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1/*
2 * linux/fs/ext4/file.c
3 *
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)
8 *
9 * from
10 *
11 * linux/fs/minix/file.c
12 *
13 * Copyright (C) 1991, 1992 Linus Torvalds
14 *
15 * ext4 fs regular file handling primitives
16 *
17 * 64-bit file support on 64-bit platforms by Jakub Jelinek
18 * (jj@sunsite.ms.mff.cuni.cz)
19 */
20
21#include <linux/time.h>
22#include <linux/fs.h>
23#include <linux/jbd2.h>
24#include <linux/mount.h>
25#include <linux/path.h>
26#include <linux/quotaops.h>
27#include "ext4.h"
28#include "ext4_jbd2.h"
29#include "xattr.h"
30#include "acl.h"
31
32/*
33 * Called when an inode is released. Note that this is different
34 * from ext4_file_open: open gets called at every open, but release
35 * gets called only when /all/ the files are closed.
36 */
37static int ext4_release_file(struct inode *inode, struct file *filp)
38{
39 if (ext4_test_inode_state(inode, EXT4_STATE_DA_ALLOC_CLOSE)) {
40 ext4_alloc_da_blocks(inode);
41 ext4_clear_inode_state(inode, EXT4_STATE_DA_ALLOC_CLOSE);
42 }
43 /* if we are the last writer on the inode, drop the block reservation */
44 if ((filp->f_mode & FMODE_WRITE) &&
45 (atomic_read(&inode->i_writecount) == 1) &&
46 !EXT4_I(inode)->i_reserved_data_blocks)
47 {
48 down_write(&EXT4_I(inode)->i_data_sem);
49 ext4_discard_preallocations(inode);
50 up_write(&EXT4_I(inode)->i_data_sem);
51 }
52 if (is_dx(inode) && filp->private_data)
53 ext4_htree_free_dir_info(filp->private_data);
54
55 return 0;
56}
57
58static void ext4_aiodio_wait(struct inode *inode)
59{
60 wait_queue_head_t *wq = ext4_ioend_wq(inode);
61
62 wait_event(*wq, (atomic_read(&EXT4_I(inode)->i_aiodio_unwritten) == 0));
63}
64
65/*
66 * This tests whether the IO in question is block-aligned or not.
67 * Ext4 utilizes unwritten extents when hole-filling during direct IO, and they
68 * are converted to written only after the IO is complete. Until they are
69 * mapped, these blocks appear as holes, so dio_zero_block() will assume that
70 * it needs to zero out portions of the start and/or end block. If 2 AIO
71 * threads are at work on the same unwritten block, they must be synchronized
72 * or one thread will zero the other's data, causing corruption.
73 */
74static int
75ext4_unaligned_aio(struct inode *inode, const struct iovec *iov,
76 unsigned long nr_segs, loff_t pos)
77{
78 struct super_block *sb = inode->i_sb;
79 int blockmask = sb->s_blocksize - 1;
80 size_t count = iov_length(iov, nr_segs);
81 loff_t final_size = pos + count;
82
83 if (pos >= inode->i_size)
84 return 0;
85
86 if ((pos & blockmask) || (final_size & blockmask))
87 return 1;
88
89 return 0;
90}
91
92static ssize_t
93ext4_file_write(struct kiocb *iocb, const struct iovec *iov,
94 unsigned long nr_segs, loff_t pos)
95{
96 struct inode *inode = iocb->ki_filp->f_path.dentry->d_inode;
97 int unaligned_aio = 0;
98 int ret;
99
100 /*
101 * If we have encountered a bitmap-format file, the size limit
102 * is smaller than s_maxbytes, which is for extent-mapped files.
103 */
104
105 if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) {
106 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
107 size_t length = iov_length(iov, nr_segs);
108
109 if ((pos > sbi->s_bitmap_maxbytes ||
110 (pos == sbi->s_bitmap_maxbytes && length > 0)))
111 return -EFBIG;
112
113 if (pos + length > sbi->s_bitmap_maxbytes) {
114 nr_segs = iov_shorten((struct iovec *)iov, nr_segs,
115 sbi->s_bitmap_maxbytes - pos);
116 }
117 } else if (unlikely((iocb->ki_filp->f_flags & O_DIRECT) &&
118 !is_sync_kiocb(iocb))) {
119 unaligned_aio = ext4_unaligned_aio(inode, iov, nr_segs, pos);
120 }
121
122 /* Unaligned direct AIO must be serialized; see comment above */
123 if (unaligned_aio) {
124 static unsigned long unaligned_warn_time;
125
126 /* Warn about this once per day */
127 if (printk_timed_ratelimit(&unaligned_warn_time, 60*60*24*HZ))
128 ext4_msg(inode->i_sb, KERN_WARNING,
129 "Unaligned AIO/DIO on inode %ld by %s; "
130 "performance will be poor.",
131 inode->i_ino, current->comm);
132 mutex_lock(ext4_aio_mutex(inode));
133 ext4_aiodio_wait(inode);
134 }
135
136 ret = generic_file_aio_write(iocb, iov, nr_segs, pos);
137
138 if (unaligned_aio)
139 mutex_unlock(ext4_aio_mutex(inode));
140
141 return ret;
142}
143
144static const struct vm_operations_struct ext4_file_vm_ops = {
145 .fault = filemap_fault,
146 .page_mkwrite = ext4_page_mkwrite,
147};
148
149static int ext4_file_mmap(struct file *file, struct vm_area_struct *vma)
150{
151 struct address_space *mapping = file->f_mapping;
152
153 if (!mapping->a_ops->readpage)
154 return -ENOEXEC;
155 file_accessed(file);
156 vma->vm_ops = &ext4_file_vm_ops;
157 vma->vm_flags |= VM_CAN_NONLINEAR;
158 return 0;
159}
160
161static int ext4_file_open(struct inode * inode, struct file * filp)
162{
163 struct super_block *sb = inode->i_sb;
164 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
165 struct ext4_inode_info *ei = EXT4_I(inode);
166 struct vfsmount *mnt = filp->f_path.mnt;
167 struct path path;
168 char buf[64], *cp;
169
170 if (unlikely(!(sbi->s_mount_flags & EXT4_MF_MNTDIR_SAMPLED) &&
171 !(sb->s_flags & MS_RDONLY))) {
172 sbi->s_mount_flags |= EXT4_MF_MNTDIR_SAMPLED;
173 /*
174 * Sample where the filesystem has been mounted and
175 * store it in the superblock for sysadmin convenience
176 * when trying to sort through large numbers of block
177 * devices or filesystem images.
