dht/tier :rename fails with EBUSY

When the files was in hot tier and the look up was done already, then
hashed and cached subvolume will be hot-tier. Once the file is moved
from hot-tier to cold-tier, then subsequent lookup will send a
revalidate lookup to hot-tier and it will find out that the file was
actually moved and there is only link in the cached subvolume. So dht
will return an ESTALE to fuse. Upon receiving ESTALE for a lookup, fuse
will create a new inode and sent a fresh lookup. This lookup will be
successful, and it will locate the file properly. Then fuse try to link
the inode, but the older inode was already there in inmemory inode cache
with same gfid and that is also shared with fuse kernal. So inode_link
will return the older ionode itself. So the subsequent rename fop will
come to gluster with the older inode. From dht_rename, we will take a
lock on the inode and after successful inodelk on inode dht will send
lookup before creating a link. this lookup will again find out that the
file is a link file, and then dht will think that file is
migrating/migrated in the mean time, and will send EBUSY.

Change-Id: Ib3a01e5b1d7f64514b04bb6234026d049f082679
BUG: 1248306
Signed-off-by: Mohammed Rafi KC <rkavunga@redhat.com>
Reviewed-on: http://review.gluster.org/11768
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Raghavendra G <rgowdapp@redhat.com>
Reviewed-by: Dan Lambright <dlambrig@redhat.com>
Tested-by: NetBSD Build System <jenkins@build.gluster.org>
Tested-by: Dan Lambright <dlambrig@redhat.com>

1 files changed, 20 insertions, 8 deletions

diff --git a/xlators/cluster/dht/src/dht-common.c b/xlators/cluster/dht/src/dht-common.c
index 95a9d6c4cee..a4e0afa4316 100644
--- a/xlators/cluster/dht/src/dht-common.c
+++ b/xlators/cluster/dht/src/dht-common.c
@@ -676,10 +676,12 @@ dht_revalidate_cbk (call_frame_t *frame, void *cookie, xlator_t *this,
         int           ret  = -1;
         int           is_dir = 0;
         int           is_linkfile = 0;
+        int           follow_link = 0;
         call_frame_t *copy          = NULL;
         dht_local_t  *copy_local    = NULL;
         char gfid[GF_UUID_BUF_SIZE] = {0};
         uint32_t      vol_commit_hash = 0;
+        xlator_t      *subvol = NULL;
 
         GF_VALIDATE_OR_GOTO ("dht", frame, err);
         GF_VALIDATE_OR_GOTO ("dht", this, err);
@@ -770,17 +772,10 @@ dht_revalidate_cbk (call_frame_t *frame, void *cookie, xlator_t *this,
                 is_dir = check_is_dir (inode, stbuf, xattr);
                 is_linkfile = check_is_linkfile (inode, stbuf, xattr,
                                                  conf->link_xattr_name);
-
                 if (is_linkfile) {
-                        gf_msg (this->name, GF_LOG_INFO, 0,
-                                DHT_MSG_REVALIDATE_CBK_INFO,
-                                "Revalidate: linkfile found %s, (gfid = %s)",
-                                local->loc.path, gfid);
-                        local->return_estale = 1;
-
+                        follow_link = 1;
                         goto unlock;
                 }
-
                 if (is_dir) {
                         ret = dht_dir_has_layout (xattr, conf->xattr_name);
                         if (ret >= 0) {
@@ -828,6 +823,23 @@ dht_revalidate_cbk (call_frame_t *frame, void *cookie, xlator_t *this,
         }
 unlock:
         UNLOCK (&frame->lock);
+
+        if (follow_link) {
+                gf_uuid_copy (local->gfid, stbuf->ia_gfid);
+
+                subvol = dht_linkfile_subvol (this, inode, stbuf, xattr);
+                if (!subvol) {
+                        op_errno = ESTALE;
+                        local->op_ret = -1;
+                } else {
+
+                        STACK_WIND (frame, dht_lookup_linkfile_cbk,
+                        subvol, subvol->fops->lookup,
+                        &local->loc, local->xattr_req);
+                        return 0;
+                }
+        }
+
 out:
         this_call_cnt = dht_frame_return (frame);