Possibly bug in radix_tree_delete, and fix.

[Neil Brown]

Hi Nick,
 I believe there is a bug in radix_tree_delete introduced by:

http://www.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commitdiff;h=d5274261ea46f0aae93820fe36628249120d2f75

The nature of the bug is that if a tag is set on a node that is being
deleted, then that tag is unconditionally cleared in the parent of the
node, even if the deleted node has siblings with the tag still set.

I don't know what the large-scale consequences of this bug might be,
but I'm kinda hoping fixing it will fix a nasty NFS client related
oops we are seeing in radix_tree_tag_set ....

My suggested patch is below.

Please review, confirm, and Ack:

Thanks,
NeilBrown


Fix over-zealous clearing of tags in radix_tree_delete.

Signed-off-by: Neil Brown <neilb@xxxxxxx>

### Diffstat output
 ./lib/radix-tree.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff ./lib/radix-tree.c~current~ ./lib/radix-tree.c
--- ./lib/radix-tree.c~current~	2006-02-16 13:22:28.000000000 +1100
+++ ./lib/radix-tree.c	2006-02-16 13:23:19.000000000 +1100
@@ -755,7 +755,7 @@ void *radix_tree_delete(struct radix_tre
 	for (tag = 0; tag < RADIX_TREE_TAGS; tag++) {
 		if (tag_get(pathp->node, tag, pathp->offset)) {
 			tag_clear(pathp->node, tag, pathp->offset);
-			tags[tag] = 0;
+			tags[tag] = any_tag_set(pathp->node, tag);
 			nr_cleared_tags++;
 		} else
 			tags[tag] = 1;
-
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