From: Anand Jain <anand.jain@oracle.com>
Date: Tue, 2 Apr 2019 18:07:40 +0800
Subject: btrfs: prop: fix vanished compression property after failed set
Git-commit: 272e5326c7837697882ce3162029ba893059b616
Patch-mainline: v5.1-rc5
References: bsc#1182269
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: 63541927c8d1 ("Btrfs: add support for inode properties")
Fixes: 5c1aab1dd544 ("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>
Acked-by: Nikolay Borisov <nborisov@suse.com>
---
fs/btrfs/props.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/fs/btrfs/props.c b/fs/btrfs/props.c
index fd19f3078566..61d22a56c0ba 100644
--- a/fs/btrfs/props.c
+++ b/fs/btrfs/props.c
@@ -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;