2 * linux/fs/ext4/inode.c
4 * Copyright (C) 1992, 1993, 1994, 1995
5 * Remy Card (card@masi.ibp.fr)
6 * Laboratoire MASI - Institut Blaise Pascal
7 * Universite Pierre et Marie Curie (Paris VI)
11 * linux/fs/minix/inode.c
13 * Copyright (C) 1991, 1992 Linus Torvalds
15 * Goal-directed block allocation by Stephen Tweedie
16 * (sct@redhat.com), 1993, 1998
17 * Big-endian to little-endian byte-swapping/bitmaps by
18 * David S. Miller (davem@caip.rutgers.edu), 1995
19 * 64-bit file support on 64-bit platforms by Jakub Jelinek
20 * (jj@sunsite.ms.mff.cuni.cz)
22 * Assorted race fixes, rewrite of ext4_get_block() by Al Viro, 2000
25 #include <linux/module.h>
27 #include <linux/time.h>
28 #include <linux/jbd2.h>
29 #include <linux/highuid.h>
30 #include <linux/pagemap.h>
31 #include <linux/quotaops.h>
32 #include <linux/string.h>
33 #include <linux/buffer_head.h>
34 #include <linux/writeback.h>
35 #include <linux/pagevec.h>
36 #include <linux/mpage.h>
37 #include <linux/namei.h>
38 #include <linux/uio.h>
39 #include <linux/bio.h>
40 #include <linux/workqueue.h>
41 #include <linux/kernel.h>
42 #include <linux/slab.h>
44 #include "ext4_jbd2.h"
47 #include "ext4_extents.h"
49 #include <trace/events/ext4.h>
51 #define MPAGE_DA_EXTENT_TAIL 0x01
53 static inline int ext4_begin_ordered_truncate(struct inode
*inode
,
56 return jbd2_journal_begin_ordered_truncate(
57 EXT4_SB(inode
->i_sb
)->s_journal
,
58 &EXT4_I(inode
)->jinode
,
62 static void ext4_invalidatepage(struct page
*page
, unsigned long offset
);
63 static int noalloc_get_block_write(struct inode
*inode
, sector_t iblock
,
64 struct buffer_head
*bh_result
, int create
);
65 static int ext4_set_bh_endio(struct buffer_head
*bh
, struct inode
*inode
);
66 static void ext4_end_io_buffer_write(struct buffer_head
*bh
, int uptodate
);
67 static int __ext4_journalled_writepage(struct page
*page
, unsigned int len
);
68 static int ext4_bh_delay_or_unwritten(handle_t
*handle
, struct buffer_head
*bh
);
71 * Test whether an inode is a fast symlink.
73 static int ext4_inode_is_fast_symlink(struct inode
*inode
)
75 int ea_blocks
= EXT4_I(inode
)->i_file_acl
?
76 (inode
->i_sb
->s_blocksize
>> 9) : 0;
78 return (S_ISLNK(inode
->i_mode
) && inode
->i_blocks
- ea_blocks
== 0);
82 * Work out how many blocks we need to proceed with the next chunk of a
83 * truncate transaction.
85 static unsigned long blocks_for_truncate(struct inode
*inode
)
89 needed
= inode
->i_blocks
>> (inode
->i_sb
->s_blocksize_bits
- 9);
91 /* Give ourselves just enough room to cope with inodes in which
92 * i_blocks is corrupt: we've seen disk corruptions in the past
93 * which resulted in random data in an inode which looked enough
94 * like a regular file for ext4 to try to delete it. Things
95 * will go a bit crazy if that happens, but at least we should
96 * try not to panic the whole kernel. */
100 /* But we need to bound the transaction so we don't overflow the
102 if (needed
> EXT4_MAX_TRANS_DATA
)
103 needed
= EXT4_MAX_TRANS_DATA
;
105 return EXT4_DATA_TRANS_BLOCKS(inode
->i_sb
) + needed
;
109 * Truncate transactions can be complex and absolutely huge. So we need to
110 * be able to restart the transaction at a conventient checkpoint to make
111 * sure we don't overflow the journal.
113 * start_transaction gets us a new handle for a truncate transaction,
114 * and extend_transaction tries to extend the existing one a bit. If
115 * extend fails, we need to propagate the failure up and restart the
116 * transaction in the top-level truncate loop. --sct
118 static handle_t
*start_transaction(struct inode
*inode
)
122 result
= ext4_journal_start(inode
, blocks_for_truncate(inode
));
126 ext4_std_error(inode
->i_sb
, PTR_ERR(result
));
131 * Try to extend this transaction for the purposes of truncation.
133 * Returns 0 if we managed to create more room. If we can't create more
134 * room, and the transaction must be restarted we return 1.
136 static int try_to_extend_transaction(handle_t
*handle
, struct inode
*inode
)
138 if (!ext4_handle_valid(handle
))
140 if (ext4_handle_has_enough_credits(handle
, EXT4_RESERVE_TRANS_BLOCKS
+1))
142 if (!ext4_journal_extend(handle
, blocks_for_truncate(inode
)))
148 * Restart the transaction associated with *handle. This does a commit,
149 * so before we call here everything must be consistently dirtied against
152 int ext4_truncate_restart_trans(handle_t
*handle
, struct inode
*inode
,
158 * Drop i_data_sem to avoid deadlock with ext4_map_blocks. At this
159 * moment, get_block can be called only for blocks inside i_size since
160 * page cache has been already dropped and writes are blocked by
161 * i_mutex. So we can safely drop the i_data_sem here.
163 BUG_ON(EXT4_JOURNAL(inode
) == NULL
);
164 jbd_debug(2, "restarting handle %p\n", handle
);
165 up_write(&EXT4_I(inode
)->i_data_sem
);
166 ret
= ext4_journal_restart(handle
, blocks_for_truncate(inode
));
167 down_write(&EXT4_I(inode
)->i_data_sem
);
168 ext4_discard_preallocations(inode
);
174 * Called at the last iput() if i_nlink is zero.
176 void ext4_evict_inode(struct inode
*inode
)
181 if (inode
->i_nlink
) {
182 truncate_inode_pages(&inode
->i_data
, 0);
186 if (!is_bad_inode(inode
))
187 dquot_initialize(inode
);
189 if (ext4_should_order_data(inode
))
190 ext4_begin_ordered_truncate(inode
, 0);
191 truncate_inode_pages(&inode
->i_data
, 0);
193 if (is_bad_inode(inode
))
196 handle
= ext4_journal_start(inode
, blocks_for_truncate(inode
)+3);
197 if (IS_ERR(handle
)) {
198 ext4_std_error(inode
->i_sb
, PTR_ERR(handle
));
200 * If we're going to skip the normal cleanup, we still need to
201 * make sure that the in-core orphan linked list is properly
204 ext4_orphan_del(NULL
, inode
);
209 ext4_handle_sync(handle
);
211 err
= ext4_mark_inode_dirty(handle
, inode
);
213 ext4_warning(inode
->i_sb
,
214 "couldn't mark inode dirty (err %d)", err
);
218 ext4_truncate(inode
);
221 * ext4_ext_truncate() doesn't reserve any slop when it
222 * restarts journal transactions; therefore there may not be
223 * enough credits left in the handle to remove the inode from
224 * the orphan list and set the dtime field.
226 if (!ext4_handle_has_enough_credits(handle
, 3)) {
227 err
= ext4_journal_extend(handle
, 3);
229 err
= ext4_journal_restart(handle
, 3);
231 ext4_warning(inode
->i_sb
,
232 "couldn't extend journal (err %d)", err
);
234 ext4_journal_stop(handle
);
235 ext4_orphan_del(NULL
, inode
);
241 * Kill off the orphan record which ext4_truncate created.
242 * AKPM: I think this can be inside the above `if'.
243 * Note that ext4_orphan_del() has to be able to cope with the
244 * deletion of a non-existent orphan - this is because we don't
245 * know if ext4_truncate() actually created an orphan record.
246 * (Well, we could do this if we need to, but heck - it works)
248 ext4_orphan_del(handle
, inode
);
249 EXT4_I(inode
)->i_dtime
= get_seconds();
252 * One subtle ordering requirement: if anything has gone wrong
253 * (transaction abort, IO errors, whatever), then we can still
254 * do these next steps (the fs will already have been marked as
255 * having errors), but we can't free the inode if the mark_dirty
258 if (ext4_mark_inode_dirty(handle
, inode
))
259 /* If that failed, just do the required in-core inode clear. */
260 ext4_clear_inode(inode
);
262 ext4_free_inode(handle
, inode
);
263 ext4_journal_stop(handle
);
266 ext4_clear_inode(inode
); /* We must guarantee clearing of inode... */
272 struct buffer_head
*bh
;
275 static inline void add_chain(Indirect
*p
, struct buffer_head
*bh
, __le32
*v
)
277 p
->key
= *(p
->p
= v
);
282 * ext4_block_to_path - parse the block number into array of offsets
283 * @inode: inode in question (we are only interested in its superblock)
284 * @i_block: block number to be parsed
285 * @offsets: array to store the offsets in
286 * @boundary: set this non-zero if the referred-to block is likely to be
287 * followed (on disk) by an indirect block.
289 * To store the locations of file's data ext4 uses a data structure common
290 * for UNIX filesystems - tree of pointers anchored in the inode, with
291 * data blocks at leaves and indirect blocks in intermediate nodes.
292 * This function translates the block number into path in that tree -
293 * return value is the path length and @offsets[n] is the offset of
294 * pointer to (n+1)th node in the nth one. If @block is out of range
295 * (negative or too large) warning is printed and zero returned.
297 * Note: function doesn't find node addresses, so no IO is needed. All
298 * we need to know is the capacity of indirect blocks (taken from the
303 * Portability note: the last comparison (check that we fit into triple
304 * indirect block) is spelled differently, because otherwise on an
305 * architecture with 32-bit longs and 8Kb pages we might get into trouble
306 * if our filesystem had 8Kb blocks. We might use long long, but that would
307 * kill us on x86. Oh, well, at least the sign propagation does not matter -
308 * i_block would have to be negative in the very beginning, so we would not
312 static int ext4_block_to_path(struct inode
*inode
,
314 ext4_lblk_t offsets
[4], int *boundary
)
316 int ptrs
= EXT4_ADDR_PER_BLOCK(inode
->i_sb
);
317 int ptrs_bits
= EXT4_ADDR_PER_BLOCK_BITS(inode
->i_sb
);
318 const long direct_blocks
= EXT4_NDIR_BLOCKS
,
319 indirect_blocks
= ptrs
,
320 double_blocks
= (1 << (ptrs_bits
* 2));
324 if (i_block
< direct_blocks
) {
325 offsets
[n
++] = i_block
;
326 final
= direct_blocks
;
327 } else if ((i_block
-= direct_blocks
) < indirect_blocks
) {
328 offsets
[n
++] = EXT4_IND_BLOCK
;
329 offsets
[n
++] = i_block
;
331 } else if ((i_block
-= indirect_blocks
) < double_blocks
) {
332 offsets
[n
++] = EXT4_DIND_BLOCK
;
333 offsets
[n
++] = i_block
>> ptrs_bits
;
334 offsets
[n
++] = i_block
& (ptrs
- 1);
336 } else if (((i_block
-= double_blocks
) >> (ptrs_bits
* 2)) < ptrs
) {
337 offsets
[n
++] = EXT4_TIND_BLOCK
;
338 offsets
[n
++] = i_block
>> (ptrs_bits
* 2);
339 offsets
[n
++] = (i_block
>> ptrs_bits
) & (ptrs
- 1);
340 offsets
[n
++] = i_block
& (ptrs
- 1);
343 ext4_warning(inode
->i_sb
, "block %lu > max in inode %lu",
344 i_block
+ direct_blocks
+
345 indirect_blocks
+ double_blocks
, inode
->i_ino
);
348 *boundary
= final
- 1 - (i_block
& (ptrs
- 1));
352 static int __ext4_check_blockref(const char *function
, unsigned int line
,
354 __le32
*p
, unsigned int max
)
356 struct ext4_super_block
*es
= EXT4_SB(inode
->i_sb
)->s_es
;
360 while (bref
< p
+max
) {
361 blk
= le32_to_cpu(*bref
++);
363 unlikely(!ext4_data_block_valid(EXT4_SB(inode
->i_sb
),
365 es
->s_last_error_block
= cpu_to_le64(blk
);
366 ext4_error_inode(inode
, function
, line
, blk
,
375 #define ext4_check_indirect_blockref(inode, bh) \
376 __ext4_check_blockref(__func__, __LINE__, inode, \
377 (__le32 *)(bh)->b_data, \
378 EXT4_ADDR_PER_BLOCK((inode)->i_sb))
380 #define ext4_check_inode_blockref(inode) \
381 __ext4_check_blockref(__func__, __LINE__, inode, \
382 EXT4_I(inode)->i_data, \
386 * ext4_get_branch - read the chain of indirect blocks leading to data
387 * @inode: inode in question
388 * @depth: depth of the chain (1 - direct pointer, etc.)
389 * @offsets: offsets of pointers in inode/indirect blocks
390 * @chain: place to store the result
391 * @err: here we store the error value
393 * Function fills the array of triples <key, p, bh> and returns %NULL
394 * if everything went OK or the pointer to the last filled triple
395 * (incomplete one) otherwise. Upon the return chain[i].key contains
396 * the number of (i+1)-th block in the chain (as it is stored in memory,
397 * i.e. little-endian 32-bit), chain[i].p contains the address of that
398 * number (it points into struct inode for i==0 and into the bh->b_data
399 * for i>0) and chain[i].bh points to the buffer_head of i-th indirect
400 * block for i>0 and NULL for i==0. In other words, it holds the block
401 * numbers of the chain, addresses they were taken from (and where we can
402 * verify that chain did not change) and buffer_heads hosting these
405 * Function stops when it stumbles upon zero pointer (absent block)
406 * (pointer to last triple returned, *@err == 0)
407 * or when it gets an IO error reading an indirect block
408 * (ditto, *@err == -EIO)
409 * or when it reads all @depth-1 indirect blocks successfully and finds
410 * the whole chain, all way to the data (returns %NULL, *err == 0).
412 * Need to be called with
413 * down_read(&EXT4_I(inode)->i_data_sem)
415 static Indirect
*ext4_get_branch(struct inode
*inode
, int depth
,
416 ext4_lblk_t
*offsets
,
417 Indirect chain
[4], int *err
)
419 struct super_block
*sb
= inode
->i_sb
;
421 struct buffer_head
*bh
;
424 /* i_data is not going away, no lock needed */
425 add_chain(chain
, NULL
, EXT4_I(inode
)->i_data
+ *offsets
);
429 bh
= sb_getblk(sb
, le32_to_cpu(p
->key
));
433 if (!bh_uptodate_or_lock(bh
)) {
434 if (bh_submit_read(bh
) < 0) {
438 /* validate block references */
439 if (ext4_check_indirect_blockref(inode
, bh
)) {
445 add_chain(++p
, bh
, (__le32
*)bh
->b_data
+ *++offsets
);
459 * ext4_find_near - find a place for allocation with sufficient locality
461 * @ind: descriptor of indirect block.
463 * This function returns the preferred place for block allocation.
464 * It is used when heuristic for sequential allocation fails.
466 * + if there is a block to the left of our position - allocate near it.
467 * + if pointer will live in indirect block - allocate near that block.
468 * + if pointer will live in inode - allocate in the same
471 * In the latter case we colour the starting block by the callers PID to
472 * prevent it from clashing with concurrent allocations for a different inode
473 * in the same block group. The PID is used here so that functionally related
474 * files will be close-by on-disk.
476 * Caller must make sure that @ind is valid and will stay that way.
478 static ext4_fsblk_t
ext4_find_near(struct inode
*inode
, Indirect
*ind
)
480 struct ext4_inode_info
*ei
= EXT4_I(inode
);
481 __le32
*start
= ind
->bh
? (__le32
*) ind
->bh
->b_data
: ei
->i_data
;
483 ext4_fsblk_t bg_start
;
484 ext4_fsblk_t last_block
;
485 ext4_grpblk_t colour
;
486 ext4_group_t block_group
;
487 int flex_size
= ext4_flex_bg_size(EXT4_SB(inode
->i_sb
));
489 /* Try to find previous block */
490 for (p
= ind
->p
- 1; p
>= start
; p
--) {
492 return le32_to_cpu(*p
);
495 /* No such thing, so let's try location of indirect block */
497 return ind
->bh
->b_blocknr
;
500 * It is going to be referred to from the inode itself? OK, just put it
501 * into the same cylinder group then.
503 block_group
= ei
->i_block_group
;
504 if (flex_size
>= EXT4_FLEX_SIZE_DIR_ALLOC_SCHEME
) {
505 block_group
&= ~(flex_size
-1);
506 if (S_ISREG(inode
->i_mode
))
509 bg_start
= ext4_group_first_block_no(inode
->i_sb
, block_group
);
510 last_block
= ext4_blocks_count(EXT4_SB(inode
->i_sb
)->s_es
) - 1;
513 * If we are doing delayed allocation, we don't need take
514 * colour into account.
516 if (test_opt(inode
->i_sb
, DELALLOC
))
519 if (bg_start
+ EXT4_BLOCKS_PER_GROUP(inode
->i_sb
) <= last_block
)
520 colour
= (current
->pid
% 16) *
521 (EXT4_BLOCKS_PER_GROUP(inode
->i_sb
) / 16);
523 colour
= (current
->pid
% 16) * ((last_block
- bg_start
) / 16);
524 return bg_start
+ colour
;
528 * ext4_find_goal - find a preferred place for allocation.
530 * @block: block we want
531 * @partial: pointer to the last triple within a chain
533 * Normally this function find the preferred place for block allocation,
535 * Because this is only used for non-extent files, we limit the block nr
538 static ext4_fsblk_t
ext4_find_goal(struct inode
*inode
, ext4_lblk_t block
,
544 * XXX need to get goal block from mballoc's data structures
547 goal
= ext4_find_near(inode
, partial
);
548 goal
= goal
& EXT4_MAX_BLOCK_FILE_PHYS
;
553 * ext4_blks_to_allocate: Look up the block map and count the number
554 * of direct blocks need to be allocated for the given branch.
556 * @branch: chain of indirect blocks
557 * @k: number of blocks need for indirect blocks
558 * @blks: number of data blocks to be mapped.
559 * @blocks_to_boundary: the offset in the indirect block
561 * return the total number of blocks to be allocate, including the
562 * direct and indirect blocks.
564 static int ext4_blks_to_allocate(Indirect
*branch
, int k
, unsigned int blks
,
565 int blocks_to_boundary
)
567 unsigned int count
= 0;
570 * Simple case, [t,d]Indirect block(s) has not allocated yet
571 * then it's clear blocks on that path have not allocated
574 /* right now we don't handle cross boundary allocation */
575 if (blks
< blocks_to_boundary
+ 1)
578 count
+= blocks_to_boundary
+ 1;
583 while (count
< blks
&& count
<= blocks_to_boundary
&&
584 le32_to_cpu(*(branch
[0].p
+ count
)) == 0) {
591 * ext4_alloc_blocks: multiple allocate blocks needed for a branch
592 * @indirect_blks: the number of blocks need to allocate for indirect
595 * @new_blocks: on return it will store the new block numbers for
596 * the indirect blocks(if needed) and the first direct block,
597 * @blks: on return it will store the total number of allocated
600 static int ext4_alloc_blocks(handle_t
*handle
, struct inode
*inode
,
601 ext4_lblk_t iblock
, ext4_fsblk_t goal
,
602 int indirect_blks
, int blks
,
603 ext4_fsblk_t new_blocks
[4], int *err
)
605 struct ext4_allocation_request ar
;
607 unsigned long count
= 0, blk_allocated
= 0;
609 ext4_fsblk_t current_block
= 0;
613 * Here we try to allocate the requested multiple blocks at once,
614 * on a best-effort basis.
615 * To build a branch, we should allocate blocks for
616 * the indirect blocks(if not allocated yet), and at least
617 * the first direct block of this branch. That's the
618 * minimum number of blocks need to allocate(required)
620 /* first we try to allocate the indirect blocks */
621 target
= indirect_blks
;
624 /* allocating blocks for indirect blocks and direct blocks */
625 current_block
= ext4_new_meta_blocks(handle
, inode
,
630 if (unlikely(current_block
+ count
> EXT4_MAX_BLOCK_FILE_PHYS
)) {
631 EXT4_ERROR_INODE(inode
,
632 "current_block %llu + count %lu > %d!",
633 current_block
, count
,
634 EXT4_MAX_BLOCK_FILE_PHYS
);
640 /* allocate blocks for indirect blocks */
641 while (index
< indirect_blks
&& count
) {
642 new_blocks
[index
++] = current_block
++;
647 * save the new block number
648 * for the first direct block
650 new_blocks
[index
] = current_block
;
651 printk(KERN_INFO
"%s returned more blocks than "
652 "requested\n", __func__
);
658 target
= blks
- count
;
659 blk_allocated
= count
;
662 /* Now allocate data blocks */
663 memset(&ar
, 0, sizeof(ar
));
668 if (S_ISREG(inode
->i_mode
))
669 /* enable in-core preallocation only for regular files */
670 ar
.flags
= EXT4_MB_HINT_DATA
;
672 current_block
= ext4_mb_new_blocks(handle
, &ar
, err
);
673 if (unlikely(current_block
+ ar
.len
> EXT4_MAX_BLOCK_FILE_PHYS
)) {
674 EXT4_ERROR_INODE(inode
,
675 "current_block %llu + ar.len %d > %d!",
676 current_block
, ar
.len
,
677 EXT4_MAX_BLOCK_FILE_PHYS
);
682 if (*err
&& (target
== blks
)) {
684 * if the allocation failed and we didn't allocate
690 if (target
== blks
) {
692 * save the new block number
693 * for the first direct block
695 new_blocks
[index
] = current_block
;
697 blk_allocated
+= ar
.len
;
700 /* total number of blocks allocated for direct blocks */
705 for (i
= 0; i
< index
; i
++)
706 ext4_free_blocks(handle
, inode
, 0, new_blocks
[i
], 1, 0);
711 * ext4_alloc_branch - allocate and set up a chain of blocks.
713 * @indirect_blks: number of allocated indirect blocks
714 * @blks: number of allocated direct blocks
715 * @offsets: offsets (in the blocks) to store the pointers to next.
716 * @branch: place to store the chain in.
718 * This function allocates blocks, zeroes out all but the last one,
719 * links them into chain and (if we are synchronous) writes them to disk.
720 * In other words, it prepares a branch that can be spliced onto the
721 * inode. It stores the information about that chain in the branch[], in
722 * the same format as ext4_get_branch() would do. We are calling it after
723 * we had read the existing part of chain and partial points to the last
724 * triple of that (one with zero ->key). Upon the exit we have the same
725 * picture as after the successful ext4_get_block(), except that in one
726 * place chain is disconnected - *branch->p is still zero (we did not
727 * set the last link), but branch->key contains the number that should
728 * be placed into *branch->p to fill that gap.
730 * If allocation fails we free all blocks we've allocated (and forget
731 * their buffer_heads) and return the error value the from failed
732 * ext4_alloc_block() (normally -ENOSPC). Otherwise we set the chain
733 * as described above and return 0.
735 static int ext4_alloc_branch(handle_t
*handle
, struct inode
*inode
,
736 ext4_lblk_t iblock
, int indirect_blks
,
737 int *blks
, ext4_fsblk_t goal
,
738 ext4_lblk_t
*offsets
, Indirect
*branch
)
740 int blocksize
= inode
->i_sb
->s_blocksize
;
743 struct buffer_head
*bh
;
745 ext4_fsblk_t new_blocks
[4];
746 ext4_fsblk_t current_block
;
748 num
= ext4_alloc_blocks(handle
, inode
, iblock
, goal
, indirect_blks
,
749 *blks
, new_blocks
, &err
);
753 branch
[0].key
= cpu_to_le32(new_blocks
[0]);
755 * metadata blocks and data blocks are allocated.
757 for (n
= 1; n
<= indirect_blks
; n
++) {
759 * Get buffer_head for parent block, zero it out
760 * and set the pointer to new one, then send
763 bh
= sb_getblk(inode
->i_sb
, new_blocks
[n
-1]);
771 BUFFER_TRACE(bh
, "call get_create_access");
772 err
= ext4_journal_get_create_access(handle
, bh
);
774 /* Don't brelse(bh) here; it's done in
775 * ext4_journal_forget() below */
780 memset(bh
->b_data
, 0, blocksize
);
781 branch
[n
].p
= (__le32
*) bh
->b_data
+ offsets
[n
];
782 branch
[n
].key
= cpu_to_le32(new_blocks
[n
]);
783 *branch
[n
].p
= branch
[n
].key
;
784 if (n
== indirect_blks
) {
785 current_block
= new_blocks
[n
];
787 * End of chain, update the last new metablock of
788 * the chain to point to the new allocated
789 * data blocks numbers
791 for (i
= 1; i
< num
; i
++)
792 *(branch
[n
].p
+ i
) = cpu_to_le32(++current_block
);
794 BUFFER_TRACE(bh
, "marking uptodate");
795 set_buffer_uptodate(bh
);
798 BUFFER_TRACE(bh
, "call ext4_handle_dirty_metadata");
799 err
= ext4_handle_dirty_metadata(handle
, inode
, bh
);
806 /* Allocation failed, free what we already allocated */
807 ext4_free_blocks(handle
, inode
, 0, new_blocks
[0], 1, 0);
808 for (i
= 1; i
<= n
; i
++) {
810 * branch[i].bh is newly allocated, so there is no
811 * need to revoke the block, which is why we don't
812 * need to set EXT4_FREE_BLOCKS_METADATA.
