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/aio.h>
27 #include <linux/quotaops.h>
28 #include <linux/pagevec.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, const struct iovec *iov,
78 unsigned long nr_segs, loff_t pos)
80 struct super_block *sb = inode->i_sb;
81 int blockmask = sb->s_blocksize - 1;
82 size_t count = iov_length(iov, nr_segs);
83 loff_t final_size = pos + count;
85 if (pos >= i_size_read(inode))
88 if ((pos & blockmask) || (final_size & blockmask))
95 ext4_file_write(struct kiocb *iocb, const struct iovec *iov,
96 unsigned long nr_segs, loff_t pos)
98 struct file *file = iocb->ki_filp;
99 struct inode *inode = file_inode(iocb->ki_filp);
100 struct mutex *aio_mutex = NULL;
101 struct blk_plug plug;
102 int o_direct = file->f_flags & O_DIRECT;
104 size_t length = iov_length(iov, nr_segs);
107 BUG_ON(iocb->ki_pos != pos);
110 * Unaligned direct AIO must be serialized; see comment above
111 * In the case of O_APPEND, assume that we must always serialize
114 ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS) &&
115 !is_sync_kiocb(iocb) &&
116 (file->f_flags & O_APPEND ||
117 ext4_unaligned_aio(inode, iov, nr_segs, pos))) {
118 aio_mutex = ext4_aio_mutex(inode);
119 mutex_lock(aio_mutex);
120 ext4_unwritten_wait(inode);
123 mutex_lock(&inode->i_mutex);
124 if (file->f_flags & O_APPEND)
125 iocb->ki_pos = pos = i_size_read(inode);
128 * If we have encountered a bitmap-format file, the size limit
129 * is smaller than s_maxbytes, which is for extent-mapped files.
131 if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) {
132 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
134 if ((pos > sbi->s_bitmap_maxbytes) ||
135 (pos == sbi->s_bitmap_maxbytes && length > 0)) {
136 mutex_unlock(&inode->i_mutex);
141 if (pos + length > sbi->s_bitmap_maxbytes) {
142 nr_segs = iov_shorten((struct iovec *)iov, nr_segs,
143 sbi->s_bitmap_maxbytes - pos);
148 blk_start_plug(&plug);
150 iocb->private = &overwrite;
152 /* check whether we do a DIO overwrite or not */
153 if (ext4_should_dioread_nolock(inode) && !aio_mutex &&
154 !file->f_mapping->nrpages && pos + length <= i_size_read(inode)) {
155 struct ext4_map_blocks map;
156 unsigned int blkbits = inode->i_blkbits;
159 map.m_lblk = pos >> blkbits;
160 map.m_len = (EXT4_BLOCK_ALIGN(pos + length, blkbits) >> blkbits)
164 err = ext4_map_blocks(NULL, inode, &map, 0);
166 * 'err==len' means that all of blocks has
167 * been preallocated no matter they are
168 * initialized or not. For excluding
169 * unwritten extents, we need to check
170 * m_flags. There are two conditions that
171 * indicate for initialized extents. 1) If we
172 * hit extent cache, EXT4_MAP_MAPPED flag is
173 * returned; 2) If we do a real lookup,
174 * non-flags are returned. So we should check
175 * these two conditions.
177 if (err == len && (map.m_flags & EXT4_MAP_MAPPED))
182 ret = __generic_file_aio_write(iocb, iov, nr_segs);
183 mutex_unlock(&inode->i_mutex);
188 err = generic_write_sync(file, iocb->ki_pos - ret, ret);
193 blk_finish_plug(&plug);
197 mutex_unlock(aio_mutex);
201 static const struct vm_operations_struct ext4_file_vm_ops = {
202 .fault = filemap_fault,
203 .map_pages = filemap_map_pages,
204 .page_mkwrite = ext4_page_mkwrite,
205 .remap_pages = generic_file_remap_pages,
208 static int ext4_file_mmap(struct file *file, struct vm_area_struct *vma)
210 struct address_space *mapping = file->f_mapping;
212 if (!mapping->a_ops->readpage)
215 vma->vm_ops = &ext4_file_vm_ops;
219 static int ext4_file_open(struct inode * inode, struct file * filp)
221 struct super_block *sb = inode->i_sb;
222 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
223 struct vfsmount *mnt = filp->f_path.mnt;
227 if (unlikely(!(sbi->s_mount_flags & EXT4_MF_MNTDIR_SAMPLED) &&
228 !(sb->s_flags & MS_RDONLY))) {
229 sbi->s_mount_flags |= EXT4_MF_MNTDIR_SAMPLED;
231 * Sample where the filesystem has been mounted and
232 * store it in the superblock for sysadmin convenience
233 * when trying to sort through large numbers of block
234 * devices or filesystem images.
