1 files changed, 37 insertions, 10 deletions

diff --git a/fs/xfs/xfs_log_cil.c b/fs/xfs/xfs_log_cil.c
index ef652abd112c..ae9b8efcfa54 100644
--- a/fs/xfs/xfs_log_cil.c
+++ b/fs/xfs/xfs_log_cil.c
@@ -671,6 +671,12 @@ xlog_cil_push(
 	ASSERT(push_seq <= ctx->sequence);
 
 	/*
+	 * Wake up any background push waiters now this context is being pushed.
+	 */
+	if (ctx->space_used >= XLOG_CIL_BLOCKING_SPACE_LIMIT(log))
+		wake_up_all(&cil->xc_push_wait);
+
+	/*
 	 * Check if we've anything to push. If there is nothing, then we don't
 	 * move on to a new sequence number and so we have to be able to push
 	 * this sequence again later.
@@ -740,7 +746,7 @@ xlog_cil_push(
 
 	/*
 	 * initialise the new context and attach it to the CIL. Then attach
-	 * the current context to the CIL committing lsit so it can be found
+	 * the current context to the CIL committing list so it can be found
 	 * during log forces to extract the commit lsn of the sequence that
 	 * needs to be forced.
 	 */
@@ -900,7 +906,7 @@ xlog_cil_push_work(
  */
 static void
 xlog_cil_push_background(
-	struct xlog	*log)
+	struct xlog	*log) __releases(cil->xc_ctx_lock)
 {
 	struct xfs_cil	*cil = log->l_cilp;
 
@@ -914,14 +920,36 @@ xlog_cil_push_background(
 	 * don't do a background push if we haven't used up all the
 	 * space available yet.
 	 */
-	if (cil->xc_ctx->space_used < XLOG_CIL_SPACE_LIMIT(log))
+	if (cil->xc_ctx->space_used < XLOG_CIL_SPACE_LIMIT(log)) {
+		up_read(&cil->xc_ctx_lock);
 		return;
+	}
 
 	spin_lock(&cil->xc_push_lock);
 	if (cil->xc_push_seq < cil->xc_current_sequence) {
 		cil->xc_push_seq = cil->xc_current_sequence;
 		queue_work(log->l_mp->m_cil_workqueue, &cil->xc_push_work);
 	}
+
+	/*
+	 * Drop the context lock now, we can't hold that if we need to sleep
+	 * because we are over the blocking threshold. The push_lock is still
+	 * held, so blocking threshold sleep/wakeup is still correctly
+	 * serialised here.
+	 */
+	up_read(&cil->xc_ctx_lock);
+
+	/*
+	 * If we are well over the space limit, throttle the work that is being
+	 * done until the push work on this context has begun.
+	 */
+	if (cil->xc_ctx->space_used >= XLOG_CIL_BLOCKING_SPACE_LIMIT(log)) {
+		trace_xfs_log_cil_wait(log, cil->xc_ctx->ticket);
+		ASSERT(cil->xc_ctx->space_used < log->l_logsize);
+		xlog_wait(&cil->xc_push_wait, &cil->xc_push_lock);
+		return;
+	}
+
 	spin_unlock(&cil->xc_push_lock);
 
 }
@@ -1038,9 +1066,9 @@ xfs_log_commit_cil(
 		if (lip->li_ops->iop_committing)
 			lip->li_ops->iop_committing(lip, xc_commit_lsn);
 	}
-	xlog_cil_push_background(log);
 
-	up_read(&cil->xc_ctx_lock);
+	/* xlog_cil_push_background() releases cil->xc_ctx_lock */
+	xlog_cil_push_background(log);
 }
 
 /*
@@ -1150,21 +1178,19 @@ out_shutdown:
  */
 bool
 xfs_log_item_in_current_chkpt(
-	struct xfs_log_item *lip)
+	struct xfs_log_item	*lip)
 {
-	struct xfs_cil_ctx *ctx;
+	struct xfs_cil		*cil = lip->li_mountp->m_log->l_cilp;
 
 	if (list_empty(&lip->li_cil))
 		return false;
 
-	ctx = lip->li_mountp->m_log->l_cilp->xc_ctx;
-
 	/*
 	 * li_seq is written on the first commit of a log item to record the
 	 * first checkpoint it is written to. Hence if it is different to the
 	 * current sequence, we're in a new checkpoint.
 	 */
-	if (XFS_LSN_CMP(lip->li_seq, ctx->sequence) != 0)
+	if (XFS_LSN_CMP(lip->li_seq, READ_ONCE(cil->xc_current_sequence)) != 0)
 		return false;
 	return true;
 }
@@ -1194,6 +1220,7 @@ xlog_cil_init(
 	INIT_LIST_HEAD(&cil->xc_committing);
 	spin_lock_init(&cil->xc_cil_lock);
 	spin_lock_init(&cil->xc_push_lock);
+	init_waitqueue_head(&cil->xc_push_wait);
 	init_rwsem(&cil->xc_ctx_lock);
 	init_waitqueue_head(&cil->xc_commit_wait);