linux-kernel - [PATCH 4.19 378/639] afs: Fix double inc of vnode->cb

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Date:   Fri, 24 Jan 2020 10:29:08 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, David Howells <dhowells@...hat.com>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH 4.19 378/639] afs: Fix double inc of vnode->cb_break

From: David Howells <dhowells@...hat.com>

[ Upstream commit fd711586bb7d63f257da5eff234e68c446ac35ea ]

When __afs_break_callback() clears the CB_PROMISED flag, it increments
vnode->cb_break to trigger a future refetch of the status and callback -
however it also calls afs_clear_permits(), which also increments
vnode->cb_break.

Fix this by removing the increment from afs_clear_permits().

Whilst we're at it, fix the conditional call to afs_put_permits() as the
function checks to see if the argument is NULL, so the check is redundant.

Fixes: be080a6f43c4 ("afs: Overhaul permit caching");
Signed-off-by: David Howells <dhowells@...hat.com>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 fs/afs/security.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/fs/afs/security.c b/fs/afs/security.c
index 81dfedb7879ff..66042b432baa8 100644
--- a/fs/afs/security.c
+++ b/fs/afs/security.c
@@ -87,11 +87,9 @@ void afs_clear_permits(struct afs_vnode *vnode)
 	permits = rcu_dereference_protected(vnode->permit_cache,
 					    lockdep_is_held(&vnode->lock));
 	RCU_INIT_POINTER(vnode->permit_cache, NULL);
-	vnode->cb_break++;
 	spin_unlock(&vnode->lock);
 
-	if (permits)
-		afs_put_permits(permits);
+	afs_put_permits(permits);
 }
 
 /*
-- 
2.20.1