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/mount.h>
24 #include <linux/path.h>
25 #include <linux/dax.h>
26 #include <linux/quotaops.h>
27 #include <linux/pagevec.h>
28 #include <linux/uio.h>
30 #include "ext4_jbd2.h"
35 static ssize_t
ext4_dax_read_iter(struct kiocb
*iocb
, struct iov_iter
*to
)
37 struct inode
*inode
= file_inode(iocb
->ki_filp
);
40 if (!inode_trylock_shared(inode
)) {
41 if (iocb
->ki_flags
& IOCB_NOWAIT
)
43 inode_lock_shared(inode
);
46 * Recheck under inode lock - at this point we are sure it cannot
50 inode_unlock_shared(inode
);
51 /* Fallback to buffered IO in case we cannot support DAX */
52 return generic_file_read_iter(iocb
, to
);
54 ret
= dax_iomap_rw(iocb
, to
, &ext4_iomap_ops
);
55 inode_unlock_shared(inode
);
57 file_accessed(iocb
->ki_filp
);
62 static ssize_t
ext4_file_read_iter(struct kiocb
*iocb
, struct iov_iter
*to
)
64 if (unlikely(ext4_forced_shutdown(EXT4_SB(file_inode(iocb
->ki_filp
)->i_sb
))))
67 if (!iov_iter_count(to
))
68 return 0; /* skip atime */
71 if (IS_DAX(file_inode(iocb
->ki_filp
)))
72 return ext4_dax_read_iter(iocb
, to
);
74 return generic_file_read_iter(iocb
, to
);
78 * Called when an inode is released. Note that this is different
79 * from ext4_file_open: open gets called at every open, but release
80 * gets called only when /all/ the files are closed.
82 static int ext4_release_file(struct inode
*inode
, struct file
*filp
)
84 if (ext4_test_inode_state(inode
, EXT4_STATE_DA_ALLOC_CLOSE
)) {
85 ext4_alloc_da_blocks(inode
);
86 ext4_clear_inode_state(inode
, EXT4_STATE_DA_ALLOC_CLOSE
);
88 /* if we are the last writer on the inode, drop the block reservation */
89 if ((filp
->f_mode
& FMODE_WRITE
) &&
90 (atomic_read(&inode
->i_writecount
) == 1) &&
91 !EXT4_I(inode
)->i_reserved_data_blocks
)
93 down_write(&EXT4_I(inode
)->i_data_sem
);
94 ext4_discard_preallocations(inode
);
95 up_write(&EXT4_I(inode
)->i_data_sem
);
97 if (is_dx(inode
) && filp
->private_data
)
98 ext4_htree_free_dir_info(filp
->private_data
);
103 static void ext4_unwritten_wait(struct inode
*inode
)
105 wait_queue_head_t
*wq
= ext4_ioend_wq(inode
);
107 wait_event(*wq
, (atomic_read(&EXT4_I(inode
)->i_unwritten
) == 0));
111 * This tests whether the IO in question is block-aligned or not.
112 * Ext4 utilizes unwritten extents when hole-filling during direct IO, and they
113 * are converted to written only after the IO is complete. Until they are
114 * mapped, these blocks appear as holes, so dio_zero_block() will assume that
115 * it needs to zero out portions of the start and/or end block. If 2 AIO
116 * threads are at work on the same unwritten block, they must be synchronized
117 * or one thread will zero the other's data, causing corruption.
120 ext4_unaligned_aio(struct inode
*inode
, struct iov_iter
*from
, loff_t pos
)
122 struct super_block
*sb
= inode
->i_sb
;
123 int blockmask
= sb
->s_blocksize
- 1;
125 if (pos
>= i_size_read(inode
))
128 if ((pos
| iov_iter_alignment(from
)) & blockmask
)
134 /* Is IO overwriting allocated and initialized blocks? */
135 static bool ext4_overwrite_io(struct inode
*inode
, loff_t pos
, loff_t len
)
137 struct ext4_map_blocks map
;
138 unsigned int blkbits
= inode
->i_blkbits
;
141 if (pos
+ len
> i_size_read(inode
))
144 map
.m_lblk
= pos
>> blkbits
;
145 map
.m_len
= EXT4_MAX_BLOCKS(len
, pos
, blkbits
);
148 err
= ext4_map_blocks(NULL
, inode
, &map
, 0);
150 * 'err==len' means that all of the blocks have been preallocated,
151 * regardless of whether they have been initialized or not. To exclude
152 * unwritten extents, we need to check m_flags.
