hostfs: convert to new aops

This also gets rid of a lot of useless read_file stuff. And also
optimises the full page write case by marking a !uptodate page uptodate.

Signed-off-by: Nick Piggin <npiggin@suse.de>
Cc: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/fs/hostfs/hostfs_kern.c b/fs/hostfs/hostfs_kern.c
index c77862032e844262a199549d01ca16489b0578f8..8a21289d774d9d8c8dacf4e98e10002d1ba72ec5 100644 (file)
--- a/fs/hostfs/hostfs_kern.c
+++ b/fs/hostfs/hostfs_kern.c
@@ -466,56 +466,42 @@ int hostfs_readpage(struct file *file, struct page *page)
        return err;
 }
 
-int hostfs_prepare_write(struct file *file, struct page *page,
-                        unsigned int from, unsigned int to)
+int hostfs_write_begin(struct file *file, struct address_space *mapping,
+                       loff_t pos, unsigned len, unsigned flags,
+                       struct page **pagep, void **fsdata)
 {
-       char *buffer;
-       long long start, tmp;
-       int err;
+       pgoff_t index = pos >> PAGE_CACHE_SHIFT;
 
-       start = (long long) page->index << PAGE_CACHE_SHIFT;
-       buffer = kmap(page);
-       if(from != 0){
-               tmp = start;
-               err = read_file(FILE_HOSTFS_I(file)->fd, &tmp, buffer,
-                               from);
-               if(err < 0) goto out;
-       }
-       if(to != PAGE_CACHE_SIZE){
-               start += to;
-               err = read_file(FILE_HOSTFS_I(file)->fd, &start, buffer + to,
-                               PAGE_CACHE_SIZE - to);
-               if(err < 0) goto out;
-       }
-       err = 0;
- out:
-       kunmap(page);
-       return err;
+       *pagep = __grab_cache_page(mapping, index);
+       if (!*pagep)
+               return -ENOMEM;
+       return 0;
 }
 
-int hostfs_commit_write(struct file *file, struct page *page, unsigned from,
-                unsigned to)
+int hostfs_write_end(struct file *file, struct address_space *mapping,
+                       loff_t pos, unsigned len, unsigned copied,
+                       struct page *page, void *fsdata)
 {
-       struct address_space *mapping = page->mapping;
        struct inode *inode = mapping->host;
-       char *buffer;
-       long long start;
-       int err = 0;
+       void *buffer;
+       unsigned from = pos & (PAGE_CACHE_SIZE - 1);
+       int err;
 
-       start = (((long long) page->index) << PAGE_CACHE_SHIFT) + from;
        buffer = kmap(page);
-       err = write_file(FILE_HOSTFS_I(file)->fd, &start, buffer + from,
-                        to - from);
-       if(err > 0) err = 0;
+       err = write_file(FILE_HOSTFS_I(file)->fd, &pos, buffer + from, copied);
+       kunmap(page);
 
-       /* Actually, if !err, write_file has added to-from to start, so, despite
-        * the appearance, we are comparing i_size against the _last_ written
-        * location, as we should. */
+       if (!PageUptodate(page) && err == PAGE_CACHE_SIZE)
+               SetPageUptodate(page);
 
-       if(!err && (start > inode->i_size))
-               inode->i_size = start;
+       /* If err > 0, write_file has added err to pos, so we are comparing
+        * i_size against the last byte written.
+        */
+       if (err > 0 && (pos > inode->i_size))
+               inode->i_size = pos;
+       unlock_page(page);
+       page_cache_release(page);
 
-       kunmap(page);
        return err;
 }
 
@@ -523,8 +509,8 @@ static const struct address_space_operations hostfs_aops = {
        .writepage      = hostfs_writepage,
        .readpage       = hostfs_readpage,
        .set_page_dirty = __set_page_dirty_nobuffers,
-       .prepare_write  = hostfs_prepare_write,
-       .commit_write   = hostfs_commit_write
+       .write_begin    = hostfs_write_begin,
+       .write_end      = hostfs_write_end,
 };
 
 static int init_inode(struct inode *inode, struct dentry *dentry)