178 */
179 memset(buf, 0, sizeof(buf));
180 path.mnt = mnt;
181 path.dentry = mnt->mnt_root;
182 cp = d_path(&path, buf, sizeof(buf));
183 if (!IS_ERR(cp)) {
184 memcpy(sbi->s_es->s_last_mounted, cp,
185 sizeof(sbi->s_es->s_last_mounted));
186 ext4_mark_super_dirty(sb);
187 }
188 }
189 /*
190 * Set up the jbd2_inode if we are opening the inode for
191 * writing and the journal is present
192 */
193 if (sbi->s_journal && !ei->jinode && (filp->f_mode & FMODE_WRITE)) {
194 struct jbd2_inode *jinode = jbd2_alloc_inode(GFP_KERNEL);
195
196 spin_lock(&inode->i_lock);
197 if (!ei->jinode) {
198 if (!jinode) {
199 spin_unlock(&inode->i_lock);
200 return -ENOMEM;
201 }
202 ei->jinode = jinode;
203 jbd2_journal_init_jbd_inode(ei->jinode, inode);
204 jinode = NULL;
205 }
206 spin_unlock(&inode->i_lock);
207 if (unlikely(jinode != NULL))
208 jbd2_free_inode(jinode);
209 }
210 return dquot_file_open(inode, filp);
211}
212
213/*
214 * ext4_llseek() copied from generic_file_llseek() to handle both
215 * block-mapped and extent-mapped maxbytes values. This should
216 * otherwise be identical with generic_file_llseek().
217 */
218loff_t ext4_llseek(struct file *file, loff_t offset, int origin)
219{
220 struct inode *inode = file->f_mapping->host;
221 loff_t maxbytes;
222
223 if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
224 maxbytes = EXT4_SB(inode->i_sb)->s_bitmap_maxbytes;
225 else
226 maxbytes = inode->i_sb->s_maxbytes;
227 mutex_lock(&inode->i_mutex);
228 switch (origin) {
229 case SEEK_END:
230 offset += inode->i_size;
231 break;
232 case SEEK_CUR:
233 if (offset == 0) {
234 mutex_unlock(&inode->i_mutex);
235 return file->f_pos;
236 }
237 offset += file->f_pos;
238 break;
239 case SEEK_DATA:
240 /*
241 * In the generic case the entire file is data, so as long as
242 * offset isn't at the end of the file then the offset is data.
243 */
244 if (offset >= inode->i_size) {
245 mutex_unlock(&inode->i_mutex);
246 return -ENXIO;
247 }
248 break;
249 case SEEK_HOLE:
250 /*
251 * There is a virtual hole at the end of the file, so as long as
252 * offset isn't i_size or larger, return i_size.
253 */
254 if (offset >= inode->i_size) {
255 mutex_unlock(&inode->i_mutex);
256 return -ENXIO;
257 }
258 offset = inode->i_size;
259 break;
260 }
261
262 if (offset < 0 || offset > maxbytes) {
263 mutex_unlock(&inode->i_mutex);
264 return -EINVAL;
265 }
266
267 if (offset != file->f_pos) {
268 file->f_pos = offset;
269 file->f_version = 0;
270 }
271 mutex_unlock(&inode->i_mutex);
272
273 return offset;
274}
275
276const struct file_operations ext4_file_operations = {
277 .llseek = ext4_llseek,
278 .read = do_sync_read,
279 .write = do_sync_write,
280 .aio_read = generic_file_aio_read,
281 .aio_write = ext4_file_write,
282 .unlocked_ioctl = ext4_ioctl,
283#ifdef CONFIG_COMPAT
284 .compat_ioctl = ext4_compat_ioctl,
285#endif
286 .mmap = ext4_file_mmap,
287 .open = ext4_file_open,
288 .release = ext4_release_file,
289 .fsync = ext4_sync_file,
290 .splice_read = generic_file_splice_read,
291 .splice_write = generic_file_splice_write,
292 .fallocate = ext4_fallocate,
293};
294
295const struct inode_operations ext4_file_inode_operations = {
296 .setattr = ext4_setattr,
297 .getattr = ext4_getattr,
298#ifdef CONFIG_EXT4_FS_XATTR
299 .setxattr = generic_setxattr,
300 .getxattr = generic_getxattr,
301 .listxattr = ext4_listxattr,
302 .removexattr = generic_removexattr,
303#endif
304 .get_acl = ext4_get_acl,
305 .fiemap = ext4_fiemap,
306};
307
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * linux/fs/ext4/file.c
4 *
5 * Copyright (C) 1992, 1993, 1994, 1995
6 * Remy Card (card@masi.ibp.fr)
7 * Laboratoire MASI - Institut Blaise Pascal
8 * Universite Pierre et Marie Curie (Paris VI)
9 *
10 * from
11 *
12 * linux/fs/minix/file.c
13 *
14 * Copyright (C) 1991, 1992 Linus Torvalds
15 *
16 * ext4 fs regular file handling primitives
17 *
18 * 64-bit file support on 64-bit platforms by Jakub Jelinek
