Commit 43388b21 authored Sep 05, 2016 by Al Viro

fix gfs2_stuffed_write_end() on short copies



a) the page is uptodate - ->write_begin() would either fail (in which
case we don't reach ->write_end()), or unstuff the inode, or find the
page already uptodate, or do a successful call of stuffed_readpage(),
which would've made it uptodate

b) zeroing the tail in pagecache is wrong.  kill -9 at the right time
while writing unmodified file contents to the same file should _not_
leave us in a situation when read() from the file will be reporting
it full of zeroes.  Especially since that effect will be transient -
at some later point the page will be evicted and then we'll be back
to the real file contents.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

parent b9de313c

fs/gfs2/aops.c

+1 −3

Original line number	Diff line number	Diff line
		@@ -839,12 +839,10 @@ static int gfs2_stuffed_write_end(struct inode inode, struct buffer_head dibh,
		BUG_ON((pos + len) > (dibh->b_size - sizeof(struct gfs2_dinode)));
		kaddr = kmap_atomic(page);
		memcpy(buf + pos, kaddr + pos, copied);
		memset(kaddr + pos + copied, 0, len - copied);
		flush_dcache_page(page);
		kunmap_atomic(kaddr);

		if (!PageUptodate(page))
		SetPageUptodate(page);
		WARN_ON(!PageUptodate(page));
		unlock_page(page);
		put_page(page);