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 "ext4_jbd2.h"
43 #include "ext4_extents.h"
45 #define MPAGE_DA_EXTENT_TAIL 0x01
47 static inline int ext4_begin_ordered_truncate(struct inode *inode,
50 return jbd2_journal_begin_ordered_truncate(
51 EXT4_SB(inode->i_sb)->s_journal,
52 &EXT4_I(inode)->jinode,
56 static void ext4_invalidatepage(struct page *page, unsigned long offset);
59 * Test whether an inode is a fast symlink.
61 static int ext4_inode_is_fast_symlink(struct inode *inode)
63 int ea_blocks = EXT4_I(inode)->i_file_acl ?
64 (inode->i_sb->s_blocksize >> 9) : 0;
66 return (S_ISLNK(inode->i_mode) && inode->i_blocks - ea_blocks == 0);
70 * The ext4 forget function must perform a revoke if we are freeing data
71 * which has been journaled. Metadata (eg. indirect blocks) must be
72 * revoked in all cases.
74 * "bh" may be NULL: a metadata block may have been freed from memory
75 * but there may still be a record of it in the journal, and that record
76 * still needs to be revoked.
78 * If the handle isn't valid we're not journaling so there's nothing to do.
80 int ext4_forget(handle_t *handle, int is_metadata, struct inode *inode,
81 struct buffer_head *bh, ext4_fsblk_t blocknr)
85 if (!ext4_handle_valid(handle))
90 BUFFER_TRACE(bh, "enter");
92 jbd_debug(4, "forgetting bh %p: is_metadata = %d, mode %o, "
94 bh, is_metadata, inode->i_mode,
95 test_opt(inode->i_sb, DATA_FLAGS));
97 /* Never use the revoke function if we are doing full data
98 * journaling: there is no need to, and a V1 superblock won't
99 * support it. Otherwise, only skip the revoke on un-journaled
102 if (test_opt(inode->i_sb, DATA_FLAGS) == EXT4_MOUNT_JOURNAL_DATA ||
103 (!is_metadata && !ext4_should_journal_data(inode))) {
105 BUFFER_TRACE(bh, "call jbd2_journal_forget");
106 return ext4_journal_forget(handle, bh);
112 * data!=journal && (is_metadata || should_journal_data(inode))
114 BUFFER_TRACE(bh, "call ext4_journal_revoke");
115 err = ext4_journal_revoke(handle, blocknr, bh);
117 ext4_abort(inode->i_sb, __func__,
118 "error %d when attempting revoke", err);
119 BUFFER_TRACE(bh, "exit");
124 * Work out how many blocks we need to proceed with the next chunk of a
125 * truncate transaction.
127 static unsigned long blocks_for_truncate(struct inode *inode)
131 needed = inode->i_blocks >> (inode->i_sb->s_blocksize_bits - 9);
133 /* Give ourselves just enough room to cope with inodes in which
134 * i_blocks is corrupt: we've seen disk corruptions in the past
135 * which resulted in random data in an inode which looked enough
136 * like a regular file for ext4 to try to delete it. Things
137 * will go a bit crazy if that happens, but at least we should
138 * try not to panic the whole kernel. */
142 /* But we need to bound the transaction so we don't overflow the
144 if (needed > EXT4_MAX_TRANS_DATA)
145 needed = EXT4_MAX_TRANS_DATA;
147 return EXT4_DATA_TRANS_BLOCKS(inode->i_sb) + needed;
151 * Truncate transactions can be complex and absolutely huge. So we need to
152 * be able to restart the transaction at a conventient checkpoint to make
153 * sure we don't overflow the journal.
155 * start_transaction gets us a new handle for a truncate transaction,
156 * and extend_transaction tries to extend the existing one a bit. If
157 * extend fails, we need to propagate the failure up and restart the
158 * transaction in the top-level truncate loop. --sct
160 static handle_t *start_transaction(struct inode *inode)
164 result = ext4_journal_start(inode, blocks_for_truncate(inode));
168 ext4_std_error(inode->i_sb, PTR_ERR(result));
173 * Try to extend this transaction for the purposes of truncation.
175 * Returns 0 if we managed to create more room. If we can't create more
176 * room, and the transaction must be restarted we return 1.
178 static int try_to_extend_transaction(handle_t *handle, struct inode *inode)
180 if (!ext4_handle_valid(handle))
182 if (ext4_handle_has_enough_credits(handle, EXT4_RESERVE_TRANS_BLOCKS+1))
184 if (!ext4_journal_extend(handle, blocks_for_truncate(inode)))
190 * Restart the transaction associated with *handle. This does a commit,
191 * so before we call here everything must be consistently dirtied against
194 static int ext4_journal_test_restart(handle_t *handle, struct inode *inode)
196 BUG_ON(EXT4_JOURNAL(inode) == NULL);
197 jbd_debug(2, "restarting handle %p\n", handle);
198 return ext4_journal_restart(handle, blocks_for_truncate(inode));
202 * Called at the last iput() if i_nlink is zero.
204 void ext4_delete_inode(struct inode *inode)
209 if (ext4_should_order_data(inode))
210 ext4_begin_ordered_truncate(inode, 0);
211 truncate_inode_pages(&inode->i_data, 0);
213 if (is_bad_inode(inode))
216 handle = ext4_journal_start(inode, blocks_for_truncate(inode)+3);
217 if (IS_ERR(handle)) {
218 ext4_std_error(inode->i_sb, PTR_ERR(handle));
220 * If we're going to skip the normal cleanup, we still need to
221 * make sure that the in-core orphan linked list is properly
224 ext4_orphan_del(NULL, inode);
229 ext4_handle_sync(handle);
231 err = ext4_mark_inode_dirty(handle, inode);
233 ext4_warning(inode->i_sb, __func__,
234 "couldn't mark inode dirty (err %d)", err);
238 ext4_truncate(inode);
241 * ext4_ext_truncate() doesn't reserve any slop when it
242 * restarts journal transactions; therefore there may not be
243 * enough credits left in the handle to remove the inode from
244 * the orphan list and set the dtime field.
246 if (!ext4_handle_has_enough_credits(handle, 3)) {
247 err = ext4_journal_extend(handle, 3);
249 err = ext4_journal_restart(handle, 3);
251 ext4_warning(inode->i_sb, __func__,
252 "couldn't extend journal (err %d)", err);
254 ext4_journal_stop(handle);
260 * Kill off the orphan record which ext4_truncate created.
261 * AKPM: I think this can be inside the above `if'.
262 * Note that ext4_orphan_del() has to be able to cope with the
263 * deletion of a non-existent orphan - this is because we don't
264 * know if ext4_truncate() actually created an orphan record.
265 * (Well, we could do this if we need to, but heck - it works)
267 ext4_orphan_del(handle, inode);
268 EXT4_I(inode)->i_dtime = get_seconds();
271 * One subtle ordering requirement: if anything has gone wrong
272 * (transaction abort, IO errors, whatever), then we can still
273 * do these next steps (the fs will already have been marked as
274 * having errors), but we can't free the inode if the mark_dirty
277 if (ext4_mark_inode_dirty(handle, inode))
278 /* If that failed, just do the required in-core inode clear. */
281 ext4_free_inode(handle, inode);
282 ext4_journal_stop(handle);
285 clear_inode(inode); /* We must guarantee clearing of inode... */
291 struct buffer_head *bh;
294 static inline void add_chain(Indirect *p, struct buffer_head *bh, __le32 *v)
296 p->key = *(p->p = v);
301 * ext4_block_to_path - parse the block number into array of offsets
302 * @inode: inode in question (we are only interested in its superblock)
303 * @i_block: block number to be parsed
304 * @offsets: array to store the offsets in
305 * @boundary: set this non-zero if the referred-to block is likely to be
306 * followed (on disk) by an indirect block.
308 * To store the locations of file's data ext4 uses a data structure common
309 * for UNIX filesystems - tree of pointers anchored in the inode, with
310 * data blocks at leaves and indirect blocks in intermediate nodes.
311 * This function translates the block number into path in that tree -
312 * return value is the path length and @offsets[n] is the offset of
313 * pointer to (n+1)th node in the nth one. If @block is out of range
314 * (negative or too large) warning is printed and zero returned.
316 * Note: function doesn't find node addresses, so no IO is needed. All
317 * we need to know is the capacity of indirect blocks (taken from the
322 * Portability note: the last comparison (check that we fit into triple
323 * indirect block) is spelled differently, because otherwise on an
324 * architecture with 32-bit longs and 8Kb pages we might get into trouble
325 * if our filesystem had 8Kb blocks. We might use long long, but that would
326 * kill us on x86. Oh, well, at least the sign propagation does not matter -
327 * i_block would have to be negative in the very beginning, so we would not
331 static int ext4_block_to_path(struct inode *inode,
333 ext4_lblk_t offsets[4], int *boundary)
335 int ptrs = EXT4_ADDR_PER_BLOCK(inode->i_sb);
336 int ptrs_bits = EXT4_ADDR_PER_BLOCK_BITS(inode->i_sb);
337 const long direct_blocks = EXT4_NDIR_BLOCKS,
338 indirect_blocks = ptrs,
339 double_blocks = (1 << (ptrs_bits * 2));
344 ext4_warning(inode->i_sb, "ext4_block_to_path", "block < 0");
345 } else if (i_block < direct_blocks) {
346 offsets[n++] = i_block;
347 final = direct_blocks;
348 } else if ((i_block -= direct_blocks) < indirect_blocks) {
349 offsets[n++] = EXT4_IND_BLOCK;
350 offsets[n++] = i_block;
352 } else if ((i_block -= indirect_blocks) < double_blocks) {
353 offsets[n++] = EXT4_DIND_BLOCK;
354 offsets[n++] = i_block >> ptrs_bits;
355 offsets[n++] = i_block & (ptrs - 1);
357 } else if (((i_block -= double_blocks) >> (ptrs_bits * 2)) < ptrs) {
358 offsets[n++] = EXT4_TIND_BLOCK;
359 offsets[n++] = i_block >> (ptrs_bits * 2);
360 offsets[n++] = (i_block >> ptrs_bits) & (ptrs - 1);
361 offsets[n++] = i_block & (ptrs - 1);
364 ext4_warning(inode->i_sb, "ext4_block_to_path",
365 "block %lu > max in inode %lu",
366 i_block + direct_blocks +
367 indirect_blocks + double_blocks, inode->i_ino);
370 *boundary = final - 1 - (i_block & (ptrs - 1));
374 static int __ext4_check_blockref(const char *function, struct inode *inode,
375 __le32 *p, unsigned int max) {
377 unsigned int maxblocks = ext4_blocks_count(EXT4_SB(inode->i_sb)->s_es);
379 while (bref < p+max) {
380 if (unlikely(le32_to_cpu(*bref) >= maxblocks)) {
381 ext4_error(inode->i_sb, function,
382 "block reference %u >= max (%u) "
383 "in inode #%lu, offset=%d",
384 le32_to_cpu(*bref), maxblocks,
385 inode->i_ino, (int)(bref-p));
394 #define ext4_check_indirect_blockref(inode, bh) \
395 __ext4_check_blockref(__func__, inode, (__le32 *)(bh)->b_data, \
396 EXT4_ADDR_PER_BLOCK((inode)->i_sb))
398 #define ext4_check_inode_blockref(inode) \
399 __ext4_check_blockref(__func__, inode, EXT4_I(inode)->i_data, \
403 * ext4_get_branch - read the chain of indirect blocks leading to data
404 * @inode: inode in question
405 * @depth: depth of the chain (1 - direct pointer, etc.)
406 * @offsets: offsets of pointers in inode/indirect blocks
407 * @chain: place to store the result
408 * @err: here we store the error value
410 * Function fills the array of triples <key, p, bh> and returns %NULL
411 * if everything went OK or the pointer to the last filled triple
412 * (incomplete one) otherwise. Upon the return chain[i].key contains
413 * the number of (i+1)-th block in the chain (as it is stored in memory,
414 * i.e. little-endian 32-bit), chain[i].p contains the address of that
415 * number (it points into struct inode for i==0 and into the bh->b_data
416 * for i>0) and chain[i].bh points to the buffer_head of i-th indirect
417 * block for i>0 and NULL for i==0. In other words, it holds the block
418 * numbers of the chain, addresses they were taken from (and where we can
419 * verify that chain did not change) and buffer_heads hosting these
422 * Function stops when it stumbles upon zero pointer (absent block)
423 * (pointer to last triple returned, *@err == 0)
424 * or when it gets an IO error reading an indirect block
425 * (ditto, *@err == -EIO)
426 * or when it reads all @depth-1 indirect blocks successfully and finds
427 * the whole chain, all way to the data (returns %NULL, *err == 0).
429 * Need to be called with
430 * down_read(&EXT4_I(inode)->i_data_sem)
432 static Indirect *ext4_get_branch(struct inode *inode, int depth,
433 ext4_lblk_t *offsets,
434 Indirect chain[4], int *err)
436 struct super_block *sb = inode->i_sb;
438 struct buffer_head *bh;
441 /* i_data is not going away, no lock needed */
442 add_chain(chain, NULL, EXT4_I(inode)->i_data + *offsets);
446 bh = sb_getblk(sb, le32_to_cpu(p->key));
450 if (!bh_uptodate_or_lock(bh)) {
451 if (bh_submit_read(bh) < 0) {
455 /* validate block references */
456 if (ext4_check_indirect_blockref(inode, bh)) {
462 add_chain(++p, bh, (__le32 *)bh->b_data + *++offsets);
476 * ext4_find_near - find a place for allocation with sufficient locality
478 * @ind: descriptor of indirect block.
480 * This function returns the preferred place for block allocation.
481 * It is used when heuristic for sequential allocation fails.
483 * + if there is a block to the left of our position - allocate near it.
484 * + if pointer will live in indirect block - allocate near that block.
485 * + if pointer will live in inode - allocate in the same
488 * In the latter case we colour the starting block by the callers PID to
489 * prevent it from clashing with concurrent allocations for a different inode
490 * in the same block group. The PID is used here so that functionally related
491 * files will be close-by on-disk.
493 * Caller must make sure that @ind is valid and will stay that way.
495 static ext4_fsblk_t ext4_find_near(struct inode *inode, Indirect *ind)
497 struct ext4_inode_info *ei = EXT4_I(inode);
498 __le32 *start = ind->bh ? (__le32 *) ind->bh->b_data : ei->i_data;
500 ext4_fsblk_t bg_start;
501 ext4_fsblk_t last_block;
502 ext4_grpblk_t colour;
503 ext4_group_t block_group;
504 int flex_size = ext4_flex_bg_size(EXT4_SB(inode->i_sb));
506 /* Try to find previous block */
507 for (p = ind->p - 1; p >= start; p--) {
509 return le32_to_cpu(*p);
512 /* No such thing, so let's try location of indirect block */
514 return ind->bh->b_blocknr;
517 * It is going to be referred to from the inode itself? OK, just put it
518 * into the same cylinder group then.
520 block_group = ei->i_block_group;
521 if (flex_size >= EXT4_FLEX_SIZE_DIR_ALLOC_SCHEME) {
522 block_group &= ~(flex_size-1);
523 if (S_ISREG(inode->i_mode))
526 bg_start = ext4_group_first_block_no(inode->i_sb, block_group);
527 last_block = ext4_blocks_count(EXT4_SB(inode->i_sb)->s_es) - 1;
530 * If we are doing delayed allocation, we don't need take
531 * colour into account.
533 if (test_opt(inode->i_sb, DELALLOC))
536 if (bg_start + EXT4_BLOCKS_PER_GROUP(inode->i_sb) <= last_block)
537 colour = (current->pid % 16) *
538 (EXT4_BLOCKS_PER_GROUP(inode->i_sb) / 16);
540 colour = (current->pid % 16) * ((last_block - bg_start) / 16);
541 return bg_start + colour;
545 * ext4_find_goal - find a preferred place for allocation.
547 * @block: block we want
548 * @partial: pointer to the last triple within a chain
550 * Normally this function find the preferred place for block allocation,
553 static ext4_fsblk_t ext4_find_goal(struct inode *inode, ext4_lblk_t block,
557 * XXX need to get goal block from mballoc's data structures
560 return ext4_find_near(inode, partial);
564 * ext4_blks_to_allocate: Look up the block map and count the number
565 * of direct blocks need to be allocated for the given branch.
567 * @branch: chain of indirect blocks
568 * @k: number of blocks need for indirect blocks
569 * @blks: number of data blocks to be mapped.
570 * @blocks_to_boundary: the offset in the indirect block
572 * return the total number of blocks to be allocate, including the
573 * direct and indirect blocks.
575 static int ext4_blks_to_allocate(Indirect *branch, int k, unsigned int blks,
576 int blocks_to_boundary)
578 unsigned int count = 0;
581 * Simple case, [t,d]Indirect block(s) has not allocated yet
582 * then it's clear blocks on that path have not allocated
585 /* right now we don't handle cross boundary allocation */
586 if (blks < blocks_to_boundary + 1)
589 count += blocks_to_boundary + 1;
594 while (count < blks && count <= blocks_to_boundary &&
595 le32_to_cpu(*(branch[0].p + count)) == 0) {
602 * ext4_alloc_blocks: multiple allocate blocks needed for a branch
603 * @indirect_blks: the number of blocks need to allocate for indirect
606 * @new_blocks: on return it will store the new block numbers for
607 * the indirect blocks(if needed) and the first direct block,
608 * @blks: on return it will store the total number of allocated
611 static int ext4_alloc_blocks(handle_t *handle, struct inode *inode,
612 ext4_lblk_t iblock, ext4_fsblk_t goal,
613 int indirect_blks, int blks,
614 ext4_fsblk_t new_blocks[4], int *err)
616 struct ext4_allocation_request ar;
618 unsigned long count = 0, blk_allocated = 0;
620 ext4_fsblk_t current_block = 0;
624 * Here we try to allocate the requested multiple blocks at once,
625 * on a best-effort basis.
626 * To build a branch, we should allocate blocks for
627 * the indirect blocks(if not allocated yet), and at least
628 * the first direct block of this branch. That's the
629 * minimum number of blocks need to allocate(required)
631 /* first we try to allocate the indirect blocks */
632 target = indirect_blks;
635 /* allocating blocks for indirect blocks and direct blocks */
636 current_block = ext4_new_meta_blocks(handle, inode,
642 /* allocate blocks for indirect blocks */
643 while (index < indirect_blks && count) {
644 new_blocks[index++] = current_block++;
649 * save the new block number
650 * for the first direct block
652 new_blocks[index] = current_block;
653 printk(KERN_INFO "%s returned more blocks than "
654 "requested\n", __func__);
660 target = blks - count ;
661 blk_allocated = count;
664 /* Now allocate data blocks */
665 memset(&ar, 0, sizeof(ar));
670 if (S_ISREG(inode->i_mode))
671 /* enable in-core preallocation only for regular files */
672 ar.flags = EXT4_MB_HINT_DATA;
674 current_block = ext4_mb_new_blocks(handle, &ar, err);
676 if (*err && (target == blks)) {
678 * if the allocation failed and we didn't allocate
684 if (target == blks) {
686 * save the new block number
687 * for the first direct block
689 new_blocks[index] = current_block;
691 blk_allocated += ar.len;
694 /* total number of blocks allocated for direct blocks */
699 for (i = 0; i < index; i++)
700 ext4_free_blocks(handle, inode, new_blocks[i], 1, 0);
705 * ext4_alloc_branch - allocate and set up a chain of blocks.
707 * @indirect_blks: number of allocated indirect blocks
708 * @blks: number of allocated direct blocks
709 * @offsets: offsets (in the blocks) to store the pointers to next.
710 * @branch: place to store the chain in.
712 * This function allocates blocks, zeroes out all but the last one,
713 * links them into chain and (if we are synchronous) writes them to disk.
714 * In other words, it prepares a branch that can be spliced onto the
715 * inode. It stores the information about that chain in the branch[], in
716 * the same format as ext4_get_branch() would do. We are calling it after
717 * we had read the existing part of chain and partial points to the last
718 * triple of that (one with zero ->key). Upon the exit we have the same
719 * picture as after the successful ext4_get_block(), except that in one
720 * place chain is disconnected - *branch->p is still zero (we did not
721 * set the last link), but branch->key contains the number that should
722 * be placed into *branch->p to fill that gap.
724 * If allocation fails we free all blocks we've allocated (and forget
725 * their buffer_heads) and return the error value the from failed
726 * ext4_alloc_block() (normally -ENOSPC). Otherwise we set the chain
727 * as described above and return 0.
