cluster/dht: Prevent dht_access from going into a loop.

If access fails with ENOTCONN, do not wind to same subvol.
We wind to first-up-subvol if access fails with ENOTCONN.
In few cases, if dht has only 1 subvolume, and access fails with
ENOTCONN, we go into a infinite loop of winding to same subvol

The fix is to check if we previously wound to same subvol, and
fail if first-up-subvol is same.

Change-Id: Ib5d3ce7d33e8ea09147905a7df1ed280874fa549
BUG: 1139996
Signed-off-by: shishir gowda <sgowda@redhat.com>
Reviewed-on: http://review.gluster.org/5319
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Anand Avati <avati@redhat.com>
Reviewed-on: http://review.gluster.org/8677
Reviewed-by: N Balachandran <nbalacha@redhat.com>
Reviewed-by: Kaleb KEITHLEY <kkeithle@redhat.com>
cluster/dht: Fix dht_access treating directory like files

When the cluster topology changes due to add-brick, all sub
volumes of DHT will not contain the directories till a rebalance
is completed. Till the rebalance is run, if a caller bypasses
lookup and calls access due to saved/cached inode information
(like NFS server does) then, dht_access misreads the error
(ESTALE/ENOENT) from the new subvolumes and incorrectly tries
to handle the inode as a file. This results in the directories
in memory state in DHT to be corrupted and not heal even post
a rebalance.

This commit fixes the problem in dht_access thereby preventing
DHT from misrepresenting a directory as a file in the case
presented above.

Change-Id: Idcdaa3837db71c8fe0a40ec0084a6c3dbe27e772
BUG: 1139997
Signed-off-by: Shyam <srangana@redhat.com>
Reviewed-on: http://review.gluster.org/8462
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Vijay Bellur <vbellur@redhat.com>
Reviewed-on: http://review.gluster.org/8678
Reviewed-by: Kaleb KEITHLEY <kkeithle@redhat.com>