3 files changed, 18 insertions, 6 deletions

diff --git a/fs/ceph/caps.c b/fs/ceph/caps.c
index 9fbe9019155c..b01c316a8148 100644
--- a/fs/ceph/caps.c
+++ b/fs/ceph/caps.c
@@ -1195,10 +1195,14 @@ static int __send_cap(struct ceph_mds_client *mdsc, struct ceph_cap *cap,
  * asynchronously back to the MDS once sync writes complete and dirty
  * data is written out.
  *
+ * Unless @again is true, skip cap_snaps that were already sent to
+ * the MDS (i.e., during this session).
+ *
  * Called under i_lock.  Takes s_mutex as needed.
  */
 void __ceph_flush_snaps(struct ceph_inode_info *ci,
-                        struct ceph_mds_session **psession)
+                        struct ceph_mds_session **psession,
+                        int again)
                 __releases(ci->vfs_inode->i_lock)
                 __acquires(ci->vfs_inode->i_lock)
 {
@@ -1240,6 +1244,13 @@ retry:
                         dout("no auth cap (migrating?), doing nothing\n");
                         goto out;
                 }
+
+                /* only flush each capsnap once */
+                if (!again && !list_empty(&capsnap->flushing_item)) {
+                        dout("already flushed %p, skipping\n", capsnap);
+                        continue;
+                }
+
                 mds = ci->i_auth_cap->session->s_mds;
                 mseq = ci->i_auth_cap->mseq;
 
@@ -1314,7 +1325,7 @@ static void ceph_flush_snaps(struct ceph_inode_info *ci)
         struct inode *inode = &ci->vfs_inode;
 
         spin_lock(&inode->i_lock);
-        __ceph_flush_snaps(ci, NULL);
+        __ceph_flush_snaps(ci, NULL, 0);
         spin_unlock(&inode->i_lock);
 }
 
@@ -1477,7 +1488,7 @@ void ceph_check_caps(struct ceph_inode_info *ci, int flags,
 
         /* flush snaps first time around only */
         if (!list_empty(&ci->i_cap_snaps))
-                __ceph_flush_snaps(ci, &session);
+                __ceph_flush_snaps(ci, &session, 0);
         goto retry_locked;
 retry:
         spin_lock(&inode->i_lock);
@@ -1894,7 +1905,7 @@ static void kick_flushing_capsnaps(struct ceph_mds_client *mdsc,
                 if (cap && cap->session == session) {
                         dout("kick_flushing_caps %p cap %p capsnap %p\n", inode,
                              cap, capsnap);
-                        __ceph_flush_snaps(ci, &session);
+                        __ceph_flush_snaps(ci, &session, 1);
                 } else {
                         pr_err("%p auth cap %p not mds%d ???\n", inode,
                                cap, session->s_mds);
diff --git a/fs/ceph/snap.c b/fs/ceph/snap.c
index 9e6eef14b7df..190b6c4a6f2b 100644
--- a/fs/ceph/snap.c
+++ b/fs/ceph/snap.c
@@ -717,7 +717,7 @@ static void flush_snaps(struct ceph_mds_client *mdsc)
                 igrab(inode);
                 spin_unlock(&mdsc->snap_flush_lock);
                 spin_lock(&inode->i_lock);
-                __ceph_flush_snaps(ci, &session);
+                __ceph_flush_snaps(ci, &session, 0);
                 spin_unlock(&inode->i_lock);
                 iput(inode);
                 spin_lock(&mdsc->snap_flush_lock);
diff --git a/fs/ceph/super.h b/fs/ceph/super.h
index c80bfbe27b05..b87638e84c4b 100644
--- a/fs/ceph/super.h
+++ b/fs/ceph/super.h
@@ -828,7 +828,8 @@ extern void ceph_put_cap_refs(struct ceph_inode_info *ci, int had);
 extern void ceph_put_wrbuffer_cap_refs(struct ceph_inode_info *ci, int nr,
                                        struct ceph_snap_context *snapc);
 extern void __ceph_flush_snaps(struct ceph_inode_info *ci,
-                               struct ceph_mds_session **psession);
+                               struct ceph_mds_session **psession,
+                               int again);
 extern void ceph_check_caps(struct ceph_inode_info *ci, int flags,
                             struct ceph_mds_session *session);
 extern void ceph_check_delayed_caps(struct ceph_mds_client *mdsc);