Commit 67d73f41 authored Oct 09, 2017 by Eric Sandeen Committed by Greg Kroah-Hartman Oct 27, 2017

xfs: handle error if xfs_btree_get_bufs fails



commit 93e8befc17f6d6ea92b0aee3741ceac8bca4590f upstream.

Jason reported that a corrupted filesystem failed to replay
the log with a metadata block out of bounds warning:

XFS (dm-2): _xfs_buf_find: Block out of range: block 0x80270fff8, EOFS 0x9c40000

_xfs_buf_find() and xfs_btree_get_bufs() return NULL if
that happens, and then when xfs_alloc_fix_freelist() calls
xfs_trans_binval() on that NULL bp, we oops with:

BUG: unable to handle kernel NULL pointer dereference at 00000000000000f8

We don't handle _xfs_buf_find errors very well, every
caller higher up the stack gets to guess at why it failed.
But we should at least handle it somehow, so return
EFSCORRUPTED here.

Reported-by: Jason L Tibbitts III <tibbs@math.uh.edu>
Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent fee940a8

fs/xfs/libxfs/xfs_alloc.c

+8 −0

Original line number	Diff line number	Diff line
		@@ -1579,6 +1579,10 @@ xfs_alloc_ag_vextent_small(

		bp = xfs_btree_get_bufs(args->mp, args->tp,
		args->agno, fbno, 0);
		if (!bp) {
		error = -EFSCORRUPTED;
		goto error0;
		}
		xfs_trans_binval(args->tp, bp);
		}
		args->len = 1;
		@@ -2136,6 +2140,10 @@ xfs_alloc_fix_freelist(
		if (error)
		goto out_agbp_relse;
		bp = xfs_btree_get_bufs(mp, tp, args->agno, bno, 0);
		if (!bp) {
		error = -EFSCORRUPTED;
		goto out_agbp_relse;
		}
		xfs_trans_binval(tp, bp);
		}