performance/md-cache: Do not skip caching of null character xattr values

Null character string is a valid xattr value in file system. But for
those xattrs processed by md-cache, it does not update its entries if
value is null('\0'). This results in ENODATA when those xattrs are
queried afterwards via getxattr() causing failures in basic operations
like create, copy etc in a specially configured Samba setup for Mac OS
clients.

On the other side snapview-server is internally setting empty string("")
as value for xattrs received as part of listxattr() and are not intended
to be cached. Therefore we try to maintain that behaviour using an
additional dictionary key to prevent updation of entries in getxattr()
and fgetxattr() callbacks in md-cache.

Credits: Poornima G <pgurusid@redhat.com>

Change-Id: I7859cbad0a06ca6d788420c2a495e658699c6ff7
Fixes: bz#1726205
Signed-off-by: Anoop C S <anoopcs@redhat.com>

0 files changed, 0 insertions, 0 deletions