storage/posix: Add virtual xattr to fetch path from gfid

The gfid2path infra stores the "pargfid/bname" as on xattr
value for each non directory entry. Hardlinks would have a
separate xattr. This xattr key is internal and is not
exposed to applications.  A virtual xattr is exposed for
the applications to fetch the path from gfid.

Internal xattr:
trusted.gfid2path.<xxhash>

Virtual xattr:
glusterfs.gfidtopath

getfattr -h -n glusterfs.gfidtopath /<aux-mnt>/.gfid/<gfid>

If there are hardlinks, it returns all the paths separated
by ':'.

A volume set option is introduced to change the delimiter
to required string of max length 7.

gluster vol set gfid2path-separator ":::"

Updates: #139
Change-Id: Ie3b0c3fd8bd5333c4a27410011e608333918c02a
Signed-off-by: Kotresh HR <khiremat@redhat.com>
Reviewed-on: https://review.gluster.org/17785
Smoke: Gluster Build System <jenkins@build.gluster.org>
CentOS-regression: Gluster Build System <jenkins@build.gluster.org>
Reviewed-by: Krutika Dhananjay <kdhananj@redhat.com>

1 files changed, 4 insertions, 0 deletions

diff --git a/xlators/storage/posix/src/posix.h b/xlators/storage/posix/src/posix.h
index d83e2678572..3893cf3f9bd 100644
--- a/xlators/storage/posix/src/posix.h
+++ b/xlators/storage/posix/src/posix.h
@@ -173,6 +173,7 @@ struct posix_private {
 	uint32_t        batch_fsync_delay_usec;
         gf_boolean_t    update_pgfid_nlinks;
         gf_boolean_t    gfid2path;
+        char            gfid2path_sep[8];
 
         /* seconds to sleep between health checks */
         uint32_t        health_check_interval;
@@ -300,6 +301,9 @@ posix_get_ancestry (xlator_t *this, inode_t *leaf_inode,
                     dict_t *xdata);
 int
 posix_handle_georep_xattrs (call_frame_t *, const char *, int *, gf_boolean_t);
+int32_t
+posix_resolve_dirgfid_to_path (const uuid_t dirgfid, const char *brick_path,
+                               const char *bname, char **path);
 void
 posix_gfid_unset (xlator_t *this, dict_t *xdata);