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/file.c
13 * Copyright (C) 1991, 1992 Linus Torvalds
15 * ext4 fs regular file handling primitives
17 * 64-bit file support on 64-bit platforms by Jakub Jelinek
18 * (jj@sunsite.ms.mff.cuni.cz)
21 #include <linux/time.h>
23 #include <linux/jbd2.h>
24 #include <linux/mount.h>
25 #include <linux/path.h>
26 #include <linux/quotaops.h>
27 #include <linux/pagevec.h>
28 #include <linux/uio.h>
30 #include "ext4_jbd2.h"
35 * Called when an inode is released. Note that this is different
36 * from ext4_file_open: open gets called at every open, but release
37 * gets called only when /all/ the files are closed.
39 static int ext4_release_file(struct inode
*inode
, struct file
*filp
)
41 if (ext4_test_inode_state(inode
, EXT4_STATE_DA_ALLOC_CLOSE
)) {
42 ext4_alloc_da_blocks(inode
);
43 ext4_clear_inode_state(inode
, EXT4_STATE_DA_ALLOC_CLOSE
);
45 /* if we are the last writer on the inode, drop the block reservation */
46 if ((filp
->f_mode
& FMODE_WRITE
) &&
47 (atomic_read(&inode
->i_writecount
) == 1) &&
48 !EXT4_I(inode
)->i_reserved_data_blocks
)
50 down_write(&EXT4_I(inode
)->i_data_sem
);
51 ext4_discard_preallocations(inode
);
52 up_write(&EXT4_I(inode
)->i_data_sem
);
54 if (is_dx(inode
) && filp
->private_data
)
55 ext4_htree_free_dir_info(filp
->private_data
);
60 static void ext4_unwritten_wait(struct inode
*inode
)
62 wait_queue_head_t
*wq
= ext4_ioend_wq(inode
);
64 wait_event(*wq
, (atomic_read(&EXT4_I(inode
)->i_unwritten
) == 0));
68 * This tests whether the IO in question is block-aligned or not.
69 * Ext4 utilizes unwritten extents when hole-filling during direct IO, and they
70 * are converted to written only after the IO is complete. Until they are
71 * mapped, these blocks appear as holes, so dio_zero_block() will assume that
72 * it needs to zero out portions of the start and/or end block. If 2 AIO
73 * threads are at work on the same unwritten block, they must be synchronized
74 * or one thread will zero the other's data, causing corruption.
77 ext4_unaligned_aio(struct inode
*inode
, struct iov_iter
*from
, loff_t pos
)
79 struct super_block
*sb
= inode
->i_sb
;
80 int blockmask
= sb
->s_blocksize
- 1;
82 if (pos
>= i_size_read(inode
))
85 if ((pos
| iov_iter_alignment(from
)) & blockmask
)
92 ext4_file_write_iter(struct kiocb
*iocb
, struct iov_iter
*from
)
94 struct file
*file
= iocb
->ki_filp
;
95 struct inode
*inode
= file_inode(iocb
->ki_filp
);
96 struct mutex
*aio_mutex
= NULL
;
98 int o_direct
= iocb
->ki_flags
& IOCB_DIRECT
;
103 * Unaligned direct AIO must be serialized; see comment above
104 * In the case of O_APPEND, assume that we must always serialize
107 ext4_test_inode_flag(inode
, EXT4_INODE_EXTENTS
) &&
108 !is_sync_kiocb(iocb
) &&
109 (iocb
->ki_flags
& IOCB_APPEND
||
110 ext4_unaligned_aio(inode
, from
, iocb
->ki_pos
))) {
111 aio_mutex
= ext4_aio_mutex(inode
);
112 mutex_lock(aio_mutex
);
113 ext4_unwritten_wait(inode
);
116 mutex_lock(&inode
->i_mutex
);
117 ret
= generic_write_checks(iocb
, from
);
122 * If we have encountered a bitmap-format file, the size limit
123 * is smaller than s_maxbytes, which is for extent-mapped files.
125 if (!(ext4_test_inode_flag(inode
, EXT4_INODE_EXTENTS
))) {
126 struct ext4_sb_info
*sbi
= EXT4_SB(inode
->i_sb
);
128 if (iocb
->ki_pos
>= sbi
->s_bitmap_maxbytes
) {
132 iov_iter_truncate(from
, sbi
->s_bitmap_maxbytes
- iocb
->ki_pos
);
135 iocb
->private = &overwrite
;
137 size_t length
= iov_iter_count(from
);
138 loff_t pos
= iocb
->ki_pos
;
139 blk_start_plug(&plug
);
141 /* check whether we do a DIO overwrite or not */
142 if (ext4_should_dioread_nolock(inode
) && !aio_mutex
&&
143 !file
->f_mapping
->nrpages
&& pos
+ length
<= i_size_read(inode
)) {
144 struct ext4_map_blocks map
;
145 unsigned int blkbits
= inode
->i_blkbits
;
148 map
.m_lblk
= pos
>> blkbits
;
149 map
.m_len
= (EXT4_BLOCK_ALIGN(pos
+ length
, blkbits
) >> blkbits
)
153 err
= ext4_map_blocks(NULL
, inode
, &map
, 0);
155 * 'err==len' means that all of blocks has
156 * been preallocated no matter they are
157 * initialized or not. For excluding
158 * unwritten extents, we need to check
159 * m_flags. There are two conditions that
160 * indicate for initialized extents. 1) If we
161 * hit extent cache, EXT4_MAP_MAPPED flag is
162 * returned; 2) If we do a real lookup,
163 * non-flags are returned. So we should check
164 * these two conditions.
