queue-4.19/btrfs-prop-fix-vanished-compression-property-after-failed-set.patch

   1 From 272e5326c7837697882ce3162029ba893059b616 Mon Sep 17 00:00:00 2001
   2 From: Anand Jain <anand.jain@oracle.com>
   3 Date: Tue, 2 Apr 2019 18:07:40 +0800
   4 Subject: btrfs: prop: fix vanished compression property after failed set
   5
   6 From: Anand Jain <anand.jain@oracle.com>
   7
   8 commit 272e5326c7837697882ce3162029ba893059b616 upstream.
   9
  10 The compression property resets to NULL, instead of the old value if we
  11 fail to set the new compression parameter.
  12
  13   $ btrfs prop get /btrfs compression
  14     compression=lzo
  15   $ btrfs prop set /btrfs compression zli
  16     ERROR: failed to set compression for /btrfs: Invalid argument
  17   $ btrfs prop get /btrfs compression
  18
  19 This is because the compression property ->validate() is successful for
  20 'zli' as the strncmp() used the length passed from the userspace.
  21
  22 Fix it by using the expected string length in strncmp().
  23
  24 Fixes: 63541927c8d1 ("Btrfs: add support for inode properties")
  25 Fixes: 5c1aab1dd544 ("btrfs: Add zstd support")
  26 CC: stable@vger.kernel.org # 4.14+
  27 Reviewed-by: Nikolay Borisov <nborisov@suse.com>
  28 Signed-off-by: Anand Jain <anand.jain@oracle.com>
  29 Reviewed-by: David Sterba <dsterba@suse.com>
  30 Signed-off-by: David Sterba <dsterba@suse.com>
  31 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  32
  33 ---
  34  fs/btrfs/props.c |    6 +++---
  35  1 file changed, 3 insertions(+), 3 deletions(-)
  36
  37 --- a/fs/btrfs/props.c
  38 +++ b/fs/btrfs/props.c
  39 @@ -366,11 +366,11 @@ int btrfs_subvol_inherit_props(struct bt
  40
  41  static int prop_compression_validate(const char *value, size_t len)
  42  {
  43 -       if (!strncmp("lzo", value, len))
  44 +       if (!strncmp("lzo", value, 3))
  45                 return 0;
  46 -       else if (!strncmp("zlib", value, len))
  47 +       else if (!strncmp("zlib", value, 4))
  48                 return 0;
  49 -       else if (!strncmp("zstd", value, len))
  50 +       else if (!strncmp("zstd", value, 4))
  51                 return 0;
  52
  53         return -EINVAL;