afs: Fix non-setting of mtime when writing into mmap

[ Upstream commit bb413489288e4e457353bac513fddb6330d245ca ]

The mtime on an inode needs to be updated when a write is made into an
mmap'ed section.  There are three ways in which this could be done: update
it when page_mkwrite is called, update it when a page is changed from dirty
to writeback or leave it to the server and fix the mtime up from the reply
to the StoreData RPC.

Found with the generic/215 xfstest.

Fixes: 1cf7a1518aef ("afs: Implement shared-writeable mmap")
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/fs/afs/write.c b/fs/afs/write.c
index cb76566..371db86 100644 (file)
--- a/fs/afs/write.c
+++ b/fs/afs/write.c
@@ -811,6 +811,7 @@ vm_fault_t afs_page_mkwrite(struct vm_fault *vmf)
                             vmf->page->index, priv);
        SetPagePrivate(vmf->page);
        set_page_private(vmf->page, priv);
+       file_update_time(file);
 
        sb_end_pagefault(inode->i_sb);
        return VM_FAULT_LOCKED;