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Commit 7c83f5cb authored by Artem Bityutskiy's avatar Artem Bityutskiy
Browse files

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: default avatarArtem Bityutskiy <Artem.Bityutskiy@nokia.com>
parent 8eec2f36

fs/ubifs/super.c

+4 −17
Original line number Diff line number Diff line
@@ -1945,7 +1945,6 @@ static int ubifs_fill_super(struct super_block *sb, void *data, int silent) 
	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 ubifs_fill_super(struct super_block *sb, void *data, int silent) 
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 @@ static int ubifs_get_sb(struct file_system_type *fs_type, int flags, 


	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 @@ static int ubifs_get_sb(struct file_system_type *fs_type, int flags, 
	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,

};



/*