From 61be9c529a4a715ab8679e9ca82bc3790c7ab66c Mon Sep 17 00:00:00 2001 From: Dave Chinner Date: Thu, 2 Oct 2014 09:04:31 +1000 Subject: [PATCH] xfs: rework xfs_buf_bio_endio error handling Currently the report of a bio error from completion immediately marks the buffer with an error. The issue is that this is racy w.r.t. synchronous IO - the submitter can see b_error being set before the IO is complete, and hence we cannot differentiate between submission failures and completion failures. Add an internal b_io_error field protected by the b_lock to catch IO completion errors, and only propagate that to the buffer during final IO completion handling. Hence we can tell in xfs_buf_iorequest if we've had a submission failure bey checking bp->b_error before dropping our b_io_remaining reference - that reference will prevent b_io_error values from being propagated to b_error in the event that completion races with submission. Signed-off-by: Dave Chinner Reviewed-by: Christoph Hellwig Signed-off-by: Dave Chinner --- Reading git-format-patch failed