From 3c72afb2b3afdd38ec486dc6e2b72095e38ebec5 Mon Sep 17 00:00:00 2001
From: Jens Axboe <jens.axboe@oracle.com>
Date: Thu, 15 Jan 2009 14:44:25 +0100
Subject: [PATCH] aio: first support for buffered async writes

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
---
 fs/buffer.c             |  5 +----
 fs/ext3/inode.c         |  2 ++
 include/linux/pagemap.h |  2 ++
 mm/filemap.c            | 44 ++++++++++++++++++++++++++++-------------
 mm/page-writeback.c     |  4 +++-
 5 files changed, 38 insertions(+), 19 deletions(-)

diff --git a/fs/buffer.c b/fs/buffer.c
index 9bbae13011ce..25b307128b2e 100644
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -3369,10 +3369,7 @@ int bh_submit_read(struct buffer_head *bh)
 	get_bh(bh);
 	bh->b_end_io = end_buffer_read_sync;
 	submit_bh(READ, bh);
-	if (wait_on_buffer_async(bh, current->io_wait)) {
-		WARN(1, "%s: err\n", __FUNCTION__);
-		return -EIOCBRETRY;
-	}
+	wait_on_buffer(bh);
 	if (buffer_uptodate(bh))
 		return 0;
 	return -EIO;
diff --git a/fs/ext3/inode.c b/fs/ext3/inode.c
index acf1b1423327..d59b237f349c 100644
--- a/fs/ext3/inode.c
+++ b/fs/ext3/inode.c
@@ -1171,6 +1171,8 @@ retry:
 	page = grab_cache_page_write_begin(mapping, index, flags);
 	if (!page)
 		return -ENOMEM;
+	else if (IS_ERR(page))
+		return PTR_ERR(page);
 	*pagep = page;
 
 	handle = ext3_journal_start(inode, needed_blocks);
diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
index 3c80f3a45688..0d154a789441 100644
--- a/include/linux/pagemap.h
+++ b/include/linux/pagemap.h
@@ -224,6 +224,8 @@ extern struct page * find_get_page(struct address_space *mapping,
 				pgoff_t index);
 extern struct page * find_lock_page(struct address_space *mapping,
 				pgoff_t index);
+extern struct page *find_lock_page_async(struct address_space *mapping,
+				pgoff_t index, struct wait_bit_queue *wait);
 extern struct page * find_or_create_page(struct address_space *mapping,
 				pgoff_t index, gfp_t gfp_mask);
 unsigned find_get_pages(struct address_space *mapping, pgoff_t start,
diff --git a/mm/filemap.c b/mm/filemap.c
index 4fffb32ba3a7..26348d3bdcb4 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -693,24 +693,22 @@ repeat:
 }
 EXPORT_SYMBOL(find_get_page);
 
-/**
- * find_lock_page - locate, pin and lock a pagecache page
- * @mapping: the address_space to search
- * @offset: the page index
- *
- * Locates the desired pagecache page, locks it, increments its reference
- * count and returns its address.
- *
- * Returns zero if the page was not present. find_lock_page() may sleep.
- */
-struct page *find_lock_page(struct address_space *mapping, pgoff_t offset)
+struct page *find_lock_page_async(struct address_space *mapping, pgoff_t offset,
+				  struct wait_bit_queue *wait)
 {
 	struct page *page;
 
 repeat:
 	page = find_get_page(mapping, offset);
 	if (page) {
-		lock_page(page);
+		int ret;
+
+		ret = lock_page_async(page, wait);
+		if (ret) {
+			page_cache_release(page);
+			page = ERR_PTR(ret);
+			goto out;
+		}
 		/* Has the page been truncated? */
 		if (unlikely(page->mapping != mapping)) {
 			unlock_page(page);
@@ -719,8 +717,26 @@ repeat:
 		}
 		VM_BUG_ON(page->index != offset);
 	}
+out:
 	return page;
 }
+EXPORT_SYMBOL(find_lock_page_async);
+
+/**
+ * find_lock_page - locate, pin and lock a pagecache page
+ * @mapping: the address_space to search
+ * @offset: the page index
+ *
+ * Locates the desired pagecache page, locks it, increments its reference
+ * count and returns its address.
+ *
+ * Returns zero if the page was not present. find_lock_page() may sleep.
+ */
+struct page *find_lock_page(struct address_space *mapping, pgoff_t offset)
+{
+
+	return find_lock_page_async(mapping, offset, NULL);
+}
 EXPORT_SYMBOL(find_lock_page);
 
 /**
@@ -2183,8 +2199,8 @@ struct page *grab_cache_page_write_begin(struct address_space *mapping,
 	if (flags & AOP_FLAG_NOFS)
 		gfp_notmask = __GFP_FS;
 repeat:
-	page = find_lock_page(mapping, index);
-	if (likely(page))
+	page = find_lock_page_async(mapping, index, current->io_wait);
+	if (page || IS_ERR(page))
 		return page;
 
 	page = __page_cache_alloc(mapping_gfp_mask(mapping) & ~gfp_notmask);
diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index 69b5fbabc8bd..4be7cc5243d4 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -886,7 +886,9 @@ retry:
 
 			done_index = page->index + 1;
 
-			lock_page(page);
+			ret = lock_page_async(page, current->io_wait);
+			if (ret)
+				break;
 
 			/*
 			 * Page truncated or invalidated. We can freely skip it
-- 
2.25.1