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/aio.h>
26 #include <linux/quotaops.h>
27 #include <linux/pagevec.h>
29 #include "ext4_jbd2.h"
34 * Called when an inode is released. Note that this is different
35 * from ext4_file_open: open gets called at every open, but release
36 * gets called only when /all/ the files are closed.
38 static int ext4_release_file(struct inode *inode, struct file *filp)
40 if (ext4_test_inode_state(inode, EXT4_STATE_DA_ALLOC_CLOSE)) {
41 ext4_alloc_da_blocks(inode);
42 ext4_clear_inode_state(inode, EXT4_STATE_DA_ALLOC_CLOSE);
44 /* if we are the last writer on the inode, drop the block reservation */
45 if ((filp->f_mode & FMODE_WRITE) &&
46 (atomic_read(&inode->i_writecount) == 1) &&
47 !EXT4_I(inode)->i_reserved_data_blocks)
49 down_write(&EXT4_I(inode)->i_data_sem);
50 ext4_discard_preallocations(inode);
51 up_write(&EXT4_I(inode)->i_data_sem);
53 if (is_dx(inode) && filp->private_data)
54 ext4_htree_free_dir_info(filp->private_data);
59 static void ext4_unwritten_wait(struct inode *inode)
61 wait_queue_head_t *wq = ext4_ioend_wq(inode);
63 wait_event(*wq, (atomic_read(&EXT4_I(inode)->i_unwritten) == 0));
67 * This tests whether the IO in question is block-aligned or not.
68 * Ext4 utilizes unwritten extents when hole-filling during direct IO, and they
69 * are converted to written only after the IO is complete. Until they are
70 * mapped, these blocks appear as holes, so dio_zero_block() will assume that
71 * it needs to zero out portions of the start and/or end block. If 2 AIO
72 * threads are at work on the same unwritten block, they must be synchronized
73 * or one thread will zero the other's data, causing corruption.
76 ext4_unaligned_aio(struct inode *inode, struct iov_iter *from, loff_t pos)
78 struct super_block *sb = inode->i_sb;
79 int blockmask = sb->s_blocksize - 1;
81 if (pos >= i_size_read(inode))
84 if ((pos | iov_iter_alignment(from)) & blockmask)
91 ext4_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
93 struct file *file = iocb->ki_filp;
94 struct inode *inode = file_inode(iocb->ki_filp);
95 struct mutex *aio_mutex = NULL;
97 int o_direct = io_is_direct(file);
99 size_t length = iov_iter_count(from);
101 loff_t pos = iocb->ki_pos;
104 * Unaligned direct AIO must be serialized; see comment above
105 * In the case of O_APPEND, assume that we must always serialize
108 ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS) &&
109 !is_sync_kiocb(iocb) &&
110 (file->f_flags & O_APPEND ||
111 ext4_unaligned_aio(inode, from, pos))) {
112 aio_mutex = ext4_aio_mutex(inode);
113 mutex_lock(aio_mutex);
114 ext4_unwritten_wait(inode);
117 mutex_lock(&inode->i_mutex);
118 if (file->f_flags & O_APPEND)
119 iocb->ki_pos = pos = i_size_read(inode);
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 ((pos > sbi->s_bitmap_maxbytes) ||
129 (pos == sbi->s_bitmap_maxbytes && length > 0)) {
130 mutex_unlock(&inode->i_mutex);
135 if (pos + length > sbi->s_bitmap_maxbytes)
136 iov_iter_truncate(from, sbi->s_bitmap_maxbytes - pos);
139 iocb->private = &overwrite;
141 blk_start_plug(&plug);
144 /* check whether we do a DIO overwrite or not */
145 if (ext4_should_dioread_nolock(inode) && !aio_mutex &&
146 !file->f_mapping->nrpages && pos + length <= i_size_read(inode)) {
147 struct ext4_map_blocks map;
148 unsigned int blkbits = inode->i_blkbits;
151 map.m_lblk = pos >> blkbits;
152 map.m_len = (EXT4_BLOCK_ALIGN(pos + length, blkbits) >> blkbits)
156 err = ext4_map_blocks(NULL, inode, &map, 0);
158 * 'err==len' means that all of blocks has
159 * been preallocated no matter they are
160 * initialized or not. For excluding
161 * unwritten extents, we need to check
162 * m_flags. There are two conditions that
163 * indicate for initialized extents. 1) If we
164 * hit extent cache, EXT4_MAP_MAPPED flag is
165 * returned; 2) If we do a real lookup,
166 * non-flags are returned. So we should check
167 * these two conditions.
