[PATCH 4.10 25/81] xfs: fix and streamline error handling in xfs_end_io

Greg Kroah-Hartman
2017-04-06T09:05:29Z

From: Christoph Hellwig <hch@lst.de>

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.

Signed-off-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>

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

--- a/fs/xfs/xfs_aops.c
+++ b/fs/xfs/xfs_aops.c
@@ -274,54 +274,49 @@ 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);
}