Hi, Sasà Vita Thanks for reporting!
> -----Original Message----- > From: linux-btrfs-ow...@vger.kernel.org > [mailto:linux-btrfs-ow...@vger.kernel.org] On Behalf Of Sasà Vita > Sent: Wednesday, July 22, 2015 1:52 PM > To: linux-btrfs@vger.kernel.org > Subject: stack trace (free_fs_root) with either fallocate + > mv-across-subvolumes, or mount-wth-compress + dd > > The script below generates a stack trace, and some of the "mv dir/f dir/a" > commands that it spawns fail with the message: "Device or resource busy". > > The stack trace is not generated on every iteration. The "for" loop ensures > that > it is generated at least once. > > Reproduced on Arch Linux, with various kernels from 3.11.2-1-ARCH up to > 4.0.4-2-ARCH. > > > mkdir dir > truncate -s 3G loop > > fun1() { > mount loop dir > btrfs subvolume create dir/a > fallocate -l 46M dir/f > mv dir/f dir/a > } > > for i in {1..30} ; do > mkfs.btrfs loop > fun1 > umount dir > done > > I tested this script in following platforms, but can't reproduce this bug: 1: physical machine, RHEL7.1, linux 4.2-rc1 2: physical machine, RHEL7.1, linux 4.0 3: physical machine, RHEL7.1, linux 3.11 4: kvm, RHEL6, linux 4.2-rc2 on both physical and loop device, and 3 times(90 loops) tests. Who can test it in other platform? Thanks Zhaolei > [ 112.060072] BTRFS: device fsid 88f9e1b0-d018-4f21-9598-22987aa2b893 > devid 1 transid 4 /dev/loop3 > [ 112.067593] BTRFS info (device loop3): disk space caching is enabled > [ 112.067597] BTRFS: has skinny extents [ 112.067599] BTRFS: flagging fs > with big metadata feature [ 112.068900] BTRFS: creating UUID tree > [ 112.316740] ------------[ cut here ]------------ [ 112.316740] WARNING: > CPU: 0 > PID: 1094 at fs/btrfs/disk-io.c:3549 > free_fs_root+0xe1/0xf0 [btrfs]() > [ 112.316740] Modules linked in: crc32c_generic btrfs xor raid6_pq > cfg80211 rfkill ppdev psmouse snd_intel8x0 iosf_mbi joydev mousedev pcspkr > snd_ac97_codec ac97_bus snd_pcm serio_raw i2c_piix4 i2c_core snd_timer > snd soundcore parport_pc parport battery ac evdev mac_hid acpi_cpufreq > processor sch_fq_codel nfs lockd grace sunrpc fscache > ext4 crc16 mbcache jbd2 dm_snapshot dm_bufio dm_mod squashfs loop isofs > sr_mod cdrom hid_generic usbhid hid atkbd libps2 ahci libahci ohci_pci > ohci_hcd > ehci_pci ehci_hcd libata scsi_mod usbcore usb_common > e1000 intel_agp intel_gtt i8042 serio video button [ 112.316740] CPU: 0 PID: > 1094 Comm: umount Not tainted 4.0.4-2-ARCH #1 [ 112.316740] Hardware > name: innotek GmbH VirtualBox/VirtualBox, BIOS VirtualBox 12/01/2006 > [ 112.316740] 0000000000000000 000000001675626b ffff88004925bc88 > ffffffff81574b23 > [ 112.316740] 0000000000000000 0000000000000000 ffff88004925bcc8 > ffffffff81074dda [ 112.316740] ffff88004925bcd8 ffff880000082000 > ffff880053082000 > ffff880053082068 > [ 112.316740] Call Trace: > [ 112.316740] [<ffffffff81574b23>] dump_stack+0x4c/0x6e [ 112.316740] > [<ffffffff81074dda>] warn_slowpath_common+0x8a/0xc0 [ 112.316740] > [<ffffffff81074f0a>] warn_slowpath_null+0x1a/0x20 [ 112.316740] > [<ffffffffa04f2bc1>] free_fs_root+0xe1/0xf0 [btrfs] [ 112.316740] > [<ffffffffa04f55bd>] > btrfs_drop_and_free_fs_root+0x7d/0xc0 [btrfs] [ 112.316740] > [<ffffffffa04f56df>] btrfs_free_fs_roots+0xdf/0x180 [btrfs] [ 112.316740] > [<ffffffffa04f7471>] close_ctree+0x151/0x360 [btrfs] [ 112.316740] > [<ffffffff811f535d>] ? evict_inodes+0x13d/0x160 [ 112.316740] > [<ffffffffa04ca739>] btrfs_put_super+0x19/0x20 [btrfs] [ 112.316740] > [<ffffffff811da836>] generic_shutdown_super+0x76/0x100 [ 112.316740] > [<ffffffff811dab76>] kill_anon_super+0x16/0x30 [ 112.316740] > [<ffffffffa04ca398>] btrfs_kill_super+0x18/0x120 [btrfs] [ 112.316740] > [<ffffffff811daf69>] deactivate_locked_super+0x49/0x80 [ 112.316740] > [<ffffffff811db3dc>] deactivate_super+0x6c/0x80 [ 112.316740] > [<ffffffff811f8df3>] cleanup_mnt+0x43/0xa0 [ 112.316740] > [<ffffffff811f8ea2>] __cleanup_mnt+0x12/0x20 [ 112.316740] > [<ffffffff810917b4>] task_work_run+0xd4/0xf0 [ 112.316740] > [<ffffffff81015d35>] do_notify_resume+0x75/0x80 [ 112.316740] > [<ffffffff8157a6a3>] int_signal+0x12/0x17 [ 112.316740] ---[ end trace > 1cd8909b794df110 ]--- [ 112.351293] VFS: Busy inodes after unmount of loop3. > Self-destruct in 5 seconds. Have a nice day... > > > I tested a variant of the script, where only the fallocate line is changed, > and > replaced with: > dd if=/dev/zero of=dir/f bs=512 count=1 > I was unable to reproduce the problem, in this case. > > > A related issue: in the following script, some of the 'mv dir/a/f dir' > commands > enter the state D and hang, even if no external storage is involved and the > loop-mounted file is on a tmpfs. > > for i in {1..30} ; do > mkfs.btrfs loop > fun1 > umount dir > mount loop dir > mv dir/a/f dir # this may hang > umount dir > done > > > Furthermore, the following script also generates the same stack trace, as > above. > > mkdir dir > truncate -s 3G loop > > fun2() { > mount -ocompress=zlib loop dir # or compress=lzo > dd if=/usr/bin/js of=dir/a bs=1024 count=2000 } > > for i in {1..30} ; do > mkfs.btrfs loop > fun2 > umount dir > done > > > Hope this helps. > -- > To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the > body > of a message to majord...@vger.kernel.org More majordomo info at > http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
