linux-kernel - [PATCH 4.9 182/206] xfs: always succeed when deduping zero bytes

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Tue, 10 Jan 2017 14:37:45 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        "Darrick J. Wong" <darrick.wong@...cle.com>,
        Dave Chinner <dchinner@...hat.com>,
        Dave Chinner <david@...morbit.com>,
        Christoph Hellwig <hch@....de>
Subject: [PATCH 4.9 182/206] xfs: always succeed when deduping zero bytes

4.9-stable review patch.  If anyone has any objections, please let me know.

------------------


From: "Darrick J. Wong" <darrick.wong@...cle.com>

commit fba3e594ef0ad911fa8f559732d588172f212d71 upstream.

It turns out that btrfs and xfs had differing interpretations of what
to do when the dedupe length is zero.  Change xfs to follow btrfs'
semantics so that the userland interface is consistent.

Signed-off-by: Darrick J. Wong <darrick.wong@...cle.com>
Reviewed-by: Dave Chinner <dchinner@...hat.com>
Signed-off-by: Dave Chinner <david@...morbit.com>
Cc: Christoph Hellwig <hch@....de>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 fs/xfs/xfs_reflink.c |    8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

--- a/fs/xfs/xfs_reflink.c
+++ b/fs/xfs/xfs_reflink.c
@@ -1345,8 +1345,14 @@ xfs_reflink_remap_range(
 		goto out_unlock;
 	}
 
-	if (len == 0)
+	/* Zero length dedupe exits immediately; reflink goes to EOF. */
+	if (len == 0) {
+		if (is_dedupe) {
+			ret = 0;
+			goto out_unlock;
+		}
 		len = isize - pos_in;
+	}
 
 	/* Ensure offsets don't wrap and the input is inside i_size */
 	if (pos_in + len < pos_in || pos_out + len < pos_out ||