1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * linux/fs/ext2/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 * ext2 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/pagemap.h>
24 #include <linux/dax.h>
25 #include <linux/filelock.h>
26 #include <linux/quotaops.h>
27 #include <linux/iomap.h>
28 #include <linux/uio.h>
29 #include <linux/buffer_head.h>
30 #include "ext2.h"
31 #include "xattr.h"
32 #include "acl.h"
33 #include "trace.h"
34
35 #ifdef CONFIG_FS_DAX
ext2_dax_read_iter(struct kiocb * iocb,struct iov_iter * to)36 static ssize_t ext2_dax_read_iter(struct kiocb *iocb, struct iov_iter *to)
37 {
38 struct inode *inode = iocb->ki_filp->f_mapping->host;
39 ssize_t ret;
40
41 if (!iov_iter_count(to))
42 return 0; /* skip atime */
43
44 inode_lock_shared(inode);
45 ret = dax_iomap_rw(iocb, to, &ext2_iomap_ops);
46 inode_unlock_shared(inode);
47
48 file_accessed(iocb->ki_filp);
49 return ret;
50 }
51
ext2_dax_write_iter(struct kiocb * iocb,struct iov_iter * from)52 static ssize_t ext2_dax_write_iter(struct kiocb *iocb, struct iov_iter *from)
53 {
54 struct file *file = iocb->ki_filp;
55 struct inode *inode = file->f_mapping->host;
56 ssize_t ret;
57
58 inode_lock(inode);
59 ret = generic_write_checks(iocb, from);
60 if (ret <= 0)
61 goto out_unlock;
62 ret = file_remove_privs(file);
63 if (ret)
64 goto out_unlock;
65 ret = file_update_time(file);
66 if (ret)
67 goto out_unlock;
68
69 ret = dax_iomap_rw(iocb, from, &ext2_iomap_ops);
70 if (ret > 0 && iocb->ki_pos > i_size_read(inode)) {
71 i_size_write(inode, iocb->ki_pos);
72 mark_inode_dirty(inode);
73 }
74
75 out_unlock:
76 inode_unlock(inode);
77 if (ret > 0)
78 ret = generic_write_sync(iocb, ret);
79 return ret;
80 }
81
82 /*
83 * The lock ordering for ext2 DAX fault paths is:
84 *
85 * mmap_lock (MM)
86 * sb_start_pagefault (vfs, freeze)
87 * address_space->invalidate_lock
88 * address_space->i_mmap_rwsem or page_lock (mutually exclusive in DAX)
89 * ext2_inode_info->truncate_mutex
90 *
91 * The default page_lock and i_size verification done by non-DAX fault paths
92 * is sufficient because ext2 doesn't support hole punching.
93 */
ext2_dax_fault(struct vm_fault * vmf)94 static vm_fault_t ext2_dax_fault(struct vm_fault *vmf)
95 {
96 struct inode *inode = file_inode(vmf->vma->vm_file);
97 vm_fault_t ret;
98 bool write = (vmf->flags & FAULT_FLAG_WRITE) &&
99 (vmf->vma->vm_flags & VM_SHARED);
100
101 if (write) {
102 sb_start_pagefault(inode->i_sb);
103 file_update_time(vmf->vma->vm_file);
104 }
105 filemap_invalidate_lock_shared(inode->i_mapping);
106
107 ret = dax_iomap_fault(vmf, 0, NULL, NULL, &ext2_iomap_ops);
108
109 filemap_invalidate_unlock_shared(inode->i_mapping);
110 if (write)
111 sb_end_pagefault(inode->i_sb);
112 return ret;
113 }
114
115 static const struct vm_operations_struct ext2_dax_vm_ops = {
116 .fault = ext2_dax_fault,
117 /*
118 * .huge_fault is not supported for DAX because allocation in ext2
119 * cannot be reliably aligned to huge page sizes and so pmd faults
120 * will always fail and fail back to regular faults.
