Do not transfer a reference held by the caller to the buffer on the list,
or decrement it in xfs_buf_delwri_queue, but instead grab a new reference
if needed, and let the caller drop its own reference. Also move setting
of the XBF_DELWRI and XBF_ASYNC flags into xfs_buf_delwri_queue, and
only do it if needed. Note that for now xfs_buf_unlock already has
XBF_DELWRI, but that will change in the following patches.
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
Index: xfs/fs/xfs/xfs_buf.c
===================================================================
--- xfs.orig/fs/xfs/xfs_buf.c 2011-08-13 06:36:49.564247143 -0700
+++ xfs/fs/xfs/xfs_buf.c 2011-08-13 06:37:38.907313161 -0700
@@ -937,11 +937,8 @@ void
xfs_buf_unlock(
struct xfs_buf *bp)
{
- if ((bp->b_flags & (XBF_DELWRI|_XBF_DELWRI_Q)) == XBF_DELWRI) {
- atomic_inc(&bp->b_hold);
- bp->b_flags |= XBF_ASYNC;
+ if ((bp->b_flags & (XBF_DELWRI|_XBF_DELWRI_Q)) == XBF_DELWRI)
xfs_buf_delwri_queue(bp);
- }
XB_CLEAR_OWNER(bp);
up(&bp->b_sema);
@@ -1046,11 +1043,8 @@ xfs_bdwrite(
{
trace_xfs_buf_bdwrite(bp, _RET_IP_);
- bp->b_flags &= ~XBF_READ;
- bp->b_flags |= (XBF_DELWRI | XBF_ASYNC);
-
xfs_buf_delwri_queue(bp);
- xfs_buf_unlock(bp);
+ xfs_buf_relse(bp);
}
/*
@@ -1570,23 +1564,22 @@ xfs_buf_delwri_queue(
trace_xfs_buf_delwri_queue(bp, _RET_IP_);
- ASSERT((bp->b_flags&(XBF_DELWRI|XBF_ASYNC)) == (XBF_DELWRI|XBF_ASYNC));
+ ASSERT(!(bp->b_flags & XBF_READ));
spin_lock(dwlk);
- /* If already in the queue, dequeue and place at tail */
if (!list_empty(&bp->b_list)) {
+ /* if already in the queue, move it to the tail */
ASSERT(bp->b_flags & _XBF_DELWRI_Q);
- atomic_dec(&bp->b_hold);
- list_del(&bp->b_list);
- }
-
- if (list_empty(dwq)) {
+ list_move_tail(&bp->b_list, dwq);
+ } else {
/* start xfsbufd as it is about to have something to do */
- wake_up_process(bp->b_target->bt_task);
- }
+ if (list_empty(dwq))
+ wake_up_process(bp->b_target->bt_task);
- bp->b_flags |= _XBF_DELWRI_Q;
- list_add_tail(&bp->b_list, dwq);
+ atomic_inc(&bp->b_hold);
+ bp->b_flags |= XBF_DELWRI | _XBF_DELWRI_Q | XBF_ASYNC;
+ list_add_tail(&bp->b_list, dwq);
+ }
bp->b_queuetime = jiffies;
spin_unlock(dwlk);
}
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