166 if (err
== len
&& (map
.m_flags
& EXT4_MAP_MAPPED
))
171 ret
= __generic_file_write_iter(iocb
, from
);
172 mutex_unlock(&inode
->i_mutex
);
177 err
= generic_write_sync(file
, iocb
->ki_pos
- ret
, ret
);
182 blk_finish_plug(&plug
);
185 mutex_unlock(aio_mutex
);
189 mutex_unlock(&inode
->i_mutex
);
191 mutex_unlock(aio_mutex
);
196 static int ext4_dax_fault(struct vm_area_struct
*vma
, struct vm_fault
*vmf
)
198 return dax_fault(vma
, vmf
, ext4_get_block
);
199 /* Is this the right get_block? */
202 static int ext4_dax_mkwrite(struct vm_area_struct
*vma
, struct vm_fault
*vmf
)
204 return dax_mkwrite(vma
, vmf
, ext4_get_block
);
207 static const struct vm_operations_struct ext4_dax_vm_ops
= {
208 .fault
= ext4_dax_fault
,
209 .page_mkwrite
= ext4_dax_mkwrite
,
212 #define ext4_dax_vm_ops ext4_file_vm_ops
215 static const struct vm_operations_struct ext4_file_vm_ops
= {
216 .fault
= filemap_fault
,
217 .map_pages
= filemap_map_pages
,
218 .page_mkwrite
= ext4_page_mkwrite
,
221 static int ext4_file_mmap(struct file
*file
, struct vm_area_struct
*vma
)
224 if (IS_DAX(file_inode(file
))) {
225 vma
->vm_ops
= &ext4_dax_vm_ops
;
226 vma
->vm_flags
|= VM_MIXEDMAP
;
228 vma
->vm_ops
= &ext4_file_vm_ops
;
233 static int ext4_file_open(struct inode
* inode
, struct file
* filp
)
235 struct super_block
*sb
= inode
->i_sb
;
236 struct ext4_sb_info
*sbi
= EXT4_SB(inode
->i_sb
);
237 struct vfsmount
*mnt
= filp
->f_path
.mnt
;
241 if (unlikely(!(sbi
->s_mount_flags
& EXT4_MF_MNTDIR_SAMPLED
) &&
242 !(sb
->s_flags
& MS_RDONLY
))) {
243 sbi
->s_mount_flags
|= EXT4_MF_MNTDIR_SAMPLED
;
245 * Sample where the filesystem has been mounted and
246 * store it in the superblock for sysadmin convenience
247 * when trying to sort through large numbers of block
248 * devices or filesystem images.
250 memset(buf
, 0, sizeof(buf
));
252 path
.dentry
= mnt
->mnt_root
;
253 cp
= d_path(&path
, buf
, sizeof(buf
));
258 handle
= ext4_journal_start_sb(sb
, EXT4_HT_MISC
, 1);
260 return PTR_ERR(handle
);
261 BUFFER_TRACE(sbi
->s_sbh
, "get_write_access");
262 err
= ext4_journal_get_write_access(handle
, sbi
->s_sbh
);
264 ext4_journal_stop(handle
);
267 strlcpy(sbi
->s_es
->s_last_mounted
, cp
,
268 sizeof(sbi
->s_es
->s_last_mounted
));
269 ext4_handle_dirty_super(handle
, sb
);
270 ext4_journal_stop(handle
);
274 * Set up the jbd2_inode if we are opening the inode for
275 * writing and the journal is present
277 if (filp
->f_mode
& FMODE_WRITE
) {
278 int ret
= ext4_inode_attach_jinode(inode
);
282 return dquot_file_open(inode
, filp
);
286 * Here we use ext4_map_blocks() to get a block mapping for a extent-based
287 * file rather than ext4_ext_walk_space() because we can introduce
288 * SEEK_DATA/SEEK_HOLE for block-mapped and extent-mapped file at the same
289 * function. When extent status tree has been fully implemented, it will
290 * track all extent status for a file and we can directly use it to
291 * retrieve the offset for SEEK_DATA/SEEK_HOLE.