19 * (jj@sunsite.ms.mff.cuni.cz)
20 */
21
22#include <linux/time.h>
23#include <linux/fs.h>
24#include <linux/iomap.h>
25#include <linux/mount.h>
26#include <linux/path.h>
27#include <linux/dax.h>
28#include <linux/quotaops.h>
29#include <linux/pagevec.h>
30#include <linux/uio.h>
31#include <linux/mman.h>
32#include <linux/backing-dev.h>
33#include "ext4.h"
34#include "ext4_jbd2.h"
35#include "xattr.h"
36#include "acl.h"
37#include "truncate.h"
38
39static bool ext4_dio_supported(struct inode *inode)
40{
41 if (IS_ENABLED(CONFIG_FS_ENCRYPTION) && IS_ENCRYPTED(inode))
42 return false;
43 if (fsverity_active(inode))
44 return false;
45 if (ext4_should_journal_data(inode))
46 return false;
47 if (ext4_has_inline_data(inode))
48 return false;
49 return true;
50}
51
52static ssize_t ext4_dio_read_iter(struct kiocb *iocb, struct iov_iter *to)
53{
54 ssize_t ret;
55 struct inode *inode = file_inode(iocb->ki_filp);
56
57 if (iocb->ki_flags & IOCB_NOWAIT) {
58 if (!inode_trylock_shared(inode))
59 return -EAGAIN;
60 } else {
61 inode_lock_shared(inode);
62 }
63
64 if (!ext4_dio_supported(inode)) {
65 inode_unlock_shared(inode);
66 /*
67 * Fallback to buffered I/O if the operation being performed on
68 * the inode is not supported by direct I/O. The IOCB_DIRECT
69 * flag needs to be cleared here in order to ensure that the
70 * direct I/O path within generic_file_read_iter() is not
71 * taken.
72 */
73 iocb->ki_flags &= ~IOCB_DIRECT;
74 return generic_file_read_iter(iocb, to);
75 }
76
77 ret = iomap_dio_rw(iocb, to, &ext4_iomap_ops, NULL, 0);
78 inode_unlock_shared(inode);
79
80 file_accessed(iocb->ki_filp);
81 return ret;
82}
83
84#ifdef CONFIG_FS_DAX
85static ssize_t ext4_dax_read_iter(struct kiocb *iocb, struct iov_iter *to)
86{
87 struct inode *inode = file_inode(iocb->ki_filp);
88 ssize_t ret;
89
90 if (iocb->ki_flags & IOCB_NOWAIT) {
91 if (!inode_trylock_shared(inode))
92 return -EAGAIN;
93 } else {
94 inode_lock_shared(inode);
95 }
96 /*
97 * Recheck under inode lock - at this point we are sure it cannot
98 * change anymore
99 */
100 if (!IS_DAX(inode)) {
101 inode_unlock_shared(inode);
102 /* Fallback to buffered IO in case we cannot support DAX */
103 return generic_file_read_iter(iocb, to);
104 }
105 ret = dax_iomap_rw(iocb, to, &ext4_iomap_ops);
106 inode_unlock_shared(inode);
107
108 file_accessed(iocb->ki_filp);
109 return ret;
110}
111#endif
112
113static ssize_t ext4_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
114{
115 struct inode *inode = file_inode(iocb->ki_filp);
116
117 if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb))))
118 return -EIO;
119
120 if (!iov_iter_count(to))
121 return 0; /* skip atime */
122
123#ifdef CONFIG_FS_DAX
124 if (IS_DAX(inode))
125 return ext4_dax_read_iter(iocb, to);
126#endif
127 if (iocb->ki_flags & IOCB_DIRECT)
128 return ext4_dio_read_iter(iocb, to);
129
130 return generic_file_read_iter(iocb, to);
131}
132
133/*
134 * Called when an inode is released. Note that this is different
135 * from ext4_file_open: open gets called at every open, but release
136 * gets called only when /all/ the files are closed.
137 */
138static int ext4_release_file(struct inode *inode, struct file *filp)
139{
140 if (ext4_test_inode_state(inode, EXT4_STATE_DA_ALLOC_CLOSE)) {
141 ext4_alloc_da_blocks(inode);
142 ext4_clear_inode_state(inode, EXT4_STATE_DA_ALLOC_CLOSE);
143 }
144 /* if we are the last writer on the inode, drop the block reservation */
145 if ((filp->f_mode & FMODE_WRITE) &&
146 (atomic_read(&inode->i_writecount) == 1) &&
147 !EXT4_I(inode)->i_reserved_data_blocks) {
148 down_write(&EXT4_I(inode)->i_data_sem);
149 ext4_discard_preallocations(inode, 0);
150 up_write(&EXT4_I(inode)->i_data_sem);
151 }
152 if (is_dx(inode) && filp->private_data)
153 ext4_htree_free_dir_info(filp->private_data);
154
155 return 0;
156}
157
158/*
159 * This tests whether the IO in question is block-aligned or not.
