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/ext4_fs.h>
25 #include <linux/ext4_jbd2.h>
26 #include "xattr.h"
27 #include "acl.h"
28
29 /*
30 * Called when an inode is released. Note that this is different
31 * from ext4_file_open: open gets called at every open, but release
32 * gets called only when /all/ the files are closed.
33 */
34 static int ext4_release_file (struct inode * inode, struct file * filp)
35 {
36 /* if we are the last writer on the inode, drop the block reservation */
37 if ((filp->f_mode & FMODE_WRITE) &&
38 (atomic_read(&inode->i_writecount) == 1))
39 {
40 down_write(&EXT4_I(inode)->i_data_sem);
41 ext4_discard_reservation(inode);
42 up_write(&EXT4_I(inode)->i_data_sem);
43 }
44 if (is_dx(inode) && filp->private_data)
45 ext4_htree_free_dir_info(filp->private_data);
46
47 return 0;
48 }
49
50 static ssize_t
51 ext4_file_write(struct kiocb *iocb, const struct iovec *iov,
52 unsigned long nr_segs, loff_t pos)
53 {
54 struct file *file = iocb->ki_filp;
55 struct inode *inode = file->f_path.dentry->d_inode;
56 ssize_t ret;
57 int err;
58
59 /*
60 * If we have encountered a bitmap-format file, the size limit
61 * is smaller than s_maxbytes, which is for extent-mapped files.
62 */
63
64 if (!(EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL)) {
65 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
66 size_t length = iov_length(iov, nr_segs);
67
68 if (pos > sbi->s_bitmap_maxbytes)
69 return -EFBIG;
70
71 if (pos + length > sbi->s_bitmap_maxbytes) {
72 nr_segs = iov_shorten((struct iovec *)iov, nr_segs,
73 sbi->s_bitmap_maxbytes - pos);
74 }
75 }
76
77 ret = generic_file_aio_write(iocb, iov, nr_segs, pos);
78 /*
79 * Skip flushing if there was an error, or if nothing was written.
80 */
81 if (ret <= 0)
82 return ret;
83
84 /*
85 * If the inode is IS_SYNC, or is O_SYNC and we are doing data
86 * journalling then we need to make sure that we force the transaction
87 * to disk to keep all metadata uptodate synchronously.
88 */
89 if (file->f_flags & O_SYNC) {
90 /*
91 * If we are non-data-journaled, then the dirty data has
92 * already been flushed to backing store by generic_osync_inode,
93 * and the inode has been flushed too if there have been any
94 * modifications other than mere timestamp updates.
95 *
96 * Open question --- do we care about flushing timestamps too
97 * if the inode is IS_SYNC?
98 */
99 if (!ext4_should_journal_data(inode))
100 return ret;
101
102 goto force_commit;
103 }
104
105 /*
106 * So we know that there has been no forced data flush. If the inode
107 * is marked IS_SYNC, we need to force one ourselves.
108 */
109 if (!IS_SYNC(inode))
110 return ret;
111
112 /*
113 * Open question #2 --- should we force data to disk here too? If we
114 * don't, the only impact is that data=writeback filesystems won't
115 * flush data to disk automatically on IS_SYNC, only metadata (but
116 * historically, that is what ext2 has done.)
117 */
118
119 force_commit:
120 err = ext4_force_commit(inode->i_sb);
121 if (err)
122 return err;
123 return ret;
124 }
125
126 const struct file_operations ext4_file_operations = {
127 .llseek = generic_file_llseek,
128 .read = do_sync_read,
129 .write = do_sync_write,
130 .aio_read = generic_file_aio_read,
131 .aio_write = ext4_file_write,
132 .ioctl = ext4_ioctl,
133 #ifdef CONFIG_COMPAT
134 .compat_ioctl = ext4_compat_ioctl,
135 #endif
136 .mmap = generic_file_mmap,
137 .open = generic_file_open,
138 .release = ext4_release_file,
139 .fsync = ext4_sync_file,
140 .splice_read = generic_file_splice_read,
141 .splice_write = generic_file_splice_write,
142 };
143
144 const struct inode_operations ext4_file_inode_operations = {
145 .truncate = ext4_truncate,
146 .setattr = ext4_setattr,
147 #ifdef CONFIG_EXT4DEV_FS_XATTR
148 .setxattr = generic_setxattr,
149 .getxattr = generic_getxattr,
150 .listxattr = ext4_listxattr,
151 .removexattr = generic_removexattr,
152 #endif
153 .permission = ext4_permission,
154 .fallocate = ext4_fallocate,
155 };
156
157
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