linux-kernel - [PATCH 2/6] afs: Fix file locking

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Message-ID: <159171919967.3038039.17802563446058952615.stgit@warthog.procyon.org.uk>
Date:   Tue, 09 Jun 2020 17:13:19 +0100
From:   David Howells <dhowells@...hat.com>
To:     linux-afs@...ts.infradead.org
Cc:     Dave Botsch <botsch@....cornell.edu>,
        Dave Botsch <botsch@....cornell.edu>, dhowells@...hat.com,
        linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH 2/6] afs: Fix file locking

Fix AFS file locking to use the correct vnode pointer and remove a member
of the afs_operation struct that is never set, but it is read and followed,
causing an oops.

This can be triggered by:

	flock -s /afs/example.com/foo sleep 1

when it calls the kernel to get a file lock.

Fixes: e49c7b2f6de7 ("afs: Build an abstraction around an "operation" concept")
Reported-by: Dave Botsch <botsch@....cornell.edu>
Signed-off-by: David Howells <dhowells@...hat.com>
Tested-by: Dave Botsch <botsch@....cornell.edu>
---

 fs/afs/flock.c    |    2 +-
 fs/afs/internal.h |    1 -
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/fs/afs/flock.c b/fs/afs/flock.c
index 70e518f7bc19..71eea2a908c7 100644
--- a/fs/afs/flock.c
+++ b/fs/afs/flock.c
@@ -71,7 +71,7 @@ static void afs_schedule_lock_extension(struct afs_vnode *vnode)
 void afs_lock_op_done(struct afs_call *call)
 {
 	struct afs_operation *op = call->op;
-	struct afs_vnode *vnode = op->lock.lvnode;
+	struct afs_vnode *vnode = op->file[0].vnode;
 
 	if (call->error == 0) {
 		spin_lock(&vnode->lock);
diff --git a/fs/afs/internal.h b/fs/afs/internal.h
index e1621b0670cc..519ffb104616 100644
--- a/fs/afs/internal.h
+++ b/fs/afs/internal.h
@@ -795,7 +795,6 @@ struct afs_operation {
 			struct afs_read *req;
 		} fetch;
 		struct {
-			struct afs_vnode *lvnode;	/* vnode being locked */
 			afs_lock_type_t type;
 		} lock;
 		struct {