1 files changed, 9 insertions, 17 deletions

diff --git a/fs/buffer.c b/fs/buffer.c
index 8d595ab2aed1..5930e382959b 100644
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -1833,9 +1833,11 @@ void page_zero_new_buffers(struct page *page, unsigned from, unsigned to)
 }
 EXPORT_SYMBOL(page_zero_new_buffers);
 
-int block_prepare_write(struct page *page, unsigned from, unsigned to,
+int __block_write_begin(struct page *page, loff_t pos, unsigned len,
                 get_block_t *get_block)
 {
+        unsigned from = pos & (PAGE_CACHE_SIZE - 1);
+        unsigned to = from + len;
         struct inode *inode = page->mapping->host;
         unsigned block_start, block_end;
         sector_t block;
@@ -1915,7 +1917,7 @@ int block_prepare_write(struct page *page, unsigned from, unsigned to,
         }
         return err;
 }
-EXPORT_SYMBOL(block_prepare_write);
+EXPORT_SYMBOL(__block_write_begin);
 
 static int __block_commit_write(struct inode *inode, struct page *page,
                 unsigned from, unsigned to)
@@ -1952,15 +1954,6 @@ static int __block_commit_write(struct inode *inode, struct page *page,
         return 0;
 }
 
-int __block_write_begin(struct page *page, loff_t pos, unsigned len,
-                get_block_t *get_block)
-{
-        unsigned start = pos & (PAGE_CACHE_SIZE - 1);
-
-        return block_prepare_write(page, start, start + len, get_block);
-}
-EXPORT_SYMBOL(__block_write_begin);
-
 /*
  * block_write_begin takes care of the basic task of block allocation and
  * bringing partial write blocks uptodate first.
@@ -2378,7 +2371,7 @@ block_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf,
         else
                 end = PAGE_CACHE_SIZE;
 
-        ret = block_prepare_write(page, 0, end, get_block);
+        ret = __block_write_begin(page, 0, end, get_block);
         if (!ret)
                 ret = block_commit_write(page, 0, end);
 
@@ -2465,11 +2458,10 @@ 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))