154 return err
== blklen
&& (map
.m_flags
& EXT4_MAP_MAPPED
);
157 static ssize_t
ext4_write_checks(struct kiocb
*iocb
, struct iov_iter
*from
)
159 struct inode
*inode
= file_inode(iocb
->ki_filp
);
162 ret
= generic_write_checks(iocb
, from
);
166 * If we have encountered a bitmap-format file, the size limit
167 * is smaller than s_maxbytes, which is for extent-mapped files.
169 if (!(ext4_test_inode_flag(inode
, EXT4_INODE_EXTENTS
))) {
170 struct ext4_sb_info
*sbi
= EXT4_SB(inode
->i_sb
);
172 if (iocb
->ki_pos
>= sbi
->s_bitmap_maxbytes
)
174 iov_iter_truncate(from
, sbi
->s_bitmap_maxbytes
- iocb
->ki_pos
);
176 return iov_iter_count(from
);
181 ext4_dax_write_iter(struct kiocb
*iocb
, struct iov_iter
*from
)
183 struct inode
*inode
= file_inode(iocb
->ki_filp
);
186 if (!inode_trylock(inode
)) {
187 if (iocb
->ki_flags
& IOCB_NOWAIT
)
191 ret
= ext4_write_checks(iocb
, from
);
194 ret
= file_remove_privs(iocb
->ki_filp
);
197 ret
= file_update_time(iocb
->ki_filp
);
201 ret
= dax_iomap_rw(iocb
, from
, &ext4_iomap_ops
);
205 ret
= generic_write_sync(iocb
, ret
);
211 ext4_file_write_iter(struct kiocb
*iocb
, struct iov_iter
*from
)
213 struct inode
*inode
= file_inode(iocb
->ki_filp
);
214 int o_direct
= iocb
->ki_flags
& IOCB_DIRECT
;
215 int unaligned_aio
= 0;
219 if (unlikely(ext4_forced_shutdown(EXT4_SB(inode
->i_sb
))))
224 return ext4_dax_write_iter(iocb
, from
);
227 if (!inode_trylock(inode
)) {
228 if (iocb
->ki_flags
& IOCB_NOWAIT
)
233 ret
= ext4_write_checks(iocb
, from
);
238 * Unaligned direct AIO must be serialized among each other as zeroing
239 * of partial blocks of two competing unaligned AIOs can result in data
242 if (o_direct
&& ext4_test_inode_flag(inode
, EXT4_INODE_EXTENTS
) &&
243 !is_sync_kiocb(iocb
) &&
244 ext4_unaligned_aio(inode
, from
, iocb
->ki_pos
)) {
246 ext4_unwritten_wait(inode
);
249 iocb
->private = &overwrite
;
250 /* Check whether we do a DIO overwrite or not */
251 if (o_direct
&& !unaligned_aio
) {
252 if (ext4_overwrite_io(inode
, iocb
->ki_pos
, iov_iter_count(from
))) {
253 if (ext4_should_dioread_nolock(inode
))
255 } else if (iocb
->ki_flags
& IOCB_NOWAIT
) {
261 ret
= __generic_file_write_iter(iocb
, from
);
265 ret
= generic_write_sync(iocb
, ret
);
275 static int ext4_dax_huge_fault(struct vm_fault
*vmf
,
276 enum page_entry_size pe_size
)
279 handle_t
*handle
= NULL
;
280 struct inode
*inode
= file_inode(vmf
->vma
->vm_file
);
281 struct super_block
*sb
= inode
->i_sb
;
282 bool write
= vmf
->flags
& FAULT_FLAG_WRITE
;
285 sb_start_pagefault(sb
);
286 file_update_time(vmf
->vma
->vm_file
);
287 down_read(&EXT4_I(inode
)->i_mmap_sem
);
288 handle
= ext4_journal_start_sb(sb
, EXT4_HT_WRITE_PAGE
,
289 EXT4_DATA_TRANS_BLOCKS(sb
));
291 down_read(&EXT4_I(inode
)->i_mmap_sem
