fs: remove prepare_write/commit_write

Nothing uses prepare_write or commit_write. Remove them from the tree
completely.

[akpm@linux-foundation.org: schedule simple_prepare_write() for unexporting]
Signed-off-by: Nick Piggin <npiggin@suse.de>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

2 files changed, 12 insertions, 39 deletions

diff --git a/Documentation/filesystems/Locking b/Documentation/filesystems/Locking
index 8362860e21a7..23d2f4460deb 100644
--- a/Documentation/filesystems/Locking
+++ b/Documentation/filesystems/Locking
@@ -161,8 +161,12 @@ prototypes:
         int (*set_page_dirty)(struct page *page);
         int (*readpages)(struct file *filp, struct address_space *mapping,
                         struct list_head *pages, unsigned nr_pages);
-        int (*prepare_write)(struct file *, struct page *, unsigned, unsigned);
-        int (*commit_write)(struct file *, struct page *, unsigned, unsigned);
+        int (*write_begin)(struct file *, struct address_space *mapping,
+                                loff_t pos, unsigned len, unsigned flags,
+                                struct page **pagep, void **fsdata);
+        int (*write_end)(struct file *, struct address_space *mapping,
+                                loff_t pos, unsigned len, unsigned copied,
+                                struct page *page, void *fsdata);
         sector_t (*bmap)(struct address_space *, sector_t);
         int (*invalidatepage) (struct page *, unsigned long);
         int (*releasepage) (struct page *, int);
@@ -180,8 +184,6 @@ sync_page:		no	maybe
 writepages:             no
 set_page_dirty          no      no
 readpages:              no
-prepare_write:          no      yes                     yes
-commit_write:           no      yes                     yes
 write_begin:            no      locks the page          yes
 write_end:              no      yes, unlocks            yes
 perform_write:          no      n/a                     yes
@@ -191,7 +193,7 @@ releasepage:		no	yes
 direct_IO:              no
 launder_page:           no      yes
 
-        ->prepare_write(), ->commit_write(), ->sync_page() and ->readpage()
+        ->write_begin(), ->write_end(), ->sync_page() and ->readpage()
 may be called from the request handler (/dev/loop).
 
         ->readpage() unlocks the page, either synchronously or via I/O
diff --git a/Documentation/filesystems/vfs.txt b/Documentation/filesystems/vfs.txt
index c4d348dabe94..5579bda58a6d 100644
--- a/Documentation/filesystems/vfs.txt
+++ b/Documentation/filesystems/vfs.txt
@@ -492,7 +492,7 @@ written-back to storage typically in whole pages, however the
 address_space has finer control of write sizes.
 
 The read process essentially only requires 'readpage'.  The write
-process is more complicated and uses prepare_write/commit_write or
+process is more complicated and uses write_begin/write_end or
 set_page_dirty to write data into the address_space, and writepage,
 sync_page, and writepages to writeback data to storage.
 
@@ -521,8 +521,6 @@ struct address_space_operations {
         int (*set_page_dirty)(struct page *page);
         int (*readpages)(struct file *filp, struct address_space *mapping,
                         struct list_head *pages, unsigned nr_pages);
-        int (*prepare_write)(struct file *, struct page *, unsigned, unsigned);
-        int (*commit_write)(struct file *, struct page *, unsigned, unsigned);
         int (*write_begin)(struct file *, struct address_space *mapping,
                                 loff_t pos, unsigned len, unsigned flags,
                                 struct page **pagep, void **fsdata);
@@ -598,37 +596,7 @@ struct address_space_operations {
         readpages is only used for read-ahead, so read errors are
         ignored.  If anything goes wrong, feel free to give up.
 
-  prepare_write: called by the generic write path in VM to set up a write
-        request for a page.  This indicates to the address space that
-        the given range of bytes is about to be written.  The
-        address_space should check that the write will be able to
-        complete, by allocating space if necessary and doing any other
-        internal housekeeping.  If the write will update parts of
-        any basic-blocks on storage, then those blocks should be
-        pre-read (if they haven't been read already) so that the
-        updated blocks can be written out properly.
-        The page will be locked.
-
-        Note: the page _must not_ be marked uptodate in this function
-        (or anywhere else) unless it actually is uptodate right now. As
-        soon as a page is marked uptodate, it is possible for a concurrent
-        read(2) to copy it to userspace.
-
-  commit_write: If prepare_write succeeds, new data will be copied
-        into the page and then commit_write will be called.  It will
-        typically update the size of the file (if appropriate) and
-        mark the inode as dirty, and do any other related housekeeping
-        operations.  It should avoid returning an error if possible -
-        errors should have been handled by prepare_write.
-
-  write_begin: This is intended as a replacement for prepare_write. The
-        key differences being that:
-                - it returns a locked page (in *pagep) rather than being
-                  given a pre locked page;
-                - it must be able to cope with short writes (where the
-                  length passed to write_begin is greater than the number
-                  of bytes copied into the page).
-
+  write_begin:
         Called by the generic buffered write code to ask the filesystem to
         prepare to write len bytes at the given offset in the file. The
         address_space should check that the write will be able to complete,
@@ -640,6 +608,9 @@ struct address_space_operations {
         The filesystem must return the locked pagecache page for the specified
         offset, in *pagep, for the caller to write into.
 
+        It must be able to cope with short writes (where the length passed to
+        write_begin is greater than the number of bytes copied into the page).
+
         flags is a field for AOP_FLAG_xxx flags, described in
         include/linux/fs.h.