729 static int ext4_alloc_branch(handle_t *handle, struct inode *inode,
730 ext4_lblk_t iblock, int indirect_blks,
731 int *blks, ext4_fsblk_t goal,
732 ext4_lblk_t *offsets, Indirect *branch)
734 int blocksize = inode->i_sb->s_blocksize;
737 struct buffer_head *bh;
739 ext4_fsblk_t new_blocks[4];
740 ext4_fsblk_t current_block;
742 num = ext4_alloc_blocks(handle, inode, iblock, goal, indirect_blks,
743 *blks, new_blocks, &err);
747 branch[0].key = cpu_to_le32(new_blocks[0]);
749 * metadata blocks and data blocks are allocated.
751 for (n = 1; n <= indirect_blks; n++) {
753 * Get buffer_head for parent block, zero it out
754 * and set the pointer to new one, then send
757 bh = sb_getblk(inode->i_sb, new_blocks[n-1]);
760 BUFFER_TRACE(bh, "call get_create_access");
761 err = ext4_journal_get_create_access(handle, bh);
768 memset(bh->b_data, 0, blocksize);
769 branch[n].p = (__le32 *) bh->b_data + offsets[n];
770 branch[n].key = cpu_to_le32(new_blocks[n]);
771 *branch[n].p = branch[n].key;
772 if (n == indirect_blks) {
773 current_block = new_blocks[n];
775 * End of chain, update the last new metablock of
776 * the chain to point to the new allocated
777 * data blocks numbers
779 for (i=1; i < num; i++)
780 *(branch[n].p + i) = cpu_to_le32(++current_block);
782 BUFFER_TRACE(bh, "marking uptodate");
783 set_buffer_uptodate(bh);
786 BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
787 err = ext4_handle_dirty_metadata(handle, inode, bh);
794 /* Allocation failed, free what we already allocated */
795 for (i = 1; i <= n ; i++) {
796 BUFFER_TRACE(branch[i].bh, "call jbd2_journal_forget");
797 ext4_journal_forget(handle, branch[i].bh);
799 for (i = 0; i < indirect_blks; i++)
800 ext4_free_blocks(handle, inode, new_blocks[i], 1, 0);
802 ext4_free_blocks(handle, inode, new_blocks[i], num, 0);
808 * ext4_splice_branch - splice the allocated branch onto inode.
810 * @block: (logical) number of block we are adding
811 * @chain: chain of indirect blocks (with a missing link - see
813 * @where: location of missing link
814 * @num: number of indirect blocks we are adding
815 * @blks: number of direct blocks we are adding
817 * This function fills the missing link and does all housekeeping needed in
818 * inode (->i_blocks, etc.). In case of success we end up with the full
819 * chain to new block and return 0.
821 static int ext4_splice_branch(handle_t *handle, struct inode *inode,
822 ext4_lblk_t block, Indirect *where, int num, int blks)
826 ext4_fsblk_t current_block;
829 * If we're splicing into a [td]indirect block (as opposed to the
830 * inode) then we need to get write access to the [td]indirect block
834 BUFFER_TRACE(where->bh, "get_write_access");
835 err = ext4_journal_get_write_access(handle, where->bh);
841 *where->p = where->key;
844 * Update the host buffer_head or inode to point to more just allocated
845 * direct blocks blocks
847 if (num == 0 && blks > 1) {
848 current_block = le32_to_cpu(where->key) + 1;
849 for (i = 1; i < blks; i++)
850 *(where->p + i) = cpu_to_le32(current_block++);
853 /* We are done with atomic stuff, now do the rest of housekeeping */
855 inode->i_ctime = ext4_current_time(inode);
856 ext4_mark_inode_dirty(handle, inode);
858 /* had we spliced it onto indirect block? */
861 * If we spliced it onto an indirect block, we haven't
862 * altered the inode. Note however that if it is being spliced
863 * onto an indirect block at the very end of the file (the
864 * file is growing) then we *will* alter the inode to reflect
865 * the new i_size. But that is not done here - it is done in
866 * generic_commit_write->__mark_inode_dirty->ext4_dirty_inode.
868 jbd_debug(5, "splicing indirect only\n");
869 BUFFER_TRACE(where->bh, "call ext4_handle_dirty_metadata");
870 err = ext4_handle_dirty_metadata(handle, inode, where->bh);
875 * OK, we spliced it into the inode itself on a direct block.
876 * Inode was dirtied above.
878 jbd_debug(5, "splicing direct\n");
883 for (i = 1; i <= num; i++) {
884 BUFFER_TRACE(where[i].bh, "call jbd2_journal_forget");
885 ext4_journal_forget(handle, where[i].bh);
886 ext4_free_blocks(handle, inode,
887 le32_to_cpu(where[i-1].key), 1, 0);
889 ext4_free_blocks(handle, inode, le32_to_cpu(where[num].key), blks, 0);
895 * Allocation strategy is simple: if we have to allocate something, we will
896 * have to go the whole way to leaf. So let's do it before attaching anything
897 * to tree, set linkage between the newborn blocks, write them if sync is
898 * required, recheck the path, free and repeat if check fails, otherwise
899 * set the last missing link (that will protect us from any truncate-generated
900 * removals - all blocks on the path are immune now) and possibly force the
901 * write on the parent block.
902 * That has a nice additional property: no special recovery from the failed
903 * allocations is needed - we simply release blocks and do not touch anything
904 * reachable from inode.
906 * `handle' can be NULL if create == 0.
908 * return > 0, # of blocks mapped or allocated.
909 * return = 0, if plain lookup failed.
910 * return < 0, error case.
913 * Need to be called with
914 * down_read(&EXT4_I(inode)->i_data_sem) if not allocating file system block
915 * (ie, create is zero). Otherwise down_write(&EXT4_I(inode)->i_data_sem)
917 static int ext4_get_blocks_handle(handle_t *handle, struct inode *inode,
918 ext4_lblk_t iblock, unsigned int maxblocks,
919 struct buffer_head *bh_result,
920 int create, int extend_disksize)
923 ext4_lblk_t offsets[4];
928 int blocks_to_boundary = 0;
930 struct ext4_inode_info *ei = EXT4_I(inode);
932 ext4_fsblk_t first_block = 0;
936 J_ASSERT(!(EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL));
937 J_ASSERT(handle != NULL || create == 0);
938 depth = ext4_block_to_path(inode, iblock, offsets,
939 &blocks_to_boundary);
944 partial = ext4_get_branch(inode, depth, offsets, chain, &err);
946 /* Simplest case - block found, no allocation needed */
948 first_block = le32_to_cpu(chain[depth - 1].key);
949 clear_buffer_new(bh_result);
952 while (count < maxblocks && count <= blocks_to_boundary) {
955 blk = le32_to_cpu(*(chain[depth-1].p + count));
957 if (blk == first_block + count)
965 /* Next simple case - plain lookup or failed read of indirect block */
966 if (!create || err == -EIO)
970 * Okay, we need to do block allocation.
972 goal = ext4_find_goal(inode, iblock, partial);
974 /* the number of blocks need to allocate for [d,t]indirect blocks */
975 indirect_blks = (chain + depth) - partial - 1;
978 * Next look up the indirect map to count the totoal number of
979 * direct blocks to allocate for this branch.
981 count = ext4_blks_to_allocate(partial, indirect_blks,
982 maxblocks, blocks_to_boundary);
984 * Block out ext4_truncate while we alter the tree
986 err = ext4_alloc_branch(handle, inode, iblock, indirect_blks,
988 offsets + (partial - chain), partial);
991 * The ext4_splice_branch call will free and forget any buffers
992 * on the new chain if there is a failure, but that risks using
993 * up transaction credits, especially for bitmaps where the
994 * credits cannot be returned. Can we handle this somehow? We
995 * may need to return -EAGAIN upwards in the worst case. --sct
998 err = ext4_splice_branch(handle, inode, iblock,
999 partial, indirect_blks, count);
1001 * i_disksize growing is protected by i_data_sem. Don't forget to
1002 * protect it if you're about to implement concurrent
1003 * ext4_get_block() -bzzz
1005 if (!err && extend_disksize) {
1006 disksize = ((loff_t) iblock + count) << inode->i_blkbits;
1007 if (disksize > i_size_read(inode))
1008 disksize = i_size_read(inode);
1009 if (disksize > ei->i_disksize)
1010 ei->i_disksize = disksize;
1015 set_buffer_new(bh_result);
1017 map_bh(bh_result, inode->i_sb, le32_to_cpu(chain[depth-1].key));
1018 if (count > blocks_to_boundary)
1019 set_buffer_boundary(bh_result);
1021 /* Clean up and exit */
1022 partial = chain + depth - 1; /* the whole chain */
1024 while (partial > chain) {
1025 BUFFER_TRACE(partial->bh, "call brelse");
1026 brelse(partial->bh);
1029 BUFFER_TRACE(bh_result, "returned");
1034 qsize_t ext4_get_reserved_space(struct inode *inode)
1036 unsigned long long total;
1038 spin_lock(&EXT4_I(inode)->i_block_reservation_lock);
1039 total = EXT4_I(inode)->i_reserved_data_blocks +
1040 EXT4_I(inode)->i_reserved_meta_blocks;
1041 spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
1046 * Calculate the number of metadata blocks need to reserve
1047 * to allocate @blocks for non extent file based file
1049 static int ext4_indirect_calc_metadata_amount(struct inode *inode, int blocks)
1051 int icap = EXT4_ADDR_PER_BLOCK(inode->i_sb);
1052 int ind_blks, dind_blks, tind_blks;
1054 /* number of new indirect blocks needed */
1055 ind_blks = (blocks + icap - 1) / icap;
1057 dind_blks = (ind_blks + icap - 1) / icap;
1061 return ind_blks + dind_blks + tind_blks;
1065 * Calculate the number of metadata blocks need to reserve
1066 * to allocate given number of blocks
1068 static int ext4_calc_metadata_amount(struct inode *inode, int blocks)
1073 if (EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL)
1074 return ext4_ext_calc_metadata_amount(inode, blocks);
1076 return ext4_indirect_calc_metadata_amount(inode, blocks);
1079 static void ext4_da_update_reserve_space(struct inode *inode, int used)
1081 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
1082 int total, mdb, mdb_free;
1084 spin_lock(&EXT4_I(inode)->i_block_reservation_lock);
1085 /* recalculate the number of metablocks still need to be reserved */
1086 total = EXT4_I(inode)->i_reserved_data_blocks - used;
1087 mdb = ext4_calc_metadata_amount(inode, total);
1089 /* figure out how many metablocks to release */
1090 BUG_ON(mdb > EXT4_I(inode)->i_reserved_meta_blocks);
1091 mdb_free = EXT4_I(inode)->i_reserved_meta_blocks - mdb;
1094 /* Account for allocated meta_blocks */
1095 mdb_free -= EXT4_I(inode)->i_allocated_meta_blocks;
1097 /* update fs dirty blocks counter */
1098 percpu_counter_sub(&sbi->s_dirtyblocks_counter, mdb_free);
1099 EXT4_I(inode)->i_allocated_meta_blocks = 0;
1100 EXT4_I(inode)->i_reserved_meta_blocks = mdb;
1103 /* update per-inode reservations */
1104 BUG_ON(used > EXT4_I(inode)->i_reserved_data_blocks);
1105 EXT4_I(inode)->i_reserved_data_blocks -= used;
1106 spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
1109 * free those over-booking quota for metadata blocks
1112 vfs_dq_release_reservation_block(inode, mdb_free);
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 (!total && (atomic_read(&inode->i_writecount) == 0))
1120 ext4_discard_preallocations(inode);
1124 * The ext4_get_blocks_wrap() function try to look up the requested blocks,
1125 * and returns if the blocks are already mapped.
1127 * Otherwise it takes the write lock of the i_data_sem and allocate blocks
1128 * and store the allocated blocks in the result buffer head and mark it
1131 * If file type is extents based, it will call ext4_ext_get_blocks(),
1132 * Otherwise, call with ext4_get_blocks_handle() to handle indirect mapping
1135 * On success, it returns the number of blocks being mapped or allocate.
1136 * if create==0 and the blocks are pre-allocated and uninitialized block,
1137 * the result buffer head is unmapped. If the create ==1, it will make sure
1138 * the buffer head is mapped.
1140 * It returns 0 if plain look up failed (blocks have not been allocated), in
1141 * that casem, buffer head is unmapped
1143 * It returns the error in case of allocation failure.
1145 int ext4_get_blocks_wrap(handle_t *handle, struct inode *inode, sector_t block,
1146 unsigned int max_blocks, struct buffer_head *bh,
1147 int create, int extend_disksize, int flag)
1151 clear_buffer_mapped(bh);
1154 * Try to see if we can get the block without requesting
1155 * for new file system block.
1157 down_read((&EXT4_I(inode)->i_data_sem));
1158 if (EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL) {
1159 retval = ext4_ext_get_blocks(handle, inode, block, max_blocks,
1162 retval = ext4_get_blocks_handle(handle,
1163 inode, block, max_blocks, bh, 0, 0);
1165 up_read((&EXT4_I(inode)->i_data_sem));
1167 /* If it is only a block(s) look up */
1172 * Returns if the blocks have already allocated
1174 * Note that if blocks have been preallocated
1175 * ext4_ext_get_block() returns th create = 0
1176 * with buffer head unmapped.
1178 if (retval > 0 && buffer_mapped(bh))
1182 * New blocks allocate and/or writing to uninitialized extent
1183 * will possibly result in updating i_data, so we take
1184 * the write lock of i_data_sem, and call get_blocks()
1185 * with create == 1 flag.
1187 down_write((&EXT4_I(inode)->i_data_sem));
1190 * if the caller is from delayed allocation writeout path
1191 * we have already reserved fs blocks for allocation
1192 * let the underlying get_block() function know to
1193 * avoid double accounting
1196 EXT4_I(inode)->i_delalloc_reserved_flag = 1;
1198 * We need to check for EXT4 here because migrate
1199 * could have changed the inode type in between
1201 if (EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL) {
1202 retval = ext4_ext_get_blocks(handle, inode, block, max_blocks,
1203 bh, create, extend_disksize);
1205 retval = ext4_get_blocks_handle(handle, inode, block,
1206 max_blocks, bh, create, extend_disksize);
1208 if (retval > 0 && buffer_new(bh)) {
1210 * We allocated new blocks which will result in
1211 * i_data's format changing. Force the migrate
1212 * to fail by clearing migrate flags
1214 EXT4_I(inode)->i_flags = EXT4_I(inode)->i_flags &
1220 EXT4_I(inode)->i_delalloc_reserved_flag = 0;
1222 * Update reserved blocks/metadata blocks
1223 * after successful block allocation
1224 * which were deferred till now
1226 if ((retval > 0) && buffer_delay(bh))
1227 ext4_da_update_reserve_space(inode, retval);
1230 up_write((&EXT4_I(inode)->i_data_sem));
1234 /* Maximum number of blocks we map for direct IO at once. */
1235 #define DIO_MAX_BLOCKS 4096
1237 int ext4_get_block(struct inode *inode, sector_t iblock,
1238 struct buffer_head *bh_result, int create)
1240 handle_t *handle = ext4_journal_current_handle();
1241 int ret = 0, started = 0;
1242 unsigned max_blocks = bh_result->b_size >> inode->i_blkbits;
1245 if (create && !handle) {
1246 /* Direct IO write... */
1247 if (max_blocks > DIO_MAX_BLOCKS)
1248 max_blocks = DIO_MAX_BLOCKS;
1249 dio_credits = ext4_chunk_trans_blocks(inode, max_blocks);
1250 handle = ext4_journal_start(inode, dio_credits);
1251 if (IS_ERR(handle)) {
1252 ret = PTR_ERR(handle);
1258 ret = ext4_get_blocks_wrap(handle, inode, iblock,
1259 max_blocks, bh_result, create, 0, 0);
1261 bh_result->b_size = (ret << inode->i_blkbits);
1265 ext4_journal_stop(handle);
1271 * `handle' can be NULL if create is zero
1273 struct buffer_head *ext4_getblk(handle_t *handle, struct inode *inode,
1274 ext4_lblk_t block, int create, int *errp)
1276 struct buffer_head dummy;
1279 J_ASSERT(handle != NULL || create == 0);
1282 dummy.b_blocknr = -1000;
1283 buffer_trace_init(&dummy.b_history);
1284 err = ext4_get_blocks_wrap(handle, inode, block, 1,
1285 &dummy, create, 1, 0);
1287 * ext4_get_blocks_handle() returns number of blocks
1288 * mapped. 0 in case of a HOLE.
1296 if (!err && buffer_mapped(&dummy)) {
1297 struct buffer_head *bh;
1298 bh = sb_getblk(inode->i_sb, dummy.b_blocknr);
1303 if (buffer_new(&dummy)) {
1304 J_ASSERT(create != 0);
1305 J_ASSERT(handle != NULL);
1308 * Now that we do not always journal data, we should
1309 * keep in mind whether this should always journal the
1310 * new buffer as metadata. For now, regular file
1311 * writes use ext4_get_block instead, so it's not a
1315 BUFFER_TRACE(bh, "call get_create_access");
1316 fatal = ext4_journal_get_create_access(handle, bh);
1317 if (!fatal && !buffer_uptodate(bh)) {
1318 memset(bh->b_data, 0, inode->i_sb->s_blocksize);
1319 set_buffer_uptodate(bh);
1322 BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
1323 err = ext4_handle_dirty_metadata(handle, inode, bh);
1327 BUFFER_TRACE(bh, "not a new buffer");
1340 struct buffer_head *ext4_bread(handle_t *handle, struct inode *inode,
1341 ext4_lblk_t block, int create, int *err)
1343 struct buffer_head *bh;
1345 bh = ext4_getblk(handle, inode, block, create, err);
1348 if (buffer_uptodate(bh))
1350 ll_rw_block(READ_META, 1, &bh);
1352 if (buffer_uptodate(bh))
1359 static int walk_page_buffers(handle_t *handle,
1360 struct buffer_head *head,
1364 int (*fn)(handle_t *handle,
1365 struct buffer_head *bh))
1367 struct buffer_head *bh;
1368 unsigned block_start, block_end;
1369 unsigned blocksize = head->b_size;
1371 struct buffer_head *next;
1373 for (bh = head, block_start = 0;
1374 ret == 0 && (bh != head || !block_start);
1375 block_start = block_end, bh = next)
1377 next = bh->b_this_page;
1378 block_end = block_start + blocksize;
1379 if (block_end <= from || block_start >= to) {
1380 if (partial && !buffer_uptodate(bh))
1384 err = (*fn)(handle, bh);
1392 * To preserve ordering, it is essential that the hole instantiation and
1393 * the data write be encapsulated in a single transaction. We cannot
1394 * close off a transaction and start a new one between the ext4_get_block()
1395 * and the commit_write(). So doing the jbd2_journal_start at the start of
1396 * prepare_write() is the right place.
1398 * Also, this function can nest inside ext4_writepage() ->
1399 * block_write_full_page(). In that case, we *know* that ext4_writepage()
1400 * has generated enough buffer credits to do the whole page. So we won't
1401 * block on the journal in that case, which is good, because the caller may
1404 * By accident, ext4 can be reentered when a transaction is open via
1405 * quota file writes. If we were to commit the transaction while thus
1406 * reentered, there can be a deadlock - we would be holding a quota
1407 * lock, and the commit would never complete if another thread had a
1408 * transaction open and was blocking on the quota lock - a ranking
1411 * So what we do is to rely on the fact that jbd2_journal_stop/journal_start
1412 * will _not_ run commit under these circumstances because handle->h_ref
1413 * is elevated. We'll still have enough credits for the tiny quotafile
1416 static int do_journal_get_write_access(handle_t *handle,
1417 struct buffer_head *bh)
1419 if (!buffer_mapped(bh) || buffer_freed(bh))
1421 return ext4_journal_get_write_access(handle, bh);
1424 static int ext4_write_begin(struct file *file, struct address_space *mapping,
1425 loff_t pos, unsigned len, unsigned flags,
1426 struct page **pagep, void **fsdata)
1428 struct inode *inode = mapping->host;
1429 int ret, needed_blocks = ext4_writepage_trans_blocks(inode);
1436 trace_mark(ext4_write_begin,
1437 "dev %s ino %lu pos %llu len %u flags %u",
1438 inode->i_sb->s_id, inode->i_ino,
1439 (unsigned long long) pos, len, flags);
1440 index = pos >> PAGE_CACHE_SHIFT;
1441 from = pos & (PAGE_CACHE_SIZE - 1);
1445 handle = ext4_journal_start(inode, needed_blocks);
1446 if (IS_ERR(handle)) {
1447 ret = PTR_ERR(handle);
1451 /* We cannot recurse into the filesystem as the transaction is already
1453 flags |= AOP_FLAG_NOFS;
1455 page = grab_cache_page_write_begin(mapping, index, flags);
1457 ext4_journal_stop(handle);
1463 ret = block_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
1466 if (!ret && ext4_should_journal_data(inode)) {
1467 ret = walk_page_buffers(handle, page_buffers(page),
1468 from, to, NULL, do_journal_get_write_access);
1473 ext4_journal_stop(handle);
1474 page_cache_release(page);
1476 * block_write_begin may have instantiated a few blocks
1477 * outside i_size. Trim these off again. Don't need
1478 * i_size_read because we hold i_mutex.
