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        Xin Hao <xhao@linux.alibaba.com>, linux-mm@kvack.org,
        mm-commits@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [RFC][PATCH] cifs: Fix cifs_writepages_region()
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From:   David Howells <dhowells@redhat.com>
Date:   Fri, 24 Feb 2023 14:31:15 +0000
Message-ID: <2213409.1677249075@warthog.procyon.org.uk>
Precedence: bulk

Here's the simplest fix for cifs_writepages_region() that gets it to work.

Fix the cifs_writepages_region() to just skip over members of the batch th=
at
have been cleaned up rather than retrying them.  I'm not entirely sure why=
 it
fixes it, though.  It's also not the most efficient as, in the common case=
,
this is going to happen a lot because cifs_extend_writeback() is going to
clean up the contiguous pages in the batch - and then this skip will occur=
 for
those.

Fix: 3822a7c40997 ("Merge tag 'mm-stable-2023-02-20-13-37' of git://git.ke=
rnel.org/pub/scm/linux/kernel/git/akpm/mm")
Signed-off-by: David Howells <dhowells@redhat.com>
---
diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index 5365a3299088..ebfcaae8c437 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -2893,8 +2893,9 @@ static int cifs_writepages_region(struct address_spa=
ce *mapping,
 =

 			if (folio_mapping(folio) !=3D mapping ||
 			    !folio_test_dirty(folio)) {
+				start +=3D folio_size(folio);
 				folio_unlock(folio);
-				goto skip_write;
+				continue;
 			}
 =

 			if (folio_test_writeback(folio) ||