tree ef2e2a707f1b5d5095c9e2e1e6d760d77ad2b31b
parent 8bdac5d1ed892da54b6b2069e50a47b3aa39460f
author Rob Landley <rob@landley.net> 1127450667 -0700
committer Linus Torvalds <torvalds@g5.osdl.org> 1127452657 -0700

[PATCH] Fix bd_claim() error code.

Problem: In some circumstances, bd_claim() is returning the wrong error
code.

If we try to swapon an unused block device that isn't swap formatted, we
get -EINVAL.  But if that same block device is already mounted, we instead
get -EBUSY, even though it still isn't a valid swap device.

This issue came up on the busybox list trying to get the error message
from "swapon -a" right.  If a swap device is already enabled, we get -EBUSY,
and we shouldn't report this as an error.  But we can't distinguish the two
-EBUSY conditions, which are very different errors.

In the code, bd_claim() returns either 0 or -EBUSY, but in this case busy
means "somebody other than sys_swapon has already claimed this", and
_that_ means this block device can't be a valid swap device.  So return
-EINVAL there.

Signed-off-by: Rob Landley <rob@landley.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>