236 memset(buf, 0, sizeof(buf));
238 path.dentry = mnt->mnt_root;
239 cp = d_path(&path, buf, sizeof(buf));
244 handle = ext4_journal_start_sb(sb, EXT4_HT_MISC, 1);
246 return PTR_ERR(handle);
247 BUFFER_TRACE(sbi->s_sbh, "get_write_access");
248 err = ext4_journal_get_write_access(handle, sbi->s_sbh);
250 ext4_journal_stop(handle);
253 strlcpy(sbi->s_es->s_last_mounted, cp,
254 sizeof(sbi->s_es->s_last_mounted));
255 ext4_handle_dirty_super(handle, sb);
256 ext4_journal_stop(handle);
260 * Set up the jbd2_inode if we are opening the inode for
261 * writing and the journal is present
263 if (filp->f_mode & FMODE_WRITE) {
264 int ret = ext4_inode_attach_jinode(inode);
268 return dquot_file_open(inode, filp);
272 * Here we use ext4_map_blocks() to get a block mapping for a extent-based
273 * file rather than ext4_ext_walk_space() because we can introduce
274 * SEEK_DATA/SEEK_HOLE for block-mapped and extent-mapped file at the same
275 * function. When extent status tree has been fully implemented, it will
276 * track all extent status for a file and we can directly use it to
277 * retrieve the offset for SEEK_DATA/SEEK_HOLE.
281 * When we retrieve the offset for SEEK_DATA/SEEK_HOLE, we would need to
282 * lookup page cache to check whether or not there has some data between
283 * [startoff, endoff] because, if this range contains an unwritten extent,
284 * we determine this extent as a data or a hole according to whether the
285 * page cache has data or not.
287 static int ext4_find_unwritten_pgoff(struct inode *inode,
289 struct ext4_map_blocks *map,
293 unsigned int blkbits;
301 blkbits = inode->i_sb->s_blocksize_bits;
304 endoff = (loff_t)(map->m_lblk + map->m_len) << blkbits;
306 index = startoff >> PAGE_CACHE_SHIFT;
307 end = endoff >> PAGE_CACHE_SHIFT;
309 pagevec_init(&pvec, 0);
312 unsigned long nr_pages;
314 num = min_t(pgoff_t, end - index, PAGEVEC_SIZE);
315 nr_pages = pagevec_lookup(&pvec, inode->i_mapping, index,
318 if (whence == SEEK_DATA)
321 BUG_ON(whence != SEEK_HOLE);
323 * If this is the first time to go into the loop and
324 * offset is not beyond the end offset, it will be a
325 * hole at this offset
327 if (lastoff == startoff || lastoff < endoff)
333 * If this is the first time to go into the loop and
334 * offset is smaller than the first page offset, it will be a
335 * hole at this offset.
337 if (lastoff == startoff && whence == SEEK_HOLE &&
338 lastoff < page_offset(pvec.pages[0])) {
343 for (i = 0; i < nr_pages; i++) {
344 struct page *page = pvec.pages[i];
345 struct buffer_head *bh, *head;
348 * If the current offset is not beyond the end of given
349 * range, it will be a hole.
351 if (lastoff < endoff && whence == SEEK_HOLE &&
360 if (unlikely(page->mapping != inode->i_mapping)) {
365 if (!page_has_buffers(page)) {
370 if (page_has_buffers(page)) {
371 lastoff = page_offset(page);
372 bh = head = page_buffers(page);
374 if (buffer_uptodate(bh) ||
375 buffer_unwritten(bh)) {
376 if (whence == SEEK_DATA)
379 if (whence == SEEK_HOLE)
383 *offset = max_t(loff_t,
388 lastoff += bh->b_size;
389 bh = bh->b_this_page;
390 } while (bh != head);
393 lastoff = page_offset(page) + PAGE_SIZE;
398 * The no. of pages is less than our desired, that would be a
401 if (nr_pages < num && whence == SEEK_HOLE) {
407 index = pvec.pages[i - 1]->index + 1;
408 pagevec_release(&pvec);
409 } while (index <= end);
412 pagevec_release(&pvec);
417 * ext4_seek_data() retrieves the offset for SEEK_DATA.
419 static loff_t ext4_seek_data(struct file *file, loff_t offset, loff_t maxsize)
421 struct inode *inode = file->f_mapping->host;
422 struct ext4_map_blocks map;
423 struct extent_status es;
424 ext4_lblk_t start, last, end;
425 loff_t dataoff, isize;
429 mutex_lock(&inode->i_mutex);
431 isize = i_size_read(inode);
432 if (offset >= isize) {
433 mutex_unlock(&inode->i_mutex);
437 blkbits = inode->i_sb->s_blocksize_bits;
438 start = offset >> blkbits;
440 end = isize >> blkbits;
445 map.m_len = end - last + 1;
446 ret = ext4_map_blocks(NULL, inode, &map, 0);
447 if (ret > 0 && !(map.m_flags & EXT4_MAP_UNWRITTEN)) {
449 dataoff = (loff_t)last << blkbits;
454 * If there is a delay extent at this offset,
455 * it will be as a data.