814 ext4_free_blocks(handle
, inode
, 0, new_blocks
[i
], 1,
815 EXT4_FREE_BLOCKS_FORGET
);
817 for (i
= n
+1; i
< indirect_blks
; i
++)
818 ext4_free_blocks(handle
, inode
, 0, new_blocks
[i
], 1, 0);
820 ext4_free_blocks(handle
, inode
, 0, new_blocks
[i
], num
, 0);
826 * ext4_splice_branch - splice the allocated branch onto inode.
828 * @block: (logical) number of block we are adding
829 * @chain: chain of indirect blocks (with a missing link - see
831 * @where: location of missing link
832 * @num: number of indirect blocks we are adding
833 * @blks: number of direct blocks we are adding
835 * This function fills the missing link and does all housekeeping needed in
836 * inode (->i_blocks, etc.). In case of success we end up with the full
837 * chain to new block and return 0.
839 static int ext4_splice_branch(handle_t
*handle
, struct inode
*inode
,
840 ext4_lblk_t block
, Indirect
*where
, int num
,
845 ext4_fsblk_t current_block
;
848 * If we're splicing into a [td]indirect block (as opposed to the
849 * inode) then we need to get write access to the [td]indirect block
853 BUFFER_TRACE(where
->bh
, "get_write_access");
854 err
= ext4_journal_get_write_access(handle
, where
->bh
);
860 *where
->p
= where
->key
;
863 * Update the host buffer_head or inode to point to more just allocated
864 * direct blocks blocks
866 if (num
== 0 && blks
> 1) {
867 current_block
= le32_to_cpu(where
->key
) + 1;
868 for (i
= 1; i
< blks
; i
++)
869 *(where
->p
+ i
) = cpu_to_le32(current_block
++);
872 /* We are done with atomic stuff, now do the rest of housekeeping */
873 /* had we spliced it onto indirect block? */
876 * If we spliced it onto an indirect block, we haven't
877 * altered the inode. Note however that if it is being spliced
878 * onto an indirect block at the very end of the file (the
879 * file is growing) then we *will* alter the inode to reflect
880 * the new i_size. But that is not done here - it is done in
881 * generic_commit_write->__mark_inode_dirty->ext4_dirty_inode.
883 jbd_debug(5, "splicing indirect only\n");
884 BUFFER_TRACE(where
->bh
, "call ext4_handle_dirty_metadata");
885 err
= ext4_handle_dirty_metadata(handle
, inode
, where
->bh
);
890 * OK, we spliced it into the inode itself on a direct block.
892 ext4_mark_inode_dirty(handle
, inode
);
893 jbd_debug(5, "splicing direct\n");
898 for (i
= 1; i
<= num
; i
++) {
900 * branch[i].bh is newly allocated, so there is no
901 * need to revoke the block, which is why we don't
902 * need to set EXT4_FREE_BLOCKS_METADATA.
904 ext4_free_blocks(handle
, inode
, where
[i
].bh
, 0, 1,
905 EXT4_FREE_BLOCKS_FORGET
);
907 ext4_free_blocks(handle
, inode
, 0, le32_to_cpu(where
[num
].key
),
914 * The ext4_ind_map_blocks() function handles non-extents inodes
915 * (i.e., using the traditional indirect/double-indirect i_blocks
916 * scheme) for ext4_map_blocks().
918 * Allocation strategy is simple: if we have to allocate something, we will
919 * have to go the whole way to leaf. So let's do it before attaching anything
920 * to tree, set linkage between the newborn blocks, write them if sync is
921 * required, recheck the path, free and repeat if check fails, otherwise
922 * set the last missing link (that will protect us from any truncate-generated
923 * removals - all blocks on the path are immune now) and possibly force the
924 * write on the parent block.
925 * That has a nice additional property: no special recovery from the failed
926 * allocations is needed - we simply release blocks and do not touch anything
927 * reachable from inode.
929 * `handle' can be NULL if create == 0.
931 * return > 0, # of blocks mapped or allocated.
932 * return = 0, if plain lookup failed.
933 * return < 0, error case.
935 * The ext4_ind_get_blocks() function should be called with
936 * down_write(&EXT4_I(inode)->i_data_sem) if allocating filesystem
937 * blocks (i.e., flags has EXT4_GET_BLOCKS_CREATE set) or
938 * down_read(&EXT4_I(inode)->i_data_sem) if not allocating file system
941 static int ext4_ind_map_blocks(handle_t
*handle
, struct inode
*inode
,
942 struct ext4_map_blocks
*map
,
946 ext4_lblk_t offsets
[4];
951 int blocks_to_boundary
= 0;
954 ext4_fsblk_t first_block
= 0;
956 J_ASSERT(!(ext4_test_inode_flag(inode
, EXT4_INODE_EXTENTS
)));
957 J_ASSERT(handle
!= NULL
|| (flags
& EXT4_GET_BLOCKS_CREATE
) == 0);
958 depth
= ext4_block_to_path(inode
, map
->m_lblk
, offsets
,
959 &blocks_to_boundary
);
964 partial
= ext4_get_branch(inode
, depth
, offsets
, chain
, &err
);
966 /* Simplest case - block found, no allocation needed */
968 first_block
= le32_to_cpu(chain
[depth
- 1].key
);
971 while (count
< map
->m_len
&& count
<= blocks_to_boundary
) {
974 blk
= le32_to_cpu(*(chain
[depth
-1].p
+ count
));
976 if (blk
== first_block
+ count
)
984 /* Next simple case - plain lookup or failed read of indirect block */
985 if ((flags
& EXT4_GET_BLOCKS_CREATE
) == 0 || err
== -EIO
)
989 * Okay, we need to do block allocation.
991 goal
= ext4_find_goal(inode
, map
->m_lblk
, partial
);
993 /* the number of blocks need to allocate for [d,t]indirect blocks */
994 indirect_blks
= (chain
+ depth
) - partial
- 1;
997 * Next look up the indirect map to count the totoal number of
998 * direct blocks to allocate for this branch.
1000 count
= ext4_blks_to_allocate(partial
, indirect_blks
,
1001 map
->m_len
, blocks_to_boundary
);
1003 * Block out ext4_truncate while we alter the tree
1005 err
= ext4_alloc_branch(handle
, inode
, map
->m_lblk
, indirect_blks
,
1007 offsets
+ (partial
- chain
), partial
);
1010 * The ext4_splice_branch call will free and forget any buffers
1011 * on the new chain if there is a failure, but that risks using
1012 * up transaction credits, especially for bitmaps where the
1013 * credits cannot be returned. Can we handle this somehow? We
1014 * may need to return -EAGAIN upwards in the worst case. --sct
1017 err
= ext4_splice_branch(handle
, inode
, map
->m_lblk
,
1018 partial
, indirect_blks
, count
);
1022 map
->m_flags
|= EXT4_MAP_NEW
;
1024 ext4_update_inode_fsync_trans(handle
, inode
, 1);
1026 map
->m_flags
|= EXT4_MAP_MAPPED
;
1027 map
->m_pblk
= le32_to_cpu(chain
[depth
-1].key
);
1029 if (count
> blocks_to_boundary
)
1030 map
->m_flags
|= EXT4_MAP_BOUNDARY
;
1032 /* Clean up and exit */
1033 partial
= chain
+ depth
- 1; /* the whole chain */
1035 while (partial
> chain
) {
1036 BUFFER_TRACE(partial
->bh
, "call brelse");
1037 brelse(partial
->bh
);
1045 qsize_t
*ext4_get_reserved_space(struct inode
*inode
)
1047 return &EXT4_I(inode
)->i_reserved_quota
;
1052 * Calculate the number of metadata blocks need to reserve
1053 * to allocate a new block at @lblocks for non extent file based file
1055 static int ext4_indirect_calc_metadata_amount(struct inode
*inode
,
1058 struct ext4_inode_info
*ei
= EXT4_I(inode
);
1059 sector_t dind_mask
= ~((sector_t
)EXT4_ADDR_PER_BLOCK(inode
->i_sb
) - 1);
1062 if (lblock
< EXT4_NDIR_BLOCKS
)
1065 lblock
-= EXT4_NDIR_BLOCKS
;
1067 if (ei
->i_da_metadata_calc_len
&&
1068 (lblock
& dind_mask
) == ei
->i_da_metadata_calc_last_lblock
) {
1069 ei
->i_da_metadata_calc_len
++;
1072 ei
->i_da_metadata_calc_last_lblock
= lblock
& dind_mask
;
1073 ei
->i_da_metadata_calc_len
= 1;
1074 blk_bits
= order_base_2(lblock
);
1075 return (blk_bits
/ EXT4_ADDR_PER_BLOCK_BITS(inode
->i_sb
)) + 1;
1079 * Calculate the number of metadata blocks need to reserve
1080 * to allocate a block located at @lblock
1082 static int ext4_calc_metadata_amount(struct inode
*inode
, sector_t lblock
)
1084 if (ext4_test_inode_flag(inode
, EXT4_INODE_EXTENTS
))
1085 return ext4_ext_calc_metadata_amount(inode
, lblock
);
1087 return ext4_indirect_calc_metadata_amount(inode
, lblock
);
1091 * Called with i_data_sem down, which is important since we can call
1092 * ext4_discard_preallocations() from here.
1094 void ext4_da_update_reserve_space(struct inode
*inode
,
1095 int used
, int quota_claim
)
1097 struct ext4_sb_info
*sbi
= EXT4_SB(inode
->i_sb
);
1098 struct ext4_inode_info
*ei
= EXT4_I(inode
);
1100 spin_lock(&ei
->i_block_reservation_lock
);
1101 trace_ext4_da_update_reserve_space(inode
, used
);
1102 if (unlikely(used
> ei
->i_reserved_data_blocks
)) {
1103 ext4_msg(inode
->i_sb
, KERN_NOTICE
, "%s: ino %lu, used %d "
1104 "with only %d reserved data blocks\n",
1105 __func__
, inode
->i_ino
, used
,
1106 ei
->i_reserved_data_blocks
);
1108 used
= ei
->i_reserved_data_blocks
;
1111 /* Update per-inode reservations */
1112 ei
->i_reserved_data_blocks
-= used
;
1113 ei
->i_reserved_meta_blocks
-= ei
->i_allocated_meta_blocks
;
1114 percpu_counter_sub(&sbi
->s_dirtyblocks_counter
,
1115 used
+ ei
->i_allocated_meta_blocks
);
1116 ei
->i_allocated_meta_blocks
= 0;
1118 if (ei
->i_reserved_data_blocks
== 0) {
1120 * We can release all of the reserved metadata blocks
1121 * only when we have written all of the delayed
1122 * allocation blocks.
1124 percpu_counter_sub(&sbi
->s_dirtyblocks_counter
,
1125 ei
->i_reserved_meta_blocks
);
1126 ei
->i_reserved_meta_blocks
= 0;
1127 ei
->i_da_metadata_calc_len
= 0;
1129 spin_unlock(&EXT4_I(inode
)->i_block_reservation_lock
);
1131 /* Update quota subsystem for data blocks */
1133 dquot_claim_block(inode
, used
);
1136 * We did fallocate with an offset that is already delayed
1137 * allocated. So on delayed allocated writeback we should
1138 * not re-claim the quota for fallocated blocks.
1140 dquot_release_reservation_block(inode
, used
);
1144 * If we have done all the pending block allocations and if
1145 * there aren't any writers on the inode, we can discard the
1146 * inode's preallocations.
1148 if ((ei
->i_reserved_data_blocks
== 0) &&
1149 (atomic_read(&inode
->i_writecount
) == 0))
1150 ext4_discard_preallocations(inode
);
1153 static int __check_block_validity(struct inode
*inode
, const char *func
,
1155 struct ext4_map_blocks
*map
)
1157 if (!ext4_data_block_valid(EXT4_SB(inode
->i_sb
), map
->m_pblk
,
1159 ext4_error_inode(inode
, func
, line
, map
->m_pblk
,
1160 "lblock %lu mapped to illegal pblock "
1161 "(length %d)", (unsigned long) map
->m_lblk
,
1168 #define check_block_validity(inode, map) \
1169 __check_block_validity((inode), __func__, __LINE__, (map))
1172 * Return the number of contiguous dirty pages in a given inode
1173 * starting at page frame idx.
1175 static pgoff_t
ext4_num_dirty_pages(struct inode
*inode
, pgoff_t idx
,
1176 unsigned int max_pages
)
1178 struct address_space
*mapping
= inode
->i_mapping
;
1180 struct pagevec pvec
;
1182 int i
, nr_pages
, done
= 0;
1186 pagevec_init(&pvec
, 0);
1189 nr_pages
= pagevec_lookup_tag(&pvec
, mapping
, &index
,
1190 PAGECACHE_TAG_DIRTY
,
1191 (pgoff_t
)PAGEVEC_SIZE
);
1194 for (i
= 0; i
< nr_pages
; i
++) {
1195 struct page
*page
= pvec
.pages
[i
];
1196 struct buffer_head
*bh
, *head
;
1199 if (unlikely(page
->mapping
!= mapping
) ||
1201 PageWriteback(page
) ||
1202 page
->index
!= idx
) {
1207 if (page_has_buffers(page
)) {
1208 bh
= head
= page_buffers(page
);
1210 if (!buffer_delay(bh
) &&
1211 !buffer_unwritten(bh
))
1213 bh
= bh
->b_this_page
;
1214 } while (!done
&& (bh
!= head
));
1221 if (num
>= max_pages
) {
1226 pagevec_release(&pvec
);
1232 * The ext4_map_blocks() function tries to look up the requested blocks,
1233 * and returns if the blocks are already mapped.
1235 * Otherwise it takes the write lock of the i_data_sem and allocate blocks
1236 * and store the allocated blocks in the result buffer head and mark it
1239 * If file type is extents based, it will call ext4_ext_map_blocks(),
1240 * Otherwise, call with ext4_ind_map_blocks() to handle indirect mapping
1243 * On success, it returns the number of blocks being mapped or allocate.
1244 * if create==0 and the blocks are pre-allocated and uninitialized block,
1245 * the result buffer head is unmapped. If the create ==1, it will make sure
1246 * the buffer head is mapped.
1248 * It returns 0 if plain look up failed (blocks have not been allocated), in
1249 * that casem, buffer head is unmapped
1251 * It returns the error in case of allocation failure.
1253 int ext4_map_blocks(handle_t
*handle
, struct inode
*inode
,
1254 struct ext4_map_blocks
*map
, int flags
)
1259 ext_debug("ext4_map_blocks(): inode %lu, flag %d, max_blocks %u,"
1260 "logical block %lu\n", inode
->i_ino
, flags
, map
->m_len
,
1261 (unsigned long) map
->m_lblk
);
1263 * Try to see if we can get the block without requesting a new
1264 * file system block.
1266 down_read((&EXT4_I(inode
)->i_data_sem
));
1267 if (ext4_test_inode_flag(inode
, EXT4_INODE_EXTENTS
)) {
1268 retval
= ext4_ext_map_blocks(handle
, inode
, map
, 0);
1270 retval
= ext4_ind_map_blocks(handle
, inode
, map
, 0);
1272 up_read((&EXT4_I(inode
)->i_data_sem
));
1274 if (retval
> 0 && map
->m_flags
& EXT4_MAP_MAPPED
) {
1275 int ret
= check_block_validity(inode
, map
);
1280 /* If it is only a block(s) look up */
1281 if ((flags
& EXT4_GET_BLOCKS_CREATE
) == 0)
1285 * Returns if the blocks have already allocated
1287 * Note that if blocks have been preallocated
1288 * ext4_ext_get_block() returns th create = 0
1289 * with buffer head unmapped.
1291 if (retval
> 0 && map
->m_flags
& EXT4_MAP_MAPPED
)
1295 * When we call get_blocks without the create flag, the
1296 * BH_Unwritten flag could have gotten set if the blocks
1297 * requested were part of a uninitialized extent. We need to
1298 * clear this flag now that we are committed to convert all or
1299 * part of the uninitialized extent to be an initialized
1300 * extent. This is because we need to avoid the combination
1301 * of BH_Unwritten and BH_Mapped flags being simultaneously
1302 * set on the buffer_head.
1304 map
->m_flags
&= ~EXT4_MAP_UNWRITTEN
;
1307 * New blocks allocate and/or writing to uninitialized extent
1308 * will possibly result in updating i_data, so we take
1309 * the write lock of i_data_sem, and call get_blocks()
1310 * with create == 1 flag.
1312 down_write((&EXT4_I(inode
)->i_data_sem
));
1315 * if the caller is from delayed allocation writeout path
1316 * we have already reserved fs blocks for allocation
1317 * let the underlying get_block() function know to
1318 * avoid double accounting
1320 if (flags
& EXT4_GET_BLOCKS_DELALLOC_RESERVE
)
1321 EXT4_I(inode
)->i_delalloc_reserved_flag
= 1;
1323 * We need to check for EXT4 here because migrate
1324 * could have changed the inode type in between
1326 if (ext4_test_inode_flag(inode
, EXT4_INODE_EXTENTS
)) {
1327 retval
= ext4_ext_map_blocks(handle
, inode
, map
, flags
);
1329 retval
= ext4_ind_map_blocks(handle
, inode
, map
, flags
);
1331 if (retval
> 0 && map
->m_flags
& EXT4_MAP_NEW
) {
1333 * We allocated new blocks which will result in
1334 * i_data's format changing. Force the migrate
1335 * to fail by clearing migrate flags
1337 ext4_clear_inode_state(inode
, EXT4_STATE_EXT_MIGRATE
);
1341 * Update reserved blocks/metadata blocks after successful
1342 * block allocation which had been deferred till now. We don't
1343 * support fallocate for non extent files. So we can update
1344 * reserve space here.
1347 (flags
& EXT4_GET_BLOCKS_DELALLOC_RESERVE
))
1348 ext4_da_update_reserve_space(inode
, retval
, 1);
1350 if (flags
& EXT4_GET_BLOCKS_DELALLOC_RESERVE
)
1351 EXT4_I(inode
)->i_delalloc_reserved_flag
= 0;
1353 up_write((&EXT4_I(inode
)->i_data_sem
));
1354 if (retval
> 0 && map
->m_flags
& EXT4_MAP_MAPPED
) {
1355 int ret
= check_block_validity(inode
, map
);
1362 /* Maximum number of blocks we map for direct IO at once. */
1363 #define DIO_MAX_BLOCKS 4096
1365 static int _ext4_get_block(struct inode
*inode
, sector_t iblock
,
1366 struct buffer_head
*bh
, int flags
)
1368 handle_t
*handle
= ext4_journal_current_handle();
1369 struct ext4_map_blocks map
;
1370 int ret
= 0, started
= 0;
1373 map
.m_lblk
= iblock
;
1374 map
.m_len
= bh
->b_size
>> inode
->i_blkbits
;
1376 if (flags
&& !handle
) {
1377 /* Direct IO write... */
1378 if (map
.m_len
> DIO_MAX_BLOCKS
)
1379 map
.m_len
= DIO_MAX_BLOCKS
;
1380 dio_credits
= ext4_chunk_trans_blocks(inode
, map
.m_len
);
1381 handle
= ext4_journal_start(inode
, dio_credits
);
1382 if (IS_ERR(handle
)) {
1383 ret
= PTR_ERR(handle
);
1389 ret
= ext4_map_blocks(handle
, inode
, &map
, flags
);
1391 map_bh(bh
, inode
->i_sb
, map
.m_pblk
);
1392 bh
->b_state
= (bh
->b_state
& ~EXT4_MAP_FLAGS
) | map
.m_flags
;
1393 bh
->b_size
= inode
->i_sb
->s_blocksize
* map
.m_len
;
1397 ext4_journal_stop(handle
);
1401 int ext4_get_block(struct inode
*inode
, sector_t iblock
,
1402 struct buffer_head
*bh
, int create
)
1404 return _ext4_get_block(inode
, iblock
, bh
,
1405 create
? EXT4_GET_BLOCKS_CREATE
: 0);
1409 * `handle' can be NULL if create is zero
1411 struct buffer_head
*ext4_getblk(handle_t
*handle
, struct inode
*inode
,
1412 ext4_lblk_t block
, int create
, int *errp
)
1414 struct ext4_map_blocks map
;
1415 struct buffer_head
*bh
;
1418 J_ASSERT(handle
!= NULL
|| create
== 0);
1422 err
= ext4_map_blocks(handle
, inode
, &map
,
1423 create
? EXT4_GET_BLOCKS_CREATE
: 0);
1431 bh
= sb_getblk(inode
->i_sb
, map
.m_pblk
);
1436 if (map
.m_flags
& EXT4_MAP_NEW
) {
1437 J_ASSERT(create
!= 0);
1438 J_ASSERT(handle
!= NULL
);
1441 * Now that we do not always journal data, we should
1442 * keep in mind whether this should always journal the
1443 * new buffer as metadata. For now, regular file
1444 * writes use ext4_get_block instead, so it's not a
1448 BUFFER_TRACE(bh
, "call get_create_access");
1449 fatal
= ext4_journal_get_create_access(handle
, bh
);
1450 if (!fatal
&& !buffer_uptodate(bh
)) {
1451 memset(bh
->b_data
, 0, inode
->i_sb
->s_blocksize
);
1452 set_buffer_uptodate(bh
);
1455 BUFFER_TRACE(bh
, "call ext4_handle_dirty_metadata");
1456 err
= ext4_handle_dirty_metadata(handle
, inode
, bh
);
1460 BUFFER_TRACE(bh
, "not a new buffer");
1470 struct buffer_head
*ext4_bread(handle_t
*handle
, struct inode
*inode
,
1471 ext4_lblk_t block
, int create
, int *err
)
1473 struct buffer_head
*bh
;
1475 bh
= ext4_getblk(handle
, inode
, block
, create
, err
);
1478 if (buffer_uptodate(bh
))
1480 ll_rw_block(READ_META
, 1, &bh
);
1482 if (buffer_uptodate(bh
))
1489 static int walk_page_buffers(handle_t
*handle
,
1490 struct buffer_head
*head
,
1494 int (*fn
)(handle_t
*handle
,
1495 struct buffer_head
*bh
))
1497 struct buffer_head
*bh
;
1498 unsigned block_start
, block_end
;
1499 unsigned blocksize
= head
->b_size
;
1501 struct buffer_head
*next
;
1503 for (bh
= head
, block_start
= 0;
1504 ret
== 0 && (bh
!= head
|| !block_start
);
1505 block_start
= block_end
, bh
= next
) {
1506 next
= bh
->b_this_page
;
1507 block_end
= block_start
+ blocksize
;
1508 if (block_end
<= from
|| block_start
>= to
) {
1509 if (partial
&& !buffer_uptodate(bh
))
1513 err
= (*fn
)(handle
, bh
);
1521 * To preserve ordering, it is essential that the hole instantiation and
1522 * the data write be encapsulated in a single transaction. We cannot
1523 * close off a transaction and start a new one between the ext4_get_block()
1524 * and the commit_write(). So doing the jbd2_journal_start at the start of
1525 * prepare_write() is the right place.
1527 * Also, this function can nest inside ext4_writepage() ->
1528 * block_write_full_page(). In that case, we *know* that ext4_writepage()
1529 * has generated enough buffer credits to do the whole page. So we won't
1530 * block on the journal in that case, which is good, because the caller may
1533 * By accident, ext4 can be reentered when a transaction is open via
1534 * quota file writes. If we were to commit the transaction while thus
1535 * reentered, there can be a deadlock - we would be holding a quota
1536 * lock, and the commit would never complete if another thread had a
1537 * transaction open and was blocking on the quota lock - a ranking
1540 * So what we do is to rely on the fact that jbd2_journal_stop/journal_start
1541 * will _not_ run commit under these circumstances because handle->h_ref
1542 * is elevated. We'll still have enough credits for the tiny quotafile
1545 static int do_journal_get_write_access(handle_t
*handle
,
1546 struct buffer_head
*bh
)
1548 int dirty
= buffer_dirty(bh
);
1551 if (!buffer_mapped(bh
) || buffer_freed(bh
))
1554 * __block_prepare_write() could have dirtied some buffers. Clean
1555 * the dirty bit as jbd2_journal_get_write_access() could complain
1556 * otherwise about fs integrity issues. Setting of the dirty bit
1557 * by __block_prepare_write() isn't a real problem here as we clear
1558 * the bit before releasing a page lock and thus writeback cannot
1559 * ever write the buffer.
1562 clear_buffer_dirty(bh
);
1563 ret
= ext4_journal_get_write_access(handle
, bh
);
1565 ret
= ext4_handle_dirty_metadata(handle
, NULL
, bh
);
1570 * Truncate blocks that were not used by write. We have to truncate the
1571 * pagecache as well so that corresponding buffers get properly unmapped.
