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Commit 59c3b76c authored by Miklos Szeredi's avatar Miklos Szeredi
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fuse: fix fuse_write_end() if zero bytes were copied 



If pos is at the beginning of a page and copied is zero then page is not
zeroed but is marked uptodate.

Fix by skipping everything except unlock/put of page if zero bytes were
copied.

Reported-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
Fixes: 6b12c1b3 ("fuse: Implement write_begin/write_end callbacks")
Cc: <stable@vger.kernel.org> # v3.15+
Signed-off-by: default avatarMiklos Szeredi <mszeredi@redhat.com>
parent 0ce267ff

fs/fuse/file.c

+6 −0
Original line number Original line Diff line number Diff line
@@ -1985,6 +1985,10 @@ static int fuse_write_end(struct file *file, struct address_space *mapping, 
{

{

	struct inode *inode = page->mapping->host;

	struct inode *inode = page->mapping->host;





	/* Haven't copied anything?  Skip zeroing, size extending, dirtying. */

	if (!copied)

		goto unlock;



	if (!PageUptodate(page)) {

	if (!PageUptodate(page)) {

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

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

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

		size_t endoff = (pos + copied) & ~PAGE_MASK;
@@ -1995,6 +1999,8 @@ static int fuse_write_end(struct file *file, struct address_space *mapping, 




	fuse_write_update_size(inode, pos + copied);

	fuse_write_update_size(inode, pos + copied);

	set_page_dirty(page);

	set_page_dirty(page);



unlock:

	unlock_page(page);

	unlock_page(page);

	put_page(page);

	put_page(page);