I'm currently running kernel 3.13.3 with Chris's for-linus merged in (up to commit 93de4ba86480a9e0d1062cb1d535fa97fb81af48). After about a day of heavy IO I'll start to see the following in my kernel log: [22223.454967] INFO: task qemu-system-x86:27673 blocked for more than 120 seconds. [22223.454970] Not tainted 3.13.3-2-dzk #1 [22223.454972] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [22223.454974] qemu-system-x86 D ffff8804039d7800 0 27673 1 0x00000000 [22223.454978] ffff8800d1d6bda0 0000000000000082 ffff8800096aec00 ffff8800d1d6bfd8 [22223.454983] 0000000000014440 0000000000014440 ffff8800096aec00 ffffffffa04aafa0 [22223.454988] 000000000000018b ffff8802e8870000 0000000000003000 0000000000001000 [22223.454993] Call Trace: [22223.455015] [<ffffffffa04aafa0>] ? btrfs_set_token_64+0x60/0xf0 [btrfs] [22223.455036] [<ffffffffa04ae8fb>] ? release_extent_buffer+0x2b/0xd0 [btrfs] [22223.455041] [<ffffffff8151d429>] schedule+0x29/0x70 [22223.455061] [<ffffffffa04ce282>] wait_log_commit.isra.18+0x102/0x130 [btrfs] [22223.455066] [<ffffffff810a2bf0>] ? __wake_up_sync+0x20/0x20 [22223.455085] [<ffffffffa04d1465>] btrfs_sync_log+0x3e5/0x6b0 [btrfs] [22223.455091] [<ffffffff811ba0a0>] ? dput+0x20/0x100 [22223.455112] [<ffffffffa04a4681>] btrfs_sync_file+0x2c1/0x2f0 [btrfs] [22223.455117] [<ffffffff811d2541>] do_fsync+0x51/0x80 [22223.455122] [<ffffffff811d2823>] SyS_fdatasync+0x13/0x20 [22223.455127] [<ffffffff81528d6d>] system_call_fastpath+0x1a/0x1f During this time, all IO totally freezes. Atop reports no disk activity, while my desktop is totally hung. After a few minutes everything comes back to life, only to freeze again after a few more minutes. A reboot clears everything up for a day or so but the problem invariably comes back. Can anybody shed some light on this? PS, the above qemu process is accessing image files on a btrfs volume. These files were created as such: touch winxp.img chattr +C winxp.img fallocate -l20G winxp.img I'm actually quite pleased with VM performance on top of btrfs (until the above problem starts occurring). -- -=[dave]=- Entropy isn't what it used to be. -- 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
