uss/gluster: generate gfid for snapshot files from snapname and gfid

This is a backport of http://review.gluster.org/#/c/9255/

If 'a' and 'b' are hardlinks, we need to generate a virtual
gfid for these files so that the inode number for 'a' and 'b'
are same.

Generate gfid as below:
gfid_of_a = MD5(snapname + back_end_gfid(a))
if '/dir1/a' and '/dir2/b' are hardlinks, then inode number should be
same for
all below files:
/mnt/.snaps/snap1/dir1/a
/mnt/.snaps/snap1/dir2/b
/mnt/dir1/.snaps/snap1/a
/mnt/dir2/.snaps/snap1/b

> Change-Id: Ifda793455610e554f3f1e4cbb90d44c02cda4b0f
> BUG: 1171703
> Signed-off-by: vmallika <vmallika@redhat.com>

Change-Id: I917b2fe2915d88f69700bc8c3283e9c613e13bb8
BUG: 1316099
Signed-off-by: vmallika <vmallika@redhat.com>
Reviewed-on: http://review.gluster.org/13656
Smoke: Gluster Build System <jenkins@build.gluster.com>
NetBSD-regression: NetBSD Build System <jenkins@build.gluster.org>
CentOS-regression: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Rajesh Joseph <rjoseph@redhat.com>

1 files changed, 15 insertions, 0 deletions

diff --git a/xlators/features/snapview-server/src/snapview-server-helpers.c b/xlators/features/snapview-server/src/snapview-server-helpers.c
index 92ffdf512ef..0303f4d6df6 100644
--- a/xlators/features/snapview-server/src/snapview-server-helpers.c
+++ b/xlators/features/snapview-server/src/snapview-server-helpers.c
@@ -335,6 +335,21 @@ out:
 }
 
 void
+svs_uuid_generate (uuid_t gfid, char *snapname, uuid_t origin_gfid)
+{
+        unsigned char md5_sum[MD5_DIGEST_LENGTH] = {0};
+        char          ino_string[NAME_MAX + 32]  = "";
+        int           ret                        = 0;
+
+        GF_ASSERT (snapname);
+
+        ret = snprintf (ino_string, sizeof (ino_string), "%s%s",
+                        snapname, uuid_utoa(origin_gfid));
+        MD5((unsigned char *)ino_string, strlen(ino_string), md5_sum);
+        gf_uuid_copy (gfid, md5_sum);
+}
+
+void
 svs_fill_ino_from_gfid (struct iatt *buf)
 {
         uint64_t  temp_ino = 0;