocks);
1905 to_free = ei->i_reserved_data_blocks;
1907 ei->i_reserved_data_blocks -= to_free;
1909 if (ei->i_reserved_data_blocks == 0) {
1911 * We can release all of the reserved metadata blocks
1912 * only when we have written all of the delayed
1913 * allocation blocks.
1915 to_free += ei->i_reserved_meta_blocks;
1916 ei->i_reserved_meta_blocks = 0;
1917 ei->i_da_metadata_calc_len = 0;
1920 /* update fs dirty blocks counter */
1921 percpu_counter_sub(&sbi->s_dirtyblocks_counter, to_free);
1923 spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
1925 vfs_dq_release_reservation_block(inode, to_free);
1928 static void ext4_da_page_release_reservation(struct page *page,
1929 unsigned long offset)
1932 struct buffer_head *head, *bh;
1933 unsigned int curr_off = 0;
1935 head = page_buffers(page);
1938 unsigned int next_off = curr_off + bh->b_size;
1940 if ((offset <= curr_off) && (buffer_delay(bh))) {
1942 clear_buffer_delay(bh);
1944 curr_off = next_off;
1945 } while ((bh = bh->b_this_page) != head);
1946 ext4_da_release_space(page->mapping->host, to_release);
1950 * Delayed allocation stuff
1954 * mpage_da_submit_io - walks through extent of pages and try to write
1955 * them with writepage() call back
1957 * @mpd->inode: inode
1958 * @mpd->first_page: first page of the extent
1959 * @mpd->next_page: page after the last page of the extent
1961 * By the time mpage_da_submit_io() is called we expect all blocks
1962 * to be allocated. this may be wrong if allocation failed.
1964 * As pages are already locked by write_cache_pages(), we can't use it
1966 static int mpage_da_submit_io(struct mpage_da_data *mpd)
1969 struct pagevec pvec;
1970 unsigned long index, end;
1971 int ret = 0, err, nr_pages, i;
1972 struct inode *inode = mpd->inode;
1973 struct address_space *mapping = inode->i_mapping;
1975 BUG_ON(mpd->next_page <= mpd->first_page);
1977 * We need to start from the first_page to the next_page - 1
1978 * to make sure we also write the mapped dirty buffer_heads.
1979 * If we look at mpd->b_blocknr we would only be looking
1980 * at the currently mapped buffer_heads.
1982 index = mpd->first_page;
1983 end = mpd->next_page - 1;
1985 pagevec_init(&pvec, 0);
1986 while (index <= end) {
1987 nr_pages = pagevec_lookup(&pvec, mapping, index, PAGEVEC_SIZE);
1990 for (i = 0; i < nr_pages; i++) {
1991 struct page *page = pvec.pages[i];
1993 index = page->index;
1998 BUG_ON(!PageLocked(page));
1999 BUG_ON(PageWriteback(page));
2001 pages_skipped = mpd->wbc->pages_skipped;
2002 err = mapping->a_ops->writepage(page, mpd->wbc);
2003 if (!err && (pages_skipped == mpd->wbc->pages_skipped))
2005 * have successfully written the page
2006 * without skipping the same
2008 mpd->pages_written++;
2010 * In error case, we have to continue because
2011 * remaining pages are still locked
2012 * XXX: unlock and re-dirty them?
2017 pagevec_release(&pvec);
2023 * mpage_put_bnr_to_bhs - walk blocks and assign them actual numbers
2025 * @mpd->inode - inode to walk through
2026 * @exbh->b_blocknr - first block on a disk
2027 * @exbh->b_size - amount of space in bytes
2028 * @logical - first logical block to start assignment with
2030 * the function goes through all passed space and put actual disk
2031 * block numbers into buffer heads, dropping BH_Delay and BH_Unwritten
2033 static void mpage_put_bnr_to_bhs(struct mpage_da_data *mpd, sector_t logical,
2034 struct buffer_head *exbh)
2036 struct inode *inode = mpd->inode;
2037 struct address_space *mapping = inode->i_mapping;
2038 int blocks = exbh->b_size >> inode->i_blkbits;
2039 sector_t pblock = exbh->b_blocknr, cur_logical;
2040 struct buffer_head *head, *bh;
2042 struct pagevec pvec;
2045 index = logical >> (PAGE_CACHE_SHIFT - inode->i_blkbits);
2046 end = (logical + blocks - 1) >> (PAGE_CACHE_SHIFT - inode->i_blkbits);
2047 cur_logical = index << (PAGE_CACHE_SHIFT - inode->i_blkbits);
2049 pagevec_init(&pvec, 0);
2051 while (index <= end) {
2052 /* XXX: optimize tail */
2053 nr_pages = pagevec_lookup(&pvec, mapping, index, PAGEVEC_SIZE);
2056 for (i = 0; i < nr_pages; i++) {
2057 struct page *page = pvec.pages[i];
2059 index = page->index;
2064 BUG_ON(!PageLocked(page));
2065 BUG_ON(PageWriteback(page));
2066 BUG_ON(!page_has_buffers(page));
2068 bh = page_buffers(page);
2071 /* skip blocks out of the range */
2073 if (cur_logical >= logical)
2076 } while ((bh = bh->b_this_page) != head);
2079 if (cur_logical >= logical + blocks)
2082 if (buffer_delay(bh) ||
2083 buffer_unwritten(bh)) {
2085 BUG_ON(bh->b_bdev != inode->i_sb->s_bdev);
2087 if (buffer_delay(bh)) {
2088 clear_buffer_delay(bh);
2089 bh->b_blocknr = pblock;
2092 * unwritten already should have
2093 * blocknr assigned. Verify that
2095 clear_buffer_unwritten(bh);
2096 BUG_ON(bh->b_blocknr != pblock);
2099 } else if (buffer_mapped(bh))
2100 BUG_ON(bh->b_blocknr != pblock);
2102 if (buffer_uninit(exbh))
2103 set_buffer_uninit(bh);
2106 } while ((bh = bh->b_this_page) != head);
2108 pagevec_release(&pvec);
2114 * __unmap_underlying_blocks - just a helper function to unmap
2115 * set of blocks described by @bh
2117 static inline void __unmap_underlying_blocks(struct inode *inode,
2118 struct buffer_head *bh)
2120 struct block_device *bdev = inode->i_sb->s_bdev;
2123 blocks = bh->b_size >> inode->i_blkbits;
2124 for (i = 0; i < blocks; i++)
2125 unmap_underlying_metadata(bdev, bh->b_blocknr + i);
2128 static void ext4_da_block_invalidatepages(struct mpage_da_data *mpd,
2129 sector_t logical, long blk_cnt)
2133 struct pagevec pvec;
2134 struct inode *inode = mpd->inode;
2135 struct address_space *mapping = inode->i_mapping;
2137 index = logical >> (PAGE_CACHE_SHIFT - inode->i_blkbits);
2138 end = (logical + blk_cnt - 1) >>
2139 (PAGE_CACHE_SHIFT - inode->i_blkbits);
2140 while (index <= end) {
2141 nr_pages = pagevec_lookup(&pvec, mapping, index, PAGEVEC_SIZE);
2144 for (i = 0; i < nr_pages; i++) {
2145 struct page *page = pvec.pages[i];
2146 index = page->index;
2151 BUG_ON(!PageLocked(page));
2152 BUG_ON(PageWriteback(page));
2153 block_invalidatepage(page, 0);
2154 ClearPageUptodate(page);
2161 static void ext4_print_free_blocks(struct inode *inode)
2163 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2164 printk(KERN_CRIT "Total free blocks count %lld\n",
2165 ext4_count_free_blocks(inode->i_sb));
2166 printk(KERN_CRIT "Free/Dirty block details\n");
2167 printk(KERN_CRIT "free_blocks=%lld\n",
2168 (long long) percpu_counter_sum(&sbi->s_freeblocks_counter));
2169 printk(KERN_CRIT "dirty_blocks=%lld\n",
2170 (long long) percpu_counter_sum(&sbi->s_dirtyblocks_counter));
2171 printk(KERN_CRIT "Block reservation details\n");
2172 printk(KERN_CRIT "i_reserved_data_blocks=%u\n",
2173 EXT4_I(inode)->i_reserved_data_blocks);
2174 printk(KERN_CRIT "i_reserved_meta_blocks=%u\n",
2175 EXT4_I(inode)->i_reserved_meta_blocks);
2180 * mpage_da_map_blocks - go through given space
2182 * @mpd - bh describing space
2184 * The function skips space we know is already mapped to disk blocks.
2187 static int mpage_da_map_blocks(struct mpage_da_data *mpd)
2189 int err, blks, get_blocks_flags;
2190 struct buffer_head new;
2191 sector_t next = mpd->b_blocknr;
2192 unsigned max_blocks = mpd->b_size >> mpd->inode->i_blkbits;
2193 loff_t disksize = EXT4_I(mpd->inode)->i_disksize;
2194 handle_t *handle = NULL;
2197 * We consider only non-mapped and non-allocated blocks
2199 if ((mpd->b_state & (1 << BH_Mapped)) &&
2200 !(mpd->b_state & (1 << BH_Delay)) &&
2201 !(mpd->b_state & (1 << BH_Unwritten)))
2205 * If we didn't accumulate anything to write simply return
2210 handle = ext4_journal_current_handle();
2214 * Call ext4_get_blocks() to allocate any delayed allocation
2215 * blocks, or to convert an uninitialized extent to be
2216 * initialized (in the case where we have written into
2217 * one or more preallocated blocks).
2219 * We pass in the magic EXT4_GET_BLOCKS_DELALLOC_RESERVE to
2220 * indicate that we are on the delayed allocation path. This
2221 * affects functions in many different parts of the allocation
2222 * call path. This flag exists primarily because we don't
2223 * want to change *many* call functions, so ext4_get_blocks()
2224 * will set the magic i_delalloc_reserved_flag once the
2225 * inode's allocation semaphore is taken.
2227 * If the blocks in questions were delalloc blocks, set
2228 * EXT4_GET_BLOCKS_DELALLOC_RESERVE so the delalloc accounting
2229 * variables are updated after the blocks have been allocated.
2232 get_blocks_flags = EXT4_GET_BLOCKS_CREATE;
2233 if (ext4_should_dioread_nolock(mpd->inode))
2234 get_blocks_flags |= EXT4_GET_BLOCKS_IO_CREATE_EXT;
2235 if (mpd->b_state & (1 << BH_Delay))
2236 get_blocks_flags |= EXT4_GET_BLOCKS_DELALLOC_RESERVE;
2238 blks = ext4_get_blocks(handle, mpd->inode, next, max_blocks,
2239 &new, get_blocks_flags);
2243 * If get block returns with error we simply
2244 * return. Later writepage will redirty the page and
2245 * writepages will find the dirty page again
2250 if (err == -ENOSPC &&
2251 ext4_count_free_blocks(mpd->inode->i_sb)) {
2257 * get block failure will cause us to loop in
2258 * writepages, because a_ops->writepage won't be able
2259 * to make progress. The page will be redirtied by
2260 * writepage and writepages will again try to write
2263 ext4_msg(mpd->inode->i_sb, KERN_CRIT,
2264 "delayed block allocation failed for inode %lu at "
2265 "logical offset %llu with max blocks %zd with "
2266 "error %d\n", mpd->inode->i_ino,
2267 (unsigned long long) next,
2268 mpd->b_size >> mpd->inode->i_blkbits, err);
2269 printk(KERN_CRIT "This should not happen!! "
2270 "Data will be lost\n");
2271 if (err == -ENOSPC) {
2272 ext4_print_free_blocks(mpd->inode);
2274 /* invalidate all the pages */
2275 ext4_da_block_invalidatepages(mpd, next,
2276 mpd->b_size >> mpd->inode->i_blkbits);
2281 new.b_size = (blks << mpd->inode->i_blkbits);
2283 if (buffer_new(&new))
2284 __unmap_underlying_blocks(mpd->inode, &new);
2287 * If blocks are delayed marked, we need to
2288 * put actual blocknr and drop delayed bit
2290 if ((mpd->b_state & (1 << BH_Delay)) ||
2291 (mpd->b_state & (1 << BH_Unwritten)))
2292 mpage_put_bnr_to_bhs(mpd, next, &new);
2294 if (ext4_should_order_data(mpd->inode)) {
2295 err = ext4_jbd2_file_inode(handle, mpd->inode);
2301 * Update on-disk size along with block allocation.
2303 disksize = ((loff_t) next + blks) << mpd->inode->i_blkbits;
2304 if (disksize > i_size_read(mpd->inode))
2305 disksize = i_size_read(mpd->inode);
2306 if (disksize > EXT4_I(mpd->inode)->i_disksize) {
2307 ext4_update_i_disksize(mpd->inode, disksize);
2308 return ext4_mark_inode_dirty(handle, mpd->inode);
2314 #define BH_FLAGS ((1 << BH_Uptodate) | (1 << BH_Mapped) | \
2315 (1 << BH_Delay) | (1 << BH_Unwritten))
2318 * mpage_add_bh_to_extent - try to add one more block to extent of blocks
2320 * @mpd->lbh - extent of blocks
2321 * @logical - logical number of the block in the file
2322 * @bh - bh of the block (used to access block's state)
2324 * the function is used to collect contig. blocks in same state
2326 static void mpage_add_bh_to_extent(struct mpage_da_data *mpd,
2327 sector_t logical, size_t b_size,
2328 unsigned long b_state)
2331 int nrblocks = mpd->b_size >> mpd->inode->i_blkbits;
2333 /* check if thereserved journal credits might overflow */
2334 if (!(EXT4_I(mpd->inode)->i_flags & EXT4_EXTENTS_FL)) {
2335 if (nrblocks >= EXT4_MAX_TRANS_DATA) {
2337 * With non-extent format we are limited by the journal
2338 * credit available. Total credit needed to insert
2339 * nrblocks contiguous blocks is dependent on the
2340 * nrblocks. So limit nrblocks.
2343 } else if ((nrblocks + (b_size >> mpd->inode->i_blkbits)) >
2344 EXT4_MAX_TRANS_DATA) {
2346 * Adding the new buffer_head would make it cross the
2347 * allowed limit for which we have journal credit
2348 * reserved. So limit the new bh->b_size
2350 b_size = (EXT4_MAX_TRANS_DATA - nrblocks) <<
2351 mpd->inode->i_blkbits;
2352 /* we will do mpage_da_submit_io in the next loop */
2356 * First block in the extent
2358 if (mpd->b_size == 0) {
2359 mpd->b_blocknr = logical;
2360 mpd->b_size = b_size;
2361 mpd->b_state = b_state & BH_FLAGS;
2365 next = mpd->b_blocknr + nrblocks;
2367 * Can we merge the block to our big extent?
2369 if (logical == next && (b_state & BH_FLAGS) == mpd->b_state) {
2370 mpd->b_size += b_size;
2376 * We couldn't merge the block to our extent, so we
2377 * need to flush current extent and start new one
2379 if (mpage_da_map_blocks(mpd) == 0)
2380 mpage_da_submit_io(mpd);
2385 static int ext4_bh_delay_or_unwritten(handle_t *handle, struct buffer_head *bh)
2387 return (buffer_delay(bh) || buffer_unwritten(bh)) && buffer_dirty(bh);
2391 * __mpage_da_writepage - finds extent of pages and blocks
2393 * @page: page to consider
2394 * @wbc: not used, we just follow rules
2397 * The function finds extents of pages and scan them for all blocks.
2399 static int __mpage_da_writepage(struct page *page,
2400 struct writeback_control *wbc, void *data)
2402 struct mpage_da_data *mpd = data;
2403 struct inode *inode = mpd->inode;
2404 struct buffer_head *bh, *head;
2409 * Rest of the page in the page_vec
2410 * redirty then and skip then. We will
2411 * try to write them again after
2412 * starting a new transaction
2414 redirty_page_for_writepage(wbc, page);
2416 return MPAGE_DA_EXTENT_TAIL;
2419 * Can we merge this page to current extent?
2421 if (mpd->next_page != page->index) {
2423 * Nope, we can't. So, we map non-allocated blocks
2424 * and start IO on them using writepage()
2426 if (mpd->next_page != mpd->first_page) {
2427 if (mpage_da_map_blocks(mpd) == 0)
2428 mpage_da_submit_io(mpd);
2430 * skip rest of the page in the page_vec
2433 redirty_page_for_writepage(wbc, page);
2435 return MPAGE_DA_EXTENT_TAIL;
2439 * Start next extent of pages ...
