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 452992BAE2 for ; Wed, 17 Apr 2024 21:33:15 +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=1713389596; cv=none; b=YL/iaU3QlMvbWnpS+RPWDjJMmT7GlD8SLrtDIwK1KpMt/3f7xFMeCxrkp6PBR42mHW20OBJordjypa44YTJ+PEdjUGXuNqU3gHj29axj9MoZnouHmuufKXN+FF5/uJsBPDVLMLhguNiK9L14Z9Bg0ZSOdPap7VF/CMv6UYdFNX0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1713389596; c=relaxed/simple; bh=FhEHCc9YvqYdW9CUrjdLLQZsSBpy8JyTDaU2+CEg9LA=; h=Date:Subject:From:To:Cc:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=KvgAJsLdTJr0I00rSs2JKIxVEzyoGFNiAlN+Wk6iCEozU76s80nrDxlg4muglsr7EDkA9hTQpsp6dbEhN2JYswFtb+56Q8OF7MeYtS02x5aVx7RnG830/e/dHQs/t8wuKSHef9IGTRfGP9OnD2h9bg0BvyJk+iHR+1XiHSBjDOs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=eSyDDMbe; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="eSyDDMbe" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C2842C072AA; Wed, 17 Apr 2024 21:33:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1713389595; bh=FhEHCc9YvqYdW9CUrjdLLQZsSBpy8JyTDaU2+CEg9LA=; h=Date:Subject:From:To:Cc:In-Reply-To:References:From; b=eSyDDMbe8z/RgCp72h5MZvAMl+XmEcGZ4rr8tyzlkKpgfi4/VI2AOC92jTLodtb6E H5dBSYk8kze5noWZcHjrJOcPTHA2AsmuF0LEEn9JFEnqIVwKFiYLDbX76ZjUKo7kPH WbVNrXn+54ij1uLCTC2UrS5sFvhn3ydRnBigu0wDhmjn0u4vQpUWTauYx9QXtPoJLV Tw67nJlXffQmEjS0lF3LNF43yO6Bn2XKOg0bzF7TgTKoGcIObmxpTn6a/zylcpRiwm zDT1HVukrCKkKBN000QLXqMA1dFKx3UYqwO0orlboW2dOlZQMve7CwEQ/gsckb4A6E 1+ugmQNu+lTTQ== Date: Wed, 17 Apr 2024 14:33:15 -0700 Subject: [PATCH 44/67] xfs: add lock protection when remove perag from radix tree From: "Darrick J. Wong" To: cem@kernel.org, djwong@kernel.org Cc: Long Li , Christoph Hellwig , Chandan Babu R , Bill O'Donnell , linux-xfs@vger.kernel.org Message-ID: <171338843000.1853449.7497594288174839094.stgit@frogsfrogsfrogs> In-Reply-To: <171338842269.1853449.4066376212453408283.stgit@frogsfrogsfrogs> References: <171338842269.1853449.4066376212453408283.stgit@frogsfrogsfrogs> User-Agent: StGit/0.19 Precedence: bulk X-Mailing-List: linux-xfs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit From: Long Li Source kernel commit: 07afd3173d0c6d24a47441839a835955ec6cf0d4 Take mp->m_perag_lock for deletions from the perag radix tree in xfs_initialize_perag to prevent racing with tagging operations. Lookups are fine - they are RCU protected so already deal with the tree changing shape underneath the lookup - but tagging operations require the tree to be stable while the tags are propagated back up to the root. Right now there's nothing stopping radix tree tagging from operating while a growfs operation is progress and adding/removing new entries into the radix tree. Hence we can have traversals that require a stable tree occurring at the same time we are removing unused entries from the radix tree which causes the shape of the tree to change. Likely this hasn't caused a problem in the past because we are only doing append addition and removal so the active AG part of the tree is not changing shape, but that doesn't mean it is safe. Just making the radix tree modifications serialise against each other is obviously correct. Signed-off-by: Long Li Reviewed-by: Christoph Hellwig Reviewed-by: "Darrick J. Wong" Signed-off-by: Chandan Babu R Reviewed-by: Bill O'Donnell --- libxfs/xfs_ag.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/libxfs/xfs_ag.c b/libxfs/xfs_ag.c index bdb8a08bb..1dbc01b97 100644 --- a/libxfs/xfs_ag.c +++ b/libxfs/xfs_ag.c @@ -422,13 +422,17 @@ xfs_initialize_perag( out_remove_pag: xfs_defer_drain_free(&pag->pag_intents_drain); + spin_lock(&mp->m_perag_lock); radix_tree_delete(&mp->m_perag_tree, index); + spin_unlock(&mp->m_perag_lock); out_free_pag: kmem_free(pag); out_unwind_new_pags: /* unwind any prior newly initialized pags */ for (index = first_initialised; index < agcount; index++) { + spin_lock(&mp->m_perag_lock); pag = radix_tree_delete(&mp->m_perag_tree, index); + spin_unlock(&mp->m_perag_lock); if (!pag) break; xfs_buf_hash_destroy(pag);