I was de-fragmenting a BTRFS recently and it was quite slow, so I decided to pipe find output to xargs -P 2 to speed up the file listing process and found out it breaks BTRFS quite fast. In 2 minutes, I had this in dmesg. As expected, btrfs command is deadlocked.
btrfs-progs v4.2.2 [3650924.735400] ------------[ cut here ]------------ [3650924.735423] WARNING: CPU: 3 PID: 3561 at /home/zumbi/linux-4.3.5/fs/btrfs/locking.c:46 btrfs_set_lock_blocking_rw+0xa2/0xb0 [btrfs]() [3650924.735424] Modules linked in: dccp_diag dccp udp_diag unix_diag ipt_REJECT nf_reject_ipv4 nf_log_ipv6 ip_vs_rr xt_ipvs ip_vs ip6table_filter xt_conntrack xt_multiport xt_limit xt_nat squashfs tcp_diag inet_diag nf_log_ipv4 nf_log_common xt_LOG xt_u32 xt_tcpudp xt_hashlimit xt_recent iptable_filter dm_snapshot dm_bufio veth vhost_net vhost macvtap macvlan tun cbc rbd libceph libcrc32c ip6table_nat nf_conntrack_ipv6 nf_defrag_ipv6 nf_nat_ipv6 binfmt_misc ip6_tables xt_REDIRECT nf_nat_redirect iptable_nat nf_conntrack_ipv4 nf_defrag_ipv4 nf_nat_ipv4 nf_nat nf_conntrack ip_tables x_tables nfsd auth_rpcgss oid_registry nfs_acl nfs lockd grace sunrpc arc4 ecb md4 hmac nls_utf8 cifs dns_resolver fscache nbd bridge bonding btrfs iTCO_wdt iTCO_vendor_support evdev coretemp ttm kvm_intel drm_kms_helper kvm [3650924.735464] drm pcspkr dcdbas i7core_edac i2c_algo_bit edac_core acpi_power_meter 8250_fintek button acpi_cpufreq lpc_ich tpm_tis tpm mfd_core shpchp processor 8021q garp mrp stp llc loop ipmi_watchdog ipmi_si ipmi_poweroff ipmi_devintf ipmi_msghandler fuse parport_pc ppdev lp parport autofs4 ext4 crc16 mbcache jbd2 dm_mod raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq raid1 md_mod sg sd_mod uas usb_storage crc32c_intel mvsas libsas ehci_pci libata ehci_hcd scsi_transport_sas bnx2 usbcore usb_common scsi_mod [3650924.735497] CPU: 3 PID: 3561 Comm: btrfs Tainted: G W 4.3.0-0.bpo.1-amd64 #1 Debian 4.3.5-1~bpo8+1 [3650924.735499] Hardware name: Dell Inc. PowerEdge R310/05XKKK, BIOS 1.5.2 10/15/2010 [3650924.735500] 0000000000000000 00000000b671a633 ffffffff812e1ac9 0000000000000000 [3650924.735502] ffffffff81074451 ffff880039cc3a28 0000000000000000 ffff8800b7528b80 [3650924.735504] ffff880039cc3a28 ffff8801fbe7eae0 ffffffffa0597c22 00000000000001ec [3650924.735507] Call Trace: [3650924.735512] [<ffffffff812e1ac9>] ? dump_stack+0x40/0x57 [3650924.735515] [<ffffffff81074451>] ? warn_slowpath_common+0x81/0xb0 [3650924.735530] [<ffffffffa0597c22>] ? btrfs_set_lock_blocking_rw+0xa2/0xb0 [btrfs] [3650924.735537] [<ffffffffa053620c>] ? btrfs_realloc_node+0xcc/0x490 [btrfs] [3650924.735551] [<ffffffffa0574e2d>] ? btrfs_defrag_leaves+0x1ed/0x360 [btrfs] [3650924.735562] [<ffffffffa055f316>] ? btrfs_defrag_root+0x56/0xe0 [btrfs] [3650924.735576] [<ffffffffa0595446>] ? btrfs_ioctl_defrag+0x126/0x170 [btrfs] [3650924.735590] [<ffffffffa05972e3>] ? btrfs_ioctl+0x1873/0x20f0 [btrfs] [3650924.735593] [<ffffffff812fe069>] ? list_del+0x9/0x20 [3650924.735596] [<ffffffff810b2ff0>] ? remove_wait_queue+0x20/0x30 [3650924.735598] [<ffffffff813b279a>] ? n_tty_write+0x28a/0x4e0 [3650924.735602] [<ffffffff811e3465>] ? do_vfs_ioctl+0x2d5/0x4b0 [3650924.735605] [<ffffffff811d01b3>] ? vfs_write+0x143/0x190 [3650924.735607] [<ffffffff811e36b6>] ? SyS_ioctl+0x76/0x90 [3650924.735611] [<ffffffff8158a9f6>] ? system_call_fast_compare_end+0xc/0x6b [3650924.735612] ---[ end trace 0c5cdef70670d5c5 ]--- [3650924.735628] ------------[ cut here ]------------ [3650924.793031] kernel BUG at /home/zumbi/linux-4.3.5/fs/btrfs/locking.c:295! [3650924.876593] invalid opcode: 0000 [#1] SMP [3650924.927896] Modules linked in: dccp_diag dccp udp_diag unix_diag ipt_REJECT nf_reject_ipv4 nf_log_ipv6 ip_vs_rr xt_ipvs ip_vs ip6table_filter xt_conntrack xt_multiport xt_limit xt_nat squashfs tcp_diag inet_diag nf_log_ipv4 nf_log_common xt_LOG xt_u32 xt_tcpudp xt_hashlimit