Patch "xfs: handle error if xfs_btree_get_bufs fails" has been added to the 4.13-stable tree

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

xfs: handle error if xfs_btree_get_bufs fails

to the 4.13-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-handle-error-if-xfs_btree_get_bufs-fails.patch
and it can be found in the queue-4.13 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Eric Sandeen <[email protected]>
Date: Mon, 9 Oct 2017 21:08:06 -0700
Subject: xfs: handle error if xfs_btree_get_bufs fails

From: Eric Sandeen <[email protected]>

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.

---
 fs/xfs/libxfs/xfs_alloc.c |    8 ++++++++
 1 file changed, 8 insertions(+)

@@ -1584,6 +1584,10 @@ 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;

@@ -2141,6 +2145,10 @@ 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);
 	}
 

Patches currently in stable-queue which might be from [email protected] are

queue-4.13/xfs-handle-error-if-xfs_btree_get_bufs-fails.patch