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 93CA02D77FF; Wed, 25 Feb 2026 06:57:08 +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=1772002628; cv=none; b=GGkAcywx0TcW8qfVs1aXrstNS/Y9UdTdfujma3Uv4jTafcIt8N+FToMXuvXTmF3PHmgHNbSiFexdZ90sIznFaxBDBCOsmhYmL0HX0rn+F2YV0glJQbww7nlXk/YKf0ComYwp1TK19mOa5cDr492rpqYxxb+ocxKYSrQc959KR4c= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772002628; c=relaxed/simple; bh=hV3lftL4dOf2KDNb9fpWvaDBbDi0o43Tj+XBN8+/7GU=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=l1QnTLI0GmtfOlxa0kuspWzESvMt9lVSIDtoEj/QeWJG3E5Fi39uQ+ml27wxBNgfym/SBVBtInUIFdkeh0A6CSk9qjbvB+FVQG0ftls4fur9U3+jFKisQQrEDMNWO+n42FW2RHQ9BNOAP+ePmlwNR1qwQrA7qGEqoLkjztZmAjA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=ZNe1MImJ; 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="ZNe1MImJ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6D10AC116D0; Wed, 25 Feb 2026 06:57:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1772002628; bh=hV3lftL4dOf2KDNb9fpWvaDBbDi0o43Tj+XBN8+/7GU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ZNe1MImJRqoeyc4OIIUmQ5s+4hOT+h7zDHlUpJeiD5tCgMaEuq6ZGuTZmKygl1haT ZPaXURyyO9AnQg/kBhfoNB/ShtFsAHEIpmd/rRb2cKOzHwzhFnZu9QFfnglGc215lP crWzKSPrDaP35UTl8xk1xYKWMXUognU+MvFvXdMo= 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 6.18 390/641] pNFS: fix a missing wake up while waiting on NFS_LAYOUT_DRAIN Date: Tue, 24 Feb 2026 17:21:56 -0800 Message-ID: <20260225012358.028144475@linuxfoundation.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260225012348.915798704@linuxfoundation.org> References: <20260225012348.915798704@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 6.18-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 33bc6db0dc92f..b3cb5ee9d821e 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