ceph: make sure syncfs flushes all cap snaps

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

4 files changed, 76 insertions, 31 deletions

diff --git a/fs/ceph/caps.c b/fs/ceph/caps.c
index 900c05fd77d8..bbd969e16a01 100644
--- a/fs/ceph/caps.c
+++ b/fs/ceph/caps.c
@@ -1259,14 +1259,14 @@ 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
+ * Unless @kick is true, skip cap_snaps that were already sent to
  * the MDS (i.e., during this session).
  *
  * Called under i_ceph_lock.  Takes s_mutex as needed.
  */
 void __ceph_flush_snaps(struct ceph_inode_info *ci,
                         struct ceph_mds_session **psession,
-                        int again)
+                        int kick)
                 __releases(ci->i_ceph_lock)
                 __acquires(ci->i_ceph_lock)
 {
@@ -1307,7 +1307,7 @@ retry:
                 }
 
                 /* only flush each capsnap once */
-                if (!again && !list_empty(&capsnap->flushing_item)) {
+                if (!kick && !list_empty(&capsnap->flushing_item)) {
                         dout("already flushed %p, skipping\n", capsnap);
                         continue;
                 }
@@ -1317,6 +1317,9 @@ retry:
 
                 if (session && session->s_mds != mds) {
                         dout("oops, wrong session %p mutex\n", session);
+                        if (kick)
+                                goto out;
+
                         mutex_unlock(&session->s_mutex);
                         ceph_put_mds_session(session);
                         session = NULL;
@@ -1342,10 +1345,9 @@ retry:
 
                 capsnap->flush_tid = ++ci->i_cap_flush_last_tid;
                 atomic_inc(&capsnap->nref);
-                if (!list_empty(&capsnap->flushing_item))
-                        list_del_init(&capsnap->flushing_item);
-                list_add_tail(&capsnap->flushing_item,
-                              &session->s_cap_snaps_flushing);
+                if (list_empty(&capsnap->flushing_item))
+                        list_add_tail(&capsnap->flushing_item,
+                                      &session->s_cap_snaps_flushing);
                 spin_unlock(&ci->i_ceph_lock);
 
                 dout("flush_snaps %p cap_snap %p follows %lld tid %llu\n",
@@ -2876,6 +2878,7 @@ static void handle_cap_flushsnap_ack(struct inode *inode, u64 flush_tid,
                                      struct ceph_mds_session *session)
 {
         struct ceph_inode_info *ci = ceph_inode(inode);
+        struct ceph_mds_client *mdsc = ceph_sb_to_client(inode->i_sb)->mdsc;
         u64 follows = le64_to_cpu(m->snap_follows);
         struct ceph_cap_snap *capsnap;
         int drop = 0;
@@ -2899,6 +2902,7 @@ static void handle_cap_flushsnap_ack(struct inode *inode, u64 flush_tid,
                         list_del(&capsnap->ci_item);
                         list_del(&capsnap->flushing_item);
                         ceph_put_cap_snap(capsnap);
+                        wake_up_all(&mdsc->cap_flushing_wq);
                         drop = 1;
                         break;
                 } else {
diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c
index 88010f9a254d..2bb9264b9225 100644
--- a/fs/ceph/mds_client.c
+++ b/fs/ceph/mds_client.c
@@ -1488,17 +1488,22 @@ out_unlocked:
         return err;
 }
 
-static int check_cap_flush(struct inode *inode, u64 want_flush_seq)
+static int check_cap_flush(struct ceph_inode_info *ci,
+                           u64 want_flush_seq, u64 want_snap_seq)
 {
-        struct ceph_inode_info *ci = ceph_inode(inode);
-        int ret;
+        int ret1 = 1, ret2 = 1;
         spin_lock(&ci->i_ceph_lock);
-        if (ci->i_flushing_caps)
-                ret = ci->i_cap_flush_seq >= want_flush_seq;
-        else
-                ret = 1;
+        if (want_flush_seq > 0 && ci->i_flushing_caps)
+                ret1 = ci->i_cap_flush_seq >= want_flush_seq;
+
+        if (want_snap_seq > 0 && !list_empty(&ci->i_cap_snaps)) {
+                struct ceph_cap_snap *capsnap =
+                        list_first_entry(&ci->i_cap_snaps,
+                                         struct ceph_cap_snap, ci_item);
+                ret2 = capsnap->follows >= want_snap_seq;
+        }
         spin_unlock(&ci->i_ceph_lock);
-        return ret;
+        return ret1 && ret2;
 }
 
 /*
@@ -1506,45 +1511,72 @@ static int check_cap_flush(struct inode *inode, u64 want_flush_seq)
  *
  * returns true if we've flushed through want_flush_seq
  */
-static void wait_caps_flush(struct ceph_mds_client *mdsc, u64 want_flush_seq)
+static void wait_caps_flush(struct ceph_mds_client *mdsc,
+                            u64 want_flush_seq, u64 want_snap_seq)
 {
         int mds;
 
         dout("check_cap_flush want %lld\n", want_flush_seq);
         mutex_lock(&mdsc->mutex);
-        for (mds = 0; mds < mdsc->max_sessions; mds++) {
+        for (mds = 0; mds < mdsc->max_sessions; ) {
                 struct ceph_mds_session *session = mdsc->sessions[mds];
-                struct inode *inode = NULL;
+                struct inode *inode1 = NULL, *inode2 = NULL;
 
