Patch "xfs: fix remote symlinks on V5/CRC filesystems" has been added to the 4.1-stable tree

Patch "xfs: fix remote symlinks on V5/CRC filesystems" has been added to the 4.1-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    xfs: fix remote symlinks on V5/CRC filesystems

to the 4.1-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     xfs-fix-remote-symlinks-on-v5-crc-filesystems.patch
and it can be found in the queue-4.1 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 2ac56d3d4bd625450a54d4c3f9292d58f6b88232 Mon Sep 17 00:00:00 2001
From: Eric Sandeen <sandeen@redhat.com>
Date: Mon, 22 Jun 2015 09:42:48 +1000
Subject: xfs: fix remote symlinks on V5/CRC filesystems

From: Eric Sandeen <sandeen@redhat.com>

commit 2ac56d3d4bd625450a54d4c3f9292d58f6b88232 upstream.

If we create a CRC filesystem, mount it, and create a symlink with
a path long enough that it can't live in the inode, we get a very
strange result upon remount:

# ls -l mnt
total 4
lrwxrwxrwx. 1 root root 929 Jun 15 16:58 link -> XSLM

XSLM is the V5 symlink block header magic (which happens to be
followed by a NUL, so the string looks terminated).

xfs_readlink_bmap() advanced cur_chunk by the size of the header
for CRC filesystems, but never actually used that pointer; it
kept reading from bp->b_addr, which is the start of the block,
rather than the start of the symlink data after the header.

Looks like this problem goes back to v3.10.

Fixing this gets us reading the proper link target, again.

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 fs/xfs/xfs_symlink.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/fs/xfs/xfs_symlink.c
+++ b/fs/xfs/xfs_symlink.c
@@ -104,7 +104,7 @@ xfs_readlink_bmap(
 			cur_chunk += sizeof(struct xfs_dsymlink_hdr);
 		}
 
-		memcpy(link + offset, bp->b_addr, byte_cnt);
+		memcpy(link + offset, cur_chunk, byte_cnt);
 
 		pathlen -= byte_cnt;
 		offset += byte_cnt;


Patches currently in stable-queue which might be from sandeen@redhat.com are

queue-4.1/xfs-fix-remote-symlinks-on-v5-crc-filesystems.patch