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authorAndreas Rohner <andreas.rohner@gmx.net>2014-01-14 17:56:36 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2014-01-15 14:19:42 +0700
commit70f2fe3a26248724d8a5019681a869abdaf3e89a (patch)
tree0aac8bf02f569804fdc96f2230b0f1906111fbd0
parenta6da83f98267bc8ee4e34aa899169991eb0ceb93 (diff)
downloadlinux-70f2fe3a26248724d8a5019681a869abdaf3e89a.tar.gz
nilfs2: fix segctor bug that causes file system corruption
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 <andreas.rohner@gmx.net> Reviewed-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp> Tested-by: Andreas Rohner <andreas.rohner@gmx.net> Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--fs/nilfs2/segment.c10
1 files changed, 6 insertions, 4 deletions
diff --git a/fs/nilfs2/segment.c b/fs/nilfs2/segment.c
index 9f6b486b6c0..a1a191634ab 100644
--- a/fs/nilfs2/segment.c
+++ b/fs/nilfs2/segment.c
@@ -1440,17 +1440,19 @@ static int nilfs_segctor_collect(struct nilfs_sc_info *sci,
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;
}