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Diffstat (limited to 'fs/ceph/snap.c')
-rw-r--r--fs/ceph/snap.c26
1 files changed, 25 insertions, 1 deletions
diff --git a/fs/ceph/snap.c b/fs/ceph/snap.c
index c1cc993225e3..f64576e72b79 100644
--- a/fs/ceph/snap.c
+++ b/fs/ceph/snap.c
@@ -288,6 +288,9 @@ static int cmpu64_rev(const void *a, const void *b)
return 0;
}
+
+static struct ceph_snap_context *empty_snapc;
+
/*
* build the snap context for a given realm.
*/
@@ -328,6 +331,12 @@ static int build_snap_context(struct ceph_snap_realm *realm)
return 0;
}
+ if (num == 0 && realm->seq == empty_snapc->seq) {
+ ceph_get_snap_context(empty_snapc);
+ snapc = empty_snapc;
+ goto done;
+ }
+
/* alloc new snap context */
err = -ENOMEM;
if (num > (SIZE_MAX - sizeof(*snapc)) / sizeof(u64))
@@ -365,6 +374,7 @@ static int build_snap_context(struct ceph_snap_realm *realm)
realm->ino, realm, snapc, snapc->seq,
(unsigned int) snapc->num_snaps);
+done:
ceph_put_snap_context(realm->cached_context);
realm->cached_context = snapc;
return 0;
@@ -465,6 +475,9 @@ void ceph_queue_cap_snap(struct ceph_inode_info *ci)
cap_snap. lucky us. */
dout("queue_cap_snap %p already pending\n", inode);
kfree(capsnap);
+ } else if (ci->i_snap_realm->cached_context == empty_snapc) {
+ dout("queue_cap_snap %p empty snapc\n", inode);
+ kfree(capsnap);
} else if (dirty & (CEPH_CAP_AUTH_EXCL|CEPH_CAP_XATTR_EXCL|
CEPH_CAP_FILE_EXCL|CEPH_CAP_FILE_WR)) {
struct ceph_snap_context *snapc = ci->i_head_snapc;
@@ -925,5 +938,16 @@ out:
return;
}
+int __init ceph_snap_init(void)
+{
+ empty_snapc = ceph_create_snap_context(0, GFP_NOFS);
+ if (!empty_snapc)
+ return -ENOMEM;
+ empty_snapc->seq = 1;
+ return 0;
+}
-
+void ceph_snap_exit(void)
+{
+ ceph_put_snap_context(empty_snapc);
+}