2441 mpd->first_page = page->index;
2451 mpd->next_page = page->index + 1;
2452 logical = (sector_t) page->index <<
2453 (PAGE_CACHE_SHIFT - inode->i_blkbits);
2455 if (!page_has_buffers(page)) {
2456 mpage_add_bh_to_extent(mpd, logical, PAGE_CACHE_SIZE,
2457 (1 << BH_Dirty) | (1 << BH_Uptodate));
2459 return MPAGE_DA_EXTENT_TAIL;
2462 * Page with regular buffer heads, just add all dirty ones
2464 head = page_buffers(page);
2467 BUG_ON(buffer_locked(bh));
2469 * We need to try to allocate
2470 * unmapped blocks in the same page.
2471 * Otherwise we won't make progress
2472 * with the page in ext4_writepage
2474 if (ext4_bh_delay_or_unwritten(NULL, bh)) {
2475 mpage_add_bh_to_extent(mpd, logical,
2479 return MPAGE_DA_EXTENT_TAIL;
2480 } else if (buffer_dirty(bh) && (buffer_mapped(bh))) {
2482 * mapped dirty buffer. We need to update
2483 * the b_state because we look at
2484 * b_state in mpage_da_map_blocks. We don't
2485 * update b_size because if we find an
2486 * unmapped buffer_head later we need to
2487 * use the b_state flag of that buffer_head.
2489 if (mpd->b_size == 0)
2490 mpd->b_state = bh->b_state & BH_FLAGS;
2493 } while ((bh = bh->b_this_page) != head);
2500 * This is a special get_blocks_t callback which is used by
2501 * ext4_da_write_begin(). It will either return mapped block or
2502 * reserve space for a single block.
2504 * For delayed buffer_head we have BH_Mapped, BH_New, BH_Delay set.
2505 * We also have b_blocknr = -1 and b_bdev initialized properly
2507 * For unwritten buffer_head we have BH_Mapped, BH_New, BH_Unwritten set.
2508 * We also have b_blocknr = physicalblock mapping unwritten extent and b_bdev
2509 * initialized properly.
2511 static int ext4_da_get_block_prep(struct inode *inode, sector_t iblock,
2512 struct buffer_head *bh_result, int create)
2515 sector_t invalid_block = ~((sector_t) 0xffff);
2517 if (invalid_block < ext4_blocks_count(EXT4_SB(inode->i_sb)->s_es))
2520 BUG_ON(create == 0);
2521 BUG_ON(bh_result->b_size != inode->i_sb->s_blocksize);
2524 * first, we need to know whether the block is allocated already
2525 * preallocated blocks are unmapped but should treated
2526 * the same as allocated blocks.
2528 ret = ext4_get_blocks(NULL, inode, iblock, 1, bh_result, 0);
2529 if ((ret == 0) && !buffer_delay(bh_result)) {
2530 /* the block isn't (pre)allocated yet, let's reserve space */
2532 * XXX: __block_prepare_write() unmaps passed block,
2535 ret = ext4_da_reserve_space(inode, iblock);
2537 /* not enough space to reserve */
2540 map_bh(bh_result, inode->i_sb, invalid_block);
2541 set_buffer_new(bh_result);
2542 set_buffer_delay(bh_result);
2543 } else if (ret > 0) {
2544 bh_result->b_size = (ret << inode->i_blkbits);
2545 if (buffer_unwritten(bh_result)) {
2546 /* A delayed write to unwritten bh should
2547 * be marked new and mapped. Mapped ensures
2548 * that we don't do get_block multiple times
2549 * when we write to the same offset and new
2550 * ensures that we do proper zero out for
2553 set_buffer_new(bh_result);
2554 set_buffer_mapped(bh_result);
2563 * This function is used as a standard get_block_t calback function
2564 * when there is no desire to allocate any blocks. It is used as a
2565 * callback function for block_prepare_write(), nobh_writepage(), and
2566 * block_write_full_page(). These functions should only try to map a
2567 * single block at a time.
2569 * Since this function doesn't do block allocations even if the caller
2570 * requests it by passing in create=1, it is critically important that
2571 * any caller checks to make sure that any buffer heads are returned
2572 * by this function are either all already mapped or marked for
2573 * delayed allocation before calling nobh_writepage() or
2574 * block_write_full_page(). Otherwise, b_blocknr could be left
2575 * unitialized, and the page write functions will be taken by
2578 static int noalloc_get_block_write(struct inode *inode, sector_t iblock,
2579 struct buffer_head *bh_result, int create)
2582 unsigned max_blocks = bh_result->b_size >> inode->i_blkbits;
2584 BUG_ON(bh_result->b_size != inode->i_sb->s_blocksize);
2587 * we don't want to do block allocation in writepage
2588 * so call get_block_wrap with create = 0
2590 ret = ext4_get_blocks(NULL, inode, iblock, max_blocks, bh_result, 0);
2592 bh_result->b_size = (ret << inode->i_blkbits);
2598 static int bget_one(handle_t *handle, struct buffer_head *bh)
2604 static int bput_one(handle_t *handle, struct buffer_head *bh)
2610 static int __ext4_journalled_writepage(struct page *page,
2613 struct address_space *mapping = page->mapping;
2614 struct inode *inode = mapping->host;
2615 struct buffer_head *page_bufs;
2616 handle_t *handle = NULL;
2620 page_bufs = page_buffers(page);
2622 walk_page_buffers(handle, page_bufs, 0, len, NULL, bget_one);
2623 /* As soon as we unlock the page, it can go away, but we have
2624 * references to buffers so we are safe */
2627 handle = ext4_journal_start(inode, ext4_writepage_trans_blocks(inode));
2628 if (IS_ERR(handle)) {
2629 ret = PTR_ERR(handle);
2633 ret = walk_page_buffers(handle, page_bufs, 0, len, NULL,
2634 do_journal_get_write_access);
2636 err = walk_page_buffers(handle, page_bufs, 0, len, NULL,
2640 err = ext4_journal_stop(handle);
2644 walk_page_buffers(handle, page_bufs, 0, len, NULL, bput_one);
2645 ext4_set_inode_state(inode, EXT4_STATE_JDATA);
2650 static int ext4_set_bh_endio(struct buffer_head *bh, struct inode *inode);
2651 static void ext4_end_io_buffer_write(struct buffer_head *bh, int uptodate);
2654 * Note that we don't need to start a transaction unless we're journaling data
2655 * because we should have holes filled from ext4_page_mkwrite(). We even don't
2656 * need to file the inode to the transaction's list in ordered mode because if
2657 * we are writing back data added by write(), the inode is already there and if
2658 * we are writing back data modified via mmap(), noone guarantees in which
2659 * transaction the data will hit the disk. In case we are journaling data, we
2660 * cannot start transaction directly because transaction start ranks above page
2661 * lock so we have to do some magic.
2663 * This function can get called via...
2664 * - ext4_da_writepages after taking page lock (have journal handle)
2665 * - journal_submit_inode_data_buffers (no journal handle)
2666 * - shrink_page_list via pdflush (no journal handle)
2667 * - grab_page_cache when doing write_begin (have journal handle)
2669 * We don't do any block allocation in this function. If we have page with
2670 * multiple blocks we need to write those buffer_heads that are mapped. This
2671 * is important for mmaped based write. So if we do with blocksize 1K
2672 * truncate(f, 1024);
2673 * a = mmap(f, 0, 4096);
2675 * truncate(f, 4096);
2676 * we have in the page first buffer_head mapped via page_mkwrite call back
2677 * but other bufer_heads would be unmapped but dirty(dirty done via the
2678 * do_wp_page). So writepage should write the first block. If we modify
2679 * the mmap area beyond 1024 we will again get a page_fault and the
2680 * page_mkwrite callback will do the block allocation and mark the
2681 * buffer_heads mapped.
2683 * We redirty the page if we have any buffer_heads that is either delay or
2684 * unwritten in the page.
2686 * We can get recursively called as show below.
2688 * ext4_writepage() -> kmalloc() -> __alloc_pages() -> page_launder() ->
2691 * But since we don't do any block allocation we should not deadlock.
2692 * Page also have the dirty flag cleared so we don't get recurive page_lock.
2694 static int ext4_writepage(struct page *page,
2695 struct writeback_control *wbc)
2700 struct buffer_head *page_bufs = NULL;
2701 struct inode *inode = page->mapping->host;
2703 trace_ext4_writepage(inode, page);
2704 size = i_size_read(inode);
2705 if (page->index == size >> PAGE_CACHE_SHIFT)
2706 len = size & ~PAGE_CACHE_MASK;
2708 len = PAGE_CACHE_SIZE;
2710 if (page_has_buffers(page)) {
2711 page_bufs = page_buffers(page);
2712 if (walk_page_buffers(NULL, page_bufs, 0, len, NULL,
2713 ext4_bh_delay_or_unwritten)) {
2715 * We don't want to do block allocation
2716 * So redirty the page and return
2717 * We may reach here when we do a journal commit
2718 * via journal_submit_inode_data_buffers.
2719 * If we don't have mapping block we just ignore
2720 * them. We can also reach here via shrink_page_list
2722 redirty_page_for_writepage(wbc, page);
2728 * The test for page_has_buffers() is subtle:
2729 * We know the page is dirty but it lost buffers. That means
2730 * that at some moment in time after write_begin()/write_end()
2731 * has been called all buffers have been clean and thus they
2732 * must have been written at least once. So they are all
2733 * mapped and we can happily proceed with mapping them
2734 * and writing the page.
2736 * Try to initialize the buffer_heads and check whether
2737 * all are mapped and non delay. We don't want to
2738 * do block allocation here.
2740 ret = block_prepare_write(page, 0, len,
2741 noalloc_get_block_write);
2743 page_bufs = page_buffers(page);
2744 /* check whether all are mapped and non delay */
2745 if (walk_page_buffers(NULL, page_bufs, 0, len, NULL,
2746 ext4_bh_delay_or_unwritten)) {
2747 redirty_page_for_writepage(wbc, page);
2753 * We can't do block allocation here
2754 * so just redity the page and unlock
2757 redirty_page_for_writepage(wbc, page);
2761 /* now mark the buffer_heads as dirty and uptodate */
2762 block_commit_write(page, 0, len);
2765 if (PageChecked(page) && ext4_should_journal_data(inode)) {
2767 * It's mmapped pagecache. Add buffers and journal it. There
2768 * doesn't seem much point in redirtying the page here.
2770 ClearPageChecked(page);
2771 return __ext4_journalled_writepage(page, len);
2774 if (test_opt(inode->i_sb, NOBH) && ext4_should_writeback_data(inode))
2775 ret = nobh_writepage(page, noalloc_get_block_write, wbc);
2776 else if (page_bufs && buffer_uninit(page_bufs)) {
2777 ext4_set_bh_endio(page_bufs, inode);
2778 ret = block_write_full_page_endio(page, noalloc_get_block_write,
2779 wbc, ext4_end_io_buffer_write);
2781 ret = block_write_full_page(page, noalloc_get_block_write,
2788 * This is called via ext4_da_writepages() to
2789 * calulate the total number of credits to reserve to fit
2790 * a single extent allocation into a single transaction,
2791 * ext4_da_writpeages() will loop calling this before
2792 * the block allocation.
2795 static int ext4_da_writepages_trans_blocks(struct inode *inode)
2797 int max_blocks = EXT4_I(inode)->i_reserved_data_blocks;
2800 * With non-extent format the journal credit needed to
2801 * insert nrblocks contiguous block is dependent on
2802 * number of contiguous block. So we will limit
2803 * number of contiguous block to a sane value
2805 if (!(EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL) &&
2806 (max_blocks > EXT4_MAX_TRANS_DATA))
2807 max_blocks = EXT4_MAX_TRANS_DATA;
2809 return ext4_chunk_trans_blocks(inode, max_blocks);
2812 static int ext4_da_writepages(struct address_space *mapping,
2813 struct writeback_control *wbc)
2816 int range_whole = 0;
2817 handle_t *handle = NULL;
2818 struct mpage_da_data mpd;
2819 struct inode *inode = mapping->host;
2820 int no_nrwrite_index_update;
2821 int pages_written = 0;
2823 unsigned int max_pages;
2824 int range_cyclic, cycled = 1, io_done = 0;
2825 int needed_blocks, ret = 0;
2826 long desired_nr_to_write, nr_to_writebump = 0;
2827 loff_t range_start = wbc->range_start;
2828 struct ext4_sb_info *sbi = EXT4_SB(mapping->host->i_sb);
2830 trace_ext4_da_writepages(inode, wbc);
2833 * No pages to write? This is mainly a kludge to avoid starting
2834 * a transaction for special inodes like journal inode on last iput()
2835 * because that could violate lock ordering on umount
2837 if (!mapping->nrpages || !mapping_tagged(mapping, PAGECACHE_TAG_DIRTY))
2841 * If the filesystem has aborted, it is read-only, so return
2842 * right away instead of dumping stack traces later on that
2843 * will obscure the real source of the problem. We test
2844 * EXT4_MF_FS_ABORTED instead of sb->s_flag's MS_RDONLY because
2845 * the latter could be true if the filesystem is mounted
2846 * read-only, and in that case, ext4_da_writepages should
2847 * *never* be called, so if that ever happens, we would want
2850 if (unlikely(sbi->s_mount_flags & EXT4_MF_FS_ABORTED))
2853 if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX)
2856 range_cyclic = wbc->range_cyclic;
2857 if (wbc->range_cyclic) {
2858 index = mapping->writeback_index;
2861 wbc->range_start = index << PAGE_CACHE_SHIFT;
2862 wbc->range_end = LLONG_MAX;
2863 wbc->range_cyclic = 0;
2865 index = wbc->range_start >> PAGE_CACHE_SHIFT;
2868 * This works around two forms of stupidity. The first is in
2869 * the writeback code, which caps the maximum number of pages
2870 * written to be 1024 pages. This is wrong on multiple
2871 * levels; different architectues have a different page size,
2872 * which changes the maximum amount of data which gets
2873 * written. Secondly, 4 megabytes is way too small. XFS
2874 * forces this value to be 16 megabytes by multiplying
2875 * nr_to_write parameter by four, and then relies on its
2876 * allocator to allocate larger extents to make them
2877 * contiguous. Unfortunately this brings us to the second
2878 * stupidity, which is that ext4's mballoc code only allocates
2879 * at most 2048 blocks. So we force contiguous writes up to
2880 * the number of dirty blocks in the inode, or
2881 * sbi->max_writeback_mb_bump whichever is smaller.
2883 max_pages = sbi->s_max_writeback_mb_bump << (20 - PAGE_CACHE_SHIFT);
2884 if (!range_cyclic && range_whole)
2885 desired_nr_to_write = wbc->nr_to_write * 8;
2887 desired_nr_to_write = ext4_num_dirty_pages(inode, index,
2889 if (desired_nr_to_write > max_pages)
2890 desired_nr_to_write = max_pages;
2892 if (wbc->nr_to_write < desired_nr_to_write) {
2893 nr_to_writebump = desired_nr_to_write - wbc->nr_to_write;
2894 wbc->nr_to_write = desired_nr_to_write;
2898 mpd.inode = mapping->host;
2901 * we don't want write_cache_pages to update
2902 * nr_to_write and writeback_index
2904 no_nrwrite_index_update = wbc->no_nrwrite_index_update;
2905 wbc->no_nrwrite_index_update = 1;
2906 pages_skipped = wbc->pages_skipped;
2909 while (!ret && wbc->nr_to_write > 0) {
2912 * we insert one extent at a time. So we need
2913 * credit needed for single extent allocation.
2914 * journalled mode is currently not supported
2917 BUG_ON(ext4_should_journal_data(inode));
2918 needed_blocks = ext4_da_writepages_trans_blocks(inode);
2920 /* start a new transaction*/
2921 handle = ext4_journal_start(inode, needed_blocks);
2922 if (IS_ERR(handle)) {
2923 ret = PTR_ERR(handle);
2924 ext4_msg(inode->i_sb, KERN_CRIT, "%s: jbd2_start: "
2925 "%ld pages, ino %lu; err %d\n", __func__,
2926 wbc->nr_to_write, inode->i_ino, ret);
2927 goto out_writepages;
2931 * Now call __mpage_da_writepage to find the next
2932 * contiguous region of logical blocks that need
2933 * blocks to be allocated by ext4. We don't actually
2934 * submit the blocks for I/O here, even though
2935 * write_cache_pages thinks it will, and will set the
2936 * pages as clean for write before calling
2937 * __mpage_da_writepage().
