From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E415E1EB5E1; Wed, 25 Feb 2026 01:36:11 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1771983372; cv=none; b=F0pP14pXX0hF/p9WBV6yIR305DsaJYz9Swm14RpQ1Xsgmmb5ywKoGjvPPRfyAcC9d7a2ylnHNGpZ3Cy1CbAxPBmjnQZsTMb1XlLuP45c8nnTIRXqGKiLm0Z8QtsBcrvja/gaPsp83Kpe7b9HL3D/r4V40B7RvtVyHMn4X17+BFQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1771983372; c=relaxed/simple; bh=/cJFzM6aRijBpKBOt1K8PtmnyDkb54MlE7zxJYgn+n4=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=NogGrvvSUJ1pIA4nOx1XGCDyb4WEYkqhnHNgL4r8mwCA59rS+QLc0qRn0XSd4U/yEypjBy3KCcGU9aapbJSO6Gtwc1LtzABSFXvFLYujwkDxwWiX5e9lY/+EeA0+EqY1VPAI+5YrhzTpcrUlVr1UV7OTZZxCdFCT3yWFo8nHekg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=19bApyUQ; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="19bApyUQ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A479AC19424; Wed, 25 Feb 2026 01:36:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1771983371; bh=/cJFzM6aRijBpKBOt1K8PtmnyDkb54MlE7zxJYgn+n4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=19bApyUQMwpb1DMDB5c6HbsJjpCJ4m5HqWo1Bm+lsDw8FFmiBm2yjZt76EasjqRmO 5PUiUmpOHqCfZQygRMgGchILEnacbEDpQ+mO1gwEAjygXtAppy7hi+uMcnhmmGXElQ caxbYgpU9l8oVVXfkg0mq/CEFoB7kSTgg5tcTYiI= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Trond Myklebust , Olga Kornievskaia , Anna Schumaker , Sasha Levin Subject: [PATCH 6.19 497/781] pNFS: fix a missing wake up while waiting on NFS_LAYOUT_DRAIN Date: Tue, 24 Feb 2026 17:20:06 -0800 Message-ID: <20260225012411.995709041@linuxfoundation.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260225012359.695468795@linuxfoundation.org> References: <20260225012359.695468795@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.19-stable review patch. If anyone has any objections, please let me know. ------------------ From: Olga Kornievskaia [ Upstream commit 5248d8474e594d156bee1ed10339cc16e207a28b ] It is possible to have a task get stuck on waiting on the NFS_LAYOUT_DRAIN in the following scenario 1. cpu a: waiter test NFS_LAYOUT_DRAIN (1) and plh_outstanding (1) 2. cpu b: atomic_dec_and_test() -> clear bit -> wake up 3. cpu c: sets NFS_LAYOUT_DRAIN again 4. cpu a: calls wait_on_bit() sleeps forever. To expand on this we have say 2 outstanding pnfs write IO that get ESTALE which causes both to call pnfs_destroy_layout() and set the NFS_LAYOUT_DRAIN bit but the 1st one doesn't call the pnfs_put_layout_hdr() yet (as that would prevent the 2nd ESTALE write from trying to call pnfs_destroy_layout()). If the 1st ESTALE write is the one that initially sets the NFS_LAYOUT_DRAIN so that new IO on this file initiates new LAYOUTGET. Another new write would find NFS_LAYOUT_DRAIN set and phl_outstanding>0 (step 1) and would wait_on_bit(). LAYOUTGET completes doing step 2. Now, the 2nd of ESTALE writes is calling pnfs_destory_layout() and set the NFS_LAYOUT_DRAIN bit (step 3). Finally, the waiting write wakes up to check the bit and goes back to sleep. The problem revolves around the fact that if NFS_LAYOUT_INVALID_STID was already set, it should not do the work of pnfs_mark_layout_stateid_invalid(), thus NFS_LAYOUT_DRAIN will not be set more than once for an invalid layout. Suggested-by: Trond Myklebust Fixes: 880265c77ac4 ("pNFS: Avoid a live lock condition in pnfs_update_layout()") Signed-off-by: Olga Kornievskaia Signed-off-by: Anna Schumaker Signed-off-by: Sasha Levin --- fs/nfs/pnfs.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/fs/nfs/pnfs.c b/fs/nfs/pnfs.c index cff225721d1ce..ff8483d3373a8 100644 --- a/fs/nfs/pnfs.c +++ b/fs/nfs/pnfs.c @@ -463,7 +463,8 @@ pnfs_mark_layout_stateid_invalid(struct pnfs_layout_hdr *lo, }; struct pnfs_layout_segment *lseg, *next; - set_bit(NFS_LAYOUT_INVALID_STID, &lo->plh_flags); + if (test_and_set_bit(NFS_LAYOUT_INVALID_STID, &lo->plh_flags)) + return !list_empty(&lo->plh_segs); clear_bit(NFS_INO_LAYOUTCOMMIT, &NFS_I(lo->plh_inode)->flags); list_for_each_entry_safe(lseg, next, &lo->plh_segs, pls_list) pnfs_clear_lseg_state(lseg, lseg_list); -- 2.51.0