169 if (err == len && (map.m_flags & EXT4_MAP_MAPPED))
174 ret = __generic_file_write_iter(iocb, from);
175 mutex_unlock(&inode->i_mutex);
180 err = generic_write_sync(file, iocb->ki_pos - ret, ret);
185 blk_finish_plug(&plug);
189 mutex_unlock(aio_mutex);
194 static int ext4_dax_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
196 return dax_fault(vma, vmf, ext4_get_block);
197 /* Is this the right get_block? */
200 static int ext4_dax_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
202 return dax_mkwrite(vma, vmf, ext4_get_block);
205 static const struct vm_operations_struct ext4_dax_vm_ops = {
206 .fault = ext4_dax_fault,
207 .page_mkwrite = ext4_dax_mkwrite,
210 #define ext4_dax_vm_ops ext4_file_vm_ops
213 static const struct vm_operations_struct ext4_file_vm_ops = {
214 .fault = filemap_fault,
215 .map_pages = filemap_map_pages,
216 .page_mkwrite = ext4_page_mkwrite,
219 static int ext4_file_mmap(struct file *file, struct vm_area_struct *vma)
222 if (IS_DAX(file_inode(file))) {
223 vma->vm_ops = &ext4_dax_vm_ops;
224 vma->vm_flags |= VM_MIXEDMAP;
226 vma->vm_ops = &ext4_file_vm_ops;
231 static int ext4_file_open(struct inode * inode, struct file * filp)
233 struct super_block *sb = inode->i_sb;
234 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
235 struct vfsmount *mnt = filp->f_path.mnt;
239 if (unlikely(!(sbi->s_mount_flags & EXT4_MF_MNTDIR_SAMPLED) &&
240 !(sb->s_flags & MS_RDONLY))) {
241 sbi->s_mount_flags |= EXT4_MF_MNTDIR_SAMPLED;
243 * Sample where the filesystem has been mounted and
244 * store it in the superblock for sysadmin convenience
245 * when trying to sort through large numbers of block
246 * devices or filesystem images.
248 memset(buf, 0, sizeof(buf));
250 path.dentry = mnt->mnt_root;
251 cp = d_path(&path, buf, sizeof(buf));
256 handle = ext4_journal_start_sb(sb, EXT4_HT_MISC, 1);
258 return PTR_ERR(handle);
259 BUFFER_TRACE(sbi->s_sbh, "get_write_access");
260 err = ext4_journal_get_write_access(handle, sbi->s_sbh);
262 ext4_journal_stop(handle);
265 strlcpy(sbi->s_es->s_last_mounted, cp,
266 sizeof(sbi->s_es->s_last_mounted));
267 ext4_handle_dirty_super(handle, sb);
268 ext4_journal_stop(handle);
272 * Set up the jbd2_inode if we are opening the inode for
273 * writing and the journal is present
275 if (filp->f_mode & FMODE_WRITE) {
276 int ret = ext4_inode_attach_jinode(inode);
280 return dquot_file_open(inode, filp);
284 * Here we use ext4_map_blocks() to get a block mapping for a extent-based
285 * file rather than ext4_ext_walk_space() because we can introduce
286 * SEEK_DATA/SEEK_HOLE for block-mapped and extent-mapped file at the same
287 * function. When extent status tree has been fully implemented, it will
288 * track all extent status for a file and we can directly use it to
289 * retrieve the offset for SEEK_DATA/SEEK_HOLE.
