cluster/dht : User xattrs are not healed after brick stop/start

Problem: In a distributed volume custom extended attribute value for a directory
         does not display correct value after stop/start or added newly brick.
         If any extended(acl) attribute value is set for a directory after stop/added
         the brick the attribute(user|acl|quota) value is not updated on brick
         after start the brick.

Solution: First store hashed subvol or subvol(has internal xattr) on inode ctx and
          consider it as a MDS subvol.At the time of update custom xattr
          (user,quota,acl, selinux) on directory first check the mds from
          inode ctx, if mds is not present on inode ctx then throw EINVAL error
          to application otherwise set xattr on MDS subvol with internal xattr
          value of -1 and then try to update the attribute on other non MDS
          volumes also.If mds subvol is down in that case throw an
          error "Transport endpoint is not connected". In dht_dir_lookup_cbk|
          dht_revalidate_cbk|dht_discover_complete call dht_call_dir_xattr_heal
          to heal custom extended attribute.
          In case of gnfs server if hashed subvol has not found based on
          loc then wind a call on all subvol to update xattr.

Fix:    1) Save MDS subvol on inode ctx
        2) Check if mds subvol is present on inode ctx
        3) If mds subvol is down then call unwind with error ENOTCONN and if it is up
           then set new xattr "GF_DHT_XATTR_MDS" to -1 and wind a call on other
           subvol.
        4) If setxattr fop is successful on non-mds subvol then increment the value of
           internal xattr to +1
        5) At the time of directory_lookup check the value of new xattr GF_DHT_XATTR_MDS
        6) If value is not 0 in dht_lookup_dir_cbk(other cbk) functions then call heal
           function to heal user xattr
        7) syncop_setxattr on hashed_subvol to reset the value of xattr to 0
           if heal is successful on all subvol.

Test : To reproduce the issue followed below steps
       1) Create a distributed volume and create mount point
       2) Create some directory from mount point mkdir tmp{1..5}
       3) Kill any one brick from the volume
       4) Set extended attribute from mount point on directory
          setfattr -n user.foo -v "abc" ./tmp{1..5}
          It will throw error " Transport End point is not connected "
          for those hashed subvol is down
       5) Start volume with force option to start brick process
       6) Execute getfattr command on mount point for directory
       7) Check extended attribute on brick
          getfattr -n user.foo <volume-location>/tmp{1..5}
          It shows correct value for directories for those
          xattr fop were executed successfully.

Note: The patch will resolve xattr healing problem only for fuse mount
      not for nfs mount.

BUG: 1371806
Signed-off-by: Mohit Agrawal <moagrawa@redhat.com>

Change-Id: I4eb137eace24a8cb796712b742f1d177a65343d5

1 files changed, 2 insertions, 0 deletions

diff --git a/xlators/cluster/dht/src/dht-shared.c b/xlators/cluster/dht/src/dht-shared.c
index 0373ebffe5a..42daff01489 100644
--- a/xlators/cluster/dht/src/dht-shared.c
+++ b/xlators/cluster/dht/src/dht-shared.c
@@ -868,6 +868,7 @@ dht_init (xlator_t *this)
         }
 
         GF_OPTION_INIT ("xattr-name", conf->xattr_name, str, err);
+        gf_asprintf (&conf->mds_xattr_key, "%s."DHT_MDS_STR, conf->xattr_name);
         gf_asprintf (&conf->link_xattr_name, "%s."DHT_LINKFILE_STR,
                      conf->xattr_name);
         gf_asprintf (&conf->commithash_xattr_name, "%s."DHT_COMMITHASH_STR,
@@ -917,6 +918,7 @@ err:
                 GF_FREE (conf->xattr_name);
                 GF_FREE (conf->link_xattr_name);
                 GF_FREE (conf->wild_xattr_name);
+                GF_FREE (conf->mds_xattr_key);
 
                 if (conf->lock_pool)
                         mem_pool_destroy (conf->lock_pool);