From 3ccc3167b0e5d46ab3bf03e22fbdb7616ce038cd Mon Sep 17 00:00:00 2001 From: Duane Griffin Date: Fri, 25 Jul 2008 01:46:26 -0700 Subject: ext3: handle deleting corrupted indirect blocks While freeing indirect blocks we attach a journal head to the parent buffer head, free the blocks, then journal the parent. If the indirect block list is corrupted and points to the parent the journal head will be detached when the block is cleared, causing an OOPS. Check for that explicitly and handle it gracefully. This patch fixes the third case (image hdb.20000057.nullderef.gz) reported in http://bugzilla.kernel.org/show_bug.cgi?id=10882. Immediately above the change, in the ext3_free_data function, we call ext3_clear_blocks to clear the indirect blocks in this parent block. If one of those blocks happens to actually be the parent block it will clear b_private / BH_JBD. I did the check at the end rather than earlier as it seemed more elegant. I don't think there should be much practical difference, although it is possible the FS may not be quite so badly corrupted if we did it the other way (and didn't clear the block at all). To be honest, I'm not convinced there aren't other similar failure modes lurking in this code, although I couldn't find any with a quick review. [akpm@linux-foundation.org: fix printk warning] Signed-off-by: Duane Griffin Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/ext3/inode.c | 16 +++++++++++++++- 1 file changed, 15 insertions(+), 1 deletion(-) diff --git a/fs/ext3/inode.c b/fs/ext3/inode.c index 36f74f1..3bf07d7 100644 --- a/fs/ext3/inode.c +++ b/fs/ext3/inode.c @@ -2127,7 +2127,21 @@ static void ext3_free_data(handle_t *handle, struct inode *inode, if (this_bh) { BUFFER_TRACE(this_bh, "call ext3_journal_dirty_metadata"); - ext3_journal_dirty_metadata(handle, this_bh); + + /* + * The buffer head should have an attached journal head at this + * point. However, if the data is corrupted and an indirect + * block pointed to itself, it would have been detached when + * the block was cleared. Check for this instead of OOPSing. + */ + if (bh2jh(this_bh)) + ext3_journal_dirty_metadata(handle, this_bh); + else + ext3_error(inode->i_sb, "ext3_free_data", + "circular indirect block detected, " + "inode=%lu, block=%llu", + inode->i_ino, + (unsigned long long)this_bh->b_blocknr); } } -- cgit v1.1