]> nv-tegra.nvidia Code Review - linux-2.6.git/blob - fs/ext4/file.c
ext[234]: move over to 'check_acl' permission model
[linux-2.6.git] / 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  */
36 static 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
57 static ssize_t
58 ext4_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
126 force_commit:
127         err = ext4_force_commit(inode->i_sb);
128         if (err)
129                 return err;
130         return ret;
131 }
132
133 static struct vm_operations_struct ext4_file_vm_ops = {
134         .fault          = filemap_fault,
135         .page_mkwrite   = ext4_page_mkwrite,
136 };
137
138 static 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
150 static 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
182 const 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
200 const 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         .check_acl      = ext4_check_acl,
211         .fallocate      = ext4_fallocate,
212         .fiemap         = ext4_fiemap,
213 };
214