diff mbox series

[v2,42/53] afs: Fix afs_write_end() to handle len > page size

Message ID 163492971302.1038219.3619344566416020631.stgit@warthog.procyon.org.uk (mailing list archive)
State New, archived
Headers show
Series fscache: Rewrite index API and management system | expand

Commit Message

David Howells Oct. 22, 2021, 7:08 p.m. UTC 
It is possible for the len argument to afs_write_end() to overrun the end
of the page (len is used to key the size of the page in afs_write_start()
when compound pages become a regular thing).

Fix afs_write_end() to correctly trim the write length so that it doesn't
exceed the end of the page.

Fixes: 3003bbd0697b ("afs: Use the netfs_write_begin() helper")
Reported-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Jeff Layton <jlayton@kernel.org>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: Al Viro <viro@zeniv.linux.org.uk>
cc: Matthew Wilcox <willy@infradead.org>
cc: linux-afs@lists.infradead.org
Link: https://lore.kernel.org/r/162367682522.460125.5652091227576721609.stgit@warthog.procyon.org.uk/ # v1
---

 fs/afs/write.c |    1 +
 1 file changed, 1 insertion(+)
diff mbox series

Patch

diff --git a/fs/afs/write.c b/fs/afs/write.c
index ced72c6b9a80..19be3153d610 100644
--- a/fs/afs/write.c
+++ b/fs/afs/write.c
@@ -119,6 +119,7 @@  int afs_write_end(struct file *file, struct address_space *mapping,
 	_enter("{%llx:%llu},{%lx}",
 	       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;