xfs: check for buffer errors before waiting
If we call xfs_buf_iowait() on a buffer that failed dispatch due to
an IO error, it will wait forever for an Io that does not exist.
This is hndled in xfs_buf_read, but there is other code that calls
xfs_buf_iowait directly that doesn't.
Rather than make the call sites have to handle checking for dispatch
errors and then checking for completion errors, make
xfs_buf_iowait() check for dispatch errors on the buffer before
waiting. This means we handle both dispatch and completion errors
with one set of error handling at the caller sites.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Mark Tinguely <tinguely@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
diff --git a/fs/xfs/xfs_buf.c b/fs/xfs/xfs_buf.c
index da2541e..86d9af7 100644
--- a/fs/xfs/xfs_buf.c
+++ b/fs/xfs/xfs_buf.c
@@ -600,17 +600,15 @@
xfs_buf_t *bp,
xfs_buf_flags_t flags)
{
- int status;
-
ASSERT(!(flags & XBF_WRITE));
ASSERT(bp->b_bn != XFS_BUF_DADDR_NULL);
bp->b_flags &= ~(XBF_WRITE | XBF_ASYNC | XBF_READ_AHEAD);
bp->b_flags |= flags & (XBF_READ | XBF_ASYNC | XBF_READ_AHEAD);
- status = xfs_buf_iorequest(bp);
- if (status || bp->b_error || (flags & XBF_ASYNC))
- return status;
+ xfs_buf_iorequest(bp);
+ if (flags & XBF_ASYNC)
+ return 0;
return xfs_buf_iowait(bp);
}
@@ -695,7 +693,7 @@
xfsbdstrat(mp, bp);
error = xfs_buf_iowait(bp);
- if (error || bp->b_error) {
+ if (error) {
xfs_buf_relse(bp);
return NULL;
}
@@ -1252,7 +1250,7 @@
}
}
-int
+void
xfs_buf_iorequest(
xfs_buf_t *bp)
{
@@ -1273,13 +1271,12 @@
_xfs_buf_ioend(bp, 0);
xfs_buf_rele(bp);
- return 0;
}
/*
- * Waits for I/O to complete on the buffer supplied.
- * It returns immediately if no I/O is pending.
- * It returns the I/O error code, if any, or 0 if there was no error.
+ * Waits for I/O to complete on the buffer supplied. It returns immediately if
+ * no I/O is pending or there is already a pending error on the buffer. It
+ * returns the I/O error code, if any, or 0 if there was no error.
*/
int
xfs_buf_iowait(
@@ -1287,7 +1284,8 @@
{
trace_xfs_buf_iowait(bp, _RET_IP_);
- wait_for_completion(&bp->b_iowait);
+ if (!bp->b_error)
+ wait_for_completion(&bp->b_iowait);
trace_xfs_buf_iowait_done(bp, _RET_IP_);
return bp->b_error;