160 * Ext4 utilizes unwritten extents when hole-filling during direct IO, and they
161 * are converted to written only after the IO is complete. Until they are
162 * mapped, these blocks appear as holes, so dio_zero_block() will assume that
163 * it needs to zero out portions of the start and/or end block. If 2 AIO
164 * threads are at work on the same unwritten block, they must be synchronized
165 * or one thread will zero the other's data, causing corruption.
166 */
167static bool
168ext4_unaligned_io(struct inode *inode, struct iov_iter *from, loff_t pos)
169{
170 struct super_block *sb = inode->i_sb;
171 unsigned long blockmask = sb->s_blocksize - 1;
172
173 if ((pos | iov_iter_alignment(from)) & blockmask)
174 return true;
175
176 return false;
177}
178
179static bool
180ext4_extending_io(struct inode *inode, loff_t offset, size_t len)
181{
182 if (offset + len > i_size_read(inode) ||
183 offset + len > EXT4_I(inode)->i_disksize)
184 return true;
185 return false;
186}
187
188/* Is IO overwriting allocated and initialized blocks? */
189static bool ext4_overwrite_io(struct inode *inode, loff_t pos, loff_t len)
190{
191 struct ext4_map_blocks map;
192 unsigned int blkbits = inode->i_blkbits;
193 int err, blklen;
194
195 if (pos + len > i_size_read(inode))
196 return false;
197
198 map.m_lblk = pos >> blkbits;
199 map.m_len = EXT4_MAX_BLOCKS(len, pos, blkbits);
200 blklen = map.m_len;
201
202 err = ext4_map_blocks(NULL, inode, &map, 0);
203 /*
204 * 'err==len' means that all of the blocks have been preallocated,
205 * regardless of whether they have been initialized or not. To exclude
206 * unwritten extents, we need to check m_flags.
207 */
208 return err == blklen && (map.m_flags & EXT4_MAP_MAPPED);
209}
210
211static ssize_t ext4_generic_write_checks(struct kiocb *iocb,
212 struct iov_iter *from)
213{
214 struct inode *inode = file_inode(iocb->ki_filp);
215 ssize_t ret;
216
217 if (unlikely(IS_IMMUTABLE(inode)))
218 return -EPERM;
219
220 ret = generic_write_checks(iocb, from);
221 if (ret <= 0)
222 return ret;
223
224 /*
225 * If we have encountered a bitmap-format file, the size limit
226 * is smaller than s_maxbytes, which is for extent-mapped files.
227 */
228 if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) {
229 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
230
231 if (iocb->ki_pos >= sbi->s_bitmap_maxbytes)
232 return -EFBIG;
233 iov_iter_truncate(from, sbi->s_bitmap_maxbytes - iocb->ki_pos);
234 }
235
236 return iov_iter_count(from);
237}
238
239static ssize_t ext4_write_checks(struct kiocb *iocb, struct iov_iter *from)
240{
241 ssize_t ret, count;
242
243 count = ext4_generic_write_checks(iocb, from);
244 if (count <= 0)
245 return count;
246
247 ret = file_modified(iocb->ki_filp);
248 if (ret)
249 return ret;
250 return count;
251}
252
253static ssize_t ext4_buffered_write_iter(struct kiocb *iocb,
254 struct iov_iter *from)
255{
256 ssize_t ret;
257 struct inode *inode = file_inode(iocb->ki_filp);
258
259 if (iocb->ki_flags & IOCB_NOWAIT)
260 return -EOPNOTSUPP;
261
262 ext4_fc_start_update(inode);
263 inode_lock(inode);
264 ret = ext4_write_checks(iocb, from);
265 if (ret <= 0)
266 goto out;
267
268 current->backing_dev_info = inode_to_bdi(inode);
269 ret = generic_perform_write(iocb->ki_filp, from, iocb->ki_pos);
270 current->backing_dev_info = NULL;
271
272out:
273 inode_unlock(inode);
274 ext4_fc_stop_update(inode);
275 if (likely(ret > 0)) {
276 iocb->ki_pos += ret;
277 ret = generic_write_sync(iocb, ret);
278 }
279
280 return ret;
281}
282
283static ssize_t ext4_handle_inode_extension(struct inode *inode, loff_t offset,
284 ssize_t written, size_t count)
285{
286 handle_t *handle;
287 bool truncate = false;
288 u8 blkbits = inode->i_blkbits;
289 ext4_lblk_t written_blk, end_blk;
290 int ret;
291
292 /*
293 * Note that EXT4_I(inode)->i_disksize can get extended up to
294 * inode->i_size while the I/O was running due to writeback of delalloc
295 * blocks. But, the code in ext4_iomap_alloc() is careful to use
296 * zeroed/unwritten extents if this is possible; thus we won't leave
297 * uninitialized blocks in a file even if we didn't succeed in writing
298 * as much as we intended.
299 */
300 WARN_ON_ONCE(i_size_read(inode) < EXT4_I(inode)->i_disksize);
301 if (offset + count <= EXT4_I(inode)->i_disksize) {
302 /*
303 * We need to ensure that the inode is removed from the orphan
304 * list if it has been added prematurely, due to writeback of
305 * delalloc blocks.
