Commit 7286a35e authored Mar 16, 2017 by David Howells

afs: Fix afs_kill_pages()



Fix afs_kill_pages() in two ways:

 (1) If a writeback has been partially flushed, then if we try and kill the
     pages it contains, some of them may no longer be undergoing writeback
     and end_page_writeback() will assert.

     Fix this by checking to see whether the page in question is actually
     undergoing writeback before ending that writeback.

 (2) The loop that scans for pages to kill doesn't increase the first page
     index, and so the loop may not terminate, but it will try to process
     the same pages over and over again.

     Fix this by increasing the first page index to one after the last page
     we processed.

Signed-off-by: David Howells <dhowells@redhat.com>

parent 6d06b0d2

fs/afs/write.c

+7 −3

Original line number	Diff line number	Diff line
		@@ -321,10 +321,14 @@ static void afs_kill_pages(struct afs_vnode *vnode, bool error,
		ASSERTCMP(pv.nr, ==, count);

		for (loop = 0; loop < count; loop++) {
		ClearPageUptodate(pv.pages[loop]);
		struct page *page = pv.pages[loop];
		ClearPageUptodate(page);
		if (error)
		SetPageError(pv.pages[loop]);
		end_page_writeback(pv.pages[loop]);
		SetPageError(page);
		if (PageWriteback(page))
		end_page_writeback(page);
		if (page->index >= first)
		first = page->index + 1;
		}

		__pagevec_release(&pv);

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