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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 ([email protected])
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 * ([email protected])
20 */
21
22#include <linux/time.h>
23#include <linux/pagemap.h>
24#include <linux/filelock.h>
25#include <linux/quotaops.h>
26#include <linux/iomap.h>
27#include <linux/uio.h>
28#include <linux/buffer_head.h>
29#include "ext2.h"
30#include "xattr.h"
31#include "acl.h"
32#include "trace.h"
33
34
35/*
36 * Called when filp is released. This happens when all file descriptors
37 * for a single struct file are closed. Note that different open() calls
38 * for the same file yield different struct file structures.
39 */
40static int ext2_release_file (struct inode * inode, struct file * filp)
41{
42 if (filp->f_mode & FMODE_WRITE) {
43 mutex_lock(&EXT2_I(inode)->truncate_mutex);
44 ext2_discard_reservation(inode);
45 mutex_unlock(&EXT2_I(inode)->truncate_mutex);
46 }
47 return 0;
48}
49
50static ssize_t ext2_dio_read_iter(struct kiocb *iocb, struct iov_iter *to)
51{
52 struct file *file = iocb->ki_filp;
53 struct inode *inode = file->f_mapping->host;
54 ssize_t ret;
55
56 trace_ext2_dio_read_begin(iocb, to, 0);
57 inode_lock_shared(inode);
58 ret = iomap_dio_rw(iocb, to, &ext2_iomap_ops, NULL, 0, NULL, 0);
59 inode_unlock_shared(inode);
60 trace_ext2_dio_read_end(iocb, to, ret);
61
62 return ret;
63}
64
65static int ext2_dio_write_end_io(struct kiocb *iocb, ssize_t size,
66 int error, unsigned int flags)
67{
68 loff_t pos = iocb->ki_pos;
69 struct inode *inode = file_inode(iocb->ki_filp);
70
71 if (error)
72 goto out;
73
74 /*
75 * If we are extending the file, we have to update i_size here before
76 * page cache gets invalidated in iomap_dio_rw(). This prevents racing
77 * buffered reads from zeroing out too much from page cache pages.
78 * Note that all extending writes always happens synchronously with
79 * inode lock held by ext2_dio_write_iter(). So it is safe to update
80 * inode size here for extending file writes.
81 */
82 pos += size;
83 if (pos > i_size_read(inode)) {
84 i_size_write(inode, pos);
85 mark_inode_dirty(inode);
86 }
87out:
88 trace_ext2_dio_write_endio(iocb, size, error);
89 return error;
90}
91
92static const struct iomap_dio_ops ext2_dio_write_ops = {
93 .end_io = ext2_dio_write_end_io,
94};
95
96static ssize_t ext2_dio_write_iter(struct kiocb *iocb, struct iov_iter *from)
97{
98 struct file *file = iocb->ki_filp;
99 struct inode *inode = file->f_mapping->host;
100 ssize_t ret;
101 unsigned int flags = 0;
102 unsigned long blocksize = inode->i_sb->s_blocksize;
103 loff_t offset = iocb->ki_pos;
104 loff_t count = iov_iter_count(from);
105 ssize_t status = 0;
106
107 trace_ext2_dio_write_begin(iocb, from, 0);
108 inode_lock(inode);
109 ret = generic_write_checks(iocb, from);
110 if (ret <= 0)
111 goto out_unlock;
112
113 ret = kiocb_modified(iocb);
114 if (ret)
115 goto out_unlock;
116
117 /* use IOMAP_DIO_FORCE_WAIT for unaligned or extending writes */
118 if (iocb->ki_pos + iov_iter_count(from) > i_size_read(inode) ||
119 (!IS_ALIGNED(iocb->ki_pos | iov_iter_alignment(from), blocksize)))
120 flags |= IOMAP_DIO_FORCE_WAIT;
121
122 ret = iomap_dio_rw(iocb, from, &ext2_iomap_ops, &ext2_dio_write_ops,
123 flags, NULL, 0);
124
125 /* ENOTBLK is magic return value for fallback to buffered-io */
126 if (ret == -ENOTBLK)
127 ret = 0;
128
129 if (ret < 0 && ret != -EIOCBQUEUED)
130 ext2_write_failed(inode->i_mapping, offset + count);
131
132 /* handle case for partial write and for fallback to buffered write */
133 if (ret >= 0 && iov_iter_count(from)) {
134 loff_t pos, endbyte;
135 int ret2;
136
137 iocb->ki_flags &= ~IOCB_DIRECT;
138
139 /*
140 * Prevent concurrent direct I/O and buffered I/O to the same file
141 * range. Wait for in-flight DIO to finish before dirtying pages.
142 */
143 inode_dio_wait(inode);
144
145 pos = iocb->ki_pos;
146 status = generic_perform_write(iocb, from);
147 if (unlikely(status < 0)) {
148 ret = status;
149 goto out_unlock;
150 }
151
152 ret += status;
153 endbyte = pos + status - 1;
154 ret2 = filemap_write_and_wait_range(inode->i_mapping, pos,
155 endbyte);
156 if (!ret2) {
157 invalidate_mapping_pages(inode->i_mapping,
158 pos >> PAGE_SHIFT,
159 endbyte >> PAGE_SHIFT);
160 if (ret > 0)
161 ret = generic_write_sync(iocb, ret);
162 } else {
163 ret = ret2;
164 }
165 }
166
167out_unlock:
168 inode_unlock(inode);
169 if (status)
170 trace_ext2_dio_write_buff_end(iocb, from, status);
171 trace_ext2_dio_write_end(iocb, from, ret);
172 return ret;
173}
174
175static ssize_t ext2_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
176{
177 if (iocb->ki_flags & IOCB_DIRECT)
178 return ext2_dio_read_iter(iocb, to);
179
180 return generic_file_read_iter(iocb, to);
181}
182
183static ssize_t ext2_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
184{
185 if (iocb->ki_flags & IOCB_DIRECT)
186 return ext2_dio_write_iter(iocb, from);
187
188 return generic_file_write_iter(iocb, from);
189}
190
191static int ext2_file_open(struct inode *inode, struct file *filp)
192{
193 filp->f_mode |= FMODE_CAN_ODIRECT;
194 return dquot_file_open(inode, filp);
195}
196
197const struct file_operations ext2_file_operations = {
198 .llseek = generic_file_llseek,
199 .read_iter = ext2_file_read_iter,
200 .write_iter = ext2_file_write_iter,
201 .unlocked_ioctl = ext2_ioctl,
202#ifdef CONFIG_COMPAT
203 .compat_ioctl = ext2_compat_ioctl,
204#endif
205 .mmap_prepare = generic_file_mmap_prepare,
206 .open = ext2_file_open,
207 .release = ext2_release_file,
208 .fsync = simple_fsync,
209 .get_unmapped_area = thp_get_unmapped_area,
210 .splice_read = filemap_splice_read,
211 .splice_write = iter_file_splice_write,
212 .setlease = generic_setlease,
213};
214
215const struct inode_operations ext2_file_inode_operations = {
216 .listxattr = ext2_listxattr,
217 .getattr = ext2_getattr,
218 .setattr = ext2_setattr,
219 .get_inode_acl = ext2_get_acl,
220 .set_acl = ext2_set_acl,
221 .fiemap = ext2_fiemap,
222 .fileattr_get = ext2_fileattr_get,
223 .fileattr_set = ext2_fileattr_set,
224};