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-rw-r--r--fs/ceph/snap.c54
1 files changed, 38 insertions, 16 deletions
diff --git a/fs/ceph/snap.c b/fs/ceph/snap.c
index ce35fbd4ba5d..a97e39f09ba6 100644
--- 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 */