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Mon, 31 Aug 2020 05:07:59 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 49320B62F; Mon, 31 Aug 2020 09:08:31 +0000 (UTC) Subject: Re: [PATCH 01/11] btrfs: initialize sysfs devid and device link for seed device To: Anand Jain , linux-btrfs@vger.kernel.org Cc: dsterba@suse.com, josef@toxicpanda.com References: <2db650ec206db1cb3e68590951b59e222fb10116.1598792561.git.anand.jain@oracle.com> From: Nikolay Borisov Autocrypt: addr=nborisov@suse.com; prefer-encrypt=mutual; keydata= xsFNBFiKBz4BEADNHZmqwhuN6EAzXj9SpPpH/nSSP8YgfwoOqwrP+JR4pIqRK0AWWeWCSwmZ T7g+RbfPFlmQp+EwFWOtABXlKC54zgSf+uulGwx5JAUFVUIRBmnHOYi/lUiE0yhpnb1KCA7f u/W+DkwGerXqhhe9TvQoGwgCKNfzFPZoM+gZrm+kWv03QLUCr210n4cwaCPJ0Nr9Z3c582xc bCUVbsjt7BN0CFa2BByulrx5xD9sDAYIqfLCcZetAqsTRGxM7LD0kh5WlKzOeAXj5r8DOrU2 GdZS33uKZI/kZJZVytSmZpswDsKhnGzRN1BANGP8sC+WD4eRXajOmNh2HL4P+meO1TlM3GLl EQd2shHFY0qjEo7wxKZI1RyZZ5AgJnSmehrPCyuIyVY210CbMaIKHUIsTqRgY5GaNME24w7h TyyVCy2qAM8fLJ4Vw5bycM/u5xfWm7gyTb9V1TkZ3o1MTrEsrcqFiRrBY94Rs0oQkZvunqia c+NprYSaOG1Cta14o94eMH271Kka/reEwSZkC7T+o9hZ4zi2CcLcY0DXj0qdId7vUKSJjEep c++s8ncFekh1MPhkOgNj8pk17OAESanmDwksmzh1j12lgA5lTFPrJeRNu6/isC2zyZhTwMWs k3LkcTa8ZXxh0RfWAqgx/ogKPk4ZxOXQEZetkEyTFghbRH2BIwARAQABzSJOaWtvbGF5IEJv cmlzb3YgPG5ib3Jpc292QHN1c2UuZGU+wsF4BBMBAgAiBQJYijkSAhsDBgsJCAcDAgYVCAIJ CgsEFgIDAQIeAQIXgAAKCRBxvoJG5T8oV/B6D/9a8EcRPdHg8uLEPywuJR8URwXzkofT5bZE IfGF0Z+Lt2ADe+nLOXrwKsamhweUFAvwEUxxnndovRLPOpWerTOAl47lxad08080jXnGfYFS Dc+ew7C3SFI4tFFHln8Y22Q9075saZ2yQS1ywJy+TFPADIprAZXnPbbbNbGtJLoq0LTiESnD w/SUC6sfikYwGRS94Dc9qO4nWyEvBK3Ql8NkoY0Sjky3B0vL572Gq0ytILDDGYuZVo4alUs8 LeXS5ukoZIw1QYXVstDJQnYjFxYgoQ5uGVi4t7FsFM/6ykYDzbIPNOx49Rbh9W4uKsLVhTzG BDTzdvX4ARl9La2kCQIjjWRg+XGuBM5rxT/NaTS78PXjhqWNYlGc5OhO0l8e5DIS2tXwYMDY LuHYNkkpMFksBslldvNttSNei7xr5VwjVqW4vASk2Aak5AleXZS+xIq2FADPS/XSgIaepyTV tkfnyreep1pk09cjfXY4A7qpEFwazCRZg9LLvYVc2M2eFQHDMtXsH59nOMstXx2OtNMcx5p8 0a5FHXE/HoXz3p9bD0uIUq6p04VYOHsMasHqHPbsMAq9V2OCytJQPWwe46bBjYZCOwG0+x58 fBFreP/NiJNeTQPOa6FoxLOLXMuVtpbcXIqKQDoEte9aMpoj9L24f60G4q+pL/54ql2VRscK d87BTQRYigc+ARAAyJSq9EFk28++SLfg791xOh28tLI6Yr8wwEOvM3wKeTfTZd+caVb9gBBy wxYhIopKlK1zq2YP7ZjTP1aPJGoWvcQZ8fVFdK/1nW+Z8/NTjaOx1mfrrtTGtFxVBdSCgqBB jHTnlDYV1R5plJqK+ggEP1a0mr/rpQ9dFGvgf/5jkVpRnH6BY0aYFPprRL8ZCcdv2DeeicOO YMobD5g7g/poQzHLLeT0+y1qiLIFefNABLN06Lf0GBZC5l8hCM3Rpb4ObyQ4B9PmL/KTn2FV Xq/c0scGMdXD2QeWLePC+yLMhf1fZby1vVJ59pXGq+o7XXfYA7xX0JsTUNxVPx/MgK8aLjYW hX+TRA4bCr4uYt/S3ThDRywSX6Hr1lyp4FJBwgyb8iv42it8KvoeOsHqVbuCIGRCXqGGiaeX Wa0M/oxN1vJjMSIEVzBAPi16tztL/wQtFHJtZAdCnuzFAz8ue6GzvsyBj97pzkBVacwp3/Mw qbiu7sDz7yB0d7J2tFBJYNpVt/Lce6nQhrvon0VqiWeMHxgtQ4k92Eja9u80JDaKnHDdjdwq