On Wed, Mar 13, 2019 at 04:49:54PM +0800, Anand Jain wrote: > > > On 3/13/19 3:22 PM, Nikolay Borisov wrote: > > > > > > On 13.03.19 г. 9:20 ч., Nikolay Borisov wrote: > >> > >> > >> 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 <[email protected]> > >>> --- > >>> 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. > > Its part of the 'struct prop_handler', its better to keep it until > properties have completely evolved. > > > > > As a matter of fact I don't see any value in prop_compression_validate > > since the exact same code is used in prop_compression_apply and einval > > will be returned if an invalid value is passed in. > > I notice too. But its better to keep it until the most of the > properties have evolved. > > As of now btrfs_set_prop() follows sequence.. > h->validate(prop) > setxattr(prop) > h->apply(prop) > > If validate fails its easy to fail exit.
Agreed, some code could be repeated in the apply() callback, but otherwise I'd like to keep both.
