Commit da6a6b63 authored Sep 04, 2013 by Josh Durgin

rbd: fix error handling from rbd_snap_name()



rbd_snap_name() calls rbd_dev_v{1,2}_snap_name() depending on the
format of the image. The format 1 version returns NULL on error, which
is handled by the caller. The format 2 version returns an ERR_PTR,
which the caller of rbd_snap_name() does not expect.

Fortunately this is unlikely to occur in practice because
rbd_snap_id_by_name() is called before rbd_snap_name(). This would hit
similar errors to rbd_snap_name() (like the snapshot not existing) and
return early, so rbd_snap_name() would not hit an error unless the
snapshot was removed between the two calls or memory was exhausted.

Use an ERR_PTR in rbd_dev_v1_snap_name() so that the specific error
can be propagated, and it is consistent with rbd_dev_v2_snap_name().
Handle the ERR_PTR in the only rbd_snap_name() caller.

Suggested-by: Alex Elder <alex.elder@linaro.org>
Signed-off-by: Josh Durgin <josh.durgin@inktank.com>
Reviewed-by: Alex Elder <elder@linaro.org>

parent efadc98a

drivers/block/rbd.c

+6 −4

Original line number	Diff line number	Diff line
		@@ -927,12 +927,14 @@ static const char rbd_dev_v1_snap_name(struct rbd_device rbd_dev,
		u64 snap_id)
		{
		u32 which;
		const char *snap_name;

		which = rbd_dev_snap_index(rbd_dev, snap_id);
		if (which == BAD_SNAP_INDEX)
		return NULL;
		return ERR_PTR(-ENOENT);

		return _rbd_dev_v1_snap_name(rbd_dev, which);
		snap_name = _rbd_dev_v1_snap_name(rbd_dev, which);
		return snap_name ? snap_name : ERR_PTR(-ENOMEM);
		}

		static const char rbd_snap_name(struct rbd_device rbd_dev, u64 snap_id)
		@@ -4163,8 +4165,8 @@ static int rbd_dev_spec_update(struct rbd_device *rbd_dev)
		/* Look up the snapshot name, and make a copy */

		snap_name = rbd_snap_name(rbd_dev, spec->snap_id);
		if (!snap_name) {
		ret = -ENOMEM;
		if (IS_ERR(snap_name)) {
		ret = PTR_ERR(snap_name);
		goto out_err;
		}

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