121 */
122 .page_mkwrite = ext2_dax_fault,
123 .pfn_mkwrite = ext2_dax_fault,
124 };
125
ext2_file_mmap_prepare(struct vm_area_desc * desc)126 static int ext2_file_mmap_prepare(struct vm_area_desc *desc)
127 {
128 struct file *file = desc->file;
129
130 if (!IS_DAX(file_inode(file)))
131 return generic_file_mmap_prepare(desc);
132
133 file_accessed(file);
134 desc->vm_ops = &ext2_dax_vm_ops;
135 return 0;
136 }
137 #else
138 #define ext2_file_mmap_prepare generic_file_mmap_prepare
139 #endif
140
141 /*
142 * Called when filp is released. This happens when all file descriptors
143 * for a single struct file are closed. Note that different open() calls
144 * for the same file yield different struct file structures.
145 */
ext2_release_file(struct inode * inode,struct file * filp)146 static int ext2_release_file (struct inode * inode, struct file * filp)
147 {
148 if (filp->f_mode & FMODE_WRITE) {
149 mutex_lock(&EXT2_I(inode)->truncate_mutex);
150 ext2_discard_reservation(inode);
151 mutex_unlock(&EXT2_I(inode)->truncate_mutex);
152 }
153 return 0;
154 }
155
ext2_fsync(struct file * file,loff_t start,loff_t end,int datasync)156 int ext2_fsync(struct file *file, loff_t start, loff_t end, int datasync)
157 {
158 int ret;
159 struct super_block *sb = file->f_mapping->host->i_sb;
160
161 ret = generic_buffers_fsync(file, start, end, datasync);
162 if (ret == -EIO)
163 /* We don't really know where the IO error happened... */
164 ext2_error(sb, __func__,
165 "detected IO error when writing metadata buffers");
166 return ret;
167 }
168
ext2_dio_read_iter(struct kiocb * iocb,struct iov_iter * to)169 static ssize_t ext2_dio_read_iter(struct kiocb *iocb, struct iov_iter *to)
170 {
171 struct file *file = iocb->ki_filp;
172 struct inode *inode = file->f_mapping->host;
173 ssize_t ret;
174
175 trace_ext2_dio_read_begin(iocb, to, 0);
176 inode_lock_shared(inode);
177 ret = iomap_dio_rw(iocb, to, &ext2_iomap_ops, NULL, 0, NULL, 0);
178 inode_unlock_shared(inode);
179 trace_ext2_dio_read_end(iocb, to, ret);
180
181 return ret;
182 }
183
ext2_dio_write_end_io(struct kiocb * iocb,ssize_t size,int error,unsigned int flags)184 static int ext2_dio_write_end_io(struct kiocb *iocb, ssize_t size,
185 int error, unsigned int flags)
186 {
187 loff_t pos = iocb->ki_pos;
188 struct inode *inode = file_inode(iocb->ki_filp);
189
190 if (error)
191 goto out;
192
193 /*
194 * If we are extending the file, we have to update i_size here before
195 * page cache gets invalidated in iomap_dio_rw(). This prevents racing
196 * buffered reads from zeroing out too much from page cache pages.
197 * Note that all extending writes always happens synchronously with
198 * inode lock held by ext2_dio_write_iter(). So it is safe to update
199 * inode size here for extending file writes.
200 */
201 pos += size;
202 if (pos > i_size_read(inode)) {
203 i_size_write(inode, pos);
204 mark_inode_dirty(inode);
205 }
206 out:
207 trace_ext2_dio_write_endio(iocb, size, error);
208 return error;
209 }
210
211 static const struct iomap_dio_ops ext2_dio_write_ops = {
212 .end_io = ext2_dio_write_end_io,
213 };
214
ext2_dio_write_iter(struct kiocb * iocb,struct iov_iter * from)215 static ssize_t ext2_dio_write_iter(struct kiocb *iocb, struct iov_iter *from)
216 {
217 struct file *file = iocb->ki_filp;
218 struct inode *inode = file->f_mapping->host;
219 ssize_t ret;
220 unsigned int flags = 0;
221 unsigned long blocksize = inode->i_sb->s_blocksize;
222 loff_t offset = iocb->ki_pos;
223 loff_t count = iov_iter_count(from);
224 ssize_t status = 0;
225
