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Commit 6b12c1b3 authored by Pavel Emelyanov's avatar Pavel Emelyanov Committed by Miklos Szeredi
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fuse: Implement write_begin/write_end callbacks 



The .write_begin and .write_end are requiered to use generic routines
(generic_file_aio_write --> ... --> generic_perform_write) for buffered
writes.

Signed-off-by: default avatarMaxim Patlasov <MPatlasov@parallels.com>
Signed-off-by: default avatarMiklos Szeredi <mszeredi@suse.cz>
parent 482fce55

fs/fuse/file.c

+73 −0
Original line number Original line Diff line number Diff line
@@ -1952,6 +1952,77 @@ static int fuse_writepages(struct address_space *mapping, 
	return err;

	return err;

}

}





/*

 * It's worthy to make sure that space is reserved on disk for the write,

 * but how to implement it without killing performance need more thinking.

 */

static int fuse_write_begin(struct file *file, struct address_space *mapping,

		loff_t pos, unsigned len, unsigned flags,

		struct page **pagep, void **fsdata)

{

	pgoff_t index = pos >> PAGE_CACHE_SHIFT;

	struct fuse_conn *fc = get_fuse_conn(file->f_dentry->d_inode);

	struct page *page;

	loff_t fsize;

	int err = -ENOMEM;



	WARN_ON(!fc->writeback_cache);



	page = grab_cache_page_write_begin(mapping, index, flags);

	if (!page)

		goto error;



	fuse_wait_on_page_writeback(mapping->host, page->index);



	if (PageUptodate(page) || len == PAGE_CACHE_SIZE)

		goto success;

	/*

	 * Check if the start this page comes after the end of file, in which

	 * case the readpage can be optimized away.

	 */

	fsize = i_size_read(mapping->host);

	if (fsize <= (pos & PAGE_CACHE_MASK)) {

		size_t off = pos & ~PAGE_CACHE_MASK;

		if (off)

			zero_user_segment(page, 0, off);

		goto success;

	}

	err = fuse_do_readpage(file, page);

	if (err)

		goto cleanup;

success:

	*pagep = page;

	return 0;



cleanup:

	unlock_page(page);

	page_cache_release(page);

error:

	return err;

}



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 = page->mapping->host;



	if (!PageUptodate(page)) {

		/* Zero any unwritten bytes at the end of the page */

		size_t endoff = (pos + copied) & ~PAGE_CACHE_MASK;

		if (endoff)

			zero_user_segment(page, endoff, PAGE_CACHE_SIZE);

		SetPageUptodate(page);

	}



	fuse_write_update_size(inode, pos + copied);

	set_page_dirty(page);

	unlock_page(page);

	page_cache_release(page);



	return copied;

}



static int fuse_launder_page(struct page *page)

static int fuse_launder_page(struct page *page)

{

{

	int err = 0;

	int err = 0;
@@ -2979,6 +3050,8 @@ static const struct address_space_operations fuse_file_aops = { 
	.set_page_dirty	= __set_page_dirty_nobuffers,

	.set_page_dirty	= __set_page_dirty_nobuffers,

	.bmap		= fuse_bmap,

	.bmap		= fuse_bmap,

	.direct_IO	= fuse_direct_IO,

	.direct_IO	= fuse_direct_IO,

	.write_begin	= fuse_write_begin,

	.write_end	= fuse_write_end,

};

};





void fuse_init_file_inode(struct inode *inode)

void fuse_init_file_inode(struct inode *inode)