1480 if (pos + len > inode->i_size)
1481 vmtruncate(inode, inode->i_size);
1484 if (ret == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
1490 /* For write_end() in data=journal mode */
1491 static int write_end_fn(handle_t *handle, struct buffer_head *bh)
1493 if (!buffer_mapped(bh) || buffer_freed(bh))
1495 set_buffer_uptodate(bh);
1496 return ext4_handle_dirty_metadata(handle, NULL, bh);
1500 * We need to pick up the new inode size which generic_commit_write gave us
1501 * `file' can be NULL - eg, when called from page_symlink().
1503 * ext4 never places buffers on inode->i_mapping->private_list. metadata
1504 * buffers are managed internally.
1506 static int ext4_ordered_write_end(struct file *file,
1507 struct address_space *mapping,
1508 loff_t pos, unsigned len, unsigned copied,
1509 struct page *page, void *fsdata)
1511 handle_t *handle = ext4_journal_current_handle();
1512 struct inode *inode = mapping->host;
1515 trace_mark(ext4_ordered_write_end,
1516 "dev %s ino %lu pos %llu len %u copied %u",
1517 inode->i_sb->s_id, inode->i_ino,
1518 (unsigned long long) pos, len, copied);
1519 ret = ext4_jbd2_file_inode(handle, inode);
1524 new_i_size = pos + copied;
1525 if (new_i_size > EXT4_I(inode)->i_disksize) {
1526 ext4_update_i_disksize(inode, new_i_size);
1527 /* We need to mark inode dirty even if
1528 * new_i_size is less that inode->i_size
1529 * bu greater than i_disksize.(hint delalloc)
1531 ext4_mark_inode_dirty(handle, inode);
1534 ret2 = generic_write_end(file, mapping, pos, len, copied,
1540 ret2 = ext4_journal_stop(handle);
1544 return ret ? ret : copied;
1547 static int ext4_writeback_write_end(struct file *file,
1548 struct address_space *mapping,
1549 loff_t pos, unsigned len, unsigned copied,
1550 struct page *page, void *fsdata)
1552 handle_t *handle = ext4_journal_current_handle();
1553 struct inode *inode = mapping->host;
1557 trace_mark(ext4_writeback_write_end,
1558 "dev %s ino %lu pos %llu len %u copied %u",
1559 inode->i_sb->s_id, inode->i_ino,
1560 (unsigned long long) pos, len, copied);
1561 new_i_size = pos + copied;
1562 if (new_i_size > EXT4_I(inode)->i_disksize) {
1563 ext4_update_i_disksize(inode, new_i_size);
1564 /* We need to mark inode dirty even if
1565 * new_i_size is less that inode->i_size
1566 * bu greater than i_disksize.(hint delalloc)
1568 ext4_mark_inode_dirty(handle, inode);
1571 ret2 = generic_write_end(file, mapping, pos, len, copied,
1577 ret2 = ext4_journal_stop(handle);
1581 return ret ? ret : copied;
1584 static int ext4_journalled_write_end(struct file *file,
1585 struct address_space *mapping,
1586 loff_t pos, unsigned len, unsigned copied,
1587 struct page *page, void *fsdata)
1589 handle_t *handle = ext4_journal_current_handle();
1590 struct inode *inode = mapping->host;
1596 trace_mark(ext4_journalled_write_end,
1597 "dev %s ino %lu pos %llu len %u copied %u",
1598 inode->i_sb->s_id, inode->i_ino,
1599 (unsigned long long) pos, len, copied);
1600 from = pos & (PAGE_CACHE_SIZE - 1);
1604 if (!PageUptodate(page))
1606 page_zero_new_buffers(page, from+copied, to);
1609 ret = walk_page_buffers(handle, page_buffers(page), from,
1610 to, &partial, write_end_fn);
1612 SetPageUptodate(page);
1613 new_i_size = pos + copied;
1614 if (new_i_size > inode->i_size)
1615 i_size_write(inode, pos+copied);
1616 EXT4_I(inode)->i_state |= EXT4_STATE_JDATA;
1617 if (new_i_size > EXT4_I(inode)->i_disksize) {
1618 ext4_update_i_disksize(inode, new_i_size);
1619 ret2 = ext4_mark_inode_dirty(handle, inode);
1625 ret2 = ext4_journal_stop(handle);
1628 page_cache_release(page);
1630 return ret ? ret : copied;
1633 static int ext4_da_reserve_space(struct inode *inode, int nrblocks)
1636 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
1637 unsigned long md_needed, mdblocks, total = 0;
1640 * recalculate the amount of metadata blocks to reserve
1641 * in order to allocate nrblocks
1642 * worse case is one extent per block
1645 spin_lock(&EXT4_I(inode)->i_block_reservation_lock);
1646 total = EXT4_I(inode)->i_reserved_data_blocks + nrblocks;
1647 mdblocks = ext4_calc_metadata_amount(inode, total);
1648 BUG_ON(mdblocks < EXT4_I(inode)->i_reserved_meta_blocks);
1650 md_needed = mdblocks - EXT4_I(inode)->i_reserved_meta_blocks;
1651 total = md_needed + nrblocks;
1654 * Make quota reservation here to prevent quota overflow
1655 * later. Real quota accounting is done at pages writeout
1658 if (vfs_dq_reserve_block(inode, total)) {
1659 spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
1663 if (ext4_claim_free_blocks(sbi, total)) {
1664 spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
1665 if (ext4_should_retry_alloc(inode->i_sb, &retries)) {
1669 vfs_dq_release_reservation_block(inode, total);
1672 EXT4_I(inode)->i_reserved_data_blocks += nrblocks;
1673 EXT4_I(inode)->i_reserved_meta_blocks = mdblocks;
1675 spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
1676 return 0; /* success */
1679 static void ext4_da_release_space(struct inode *inode, int to_free)
1681 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
1682 int total, mdb, mdb_free, release;
1685 return; /* Nothing to release, exit */
1687 spin_lock(&EXT4_I(inode)->i_block_reservation_lock);
1689 if (!EXT4_I(inode)->i_reserved_data_blocks) {
1691 * if there is no reserved blocks, but we try to free some
1692 * then the counter is messed up somewhere.
1693 * but since this function is called from invalidate
1694 * page, it's harmless to return without any action
1696 printk(KERN_INFO "ext4 delalloc try to release %d reserved "
1697 "blocks for inode %lu, but there is no reserved "
1698 "data blocks\n", to_free, inode->i_ino);
1699 spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
1703 /* recalculate the number of metablocks still need to be reserved */
1704 total = EXT4_I(inode)->i_reserved_data_blocks - to_free;
1705 mdb = ext4_calc_metadata_amount(inode, total);
1707 /* figure out how many metablocks to release */
1708 BUG_ON(mdb > EXT4_I(inode)->i_reserved_meta_blocks);
1709 mdb_free = EXT4_I(inode)->i_reserved_meta_blocks - mdb;
1711 release = to_free + mdb_free;
1713 /* update fs dirty blocks counter for truncate case */
1714 percpu_counter_sub(&sbi->s_dirtyblocks_counter, release);
1716 /* update per-inode reservations */
1717 BUG_ON(to_free > EXT4_I(inode)->i_reserved_data_blocks);
1718 EXT4_I(inode)->i_reserved_data_blocks -= to_free;
1720 BUG_ON(mdb > EXT4_I(inode)->i_reserved_meta_blocks);
1721 EXT4_I(inode)->i_reserved_meta_blocks = mdb;
1722 spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
1724 vfs_dq_release_reservation_block(inode, release);
1727 static void ext4_da_page_release_reservation(struct page *page,
1728 unsigned long offset)
1731 struct buffer_head *head, *bh;
1732 unsigned int curr_off = 0;
1734 head = page_buffers(page);
1737 unsigned int next_off = curr_off + bh->b_size;
1739 if ((offset <= curr_off) && (buffer_delay(bh))) {
1741 clear_buffer_delay(bh);
1743 curr_off = next_off;
1744 } while ((bh = bh->b_this_page) != head);
1745 ext4_da_release_space(page->mapping->host, to_release);
1749 * Delayed allocation stuff
1752 struct mpage_da_data {
1753 struct inode *inode;
1754 sector_t b_blocknr; /* start block number of extent */
1755 size_t b_size; /* size of extent */
1756 unsigned long b_state; /* state of the extent */
1757 unsigned long first_page, next_page; /* extent of pages */
1758 struct writeback_control *wbc;
1765 * mpage_da_submit_io - walks through extent of pages and try to write
1766 * them with writepage() call back
1768 * @mpd->inode: inode
1769 * @mpd->first_page: first page of the extent
1770 * @mpd->next_page: page after the last page of the extent
1772 * By the time mpage_da_submit_io() is called we expect all blocks
1773 * to be allocated. this may be wrong if allocation failed.
1775 * As pages are already locked by write_cache_pages(), we can't use it
1777 static int mpage_da_submit_io(struct mpage_da_data *mpd)
1780 struct pagevec pvec;
1781 unsigned long index, end;
1782 int ret = 0, err, nr_pages, i;
1783 struct inode *inode = mpd->inode;
1784 struct address_space *mapping = inode->i_mapping;
1786 BUG_ON(mpd->next_page <= mpd->first_page);
1788 * We need to start from the first_page to the next_page - 1
1789 * to make sure we also write the mapped dirty buffer_heads.
1790 * If we look at mpd->b_blocknr we would only be looking
1791 * at the currently mapped buffer_heads.
1793 index = mpd->first_page;
1794 end = mpd->next_page - 1;
1796 pagevec_init(&pvec, 0);
1797 while (index <= end) {
1798 nr_pages = pagevec_lookup(&pvec, mapping, index, PAGEVEC_SIZE);
1801 for (i = 0; i < nr_pages; i++) {
1802 struct page *page = pvec.pages[i];
1804 index = page->index;
1809 BUG_ON(!PageLocked(page));
1810 BUG_ON(PageWriteback(page));
1812 pages_skipped = mpd->wbc->pages_skipped;
1813 err = mapping->a_ops->writepage(page, mpd->wbc);
1814 if (!err && (pages_skipped == mpd->wbc->pages_skipped))
1816 * have successfully written the page
1817 * without skipping the same
1819 mpd->pages_written++;
1821 * In error case, we have to continue because
1822 * remaining pages are still locked
1823 * XXX: unlock and re-dirty them?
1828 pagevec_release(&pvec);
1834 * mpage_put_bnr_to_bhs - walk blocks and assign them actual numbers
1836 * @mpd->inode - inode to walk through
1837 * @exbh->b_blocknr - first block on a disk
1838 * @exbh->b_size - amount of space in bytes
1839 * @logical - first logical block to start assignment with
1841 * the function goes through all passed space and put actual disk
1842 * block numbers into buffer heads, dropping BH_Delay
1844 static void mpage_put_bnr_to_bhs(struct mpage_da_data *mpd, sector_t logical,
1845 struct buffer_head *exbh)
1847 struct inode *inode = mpd->inode;
1848 struct address_space *mapping = inode->i_mapping;
1849 int blocks = exbh->b_size >> inode->i_blkbits;
1850 sector_t pblock = exbh->b_blocknr, cur_logical;
1851 struct buffer_head *head, *bh;
1853 struct pagevec pvec;
1856 index = logical >> (PAGE_CACHE_SHIFT - inode->i_blkbits);
1857 end = (logical + blocks - 1) >> (PAGE_CACHE_SHIFT - inode->i_blkbits);
1858 cur_logical = index << (PAGE_CACHE_SHIFT - inode->i_blkbits);
1860 pagevec_init(&pvec, 0);
1862 while (index <= end) {
1863 /* XXX: optimize tail */
1864 nr_pages = pagevec_lookup(&pvec, mapping, index, PAGEVEC_SIZE);
1867 for (i = 0; i < nr_pages; i++) {
1868 struct page *page = pvec.pages[i];
1870 index = page->index;
1875 BUG_ON(!PageLocked(page));
1876 BUG_ON(PageWriteback(page));
1877 BUG_ON(!page_has_buffers(page));
1879 bh = page_buffers(page);
1882 /* skip blocks out of the range */
1884 if (cur_logical >= logical)
1887 } while ((bh = bh->b_this_page) != head);
1890 if (cur_logical >= logical + blocks)
1892 if (buffer_delay(bh)) {
1893 bh->b_blocknr = pblock;
1894 clear_buffer_delay(bh);
1895 bh->b_bdev = inode->i_sb->s_bdev;
1896 } else if (buffer_unwritten(bh)) {
1897 bh->b_blocknr = pblock;
1898 clear_buffer_unwritten(bh);
1899 set_buffer_mapped(bh);
1901 bh->b_bdev = inode->i_sb->s_bdev;
1902 } else if (buffer_mapped(bh))
1903 BUG_ON(bh->b_blocknr != pblock);
1907 } while ((bh = bh->b_this_page) != head);
1909 pagevec_release(&pvec);
1915 * __unmap_underlying_blocks - just a helper function to unmap
1916 * set of blocks described by @bh
1918 static inline void __unmap_underlying_blocks(struct inode *inode,
1919 struct buffer_head *bh)
1921 struct block_device *bdev = inode->i_sb->s_bdev;
1924 blocks = bh->b_size >> inode->i_blkbits;
1925 for (i = 0; i < blocks; i++)
1926 unmap_underlying_metadata(bdev, bh->b_blocknr + i);
1929 static void ext4_da_block_invalidatepages(struct mpage_da_data *mpd,
1930 sector_t logical, long blk_cnt)
1934 struct pagevec pvec;
1935 struct inode *inode = mpd->inode;
1936 struct address_space *mapping = inode->i_mapping;
1938 index = logical >> (PAGE_CACHE_SHIFT - inode->i_blkbits);
1939 end = (logical + blk_cnt - 1) >>
1940 (PAGE_CACHE_SHIFT - inode->i_blkbits);
1941 while (index <= end) {
1942 nr_pages = pagevec_lookup(&pvec, mapping, index, PAGEVEC_SIZE);
1945 for (i = 0; i < nr_pages; i++) {
1946 struct page *page = pvec.pages[i];
1947 index = page->index;
1952 BUG_ON(!PageLocked(page));
1953 BUG_ON(PageWriteback(page));
1954 block_invalidatepage(page, 0);
1955 ClearPageUptodate(page);
1962 static void ext4_print_free_blocks(struct inode *inode)
1964 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
1965 printk(KERN_EMERG "Total free blocks count %lld\n",
1966 ext4_count_free_blocks(inode->i_sb));
1967 printk(KERN_EMERG "Free/Dirty block details\n");
1968 printk(KERN_EMERG "free_blocks=%lld\n",
1969 (long long)percpu_counter_sum(&sbi->s_freeblocks_counter));
1970 printk(KERN_EMERG "dirty_blocks=%lld\n",
1971 (long long)percpu_counter_sum(&sbi->s_dirtyblocks_counter));
1972 printk(KERN_EMERG "Block reservation details\n");
1973 printk(KERN_EMERG "i_reserved_data_blocks=%u\n",
1974 EXT4_I(inode)->i_reserved_data_blocks);
1975 printk(KERN_EMERG "i_reserved_meta_blocks=%u\n",
1976 EXT4_I(inode)->i_reserved_meta_blocks);
1980 #define EXT4_DELALLOC_RSVED 1
1981 static int ext4_da_get_block_write(struct inode *inode, sector_t iblock,
1982 struct buffer_head *bh_result, int create)
1985 unsigned max_blocks = bh_result->b_size >> inode->i_blkbits;
1986 loff_t disksize = EXT4_I(inode)->i_disksize;
1987 handle_t *handle = NULL;
1989 handle = ext4_journal_current_handle();
1991 ret = ext4_get_blocks_wrap(handle, inode, iblock, max_blocks,
1992 bh_result, create, 0, EXT4_DELALLOC_RSVED);
1996 bh_result->b_size = (ret << inode->i_blkbits);
1998 if (ext4_should_order_data(inode)) {
2000 retval = ext4_jbd2_file_inode(handle, inode);
2003 * Failed to add inode for ordered mode. Don't
2010 * Update on-disk size along with block allocation we don't
2011 * use 'extend_disksize' as size may change within already
2012 * allocated block -bzzz
2014 disksize = ((loff_t) iblock + ret) << inode->i_blkbits;
2015 if (disksize > i_size_read(inode))
2016 disksize = i_size_read(inode);
2017 if (disksize > EXT4_I(inode)->i_disksize) {
2018 ext4_update_i_disksize(inode, disksize);
2019 ret = ext4_mark_inode_dirty(handle, inode);
2026 * mpage_da_map_blocks - go through given space
2028 * @mpd - bh describing space
2030 * The function skips space we know is already mapped to disk blocks.
2033 static int mpage_da_map_blocks(struct mpage_da_data *mpd)
2036 struct buffer_head new;
2040 * We consider only non-mapped and non-allocated blocks
2042 if ((mpd->b_state & (1 << BH_Mapped)) &&
2043 !(mpd->b_state & (1 << BH_Delay)))
2045 new.b_state = mpd->b_state;
2047 new.b_size = mpd->b_size;
2048 next = mpd->b_blocknr;
2050 * If we didn't accumulate anything
2051 * to write simply return
2056 err = ext4_da_get_block_write(mpd->inode, next, &new, 1);
2059 * If get block returns with error we simply
2060 * return. Later writepage will redirty the page and
2061 * writepages will find the dirty page again
2066 if (err == -ENOSPC &&
2067 ext4_count_free_blocks(mpd->inode->i_sb)) {
2073 * get block failure will cause us to loop in
2074 * writepages, because a_ops->writepage won't be able
2075 * to make progress. The page will be redirtied by
2076 * writepage and writepages will again try to write
2079 printk(KERN_EMERG "%s block allocation failed for inode %lu "
2080 "at logical offset %llu with max blocks "
2081 "%zd with error %d\n",
2082 __func__, mpd->inode->i_ino,
2083 (unsigned long long)next,
2084 mpd->b_size >> mpd->inode->i_blkbits, err);
2085 printk(KERN_EMERG "This should not happen.!! "
2086 "Data will be lost\n");
2087 if (err == -ENOSPC) {
2088 ext4_print_free_blocks(mpd->inode);
2090 /* invlaidate all the pages */
2091 ext4_da_block_invalidatepages(mpd, next,
2092 mpd->b_size >> mpd->inode->i_blkbits);
2095 BUG_ON(new.b_size == 0);
2097 if (buffer_new(&new))
2098 __unmap_underlying_blocks(mpd->inode, &new);
2101 * If blocks are delayed marked, we need to
2102 * put actual blocknr and drop delayed bit
2104 if ((mpd->b_state & (1 << BH_Delay)) ||
2105 (mpd->b_state & (1 << BH_Unwritten)))
2106 mpage_put_bnr_to_bhs(mpd, next, &new);
2111 #define BH_FLAGS ((1 << BH_Uptodate) | (1 << BH_Mapped) | \
2112 (1 << BH_Delay) | (1 << BH_Unwritten))
2115 * mpage_add_bh_to_extent - try to add one more block to extent of blocks
2117 * @mpd->lbh - extent of blocks
2118 * @logical - logical number of the block in the file
2119 * @bh - bh of the block (used to access block's state)
2121 * the function is used to collect contig. blocks in same state
2123 static void mpage_add_bh_to_extent(struct mpage_da_data *mpd,
2124 sector_t logical, size_t b_size,
2125 unsigned long b_state)
2128 int nrblocks = mpd->b_size >> mpd->inode->i_blkbits;
2130 /* check if thereserved journal credits might overflow */
2131 if (!(EXT4_I(mpd->inode)->i_flags & EXT4_EXTENTS_FL)) {
2132 if (nrblocks >= EXT4_MAX_TRANS_DATA) {
2134 * With non-extent format we are limited by the journal
2135 * credit available. Total credit needed to insert
2136 * nrblocks contiguous blocks is dependent on the
2137 * nrblocks. So limit nrblocks.
