rbd: use a single value of snap_name to mean no snap
There's already a constant for this anyway.
Since rbd_header_set_snap() is only used to set the rbd device
snap_name field, just do that within that function rather than
having it take the snap_name as an argument.
Signed-off-by: Alex Elder <elder@dreamhost.com>
Signed-off-by: Sage Weil <sage@newdream.net>
v2: Changed interface rbd_header_set_snap() so it explicitly updates
the snap_name in the rbd_device. Also added a BUILD_BUG_ON()
to verify the size of the snap_name field is sufficient for
SNAP_HEAD_NAME.
diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
index dcdfe8d..d8d052d 100644
--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -553,20 +553,18 @@
return i;
}
-static int rbd_header_set_snap(struct rbd_device *dev,
- const char *snap_name,
- u64 *size)
+static int rbd_header_set_snap(struct rbd_device *dev, u64 *size)
{
struct rbd_image_header *header = &dev->header;
struct ceph_snap_context *snapc = header->snapc;
int ret = -ENOENT;
+ BUILD_BUG_ON(sizeof (dev->snap_name) < sizeof (RBD_SNAP_HEAD_NAME));
+
down_write(&header->snap_rwsem);
- if (!snap_name ||
- !*snap_name ||
- strcmp(snap_name, "-") == 0 ||
- strcmp(snap_name, RBD_SNAP_HEAD_NAME) == 0) {
+ if (!memcmp(dev->snap_name, RBD_SNAP_HEAD_NAME,
+ sizeof (RBD_SNAP_HEAD_NAME))) {
if (header->total_snaps)
snapc->seq = header->snap_seq;
else
@@ -576,7 +574,7 @@
if (size)
*size = header->image_size;
} else {
- ret = snap_by_name(header, snap_name, &snapc->seq, size);
+ ret = snap_by_name(header, dev->snap_name, &snapc->seq, size);
if (ret < 0)
goto done;
@@ -1729,7 +1727,7 @@
if (rc)
return rc;
- rc = rbd_header_set_snap(rbd_dev, rbd_dev->snap_name, &total_size);
+ rc = rbd_header_set_snap(rbd_dev, &total_size);
if (rc)
return rc;
@@ -2215,7 +2213,8 @@
}
if (rbd_dev->snap_name[0] == 0)
- rbd_dev->snap_name[0] = '-';
+ memcpy(rbd_dev->snap_name, RBD_SNAP_HEAD_NAME,
+ sizeof (RBD_SNAP_HEAD_NAME));
rbd_dev->obj_len = strlen(rbd_dev->obj);
snprintf(rbd_dev->obj_md_name, sizeof(rbd_dev->obj_md_name), "%s%s",