xt_recent iptable_filter dm_snapshot dm_bufio veth vhost_net vhost macvtap macvlan tun cbc rbd libceph libcrc32c ip6table_nat nf_conntrack_ipv6 nf_defrag_ipv6 nf_nat_ipv6 binfmt_misc ip6_tables xt_REDIRECT nf_nat_redirect iptable_nat nf_conntrack_ipv4 nf_defrag_ipv4 nf_nat_ipv4 nf_nat nf_conntrack ip_tables x_tables nfsd auth_rpcgss oid_registry nfs_acl nfs lockd grace sunrpc arc4 ecb md4 hmac nls_utf8 cifs dns_resolver fscache nbd bridge bonding btrfs iTCO_wdt iTCO_vendor_support evdev coretemp ttm kvm_intel drm_kms_helper kvm [3650925.783705] drm pcspkr dcdbas i7core_edac i2c_algo_bit edac_core acpi_power_meter 8250_fintek button acpi_cpufreq lpc_ich tpm_tis tpm mfd_core shpchp processor 8021q garp mrp stp llc loop ipmi_watchdog ipmi_si ipmi_poweroff ipmi_devintf ipmi_msghandler fuse parport_pc ppdev lp parport autofs4 ext4 crc16 mbcache jbd2 dm_mod raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq raid1 md_mod sg sd_mod uas usb_storage crc32c_intel mvsas libsas ehci_pci libata ehci_hcd scsi_transport_sas bnx2 usbcore usb_common scsi_mod [3650926.350014] CPU: 3 PID: 3561 Comm: btrfs Tainted: G W 4.3.0-0.bpo.1-amd64 #1 Debian 4.3.5-1~bpo8+1 [3650926.473013] Hardware name: Dell Inc. PowerEdge R310/05XKKK, BIOS 1.5.2 10/15/2010 [3650926.564902] task: ffff8800a03acf80 ti: ffff8800242a8000 task.ti: ffff8800242a8000 [3650926.656787] RIP: 0010:[<ffffffffa0597b75>] [<ffffffffa0597b75>] btrfs_assert_tree_locked.part.1+0x5/0x10 [btrfs] [3650926.782049] RSP: 0018:ffff8800242abc28 EFLAGS: 00010246 [3650926.847848] RAX: 0000000000000000 RBX: ffff880039cc3a28 RCX: 0000000000000006 [3650926.935675] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000009 [3650927.023399] RBP: 0000000000000000 R08: 000000000000000a R09: 000000000000fffe [3650927.111125] R10: 0000000000000386 R11: 0000000000000002 R12: ffff8800b7528b80 [3650927.198954] R13: ffff880039cc3a28 R14: ffff8801fbe7eae0 R15: 0000000000000000 [3650927.286679] FS: 00007fdefc02a8c0(0000) GS:ffff88042f260000(0000) knlGS:0000000000000000 [3650927.385850] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b [3650927.457027] CR2: 00007fdefc045000 CR3: 00000002d32e3000 CR4: 00000000000006e0 [3650927.544753] Stack: [3650927.571080] ffffffffa0597c13 00000000000001ec ffffffffa053620c 00000000b671a633 [3650927.662135] 0000000000000002 0000000000000003 00004000000001ec ffff8800b7528b80 [3650927.753291] ffff880039cc3c58 ffff8800b7528800 0000000000000000 ffff8801fbe7eae0 [3650927.844451] Call Trace: [3650927.875790] [<ffffffffa0597c13>] ? btrfs_set_lock_blocking_rw+0x93/0xb0 [btrfs] [3650927.966524] [<ffffffffa053620c>] ? btrfs_realloc_node+0xcc/0x490 [btrfs] [3650928.050090] [<ffffffffa0574e2d>] ? btrfs_defrag_leaves+0x1ed/0x360 [btrfs] [3650928.135629] [<ffffffffa055f316>] ? btrfs_defrag_root+0x56/0xe0 [btrfs] [3650928.217007] [<ffffffffa0595446>] ? btrfs_ioctl_defrag+0x126/0x170 [btrfs] [3650928.301610] [<ffffffffa05972e3>] ? btrfs_ioctl+0x1873/0x20f0 [btrfs] [3650928.381102] [<ffffffff812fe069>] ? list_del+0x9/0x20 [3650928.443851] [<ffffffff810b2ff0>] ? remove_wait_queue+0x20/0x30 [3650928.517007] [<ffffffff813b279a>] ? n_tty_write+0x28a/0x4e0 [3650928.586001] [<ffffffff811e3465>] ? do_vfs_ioctl+0x2d5/0x4b0 [3650928.656138] [<ffffffff811d01b3>] ? vfs_write+0x143/0x190 [3650928.723050] [<ffffffff811e36b6>] ? SyS_ioctl+0x76/0x90 [3650928.787883] [<ffffffff8158a9f6>] ? system_call_fast_compare_end+0xc/0x6b [3650928.871547] Code: ff ff ff e8 6e 65 c5 e0 e9 94 e0 ff ff 66 0f 1f 84 00 00 00 00 00 66 66 66 66 90 0f 0b 66 0f 1f 84 00 00 00 00 00 66 66 66 66 90 <0f> 0b 66 0f 1f 84 00 00 00 00 00 66 66 66 66 90 53 66 83 7f 5c [3650929.107439] RIP [<ffffffffa0597b75>] btrfs_assert_tree_locked.part.1+0x5/0x10 [btrfs] [3650929.204547] RSP <ffff8800242abc28> [3650929.248779] ---[ end trace 0c5cdef70670d5c6 ]--- -- 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