FUikZirB28UiLPQV6PvCckgIiukmz/5ctAfKpyYRGfez+JbAGl6iCvHYt/wAZ7Oqe/3Cirs5 KhaXBcMmJR1qo8QH8eYZ+qhFE3bSPH446+5oEw8A9v5oonKV7zMAEQEAAcLBXwQYAQIACQUC WIoHPgIbDAAKCRBxvoJG5T8oV1pyD/4zdXdOL0lhkSIjJWGqz7Idvo0wjVHSSQCbOwZDWNTN JBTP0BUxHpPu/Z8gRNNP9/k6i63T4eL1xjy4umTwJaej1X15H8Hsh+zakADyWHadbjcUXCkg OJK4NsfqhMuaIYIHbToi9K5pAKnV953xTrK6oYVyd/Rmkmb+wgsbYQJ0Ur1Ficwhp6qU1CaJ mJwFjaWaVgUERoxcejL4ruds66LM9Z1Qqgoer62ZneID6ovmzpCWbi2sfbz98+kW46aA/w8r 7sulgs1KXWhBSv5aWqKU8C4twKjlV2XsztUUsyrjHFj91j31pnHRklBgXHTD/pSRsN0UvM26 lPs0g3ryVlG5wiZ9+JbI3sKMfbdfdOeLxtL25ujs443rw1s/PVghphoeadVAKMPINeRCgoJH zZV/2Z/myWPRWWl/79amy/9MfxffZqO9rfugRBORY0ywPHLDdo9Kmzoxoxp9w3uTrTLZaT9M KIuxEcV8wcVjr+Wr9zRl06waOCkgrQbTPp631hToxo+4rA1jiQF2M80HAet65ytBVR2pFGZF zGYYLqiG+mpUZ+FPjxk9kpkRYz61mTLSY7tuFljExfJWMGfgSg1OxfLV631jV1TcdUnx+h3l Sqs2vMhAVt14zT8mpIuu2VNxcontxgVr1kzYA/tQg32fVRbGr449j1gw57BV9i0vww== Message-ID: Date: Mon, 31 Aug 2020 12:07:55 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <2db650ec206db1cb3e68590951b59e222fb10116.1598792561.git.anand.jain@oracle.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org On 30.08.20 г. 17:40 ч., Anand Jain wrote: > The following test case leads to null kobject-being-freed error. > > mount seed /mnt > add sprout to /mnt > umount /mnt > mount sprout to /mnt > delete seed > > kobject: '(null)' (00000000dd2b87e4): is not initialized, yet kobject_put() is being called. > WARNING: CPU: 1 PID: 15784 at lib/kobject.c:736 kobject_put+0x80/0x350 > RIP: 0010:kobject_put+0x80/0x350 > :: > Call Trace: > btrfs_sysfs_remove_devices_dir+0x6e/0x160 [btrfs] > btrfs_rm_device.cold+0xa8/0x298 [btrfs] > btrfs_ioctl+0x206c/0x22a0 [btrfs] > ksys_ioctl+0xe2/0x140 > __x64_sys_ioctl+0x1e/0x29 > do_syscall_64+0x96/0x150 > entry_SYSCALL_64_after_hwframe+0x44/0xa9 > RIP: 0033:0x7f4047c6288b > :: > > This is because, at the end of the seed device-delete, we try to remove > the seed's devid sysfs entry. But for the seed devices under the sprout > fs, we don't initialize the devid kobject yet. So this patch initializes > the seed device devid kobject and the device link in the sysfs. This takes > care of the Warning. > > Signed-off-by: Anand Jain This patch is doing too many things at once. Split it so that: 1. You first add the new functions add_device/remove_device in 2 separate patches. 