From patchwork Thu Nov 7 19:47:11 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Eric Sandeen X-Patchwork-Id: 11233689 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 229CF14E5 for ; Thu, 7 Nov 2019 19:47:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E8CEB2178F for ; Thu, 7 Nov 2019 19:47:17 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="a0Rm3VWu" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726349AbfKGTrR (ORCPT ); Thu, 7 Nov 2019 14:47:17 -0500 Received: from us-smtp-delivery-1.mimecast.com ([207.211.31.120]:22218 "EHLO us-smtp-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1725385AbfKGTrR (ORCPT ); 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Thu, 7 Nov 2019 19:47:12 +0000 (UTC) Received: from [IPv6:::1] (ovpn04.gateway.prod.ext.phx2.redhat.com [10.5.9.4]) by smtp.corp.redhat.com (Postfix) with ESMTPS id C11E360FC2; Thu, 7 Nov 2019 19:47:11 +0000 (UTC) Subject: [PATCH 1/2] fs: avoid softlockups in s_inodes iterators From: Eric Sandeen To: fsdevel Cc: Al Viro References: Autocrypt: addr=sandeen@redhat.com; prefer-encrypt=mutual; keydata= mQINBE6x99QBEADMR+yNFBc1Y5avoUhzI/sdR9ANwznsNpiCtZlaO4pIWvqQJCjBzp96cpCs nQZV32nqJBYnDpBDITBqTa/EF+IrHx8gKq8TaSBLHUq2ju2gJJLfBoL7V3807PQcI18YzkF+ WL05ODFQ2cemDhx5uLghHEeOxuGj+1AI+kh/FCzMedHc6k87Yu2ZuaWF+Gh1W2ix6hikRJmQ vj5BEeAx7xKkyBhzdbNIbbjV/iGi9b26B/dNcyd5w2My2gxMtxaiP7q5b6GM2rsQklHP8FtW ZiYO7jsg/qIppR1C6Zr5jK1GQlMUIclYFeBbKggJ9mSwXJH7MIftilGQ8KDvNuV5AbkronGC sEEHj2khs7GfVv4pmUUHf1MRIvV0x3WJkpmhuZaYg8AdJlyGKgp+TQ7B+wCjNTdVqMI1vDk2 BS6Rg851ay7AypbCPx2w4d8jIkQEgNjACHVDU89PNKAjScK1aTnW+HNUqg9BliCvuX5g4z2j gJBs57loTWAGe2Ve3cMy3VoQ40Wt3yKK0Eno8jfgzgb48wyycINZgnseMRhxc2c8hd51tftK LKhPj4c7uqjnBjrgOVaVBupGUmvLiePlnW56zJZ51BR5igWnILeOJ1ZIcf7KsaHyE6B1mG+X dmYtjDhjf3NAcoBWJuj8euxMB6TcQN2MrSXy5wSKaw40evooGwARAQABtCRFcmljIFIuIFNh bmRlZW4gPHNhbmRlZW5AcmVkaGF0LmNvbT6JAjgEEwECACIFAk6yrl4CGwMGCwkIBwMCBhUI AgkKCwQWAgMBAh4BAheAAAoJECCuFpLhPd7gh2kP/A6CRmIF2MSttebyBk+6Ppx47ct+Kcmp YokwfI9iahSPiQ+LmmBZE+PMYesE+8+lsSiAvzz6YEXsfWMlGzHiqiE76d2xSOYVPO2rX7xl 4T2J98yZlYrjMDmQ6gpFe0ZBpVl45CFUYkBaeulEMspzaYLH6zGsPjgfVJyYnW94ZXLWcrST ixBPJcDtk4j6jrbY3K8eVFimK+RSq6CqZgUZ+uaDA/wJ4kHrYuvM3QPbsHQr/bYSNkVAFxgl G6a4CSJ4w70/dT9FFb7jzj30nmaBmDFcuC+xzecpcflaLvuFayuBJslMp4ebaL8fglvntWsQ ZM8361Ckjt82upo2JRYiTrlE9XiSEGsxW3EpdFT3vUmIlgY0/Xo5PGv3ySwcFucRUk1Q9j+Z X4gCaX5sHpQM03UTaDx4jFdGqOLnTT1hfrMQZ3EizVbnQW9HN0snm9lD5P6O1dxyKbZpevfW BfwdQ35RXBbIKDmmZnwJGJgYl5Bzh5DlT0J7oMVOzdEVYipWx82wBqHVW4I1tPunygrYO+jN n+BLwRCOYRJm5BANwYx0MvWlm3Mt3OkkW2pbX+C3P5oAcxrflaw3HeEBi/KYkygxovWl93IL TsW03R0aNcI6bSdYR/68pL4ELdx7G/SLbaHf28FzzUFjRvN55nBoMePOFo1O6KtkXXQ4GbXV ebdvuQINBE6x99QBEADQOtSJ9OtdDOrE7xqJA4Lmn1PPbk2n9N+m/Wuh87AvxU8Ey8lfg/mX