1573 static void ext4_truncate_failed_write(struct inode
*inode
)
1575 truncate_inode_pages(inode
->i_mapping
, inode
->i_size
);
1576 ext4_truncate(inode
);
1579 static int ext4_get_block_write(struct inode
*inode
, sector_t iblock
,
1580 struct buffer_head
*bh_result
, int create
);
1581 static int ext4_write_begin(struct file
*file
, struct address_space
*mapping
,
1582 loff_t pos
, unsigned len
, unsigned flags
,
1583 struct page
**pagep
, void **fsdata
)
1585 struct inode
*inode
= mapping
->host
;
1586 int ret
, needed_blocks
;
1593 trace_ext4_write_begin(inode
, pos
, len
, flags
);
1595 * Reserve one block more for addition to orphan list in case
1596 * we allocate blocks but write fails for some reason
1598 needed_blocks
= ext4_writepage_trans_blocks(inode
) + 1;
1599 index
= pos
>> PAGE_CACHE_SHIFT
;
1600 from
= pos
& (PAGE_CACHE_SIZE
- 1);
1604 handle
= ext4_journal_start(inode
, needed_blocks
);
1605 if (IS_ERR(handle
)) {
1606 ret
= PTR_ERR(handle
);
1610 /* We cannot recurse into the filesystem as the transaction is already
1612 flags
|= AOP_FLAG_NOFS
;
1614 page
= grab_cache_page_write_begin(mapping
, index
, flags
);
1616 ext4_journal_stop(handle
);
1622 if (ext4_should_dioread_nolock(inode
))
1623 ret
= __block_write_begin(page
, pos
, len
, ext4_get_block_write
);
1625 ret
= __block_write_begin(page
, pos
, len
, ext4_get_block
);
1627 if (!ret
&& ext4_should_journal_data(inode
)) {
1628 ret
= walk_page_buffers(handle
, page_buffers(page
),
1629 from
, to
, NULL
, do_journal_get_write_access
);
1634 page_cache_release(page
);
1636 * __block_write_begin may have instantiated a few blocks
1637 * outside i_size. Trim these off again. Don't need
1638 * i_size_read because we hold i_mutex.
1640 * Add inode to orphan list in case we crash before
1643 if (pos
+ len
> inode
->i_size
&& ext4_can_truncate(inode
))
1644 ext4_orphan_add(handle
, inode
);
1646 ext4_journal_stop(handle
);
1647 if (pos
+ len
> inode
->i_size
) {
1648 ext4_truncate_failed_write(inode
);
1650 * If truncate failed early the inode might
1651 * still be on the orphan list; we need to
1652 * make sure the inode is removed from the
1653 * orphan list in that case.
1656 ext4_orphan_del(NULL
, inode
);
1660 if (ret
== -ENOSPC
&& ext4_should_retry_alloc(inode
->i_sb
, &retries
))
1666 /* For write_end() in data=journal mode */
1667 static int write_end_fn(handle_t
*handle
, struct buffer_head
*bh
)
1669 if (!buffer_mapped(bh
) || buffer_freed(bh
))
1671 set_buffer_uptodate(bh
);
1672 return ext4_handle_dirty_metadata(handle
, NULL
, bh
);
1675 static int ext4_generic_write_end(struct file
*file
,
1676 struct address_space
*mapping
,
1677 loff_t pos
, unsigned len
, unsigned copied
,
1678 struct page
*page
, void *fsdata
)
1680 int i_size_changed
= 0;
1681 struct inode
*inode
= mapping
->host
;
1682 handle_t
*handle
= ext4_journal_current_handle();
1684 copied
= block_write_end(file
, mapping
, pos
, len
, copied
, page
, fsdata
);
1687 * No need to use i_size_read() here, the i_size
1688 * cannot change under us because we hold i_mutex.
1690 * But it's important to update i_size while still holding page lock:
1691 * page writeout could otherwise come in and zero beyond i_size.
1693 if (pos
+ copied
> inode
->i_size
) {
1694 i_size_write(inode
, pos
+ copied
);
1698 if (pos
+ copied
> EXT4_I(inode
)->i_disksize
) {
1699 /* We need to mark inode dirty even if
1700 * new_i_size is less that inode->i_size
1701 * bu greater than i_disksize.(hint delalloc)
1703 ext4_update_i_disksize(inode
, (pos
+ copied
));
1707 page_cache_release(page
);
1710 * Don't mark the inode dirty under page lock. First, it unnecessarily
1711 * makes the holding time of page lock longer. Second, it forces lock
1712 * ordering of page lock and transaction start for journaling
1716 ext4_mark_inode_dirty(handle
, inode
);
1722 * We need to pick up the new inode size which generic_commit_write gave us
1723 * `file' can be NULL - eg, when called from page_symlink().
1725 * ext4 never places buffers on inode->i_mapping->private_list. metadata
1726 * buffers are managed internally.
1728 static int ext4_ordered_write_end(struct file
*file
,
1729 struct address_space
*mapping
,
1730 loff_t pos
, unsigned len
, unsigned copied
,
1731 struct page
*page
, void *fsdata
)
1733 handle_t
*handle
= ext4_journal_current_handle();
1734 struct inode
*inode
= mapping
->host
;
1737 trace_ext4_ordered_write_end(inode
, pos
, len
, copied
);
1738 ret
= ext4_jbd2_file_inode(handle
, inode
);
1741 ret2
= ext4_generic_write_end(file
, mapping
, pos
, len
, copied
,
1744 if (pos
+ len
> inode
->i_size
&& ext4_can_truncate(inode
))
1745 /* if we have allocated more blocks and copied
1746 * less. We will have blocks allocated outside
1747 * inode->i_size. So truncate them
1749 ext4_orphan_add(handle
, inode
);
1753 ret2
= ext4_journal_stop(handle
);
1757 if (pos
+ len
> inode
->i_size
) {
1758 ext4_truncate_failed_write(inode
);
1760 * If truncate failed early the inode might still be
1761 * on the orphan list; we need to make sure the inode
1762 * is removed from the orphan list in that case.
1765 ext4_orphan_del(NULL
, inode
);
1769 return ret
? ret
: copied
;
1772 static int ext4_writeback_write_end(struct file
*file
,
1773 struct address_space
*mapping
,
1774 loff_t pos
, unsigned len
, unsigned copied
,
1775 struct page
*page
, void *fsdata
)
1777 handle_t
*handle
= ext4_journal_current_handle();
1778 struct inode
*inode
= mapping
->host
;
1781 trace_ext4_writeback_write_end(inode
, pos
, len
, copied
);
1782 ret2
= ext4_generic_write_end(file
, mapping
, pos
, len
, copied
,
1785 if (pos
+ len
> inode
->i_size
&& ext4_can_truncate(inode
))
1786 /* if we have allocated more blocks and copied
1787 * less. We will have blocks allocated outside
1788 * inode->i_size. So truncate them
1790 ext4_orphan_add(handle
, inode
);
1795 ret2
= ext4_journal_stop(handle
);
1799 if (pos
+ len
> inode
->i_size
) {
1800 ext4_truncate_failed_write(inode
);
1802 * If truncate failed early the inode might still be
1803 * on the orphan list; we need to make sure the inode
1804 * is removed from the orphan list in that case.
1807 ext4_orphan_del(NULL
, inode
);
1810 return ret
? ret
: copied
;
1813 static int ext4_journalled_write_end(struct file
*file
,
1814 struct address_space
*mapping
,
1815 loff_t pos
, unsigned len
, unsigned copied
,
1816 struct page
*page
, void *fsdata
)
1818 handle_t
*handle
= ext4_journal_current_handle();
1819 struct inode
*inode
= mapping
->host
;
1825 trace_ext4_journalled_write_end(inode
, pos
, len
, copied
);
1826 from
= pos
& (PAGE_CACHE_SIZE
- 1);
1830 if (!PageUptodate(page
))
1832 page_zero_new_buffers(page
, from
+copied
, to
);
1835 ret
= walk_page_buffers(handle
, page_buffers(page
), from
,
1836 to
, &partial
, write_end_fn
);
1838 SetPageUptodate(page
);
1839 new_i_size
= pos
+ copied
;
1840 if (new_i_size
> inode
->i_size
)
1841 i_size_write(inode
, pos
+copied
);
1842 ext4_set_inode_state(inode
, EXT4_STATE_JDATA
);
1843 if (new_i_size
> EXT4_I(inode
)->i_disksize
) {
1844 ext4_update_i_disksize(inode
, new_i_size
);
1845 ret2
= ext4_mark_inode_dirty(handle
, inode
);
1851 page_cache_release(page
);
1852 if (pos
+ len
> inode
->i_size
&& ext4_can_truncate(inode
))
1853 /* if we have allocated more blocks and copied
1854 * less. We will have blocks allocated outside
1855 * inode->i_size. So truncate them
1857 ext4_orphan_add(handle
, inode
);
1859 ret2
= ext4_journal_stop(handle
);
1862 if (pos
+ len
> inode
->i_size
) {
1863 ext4_truncate_failed_write(inode
);
1865 * If truncate failed early the inode might still be
1866 * on the orphan list; we need to make sure the inode
1867 * is removed from the orphan list in that case.
1870 ext4_orphan_del(NULL
, inode
);
1873 return ret
? ret
: copied
;
1877 * Reserve a single block located at lblock
1879 static int ext4_da_reserve_space(struct inode
*inode
, sector_t lblock
)
1882 struct ext4_sb_info
*sbi
= EXT4_SB(inode
->i_sb
);
1883 struct ext4_inode_info
*ei
= EXT4_I(inode
);
1884 unsigned long md_needed
;
1888 * recalculate the amount of metadata blocks to reserve
1889 * in order to allocate nrblocks
1890 * worse case is one extent per block
1893 spin_lock(&ei
->i_block_reservation_lock
);
1894 md_needed
= ext4_calc_metadata_amount(inode
, lblock
);
1895 trace_ext4_da_reserve_space(inode
, md_needed
);
1896 spin_unlock(&ei
->i_block_reservation_lock
);
1899 * We will charge metadata quota at writeout time; this saves
1900 * us from metadata over-estimation, though we may go over by
1901 * a small amount in the end. Here we just reserve for data.
1903 ret
= dquot_reserve_block(inode
, 1);
1907 * We do still charge estimated metadata to the sb though;
1908 * we cannot afford to run out of free blocks.
1910 if (ext4_claim_free_blocks(sbi
, md_needed
+ 1)) {
1911 dquot_release_reservation_block(inode
, 1);
1912 if (ext4_should_retry_alloc(inode
->i_sb
, &retries
)) {
1918 spin_lock(&ei
->i_block_reservation_lock
);
1919 ei
->i_reserved_data_blocks
++;
1920 ei
->i_reserved_meta_blocks
+= md_needed
;
1921 spin_unlock(&ei
->i_block_reservation_lock
);
1923 return 0; /* success */
1926 static void ext4_da_release_space(struct inode
*inode
, int to_free
)
1928 struct ext4_sb_info
*sbi
= EXT4_SB(inode
->i_sb
);
1929 struct ext4_inode_info
*ei
= EXT4_I(inode
);
1932 return; /* Nothing to release, exit */
1934 spin_lock(&EXT4_I(inode
)->i_block_reservation_lock
);
1936 trace_ext4_da_release_space(inode
, to_free
);
1937 if (unlikely(to_free
> ei
->i_reserved_data_blocks
)) {
1939 * if there aren't enough reserved blocks, then the
1940 * counter is messed up somewhere. Since this
1941 * function is called from invalidate page, it's
1942 * harmless to return without any action.
1944 ext4_msg(inode
->i_sb
, KERN_NOTICE
, "ext4_da_release_space: "
1945 "ino %lu, to_free %d with only %d reserved "
1946 "data blocks\n", inode
->i_ino
, to_free
,
1947 ei
->i_reserved_data_blocks
);
1949 to_free
= ei
->i_reserved_data_blocks
;
1951 ei
->i_reserved_data_blocks
-= to_free
;
1953 if (ei
->i_reserved_data_blocks
== 0) {
1955 * We can release all of the reserved metadata blocks
1956 * only when we have written all of the delayed
1957 * allocation blocks.
1959 percpu_counter_sub(&sbi
->s_dirtyblocks_counter
,
1960 ei
->i_reserved_meta_blocks
);
1961 ei
->i_reserved_meta_blocks
= 0;
1962 ei
->i_da_metadata_calc_len
= 0;
1965 /* update fs dirty data blocks counter */
1966 percpu_counter_sub(&sbi
->s_dirtyblocks_counter
, to_free
);
1968 spin_unlock(&EXT4_I(inode
)->i_block_reservation_lock
);
1970 dquot_release_reservation_block(inode
, to_free
);
1973 static void ext4_da_page_release_reservation(struct page
*page
,
1974 unsigned long offset
)
1977 struct buffer_head
*head
, *bh
;
1978 unsigned int curr_off
= 0;
1980 head
= page_buffers(page
);
1983 unsigned int next_off
= curr_off
+ bh
->b_size
;
1985 if ((offset
<= curr_off
) && (buffer_delay(bh
))) {
1987 clear_buffer_delay(bh
);
1989 curr_off
= next_off
;
1990 } while ((bh
= bh
->b_this_page
) != head
);
1991 ext4_da_release_space(page
->mapping
->host
, to_release
);
1995 * Delayed allocation stuff
1999 * mpage_da_submit_io - walks through extent of pages and try to write
2000 * them with writepage() call back
2002 * @mpd->inode: inode
2003 * @mpd->first_page: first page of the extent
2004 * @mpd->next_page: page after the last page of the extent
2006 * By the time mpage_da_submit_io() is called we expect all blocks
2007 * to be allocated. this may be wrong if allocation failed.
2009 * As pages are already locked by write_cache_pages(), we can't use it
2011 static int mpage_da_submit_io(struct mpage_da_data
*mpd
,
2012 struct ext4_map_blocks
*map
)
2014 struct pagevec pvec
;
2015 unsigned long index
, end
;
2016 int ret
= 0, err
, nr_pages
, i
;
2017 struct inode
*inode
= mpd
->inode
;
2018 struct address_space
*mapping
= inode
->i_mapping
;
2019 loff_t size
= i_size_read(inode
);
2020 unsigned int len
, block_start
;
2021 struct buffer_head
*bh
, *page_bufs
= NULL
;
2022 int journal_data
= ext4_should_journal_data(inode
);
2023 sector_t pblock
= 0, cur_logical
= 0;
2024 struct ext4_io_submit io_submit
;
2026 BUG_ON(mpd
->next_page
<= mpd
->first_page
);
2027 memset(&io_submit
, 0, sizeof(io_submit
));
2029 * We need to start from the first_page to the next_page - 1
2030 * to make sure we also write the mapped dirty buffer_heads.
2031 * If we look at mpd->b_blocknr we would only be looking
2032 * at the currently mapped buffer_heads.
2034 index
= mpd
->first_page
;
2035 end
= mpd
->next_page
- 1;
2037 pagevec_init(&pvec
, 0);
2038 while (index
<= end
) {
2039 nr_pages
= pagevec_lookup(&pvec
, mapping
, index
, PAGEVEC_SIZE
);
2042 for (i
= 0; i
< nr_pages
; i
++) {
2043 int commit_write
= 0, redirty_page
= 0;
2044 struct page
*page
= pvec
.pages
[i
];
2046 index
= page
->index
;
2050 if (index
== size
>> PAGE_CACHE_SHIFT
)
2051 len
= size
& ~PAGE_CACHE_MASK
;
2053 len
= PAGE_CACHE_SIZE
;
2055 cur_logical
= index
<< (PAGE_CACHE_SHIFT
-
2057 pblock
= map
->m_pblk
+ (cur_logical
-
2062 BUG_ON(!PageLocked(page
));
2063 BUG_ON(PageWriteback(page
));
2066 * If the page does not have buffers (for
2067 * whatever reason), try to create them using
2068 * block_prepare_write. If this fails,
2069 * redirty the page and move on.
2071 if (!page_has_buffers(page
)) {
2072 if (block_prepare_write(page
, 0, len
,
2073 noalloc_get_block_write
)) {
2075 redirty_page_for_writepage(mpd
->wbc
,
2083 bh
= page_bufs
= page_buffers(page
);
2088 if (map
&& (cur_logical
>= map
->m_lblk
) &&
2089 (cur_logical
<= (map
->m_lblk
+
2090 (map
->m_len
- 1)))) {
2091 if (buffer_delay(bh
)) {
2092 clear_buffer_delay(bh
);
2093 bh
->b_blocknr
= pblock
;
2095 if (buffer_unwritten(bh
) ||
2097 BUG_ON(bh
->b_blocknr
!= pblock
);
2098 if (map
->m_flags
& EXT4_MAP_UNINIT
)
2099 set_buffer_uninit(bh
);
2100 clear_buffer_unwritten(bh
);
2103 /* redirty page if block allocation undone */
2104 if (buffer_delay(bh
) || buffer_unwritten(bh
))
2106 bh
= bh
->b_this_page
;
2107 block_start
+= bh
->b_size
;
2110 } while (bh
!= page_bufs
);
2116 /* mark the buffer_heads as dirty & uptodate */
2117 block_commit_write(page
, 0, len
);
2120 * Delalloc doesn't support data journalling,
2121 * but eventually maybe we'll lift this
2124 if (unlikely(journal_data
&& PageChecked(page
)))
2125 err
= __ext4_journalled_writepage(page
, len
);
2127 err
= ext4_bio_write_page(&io_submit
, page
,
2131 mpd
->pages_written
++;
2133 * In error case, we have to continue because
2134 * remaining pages are still locked
2139 pagevec_release(&pvec
);
2141 ext4_io_submit(&io_submit
);
2145 static void ext4_da_block_invalidatepages(struct mpage_da_data
*mpd
,
2146 sector_t logical
, long blk_cnt
)
2150 struct pagevec pvec
;
2151 struct inode
*inode
= mpd
->inode
;
2152 struct address_space
*mapping
= inode
->i_mapping
;
2154 index
= logical
>> (PAGE_CACHE_SHIFT
- inode
->i_blkbits
);
2155 end
= (logical
+ blk_cnt
- 1) >>
2156 (PAGE_CACHE_SHIFT
- inode
->i_blkbits
);
2157 while (index
<= end
) {
2158 nr_pages
= pagevec_lookup(&pvec
, mapping
, index
, PAGEVEC_SIZE
);
2161 for (i
= 0; i
< nr_pages
; i
++) {
2162 struct page
*page
= pvec
.pages
[i
];
2163 if (page
->index
> end
)
2165 BUG_ON(!PageLocked(page
));
2166 BUG_ON(PageWriteback(page
));
2167 block_invalidatepage(page
, 0);
2168 ClearPageUptodate(page
);
2171 index
= pvec
.pages
[nr_pages
- 1]->index
+ 1;
2172 pagevec_release(&pvec
);
2177 static void ext4_print_free_blocks(struct inode
*inode
)
2179 struct ext4_sb_info
*sbi
= EXT4_SB(inode
->i_sb
);
2180 printk(KERN_CRIT
"Total free blocks count %lld\n",
2181 ext4_count_free_blocks(inode
->i_sb
));
2182 printk(KERN_CRIT
"Free/Dirty block details\n");
2183 printk(KERN_CRIT
"free_blocks=%lld\n",
2184 (long long) percpu_counter_sum(&sbi
->s_freeblocks_counter
));
2185 printk(KERN_CRIT
"dirty_blocks=%lld\n",
2186 (long long) percpu_counter_sum(&sbi
->s_dirtyblocks_counter
));
2187 printk(KERN_CRIT
"Block reservation details\n");
2188 printk(KERN_CRIT
"i_reserved_data_blocks=%u\n",
2189 EXT4_I(inode
)->i_reserved_data_blocks
);
2190 printk(KERN_CRIT
"i_reserved_meta_blocks=%u\n",
2191 EXT4_I(inode
)->i_reserved_meta_blocks
);
2196 * mpage_da_map_and_submit - go through given space, map them
2197 * if necessary, and then submit them for I/O
2199 * @mpd - bh describing space
2201 * The function skips space we know is already mapped to disk blocks.
2204 static void mpage_da_map_and_submit(struct mpage_da_data
*mpd
)
2206 int err
, blks
, get_blocks_flags
;
2207 struct ext4_map_blocks map
, *mapp
= NULL
;
2208 sector_t next
= mpd
->b_blocknr
;
2209 unsigned max_blocks
= mpd
->b_size
>> mpd
->inode
->i_blkbits
;
2210 loff_t disksize
= EXT4_I(mpd
->inode
)->i_disksize
;
2211 handle_t
*handle
= NULL
;
2214 * If the blocks are mapped already, or we couldn't accumulate
2215 * any blocks, then proceed immediately to the submission stage.
2217 if ((mpd
->b_size
== 0) ||
2218 ((mpd
->b_state
& (1 << BH_Mapped
)) &&
2219 !(mpd
->b_state
& (1 << BH_Delay
)) &&
2220 !(mpd
->b_state
& (1 << BH_Unwritten
))))
2223 handle
= ext4_journal_current_handle();
2227 * Call ext4_map_blocks() to allocate any delayed allocation
2228 * blocks, or to convert an uninitialized extent to be
2229 * initialized (in the case where we have written into
2230 * one or more preallocated blocks).
2232 * We pass in the magic EXT4_GET_BLOCKS_DELALLOC_RESERVE to
2233 * indicate that we are on the delayed allocation path. This
2234 * affects functions in many different parts of the allocation
2235 * call path. This flag exists primarily because we don't
2236 * want to change *many* call functions, so ext4_map_blocks()
2237 * will set the magic i_delalloc_reserved_flag once the
2238 * inode's allocation semaphore is taken.
2240 * If the blocks in questions were delalloc blocks, set
2241 * EXT4_GET_BLOCKS_DELALLOC_RESERVE so the delalloc accounting
2242 * variables are updated after the blocks have been allocated.
2245 map
.m_len
= max_blocks
;
2246 get_blocks_flags
= EXT4_GET_BLOCKS_CREATE
;
2247 if (ext4_should_dioread_nolock(mpd
->inode
))
2248 get_blocks_flags
|= EXT4_GET_BLOCKS_IO_CREATE_EXT
;
2249 if (mpd
->b_state
& (1 << BH_Delay
))
2250 get_blocks_flags
|= EXT4_GET_BLOCKS_DELALLOC_RESERVE
;
2252 blks
= ext4_map_blocks(handle
, mpd
->inode
, &map
, get_blocks_flags
);
2254 struct super_block
*sb
= mpd
->inode
->i_sb
;
2258 * If get block returns EAGAIN or ENOSPC and there
2259 * appears to be free blocks we will call
2260 * ext4_writepage() for all of the pages which will
2261 * just redirty the pages.
2266 if (err
== -ENOSPC
&&
2267 ext4_count_free_blocks(sb
)) {
2273 * get block failure will cause us to loop in
2274 * writepages, because a_ops->writepage won't be able
2275 * to make progress. The page will be redirtied by
2276 * writepage and writepages will again try to write
2279 if (!(EXT4_SB(sb
)->s_mount_flags
& EXT4_MF_FS_ABORTED
)) {
2280 ext4_msg(sb
, KERN_CRIT
,
2281 "delayed block allocation failed for inode %lu "
2282 "at logical offset %llu with max blocks %zd "
2283 "with error %d", mpd
->inode
->i_ino
,
2284 (unsigned long long) next
,
2285 mpd
->b_size
>> mpd
->inode
->i_blkbits
, err
);
2286 ext4_msg(sb
, KERN_CRIT
,
2287 "This should not happen!! Data will be lost\n");
2289 ext4_print_free_blocks(mpd
->inode
);
2291 /* invalidate all the pages */
2292 ext4_da_block_invalidatepages(mpd
, next
,
2293 mpd
->b_size
>> mpd
->inode
->i_blkbits
);
2299 if (map
.m_flags
& EXT4_MAP_NEW
) {
2300 struct block_device
*bdev
= mpd
->inode
->i_sb
->s_bdev
;
2303 for (i
= 0; i
< map
.m_len
; i
++)
2304 unmap_underlying_metadata(bdev
, map
.m_pblk
+ i
);
2307 if (ext4_should_order_data(mpd
->inode
)) {
2308 err
= ext4_jbd2_file_inode(handle
, mpd
->inode
);
2310 /* This only happens if the journal is aborted */
2315 * Update on-disk size along with block allocation.