2. Switch btrfs_sysfs_add_devices_dir/btrfs_sysfs_remove_devices_dir to ousing the newly added helpers, again in 2 separate patches > --- > fs/btrfs/sysfs.c | 146 ++++++++++++++++++++++++++++++----------------- > 1 file changed, 93 insertions(+), 53 deletions(-) > > diff --git a/fs/btrfs/sysfs.c b/fs/btrfs/sysfs.c > index 190e59152be5..9b5e58091fae 100644 > --- a/fs/btrfs/sysfs.c > +++ b/fs/btrfs/sysfs.c > @@ -1149,45 +1149,48 @@ int btrfs_sysfs_add_space_info_type(struct btrfs_fs_info *fs_info, > return 0; > } > > -/* when one_device is NULL, it removes all device links */ > - > -int btrfs_sysfs_remove_devices_dir(struct btrfs_fs_devices *fs_devices, > - struct btrfs_device *one_device) > +static void btrfs_sysfs_remove_device(struct btrfs_device *device) > { > struct hd_struct *disk; > struct kobject *disk_kobj; > + struct kobject *devices_kobj; > > - if (!fs_devices->devices_kobj) > - return -EINVAL; > + /* > + * Seed fs_devices devices_kobj aren't used, fetch kobject from the > + * fs_info::fs_devices. > + */ > + devices_kobj = device->fs_info->fs_devices->devices_kobj; > + ASSERT(devices_kobj); > > - if (one_device) { > - if (one_device->bdev) { > - disk = one_device->bdev->bd_part; > - disk_kobj = &part_to_dev(disk)->kobj; > - sysfs_remove_link(fs_devices->devices_kobj, > - disk_kobj->name); > - } > + if (device->bdev) { > + disk = device->bdev->bd_part; > + disk_kobj = &part_to_dev(disk)->kobj; > + sysfs_remove_link(devices_kobj, disk_kobj->name); > + } > > - kobject_del(&one_device->devid_kobj); > - kobject_put(&one_device->devid_kobj); > + kobject_del(&device->devid_kobj); > + kobject_put(&device->devid_kobj); > > - wait_for_completion(&one_device->kobj_unregister); > + wait_for_completion(&device->kobj_unregister); > +} > > +/* when 2nd argument device is NULL, it removes all devices link */ > +int btrfs_sysfs_remove_devices_dir(struct btrfs_fs_devices *fs_devices, > + struct btrfs_device *device) > +{ > + struct btrfs_fs_devices *seed_fs_devices; > + > + if (device) { > + btrfs_sysfs_remove_device(device); > return 0; > } > > - list_for_each_entry(one_device, &fs_devices->devices, dev_list) { > - > - if (one_device->bdev) { > - disk = one_device->bdev->bd_part; > - disk_kobj = &part_to_dev(disk)->kobj; > - sysfs_remove_link(fs_devices->devices_kobj, > - disk_kobj->name); > - } > - kobject_del(&one_device->devid_kobj); > - kobject_put(&one_device->devid_kobj); > + list_for_each_entry(device, &fs_devices->devices, dev_list) > + btrfs_sysfs_remove_device(device); > > - wait_for_completion(&one_device->kobj_unregister); > + list_for_each_entry(seed_fs_devices, &fs_devices->seed_list, seed_list) { > + list_for_each_entry(device, &seed_fs_devices->devices, dev_list) > + btrfs_sysfs_remove_device(device); > } > > return 0; > @@ -1271,44 +1274,81 @@ static struct kobj_type devid_ktype = { > .release = btrfs_release_devid_kobj, > }; > > +static int btrfs_sysfs_add_device(struct btrfs_device *device) > +{ > + int ret; > + struct kobject *devices_kobj; > + struct