Patch "xfs: fix and streamline error handling in xfs_end_io" has been added to the 4.9-stable tree

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

xfs: fix and streamline error handling in xfs_end_io

to the 4.9-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-and-streamline-error-handling-in-xfs_end_io.patch
and it can be found in the queue-4.9 subdirectory.

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

From: Christoph Hellwig <[email protected]>
Date: Thu, 2 Mar 2017 15:02:51 -0800
Subject: xfs: fix and streamline error handling in xfs_end_io

From: Christoph Hellwig <[email protected]>

commit 787eb485509f9d58962bd8b4dbc6a5ac6e2034fe upstream.

There are two different cases of buffered I/O errors:

- first we can have an already shutdown fs. In that case we should skip any on-disk operations and just clean up the appen transaction if present and destroy the ioend
- a real I/O error. In that case we should cleanup any lingering COW blocks. This gets skipped in the current code and is fixed by this patch.

---
 fs/xfs/xfs_aops.c |   59 ++++++++++++++++++++++++------------------------------
 1 file changed, 27 insertions(+), 32 deletions(-)

@@ -279,54 +279,49 @@ xfs_end_io(
 	struct xfs_ioend	*ioend =
 		container_of(work, struct xfs_ioend, io_work);
 	struct xfs_inode	*ip = XFS_I(ioend->io_inode);
+	xfs_off_t		offset = ioend->io_offset;
+	size_t			size = ioend->io_size;
 	int			error = ioend->io_bio->bi_error;
 
 	/*
-	 * Set an error if the mount has shut down and proceed with end I/O
-	 * processing so it can perform whatever cleanups are necessary.
+	 * Just clean up the in-memory strutures if the fs has been shut down.
 	 */
-	if (XFS_FORCED_SHUTDOWN(ip->i_mount))
+	if (XFS_FORCED_SHUTDOWN(ip->i_mount)) {
 		error = -EIO;
+		goto done;
+	}
 
 	/*
-	 * For a CoW extent, we need to move the mapping from the CoW fork
-	 * to the data fork.  If instead an error happened, just dump the
-	 * new blocks.
+	 * Clean up any COW blocks on an I/O error.
 	 */
-	if (ioend->io_type == XFS_IO_COW) {
-		if (error)
-			goto done;
-		if (ioend->io_bio->bi_error) {
-			error = xfs_reflink_cancel_cow_range(ip,
-					ioend->io_offset, ioend->io_size, true);
-			goto done;
+	if (unlikely(error)) {
+		switch (ioend->io_type) {
+		case XFS_IO_COW:
+			xfs_reflink_cancel_cow_range(ip, offset, size, true);
+			break;
 		}
-		error = xfs_reflink_end_cow(ip, ioend->io_offset,
-				ioend->io_size);
-		if (error)
-			goto done;
+
+		goto done;
 	}
 
 	/*
-	 * For unwritten extents we need to issue transactions to convert a
-	 * range to normal written extens after the data I/O has finished.
-	 * Detecting and handling completion IO errors is done individually
-	 * for each case as different cleanup operations need to be performed
-	 * on error.
+	 * Success:  commit the COW or unwritten blocks if needed.
 	 */
-	if (ioend->io_type == XFS_IO_UNWRITTEN) {
-		if (error)
-			goto done;
-		error = xfs_iomap_write_unwritten(ip, ioend->io_offset,
-						  ioend->io_size);
-	} else if (ioend->io_append_trans) {
-		error = xfs_setfilesize_ioend(ioend, error);
-	} else {
-		ASSERT(!xfs_ioend_is_append(ioend) ||
-		       ioend->io_type == XFS_IO_COW);
+	switch (ioend->io_type) {
+	case XFS_IO_COW:
+		error = xfs_reflink_end_cow(ip, offset, size);
+		break;
+	case XFS_IO_UNWRITTEN:
+		error = xfs_iomap_write_unwritten(ip, offset, size);
+		break;
+	default:
+		ASSERT(!xfs_ioend_is_append(ioend) || ioend->io_append_trans);
+		break;
 	}
 
 done:
+	if (ioend->io_append_trans)
+		error = xfs_setfilesize_ioend(ioend, error);
 	xfs_destroy_ioend(ioend, error);
 }
 

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

queue-4.9/xfs-mark-speculative-prealloc-cow-fork-extents-unwritten.patch queue-4.9/xfs-fix-toctou-race-when-locking-an-inode-to-access-the-data-map.patch queue-4.9/xfs-use-iomap-new-flag-for-newly-allocated-delalloc-blocks.patch queue-4.9/xfs-reject-all-unaligned-direct-writes-to-reflinked-files.patch queue-4.9/xfs-allow-unwritten-extents-in-the-cow-fork.patch queue-4.9/xfs-tune-down-agno-asserts-in-the-bmap-code.patch queue-4.9/xfs-verify-free-block-header-fields.patch queue-4.9/xfs-check-for-obviously-bad-level-values-in-the-bmbt-root.patch queue-4.9/xfs-don-t-fail-xfs_extent_busy-allocation.patch queue-4.9/xfs-sync-eofblocks-scans-under-iolock-are-livelock-prone.patch queue-4.9/xfs-use-per-ag-reservations-for-the-finobt.patch queue-4.9/xfs-pull-up-iolock-from-xfs_free_eofblocks.patch queue-4.9/xfs-fail-_dir_open-when-readahead-fails.patch queue-4.9/xfs-update-ctime-and-mtime-on-clone-destinatation-inodes.patch queue-4.9/xfs-only-update-mount-resv-fields-on-success-in-__xfs_ag_resv_init.patch queue-4.9/xfs-use-xfs_icluster_size_fsb-to-calculate-inode-chunk-alignment.patch queue-4.9/xfs-only-reclaim-unwritten-cow-extents-periodically.patch queue-4.9/xfs-try-any-ag-when-allocating-the-first-btree-block-when-reflinking.patch queue-4.9/xfs-fix-and-streamline-error-handling-in-xfs_end_io.patch queue-4.9/xfs-fix-eofblocks-race-with-file-extending-async-dio-writes.patch