I can reliably get btrfs 0.19 to hang in btrfs_commit_transaction. Below is another case where it hung after creating just 110 snapshots of /var/log/. Here is an excerpt from the script log file showing the last good snapshot followed by the hang: >>> Dec 12 10:25:23 EST 2010 snapshot /mnt/sdf1/snap000108 /mnt/sdf1/snap000109 Create a snapshot of '/mnt/sdf1/snap000108' in '/mnt/sdf1/snap000109' Filesystem 1K-blocks Used Available Use% Mounted on /dev/sdf1 195359960 133800028 61559932 69% /mnt/sdf1 Data: total=184.28GB, used=127.29GB Metadata: total=1.01GB, used=161.60MB System: total=12.00MB, used=28.00KB >>> Dec 12 10:26:17 EST 2010 snapshot /mnt/sdf1/snap000109 /mnt/sdf1/snap000110 [... HUNG HERE in btrfs subvolume snapshot /mnt/sdf1/snap000109 /mnt/sdf1/snap000110 ...] Here's a small example of what's in kern.log: 2010-12-12T10:28:18.721597-05:00 linux kernel: [31921.122910] INFO: task btrfs-transacti:26891 blocked for more than 120 seconds. 2010-12-12T10:28:18.721642-05:00 linux kernel: [31921.122918] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. 2010-12-12T10:28:18.721656-05:00 linux kernel: [31921.122925] btrfs-transac D 00000001003010a3 0 26891 2 0x00000000 2010-12-12T10:28:18.721667-05:00 linux kernel: [31921.122936] ffff8801b1649d40 0000000000000046 0000000000000000 0000000000015980 2010-12-12T10:28:18.721678-05:00 linux kernel: [31921.122946] ffff8801b1649fd8 0000000000015980 ffff8801b1649fd8 ffff8800833f16e0 2010-12-12T10:28:18.721688-05:00 linux kernel: [31921.122956] 0000000000015980 0000000000015980 ffff8801b1649fd8 0000000000015980 2010-12-12T10:28:18.721696-05:00 linux kernel: [31921.122964] Call Trace: 2010-12-12T10:28:18.721708-05:00 linux kernel: [31921.123001] [<ffffffffa05403a9>] wait_for_commit+0x89/0xf0 [btrfs] 2010-12-12T10:28:18.721718-05:00 linux kernel: [31921.123014] [<ffffffff8107f620>] ? autoremove_wake_function+0x0/0x40 2010-12-12T10:28:18.721728-05:00 linux kernel: [31921.123047] [<ffffffffa0541c20>] btrfs_commit_transaction+0x5f0/0x6f0 [btrfs] 2010-12-12T10:28:18.721738-05:00 linux kernel: [31921.123077] [<ffffffffa054212b>] ? start_transaction+0x1ab/0x230 [btrfs] 2010-12-12T10:28:18.721751-05:00 linux kernel: [31921.123087] [<ffffffff8107f620>] ? autoremove_wake_function+0x0/0x40 2010-12-12T10:28:18.721763-05:00 linux kernel: [31921.123115] [<ffffffffa053bf33>] transaction_kthread+0x283/0x290 [btrfs] 2010-12-12T10:28:18.721774-05:00 linux kernel: [31921.123143] [<ffffffffa053bcb0>] ? transaction_kthread+0x0/0x290 [btrfs] 2010-12-12T10:28:18.721782-05:00 linux kernel: [31921.123152] [<ffffffff8107f0c6>] kthread+0x96/0xa0 2010-12-12T10:28:18.721792-05:00 linux kernel: [31921.123161] [<ffffffff8100aee4>] kernel_thread_helper+0x4/0x10 2010-12-12T10:28:18.721800-05:00 linux kernel: [31921.123169] [<ffffffff8107f030>] ? kthread+0x0/0xa0 2010-12-12T10:28:18.721812-05:00 linux kernel: [31921.123177] [<ffffffff8100aee0>] ? kernel_thread_helper+0x0/0x10 After a reboot we try the fsck: # btrfsck /dev/sdc1 fs tree 5151 refs 110 followed by 110 lines of the form: unresolved ref root NNNN dir 256 index 4898 namelen 10 name snap000001 error 600 where NNNN goes from 5150 to 5259. Then this closing output: found 136841752576 bytes used err is 1 total csum bytes: 133469012 total tree bytes: 169484288 total fs tree bytes: 4497408 btree space waste bytes: 22338098 file data blocks allocated: 149437534208 referenced 149425737728 Btrfs Btrfs v0.19 Command exited with non-zero status 1 The "ps" listing showed the same as in my previous messages. -- | Ian! D. Allen - idallen@xxxxxxxxxx - Ottawa, Ontario, Canada | Home Page: http://idallen.com/ Contact Improv: http://contactimprov.ca/ | College professor (Free/Libre GNU+Linux) at: http://teaching.idallen.com/ | Defend digital freedom: http://eff.org/ and have fun: http://fools.ca/ -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
