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, 7 insertions, 19 deletions

diff --git a/fs/nilfs2/dir.c b/fs/nilfs2/dir.c
index 85c89dfc71f0..fc2bcfa599a3 100644
--- a/fs/nilfs2/dir.c
+++ b/fs/nilfs2/dir.c
@@ -80,23 +80,11 @@ static unsigned nilfs_last_byte(struct inode *inode, unsigned long page_nr)
         return last_byte;
 }
 
-static int nilfs_prepare_chunk_uninterruptible(struct page *page,
-                                               struct address_space *mapping,
-                                               unsigned from, unsigned to)
+static int nilfs_prepare_chunk(struct page *page, unsigned from, unsigned to)
 {
         loff_t pos = page_offset(page) + from;
-        return block_write_begin(NULL, mapping, pos, to - from,
-                                 AOP_FLAG_UNINTERRUPTIBLE, &page,
-                                 NULL, nilfs_get_block);
-}
-
-static int nilfs_prepare_chunk(struct page *page,
-                               struct address_space *mapping,
-                               unsigned from, unsigned to)
-{
-        loff_t pos = page_offset(page) + from;
-        return block_write_begin(NULL, mapping, pos, to - from, 0, &page,
-                                 NULL, nilfs_get_block);
+        return block_write_begin_newtrunc(NULL, page->mapping, pos, to - from,
+                                          0, &page, NULL, nilfs_get_block);
 }
 
 static void nilfs_commit_chunk(struct page *page,
@@ -449,7 +437,7 @@ void nilfs_set_link(struct inode *dir, struct nilfs_dir_entry *de,
         int err;
 
         lock_page(page);
-        err = nilfs_prepare_chunk_uninterruptible(page, mapping, from, to);
+        err = nilfs_prepare_chunk(page, from, to);
         BUG_ON(err);
         de->inode = cpu_to_le64(inode->i_ino);
         nilfs_set_de_type(de, inode);
@@ -530,7 +518,7 @@ int nilfs_add_link(struct dentry *dentry, struct inode *inode)
 got_it:
         from = (char *)de - (char *)page_address(page);
         to = from + rec_len;
-        err = nilfs_prepare_chunk(page, page->mapping, from, to);
+        err = nilfs_prepare_chunk(page, from, to);
         if (err)
                 goto out_unlock;
         if (de->inode) {
@@ -587,7 +575,7 @@ int nilfs_delete_entry(struct nilfs_dir_entry *dir, struct page *page)
         if (pde)
                 from = (char *)pde - (char *)page_address(page);
         lock_page(page);
-        err = nilfs_prepare_chunk(page, mapping, from, to);
+        err = nilfs_prepare_chunk(page, from, to);
         BUG_ON(err);
         if (pde)
                 pde->rec_len = cpu_to_le16(to - from);
@@ -615,7 +603,7 @@ int nilfs_make_empty(struct inode *inode, struct inode *parent)
         if (!page)
                 return -ENOMEM;
 
-        err = nilfs_prepare_chunk(page, mapping, 0, chunk_size);
+        err = nilfs_prepare_chunk(page, 0, chunk_size);
         if (unlikely(err)) {
                 unlock_page(page);
                 goto fail;