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 C3BF9629 for ; Wed, 2 Nov 2022 03:22:24 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 37520C433D6; Wed, 2 Nov 2022 03:22:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1667359344; bh=fDrx7TTXpCz0mKQJO3yNsT+ibc3h//sUeoj7ldowWoM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Tw5nLJLrxSFyD1Kj0CMUW4nLTClKWuMcWXEQVEbvVExZtFFuh1GX26wponOqzY3Mu kFW4XfClHwAVWto00ujuSgoeboJICooPpzntxGXgAe3wkXUlS1jZvRXTtKPsazQlgL SnZrChhtb1wiRm+CDv46bixOAkippUjgHlG+xlMw= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, "Darrick J. Wong" , Allison Collins , Chandan Babu R , Christoph Hellwig , Brian Foster , Dave Chinner , "Darrick J. Wong" , Chandan Babu R Subject: [PATCH 5.4 24/64] xfs: clear XFS_DQ_FREEING if we cant lock the dquot buffer to flush Date: Wed, 2 Nov 2022 03:33:50 +0100 Message-Id: <20221102022052.595212086@linuxfoundation.org> X-Mailer: git-send-email 2.38.1 In-Reply-To: <20221102022051.821538553@linuxfoundation.org> References: <20221102022051.821538553@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Chandan Babu R From: "Darrick J. Wong" commit c97738a960a86081a147e7d436138e6481757445 upstream. In commit 8d3d7e2b35ea, we changed xfs_qm_dqpurge to bail out if we can't lock the dquot buf to flush the dquot. This prevents the AIL from blocking on the dquot, but it also forgets to clear the FREEING flag on its way out. A subsequent purge attempt will see the FREEING flag is set and bail out, which leads to dqpurge_all failing to purge all the dquots. (copy-pasting from Dave Chinner's identical patch) This was found by inspection after having xfs/305 hang 1 in ~50 iterations in a quotaoff operation: [ 8872.301115] xfs_quota D13888 92262 91813 0x00004002 [ 8872.302538] Call Trace: [ 8872.303193] __schedule+0x2d2/0x780 [ 8872.304108] ? do_raw_spin_unlock+0x57/0xd0 [ 8872.305198] schedule+0x6e/0xe0 [ 8872.306021] schedule_timeout+0x14d/0x300 [ 8872.307060] ? __next_timer_interrupt+0xe0/0xe0 [ 8872.308231] ? xfs_qm_dqusage_adjust+0x200/0x200 [ 8872.309422] schedule_timeout_uninterruptible+0x2a/0x30 [ 8872.310759] xfs_qm_dquot_walk.isra.0+0x15a/0x1b0 [ 8872.311971] xfs_qm_dqpurge_all+0x7f/0x90 [ 8872.313022] xfs_qm_scall_quotaoff+0x18d/0x2b0 [ 8872.314163] xfs_quota_disable+0x3a/0x60 [ 8872.315179] kernel_quotactl+0x7e2/0x8d0 [ 8872.316196] ? __do_sys_newstat+0x51/0x80 [ 8872.317238] __x64_sys_quotactl+0x1e/0x30 [ 8872.318266] do_syscall_64+0x46/0x90 [ 8872.319193] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [ 8872.320490] RIP: 0033:0x7f46b5490f2a [ 8872.321414] Code: Bad RIP value. Returning -EAGAIN from xfs_qm_dqpurge() without clearing the XFS_DQ_FREEING flag means the xfs_qm_dqpurge_all() code can never free the dquot, and we loop forever waiting for the XFS_DQ_FREEING flag to go away on the dquot that leaked it via -EAGAIN. Fixes: 8d3d7e2b35ea ("xfs: trylock underlying buffer on dquot flush") Signed-off-by: Darrick J. Wong Reviewed-by: Allison Collins Reviewed-by: Chandan Babu R Reviewed-by: Christoph Hellwig Reviewed-by: Brian Foster Signed-off-by: Dave Chinner Reviewed-by: Dave Chinner Acked-by: Darrick J. Wong Signed-off-by: Chandan Babu R Signed-off-by: Greg Kroah-Hartman --- fs/xfs/xfs_qm.c | 1 + 1 file changed, 1 insertion(+) --- a/fs/xfs/xfs_qm.c +++ b/fs/xfs/xfs_qm.c @@ -148,6 +148,7 @@ xfs_qm_dqpurge( error = xfs_bwrite(bp); xfs_buf_relse(bp); } else if (error == -EAGAIN) { + dqp->dq_flags &= ~XFS_DQ_FREEING; goto out_unlock; } xfs_dqflock(dqp);