kobject *devinfo_kobj; > + > + /* > + * make sure we use the fs_info::fs_devices to fetch the kobjects > + * even for the seed fs_devices > + */ > + devices_kobj = device->fs_devices->fs_info->fs_devices->devices_kobj; > + devinfo_kobj = device->fs_devices->fs_info->fs_devices->devinfo_kobj; > + ASSERT(devices_kobj); > + ASSERT(devinfo_kobj); > + > + if (device->bdev) { > + struct hd_struct *disk; > + struct kobject *disk_kobj; > + > + disk = device->bdev->bd_part; > + disk_kobj = &part_to_dev(disk)->kobj; > + > + ret = sysfs_create_link(devices_kobj, disk_kobj, > + disk_kobj->name); > + if (ret) { > + btrfs_warn(device->fs_info, > + "sysfs create device link failed %d devid %llu", > + ret, device->devid); > + return ret; > + } > + } > + > + init_completion(&device->kobj_unregister); > + ret = kobject_init_and_add(&device->devid_kobj, &devid_ktype, > + devinfo_kobj, "%llu", device->devid); > + if (ret) { > + kobject_put(&device->devid_kobj); > + btrfs_warn(device->fs_info, > + "sysfs devinfo init failed %d devid %llu", > + ret, device->devid); > + } > + > + return ret; > +} > + > int btrfs_sysfs_add_devices_dir(struct btrfs_fs_devices *fs_devices, > - struct btrfs_device *one_device) > + struct btrfs_device *device) > { > - int error = 0; > - struct btrfs_device *dev; > + int ret = 0; > unsigned int nofs_flag; > + struct btrfs_fs_devices *seed_fs_devices; > > nofs_flag = memalloc_nofs_save(); > - list_for_each_entry(dev, &fs_devices->devices, dev_list) { > > - if (one_device && one_device != dev) > - continue; > + if (device) > + return btrfs_sysfs_add_device(device); > > - if (dev->bdev) { > - struct hd_struct *disk; > - struct kobject *disk_kobj; > - > - disk = dev->bdev->bd_part; > - disk_kobj = &part_to_dev(disk)->kobj; > - > - error = sysfs_create_link(fs_devices->devices_kobj, > - disk_kobj, disk_kobj->name); > - if (error) > - break; > - } > + list_for_each_entry(device, &fs_devices->devices, dev_list) { > + ret = btrfs_sysfs_add_device(device); > + if (ret) > + goto out; > + } > > - init_completion(&dev->kobj_unregister); > - error = kobject_init_and_add(&dev->devid_kobj, &devid_ktype, > - fs_devices->devinfo_kobj, "%llu", > - dev->devid); > - if (error) { > - kobject_put(&dev->devid_kobj); > - break; > + list_for_each_entry(seed_fs_devices, &fs_devices->seed_list, seed_list) { > + list_for_each_entry(device, &seed_fs_devices->devices, dev_list) { > + ret = btrfs_sysfs_add_device(device); > + if (ret) > + goto out; > } > } > + > +out: > memalloc_nofs_restore(nofs_flag); > > - return error; > + return ret; > } > > void btrfs_kobject_uevent(struct block_device *bdev, enum kobject_action action) >