VXbJ3vQxlFRWCOYLJ0TLEsnobZjIc7YhlMRqNRjRSn5vcSs6kulnCG+BZq2OJ+mPpsFIq4Nd 5OGoV2SmEXmQCaB9UAiRqflLFYrf5LRXYX+jGy0hWIGEyEPAjpexGWdUGgsthwSKXEDYWVFR Lsw5kaZEmRG10YPmShVlIzrFVlBKZ8QFphD9YkEYlB0/L3ieeUBWfeUff43ule81S4IZX63h hS3e0txG4ilgEI5aVztumB4KmzldrR0hmAnwui67o4Enm9VeM/FOWQV1PRLT+56sIbnW7ynq wZEudR4BQaRB8hSoZSNbasdpeBY2/M5XqLe1/1hqJcqXdq8Vo1bWQoGzRPkzVyeVZlRS2XqT TiXPk6Og1j0n9sbJXcNKWRuVdEwrzuIthBKtxXpwXP09GXi9bUsZ9/fFFAeeB43l8/HN7xfk 0TeFv5JLDIxISonGFVNclV9BZZbR1DE/sc3CqY5ZgX/qb7WAr9jaBjeMBCexZOu7hFVNkacr AQ+Y4KlJS+xNFexUeCxYnvSp3TI5KNa6K/hvy+YPf5AWDK8IHE8x0/fGzE3l62F4sw6BHBak ufrI0Wr/G2Cz4QKAb6BHvzJdDIDuIKzm0WzY6sypXmO5IwaafSTElQARAQABiQIfBBgBAgAJ BQJOsffUAhsMAAoJECCuFpLhPd7gErAP/Rk46ZQ05kJI4sAyNnHea1i2NiB9Q0qLSSJg+94a hFZOpuKzxSK0+02sbhfGDMs6KNJ04TNDCR04in9CdmEY2ywx6MKeyW4rQZB35GQVVY2ZxBPv yEF4ZycQwBdkqrtuQgrO9zToYWaQxtf+ACXoOI0a/RQ0Bf7kViH65wIllLICnewD738sqPGd N51fRrKBcDquSlfRjQW83/11+bjv4sartYCoE7JhNTcTr/5nvZtmgb9wbsA0vFw+iiUs6tTj eioWcPxDBw3nrLhV8WPf+MMXYxffG7i/Y6OCVWMwRgdMLE/eanF6wYe6o6K38VH6YXQw/0kZ +PrH5uP/0kwG0JbVtj9o94x08ZMm9eMa05VhuUZmtKNdGfn75S7LfoK+RyuO7OJIMb4kR7Eb FzNbA3ias5BaExPknJv7XwI74JbEl8dpheIsRbt0jUDKcviOOfhbQxKJelYNTD5+wE4+TpqH XQLj5HUlzt3JSwqSwx+++FFfWFMheG2HzkfXrvTpud5NrJkGGVn+ErXy6pNf6zSicb+bUXe9 i92UTina2zWaaLEwXspqM338TlFC2JICu8pNt+wHpPCjgy2Ei4u5/4zSYjiA+X1I+V99YJhU +FpT2jzfLUoVsP/6WHWmM/tsS79i50G/PsXYzKOHj/0ZQCKOsJM14NMMCC8gkONe4tek Message-ID: <29aceb8b-5307-c04f-a20b-366be05eb365@redhat.com> Date: Thu, 7 Nov 2019 13:47:11 -0600 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:68.0) Gecko/20100101 Thunderbird/68.2.1 MIME-Version: 1.0 In-Reply-To: Content-Language: en-US X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 X-MC-Unique: c6vEJrMTOsyqIjxokbx96Q-1 X-Mimecast-Spam-Score: 0 Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org Anything that walks all inodes on sb->s_inodes list without rescheduling risks softlockups. Previous efforts were made in 2 functions, see: c27d82f fs/drop_caches.c: avoid softlockups in drop_pagecache_sb() ac05fbb inode: don't softlockup when evicting inodes but there hasn't been an audit of all walkers, so do that now. This also consistently moves the cond_resched() calls to the bottom of each loop in cases where it already exists. One loop remains: remove_dquot_ref(), because I'm not quite sure how to deal with that one w/o taking the i_lock. Signed-off-by: Eric Sandeen Reviewed-by: Jan Kara --- V2: Drop unrelated iput cleanups in fsnotify diff --git a/fs/drop_caches.c b/fs/drop_caches.c index d31b6c72b476..dc1a1d5d825b 100644 --- a/fs/drop_caches.c +++ b/fs/drop_caches.c @@ -35,11 +35,11 @@ static void drop_pagecache_sb(struct super_block *sb, void *unused) spin_unlock(&inode->i_lock); spin_unlock(&sb->s_inode_list_lock); - cond_resched(); invalidate_mapping_pages(inode->i_mapping, 0, -1); iput(toput_inode); toput_inode = inode; + cond_resched(); spin_lock(&sb->s_inode_list_lock); } spin_unlock(&sb->s_inode_list_lock); diff --git a/fs/inode.c b/fs/inode.c index fef457a42882..b0c789bb3dba 100644 --- a/fs/inode.c +++ b/fs/inode.c @@ -676,6 +676,7 @@ int invalidate_inodes(struct super_block *sb, bool kill_dirty) struct inode *inode, *next; LIST_HEAD(dispose); +again: spin_lock(&sb->s_inode_list_lock); list_for_each_entry_safe(inode, next, &sb->s_inodes, i_sb_list) { spin_lock(&inode->i_lock); @@ -698,6 +699,13 @@ int invalidate_inodes(struct super_block *sb, bool kill_dirty) inode_lru_list_del(inode); spin_unlock(&inode->i_lock); list_add(&inode->i_lru, &dispose); + + if (need_resched()) { + spin_unlock(&sb->s_inode_list_lock); + cond_resched(); + dispose_list(&dispose); + goto again; + } } spin_unlock(&sb->s_inode_list_lock); diff --git a/fs/notify/fsnotify.c b/fs/notify/fsnotify.c index 2ecef6155fc0..ac9eb273e28c 100644 --- a/fs/notify/fsnotify.c +++ b/fs/notify/fsnotify.c @@ -77,6 +77,7 @@ static void fsnotify_unmount_inodes(struct super_block *sb) iput_inode = inode; + cond_resched(); spin_lock(&sb->s_inode_list_lock); } spin_unlock(&sb->s_inode_list_lock); diff --git a/fs/quota/dquot.c b/fs/quota/dquot.c index 6e826b454082..4a085b3c7cac 100644 --- a/fs/quota/dquot.c +++ b/fs/quota/dquot.c @@ -985,6 +985,7 @@ static int add_dquot_ref(struct super_block *sb, int type) * later. */ old_inode = inode; + cond_resched(); spin_lock(&sb->s_inode_list_lock); } spin_unlock(&sb->s_inode_list_lock); From patchwork Thu Nov 7 19:48:48 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Eric Sandeen X-Patchwork-Id: 11233691 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 1A98B14E5 for ; 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bh=3YRu9QEU0TNp6qYcGvPetED2Tp+b6pubzp9ni6exZGY=; b=E+9+jemrjGdiWjFKuoJYoL0VjQbYsrrNBBTAu4ynULRCSYPysIACWi9asO6u7Pn5s52O2Q pqo3ZvL5ZJpzvDAvHms2TN9QhPLXCStNHMgrZvJJ3fWUfzm/0jEsM8Jp+FM7PKFXDGLYbQ k+jwU5/wm/arWTsvZsGyJTWEXwIaqAg= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-375-T_z9GNdnOFuM2uo84T_9qA-1; Thu, 07 Nov 2019 14:48:50 -0500 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 2CA0B8017DD; Thu, 7 Nov 2019 19:48:49 +0000 (UTC) Received: from [IPv6:::1] (ovpn04.gateway.prod.ext.phx2.redhat.com [10.5.9.4]) by smtp.corp.redhat.com (Postfix) with ESMTPS id E521619757; Thu, 7 Nov 2019 19:48:48 +0000 (UTC) Subject: [PATCH 2/2] fs: call fsnotify_sb_delete after evict_inodes From: Eric Sandeen To: fsdevel Cc: Al Viro References: Autocrypt: