2009-06-17 23:37:05

by Andrew Morton

[permalink] [raw]
Subject: [patch 029/133] ext3: fix chain verification in ext3_get_blocks()

From: Jan Kara <[email protected]>

Chain verification in ext3_get_blocks() has been hosed since it called
verify_chain(chain, NULL) which always returns success. As a result
readers could in theory race with truncate. On the other hand the race
probably cannot happen with the current locking scheme, since by the time
ext3_truncate() is called all the pages are already removed and hence
get_block() shouldn't be called on such pages...

Signed-off-by: Jan Kara <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

fs/ext3/inode.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff -puN fs/ext3/inode.c~ext3-fix-chain-verification-in-ext3_get_blocks fs/ext3/inode.c
--- a/fs/ext3/inode.c~ext3-fix-chain-verification-in-ext3_get_blocks
+++ a/fs/ext3/inode.c
@@ -820,7 +820,7 @@ int ext3_get_blocks_handle(handle_t *han
while (count < maxblocks && count <= blocks_to_boundary) {
ext3_fsblk_t blk;

- if (!verify_chain(chain, partial)) {
+ if (!verify_chain(chain, chain + depth - 1)) {
* Indirect block might be removed by
* truncate while we were reading it.