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authorDave Chinner <dchinner@redhat.com>2014-10-02 09:04:31 +1000
committerDave Chinner <david@fromorbit.com>2014-10-02 09:04:31 +1000
commit61be9c529a4a715ab8679e9ca82bc3790c7ab66c (patch)
tree3e8d1c757133eb7c844cd4ba8815f4a6bc0218cb /fs/xfs/xfs_buf.h
parente8aaba9a783c8e5d2c58ebe69650ea31b91bb745 (diff)
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 <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Dave Chinner <david@fromorbit.com>
Diffstat (limited to 'fs/xfs/xfs_buf.h')
-rw-r--r--fs/xfs/xfs_buf.h1
1 files changed, 1 insertions, 0 deletions
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 */