);
294 result
= dax_iomap_fault(vmf
, pe_size
, &ext4_iomap_ops
);
296 result
= VM_FAULT_SIGBUS
;
299 ext4_journal_stop(handle
);
300 up_read(&EXT4_I(inode
)->i_mmap_sem
);
301 sb_end_pagefault(sb
);
303 up_read(&EXT4_I(inode
)->i_mmap_sem
);
309 static int ext4_dax_fault(struct vm_fault
*vmf
)
311 return ext4_dax_huge_fault(vmf
, PE_SIZE_PTE
);
315 * Handle write fault for VM_MIXEDMAP mappings. Similarly to ext4_dax_fault()
316 * handler we check for races agaist truncate. Note that since we cycle through
317 * i_mmap_sem, we are sure that also any hole punching that began before we
318 * were called is finished by now and so if it included part of the file we
319 * are working on, our pte will get unmapped and the check for pte_same() in
320 * wp_pfn_shared() fails. Thus fault gets retried and things work out as
323 static int ext4_dax_pfn_mkwrite(struct vm_fault
*vmf
)
325 struct inode
*inode
= file_inode(vmf
->vma
->vm_file
);
326 struct super_block
*sb
= inode
->i_sb
;
330 sb_start_pagefault(sb
);
331 file_update_time(vmf
->vma
->vm_file
);
332 down_read(&EXT4_I(inode
)->i_mmap_sem
);
333 size
= (i_size_read(inode
) + PAGE_SIZE
- 1) >> PAGE_SHIFT
;
334 if (vmf
->pgoff
>= size
)
335 ret
= VM_FAULT_SIGBUS
;
337 ret
= dax_pfn_mkwrite(vmf
);
338 up_read(&EXT4_I(inode
)->i_mmap_sem
);
339 sb_end_pagefault(sb
);
344 static const struct vm_operations_struct ext4_dax_vm_ops
= {
345 .fault
= ext4_dax_fault
,
346 .huge_fault
= ext4_dax_huge_fault
,
347 .page_mkwrite
= ext4_dax_fault
,
348 .pfn_mkwrite
= ext4_dax_pfn_mkwrite
,
351 #define ext4_dax_vm_ops ext4_file_vm_ops
354 static const struct vm_operations_struct ext4_file_vm_ops
= {
355 .fault
= ext4_filemap_fault
,
356 .map_pages
= filemap_map_pages
,
357 .page_mkwrite
= ext4_page_mkwrite
,
360 static int ext4_file_mmap(struct file
*file
, struct vm_area_struct
*vma
)
362 struct inode
*inode
= file
->f_mapping
->host
;
364 if (unlikely(ext4_forced_shutdown(EXT4_SB(inode
->i_sb
))))
368 if (IS_DAX(file_inode(file
))) {
369 vma
->vm_ops
= &ext4_dax_vm_ops
;
370 vma
->vm_flags
|= VM_MIXEDMAP
| VM_HUGEPAGE
;
372 vma
->vm_ops
= &ext4_file_vm_ops
;
377 static int ext4_file_open(struct inode
* inode
, struct file
* filp
)
379 struct super_block
*sb
= inode
->i_sb
;
380 struct ext4_sb_info
*sbi
= EXT4_SB(inode
->i_sb
);
381 struct vfsmount
*mnt
= filp
->f_path
.mnt
;
387 if (unlikely(ext4_forced_shutdown(EXT4_SB(inode
->i_sb
))))
390 if (unlikely(!(sbi
->s_mount_flags
& EXT4_MF_MNTDIR_SAMPLED
) &&
391 !(sb
->s_flags
& MS_RDONLY
))) {
392 sbi
->s_mount_flags
|= EXT4_MF_MNTDIR_SAMPLED
;
394 * Sample where the filesystem has been mounted and
395 * store it in the superblock for sysadmin convenience
396 * when trying to sort through large numbers of block
397 * devices or filesystem images.