306 */
307 if (!list_empty(&EXT4_I(inode)->i_orphan) && inode->i_nlink) {
308 handle = ext4_journal_start(inode, EXT4_HT_INODE, 2);
309
310 if (IS_ERR(handle)) {
311 ext4_orphan_del(NULL, inode);
312 return PTR_ERR(handle);
313 }
314
315 ext4_orphan_del(handle, inode);
316 ext4_journal_stop(handle);
317 }
318
319 return written;
320 }
321
322 if (written < 0)
323 goto truncate;
324
325 handle = ext4_journal_start(inode, EXT4_HT_INODE, 2);
326 if (IS_ERR(handle)) {
327 written = PTR_ERR(handle);
328 goto truncate;
329 }
330
331 if (ext4_update_inode_size(inode, offset + written)) {
332 ret = ext4_mark_inode_dirty(handle, inode);
333 if (unlikely(ret)) {
334 written = ret;
335 ext4_journal_stop(handle);
336 goto truncate;
337 }
338 }
339
340 /*
341 * We may need to truncate allocated but not written blocks beyond EOF.
342 */
343 written_blk = ALIGN(offset + written, 1 << blkbits);
344 end_blk = ALIGN(offset + count, 1 << blkbits);
345 if (written_blk < end_blk && ext4_can_truncate(inode))
346 truncate = true;
347
348 /*
349 * Remove the inode from the orphan list if it has been extended and
350 * everything went OK.
351 */
352 if (!truncate && inode->i_nlink)
353 ext4_orphan_del(handle, inode);
354 ext4_journal_stop(handle);
355
356 if (truncate) {
357truncate:
358 ext4_truncate_failed_write(inode);
359 /*
360 * If the truncate operation failed early, then the inode may
361 * still be on the orphan list. In that case, we need to try
362 * remove the inode from the in-memory linked list.
363 */
364 if (inode->i_nlink)
365 ext4_orphan_del(NULL, inode);
366 }
367
368 return written;
369}
370
371static int ext4_dio_write_end_io(struct kiocb *iocb, ssize_t size,
372 int error, unsigned int flags)
373{
374 loff_t pos = iocb->ki_pos;
375 struct inode *inode = file_inode(iocb->ki_filp);
376
377 if (error)
378 return error;
379
380 if (size && flags & IOMAP_DIO_UNWRITTEN) {
381 error = ext4_convert_unwritten_extents(NULL, inode, pos, size);
382 if (error < 0)
383 return error;
384 }
385 /*
386 * If we are extending the file, we have to update i_size here before
387 * page cache gets invalidated in iomap_dio_rw(). Otherwise racing
388 * buffered reads could zero out too much from page cache pages. Update
389 * of on-disk size will happen later in ext4_dio_write_iter() where
390 * we have enough information to also perform orphan list handling etc.
391 * Note that we perform all extending writes synchronously under
392 * i_rwsem held exclusively so i_size update is safe here in that case.
393 * If the write was not extending, we cannot see pos > i_size here
394 * because operations reducing i_size like truncate wait for all
395 * outstanding DIO before updating i_size.
396 */
397 pos += size;
398 if (pos > i_size_read(inode))
399 i_size_write(inode, pos);
400
401 return 0;
402}
403
404static const struct iomap_dio_ops ext4_dio_write_ops = {
405 .end_io = ext4_dio_write_end_io,
406};
407
408/*
409 * The intention here is to start with shared lock acquired then see if any
410 * condition requires an exclusive inode lock. If yes, then we restart the
411 * whole operation by releasing the shared lock and acquiring exclusive lock.
412 *
413 * - For unaligned_io we never take shared lock as it may cause data corruption
414 * when two unaligned IO tries to modify the same block e.g. while zeroing.
415 *
416 * - For extending writes case we don't take the shared lock, since it requires
417 * updating inode i_disksize and/or orphan handling with exclusive lock.
418 *
419 * - shared locking will only be true mostly with overwrites. Otherwise we will
420 * switch to exclusive i_rwsem lock.
421 */
422static ssize_t ext4_dio_write_checks(struct kiocb *iocb, struct iov_iter *from,
423 bool *ilock_shared, bool *extend)
424{
425 struct file *file = iocb->ki_filp;
426 struct inode *inode = file_inode(file);
427 loff_t offset;
428 size_t count;
429 ssize_t ret;
430
431restart:
432 ret = ext4_generic_write_checks(iocb, from);
433 if (ret <= 0)
434 goto out;
435
436 offset = iocb->ki_pos;
437 count = ret;
438 if (ext4_extending_io(inode, offset, count))
439 *extend = true;
440 /*
441 * Determine whether the IO operation will overwrite allocated
442 * and initialized blocks.
443 * We need exclusive i_rwsem for changing security info
444 * in file_modified().
445 */
446 if (*ilock_shared && (!IS_NOSEC(inode) || *extend ||
447 !ext4_overwrite_io(inode, offset, count))) {
448 if (iocb->ki_flags & IOCB_NOWAIT) {
449 ret = -EAGAIN;
450 goto out;
451 }
452 inode_unlock_shared(inode);
453 *ilock_shared = false;
454 inode_lock(inode);
455 goto restart;
456 }
457
458 ret = file_modified(file);
459 if (ret < 0)
460 goto out;
461
462 return count;
463out:
464 if (*ilock_shared)
465 inode_unlock_shared(inode);
466 else
467 inode_unlock(inode);
468 return ret;
469}
470
471static ssize_t ext4_dio_write_iter(struct kiocb *iocb, struct iov_iter *from)
472{
473 ssize_t ret;
474 handle_t *handle;
475 struct inode *inode = file_inode(iocb->ki_filp);
476 loff_t offset = iocb->ki_pos;
477 size_t count = iov_iter_count(from);
478 const struct iomap_ops *iomap_ops = &ext4_iomap_ops;
479 bool extend = false, unaligned_io = false;
480 bool ilock_shared = true;
481
482 /*
483 * We initially start with shared inode lock unless it is
484 * unaligned IO which needs exclusive lock anyways.