2317 disksize
= ((loff_t
) next
+ blks
) << mpd
->inode
->i_blkbits
;
2318 if (disksize
> i_size_read(mpd
->inode
))
2319 disksize
= i_size_read(mpd
->inode
);
2320 if (disksize
> EXT4_I(mpd
->inode
)->i_disksize
) {
2321 ext4_update_i_disksize(mpd
->inode
, disksize
);
2322 err
= ext4_mark_inode_dirty(handle
, mpd
->inode
);
2324 ext4_error(mpd
->inode
->i_sb
,
2325 "Failed to mark inode %lu dirty",
2330 mpage_da_submit_io(mpd
, mapp
);
2334 #define BH_FLAGS ((1 << BH_Uptodate) | (1 << BH_Mapped) | \
2335 (1 << BH_Delay) | (1 << BH_Unwritten))
2338 * mpage_add_bh_to_extent - try to add one more block to extent of blocks
2340 * @mpd->lbh - extent of blocks
2341 * @logical - logical number of the block in the file
2342 * @bh - bh of the block (used to access block's state)
2344 * the function is used to collect contig. blocks in same state
2346 static void mpage_add_bh_to_extent(struct mpage_da_data
*mpd
,
2347 sector_t logical
, size_t b_size
,
2348 unsigned long b_state
)
2351 int nrblocks
= mpd
->b_size
>> mpd
->inode
->i_blkbits
;
2354 * XXX Don't go larger than mballoc is willing to allocate
2355 * This is a stopgap solution. We eventually need to fold
2356 * mpage_da_submit_io() into this function and then call
2357 * ext4_map_blocks() multiple times in a loop
2359 if (nrblocks
>= 8*1024*1024/mpd
->inode
->i_sb
->s_blocksize
)
2362 /* check if thereserved journal credits might overflow */
2363 if (!(ext4_test_inode_flag(mpd
->inode
, EXT4_INODE_EXTENTS
))) {
2364 if (nrblocks
>= EXT4_MAX_TRANS_DATA
) {
2366 * With non-extent format we are limited by the journal
2367 * credit available. Total credit needed to insert
2368 * nrblocks contiguous blocks is dependent on the
2369 * nrblocks. So limit nrblocks.
2372 } else if ((nrblocks
+ (b_size
>> mpd
->inode
->i_blkbits
)) >
2373 EXT4_MAX_TRANS_DATA
) {
2375 * Adding the new buffer_head would make it cross the
2376 * allowed limit for which we have journal credit
2377 * reserved. So limit the new bh->b_size
2379 b_size
= (EXT4_MAX_TRANS_DATA
- nrblocks
) <<
2380 mpd
->inode
->i_blkbits
;
2381 /* we will do mpage_da_submit_io in the next loop */
2385 * First block in the extent
2387 if (mpd
->b_size
== 0) {
2388 mpd
->b_blocknr
= logical
;
2389 mpd
->b_size
= b_size
;
2390 mpd
->b_state
= b_state
& BH_FLAGS
;
2394 next
= mpd
->b_blocknr
+ nrblocks
;
2396 * Can we merge the block to our big extent?
2398 if (logical
== next
&& (b_state
& BH_FLAGS
) == mpd
->b_state
) {
2399 mpd
->b_size
+= b_size
;
2405 * We couldn't merge the block to our extent, so we
2406 * need to flush current extent and start new one
2408 mpage_da_map_and_submit(mpd
);
2412 static int ext4_bh_delay_or_unwritten(handle_t
*handle
, struct buffer_head
*bh
)
2414 return (buffer_delay(bh
) || buffer_unwritten(bh
)) && buffer_dirty(bh
);
2418 * __mpage_da_writepage - finds extent of pages and blocks
2420 * @page: page to consider
2421 * @wbc: not used, we just follow rules
2424 * The function finds extents of pages and scan them for all blocks.
2426 static int __mpage_da_writepage(struct page
*page
,
2427 struct writeback_control
*wbc
,
2428 struct mpage_da_data
*mpd
)
2430 struct inode
*inode
= mpd
->inode
;
2431 struct buffer_head
*bh
, *head
;
2435 * Can we merge this page to current extent?
2437 if (mpd
->next_page
!= page
->index
) {
2439 * Nope, we can't. So, we map non-allocated blocks
2440 * and start IO on them
2442 if (mpd
->next_page
!= mpd
->first_page
) {
2443 mpage_da_map_and_submit(mpd
);
2445 * skip rest of the page in the page_vec
2447 redirty_page_for_writepage(wbc
, page
);
2449 return MPAGE_DA_EXTENT_TAIL
;
2453 * Start next extent of pages ...
2455 mpd
->first_page
= page
->index
;
2465 mpd
->next_page
= page
->index
+ 1;
2466 logical
= (sector_t
) page
->index
<<
2467 (PAGE_CACHE_SHIFT
- inode
->i_blkbits
);
2469 if (!page_has_buffers(page
)) {
2470 mpage_add_bh_to_extent(mpd
, logical
, PAGE_CACHE_SIZE
,
2471 (1 << BH_Dirty
) | (1 << BH_Uptodate
));
2473 return MPAGE_DA_EXTENT_TAIL
;
2476 * Page with regular buffer heads, just add all dirty ones
2478 head
= page_buffers(page
);
2481 BUG_ON(buffer_locked(bh
));
2483 * We need to try to allocate
2484 * unmapped blocks in the same page.
2485 * Otherwise we won't make progress
2486 * with the page in ext4_writepage
2488 if (ext4_bh_delay_or_unwritten(NULL
, bh
)) {
2489 mpage_add_bh_to_extent(mpd
, logical
,
2493 return MPAGE_DA_EXTENT_TAIL
;
2494 } else if (buffer_dirty(bh
) && (buffer_mapped(bh
))) {
2496 * mapped dirty buffer. We need to update
2497 * the b_state because we look at
2498 * b_state in mpage_da_map_blocks. We don't
2499 * update b_size because if we find an
2500 * unmapped buffer_head later we need to
2501 * use the b_state flag of that buffer_head.
2503 if (mpd
->b_size
== 0)
2504 mpd
->b_state
= bh
->b_state
& BH_FLAGS
;
2507 } while ((bh
= bh
->b_this_page
) != head
);
2514 * This is a special get_blocks_t callback which is used by
2515 * ext4_da_write_begin(). It will either return mapped block or
2516 * reserve space for a single block.
2518 * For delayed buffer_head we have BH_Mapped, BH_New, BH_Delay set.
2519 * We also have b_blocknr = -1 and b_bdev initialized properly
2521 * For unwritten buffer_head we have BH_Mapped, BH_New, BH_Unwritten set.
2522 * We also have b_blocknr = physicalblock mapping unwritten extent and b_bdev
2523 * initialized properly.
2525 static int ext4_da_get_block_prep(struct inode
*inode
, sector_t iblock
,
2526 struct buffer_head
*bh
, int create
)
2528 struct ext4_map_blocks map
;
2530 sector_t invalid_block
= ~((sector_t
) 0xffff);
2532 if (invalid_block
< ext4_blocks_count(EXT4_SB(inode
->i_sb
)->s_es
))
2535 BUG_ON(create
== 0);
2536 BUG_ON(bh
->b_size
!= inode
->i_sb
->s_blocksize
);
2538 map
.m_lblk
= iblock
;
2542 * first, we need to know whether the block is allocated already
2543 * preallocated blocks are unmapped but should treated
2544 * the same as allocated blocks.
2546 ret
= ext4_map_blocks(NULL
, inode
, &map
, 0);
2550 if (buffer_delay(bh
))
2551 return 0; /* Not sure this could or should happen */
2553 * XXX: __block_prepare_write() unmaps passed block,
2556 ret
= ext4_da_reserve_space(inode
, iblock
);
2558 /* not enough space to reserve */
2561 map_bh(bh
, inode
->i_sb
, invalid_block
);
2563 set_buffer_delay(bh
);
2567 map_bh(bh
, inode
->i_sb
, map
.m_pblk
);
2568 bh
->b_state
= (bh
->b_state
& ~EXT4_MAP_FLAGS
) | map
.m_flags
;
2570 if (buffer_unwritten(bh
)) {
2571 /* A delayed write to unwritten bh should be marked
2572 * new and mapped. Mapped ensures that we don't do
2573 * get_block multiple times when we write to the same
2574 * offset and new ensures that we do proper zero out
2575 * for partial write.
2578 set_buffer_mapped(bh
);
2584 * This function is used as a standard get_block_t calback function
2585 * when there is no desire to allocate any blocks. It is used as a
2586 * callback function for block_prepare_write() and block_write_full_page().
2587 * These functions should only try to map a single block at a time.
2589 * Since this function doesn't do block allocations even if the caller
2590 * requests it by passing in create=1, it is critically important that
2591 * any caller checks to make sure that any buffer heads are returned
2592 * by this function are either all already mapped or marked for
2593 * delayed allocation before calling block_write_full_page(). Otherwise,
2594 * b_blocknr could be left unitialized, and the page write functions will
2595 * be taken by surprise.
2597 static int noalloc_get_block_write(struct inode
*inode
, sector_t iblock
,
2598 struct buffer_head
*bh_result
, int create
)
2600 BUG_ON(bh_result
->b_size
!= inode
->i_sb
->s_blocksize
);
2601 return _ext4_get_block(inode
, iblock
, bh_result
, 0);
2604 static int bget_one(handle_t
*handle
, struct buffer_head
*bh
)
2610 static int bput_one(handle_t
*handle
, struct buffer_head
*bh
)
2616 static int __ext4_journalled_writepage(struct page
*page
,
2619 struct address_space
*mapping
= page
->mapping
;
2620 struct inode
*inode
= mapping
->host
;
2621 struct buffer_head
*page_bufs
;
2622 handle_t
*handle
= NULL
;
2626 ClearPageChecked(page
);
2627 page_bufs
= page_buffers(page
);
2629 walk_page_buffers(handle
, page_bufs
, 0, len
, NULL
, bget_one
);
2630 /* As soon as we unlock the page, it can go away, but we have
2631 * references to buffers so we are safe */
2634 handle
= ext4_journal_start(inode
, ext4_writepage_trans_blocks(inode
));
2635 if (IS_ERR(handle
)) {
2636 ret
= PTR_ERR(handle
);
2640 ret
= walk_page_buffers(handle
, page_bufs
, 0, len
, NULL
,
2641 do_journal_get_write_access
);
2643 err
= walk_page_buffers(handle
, page_bufs
, 0, len
, NULL
,
2647 err
= ext4_journal_stop(handle
);
2651 walk_page_buffers(handle
, page_bufs
, 0, len
, NULL
, bput_one
);
2652 ext4_set_inode_state(inode
, EXT4_STATE_JDATA
);
2657 static int ext4_set_bh_endio(struct buffer_head
*bh
, struct inode
*inode
);
2658 static void ext4_end_io_buffer_write(struct buffer_head
*bh
, int uptodate
);
2661 * Note that we don't need to start a transaction unless we're journaling data
2662 * because we should have holes filled from ext4_page_mkwrite(). We even don't
2663 * need to file the inode to the transaction's list in ordered mode because if
2664 * we are writing back data added by write(), the inode is already there and if
2665 * we are writing back data modified via mmap(), noone guarantees in which
2666 * transaction the data will hit the disk. In case we are journaling data, we
2667 * cannot start transaction directly because transaction start ranks above page
2668 * lock so we have to do some magic.
2670 * This function can get called via...
2671 * - ext4_da_writepages after taking page lock (have journal handle)
2672 * - journal_submit_inode_data_buffers (no journal handle)
2673 * - shrink_page_list via pdflush (no journal handle)
2674 * - grab_page_cache when doing write_begin (have journal handle)
2676 * We don't do any block allocation in this function. If we have page with
2677 * multiple blocks we need to write those buffer_heads that are mapped. This
2678 * is important for mmaped based write. So if we do with blocksize 1K
2679 * truncate(f, 1024);
2680 * a = mmap(f, 0, 4096);
2682 * truncate(f, 4096);
2683 * we have in the page first buffer_head mapped via page_mkwrite call back
2684 * but other bufer_heads would be unmapped but dirty(dirty done via the
2685 * do_wp_page). So writepage should write the first block. If we modify
2686 * the mmap area beyond 1024 we will again get a page_fault and the
2687 * page_mkwrite callback will do the block allocation and mark the
2688 * buffer_heads mapped.
2690 * We redirty the page if we have any buffer_heads that is either delay or
2691 * unwritten in the page.
2693 * We can get recursively called as show below.
2695 * ext4_writepage() -> kmalloc() -> __alloc_pages() -> page_launder() ->
2698 * But since we don't do any block allocation we should not deadlock.
2699 * Page also have the dirty flag cleared so we don't get recurive page_lock.
2701 static int ext4_writepage(struct page
*page
,
2702 struct writeback_control
*wbc
)
2704 int ret
= 0, commit_write
= 0;
2707 struct buffer_head
*page_bufs
= NULL
;
2708 struct inode
*inode
= page
->mapping
->host
;
2710 trace_ext4_writepage(inode
, page
);
2711 size
= i_size_read(inode
);
2712 if (page
->index
== size
>> PAGE_CACHE_SHIFT
)
2713 len
= size
& ~PAGE_CACHE_MASK
;
2715 len
= PAGE_CACHE_SIZE
;
2718 * If the page does not have buffers (for whatever reason),
2719 * try to create them using block_prepare_write. If this
2720 * fails, redirty the page and move on.
2722 if (!page_buffers(page
)) {
2723 if (block_prepare_write(page
, 0, len
,
2724 noalloc_get_block_write
)) {
2726 redirty_page_for_writepage(wbc
, page
);
2732 page_bufs
= page_buffers(page
);
2733 if (walk_page_buffers(NULL
, page_bufs
, 0, len
, NULL
,
2734 ext4_bh_delay_or_unwritten
)) {
2736 * We don't want to do block allocation So redirty the
2737 * page and return We may reach here when we do a
2738 * journal commit via
2739 * journal_submit_inode_data_buffers. If we don't
2740 * have mapping block we just ignore them. We can also
2741 * reach here via shrink_page_list
2746 /* now mark the buffer_heads as dirty and uptodate */
2747 block_commit_write(page
, 0, len
);
2749 if (PageChecked(page
) && ext4_should_journal_data(inode
))
2751 * It's mmapped pagecache. Add buffers and journal it. There
2752 * doesn't seem much point in redirtying the page here.
2754 return __ext4_journalled_writepage(page
, len
);
2756 if (buffer_uninit(page_bufs
)) {
2757 ext4_set_bh_endio(page_bufs
, inode
);
2758 ret
= block_write_full_page_endio(page
, noalloc_get_block_write
,
2759 wbc
, ext4_end_io_buffer_write
);
2761 ret
= block_write_full_page(page
, noalloc_get_block_write
,
2768 * This is called via ext4_da_writepages() to
2769 * calulate the total number of credits to reserve to fit
2770 * a single extent allocation into a single transaction,
2771 * ext4_da_writpeages() will loop calling this before
2772 * the block allocation.
2775 static int ext4_da_writepages_trans_blocks(struct inode
*inode
)
2777 int max_blocks
= EXT4_I(inode
)->i_reserved_data_blocks
;
2780 * With non-extent format the journal credit needed to
2781 * insert nrblocks contiguous block is dependent on
2782 * number of contiguous block. So we will limit
2783 * number of contiguous block to a sane value
2785 if (!(ext4_test_inode_flag(inode
, EXT4_INODE_EXTENTS
)) &&
2786 (max_blocks
> EXT4_MAX_TRANS_DATA
))
2787 max_blocks
= EXT4_MAX_TRANS_DATA
;
2789 return ext4_chunk_trans_blocks(inode
, max_blocks
);
2793 * write_cache_pages_da - walk the list of dirty pages of the given
2794 * address space and call the callback function (which usually writes
2797 * This is a forked version of write_cache_pages(). Differences:
2798 * Range cyclic is ignored.
2799 * no_nrwrite_index_update is always presumed true
2801 static int write_cache_pages_da(struct address_space
*mapping
,
2802 struct writeback_control
*wbc
,
2803 struct mpage_da_data
*mpd
,
2804 pgoff_t
*done_index
)
2808 struct pagevec pvec
;
2811 pgoff_t end
; /* Inclusive */
2812 long nr_to_write
= wbc
->nr_to_write
;
2815 pagevec_init(&pvec
, 0);
2816 index
= wbc
->range_start
>> PAGE_CACHE_SHIFT
;
2817 end
= wbc
->range_end
>> PAGE_CACHE_SHIFT
;
2819 if (wbc
->sync_mode
== WB_SYNC_ALL
)
2820 tag
= PAGECACHE_TAG_TOWRITE
;
2822 tag
= PAGECACHE_TAG_DIRTY
;
2824 *done_index
= index
;
2825 while (!done
&& (index
<= end
)) {
2828 nr_pages
= pagevec_lookup_tag(&pvec
, mapping
, &index
, tag
,
2829 min(end
- index
, (pgoff_t
)PAGEVEC_SIZE
-1) + 1);
2833 for (i
= 0; i
< nr_pages
; i
++) {
2834 struct page
*page
= pvec
.pages
[i
];
2837 * At this point, the page may be truncated or
2838 * invalidated (changing page->mapping to NULL), or
2839 * even swizzled back from swapper_space to tmpfs file
2840 * mapping. However, page->index will not change
2841 * because we have a reference on the page.
2843 if (page
->index
> end
) {
2848 *done_index
= page
->index
+ 1;
2853 * Page truncated or invalidated. We can freely skip it
2854 * then, even for data integrity operations: the page
2855 * has disappeared concurrently, so there could be no
2856 * real expectation of this data interity operation
2857 * even if there is now a new, dirty page at the same
2858 * pagecache address.
2860 if (unlikely(page
->mapping
!= mapping
)) {
2866 if (!PageDirty(page
)) {
2867 /* someone wrote it for us */
2868 goto continue_unlock
;
2871 if (PageWriteback(page
)) {
2872 if (wbc
->sync_mode
!= WB_SYNC_NONE
)
2873 wait_on_page_writeback(page
);
2875 goto continue_unlock
;
2878 BUG_ON(PageWriteback(page
));
2879 if (!clear_page_dirty_for_io(page
))
2880 goto continue_unlock
;
2882 ret
= __mpage_da_writepage(page
, wbc
, mpd
);
2883 if (unlikely(ret
)) {
2884 if (ret
== AOP_WRITEPAGE_ACTIVATE
) {
2893 if (nr_to_write
> 0) {
2895 if (nr_to_write
== 0 &&
2896 wbc
->sync_mode
== WB_SYNC_NONE
) {
2898 * We stop writing back only if we are
2899 * not doing integrity sync. In case of
2900 * integrity sync we have to keep going
2901 * because someone may be concurrently
2902 * dirtying pages, and we might have
2903 * synced a lot of newly appeared dirty
2904 * pages, but have not synced all of the
2912 pagevec_release(&pvec
);
2919 static int ext4_da_writepages(struct address_space
*mapping
,
2920 struct writeback_control
*wbc
)
2923 int range_whole
= 0;
2924 handle_t
*handle
= NULL
;
2925 struct mpage_da_data mpd
;
2926 struct inode
*inode
= mapping
->host
;
2927 int pages_written
= 0;
2929 unsigned int max_pages
;
2930 int range_cyclic
, cycled
= 1, io_done
= 0;
2931 int needed_blocks
, ret
= 0;
2932 long desired_nr_to_write
, nr_to_writebump
= 0;
2933 loff_t range_start
= wbc
->range_start
;
2934 struct ext4_sb_info
*sbi
= EXT4_SB(mapping
->host
->i_sb
);
2935 pgoff_t done_index
= 0;
2938 trace_ext4_da_writepages(inode
, wbc
);
2941 * No pages to write? This is mainly a kludge to avoid starting
2942 * a transaction for special inodes like journal inode on last iput()
2943 * because that could violate lock ordering on umount
2945 if (!mapping
->nrpages
|| !mapping_tagged(mapping
, PAGECACHE_TAG_DIRTY
))
2949 * If the filesystem has aborted, it is read-only, so return
2950 * right away instead of dumping stack traces later on that
2951 * will obscure the real source of the problem. We test
2952 * EXT4_MF_FS_ABORTED instead of sb->s_flag's MS_RDONLY because
2953 * the latter could be true if the filesystem is mounted
2954 * read-only, and in that case, ext4_da_writepages should
2955 * *never* be called, so if that ever happens, we would want
2958 if (unlikely(sbi
->s_mount_flags
& EXT4_MF_FS_ABORTED
))
2961 if (wbc
->range_start
== 0 && wbc
->range_end
== LLONG_MAX
)
2964 range_cyclic
= wbc
->range_cyclic
;
2965 if (wbc
->range_cyclic
) {
2966 index
= mapping
->writeback_index
;
2969 wbc
->range_start
= index
<< PAGE_CACHE_SHIFT
;
2970 wbc
->range_end
= LLONG_MAX
;
2971 wbc
->range_cyclic
= 0;
2974 index
= wbc
->range_start
>> PAGE_CACHE_SHIFT
;
2975 end
= wbc
->range_end
>> PAGE_CACHE_SHIFT
;
2979 * This works around two forms of stupidity. The first is in
2980 * the writeback code, which caps the maximum number of pages
2981 * written to be 1024 pages. This is wrong on multiple
2982 * levels; different architectues have a different page size,
2983 * which changes the maximum amount of data which gets
2984 * written. Secondly, 4 megabytes is way too small. XFS
2985 * forces this value to be 16 megabytes by multiplying
2986 * nr_to_write parameter by four, and then relies on its
2987 * allocator to allocate larger extents to make them
2988 * contiguous. Unfortunately this brings us to the second
2989 * stupidity, which is that ext4's mballoc code only allocates
2990 * at most 2048 blocks. So we force contiguous writes up to
2991 * the number of dirty blocks in the inode, or
2992 * sbi->max_writeback_mb_bump whichever is smaller.
2994 max_pages
= sbi
->s_max_writeback_mb_bump
<< (20 - PAGE_CACHE_SHIFT
);
2995 if (!range_cyclic
&& range_whole
) {
2996 if (wbc
->nr_to_write
== LONG_MAX
)
2997 desired_nr_to_write
= wbc
->nr_to_write
;
2999 desired_nr_to_write
= wbc
->nr_to_write
* 8;
3001 desired_nr_to_write
= ext4_num_dirty_pages(inode
, index
,
3003 if (desired_nr_to_write
> max_pages
)
3004 desired_nr_to_write
= max_pages
;
3006 if (wbc
->nr_to_write
< desired_nr_to_write
) {
3007 nr_to_writebump
= desired_nr_to_write
- wbc
->nr_to_write
;
3008 wbc
->nr_to_write
= desired_nr_to_write
;
3012 mpd
.inode
= mapping
->host
;
3014 pages_skipped
= wbc
->pages_skipped
;
3017 if (wbc
->sync_mode
== WB_SYNC_ALL
)
3018 tag_pages_for_writeback(mapping
, index
, end
);
3020 while (!ret
&& wbc
->nr_to_write
> 0) {
3023 * we insert one extent at a time. So we need
3024 * credit needed for single extent allocation.
3025 * journalled mode is currently not supported
3028 BUG_ON(ext4_should_journal_data(inode
));
3029 needed_blocks
= ext4_da_writepages_trans_blocks(inode
);
3031 /* start a new transaction*/
3032 handle
= ext4_journal_start(inode
, needed_blocks
);
3033 if (IS_ERR(handle
)) {
3034 ret
= PTR_ERR(handle
);
3035 ext4_msg(inode
->i_sb
, KERN_CRIT
, "%s: jbd2_start: "
3036 "%ld pages, ino %lu; err %d", __func__
,
3037 wbc
->nr_to_write
, inode
->i_ino
, ret
);
3038 goto out_writepages
;
3042 * Now call __mpage_da_writepage to find the next
3043 * contiguous region of logical blocks that need
3044 * blocks to be allocated by ext4. We don't actually
3045 * submit the blocks for I/O here, even though
3046 * write_cache_pages thinks it will, and will set the
3047 * pages as clean for write before calling
3048 * __mpage_da_writepage().
3056 mpd
.pages_written
= 0;
3058 ret
= write_cache_pages_da(mapping
, wbc
, &mpd
, &done_index
);
3060 * If we have a contiguous extent of pages and we
3061 * haven't done the I/O yet, map the blocks and submit
3064 if (!mpd
.io_done
&& mpd
.next_page
!= mpd
.first_page
) {
3065 mpage_da_map_and_submit(&mpd
);
3066 ret
= MPAGE_DA_EXTENT_TAIL
;
3068 trace_ext4_da_write_pages(inode
, &mpd
);
3069 wbc
->nr_to_write
-= mpd
.pages_written
;
3071 ext4_journal_stop(handle
);
3073 if ((mpd
.retval
== -ENOSPC
) && sbi
->s_journal
) {
3074 /* commit the transaction which would
3075 * free blocks released in the transaction
3078 jbd2_journal_force_commit_nested(sbi
->s_journal
);
3079 wbc
->pages_skipped
= pages_skipped
;
3081 } else if (ret
== MPAGE_DA_EXTENT_TAIL
) {
3083 * got one extent now try with
3086 pages_written
+= mpd
.pages_written
;
3087 wbc
->pages_skipped
= pages_skipped
;
3090 } else if (wbc
->nr_to_write
)
3092 * There is no more writeout needed
3093 * or we requested for a noblocking writeout
3094 * and we found the device congested
3098 if (!io_done
&& !cycled
) {
3101 wbc
->range_start
= index
<< PAGE_CACHE_SHIFT
;
3102 wbc
->range_end
= mapping
->writeback_index
- 1;
3105 if (pages_skipped
!= wbc
->pages_skipped
)
3106 ext4_msg(inode
->i_sb
, KERN_CRIT
,
3107 "This should not happen leaving %s "
3108 "with nr_to_write = %ld ret = %d",
3109 __func__
, wbc
->nr_to_write
, ret
);
3112 wbc
->range_cyclic
= range_cyclic
;
3113 if (wbc
->range_cyclic
|| (range_whole
&& wbc
->nr_to_write
> 0))
3115 * set the writeback_index so that range_cyclic
3116 * mode will write it back later
3118 mapping
->writeback_index
= done_index
;
3121 wbc
->nr_to_write
-= nr_to_writebump
;
3122 wbc
->range_start
= range_start
;
3123 trace_ext4_da_writepages_result(inode
, wbc
, ret
, pages_written
);
3127 #define FALL_BACK_TO_NONDELALLOC 1
3128 static int ext4_nonda_switch(struct super_block
*sb
)
3130 s64 free_blocks
, dirty_blocks
;
3131 struct ext4_sb_info
*sbi
= EXT4_SB(sb
);
3134 * switch to non delalloc mode if we are running low
3135 * on free block. The free block accounting via percpu
3136 * counters can get slightly wrong with percpu_counter_batch getting
3137 * accumulated on each CPU without updating global counters
3138 * Delalloc need an accurate free block accounting. So switch
3139 * to non delalloc when we are near to error range.
