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From: Eric Sandeen <sandeen@sandeen.net>
To: xfs-oss <xfs@oss.sgi.com>
Cc: Ole Tange <tange@binf.ku.dk>
Subject: [PATCH V2] xfs_repair: skip freelist scan of corrupt agf in no-modify mode
Date: Sat, 02 Mar 2013 15:23:12 -0600	[thread overview]
Message-ID: <51326DC0.8030403@sandeen.net> (raw)
In-Reply-To: <51313DE8.5080104@sandeen.net>

In xfs_repair's 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.

Reported-by: Ole Tange <tange@binf.ku.dk>
Signed-off-by: Eric Sandeen <sandeen@redhat.com>
---

V2: Remove dumb mistakes :/

diff --git a/repair/scan.c b/repair/scan.c
index 5345094..1d39bdc 100644
--- a/repair/scan.c
+++ b/repair/scan.c
@@ -1066,6 +1066,18 @@ scan_freelist(
 		return;
 	}
 	agfl = XFS_BUF_TO_AGFL(agflbuf);
+
+	if (no_modify) {
+		/* agf values not fixed in verify_set_agf, so recheck */
+		if (be32_to_cpu(agf->agf_flfirst) >= XFS_AGFL_SIZE(mp) ||
+		    be32_to_cpu(agf->agf_fllast) >= XFS_AGFL_SIZE(mp)) {
+			do_warn(_("agf %d freelist blocks bad, skipping "
+				  "freelist scan\n"), i);
+			return;
+		}
+	} else /* should have been fixed in verify_set_agf() */
+		ASSERT(0);
+
 	i = be32_to_cpu(agf->agf_flfirst);
 	count = 0;
 	for (;;) {


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  parent reply	other threads:[~2013-03-02 21:23 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-03-01 23:46 [PATCH] xfs_repair: skip freelist scan of dodgy agf in no-modify mode Eric Sandeen
2013-03-02  1:18 ` Dave Chinner
2013-03-02  1:22   ` Eric Sandeen
2013-03-02 21:23 ` Eric Sandeen [this message]
2013-03-03 23:36   ` [PATCH V2] xfs_repair: skip freelist scan of corrupt " 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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