2140 } else if ((nrblocks + (b_size >> mpd->inode->i_blkbits)) >
2141 EXT4_MAX_TRANS_DATA) {
2143 * Adding the new buffer_head would make it cross the
2144 * allowed limit for which we have journal credit
2145 * reserved. So limit the new bh->b_size
2147 b_size = (EXT4_MAX_TRANS_DATA - nrblocks) <<
2148 mpd->inode->i_blkbits;
2149 /* we will do mpage_da_submit_io in the next loop */
2153 * First block in the extent
2155 if (mpd->b_size == 0) {
2156 mpd->b_blocknr = logical;
2157 mpd->b_size = b_size;
2158 mpd->b_state = b_state & BH_FLAGS;
2162 next = mpd->b_blocknr + nrblocks;
2164 * Can we merge the block to our big extent?
2166 if (logical == next && (b_state & BH_FLAGS) == mpd->b_state) {
2167 mpd->b_size += b_size;
2173 * We couldn't merge the block to our extent, so we
2174 * need to flush current extent and start new one
2176 if (mpage_da_map_blocks(mpd) == 0)
2177 mpage_da_submit_io(mpd);
2183 * __mpage_da_writepage - finds extent of pages and blocks
2185 * @page: page to consider
2186 * @wbc: not used, we just follow rules
2189 * The function finds extents of pages and scan them for all blocks.
2191 static int __mpage_da_writepage(struct page *page,
2192 struct writeback_control *wbc, void *data)
2194 struct mpage_da_data *mpd = data;
2195 struct inode *inode = mpd->inode;
2196 struct buffer_head *bh, *head;
2201 * Rest of the page in the page_vec
2202 * redirty then and skip then. We will
2203 * try to to write them again after
2204 * starting a new transaction
2206 redirty_page_for_writepage(wbc, page);
2208 return MPAGE_DA_EXTENT_TAIL;
2211 * Can we merge this page to current extent?
2213 if (mpd->next_page != page->index) {
2215 * Nope, we can't. So, we map non-allocated blocks
2216 * and start IO on them using writepage()
2218 if (mpd->next_page != mpd->first_page) {
2219 if (mpage_da_map_blocks(mpd) == 0)
2220 mpage_da_submit_io(mpd);
2222 * skip rest of the page in the page_vec
2225 redirty_page_for_writepage(wbc, page);
2227 return MPAGE_DA_EXTENT_TAIL;
2231 * Start next extent of pages ...
2233 mpd->first_page = page->index;
2243 mpd->next_page = page->index + 1;
2244 logical = (sector_t) page->index <<
2245 (PAGE_CACHE_SHIFT - inode->i_blkbits);
2247 if (!page_has_buffers(page)) {
2248 mpage_add_bh_to_extent(mpd, logical, PAGE_CACHE_SIZE,
2249 (1 << BH_Dirty) | (1 << BH_Uptodate));
2251 return MPAGE_DA_EXTENT_TAIL;
2254 * Page with regular buffer heads, just add all dirty ones
2256 head = page_buffers(page);
2259 BUG_ON(buffer_locked(bh));
2261 * We need to try to allocate
2262 * unmapped blocks in the same page.
2263 * Otherwise we won't make progress
2264 * with the page in ext4_da_writepage
2266 if (buffer_dirty(bh) &&
2267 (!buffer_mapped(bh) || buffer_delay(bh))) {
2268 mpage_add_bh_to_extent(mpd, logical,
2272 return MPAGE_DA_EXTENT_TAIL;
2273 } else if (buffer_dirty(bh) && (buffer_mapped(bh))) {
2275 * mapped dirty buffer. We need to update
2276 * the b_state because we look at
2277 * b_state in mpage_da_map_blocks. We don't
2278 * update b_size because if we find an
2279 * unmapped buffer_head later we need to
2280 * use the b_state flag of that buffer_head.
2282 if (mpd->b_size == 0)
2283 mpd->b_state = bh->b_state & BH_FLAGS;
2286 } while ((bh = bh->b_this_page) != head);
2293 * this is a special callback for ->write_begin() only
2294 * it's intention is to return mapped block or reserve space
2296 static int ext4_da_get_block_prep(struct inode *inode, sector_t iblock,
2297 struct buffer_head *bh_result, int create)
2300 sector_t invalid_block = ~((sector_t) 0xffff);
2302 if (invalid_block < ext4_blocks_count(EXT4_SB(inode->i_sb)->s_es))
2305 BUG_ON(create == 0);
2306 BUG_ON(bh_result->b_size != inode->i_sb->s_blocksize);
2309 * first, we need to know whether the block is allocated already
2310 * preallocated blocks are unmapped but should treated
2311 * the same as allocated blocks.
2313 ret = ext4_get_blocks_wrap(NULL, inode, iblock, 1, bh_result, 0, 0, 0);
2314 if ((ret == 0) && !buffer_delay(bh_result)) {
2315 /* the block isn't (pre)allocated yet, let's reserve space */
2317 * XXX: __block_prepare_write() unmaps passed block,
2320 ret = ext4_da_reserve_space(inode, 1);
2322 /* not enough space to reserve */
2325 map_bh(bh_result, inode->i_sb, invalid_block);
2326 set_buffer_new(bh_result);
2327 set_buffer_delay(bh_result);
2328 } else if (ret > 0) {
2329 bh_result->b_size = (ret << inode->i_blkbits);
2331 * With sub-block writes into unwritten extents
2332 * we also need to mark the buffer as new so that
2333 * the unwritten parts of the buffer gets correctly zeroed.
2335 if (buffer_unwritten(bh_result))
2336 set_buffer_new(bh_result);
2343 static int ext4_bh_unmapped_or_delay(handle_t *handle, struct buffer_head *bh)
2346 * unmapped buffer is possible for holes.
2347 * delay buffer is possible with delayed allocation
2349 return ((!buffer_mapped(bh) || buffer_delay(bh)) && buffer_dirty(bh));
2352 static int ext4_normal_get_block_write(struct inode *inode, sector_t iblock,
2353 struct buffer_head *bh_result, int create)
2356 unsigned max_blocks = bh_result->b_size >> inode->i_blkbits;
2359 * we don't want to do block allocation in writepage
2360 * so call get_block_wrap with create = 0
2362 ret = ext4_get_blocks_wrap(NULL, inode, iblock, max_blocks,
2363 bh_result, 0, 0, 0);
2365 bh_result->b_size = (ret << inode->i_blkbits);
2372 * get called vi ext4_da_writepages after taking page lock (have journal handle)
2373 * get called via journal_submit_inode_data_buffers (no journal handle)
2374 * get called via shrink_page_list via pdflush (no journal handle)
2375 * or grab_page_cache when doing write_begin (have journal handle)
2377 static int ext4_da_writepage(struct page *page,
2378 struct writeback_control *wbc)
2383 struct buffer_head *page_bufs;
2384 struct inode *inode = page->mapping->host;
2386 trace_mark(ext4_da_writepage,
2387 "dev %s ino %lu page_index %lu",
2388 inode->i_sb->s_id, inode->i_ino, page->index);
2389 size = i_size_read(inode);
2390 if (page->index == size >> PAGE_CACHE_SHIFT)
2391 len = size & ~PAGE_CACHE_MASK;
2393 len = PAGE_CACHE_SIZE;
2395 if (page_has_buffers(page)) {
2396 page_bufs = page_buffers(page);
2397 if (walk_page_buffers(NULL, page_bufs, 0, len, NULL,
2398 ext4_bh_unmapped_or_delay)) {
2400 * We don't want to do block allocation
2401 * So redirty the page and return
2402 * We may reach here when we do a journal commit
2403 * via journal_submit_inode_data_buffers.
2404 * If we don't have mapping block we just ignore
2405 * them. We can also reach here via shrink_page_list
2407 redirty_page_for_writepage(wbc, page);
2413 * The test for page_has_buffers() is subtle:
2414 * We know the page is dirty but it lost buffers. That means
2415 * that at some moment in time after write_begin()/write_end()
2416 * has been called all buffers have been clean and thus they
2417 * must have been written at least once. So they are all
2418 * mapped and we can happily proceed with mapping them
2419 * and writing the page.
2421 * Try to initialize the buffer_heads and check whether
2422 * all are mapped and non delay. We don't want to
2423 * do block allocation here.
2425 ret = block_prepare_write(page, 0, PAGE_CACHE_SIZE,
2426 ext4_normal_get_block_write);
2428 page_bufs = page_buffers(page);
2429 /* check whether all are mapped and non delay */
2430 if (walk_page_buffers(NULL, page_bufs, 0, len, NULL,
2431 ext4_bh_unmapped_or_delay)) {
2432 redirty_page_for_writepage(wbc, page);
2438 * We can't do block allocation here
2439 * so just redity the page and unlock
2442 redirty_page_for_writepage(wbc, page);
2446 /* now mark the buffer_heads as dirty and uptodate */
2447 block_commit_write(page, 0, PAGE_CACHE_SIZE);
2450 if (test_opt(inode->i_sb, NOBH) && ext4_should_writeback_data(inode))
2451 ret = nobh_writepage(page, ext4_normal_get_block_write, wbc);
2453 ret = block_write_full_page(page,
2454 ext4_normal_get_block_write,
2461 * This is called via ext4_da_writepages() to
2462 * calulate the total number of credits to reserve to fit
2463 * a single extent allocation into a single transaction,
2464 * ext4_da_writpeages() will loop calling this before
2465 * the block allocation.
2468 static int ext4_da_writepages_trans_blocks(struct inode *inode)
2470 int max_blocks = EXT4_I(inode)->i_reserved_data_blocks;
2473 * With non-extent format the journal credit needed to
2474 * insert nrblocks contiguous block is dependent on
2475 * number of contiguous block. So we will limit
2476 * number of contiguous block to a sane value
2478 if (!(inode->i_flags & EXT4_EXTENTS_FL) &&
2479 (max_blocks > EXT4_MAX_TRANS_DATA))
2480 max_blocks = EXT4_MAX_TRANS_DATA;
2482 return ext4_chunk_trans_blocks(inode, max_blocks);
2485 static int ext4_da_writepages(struct address_space *mapping,
2486 struct writeback_control *wbc)
2489 int range_whole = 0;
2490 handle_t *handle = NULL;
2491 struct mpage_da_data mpd;
2492 struct inode *inode = mapping->host;
2493 int no_nrwrite_index_update;
2494 int pages_written = 0;
2496 int range_cyclic, cycled = 1, io_done = 0;
2497 int needed_blocks, ret = 0, nr_to_writebump = 0;
2498 struct ext4_sb_info *sbi = EXT4_SB(mapping->host->i_sb);
2500 trace_mark(ext4_da_writepages,
2501 "dev %s ino %lu nr_t_write %ld "
2502 "pages_skipped %ld range_start %llu "
2503 "range_end %llu nonblocking %d "
2504 "for_kupdate %d for_reclaim %d "
2505 "for_writepages %d range_cyclic %d",
2506 inode->i_sb->s_id, inode->i_ino,
2507 wbc->nr_to_write, wbc->pages_skipped,
2508 (unsigned long long) wbc->range_start,
2509 (unsigned long long) wbc->range_end,
2510 wbc->nonblocking, wbc->for_kupdate,
2511 wbc->for_reclaim, wbc->for_writepages,
2515 * No pages to write? This is mainly a kludge to avoid starting
2516 * a transaction for special inodes like journal inode on last iput()
2517 * because that could violate lock ordering on umount
2519 if (!mapping->nrpages || !mapping_tagged(mapping, PAGECACHE_TAG_DIRTY))
2523 * If the filesystem has aborted, it is read-only, so return
2524 * right away instead of dumping stack traces later on that
2525 * will obscure the real source of the problem. We test
2526 * EXT4_MOUNT_ABORT instead of sb->s_flag's MS_RDONLY because
2527 * the latter could be true if the filesystem is mounted
2528 * read-only, and in that case, ext4_da_writepages should
2529 * *never* be called, so if that ever happens, we would want
2532 if (unlikely(sbi->s_mount_opt & EXT4_MOUNT_ABORT))
2536 * Make sure nr_to_write is >= sbi->s_mb_stream_request
2537 * This make sure small files blocks are allocated in
2538 * single attempt. This ensure that small files
2539 * get less fragmented.
2541 if (wbc->nr_to_write < sbi->s_mb_stream_request) {
2542 nr_to_writebump = sbi->s_mb_stream_request - wbc->nr_to_write;
2543 wbc->nr_to_write = sbi->s_mb_stream_request;
2545 if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX)
2548 range_cyclic = wbc->range_cyclic;
2549 if (wbc->range_cyclic) {
2550 index = mapping->writeback_index;
2553 wbc->range_start = index << PAGE_CACHE_SHIFT;
2554 wbc->range_end = LLONG_MAX;
2555 wbc->range_cyclic = 0;
2557 index = wbc->range_start >> PAGE_CACHE_SHIFT;
2560 mpd.inode = mapping->host;
2563 * we don't want write_cache_pages to update
2564 * nr_to_write and writeback_index
2566 no_nrwrite_index_update = wbc->no_nrwrite_index_update;
2567 wbc->no_nrwrite_index_update = 1;
2568 pages_skipped = wbc->pages_skipped;
2571 while (!ret && wbc->nr_to_write > 0) {
2574 * we insert one extent at a time. So we need
2575 * credit needed for single extent allocation.
2576 * journalled mode is currently not supported
2579 BUG_ON(ext4_should_journal_data(inode));
2580 needed_blocks = ext4_da_writepages_trans_blocks(inode);
2582 /* start a new transaction*/
2583 handle = ext4_journal_start(inode, needed_blocks);
2584 if (IS_ERR(handle)) {
2585 ret = PTR_ERR(handle);
2586 printk(KERN_CRIT "%s: jbd2_start: "
2587 "%ld pages, ino %lu; err %d\n", __func__,
2588 wbc->nr_to_write, inode->i_ino, ret);
2590 goto out_writepages;
2594 * Now call __mpage_da_writepage to find the next
2595 * contiguous region of logical blocks that need
2596 * blocks to be allocated by ext4. We don't actually
2597 * submit the blocks for I/O here, even though
2598 * write_cache_pages thinks it will, and will set the
2599 * pages as clean for write before calling
2600 * __mpage_da_writepage().
2608 mpd.pages_written = 0;
2610 ret = write_cache_pages(mapping, wbc, __mpage_da_writepage,
2613 * If we have a contigous extent of pages and we
2614 * haven't done the I/O yet, map the blocks and submit
2617 if (!mpd.io_done && mpd.next_page != mpd.first_page) {
2618 if (mpage_da_map_blocks(&mpd) == 0)
2619 mpage_da_submit_io(&mpd);
2621 ret = MPAGE_DA_EXTENT_TAIL;
2623 wbc->nr_to_write -= mpd.pages_written;
2625 ext4_journal_stop(handle);
2627 if ((mpd.retval == -ENOSPC) && sbi->s_journal) {
2628 /* commit the transaction which would
2629 * free blocks released in the transaction
2632 jbd2_journal_force_commit_nested(sbi->s_journal);
2633 wbc->pages_skipped = pages_skipped;
2635 } else if (ret == MPAGE_DA_EXTENT_TAIL) {
2637 * got one extent now try with
2640 pages_written += mpd.pages_written;
2641 wbc->pages_skipped = pages_skipped;
2644 } else if (wbc->nr_to_write)
2646 * There is no more writeout needed
2647 * or we requested for a noblocking writeout
2648 * and we found the device congested
2652 if (!io_done && !cycled) {
2655 wbc->range_start = index << PAGE_CACHE_SHIFT;
2656 wbc->range_end = mapping->writeback_index - 1;
2659 if (pages_skipped != wbc->pages_skipped)
2660 printk(KERN_EMERG "This should not happen leaving %s "
2661 "with nr_to_write = %ld ret = %d\n",
2662 __func__, wbc->nr_to_write, ret);
2665 index += pages_written;
2666 wbc->range_cyclic = range_cyclic;
2667 if (wbc->range_cyclic || (range_whole && wbc->nr_to_write > 0))
2669 * set the writeback_index so that range_cyclic
2670 * mode will write it back later
2672 mapping->writeback_index = index;
2675 if (!no_nrwrite_index_update)
2676 wbc->no_nrwrite_index_update = 0;
2677 wbc->nr_to_write -= nr_to_writebump;
2678 trace_mark(ext4_da_writepage_result,
2679 "dev %s ino %lu ret %d pages_written %d "
2680 "pages_skipped %ld congestion %d "
2681 "more_io %d no_nrwrite_index_update %d",
2682 inode->i_sb->s_id, inode->i_ino, ret,
2683 pages_written, wbc->pages_skipped,
2684 wbc->encountered_congestion, wbc->more_io,
2685 wbc->no_nrwrite_index_update);
2689 #define FALL_BACK_TO_NONDELALLOC 1
2690 static int ext4_nonda_switch(struct super_block *sb)
2692 s64 free_blocks, dirty_blocks;
2693 struct ext4_sb_info *sbi = EXT4_SB(sb);
2696 * switch to non delalloc mode if we are running low
2697 * on free block. The free block accounting via percpu
2698 * counters can get slightly wrong with percpu_counter_batch getting
2699 * accumulated on each CPU without updating global counters
2700 * Delalloc need an accurate free block accounting. So switch
2701 * to non delalloc when we are near to error range.
2703 free_blocks = percpu_counter_read_positive(&sbi->s_freeblocks_counter);
2704 dirty_blocks = percpu_counter_read_positive(&sbi->s_dirtyblocks_counter);
2705 if (2 * free_blocks < 3 * dirty_blocks ||
2706 free_blocks < (dirty_blocks + EXT4_FREEBLOCKS_WATERMARK)) {
2708 * free block count is less that 150% of dirty blocks
2709 * or free blocks is less that watermark
2716 static int ext4_da_write_begin(struct file *file, struct address_space *mapping,
2717 loff_t pos, unsigned len, unsigned flags,
2718 struct page **pagep, void **fsdata)
2720 int ret, retries = 0;
2724 struct inode *inode = mapping->host;
2727 index = pos >> PAGE_CACHE_SHIFT;
2728 from = pos & (PAGE_CACHE_SIZE - 1);
2731 if (ext4_nonda_switch(inode->i_sb)) {
2732 *fsdata = (void *)FALL_BACK_TO_NONDELALLOC;
2733 return ext4_write_begin(file, mapping, pos,
2734 len, flags, pagep, fsdata);
2736 *fsdata = (void *)0;
2738 trace_mark(ext4_da_write_begin,
2739 "dev %s ino %lu pos %llu len %u flags %u",
2740 inode->i_sb->s_id, inode->i_ino,
2741 (unsigned long long) pos, len, flags);
2744 * With delayed allocation, we don't log the i_disksize update
2745 * if there is delayed block allocation. But we still need
2746 * to journalling the i_disksize update if writes to the end
2747 * of file which has an already mapped buffer.
2749 handle = ext4_journal_start(inode, 1);
2750 if (IS_ERR(handle)) {
2751 ret = PTR_ERR(handle);
2754 /* We cannot recurse into the filesystem as the transaction is already
2756 flags |= AOP_FLAG_NOFS;
2758 page = grab_cache_page_write_begin(mapping, index, flags);
2760 ext4_journal_stop(handle);
2766 ret = block_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
2767 ext4_da_get_block_prep);
2770 ext4_journal_stop(handle);
2771 page_cache_release(page);
2773 * block_write_begin may have instantiated a few blocks
2774 * outside i_size. Trim these off again. Don't need
2775 * i_size_read because we hold i_mutex.