3141 free_blocks
= percpu_counter_read_positive(&sbi
->s_freeblocks_counter
);
3142 dirty_blocks
= percpu_counter_read_positive(&sbi
->s_dirtyblocks_counter
);
3143 if (2 * free_blocks
< 3 * dirty_blocks
||
3144 free_blocks
< (dirty_blocks
+ EXT4_FREEBLOCKS_WATERMARK
)) {
3146 * free block count is less than 150% of dirty blocks
3147 * or free blocks is less than watermark
3152 * Even if we don't switch but are nearing capacity,
3153 * start pushing delalloc when 1/2 of free blocks are dirty.
3155 if (free_blocks
< 2 * dirty_blocks
)
3156 writeback_inodes_sb_if_idle(sb
);
3161 static int ext4_da_write_begin(struct file
*file
, struct address_space
*mapping
,
3162 loff_t pos
, unsigned len
, unsigned flags
,
3163 struct page
**pagep
, void **fsdata
)
3165 int ret
, retries
= 0;
3168 struct inode
*inode
= mapping
->host
;
3171 index
= pos
>> PAGE_CACHE_SHIFT
;
3173 if (ext4_nonda_switch(inode
->i_sb
)) {
3174 *fsdata
= (void *)FALL_BACK_TO_NONDELALLOC
;
3175 return ext4_write_begin(file
, mapping
, pos
,
3176 len
, flags
, pagep
, fsdata
);
3178 *fsdata
= (void *)0;
3179 trace_ext4_da_write_begin(inode
, pos
, len
, flags
);
3182 * With delayed allocation, we don't log the i_disksize update
3183 * if there is delayed block allocation. But we still need
3184 * to journalling the i_disksize update if writes to the end
3185 * of file which has an already mapped buffer.
3187 handle
= ext4_journal_start(inode
, 1);
3188 if (IS_ERR(handle
)) {
3189 ret
= PTR_ERR(handle
);
3192 /* We cannot recurse into the filesystem as the transaction is already
3194 flags
|= AOP_FLAG_NOFS
;
3196 page
= grab_cache_page_write_begin(mapping
, index
, flags
);
3198 ext4_journal_stop(handle
);
3204 ret
= __block_write_begin(page
, pos
, len
, ext4_da_get_block_prep
);
3207 ext4_journal_stop(handle
);
3208 page_cache_release(page
);
3210 * block_write_begin may have instantiated a few blocks
3211 * outside i_size. Trim these off again. Don't need
3212 * i_size_read because we hold i_mutex.
3214 if (pos
+ len
> inode
->i_size
)
3215 ext4_truncate_failed_write(inode
);
3218 if (ret
== -ENOSPC
&& ext4_should_retry_alloc(inode
->i_sb
, &retries
))
3225 * Check if we should update i_disksize
3226 * when write to the end of file but not require block allocation
3228 static int ext4_da_should_update_i_disksize(struct page
*page
,
3229 unsigned long offset
)
3231 struct buffer_head
*bh
;
3232 struct inode
*inode
= page
->mapping
->host
;
3236 bh
= page_buffers(page
);
3237 idx
= offset
>> inode
->i_blkbits
;
3239 for (i
= 0; i
< idx
; i
++)
3240 bh
= bh
->b_this_page
;
3242 if (!buffer_mapped(bh
) || (buffer_delay(bh
)) || buffer_unwritten(bh
))
3247 static int ext4_da_write_end(struct file
*file
,
3248 struct address_space
*mapping
,
3249 loff_t pos
, unsigned len
, unsigned copied
,
3250 struct page
*page
, void *fsdata
)
3252 struct inode
*inode
= mapping
->host
;
3254 handle_t
*handle
= ext4_journal_current_handle();
3256 unsigned long start
, end
;
3257 int write_mode
= (int)(unsigned long)fsdata
;
3259 if (write_mode
== FALL_BACK_TO_NONDELALLOC
) {
3260 if (ext4_should_order_data(inode
)) {
3261 return ext4_ordered_write_end(file
, mapping
, pos
,
3262 len
, copied
, page
, fsdata
);
3263 } else if (ext4_should_writeback_data(inode
)) {
3264 return ext4_writeback_write_end(file
, mapping
, pos
,
3265 len
, copied
, page
, fsdata
);
3271 trace_ext4_da_write_end(inode
, pos
, len
, copied
);
3272 start
= pos
& (PAGE_CACHE_SIZE
- 1);
3273 end
= start
+ copied
- 1;
3276 * generic_write_end() will run mark_inode_dirty() if i_size
3277 * changes. So let's piggyback the i_disksize mark_inode_dirty
3281 new_i_size
= pos
+ copied
;
3282 if (new_i_size
> EXT4_I(inode
)->i_disksize
) {
3283 if (ext4_da_should_update_i_disksize(page
, end
)) {
3284 down_write(&EXT4_I(inode
)->i_data_sem
);
3285 if (new_i_size
> EXT4_I(inode
)->i_disksize
) {
3287 * Updating i_disksize when extending file
3288 * without needing block allocation
3290 if (ext4_should_order_data(inode
))
3291 ret
= ext4_jbd2_file_inode(handle
,
3294 EXT4_I(inode
)->i_disksize
= new_i_size
;
3296 up_write(&EXT4_I(inode
)->i_data_sem
);
3297 /* We need to mark inode dirty even if
3298 * new_i_size is less that inode->i_size
3299 * bu greater than i_disksize.(hint delalloc)
3301 ext4_mark_inode_dirty(handle
, inode
);
3304 ret2
= generic_write_end(file
, mapping
, pos
, len
, copied
,
3309 ret2
= ext4_journal_stop(handle
);
3313 return ret
? ret
: copied
;
3316 static void ext4_da_invalidatepage(struct page
*page
, unsigned long offset
)
3319 * Drop reserved blocks
3321 BUG_ON(!PageLocked(page
));
3322 if (!page_has_buffers(page
))
3325 ext4_da_page_release_reservation(page
, offset
);
3328 ext4_invalidatepage(page
, offset
);
3334 * Force all delayed allocation blocks to be allocated for a given inode.
3336 int ext4_alloc_da_blocks(struct inode
*inode
)
3338 trace_ext4_alloc_da_blocks(inode
);
3340 if (!EXT4_I(inode
)->i_reserved_data_blocks
&&
3341 !EXT4_I(inode
)->i_reserved_meta_blocks
)
3345 * We do something simple for now. The filemap_flush() will
3346 * also start triggering a write of the data blocks, which is
3347 * not strictly speaking necessary (and for users of
3348 * laptop_mode, not even desirable). However, to do otherwise
3349 * would require replicating code paths in:
3351 * ext4_da_writepages() ->
3352 * write_cache_pages() ---> (via passed in callback function)
3353 * __mpage_da_writepage() -->
3354 * mpage_add_bh_to_extent()
3355 * mpage_da_map_blocks()
3357 * The problem is that write_cache_pages(), located in
3358 * mm/page-writeback.c, marks pages clean in preparation for
3359 * doing I/O, which is not desirable if we're not planning on
3362 * We could call write_cache_pages(), and then redirty all of
3363 * the pages by calling redirty_page_for_writeback() but that
3364 * would be ugly in the extreme. So instead we would need to
3365 * replicate parts of the code in the above functions,
3366 * simplifying them becuase we wouldn't actually intend to
3367 * write out the pages, but rather only collect contiguous
3368 * logical block extents, call the multi-block allocator, and
3369 * then update the buffer heads with the block allocations.
3371 * For now, though, we'll cheat by calling filemap_flush(),
3372 * which will map the blocks, and start the I/O, but not
3373 * actually wait for the I/O to complete.
3375 return filemap_flush(inode
->i_mapping
);
3379 * bmap() is special. It gets used by applications such as lilo and by
3380 * the swapper to find the on-disk block of a specific piece of data.
3382 * Naturally, this is dangerous if the block concerned is still in the
3383 * journal. If somebody makes a swapfile on an ext4 data-journaling
3384 * filesystem and enables swap, then they may get a nasty shock when the
3385 * data getting swapped to that swapfile suddenly gets overwritten by
3386 * the original zero's written out previously to the journal and
3387 * awaiting writeback in the kernel's buffer cache.
3389 * So, if we see any bmap calls here on a modified, data-journaled file,
3390 * take extra steps to flush any blocks which might be in the cache.
3392 static sector_t
ext4_bmap(struct address_space
*mapping
, sector_t block
)
3394 struct inode
*inode
= mapping
->host
;
3398 if (mapping_tagged(mapping
, PAGECACHE_TAG_DIRTY
) &&
3399 test_opt(inode
->i_sb
, DELALLOC
)) {
3401 * With delalloc we want to sync the file
3402 * so that we can make sure we allocate
3405 filemap_write_and_wait(mapping
);
3408 if (EXT4_JOURNAL(inode
) &&
3409 ext4_test_inode_state(inode
, EXT4_STATE_JDATA
)) {
3411 * This is a REALLY heavyweight approach, but the use of
3412 * bmap on dirty files is expected to be extremely rare:
3413 * only if we run lilo or swapon on a freshly made file
3414 * do we expect this to happen.
3416 * (bmap requires CAP_SYS_RAWIO so this does not
3417 * represent an unprivileged user DOS attack --- we'd be
3418 * in trouble if mortal users could trigger this path at
3421 * NB. EXT4_STATE_JDATA is not set on files other than
3422 * regular files. If somebody wants to bmap a directory
3423 * or symlink and gets confused because the buffer
3424 * hasn't yet been flushed to disk, they deserve
3425 * everything they get.
3428 ext4_clear_inode_state(inode
, EXT4_STATE_JDATA
);
3429 journal
= EXT4_JOURNAL(inode
);
3430 jbd2_journal_lock_updates(journal
);
3431 err
= jbd2_journal_flush(journal
);
3432 jbd2_journal_unlock_updates(journal
);
3438 return generic_block_bmap(mapping
, block
, ext4_get_block
);
3441 static int ext4_readpage(struct file
*file
, struct page
*page
)
3443 return mpage_readpage(page
, ext4_get_block
);
3447 ext4_readpages(struct file
*file
, struct address_space
*mapping
,
3448 struct list_head
*pages
, unsigned nr_pages
)
3450 return mpage_readpages(mapping
, pages
, nr_pages
, ext4_get_block
);
3453 static void ext4_invalidatepage_free_endio(struct page
*page
, unsigned long offset
)
3455 struct buffer_head
*head
, *bh
;
3456 unsigned int curr_off
= 0;
3458 if (!page_has_buffers(page
))
3460 head
= bh
= page_buffers(page
);
3462 if (offset
<= curr_off
&& test_clear_buffer_uninit(bh
)
3464 ext4_free_io_end(bh
->b_private
);
3465 bh
->b_private
= NULL
;
3466 bh
->b_end_io
= NULL
;
3468 curr_off
= curr_off
+ bh
->b_size
;
3469 bh
= bh
->b_this_page
;
3470 } while (bh
!= head
);
3473 static void ext4_invalidatepage(struct page
*page
, unsigned long offset
)
3475 journal_t
*journal
= EXT4_JOURNAL(page
->mapping
->host
);
3478 * free any io_end structure allocated for buffers to be discarded
3480 if (ext4_should_dioread_nolock(page
->mapping
->host
))
3481 ext4_invalidatepage_free_endio(page
, offset
);
3483 * If it's a full truncate we just forget about the pending dirtying
3486 ClearPageChecked(page
);
3489 jbd2_journal_invalidatepage(journal
, page
, offset
);
3491 block_invalidatepage(page
, offset
);
3494 static int ext4_releasepage(struct page
*page
, gfp_t wait
)
3496 journal_t
*journal
= EXT4_JOURNAL(page
->mapping
->host
);
3498 WARN_ON(PageChecked(page
));
3499 if (!page_has_buffers(page
))
3502 return jbd2_journal_try_to_free_buffers(journal
, page
, wait
);
3504 return try_to_free_buffers(page
);
3508 * O_DIRECT for ext3 (or indirect map) based files
3510 * If the O_DIRECT write will extend the file then add this inode to the
3511 * orphan list. So recovery will truncate it back to the original size
3512 * if the machine crashes during the write.
3514 * If the O_DIRECT write is intantiating holes inside i_size and the machine
3515 * crashes then stale disk data _may_ be exposed inside the file. But current
3516 * VFS code falls back into buffered path in that case so we are safe.
3518 static ssize_t
ext4_ind_direct_IO(int rw
, struct kiocb
*iocb
,
3519 const struct iovec
*iov
, loff_t offset
,
3520 unsigned long nr_segs
)
3522 struct file
*file
= iocb
->ki_filp
;
3523 struct inode
*inode
= file
->f_mapping
->host
;
3524 struct ext4_inode_info
*ei
= EXT4_I(inode
);
3528 size_t count
= iov_length(iov
, nr_segs
);
3532 loff_t final_size
= offset
+ count
;
3534 if (final_size
> inode
->i_size
) {
3535 /* Credits for sb + inode write */
3536 handle
= ext4_journal_start(inode
, 2);
3537 if (IS_ERR(handle
)) {
3538 ret
= PTR_ERR(handle
);
3541 ret
= ext4_orphan_add(handle
, inode
);
3543 ext4_journal_stop(handle
);
3547 ei
->i_disksize
= inode
->i_size
;
3548 ext4_journal_stop(handle
);
3553 if (rw
== READ
&& ext4_should_dioread_nolock(inode
))
3554 ret
= __blockdev_direct_IO(rw
, iocb
, inode
,
3555 inode
->i_sb
->s_bdev
, iov
,
3557 ext4_get_block
, NULL
, NULL
, 0);
3559 ret
= blockdev_direct_IO(rw
, iocb
, inode
,
3560 inode
->i_sb
->s_bdev
, iov
,
3562 ext4_get_block
, NULL
);
3564 if (unlikely((rw
& WRITE
) && ret
< 0)) {
3565 loff_t isize
= i_size_read(inode
);
3566 loff_t end
= offset
+ iov_length(iov
, nr_segs
);
3569 vmtruncate(inode
, isize
);
3572 if (ret
== -ENOSPC
&& ext4_should_retry_alloc(inode
->i_sb
, &retries
))
3578 /* Credits for sb + inode write */
3579 handle
= ext4_journal_start(inode
, 2);
3580 if (IS_ERR(handle
)) {
3581 /* This is really bad luck. We've written the data
3582 * but cannot extend i_size. Bail out and pretend
3583 * the write failed... */
3584 ret
= PTR_ERR(handle
);
3586 ext4_orphan_del(NULL
, inode
);
3591 ext4_orphan_del(handle
, inode
);
3593 loff_t end
= offset
+ ret
;
3594 if (end
> inode
->i_size
) {
3595 ei
->i_disksize
= end
;
3596 i_size_write(inode
, end
);
3598 * We're going to return a positive `ret'
3599 * here due to non-zero-length I/O, so there's
3600 * no way of reporting error returns from
3601 * ext4_mark_inode_dirty() to userspace. So
3604 ext4_mark_inode_dirty(handle
, inode
);
3607 err
= ext4_journal_stop(handle
);
3616 * ext4_get_block used when preparing for a DIO write or buffer write.
3617 * We allocate an uinitialized extent if blocks haven't been allocated.
3618 * The extent will be converted to initialized after the IO is complete.
3620 static int ext4_get_block_write(struct inode
*inode
, sector_t iblock
,
3621 struct buffer_head
*bh_result
, int create
)
3623 ext4_debug("ext4_get_block_write: inode %lu, create flag %d\n",
3624 inode
->i_ino
, create
);
3625 return _ext4_get_block(inode
, iblock
, bh_result
,
3626 EXT4_GET_BLOCKS_IO_CREATE_EXT
);
3629 static void dump_completed_IO(struct inode
* inode
)
3632 struct list_head
*cur
, *before
, *after
;
3633 ext4_io_end_t
*io
, *io0
, *io1
;
3634 unsigned long flags
;
3636 if (list_empty(&EXT4_I(inode
)->i_completed_io_list
)){
3637 ext4_debug("inode %lu completed_io list is empty\n", inode
->i_ino
);
3641 ext4_debug("Dump inode %lu completed_io list \n", inode
->i_ino
);
3642 spin_lock_irqsave(&EXT4_I(inode
)->i_completed_io_lock
, flags
);
3643 list_for_each_entry(io
, &EXT4_I(inode
)->i_completed_io_list
, list
){
3646 io0
= container_of(before
, ext4_io_end_t
, list
);
3648 io1
= container_of(after
, ext4_io_end_t
, list
);
3650 ext4_debug("io 0x%p from inode %lu,prev 0x%p,next 0x%p\n",
3651 io
, inode
->i_ino
, io0
, io1
);
3653 spin_unlock_irqrestore(&EXT4_I(inode
)->i_completed_io_lock
, flags
);
3658 * This function is called from ext4_sync_file().
3660 * When IO is completed, the work to convert unwritten extents to
3661 * written is queued on workqueue but may not get immediately
3662 * scheduled. When fsync is called, we need to ensure the
3663 * conversion is complete before fsync returns.
3664 * The inode keeps track of a list of pending/completed IO that
3665 * might needs to do the conversion. This function walks through
3666 * the list and convert the related unwritten extents for completed IO
3668 * The function return the number of pending IOs on success.
3670 int flush_completed_IO(struct inode
*inode
)
3673 struct ext4_inode_info
*ei
= EXT4_I(inode
);
3674 unsigned long flags
;
3678 if (list_empty(&ei
->i_completed_io_list
))
3681 dump_completed_IO(inode
);
3682 spin_lock_irqsave(&ei
->i_completed_io_lock
, flags
);
3683 while (!list_empty(&ei
->i_completed_io_list
)){
3684 io
= list_entry(ei
->i_completed_io_list
.next
,
3685 ext4_io_end_t
, list
);
3687 * Calling ext4_end_io_nolock() to convert completed
3690 * When ext4_sync_file() is called, run_queue() may already
3691 * about to flush the work corresponding to this io structure.
3692 * It will be upset if it founds the io structure related
3693 * to the work-to-be schedule is freed.
3695 * Thus we need to keep the io structure still valid here after
3696 * convertion finished. The io structure has a flag to
3697 * avoid double converting from both fsync and background work
3700 spin_unlock_irqrestore(&ei
->i_completed_io_lock
, flags
);
3701 ret
= ext4_end_io_nolock(io
);
3702 spin_lock_irqsave(&ei
->i_completed_io_lock
, flags
);
3706 list_del_init(&io
->list
);
3708 spin_unlock_irqrestore(&ei
->i_completed_io_lock
, flags
);
3709 return (ret2
< 0) ? ret2
: 0;
3712 static void ext4_end_io_dio(struct kiocb
*iocb
, loff_t offset
,
3713 ssize_t size
, void *private, int ret
,
3716 ext4_io_end_t
*io_end
= iocb
->private;
3717 struct workqueue_struct
*wq
;
3718 unsigned long flags
;
3719 struct ext4_inode_info
*ei
;
3721 /* if not async direct IO or dio with 0 bytes write, just return */
3722 if (!io_end
|| !size
)
3725 ext_debug("ext4_end_io_dio(): io_end 0x%p"
3726 "for inode %lu, iocb 0x%p, offset %llu, size %llu\n",
3727 iocb
->private, io_end
->inode
->i_ino
, iocb
, offset
,
3730 /* if not aio dio with unwritten extents, just free io and return */
3731 if (!(io_end
->flag
& EXT4_IO_END_UNWRITTEN
)) {
3732 ext4_free_io_end(io_end
);
3733 iocb
->private = NULL
;
3736 aio_complete(iocb
, ret
, 0);
3740 io_end
->offset
= offset
;
3741 io_end
->size
= size
;
3743 io_end
->iocb
= iocb
;
3744 io_end
->result
= ret
;
3746 wq
= EXT4_SB(io_end
->inode
->i_sb
)->dio_unwritten_wq
;
3748 /* Add the io_end to per-inode completed aio dio list*/
3749 ei
= EXT4_I(io_end
->inode
);
3750 spin_lock_irqsave(&ei
->i_completed_io_lock
, flags
);
3751 list_add_tail(&io_end
->list
, &ei
->i_completed_io_list
);
3752 spin_unlock_irqrestore(&ei
->i_completed_io_lock
, flags
);
3754 /* queue the work to convert unwritten extents to written */
3755 queue_work(wq
, &io_end
->work
);
3756 iocb
->private = NULL
;
3759 static void ext4_end_io_buffer_write(struct buffer_head
*bh
, int uptodate
)
3761 ext4_io_end_t
*io_end
= bh
->b_private
;
3762 struct workqueue_struct
*wq
;
3763 struct inode
*inode
;
3764 unsigned long flags
;
3766 if (!test_clear_buffer_uninit(bh
) || !io_end
)
3769 if (!(io_end
->inode
->i_sb
->s_flags
& MS_ACTIVE
)) {
3770 printk("sb umounted, discard end_io request for inode %lu\n",
3771 io_end
->inode
->i_ino
);
3772 ext4_free_io_end(io_end
);
3776 io_end
->flag
= EXT4_IO_END_UNWRITTEN
;
3777 inode
= io_end
->inode
;
3779 /* Add the io_end to per-inode completed io list*/
3780 spin_lock_irqsave(&EXT4_I(inode
)->i_completed_io_lock
, flags
);
3781 list_add_tail(&io_end
->list
, &EXT4_I(inode
)->i_completed_io_list
);
3782 spin_unlock_irqrestore(&EXT4_I(inode
)->i_completed_io_lock
, flags
);
3784 wq
= EXT4_SB(inode
->i_sb
)->dio_unwritten_wq
;
3785 /* queue the work to convert unwritten extents to written */
3786 queue_work(wq
, &io_end
->work
);
3788 bh
->b_private
= NULL
;
3789 bh
->b_end_io
= NULL
;
3790 clear_buffer_uninit(bh
);
3791 end_buffer_async_write(bh
, uptodate
);
3794 static int ext4_set_bh_endio(struct buffer_head
*bh
, struct inode
*inode
)
3796 ext4_io_end_t
*io_end
;
3797 struct page
*page
= bh
->b_page
;
3798 loff_t offset
= (sector_t
)page
->index
<< PAGE_CACHE_SHIFT
;
3799 size_t size
= bh
->b_size
;
3802 io_end
= ext4_init_io_end(inode
, GFP_ATOMIC
);
3804 if (printk_ratelimit())
3805 printk(KERN_WARNING
"%s: allocation fail\n", __func__
);
3809 io_end
->offset
= offset
;
3810 io_end
->size
= size
;
3812 * We need to hold a reference to the page to make sure it
3813 * doesn't get evicted before ext4_end_io_work() has a chance
3814 * to convert the extent from written to unwritten.
3816 io_end
->page
= page
;
3817 get_page(io_end
->page
);
3819 bh
->b_private
= io_end
;
3820 bh
->b_end_io
= ext4_end_io_buffer_write
;
3825 * For ext4 extent files, ext4 will do direct-io write to holes,
3826 * preallocated extents, and those write extend the file, no need to
3827 * fall back to buffered IO.
3829 * For holes, we fallocate those blocks, mark them as unintialized
3830 * If those blocks were preallocated, we mark sure they are splited, but
3831 * still keep the range to write as unintialized.
3833 * The unwrritten extents will be converted to written when DIO is completed.
3834 * For async direct IO, since the IO may still pending when return, we
3835 * set up an end_io call back function, which will do the convertion
3836 * when async direct IO completed.
3838 * If the O_DIRECT write will extend the file then add this inode to the
3839 * orphan list. So recovery will truncate it back to the original size
3840 * if the machine crashes during the write.
3843 static ssize_t
ext4_ext_direct_IO(int rw
, struct kiocb
*iocb
,
3844 const struct iovec
*iov
, loff_t offset
,
3845 unsigned long nr_segs
)
3847 struct file
*file
= iocb
->ki_filp
;
3848 struct inode
*inode
= file
->f_mapping
->host
;
3850 size_t count
= iov_length(iov
, nr_segs
);
3852 loff_t final_size
= offset
+ count
;
3853 if (rw
== WRITE
&& final_size
<= inode
->i_size
) {
3855 * We could direct write to holes and fallocate.
