clean up write_begin usage for directories in pagecache

For filesystem that implement directories in pagecache we call
block_write_begin with an already allocated page for this code, while the
normal regular file write path uses the default block_write_begin behaviour.

Get rid of the __foofs_write_begin helper and opencode the normal write_begin
call in foofs_write_begin, while adding a new foofs_prepare_chunk helper for
the directory code.  The added benefit is that foofs_prepare_chunk has
a much saner calling convention.

Note that the interruptible flag passed into block_write_begin is always
ignored if we already pass in a page (see next patch for details), and
we never were doing truncations of exessive blocks for this case either so we
can switch directly to block_write_begin_newtrunc.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 12 insertions, 12 deletions

diff --git a/fs/ext2/dir.c b/fs/ext2/dir.c
index 7516957..6b946ba 100644
--- a/fs/ext2/dir.c
+++ b/fs/ext2/dir.c
@@ -448,6 +448,12 @@ ino_t ext2_inode_by_name(struct inode *dir, struct qstr *child)
 	return res;
 }
 
+static int ext2_prepare_chunk(struct page *page, loff_t pos, unsigned len)
+{
+	return block_write_begin_newtrunc(NULL, page->mapping, pos, len, 0,
+					  &page, NULL, ext2_get_block);
+}
+
 /* Releases the page */
 void ext2_set_link(struct inode *dir, struct ext2_dir_entry_2 *de,
 		   struct page *page, struct inode *inode, int update_times)
@@ -458,8 +464,7 @@ void ext2_set_link(struct inode *dir, struct ext2_dir_entry_2 *de,
 	int err;
 
 	lock_page(page);
-	err = __ext2_write_begin(NULL, page->mapping, pos, len,
-				AOP_FLAG_UNINTERRUPTIBLE, &page, NULL);
+	err = ext2_prepare_chunk(page, pos, len);
 	BUG_ON(err);
 	de->inode = cpu_to_le32(inode->i_ino);
 	ext2_set_de_type(de, inode);
@@ -542,8 +547,7 @@ int ext2_add_link (struct dentry *dentry, struct inode *inode)
 got_it:
 	pos = page_offset(page) +
 		(char*)de - (char*)page_address(page);
-	err = __ext2_write_begin(NULL, page->mapping, pos, rec_len, 0,
-							&page, NULL);
+	err = ext2_prepare_chunk(page, pos, rec_len);
 	if (err)
 		goto out_unlock;
 	if (de->inode) {
@@ -576,8 +580,7 @@ out_unlock:
  */
 int ext2_delete_entry (struct ext2_dir_entry_2 * dir, struct page * page )
 {
-	struct address_space *mapping = page->mapping;
-	struct inode *inode = mapping->host;
+	struct inode *inode = page->mapping->host;
 	char *kaddr = page_address(page);
 	unsigned from = ((char*)dir - kaddr) & ~(ext2_chunk_size(inode)-1);
 	unsigned to = ((char *)dir - kaddr) +
@@ -601,8 +604,7 @@ int ext2_delete_entry (struct ext2_dir_entry_2 * dir, struct page * page )
 		from = (char*)pde - (char*)page_address(page);
 	pos = page_offset(page) + from;
 	lock_page(page);
-	err = __ext2_write_begin(NULL, page->mapping, pos, to - from, 0,
-							&page, NULL);
+	err = ext2_prepare_chunk(page, pos, to - from);
 	BUG_ON(err);
 	if (pde)
 		pde->rec_len = ext2_rec_len_to_disk(to - from);
@@ -621,8 +623,7 @@ out:
  */
 int ext2_make_empty(struct inode *inode, struct inode *parent)
 {
-	struct address_space *mapping = inode->i_mapping;
-	struct page *page = grab_cache_page(mapping, 0);
+	struct page *page = grab_cache_page(inode->i_mapping, 0);
 	unsigned chunk_size = ext2_chunk_size(inode);
 	struct ext2_dir_entry_2 * de;
 	int err;
@@ -631,8 +632,7 @@ int ext2_make_empty(struct inode *inode, struct inode *parent)
 	if (!page)
 		return -ENOMEM;
 
-	err = __ext2_write_begin(NULL, page->mapping, 0, chunk_size, 0,
-							&page, NULL);
+	err = ext2_prepare_chunk(page, 0, chunk_size);
 	if (err) {
 		unlock_page(page);
 		goto fail;