2945 mpd.pages_written = 0;
2947 ret = write_cache_pages(mapping, wbc, __mpage_da_writepage,
2950 * If we have a contiguous extent of pages and we
2951 * haven't done the I/O yet, map the blocks and submit
2954 if (!mpd.io_done && mpd.next_page != mpd.first_page) {
2955 if (mpage_da_map_blocks(&mpd) == 0)
2956 mpage_da_submit_io(&mpd);
2958 ret = MPAGE_DA_EXTENT_TAIL;
2960 trace_ext4_da_write_pages(inode, &mpd);
2961 wbc->nr_to_write -= mpd.pages_written;
2963 ext4_journal_stop(handle);
2965 if ((mpd.retval == -ENOSPC) && sbi->s_journal) {
2966 /* commit the transaction which would
2967 * free blocks released in the transaction
2970 jbd2_journal_force_commit_nested(sbi->s_journal);
2971 wbc->pages_skipped = pages_skipped;
2973 } else if (ret == MPAGE_DA_EXTENT_TAIL) {
2975 * got one extent now try with
2978 pages_written += mpd.pages_written;
2979 wbc->pages_skipped = pages_skipped;
2982 } else if (wbc->nr_to_write)
2984 * There is no more writeout needed
2985 * or we requested for a noblocking writeout
2986 * and we found the device congested
2990 if (!io_done && !cycled) {
2993 wbc->range_start = index << PAGE_CACHE_SHIFT;
2994 wbc->range_end = mapping->writeback_index - 1;
2997 if (pages_skipped != wbc->pages_skipped)
2998 ext4_msg(inode->i_sb, KERN_CRIT,
2999 "This should not happen leaving %s "
3000 "with nr_to_write = %ld ret = %d\n",
3001 __func__, wbc->nr_to_write, ret);
3004 index += pages_written;
3005 wbc->range_cyclic = range_cyclic;
3006 if (wbc->range_cyclic || (range_whole && wbc->nr_to_write > 0))
3008 * set the writeback_index so that range_cyclic
3009 * mode will write it back later
3011 mapping->writeback_index = index;
3014 if (!no_nrwrite_index_update)
3015 wbc->no_nrwrite_index_update = 0;
3016 wbc->nr_to_write -= nr_to_writebump;
3017 wbc->range_start = range_start;
3018 trace_ext4_da_writepages_result(inode, wbc, ret, pages_written);
3022 #define FALL_BACK_TO_NONDELALLOC 1
3023 static int ext4_nonda_switch(struct super_block *sb)
3025 s64 free_blocks, dirty_blocks;
3026 struct ext4_sb_info *sbi = EXT4_SB(sb);
3029 * switch to non delalloc mode if we are running low
3030 * on free block. The free block accounting via percpu
3031 * counters can get slightly wrong with percpu_counter_batch getting
3032 * accumulated on each CPU without updating global counters
3033 * Delalloc need an accurate free block accounting. So switch
3034 * to non delalloc when we are near to error range.
3036 free_blocks = percpu_counter_read_positive(&sbi->s_freeblocks_counter);
3037 dirty_blocks = percpu_counter_read_positive(&sbi->s_dirtyblocks_counter);
3038 if (2 * free_blocks < 3 * dirty_blocks ||
3039 free_blocks < (dirty_blocks + EXT4_FREEBLOCKS_WATERMARK)) {
3041 * free block count is less than 150% of dirty blocks
3042 * or free blocks is less than watermark
3047 * Even if we don't switch but are nearing capacity,
3048 * start pushing delalloc when 1/2 of free blocks are dirty.
3050 if (free_blocks < 2 * dirty_blocks)
3051 writeback_inodes_sb_if_idle(sb);
3056 static int ext4_da_write_begin(struct file *file, struct address_space *mapping,
3057 loff_t pos, unsigned len, unsigned flags,
3058 struct page **pagep, void **fsdata)
3060 int ret, retries = 0, quota_retries = 0;
3064 struct inode *inode = mapping->host;
3067 index = pos >> PAGE_CACHE_SHIFT;
3068 from = pos & (PAGE_CACHE_SIZE - 1);
3071 if (ext4_nonda_switch(inode->i_sb)) {
3072 *fsdata = (void *)FALL_BACK_TO_NONDELALLOC;
3073 return ext4_write_begin(file, mapping, pos,
3074 len, flags, pagep, fsdata);
3076 *fsdata = (void *)0;
3077 trace_ext4_da_write_begin(inode, pos, len, flags);
3080 * With delayed allocation, we don't log the i_disksize update
3081 * if there is delayed block allocation. But we still need
3082 * to journalling the i_disksize update if writes to the end
3083 * of file which has an already mapped buffer.
3085 handle = ext4_journal_start(inode, 1);
3086 if (IS_ERR(handle)) {
3087 ret = PTR_ERR(handle);
3090 /* We cannot recurse into the filesystem as the transaction is already
3092 flags |= AOP_FLAG_NOFS;
3094 page = grab_cache_page_write_begin(mapping, index, flags);
3096 ext4_journal_stop(handle);
3102 ret = block_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
3103 ext4_da_get_block_prep);
3106 ext4_journal_stop(handle);
3107 page_cache_release(page);
3109 * block_write_begin may have instantiated a few blocks
3110 * outside i_size. Trim these off again. Don't need
3111 * i_size_read because we hold i_mutex.
3113 if (pos + len > inode->i_size)
3114 ext4_truncate_failed_write(inode);
3117 if (ret == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
3120 if ((ret == -EDQUOT) &&
3121 EXT4_I(inode)->i_reserved_meta_blocks &&
3122 (quota_retries++ < 3)) {
3124 * Since we often over-estimate the number of meta
3125 * data blocks required, we may sometimes get a
3126 * spurios out of quota error even though there would
3127 * be enough space once we write the data blocks and
3128 * find out how many meta data blocks were _really_
3129 * required. So try forcing the inode write to see if
3132 write_inode_now(inode, (quota_retries == 3));
3140 * Check if we should update i_disksize
3141 * when write to the end of file but not require block allocation
3143 static int ext4_da_should_update_i_disksize(struct page *page,
3144 unsigned long offset)
3146 struct buffer_head *bh;
3147 struct inode *inode = page->mapping->host;
3151 bh = page_buffers(page);
3152 idx = offset >> inode->i_blkbits;
3154 for (i = 0; i < idx; i++)
3155 bh = bh->b_this_page;
3157 if (!buffer_mapped(bh) || (buffer_delay(bh)) || buffer_unwritten(bh))
3162 static int ext4_da_write_end(struct file *file,
3163 struct address_space *mapping,
3164 loff_t pos, unsigned len, unsigned copied,
3165 struct page *page, void *fsdata)
3167 struct inode *inode = mapping->host;
3169 handle_t *handle = ext4_journal_current_handle();
3171 unsigned long start, end;
3172 int write_mode = (int)(unsigned long)fsdata;
3174 if (write_mode == FALL_BACK_TO_NONDELALLOC) {
3175 if (ext4_should_order_data(inode)) {
3176 return ext4_ordered_write_end(file, mapping, pos,
3177 len, copied, page, fsdata);
3178 } else if (ext4_should_writeback_data(inode)) {
3179 return ext4_writeback_write_end(file, mapping, pos,
3180 len, copied, page, fsdata);
3186 trace_ext4_da_write_end(inode, pos, len, copied);
3187 start = pos & (PAGE_CACHE_SIZE - 1);
3188 end = start + copied - 1;
3191 * generic_write_end() will run mark_inode_dirty() if i_size
3192 * changes. So let's piggyback the i_disksize mark_inode_dirty
3196 new_i_size = pos + copied;
3197 if (new_i_size > EXT4_I(inode)->i_disksize) {
3198 if (ext4_da_should_update_i_disksize(page, end)) {
3199 down_write(&EXT4_I(inode)->i_data_sem);
3200 if (new_i_size > EXT4_I(inode)->i_disksize) {
3202 * Updating i_disksize when extending file
3203 * without needing block allocation
3205 if (ext4_should_order_data(inode))
3206 ret = ext4_jbd2_file_inode(handle,
3209 EXT4_I(inode)->i_disksize = new_i_size;
3211 up_write(&EXT4_I(inode)->i_data_sem);
3212 /* We need to mark inode dirty even if
3213 * new_i_size is less that inode->i_size
3214 * bu greater than i_disksize.(hint delalloc)
3216 ext4_mark_inode_dirty(handle, inode);
3219 ret2 = generic_write_end(file, mapping, pos, len, copied,
3224 ret2 = ext4_journal_stop(handle);
3228 return ret ? ret : copied;
3231 static void ext4_da_invalidatepage(struct page *page, unsigned long offset)
3234 * Drop reserved blocks
3236 BUG_ON(!PageLocked(page));
3237 if (!page_has_buffers(page))
3240 ext4_da_page_release_reservation(page, offset);
3243 ext4_invalidatepage(page, offset);
3249 * Force all delayed allocation blocks to be allocated for a given inode.
3251 int ext4_alloc_da_blocks(struct inode *inode)
3253 trace_ext4_alloc_da_blocks(inode);
3255 if (!EXT4_I(inode)->i_reserved_data_blocks &&
3256 !EXT4_I(inode)->i_reserved_meta_blocks)
3260 * We do something simple for now. The filemap_flush() will
3261 * also start triggering a write of the data blocks, which is
3262 * not strictly speaking necessary (and for users of
3263 * laptop_mode, not even desirable). However, to do otherwise
3264 * would require replicating code paths in:
3266 * ext4_da_writepages() ->
3267 * write_cache_pages() ---> (via passed in callback function)
3268 * __mpage_da_writepage() -->
3269 * mpage_add_bh_to_extent()
3270 * mpage_da_map_blocks()
3272 * The problem is that write_cache_pages(), located in
3273 * mm/page-writeback.c, marks pages clean in preparation for
3274 * doing I/O, which is not desirable if we're not planning on
3277 * We could call write_cache_pages(), and then redirty all of
3278 * the pages by calling redirty_page_for_writeback() but that
3279 * would be ugly in the extreme. So instead we would need to
3280 * replicate parts of the code in the above functions,
3281 * simplifying them becuase we wouldn't actually intend to
3282 * write out the pages, but rather only collect contiguous
3283 * logical block extents, call the multi-block allocator, and
3284 * then update the buffer heads with the block allocations.
3286 * For now, though, we'll cheat by calling filemap_flush(),
3287 * which will map the blocks, and start the I/O, but not
3288 * actually wait for the I/O to complete.
3290 return filemap_flush(inode->i_mapping);
3294 * bmap() is special. It gets used by applications such as lilo and by
3295 * the swapper to find the on-disk block of a specific piece of data.
3297 * Naturally, this is dangerous if the block concerned is still in the
3298 * journal. If somebody makes a swapfile on an ext4 data-journaling
3299 * filesystem and enables swap, then they may get a nasty shock when the
3300 * data getting swapped to that swapfile suddenly gets overwritten by
3301 * the original zero's written out previously to the journal and
3302 * awaiting writeback in the kernel's buffer cache.
3304 * So, if we see any bmap calls here on a modified, data-journaled file,
3305 * take extra steps to flush any blocks which might be in the cache.
3307 static sector_t ext4_bmap(struct address_space *mapping, sector_t block)
3309 struct inode *inode = mapping->host;
3313 if (mapping_tagged(mapping, PAGECACHE_TAG_DIRTY) &&
3314 test_opt(inode->i_sb, DELALLOC)) {
3316 * With delalloc we want to sync the file
3317 * so that we can make sure we allocate
3320 filemap_write_and_wait(mapping);
3323 if (EXT4_JOURNAL(inode) &&
3324 ext4_test_inode_state(inode, EXT4_STATE_JDATA)) {
3326 * This is a REALLY heavyweight approach, but the use of
3327 * bmap on dirty files is expected to be extremely rare:
3328 * only if we run lilo or swapon on a freshly made file
3329 * do we expect this to happen.
3331 * (bmap requires CAP_SYS_RAWIO so this does not
3332 * represent an unprivileged user DOS attack --- we'd be
3333 * in trouble if mortal users could trigger this path at
3336 * NB. EXT4_STATE_JDATA is not set on files other than
3337 * regular files. If somebody wants to bmap a directory
3338 * or symlink and gets confused because the buffer
3339 * hasn't yet been flushed to disk, they deserve
3340 * everything they get.
3343 ext4_clear_inode_state(inode, EXT4_STATE_JDATA);
3344 journal = EXT4_JOURNAL(inode);
3345 jbd2_journal_lock_updates(journal);
3346 err = jbd2_journal_flush(journal);
3347 jbd2_journal_unlock_updates(journal);
3353 return generic_block_bmap(mapping, block, ext4_get_block);
3356 static int ext4_readpage(struct file *file, struct page *page)
3358 return mpage_readpage(page, ext4_get_block);
3362 ext4_readpages(struct file *file, struct address_space *mapping,
3363 struct list_head *pages, unsigned nr_pages)
3365 return mpage_readpages(mapping, pages, nr_pages, ext4_get_block);
3368 static void ext4_free_io_end(ext4_io_end_t *io)
3377 static void ext4_invalidatepage_free_endio(struct page *page, unsigned long offset)
3379 struct buffer_head *head, *bh;
3380 unsigned int curr_off = 0;
3382 if (!page_has_buffers(page))
3384 head = bh = page_buffers(page);
3386 if (offset <= curr_off && test_clear_buffer_uninit(bh)
3388 ext4_free_io_end(bh->b_private);
3389 bh->b_private = NULL;
3390 bh->b_end_io = NULL;
3392 curr_off = curr_off + bh->b_size;
3393 bh = bh->b_this_page;
3394 } while (bh != head);
3397 static void ext4_invalidatepage(struct page *page, unsigned long offset)
3399 journal_t *journal = EXT4_JOURNAL(page->mapping->host);
3402 * free any io_end structure allocated for buffers to be discarded
3404 if (ext4_should_dioread_nolock(page->mapping->host))
3405 ext4_invalidatepage_free_endio(page, offset);
3407 * If it's a full truncate we just forget about the pending dirtying
3410 ClearPageChecked(page);
3413 jbd2_journal_invalidatepage(journal, page, offset);
3415 block_invalidatepage(page, offset);
3418 static int ext4_releasepage(struct page *page, gfp_t wait)
3420 journal_t *journal = EXT4_JOURNAL(page->mapping->host);
3422 WARN_ON(PageChecked(page));
3423 if (!page_has_buffers(page))
3426 return jbd2_journal_try_to_free_buffers(journal, page, wait);
3428 return try_to_free_buffers(page);
3432 * O_DIRECT for ext3 (or indirect map) based files
3434 * If the O_DIRECT write will extend the file then add this inode to the
3435 * orphan list. So recovery will truncate it back to the original size
3436 * if the machine crashes during the write.
3438 * If the O_DIRECT write is intantiating holes inside i_size and the machine
3439 * crashes then stale disk data _may_ be exposed inside the file. But current
3440 * VFS code falls back into buffered path in that case so we are safe.