226 trace_ext2_dio_write_begin(iocb, from, 0);
227 inode_lock(inode);
228 ret = generic_write_checks(iocb, from);
229 if (ret <= 0)
230 goto out_unlock;
231
232 ret = kiocb_modified(iocb);
233 if (ret)
234 goto out_unlock;
235
236 /* use IOMAP_DIO_FORCE_WAIT for unaligned or extending writes */
237 if (iocb->ki_pos + iov_iter_count(from) > i_size_read(inode) ||
238 (!IS_ALIGNED(iocb->ki_pos | iov_iter_alignment(from), blocksize)))
239 flags |= IOMAP_DIO_FORCE_WAIT;
240
241 ret = iomap_dio_rw(iocb, from, &ext2_iomap_ops, &ext2_dio_write_ops,
242 flags, NULL, 0);
243
244 /* ENOTBLK is magic return value for fallback to buffered-io */
245 if (ret == -ENOTBLK)
246 ret = 0;
247
248 if (ret < 0 && ret != -EIOCBQUEUED)
249 ext2_write_failed(inode->i_mapping, offset + count);
250
251 /* handle case for partial write and for fallback to buffered write */
252 if (ret >= 0 && iov_iter_count(from)) {
253 loff_t pos, endbyte;
254 int ret2;
255
256 iocb->ki_flags &= ~IOCB_DIRECT;
257 pos = iocb->ki_pos;
258 status = generic_perform_write(iocb, from);
259 if (unlikely(status < 0)) {
260 ret = status;
261 goto out_unlock;
262 }
263
264 ret += status;
265 endbyte = pos + status - 1;
266 ret2 = filemap_write_and_wait_range(inode->i_mapping, pos,
267 endbyte);
268 if (!ret2)
269 invalidate_mapping_pages(inode->i_mapping,
270 pos >> PAGE_SHIFT,
271 endbyte >> PAGE_SHIFT);
272 if (ret > 0)
273 generic_write_sync(iocb, ret);
274 }
275
276 out_unlock:
277 inode_unlock(inode);
278 if (status)
279 trace_ext2_dio_write_buff_end(iocb, from, status);
280 trace_ext2_dio_write_end(iocb, from, ret);
281 return ret;
282 }
283
ext2_file_read_iter(struct kiocb * iocb,struct iov_iter * to)284 static ssize_t ext2_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
285 {
286 #ifdef CONFIG_FS_DAX
287 if (IS_DAX(iocb->ki_filp->f_mapping->host))
288 return ext2_dax_read_iter(iocb, to);
289 #endif
290 if (iocb->ki_flags & IOCB_DIRECT)
291 return ext2_dio_read_iter(iocb, to);
292
293 return generic_file_read_iter(iocb, to);
294 }
295
ext2_file_write_iter(struct kiocb * iocb,struct iov_iter * from)296 static ssize_t ext2_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
297 {
298 #ifdef CONFIG_FS_DAX
299 if (IS_DAX(iocb->ki_filp->f_mapping->host))
300 return ext2_dax_write_iter(iocb, from);
301 #endif
302 if (iocb->ki_flags & IOCB_DIRECT)
303 return ext2_dio_write_iter(iocb, from);
304
305 return generic_file_write_iter(iocb, from);
306 }
307
ext2_file_open(struct inode * inode,struct file * filp)308 static int ext2_file_open(struct inode *inode, struct file *filp)
309 {
310 filp->f_mode |= FMODE_CAN_ODIRECT;
311 return dquot_file_open(inode, filp);
312 }
313
314 const struct file_operations ext2_file_operations = {
315 .llseek = generic_file_llseek,
316 .read_iter = ext2_file_read_iter,
317 .write_iter = ext2_file_write_iter,
318 .unlocked_ioctl = ext2_ioctl,
319 #ifdef CONFIG_COMPAT
320 .compat_ioctl = ext2_compat_ioctl,
321 #endif
322 .mmap_prepare = ext2_file_mmap_prepare,
323 .open = ext2_file_open,
324 .release = ext2_release_file,
325 .fsync = ext2_fsync,
326 .get_unmapped_area = thp_get_unmapped_area,
327 .splice_read = filemap_splice_read,
328 .splice_write = iter_file_splice_write,
329 .setlease = generic_setlease,
330 };
331
332 const struct inode_operations ext2_file_inode_operations = {
333 .listxattr = ext2_listxattr,
334 .getattr = ext2_getattr,
335 .setattr = ext2_setattr,
336 .get_inode_acl = ext2_get_acl,
337 .set_acl = ext2_set_acl,
338 .fiemap = ext2_fiemap,
339 .fileattr_get = ext2_fileattr_get,
340 .fileattr_set = ext2_fileattr_set,
341 };
342