ceph: fix freeing inode vs removing session caps race

remove_session_caps() uses iterate_session_caps() to remove caps,
but iterate_session_caps() skips inodes that are being deleted.
So session->s_nr_caps can be non-zero after iterate_session_caps()
return.

We can fix the issue by waiting until deletions are complete.
__wait_on_freeing_inode() is designed for the job, but it is not
exported, so we use lookup inode function to access it.

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

1 files changed, 8 insertions, 0 deletions

diff --git a/fs/ceph/inode.c b/fs/ceph/inode.c
index 55aaddb4047..3b0abed667c 100644
--- a/fs/ceph/inode.c
+++ b/fs/ceph/inode.c
@@ -61,6 +61,14 @@ struct inode *ceph_get_inode(struct super_block *sb, struct ceph_vino vino)
 	return inode;
 }
 
+struct inode *ceph_lookup_inode(struct super_block *sb, struct ceph_vino vino)
+{
+	struct inode *inode;
+	ino_t t = ceph_vino_to_ino(vino);
+	inode = ilookup5_nowait(sb, t, ceph_ino_compare, &vino);
+	return inode;
+}
+
 /*
  * get/constuct snapdir inode for a given directory
  */