293 * When we retrieve the offset for SEEK_DATA/SEEK_HOLE, we would need to
294 * lookup page cache to check whether or not there has some data between
295 * [startoff, endoff] because, if this range contains an unwritten extent,
296 * we determine this extent as a data or a hole according to whether the
297 * page cache has data or not.
299 static int ext4_find_unwritten_pgoff(struct inode *inode,
301 struct ext4_map_blocks *map,
305 unsigned int blkbits;
313 blkbits = inode->i_sb->s_blocksize_bits;
316 endoff = (loff_t)(map->m_lblk + map->m_len) << blkbits;
318 index = startoff >> PAGE_CACHE_SHIFT;
319 end = endoff >> PAGE_CACHE_SHIFT;
321 pagevec_init(&pvec, 0);
324 unsigned long nr_pages;
326 num = min_t(pgoff_t, end - index, PAGEVEC_SIZE);
327 nr_pages = pagevec_lookup(&pvec, inode->i_mapping, index,
330 if (whence == SEEK_DATA)
333 BUG_ON(whence != SEEK_HOLE);
335 * If this is the first time to go into the loop and
336 * offset is not beyond the end offset, it will be a
337 * hole at this offset
339 if (lastoff == startoff || lastoff < endoff)
345 * If this is the first time to go into the loop and
346 * offset is smaller than the first page offset, it will be a
347 * hole at this offset.
349 if (lastoff == startoff && whence == SEEK_HOLE &&
350 lastoff < page_offset(pvec.pages[0])) {
355 for (i = 0; i < nr_pages; i++) {
356 struct page *page = pvec.pages[i];
357 struct buffer_head *bh, *head;
360 * If the current offset is not beyond the end of given
361 * range, it will be a hole.
363 if (lastoff < endoff && whence == SEEK_HOLE &&
372 if (unlikely(page->mapping != inode->i_mapping)) {
377 if (!page_has_buffers(page)) {
382 if (page_has_buffers(page)) {
383 lastoff = page_offset(page);
384 bh = head = page_buffers(page);
386 if (buffer_uptodate(bh) ||
387 buffer_unwritten(bh)) {
388 if (whence == SEEK_DATA)
391 if (whence == SEEK_HOLE)
395 *offset = max_t(loff_t,
400 lastoff += bh->b_size;
401 bh = bh->b_this_page;
402 } while (bh != head);
405 lastoff = page_offset(page) + PAGE_SIZE;
410 * The no. of pages is less than our desired, that would be a
413 if (nr_pages < num && whence == SEEK_HOLE) {
419 index = pvec.pages[i - 1]->index + 1;
420 pagevec_release(&pvec);
421 } while (index <= end);
424 pagevec_release(&pvec);
429 * ext4_seek_data() retrieves the offset for SEEK_DATA.
431 static loff_t ext4_seek_data(struct file *file, loff_t offset, loff_t maxsize)
433 struct inode *inode = file->f_mapping->host;
434 struct ext4_map_blocks map;
435 struct extent_status es;
436 ext4_lblk_t start, last, end;
437 loff_t dataoff, isize;
441 mutex_lock(&inode->i_mutex);
443 isize = i_size_read(inode);
444 if (offset >= isize) {
445 mutex_unlock(&inode->i_mutex);
449 blkbits = inode->i_sb->s_blocksize_bits;
450 start = offset >> blkbits;
452 end = isize >> blkbits;
457 map.m_len = end - last + 1;
458 ret = ext4_map_blocks(NULL, inode, &map, 0);
459 if (ret > 0 && !(map.m_flags & EXT4_MAP_UNWRITTEN)) {
461 dataoff = (loff_t)last << blkbits;
466 * If there is a delay extent at this offset,
467 * it will be as a data.
469 ext4_es_find_delayed_extent_range(inode, last, last, &es);
470 if (es.es_len != 0 && in_range(last, es.es_lblk, es.es_len)) {
472 dataoff = (loff_t)last << blkbits;
477 * If there is a unwritten extent at this offset,
478 * it will be as a data or a hole according to page
479 * cache that has data or not.
