From: Eric Sandeen <sandeen@sandeen.net>
To: xfs-oss <xfs@oss.sgi.com>
Cc: Ole Tange <tange@binf.ku.dk>
Subject: [PATCH] xfs_repair: skip freelist scan of dodgy agf in no-modify mode
Date: Fri, 01 Mar 2013 17:46:48 -0600 [thread overview]
Message-ID: <51313DE8.5080104@sandeen.net> (raw)
In no-modify mode (-n), verify_set_agf doesn't fix up bad
freelist blocks that it finds. When we get to scan_freelist,
this can wreak havoc if, for example, first > last and the loop
never exits; we index agfl->agfl_bno[i] off into the weeds.
To fix this, re-check the values in no-modify mode, and if
they're off, warn about it and skip the scan.
In addition, add a check to verify_set_agf() to ensure that
first <= last.
Reported-by: Ole Tange <tange@binf.ku.dk>
Signed-off-by: Eric Sandeen <sandeen@redhat.com>
---
diff --git a/repair/agheader.c b/repair/agheader.c
index 769022d..68789fe 100644
--- a/repair/agheader.c
+++ b/repair/agheader.c
@@ -86,6 +86,14 @@ verify_set_agf(xfs_mount_t *mp, xfs_agf_t *agf, xfs_agnumber_t i)
* check first/last AGF fields. if need be, lose the free
* space in the AGFL, we'll reclaim it later.
*/
+ if (be32_to_cpu(agf->agf_flfirst) > be32_to_cpu(agf->agf_fllast)) {
+ do_warn(_("flfirst %d in agf %d > fllast %d\n"),
+ be32_to_cpu(agf->agf_flfirst),
+ i, be32_to_cpu(agf->agf_fllast));
+ if (!no_modify)
+ agf->agf_fllast = agf->agf_flfirst = cpu_to_be32(0);
+ }
+
if (be32_to_cpu(agf->agf_flfirst) >= XFS_AGFL_SIZE(mp)) {
do_warn(_("flfirst %d in agf %d too large (max = %zu)\n"),
be32_to_cpu(agf->agf_flfirst),
diff --git a/repair/scan.c b/repair/scan.c
index 5345094..0f83fb4 100644
--- a/repair/scan.c
+++ b/repair/scan.c
@@ -1067,6 +1067,17 @@ scan_freelist(
}
agfl = XFS_BUF_TO_AGFL(agflbuf);
i = be32_to_cpu(agf->agf_flfirst);
+ if (no_modify) {
+ /* agf values not sanitized, so double check */
+ if (i >= XFS_AGFL_SIZE(mp) ||
+ be32_to_cpu(agf->agf_fllast) >= XFS_AGFL_SIZE(mp) ||
+ i > be32_to_cpu(agf->agf_fllast))
+ do_warn(_("agf %d freelist blocks bad, skipping scan\n"),
+ i);
+ return;
+ } else /* should have been fixed in verify_set_agf() */
+ ASSERT(0);
+
count = 0;
for (;;) {
bno = be32_to_cpu(agfl->agfl_bno[i]);
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next reply other threads:[~2013-03-01 23:46 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-03-01 23:46 Eric Sandeen [this message]
2013-03-02 1:18 ` [PATCH] xfs_repair: skip freelist scan of dodgy agf in no-modify mode Dave Chinner
2013-03-02 1:22 ` Eric Sandeen
2013-03-02 21:23 ` [PATCH V2] xfs_repair: skip freelist scan of corrupt " Eric Sandeen
2013-03-03 23:36 ` Dave Chinner
2013-03-08 20:31 ` Rich Johnston
2013-03-08 20:31 ` Eric Sandeen
2013-03-09 9:00 ` Dave Chinner
2013-03-11 12:20 ` Rich Johnston
2013-03-09 15:00 ` Eric Sandeen
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