Patch "afs: Fix afs_kill_pages()" has been added to the 4.4-stable tree

Patch "afs: Fix afs_kill_pages()" has been added to the 4.4-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    afs: Fix afs_kill_pages()

to the 4.4-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     afs-fix-afs_kill_pages.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From foo@baz Mon Dec 18 14:47:43 CET 2017
From: David Howells <dhowells@redhat.com>
Date: Thu, 16 Mar 2017 16:27:48 +0000
Subject: afs: Fix afs_kill_pages()

From: David Howells <dhowells@redhat.com>


[ Upstream commit 7286a35e893176169b09715096a4aca557e2ccd2 ]

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>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 fs/afs/write.c |   10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

--- a/fs/afs/write.c
+++ b/fs/afs/write.c
@@ -299,10 +299,14 @@ static void afs_kill_pages(struct afs_vn
 		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);


Patches currently in stable-queue which might be from dhowells@redhat.com are

queue-4.4/afs-flush-outstanding-writes-when-an-fd-is-closed.patch
queue-4.4/afs-fix-the-maths-in-afs_fs_store_data.patch
queue-4.4/afs-populate-group-id-from-vnode-status.patch
queue-4.4/afs-prevent-callback-expiry-timer-overflow.patch
queue-4.4/keys-add-missing-permission-check-for-request_key-destination.patch
queue-4.4/afs-adjust-mode-bits-processing.patch
queue-4.4/afs-fix-page-leak-in-afs_write_begin.patch
queue-4.4/afs-fix-missing-put_page.patch
queue-4.4/afs-migrate-vlocation-fields-to-64-bit.patch
queue-4.4/afs-populate-and-use-client-modification-time.patch
queue-4.4/afs-fix-afs_kill_pages.patch