xfs: don't block on buffer read errors
xfs_buf_read() fails to detect dispatch errors before attempting to
wait on sychronous IO. If there was an error, it will get stuck
forever, waiting for an I/O that was never started. Make sure the
error is detected correctly.
Further, such a failure can leave locked pages in the page cache
which will cause a later operation to hang on the page. Ensure that
we correctly process pages in the buffers when we get a dispatch
error.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dave Chinner <david@fromorbit.com>
diff --git a/fs/xfs/linux-2.6/xfs_buf.c b/fs/xfs/linux-2.6/xfs_buf.c
index efce8abb..f4d4e70 100644
--- a/fs/xfs/linux-2.6/xfs_buf.c
+++ b/fs/xfs/linux-2.6/xfs_buf.c
@@ -578,9 +578,9 @@
XBF_READ_AHEAD | _XBF_RUN_QUEUES);
status = xfs_buf_iorequest(bp);
- if (!status && !(flags & XBF_ASYNC))
- status = xfs_buf_iowait(bp);
- return status;
+ if (status || XFS_BUF_ISERROR(bp) || (flags & XBF_ASYNC))
+ return status;
+ return xfs_buf_iowait(bp);
}
xfs_buf_t *
@@ -1280,8 +1280,19 @@
if (size)
goto next_chunk;
} else {
- bio_put(bio);
+ /*
+ * if we get here, no pages were added to the bio. However,
+ * we can't just error out here - if the pages are locked then
+ * we have to unlock them otherwise we can hang on a later
+ * access to the page.
+ */
xfs_buf_ioerror(bp, EIO);
+ if (bp->b_flags & _XBF_PAGE_LOCKED) {
+ int i;
+ for (i = 0; i < bp->b_page_count; i++)
+ unlock_page(bp->b_pages[i]);
+ }
+ bio_put(bio);
}
}