457 ext4_es_find_delayed_extent_range(inode, last, last, &es);
458 if (es.es_len != 0 && in_range(last, es.es_lblk, es.es_len)) {
460 dataoff = (loff_t)last << blkbits;
465 * If there is a unwritten extent at this offset,
466 * it will be as a data or a hole according to page
467 * cache that has data or not.
469 if (map.m_flags & EXT4_MAP_UNWRITTEN) {
471 unwritten = ext4_find_unwritten_pgoff(inode, SEEK_DATA,
478 dataoff = (loff_t)last << blkbits;
479 } while (last <= end);
481 mutex_unlock(&inode->i_mutex);
486 return vfs_setpos(file, dataoff, maxsize);
490 * ext4_seek_hole() retrieves the offset for SEEK_HOLE.
492 static loff_t ext4_seek_hole(struct file *file, loff_t offset, loff_t maxsize)
494 struct inode *inode = file->f_mapping->host;
495 struct ext4_map_blocks map;
496 struct extent_status es;
497 ext4_lblk_t start, last, end;
498 loff_t holeoff, isize;
502 mutex_lock(&inode->i_mutex);
504 isize = i_size_read(inode);
505 if (offset >= isize) {
506 mutex_unlock(&inode->i_mutex);
510 blkbits = inode->i_sb->s_blocksize_bits;
511 start = offset >> blkbits;
513 end = isize >> blkbits;
518 map.m_len = end - last + 1;
519 ret = ext4_map_blocks(NULL, inode, &map, 0);
520 if (ret > 0 && !(map.m_flags & EXT4_MAP_UNWRITTEN)) {
522 holeoff = (loff_t)last << blkbits;
527 * If there is a delay extent at this offset,
528 * we will skip this extent.
530 ext4_es_find_delayed_extent_range(inode, last, last, &es);
531 if (es.es_len != 0 && in_range(last, es.es_lblk, es.es_len)) {
532 last = es.es_lblk + es.es_len;
533 holeoff = (loff_t)last << blkbits;
538 * If there is a unwritten extent at this offset,
539 * it will be as a data or a hole according to page
540 * cache that has data or not.
542 if (map.m_flags & EXT4_MAP_UNWRITTEN) {
544 unwritten = ext4_find_unwritten_pgoff(inode, SEEK_HOLE,
548 holeoff = (loff_t)last << blkbits;
555 } while (last <= end);
557 mutex_unlock(&inode->i_mutex);
562 return vfs_setpos(file, holeoff, maxsize);
566 * ext4_llseek() handles both block-mapped and extent-mapped maxbytes values
567 * by calling generic_file_llseek_size() with the appropriate maxbytes
570 loff_t ext4_llseek(struct file *file, loff_t offset, int whence)
572 struct inode *inode = file->f_mapping->host;
575 if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
576 maxbytes = EXT4_SB(inode->i_sb)->s_bitmap_maxbytes;
578 maxbytes = inode->i_sb->s_maxbytes;
584 return generic_file_llseek_size(file, offset, whence,
585 maxbytes, i_size_read(inode));
587 return ext4_seek_data(file, offset, maxbytes);
589 return ext4_seek_hole(file, offset, maxbytes);
595 const struct file_operations ext4_file_operations = {
596 .llseek = ext4_llseek,
597 .read = do_sync_read,
598 .write = do_sync_write,
599 .aio_read = generic_file_aio_read,
600 .aio_write = ext4_file_write,
601 .unlocked_ioctl = ext4_ioctl,
603 .compat_ioctl = ext4_compat_ioctl,
605 .mmap = ext4_file_mmap,
606 .open = ext4_file_open,
607 .release = ext4_release_file,
608 .fsync = ext4_sync_file,
609 .splice_read = generic_file_splice_read,
610 .splice_write = generic_file_splice_write,
611 .fallocate = ext4_fallocate,
614 const struct inode_operations ext4_file_inode_operations = {
615 .setattr = ext4_setattr,
616 .getattr = ext4_getattr,
617 .setxattr = generic_setxattr,
618 .getxattr = generic_getxattr,
619 .listxattr = ext4_listxattr,
620 .removexattr = generic_removexattr,
621 .get_acl = ext4_get_acl,
622 .set_acl = ext4_set_acl,
623 .fiemap = ext4_fiemap,