2777 if (pos + len > inode->i_size)
2778 vmtruncate(inode, inode->i_size);
2781 if (ret == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
2788 * Check if we should update i_disksize
2789 * when write to the end of file but not require block allocation
2791 static int ext4_da_should_update_i_disksize(struct page *page,
2792 unsigned long offset)
2794 struct buffer_head *bh;
2795 struct inode *inode = page->mapping->host;
2799 bh = page_buffers(page);
2800 idx = offset >> inode->i_blkbits;
2802 for (i = 0; i < idx; i++)
2803 bh = bh->b_this_page;
2805 if (!buffer_mapped(bh) || (buffer_delay(bh)))
2810 static int ext4_da_write_end(struct file *file,
2811 struct address_space *mapping,
2812 loff_t pos, unsigned len, unsigned copied,
2813 struct page *page, void *fsdata)
2815 struct inode *inode = mapping->host;
2817 handle_t *handle = ext4_journal_current_handle();
2819 unsigned long start, end;
2820 int write_mode = (int)(unsigned long)fsdata;
2822 if (write_mode == FALL_BACK_TO_NONDELALLOC) {
2823 if (ext4_should_order_data(inode)) {
2824 return ext4_ordered_write_end(file, mapping, pos,
2825 len, copied, page, fsdata);
2826 } else if (ext4_should_writeback_data(inode)) {
2827 return ext4_writeback_write_end(file, mapping, pos,
2828 len, copied, page, fsdata);
2834 trace_mark(ext4_da_write_end,
2835 "dev %s ino %lu pos %llu len %u copied %u",
2836 inode->i_sb->s_id, inode->i_ino,
2837 (unsigned long long) pos, len, copied);
2838 start = pos & (PAGE_CACHE_SIZE - 1);
2839 end = start + copied - 1;
2842 * generic_write_end() will run mark_inode_dirty() if i_size
2843 * changes. So let's piggyback the i_disksize mark_inode_dirty
2847 new_i_size = pos + copied;
2848 if (new_i_size > EXT4_I(inode)->i_disksize) {
2849 if (ext4_da_should_update_i_disksize(page, end)) {
2850 down_write(&EXT4_I(inode)->i_data_sem);
2851 if (new_i_size > EXT4_I(inode)->i_disksize) {
2853 * Updating i_disksize when extending file
2854 * without needing block allocation
2856 if (ext4_should_order_data(inode))
2857 ret = ext4_jbd2_file_inode(handle,
2860 EXT4_I(inode)->i_disksize = new_i_size;
2862 up_write(&EXT4_I(inode)->i_data_sem);
2863 /* We need to mark inode dirty even if
2864 * new_i_size is less that inode->i_size
2865 * bu greater than i_disksize.(hint delalloc)
2867 ext4_mark_inode_dirty(handle, inode);
2870 ret2 = generic_write_end(file, mapping, pos, len, copied,
2875 ret2 = ext4_journal_stop(handle);
2879 return ret ? ret : copied;
2882 static void ext4_da_invalidatepage(struct page *page, unsigned long offset)
2885 * Drop reserved blocks
2887 BUG_ON(!PageLocked(page));
2888 if (!page_has_buffers(page))
2891 ext4_da_page_release_reservation(page, offset);
2894 ext4_invalidatepage(page, offset);
2900 * Force all delayed allocation blocks to be allocated for a given inode.
2902 int ext4_alloc_da_blocks(struct inode *inode)
2904 if (!EXT4_I(inode)->i_reserved_data_blocks &&
2905 !EXT4_I(inode)->i_reserved_meta_blocks)
2909 * We do something simple for now. The filemap_flush() will
2910 * also start triggering a write of the data blocks, which is
2911 * not strictly speaking necessary (and for users of
2912 * laptop_mode, not even desirable). However, to do otherwise
2913 * would require replicating code paths in:
2915 * ext4_da_writepages() ->
2916 * write_cache_pages() ---> (via passed in callback function)
2917 * __mpage_da_writepage() -->
2918 * mpage_add_bh_to_extent()
2919 * mpage_da_map_blocks()
2921 * The problem is that write_cache_pages(), located in
2922 * mm/page-writeback.c, marks pages clean in preparation for
2923 * doing I/O, which is not desirable if we're not planning on
2926 * We could call write_cache_pages(), and then redirty all of
2927 * the pages by calling redirty_page_for_writeback() but that
2928 * would be ugly in the extreme. So instead we would need to
2929 * replicate parts of the code in the above functions,
2930 * simplifying them becuase we wouldn't actually intend to
2931 * write out the pages, but rather only collect contiguous
2932 * logical block extents, call the multi-block allocator, and
2933 * then update the buffer heads with the block allocations.
2935 * For now, though, we'll cheat by calling filemap_flush(),
2936 * which will map the blocks, and start the I/O, but not
2937 * actually wait for the I/O to complete.
2939 return filemap_flush(inode->i_mapping);
2943 * bmap() is special. It gets used by applications such as lilo and by
2944 * the swapper to find the on-disk block of a specific piece of data.
2946 * Naturally, this is dangerous if the block concerned is still in the
2947 * journal. If somebody makes a swapfile on an ext4 data-journaling
2948 * filesystem and enables swap, then they may get a nasty shock when the
2949 * data getting swapped to that swapfile suddenly gets overwritten by
2950 * the original zero's written out previously to the journal and
2951 * awaiting writeback in the kernel's buffer cache.
2953 * So, if we see any bmap calls here on a modified, data-journaled file,
2954 * take extra steps to flush any blocks which might be in the cache.
2956 static sector_t ext4_bmap(struct address_space *mapping, sector_t block)
2958 struct inode *inode = mapping->host;
2962 if (mapping_tagged(mapping, PAGECACHE_TAG_DIRTY) &&
2963 test_opt(inode->i_sb, DELALLOC)) {
2965 * With delalloc we want to sync the file
2966 * so that we can make sure we allocate
2969 filemap_write_and_wait(mapping);
2972 if (EXT4_JOURNAL(inode) && EXT4_I(inode)->i_state & EXT4_STATE_JDATA) {
2974 * This is a REALLY heavyweight approach, but the use of
2975 * bmap on dirty files is expected to be extremely rare:
2976 * only if we run lilo or swapon on a freshly made file
2977 * do we expect this to happen.
2979 * (bmap requires CAP_SYS_RAWIO so this does not
2980 * represent an unprivileged user DOS attack --- we'd be
2981 * in trouble if mortal users could trigger this path at
2984 * NB. EXT4_STATE_JDATA is not set on files other than
2985 * regular files. If somebody wants to bmap a directory
2986 * or symlink and gets confused because the buffer
2987 * hasn't yet been flushed to disk, they deserve
2988 * everything they get.
2991 EXT4_I(inode)->i_state &= ~EXT4_STATE_JDATA;
2992 journal = EXT4_JOURNAL(inode);
2993 jbd2_journal_lock_updates(journal);
2994 err = jbd2_journal_flush(journal);
2995 jbd2_journal_unlock_updates(journal);
3001 return generic_block_bmap(mapping, block, ext4_get_block);
3004 static int bget_one(handle_t *handle, struct buffer_head *bh)
3010 static int bput_one(handle_t *handle, struct buffer_head *bh)
3017 * Note that we don't need to start a transaction unless we're journaling data
3018 * because we should have holes filled from ext4_page_mkwrite(). We even don't
3019 * need to file the inode to the transaction's list in ordered mode because if
3020 * we are writing back data added by write(), the inode is already there and if
3021 * we are writing back data modified via mmap(), noone guarantees in which
3022 * transaction the data will hit the disk. In case we are journaling data, we
3023 * cannot start transaction directly because transaction start ranks above page
3024 * lock so we have to do some magic.
3026 * In all journaling modes block_write_full_page() will start the I/O.
3030 * ext4_writepage() -> kmalloc() -> __alloc_pages() -> page_launder() ->
3035 * ext4_file_write() -> generic_file_write() -> __alloc_pages() -> ...
3037 * Same applies to ext4_get_block(). We will deadlock on various things like
3038 * lock_journal and i_data_sem
3040 * Setting PF_MEMALLOC here doesn't work - too many internal memory
3043 * 16May01: If we're reentered then journal_current_handle() will be
3044 * non-zero. We simply *return*.
3046 * 1 July 2001: @@@ FIXME:
3047 * In journalled data mode, a data buffer may be metadata against the
3048 * current transaction. But the same file is part of a shared mapping
3049 * and someone does a writepage() on it.
3051 * We will move the buffer onto the async_data list, but *after* it has
3052 * been dirtied. So there's a small window where we have dirty data on
3055 * Note that this only applies to the last partial page in the file. The
3056 * bit which block_write_full_page() uses prepare/commit for. (That's
3057 * broken code anyway: it's wrong for msync()).
3059 * It's a rare case: affects the final partial page, for journalled data
3060 * where the file is subject to bith write() and writepage() in the same
3061 * transction. To fix it we'll need a custom block_write_full_page().
3062 * We'll probably need that anyway for journalling writepage() output.
3064 * We don't honour synchronous mounts for writepage(). That would be
3065 * disastrous. Any write() or metadata operation will sync the fs for
3069 static int __ext4_normal_writepage(struct page *page,
3070 struct writeback_control *wbc)
3072 struct inode *inode = page->mapping->host;
3074 if (test_opt(inode->i_sb, NOBH))
3075 return nobh_writepage(page,
3076 ext4_normal_get_block_write, wbc);
3078 return block_write_full_page(page,
3079 ext4_normal_get_block_write,
3083 static int ext4_normal_writepage(struct page *page,
3084 struct writeback_control *wbc)
3086 struct inode *inode = page->mapping->host;
3087 loff_t size = i_size_read(inode);
3090 trace_mark(ext4_normal_writepage,
3091 "dev %s ino %lu page_index %lu",
3092 inode->i_sb->s_id, inode->i_ino, page->index);
3093 J_ASSERT(PageLocked(page));
3094 if (page->index == size >> PAGE_CACHE_SHIFT)
3095 len = size & ~PAGE_CACHE_MASK;
3097 len = PAGE_CACHE_SIZE;
3099 if (page_has_buffers(page)) {
3100 /* if page has buffers it should all be mapped
3101 * and allocated. If there are not buffers attached
3102 * to the page we know the page is dirty but it lost
3103 * buffers. That means that at some moment in time
3104 * after write_begin() / write_end() has been called
3105 * all buffers have been clean and thus they must have been
3106 * written at least once. So they are all mapped and we can
3107 * happily proceed with mapping them and writing the page.
3109 BUG_ON(walk_page_buffers(NULL, page_buffers(page), 0, len, NULL,
3110 ext4_bh_unmapped_or_delay));
3113 if (!ext4_journal_current_handle())
3114 return __ext4_normal_writepage(page, wbc);
3116 redirty_page_for_writepage(wbc, page);
3121 static int __ext4_journalled_writepage(struct page *page,
3122 struct writeback_control *wbc)
3124 struct address_space *mapping = page->mapping;
3125 struct inode *inode = mapping->host;
3126 struct buffer_head *page_bufs;
3127 handle_t *handle = NULL;
3131 ret = block_prepare_write(page, 0, PAGE_CACHE_SIZE,
3132 ext4_normal_get_block_write);
3136 page_bufs = page_buffers(page);
3137 walk_page_buffers(handle, page_bufs, 0, PAGE_CACHE_SIZE, NULL,
3139 /* As soon as we unlock the page, it can go away, but we have
3140 * references to buffers so we are safe */
3143 handle = ext4_journal_start(inode, ext4_writepage_trans_blocks(inode));
3144 if (IS_ERR(handle)) {
3145 ret = PTR_ERR(handle);
3149 ret = walk_page_buffers(handle, page_bufs, 0,
3150 PAGE_CACHE_SIZE, NULL, do_journal_get_write_access);
3152 err = walk_page_buffers(handle, page_bufs, 0,
3153 PAGE_CACHE_SIZE, NULL, write_end_fn);
3156 err = ext4_journal_stop(handle);
3160 walk_page_buffers(handle, page_bufs, 0,
3161 PAGE_CACHE_SIZE, NULL, bput_one);
3162 EXT4_I(inode)->i_state |= EXT4_STATE_JDATA;
3171 static int ext4_journalled_writepage(struct page *page,
3172 struct writeback_control *wbc)
3174 struct inode *inode = page->mapping->host;
3175 loff_t size = i_size_read(inode);
3178 trace_mark(ext4_journalled_writepage,
3179 "dev %s ino %lu page_index %lu",
3180 inode->i_sb->s_id, inode->i_ino, page->index);
3181 J_ASSERT(PageLocked(page));
3182 if (page->index == size >> PAGE_CACHE_SHIFT)
3183 len = size & ~PAGE_CACHE_MASK;
3185 len = PAGE_CACHE_SIZE;
3187 if (page_has_buffers(page)) {
3188 /* if page has buffers it should all be mapped
3189 * and allocated. If there are not buffers attached
3190 * to the page we know the page is dirty but it lost
3191 * buffers. That means that at some moment in time
3192 * after write_begin() / write_end() has been called
3193 * all buffers have been clean and thus they must have been
3194 * written at least once. So they are all mapped and we can
3195 * happily proceed with mapping them and writing the page.
3197 BUG_ON(walk_page_buffers(NULL, page_buffers(page), 0, len, NULL,
3198 ext4_bh_unmapped_or_delay));
3201 if (ext4_journal_current_handle())
3204 if (PageChecked(page)) {
3206 * It's mmapped pagecache. Add buffers and journal it. There
3207 * doesn't seem much point in redirtying the page here.
3209 ClearPageChecked(page);
3210 return __ext4_journalled_writepage(page, wbc);
3213 * It may be a page full of checkpoint-mode buffers. We don't
3214 * really know unless we go poke around in the buffer_heads.
3215 * But block_write_full_page will do the right thing.
3217 return block_write_full_page(page,
3218 ext4_normal_get_block_write,
3222 redirty_page_for_writepage(wbc, page);
3227 static int ext4_readpage(struct file *file, struct page *page)
3229 return mpage_readpage(page, ext4_get_block);
3233 ext4_readpages(struct file *file, struct address_space *mapping,
3234 struct list_head *pages, unsigned nr_pages)
3236 return mpage_readpages(mapping, pages, nr_pages, ext4_get_block);
3239 static void ext4_invalidatepage(struct page *page, unsigned long offset)
3241 journal_t *journal = EXT4_JOURNAL(page->mapping->host);
3244 * If it's a full truncate we just forget about the pending dirtying
3247 ClearPageChecked(page);
3250 jbd2_journal_invalidatepage(journal, page, offset);
3252 block_invalidatepage(page, offset);
3255 static int ext4_releasepage(struct page *page, gfp_t wait)
3257 journal_t *journal = EXT4_JOURNAL(page->mapping->host);
3259 WARN_ON(PageChecked(page));
3260 if (!page_has_buffers(page))
3263 return jbd2_journal_try_to_free_buffers(journal, page, wait);
3265 return try_to_free_buffers(page);
3269 * If the O_DIRECT write will extend the file then add this inode to the
3270 * orphan list. So recovery will truncate it back to the original size
3271 * if the machine crashes during the write.
3273 * If the O_DIRECT write is intantiating holes inside i_size and the machine
3274 * crashes then stale disk data _may_ be exposed inside the file. But current
3275 * VFS code falls back into buffered path in that case so we are safe.
3277 static ssize_t ext4_direct_IO(int rw, struct kiocb *iocb,
3278 const struct iovec *iov, loff_t offset,
3279 unsigned long nr_segs)
3281 struct file *file = iocb->ki_filp;
3282 struct inode *inode = file->f_mapping->host;
3283 struct ext4_inode_info *ei = EXT4_I(inode);
3287 size_t count = iov_length(iov, nr_segs);
3290 loff_t final_size = offset + count;
3292 if (final_size > inode->i_size) {
3293 /* Credits for sb + inode write */
3294 handle = ext4_journal_start(inode, 2);
3295 if (IS_ERR(handle)) {
3296 ret = PTR_ERR(handle);
3299 ret = ext4_orphan_add(handle, inode);
3301 ext4_journal_stop(handle);
3305 ei->i_disksize = inode->i_size;
3306 ext4_journal_stop(handle);
3310 ret = blockdev_direct_IO(rw, iocb, inode, inode->i_sb->s_bdev, iov,
3312 ext4_get_block, NULL);
3317 /* Credits for sb + inode write */
3318 handle = ext4_journal_start(inode, 2);
3319 if (IS_ERR(handle)) {
3320 /* This is really bad luck. We've written the data
3321 * but cannot extend i_size. Bail out and pretend
3322 * the write failed... */
3323 ret = PTR_ERR(handle);
3327 ext4_orphan_del(handle, inode);
3329 loff_t end = offset + ret;
3330 if (end > inode->i_size) {
3331 ei->i_disksize = end;
3332 i_size_write(inode, end);
3334 * We're going to return a positive `ret'
3335 * here due to non-zero-length I/O, so there's
3336 * no way of reporting error returns from
3337 * ext4_mark_inode_dirty() to userspace. So
3340 ext4_mark_inode_dirty(handle, inode);
3343 err = ext4_journal_stop(handle);
3352 * Pages can be marked dirty completely asynchronously from ext4's journalling
3353 * activity. By filemap_sync_pte(), try_to_unmap_one(), etc. We cannot do
3354 * much here because ->set_page_dirty is called under VFS locks. The page is
3355 * not necessarily locked.
3357 * We cannot just dirty the page and leave attached buffers clean, because the
3358 * buffers' dirty state is "definitive". We cannot just set the buffers dirty
3359 * or jbddirty because all the journalling code will explode.
3361 * So what we do is to mark the page "pending dirty" and next time writepage
3362 * is called, propagate that into the buffers appropriately.
3364 static int ext4_journalled_set_page_dirty(struct page *page)
3366 SetPageChecked(page);
3367 return __set_page_dirty_nobuffers(page);
3370 static const struct address_space_operations ext4_ordered_aops = {
3371 .readpage = ext4_readpage,
3372 .readpages = ext4_readpages,
3373 .writepage = ext4_normal_writepage,
3374 .sync_page = block_sync_page,
3375 .write_begin = ext4_write_begin,
3376 .write_end = ext4_ordered_write_end,
3378 .invalidatepage = ext4_invalidatepage,
3379 .releasepage = ext4_releasepage,
3380 .direct_IO = ext4_direct_IO,
3381 .migratepage = buffer_migrate_page,
3382 .is_partially_uptodate = block_is_partially_uptodate,
3385 static const struct address_space_operations ext4_writeback_aops = {
3386 .readpage = ext4_readpage,
3387 .readpages = ext4_readpages,
3388 .writepage = ext4_normal_writepage,
3389 .sync_page = block_sync_page,
3390 .write_begin = ext4_write_begin,
3391 .write_end = ext4_writeback_write_end,
3393 .invalidatepage = ext4_invalidatepage,
3394 .releasepage = ext4_releasepage,
3395 .direct_IO = ext4_direct_IO,
3396 .migratepage = buffer_migrate_page,
3397 .is_partially_uptodate = block_is_partially_uptodate,
3400 static const struct address_space_operations ext4_journalled_aops = {
3401 .readpage = ext4_readpage,
3402 .readpages = ext4_readpages,
3403 .writepage = ext4_journalled_writepage,
3404 .sync_page = block_sync_page,
3405 .write_begin = ext4_write_begin,
3406 .write_end = ext4_journalled_write_end,
3407 .set_page_dirty = ext4_journalled_set_page_dirty,
3409 .invalidatepage = ext4_invalidatepage,
3410 .releasepage = ext4_releasepage,
3411 .is_partially_uptodate = block_is_partially_uptodate,
3414 static const struct address_space_operations ext4_da_aops = {
3415 .readpage = ext4_readpage,
3416 .readpages = ext4_readpages,
3417 .writepage = ext4_da_writepage,
3418 .writepages = ext4_da_writepages,
3419 .sync_page = block_sync_page,
3420 .write_begin = ext4_da_write_begin,
3421 .write_end = ext4_da_write_end,
3423 .invalidatepage = ext4_da_invalidatepage,
3424 .releasepage = ext4_releasepage,
3425 .direct_IO = ext4_direct_IO,
3426 .migratepage = buffer_migrate_page,
3427 .is_partially_uptodate = block_is_partially_uptodate,
3430 void ext4_set_aops(struct inode *inode)
3432 if (ext4_should_order_data(inode) &&
3433 test_opt(inode->i_sb, DELALLOC))
3434 inode->i_mapping->a_ops = &ext4_da_aops;
3435 else if (ext4_should_order_data(inode))
3436 inode->i_mapping->a_ops = &ext4_ordered_aops;
3437 else if (ext4_should_writeback_data(inode) &&
3438 test_opt(inode->i_sb, DELALLOC))
3439 inode->i_mapping->a_ops = &ext4_da_aops;
3440 else if (ext4_should_writeback_data(inode))
3441 inode->i_mapping->a_ops = &ext4_writeback_aops;
3443 inode->i_mapping->a_ops = &ext4_journalled_aops;
3447 * ext4_block_truncate_page() zeroes out a mapping from file offset `from'
3448 * up to the end of the block which corresponds to `from'.
