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[1].
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.
Changes:
v3: Remove the handling of len exceeding the end of the page.
Fixes: 3003bbd0697b ("afs: Use the netfs_write_begin() helper")
Reported-by: Jeff Layton <[email protected]>
Signed-off-by: David Howells <[email protected]>
Acked-by: Jeff Layton <[email protected]>
cc: Al Viro <[email protected]>
cc: Matthew Wilcox <[email protected]>
cc: [email protected]
Link: https://lore.kernel.org/r/[email protected]/ [1]
Link:
https://lore.kernel.org/r/162367682522.460125.5652091227576721609.st...@warthog.procyon.org.uk/
# v1
Link:
https://lore.kernel.org/r/162391825688.1173366.3437507255136307904.st...@warthog.procyon.org.uk/
# v2
---
fs/afs/write.c | 11 +++++++++--
1 file changed, 9 insertions(+), 2 deletions(-)
diff --git a/fs/afs/write.c b/fs/afs/write.c
index a523bb86915d..641c54679399 100644
--- a/fs/afs/write.c
+++ b/fs/afs/write.c
@@ -118,6 +118,15 @@ int afs_write_end(struct file *file, struct address_space
*mapping,
_enter("{%llx:%llu},{%lx}",
vnode->fid.vid, vnode->fid.vnode, page->index);
+ if (!PageUptodate(page)) {
+ if (copied < len) {
+ copied = 0;
+ goto out;
+ }
+
+ SetPageUptodate(page);
+ }
+
if (copied == 0)
goto out;
@@ -132,8 +141,6 @@ int afs_write_end(struct file *file, struct address_space
*mapping,
write_sequnlock(&vnode->cb_lock);
}
- ASSERT(PageUptodate(page));
-
if (PagePrivate(page)) {
priv = page_private(page);
f = afs_page_dirty_from(page, priv);
--
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