Merge branches 'misc' and 'vdso' into for-next

[cascardo/linux.git] / fs / ceph / snap.c

diff --git a/fs/ceph/snap.c b/fs/ceph/snap.c
index ce35fbd..a97e39f 100644 (file)
--- a/fs/ceph/snap.c
+++ b/fs/ceph/snap.c
@@ -70,13 +70,11 @@ void ceph_get_snap_realm(struct ceph_mds_client *mdsc,
         * safe.  we do need to protect against concurrent empty list
         * additions, however.
         */
-       if (atomic_read(&realm->nref) == 0) {
+       if (atomic_inc_return(&realm->nref) == 1) {
                spin_lock(&mdsc->snap_empty_lock);
                list_del_init(&realm->empty_item);
                spin_unlock(&mdsc->snap_empty_lock);
        }
-
-       atomic_inc(&realm->nref);
 }
 
 static void __insert_snap_realm(struct rb_root *root,
@@ -116,7 +114,7 @@ static struct ceph_snap_realm *ceph_create_snap_realm(
        if (!realm)
                return ERR_PTR(-ENOMEM);
 
-       atomic_set(&realm->nref, 0);    /* tree does not take a ref */
+       atomic_set(&realm->nref, 1);    /* for caller */
        realm->ino = ino;
        INIT_LIST_HEAD(&realm->children);
        INIT_LIST_HEAD(&realm->child_item);
@@ -134,8 +132,8 @@ static struct ceph_snap_realm *ceph_create_snap_realm(
  *
  * caller must hold snap_rwsem for write.
  */
-struct ceph_snap_realm *ceph_lookup_snap_realm(struct ceph_mds_client *mdsc,
-                                              u64 ino)
+static struct ceph_snap_realm *__lookup_snap_realm(struct ceph_mds_client *mdsc,
+                                                  u64 ino)
 {
        struct rb_node *n = mdsc->snap_realms.rb_node;
        struct ceph_snap_realm *r;
@@ -154,6 +152,16 @@ struct ceph_snap_realm *ceph_lookup_snap_realm(struct ceph_mds_client *mdsc,
        return NULL;
 }
 
+struct ceph_snap_realm *ceph_lookup_snap_realm(struct ceph_mds_client *mdsc,
+                                              u64 ino)
+{
+       struct ceph_snap_realm *r;
+       r = __lookup_snap_realm(mdsc, ino);
+       if (r)
+               ceph_get_snap_realm(mdsc, r);
+       return r;
+}
+
 static void __put_snap_realm(struct ceph_mds_client *mdsc,
                             struct ceph_snap_realm *realm);
 
@@ -273,7 +281,6 @@ static int adjust_snap_realm_parent(struct ceph_mds_client *mdsc,
        }
        realm->parent_ino = parentino;
        realm->parent = parent;
-       ceph_get_snap_realm(mdsc, parent);
        list_add(&realm->child_item, &parent->children);
        return 1;
 }
@@ -631,12 +638,14 @@ static void queue_realm_cap_snaps(struct ceph_snap_realm *realm)
  * Caller must hold snap_rwsem for write.
  */
 int ceph_update_snap_trace(struct ceph_mds_client *mdsc,
-                          void *p, void *e, bool deletion)
+                          void *p, void *e, bool deletion,
+                          struct ceph_snap_realm **realm_ret)
 {
        struct ceph_mds_snap_realm *ri;    /* encoded */
        __le64 *snaps;                     /* encoded */
        __le64 *prior_parent_snaps;        /* encoded */
-       struct ceph_snap_realm *realm;
+       struct ceph_snap_realm *realm = NULL;
+       struct ceph_snap_realm *first_realm = NULL;
        int invalidate = 0;
        int err = -ENOMEM;
        LIST_HEAD(dirty_realms);
@@ -704,13 +713,18 @@ more:
        dout("done with %llx %p, invalidated=%d, %p %p\n", realm->ino,
             realm, invalidate, p, e);
 
-       if (p < e)
-               goto more;
-
        /* invalidate when we reach the _end_ (root) of the trace */
-       if (invalidate)
+       if (invalidate && p >= e)
                rebuild_snap_realms(realm);
 
+       if (!first_realm)
+               first_realm = realm;
+       else
+               ceph_put_snap_realm(mdsc, realm);
+
+       if (p < e)
+               goto more;
+
        /*
         * queue cap snaps _after_ we've built the new snap contexts,
         * so that i_head_snapc can be set appropriately.
@@ -721,12 +735,21 @@ more:
                queue_realm_cap_snaps(realm);
        }
 
+       if (realm_ret)
+               *realm_ret = first_realm;
+       else
+               ceph_put_snap_realm(mdsc, first_realm);
+
        __cleanup_empty_realms(mdsc);
        return 0;
 
 bad:
        err = -EINVAL;
 fail:
+       if (realm && !IS_ERR(realm))
+               ceph_put_snap_realm(mdsc, realm);
+       if (first_realm)
+               ceph_put_snap_realm(mdsc, first_realm);
        pr_err("update_snap_trace error %d\n", err);
        return err;
 }
@@ -844,7 +867,6 @@ void ceph_handle_snap(struct ceph_mds_client *mdsc,
                        if (IS_ERR(realm))
                                goto out;
                }
-               ceph_get_snap_realm(mdsc, realm);
 
                dout("splitting snap_realm %llx %p\n", realm->ino, realm);
                for (i = 0; i < num_split_inos; i++) {
@@ -905,7 +927,7 @@ skip_inode:
                /* we may have taken some of the old realm's children. */
                for (i = 0; i < num_split_realms; i++) {
                        struct ceph_snap_realm *child =
-                               ceph_lookup_snap_realm(mdsc,
+                               __lookup_snap_realm(mdsc,
                                           le64_to_cpu(split_realms[i]));
                        if (!child)
                                continue;
@@ -918,7 +940,7 @@ skip_inode:
         * snap, we can avoid queueing cap_snaps.
         */
        ceph_update_snap_trace(mdsc, p, e,
-                              op == CEPH_SNAP_OP_DESTROY);
+                              op == CEPH_SNAP_OP_DESTROY, NULL);
 
        if (op == CEPH_SNAP_OP_SPLIT)
                /* we took a reference when we created the realm, above */