[DO NOT MERGE] ceph: dump info about cap flushes when we're waiting too long for...

We've had some cases of hung umounts in teuthology testing. It looks
like client is waiting for cap flushes to complete, but they aren't.

Add a field to the inode to track the highest cap flush tid seen for
that inode. Also, add a backpointer to the inode to the ceph_cap_flush
struct.

Change wait_caps_flush to wait 60s, and then dump info about the
condition of the list.

Also, print pr_info messages if we end up dropping a FLUSH_ACK for an
inode onto the floor, or if we get a message on an unregistered
session.

Reported-by: Patrick Donnelly <pdonnell@redhat.com>
URL: https://tracker.ceph.com/issues/51279
Signed-off-by: Jeff Layton <jlayton@kernel.org>

diff --git a/fs/ceph/caps.c b/fs/ceph/caps.c
index 5c14ef04e474247e3d98fbdacfef017c5950d217..b8d0e7610e1033c929b8223308249da61994314c 100644 (file)
--- a/fs/ceph/caps.c
+++ b/fs/ceph/caps.c
@@ -1826,6 +1826,7 @@ static u64 __mark_caps_flushing(struct inode *inode,
        swap(cf, ci->i_prealloc_cap_flush);
        cf->caps = flushing;
        cf->wake = wake;
+       cf->ci = ci;
 
        spin_lock(&mdsc->cap_dirty_lock);
        list_del_init(&ci->i_dirty_item);
@@ -3627,6 +3628,10 @@ static void handle_cap_flush_ack(struct inode *inode, u64 flush_tid,
        bool wake_ci = false;
        bool wake_mdsc = false;
 
+       /* track latest cap flush ack seen for this inode */
+       if (flush_tid > ci->i_last_cap_flush_ack)
+               ci->i_last_cap_flush_ack = flush_tid;
+
        list_for_each_entry_safe(cf, tmp_cf, &ci->i_cap_flush_list, i_list) {
                /* Is this the one that was flushed? */
                if (cf->tid == flush_tid)
@@ -4182,7 +4187,11 @@ void ceph_handle_caps(struct ceph_mds_session *session,
             (unsigned)seq);
 
        if (!inode) {
-               dout(" i don't have ino %llx\n", vino.ino);
+               if (op == CEPH_CAP_OP_FLUSH_ACK)
+                       pr_info("%s: can't find ino %llx:%llx for flush_ack!\n",
+                               __func__, vino.snap, vino.ino);
+               else
+                       dout(" i don't have ino %llx\n", vino.ino);
 
                if (op == CEPH_CAP_OP_IMPORT) {
                        cap = ceph_get_cap(mdsc, NULL);
@@ -4236,10 +4245,14 @@ void ceph_handle_caps(struct ceph_mds_session *session,
        spin_lock(&ci->i_ceph_lock);
        cap = __get_cap_for_mds(ceph_inode(inode), session->s_mds);
        if (!cap) {
-               dout(" no cap on %p ino %llx.%llx from mds%d\n",
+               dout(" no cap on %p ino %llx:%llx from mds%d\n",
                     inode, ceph_ino(inode), ceph_snap(inode),
                     session->s_mds);
                spin_unlock(&ci->i_ceph_lock);
+               if (op == CEPH_CAP_OP_FLUSH_ACK)
+                       pr_info("%s: no cap on %p ino %llx:%llx from mds%d for flush_ack!\n",
+                               __func__, inode, ceph_ino(inode),
+                               ceph_snap(inode), session->s_mds);
                goto flush_cap_releases;
        }
 

diff --git a/fs/ceph/inode.c b/fs/ceph/inode.c
index 63113e2a4890763e255048c31a0b228cdba13a22..3c7554d97093a4c2aa0234cc7e72cbaa96ca35a7 100644 (file)
--- a/fs/ceph/inode.c
+++ b/fs/ceph/inode.c
@@ -508,6 +508,7 @@ struct inode *ceph_alloc_inode(struct super_block *sb)
        INIT_LIST_HEAD(&ci->i_cap_snaps);
        ci->i_head_snapc = NULL;
        ci->i_snap_caps = 0;
+       ci->i_last_cap_flush_ack = 0;
 
