Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753207AbaAZDGu (ORCPT ); Sat, 25 Jan 2014 22:06:50 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:52714 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752465AbaAZDEf (ORCPT ); Sat, 25 Jan 2014 22:04:35 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Andreas Rohner , Ryusuke Konishi , Andrew Morton , Linus Torvalds Subject: [PATCH 3.4 07/12] nilfs2: fix segctor bug that causes file system corruption Date: Sat, 25 Jan 2014 19:05:10 -0800 Message-Id: <20140126030452.478733311@linuxfoundation.org> X-Mailer: git-send-email 1.9.rc0.19.gb594c97 In-Reply-To: <20140126030451.934281002@linuxfoundation.org> References: <20140126030451.934281002@linuxfoundation.org> User-Agent: quilt/0.60-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Andreas Rohner commit 70f2fe3a26248724d8a5019681a869abdaf3e89a upstream. There is a bug in the function nilfs_segctor_collect, which results in active data being written to a segment, that is marked as clean. It is possible, that this segment is selected for a later segment construction, whereby the old data is overwritten. The problem shows itself with the following kernel log message: nilfs_sufile_do_cancel_free: segment 6533 must be clean Usually a few hours later the file system gets corrupted: NILFS: bad btree node (blocknr=8748107): level = 0, flags = 0x0, nchildren = 0 NILFS error (device sdc1): nilfs_bmap_last_key: broken bmap (inode number=114660) The issue can be reproduced with a file system that is nearly full and with the cleaner running, while some IO intensive task is running. Although it is quite hard to reproduce. This is what happens: 1. The cleaner starts the segment construction 2. nilfs_segctor_collect is called 3. sc_stage is on NILFS_ST_SUFILE and segments are freed 4. sc_stage is on NILFS_ST_DAT current segment is full 5. nilfs_segctor_extend_segments is called, which allocates a new segment 6. The new segment is one of the segments freed in step 3 7. nilfs_sufile_cancel_freev is called and produces an error message 8. Loop around and the collection starts again 9. sc_stage is on NILFS_ST_SUFILE and segments are freed including the newly allocated segment, which will contain active data and can be allocated at a later time 10. A few hours later another segment construction allocates the segment and causes file system corruption This can be prevented by simply reordering the statements. If nilfs_sufile_cancel_freev is called before nilfs_segctor_extend_segments the freed segments are marked as dirty and cannot be allocated any more. Signed-off-by: Andreas Rohner Reviewed-by: Ryusuke Konishi Tested-by: Andreas Rohner Signed-off-by: Ryusuke Konishi Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- fs/nilfs2/segment.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) --- a/fs/nilfs2/segment.c +++ b/fs/nilfs2/segment.c @@ -1436,17 +1436,19 @@ static int nilfs_segctor_collect(struct nilfs_clear_logs(&sci->sc_segbufs); - err = nilfs_segctor_extend_segments(sci, nilfs, nadd); - if (unlikely(err)) - return err; - if (sci->sc_stage.flags & NILFS_CF_SUFREED) { err = nilfs_sufile_cancel_freev(nilfs->ns_sufile, sci->sc_freesegs, sci->sc_nfreesegs, NULL); WARN_ON(err); /* do not happen */ + sci->sc_stage.flags &= ~NILFS_CF_SUFREED; } + + err = nilfs_segctor_extend_segments(sci, nilfs, nadd); + if (unlikely(err)) + return err; + nadd = min_t(int, nadd << 1, SC_MAX_SEGDELTA); sci->sc_stage = prev_stage; } -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/