3442 static ssize_t ext4_ind_direct_IO(int rw, struct kiocb *iocb,
3443 const struct iovec *iov, loff_t offset,
3444 unsigned long nr_segs)
3446 struct file *file = iocb->ki_filp;
3447 struct inode *inode = file->f_mapping->host;
3448 struct ext4_inode_info *ei = EXT4_I(inode);
3452 size_t count = iov_length(iov, nr_segs);
3456 loff_t final_size = offset + count;
3458 if (final_size > inode->i_size) {
3459 /* Credits for sb + inode write */
3460 handle = ext4_journal_start(inode, 2);
3461 if (IS_ERR(handle)) {
3462 ret = PTR_ERR(handle);
3465 ret = ext4_orphan_add(handle, inode);
3467 ext4_journal_stop(handle);
3471 ei->i_disksize = inode->i_size;
3472 ext4_journal_stop(handle);
3477 ret = blockdev_direct_IO(rw, iocb, inode, inode->i_sb->s_bdev, iov,
3479 ext4_get_block, NULL);
3480 if (ret == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
3486 /* Credits for sb + inode write */
3487 handle = ext4_journal_start(inode, 2);
3488 if (IS_ERR(handle)) {
3489 /* This is really bad luck. We've written the data
3490 * but cannot extend i_size. Bail out and pretend
3491 * the write failed... */
3492 ret = PTR_ERR(handle);
3494 ext4_orphan_del(NULL, inode);
3499 ext4_orphan_del(handle, inode);
3501 loff_t end = offset + ret;
3502 if (end > inode->i_size) {
3503 ei->i_disksize = end;
3504 i_size_write(inode, end);
3506 * We're going to return a positive `ret'
3507 * here due to non-zero-length I/O, so there's
3508 * no way of reporting error returns from
3509 * ext4_mark_inode_dirty() to userspace. So
3512 ext4_mark_inode_dirty(handle, inode);
3515 err = ext4_journal_stop(handle);
3523 static int ext4_get_block_write(struct inode *inode, sector_t iblock,
3524 struct buffer_head *bh_result, int create)
3526 handle_t *handle = ext4_journal_current_handle();
3528 unsigned max_blocks = bh_result->b_size >> inode->i_blkbits;
3532 ext4_debug("ext4_get_block_write: inode %lu, create flag %d\n",
3533 inode->i_ino, create);
3535 * ext4_get_block in prepare for a DIO write or buffer write.
3536 * We allocate an uinitialized extent if blocks haven't been allocated.
3537 * The extent will be converted to initialized after IO complete.
3539 create = EXT4_GET_BLOCKS_IO_CREATE_EXT;
3542 if (max_blocks > DIO_MAX_BLOCKS)
3543 max_blocks = DIO_MAX_BLOCKS;
3544 dio_credits = ext4_chunk_trans_blocks(inode, max_blocks);
3545 handle = ext4_journal_start(inode, dio_credits);
3546 if (IS_ERR(handle)) {
3547 ret = PTR_ERR(handle);
3553 ret = ext4_get_blocks(handle, inode, iblock, max_blocks, bh_result,
3556 bh_result->b_size = (ret << inode->i_blkbits);
3560 ext4_journal_stop(handle);
3565 static void dump_completed_IO(struct inode * inode)
3568 struct list_head *cur, *before, *after;
3569 ext4_io_end_t *io, *io0, *io1;
3570 unsigned long flags;
3572 if (list_empty(&EXT4_I(inode)->i_completed_io_list)){
3573 ext4_debug("inode %lu completed_io list is empty\n", inode->i_ino);
3577 ext4_debug("Dump inode %lu completed_io list \n", inode->i_ino);
3578 spin_lock_irqsave(&EXT4_I(inode)->i_completed_io_lock, flags);
3579 list_for_each_entry(io, &EXT4_I(inode)->i_completed_io_list, list){
3582 io0 = container_of(before, ext4_io_end_t, list);
3584 io1 = container_of(after, ext4_io_end_t, list);
3586 ext4_debug("io 0x%p from inode %lu,prev 0x%p,next 0x%p\n",
3587 io, inode->i_ino, io0, io1);
3589 spin_unlock_irqrestore(&EXT4_I(inode)->i_completed_io_lock, flags);
3594 * check a range of space and convert unwritten extents to written.
3596 static int ext4_end_io_nolock(ext4_io_end_t *io)
3598 struct inode *inode = io->inode;
3599 loff_t offset = io->offset;
3600 ssize_t size = io->size;
3603 ext4_debug("ext4_end_io_nolock: io 0x%p from inode %lu,list->next 0x%p,"
3604 "list->prev 0x%p\n",
3605 io, inode->i_ino, io->list.next, io->list.prev);
3607 if (list_empty(&io->list))
3610 if (io->flag != EXT4_IO_UNWRITTEN)
3613 ret = ext4_convert_unwritten_extents(inode, offset, size);
3615 printk(KERN_EMERG "%s: failed to convert unwritten"
3616 "extents to written extents, error is %d"
3617 " io is still on inode %lu aio dio list\n",
3618 __func__, ret, inode->i_ino);
3622 /* clear the DIO AIO unwritten flag */
3628 * work on completed aio dio IO, to convert unwritten extents to extents
3630 static void ext4_end_io_work(struct work_struct *work)
3632 ext4_io_end_t *io = container_of(work, ext4_io_end_t, work);
3633 struct inode *inode = io->inode;
3634 struct ext4_inode_info *ei = EXT4_I(inode);
3635 unsigned long flags;
3638 mutex_lock(&inode->i_mutex);
3639 ret = ext4_end_io_nolock(io);
3641 mutex_unlock(&inode->i_mutex);
3645 spin_lock_irqsave(&ei->i_completed_io_lock, flags);
3646 if (!list_empty(&io->list))
3647 list_del_init(&io->list);
3648 spin_unlock_irqrestore(&ei->i_completed_io_lock, flags);
3649 mutex_unlock(&inode->i_mutex);
3650 ext4_free_io_end(io);
3654 * This function is called from ext4_sync_file().
3656 * When IO is completed, the work to convert unwritten extents to
3657 * written is queued on workqueue but may not get immediately
3658 * scheduled. When fsync is called, we need to ensure the
3659 * conversion is complete before fsync returns.
3660 * The inode keeps track of a list of pending/completed IO that
3661 * might needs to do the conversion. This function walks through
3662 * the list and convert the related unwritten extents for completed IO
3664 * The function return the number of pending IOs on success.
3666 int flush_completed_IO(struct inode *inode)
3669 struct ext4_inode_info *ei = EXT4_I(inode);
3670 unsigned long flags;
3674 if (list_empty(&ei->i_completed_io_list))
3677 dump_completed_IO(inode);
3678 spin_lock_irqsave(&ei->i_completed_io_lock, flags);
3679 while (!list_empty(&ei->i_completed_io_list)){
3680 io = list_entry(ei->i_completed_io_list.next,
3681 ext4_io_end_t, list);
3683 * Calling ext4_end_io_nolock() to convert completed
3686 * When ext4_sync_file() is called, run_queue() may already
3687 * about to flush the work corresponding to this io structure.
3688 * It will be upset if it founds the io structure related
3689 * to the work-to-be schedule is freed.
3691 * Thus we need to keep the io structure still valid here after
3692 * convertion finished. The io structure has a flag to
3693 * avoid double converting from both fsync and background work
3696 spin_unlock_irqrestore(&ei->i_completed_io_lock, flags);
3697 ret = ext4_end_io_nolock(io);
3698 spin_lock_irqsave(&ei->i_completed_io_lock, flags);
3702 list_del_init(&io->list);
3704 spin_unlock_irqrestore(&ei->i_completed_io_lock, flags);
3705 return (ret2 < 0) ? ret2 : 0;
3708 static ext4_io_end_t *ext4_init_io_end (struct inode *inode, gfp_t flags)
3710 ext4_io_end_t *io = NULL;
3712 io = kmalloc(sizeof(*io), flags);
3721 INIT_WORK(&io->work, ext4_end_io_work);
3722 INIT_LIST_HEAD(&io->list);
3728 static void ext4_end_io_dio(struct kiocb *iocb, loff_t offset,
3729 ssize_t size, void *private)
3731 ext4_io_end_t *io_end = iocb->private;
3732 struct workqueue_struct *wq;
3733 unsigned long flags;
3734 struct ext4_inode_info *ei;
3736 /* if not async direct IO or dio with 0 bytes write, just return */
3737 if (!io_end || !size)
3740 ext_debug("ext4_end_io_dio(): io_end 0x%p"
3741 "for inode %lu, iocb 0x%p, offset %llu, size %llu\n",
3742 iocb->private, io_end->inode->i_ino, iocb, offset,
3745 /* if not aio dio with unwritten extents, just free io and return */
3746 if (io_end->flag != EXT4_IO_UNWRITTEN){
3747 ext4_free_io_end(io_end);
3748 iocb->private = NULL;
3752 io_end->offset = offset;
3753 io_end->size = size;
3754 io_end->flag = EXT4_IO_UNWRITTEN;
3755 wq = EXT4_SB(io_end->inode->i_sb)->dio_unwritten_wq;
3757 /* queue the work to convert unwritten extents to written */
3758 queue_work(wq, &io_end->work);
3760 /* Add the io_end to per-inode completed aio dio list*/
3761 ei = EXT4_I(io_end->inode);
3762 spin_lock_irqsave(&ei->i_completed_io_lock, flags);
3763 list_add_tail(&io_end->list, &ei->i_completed_io_list);
3764 spin_unlock_irqrestore(&ei->i_completed_io_lock, flags);
3765 iocb->private = NULL;
3768 static void ext4_end_io_buffer_write(struct buffer_head *bh, int uptodate)
3770 ext4_io_end_t *io_end = bh->b_private;
3771 struct workqueue_struct *wq;
3772 struct inode *inode;
3773 unsigned long flags;
3775 if (!test_clear_buffer_uninit(bh) || !io_end)
3778 if (!(io_end->inode->i_sb->s_flags & MS_ACTIVE)) {
3779 printk("sb umounted, discard end_io request for inode %lu\n",
3780 io_end->inode->i_ino);
3781 ext4_free_io_end(io_end);
3785 io_end->flag = EXT4_IO_UNWRITTEN;
3786 inode = io_end->inode;
3788 /* Add the io_end to per-inode completed io list*/
3789 spin_lock_irqsave(&EXT4_I(inode)->i_completed_io_lock, flags);
3790 list_add_tail(&io_end->list, &EXT4_I(inode)->i_completed_io_list);
3791 spin_unlock_irqrestore(&EXT4_I(inode)->i_completed_io_lock, flags);
3793 wq = EXT4_SB(inode->i_sb)->dio_unwritten_wq;
3794 /* queue the work to convert unwritten extents to written */
3795 queue_work(wq, &io_end->work);
3797 bh->b_private = NULL;
3798 bh->b_end_io = NULL;
3799 clear_buffer_uninit(bh);
3800 end_buffer_async_write(bh, uptodate);
3803 static int ext4_set_bh_endio(struct buffer_head *bh, struct inode *inode)
3805 ext4_io_end_t *io_end;
3806 struct page *page = bh->b_page;
3807 loff_t offset = (sector_t)page->index << PAGE_CACHE_SHIFT;
3808 size_t size = bh->b_size;
3811 io_end = ext4_init_io_end(inode, GFP_ATOMIC);
3813 if (printk_ratelimit())
3814 printk(KERN_WARNING "%s: allocation fail\n", __func__);
3818 io_end->offset = offset;
3819 io_end->size = size;
3821 * We need to hold a reference to the page to make sure it
3822 * doesn't get evicted before ext4_end_io_work() has a chance
3823 * to convert the extent from written to unwritten.
3825 io_end->page = page;
3826 get_page(io_end->page);
3828 bh->b_private = io_end;
3829 bh->b_end_io = ext4_end_io_buffer_write;
3834 * For ext4 extent files, ext4 will do direct-io write to holes,
3835 * preallocated extents, and those write extend the file, no need to
3836 * fall back to buffered IO.
3838 * For holes, we fallocate those blocks, mark them as unintialized
3839 * If those blocks were preallocated, we mark sure they are splited, but
3840 * still keep the range to write as unintialized.
3842 * The unwrritten extents will be converted to written when DIO is completed.
3843 * For async direct IO, since the IO may still pending when return, we
3844 * set up an end_io call back function, which will do the convertion
3845 * when async direct IO completed.
3847 * If the O_DIRECT write will extend the file then add this inode to the
3848 * orphan list. So recovery will truncate it back to the original size
3849 * if the machine crashes during the write.
3852 static ssize_t ext4_ext_direct_IO(int rw, struct kiocb *iocb,
3853 const struct iovec *iov, loff_t offset,
3854 unsigned long nr_segs)
3856 struct file *file = iocb->ki_filp;
3857 struct inode *inode = file->f_mapping->host;
3859 size_t count = iov_length(iov, nr_segs);
3861 loff_t final_size = offset + count;
3862 if (rw == WRITE && final_size <= inode->i_size) {
3864 * We could direct write to holes and fallocate.
3866 * Allocated blocks to fill the hole are marked as uninitialized
3867 * to prevent paralel buffered read to expose the stale data
3868 * before DIO complete the data IO.
3870 * As to previously fallocated extents, ext4 get_block
3871 * will just simply mark the buffer mapped but still
3872 * keep the extents uninitialized.
3874 * for non AIO case, we will convert those unwritten extents
3875 * to written after return back from blockdev_direct_IO.
3877 * for async DIO, the conversion needs to be defered when
3878 * the IO is completed. The ext4 end_io callback function
3879 * will be called to take care of the conversion work.
3880 * Here for async case, we allocate an io_end structure to
3883 iocb->private = NULL;
3884 EXT4_I(inode)->cur_aio_dio = NULL;
3885 if (!is_sync_kiocb(iocb)) {
3886 iocb->private = ext4_init_io_end(inode, GFP_NOFS);
3890 * we save the io structure for current async
3891 * direct IO, so that later ext4_get_blocks()
3892 * could flag the io structure whether there
3893 * is a unwritten extents needs to be converted
3894 * when IO is completed.
3896 EXT4_I(inode)->cur_aio_dio = iocb->private;
3899 ret = blockdev_direct_IO(rw, iocb, inode,
3900 inode->i_sb->s_bdev, iov,
3902 ext4_get_block_write,
3905 EXT4_I(inode)->cur_aio_dio = NULL;
3907 * The io_end structure takes a reference to the inode,
3908 * that structure needs to be destroyed and the
3909 * reference to the inode need to be dropped, when IO is
3910 * complete, even with 0 byte write, or failed.
3912 * In the successful AIO DIO case, the io_end structure will be
3913 * desctroyed and the reference to the inode will be dropped
3914 * after the end_io call back function is called.
3916 * In the case there is 0 byte write, or error case, since
3917 * VFS direct IO won't invoke the end_io call back function,
3918 * we need to free the end_io structure here.
3920 if (ret != -EIOCBQUEUED && ret <= 0 && iocb->private) {
3921 ext4_free_io_end(iocb->private);
3922 iocb->private = NULL;
3923 } else if (ret > 0 && ext4_test_inode_state(inode,
3924 EXT4_STATE_DIO_UNWRITTEN)) {
3927 * for non AIO case, since the IO is already
3928 * completed, we could do the convertion right here
3930 err = ext4_convert_unwritten_extents(inode,
3934 ext4_clear_inode_state(inode, EXT4_STATE_DIO_UNWRITTEN);
3939 /* for write the the end of file case, we fall back to old way */
3940 return ext4_ind_direct_IO(rw, iocb, iov, offset, nr_segs);
3943 static ssize_t ext4_direct_IO(int rw, struct kiocb *iocb,
3944 const struct iovec *iov, loff_t offset,
3945 unsigned long nr_segs)
3947 struct file *file = iocb->ki_filp;
3948 struct inode *inode = file->f_mapping->host;
3950 if (EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL)
3951 return ext4_ext_direct_IO(rw, iocb, iov, offset, nr_segs);
3953 return ext4_ind_direct_IO(rw, iocb, iov, offset, nr_segs);
3957 * Pages can be marked dirty completely asynchronously from ext4's journalling
3958 * activity. By filemap_sync_pte(), try_to_unmap_one(), etc. We cannot do
3959 * much here because ->set_page_dirty is called under VFS locks. The page is
3960 * not necessarily locked.
3962 * We cannot just dirty the page and leave attached buffers clean, because the
3963 * buffers' dirty state is "definitive". We cannot just set the buffers dirty
3964 * or jbddirty because all the journalling code will explode.
3966 * So what we do is to mark the page "pending dirty" and next time writepage
3967 * is called, propagate that into the buffers appropriately.