399 memset(buf
, 0, sizeof(buf
));
401 path
.dentry
= mnt
->mnt_root
;
402 cp
= d_path(&path
, buf
, sizeof(buf
));
407 handle
= ext4_journal_start_sb(sb
, EXT4_HT_MISC
, 1);
409 return PTR_ERR(handle
);
410 BUFFER_TRACE(sbi
->s_sbh
, "get_write_access");
411 err
= ext4_journal_get_write_access(handle
, sbi
->s_sbh
);
413 ext4_journal_stop(handle
);
416 strlcpy(sbi
->s_es
->s_last_mounted
, cp
,
417 sizeof(sbi
->s_es
->s_last_mounted
));
418 ext4_handle_dirty_super(handle
, sb
);
419 ext4_journal_stop(handle
);
422 if (ext4_encrypted_inode(inode
)) {
423 ret
= fscrypt_get_encryption_info(inode
);
426 if (!fscrypt_has_encryption_key(inode
))
430 dir
= dget_parent(file_dentry(filp
));
431 if (ext4_encrypted_inode(d_inode(dir
)) &&
432 !fscrypt_has_permitted_context(d_inode(dir
), inode
)) {
433 ext4_warning(inode
->i_sb
,
434 "Inconsistent encryption contexts: %lu/%lu",
435 (unsigned long) d_inode(dir
)->i_ino
,
436 (unsigned long) inode
->i_ino
);
442 * Set up the jbd2_inode if we are opening the inode for
443 * writing and the journal is present
445 if (filp
->f_mode
& FMODE_WRITE
) {
446 ret
= ext4_inode_attach_jinode(inode
);
451 /* Set the flags to support nowait AIO */
452 filp
->f_mode
|= FMODE_AIO_NOWAIT
;
454 return dquot_file_open(inode
, filp
);
458 * Here we use ext4_map_blocks() to get a block mapping for a extent-based
459 * file rather than ext4_ext_walk_space() because we can introduce
460 * SEEK_DATA/SEEK_HOLE for block-mapped and extent-mapped file at the same
461 * function. When extent status tree has been fully implemented, it will
462 * track all extent status for a file and we can directly use it to
463 * retrieve the offset for SEEK_DATA/SEEK_HOLE.
467 * When we retrieve the offset for SEEK_DATA/SEEK_HOLE, we would need to
468 * lookup page cache to check whether or not there has some data between
469 * [startoff, endoff] because, if this range contains an unwritten extent,
470 * we determine this extent as a data or a hole according to whether the
471 * page cache has data or not.
473 static int ext4_find_unwritten_pgoff(struct inode
*inode
,
479 unsigned int blkbits
;
487 blkbits
= inode
->i_sb
->s_blocksize_bits
;
490 endoff
= (loff_t
)end_blk
<< blkbits
;
492 index
= startoff
>> PAGE_SHIFT
;
493 end
= (endoff
- 1) >> PAGE_SHIFT
;
495 pagevec_init(&pvec
, 0);
498 unsigned long nr_pages
;
500 num
= min_t(pgoff_t
, end
- index
, PAGEVEC_SIZE
- 1) + 1;
501 nr_pages
= pagevec_lookup(&pvec
, inode
->i_mapping
, index
,
506 for (i
= 0; i
< nr_pages
; i
++) {
507 struct page
*page
= pvec
.pages
[i
];
508 struct buffer_head
*bh
, *head
;
511 * If current offset is smaller than the page offset,
512 * there is a hole at this offset.
514 if (whence
== SEEK_HOLE
&& lastoff
< endoff
&&
515 lastoff
< page_offset(pvec
.pages
[i
])) {
521 if (page
->index
> end
)
526 if (unlikely(page
->mapping
!= inode
->i_mapping
)) {
531 if (!page_has_buffers(page
)) {
536 if (page_has_buffers(page
)) {
537 lastoff
= page_offset(page
);
538 bh
= head
= page_buffers(page
);
540 if (lastoff
+ bh
->b_size
<= startoff
)
542 if (buffer_uptodate(bh
) ||
543 buffer_unwritten(bh
)) {
544 if (whence
== SEEK_DATA
)
547 if (whence
== SEEK_HOLE
)
551 *offset
= max_t(loff_t
,
557 lastoff
+= bh
->b_size
;
558 bh
= bh
->b_this_page
;
559 } while (bh
!= head
);
562 lastoff
= page_offset(page
) + PAGE_SIZE
;
566 /* The no. of pages is less than our desired, we are done. */
570 index
= pvec
.pages
[i
- 1]->index
+ 1;
571 pagevec_release(&pvec
);
572 } while (index
<= end
);
574 if (whence
== SEEK_HOLE
&& lastoff
< endoff
) {
579 pagevec_release(&pvec
);
584 * ext4_seek_data() retrieves the offset for SEEK_DATA.
