tree cb944c5cd124ed8b1d57fdd4cba2f22cff03723c
parent 6893162215d7bf08a4273247ec1fc7dedee5135c
author Yan, Zheng <zyan@redhat.com> 1437358446 +0800
committer Ilya Dryomov <idryomov@gmail.com> 1441743269 +0300

ceph: fix queuing inode to mdsdir's snaprealm

During MDS failovers, MClientSnap message may cause kclient to move
some inodes from root directory's snaprealm to mdsdir's snaprealm
and queue snapshots for these inodes. For a FS has never created any
snapshot, both root directory's snaprealm and mdsdir's snaprealm
share the same snapshot contexts (both are ceph_empty_snapc). This
confuses ceph_put_wrbuffer_cap_refs(), make it unable to distinguish
snapshot buffers from head buffers.

The fix is do not use ceph_empty_snapc as snaprealm's cached context.

Signed-off-by: Yan, Zheng <zyan@redhat.com>