On 05.10.2010 00:28, Chris Mason wrote: >>> Does it happen with any 32gb file that doesn't compress well? >> >> The 220 GB qcow2 file was basically uncompressible (backuppc archive >> full of bzip2-compressed files). > > Ok, I think I know what is happening here, they all lead to the same > chunk of code. I'll be able to reproduce this locally. FYI, qemu/kvm doesn't seem to like its files located on btrfs mounted with compress-force. I have a filesystem mounted with noatime,compress-force, where I created a 100GB sparse file. There, I wanted to install a Linux distribution - however, the whole qemu-kvm process hanged with these entries being repeated over and over. It's not possible to kill the qemu-kvm process (even with kill -9) etc. [103678.068429] INFO: task qemu-kvm:18722 blocked for more than 120 seconds. [103678.068434] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [103678.068439] qemu-kvm D 00000001062a02ba 0 18722 18607 0x00000000 [103678.068446] ffff88008d80bb38 0000000000000082 ffff880000000000 00000000000148c0 [103678.068453] ffff88008725db00 00000000000148c0 ffff88008d80bfd8 00000000000148c0 [103678.068459] ffff88008d80a000 00000000000148c0 ffff88008725dea8 00000000000148c0 [103678.068466] Call Trace: [103678.068490] [<ffffffffa06a3ee5>] btrfs_start_ordered_extent+0x75/0xc0 [btrfs] [103678.068499] [<ffffffff8107e5e0>] ? autoremove_wake_function+0x0/0x40 [103678.068517] [<ffffffffa06a44a1>] btrfs_wait_ordered_range+0xc1/0x160 [btrfs] [103678.068535] [<ffffffffa0695922>] btrfs_file_aio_write+0x542/0x9a0 [btrfs] [103678.068542] [<ffffffff8108f562>] ? futex_wait_queue_me+0xc2/0x100 [103678.068549] [<ffffffff81082462>] ? hrtimer_cancel+0x22/0x30 [103678.068568] [<ffffffffa06953e0>] ? btrfs_file_aio_write+0x0/0x9a0 [btrfs] [103678.068576] [<ffffffff81144533>] do_sync_readv_writev+0xd3/0x110 [103678.068583] [<ffffffff81091db9>] ? do_futex+0x109/0xb00 [103678.068590] [<ffffffff811d9789>] ? security_file_permission+0x29/0xa0 [103678.068597] [<ffffffff811447f4>] do_readv_writev+0xd4/0x1f0 [103678.068603] [<ffffffff810714ef>] ? kill_pid_info+0x3f/0x60 [103678.068610] [<ffffffff81144958>] vfs_writev+0x48/0x60 [103678.068615] [<ffffffff81144c92>] sys_pwritev+0xa2/0xc0 [103678.068623] [<ffffffff8100af82>] system_call_fastpath+0x16/0x1b -- Tomasz Chmielewski http://wpkg.org -- 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