586 static loff_t
ext4_seek_data(struct file
*file
, loff_t offset
, loff_t maxsize
)
588 struct inode
*inode
= file
->f_mapping
->host
;
589 struct extent_status es
;
590 ext4_lblk_t start
, last
, end
;
591 loff_t dataoff
, isize
;
597 isize
= i_size_read(inode
);
598 if (offset
>= isize
) {
603 blkbits
= inode
->i_sb
->s_blocksize_bits
;
604 start
= offset
>> blkbits
;
606 end
= isize
>> blkbits
;
610 ret
= ext4_get_next_extent(inode
, last
, end
- last
+ 1, &es
);
612 /* No extent found -> no data */
621 dataoff
= (loff_t
)last
<< blkbits
;
622 if (!ext4_es_is_unwritten(&es
))
626 * If there is a unwritten extent at this offset,
627 * it will be as a data or a hole according to page
628 * cache that has data or not.
630 if (ext4_find_unwritten_pgoff(inode
, SEEK_DATA
,
631 es
.es_lblk
+ es
.es_len
, &dataoff
))
634 dataoff
= (loff_t
)last
<< blkbits
;
636 } while (last
<= end
);
643 return vfs_setpos(file
, dataoff
, maxsize
);
647 * ext4_seek_hole() retrieves the offset for SEEK_HOLE.
649 static loff_t
ext4_seek_hole(struct file
*file
, loff_t offset
, loff_t maxsize
)
651 struct inode
*inode
= file
->f_mapping
->host
;
652 struct extent_status es
;
653 ext4_lblk_t start
, last
, end
;
654 loff_t holeoff
, isize
;
660 isize
= i_size_read(inode
);
661 if (offset
>= isize
) {
666 blkbits
= inode
->i_sb
->s_blocksize_bits
;
667 start
= offset
>> blkbits
;
669 end
= isize
>> blkbits
;
673 ret
= ext4_get_next_extent(inode
, last
, end
- last
+ 1, &es
);
679 if (ret
== 0 || es
.es_lblk
> last
) {
681 holeoff
= (loff_t
)last
<< blkbits
;
685 * If there is a unwritten extent at this offset,
686 * it will be as a data or a hole according to page
687 * cache that has data or not.
689 if (ext4_es_is_unwritten(&es
) &&
690 ext4_find_unwritten_pgoff(inode
, SEEK_HOLE
,
691 last
+ es
.es_len
, &holeoff
))
695 holeoff
= (loff_t
)last
<< blkbits
;
697 } while (last
<= end
);
704 return vfs_setpos(file
, holeoff
, maxsize
);
708 * ext4_llseek() handles both block-mapped and extent-mapped maxbytes values
709 * by calling generic_file_llseek_size() with the appropriate maxbytes
712 loff_t
ext4_llseek(struct file
*file
, loff_t offset
, int whence
)
714 struct inode
*inode
= file
->f_mapping
->host
;
717 if (!(ext4_test_inode_flag(inode
, EXT4_INODE_EXTENTS
)))
718 maxbytes
= EXT4_SB(inode
->i_sb
)->s_bitmap_maxbytes
;
720 maxbytes
= inode
->i_sb
->s_maxbytes
;
726 return generic_file_llseek_size(file
, offset
, whence
,
727 maxbytes
, i_size_read(inode
));
729 return ext4_seek_data(file
, offset
, maxbytes
);
731 return ext4_seek_hole(file
, offset
, maxbytes
);
737 const struct file_operations ext4_file_operations
= {
738 .llseek
= ext4_llseek
,
739 .read_iter
= ext4_file_read_iter
,
740 .write_iter
= ext4_file_write_iter
,
741 .unlocked_ioctl
= ext4_ioctl
,
743 .compat_ioctl
= ext4_compat_ioctl
,
745 .mmap
= ext4_file_mmap
,
746 .open
= ext4_file_open
,
747 .release
= ext4_release_file
,
748 .fsync
= ext4_sync_file
,
749 .get_unmapped_area
= thp_get_unmapped_area
,
750 .splice_read
= generic_file_splice_read
,
751 .splice_write
= iter_file_splice_write
,
752 .fallocate
= ext4_fallocate
,
755 const struct inode_operations ext4_file_inode_operations
= {
756 .setattr
= ext4_setattr
,
757 .getattr
= ext4_file_getattr
,
758 .listxattr
= ext4_listxattr
,
759 .get_acl
= ext4_get_acl
,
760 .set_acl
= ext4_set_acl
,
761 .fiemap
= ext4_fiemap
,