485 */
486 if (ext4_unaligned_io(inode, from, offset)) {
487 unaligned_io = true;
488 ilock_shared = false;
489 }
490 /*
491 * Quick check here without any i_rwsem lock to see if it is extending
492 * IO. A more reliable check is done in ext4_dio_write_checks() with
493 * proper locking in place.
494 */
495 if (offset + count > i_size_read(inode))
496 ilock_shared = false;
497
498 if (iocb->ki_flags & IOCB_NOWAIT) {
499 if (ilock_shared) {
500 if (!inode_trylock_shared(inode))
501 return -EAGAIN;
502 } else {
503 if (!inode_trylock(inode))
504 return -EAGAIN;
505 }
506 } else {
507 if (ilock_shared)
508 inode_lock_shared(inode);
509 else
510 inode_lock(inode);
511 }
512
513 /* Fallback to buffered I/O if the inode does not support direct I/O. */
514 if (!ext4_dio_supported(inode)) {
515 if (ilock_shared)
516 inode_unlock_shared(inode);
517 else
518 inode_unlock(inode);
519 return ext4_buffered_write_iter(iocb, from);
520 }
521
522 ret = ext4_dio_write_checks(iocb, from, &ilock_shared, &extend);
523 if (ret <= 0)
524 return ret;
525
526 /* if we're going to block and IOCB_NOWAIT is set, return -EAGAIN */
527 if ((iocb->ki_flags & IOCB_NOWAIT) && (unaligned_io || extend)) {
528 ret = -EAGAIN;
529 goto out;
530 }
531
532 offset = iocb->ki_pos;
533 count = ret;
534
535 /*
536 * Unaligned direct IO must be serialized among each other as zeroing
537 * of partial blocks of two competing unaligned IOs can result in data
538 * corruption.
539 *
540 * So we make sure we don't allow any unaligned IO in flight.
541 * For IOs where we need not wait (like unaligned non-AIO DIO),
542 * below inode_dio_wait() may anyway become a no-op, since we start
543 * with exclusive lock.
544 */
545 if (unaligned_io)
546 inode_dio_wait(inode);
547
548 if (extend) {
549 handle = ext4_journal_start(inode, EXT4_HT_INODE, 2);
550 if (IS_ERR(handle)) {
551 ret = PTR_ERR(handle);
552 goto out;
553 }
554
555 ext4_fc_start_update(inode);
556 ret = ext4_orphan_add(handle, inode);
557 ext4_fc_stop_update(inode);
558 if (ret) {
559 ext4_journal_stop(handle);
560 goto out;
561 }
562
563 ext4_journal_stop(handle);
564 }
565
566 if (ilock_shared)
567 iomap_ops = &ext4_iomap_overwrite_ops;
568 ret = iomap_dio_rw(iocb, from, iomap_ops, &ext4_dio_write_ops,
569 (unaligned_io || extend) ? IOMAP_DIO_FORCE_WAIT : 0);
570 if (ret == -ENOTBLK)
571 ret = 0;
572
573 if (extend)
574 ret = ext4_handle_inode_extension(inode, offset, ret, count);
575
576out:
577 if (ilock_shared)
578 inode_unlock_shared(inode);
579 else
580 inode_unlock(inode);
581
582 if (ret >= 0 && iov_iter_count(from)) {
583 ssize_t err;
584 loff_t endbyte;
585
586 offset = iocb->ki_pos;
587 err = ext4_buffered_write_iter(iocb, from);
588 if (err < 0)
589 return err;
590
591 /*
592 * We need to ensure that the pages within the page cache for
593 * the range covered by this I/O are written to disk and
594 * invalidated. This is in attempt to preserve the expected
595 * direct I/O semantics in the case we fallback to buffered I/O
596 * to complete off the I/O request.
