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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Alexander Aring <aahringo@redhat.com>,
        David Teigland <teigland@redhat.com>
Subject: [PATCH 5.4 022/255] fs: dlm: handle -EBUSY first in lock arg validation
Date:   Mon, 24 Oct 2022 13:28:52 +0200
Message-Id: <20221024113003.179425329@linuxfoundation.org>
In-Reply-To: <20221024113002.471093005@linuxfoundation.org>
References: <20221024113002.471093005@linuxfoundation.org>
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From: Alexander Aring <aahringo@redhat.com>

commit 44637ca41d551d409a481117b07fa209b330fca9 upstream.

During lock arg validation, first check for -EBUSY cases, then for
-EINVAL cases. The -EINVAL checks look at lkb state variables
which are not stable when an lkb is busy and would cause an
-EBUSY result, e.g. lkb->lkb_grmode.

Cc: stable@vger.kernel.org
Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 fs/dlm/lock.c |   16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

--- a/fs/dlm/lock.c
+++ b/fs/dlm/lock.c
@@ -2888,24 +2888,24 @@ static int set_unlock_args(uint32_t flag
 static int validate_lock_args(struct dlm_ls *ls, struct dlm_lkb *lkb,
 			      struct dlm_args *args)
 {
-	int rv = -EINVAL;
+	int rv = -EBUSY;
 
 	if (args->flags & DLM_LKF_CONVERT) {
-		if (lkb->lkb_flags & DLM_IFL_MSTCPY)
+		if (lkb->lkb_status != DLM_LKSTS_GRANTED)
 			goto out;
 
-		if (args->flags & DLM_LKF_QUECVT &&
-		    !__quecvt_compat_matrix[lkb->lkb_grmode+1][args->mode+1])
+		if (lkb->lkb_wait_type)
 			goto out;
 
-		rv = -EBUSY;
-		if (lkb->lkb_status != DLM_LKSTS_GRANTED)
+		if (is_overlap(lkb))
 			goto out;
 
-		if (lkb->lkb_wait_type)
+		rv = -EINVAL;
+		if (lkb->lkb_flags & DLM_IFL_MSTCPY)
 			goto out;
 
-		if (is_overlap(lkb))
+		if (args->flags & DLM_LKF_QUECVT &&
+		    !__quecvt_compat_matrix[lkb->lkb_grmode+1][args->mode+1])
 			goto out;
 	}