3449 * This required during truncate. We need to physically zero the tail end
3450 * of that block so it doesn't yield old data if the file is later grown.
3452 int ext4_block_truncate_page(handle_t *handle,
3453 struct address_space *mapping, loff_t from)
3455 ext4_fsblk_t index = from >> PAGE_CACHE_SHIFT;
3456 unsigned offset = from & (PAGE_CACHE_SIZE-1);
3457 unsigned blocksize, length, pos;
3459 struct inode *inode = mapping->host;
3460 struct buffer_head *bh;
3464 page = grab_cache_page(mapping, from >> PAGE_CACHE_SHIFT);
3468 blocksize = inode->i_sb->s_blocksize;
3469 length = blocksize - (offset & (blocksize - 1));
3470 iblock = index << (PAGE_CACHE_SHIFT - inode->i_sb->s_blocksize_bits);
3473 * For "nobh" option, we can only work if we don't need to
3474 * read-in the page - otherwise we create buffers to do the IO.
3476 if (!page_has_buffers(page) && test_opt(inode->i_sb, NOBH) &&
3477 ext4_should_writeback_data(inode) && PageUptodate(page)) {
3478 zero_user(page, offset, length);
3479 set_page_dirty(page);
3483 if (!page_has_buffers(page))
3484 create_empty_buffers(page, blocksize, 0);
3486 /* Find the buffer that contains "offset" */
3487 bh = page_buffers(page);
3489 while (offset >= pos) {
3490 bh = bh->b_this_page;
3496 if (buffer_freed(bh)) {
3497 BUFFER_TRACE(bh, "freed: skip");
3501 if (!buffer_mapped(bh)) {
3502 BUFFER_TRACE(bh, "unmapped");
3503 ext4_get_block(inode, iblock, bh, 0);
3504 /* unmapped? It's a hole - nothing to do */
3505 if (!buffer_mapped(bh)) {
3506 BUFFER_TRACE(bh, "still unmapped");
3511 /* Ok, it's mapped. Make sure it's up-to-date */
3512 if (PageUptodate(page))
3513 set_buffer_uptodate(bh);
3515 if (!buffer_uptodate(bh)) {
3517 ll_rw_block(READ, 1, &bh);
3519 /* Uhhuh. Read error. Complain and punt. */
3520 if (!buffer_uptodate(bh))
3524 if (ext4_should_journal_data(inode)) {
3525 BUFFER_TRACE(bh, "get write access");
3526 err = ext4_journal_get_write_access(handle, bh);
3531 zero_user(page, offset, length);
3533 BUFFER_TRACE(bh, "zeroed end of block");
3536 if (ext4_should_journal_data(inode)) {
3537 err = ext4_handle_dirty_metadata(handle, inode, bh);
3539 if (ext4_should_order_data(inode))
3540 err = ext4_jbd2_file_inode(handle, inode);
3541 mark_buffer_dirty(bh);
3546 page_cache_release(page);
3551 * Probably it should be a library function... search for first non-zero word
3552 * or memcmp with zero_page, whatever is better for particular architecture.
3555 static inline int all_zeroes(__le32 *p, __le32 *q)
3564 * ext4_find_shared - find the indirect blocks for partial truncation.
3565 * @inode: inode in question
3566 * @depth: depth of the affected branch
3567 * @offsets: offsets of pointers in that branch (see ext4_block_to_path)
3568 * @chain: place to store the pointers to partial indirect blocks
3569 * @top: place to the (detached) top of branch
3571 * This is a helper function used by ext4_truncate().
3573 * When we do truncate() we may have to clean the ends of several
3574 * indirect blocks but leave the blocks themselves alive. Block is
3575 * partially truncated if some data below the new i_size is refered
3576 * from it (and it is on the path to the first completely truncated
3577 * data block, indeed). We have to free the top of that path along
3578 * with everything to the right of the path. Since no allocation
3579 * past the truncation point is possible until ext4_truncate()
3580 * finishes, we may safely do the latter, but top of branch may
3581 * require special attention - pageout below the truncation point
3582 * might try to populate it.
3584 * We atomically detach the top of branch from the tree, store the
3585 * block number of its root in *@top, pointers to buffer_heads of
3586 * partially truncated blocks - in @chain[].bh and pointers to
3587 * their last elements that should not be removed - in
3588 * @chain[].p. Return value is the pointer to last filled element
3591 * The work left to caller to do the actual freeing of subtrees:
3592 * a) free the subtree starting from *@top
3593 * b) free the subtrees whose roots are stored in
3594 * (@chain[i].p+1 .. end of @chain[i].bh->b_data)
3595 * c) free the subtrees growing from the inode past the @chain[0].
3596 * (no partially truncated stuff there). */
3598 static Indirect *ext4_find_shared(struct inode *inode, int depth,
3599 ext4_lblk_t offsets[4], Indirect chain[4], __le32 *top)
3601 Indirect *partial, *p;
3605 /* Make k index the deepest non-null offest + 1 */
3606 for (k = depth; k > 1 && !offsets[k-1]; k--)
3608 partial = ext4_get_branch(inode, k, offsets, chain, &err);
3609 /* Writer: pointers */
3611 partial = chain + k-1;
3613 * If the branch acquired continuation since we've looked at it -
3614 * fine, it should all survive and (new) top doesn't belong to us.
3616 if (!partial->key && *partial->p)
3619 for (p = partial; (p > chain) && all_zeroes((__le32 *) p->bh->b_data, p->p); p--)
3622 * OK, we've found the last block that must survive. The rest of our
3623 * branch should be detached before unlocking. However, if that rest
3624 * of branch is all ours and does not grow immediately from the inode
3625 * it's easier to cheat and just decrement partial->p.
3627 if (p == chain + k - 1 && p > chain) {
3631 /* Nope, don't do this in ext4. Must leave the tree intact */
3638 while (partial > p) {
3639 brelse(partial->bh);
3647 * Zero a number of block pointers in either an inode or an indirect block.
3648 * If we restart the transaction we must again get write access to the
3649 * indirect block for further modification.
3651 * We release `count' blocks on disk, but (last - first) may be greater
3652 * than `count' because there can be holes in there.
3654 static void ext4_clear_blocks(handle_t *handle, struct inode *inode,
3655 struct buffer_head *bh, ext4_fsblk_t block_to_free,
3656 unsigned long count, __le32 *first, __le32 *last)
3659 if (try_to_extend_transaction(handle, inode)) {
3661 BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
3662 ext4_handle_dirty_metadata(handle, inode, bh);
3664 ext4_mark_inode_dirty(handle, inode);
3665 ext4_journal_test_restart(handle, inode);
3667 BUFFER_TRACE(bh, "retaking write access");
3668 ext4_journal_get_write_access(handle, bh);
3673 * Any buffers which are on the journal will be in memory. We find
3674 * them on the hash table so jbd2_journal_revoke() will run jbd2_journal_forget()
3675 * on them. We've already detached each block from the file, so
3676 * bforget() in jbd2_journal_forget() should be safe.
3678 * AKPM: turn on bforget in jbd2_journal_forget()!!!
3680 for (p = first; p < last; p++) {
3681 u32 nr = le32_to_cpu(*p);
3683 struct buffer_head *tbh;
3686 tbh = sb_find_get_block(inode->i_sb, nr);
3687 ext4_forget(handle, 0, inode, tbh, nr);
3691 ext4_free_blocks(handle, inode, block_to_free, count, 0);
3695 * ext4_free_data - free a list of data blocks
3696 * @handle: handle for this transaction
3697 * @inode: inode we are dealing with
3698 * @this_bh: indirect buffer_head which contains *@first and *@last
3699 * @first: array of block numbers
3700 * @last: points immediately past the end of array
3702 * We are freeing all blocks refered from that array (numbers are stored as
3703 * little-endian 32-bit) and updating @inode->i_blocks appropriately.
3705 * We accumulate contiguous runs of blocks to free. Conveniently, if these
3706 * blocks are contiguous then releasing them at one time will only affect one
3707 * or two bitmap blocks (+ group descriptor(s) and superblock) and we won't
3708 * actually use a lot of journal space.
3710 * @this_bh will be %NULL if @first and @last point into the inode's direct
3713 static void ext4_free_data(handle_t *handle, struct inode *inode,
3714 struct buffer_head *this_bh,
3715 __le32 *first, __le32 *last)
3717 ext4_fsblk_t block_to_free = 0; /* Starting block # of a run */
3718 unsigned long count = 0; /* Number of blocks in the run */
3719 __le32 *block_to_free_p = NULL; /* Pointer into inode/ind
3722 ext4_fsblk_t nr; /* Current block # */
3723 __le32 *p; /* Pointer into inode/ind
3724 for current block */
3727 if (this_bh) { /* For indirect block */
3728 BUFFER_TRACE(this_bh, "get_write_access");
3729 err = ext4_journal_get_write_access(handle, this_bh);
3730 /* Important: if we can't update the indirect pointers
3731 * to the blocks, we can't free them. */
3736 for (p = first; p < last; p++) {
3737 nr = le32_to_cpu(*p);
3739 /* accumulate blocks to free if they're contiguous */
3742 block_to_free_p = p;
3744 } else if (nr == block_to_free + count) {
3747 ext4_clear_blocks(handle, inode, this_bh,
3749 count, block_to_free_p, p);
3751 block_to_free_p = p;
3758 ext4_clear_blocks(handle, inode, this_bh, block_to_free,
3759 count, block_to_free_p, p);
3762 BUFFER_TRACE(this_bh, "call ext4_handle_dirty_metadata");
3765 * The buffer head should have an attached journal head at this
3766 * point. However, if the data is corrupted and an indirect
3767 * block pointed to itself, it would have been detached when
3768 * the block was cleared. Check for this instead of OOPSing.
3770 if ((EXT4_JOURNAL(inode) == NULL) || bh2jh(this_bh))
3771 ext4_handle_dirty_metadata(handle, inode, this_bh);
3773 ext4_error(inode->i_sb, __func__,
3774 "circular indirect block detected, "
3775 "inode=%lu, block=%llu",
3777 (unsigned long long) this_bh->b_blocknr);
3782 * ext4_free_branches - free an array of branches
3783 * @handle: JBD handle for this transaction
3784 * @inode: inode we are dealing with
3785 * @parent_bh: the buffer_head which contains *@first and *@last
3786 * @first: array of block numbers
3787 * @last: pointer immediately past the end of array
3788 * @depth: depth of the branches to free
3790 * We are freeing all blocks refered from these branches (numbers are
3791 * stored as little-endian 32-bit) and updating @inode->i_blocks
3794 static void ext4_free_branches(handle_t *handle, struct inode *inode,
3795 struct buffer_head *parent_bh,
3796 __le32 *first, __le32 *last, int depth)
3801 if (ext4_handle_is_aborted(handle))
3805 struct buffer_head *bh;
3806 int addr_per_block = EXT4_ADDR_PER_BLOCK(inode->i_sb);
3808 while (--p >= first) {
3809 nr = le32_to_cpu(*p);
3811 continue; /* A hole */
3813 /* Go read the buffer for the next level down */
3814 bh = sb_bread(inode->i_sb, nr);
3817 * A read failure? Report error and clear slot
3821 ext4_error(inode->i_sb, "ext4_free_branches",
3822 "Read failure, inode=%lu, block=%llu",
3827 /* This zaps the entire block. Bottom up. */
3828 BUFFER_TRACE(bh, "free child branches");
3829 ext4_free_branches(handle, inode, bh,
3830 (__le32 *) bh->b_data,
3831 (__le32 *) bh->b_data + addr_per_block,
3835 * We've probably journalled the indirect block several
3836 * times during the truncate. But it's no longer
3837 * needed and we now drop it from the transaction via
3838 * jbd2_journal_revoke().
3840 * That's easy if it's exclusively part of this
3841 * transaction. But if it's part of the committing
3842 * transaction then jbd2_journal_forget() will simply
3843 * brelse() it. That means that if the underlying
3844 * block is reallocated in ext4_get_block(),
3845 * unmap_underlying_metadata() will find this block
3846 * and will try to get rid of it. damn, damn.
3848 * If this block has already been committed to the
3849 * journal, a revoke record will be written. And
3850 * revoke records must be emitted *before* clearing
3851 * this block's bit in the bitmaps.
3853 ext4_forget(handle, 1, inode, bh, bh->b_blocknr);
3856 * Everything below this this pointer has been
3857 * released. Now let this top-of-subtree go.
3859 * We want the freeing of this indirect block to be
3860 * atomic in the journal with the updating of the
3861 * bitmap block which owns it. So make some room in
3864 * We zero the parent pointer *after* freeing its
3865 * pointee in the bitmaps, so if extend_transaction()
3866 * for some reason fails to put the bitmap changes and
3867 * the release into the same transaction, recovery
3868 * will merely complain about releasing a free block,
3869 * rather than leaking blocks.
3871 if (ext4_handle_is_aborted(handle))
3873 if (try_to_extend_transaction(handle, inode)) {
3874 ext4_mark_inode_dirty(handle, inode);
3875 ext4_journal_test_restart(handle, inode);
3878 ext4_free_blocks(handle, inode, nr, 1, 1);
3882 * The block which we have just freed is
3883 * pointed to by an indirect block: journal it
3885 BUFFER_TRACE(parent_bh, "get_write_access");
3886 if (!ext4_journal_get_write_access(handle,
3889 BUFFER_TRACE(parent_bh,
3890 "call ext4_handle_dirty_metadata");
3891 ext4_handle_dirty_metadata(handle,
3898 /* We have reached the bottom of the tree. */
3899 BUFFER_TRACE(parent_bh, "free data blocks");
3900 ext4_free_data(handle, inode, parent_bh, first, last);
3904 int ext4_can_truncate(struct inode *inode)
3906 if (IS_APPEND(inode) || IS_IMMUTABLE(inode))
3908 if (S_ISREG(inode->i_mode))
3910 if (S_ISDIR(inode->i_mode))
3912 if (S_ISLNK(inode->i_mode))
3913 return !ext4_inode_is_fast_symlink(inode);
3920 * We block out ext4_get_block() block instantiations across the entire
3921 * transaction, and VFS/VM ensures that ext4_truncate() cannot run
3922 * simultaneously on behalf of the same inode.
3924 * As we work through the truncate and commmit bits of it to the journal there
3925 * is one core, guiding principle: the file's tree must always be consistent on
3926 * disk. We must be able to restart the truncate after a crash.
3928 * The file's tree may be transiently inconsistent in memory (although it
3929 * probably isn't), but whenever we close off and commit a journal transaction,
3930 * the contents of (the filesystem + the journal) must be consistent and
3931 * restartable. It's pretty simple, really: bottom up, right to left (although
3932 * left-to-right works OK too).
3934 * Note that at recovery time, journal replay occurs *before* the restart of
3935 * truncate against the orphan inode list.
3937 * The committed inode has the new, desired i_size (which is the same as
3938 * i_disksize in this case). After a crash, ext4_orphan_cleanup() will see
3939 * that this inode's truncate did not complete and it will again call
3940 * ext4_truncate() to have another go. So there will be instantiated blocks
3941 * to the right of the truncation point in a crashed ext4 filesystem. But
3942 * that's fine - as long as they are linked from the inode, the post-crash
3943 * ext4_truncate() run will find them and release them.
3945 void ext4_truncate(struct inode *inode)
3948 struct ext4_inode_info *ei = EXT4_I(inode);
3949 __le32 *i_data = ei->i_data;
3950 int addr_per_block = EXT4_ADDR_PER_BLOCK(inode->i_sb);
3951 struct address_space *mapping = inode->i_mapping;
3952 ext4_lblk_t offsets[4];
3957 ext4_lblk_t last_block;
3958 unsigned blocksize = inode->i_sb->s_blocksize;
3960 if (!ext4_can_truncate(inode))
3963 if (inode->i_size == 0 && !test_opt(inode->i_sb, NO_AUTO_DA_ALLOC))
3964 ei->i_state |= EXT4_STATE_DA_ALLOC_CLOSE;
3966 if (EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL) {
3967 ext4_ext_truncate(inode);
3971 handle = start_transaction(inode);
3973 return; /* AKPM: return what? */
3975 last_block = (inode->i_size + blocksize-1)
3976 >> EXT4_BLOCK_SIZE_BITS(inode->i_sb);
3978 if (inode->i_size & (blocksize - 1))
3979 if (ext4_block_truncate_page(handle, mapping, inode->i_size))
3982 n = ext4_block_to_path(inode, last_block, offsets, NULL);
3984 goto out_stop; /* error */
3987 * OK. This truncate is going to happen. We add the inode to the
3988 * orphan list, so that if this truncate spans multiple transactions,
3989 * and we crash, we will resume the truncate when the filesystem
3990 * recovers. It also marks the inode dirty, to catch the new size.
3992 * Implication: the file must always be in a sane, consistent
3993 * truncatable state while each transaction commits.
3995 if (ext4_orphan_add(handle, inode))
3999 * From here we block out all ext4_get_block() callers who want to
4000 * modify the block allocation tree.
4002 down_write(&ei->i_data_sem);
4004 ext4_discard_preallocations(inode);
4007 * The orphan list entry will now protect us from any crash which
4008 * occurs before the truncate completes, so it is now safe to propagate
4009 * the new, shorter inode size (held for now in i_size) into the
4010 * on-disk inode. We do this via i_disksize, which is the value which
4011 * ext4 *really* writes onto the disk inode.
4013 ei->i_disksize = inode->i_size;
4015 if (n == 1) { /* direct blocks */
4016 ext4_free_data(handle, inode, NULL, i_data+offsets[0],
4017 i_data + EXT4_NDIR_BLOCKS);
4021 partial = ext4_find_shared(inode, n, offsets, chain, &nr);
4022 /* Kill the top of shared branch (not detached) */
4024 if (partial == chain) {
4025 /* Shared branch grows from the inode */
4026 ext4_free_branches(handle, inode, NULL,
4027 &nr, &nr+1, (chain+n-1) - partial);
4030 * We mark the inode dirty prior to restart,
4031 * and prior to stop. No need for it here.
4034 /* Shared branch grows from an indirect block */
4035 BUFFER_TRACE(partial->bh, "get_write_access");
4036 ext4_free_branches(handle, inode, partial->bh,
4038 partial->p+1, (chain+n-1) - partial);
4041 /* Clear the ends of indirect blocks on the shared branch */
4042 while (partial > chain) {
4043 ext4_free_branches(handle, inode, partial->bh, partial->p + 1,
4044 (__le32*)partial->bh->b_data+addr_per_block,
4045 (chain+n-1) - partial);
4046 BUFFER_TRACE(partial->bh, "call brelse");
4047 brelse (partial->bh);
4051 /* Kill the remaining (whole) subtrees */
4052 switch (offsets[0]) {
4054 nr = i_data[EXT4_IND_BLOCK];
4056 ext4_free_branches(handle, inode, NULL, &nr, &nr+1, 1);
4057 i_data[EXT4_IND_BLOCK] = 0;
4059 case EXT4_IND_BLOCK:
4060 nr = i_data[EXT4_DIND_BLOCK];
4062 ext4_free_branches(handle, inode, NULL, &nr, &nr+1, 2);
4063 i_data[EXT4_DIND_BLOCK] = 0;
4065 case EXT4_DIND_BLOCK:
4066 nr = i_data[EXT4_TIND_BLOCK];
4068 ext4_free_branches(handle, inode, NULL, &nr, &nr+1, 3);
4069 i_data[EXT4_TIND_BLOCK] = 0;
4071 case EXT4_TIND_BLOCK:
4075 up_write(&ei->i_data_sem);
4076 inode->i_mtime = inode->i_ctime = ext4_current_time(inode);
4077 ext4_mark_inode_dirty(handle, inode);
4080 * In a multi-transaction truncate, we only make the final transaction
4084 ext4_handle_sync(handle);
4087 * If this was a simple ftruncate(), and the file will remain alive
4088 * then we need to clear up the orphan record which we created above.
4089 * However, if this was a real unlink then we were called by
4090 * ext4_delete_inode(), and we allow that function to clean up the
4091 * orphan info for us.