295 * When we retrieve the offset for SEEK_DATA/SEEK_HOLE, we would need to
296 * lookup page cache to check whether or not there has some data between
297 * [startoff, endoff] because, if this range contains an unwritten extent,
298 * we determine this extent as a data or a hole according to whether the
299 * page cache has data or not.
301 static int ext4_find_unwritten_pgoff(struct inode
*inode
,
303 struct ext4_map_blocks
*map
,
307 unsigned int blkbits
;
315 blkbits
= inode
->i_sb
->s_blocksize_bits
;
318 endoff
= (loff_t
)(map
->m_lblk
+ map
->m_len
) << blkbits
;
320 index
= startoff
>> PAGE_CACHE_SHIFT
;
321 end
= endoff
>> PAGE_CACHE_SHIFT
;
323 pagevec_init(&pvec
, 0);
326 unsigned long nr_pages
;
328 num
= min_t(pgoff_t
, end
- index
, PAGEVEC_SIZE
);
329 nr_pages
= pagevec_lookup(&pvec
, inode
->i_mapping
, index
,
332 if (whence
== SEEK_DATA
)
335 BUG_ON(whence
!= SEEK_HOLE
);
337 * If this is the first time to go into the loop and
338 * offset is not beyond the end offset, it will be a
339 * hole at this offset
341 if (lastoff
== startoff
|| lastoff
< endoff
)
347 * If this is the first time to go into the loop and
348 * offset is smaller than the first page offset, it will be a
349 * hole at this offset.
351 if (lastoff
== startoff
&& whence
== SEEK_HOLE
&&
352 lastoff
< page_offset(pvec
.pages
[0])) {
357 for (i
= 0; i
< nr_pages
; i
++) {
358 struct page
*page
= pvec
.pages
[i
];
359 struct buffer_head
*bh
, *head
;
362 * If the current offset is not beyond the end of given
363 * range, it will be a hole.
365 if (lastoff
< endoff
&& whence
== SEEK_HOLE
&&
374 if (unlikely(page
->mapping
!= inode
->i_mapping
)) {
379 if (!page_has_buffers(page
)) {
384 if (page_has_buffers(page
)) {
385 lastoff
= page_offset(page
);
386 bh
= head
= page_buffers(page
);
388 if (buffer_uptodate(bh
) ||
389 buffer_unwritten(bh
)) {
390 if (whence
== SEEK_DATA
)
393 if (whence
== SEEK_HOLE
)
397 *offset
= max_t(loff_t
,
402 lastoff
+= bh
->b_size
;
403 bh
= bh
->b_this_page
;
404 } while (bh
!= head
);
407 lastoff
= page_offset(page
) + PAGE_SIZE
;
412 * The no. of pages is less than our desired, that would be a
415 if (nr_pages
< num
&& whence
== SEEK_HOLE
) {
421 index
= pvec
.pages
[i
- 1]->index
+ 1;
422 pagevec_release(&pvec
);
423 } while (index
<= end
);
426 pagevec_release(&pvec
);
431 * ext4_seek_data() retrieves the offset for SEEK_DATA.
433 static loff_t
ext4_seek_data(struct file
*file
, loff_t offset
, loff_t maxsize
)
435 struct inode
*inode
= file
->f_mapping
->host
;
436 struct ext4_map_blocks map
;
437 struct extent_status es
;
438 ext4_lblk_t start
, last
, end
;
439 loff_t dataoff
, isize
;
443 mutex_lock(&inode
->i_mutex
);
445 isize
= i_size_read(inode
);
446 if (offset
>= isize
) {
447 mutex_unlock(&inode
->i_mutex
);
451 blkbits
= inode
->i_sb
->s_blocksize_bits
;
452 start
= offset
>> blkbits
;
454 end
= isize
>> blkbits
;
459 map
.m_len
= end
- last
+ 1;
460 ret
= ext4_map_blocks(NULL
, inode
, &map
, 0);
461 if (ret
> 0 && !(map
.m_flags
& EXT4_MAP_UNWRITTEN
)) {
463 dataoff
= (loff_t
)last
<< blkbits
;
468 * If there is a delay extent at this offset,
469 * it will be as a data.
471 ext4_es_find_delayed_extent_range(inode
, last
, last
, &es
);
472 if (es
.es_len
!= 0 && in_range(last
, es
.es_lblk
, es
.es_len
)) {
474 dataoff
= (loff_t
)last
<< blkbits
;
479 * If there is a unwritten extent at this offset,
480 * it will be as a data or a hole according to page
481 * cache that has data or not.
483 if (map
.m_flags
& EXT4_MAP_UNWRITTEN
) {
485 unwritten
= ext4_find_unwritten_pgoff(inode
, SEEK_DATA
,
492 dataoff
= (loff_t
)last
<< blkbits
;
493 } while (last
<= end
);
495 mutex_unlock(&inode
->i_mutex
);
500 return vfs_setpos(file
, dataoff
, maxsize
);
504 * ext4_seek_hole() retrieves the offset for SEEK_HOLE.
