From mboxrd@z Thu Jan 1 00:00:00 1970 Delivery-date: Wed, 10 Dec 2025 11:16:43 +0100 Received: from metis.whiteo.stw.pengutronix.de ([2a0a:edc0:2:b01:1d::104]) by lore.white.stw.pengutronix.de with esmtps (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.96) (envelope-from ) id 1vTHFT-009sTb-2l for lore@lore.pengutronix.de; Wed, 10 Dec 2025 11:16:43 +0100 Received: from bombadil.infradead.org ([2607:7c80:54:3::133]) by metis.whiteo.stw.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1vTHFT-0001v2-9v for lore@pengutronix.de; Wed, 10 Dec 2025 11:16:43 +0100 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:To:In-Reply-To:References: Message-Id:Content-Transfer-Encoding:Content-Type:MIME-Version:Subject:Date: From:Reply-To:Cc:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=Lh46gd/lbx7fDcUN5vCbvuhG/bcgbPbZKOTZXGN/RCo=; b=N+316w9plnj5WvZurjNupL6tef M/47L8JhqQ4+pozrvU8bWTcFmBehLHA1hBnrjmOxb1n4qJkS8vnRkg5WcTdpAKFjI0WkzcMLwz3f8 vjtPBohHWGnk2iakrKXbZGqZenQkpykXGlSBghCSlHqYuUiJR4Ul3IoFKDAs+puDv/onAvDfLt1Aj HzTvHIobAiOJrX6xzF1SfEIIqwsrNlGXeV3SwOgEDbVGpN1WCT2Wc0CdUiLBxeMxSqP5ULtXI8Yzh vwFwSrkmf+GMNYNy1lVJJakcra/zyAmktdjoOcmLK2ne02jveO9+FXrIb3JH+uYXUrNaBNtIs1AWT KCejfk6g==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1vTHEw-0000000FJLJ-3Pa9; Wed, 10 Dec 2025 10:16:10 +0000 Received: from metis.whiteo.stw.pengutronix.de ([2a0a:edc0:2:b01:1d::104]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1vTHEq-0000000FJKC-0rcL for barebox@lists.infradead.org; Wed, 10 Dec 2025 10:16:08 +0000 Received: from drehscheibe.grey.stw.pengutronix.de ([2a0a:edc0:0:c01:1d::a2]) by metis.whiteo.stw.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1vTHEm-0001eI-Ru; Wed, 10 Dec 2025 11:16:00 +0100 Received: from dude02.red.stw.pengutronix.de ([2a0a:edc0:0:1101:1d::28]) by drehscheibe.grey.stw.pengutronix.de with esmtps (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.96) (envelope-from ) id 1vTHEm-004wMH-22; Wed, 10 Dec 2025 11:16:00 +0100 Received: from localhost ([::1] helo=dude02.red.stw.pengutronix.de) by dude02.red.stw.pengutronix.de with esmtp (Exim 4.98.2) (envelope-from ) id 1vTHEm-00000004RFo-2JNt; Wed, 10 Dec 2025 11:16:00 +0100 From: Sascha Hauer Date: Wed, 10 Dec 2025 11:16:00 +0100 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20251210-devfs-prep-v1-2-3a2a3aa27eab@pengutronix.de> References: <20251210-devfs-prep-v1-0-3a2a3aa27eab@pengutronix.de> In-Reply-To: <20251210-devfs-prep-v1-0-3a2a3aa27eab@pengutronix.de> To: BAREBOX X-Mailer: b4 0.14.2 X-Developer-Signature: v=1; a=ed25519-sha256; t=1765361760; l=837; i=s.hauer@pengutronix.de; s=20230412; h=from:subject:message-id; bh=2ynZNBWukr/YKNj0hHzvRprQRpY3EQTL7H1trrDvCfQ=; b=lFUu1j/V+MA1wzez4ZU7tI2dkwhNptmOEzT5/LSStvLg6W8c5keMMGcotaiQ9tFMIroAH1crl 8dUZ0aVdLGXB4VyESNLzegUOTmYnwQCYjBPL5dVy/wEoqudjuelb0c7 X-Developer-Key: i=s.hauer@pengutronix.de; a=ed25519; pk=4kuc9ocmECiBJKWxYgqyhtZOHj5AWi7+d0n/UjhkwTg= X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20251210_021604_243976_FD624189 X-CRM114-Status: UNSURE ( 9.00 ) X-CRM114-Notice: Please train this message. X-BeenThere: barebox@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "barebox" X-SA-Exim-Connect-IP: 2607:7c80:54:3::133 X-SA-Exim-Mail-From: barebox-bounces+lore=pengutronix.de@lists.infradead.org X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on metis.whiteo.stw.pengutronix.de X-Spam-Level: X-Spam-Status: No, score=-4.0 required=4.0 tests=AWL,BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_NONE autolearn=unavailable autolearn_force=no version=3.4.2 Subject: [PATCH 2/3] fs: warn when mount reference count becomes negative X-SA-Exim-Version: 4.2.1 (built Wed, 08 May 2019 21:11:16 +0000) X-SA-Exim-Scanned: Yes (on metis.whiteo.stw.pengutronix.de) Warn when the reference count of a mount would become negative. With this we warn when it happens. Previously, only unmounting a mountpoint failed with -EBUSY which was misleading because mnt->ref was only true because it was negative. Do not actually allow it to become negative anymore. Signed-off-by: Sascha Hauer --- fs/fs.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/fs/fs.c b/fs/fs.c index f7859304a7b5f4158db83298b586c633668301d5..e063dc48d9d53a64932564c4b983d5ca1b026a1a 100644 --- a/fs/fs.c +++ b/fs/fs.c @@ -260,6 +260,12 @@ static void mntput(struct vfsmount *mnt) if (!mnt) return; + if (!mnt->ref) { + WARN_ONCE(1, "refcount for mount \"%s\" becomes negative\n", + mnt->mountpoint->name); + return; + } + mnt->ref--; } -- 2.47.3