afs: Fix to take ref on page when PG_private is set

Fix afs to take a ref on a page when it sets PG_private on it and to drop
the ref when removing the flag.

Note that in afs_write_begin(), a lot of the time, PG_private is already
set on a page to which we're going to add some data.  In such a case, we
leave the bit set and mustn't increment the page count.

As suggested by Matthew Wilcox, use attach/detach_page_private() where
possible.

Fixes: 31143d5d51 ("AFS: implement basic file write support")
Reported-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
This commit is contained in:
David Howells
2020-10-21 13:22:19 +01:00
parent d383e346f9
commit fa04a40b16
4 changed files with 18 additions and 26 deletions

View File

@@ -243,10 +243,8 @@ void afs_edit_dir_add(struct afs_vnode *vnode,
index, gfp);
if (!page)
goto error;
if (!PagePrivate(page)) {
set_page_private(page, 1);
SetPagePrivate(page);
}
if (!PagePrivate(page))
attach_page_private(page, (void *)1);
dir_page = kmap(page);
}