From: Theodore Ts'o Subject: [PATCH 2.6.33.y 14/40] ext4: Fix possible lost inode write in no journal mode Date: Tue, 1 Jun 2010 08:03:01 -0400 Message-ID: <1275393807-14369-14-git-send-email-tytso@mit.edu> References: <1275393807-14369-1-git-send-email-tytso@mit.edu> Cc: Ext4 Developers List , Curt Wohlgemuth , "Theodore Ts'o" To: stable@vger.kernel.org Return-path: Received: from THUNK.ORG ([69.25.196.29]:47395 "EHLO thunker.thunk.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756126Ab0FAMDt (ORCPT ); Tue, 1 Jun 2010 08:03:49 -0400 In-Reply-To: <1275393807-14369-1-git-send-email-tytso@mit.edu> Sender: linux-ext4-owner@vger.kernel.org List-ID: From: Curt Wohlgemuth commit 8b472d739b2ddd8ab7fb278874f696cd95b25a5e upstream (as of v2.6.34-rc6) In the no-journal case, ext4_write_inode() will fetch the bh and call sync_dirty_buffer() on it. However, if the bh has already been written and the bh reclaimed for some other purpose, AND if the inode is the only one in the inode table block in use, then ext4_get_inode_loc() will not read the inode table block from disk, but as an optimization, fill the block with zero's assuming that its caller will copy in the on-disk version of the inode. This is not done by ext4_write_inode(), so the contents of the inode can simply get lost. The fix is to use __ext4_get_inode_loc() with in_mem set to 0, instead of ext4_get_inode_loc(). Long term the API needs to be fixed so it's obvious why latter is not safe. Addresses-Google-Bug: #2526446 Signed-off-by: Curt Wohlgemuth Signed-off-by: "Theodore Ts'o" --- fs/ext4/inode.c | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-) diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index ff04c74..28152f8 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -5204,7 +5204,7 @@ int ext4_write_inode(struct inode *inode, int wait) } else { struct ext4_iloc iloc; - err = ext4_get_inode_loc(inode, &iloc); + err = __ext4_get_inode_loc(inode, &iloc, 0); if (err) return err; if (wait) -- 1.6.6.1.1.g974db.dirty