addr=sandeen@redhat.com; prefer-encrypt=mutual; keydata= mQINBE6x99QBEADMR+yNFBc1Y5avoUhzI/sdR9ANwznsNpiCtZlaO4pIWvqQJCjBzp96cpCs nQZV32nqJBYnDpBDITBqTa/EF+IrHx8gKq8TaSBLHUq2ju2gJJLfBoL7V3807PQcI18YzkF+ WL05ODFQ2cemDhx5uLghHEeOxuGj+1AI+kh/FCzMedHc6k87Yu2ZuaWF+Gh1W2ix6hikRJmQ vj5BEeAx7xKkyBhzdbNIbbjV/iGi9b26B/dNcyd5w2My2gxMtxaiP7q5b6GM2rsQklHP8FtW ZiYO7jsg/qIppR1C6Zr5jK1GQlMUIclYFeBbKggJ9mSwXJH7MIftilGQ8KDvNuV5AbkronGC sEEHj2khs7GfVv4pmUUHf1MRIvV0x3WJkpmhuZaYg8AdJlyGKgp+TQ7B+wCjNTdVqMI1vDk2 BS6Rg851ay7AypbCPx2w4d8jIkQEgNjACHVDU89PNKAjScK1aTnW+HNUqg9BliCvuX5g4z2j gJBs57loTWAGe2Ve3cMy3VoQ40Wt3yKK0Eno8jfgzgb48wyycINZgnseMRhxc2c8hd51tftK LKhPj4c7uqjnBjrgOVaVBupGUmvLiePlnW56zJZ51BR5igWnILeOJ1ZIcf7KsaHyE6B1mG+X dmYtjDhjf3NAcoBWJuj8euxMB6TcQN2MrSXy5wSKaw40evooGwARAQABtCRFcmljIFIuIFNh bmRlZW4gPHNhbmRlZW5AcmVkaGF0LmNvbT6JAjgEEwECACIFAk6yrl4CGwMGCwkIBwMCBhUI AgkKCwQWAgMBAh4BAheAAAoJECCuFpLhPd7gh2kP/A6CRmIF2MSttebyBk+6Ppx47ct+Kcmp YokwfI9iahSPiQ+LmmBZE+PMYesE+8+lsSiAvzz6YEXsfWMlGzHiqiE76d2xSOYVPO2rX7xl 4T2J98yZlYrjMDmQ6gpFe0ZBpVl45CFUYkBaeulEMspzaYLH6zGsPjgfVJyYnW94ZXLWcrST ixBPJcDtk4j6jrbY3K8eVFimK+RSq6CqZgUZ+uaDA/wJ4kHrYuvM3QPbsHQr/bYSNkVAFxgl G6a4CSJ4w70/dT9FFb7jzj30nmaBmDFcuC+xzecpcflaLvuFayuBJslMp4ebaL8fglvntWsQ ZM8361Ckjt82upo2JRYiTrlE9XiSEGsxW3EpdFT3vUmIlgY0/Xo5PGv3ySwcFucRUk1Q9j+Z X4gCaX5sHpQM03UTaDx4jFdGqOLnTT1hfrMQZ3EizVbnQW9HN0snm9lD5P6O1dxyKbZpevfW BfwdQ35RXBbIKDmmZnwJGJgYl5Bzh5DlT0J7oMVOzdEVYipWx82wBqHVW4I1tPunygrYO+jN n+BLwRCOYRJm5BANwYx0MvWlm3Mt3OkkW2pbX+C3P5oAcxrflaw3HeEBi/KYkygxovWl93IL TsW03R0aNcI6bSdYR/68pL4ELdx7G/SLbaHf28FzzUFjRvN55nBoMePOFo1O6KtkXXQ4GbXV ebdvuQINBE6x99QBEADQOtSJ9OtdDOrE7xqJA4Lmn1PPbk2n9N+m/Wuh87AvxU8Ey8lfg/mX VXbJ3vQxlFRWCOYLJ0TLEsnobZjIc7YhlMRqNRjRSn5vcSs6kulnCG+BZq2OJ+mPpsFIq4Nd 5OGoV2SmEXmQCaB9UAiRqflLFYrf5LRXYX+jGy0hWIGEyEPAjpexGWdUGgsthwSKXEDYWVFR Lsw5kaZEmRG10YPmShVlIzrFVlBKZ8QFphD9YkEYlB0/L3ieeUBWfeUff43ule81S4IZX63h hS3e0txG4ilgEI5aVztumB4KmzldrR0hmAnwui67o4Enm9VeM/FOWQV1PRLT+56sIbnW7ynq wZEudR4BQaRB8hSoZSNbasdpeBY2/M5XqLe1/1hqJcqXdq8Vo1bWQoGzRPkzVyeVZlRS2XqT TiXPk6Og1j0n9sbJXcNKWRuVdEwrzuIthBKtxXpwXP09GXi9bUsZ9/fFFAeeB43l8/HN7xfk 0TeFv5JLDIxISonGFVNclV9BZZbR1DE/sc3CqY5ZgX/qb7WAr9jaBjeMBCexZOu7hFVNkacr AQ+Y4KlJS+xNFexUeCxYnvSp3TI5KNa6K/hvy+YPf5AWDK8IHE8x0/fGzE3l62F4sw6BHBak ufrI0Wr/G2Cz4QKAb6BHvzJdDIDuIKzm0WzY6sypXmO5IwaafSTElQARAQABiQIfBBgBAgAJ BQJOsffUAhsMAAoJECCuFpLhPd7gErAP/Rk46ZQ05kJI4sAyNnHea1i2NiB9Q0qLSSJg+94a hFZOpuKzxSK0+02sbhfGDMs6KNJ04TNDCR04in9CdmEY2ywx6MKeyW4rQZB35GQVVY2ZxBPv yEF4ZycQwBdkqrtuQgrO9zToYWaQxtf+ACXoOI0a/RQ0Bf7kViH65wIllLICnewD738sqPGd N51fRrKBcDquSlfRjQW83/11+bjv4sartYCoE7JhNTcTr/5nvZtmgb9wbsA0vFw+iiUs6tTj eioWcPxDBw3nrLhV8WPf+MMXYxffG7i/Y6OCVWMwRgdMLE/eanF6wYe6o6K38VH6YXQw/0kZ +PrH5uP/0kwG0JbVtj9o94x08ZMm9eMa05VhuUZmtKNdGfn75S7LfoK+RyuO7OJIMb4kR7Eb FzNbA3ias5BaExPknJv7XwI74JbEl8dpheIsRbt0jUDKcviOOfhbQxKJelYNTD5+wE4+TpqH XQLj5HUlzt3JSwqSwx+++FFfWFMheG2HzkfXrvTpud5NrJkGGVn+ErXy6pNf6zSicb+bUXe9 i92UTina2zWaaLEwXspqM338TlFC2JICu8pNt+wHpPCjgy2Ei4u5/4zSYjiA+X1I+V99YJhU +FpT2jzfLUoVsP/6WHWmM/tsS79i50G/PsXYzKOHj/0ZQCKOsJM14NMMCC8gkONe4tek Message-ID: <541385e5-e186-65b2-e38e-54dfb4c98e47@redhat.com> Date: Thu, 7 Nov 2019 13:48:48 -0600 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:68.0) Gecko/20100101 Thunderbird/68.2.1 MIME-Version: 1.0 In-Reply-To: Content-Language: en-US X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 X-MC-Unique: T_z9GNdnOFuM2uo84T_9qA-1 X-Mimecast-Spam-Score: 0 Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org When a filesystem is unmounted, we currently call fsnotify_sb_delete() before evict_inodes(), which means that fsnotify_unmount_inodes() must iterate over all inodes on the superblock, even though it will only act on inodes with a refcount. This is inefficient and can lead to livelocks as it iterates over many unrefcounted inodes. However, since fsnotify_sb_delete() and evict_inodes() are working on orthogonal sets of inodes (fsnotify_sb_delete() only cares about nonzero refcount, and evict_inodes() only cares about zero refcount), we can swap the order of the calls. The fsnotify call will then have a much smaller list to walk (any refcounted inodes). This should speed things up overall, and avoid livelocks in fsnotify_unmount_inodes(). Signed-off-by: Eric Sandeen Reviewed-by: Jan Kara diff --git a/fs/notify/fsnotify.c b/fs/notify/fsnotify.c index ac9eb273e28c..426f03b6e660 100644 --- a/fs/notify/fsnotify.c +++ b/fs/notify/fsnotify.c @@ -57,6 +57,10 @@ static void fsnotify_unmount_inodes(struct super_block *sb) * doing an __iget/iput with SB_ACTIVE clear would actually * evict all inodes with zero i_count from icache which is * unnecessarily violent and may in fact be illegal to do. + * + * However, we should have been called /after/ evict_inodes + * removed all zero refcount inodes, in any case. Test to + * be sure. */ if (!atomic_read(&inode->i_count)) { spin_unlock(&inode->i_lock); diff --git a/fs/super.c b/fs/super.c index cfadab2cbf35..cd352530eca9 100644 --- a/fs/super.c +++ b/fs/super.c @@ -448,10 +448,12 @@ void generic_shutdown_super(struct super_block *sb) sync_filesystem(sb); sb->s_flags &= ~SB_ACTIVE; - fsnotify_sb_delete(sb); cgroup_writeback_umount(); + /* evict all inodes with zero refcount */ evict_inodes(sb); + /* only nonzero refcount inodes can have marks */ + fsnotify_sb_delete(sb); if (sb->s_dio_done_wq) { destroy_workqueue(sb->s_dio_done_wq);