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rbd: split rbd_dev_spec_update() into two functions 

rbd_dev_spec_update() has two modes of operation, with nothing in
common between them.  Split it into two functions, one for each mode
and make our expectations more clear.

Signed-off-by: Ilya Dryomov <ilya.dryomov@inktank.com>
Reviewed-by: Alex Elder <elder@linaro.org>
This commit is contained in:
Ilya Dryomov 2014-07-23 17:11:20 +04:00
parent 7626eb7d82
commit 0407759971
1 changed files with 49 additions and 32 deletions
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81
drivers/block/rbd.c
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@ -3798,6 +3798,9 @@ static struct rbd_spec *rbd_spec_alloc(void)
spec = kzalloc(sizeof (*spec), GFP_KERNEL);
if (!spec)
return NULL;
spec->pool_id = CEPH_NOPOOL;
spec->snap_id = CEPH_NOSNAP;
kref_init(&spec->kref);
return spec;
@ -4257,18 +4260,38 @@ static u64 rbd_snap_id_by_name(struct rbd_device *rbd_dev, const char *name)
}
/*
* When an rbd image has a parent image, it is identified by the
* pool, image, and snapshot ids (not names). This function fills
* in the names for those ids. (It's OK if we can't figure out the
* name for an image id, but the pool and snapshot ids should always
* exist and have names.) All names in an rbd spec are dynamically
* allocated.
*
* When an image being mapped (not a parent) is probed, we have the
* pool name and pool id, image name and image id, and the snapshot
* name. The only thing we're missing is the snapshot id.
* An image being mapped will have everything but the snap id.
*/
static int rbd_dev_spec_update(struct rbd_device *rbd_dev)
static int rbd_spec_fill_snap_id(struct rbd_device *rbd_dev)
{
struct rbd_spec *spec = rbd_dev->spec;
rbd_assert(spec->pool_id != CEPH_NOPOOL && spec->pool_name);
rbd_assert(spec->image_id && spec->image_name);
rbd_assert(spec->snap_name);
if (strcmp(spec->snap_name, RBD_SNAP_HEAD_NAME)) {
u64 snap_id;
snap_id = rbd_snap_id_by_name(rbd_dev, spec->snap_name);
if (snap_id == CEPH_NOSNAP)
return -ENOENT;
spec->snap_id = snap_id;
} else {
spec->snap_id = CEPH_NOSNAP;
}
return 0;
}
/*
* A parent image will have all ids but none of the names.
*
* All names in an rbd spec are dynamically allocated. It's OK if we
* can't figure out the name for an image id.
*/
static int rbd_spec_fill_names(struct rbd_device *rbd_dev)
{
struct ceph_osd_client *osdc = &rbd_dev->rbd_client->client->osdc;
struct rbd_spec *spec = rbd_dev->spec;
@ -4277,24 +4300,9 @@ static int rbd_dev_spec_update(struct rbd_device *rbd_dev)
const char *snap_name;
int ret;
/*
* An image being mapped will have the pool name (etc.), but
* we need to look up the snapshot id.
*/
if (spec->pool_name) {
if (strcmp(spec->snap_name, RBD_SNAP_HEAD_NAME)) {
u64 snap_id;
snap_id = rbd_snap_id_by_name(rbd_dev, spec->snap_name);
if (snap_id == CEPH_NOSNAP)
return -ENOENT;
spec->snap_id = snap_id;
} else {
spec->snap_id = CEPH_NOSNAP;
}
return 0;
}
rbd_assert(spec->pool_id != CEPH_NOPOOL);
rbd_assert(spec->image_id);
rbd_assert(spec->snap_id != CEPH_NOSNAP);
/* Get the pool name; we have to make our own copy of this */
@ -4313,7 +4321,7 @@ static int rbd_dev_spec_update(struct rbd_device *rbd_dev)
if (!image_name)
rbd_warn(rbd_dev, "unable to get image name");
/* Look up the snapshot name, and make a copy */
/* Fetch the snapshot name */
snap_name = rbd_snap_name(rbd_dev, spec->snap_id);
if (IS_ERR(snap_name)) {
@ -4326,10 +4334,10 @@ static int rbd_dev_spec_update(struct rbd_device *rbd_dev)
spec->snap_name = snap_name;
return 0;
out_err:
kfree(image_name);
kfree(pool_name);
return ret;
}
@ -5158,7 +5166,16 @@ static int rbd_dev_image_probe(struct rbd_device *rbd_dev, bool mapping)
if (ret)
goto err_out_watch;
ret = rbd_dev_spec_update(rbd_dev);
/*
* If this image is the one being mapped, we have pool name and
* id, image name and id, and snap name - need to fill snap id.
* Otherwise this is a parent image, identified by pool, image
* and snap ids - need to fill in names for those ids.
*/
if (mapping)
ret = rbd_spec_fill_snap_id(rbd_dev);
else
ret = rbd_spec_fill_names(rbd_dev);
if (ret)
goto err_out_probe;