506 static loff_t
ext4_seek_hole(struct file
*file
, loff_t offset
, loff_t maxsize
)
508 struct inode
*inode
= file
->f_mapping
->host
;
509 struct ext4_map_blocks map
;
510 struct extent_status es
;
511 ext4_lblk_t start
, last
, end
;
512 loff_t holeoff
, isize
;
516 mutex_lock(&inode
->i_mutex
);
518 isize
= i_size_read(inode
);
519 if (offset
>= isize
) {
520 mutex_unlock(&inode
->i_mutex
);
524 blkbits
= inode
->i_sb
->s_blocksize_bits
;
525 start
= offset
>> blkbits
;
527 end
= isize
>> blkbits
;
532 map
.m_len
= end
- last
+ 1;
533 ret
= ext4_map_blocks(NULL
, inode
, &map
, 0);
534 if (ret
> 0 && !(map
.m_flags
& EXT4_MAP_UNWRITTEN
)) {
536 holeoff
= (loff_t
)last
<< blkbits
;
541 * If there is a delay extent at this offset,
542 * we will skip this extent.
544 ext4_es_find_delayed_extent_range(inode
, last
, last
, &es
);
545 if (es
.es_len
!= 0 && in_range(last
, es
.es_lblk
, es
.es_len
)) {
546 last
= es
.es_lblk
+ es
.es_len
;
547 holeoff
= (loff_t
)last
<< blkbits
;
552 * If there is a unwritten extent at this offset,
553 * it will be as a data or a hole according to page
554 * cache that has data or not.
556 if (map
.m_flags
& EXT4_MAP_UNWRITTEN
) {
558 unwritten
= ext4_find_unwritten_pgoff(inode
, SEEK_HOLE
,
562 holeoff
= (loff_t
)last
<< blkbits
;
569 } while (last
<= end
);
571 mutex_unlock(&inode
->i_mutex
);
576 return vfs_setpos(file
, holeoff
, maxsize
);
580 * ext4_llseek() handles both block-mapped and extent-mapped maxbytes values
581 * by calling generic_file_llseek_size() with the appropriate maxbytes
584 loff_t
ext4_llseek(struct file
*file
, loff_t offset
, int whence
)
586 struct inode
*inode
= file
->f_mapping
->host
;
589 if (!(ext4_test_inode_flag(inode
, EXT4_INODE_EXTENTS
)))
590 maxbytes
= EXT4_SB(inode
->i_sb
)->s_bitmap_maxbytes
;
592 maxbytes
= inode
->i_sb
->s_maxbytes
;
598 return generic_file_llseek_size(file
, offset
, whence
,
599 maxbytes
, i_size_read(inode
));
601 return ext4_seek_data(file
, offset
, maxbytes
);
603 return ext4_seek_hole(file
, offset
, maxbytes
);
609 const struct file_operations ext4_file_operations
= {
610 .llseek
= ext4_llseek
,
611 .read_iter
= generic_file_read_iter
,
612 .write_iter
= ext4_file_write_iter
,
613 .unlocked_ioctl
= ext4_ioctl
,
615 .compat_ioctl
= ext4_compat_ioctl
,
617 .mmap
= ext4_file_mmap
,
618 .open
= ext4_file_open
,
619 .release
= ext4_release_file
,
620 .fsync
= ext4_sync_file
,
621 .splice_read
= generic_file_splice_read
,
622 .splice_write
= iter_file_splice_write
,
623 .fallocate
= ext4_fallocate
,
627 const struct file_operations ext4_dax_file_operations
= {
628 .llseek
= ext4_llseek
,
629 .read_iter
= generic_file_read_iter
,
630 .write_iter
= ext4_file_write_iter
,
631 .unlocked_ioctl
= ext4_ioctl
,
633 .compat_ioctl
= ext4_compat_ioctl
,
635 .mmap
= ext4_file_mmap
,
636 .open
= ext4_file_open
,
637 .release
= ext4_release_file
,
638 .fsync
= ext4_sync_file
,
639 /* Splice not yet supported with DAX */
640 .fallocate
= ext4_fallocate
,
644 const struct inode_operations ext4_file_inode_operations
= {
645 .setattr
= ext4_setattr
,
646 .getattr
= ext4_getattr
,
647 .setxattr
= generic_setxattr
,
648 .getxattr
= generic_getxattr
,
649 .listxattr
= ext4_listxattr
,
650 .removexattr
= generic_removexattr
,
651 .get_acl
= ext4_get_acl
,
652 .set_acl
= ext4_set_acl
,
653 .fiemap
= ext4_fiemap
,