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From: David Howells <>
Cc: Jeff Layton <>,
	Jeff Layton <>,
	Al Viro <>,
	Matthew Wilcox <>,, Jeff Layton <>,
	"Matthew Wilcox (Oracle)" <>,,
Subject: [PATCH v2 2/3] afs: Fix afs_write_end() to handle short writes
Date: Thu, 17 Jun 2021 09:24:16 +0100	[thread overview]
Message-ID: <> (raw)
In-Reply-To: <>

Fix afs_write_end() to correctly handle a short copy into the intended
write region of the page.  Two things are necessary:

 (1) If the page is not up to date, then we should just return 0
     (ie. indicating a zero-length copy).  The loop in
     generic_perform_write() will go around again, possibly breaking up the
     iterator into discrete chunks.

     This is analogous to commit b9de313cf05fe08fa59efaf19756ec5283af672a
     for ceph.

 (2) The page should not have been set uptodate if it wasn't completely set
     up by netfs_write_begin() (this will be fixed in the next patch), so
     we need to set uptodate here in such a case.

Also remove the assertion that was checking that the page was set uptodate
since it's now set uptodate if it wasn't already a few lines above.  The
assertion was from when uptodate was set elsewhere.

Fixes: 3003bbd0697b ("afs: Use the netfs_write_begin() helper")
Reported-by: Jeff Layton <>
Signed-off-by: David Howells <>
Acked-by: Jeff Layton <>
cc: Al Viro <>
cc: Matthew Wilcox <>
Link: # v1

 fs/afs/write.c |   12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/fs/afs/write.c b/fs/afs/write.c
index 56e2cff2cb87..8a4053ae03dd 100644
--- a/fs/afs/write.c
+++ b/fs/afs/write.c
@@ -119,6 +119,16 @@ int afs_write_end(struct file *file, struct address_space *mapping,
 	       vnode->fid.vid, vnode->fid.vnode, page->index);
+	len = min_t(size_t, len, thp_size(page) - from);
+	if (!PageUptodate(page)) {
+		if (copied < len) {
+			copied = 0;
+			goto out;
+		}
+		SetPageUptodate(page);
+	}
 	if (copied == 0)
 		goto out;
@@ -133,8 +143,6 @@ int afs_write_end(struct file *file, struct address_space *mapping,
-	ASSERT(PageUptodate(page));
 	if (PagePrivate(page)) {
 		priv = page_private(page);
 		f = afs_page_dirty_from(page, priv);

  parent reply	other threads:[~2021-06-17  8:24 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-06-17  8:23 [PATCH v2 0/3] netfs, afs: Fix netfs_write_begin and THP handling David Howells
2021-06-17  8:24 ` [PATCH v2 1/3] afs: Handle len being extending over page end in write_begin/write_end David Howells
2021-06-21 14:32   ` Matthew Wilcox
2021-06-17  8:24 ` David Howells [this message]
2021-06-21 14:36   ` [PATCH v2 2/3] afs: Fix afs_write_end() to handle short writes Matthew Wilcox
2021-06-17  8:24 ` [PATCH v2 3/3] netfs: fix test for whether we can skip read when writing beyond EOF David Howells
2021-06-21 14:50   ` Matthew Wilcox
2021-06-18  3:46 ` [PATCH v2 0/3] netfs, afs: Fix netfs_write_begin and THP handling Al Viro

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