rbd: fix leak of format 2 snapshot names

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@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
This commit is contained in:
Alex Elder 2013-04-25 15:09:42 -05:00 committed by Sage Weil
parent 6087b51b9e
commit 6e584f5244

View File

@ -3427,46 +3427,44 @@ 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)
{
char *snap_name;
int i;
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--)
for (i = 0; i < which; i++)
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;
}