3857 * Allocated blocks to fill the hole are marked as uninitialized
3858 * to prevent paralel buffered read to expose the stale data
3859 * before DIO complete the data IO.
3861 * As to previously fallocated extents, ext4 get_block
3862 * will just simply mark the buffer mapped but still
3863 * keep the extents uninitialized.
3865 * for non AIO case, we will convert those unwritten extents
3866 * to written after return back from blockdev_direct_IO.
3868 * for async DIO, the conversion needs to be defered when
3869 * the IO is completed. The ext4 end_io callback function
3870 * will be called to take care of the conversion work.
3871 * Here for async case, we allocate an io_end structure to
3874 iocb
->private = NULL
;
3875 EXT4_I(inode
)->cur_aio_dio
= NULL
;
3876 if (!is_sync_kiocb(iocb
)) {
3877 iocb
->private = ext4_init_io_end(inode
, GFP_NOFS
);
3881 * we save the io structure for current async
3882 * direct IO, so that later ext4_map_blocks()
3883 * could flag the io structure whether there
3884 * is a unwritten extents needs to be converted
3885 * when IO is completed.
3887 EXT4_I(inode
)->cur_aio_dio
= iocb
->private;
3890 ret
= blockdev_direct_IO(rw
, iocb
, inode
,
3891 inode
->i_sb
->s_bdev
, iov
,
3893 ext4_get_block_write
,
3896 EXT4_I(inode
)->cur_aio_dio
= NULL
;
3898 * The io_end structure takes a reference to the inode,
3899 * that structure needs to be destroyed and the
3900 * reference to the inode need to be dropped, when IO is
3901 * complete, even with 0 byte write, or failed.
3903 * In the successful AIO DIO case, the io_end structure will be
3904 * desctroyed and the reference to the inode will be dropped
3905 * after the end_io call back function is called.
3907 * In the case there is 0 byte write, or error case, since
3908 * VFS direct IO won't invoke the end_io call back function,
3909 * we need to free the end_io structure here.
3911 if (ret
!= -EIOCBQUEUED
&& ret
<= 0 && iocb
->private) {
3912 ext4_free_io_end(iocb
->private);
3913 iocb
->private = NULL
;
3914 } else if (ret
> 0 && ext4_test_inode_state(inode
,
3915 EXT4_STATE_DIO_UNWRITTEN
)) {
3918 * for non AIO case, since the IO is already
3919 * completed, we could do the convertion right here
3921 err
= ext4_convert_unwritten_extents(inode
,
3925 ext4_clear_inode_state(inode
, EXT4_STATE_DIO_UNWRITTEN
);
3930 /* for write the the end of file case, we fall back to old way */
3931 return ext4_ind_direct_IO(rw
, iocb
, iov
, offset
, nr_segs
);
3934 static ssize_t
ext4_direct_IO(int rw
, struct kiocb
*iocb
,
3935 const struct iovec
*iov
, loff_t offset
,
3936 unsigned long nr_segs
)
3938 struct file
*file
= iocb
->ki_filp
;
3939 struct inode
*inode
= file
->f_mapping
->host
;
3941 if (ext4_test_inode_flag(inode
, EXT4_INODE_EXTENTS
))
3942 return ext4_ext_direct_IO(rw
, iocb
, iov
, offset
, nr_segs
);
3944 return ext4_ind_direct_IO(rw
, iocb
, iov
, offset
, nr_segs
);
3948 * Pages can be marked dirty completely asynchronously from ext4's journalling
3949 * activity. By filemap_sync_pte(), try_to_unmap_one(), etc. We cannot do
3950 * much here because ->set_page_dirty is called under VFS locks. The page is
3951 * not necessarily locked.
3953 * We cannot just dirty the page and leave attached buffers clean, because the
3954 * buffers' dirty state is "definitive". We cannot just set the buffers dirty
3955 * or jbddirty because all the journalling code will explode.
3957 * So what we do is to mark the page "pending dirty" and next time writepage
3958 * is called, propagate that into the buffers appropriately.
3960 static int ext4_journalled_set_page_dirty(struct page
*page
)
3962 SetPageChecked(page
);
3963 return __set_page_dirty_nobuffers(page
);
3966 static const struct address_space_operations ext4_ordered_aops
= {
3967 .readpage
= ext4_readpage
,
3968 .readpages
= ext4_readpages
,
3969 .writepage
= ext4_writepage
,
3970 .sync_page
= block_sync_page
,
3971 .write_begin
= ext4_write_begin
,
3972 .write_end
= ext4_ordered_write_end
,
3974 .invalidatepage
= ext4_invalidatepage
,
3975 .releasepage
= ext4_releasepage
,
3976 .direct_IO
= ext4_direct_IO
,
3977 .migratepage
= buffer_migrate_page
,
3978 .is_partially_uptodate
= block_is_partially_uptodate
,
3979 .error_remove_page
= generic_error_remove_page
,
3982 static const struct address_space_operations ext4_writeback_aops
= {
3983 .readpage
= ext4_readpage
,
3984 .readpages
= ext4_readpages
,
3985 .writepage
= ext4_writepage
,
3986 .sync_page
= block_sync_page
,
3987 .write_begin
= ext4_write_begin
,
3988 .write_end
= ext4_writeback_write_end
,
3990 .invalidatepage
= ext4_invalidatepage
,
3991 .releasepage
= ext4_releasepage
,
3992 .direct_IO
= ext4_direct_IO
,
3993 .migratepage
= buffer_migrate_page
,
3994 .is_partially_uptodate
= block_is_partially_uptodate
,
3995 .error_remove_page
= generic_error_remove_page
,
3998 static const struct address_space_operations ext4_journalled_aops
= {
3999 .readpage
= ext4_readpage
,
4000 .readpages
= ext4_readpages
,
4001 .writepage
= ext4_writepage
,
4002 .sync_page
= block_sync_page
,
4003 .write_begin
= ext4_write_begin
,
4004 .write_end
= ext4_journalled_write_end
,
4005 .set_page_dirty
= ext4_journalled_set_page_dirty
,
4007 .invalidatepage
= ext4_invalidatepage
,
4008 .releasepage
= ext4_releasepage
,
4009 .is_partially_uptodate
= block_is_partially_uptodate
,
4010 .error_remove_page
= generic_error_remove_page
,
4013 static const struct address_space_operations ext4_da_aops
= {
4014 .readpage
= ext4_readpage
,
4015 .readpages
= ext4_readpages
,
4016 .writepage
= ext4_writepage
,
4017 .writepages
= ext4_da_writepages
,
4018 .sync_page
= block_sync_page
,
4019 .write_begin
= ext4_da_write_begin
,
4020 .write_end
= ext4_da_write_end
,
4022 .invalidatepage
= ext4_da_invalidatepage
,
4023 .releasepage
= ext4_releasepage
,
4024 .direct_IO
= ext4_direct_IO
,
4025 .migratepage
= buffer_migrate_page
,
4026 .is_partially_uptodate
= block_is_partially_uptodate
,
4027 .error_remove_page
= generic_error_remove_page
,
4030 void ext4_set_aops(struct inode
*inode
)
4032 if (ext4_should_order_data(inode
) &&
4033 test_opt(inode
->i_sb
, DELALLOC
))
4034 inode
->i_mapping
->a_ops
= &ext4_da_aops
;
4035 else if (ext4_should_order_data(inode
))
4036 inode
->i_mapping
->a_ops
= &ext4_ordered_aops
;
4037 else if (ext4_should_writeback_data(inode
) &&
4038 test_opt(inode
->i_sb
, DELALLOC
))
4039 inode
->i_mapping
->a_ops
= &ext4_da_aops
;
4040 else if (ext4_should_writeback_data(inode
))
4041 inode
->i_mapping
->a_ops
= &ext4_writeback_aops
;
4043 inode
->i_mapping
->a_ops
= &ext4_journalled_aops
;
4047 * ext4_block_truncate_page() zeroes out a mapping from file offset `from'
4048 * up to the end of the block which corresponds to `from'.
4049 * This required during truncate. We need to physically zero the tail end
4050 * of that block so it doesn't yield old data if the file is later grown.
4052 int ext4_block_truncate_page(handle_t
*handle
,
4053 struct address_space
*mapping
, loff_t from
)
4055 ext4_fsblk_t index
= from
>> PAGE_CACHE_SHIFT
;
4056 unsigned offset
= from
& (PAGE_CACHE_SIZE
-1);
4057 unsigned blocksize
, length
, pos
;
4059 struct inode
*inode
= mapping
->host
;
4060 struct buffer_head
*bh
;
4064 page
= find_or_create_page(mapping
, from
>> PAGE_CACHE_SHIFT
,
4065 mapping_gfp_mask(mapping
) & ~__GFP_FS
);
4069 blocksize
= inode
->i_sb
->s_blocksize
;
4070 length
= blocksize
- (offset
& (blocksize
- 1));
4071 iblock
= index
<< (PAGE_CACHE_SHIFT
- inode
->i_sb
->s_blocksize_bits
);
4073 if (!page_has_buffers(page
))
4074 create_empty_buffers(page
, blocksize
, 0);
4076 /* Find the buffer that contains "offset" */
4077 bh
= page_buffers(page
);
4079 while (offset
>= pos
) {
4080 bh
= bh
->b_this_page
;
4086 if (buffer_freed(bh
)) {
4087 BUFFER_TRACE(bh
, "freed: skip");
4091 if (!buffer_mapped(bh
)) {
4092 BUFFER_TRACE(bh
, "unmapped");
4093 ext4_get_block(inode
, iblock
, bh
, 0);
4094 /* unmapped? It's a hole - nothing to do */
4095 if (!buffer_mapped(bh
)) {
4096 BUFFER_TRACE(bh
, "still unmapped");
4101 /* Ok, it's mapped. Make sure it's up-to-date */
4102 if (PageUptodate(page
))
4103 set_buffer_uptodate(bh
);
4105 if (!buffer_uptodate(bh
)) {
4107 ll_rw_block(READ
, 1, &bh
);
4109 /* Uhhuh. Read error. Complain and punt. */
4110 if (!buffer_uptodate(bh
))
4114 if (ext4_should_journal_data(inode
)) {
4115 BUFFER_TRACE(bh
, "get write access");
4116 err
= ext4_journal_get_write_access(handle
, bh
);
4121 zero_user(page
, offset
, length
);
4123 BUFFER_TRACE(bh
, "zeroed end of block");
4126 if (ext4_should_journal_data(inode
)) {
4127 err
= ext4_handle_dirty_metadata(handle
, inode
, bh
);
4129 if (ext4_should_order_data(inode
))
4130 err
= ext4_jbd2_file_inode(handle
, inode
);
4131 mark_buffer_dirty(bh
);
4136 page_cache_release(page
);
4141 * Probably it should be a library function... search for first non-zero word
4142 * or memcmp with zero_page, whatever is better for particular architecture.
4145 static inline int all_zeroes(__le32
*p
, __le32
*q
)
4154 * ext4_find_shared - find the indirect blocks for partial truncation.
4155 * @inode: inode in question
4156 * @depth: depth of the affected branch
4157 * @offsets: offsets of pointers in that branch (see ext4_block_to_path)
4158 * @chain: place to store the pointers to partial indirect blocks
4159 * @top: place to the (detached) top of branch
4161 * This is a helper function used by ext4_truncate().
4163 * When we do truncate() we may have to clean the ends of several
4164 * indirect blocks but leave the blocks themselves alive. Block is
4165 * partially truncated if some data below the new i_size is refered
4166 * from it (and it is on the path to the first completely truncated
4167 * data block, indeed). We have to free the top of that path along
4168 * with everything to the right of the path. Since no allocation
4169 * past the truncation point is possible until ext4_truncate()
4170 * finishes, we may safely do the latter, but top of branch may
4171 * require special attention - pageout below the truncation point
4172 * might try to populate it.
4174 * We atomically detach the top of branch from the tree, store the
4175 * block number of its root in *@top, pointers to buffer_heads of
4176 * partially truncated blocks - in @chain[].bh and pointers to
4177 * their last elements that should not be removed - in
4178 * @chain[].p. Return value is the pointer to last filled element
4181 * The work left to caller to do the actual freeing of subtrees:
4182 * a) free the subtree starting from *@top
4183 * b) free the subtrees whose roots are stored in
4184 * (@chain[i].p+1 .. end of @chain[i].bh->b_data)
4185 * c) free the subtrees growing from the inode past the @chain[0].
4186 * (no partially truncated stuff there). */
4188 static Indirect
*ext4_find_shared(struct inode
*inode
, int depth
,
4189 ext4_lblk_t offsets
[4], Indirect chain
[4],
4192 Indirect
*partial
, *p
;
4196 /* Make k index the deepest non-null offset + 1 */
4197 for (k
= depth
; k
> 1 && !offsets
[k
-1]; k
--)
4199 partial
= ext4_get_branch(inode
, k
, offsets
, chain
, &err
);
4200 /* Writer: pointers */
4202 partial
= chain
+ k
-1;
4204 * If the branch acquired continuation since we've looked at it -
4205 * fine, it should all survive and (new) top doesn't belong to us.
4207 if (!partial
->key
&& *partial
->p
)
4210 for (p
= partial
; (p
> chain
) && all_zeroes((__le32
*) p
->bh
->b_data
, p
->p
); p
--)
4213 * OK, we've found the last block that must survive. The rest of our
4214 * branch should be detached before unlocking. However, if that rest
4215 * of branch is all ours and does not grow immediately from the inode
4216 * it's easier to cheat and just decrement partial->p.
4218 if (p
== chain
+ k
- 1 && p
> chain
) {
4222 /* Nope, don't do this in ext4. Must leave the tree intact */
4229 while (partial
> p
) {
4230 brelse(partial
->bh
);
4238 * Zero a number of block pointers in either an inode or an indirect block.
4239 * If we restart the transaction we must again get write access to the
4240 * indirect block for further modification.
4242 * We release `count' blocks on disk, but (last - first) may be greater
4243 * than `count' because there can be holes in there.
4245 static int ext4_clear_blocks(handle_t
*handle
, struct inode
*inode
,
4246 struct buffer_head
*bh
,
4247 ext4_fsblk_t block_to_free
,
4248 unsigned long count
, __le32
*first
,
4252 int flags
= EXT4_FREE_BLOCKS_FORGET
| EXT4_FREE_BLOCKS_VALIDATED
;
4254 if (S_ISDIR(inode
->i_mode
) || S_ISLNK(inode
->i_mode
))
4255 flags
|= EXT4_FREE_BLOCKS_METADATA
;
4257 if (!ext4_data_block_valid(EXT4_SB(inode
->i_sb
), block_to_free
,
4259 EXT4_ERROR_INODE(inode
, "attempt to clear invalid "
4260 "blocks %llu len %lu",
4261 (unsigned long long) block_to_free
, count
);
4265 if (try_to_extend_transaction(handle
, inode
)) {
4267 BUFFER_TRACE(bh
, "call ext4_handle_dirty_metadata");
4268 ext4_handle_dirty_metadata(handle
, inode
, bh
);
4270 ext4_mark_inode_dirty(handle
, inode
);
4271 ext4_truncate_restart_trans(handle
, inode
,
4272 blocks_for_truncate(inode
));
4274 BUFFER_TRACE(bh
, "retaking write access");
4275 ext4_journal_get_write_access(handle
, bh
);
4279 for (p
= first
; p
< last
; p
++)
4282 ext4_free_blocks(handle
, inode
, 0, block_to_free
, count
, flags
);
4287 * ext4_free_data - free a list of data blocks
4288 * @handle: handle for this transaction
4289 * @inode: inode we are dealing with
4290 * @this_bh: indirect buffer_head which contains *@first and *@last
4291 * @first: array of block numbers
4292 * @last: points immediately past the end of array
4294 * We are freeing all blocks refered from that array (numbers are stored as
4295 * little-endian 32-bit) and updating @inode->i_blocks appropriately.
4297 * We accumulate contiguous runs of blocks to free. Conveniently, if these
4298 * blocks are contiguous then releasing them at one time will only affect one
4299 * or two bitmap blocks (+ group descriptor(s) and superblock) and we won't
4300 * actually use a lot of journal space.
4302 * @this_bh will be %NULL if @first and @last point into the inode's direct
4305 static void ext4_free_data(handle_t
*handle
, struct inode
*inode
,
4306 struct buffer_head
*this_bh
,
4307 __le32
*first
, __le32
*last
)
4309 ext4_fsblk_t block_to_free
= 0; /* Starting block # of a run */
4310 unsigned long count
= 0; /* Number of blocks in the run */
4311 __le32
*block_to_free_p
= NULL
; /* Pointer into inode/ind
4314 ext4_fsblk_t nr
; /* Current block # */
4315 __le32
*p
; /* Pointer into inode/ind
4316 for current block */
4319 if (this_bh
) { /* For indirect block */
4320 BUFFER_TRACE(this_bh
, "get_write_access");
4321 err
= ext4_journal_get_write_access(handle
, this_bh
);
4322 /* Important: if we can't update the indirect pointers
4323 * to the blocks, we can't free them. */
4328 for (p
= first
; p
< last
; p
++) {
4329 nr
= le32_to_cpu(*p
);
4331 /* accumulate blocks to free if they're contiguous */
4334 block_to_free_p
= p
;
4336 } else if (nr
== block_to_free
+ count
) {
4339 if (ext4_clear_blocks(handle
, inode
, this_bh
,
4340 block_to_free
, count
,
4341 block_to_free_p
, p
))
4344 block_to_free_p
= p
;
4351 ext4_clear_blocks(handle
, inode
, this_bh
, block_to_free
,
4352 count
, block_to_free_p
, p
);
4355 BUFFER_TRACE(this_bh
, "call ext4_handle_dirty_metadata");
4358 * The buffer head should have an attached journal head at this
4359 * point. However, if the data is corrupted and an indirect
4360 * block pointed to itself, it would have been detached when
4361 * the block was cleared. Check for this instead of OOPSing.
4363 if ((EXT4_JOURNAL(inode
) == NULL
) || bh2jh(this_bh
))
4364 ext4_handle_dirty_metadata(handle
, inode
, this_bh
);
4366 EXT4_ERROR_INODE(inode
,
4367 "circular indirect block detected at "
4369 (unsigned long long) this_bh
->b_blocknr
);
4374 * ext4_free_branches - free an array of branches
4375 * @handle: JBD handle for this transaction
4376 * @inode: inode we are dealing with
4377 * @parent_bh: the buffer_head which contains *@first and *@last
4378 * @first: array of block numbers
4379 * @last: pointer immediately past the end of array
4380 * @depth: depth of the branches to free
4382 * We are freeing all blocks refered from these branches (numbers are
4383 * stored as little-endian 32-bit) and updating @inode->i_blocks
4386 static void ext4_free_branches(handle_t
*handle
, struct inode
*inode
,
4387 struct buffer_head
*parent_bh
,
4388 __le32
*first
, __le32
*last
, int depth
)
4393 if (ext4_handle_is_aborted(handle
))
4397 struct buffer_head
*bh
;
4398 int addr_per_block
= EXT4_ADDR_PER_BLOCK(inode
->i_sb
);
4400 while (--p
>= first
) {
4401 nr
= le32_to_cpu(*p
);
4403 continue; /* A hole */
4405 if (!ext4_data_block_valid(EXT4_SB(inode
->i_sb
),
4407 EXT4_ERROR_INODE(inode
,
4408 "invalid indirect mapped "
4409 "block %lu (level %d)",
4410 (unsigned long) nr
, depth
);
4414 /* Go read the buffer for the next level down */
4415 bh
= sb_bread(inode
->i_sb
, nr
);
4418 * A read failure? Report error and clear slot
4422 EXT4_ERROR_INODE_BLOCK(inode
, nr
,
4427 /* This zaps the entire block. Bottom up. */
4428 BUFFER_TRACE(bh
, "free child branches");
4429 ext4_free_branches(handle
, inode
, bh
,
4430 (__le32
*) bh
->b_data
,
4431 (__le32
*) bh
->b_data
+ addr_per_block
,
4435 * Everything below this this pointer has been
4436 * released. Now let this top-of-subtree go.
4438 * We want the freeing of this indirect block to be
4439 * atomic in the journal with the updating of the
4440 * bitmap block which owns it. So make some room in
4443 * We zero the parent pointer *after* freeing its
4444 * pointee in the bitmaps, so if extend_transaction()
4445 * for some reason fails to put the bitmap changes and
4446 * the release into the same transaction, recovery
4447 * will merely complain about releasing a free block,
4448 * rather than leaking blocks.
4450 if (ext4_handle_is_aborted(handle
))
4452 if (try_to_extend_transaction(handle
, inode
)) {
4453 ext4_mark_inode_dirty(handle
, inode
);
4454 ext4_truncate_restart_trans(handle
, inode
,
4455 blocks_for_truncate(inode
));
4459 * The forget flag here is critical because if
4460 * we are journaling (and not doing data
4461 * journaling), we have to make sure a revoke
4462 * record is written to prevent the journal
4463 * replay from overwriting the (former)
4464 * indirect block if it gets reallocated as a
4465 * data block. This must happen in the same
4466 * transaction where the data blocks are
4469 ext4_free_blocks(handle
, inode
, 0, nr
, 1,
4470 EXT4_FREE_BLOCKS_METADATA
|
4471 EXT4_FREE_BLOCKS_FORGET
);
4475 * The block which we have just freed is
4476 * pointed to by an indirect block: journal it
4478 BUFFER_TRACE(parent_bh
, "get_write_access");
4479 if (!ext4_journal_get_write_access(handle
,
4482 BUFFER_TRACE(parent_bh
,
4483 "call ext4_handle_dirty_metadata");
4484 ext4_handle_dirty_metadata(handle
,
4491 /* We have reached the bottom of the tree. */
4492 BUFFER_TRACE(parent_bh
, "free data blocks");
4493 ext4_free_data(handle
, inode
, parent_bh
, first
, last
);
4497 int ext4_can_truncate(struct inode
*inode
)
4499 if (IS_APPEND(inode
) || IS_IMMUTABLE(inode
))
4501 if (S_ISREG(inode
->i_mode
))
4503 if (S_ISDIR(inode
->i_mode
))
4505 if (S_ISLNK(inode
->i_mode
))
4506 return !ext4_inode_is_fast_symlink(inode
);
4513 * We block out ext4_get_block() block instantiations across the entire
4514 * transaction, and VFS/VM ensures that ext4_truncate() cannot run
4515 * simultaneously on behalf of the same inode.
4517 * As we work through the truncate and commmit bits of it to the journal there
4518 * is one core, guiding principle: the file's tree must always be consistent on
4519 * disk. We must be able to restart the truncate after a crash.
4521 * The file's tree may be transiently inconsistent in memory (although it
4522 * probably isn't), but whenever we close off and commit a journal transaction,
4523 * the contents of (the filesystem + the journal) must be consistent and
4524 * restartable. It's pretty simple, really: bottom up, right to left (although
4525 * left-to-right works OK too).
4527 * Note that at recovery time, journal replay occurs *before* the restart of
4528 * truncate against the orphan inode list.
4530 * The committed inode has the new, desired i_size (which is the same as
4531 * i_disksize in this case). After a crash, ext4_orphan_cleanup() will see
4532 * that this inode's truncate did not complete and it will again call
4533 * ext4_truncate() to have another go. So there will be instantiated blocks
4534 * to the right of the truncation point in a crashed ext4 filesystem. But
4535 * that's fine - as long as they are linked from the inode, the post-crash
4536 * ext4_truncate() run will find them and release them.
4538 void ext4_truncate(struct inode
*inode
)
4541 struct ext4_inode_info
*ei
= EXT4_I(inode
);
4542 __le32
*i_data
= ei
->i_data
;
4543 int addr_per_block
= EXT4_ADDR_PER_BLOCK(inode
->i_sb
);
4544 struct address_space
*mapping
= inode
->i_mapping
;
4545 ext4_lblk_t offsets
[4];
4550 ext4_lblk_t last_block
;
4551 unsigned blocksize
= inode
->i_sb
->s_blocksize
;
4553 if (!ext4_can_truncate(inode
))
4556 ext4_clear_inode_flag(inode
, EXT4_INODE_EOFBLOCKS
);
4558 if (inode
->i_size
== 0 && !test_opt(inode
->i_sb
, NO_AUTO_DA_ALLOC
))
4559 ext4_set_inode_state(inode
, EXT4_STATE_DA_ALLOC_CLOSE
);
4561 if (ext4_test_inode_flag(inode
, EXT4_INODE_EXTENTS
)) {
4562 ext4_ext_truncate(inode
);
4566 handle
= start_transaction(inode
);
4568 return; /* AKPM: return what? */
4570 last_block
= (inode
->i_size
+ blocksize
-1)
4571 >> EXT4_BLOCK_SIZE_BITS(inode
->i_sb
);
4573 if (inode
->i_size
& (blocksize
- 1))
4574 if (ext4_block_truncate_page(handle
, mapping
, inode
->i_size
))
4577 n
= ext4_block_to_path(inode
, last_block
, offsets
, NULL
);
4579 goto out_stop
; /* error */
4582 * OK. This truncate is going to happen. We add the inode to the
4583 * orphan list, so that if this truncate spans multiple transactions,
4584 * and we crash, we will resume the truncate when the filesystem
4585 * recovers. It also marks the inode dirty, to catch the new size.