        ci->i_last_rd = ci->i_last_wr = jiffies - 3600 * HZ;
        for (i = 0; i < CEPH_FILE_MODE_BITS; i++)

diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c
index 00c3de177dd66f5eb90451558fcfbf9e7a67a240..459c6f23915f3a0472e5bf359c6090152a3947cb 100644 (file)
--- a/fs/ceph/mds_client.c
+++ b/fs/ceph/mds_client.c
@@ -1991,6 +1991,24 @@ static int check_caps_flush(struct ceph_mds_client *mdsc,
        return ret;
 }
 
+static void dump_cap_flushes(struct ceph_mds_client *mdsc, u64 want_tid)
+{
+       struct ceph_cap_flush *cf;
+
+       pr_info("%s: still waiting for cap flushes through %llu:\n",
+               __func__, want_tid);
+       spin_lock(&mdsc->cap_dirty_lock);
+       list_for_each_entry(cf, &mdsc->cap_flush_list, g_list) {
+               if (cf->tid > want_tid)
+                       break;
+               pr_info("%llx:%llx %s %llu %llu %d\n",
+                       ceph_vinop(&cf->ci->vfs_inode),
+                       ceph_cap_string(cf->caps), cf->tid,
+                       cf->ci->i_last_cap_flush_ack, cf->wake);
+       }
+       spin_unlock(&mdsc->cap_dirty_lock);
+}
+
 /*
  * flush all dirty inode data to disk.
  *
@@ -1999,10 +2017,20 @@ static int check_caps_flush(struct ceph_mds_client *mdsc,
 static void wait_caps_flush(struct ceph_mds_client *mdsc,
                            u64 want_flush_tid)
 {
+       int i = 0;
+       long ret;
+
        dout("check_caps_flush want %llu\n", want_flush_tid);
 
-       wait_event(mdsc->cap_flushing_wq,
-                  check_caps_flush(mdsc, want_flush_tid));
+       do {
+               ret = wait_event_timeout(mdsc->cap_flushing_wq,
+                          check_caps_flush(mdsc, want_flush_tid), 60 * HZ);
+               if (ret == 0 && ++i < 5)
+                       dump_cap_flushes(mdsc, want_flush_tid);
+               else if (ret == 1)
+                       pr_info("%s: condition evaluated to true after timeout!\n",
+                                 __func__);
+       } while (ret == 0);
 
        dout("check_caps_flush ok, flushed thru %llu\n", want_flush_tid);
 }
@@ -5083,6 +5111,8 @@ static void mds_dispatch(struct ceph_connection *con, struct ceph_msg *msg)
 
        mutex_lock(&mdsc->mutex);
        if (__verify_registered_session(mdsc, s) < 0) {
+               pr_info("%s: dropping tid %llu from unregistered session %d\n",
+                       __func__, msg->hdr.tid, s->s_mds);
                mutex_unlock(&mdsc->mutex);
                goto out;
        }

diff --git a/fs/ceph/super.h b/fs/ceph/super.h
index 20ceab74e87178ef03acccad052d812fa7d147ce..73db7f6021f3e2facaf377d7ea537559b36d5e61 100644 (file)
--- a/fs/ceph/super.h
+++ b/fs/ceph/super.h
@@ -188,6 +188,7 @@ struct ceph_cap_flush {
        bool is_capsnap; /* true means capsnap */
        struct list_head g_list; // global
        struct list_head i_list; // per inode
+       struct ceph_inode_info *ci;
 };
 
 /*
@@ -392,6 +393,7 @@ struct ceph_inode_info {
        struct ceph_snap_context *i_head_snapc;  /* set if wr_buffer_head > 0 or
                                                    dirty|flushing caps */
        unsigned i_snap_caps;           /* cap bits for snapped files */
+       u64 i_last_cap_flush_ack;               /* latest cap flush_ack tid for this inode */
 
        unsigned long i_last_rd;
        unsigned long i_last_wr;