From 61be9c529a4a715ab8679e9ca82bc3790c7ab66c Mon Sep 17 00:00:00 2001 From: Dave Chinner Date: Thu, 2 Oct 2014 09:04:31 +1000 Subject: 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 --- fs/xfs/xfs_buf.h | 1 + 1 file changed, 1 insertion(+) (limited to 'fs/xfs/xfs_buf.h') diff --git a/fs/xfs/xfs_buf.h b/fs/xfs/xfs_buf.h index 4585c1595a98..44db8cd67bda 100644 --- a/fs/xfs/xfs_buf.h +++ b/fs/xfs/xfs_buf.h @@ -158,6 +158,7 @@ typedef struct xfs_buf { struct list_head b_lru; /* lru list */ spinlock_t b_lock; /* internal state lock */ unsigned int b_state; /* internal state flags */ + int b_io_error; /* internal IO error state */ wait_queue_head_t b_waiters; /* unpin waiters */ struct list_head b_list; struct xfs_perag *b_pag; /* contains rbtree root */ -- cgit v1.2.3