597 */
598 ret += err;
599 endbyte = offset + err - 1;
600 err = filemap_write_and_wait_range(iocb->ki_filp->f_mapping,
601 offset, endbyte);
602 if (!err)
603 invalidate_mapping_pages(iocb->ki_filp->f_mapping,
604 offset >> PAGE_SHIFT,
605 endbyte >> PAGE_SHIFT);
606 }
607
608 return ret;
609}
610
611#ifdef CONFIG_FS_DAX
612static ssize_t
613ext4_dax_write_iter(struct kiocb *iocb, struct iov_iter *from)
614{
615 ssize_t ret;
616 size_t count;
617 loff_t offset;
618 handle_t *handle;
619 bool extend = false;
620 struct inode *inode = file_inode(iocb->ki_filp);
621
622 if (iocb->ki_flags & IOCB_NOWAIT) {
623 if (!inode_trylock(inode))
624 return -EAGAIN;
625 } else {
626 inode_lock(inode);
627 }
628
629 ret = ext4_write_checks(iocb, from);
630 if (ret <= 0)
631 goto out;
632
633 offset = iocb->ki_pos;
634 count = iov_iter_count(from);
635
636 if (offset + count > EXT4_I(inode)->i_disksize) {
637 handle = ext4_journal_start(inode, EXT4_HT_INODE, 2);
638 if (IS_ERR(handle)) {
639 ret = PTR_ERR(handle);
640 goto out;
641 }
642
643 ret = ext4_orphan_add(handle, inode);
644 if (ret) {
645 ext4_journal_stop(handle);
646 goto out;
647 }
648
649 extend = true;
650 ext4_journal_stop(handle);
651 }
652
653 ret = dax_iomap_rw(iocb, from, &ext4_iomap_ops);
654
655 if (extend)
656 ret = ext4_handle_inode_extension(inode, offset, ret, count);
657out:
658 inode_unlock(inode);
659 if (ret > 0)
660 ret = generic_write_sync(iocb, ret);
661 return ret;
662}
663#endif
664
665static ssize_t
666ext4_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
667{
668 struct inode *inode = file_inode(iocb->ki_filp);
669
670 if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb))))
671 return -EIO;
672
673#ifdef CONFIG_FS_DAX
674 if (IS_DAX(inode))
675 return ext4_dax_write_iter(iocb, from);
676#endif
677 if (iocb->ki_flags & IOCB_DIRECT)
678 return ext4_dio_write_iter(iocb, from);
679 else
680 return ext4_buffered_write_iter(iocb, from);
681}
682
683#ifdef CONFIG_FS_DAX
684static vm_fault_t ext4_dax_huge_fault(struct vm_fault *vmf,
685 enum page_entry_size pe_size)
686{
687 int error = 0;
688 vm_fault_t result;
689 int retries = 0;
690 handle_t *handle = NULL;
691 struct inode *inode = file_inode(vmf->vma->vm_file);
692 struct super_block *sb = inode->i_sb;
693
694 /*
695 * We have to distinguish real writes from writes which will result in a
696 * COW page; COW writes should *not* poke the journal (the file will not
697 * be changed). Doing so would cause unintended failures when mounted
698 * read-only.
699 *
700 * We check for VM_SHARED rather than vmf->cow_page since the latter is
701 * unset for pe_size != PE_SIZE_PTE (i.e. only in do_cow_fault); for
702 * other sizes, dax_iomap_fault will handle splitting / fallback so that
703 * we eventually come back with a COW page.
704 */
705 bool write = (vmf->flags & FAULT_FLAG_WRITE) &&
706 (vmf->vma->vm_flags & VM_SHARED);
707 pfn_t pfn;
708
709 if (write) {
710 sb_start_pagefault(sb);
711 file_update_time(vmf->vma->vm_file);
712 down_read(&EXT4_I(inode)->i_mmap_sem);
713retry:
714 handle = ext4_journal_start_sb(sb, EXT4_HT_WRITE_PAGE,
715 EXT4_DATA_TRANS_BLOCKS(sb));
716 if (IS_ERR(handle)) {
717 up_read(&EXT4_I(inode)->i_mmap_sem);
718 sb_end_pagefault(sb);
719 return VM_FAULT_SIGBUS;
720 }
721 } else {
722 down_read(&EXT4_I(inode)->i_mmap_sem);
723 }
724 result = dax_iomap_fault(vmf, pe_size, &pfn, &error, &ext4_iomap_ops);
725 if (write) {
726 ext4_journal_stop(handle);
727
728 if ((result & VM_FAULT_ERROR) && error == -ENOSPC &&
729 ext4_should_retry_alloc(sb, &retries))
730 goto retry;
731 /* Handling synchronous page fault? */
732 if (result & VM_FAULT_NEEDDSYNC)
733 result = dax_finish_sync_fault(vmf, pe_size, pfn);
734 up_read(&EXT4_I(inode)->i_mmap_sem);
735 sb_end_pagefault(sb);
736 } else {
737 up_read(&EXT4_I(inode)->i_mmap_sem);
738 }
739
740 return result;
741}
742
743static vm_fault_t ext4_dax_fault(struct vm_fault *vmf)
744{
745 return ext4_dax_huge_fault(vmf, PE_SIZE_PTE);
746}
747
748static const struct vm_operations_struct ext4_dax_vm_ops = {
749 .fault = ext4_dax_fault,
750 .huge_fault = ext4_dax_huge_fault,
751 .page_mkwrite = ext4_dax_fault,
752 .pfn_mkwrite = ext4_dax_fault,
753};
754#else
755#define ext4_dax_vm_ops ext4_file_vm_ops
756#endif
757
758static const struct vm_operations_struct ext4_file_vm_ops = {
759 .fault = ext4_filemap_fault,
760 .map_pages = filemap_map_pages,
761 .page_mkwrite = ext4_page_mkwrite,
762};
763
764static int ext4_file_mmap(struct file *file, struct vm_area_struct *vma)
765{
766 struct inode *inode = file->f_mapping->host;
767 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
768 struct dax_device *dax_dev = sbi->s_daxdev;
769
770 if (unlikely(ext4_forced_shutdown(sbi)))
771 return -EIO;
772
773 /*
774 * We don't support synchronous mappings for non-DAX files and
775 * for DAX files if underneath dax_device is not synchronous.