-                if (!session)
+                if (!session) {
+                        mds++;
                         continue;
+                }
                 get_session(session);
                 mutex_unlock(&mdsc->mutex);
 
                 mutex_lock(&session->s_mutex);
                 if (!list_empty(&session->s_cap_flushing)) {
                         struct ceph_inode_info *ci =
-                                list_entry(session->s_cap_flushing.next,
-                                           struct ceph_inode_info,
-                                           i_flushing_item);
+                                list_first_entry(&session->s_cap_flushing,
+                                                 struct ceph_inode_info,
+                                                 i_flushing_item);
 
-                        if (!check_cap_flush(&ci->vfs_inode, want_flush_seq)) {
+                        if (!check_cap_flush(ci, want_flush_seq, 0)) {
                                 dout("check_cap_flush still flushing %p "
                                      "seq %lld <= %lld to mds%d\n",
                                      &ci->vfs_inode, ci->i_cap_flush_seq,
-                                     want_flush_seq, session->s_mds);
-                                inode = igrab(&ci->vfs_inode);
+                                     want_flush_seq, mds);
+                                inode1 = igrab(&ci->vfs_inode);
+                        }
+                }
+                if (!list_empty(&session->s_cap_snaps_flushing)) {
+                        struct ceph_cap_snap *capsnap =
+                                list_first_entry(&session->s_cap_snaps_flushing,
+                                                 struct ceph_cap_snap,
+                                                 flushing_item);
+                        struct ceph_inode_info *ci = capsnap->ci;
+                        if (!check_cap_flush(ci, 0, want_snap_seq)) {
+                                dout("check_cap_flush still flushing snap %p "
+                                     "follows %lld <= %lld to mds%d\n",
+                                     &ci->vfs_inode, capsnap->follows,
+                                     want_snap_seq, mds);
+                                inode2 = igrab(&ci->vfs_inode);
                         }
                 }
                 mutex_unlock(&session->s_mutex);
                 ceph_put_mds_session(session);
 
-                if (inode) {
+                if (inode1) {
                         wait_event(mdsc->cap_flushing_wq,
-                                   check_cap_flush(inode, want_flush_seq));
-                        iput(inode);
+                                   check_cap_flush(ceph_inode(inode1),
+                                                   want_flush_seq, 0));
+                        iput(inode1);
+                }
+                if (inode2) {
+                        wait_event(mdsc->cap_flushing_wq,
+                                   check_cap_flush(ceph_inode(inode2),
+                                                   0, want_snap_seq));
+                        iput(inode2);
                 }
 
+                if (!inode1 && !inode2)
+                        mds++;
+
                 mutex_lock(&mdsc->mutex);
         }
 
@@ -3391,6 +3423,7 @@ int ceph_mdsc_init(struct ceph_fs_client *fsc)
         atomic_set(&mdsc->num_sessions, 0);
         mdsc->max_sessions = 0;
         mdsc->stopping = 0;
+        mdsc->last_snap_seq = 0;
         init_rwsem(&mdsc->snap_rwsem);
         mdsc->snap_realms = RB_ROOT;
         INIT_LIST_HEAD(&mdsc->snap_empty);
@@ -3517,7 +3550,7 @@ restart:
 
 void ceph_mdsc_sync(struct ceph_mds_client *mdsc)
 {
-        u64 want_tid, want_flush;
+        u64 want_tid, want_flush, want_snap;
 
         if (mdsc->fsc->mount_state == CEPH_MOUNT_SHUTDOWN)
                 return;
@@ -3532,10 +3565,15 @@ void ceph_mdsc_sync(struct ceph_mds_client *mdsc)
         want_flush = mdsc->cap_flush_seq;
         spin_unlock(&mdsc->cap_dirty_lock);
 
-        dout("sync want tid %lld flush_seq %lld\n", want_tid, want_flush);
+        down_read(&mdsc->snap_rwsem);
+        want_snap = mdsc->last_snap_seq;
+        up_read(&mdsc->snap_rwsem);
+
+        dout("sync want tid %lld flush_seq %lld snap_seq %lld\n",
+             want_tid, want_flush, want_snap);
 
         wait_unsafe_requests(mdsc, want_tid);
-        wait_caps_flush(mdsc, want_flush);
+        wait_caps_flush(mdsc, want_flush, want_snap);
 }
 
 /*
diff --git a/fs/ceph/mds_client.h b/fs/ceph/mds_client.h
index d474141c034a..bf24d88cfeb2 100644
--- a/fs/ceph/mds_client.h
+++ b/fs/ceph/mds_client.h
@@ -290,6 +290,7 @@ struct ceph_mds_client {
          * references (implying they contain no inodes with caps) that
          * should be destroyed.
          */
+        u64                     last_snap_seq;
         struct rw_semaphore     snap_rwsem;
         struct rb_root          snap_realms;
         struct list_head        snap_empty;
diff --git a/fs/ceph/snap.c b/fs/ceph/snap.c
index ba708017d60b..233d906aec02 100644
--- a/fs/ceph/snap.c
+++ b/fs/ceph/snap.c
@@ -730,6 +730,8 @@ more:
 
                 /* queue realm for cap_snap creation */
                 list_add(&realm->dirty_item, &dirty_realms);
+                if (realm->seq > mdsc->last_snap_seq)
+                        mdsc->last_snap_seq = realm->seq;
 
                 invalidate = 1;
         } else if (!realm->cached_context) {