3969 static int ext4_journalled_set_page_dirty(struct page *page)
3971 SetPageChecked(page);
3972 return __set_page_dirty_nobuffers(page);
3975 static const struct address_space_operations ext4_ordered_aops = {
3976 .readpage = ext4_readpage,
3977 .readpages = ext4_readpages,
3978 .writepage = ext4_writepage,
3979 .sync_page = block_sync_page,
3980 .write_begin = ext4_write_begin,
3981 .write_end = ext4_ordered_write_end,
3983 .invalidatepage = ext4_invalidatepage,
3984 .releasepage = ext4_releasepage,
3985 .direct_IO = ext4_direct_IO,
3986 .migratepage = buffer_migrate_page,
3987 .is_partially_uptodate = block_is_partially_uptodate,
3988 .error_remove_page = generic_error_remove_page,
3991 static const struct address_space_operations ext4_writeback_aops = {
3992 .readpage = ext4_readpage,
3993 .readpages = ext4_readpages,
3994 .writepage = ext4_writepage,
3995 .sync_page = block_sync_page,
3996 .write_begin = ext4_write_begin,
3997 .write_end = ext4_writeback_write_end,
3999 .invalidatepage = ext4_invalidatepage,
4000 .releasepage = ext4_releasepage,
4001 .direct_IO = ext4_direct_IO,
4002 .migratepage = buffer_migrate_page,
4003 .is_partially_uptodate = block_is_partially_uptodate,
4004 .error_remove_page = generic_error_remove_page,
4007 static const struct address_space_operations ext4_journalled_aops = {
4008 .readpage = ext4_readpage,
4009 .readpages = ext4_readpages,
4010 .writepage = ext4_writepage,
4011 .sync_page = block_sync_page,
4012 .write_begin = ext4_write_begin,
4013 .write_end = ext4_journalled_write_end,
4014 .set_page_dirty = ext4_journalled_set_page_dirty,
4016 .invalidatepage = ext4_invalidatepage,
4017 .releasepage = ext4_releasepage,
4018 .is_partially_uptodate = block_is_partially_uptodate,
4019 .error_remove_page = generic_error_remove_page,
4022 static const struct address_space_operations ext4_da_aops = {
4023 .readpage = ext4_readpage,
4024 .readpages = ext4_readpages,
4025 .writepage = ext4_writepage,
4026 .writepages = ext4_da_writepages,
4027 .sync_page = block_sync_page,
4028 .write_begin = ext4_da_write_begin,
4029 .write_end = ext4_da_write_end,
4031 .invalidatepage = ext4_da_invalidatepage,
4032 .releasepage = ext4_releasepage,
4033 .direct_IO = ext4_direct_IO,
4034 .migratepage = buffer_migrate_page,
4035 .is_partially_uptodate = block_is_partially_uptodate,
4036 .error_remove_page = generic_error_remove_page,
4039 void ext4_set_aops(struct inode *inode)
4041 if (ext4_should_order_data(inode) &&
4042 test_opt(inode->i_sb, DELALLOC))
4043 inode->i_mapping->a_ops = &ext4_da_aops;
4044 else if (ext4_should_order_data(inode))
4045 inode->i_mapping->a_ops = &ext4_ordered_aops;
4046 else if (ext4_should_writeback_data(inode) &&
4047 test_opt(inode->i_sb, DELALLOC))
4048 inode->i_mapping->a_ops = &ext4_da_aops;
4049 else if (ext4_should_writeback_data(inode))
4050 inode->i_mapping->a_ops = &ext4_writeback_aops;
4052 inode->i_mapping->a_ops = &ext4_journalled_aops;
4056 * ext4_block_truncate_page() zeroes out a mapping from file offset `from'
4057 * up to the end of the block which corresponds to `from'.
4058 * This required during truncate. We need to physically zero the tail end
4059 * of that block so it doesn't yield old data if the file is later grown.
4061 int ext4_block_truncate_page(handle_t *handle,
4062 struct address_space *mapping, loff_t from)
4064 ext4_fsblk_t index = from >> PAGE_CACHE_SHIFT;
4065 unsigned offset = from & (PAGE_CACHE_SIZE-1);
4066 unsigned blocksize, length, pos;
4068 struct inode *inode = mapping->host;
4069 struct buffer_head *bh;
4073 page = find_or_create_page(mapping, from >> PAGE_CACHE_SHIFT,
4074 mapping_gfp_mask(mapping) & ~__GFP_FS);
4078 blocksize = inode->i_sb->s_blocksize;
4079 length = blocksize - (offset & (blocksize - 1));
4080 iblock = index << (PAGE_CACHE_SHIFT - inode->i_sb->s_blocksize_bits);
4083 * For "nobh" option, we can only work if we don't need to
4084 * read-in the page - otherwise we create buffers to do the IO.
4086 if (!page_has_buffers(page) && test_opt(inode->i_sb, NOBH) &&
4087 ext4_should_writeback_data(inode) && PageUptodate(page)) {
4088 zero_user(page, offset, length);
4089 set_page_dirty(page);
4093 if (!page_has_buffers(page))
4094 create_empty_buffers(page, blocksize, 0);
4096 /* Find the buffer that contains "offset" */
4097 bh = page_buffers(page);
4099 while (offset >= pos) {
4100 bh = bh->b_this_page;
4106 if (buffer_freed(bh)) {
4107 BUFFER_TRACE(bh, "freed: skip");
4111 if (!buffer_mapped(bh)) {
4112 BUFFER_TRACE(bh, "unmapped");
4113 ext4_get_block(inode, iblock, bh, 0);
4114 /* unmapped? It's a hole - nothing to do */
4115 if (!buffer_mapped(bh)) {
4116 BUFFER_TRACE(bh, "still unmapped");
4121 /* Ok, it's mapped. Make sure it's up-to-date */
4122 if (PageUptodate(page))
4123 set_buffer_uptodate(bh);
4125 if (!buffer_uptodate(bh)) {
4127 ll_rw_block(READ, 1, &bh);
4129 /* Uhhuh. Read error. Complain and punt. */
4130 if (!buffer_uptodate(bh))
4134 if (ext4_should_journal_data(inode)) {
4135 BUFFER_TRACE(bh, "get write access");
4136 err = ext4_journal_get_write_access(handle, bh);
4141 zero_user(page, offset, length);
4143 BUFFER_TRACE(bh, "zeroed end of block");
4146 if (ext4_should_journal_data(inode)) {
4147 err = ext4_handle_dirty_metadata(handle, inode, bh);
4149 if (ext4_should_order_data(inode))
4150 err = ext4_jbd2_file_inode(handle, inode);
4151 mark_buffer_dirty(bh);
4156 page_cache_release(page);
4161 * Probably it should be a library function... search for first non-zero word
4162 * or memcmp with zero_page, whatever is better for particular architecture.
4165 static inline int all_zeroes(__le32 *p, __le32 *q)
4174 * ext4_find_shared - find the indirect blocks for partial truncation.
4175 * @inode: inode in question
4176 * @depth: depth of the affected branch
4177 * @offsets: offsets of pointers in that branch (see ext4_block_to_path)
4178 * @chain: place to store the pointers to partial indirect blocks
4179 * @top: place to the (detached) top of branch
4181 * This is a helper function used by ext4_truncate().
4183 * When we do truncate() we may have to clean the ends of several
4184 * indirect blocks but leave the blocks themselves alive. Block is
4185 * partially truncated if some data below the new i_size is refered
4186 * from it (and it is on the path to the first completely truncated
4187 * data block, indeed). We have to free the top of that path along
4188 * with everything to the right of the path. Since no allocation
4189 * past the truncation point is possible until ext4_truncate()
4190 * finishes, we may safely do the latter, but top of branch may
4191 * require special attention - pageout below the truncation point
4192 * might try to populate it.
4194 * We atomically detach the top of branch from the tree, store the
4195 * block number of its root in *@top, pointers to buffer_heads of
4196 * partially truncated blocks - in @chain[].bh and pointers to
4197 * their last elements that should not be removed - in
4198 * @chain[].p. Return value is the pointer to last filled element
4201 * The work left to caller to do the actual freeing of subtrees:
4202 * a) free the subtree starting from *@top
4203 * b) free the subtrees whose roots are stored in
4204 * (@chain[i].p+1 .. end of @chain[i].bh->b_data)
4205 * c) free the subtrees growing from the inode past the @chain[0].
4206 * (no partially truncated stuff there). */
4208 static Indirect *ext4_find_shared(struct inode *inode, int depth,
4209 ext4_lblk_t offsets[4], Indirect chain[4],
4212 Indirect *partial, *p;
4216 /* Make k index the deepest non-null offset + 1 */
4217 for (k = depth; k > 1 && !offsets[k-1]; k--)
4219 partial = ext4_get_branch(inode, k, offsets, chain, &err);
4220 /* Writer: pointers */
4222 partial = chain + k-1;
4224 * If the branch acquired continuation since we've looked at it -
4225 * fine, it should all survive and (new) top doesn't belong to us.
4227 if (!partial->key && *partial->p)
4230 for (p = partial; (p > chain) && all_zeroes((__le32 *) p->bh->b_data, p->p); p--)
4233 * OK, we've found the last block that must survive. The rest of our
4234 * branch should be detached before unlocking. However, if that rest
4235 * of branch is all ours and does not grow immediately from the inode
4236 * it's easier to cheat and just decrement partial->p.
4238 if (p == chain + k - 1 && p > chain) {
4242 /* Nope, don't do this in ext4. Must leave the tree intact */
4249 while (partial > p) {
4250 brelse(partial->bh);
4258 * Zero a number of block pointers in either an inode or an indirect block.
4259 * If we restart the transaction we must again get write access to the
4260 * indirect block for further modification.
4262 * We release `count' blocks on disk, but (last - first) may be greater
4263 * than `count' because there can be holes in there.
4265 static int ext4_clear_blocks(handle_t *handle, struct inode *inode,
4266 struct buffer_head *bh,
4267 ext4_fsblk_t block_to_free,
4268 unsigned long count, __le32 *first,
4272 int flags = EXT4_FREE_BLOCKS_FORGET | EXT4_FREE_BLOCKS_VALIDATED;
4274 if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode))
4275 flags |= EXT4_FREE_BLOCKS_METADATA;
4277 if (!ext4_data_block_valid(EXT4_SB(inode->i_sb), block_to_free,
4279 ext4_error(inode->i_sb, "inode #%lu: "
4280 "attempt to clear blocks %llu len %lu, invalid",
4281 inode->i_ino, (unsigned long long) block_to_free,
4286 if (try_to_extend_transaction(handle, inode)) {
4288 BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
4289 ext4_handle_dirty_metadata(handle, inode, bh);
4291 ext4_mark_inode_dirty(handle, inode);
4292 ext4_truncate_restart_trans(handle, inode,
4293 blocks_for_truncate(inode));
4295 BUFFER_TRACE(bh, "retaking write access");
4296 ext4_journal_get_write_access(handle, bh);
4300 for (p = first; p < last; p++)
4303 ext4_free_blocks(handle, inode, 0, block_to_free, count, flags);
4308 * ext4_free_data - free a list of data blocks
4309 * @handle: handle for this transaction
4310 * @inode: inode we are dealing with
4311 * @this_bh: indirect buffer_head which contains *@first and *@last
4312 * @first: array of block numbers
4313 * @last: points immediately past the end of array
4315 * We are freeing all blocks refered from that array (numbers are stored as
4316 * little-endian 32-bit) and updating @inode->i_blocks appropriately.
4318 * We accumulate contiguous runs of blocks to free. Conveniently, if these
4319 * blocks are contiguous then releasing them at one time will only affect one
4320 * or two bitmap blocks (+ group descriptor(s) and superblock) and we won't
4321 * actually use a lot of journal space.
4323 * @this_bh will be %NULL if @first and @last point into the inode's direct
4326 static void ext4_free_data(handle_t *handle, struct inode *inode,
4327 struct buffer_head *this_bh,
4328 __le32 *first, __le32 *last)
4330 ext4_fsblk_t block_to_free = 0; /* Starting block # of a run */
4331 unsigned long count = 0; /* Number of blocks in the run */
4332 __le32 *block_to_free_p = NULL; /* Pointer into inode/ind
4335 ext4_fsblk_t nr; /* Current block # */
4336 __le32 *p; /* Pointer into inode/ind
4337 for current block */
4340 if (this_bh) { /* For indirect block */
4341 BUFFER_TRACE(this_bh, "get_write_access");
4342 err = ext4_journal_get_write_access(handle, this_bh);
4343 /* Important: if we can't update the indirect pointers
4344 * to the blocks, we can't free them. */
4349 for (p = first; p < last; p++) {
4350 nr = le32_to_cpu(*p);
4352 /* accumulate blocks to free if they're contiguous */
4355 block_to_free_p = p;
4357 } else if (nr == block_to_free + count) {
4360 if (ext4_clear_blocks(handle, inode, this_bh,
4361 block_to_free, count,
4362 block_to_free_p, p))
4365 block_to_free_p = p;
4372 ext4_clear_blocks(handle, inode, this_bh, block_to_free,
4373 count, block_to_free_p, p);
4376 BUFFER_TRACE(this_bh, "call ext4_handle_dirty_metadata");
4379 * The buffer head should have an attached journal head at this
4380 * point. However, if the data is corrupted and an indirect
4381 * block pointed to itself, it would have been detached when
4382 * the block was cleared. Check for this instead of OOPSing.
4384 if ((EXT4_JOURNAL(inode) == NULL) || bh2jh(this_bh))
4385 ext4_handle_dirty_metadata(handle, inode, this_bh);
4387 ext4_error(inode->i_sb,
4388 "circular indirect block detected, "
4389 "inode=%lu, block=%llu",
4391 (unsigned long long) this_bh->b_blocknr);
4396 * ext4_free_branches - free an array of branches
4397 * @handle: JBD handle for this transaction
4398 * @inode: inode we are dealing with
4399 * @parent_bh: the buffer_head which contains *@first and *@last
4400 * @first: array of block numbers
4401 * @last: pointer immediately past the end of array
4402 * @depth: depth of the branches to free
4404 * We are freeing all blocks refered from these branches (numbers are
4405 * stored as little-endian 32-bit) and updating @inode->i_blocks
4408 static void ext4_free_branches(handle_t *handle, struct inode *inode,
4409 struct buffer_head *parent_bh,
4410 __le32 *first, __le32 *last, int depth)
4415 if (ext4_handle_is_aborted(handle))
4419 struct buffer_head *bh;
4420 int addr_per_block = EXT4_ADDR_PER_BLOCK(inode->i_sb);
4422 while (--p >= first) {
4423 nr = le32_to_cpu(*p);
4425 continue; /* A hole */
4427 if (!ext4_data_block_valid(EXT4_SB(inode->i_sb),
4429 ext4_error(inode->i_sb,
4430 "indirect mapped block in inode "
4431 "#%lu invalid (level %d, blk #%lu)",
4432 inode->i_ino, depth,
4433 (unsigned long) nr);
4437 /* Go read the buffer for the next level down */
4438 bh = sb_bread(inode->i_sb, nr);
4441 * A read failure? Report error and clear slot
4445 ext4_error(inode->i_sb,
4446 "Read failure, inode=%lu, block=%llu",
4451 /* This zaps the entire block. Bottom up. */
4452 BUFFER_TRACE(bh, "free child branches");
4453 ext4_free_branches(handle, inode, bh,
4454 (__le32 *) bh->b_data,
4455 (__le32 *) bh->b_data + addr_per_block,
4459 * We've probably journalled the indirect block several
4460 * times during the truncate. But it's no longer
4461 * needed and we now drop it from the transaction via
4462 * jbd2_journal_revoke().
4464 * That's easy if it's exclusively part of this
4465 * transaction. But if it's part of the committing
4466 * transaction then jbd2_journal_forget() will simply
4467 * brelse() it. That means that if the underlying
4468 * block is reallocated in ext4_get_block(),
4469 * unmap_underlying_metadata() will find this block
4470 * and will try to get rid of it. damn, damn.
4472 * If this block has already been committed to the
4473 * journal, a revoke record will be written. And
4474 * revoke records must be emitted *before* clearing
4475 * this block's bit in the bitmaps.
4477 ext4_forget(handle, 1, inode, bh, bh->b_blocknr);
4480 * Everything below this this pointer has been
4481 * released. Now let this top-of-subtree go.
4483 * We want the freeing of this indirect block to be
4484 * atomic in the journal with the updating of the
4485 * bitmap block which owns it. So make some room in
4488 * We zero the parent pointer *after* freeing its
4489 * pointee in the bitmaps, so if extend_transaction()
4490 * for some reason fails to put the bitmap changes and
4491 * the release into the same transaction, recovery
4492 * will merely complain about releasing a free block,
4493 * rather than leaking blocks.