776 */
777 if (!daxdev_mapping_supported(vma, dax_dev))
778 return -EOPNOTSUPP;
779
780 file_accessed(file);
781 if (IS_DAX(file_inode(file))) {
782 vma->vm_ops = &ext4_dax_vm_ops;
783 vma->vm_flags |= VM_HUGEPAGE;
784 } else {
785 vma->vm_ops = &ext4_file_vm_ops;
786 }
787 return 0;
788}
789
790static int ext4_sample_last_mounted(struct super_block *sb,
791 struct vfsmount *mnt)
792{
793 struct ext4_sb_info *sbi = EXT4_SB(sb);
794 struct path path;
795 char buf[64], *cp;
796 handle_t *handle;
797 int err;
798
799 if (likely(ext4_test_mount_flag(sb, EXT4_MF_MNTDIR_SAMPLED)))
800 return 0;
801
802 if (sb_rdonly(sb) || !sb_start_intwrite_trylock(sb))
803 return 0;
804
805 ext4_set_mount_flag(sb, EXT4_MF_MNTDIR_SAMPLED);
806 /*
807 * Sample where the filesystem has been mounted and
808 * store it in the superblock for sysadmin convenience
809 * when trying to sort through large numbers of block
810 * devices or filesystem images.
811 */
812 memset(buf, 0, sizeof(buf));
813 path.mnt = mnt;
814 path.dentry = mnt->mnt_root;
815 cp = d_path(&path, buf, sizeof(buf));
816 err = 0;
817 if (IS_ERR(cp))
818 goto out;
819
820 handle = ext4_journal_start_sb(sb, EXT4_HT_MISC, 1);
821 err = PTR_ERR(handle);
822 if (IS_ERR(handle))
823 goto out;
824 BUFFER_TRACE(sbi->s_sbh, "get_write_access");
825 err = ext4_journal_get_write_access(handle, sbi->s_sbh);
826 if (err)
827 goto out_journal;
828 lock_buffer(sbi->s_sbh);
829 strncpy(sbi->s_es->s_last_mounted, cp,
830 sizeof(sbi->s_es->s_last_mounted));
831 ext4_superblock_csum_set(sb);
832 unlock_buffer(sbi->s_sbh);
833 ext4_handle_dirty_metadata(handle, NULL, sbi->s_sbh);
834out_journal:
835 ext4_journal_stop(handle);
836out:
837 sb_end_intwrite(sb);
838 return err;
839}
840
841static int ext4_file_open(struct inode *inode, struct file *filp)
842{
843 int ret;
844
845 if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb))))
846 return -EIO;
847
848 ret = ext4_sample_last_mounted(inode->i_sb, filp->f_path.mnt);
849 if (ret)
850 return ret;
851
852 ret = fscrypt_file_open(inode, filp);
853 if (ret)
854 return ret;
855
856 ret = fsverity_file_open(inode, filp);
857 if (ret)
858 return ret;
859
860 /*
861 * Set up the jbd2_inode if we are opening the inode for
862 * writing and the journal is present
863 */
864 if (filp->f_mode & FMODE_WRITE) {
865 ret = ext4_inode_attach_jinode(inode);
866 if (ret < 0)
867 return ret;
868 }
869
870 filp->f_mode |= FMODE_NOWAIT | FMODE_BUF_RASYNC;
871 return dquot_file_open(inode, filp);
872}
873
874/*
875 * ext4_llseek() handles both block-mapped and extent-mapped maxbytes values
876 * by calling generic_file_llseek_size() with the appropriate maxbytes
877 * value for each.
878 */
879loff_t ext4_llseek(struct file *file, loff_t offset, int whence)
880{
881 struct inode *inode = file->f_mapping->host;
882 loff_t maxbytes;
883
884 if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
885 maxbytes = EXT4_SB(inode->i_sb)->s_bitmap_maxbytes;
886 else
887 maxbytes = inode->i_sb->s_maxbytes;
888
889 switch (whence) {
890 default:
891 return generic_file_llseek_size(file, offset, whence,
892 maxbytes, i_size_read(inode));
893 case SEEK_HOLE:
894 inode_lock_shared(inode);
895 offset = iomap_seek_hole(inode, offset,
896 &ext4_iomap_report_ops);
897 inode_unlock_shared(inode);
898 break;
899 case SEEK_DATA:
900 inode_lock_shared(inode);
901 offset = iomap_seek_data(inode, offset,
902 &ext4_iomap_report_ops);
903 inode_unlock_shared(inode);
904 break;
905 }
906
907 if (offset < 0)
908 return offset;
909 return vfs_setpos(file, offset, maxbytes);
910}
911
912const struct file_operations ext4_file_operations = {
913 .llseek = ext4_llseek,
914 .read_iter = ext4_file_read_iter,
915 .write_iter = ext4_file_write_iter,
916 .iopoll = iomap_dio_iopoll,
917 .unlocked_ioctl = ext4_ioctl,
918#ifdef CONFIG_COMPAT
919 .compat_ioctl = ext4_compat_ioctl,
920#endif
921 .mmap = ext4_file_mmap,
922 .mmap_supported_flags = MAP_SYNC,
923 .open = ext4_file_open,
924 .release = ext4_release_file,
925 .fsync = ext4_sync_file,
926 .get_unmapped_area = thp_get_unmapped_area,
927 .splice_read = generic_file_splice_read,
928 .splice_write = iter_file_splice_write,
929 .fallocate = ext4_fallocate,
930};
931
932const struct inode_operations ext4_file_inode_operations = {
933 .setattr = ext4_setattr,
934 .getattr = ext4_file_getattr,
935 .listxattr = ext4_listxattr,
936 .get_acl = ext4_get_acl,
937 .set_acl = ext4_set_acl,
938 .fiemap = ext4_fiemap,
939 .fileattr_get = ext4_fileattr_get,
940 .fileattr_set = ext4_fileattr_set,
941};
942