4587 * Implication: the file must always be in a sane, consistent
4588 * truncatable state while each transaction commits.
4590 if (ext4_orphan_add(handle
, inode
))
4594 * From here we block out all ext4_get_block() callers who want to
4595 * modify the block allocation tree.
4597 down_write(&ei
->i_data_sem
);
4599 ext4_discard_preallocations(inode
);
4602 * The orphan list entry will now protect us from any crash which
4603 * occurs before the truncate completes, so it is now safe to propagate
4604 * the new, shorter inode size (held for now in i_size) into the
4605 * on-disk inode. We do this via i_disksize, which is the value which
4606 * ext4 *really* writes onto the disk inode.
4608 ei
->i_disksize
= inode
->i_size
;
4610 if (n
== 1) { /* direct blocks */
4611 ext4_free_data(handle
, inode
, NULL
, i_data
+offsets
[0],
4612 i_data
+ EXT4_NDIR_BLOCKS
);
4616 partial
= ext4_find_shared(inode
, n
, offsets
, chain
, &nr
);
4617 /* Kill the top of shared branch (not detached) */
4619 if (partial
== chain
) {
4620 /* Shared branch grows from the inode */
4621 ext4_free_branches(handle
, inode
, NULL
,
4622 &nr
, &nr
+1, (chain
+n
-1) - partial
);
4625 * We mark the inode dirty prior to restart,
4626 * and prior to stop. No need for it here.
4629 /* Shared branch grows from an indirect block */
4630 BUFFER_TRACE(partial
->bh
, "get_write_access");
4631 ext4_free_branches(handle
, inode
, partial
->bh
,
4633 partial
->p
+1, (chain
+n
-1) - partial
);
4636 /* Clear the ends of indirect blocks on the shared branch */
4637 while (partial
> chain
) {
4638 ext4_free_branches(handle
, inode
, partial
->bh
, partial
->p
+ 1,
4639 (__le32
*)partial
->bh
->b_data
+addr_per_block
,
4640 (chain
+n
-1) - partial
);
4641 BUFFER_TRACE(partial
->bh
, "call brelse");
4642 brelse(partial
->bh
);
4646 /* Kill the remaining (whole) subtrees */
4647 switch (offsets
[0]) {
4649 nr
= i_data
[EXT4_IND_BLOCK
];
4651 ext4_free_branches(handle
, inode
, NULL
, &nr
, &nr
+1, 1);
4652 i_data
[EXT4_IND_BLOCK
] = 0;
4654 case EXT4_IND_BLOCK
:
4655 nr
= i_data
[EXT4_DIND_BLOCK
];
4657 ext4_free_branches(handle
, inode
, NULL
, &nr
, &nr
+1, 2);
4658 i_data
[EXT4_DIND_BLOCK
] = 0;
4660 case EXT4_DIND_BLOCK
:
4661 nr
= i_data
[EXT4_TIND_BLOCK
];
4663 ext4_free_branches(handle
, inode
, NULL
, &nr
, &nr
+1, 3);
4664 i_data
[EXT4_TIND_BLOCK
] = 0;
4666 case EXT4_TIND_BLOCK
:
4670 up_write(&ei
->i_data_sem
);
4671 inode
->i_mtime
= inode
->i_ctime
= ext4_current_time(inode
);
4672 ext4_mark_inode_dirty(handle
, inode
);
4675 * In a multi-transaction truncate, we only make the final transaction
4679 ext4_handle_sync(handle
);
4682 * If this was a simple ftruncate(), and the file will remain alive
4683 * then we need to clear up the orphan record which we created above.
4684 * However, if this was a real unlink then we were called by
4685 * ext4_delete_inode(), and we allow that function to clean up the
4686 * orphan info for us.
4689 ext4_orphan_del(handle
, inode
);
4691 ext4_journal_stop(handle
);
4695 * ext4_get_inode_loc returns with an extra refcount against the inode's
4696 * underlying buffer_head on success. If 'in_mem' is true, we have all
4697 * data in memory that is needed to recreate the on-disk version of this
4700 static int __ext4_get_inode_loc(struct inode
*inode
,
4701 struct ext4_iloc
*iloc
, int in_mem
)
4703 struct ext4_group_desc
*gdp
;
4704 struct buffer_head
*bh
;
4705 struct super_block
*sb
= inode
->i_sb
;
4707 int inodes_per_block
, inode_offset
;
4710 if (!ext4_valid_inum(sb
, inode
->i_ino
))
4713 iloc
->block_group
= (inode
->i_ino
- 1) / EXT4_INODES_PER_GROUP(sb
);
4714 gdp
= ext4_get_group_desc(sb
, iloc
->block_group
, NULL
);
4719 * Figure out the offset within the block group inode table
4721 inodes_per_block
= (EXT4_BLOCK_SIZE(sb
) / EXT4_INODE_SIZE(sb
));
4722 inode_offset
= ((inode
->i_ino
- 1) %
4723 EXT4_INODES_PER_GROUP(sb
));
4724 block
= ext4_inode_table(sb
, gdp
) + (inode_offset
/ inodes_per_block
);
4725 iloc
->offset
= (inode_offset
% inodes_per_block
) * EXT4_INODE_SIZE(sb
);
4727 bh
= sb_getblk(sb
, block
);
4729 EXT4_ERROR_INODE_BLOCK(inode
, block
,
4730 "unable to read itable block");
4733 if (!buffer_uptodate(bh
)) {
4737 * If the buffer has the write error flag, we have failed
4738 * to write out another inode in the same block. In this
4739 * case, we don't have to read the block because we may
4740 * read the old inode data successfully.
4742 if (buffer_write_io_error(bh
) && !buffer_uptodate(bh
))
4743 set_buffer_uptodate(bh
);
4745 if (buffer_uptodate(bh
)) {
4746 /* someone brought it uptodate while we waited */
4752 * If we have all information of the inode in memory and this
4753 * is the only valid inode in the block, we need not read the
4757 struct buffer_head
*bitmap_bh
;
4760 start
= inode_offset
& ~(inodes_per_block
- 1);
4762 /* Is the inode bitmap in cache? */
4763 bitmap_bh
= sb_getblk(sb
, ext4_inode_bitmap(sb
, gdp
));
4768 * If the inode bitmap isn't in cache then the
4769 * optimisation may end up performing two reads instead
4770 * of one, so skip it.
4772 if (!buffer_uptodate(bitmap_bh
)) {
4776 for (i
= start
; i
< start
+ inodes_per_block
; i
++) {
4777 if (i
== inode_offset
)
4779 if (ext4_test_bit(i
, bitmap_bh
->b_data
))
4783 if (i
== start
+ inodes_per_block
) {
4784 /* all other inodes are free, so skip I/O */
4785 memset(bh
->b_data
, 0, bh
->b_size
);
4786 set_buffer_uptodate(bh
);
4794 * If we need to do any I/O, try to pre-readahead extra
4795 * blocks from the inode table.
4797 if (EXT4_SB(sb
)->s_inode_readahead_blks
) {
4798 ext4_fsblk_t b
, end
, table
;
4801 table
= ext4_inode_table(sb
, gdp
);
4802 /* s_inode_readahead_blks is always a power of 2 */
4803 b
= block
& ~(EXT4_SB(sb
)->s_inode_readahead_blks
-1);
4806 end
= b
+ EXT4_SB(sb
)->s_inode_readahead_blks
;
4807 num
= EXT4_INODES_PER_GROUP(sb
);
4808 if (EXT4_HAS_RO_COMPAT_FEATURE(sb
,
4809 EXT4_FEATURE_RO_COMPAT_GDT_CSUM
))
4810 num
-= ext4_itable_unused_count(sb
, gdp
);
4811 table
+= num
/ inodes_per_block
;
4815 sb_breadahead(sb
, b
++);
4819 * There are other valid inodes in the buffer, this inode
4820 * has in-inode xattrs, or we don't have this inode in memory.
4821 * Read the block from disk.
4824 bh
->b_end_io
= end_buffer_read_sync
;
4825 submit_bh(READ_META
, bh
);
4827 if (!buffer_uptodate(bh
)) {
4828 EXT4_ERROR_INODE_BLOCK(inode
, block
,
4829 "unable to read itable block");
4839 int ext4_get_inode_loc(struct inode
*inode
, struct ext4_iloc
*iloc
)
4841 /* We have all inode data except xattrs in memory here. */
4842 return __ext4_get_inode_loc(inode
, iloc
,
4843 !ext4_test_inode_state(inode
, EXT4_STATE_XATTR
));
4846 void ext4_set_inode_flags(struct inode
*inode
)
4848 unsigned int flags
= EXT4_I(inode
)->i_flags
;
4850 inode
->i_flags
&= ~(S_SYNC
|S_APPEND
|S_IMMUTABLE
|S_NOATIME
|S_DIRSYNC
);
4851 if (flags
& EXT4_SYNC_FL
)
4852 inode
->i_flags
|= S_SYNC
;
4853 if (flags
& EXT4_APPEND_FL
)
4854 inode
->i_flags
|= S_APPEND
;
4855 if (flags
& EXT4_IMMUTABLE_FL
)
4856 inode
->i_flags
|= S_IMMUTABLE
;
4857 if (flags
& EXT4_NOATIME_FL
)
4858 inode
->i_flags
|= S_NOATIME
;
4859 if (flags
& EXT4_DIRSYNC_FL
)
4860 inode
->i_flags
|= S_DIRSYNC
;
4863 /* Propagate flags from i_flags to EXT4_I(inode)->i_flags */
4864 void ext4_get_inode_flags(struct ext4_inode_info
*ei
)
4866 unsigned int vfs_fl
;
4867 unsigned long old_fl
, new_fl
;
4870 vfs_fl
= ei
->vfs_inode
.i_flags
;
4871 old_fl
= ei
->i_flags
;
4872 new_fl
= old_fl
& ~(EXT4_SYNC_FL
|EXT4_APPEND_FL
|
4873 EXT4_IMMUTABLE_FL
|EXT4_NOATIME_FL
|
4875 if (vfs_fl
& S_SYNC
)
4876 new_fl
|= EXT4_SYNC_FL
;
4877 if (vfs_fl
& S_APPEND
)
4878 new_fl
|= EXT4_APPEND_FL
;
4879 if (vfs_fl
& S_IMMUTABLE
)
4880 new_fl
|= EXT4_IMMUTABLE_FL
;
4881 if (vfs_fl
& S_NOATIME
)
4882 new_fl
|= EXT4_NOATIME_FL
;
4883 if (vfs_fl
& S_DIRSYNC
)
4884 new_fl
|= EXT4_DIRSYNC_FL
;
4885 } while (cmpxchg(&ei
->i_flags
, old_fl
, new_fl
) != old_fl
);
4888 static blkcnt_t
ext4_inode_blocks(struct ext4_inode
*raw_inode
,
4889 struct ext4_inode_info
*ei
)
4892 struct inode
*inode
= &(ei
->vfs_inode
);
4893 struct super_block
*sb
= inode
->i_sb
;
4895 if (EXT4_HAS_RO_COMPAT_FEATURE(sb
,
4896 EXT4_FEATURE_RO_COMPAT_HUGE_FILE
)) {
4897 /* we are using combined 48 bit field */
4898 i_blocks
= ((u64
)le16_to_cpu(raw_inode
->i_blocks_high
)) << 32 |
4899 le32_to_cpu(raw_inode
->i_blocks_lo
);
4900 if (ext4_test_inode_flag(inode
, EXT4_INODE_HUGE_FILE
)) {
4901 /* i_blocks represent file system block size */
4902 return i_blocks
<< (inode
->i_blkbits
- 9);
4907 return le32_to_cpu(raw_inode
->i_blocks_lo
);
4911 struct inode
*ext4_iget(struct super_block
*sb
, unsigned long ino
)
4913 struct ext4_iloc iloc
;
4914 struct ext4_inode
*raw_inode
;
4915 struct ext4_inode_info
*ei
;
4916 struct inode
*inode
;
4917 journal_t
*journal
= EXT4_SB(sb
)->s_journal
;
4921 inode
= iget_locked(sb
, ino
);
4923 return ERR_PTR(-ENOMEM
);
4924 if (!(inode
->i_state
& I_NEW
))
4930 ret
= __ext4_get_inode_loc(inode
, &iloc
, 0);
4933 raw_inode
= ext4_raw_inode(&iloc
);
4934 inode
->i_mode
= le16_to_cpu(raw_inode
->i_mode
);
4935 inode
->i_uid
= (uid_t
)le16_to_cpu(raw_inode
->i_uid_low
);
4936 inode
->i_gid
= (gid_t
)le16_to_cpu(raw_inode
->i_gid_low
);
4937 if (!(test_opt(inode
->i_sb
, NO_UID32
))) {
4938 inode
->i_uid
|= le16_to_cpu(raw_inode
->i_uid_high
) << 16;
4939 inode
->i_gid
|= le16_to_cpu(raw_inode
->i_gid_high
) << 16;
4941 inode
->i_nlink
= le16_to_cpu(raw_inode
->i_links_count
);
4943 ei
->i_state_flags
= 0;
4944 ei
->i_dir_start_lookup
= 0;
4945 ei
->i_dtime
= le32_to_cpu(raw_inode
->i_dtime
);
4946 /* We now have enough fields to check if the inode was active or not.
4947 * This is needed because nfsd might try to access dead inodes
4948 * the test is that same one that e2fsck uses
4949 * NeilBrown 1999oct15
4951 if (inode
->i_nlink
== 0) {
4952 if (inode
->i_mode
== 0 ||
4953 !(EXT4_SB(inode
->i_sb
)->s_mount_state
& EXT4_ORPHAN_FS
)) {
4954 /* this inode is deleted */
4958 /* The only unlinked inodes we let through here have
4959 * valid i_mode and are being read by the orphan
4960 * recovery code: that's fine, we're about to complete
4961 * the process of deleting those. */
4963 ei
->i_flags
= le32_to_cpu(raw_inode
->i_flags
);
4964 inode
->i_blocks
= ext4_inode_blocks(raw_inode
, ei
);
4965 ei
->i_file_acl
= le32_to_cpu(raw_inode
->i_file_acl_lo
);
4966 if (EXT4_HAS_INCOMPAT_FEATURE(sb
, EXT4_FEATURE_INCOMPAT_64BIT
))
4968 ((__u64
)le16_to_cpu(raw_inode
->i_file_acl_high
)) << 32;
4969 inode
->i_size
= ext4_isize(raw_inode
);
4970 ei
->i_disksize
= inode
->i_size
;
4972 ei
->i_reserved_quota
= 0;
4974 inode
->i_generation
= le32_to_cpu(raw_inode
->i_generation
);
4975 ei
->i_block_group
= iloc
.block_group
;
4976 ei
->i_last_alloc_group
= ~0;
4978 * NOTE! The in-memory inode i_data array is in little-endian order
4979 * even on big-endian machines: we do NOT byteswap the block numbers!
4981 for (block
= 0; block
< EXT4_N_BLOCKS
; block
++)
4982 ei
->i_data
[block
] = raw_inode
->i_block
[block
];
4983 INIT_LIST_HEAD(&ei
->i_orphan
);
4986 * Set transaction id's of transactions that have to be committed
4987 * to finish f[data]sync. We set them to currently running transaction
4988 * as we cannot be sure that the inode or some of its metadata isn't
4989 * part of the transaction - the inode could have been reclaimed and
4990 * now it is reread from disk.
4993 transaction_t
*transaction
;
4996 read_lock(&journal
->j_state_lock
);
4997 if (journal
->j_running_transaction
)
4998 transaction
= journal
->j_running_transaction
;
5000 transaction
= journal
->j_committing_transaction
;
5002 tid
= transaction
->t_tid
;
5004 tid
= journal
->j_commit_sequence
;
5005 read_unlock(&journal
->j_state_lock
);
5006 ei
->i_sync_tid
= tid
;
5007 ei
->i_datasync_tid
= tid
;
5010 if (EXT4_INODE_SIZE(inode
->i_sb
) > EXT4_GOOD_OLD_INODE_SIZE
) {
5011 ei
->i_extra_isize
= le16_to_cpu(raw_inode
->i_extra_isize
);
5012 if (EXT4_GOOD_OLD_INODE_SIZE
+ ei
->i_extra_isize
>
5013 EXT4_INODE_SIZE(inode
->i_sb
)) {
5017 if (ei
->i_extra_isize
== 0) {
5018 /* The extra space is currently unused. Use it. */
5019 ei
->i_extra_isize
= sizeof(struct ext4_inode
) -
5020 EXT4_GOOD_OLD_INODE_SIZE
;
5022 __le32
*magic
= (void *)raw_inode
+
5023 EXT4_GOOD_OLD_INODE_SIZE
+
5025 if (*magic
== cpu_to_le32(EXT4_XATTR_MAGIC
))
5026 ext4_set_inode_state(inode
, EXT4_STATE_XATTR
);
5029 ei
->i_extra_isize
= 0;
5031 EXT4_INODE_GET_XTIME(i_ctime
, inode
, raw_inode
);
5032 EXT4_INODE_GET_XTIME(i_mtime
, inode
, raw_inode
);
5033 EXT4_INODE_GET_XTIME(i_atime
, inode
, raw_inode
);
5034 EXT4_EINODE_GET_XTIME(i_crtime
, ei
, raw_inode
);
5036 inode
->i_version
= le32_to_cpu(raw_inode
->i_disk_version
);
5037 if (EXT4_INODE_SIZE(inode
->i_sb
) > EXT4_GOOD_OLD_INODE_SIZE
) {
5038 if (EXT4_FITS_IN_INODE(raw_inode
, ei
, i_version_hi
))
5040 (__u64
)(le32_to_cpu(raw_inode
->i_version_hi
)) << 32;
5044 if (ei
->i_file_acl
&&
5045 !ext4_data_block_valid(EXT4_SB(sb
), ei
->i_file_acl
, 1)) {
5046 EXT4_ERROR_INODE(inode
, "bad extended attribute block %llu",
5050 } else if (ext4_test_inode_flag(inode
, EXT4_INODE_EXTENTS
)) {
5051 if (S_ISREG(inode
->i_mode
) || S_ISDIR(inode
->i_mode
) ||
5052 (S_ISLNK(inode
->i_mode
) &&
5053 !ext4_inode_is_fast_symlink(inode
)))
5054 /* Validate extent which is part of inode */
5055 ret
= ext4_ext_check_inode(inode
);
5056 } else if (S_ISREG(inode
->i_mode
) || S_ISDIR(inode
->i_mode
) ||
5057 (S_ISLNK(inode
->i_mode
) &&
5058 !ext4_inode_is_fast_symlink(inode
))) {
5059 /* Validate block references which are part of inode */
5060 ret
= ext4_check_inode_blockref(inode
);
5065 if (S_ISREG(inode
->i_mode
)) {
5066 inode
->i_op
= &ext4_file_inode_operations
;
5067 inode
->i_fop
= &ext4_file_operations
;
5068 ext4_set_aops(inode
);
5069 } else if (S_ISDIR(inode
->i_mode
)) {
5070 inode
->i_op
= &ext4_dir_inode_operations
;
5071 inode
->i_fop
= &ext4_dir_operations
;
5072 } else if (S_ISLNK(inode
->i_mode
)) {
5073 if (ext4_inode_is_fast_symlink(inode
)) {
5074 inode
->i_op
= &ext4_fast_symlink_inode_operations
;
5075 nd_terminate_link(ei
->i_data
, inode
->i_size
,
5076 sizeof(ei
->i_data
) - 1);
5078 inode
->i_op
= &ext4_symlink_inode_operations
;
5079 ext4_set_aops(inode
);
5081 } else if (S_ISCHR(inode
->i_mode
) || S_ISBLK(inode
->i_mode
) ||
5082 S_ISFIFO(inode
->i_mode
) || S_ISSOCK(inode
->i_mode
)) {
5083 inode
->i_op
= &ext4_special_inode_operations
;
5084 if (raw_inode
->i_block
[0])
5085 init_special_inode(inode
, inode
->i_mode
,
5086 old_decode_dev(le32_to_cpu(raw_inode
->i_block
[0])));
5088 init_special_inode(inode
, inode
->i_mode
,
5089 new_decode_dev(le32_to_cpu(raw_inode
->i_block
[1])));
5092 EXT4_ERROR_INODE(inode
, "bogus i_mode (%o)", inode
->i_mode
);
5096 ext4_set_inode_flags(inode
);
5097 unlock_new_inode(inode
);
5103 return ERR_PTR(ret
);
5106 static int ext4_inode_blocks_set(handle_t
*handle
,
5107 struct ext4_inode
*raw_inode
,
5108 struct ext4_inode_info
*ei
)
5110 struct inode
*inode
= &(ei
->vfs_inode
);
5111 u64 i_blocks
= inode
->i_blocks
;
5112 struct super_block
*sb
= inode
->i_sb
;
5114 if (i_blocks
<= ~0U) {
5116 * i_blocks can be represnted in a 32 bit variable
5117 * as multiple of 512 bytes
5119 raw_inode
->i_blocks_lo
= cpu_to_le32(i_blocks
);
5120 raw_inode
->i_blocks_high
= 0;
5121 ext4_clear_inode_flag(inode
, EXT4_INODE_HUGE_FILE
);
5124 if (!EXT4_HAS_RO_COMPAT_FEATURE(sb
, EXT4_FEATURE_RO_COMPAT_HUGE_FILE
))
5127 if (i_blocks
<= 0xffffffffffffULL
) {
5129 * i_blocks can be represented in a 48 bit variable
5130 * as multiple of 512 bytes
5132 raw_inode
->i_blocks_lo
= cpu_to_le32(i_blocks
);
5133 raw_inode
->i_blocks_high
= cpu_to_le16(i_blocks
>> 32);
5134 ext4_clear_inode_flag(inode
, EXT4_INODE_HUGE_FILE
);
5136 ext4_set_inode_flag(inode
, EXT4_INODE_HUGE_FILE
);
5137 /* i_block is stored in file system block size */
5138 i_blocks
= i_blocks
>> (inode
->i_blkbits
- 9);
5139 raw_inode
->i_blocks_lo
= cpu_to_le32(i_blocks
);
5140 raw_inode
->i_blocks_high
= cpu_to_le16(i_blocks
>> 32);
5146 * Post the struct inode info into an on-disk inode location in the
5147 * buffer-cache. This gobbles the caller's reference to the
5148 * buffer_head in the inode location struct.
5150 * The caller must have write access to iloc->bh.
5152 static int ext4_do_update_inode(handle_t
*handle
,
5153 struct inode
*inode
,
5154 struct ext4_iloc
*iloc
)
5156 struct ext4_inode
*raw_inode
= ext4_raw_inode(iloc
);
5157 struct ext4_inode_info
*ei
= EXT4_I(inode
);
5158 struct buffer_head
*bh
= iloc
->bh
;
5159 int err
= 0, rc
, block
;
5161 /* For fields not not tracking in the in-memory inode,
5162 * initialise them to zero for new inodes. */
5163 if (ext4_test_inode_state(inode
, EXT4_STATE_NEW
))
5164 memset(raw_inode
, 0, EXT4_SB(inode
->i_sb
)->s_inode_size
);
5166 ext4_get_inode_flags(ei
);
5167 raw_inode
->i_mode
= cpu_to_le16(inode
->i_mode
);
5168 if (!(test_opt(inode
->i_sb
, NO_UID32
))) {
5169 raw_inode
->i_uid_low
= cpu_to_le16(low_16_bits(inode
->i_uid
));
5170 raw_inode
->i_gid_low
= cpu_to_le16(low_16_bits(inode
->i_gid
));
5172 * Fix up interoperability with old kernels. Otherwise, old inodes get
5173 * re-used with the upper 16 bits of the uid/gid intact
5176 raw_inode
->i_uid_high
=
5177 cpu_to_le16(high_16_bits(inode
->i_uid
));
5178 raw_inode
->i_gid_high
=
5179 cpu_to_le16(high_16_bits(inode
->i_gid
));
5181 raw_inode
->i_uid_high
= 0;
5182 raw_inode
->i_gid_high
= 0;
5185 raw_inode
->i_uid_low
=
5186 cpu_to_le16(fs_high2lowuid(inode
->i_uid
));
5187 raw_inode
->i_gid_low
=
5188 cpu_to_le16(fs_high2lowgid(inode
->i_gid
));
5189 raw_inode
->i_uid_high
= 0;
5190 raw_inode
->i_gid_high
= 0;
5192 raw_inode
->i_links_count
= cpu_to_le16(inode
->i_nlink
);
5194 EXT4_INODE_SET_XTIME(i_ctime
, inode
, raw_inode
);
5195 EXT4_INODE_SET_XTIME(i_mtime
, inode
, raw_inode
);
5196 EXT4_INODE_SET_XTIME(i_atime
, inode
, raw_inode
);
5197 EXT4_EINODE_SET_XTIME(i_crtime
, ei
, raw_inode
);
5199 if (ext4_inode_blocks_set(handle
, raw_inode
, ei
))
5201 raw_inode
->i_dtime
= cpu_to_le32(ei
->i_dtime
);
5202 raw_inode
->i_flags
= cpu_to_le32(ei
->i_flags
);
5203 if (EXT4_SB(inode
->i_sb
)->s_es
->s_creator_os
!=
5204 cpu_to_le32(EXT4_OS_HURD
))
5205 raw_inode
->i_file_acl_high
=
5206 cpu_to_le16(ei
->i_file_acl
>> 32);
5207 raw_inode
->i_file_acl_lo
= cpu_to_le32(ei
->i_file_acl
);
5208 ext4_isize_set(raw_inode
, ei
->i_disksize
);
5209 if (ei
->i_disksize
> 0x7fffffffULL
) {
5210 struct super_block
*sb
= inode
->i_sb
;
5211 if (!EXT4_HAS_RO_COMPAT_FEATURE(sb
,
5212 EXT4_FEATURE_RO_COMPAT_LARGE_FILE
) ||
5213 EXT4_SB(sb
)->s_es
->s_rev_level
==
5214 cpu_to_le32(EXT4_GOOD_OLD_REV
)) {
5215 /* If this is the first large file
5216 * created, add a flag to the superblock.