4495 if (ext4_handle_is_aborted(handle))
4497 if (try_to_extend_transaction(handle, inode)) {
4498 ext4_mark_inode_dirty(handle, inode);
4499 ext4_truncate_restart_trans(handle, inode,
4500 blocks_for_truncate(inode));
4503 ext4_free_blocks(handle, inode, 0, nr, 1,
4504 EXT4_FREE_BLOCKS_METADATA);
4508 * The block which we have just freed is
4509 * pointed to by an indirect block: journal it
4511 BUFFER_TRACE(parent_bh, "get_write_access");
4512 if (!ext4_journal_get_write_access(handle,
4515 BUFFER_TRACE(parent_bh,
4516 "call ext4_handle_dirty_metadata");
4517 ext4_handle_dirty_metadata(handle,
4524 /* We have reached the bottom of the tree. */
4525 BUFFER_TRACE(parent_bh, "free data blocks");
4526 ext4_free_data(handle, inode, parent_bh, first, last);
4530 int ext4_can_truncate(struct inode *inode)
4532 if (IS_APPEND(inode) || IS_IMMUTABLE(inode))
4534 if (S_ISREG(inode->i_mode))
4536 if (S_ISDIR(inode->i_mode))
4538 if (S_ISLNK(inode->i_mode))
4539 return !ext4_inode_is_fast_symlink(inode);
4546 * We block out ext4_get_block() block instantiations across the entire
4547 * transaction, and VFS/VM ensures that ext4_truncate() cannot run
4548 * simultaneously on behalf of the same inode.
4550 * As we work through the truncate and commmit bits of it to the journal there
4551 * is one core, guiding principle: the file's tree must always be consistent on
4552 * disk. We must be able to restart the truncate after a crash.
4554 * The file's tree may be transiently inconsistent in memory (although it
4555 * probably isn't), but whenever we close off and commit a journal transaction,
4556 * the contents of (the filesystem + the journal) must be consistent and
4557 * restartable. It's pretty simple, really: bottom up, right to left (although
4558 * left-to-right works OK too).
4560 * Note that at recovery time, journal replay occurs *before* the restart of
4561 * truncate against the orphan inode list.
4563 * The committed inode has the new, desired i_size (which is the same as
4564 * i_disksize in this case). After a crash, ext4_orphan_cleanup() will see
4565 * that this inode's truncate did not complete and it will again call
4566 * ext4_truncate() to have another go. So there will be instantiated blocks
4567 * to the right of the truncation point in a crashed ext4 filesystem. But
4568 * that's fine - as long as they are linked from the inode, the post-crash
4569 * ext4_truncate() run will find them and release them.
4571 void ext4_truncate(struct inode *inode)
4574 struct ext4_inode_info *ei = EXT4_I(inode);
4575 __le32 *i_data = ei->i_data;
4576 int addr_per_block = EXT4_ADDR_PER_BLOCK(inode->i_sb);
4577 struct address_space *mapping = inode->i_mapping;
4578 ext4_lblk_t offsets[4];
4583 ext4_lblk_t last_block;
4584 unsigned blocksize = inode->i_sb->s_blocksize;
4586 if (!ext4_can_truncate(inode))
4589 EXT4_I(inode)->i_flags &= ~EXT4_EOFBLOCKS_FL;
4591 if (inode->i_size == 0 && !test_opt(inode->i_sb, NO_AUTO_DA_ALLOC))
4592 ext4_set_inode_state(inode, EXT4_STATE_DA_ALLOC_CLOSE);
4594 if (EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL) {
4595 ext4_ext_truncate(inode);
4599 handle = start_transaction(inode);
4601 return; /* AKPM: return what? */
4603 last_block = (inode->i_size + blocksize-1)
4604 >> EXT4_BLOCK_SIZE_BITS(inode->i_sb);
4606 if (inode->i_size & (blocksize - 1))
4607 if (ext4_block_truncate_page(handle, mapping, inode->i_size))
4610 n = ext4_block_to_path(inode, last_block, offsets, NULL);
4612 goto out_stop; /* error */
4615 * OK. This truncate is going to happen. We add the inode to the
4616 * orphan list, so that if this truncate spans multiple transactions,
4617 * and we crash, we will resume the truncate when the filesystem
4618 * recovers. It also marks the inode dirty, to catch the new size.
4620 * Implication: the file must always be in a sane, consistent
4621 * truncatable state while each transaction commits.
4623 if (ext4_orphan_add(handle, inode))
4627 * From here we block out all ext4_get_block() callers who want to
4628 * modify the block allocation tree.
4630 down_write(&ei->i_data_sem);
4632 ext4_discard_preallocations(inode);
4635 * The orphan list entry will now protect us from any crash which
4636 * occurs before the truncate completes, so it is now safe to propagate
4637 * the new, shorter inode size (held for now in i_size) into the
4638 * on-disk inode. We do this via i_disksize, which is the value which
4639 * ext4 *really* writes onto the disk inode.
4641 ei->i_disksize = inode->i_size;
4643 if (n == 1) { /* direct blocks */
4644 ext4_free_data(handle, inode, NULL, i_data+offsets[0],
4645 i_data + EXT4_NDIR_BLOCKS);
4649 partial = ext4_find_shared(inode, n, offsets, chain, &nr);
4650 /* Kill the top of shared branch (not detached) */
4652 if (partial == chain) {
4653 /* Shared branch grows from the inode */
4654 ext4_free_branches(handle, inode, NULL,
4655 &nr, &nr+1, (chain+n-1) - partial);
4658 * We mark the inode dirty prior to restart,
4659 * and prior to stop. No need for it here.
4662 /* Shared branch grows from an indirect block */
4663 BUFFER_TRACE(partial->bh, "get_write_access");
4664 ext4_free_branches(handle, inode, partial->bh,
4666 partial->p+1, (chain+n-1) - partial);
4669 /* Clear the ends of indirect blocks on the shared branch */
4670 while (partial > chain) {
4671 ext4_free_branches(handle, inode, partial->bh, partial->p + 1,
4672 (__le32*)partial->bh->b_data+addr_per_block,
4673 (chain+n-1) - partial);
4674 BUFFER_TRACE(partial->bh, "call brelse");
4675 brelse(partial->bh);
4679 /* Kill the remaining (whole) subtrees */
4680 switch (offsets[0]) {
4682 nr = i_data[EXT4_IND_BLOCK];
4684 ext4_free_branches(handle, inode, NULL, &nr, &nr+1, 1);
4685 i_data[EXT4_IND_BLOCK] = 0;
4687 case EXT4_IND_BLOCK:
4688 nr = i_data[EXT4_DIND_BLOCK];
4690 ext4_free_branches(handle, inode, NULL, &nr, &nr+1, 2);
4691 i_data[EXT4_DIND_BLOCK] = 0;
4693 case EXT4_DIND_BLOCK:
4694 nr = i_data[EXT4_TIND_BLOCK];
4696 ext4_free_branches(handle, inode, NULL, &nr, &nr+1, 3);
4697 i_data[EXT4_TIND_BLOCK] = 0;
4699 case EXT4_TIND_BLOCK:
4703 up_write(&ei->i_data_sem);
4704 inode->i_mtime = inode->i_ctime = ext4_current_time(inode);
4705 ext4_mark_inode_dirty(handle, inode);
4708 * In a multi-transaction truncate, we only make the final transaction
4712 ext4_handle_sync(handle);
4715 * If this was a simple ftruncate(), and the file will remain alive
4716 * then we need to clear up the orphan record which we created above.
4717 * However, if this was a real unlink then we were called by
4718 * ext4_delete_inode(), and we allow that function to clean up the
4719 * orphan info for us.
4722 ext4_orphan_del(handle, inode);
4724 ext4_journal_stop(handle);
4728 * ext4_get_inode_loc returns with an extra refcount against the inode's
4729 * underlying buffer_head on success. If 'in_mem' is true, we have all
4730 * data in memory that is needed to recreate the on-disk version of this
4733 static int __ext4_get_inode_loc(struct inode *inode,
4734 struct ext4_iloc *iloc, int in_mem)
4736 struct ext4_group_desc *gdp;
4737 struct buffer_head *bh;
4738 struct super_block *sb = inode->i_sb;
4740 int inodes_per_block, inode_offset;
4743 if (!ext4_valid_inum(sb, inode->i_ino))
4746 iloc->block_group = (inode->i_ino - 1) / EXT4_INODES_PER_GROUP(sb);
4747 gdp = ext4_get_group_desc(sb, iloc->block_group, NULL);
4752 * Figure out the offset within the block group inode table
4754 inodes_per_block = (EXT4_BLOCK_SIZE(sb) / EXT4_INODE_SIZE(sb));
4755 inode_offset = ((inode->i_ino - 1) %
4756 EXT4_INODES_PER_GROUP(sb));
4757 block = ext4_inode_table(sb, gdp) + (inode_offset / inodes_per_block);
4758 iloc->offset = (inode_offset % inodes_per_block) * EXT4_INODE_SIZE(sb);
4760 bh = sb_getblk(sb, block);
4762 ext4_error(sb, "unable to read inode block - "
4763 "inode=%lu, block=%llu", inode->i_ino, block);
4766 if (!buffer_uptodate(bh)) {
4770 * If the buffer has the write error flag, we have failed
4771 * to write out another inode in the same block. In this
4772 * case, we don't have to read the block because we may
4773 * read the old inode data successfully.
4775 if (buffer_write_io_error(bh) && !buffer_uptodate(bh))
4776 set_buffer_uptodate(bh);
4778 if (buffer_uptodate(bh)) {
4779 /* someone brought it uptodate while we waited */
4785 * If we have all information of the inode in memory and this
4786 * is the only valid inode in the block, we need not read the
4790 struct buffer_head *bitmap_bh;
4793 start = inode_offset & ~(inodes_per_block - 1);
4795 /* Is the inode bitmap in cache? */
4796 bitmap_bh = sb_getblk(sb, ext4_inode_bitmap(sb, gdp));
4801 * If the inode bitmap isn't in cache then the
4802 * optimisation may end up performing two reads instead
4803 * of one, so skip it.
4805 if (!buffer_uptodate(bitmap_bh)) {
4809 for (i = start; i < start + inodes_per_block; i++) {
4810 if (i == inode_offset)
4812 if (ext4_test_bit(i, bitmap_bh->b_data))
4816 if (i == start + inodes_per_block) {
4817 /* all other inodes are free, so skip I/O */
4818 memset(bh->b_data, 0, bh->b_size);
4819 set_buffer_uptodate(bh);
4827 * If we need to do any I/O, try to pre-readahead extra
4828 * blocks from the inode table.
4830 if (EXT4_SB(sb)->s_inode_readahead_blks) {
4831 ext4_fsblk_t b, end, table;
4834 table = ext4_inode_table(sb, gdp);
4835 /* s_inode_readahead_blks is always a power of 2 */
4836 b = block & ~(EXT4_SB(sb)->s_inode_readahead_blks-1);
4839 end = b + EXT4_SB(sb)->s_inode_readahead_blks;
4840 num = EXT4_INODES_PER_GROUP(sb);
4841 if (EXT4_HAS_RO_COMPAT_FEATURE(sb,
4842 EXT4_FEATURE_RO_COMPAT_GDT_CSUM))
4843 num -= ext4_itable_unused_count(sb, gdp);
4844 table += num / inodes_per_block;
4848 sb_breadahead(sb, b++);
4852 * There are other valid inodes in the buffer, this inode
4853 * has in-inode xattrs, or we don't have this inode in memory.
4854 * Read the block from disk.
4857 bh->b_end_io = end_buffer_read_sync;
4858 submit_bh(READ_META, bh);
4860 if (!buffer_uptodate(bh)) {
4861 ext4_error(sb, "unable to read inode block - inode=%lu,"
4862 " block=%llu", inode->i_ino, block);
4872 int ext4_get_inode_loc(struct inode *inode, struct ext4_iloc *iloc)
4874 /* We have all inode data except xattrs in memory here. */
4875 return __ext4_get_inode_loc(inode, iloc,
4876 !ext4_test_inode_state(inode, EXT4_STATE_XATTR));
4879 void ext4_set_inode_flags(struct inode *inode)
4881 unsigned int flags = EXT4_I(inode)->i_flags;
4883 inode->i_flags &= ~(S_SYNC|S_APPEND|S_IMMUTABLE|S_NOATIME|S_DIRSYNC);
4884 if (flags & EXT4_SYNC_FL)
4885 inode->i_flags |= S_SYNC;
4886 if (flags & EXT4_APPEND_FL)
4887 inode->i_flags |= S_APPEND;
4888 if (flags & EXT4_IMMUTABLE_FL)
4889 inode->i_flags |= S_IMMUTABLE;
4890 if (flags & EXT4_NOATIME_FL)
4891 inode->i_flags |= S_NOATIME;
4892 if (flags & EXT4_DIRSYNC_FL)
4893 inode->i_flags |= S_DIRSYNC;
4896 /* Propagate flags from i_flags to EXT4_I(inode)->i_flags */
4897 void ext4_get_inode_flags(struct ext4_inode_info *ei)
4899 unsigned int flags = ei->vfs_inode.i_flags;
4901 ei->i_flags &= ~(EXT4_SYNC_FL|EXT4_APPEND_FL|
4902 EXT4_IMMUTABLE_FL|EXT4_NOATIME_FL|EXT4_DIRSYNC_FL);
4904 ei->i_flags |= EXT4_SYNC_FL;
4905 if (flags & S_APPEND)
4906 ei->i_flags |= EXT4_APPEND_FL;
4907 if (flags & S_IMMUTABLE)
4908 ei->i_flags |= EXT4_IMMUTABLE_FL;
4909 if (flags & S_NOATIME)
4910 ei->i_flags |= EXT4_NOATIME_FL;
4911 if (flags & S_DIRSYNC)
4912 ei->i_flags |= EXT4_DIRSYNC_FL;
4915 static blkcnt_t ext4_inode_blocks(struct ext4_inode *raw_inode,
4916 struct ext4_inode_info *ei)
4919 struct inode *inode = &(ei->vfs_inode);
4920 struct super_block *sb = inode->i_sb;
4922 if (EXT4_HAS_RO_COMPAT_FEATURE(sb,
4923 EXT4_FEATURE_RO_COMPAT_HUGE_FILE)) {
4924 /* we are using combined 48 bit field */
4925 i_blocks = ((u64)le16_to_cpu(raw_inode->i_blocks_high)) << 32 |
4926 le32_to_cpu(raw_inode->i_blocks_lo);
4927 if (ei->i_flags & EXT4_HUGE_FILE_FL) {
4928 /* i_blocks represent file system block size */
4929 return i_blocks << (inode->i_blkbits - 9);
4934 return le32_to_cpu(raw_inode->i_blocks_lo);
4938 struct inode *ext4_iget(struct super_block *sb, unsigned long ino)
4940 struct ext4_iloc iloc;
4941 struct ext4_inode *raw_inode;
4942 struct ext4_inode_info *ei;
4943 struct inode *inode;
4944 journal_t *journal = EXT4_SB(sb)->s_journal;
4948 inode = iget_locked(sb, ino);
4950 return ERR_PTR(-ENOMEM);
4951 if (!(inode->i_state & I_NEW))
4957 ret = __ext4_get_inode_loc(inode, &iloc, 0);
4960 raw_inode = ext4_raw_inode(&iloc);
4961 inode->i_mode = le16_to_cpu(raw_inode->i_mode);
4962 inode->i_uid = (uid_t)le16_to_cpu(raw_inode->i_uid_low);
4963 inode->i_gid = (gid_t)le16_to_cpu(raw_inode->i_gid_low);
4964 if (!(test_opt(inode->i_sb, NO_UID32))) {
4965 inode->i_uid |= le16_to_cpu(raw_inode->i_uid_high) << 16;
4966 inode->i_gid |= le16_to_cpu(raw_inode->i_gid_high) << 16;
4968 inode->i_nlink = le16_to_cpu(raw_inode->i_links_count);
4970 ei->i_state_flags = 0;
4971 ei->i_dir_start_lookup = 0;
4972 ei->i_dtime = le32_to_cpu(raw_inode->i_dtime);
4973 /* We now have enough fields to check if the inode was active or not.
