On 13.03.19 г. 7:36 ч., Anand Jain wrote:
> 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 len passed from the userland.
>
> Fix it by using the expected string length in strncmp().
>
> Signed-off-by: Anand Jain <anand.jain@xxxxxxxxxx>
> ---
> 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 ef6502a94712..7aa362c2fbcf 100644
> --- a/fs/btrfs/props.c
> +++ b/fs/btrfs/props.c
> @@ -277,11 +277,11 @@ static int prop_compression_validate(struct inode *inode, const char *value,
> if (!value)
> return 0;
>
> - 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;
This also makes the len argument to prop_compression_validate redundant
and should be removed as well.
>
> return -EINVAL;
>
