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rbd: refactor rbd_dev_probe_update_spec()

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Fairly straightforward refactoring of rbd_dev_probe_update_spec().
The name is changed to rbd_dev_spec_update().

Rearrange it so nothing gets assigned to the spec until all of the
names have been successfully acquired.

Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
This commit is contained in:
Alex Elder 2013-04-26 09:43:48 -05:00 committed by Sage Weil
parent 71f293e26e
commit 2e9f7f1c0d
1 changed files with 44 additions and 39 deletions
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83
drivers/block/rbd.c
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@ -3774,83 +3774,88 @@ out:
} }
/* /*
* When a parent image gets probed, we only have the pool, image, * When an rbd image has a parent image, it is identified by the
* and snapshot ids but not the names of any of them. This call * pool, image, and snapshot ids (not names). This function fills
* is made later to fill in those names. It has to be done after * in the names for those ids. (It's OK if we can't figure out the
* rbd_dev_snaps_update() has completed because some of the * name for an image id, but the pool and snapshot ids should always
* information (in particular, snapshot name) is not available * exist and have names.) All names in an rbd spec are dynamically
* until then. * allocated.
* *
* When an image being mapped (not a parent) is probed, we have the * 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 * pool name and pool id, image name and image id, and the snapshot
* name. The only thing we're missing is the snapshot id. * name. The only thing we're missing is the snapshot id.
*
* The set of snapshots for an image is not known until they have
* been read by rbd_dev_snaps_update(), so we can't completely fill
* in this information until after that has been called.
*/ */
static int rbd_dev_probe_update_spec(struct rbd_device *rbd_dev) static int rbd_dev_spec_update(struct rbd_device *rbd_dev)
{ {
struct ceph_osd_client *osdc; struct ceph_osd_client *osdc = &rbd_dev->rbd_client->client->osdc;
const char *name; struct rbd_spec *spec = rbd_dev->spec;
void *reply_buf = NULL; const char *pool_name;
const char *image_name;
const char *snap_name;
int ret; int ret;
/* /*
* An image being mapped will have the pool name (etc.), but * An image being mapped will have the pool name (etc.), but
* we need to look up the snapshot id. * we need to look up the snapshot id.
*/ */
if (rbd_dev->spec->pool_name) { if (spec->pool_name) {
if (strcmp(rbd_dev->spec->snap_name, RBD_SNAP_HEAD_NAME)) { if (strcmp(spec->snap_name, RBD_SNAP_HEAD_NAME)) {
struct rbd_snap *snap; struct rbd_snap *snap;
snap = snap_by_name(rbd_dev, rbd_dev->spec->snap_name); snap = snap_by_name(rbd_dev, spec->snap_name);
if (!snap) if (!snap)
return -ENOENT; return -ENOENT;
rbd_dev->spec->snap_id = snap->id; spec->snap_id = snap->id;
} else { } else {
rbd_dev->spec->snap_id = CEPH_NOSNAP; spec->snap_id = CEPH_NOSNAP;
} }
return 0; return 0;
} }
/* Look up the pool name */ /* Get the pool name; we have to make our own copy of this */
osdc = &rbd_dev->rbd_client->client->osdc; pool_name = ceph_pg_pool_name_by_id(osdc->osdmap, spec->pool_id);
name = ceph_pg_pool_name_by_id(osdc->osdmap, rbd_dev->spec->pool_id); if (!pool_name) {
if (!name) { rbd_warn(rbd_dev, "no pool with id %llu", spec->pool_id);
rbd_warn(rbd_dev, "there is no pool with id %llu",
rbd_dev->spec->pool_id); /* Really a BUG() */
return -EIO; return -EIO;
} }
pool_name = kstrdup(pool_name, GFP_KERNEL);
rbd_dev->spec->pool_name = kstrdup(name, GFP_KERNEL); if (!pool_name)
if (!rbd_dev->spec->pool_name)
return -ENOMEM; return -ENOMEM;
/* Fetch the image name; tolerate failure here */ /* Fetch the image name; tolerate failure here */
name = rbd_dev_image_name(rbd_dev); image_name = rbd_dev_image_name(rbd_dev);
if (name) if (!image_name)
rbd_dev->spec->image_name = (char *)name;
else
rbd_warn(rbd_dev, "unable to get image name"); rbd_warn(rbd_dev, "unable to get image name");
/* Look up the snapshot name. */ /* Look up the snapshot name, and make a copy */
name = rbd_snap_name(rbd_dev, rbd_dev->spec->snap_id); snap_name = rbd_snap_name(rbd_dev, spec->snap_id);
if (!name) { if (!snap_name) {
rbd_warn(rbd_dev, "no snapshot with id %llu", rbd_warn(rbd_dev, "no snapshot with id %llu", spec->snap_id);
rbd_dev->spec->snap_id); /* Really a BUG() */
ret = -EIO; ret = -EIO;
goto out_err; goto out_err;
} }
rbd_dev->spec->snap_name = kstrdup(name, GFP_KERNEL); snap_name = kstrdup(snap_name, GFP_KERNEL);
if(!rbd_dev->spec->snap_name) if (!snap_name) {
ret = -ENOMEM;
goto out_err; goto out_err;
}
spec->pool_name = pool_name;
spec->image_name = image_name;
spec->snap_name = snap_name;
return 0; return 0;
out_err: out_err:
kfree(reply_buf); kfree(image_name);
kfree(rbd_dev->spec->pool_name); kfree(pool_name);
rbd_dev->spec->pool_name = NULL;
return ret; return ret;
} }
@ -4710,7 +4715,7 @@ static int rbd_dev_probe_finish(struct rbd_device *rbd_dev)
if (ret) if (ret)
return ret; return ret;
ret = rbd_dev_probe_update_spec(rbd_dev); ret = rbd_dev_spec_update(rbd_dev);
if (ret) if (ret)
goto err_out_snaps; goto err_out_snaps;