4974 * This is needed because nfsd might try to access dead inodes
4975 * the test is that same one that e2fsck uses
4976 * NeilBrown 1999oct15
4978 if (inode->i_nlink == 0) {
4979 if (inode->i_mode == 0 ||
4980 !(EXT4_SB(inode->i_sb)->s_mount_state & EXT4_ORPHAN_FS)) {
4981 /* this inode is deleted */
4985 /* The only unlinked inodes we let through here have
4986 * valid i_mode and are being read by the orphan
4987 * recovery code: that's fine, we're about to complete
4988 * the process of deleting those. */
4990 ei->i_flags = le32_to_cpu(raw_inode->i_flags);
4991 inode->i_blocks = ext4_inode_blocks(raw_inode, ei);
4992 ei->i_file_acl = le32_to_cpu(raw_inode->i_file_acl_lo);
4993 if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_64BIT))
4995 ((__u64)le16_to_cpu(raw_inode->i_file_acl_high)) << 32;
4996 inode->i_size = ext4_isize(raw_inode);
4997 ei->i_disksize = inode->i_size;
4999 ei->i_reserved_quota = 0;
5001 inode->i_generation = le32_to_cpu(raw_inode->i_generation);
5002 ei->i_block_group = iloc.block_group;
5003 ei->i_last_alloc_group = ~0;
5005 * NOTE! The in-memory inode i_data array is in little-endian order
5006 * even on big-endian machines: we do NOT byteswap the block numbers!
5008 for (block = 0; block < EXT4_N_BLOCKS; block++)
5009 ei->i_data[block] = raw_inode->i_block[block];
5010 INIT_LIST_HEAD(&ei->i_orphan);
5013 * Set transaction id's of transactions that have to be committed
5014 * to finish f[data]sync. We set them to currently running transaction
5015 * as we cannot be sure that the inode or some of its metadata isn't
5016 * part of the transaction - the inode could have been reclaimed and
5017 * now it is reread from disk.
5020 transaction_t *transaction;
5023 spin_lock(&journal->j_state_lock);
5024 if (journal->j_running_transaction)
5025 transaction = journal->j_running_transaction;
5027 transaction = journal->j_committing_transaction;
5029 tid = transaction->t_tid;
5031 tid = journal->j_commit_sequence;
5032 spin_unlock(&journal->j_state_lock);
5033 ei->i_sync_tid = tid;
5034 ei->i_datasync_tid = tid;
5037 if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE) {
5038 ei->i_extra_isize = le16_to_cpu(raw_inode->i_extra_isize);
5039 if (EXT4_GOOD_OLD_INODE_SIZE + ei->i_extra_isize >
5040 EXT4_INODE_SIZE(inode->i_sb)) {
5044 if (ei->i_extra_isize == 0) {
5045 /* The extra space is currently unused. Use it. */
5046 ei->i_extra_isize = sizeof(struct ext4_inode) -
5047 EXT4_GOOD_OLD_INODE_SIZE;
5049 __le32 *magic = (void *)raw_inode +
5050 EXT4_GOOD_OLD_INODE_SIZE +
5052 if (*magic == cpu_to_le32(EXT4_XATTR_MAGIC))
5053 ext4_set_inode_state(inode, EXT4_STATE_XATTR);
5056 ei->i_extra_isize = 0;
5058 EXT4_INODE_GET_XTIME(i_ctime, inode, raw_inode);
5059 EXT4_INODE_GET_XTIME(i_mtime, inode, raw_inode);
5060 EXT4_INODE_GET_XTIME(i_atime, inode, raw_inode);
5061 EXT4_EINODE_GET_XTIME(i_crtime, ei, raw_inode);
5063 inode->i_version = le32_to_cpu(raw_inode->i_disk_version);
5064 if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE) {
5065 if (EXT4_FITS_IN_INODE(raw_inode, ei, i_version_hi))
5067 (__u64)(le32_to_cpu(raw_inode->i_version_hi)) << 32;
5071 if (ei->i_file_acl &&
5072 !ext4_data_block_valid(EXT4_SB(sb), ei->i_file_acl, 1)) {
5073 ext4_error(sb, "bad extended attribute block %llu inode #%lu",
5074 ei->i_file_acl, inode->i_ino);
5077 } else if (ei->i_flags & EXT4_EXTENTS_FL) {
5078 if (S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
5079 (S_ISLNK(inode->i_mode) &&
5080 !ext4_inode_is_fast_symlink(inode)))
5081 /* Validate extent which is part of inode */
5082 ret = ext4_ext_check_inode(inode);
5083 } else if (S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
5084 (S_ISLNK(inode->i_mode) &&
5085 !ext4_inode_is_fast_symlink(inode))) {
5086 /* Validate block references which are part of inode */
5087 ret = ext4_check_inode_blockref(inode);
5092 if (S_ISREG(inode->i_mode)) {
5093 inode->i_op = &ext4_file_inode_operations;
5094 inode->i_fop = &ext4_file_operations;
5095 ext4_set_aops(inode);
5096 } else if (S_ISDIR(inode->i_mode)) {
5097 inode->i_op = &ext4_dir_inode_operations;
5098 inode->i_fop = &ext4_dir_operations;
5099 } else if (S_ISLNK(inode->i_mode)) {
5100 if (ext4_inode_is_fast_symlink(inode)) {
5101 inode->i_op = &ext4_fast_symlink_inode_operations;
5102 nd_terminate_link(ei->i_data, inode->i_size,
5103 sizeof(ei->i_data) - 1);
5105 inode->i_op = &ext4_symlink_inode_operations;
5106 ext4_set_aops(inode);
5108 } else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode) ||
5109 S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode)) {
5110 inode->i_op = &ext4_special_inode_operations;
5111 if (raw_inode->i_block[0])
5112 init_special_inode(inode, inode->i_mode,
5113 old_decode_dev(le32_to_cpu(raw_inode->i_block[0])));
5115 init_special_inode(inode, inode->i_mode,
5116 new_decode_dev(le32_to_cpu(raw_inode->i_block[1])));
5119 ext4_error(inode->i_sb, "bogus i_mode (%o) for inode=%lu",
5120 inode->i_mode, inode->i_ino);
5124 ext4_set_inode_flags(inode);
5125 unlock_new_inode(inode);
5131 return ERR_PTR(ret);
5134 static int ext4_inode_blocks_set(handle_t *handle,
5135 struct ext4_inode *raw_inode,
5136 struct ext4_inode_info *ei)
5138 struct inode *inode = &(ei->vfs_inode);
5139 u64 i_blocks = inode->i_blocks;
5140 struct super_block *sb = inode->i_sb;
5142 if (i_blocks <= ~0U) {
5144 * i_blocks can be represnted in a 32 bit variable
5145 * as multiple of 512 bytes
5147 raw_inode->i_blocks_lo = cpu_to_le32(i_blocks);
5148 raw_inode->i_blocks_high = 0;
5149 ei->i_flags &= ~EXT4_HUGE_FILE_FL;
5152 if (!EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_HUGE_FILE))
5155 if (i_blocks <= 0xffffffffffffULL) {
5157 * i_blocks can be represented in a 48 bit variable
5158 * as multiple of 512 bytes
5160 raw_inode->i_blocks_lo = cpu_to_le32(i_blocks);
5161 raw_inode->i_blocks_high = cpu_to_le16(i_blocks >> 32);
5162 ei->i_flags &= ~EXT4_HUGE_FILE_FL;
5164 ei->i_flags |= EXT4_HUGE_FILE_FL;
5165 /* i_block is stored in file system block size */
5166 i_blocks = i_blocks >> (inode->i_blkbits - 9);
5167 raw_inode->i_blocks_lo = cpu_to_le32(i_blocks);
5168 raw_inode->i_blocks_high = cpu_to_le16(i_blocks >> 32);
5174 * Post the struct inode info into an on-disk inode location in the
5175 * buffer-cache. This gobbles the caller's reference to the
5176 * buffer_head in the inode location struct.
5178 * The caller must have write access to iloc->bh.
5180 static int ext4_do_update_inode(handle_t *handle,
5181 struct inode *inode,
5182 struct ext4_iloc *iloc)
5184 struct ext4_inode *raw_inode = ext4_raw_inode(iloc);
5185 struct ext4_inode_info *ei = EXT4_I(inode);
5186 struct buffer_head *bh = iloc->bh;
5187 int err = 0, rc, block;
5189 /* For fields not not tracking in the in-memory inode,
5190 * initialise them to zero for new inodes. */
5191 if (ext4_test_inode_state(inode, EXT4_STATE_NEW))
5192 memset(raw_inode, 0, EXT4_SB(inode->i_sb)->s_inode_size);
5194 ext4_get_inode_flags(ei);
5195 raw_inode->i_mode = cpu_to_le16(inode->i_mode);
5196 if (!(test_opt(inode->i_sb, NO_UID32))) {
5197 raw_inode->i_uid_low = cpu_to_le16(low_16_bits(inode->i_uid));
5198 raw_inode->i_gid_low = cpu_to_le16(low_16_bits(inode->i_gid));
5200 * Fix up interoperability with old kernels. Otherwise, old inodes get
5201 * re-used with the upper 16 bits of the uid/gid intact
5204 raw_inode->i_uid_high =
5205 cpu_to_le16(high_16_bits(inode->i_uid));
5206 raw_inode->i_gid_high =
5207 cpu_to_le16(high_16_bits(inode->i_gid));
5209 raw_inode->i_uid_high = 0;
5210 raw_inode->i_gid_high = 0;
5213 raw_inode->i_uid_low =
5214 cpu_to_le16(fs_high2lowuid(inode->i_uid));
5215 raw_inode->i_gid_low =
5216 cpu_to_le16(fs_high2lowgid(inode->i_gid));
5217 raw_inode->i_uid_high = 0;
5218 raw_inode->i_gid_high = 0;
5220 raw_inode->i_links_count = cpu_to_le16(inode->i_nlink);
5222 EXT4_INODE_SET_XTIME(i_ctime, inode, raw_inode);
5223 EXT4_INODE_SET_XTIME(i_mtime, inode, raw_inode);
5224 EXT4_INODE_SET_XTIME(i_atime, inode, raw_inode);
5225 EXT4_EINODE_SET_XTIME(i_crtime, ei, raw_inode);
5227 if (ext4_inode_blocks_set(handle, raw_inode, ei))
5229 raw_inode->i_dtime = cpu_to_le32(ei->i_dtime);
5230 raw_inode->i_flags = cpu_to_le32(ei->i_flags);
5231 if (EXT4_SB(inode->i_sb)->s_es->s_creator_os !=
5232 cpu_to_le32(EXT4_OS_HURD))
5233 raw_inode->i_file_acl_high =
5234 cpu_to_le16(ei->i_file_acl >> 32);
5235 raw_inode->i_file_acl_lo = cpu_to_le32(ei->i_file_acl);
5236 ext4_isize_set(raw_inode, ei->i_disksize);
5237 if (ei->i_disksize > 0x7fffffffULL) {
5238 struct super_block *sb = inode->i_sb;
5239 if (!EXT4_HAS_RO_COMPAT_FEATURE(sb,
5240 EXT4_FEATURE_RO_COMPAT_LARGE_FILE) ||
5241 EXT4_SB(sb)->s_es->s_rev_level ==
5242 cpu_to_le32(EXT4_GOOD_OLD_REV)) {
5243 /* If this is the first large file
5244 * created, add a flag to the superblock.
5246 err = ext4_journal_get_write_access(handle,
5247 EXT4_SB(sb)->s_sbh);
5250 ext4_update_dynamic_rev(sb);
5251 EXT4_SET_RO_COMPAT_FEATURE(sb,
5252 EXT4_FEATURE_RO_COMPAT_LARGE_FILE);
5254 ext4_handle_sync(handle);
5255 err = ext4_handle_dirty_metadata(handle, NULL,
5256 EXT4_SB(sb)->s_sbh);
5259 raw_inode->i_generation = cpu_to_le32(inode->i_generation);
5260 if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode)) {
5261 if (old_valid_dev(inode->i_rdev)) {
5262 raw_inode->i_block[0] =
5263 cpu_to_le32(old_encode_dev(inode->i_rdev));
5264 raw_inode->i_block[1] = 0;
5266 raw_inode->i_block[0] = 0;
5267 raw_inode->i_block[1] =
5268 cpu_to_le32(new_encode_dev(inode->i_rdev));
5269 raw_inode->i_block[2] = 0;
5272 for (block = 0; block < EXT4_N_BLOCKS; block++)
5273 raw_inode->i_block[block] = ei->i_data[block];
5275 raw_inode->i_disk_version = cpu_to_le32(inode->i_version);
5276 if (ei->i_extra_isize) {
5277 if (EXT4_FITS_IN_INODE(raw_inode, ei, i_version_hi))
5278 raw_inode->i_version_hi =
5279 cpu_to_le32(inode->i_version >> 32);
5280 raw_inode->i_extra_isize = cpu_to_le16(ei->i_extra_isize);
5283 BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
5284 rc = ext4_handle_dirty_metadata(handle, NULL, bh);
5287 ext4_clear_inode_state(inode, EXT4_STATE_NEW);
5289 ext4_update_inode_fsync_trans(handle, inode, 0);
5292 ext4_std_error(inode->i_sb, err);
5297 * ext4_write_inode()
5299 * We are called from a few places:
5301 * - Within generic_file_write() for O_SYNC files.
5302 * Here, there will be no transaction running. We wait for any running
5303 * trasnaction to commit.
5305 * - Within sys_sync(), kupdate and such.
5306 * We wait on commit, if tol to.
5308 * - Within prune_icache() (PF_MEMALLOC == true)
5309 * Here we simply return. We can't afford to block kswapd on the
5312 * In all cases it is actually safe for us to return without doing anything,
5313 * because the inode has been copied into a raw inode buffer in
5314 * ext4_mark_inode_dirty(). This is a correctness thing for O_SYNC and for
5317 * Note that we are absolutely dependent upon all inode dirtiers doing the
5318 * right thing: they *must* call mark_inode_dirty() after dirtying info in
5319 * which we are interested.
5321 * It would be a bug for them to not do this. The code:
5323 * mark_inode_dirty(inode)
5325 * inode->i_size = expr;
5327 * is in error because a kswapd-driven write_inode() could occur while
5328 * `stuff()' is running, and the new i_size will be lost. Plus the inode
5329 * will no longer be on the superblock's dirty inode list.
5331 int ext4_write_inode(struct inode *inode, int wait)
5335 if (current->flags & PF_MEMALLOC)
5338 if (EXT4_SB(inode->i_sb)->s_journal) {
5339 if (ext4_journal_current_handle()) {
5340 jbd_debug(1, "called recursively, non-PF_MEMALLOC!\n");
5348 err = ext4_force_commit(inode->i_sb);
5350 struct ext4_iloc iloc;
5352 err = ext4_get_inode_loc(inode, &iloc);
5356 sync_dirty_buffer(iloc.bh);
5357 if (buffer_req(iloc.bh) && !buffer_uptodate(iloc.bh)) {
5358 ext4_error(inode->i_sb, "IO error syncing inode, "
5359 "inode=%lu, block=%llu", inode->i_ino,
5360 (unsigned long long)iloc.bh->b_blocknr);
5370 * Called from notify_change.
5372 * We want to trap VFS attempts to truncate the file as soon as
5373 * possible. In particular, we want to make sure that when the VFS
5374 * shrinks i_size, we put the inode on the orphan list and modify
5375 * i_disksize immediately, so that during the subsequent flushing of
5376 * dirty pages and freeing of disk blocks, we can guarantee that any
5377 * commit will leave the blocks being flushed in an unused state on
5378 * disk. (On recovery, the inode will get truncated and the blocks will
5379 * be freed, so we have a strong guarantee that no future commit will
5380 * leave these blocks visible to the user.)
5382 * Another thing we have to assure is that if we are in ordered mode
5383 * and inode is still attached to the committing transaction, we must
5384 * we start writeout of all the dirty pages which are being truncated.
5385 * This way we are sure that all the data written in the previous
5386 * transaction are already on disk (truncate waits for pages under
5389 * Called with inode->i_mutex down.
