btree: fix tree corruption in btree_get_prev()
authorRoland Dreier <roland@purestorage.com>
Thu, 7 Jun 2012 21:21:13 +0000 (14:21 -0700)
committerLinus Torvalds <torvalds@linux-foundation.org>
Thu, 7 Jun 2012 21:43:55 +0000 (14:43 -0700)
commitcbf8ae32f66a9ceb8907ad9e16663c2a29e48990
tree0e290072f6c077fffeafd74b540c7536e3aa9873
parent7d8a45695cc8f9fcdf4121fcbd897ecb63f758e4
btree: fix tree corruption in btree_get_prev()

The memory the parameter __key points to is used as an iterator in
btree_get_prev(), so if we save off a bkey() pointer in retry_key and
then assign that to __key, we'll end up corrupting the btree internals
when we do eg

longcpy(__key, bkey(geo, node, i), geo->keylen);

to return the key value.  What we should do instead is use longcpy() to
copy the key value that retry_key points to __key.

This can cause a btree to get corrupted by seemingly read-only
operations such as btree_for_each_safe.

[akpm@linux-foundation.org: avoid the double longcpy()]
Signed-off-by: Roland Dreier <roland@purestorage.com>
Acked-by: Joern Engel <joern@logfs.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
lib/btree.c