ceph: fix cache revoke race

handle following sequence of events:

- non-auth MDS revokes Fc cap. queue invalidate work
- auth MDS issues Fc cap through request reply. i_rdcache_gen gets
  increased.
- invalidate work runs. it finds i_rdcache_revoking != i_rdcache_gen,
  so it does nothing.

Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>

1 files changed, 5 insertions, 3 deletions

diff --git a/fs/ceph/inode.c b/fs/ceph/inode.c
index a808bfb..3db97ba 100644
--- a/fs/ceph/inode.c
+++ b/fs/ceph/inode.c
@@ -1466,7 +1466,8 @@ static void ceph_invalidate_work(struct work_struct *work)
 	dout("invalidate_pages %p gen %d revoking %d\n", inode,
 	     ci->i_rdcache_gen, ci->i_rdcache_revoking);
 	if (ci->i_rdcache_revoking != ci->i_rdcache_gen) {
-		/* nevermind! */
+		if (__ceph_caps_revoking_other(ci, NULL, CEPH_CAP_FILE_CACHE))
+			check = 1;
 		spin_unlock(&ci->i_ceph_lock);
 		mutex_unlock(&ci->i_truncate_mutex);
 		goto out;
@@ -1487,13 +1488,14 @@ static void ceph_invalidate_work(struct work_struct *work)
 		dout("invalidate_pages %p gen %d raced, now %d revoking %d\n",
 		     inode, orig_gen, ci->i_rdcache_gen,
 		     ci->i_rdcache_revoking);
+		if (__ceph_caps_revoking_other(ci, NULL, CEPH_CAP_FILE_CACHE))
+			check = 1;
 	}
 	spin_unlock(&ci->i_ceph_lock);
 	mutex_unlock(&ci->i_truncate_mutex);
-
+out:
 	if (check)
 		ceph_check_caps(ci, 0, NULL);
-out:
 	iput(inode);
 }