UBIFS: use anonymous device
UBIFS has erroneuosly set 'sb->s_dev' to the UBI volume
character device major/minor. This may lead to clashes
if there is another FS mounted to a block device with
the same major/minor numbers. User-space programs which
use 'stat->st_dev' may get confused because of this.
This problem was found by Al Viro. He also pointed the
way to fix the problem - use 'set_anon_super()' and
'kill_anon_super()' VFS helpers.
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
diff --git a/fs/ubifs/super.c b/fs/ubifs/super.c
index 052514c..42b818d 100644
--- a/fs/ubifs/super.c
+++ b/fs/ubifs/super.c
@@ -1945,7 +1945,6 @@
sb->s_magic = UBIFS_SUPER_MAGIC;
sb->s_blocksize = UBIFS_BLOCK_SIZE;
sb->s_blocksize_bits = UBIFS_BLOCK_SHIFT;
- sb->s_dev = c->vi.cdev;
sb->s_maxbytes = c->max_inode_sz = key_max_inode_size(c);
if (c->max_inode_sz > MAX_LFS_FILESIZE)
sb->s_maxbytes = c->max_inode_sz = MAX_LFS_FILESIZE;
@@ -1990,16 +1989,9 @@
static int sb_test(struct super_block *sb, void *data)
{
dev_t *dev = data;
+ struct ubifs_info *c = sb->s_fs_info;
- return sb->s_dev == *dev;
-}
-
-static int sb_set(struct super_block *sb, void *data)
-{
- dev_t *dev = data;
-
- sb->s_dev = *dev;
- return 0;
+ return c->vi.cdev == *dev;
}
static int ubifs_get_sb(struct file_system_type *fs_type, int flags,
@@ -2027,7 +2019,7 @@
dbg_gen("opened ubi%d_%d", vi.ubi_num, vi.vol_id);
- sb = sget(fs_type, &sb_test, &sb_set, &vi.cdev);
+ sb = sget(fs_type, &sb_test, &set_anon_super, &vi.cdev);
if (IS_ERR(sb)) {
err = PTR_ERR(sb);
goto out_close;
@@ -2068,16 +2060,11 @@
return err;
}
-static void ubifs_kill_sb(struct super_block *sb)
-{
- generic_shutdown_super(sb);
-}
-
static struct file_system_type ubifs_fs_type = {
.name = "ubifs",
.owner = THIS_MODULE,
.get_sb = ubifs_get_sb,
- .kill_sb = ubifs_kill_sb
+ .kill_sb = kill_anon_super,
};
/*