4094 ext4_orphan_del(handle, inode);
4096 ext4_journal_stop(handle);
4100 * ext4_get_inode_loc returns with an extra refcount against the inode's
4101 * underlying buffer_head on success. If 'in_mem' is true, we have all
4102 * data in memory that is needed to recreate the on-disk version of this
4105 static int __ext4_get_inode_loc(struct inode *inode,
4106 struct ext4_iloc *iloc, int in_mem)
4108 struct ext4_group_desc *gdp;
4109 struct buffer_head *bh;
4110 struct super_block *sb = inode->i_sb;
4112 int inodes_per_block, inode_offset;
4115 if (!ext4_valid_inum(sb, inode->i_ino))
4118 iloc->block_group = (inode->i_ino - 1) / EXT4_INODES_PER_GROUP(sb);
4119 gdp = ext4_get_group_desc(sb, iloc->block_group, NULL);
4124 * Figure out the offset within the block group inode table
4126 inodes_per_block = (EXT4_BLOCK_SIZE(sb) / EXT4_INODE_SIZE(sb));
4127 inode_offset = ((inode->i_ino - 1) %
4128 EXT4_INODES_PER_GROUP(sb));
4129 block = ext4_inode_table(sb, gdp) + (inode_offset / inodes_per_block);
4130 iloc->offset = (inode_offset % inodes_per_block) * EXT4_INODE_SIZE(sb);
4132 bh = sb_getblk(sb, block);
4134 ext4_error(sb, "ext4_get_inode_loc", "unable to read "
4135 "inode block - inode=%lu, block=%llu",
4136 inode->i_ino, block);
4139 if (!buffer_uptodate(bh)) {
4143 * If the buffer has the write error flag, we have failed
4144 * to write out another inode in the same block. In this
4145 * case, we don't have to read the block because we may
4146 * read the old inode data successfully.
4148 if (buffer_write_io_error(bh) && !buffer_uptodate(bh))
4149 set_buffer_uptodate(bh);
4151 if (buffer_uptodate(bh)) {
4152 /* someone brought it uptodate while we waited */
4158 * If we have all information of the inode in memory and this
4159 * is the only valid inode in the block, we need not read the
4163 struct buffer_head *bitmap_bh;
4166 start = inode_offset & ~(inodes_per_block - 1);
4168 /* Is the inode bitmap in cache? */
4169 bitmap_bh = sb_getblk(sb, ext4_inode_bitmap(sb, gdp));
4174 * If the inode bitmap isn't in cache then the
4175 * optimisation may end up performing two reads instead
4176 * of one, so skip it.
4178 if (!buffer_uptodate(bitmap_bh)) {
4182 for (i = start; i < start + inodes_per_block; i++) {
4183 if (i == inode_offset)
4185 if (ext4_test_bit(i, bitmap_bh->b_data))
4189 if (i == start + inodes_per_block) {
4190 /* all other inodes are free, so skip I/O */
4191 memset(bh->b_data, 0, bh->b_size);
4192 set_buffer_uptodate(bh);
4200 * If we need to do any I/O, try to pre-readahead extra
4201 * blocks from the inode table.
4203 if (EXT4_SB(sb)->s_inode_readahead_blks) {
4204 ext4_fsblk_t b, end, table;
4207 table = ext4_inode_table(sb, gdp);
4208 /* s_inode_readahead_blks is always a power of 2 */
4209 b = block & ~(EXT4_SB(sb)->s_inode_readahead_blks-1);
4212 end = b + EXT4_SB(sb)->s_inode_readahead_blks;
4213 num = EXT4_INODES_PER_GROUP(sb);
4214 if (EXT4_HAS_RO_COMPAT_FEATURE(sb,
4215 EXT4_FEATURE_RO_COMPAT_GDT_CSUM))
4216 num -= ext4_itable_unused_count(sb, gdp);
4217 table += num / inodes_per_block;
4221 sb_breadahead(sb, b++);
4225 * There are other valid inodes in the buffer, this inode
4226 * has in-inode xattrs, or we don't have this inode in memory.
4227 * Read the block from disk.
4230 bh->b_end_io = end_buffer_read_sync;
4231 submit_bh(READ_META, bh);
4233 if (!buffer_uptodate(bh)) {
4234 ext4_error(sb, __func__,
4235 "unable to read inode block - inode=%lu, "
4236 "block=%llu", inode->i_ino, block);
4246 int ext4_get_inode_loc(struct inode *inode, struct ext4_iloc *iloc)
4248 /* We have all inode data except xattrs in memory here. */
4249 return __ext4_get_inode_loc(inode, iloc,
4250 !(EXT4_I(inode)->i_state & EXT4_STATE_XATTR));
4253 void ext4_set_inode_flags(struct inode *inode)
4255 unsigned int flags = EXT4_I(inode)->i_flags;
4257 inode->i_flags &= ~(S_SYNC|S_APPEND|S_IMMUTABLE|S_NOATIME|S_DIRSYNC);
4258 if (flags & EXT4_SYNC_FL)
4259 inode->i_flags |= S_SYNC;
4260 if (flags & EXT4_APPEND_FL)
4261 inode->i_flags |= S_APPEND;
4262 if (flags & EXT4_IMMUTABLE_FL)
4263 inode->i_flags |= S_IMMUTABLE;
4264 if (flags & EXT4_NOATIME_FL)
4265 inode->i_flags |= S_NOATIME;
4266 if (flags & EXT4_DIRSYNC_FL)
4267 inode->i_flags |= S_DIRSYNC;
4270 /* Propagate flags from i_flags to EXT4_I(inode)->i_flags */
4271 void ext4_get_inode_flags(struct ext4_inode_info *ei)
4273 unsigned int flags = ei->vfs_inode.i_flags;
4275 ei->i_flags &= ~(EXT4_SYNC_FL|EXT4_APPEND_FL|
4276 EXT4_IMMUTABLE_FL|EXT4_NOATIME_FL|EXT4_DIRSYNC_FL);
4278 ei->i_flags |= EXT4_SYNC_FL;
4279 if (flags & S_APPEND)
4280 ei->i_flags |= EXT4_APPEND_FL;
4281 if (flags & S_IMMUTABLE)
4282 ei->i_flags |= EXT4_IMMUTABLE_FL;
4283 if (flags & S_NOATIME)
4284 ei->i_flags |= EXT4_NOATIME_FL;
4285 if (flags & S_DIRSYNC)
4286 ei->i_flags |= EXT4_DIRSYNC_FL;
4288 static blkcnt_t ext4_inode_blocks(struct ext4_inode *raw_inode,
4289 struct ext4_inode_info *ei)
4292 struct inode *inode = &(ei->vfs_inode);
4293 struct super_block *sb = inode->i_sb;
4295 if (EXT4_HAS_RO_COMPAT_FEATURE(sb,
4296 EXT4_FEATURE_RO_COMPAT_HUGE_FILE)) {
4297 /* we are using combined 48 bit field */
4298 i_blocks = ((u64)le16_to_cpu(raw_inode->i_blocks_high)) << 32 |
4299 le32_to_cpu(raw_inode->i_blocks_lo);
4300 if (ei->i_flags & EXT4_HUGE_FILE_FL) {
4301 /* i_blocks represent file system block size */
4302 return i_blocks << (inode->i_blkbits - 9);
4307 return le32_to_cpu(raw_inode->i_blocks_lo);
4311 struct inode *ext4_iget(struct super_block *sb, unsigned long ino)
4313 struct ext4_iloc iloc;
4314 struct ext4_inode *raw_inode;
4315 struct ext4_inode_info *ei;
4316 struct buffer_head *bh;
4317 struct inode *inode;
4321 inode = iget_locked(sb, ino);
4323 return ERR_PTR(-ENOMEM);
4324 if (!(inode->i_state & I_NEW))
4328 #ifdef CONFIG_EXT4_FS_POSIX_ACL
4329 ei->i_acl = EXT4_ACL_NOT_CACHED;
4330 ei->i_default_acl = EXT4_ACL_NOT_CACHED;
4333 ret = __ext4_get_inode_loc(inode, &iloc, 0);
4337 raw_inode = ext4_raw_inode(&iloc);
4338 inode->i_mode = le16_to_cpu(raw_inode->i_mode);
4339 inode->i_uid = (uid_t)le16_to_cpu(raw_inode->i_uid_low);
4340 inode->i_gid = (gid_t)le16_to_cpu(raw_inode->i_gid_low);
4341 if (!(test_opt(inode->i_sb, NO_UID32))) {
4342 inode->i_uid |= le16_to_cpu(raw_inode->i_uid_high) << 16;
4343 inode->i_gid |= le16_to_cpu(raw_inode->i_gid_high) << 16;
4345 inode->i_nlink = le16_to_cpu(raw_inode->i_links_count);
4348 ei->i_dir_start_lookup = 0;
4349 ei->i_dtime = le32_to_cpu(raw_inode->i_dtime);
4350 /* We now have enough fields to check if the inode was active or not.
4351 * This is needed because nfsd might try to access dead inodes
4352 * the test is that same one that e2fsck uses
4353 * NeilBrown 1999oct15
4355 if (inode->i_nlink == 0) {
4356 if (inode->i_mode == 0 ||
4357 !(EXT4_SB(inode->i_sb)->s_mount_state & EXT4_ORPHAN_FS)) {
4358 /* this inode is deleted */
4363 /* The only unlinked inodes we let through here have
4364 * valid i_mode and are being read by the orphan
4365 * recovery code: that's fine, we're about to complete
4366 * the process of deleting those. */
4368 ei->i_flags = le32_to_cpu(raw_inode->i_flags);
4369 inode->i_blocks = ext4_inode_blocks(raw_inode, ei);
4370 ei->i_file_acl = le32_to_cpu(raw_inode->i_file_acl_lo);
4371 if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_64BIT))
4373 ((__u64)le16_to_cpu(raw_inode->i_file_acl_high)) << 32;
4374 inode->i_size = ext4_isize(raw_inode);
4375 ei->i_disksize = inode->i_size;
4376 inode->i_generation = le32_to_cpu(raw_inode->i_generation);
4377 ei->i_block_group = iloc.block_group;
4378 ei->i_last_alloc_group = ~0;
4380 * NOTE! The in-memory inode i_data array is in little-endian order
4381 * even on big-endian machines: we do NOT byteswap the block numbers!
4383 for (block = 0; block < EXT4_N_BLOCKS; block++)
4384 ei->i_data[block] = raw_inode->i_block[block];
4385 INIT_LIST_HEAD(&ei->i_orphan);
4387 if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE) {
4388 ei->i_extra_isize = le16_to_cpu(raw_inode->i_extra_isize);
4389 if (EXT4_GOOD_OLD_INODE_SIZE + ei->i_extra_isize >
4390 EXT4_INODE_SIZE(inode->i_sb)) {
4395 if (ei->i_extra_isize == 0) {
4396 /* The extra space is currently unused. Use it. */
4397 ei->i_extra_isize = sizeof(struct ext4_inode) -
4398 EXT4_GOOD_OLD_INODE_SIZE;
4400 __le32 *magic = (void *)raw_inode +
4401 EXT4_GOOD_OLD_INODE_SIZE +
4403 if (*magic == cpu_to_le32(EXT4_XATTR_MAGIC))
4404 ei->i_state |= EXT4_STATE_XATTR;
4407 ei->i_extra_isize = 0;
4409 EXT4_INODE_GET_XTIME(i_ctime, inode, raw_inode);
4410 EXT4_INODE_GET_XTIME(i_mtime, inode, raw_inode);
4411 EXT4_INODE_GET_XTIME(i_atime, inode, raw_inode);
4412 EXT4_EINODE_GET_XTIME(i_crtime, ei, raw_inode);
4414 inode->i_version = le32_to_cpu(raw_inode->i_disk_version);
4415 if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE) {
4416 if (EXT4_FITS_IN_INODE(raw_inode, ei, i_version_hi))
4418 (__u64)(le32_to_cpu(raw_inode->i_version_hi)) << 32;
4422 if (ei->i_file_acl &&
4424 (le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block) +
4425 EXT4_SB(sb)->s_gdb_count)) ||
4426 (ei->i_file_acl >= ext4_blocks_count(EXT4_SB(sb)->s_es)))) {
4427 ext4_error(sb, __func__,
4428 "bad extended attribute block %llu in inode #%lu",
4429 ei->i_file_acl, inode->i_ino);
4432 } else if (ei->i_flags & EXT4_EXTENTS_FL) {
4433 if (S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
4434 (S_ISLNK(inode->i_mode) &&
4435 !ext4_inode_is_fast_symlink(inode)))
4436 /* Validate extent which is part of inode */
4437 ret = ext4_ext_check_inode(inode);
4438 } else if (S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
4439 (S_ISLNK(inode->i_mode) &&
4440 !ext4_inode_is_fast_symlink(inode))) {
4441 /* Validate block references which are part of inode */
4442 ret = ext4_check_inode_blockref(inode);
4449 if (S_ISREG(inode->i_mode)) {
4450 inode->i_op = &ext4_file_inode_operations;
4451 inode->i_fop = &ext4_file_operations;
4452 ext4_set_aops(inode);
4453 } else if (S_ISDIR(inode->i_mode)) {
4454 inode->i_op = &ext4_dir_inode_operations;
4455 inode->i_fop = &ext4_dir_operations;
4456 } else if (S_ISLNK(inode->i_mode)) {
4457 if (ext4_inode_is_fast_symlink(inode)) {
4458 inode->i_op = &ext4_fast_symlink_inode_operations;
4459 nd_terminate_link(ei->i_data, inode->i_size,
4460 sizeof(ei->i_data) - 1);
4462 inode->i_op = &ext4_symlink_inode_operations;
4463 ext4_set_aops(inode);
4465 } else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode) ||
4466 S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode)) {
4467 inode->i_op = &ext4_special_inode_operations;
4468 if (raw_inode->i_block[0])
4469 init_special_inode(inode, inode->i_mode,
4470 old_decode_dev(le32_to_cpu(raw_inode->i_block[0])));
4472 init_special_inode(inode, inode->i_mode,
4473 new_decode_dev(le32_to_cpu(raw_inode->i_block[1])));
4477 ext4_error(inode->i_sb, __func__,
4478 "bogus i_mode (%o) for inode=%lu",
4479 inode->i_mode, inode->i_ino);
4483 ext4_set_inode_flags(inode);
4484 unlock_new_inode(inode);
4489 return ERR_PTR(ret);
4492 static int ext4_inode_blocks_set(handle_t *handle,
4493 struct ext4_inode *raw_inode,
4494 struct ext4_inode_info *ei)
4496 struct inode *inode = &(ei->vfs_inode);
4497 u64 i_blocks = inode->i_blocks;
4498 struct super_block *sb = inode->i_sb;
4500 if (i_blocks <= ~0U) {
4502 * i_blocks can be represnted in a 32 bit variable
4503 * as multiple of 512 bytes
4505 raw_inode->i_blocks_lo = cpu_to_le32(i_blocks);
4506 raw_inode->i_blocks_high = 0;
4507 ei->i_flags &= ~EXT4_HUGE_FILE_FL;
4510 if (!EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_HUGE_FILE))
4513 if (i_blocks <= 0xffffffffffffULL) {
4515 * i_blocks can be represented in a 48 bit variable
4516 * as multiple of 512 bytes
4518 raw_inode->i_blocks_lo = cpu_to_le32(i_blocks);
4519 raw_inode->i_blocks_high = cpu_to_le16(i_blocks >> 32);
4520 ei->i_flags &= ~EXT4_HUGE_FILE_FL;
4522 ei->i_flags |= EXT4_HUGE_FILE_FL;
4523 /* i_block is stored in file system block size */
4524 i_blocks = i_blocks >> (inode->i_blkbits - 9);
4525 raw_inode->i_blocks_lo = cpu_to_le32(i_blocks);
4526 raw_inode->i_blocks_high = cpu_to_le16(i_blocks >> 32);
4532 * Post the struct inode info into an on-disk inode location in the
4533 * buffer-cache. This gobbles the caller's reference to the
4534 * buffer_head in the inode location struct.
4536 * The caller must have write access to iloc->bh.
4538 static int ext4_do_update_inode(handle_t *handle,
4539 struct inode *inode,
4540 struct ext4_iloc *iloc)
4542 struct ext4_inode *raw_inode = ext4_raw_inode(iloc);
4543 struct ext4_inode_info *ei = EXT4_I(inode);
4544 struct buffer_head *bh = iloc->bh;
4545 int err = 0, rc, block;
4547 /* For fields not not tracking in the in-memory inode,
4548 * initialise them to zero for new inodes. */
4549 if (ei->i_state & EXT4_STATE_NEW)
4550 memset(raw_inode, 0, EXT4_SB(inode->i_sb)->s_inode_size);
4552 ext4_get_inode_flags(ei);
4553 raw_inode->i_mode = cpu_to_le16(inode->i_mode);
4554 if (!(test_opt(inode->i_sb, NO_UID32))) {
4555 raw_inode->i_uid_low = cpu_to_le16(low_16_bits(inode->i_uid));
4556 raw_inode->i_gid_low = cpu_to_le16(low_16_bits(inode->i_gid));
4558 * Fix up interoperability with old kernels. Otherwise, old inodes get
4559 * re-used with the upper 16 bits of the uid/gid intact
4562 raw_inode->i_uid_high =
4563 cpu_to_le16(high_16_bits(inode->i_uid));
4564 raw_inode->i_gid_high =
4565 cpu_to_le16(high_16_bits(inode->i_gid));
4567 raw_inode->i_uid_high = 0;
4568 raw_inode->i_gid_high = 0;
4571 raw_inode->i_uid_low =
4572 cpu_to_le16(fs_high2lowuid(inode->i_uid));
4573 raw_inode->i_gid_low =
4574 cpu_to_le16(fs_high2lowgid(inode->i_gid));
4575 raw_inode->i_uid_high = 0;
4576 raw_inode->i_gid_high = 0;
4578 raw_inode->i_links_count = cpu_to_le16(inode->i_nlink);
4580 EXT4_INODE_SET_XTIME(i_ctime, inode, raw_inode);
4581 EXT4_INODE_SET_XTIME(i_mtime, inode, raw_inode);
4582 EXT4_INODE_SET_XTIME(i_atime, inode, raw_inode);
4583 EXT4_EINODE_SET_XTIME(i_crtime, ei, raw_inode);
4585 if (ext4_inode_blocks_set(handle, raw_inode, ei))
4587 raw_inode->i_dtime = cpu_to_le32(ei->i_dtime);
4588 /* clear the migrate flag in the raw_inode */
4589 raw_inode->i_flags = cpu_to_le32(ei->i_flags & ~EXT4_EXT_MIGRATE);
4590 if (EXT4_SB(inode->i_sb)->s_es->s_creator_os !=
4591 cpu_to_le32(EXT4_OS_HURD))
4592 raw_inode->i_file_acl_high =
4593 cpu_to_le16(ei->i_file_acl >> 32);
4594 raw_inode->i_file_acl_lo = cpu_to_le32(ei->i_file_acl);
4595 ext4_isize_set(raw_inode, ei->i_disksize);
4596 if (ei->i_disksize > 0x7fffffffULL) {
4597 struct super_block *sb = inode->i_sb;
4598 if (!EXT4_HAS_RO_COMPAT_FEATURE(sb,
4599 EXT4_FEATURE_RO_COMPAT_LARGE_FILE) ||
4600 EXT4_SB(sb)->s_es->s_rev_level ==
4601 cpu_to_le32(EXT4_GOOD_OLD_REV)) {
4602 /* If this is the first large file
4603 * created, add a flag to the superblock.
4605 err = ext4_journal_get_write_access(handle,
4606 EXT4_SB(sb)->s_sbh);
4609 ext4_update_dynamic_rev(sb);
4610 EXT4_SET_RO_COMPAT_FEATURE(sb,
4611 EXT4_FEATURE_RO_COMPAT_LARGE_FILE);
4613 ext4_handle_sync(handle);
4614 err = ext4_handle_dirty_metadata(handle, inode,
4615 EXT4_SB(sb)->s_sbh);
4618 raw_inode->i_generation = cpu_to_le32(inode->i_generation);
4619 if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode)) {
4620 if (old_valid_dev(inode->i_rdev)) {
4621 raw_inode->i_block[0] =
4622 cpu_to_le32(old_encode_dev(inode->i_rdev));
4623 raw_inode->i_block[1] = 0;
4625 raw_inode->i_block[0] = 0;
4626 raw_inode->i_block[1] =
4627 cpu_to_le32(new_encode_dev(inode->i_rdev));
4628 raw_inode->i_block[2] = 0;
4630 } else for (block = 0; block < EXT4_N_BLOCKS; block++)
4631 raw_inode->i_block[block] = ei->i_data[block];
4633 raw_inode->i_disk_version = cpu_to_le32(inode->i_version);
4634 if (ei->i_extra_isize) {
4635 if (EXT4_FITS_IN_INODE(raw_inode, ei, i_version_hi))
4636 raw_inode->i_version_hi =
4637 cpu_to_le32(inode->i_version >> 32);
4638 raw_inode->i_extra_isize = cpu_to_le16(ei->i_extra_isize);
4641 BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
4642 rc = ext4_handle_dirty_metadata(handle, inode, bh);
4645 ei->i_state &= ~EXT4_STATE_NEW;
4649 ext4_std_error(inode->i_sb, err);
4654 * ext4_write_inode()
4656 * We are called from a few places:
4658 * - Within generic_file_write() for O_SYNC files.
