Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Organization: Red Hat UK Ltd. Registered Address: Red Hat UK Ltd, Amberley
        Place, 107-111 Peascod Street, Windsor, Berkshire, SI4 1TE, United
        Kingdom.
        Registered in England and Wales under Company Registration No. 3798903
Subject: [PATCH 1/8] afs: Always include dir in bulk status fetch from
 afs_do_lookup()
From:   David Howells <dhowells@redhat.com>
To:     linux-afs@lists.infradead.org
Cc:     Dave Botsch <botsch@cnf.cornell.edu>,
        Jeffrey Altman <jaltman@auristor.com>,
        linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
        dhowells@redhat.com
Date:   Fri, 24 Apr 2020 16:19:53 +0100
Message-ID: <158774159361.3619859.14445546902173034503.stgit@warthog.procyon.org.uk>
In-Reply-To: <158774158625.3619859.10579201535876583842.stgit@warthog.procyon.org.uk>
References: <158774158625.3619859.10579201535876583842.stgit@warthog.procyon.org.uk>
User-Agent: StGit/0.21
MIME-Version: 1.0
Content-Type: text/plain; charset="utf-8"
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

When a lookup is done in an AFS directory, the filesystem will speculate
and fetch up to 49 other statuses for files in the same directory and fetch
those as well, turning them into inodes or updating inodes that already
exist.

However, occasionally, a callback break might go missing due to NAT timing
out, but the afs filesystem doesn't then realise that the directory is not
up to date.

Alleviate this by using one of the status slots to check the directory in
which the lookup is being done.

Reported-by: Dave Botsch <botsch@cnf.cornell.edu>
Suggested-by: Jeffrey Altman <jaltman@auristor.com>
Signed-off-by: David Howells <dhowells@redhat.com>
---

 fs/afs/dir.c |    9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/fs/afs/dir.c b/fs/afs/dir.c
index d1e1caa23c8b..3c486340b220 100644
--- a/fs/afs/dir.c
+++ b/fs/afs/dir.c
@@ -658,7 +658,8 @@ static struct inode *afs_do_lookup(struct inode *dir, struct dentry *dentry,
 
 	cookie->ctx.actor = afs_lookup_filldir;
 	cookie->name = dentry->d_name;
-	cookie->nr_fids = 1; /* slot 0 is saved for the fid we actually want */
+	cookie->nr_fids = 2; /* slot 0 is saved for the fid we actually want
+			      * and slot 1 for the directory */
 
 	read_seqlock_excl(&dvnode->cb_lock);
 	dcbi = rcu_dereference_protected(dvnode->cb_interest,
@@ -709,7 +710,11 @@ static struct inode *afs_do_lookup(struct inode *dir, struct dentry *dentry,
 	if (!cookie->inodes)
 		goto out_s;
 
-	for (i = 1; i < cookie->nr_fids; i++) {
+	cookie->fids[1] = dvnode->fid;
+	cookie->statuses[1].cb_break = afs_calc_vnode_cb_break(dvnode);
+	cookie->inodes[1] = igrab(&dvnode->vfs_inode);
+
+	for (i = 2; i < cookie->nr_fids; i++) {
 		scb = &cookie->statuses[i];
 
 		/* Find any inodes that already exist and get their