[PATCH RESEND] fs/buffer.c: call __block_write_begin() if we have page

[Namhyung Kim <namhyung@gmail.com>]

If we have the appropriate page already, call __block_write_begin()
directly instead of releasing and regrabbing it inside of
block_write_begin().

Signed-off-by: Namhyung Kim <namhyung@gmail.com>
---
Shared error path.

 fs/buffer.c |    9 ++++-----
 1 files changed, 4 insertions(+), 5 deletions(-)

diff --git a/fs/buffer.c b/fs/buffer.c
index 7f0b9b0..a132c2b 100644
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -2466,11 +2466,10 @@ int nobh_write_begin(struct address_space *mapping,
 	*fsdata = NULL;
 
 	if (page_has_buffers(page)) {
-		unlock_page(page);
-		page_cache_release(page);
-		*pagep = NULL;
-		return block_write_begin(mapping, pos, len, flags, pagep,
-					 get_block);
+		ret = __block_write_begin(page, pos, len, get_block);
+		if (unlikely(ret))
+			goto out_release;
+		return ret;
 	}
 
 	if (PageMappedToDisk(page))
-- 
1.7.0.4