From: Eric Sandeen <sandeen@sandeen.net>
Date: Wed, 29 Jul 2015 23:17:43 +0000 (+1000)
Subject: metadump: Zero out unused portion of the AGFL
X-Git-Tag: v3.2.4~8
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=18cdb6141c404f1a5b36a6447c4f0fb1f0e843dd;p=thirdparty%2Fxfsprogs-dev.git

metadump: Zero out unused portion of the AGFL

mkfs.xfs doesn't zero the AGFL, so if it hasn't been
entirely used, metadump can pick up stale data.  Zero
the unused parts.

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: Eric Sandeen <sandeen@sandeen.net>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
---

diff --git a/db/metadump.c b/db/metadump.c
index cd2edf056..8520f66c1 100644
--- a/db/metadump.c
+++ b/db/metadump.c
@@ -2099,6 +2099,23 @@ scan_ag(
 		if (stop_on_read_error)
 			goto pop_out;
 	} else {
+		if (agf && zero_stale_data) {
+			/* Zero out unused bits of agfl */
+			int i;
+			 __be32  *agfl_bno;
+
+			agfl_bno = XFS_BUF_TO_AGFL_BNO(mp, iocur_top->bp);
+			i = be32_to_cpu(agf->agf_fllast);
+
+			for (;;) {
+				if (++i == XFS_AGFL_SIZE(mp))
+					i = 0;
+				if (i == be32_to_cpu(agf->agf_flfirst))
+					break;
+				agfl_bno[i] = cpu_to_be32(NULLAGBLOCK);
+			}
+			iocur_top->need_crc = 1;
+		}
 		if (write_buf(iocur_top))
 			goto pop_out;
 	}