fuse: convert to new aops

[mszeredi]
 - don't send zero length write requests
 - it is not legal for the filesystem to return with zero written bytes

Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/fs/fuse/file.c b/fs/fuse/file.c
index f79de7c8cdfaae3260009c86127f88ae4283cc22..11f22a3d728a747212066c107533313f1eaf9f01 100644 (file)
--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -444,22 +444,25 @@ static size_t fuse_send_write(struct fuse_req *req, struct file *file,
        return outarg.size;
 }
 
-static int fuse_prepare_write(struct file *file, struct page *page,
-                             unsigned offset, unsigned to)
+static int fuse_write_begin(struct file *file, struct address_space *mapping,
+                       loff_t pos, unsigned len, unsigned flags,
+                       struct page **pagep, void **fsdata)
 {
-       /* No op */
+       pgoff_t index = pos >> PAGE_CACHE_SHIFT;
+
+       *pagep = __grab_cache_page(mapping, index);
+       if (!*pagep)
+               return -ENOMEM;
        return 0;
 }
 
-static int fuse_commit_write(struct file *file, struct page *page,
-                            unsigned offset, unsigned to)
+static int fuse_buffered_write(struct file *file, struct inode *inode,
+                              loff_t pos, unsigned count, struct page *page)
 {
        int err;
        size_t nres;
-       unsigned count = to - offset;
-       struct inode *inode = page->mapping->host;
        struct fuse_conn *fc = get_fuse_conn(inode);
-       loff_t pos = page_offset(page) + offset;
+       unsigned offset = pos & (PAGE_CACHE_SIZE - 1);
        struct fuse_req *req;
 
        if (is_bad_inode(inode))
@@ -475,20 +478,35 @@ static int fuse_commit_write(struct file *file, struct page *page,
        nres = fuse_send_write(req, file, inode, pos, count);
        err = req->out.h.error;
        fuse_put_request(fc, req);
-       if (!err && nres != count)
+       if (!err && !nres)
                err = -EIO;
        if (!err) {
-               pos += count;
+               pos += nres;
                spin_lock(&fc->lock);
                if (pos > inode->i_size)
                        i_size_write(inode, pos);
                spin_unlock(&fc->lock);
 
-               if (offset == 0 && to == PAGE_CACHE_SIZE)
+               if (count == PAGE_CACHE_SIZE)
                        SetPageUptodate(page);
        }
        fuse_invalidate_attr(inode);
-       return err;
+       return err ? err : nres;
+}
+
+static int fuse_write_end(struct file *file, struct address_space *mapping,
+                       loff_t pos, unsigned len, unsigned copied,
+                       struct page *page, void *fsdata)
+{
+       struct inode *inode = mapping->host;
+       int res = 0;
+
+       if (copied)
+               res = fuse_buffered_write(file, inode, pos, copied, page);
+
+       unlock_page(page);
+       page_cache_release(page);
+       return res;
 }
 
 static void fuse_release_user_pages(struct fuse_req *req, int write)
@@ -819,8 +837,8 @@ static const struct file_operations fuse_direct_io_file_operations = {
 
 static const struct address_space_operations fuse_file_aops  = {
        .readpage       = fuse_readpage,
-       .prepare_write  = fuse_prepare_write,
-       .commit_write   = fuse_commit_write,
+       .write_begin    = fuse_write_begin,
+       .write_end      = fuse_write_end,
        .readpages      = fuse_readpages,
        .set_page_dirty = fuse_set_page_dirty,
        .bmap           = fuse_bmap,