4659 * Here, there will be no transaction running. We wait for any running
4660 * trasnaction to commit.
4662 * - Within sys_sync(), kupdate and such.
4663 * We wait on commit, if tol to.
4665 * - Within prune_icache() (PF_MEMALLOC == true)
4666 * Here we simply return. We can't afford to block kswapd on the
4669 * In all cases it is actually safe for us to return without doing anything,
4670 * because the inode has been copied into a raw inode buffer in
4671 * ext4_mark_inode_dirty(). This is a correctness thing for O_SYNC and for
4674 * Note that we are absolutely dependent upon all inode dirtiers doing the
4675 * right thing: they *must* call mark_inode_dirty() after dirtying info in
4676 * which we are interested.
4678 * It would be a bug for them to not do this. The code:
4680 * mark_inode_dirty(inode)
4682 * inode->i_size = expr;
4684 * is in error because a kswapd-driven write_inode() could occur while
4685 * `stuff()' is running, and the new i_size will be lost. Plus the inode
4686 * will no longer be on the superblock's dirty inode list.
4688 int ext4_write_inode(struct inode *inode, int wait)
4690 if (current->flags & PF_MEMALLOC)
4693 if (ext4_journal_current_handle()) {
4694 jbd_debug(1, "called recursively, non-PF_MEMALLOC!\n");
4702 return ext4_force_commit(inode->i_sb);
4705 int __ext4_write_dirty_metadata(struct inode *inode, struct buffer_head *bh)
4709 mark_buffer_dirty(bh);
4710 if (inode && inode_needs_sync(inode)) {
4711 sync_dirty_buffer(bh);
4712 if (buffer_req(bh) && !buffer_uptodate(bh)) {
4713 ext4_error(inode->i_sb, __func__,
4714 "IO error syncing inode, "
4715 "inode=%lu, block=%llu",
4717 (unsigned long long)bh->b_blocknr);
4727 * Called from notify_change.
4729 * We want to trap VFS attempts to truncate the file as soon as
4730 * possible. In particular, we want to make sure that when the VFS
4731 * shrinks i_size, we put the inode on the orphan list and modify
4732 * i_disksize immediately, so that during the subsequent flushing of
4733 * dirty pages and freeing of disk blocks, we can guarantee that any
4734 * commit will leave the blocks being flushed in an unused state on
4735 * disk. (On recovery, the inode will get truncated and the blocks will
4736 * be freed, so we have a strong guarantee that no future commit will
4737 * leave these blocks visible to the user.)
4739 * Another thing we have to assure is that if we are in ordered mode
4740 * and inode is still attached to the committing transaction, we must
4741 * we start writeout of all the dirty pages which are being truncated.
4742 * This way we are sure that all the data written in the previous
4743 * transaction are already on disk (truncate waits for pages under
4746 * Called with inode->i_mutex down.
4748 int ext4_setattr(struct dentry *dentry, struct iattr *attr)
4750 struct inode *inode = dentry->d_inode;
4752 const unsigned int ia_valid = attr->ia_valid;
4754 error = inode_change_ok(inode, attr);
4758 if ((ia_valid & ATTR_UID && attr->ia_uid != inode->i_uid) ||
4759 (ia_valid & ATTR_GID && attr->ia_gid != inode->i_gid)) {
4762 /* (user+group)*(old+new) structure, inode write (sb,
4763 * inode block, ? - but truncate inode update has it) */
4764 handle = ext4_journal_start(inode, 2*(EXT4_QUOTA_INIT_BLOCKS(inode->i_sb)+
4765 EXT4_QUOTA_DEL_BLOCKS(inode->i_sb))+3);
4766 if (IS_ERR(handle)) {
4767 error = PTR_ERR(handle);
4770 error = vfs_dq_transfer(inode, attr) ? -EDQUOT : 0;
4772 ext4_journal_stop(handle);
4775 /* Update corresponding info in inode so that everything is in
4776 * one transaction */
4777 if (attr->ia_valid & ATTR_UID)
4778 inode->i_uid = attr->ia_uid;
4779 if (attr->ia_valid & ATTR_GID)
4780 inode->i_gid = attr->ia_gid;
4781 error = ext4_mark_inode_dirty(handle, inode);
4782 ext4_journal_stop(handle);
4785 if (attr->ia_valid & ATTR_SIZE) {
4786 if (!(EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL)) {
4787 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
4789 if (attr->ia_size > sbi->s_bitmap_maxbytes) {
4796 if (S_ISREG(inode->i_mode) &&
4797 attr->ia_valid & ATTR_SIZE && attr->ia_size < inode->i_size) {
4800 handle = ext4_journal_start(inode, 3);
4801 if (IS_ERR(handle)) {
4802 error = PTR_ERR(handle);
4806 error = ext4_orphan_add(handle, inode);
4807 EXT4_I(inode)->i_disksize = attr->ia_size;
4808 rc = ext4_mark_inode_dirty(handle, inode);
4811 ext4_journal_stop(handle);
4813 if (ext4_should_order_data(inode)) {
4814 error = ext4_begin_ordered_truncate(inode,
4817 /* Do as much error cleanup as possible */
4818 handle = ext4_journal_start(inode, 3);
4819 if (IS_ERR(handle)) {
4820 ext4_orphan_del(NULL, inode);
4823 ext4_orphan_del(handle, inode);
4824 ext4_journal_stop(handle);
4830 rc = inode_setattr(inode, attr);
4832 /* If inode_setattr's call to ext4_truncate failed to get a
4833 * transaction handle at all, we need to clean up the in-core
4834 * orphan list manually. */
4836 ext4_orphan_del(NULL, inode);
4838 if (!rc && (ia_valid & ATTR_MODE))
4839 rc = ext4_acl_chmod(inode);
4842 ext4_std_error(inode->i_sb, error);
4848 int ext4_getattr(struct vfsmount *mnt, struct dentry *dentry,
4851 struct inode *inode;
4852 unsigned long delalloc_blocks;
4854 inode = dentry->d_inode;
4855 generic_fillattr(inode, stat);
4858 * We can't update i_blocks if the block allocation is delayed
4859 * otherwise in the case of system crash before the real block
4860 * allocation is done, we will have i_blocks inconsistent with
4861 * on-disk file blocks.
4862 * We always keep i_blocks updated together with real
4863 * allocation. But to not confuse with user, stat
4864 * will return the blocks that include the delayed allocation
4865 * blocks for this file.
4867 spin_lock(&EXT4_I(inode)->i_block_reservation_lock);
4868 delalloc_blocks = EXT4_I(inode)->i_reserved_data_blocks;
4869 spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
4871 stat->blocks += (delalloc_blocks << inode->i_sb->s_blocksize_bits)>>9;
4875 static int ext4_indirect_trans_blocks(struct inode *inode, int nrblocks,
4880 /* if nrblocks are contiguous */
4883 * With N contiguous data blocks, it need at most
4884 * N/EXT4_ADDR_PER_BLOCK(inode->i_sb) indirect blocks
4885 * 2 dindirect blocks
4888 indirects = nrblocks / EXT4_ADDR_PER_BLOCK(inode->i_sb);
4889 return indirects + 3;
4892 * if nrblocks are not contiguous, worse case, each block touch
4893 * a indirect block, and each indirect block touch a double indirect
4894 * block, plus a triple indirect block
4896 indirects = nrblocks * 2 + 1;
4900 static int ext4_index_trans_blocks(struct inode *inode, int nrblocks, int chunk)
4902 if (!(EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL))
4903 return ext4_indirect_trans_blocks(inode, nrblocks, chunk);
4904 return ext4_ext_index_trans_blocks(inode, nrblocks, chunk);
4908 * Account for index blocks, block groups bitmaps and block group
4909 * descriptor blocks if modify datablocks and index blocks
4910 * worse case, the indexs blocks spread over different block groups
4912 * If datablocks are discontiguous, they are possible to spread over
4913 * different block groups too. If they are contiugous, with flexbg,
4914 * they could still across block group boundary.
4916 * Also account for superblock, inode, quota and xattr blocks
4918 int ext4_meta_trans_blocks(struct inode *inode, int nrblocks, int chunk)
4920 int groups, gdpblocks;
4925 * How many index blocks need to touch to modify nrblocks?
4926 * The "Chunk" flag indicating whether the nrblocks is
4927 * physically contiguous on disk
4929 * For Direct IO and fallocate, they calls get_block to allocate
4930 * one single extent at a time, so they could set the "Chunk" flag
4932 idxblocks = ext4_index_trans_blocks(inode, nrblocks, chunk);
4937 * Now let's see how many group bitmaps and group descriptors need
4947 if (groups > EXT4_SB(inode->i_sb)->s_groups_count)
4948 groups = EXT4_SB(inode->i_sb)->s_groups_count;
4949 if (groups > EXT4_SB(inode->i_sb)->s_gdb_count)
4950 gdpblocks = EXT4_SB(inode->i_sb)->s_gdb_count;
4952 /* bitmaps and block group descriptor blocks */
4953 ret += groups + gdpblocks;
4955 /* Blocks for super block, inode, quota and xattr blocks */
4956 ret += EXT4_META_TRANS_BLOCKS(inode->i_sb);
4962 * Calulate the total number of credits to reserve to fit
4963 * the modification of a single pages into a single transaction,
4964 * which may include multiple chunks of block allocations.
4966 * This could be called via ext4_write_begin()
4968 * We need to consider the worse case, when
4969 * one new block per extent.
4971 int ext4_writepage_trans_blocks(struct inode *inode)
4973 int bpp = ext4_journal_blocks_per_page(inode);
4976 ret = ext4_meta_trans_blocks(inode, bpp, 0);
4978 /* Account for data blocks for journalled mode */
4979 if (ext4_should_journal_data(inode))
4985 * Calculate the journal credits for a chunk of data modification.
4987 * This is called from DIO, fallocate or whoever calling
4988 * ext4_get_blocks_wrap() to map/allocate a chunk of contigous disk blocks.
4990 * journal buffers for data blocks are not included here, as DIO
4991 * and fallocate do no need to journal data buffers.
4993 int ext4_chunk_trans_blocks(struct inode *inode, int nrblocks)
4995 return ext4_meta_trans_blocks(inode, nrblocks, 1);
4999 * The caller must have previously called ext4_reserve_inode_write().
5000 * Give this, we know that the caller already has write access to iloc->bh.
5002 int ext4_mark_iloc_dirty(handle_t *handle,
5003 struct inode *inode, struct ext4_iloc *iloc)
5007 if (test_opt(inode->i_sb, I_VERSION))
5008 inode_inc_iversion(inode);
5010 /* the do_update_inode consumes one bh->b_count */
5013 /* ext4_do_update_inode() does jbd2_journal_dirty_metadata */
5014 err = ext4_do_update_inode(handle, inode, iloc);
5020 * On success, We end up with an outstanding reference count against
5021 * iloc->bh. This _must_ be cleaned up later.
5025 ext4_reserve_inode_write(handle_t *handle, struct inode *inode,
5026 struct ext4_iloc *iloc)
5030 err = ext4_get_inode_loc(inode, iloc);
5032 BUFFER_TRACE(iloc->bh, "get_write_access");
5033 err = ext4_journal_get_write_access(handle, iloc->bh);
5039 ext4_std_error(inode->i_sb, err);
5044 * Expand an inode by new_extra_isize bytes.
5045 * Returns 0 on success or negative error number on failure.
5047 static int ext4_expand_extra_isize(struct inode *inode,
5048 unsigned int new_extra_isize,
5049 struct ext4_iloc iloc,
5052 struct ext4_inode *raw_inode;
5053 struct ext4_xattr_ibody_header *header;
5054 struct ext4_xattr_entry *entry;
5056 if (EXT4_I(inode)->i_extra_isize >= new_extra_isize)
5059 raw_inode = ext4_raw_inode(&iloc);
5061 header = IHDR(inode, raw_inode);
5062 entry = IFIRST(header);
5064 /* No extended attributes present */
5065 if (!(EXT4_I(inode)->i_state & EXT4_STATE_XATTR) ||
5066 header->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC)) {
5067 memset((void *)raw_inode + EXT4_GOOD_OLD_INODE_SIZE, 0,
5069 EXT4_I(inode)->i_extra_isize = new_extra_isize;
5073 /* try to expand with EAs present */
5074 return ext4_expand_extra_isize_ea(inode, new_extra_isize,
5079 * What we do here is to mark the in-core inode as clean with respect to inode
5080 * dirtiness (it may still be data-dirty).
5081 * This means that the in-core inode may be reaped by prune_icache
5082 * without having to perform any I/O. This is a very good thing,
5083 * because *any* task may call prune_icache - even ones which
5084 * have a transaction open against a different journal.
5086 * Is this cheating? Not really. Sure, we haven't written the
5087 * inode out, but prune_icache isn't a user-visible syncing function.
5088 * Whenever the user wants stuff synced (sys_sync, sys_msync, sys_fsync)
5089 * we start and wait on commits.
5091 * Is this efficient/effective? Well, we're being nice to the system
5092 * by cleaning up our inodes proactively so they can be reaped
5093 * without I/O. But we are potentially leaving up to five seconds'
5094 * worth of inodes floating about which prune_icache wants us to
5095 * write out. One way to fix that would be to get prune_icache()
5096 * to do a write_super() to free up some memory. It has the desired
5099 int ext4_mark_inode_dirty(handle_t *handle, struct inode *inode)
5101 struct ext4_iloc iloc;
5102 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
5103 static unsigned int mnt_count;
5107 err = ext4_reserve_inode_write(handle, inode, &iloc);
5108 if (ext4_handle_valid(handle) &&
5109 EXT4_I(inode)->i_extra_isize < sbi->s_want_extra_isize &&
5110 !(EXT4_I(inode)->i_state & EXT4_STATE_NO_EXPAND)) {
5112 * We need extra buffer credits since we may write into EA block
5113 * with this same handle. If journal_extend fails, then it will
5114 * only result in a minor loss of functionality for that inode.
5115 * If this is felt to be critical, then e2fsck should be run to
5116 * force a large enough s_min_extra_isize.
5118 if ((jbd2_journal_extend(handle,
5119 EXT4_DATA_TRANS_BLOCKS(inode->i_sb))) == 0) {
5120 ret = ext4_expand_extra_isize(inode,
5121 sbi->s_want_extra_isize,
5124 EXT4_I(inode)->i_state |= EXT4_STATE_NO_EXPAND;
5126 le16_to_cpu(sbi->s_es->s_mnt_count)) {
5127 ext4_warning(inode->i_sb, __func__,
5128 "Unable to expand inode %lu. Delete"
5129 " some EAs or run e2fsck.",
5132 le16_to_cpu(sbi->s_es->s_mnt_count);
5138 err = ext4_mark_iloc_dirty(handle, inode, &iloc);
5143 * ext4_dirty_inode() is called from __mark_inode_dirty()
5145 * We're really interested in the case where a file is being extended.
5146 * i_size has been changed by generic_commit_write() and we thus need
5147 * to include the updated inode in the current transaction.
5149 * Also, vfs_dq_alloc_block() will always dirty the inode when blocks
5150 * are allocated to the file.
5152 * If the inode is marked synchronous, we don't honour that here - doing
5153 * so would cause a commit on atime updates, which we don't bother doing.
5154 * We handle synchronous inodes at the highest possible level.
5156 void ext4_dirty_inode(struct inode *inode)
5158 handle_t *current_handle = ext4_journal_current_handle();
5161 if (!ext4_handle_valid(current_handle)) {
5162 ext4_mark_inode_dirty(current_handle, inode);
5166 handle = ext4_journal_start(inode, 2);
5169 if (current_handle &&
5170 current_handle->h_transaction != handle->h_transaction) {
5171 /* This task has a transaction open against a different fs */
5172 printk(KERN_EMERG "%s: transactions do not match!\n",
5175 jbd_debug(5, "marking dirty. outer handle=%p\n",
5177 ext4_mark_inode_dirty(handle, inode);
5179 ext4_journal_stop(handle);
5186 * Bind an inode's backing buffer_head into this transaction, to prevent
5187 * it from being flushed to disk early. Unlike
5188 * ext4_reserve_inode_write, this leaves behind no bh reference and
5189 * returns no iloc structure, so the caller needs to repeat the iloc
5190 * lookup to mark the inode dirty later.
5192 static int ext4_pin_inode(handle_t *handle, struct inode *inode)
5194 struct ext4_iloc iloc;
5198 err = ext4_get_inode_loc(inode, &iloc);
5200 BUFFER_TRACE(iloc.bh, "get_write_access");
5201 err = jbd2_journal_get_write_access(handle, iloc.bh);
5203 err = ext4_handle_dirty_metadata(handle,
5209 ext4_std_error(inode->i_sb, err);
5214 int ext4_change_inode_journal_flag(struct inode *inode, int val)
5221 * We have to be very careful here: changing a data block's
5222 * journaling status dynamically is dangerous. If we write a
5223 * data block to the journal, change the status and then delete
5224 * that block, we risk forgetting to revoke the old log record
5225 * from the journal and so a subsequent replay can corrupt data.
5226 * So, first we make sure that the journal is empty and that
5227 * nobody is changing anything.
5230 journal = EXT4_JOURNAL(inode);
5233 if (is_journal_aborted(journal))
5236 jbd2_journal_lock_updates(journal);
5237 jbd2_journal_flush(journal);
5240 * OK, there are no updates running now, and all cached data is
5241 * synced to disk. We are now in a completely consistent state
5242 * which doesn't have anything in the journal, and we know that
5243 * no filesystem updates are running, so it is safe to modify
5244 * the inode's in-core data-journaling state flag now.
5248 EXT4_I(inode)->i_flags |= EXT4_JOURNAL_DATA_FL;
5250 EXT4_I(inode)->i_flags &= ~EXT4_JOURNAL_DATA_FL;
5251 ext4_set_aops(inode);
5253 jbd2_journal_unlock_updates(journal);
5255 /* Finally we can mark the inode as dirty. */
5257 handle = ext4_journal_start(inode, 1);
5259 return PTR_ERR(handle);
5261 err = ext4_mark_inode_dirty(handle, inode);
5262 ext4_handle_sync(handle);
5263 ext4_journal_stop(handle);
5264 ext4_std_error(inode->i_sb, err);
5269 static int ext4_bh_unmapped(handle_t *handle, struct buffer_head *bh)
5271 return !buffer_mapped(bh);
5274 int ext4_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
5276 struct page *page = vmf->page;
5281 struct file *file = vma->vm_file;
5282 struct inode *inode = file->f_path.dentry->d_inode;
5283 struct address_space *mapping = inode->i_mapping;
5286 * Get i_alloc_sem to stop truncates messing with the inode. We cannot
5287 * get i_mutex because we are already holding mmap_sem.
5289 down_read(&inode->i_alloc_sem);
5290 size = i_size_read(inode);
5291 if (page->mapping != mapping || size <= page_offset(page)
5292 || !PageUptodate(page)) {
5293 /* page got truncated from under us? */
5297 if (PageMappedToDisk(page))
5300 if (page->index == size >> PAGE_CACHE_SHIFT)
5301 len = size & ~PAGE_CACHE_MASK;
5303 len = PAGE_CACHE_SIZE;
5305 if (page_has_buffers(page)) {
5306 /* return if we have all the buffers mapped */
5307 if (!walk_page_buffers(NULL, page_buffers(page), 0, len, NULL,
5312 * OK, we need to fill the hole... Do write_begin write_end
5313 * to do block allocation/reservation.We are not holding
5314 * inode.i__mutex here. That allow * parallel write_begin,
5315 * write_end call. lock_page prevent this from happening
5316 * on the same page though
5318 ret = mapping->a_ops->write_begin(file, mapping, page_offset(page),
5319 len, AOP_FLAG_UNINTERRUPTIBLE, &page, &fsdata);
5322 ret = mapping->a_ops->write_end(file, mapping, page_offset(page),
5323 len, len, page, fsdata);
5329 ret = VM_FAULT_SIGBUS;
5330 up_read(&inode->i_alloc_sem);