481 if (map.m_flags & EXT4_MAP_UNWRITTEN) {
483 unwritten = ext4_find_unwritten_pgoff(inode, SEEK_DATA,
490 dataoff = (loff_t)last << blkbits;
491 } while (last <= end);
493 mutex_unlock(&inode->i_mutex);
498 return vfs_setpos(file, dataoff, maxsize);
502 * ext4_seek_hole() retrieves the offset for SEEK_HOLE.
504 static loff_t ext4_seek_hole(struct file *file, loff_t offset, loff_t maxsize)
506 struct inode *inode = file->f_mapping->host;
507 struct ext4_map_blocks map;
508 struct extent_status es;
509 ext4_lblk_t start, last, end;
510 loff_t holeoff, isize;
514 mutex_lock(&inode->i_mutex);
516 isize = i_size_read(inode);
517 if (offset >= isize) {
518 mutex_unlock(&inode->i_mutex);
522 blkbits = inode->i_sb->s_blocksize_bits;
523 start = offset >> blkbits;
525 end = isize >> blkbits;
530 map.m_len = end - last + 1;
531 ret = ext4_map_blocks(NULL, inode, &map, 0);
532 if (ret > 0 && !(map.m_flags & EXT4_MAP_UNWRITTEN)) {
534 holeoff = (loff_t)last << blkbits;
539 * If there is a delay extent at this offset,
540 * we will skip this extent.
542 ext4_es_find_delayed_extent_range(inode, last, last, &es);
543 if (es.es_len != 0 && in_range(last, es.es_lblk, es.es_len)) {
544 last = es.es_lblk + es.es_len;
545 holeoff = (loff_t)last << blkbits;
550 * If there is a unwritten extent at this offset,
551 * it will be as a data or a hole according to page
552 * cache that has data or not.
554 if (map.m_flags & EXT4_MAP_UNWRITTEN) {
556 unwritten = ext4_find_unwritten_pgoff(inode, SEEK_HOLE,
560 holeoff = (loff_t)last << blkbits;
567 } while (last <= end);
569 mutex_unlock(&inode->i_mutex);
574 return vfs_setpos(file, holeoff, maxsize);
578 * ext4_llseek() handles both block-mapped and extent-mapped maxbytes values
579 * by calling generic_file_llseek_size() with the appropriate maxbytes
582 loff_t ext4_llseek(struct file *file, loff_t offset, int whence)
584 struct inode *inode = file->f_mapping->host;
587 if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
588 maxbytes = EXT4_SB(inode->i_sb)->s_bitmap_maxbytes;
590 maxbytes = inode->i_sb->s_maxbytes;
596 return generic_file_llseek_size(file, offset, whence,
597 maxbytes, i_size_read(inode));
599 return ext4_seek_data(file, offset, maxbytes);
601 return ext4_seek_hole(file, offset, maxbytes);
607 const struct file_operations ext4_file_operations = {
608 .llseek = ext4_llseek,
609 .read = new_sync_read,
610 .write = new_sync_write,
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 = new_sync_read,
630 .write = new_sync_write,
631 .read_iter = generic_file_read_iter,
632 .write_iter = ext4_file_write_iter,
633 .unlocked_ioctl = ext4_ioctl,
635 .compat_ioctl = ext4_compat_ioctl,
637 .mmap = ext4_file_mmap,
638 .open = ext4_file_open,
639 .release = ext4_release_file,
640 .fsync = ext4_sync_file,
641 /* Splice not yet supported with DAX */
642 .fallocate = ext4_fallocate,
646 const struct inode_operations ext4_file_inode_operations = {
647 .setattr = ext4_setattr,
648 .getattr = ext4_getattr,
649 .setxattr = generic_setxattr,
650 .getxattr = generic_getxattr,
651 .listxattr = ext4_listxattr,
652 .removexattr = generic_removexattr,
653 .get_acl = ext4_get_acl,
654 .set_acl = ext4_set_acl,
655 .fiemap = ext4_fiemap,