Root/fs/ext4/file.c

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 "ext4.h"
27#include "ext4_jbd2.h"
28#include "xattr.h"
29#include "acl.h"
30
31/*
32 * Called when an inode is released. Note that this is different
33 * from ext4_file_open: open gets called at every open, but release
34 * gets called only when /all/ the files are closed.
35 */
36static int ext4_release_file(struct inode *inode, struct file *filp)
37{
38    if (EXT4_I(inode)->i_state & EXT4_STATE_DA_ALLOC_CLOSE) {
39        ext4_alloc_da_blocks(inode);
40        EXT4_I(inode)->i_state &= ~EXT4_STATE_DA_ALLOC_CLOSE;
41    }
42    /* if we are the last writer on the inode, drop the block reservation */
43    if ((filp->f_mode & FMODE_WRITE) &&
44            (atomic_read(&inode->i_writecount) == 1) &&
45                !EXT4_I(inode)->i_reserved_data_blocks)
46    {
47        down_write(&EXT4_I(inode)->i_data_sem);
48        ext4_discard_preallocations(inode);
49        up_write(&EXT4_I(inode)->i_data_sem);
50    }
51    if (is_dx(inode) && filp->private_data)
52        ext4_htree_free_dir_info(filp->private_data);
53
54    return 0;
55}
56
57static ssize_t
58ext4_file_write(struct kiocb *iocb, const struct iovec *iov,
59        unsigned long nr_segs, loff_t pos)
60{
61    struct file *file = iocb->ki_filp;
62    struct inode *inode = file->f_path.dentry->d_inode;
63    ssize_t ret;
64    int err;
65
66    /*
67     * If we have encountered a bitmap-format file, the size limit
68     * is smaller than s_maxbytes, which is for extent-mapped files.
69     */
70
71    if (!(EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL)) {
72        struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
73        size_t length = iov_length(iov, nr_segs);
74
75        if (pos > sbi->s_bitmap_maxbytes)
76            return -EFBIG;
77
78        if (pos + length > sbi->s_bitmap_maxbytes) {
79            nr_segs = iov_shorten((struct iovec *)iov, nr_segs,
80                          sbi->s_bitmap_maxbytes - pos);
81        }
82    }
83
84    ret = generic_file_aio_write(iocb, iov, nr_segs, pos);
85    /*
86     * Skip flushing if there was an error, or if nothing was written.
87     */
88    if (ret <= 0)
89        return ret;
90
91    /*
92     * If the inode is IS_SYNC, or is O_SYNC and we are doing data
93     * journalling then we need to make sure that we force the transaction
94     * to disk to keep all metadata uptodate synchronously.
95     */
96    if (file->f_flags & O_SYNC) {
97        /*
98         * If we are non-data-journaled, then the dirty data has
99         * already been flushed to backing store by generic_osync_inode,
100         * and the inode has been flushed too if there have been any
101         * modifications other than mere timestamp updates.
102         *
103         * Open question --- do we care about flushing timestamps too
104         * if the inode is IS_SYNC?
105         */
106        if (!ext4_should_journal_data(inode))
107            return ret;
108
109        goto force_commit;
110    }
111
112    /*
113     * So we know that there has been no forced data flush. If the inode
114     * is marked IS_SYNC, we need to force one ourselves.
115     */
116    if (!IS_SYNC(inode))
117        return ret;
118
119    /*
120     * Open question #2 --- should we force data to disk here too? If we
121     * don't, the only impact is that data=writeback filesystems won't
122     * flush data to disk automatically on IS_SYNC, only metadata (but
123     * historically, that is what ext2 has done.)
124     */
125
126force_commit:
127    err = ext4_force_commit(inode->i_sb);
128    if (err)
129        return err;
130    return ret;
131}
132
133static struct vm_operations_struct ext4_file_vm_ops = {
134    .fault = filemap_fault,
135    .page_mkwrite = ext4_page_mkwrite,
136};
137
138static int ext4_file_mmap(struct file *file, struct vm_area_struct *vma)
139{
140    struct address_space *mapping = file->f_mapping;
141
142    if (!mapping->a_ops->readpage)
143        return -ENOEXEC;
144    file_accessed(file);
145    vma->vm_ops = &ext4_file_vm_ops;
146    vma->vm_flags |= VM_CAN_NONLINEAR;
147    return 0;
148}
149
150static int ext4_file_open(struct inode * inode, struct file * filp)
151{
152    struct super_block *sb = inode->i_sb;
153    struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
154    struct vfsmount *mnt = filp->f_path.mnt;
155    struct path path;
156    char buf[64], *cp;
157
158    if (unlikely(!(sbi->s_mount_flags & EXT4_MF_MNTDIR_SAMPLED) &&
159             !(sb->s_flags & MS_RDONLY))) {
160        sbi->s_mount_flags |= EXT4_MF_MNTDIR_SAMPLED;
161        /*
162         * Sample where the filesystem has been mounted and
163         * store it in the superblock for sysadmin convenience
164         * when trying to sort through large numbers of block
165         * devices or filesystem images.
166         */
167        memset(buf, 0, sizeof(buf));
168        path.mnt = mnt->mnt_parent;
169        path.dentry = mnt->mnt_mountpoint;
170        path_get(&path);
171        cp = d_path(&path, buf, sizeof(buf));
172        path_put(&path);
173        if (!IS_ERR(cp)) {
174            memcpy(sbi->s_es->s_last_mounted, cp,
175                   sizeof(sbi->s_es->s_last_mounted));
176            sb->s_dirt = 1;
177        }
178    }
179    return generic_file_open(inode, filp);
180}
181
182const struct file_operations ext4_file_operations = {
183    .llseek = generic_file_llseek,
184    .read = do_sync_read,
185    .write = do_sync_write,
186    .aio_read = generic_file_aio_read,
187    .aio_write = ext4_file_write,
188    .unlocked_ioctl = ext4_ioctl,
189#ifdef CONFIG_COMPAT
190    .compat_ioctl = ext4_compat_ioctl,
191#endif
192    .mmap = ext4_file_mmap,
193    .open = ext4_file_open,
194    .release = ext4_release_file,
195    .fsync = ext4_sync_file,
196    .splice_read = generic_file_splice_read,
197    .splice_write = generic_file_splice_write,
198};
199
200const struct inode_operations ext4_file_inode_operations = {
201    .truncate = ext4_truncate,
202    .setattr = ext4_setattr,
203    .getattr = ext4_getattr,
204#ifdef CONFIG_EXT4_FS_XATTR
205    .setxattr = generic_setxattr,
206    .getxattr = generic_getxattr,
207    .listxattr = ext4_listxattr,
208    .removexattr = generic_removexattr,
209#endif
210    .permission = ext4_permission,
211    .fallocate = ext4_fallocate,
212    .fiemap = ext4_fiemap,
213};
214
215

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