5218 err
= ext4_journal_get_write_access(handle
,
5219 EXT4_SB(sb
)->s_sbh
);
5222 ext4_update_dynamic_rev(sb
);
5223 EXT4_SET_RO_COMPAT_FEATURE(sb
,
5224 EXT4_FEATURE_RO_COMPAT_LARGE_FILE
);
5226 ext4_handle_sync(handle
);
5227 err
= ext4_handle_dirty_metadata(handle
, NULL
,
5228 EXT4_SB(sb
)->s_sbh
);
5231 raw_inode
->i_generation
= cpu_to_le32(inode
->i_generation
);
5232 if (S_ISCHR(inode
->i_mode
) || S_ISBLK(inode
->i_mode
)) {
5233 if (old_valid_dev(inode
->i_rdev
)) {
5234 raw_inode
->i_block
[0] =
5235 cpu_to_le32(old_encode_dev(inode
->i_rdev
));
5236 raw_inode
->i_block
[1] = 0;
5238 raw_inode
->i_block
[0] = 0;
5239 raw_inode
->i_block
[1] =
5240 cpu_to_le32(new_encode_dev(inode
->i_rdev
));
5241 raw_inode
->i_block
[2] = 0;
5244 for (block
= 0; block
< EXT4_N_BLOCKS
; block
++)
5245 raw_inode
->i_block
[block
] = ei
->i_data
[block
];
5247 raw_inode
->i_disk_version
= cpu_to_le32(inode
->i_version
);
5248 if (ei
->i_extra_isize
) {
5249 if (EXT4_FITS_IN_INODE(raw_inode
, ei
, i_version_hi
))
5250 raw_inode
->i_version_hi
=
5251 cpu_to_le32(inode
->i_version
>> 32);
5252 raw_inode
->i_extra_isize
= cpu_to_le16(ei
->i_extra_isize
);
5255 BUFFER_TRACE(bh
, "call ext4_handle_dirty_metadata");
5256 rc
= ext4_handle_dirty_metadata(handle
, NULL
, bh
);
5259 ext4_clear_inode_state(inode
, EXT4_STATE_NEW
);
5261 ext4_update_inode_fsync_trans(handle
, inode
, 0);
5264 ext4_std_error(inode
->i_sb
, err
);
5269 * ext4_write_inode()
5271 * We are called from a few places:
5273 * - Within generic_file_write() for O_SYNC files.
5274 * Here, there will be no transaction running. We wait for any running
5275 * trasnaction to commit.
5277 * - Within sys_sync(), kupdate and such.
5278 * We wait on commit, if tol to.
5280 * - Within prune_icache() (PF_MEMALLOC == true)
5281 * Here we simply return. We can't afford to block kswapd on the
5284 * In all cases it is actually safe for us to return without doing anything,
5285 * because the inode has been copied into a raw inode buffer in
5286 * ext4_mark_inode_dirty(). This is a correctness thing for O_SYNC and for
5289 * Note that we are absolutely dependent upon all inode dirtiers doing the
5290 * right thing: they *must* call mark_inode_dirty() after dirtying info in
5291 * which we are interested.
5293 * It would be a bug for them to not do this. The code:
5295 * mark_inode_dirty(inode)
5297 * inode->i_size = expr;
5299 * is in error because a kswapd-driven write_inode() could occur while
5300 * `stuff()' is running, and the new i_size will be lost. Plus the inode
5301 * will no longer be on the superblock's dirty inode list.
5303 int ext4_write_inode(struct inode
*inode
, struct writeback_control
*wbc
)
5307 if (current
->flags
& PF_MEMALLOC
)
5310 if (EXT4_SB(inode
->i_sb
)->s_journal
) {
5311 if (ext4_journal_current_handle()) {
5312 jbd_debug(1, "called recursively, non-PF_MEMALLOC!\n");
5317 if (wbc
->sync_mode
!= WB_SYNC_ALL
)
5320 err
= ext4_force_commit(inode
->i_sb
);
5322 struct ext4_iloc iloc
;
5324 err
= __ext4_get_inode_loc(inode
, &iloc
, 0);
5327 if (wbc
->sync_mode
== WB_SYNC_ALL
)
5328 sync_dirty_buffer(iloc
.bh
);
5329 if (buffer_req(iloc
.bh
) && !buffer_uptodate(iloc
.bh
)) {
5330 EXT4_ERROR_INODE_BLOCK(inode
, iloc
.bh
->b_blocknr
,
5331 "IO error syncing inode");
5342 * Called from notify_change.
5344 * We want to trap VFS attempts to truncate the file as soon as
5345 * possible. In particular, we want to make sure that when the VFS
5346 * shrinks i_size, we put the inode on the orphan list and modify
5347 * i_disksize immediately, so that during the subsequent flushing of
5348 * dirty pages and freeing of disk blocks, we can guarantee that any
5349 * commit will leave the blocks being flushed in an unused state on
5350 * disk. (On recovery, the inode will get truncated and the blocks will
5351 * be freed, so we have a strong guarantee that no future commit will
5352 * leave these blocks visible to the user.)
5354 * Another thing we have to assure is that if we are in ordered mode
5355 * and inode is still attached to the committing transaction, we must
5356 * we start writeout of all the dirty pages which are being truncated.
5357 * This way we are sure that all the data written in the previous
5358 * transaction are already on disk (truncate waits for pages under
5361 * Called with inode->i_mutex down.
5363 int ext4_setattr(struct dentry
*dentry
, struct iattr
*attr
)
5365 struct inode
*inode
= dentry
->d_inode
;
5367 const unsigned int ia_valid
= attr
->ia_valid
;
5369 error
= inode_change_ok(inode
, attr
);
5373 if (is_quota_modification(inode
, attr
))
5374 dquot_initialize(inode
);
5375 if ((ia_valid
& ATTR_UID
&& attr
->ia_uid
!= inode
->i_uid
) ||
5376 (ia_valid
& ATTR_GID
&& attr
->ia_gid
!= inode
->i_gid
)) {
5379 /* (user+group)*(old+new) structure, inode write (sb,
5380 * inode block, ? - but truncate inode update has it) */
5381 handle
= ext4_journal_start(inode
, (EXT4_MAXQUOTAS_INIT_BLOCKS(inode
->i_sb
)+
5382 EXT4_MAXQUOTAS_DEL_BLOCKS(inode
->i_sb
))+3);
5383 if (IS_ERR(handle
)) {
5384 error
= PTR_ERR(handle
);
5387 error
= dquot_transfer(inode
, attr
);
5389 ext4_journal_stop(handle
);
5392 /* Update corresponding info in inode so that everything is in
5393 * one transaction */
5394 if (attr
->ia_valid
& ATTR_UID
)
5395 inode
->i_uid
= attr
->ia_uid
;
5396 if (attr
->ia_valid
& ATTR_GID
)
5397 inode
->i_gid
= attr
->ia_gid
;
5398 error
= ext4_mark_inode_dirty(handle
, inode
);
5399 ext4_journal_stop(handle
);
5402 if (attr
->ia_valid
& ATTR_SIZE
) {
5403 if (!(ext4_test_inode_flag(inode
, EXT4_INODE_EXTENTS
))) {
5404 struct ext4_sb_info
*sbi
= EXT4_SB(inode
->i_sb
);
5406 if (attr
->ia_size
> sbi
->s_bitmap_maxbytes
)
5411 if (S_ISREG(inode
->i_mode
) &&
5412 attr
->ia_valid
& ATTR_SIZE
&&
5413 (attr
->ia_size
< inode
->i_size
||
5414 (ext4_test_inode_flag(inode
, EXT4_INODE_EOFBLOCKS
)))) {
5417 handle
= ext4_journal_start(inode
, 3);
5418 if (IS_ERR(handle
)) {
5419 error
= PTR_ERR(handle
);
5423 error
= ext4_orphan_add(handle
, inode
);
5424 EXT4_I(inode
)->i_disksize
= attr
->ia_size
;
5425 rc
= ext4_mark_inode_dirty(handle
, inode
);
5428 ext4_journal_stop(handle
);
5430 if (ext4_should_order_data(inode
)) {
5431 error
= ext4_begin_ordered_truncate(inode
,
5434 /* Do as much error cleanup as possible */
5435 handle
= ext4_journal_start(inode
, 3);
5436 if (IS_ERR(handle
)) {
5437 ext4_orphan_del(NULL
, inode
);
5440 ext4_orphan_del(handle
, inode
);
5441 ext4_journal_stop(handle
);
5445 /* ext4_truncate will clear the flag */
5446 if ((ext4_test_inode_flag(inode
, EXT4_INODE_EOFBLOCKS
)))
5447 ext4_truncate(inode
);
5450 if ((attr
->ia_valid
& ATTR_SIZE
) &&
5451 attr
->ia_size
!= i_size_read(inode
))
5452 rc
= vmtruncate(inode
, attr
->ia_size
);
5455 setattr_copy(inode
, attr
);
5456 mark_inode_dirty(inode
);
5460 * If the call to ext4_truncate failed to get a transaction handle at
5461 * all, we need to clean up the in-core orphan list manually.
5464 ext4_orphan_del(NULL
, inode
);
5466 if (!rc
&& (ia_valid
& ATTR_MODE
))
5467 rc
= ext4_acl_chmod(inode
);
5470 ext4_std_error(inode
->i_sb
, error
);
5476 int ext4_getattr(struct vfsmount
*mnt
, struct dentry
*dentry
,
5479 struct inode
*inode
;
5480 unsigned long delalloc_blocks
;
5482 inode
= dentry
->d_inode
;
5483 generic_fillattr(inode
, stat
);
5486 * We can't update i_blocks if the block allocation is delayed
5487 * otherwise in the case of system crash before the real block
5488 * allocation is done, we will have i_blocks inconsistent with
5489 * on-disk file blocks.
5490 * We always keep i_blocks updated together with real
5491 * allocation. But to not confuse with user, stat
5492 * will return the blocks that include the delayed allocation
5493 * blocks for this file.
5495 spin_lock(&EXT4_I(inode
)->i_block_reservation_lock
);
5496 delalloc_blocks
= EXT4_I(inode
)->i_reserved_data_blocks
;
5497 spin_unlock(&EXT4_I(inode
)->i_block_reservation_lock
);
5499 stat
->blocks
+= (delalloc_blocks
<< inode
->i_sb
->s_blocksize_bits
)>>9;
5503 static int ext4_indirect_trans_blocks(struct inode
*inode
, int nrblocks
,
5508 /* if nrblocks are contiguous */
5511 * With N contiguous data blocks, it need at most
5512 * N/EXT4_ADDR_PER_BLOCK(inode->i_sb) indirect blocks
5513 * 2 dindirect blocks
5516 indirects
= nrblocks
/ EXT4_ADDR_PER_BLOCK(inode
->i_sb
);
5517 return indirects
+ 3;
5520 * if nrblocks are not contiguous, worse case, each block touch
5521 * a indirect block, and each indirect block touch a double indirect
5522 * block, plus a triple indirect block
5524 indirects
= nrblocks
* 2 + 1;
5528 static int ext4_index_trans_blocks(struct inode
*inode
, int nrblocks
, int chunk
)
5530 if (!(ext4_test_inode_flag(inode
, EXT4_INODE_EXTENTS
)))
5531 return ext4_indirect_trans_blocks(inode
, nrblocks
, chunk
);
5532 return ext4_ext_index_trans_blocks(inode
, nrblocks
, chunk
);
5536 * Account for index blocks, block groups bitmaps and block group
5537 * descriptor blocks if modify datablocks and index blocks
5538 * worse case, the indexs blocks spread over different block groups
5540 * If datablocks are discontiguous, they are possible to spread over
5541 * different block groups too. If they are contiuguous, with flexbg,
5542 * they could still across block group boundary.
5544 * Also account for superblock, inode, quota and xattr blocks
5546 int ext4_meta_trans_blocks(struct inode
*inode
, int nrblocks
, int chunk
)
5548 ext4_group_t groups
, ngroups
= ext4_get_groups_count(inode
->i_sb
);
5554 * How many index blocks need to touch to modify nrblocks?
5555 * The "Chunk" flag indicating whether the nrblocks is
5556 * physically contiguous on disk
5558 * For Direct IO and fallocate, they calls get_block to allocate
5559 * one single extent at a time, so they could set the "Chunk" flag
5561 idxblocks
= ext4_index_trans_blocks(inode
, nrblocks
, chunk
);
5566 * Now let's see how many group bitmaps and group descriptors need
5576 if (groups
> ngroups
)
5578 if (groups
> EXT4_SB(inode
->i_sb
)->s_gdb_count
)
5579 gdpblocks
= EXT4_SB(inode
->i_sb
)->s_gdb_count
;
5581 /* bitmaps and block group descriptor blocks */
5582 ret
+= groups
+ gdpblocks
;
5584 /* Blocks for super block, inode, quota and xattr blocks */
5585 ret
+= EXT4_META_TRANS_BLOCKS(inode
->i_sb
);
5591 * Calulate the total number of credits to reserve to fit
5592 * the modification of a single pages into a single transaction,
5593 * which may include multiple chunks of block allocations.
5595 * This could be called via ext4_write_begin()
5597 * We need to consider the worse case, when
5598 * one new block per extent.
5600 int ext4_writepage_trans_blocks(struct inode
*inode
)
5602 int bpp
= ext4_journal_blocks_per_page(inode
);
5605 ret
= ext4_meta_trans_blocks(inode
, bpp
, 0);
5607 /* Account for data blocks for journalled mode */
5608 if (ext4_should_journal_data(inode
))
5614 * Calculate the journal credits for a chunk of data modification.
5616 * This is called from DIO, fallocate or whoever calling
5617 * ext4_map_blocks() to map/allocate a chunk of contiguous disk blocks.
5619 * journal buffers for data blocks are not included here, as DIO
5620 * and fallocate do no need to journal data buffers.
5622 int ext4_chunk_trans_blocks(struct inode
*inode
, int nrblocks
)
5624 return ext4_meta_trans_blocks(inode
, nrblocks
, 1);
5628 * The caller must have previously called ext4_reserve_inode_write().
5629 * Give this, we know that the caller already has write access to iloc->bh.
5631 int ext4_mark_iloc_dirty(handle_t
*handle
,
5632 struct inode
*inode
, struct ext4_iloc
*iloc
)
5636 if (test_opt(inode
->i_sb
, I_VERSION
))
5637 inode_inc_iversion(inode
);
5639 /* the do_update_inode consumes one bh->b_count */
5642 /* ext4_do_update_inode() does jbd2_journal_dirty_metadata */
5643 err
= ext4_do_update_inode(handle
, inode
, iloc
);
5649 * On success, We end up with an outstanding reference count against
5650 * iloc->bh. This _must_ be cleaned up later.
5654 ext4_reserve_inode_write(handle_t
*handle
, struct inode
*inode
,
5655 struct ext4_iloc
*iloc
)
5659 err
= ext4_get_inode_loc(inode
, iloc
);
5661 BUFFER_TRACE(iloc
->bh
, "get_write_access");
5662 err
= ext4_journal_get_write_access(handle
, iloc
->bh
);
5668 ext4_std_error(inode
->i_sb
, err
);
5673 * Expand an inode by new_extra_isize bytes.
5674 * Returns 0 on success or negative error number on failure.
5676 static int ext4_expand_extra_isize(struct inode
*inode
,
5677 unsigned int new_extra_isize
,
5678 struct ext4_iloc iloc
,
5681 struct ext4_inode
*raw_inode
;
5682 struct ext4_xattr_ibody_header
*header
;
5684 if (EXT4_I(inode
)->i_extra_isize
>= new_extra_isize
)
5687 raw_inode
= ext4_raw_inode(&iloc
);
5689 header
= IHDR(inode
, raw_inode
);
5691 /* No extended attributes present */
5692 if (!ext4_test_inode_state(inode
, EXT4_STATE_XATTR
) ||
5693 header
->h_magic
!= cpu_to_le32(EXT4_XATTR_MAGIC
)) {
5694 memset((void *)raw_inode
+ EXT4_GOOD_OLD_INODE_SIZE
, 0,
5696 EXT4_I(inode
)->i_extra_isize
= new_extra_isize
;
5700 /* try to expand with EAs present */
5701 return ext4_expand_extra_isize_ea(inode
, new_extra_isize
,
5706 * What we do here is to mark the in-core inode as clean with respect to inode
5707 * dirtiness (it may still be data-dirty).
5708 * This means that the in-core inode may be reaped by prune_icache
5709 * without having to perform any I/O. This is a very good thing,
5710 * because *any* task may call prune_icache - even ones which
5711 * have a transaction open against a different journal.
5713 * Is this cheating? Not really. Sure, we haven't written the
5714 * inode out, but prune_icache isn't a user-visible syncing function.
5715 * Whenever the user wants stuff synced (sys_sync, sys_msync, sys_fsync)
5716 * we start and wait on commits.
5718 * Is this efficient/effective? Well, we're being nice to the system
5719 * by cleaning up our inodes proactively so they can be reaped
5720 * without I/O. But we are potentially leaving up to five seconds'
5721 * worth of inodes floating about which prune_icache wants us to
5722 * write out. One way to fix that would be to get prune_icache()
5723 * to do a write_super() to free up some memory. It has the desired
5726 int ext4_mark_inode_dirty(handle_t
*handle
, struct inode
*inode
)
5728 struct ext4_iloc iloc
;
5729 struct ext4_sb_info
*sbi
= EXT4_SB(inode
->i_sb
);
5730 static unsigned int mnt_count
;
5734 err
= ext4_reserve_inode_write(handle
, inode
, &iloc
);
5735 if (ext4_handle_valid(handle
) &&
5736 EXT4_I(inode
)->i_extra_isize
< sbi
->s_want_extra_isize
&&
5737 !ext4_test_inode_state(inode
, EXT4_STATE_NO_EXPAND
)) {
5739 * We need extra buffer credits since we may write into EA block
5740 * with this same handle. If journal_extend fails, then it will
5741 * only result in a minor loss of functionality for that inode.
5742 * If this is felt to be critical, then e2fsck should be run to
5743 * force a large enough s_min_extra_isize.
5745 if ((jbd2_journal_extend(handle
,
5746 EXT4_DATA_TRANS_BLOCKS(inode
->i_sb
))) == 0) {
5747 ret
= ext4_expand_extra_isize(inode
,
5748 sbi
->s_want_extra_isize
,
5751 ext4_set_inode_state(inode
,
5752 EXT4_STATE_NO_EXPAND
);
5754 le16_to_cpu(sbi
->s_es
->s_mnt_count
)) {
5755 ext4_warning(inode
->i_sb
,
5756 "Unable to expand inode %lu. Delete"
5757 " some EAs or run e2fsck.",
5760 le16_to_cpu(sbi
->s_es
->s_mnt_count
);
5766 err
= ext4_mark_iloc_dirty(handle
, inode
, &iloc
);
5771 * ext4_dirty_inode() is called from __mark_inode_dirty()
5773 * We're really interested in the case where a file is being extended.
5774 * i_size has been changed by generic_commit_write() and we thus need
5775 * to include the updated inode in the current transaction.
5777 * Also, dquot_alloc_block() will always dirty the inode when blocks
5778 * are allocated to the file.
5780 * If the inode is marked synchronous, we don't honour that here - doing
5781 * so would cause a commit on atime updates, which we don't bother doing.
5782 * We handle synchronous inodes at the highest possible level.
5784 void ext4_dirty_inode(struct inode
*inode
)
5788 handle
= ext4_journal_start(inode
, 2);
5792 ext4_mark_inode_dirty(handle
, inode
);
5794 ext4_journal_stop(handle
);
5801 * Bind an inode's backing buffer_head into this transaction, to prevent
5802 * it from being flushed to disk early. Unlike
5803 * ext4_reserve_inode_write, this leaves behind no bh reference and
5804 * returns no iloc structure, so the caller needs to repeat the iloc
5805 * lookup to mark the inode dirty later.
5807 static int ext4_pin_inode(handle_t
*handle
, struct inode
*inode
)
5809 struct ext4_iloc iloc
;
5813 err
= ext4_get_inode_loc(inode
, &iloc
);
5815 BUFFER_TRACE(iloc
.bh
, "get_write_access");
5816 err
= jbd2_journal_get_write_access(handle
, iloc
.bh
);
5818 err
= ext4_handle_dirty_metadata(handle
,
5824 ext4_std_error(inode
->i_sb
, err
);
5829 int ext4_change_inode_journal_flag(struct inode
*inode
, int val
)
5836 * We have to be very careful here: changing a data block's
5837 * journaling status dynamically is dangerous. If we write a
5838 * data block to the journal, change the status and then delete
5839 * that block, we risk forgetting to revoke the old log record
5840 * from the journal and so a subsequent replay can corrupt data.
5841 * So, first we make sure that the journal is empty and that
5842 * nobody is changing anything.
5845 journal
= EXT4_JOURNAL(inode
);
5848 if (is_journal_aborted(journal
))
5851 jbd2_journal_lock_updates(journal
);
5852 jbd2_journal_flush(journal
);
5855 * OK, there are no updates running now, and all cached data is
5856 * synced to disk. We are now in a completely consistent state
5857 * which doesn't have anything in the journal, and we know that
5858 * no filesystem updates are running, so it is safe to modify
5859 * the inode's in-core data-journaling state flag now.
5863 ext4_set_inode_flag(inode
, EXT4_INODE_JOURNAL_DATA
);
5865 ext4_clear_inode_flag(inode
, EXT4_INODE_JOURNAL_DATA
);
5866 ext4_set_aops(inode
);
5868 jbd2_journal_unlock_updates(journal
);
5870 /* Finally we can mark the inode as dirty. */
5872 handle
= ext4_journal_start(inode
, 1);
5874 return PTR_ERR(handle
);
5876 err
= ext4_mark_inode_dirty(handle
, inode
);
5877 ext4_handle_sync(handle
);
5878 ext4_journal_stop(handle
);
5879 ext4_std_error(inode
->i_sb
, err
);
5884 static int ext4_bh_unmapped(handle_t
*handle
, struct buffer_head
*bh
)
5886 return !buffer_mapped(bh
);
5889 int ext4_page_mkwrite(struct vm_area_struct
*vma
, struct vm_fault
*vmf
)
5891 struct page
*page
= vmf
->page
;
5896 struct file
*file
= vma
->vm_file
;
5897 struct inode
*inode
= file
->f_path
.dentry
->d_inode
;
5898 struct address_space
*mapping
= inode
->i_mapping
;
5901 * Get i_alloc_sem to stop truncates messing with the inode. We cannot
5902 * get i_mutex because we are already holding mmap_sem.
5904 down_read(&inode
->i_alloc_sem
);
5905 size
= i_size_read(inode
);
5906 if (page
->mapping
!= mapping
|| size
<= page_offset(page
)
5907 || !PageUptodate(page
)) {
5908 /* page got truncated from under us? */
5912 if (PageMappedToDisk(page
))
5915 if (page
->index
== size
>> PAGE_CACHE_SHIFT
)
5916 len
= size
& ~PAGE_CACHE_MASK
;
5918 len
= PAGE_CACHE_SIZE
;
5922 * return if we have all the buffers mapped. This avoid
5923 * the need to call write_begin/write_end which does a
5924 * journal_start/journal_stop which can block and take
5927 if (page_has_buffers(page
)) {
5928 if (!walk_page_buffers(NULL
, page_buffers(page
), 0, len
, NULL
,
5929 ext4_bh_unmapped
)) {
5936 * OK, we need to fill the hole... Do write_begin write_end
5937 * to do block allocation/reservation.We are not holding
5938 * inode.i__mutex here. That allow * parallel write_begin,
5939 * write_end call. lock_page prevent this from happening
5940 * on the same page though
5942 ret
= mapping
->a_ops
->write_begin(file
, mapping
, page_offset(page
),
5943 len
, AOP_FLAG_UNINTERRUPTIBLE
, &page
, &fsdata
);
5946 ret
= mapping
->a_ops
->write_end(file
, mapping
, page_offset(page
),
5947 len
, len
, page
, fsdata
);
5953 ret
= VM_FAULT_SIGBUS
;
5954 up_read(&inode
->i_alloc_sem
);