From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jan Kara Subject: Re: Dirtiable inode bdi default != sb bdi btrfs Date: Tue, 28 Sep 2010 00:25:48 +0200 Message-ID: <20100927222548.GG3610@quack.suse.cz> References: <4C9AA546.6050201@cesarb.net> <20100923123849.8975fe47.akpm@linux-foundation.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Andrew Morton , linux-kernel@vger.kernel.org, Jan Kara , Jens Axboe , Chris Mason , linux-btrfs@vger.kernel.org, Alexander Viro , linux-fsdevel@vger.kernel.org, stable@kernel.org, Jens Axboe , =?utf-8?Q?Micha=C5=82?= Piotrowski , Chuck Ebbert , kernel@lists.fedoraproject.org To: Cesar Eduardo Barros Return-path: In-Reply-To: <20100923123849.8975fe47.akpm@linux-foundation.org> List-ID: [Added CCs for similar ecryptfs warning] On Thu 23-09-10 12:38:49, Andrew Morton wrote: > > This started appearing for me on v2.6.36-rc5-49-gc79bd89; it did not > > happen on v2.6.36-rc5-33-g1ce1e41, probably because it does not have > > commit 692ebd17c2905313fff3c504c249c6a0faad16ec which introduces the > > warning. > > [...] > > device fsid 44d595920ddedfa-3ece6b56e80f689e devid 1 transid 22342 > > /dev/mapper/vg_cesarbinspiro-lv_home > > SELinux: initialized (dev dm-3, type btrfs), uses xattr > > ------------[ cut here ]------------ > > WARNING: at fs/fs-writeback.c:87 inode_to_bdi+0x62/0x6d() > > Hardware name: Inspiron N4010 > > Dirtiable inode bdi default != sb bdi btrfs > > Modules linked in: ipv6 kvm_intel kvm uinput arc4 ecb > > snd_hda_codec_intelhdmi snd_hda_codec_realtek iwlagn snd_hda_intel > > iwlcore snd_hda_codec uvcvideo snd_hwdep mac80211 videodev snd_seq > > snd_seq_device v4l1_compat snd_pcm atl1c v4l2_compat_ioctl32 btusb > > cfg80211 snd_timer i2c_i801 bluetooth iTCO_wdt dell_wmi dell_laptop snd > > pcspkr wmi dcdbas shpchp iTCO_vendor_support soundcore snd_page_alloc > > rfkill joydev microcode btrfs zlib_deflate libcrc32c cryptd aes_x86_64 > > aes_generic xts gf128mul dm_crypt usb_storage i915 drm_kms_helper drm > > i2c_algo_bit i2c_core video output [last unloaded: scsi_wait_scan] > > Pid: 1073, comm: find Not tainted 2.6.36-rc5+ #8 > > Call Trace: > > [] warn_slowpath_common+0x85/0x9d > > [] warn_slowpath_fmt+0x46/0x48 > > [] inode_to_bdi+0x62/0x6d > > [] __mark_inode_dirty+0xd0/0x177 > > [] touch_atime+0x107/0x12a > > [] ? filldir+0x0/0xd0 > > [] vfs_readdir+0x8d/0xb4 > > [] sys_getdents+0x81/0xd1 > > [] system_call_fastpath+0x16/0x1b Thanks for the report. These bdi pointers are a mess. As Chris pointed out, btrfs forgets to properly initialize inode->i_mapping.backing_dev_info for directories and special inodes and thus these were previously attached to default_backing_dev_info which probably isn't what Chris would like to see. I've also got a similar report for ecryptfs which also does not initialize inode->i_mapping.backing_dev_info although it sets sb->s_bdi and thus again its inodes get filed to default_backing_dev_info lists. Quick search seems to reveal that other filesystems using handcrafted bdi's get it wrong as well and thus their inodes end up in the default_backing_dev_info lists which is generally undesirable (this was happening already before my patch, my code just started complaining about that). That suggests that we should probably handle such cases in a more generic way by changing the code in inode_init_always(). The patch below makes at least btrfs happy for me... Could you maybe test it? Thanks. Honza -- Jan Kara SUSE Labs, CR --- >>From 29f60c2b08ff9637a10439d1513805835ddcc746 Mon Sep 17 00:00:00 2001 From: Jan Kara Date: Mon, 27 Sep 2010 23:56:48 +0200 Subject: [PATCH] bdi: Initialize inode->i_mapping.backing_dev_info to sb->s_bdi Currently, we initialize inode->i_mapping.backing_dev_info to the bdi of device sb->s_bdev points to. However there is quite a big number of filesystems that do not set sb->s_bdev (because they do not have one) but do set sb->s_bdi. These filesystems would generally benefit from setting inode->i_mapping.backing_dev_info to their s_bdi because otherwise their inodes would point to default_backing_dev_info and thus dirty inode tracking would happen there. So change inode initialization code to use sb->s_bdi if it is available. Signed-off-by: Jan Kara --- fs/inode.c | 22 ++++++++++++++-------- 1 files changed, 14 insertions(+), 8 deletions(-) diff --git a/fs/inode.c b/fs/inode.c index 8646433..e415be4 100644 --- a/fs/inode.c +++ b/fs/inode.c @@ -172,15 +172,21 @@ int inode_init_always(struct super_block *sb, struct inode *inode) mapping->writeback_index = 0; /* - * If the block_device provides a backing_dev_info for client - * inodes then use that. Otherwise the inode share the bdev's - * backing_dev_info. + * If the filesystem provides a backing_dev_info for client inodes + * then use that. Otherwise inodes share default_backing_dev_info. */ - if (sb->s_bdev) { - struct backing_dev_info *bdi; - - bdi = sb->s_bdev->bd_inode->i_mapping->backing_dev_info; - mapping->backing_dev_info = bdi; + if (sb->s_bdi && sb->s_bdi != &noop_backing_dev_info) { + /* + * Catch cases where filesystem might be bitten by using s_bdi + * instead of sb->s_bdev. Can be removed in 2.6.38. + */ + if (sb->s_bdev) { + struct backing_dev_info *bdi = + sb->s_bdev->bd_inode->i_mapping->backing_dev_info; + WARN(bdi != sb->s_bdi, "s_bdev bdi %s != s_bdi %s\n", + bdi->name, sb->s_bdi->name); + } + mapping->backing_dev_info = sb->s_bdi; } inode->i_private = NULL; inode->i_mapping = mapping; -- 1.6.4.2