rbd: always set read-only flag in rbd_add()

Hold off setting the read-only flag in rbd_add() for an image being
mapped until we have successfully probed the image.  At that point
we know whether it's a snapshot mapping or not, so we can set the
read-only flag in that one place rather than doing so (for
snapshots) in rbd_dev_mapping_set().  To do this, pass a flag to the
image probe routine indicating whether we want a read-only mapping.

Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
This commit is contained in:
Alex Elder 2013-05-06 07:40:30 -05:00
parent 6d80b130d5
commit 51344a38ba

View File

@ -359,7 +359,7 @@ static ssize_t rbd_add(struct bus_type *bus, const char *buf,
size_t count);
static ssize_t rbd_remove(struct bus_type *bus, const char *buf,
size_t count);
static int rbd_dev_image_probe(struct rbd_device *rbd_dev);
static int rbd_dev_image_probe(struct rbd_device *rbd_dev, bool read_only);
static struct bus_attribute rbd_bus_attrs[] = {
__ATTR(add, S_IWUSR, NULL, rbd_add),
@ -951,11 +951,6 @@ static int rbd_dev_mapping_set(struct rbd_device *rbd_dev)
rbd_dev->mapping.size = size;
rbd_dev->mapping.features = features;
/* If we are mapping a snapshot it must be marked read-only */
if (snap_id != CEPH_NOSNAP)
rbd_dev->mapping.read_only = true;
return 0;
}
@ -963,7 +958,6 @@ static void rbd_dev_mapping_clear(struct rbd_device *rbd_dev)
{
rbd_dev->mapping.size = 0;
rbd_dev->mapping.features = 0;
rbd_dev->mapping.read_only = true;
}
static const char *rbd_segment_name(struct rbd_device *rbd_dev, u64 offset)
@ -4620,7 +4614,7 @@ static int rbd_dev_probe_parent(struct rbd_device *rbd_dev)
if (!parent)
goto out_err;
ret = rbd_dev_image_probe(parent);
ret = rbd_dev_image_probe(parent, true);
if (ret < 0)
goto out_err;
rbd_dev->parent = parent;
@ -4743,7 +4737,7 @@ static void rbd_dev_image_release(struct rbd_device *rbd_dev)
* device. For format 2 images this includes determining the image
* id.
*/
static int rbd_dev_image_probe(struct rbd_device *rbd_dev)
static int rbd_dev_image_probe(struct rbd_device *rbd_dev, bool read_only)
{
int ret;
int tmp;
@ -4778,6 +4772,12 @@ static int rbd_dev_image_probe(struct rbd_device *rbd_dev)
if (ret)
goto err_out_probe;
/* If we are mapping a snapshot it must be marked read-only */
if (rbd_dev->spec->snap_id != CEPH_NOSNAP)
read_only = true;
rbd_dev->mapping.read_only = read_only;
ret = rbd_dev_probe_parent(rbd_dev);
if (!ret)
return 0;
@ -4811,6 +4811,7 @@ static ssize_t rbd_add(struct bus_type *bus,
struct rbd_spec *spec = NULL;
struct rbd_client *rbdc;
struct ceph_osd_client *osdc;
bool read_only;
int rc = -ENOMEM;
if (!try_module_get(THIS_MODULE))
@ -4820,6 +4821,9 @@ static ssize_t rbd_add(struct bus_type *bus,
rc = rbd_add_parse_args(buf, &ceph_opts, &rbd_opts, &spec);
if (rc < 0)
goto err_out_module;
read_only = rbd_opts->read_only;
kfree(rbd_opts);
rbd_opts = NULL; /* done with this */
rbdc = rbd_get_client(ceph_opts);
if (IS_ERR(rbdc)) {
@ -4850,11 +4854,7 @@ static ssize_t rbd_add(struct bus_type *bus,
rbdc = NULL; /* rbd_dev now owns this */
spec = NULL; /* rbd_dev now owns this */
rbd_dev->mapping.read_only = rbd_opts->read_only;
kfree(rbd_opts);
rbd_opts = NULL; /* done with this */
rc = rbd_dev_image_probe(rbd_dev);
rc = rbd_dev_image_probe(rbd_dev, read_only);
if (rc < 0)
goto err_out_rbd_dev;