btrfs: prop: fix vanished compression property after failed set

The compression property resets to NULL, instead of the old value if we
fail to set the new compression parameter.

  $ btrfs prop get /btrfs compression
    compression=lzo
  $ btrfs prop set /btrfs compression zli
    ERROR: failed to set compression for /btrfs: Invalid argument
  $ btrfs prop get /btrfs compression

This is because the compression property ->validate() is successful for
'zli' as the strncmp() used the length passed from the userspace.

Fix it by using the expected string length in strncmp().

Fixes: 63541927c8 ("Btrfs: add support for inode properties")
Fixes: 5c1aab1dd5 ("btrfs: Add zstd support")
CC: stable@vger.kernel.org # 4.14+
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
Anand Jain 2019-04-02 18:07:40 +08:00 committed by David Sterba
parent 50398fde99
commit 272e5326c7

View File

@ -366,11 +366,11 @@ int btrfs_subvol_inherit_props(struct btrfs_trans_handle *trans,
static int prop_compression_validate(const char *value, size_t len)
{
if (!strncmp("lzo", value, len))
if (!strncmp("lzo", value, 3))
return 0;
else if (!strncmp("zlib", value, len))
else if (!strncmp("zlib", value, 4))
return 0;
else if (!strncmp("zstd", value, len))
else if (!strncmp("zstd", value, 4))
return 0;
return -EINVAL;