Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux-block into for-3.18

This is to receive 0a30288da1ae ("blk-mq, percpu_ref: implement a
kludge for SCSI blk-mq stall during probe") which implements
__percpu_ref_kill_expedited() to work around SCSI blk-mq stall.  The
commit reverted and patches to implement proper fix will be added.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Kent Overstreet <kmo@daterainc.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Christoph Hellwig <hch@lst.de>

1 files changed, 21 insertions, 4 deletions

diff --git a/fs/fscache/page.c b/fs/fscache/page.c
index 85332b9d19d1..de33b3fccca6 100644
--- a/fs/fscache/page.c
+++ b/fs/fscache/page.c
@@ -44,6 +44,19 @@ void __fscache_wait_on_page_write(struct fscache_cookie *cookie, struct page *pa
 EXPORT_SYMBOL(__fscache_wait_on_page_write);
 
 /*
+ * wait for a page to finish being written to the cache. Put a timeout here
+ * since we might be called recursively via parent fs.
+ */
+static
+bool release_page_wait_timeout(struct fscache_cookie *cookie, struct page *page)
+{
+	wait_queue_head_t *wq = bit_waitqueue(&cookie->flags, 0);
+
+	return wait_event_timeout(*wq, !__fscache_check_page_write(cookie, page),
+				  HZ);
+}
+
+/*
  * decide whether a page can be released, possibly by cancelling a store to it
  * - we're allowed to sleep if __GFP_WAIT is flagged
  */
@@ -115,7 +128,10 @@ page_busy:
 	}
 
 	fscache_stat(&fscache_n_store_vmscan_wait);
-	__fscache_wait_on_page_write(cookie, page);
+	if (!release_page_wait_timeout(cookie, page))
+		_debug("fscache writeout timeout page: %p{%lx}",
+			page, page->index);
+
 	gfp &= ~__GFP_WAIT;
 	goto try_again;
 }
@@ -182,7 +198,7 @@ int __fscache_attr_changed(struct fscache_cookie *cookie)
 {
 	struct fscache_operation *op;
 	struct fscache_object *object;
-	bool wake_cookie;
+	bool wake_cookie = false;
 
 	_enter("%p", cookie);
 
@@ -212,15 +228,16 @@ int __fscache_attr_changed(struct fscache_cookie *cookie)
 
 	__fscache_use_cookie(cookie);
 	if (fscache_submit_exclusive_op(object, op) < 0)
-		goto nobufs;
+		goto nobufs_dec;
 	spin_unlock(&cookie->lock);
 	fscache_stat(&fscache_n_attr_changed_ok);
 	fscache_put_operation(op);
 	_leave(" = 0");
 	return 0;
 
-nobufs:
+nobufs_dec:
 	wake_cookie = __fscache_unuse_cookie(cookie);
+nobufs:
 	spin_unlock(&cookie->lock);
 	kfree(op);
 	if (wake_cookie)