Reviewed-by: Josh Durgin <josh.durgin@xxxxxxxxxxx>
On 04/26/2013 05:06 AM, Alex Elder wrote:
When the snapshot context for an rbd device gets updated (or the
initial one is recorded) a a list of snapshot structures is created
to represent them, one entry per snapshot. Each entry includes a
dynamically-allocated copy of the snapshot name.
Currently the name is allocated in rbd_snap_create(), as a duplicate
of the passed-in name.
For format 1 images, the snapshot name provided is just a pointer to
an existing name. But for format 2 images, the passed-in name is
already dynamically allocated, and in the the process of duplicating
it here we are leaking the passed-in name.
Fix this by dynamically allocating the name for format 1 snapshots
also, and then stop allocating a duplicate in rbd_snap_create().
Change rbd_dev_v1_snap_info() so none of its parameters is
side-effected unless it's going to return success.
This is part of:
http://tracker.ceph.com/issues/4803
Signed-off-by: Alex Elder <elder@xxxxxxxxxxx>
---
drivers/block/rbd.c | 27 ++++++++++++---------------
1 file changed, 12 insertions(+), 15 deletions(-)
diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
index 916741b..2b5ba50 100644
--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -3427,30 +3427,23 @@ static struct rbd_snap *rbd_snap_create(struct
rbd_device *rbd_dev,
u64 snap_features)
{
struct rbd_snap *snap;
- int ret;
snap = kzalloc(sizeof (*snap), GFP_KERNEL);
if (!snap)
return ERR_PTR(-ENOMEM);
- ret = -ENOMEM;
- snap->name = kstrdup(snap_name, GFP_KERNEL);
- if (!snap->name)
- goto err;
-
+ snap->name = snap_name;
snap->id = snap_id;
snap->size = snap_size;
snap->features = snap_features;
return snap;
-
-err:
- kfree(snap->name);
- kfree(snap);
-
- return ERR_PTR(ret);
}
+/*
+ * Returns a dynamically-allocated snapshot name if successful, or a
+ * pointer-coded error otherwise.
+ */
static char *rbd_dev_v1_snap_info(struct rbd_device *rbd_dev, u32 which,
u64 *snap_size, u64 *snap_features)
{
@@ -3458,15 +3451,19 @@ static char *rbd_dev_v1_snap_info(struct
rbd_device *rbd_dev, u32 which,
rbd_assert(which < rbd_dev->header.snapc->num_snaps);
- *snap_size = rbd_dev->header.snap_sizes[which];
- *snap_features = 0; /* No features for v1 */
-
/* Skip over names until we find the one we are looking for */
snap_name = rbd_dev->header.snap_names;
while (which--)
snap_name += strlen(snap_name) + 1;
+ snap_name = kstrdup(snap_name, GFP_KERNEL);
+ if (!snap_name);
+ return ERR_PTR(-ENOMEM);
+
+ *snap_size = rbd_dev->header.snap_sizes[which];
+ *snap_features = 0; /* No features for v1 */
+
return snap_name;
}
--
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