5391 int ext4_setattr(struct dentry *dentry, struct iattr *attr)
5393 struct inode *inode = dentry->d_inode;
5395 const unsigned int ia_valid = attr->ia_valid;
5397 error = inode_change_ok(inode, attr);
5401 if ((ia_valid & ATTR_UID && attr->ia_uid != inode->i_uid) ||
5402 (ia_valid & ATTR_GID && attr->ia_gid != inode->i_gid)) {
5405 /* (user+group)*(old+new) structure, inode write (sb,
5406 * inode block, ? - but truncate inode update has it) */
5407 handle = ext4_journal_start(inode, (EXT4_MAXQUOTAS_INIT_BLOCKS(inode->i_sb)+
5408 EXT4_MAXQUOTAS_DEL_BLOCKS(inode->i_sb))+3);
5409 if (IS_ERR(handle)) {
5410 error = PTR_ERR(handle);
5413 error = vfs_dq_transfer(inode, attr) ? -EDQUOT : 0;
5415 ext4_journal_stop(handle);
5418 /* Update corresponding info in inode so that everything is in
5419 * one transaction */
5420 if (attr->ia_valid & ATTR_UID)
5421 inode->i_uid = attr->ia_uid;
5422 if (attr->ia_valid & ATTR_GID)
5423 inode->i_gid = attr->ia_gid;
5424 error = ext4_mark_inode_dirty(handle, inode);
5425 ext4_journal_stop(handle);
5428 if (attr->ia_valid & ATTR_SIZE) {
5429 if (!(EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL)) {
5430 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
5432 if (attr->ia_size > sbi->s_bitmap_maxbytes) {
5439 if (S_ISREG(inode->i_mode) &&
5440 attr->ia_valid & ATTR_SIZE &&
5441 (attr->ia_size < inode->i_size ||
5442 (EXT4_I(inode)->i_flags & EXT4_EOFBLOCKS_FL))) {
5445 handle = ext4_journal_start(inode, 3);
5446 if (IS_ERR(handle)) {
5447 error = PTR_ERR(handle);
5451 error = ext4_orphan_add(handle, inode);
5452 EXT4_I(inode)->i_disksize = attr->ia_size;
5453 rc = ext4_mark_inode_dirty(handle, inode);
5456 ext4_journal_stop(handle);
5458 if (ext4_should_order_data(inode)) {
5459 error = ext4_begin_ordered_truncate(inode,
5462 /* Do as much error cleanup as possible */
5463 handle = ext4_journal_start(inode, 3);
5464 if (IS_ERR(handle)) {
5465 ext4_orphan_del(NULL, inode);
5468 ext4_orphan_del(handle, inode);
5469 ext4_journal_stop(handle);
5473 /* ext4_truncate will clear the flag */
5474 if ((EXT4_I(inode)->i_flags & EXT4_EOFBLOCKS_FL))
5475 ext4_truncate(inode);
5478 rc = inode_setattr(inode, attr);
5480 /* If inode_setattr's call to ext4_truncate failed to get a
5481 * transaction handle at all, we need to clean up the in-core
5482 * orphan list manually. */
5484 ext4_orphan_del(NULL, inode);
5486 if (!rc && (ia_valid & ATTR_MODE))
5487 rc = ext4_acl_chmod(inode);
5490 ext4_std_error(inode->i_sb, error);
5496 int ext4_getattr(struct vfsmount *mnt, struct dentry *dentry,
5499 struct inode *inode;
5500 unsigned long delalloc_blocks;
5502 inode = dentry->d_inode;
5503 generic_fillattr(inode, stat);
5506 * We can't update i_blocks if the block allocation is delayed
5507 * otherwise in the case of system crash before the real block
5508 * allocation is done, we will have i_blocks inconsistent with
5509 * on-disk file blocks.
5510 * We always keep i_blocks updated together with real
5511 * allocation. But to not confuse with user, stat
5512 * will return the blocks that include the delayed allocation
5513 * blocks for this file.
5515 spin_lock(&EXT4_I(inode)->i_block_reservation_lock);
5516 delalloc_blocks = EXT4_I(inode)->i_reserved_data_blocks;
5517 spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
5519 stat->blocks += (delalloc_blocks << inode->i_sb->s_blocksize_bits)>>9;
5523 static int ext4_indirect_trans_blocks(struct inode *inode, int nrblocks,
5528 /* if nrblocks are contiguous */
5531 * With N contiguous data blocks, it need at most
5532 * N/EXT4_ADDR_PER_BLOCK(inode->i_sb) indirect blocks
5533 * 2 dindirect blocks
5536 indirects = nrblocks / EXT4_ADDR_PER_BLOCK(inode->i_sb);
5537 return indirects + 3;
5540 * if nrblocks are not contiguous, worse case, each block touch
5541 * a indirect block, and each indirect block touch a double indirect
5542 * block, plus a triple indirect block
5544 indirects = nrblocks * 2 + 1;
5548 static int ext4_index_trans_blocks(struct inode *inode, int nrblocks, int chunk)
5550 if (!(EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL))
5551 return ext4_indirect_trans_blocks(inode, nrblocks, chunk);
5552 return ext4_ext_index_trans_blocks(inode, nrblocks, chunk);
5556 * Account for index blocks, block groups bitmaps and block group
5557 * descriptor blocks if modify datablocks and index blocks
5558 * worse case, the indexs blocks spread over different block groups
5560 * If datablocks are discontiguous, they are possible to spread over
5561 * different block groups too. If they are contiuguous, with flexbg,
5562 * they could still across block group boundary.
5564 * Also account for superblock, inode, quota and xattr blocks
5566 int ext4_meta_trans_blocks(struct inode *inode, int nrblocks, int chunk)
5568 ext4_group_t groups, ngroups = ext4_get_groups_count(inode->i_sb);
5574 * How many index blocks need to touch to modify nrblocks?
5575 * The "Chunk" flag indicating whether the nrblocks is
5576 * physically contiguous on disk
5578 * For Direct IO and fallocate, they calls get_block to allocate
5579 * one single extent at a time, so they could set the "Chunk" flag
5581 idxblocks = ext4_index_trans_blocks(inode, nrblocks, chunk);
5586 * Now let's see how many group bitmaps and group descriptors need
5596 if (groups > ngroups)
5598 if (groups > EXT4_SB(inode->i_sb)->s_gdb_count)
5599 gdpblocks = EXT4_SB(inode->i_sb)->s_gdb_count;
5601 /* bitmaps and block group descriptor blocks */
5602 ret += groups + gdpblocks;
5604 /* Blocks for super block, inode, quota and xattr blocks */
5605 ret += EXT4_META_TRANS_BLOCKS(inode->i_sb);
5611 * Calulate the total number of credits to reserve to fit
5612 * the modification of a single pages into a single transaction,
5613 * which may include multiple chunks of block allocations.
5615 * This could be called via ext4_write_begin()
5617 * We need to consider the worse case, when
5618 * one new block per extent.
5620 int ext4_writepage_trans_blocks(struct inode *inode)
5622 int bpp = ext4_journal_blocks_per_page(inode);
5625 ret = ext4_meta_trans_blocks(inode, bpp, 0);
5627 /* Account for data blocks for journalled mode */
5628 if (ext4_should_journal_data(inode))
5634 * Calculate the journal credits for a chunk of data modification.
5636 * This is called from DIO, fallocate or whoever calling
5637 * ext4_get_blocks() to map/allocate a chunk of contiguous disk blocks.
5639 * journal buffers for data blocks are not included here, as DIO
5640 * and fallocate do no need to journal data buffers.
5642 int ext4_chunk_trans_blocks(struct inode *inode, int nrblocks)
5644 return ext4_meta_trans_blocks(inode, nrblocks, 1);
5648 * The caller must have previously called ext4_reserve_inode_write().
5649 * Give this, we know that the caller already has write access to iloc->bh.
5651 int ext4_mark_iloc_dirty(handle_t *handle,
5652 struct inode *inode, struct ext4_iloc *iloc)
5656 if (test_opt(inode->i_sb, I_VERSION))
5657 inode_inc_iversion(inode);
5659 /* the do_update_inode consumes one bh->b_count */
5662 /* ext4_do_update_inode() does jbd2_journal_dirty_metadata */
5663 err = ext4_do_update_inode(handle, inode, iloc);
5669 * On success, We end up with an outstanding reference count against
5670 * iloc->bh. This _must_ be cleaned up later.
5674 ext4_reserve_inode_write(handle_t *handle, struct inode *inode,
5675 struct ext4_iloc *iloc)
5679 err = ext4_get_inode_loc(inode, iloc);
5681 BUFFER_TRACE(iloc->bh, "get_write_access");
5682 err = ext4_journal_get_write_access(handle, iloc->bh);
5688 ext4_std_error(inode->i_sb, err);
5693 * Expand an inode by new_extra_isize bytes.
5694 * Returns 0 on success or negative error number on failure.
5696 static int ext4_expand_extra_isize(struct inode *inode,
5697 unsigned int new_extra_isize,
5698 struct ext4_iloc iloc,
5701 struct ext4_inode *raw_inode;
5702 struct ext4_xattr_ibody_header *header;
5703 struct ext4_xattr_entry *entry;
5705 if (EXT4_I(inode)->i_extra_isize >= new_extra_isize)
5708 raw_inode = ext4_raw_inode(&iloc);
5710 header = IHDR(inode, raw_inode);
5711 entry = IFIRST(header);
5713 /* No extended attributes present */
5714 if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR) ||
5715 header->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC)) {
5716 memset((void *)raw_inode + EXT4_GOOD_OLD_INODE_SIZE, 0,
5718 EXT4_I(inode)->i_extra_isize = new_extra_isize;
5722 /* try to expand with EAs present */
5723 return ext4_expand_extra_isize_ea(inode, new_extra_isize,
5728 * What we do here is to mark the in-core inode as clean with respect to inode
5729 * dirtiness (it may still be data-dirty).
5730 * This means that the in-core inode may be reaped by prune_icache
5731 * without having to perform any I/O. This is a very good thing,
5732 * because *any* task may call prune_icache - even ones which
5733 * have a transaction open against a different journal.
5735 * Is this cheating? Not really. Sure, we haven't written the
5736 * inode out, but prune_icache isn't a user-visible syncing function.
5737 * Whenever the user wants stuff synced (sys_sync, sys_msync, sys_fsync)
5738 * we start and wait on commits.
5740 * Is this efficient/effective? Well, we're being nice to the system
5741 * by cleaning up our inodes proactively so they can be reaped
5742 * without I/O. But we are potentially leaving up to five seconds'
5743 * worth of inodes floating about which prune_icache wants us to
5744 * write out. One way to fix that would be to get prune_icache()
5745 * to do a write_super() to free up some memory. It has the desired
5748 int ext4_mark_inode_dirty(handle_t *handle, struct inode *inode)
5750 struct ext4_iloc iloc;
5751 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
5752 static unsigned int mnt_count;
5756 err = ext4_reserve_inode_write(handle, inode, &iloc);
5757 if (ext4_handle_valid(handle) &&
5758 EXT4_I(inode)->i_extra_isize < sbi->s_want_extra_isize &&
5759 !ext4_test_inode_state(inode, EXT4_STATE_NO_EXPAND)) {
5761 * We need extra buffer credits since we may write into EA block
5762 * with this same handle. If journal_extend fails, then it will
5763 * only result in a minor loss of functionality for that inode.
5764 * If this is felt to be critical, then e2fsck should be run to
5765 * force a large enough s_min_extra_isize.
5767 if ((jbd2_journal_extend(handle,
5768 EXT4_DATA_TRANS_BLOCKS(inode->i_sb))) == 0) {
5769 ret = ext4_expand_extra_isize(inode,
5770 sbi->s_want_extra_isize,
5773 ext4_set_inode_state(inode,
5774 EXT4_STATE_NO_EXPAND);
5776 le16_to_cpu(sbi->s_es->s_mnt_count)) {
5777 ext4_warning(inode->i_sb,
5778 "Unable to expand inode %lu. Delete"
5779 " some EAs or run e2fsck.",
5782 le16_to_cpu(sbi->s_es->s_mnt_count);
5788 err = ext4_mark_iloc_dirty(handle, inode, &iloc);
5793 * ext4_dirty_inode() is called from __mark_inode_dirty()
5795 * We're really interested in the case where a file is being extended.
5796 * i_size has been changed by generic_commit_write() and we thus need
5797 * to include the updated inode in the current transaction.
5799 * Also, vfs_dq_alloc_block() will always dirty the inode when blocks
5800 * are allocated to the file.
5802 * If the inode is marked synchronous, we don't honour that here - doing
5803 * so would cause a commit on atime updates, which we don't bother doing.
5804 * We handle synchronous inodes at the highest possible level.
5806 void ext4_dirty_inode(struct inode *inode)
5810 handle = ext4_journal_start(inode, 2);
5814 ext4_mark_inode_dirty(handle, inode);
5816 ext4_journal_stop(handle);
5823 * Bind an inode's backing buffer_head into this transaction, to prevent
5824 * it from being flushed to disk early. Unlike
5825 * ext4_reserve_inode_write, this leaves behind no bh reference and
5826 * returns no iloc structure, so the caller needs to repeat the iloc
5827 * lookup to mark the inode dirty later.
5829 static int ext4_pin_inode(handle_t *handle, struct inode *inode)
5831 struct ext4_iloc iloc;
5835 err = ext4_get_inode_loc(inode, &iloc);
5837 BUFFER_TRACE(iloc.bh, "get_write_access");
5838 err = jbd2_journal_get_write_access(handle, iloc.bh);
5840 err = ext4_handle_dirty_metadata(handle,
5846 ext4_std_error(inode->i_sb, err);
5851 int ext4_change_inode_journal_flag(struct inode *inode, int val)
5858 * We have to be very careful here: changing a data block's
5859 * journaling status dynamically is dangerous. If we write a
5860 * data block to the journal, change the status and then delete
5861 * that block, we risk forgetting to revoke the old log record
5862 * from the journal and so a subsequent replay can corrupt data.
5863 * So, first we make sure that the journal is empty and that
5864 * nobody is changing anything.
5867 journal = EXT4_JOURNAL(inode);
5870 if (is_journal_aborted(journal))
5873 jbd2_journal_lock_updates(journal);
5874 jbd2_journal_flush(journal);
5877 * OK, there are no updates running now, and all cached data is
5878 * synced to disk. We are now in a completely consistent state
5879 * which doesn't have anything in the journal, and we know that
5880 * no filesystem updates are running, so it is safe to modify
5881 * the inode's in-core data-journaling state flag now.
5885 EXT4_I(inode)->i_flags |= EXT4_JOURNAL_DATA_FL;
5887 EXT4_I(inode)->i_flags &= ~EXT4_JOURNAL_DATA_FL;
5888 ext4_set_aops(inode);
5890 jbd2_journal_unlock_updates(journal);
5892 /* Finally we can mark the inode as dirty. */
5894 handle = ext4_journal_start(inode, 1);
5896 return PTR_ERR(handle);
5898 err = ext4_mark_inode_dirty(handle, inode);
5899 ext4_handle_sync(handle);
5900 ext4_journal_stop(handle);
5901 ext4_std_error(inode->i_sb, err);
5906 static int ext4_bh_unmapped(handle_t *handle, struct buffer_head *bh)
5908 return !buffer_mapped(bh);
5911 int ext4_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
5913 struct page *page = vmf->page;
5918 struct file *file = vma->vm_file;
5919 struct inode *inode = file->f_path.dentry->d_inode;
5920 struct address_space *mapping = inode->i_mapping;
5923 * Get i_alloc_sem to stop truncates messing with the inode. We cannot
5924 * get i_mutex because we are already holding mmap_sem.
5926 down_read(&inode->i_alloc_sem);
5927 size = i_size_read(inode);
5928 if (page->mapping != mapping || size <= page_offset(page)
5929 || !PageUptodate(page)) {
5930 /* page got truncated from under us? */
5934 if (PageMappedToDisk(page))
5937 if (page->index == size >> PAGE_CACHE_SHIFT)
5938 len = size & ~PAGE_CACHE_MASK;
5940 len = PAGE_CACHE_SIZE;
5944 * return if we have all the buffers mapped. This avoid
5945 * the need to call write_begin/write_end which does a
5946 * journal_start/journal_stop which can block and take
5949 if (page_has_buffers(page)) {
5950 if (!walk_page_buffers(NULL, page_buffers(page), 0, len, NULL,
5951 ext4_bh_unmapped)) {
5958 * OK, we need to fill the hole... Do write_begin write_end
5959 * to do block allocation/reservation.We are not holding
5960 * inode.i__mutex here. That allow * parallel write_begin,
5961 * write_end call. lock_page prevent this from happening
5962 * on the same page though
5964 ret = mapping->a_ops->write_begin(file, mapping, page_offset(page),
5965 len, AOP_FLAG_UNINTERRUPTIBLE, &page, &fsdata);
5968 ret = mapping->a_ops->write_end(file, mapping, page_offset(page),
5969 len, len, page, fsdata);
5975 ret = VM_FAULT_SIGBUS;
5976 up_read(&inode->i_alloc_sem);