fs: new cont helpers

Rework the generic block "cont" routines to handle the new aops.  Supporting
cont_prepare_write would take quite a lot of code to support, so remove it
instead (and we later convert all filesystems to use it).

write_begin gets passed AOP_FLAG_CONT_EXPAND when called from
generic_cont_expand, so filesystems can avoid the old hacks they used.

Signed-off-by: Nick Piggin <npiggin@suse.de>
Cc: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

2 files changed, 4 insertions, 2 deletions

diff --git a/include/linux/buffer_head.h b/include/linux/buffer_head.h
index a562ecfb1a14..1caa71d4c95f 100644
--- a/include/linux/buffer_head.h
+++ b/include/linux/buffer_head.h
@@ -214,8 +214,9 @@ int generic_write_end(struct file *, struct address_space *,
                                 struct page *, void *);
 void page_zero_new_buffers(struct page *page, unsigned from, unsigned to);
 int block_prepare_write(struct page*, unsigned, unsigned, get_block_t*);
-int cont_prepare_write(struct page*, unsigned, unsigned, get_block_t*,
-                                loff_t *);
+int cont_write_begin(struct file *, struct address_space *, loff_t,
+                        unsigned, unsigned, struct page **, void **,
+                        get_block_t *, loff_t *);
 int generic_cont_expand(struct inode *inode, loff_t size);
 int generic_cont_expand_simple(struct inode *inode, loff_t size);
 int block_commit_write(struct page *page, unsigned from, unsigned to);
diff --git a/include/linux/fs.h b/include/linux/fs.h
index e9344e6f877d..a40557eae2ed 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -395,6 +395,7 @@ enum positive_aop_returns {
 };
 
 #define AOP_FLAG_UNINTERRUPTIBLE        0x0001 /* will not do a short write */
+#define AOP_FLAG_CONT_EXPAND            0x0002 /* called from cont_expand */
 
 /*
  * oh the beauties of C type declarations.