fuse: fix fuse_write_end() if zero bytes were copied (59c3b76c) · Commits · 戴 / test

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:

Al Viro <viro@zeniv.linux.org.uk> Fixes: ("fuse: Implement write_begin/write_end callbacks") Cc: <stable@vger.kernel.org> # v3.15+ Signed-off-by:

Miklos Szeredi <mszeredi@redhat.com>

fs/fuse/file.c

+6 −0

Original line number	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;

		/* Haven't copied anything? Skip zeroing, size extending, dirtying. */
		if (!copied)
		goto unlock;

		if (!PageUptodate(page)) {
		/* Zero any unwritten bytes at the end of the page */
		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);
		set_page_dirty(page);

		unlock:
		unlock_page(page);
		put_page(page);

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