Hi all, I've been trying to test bcache, but I'm running into some kernel oopses that might be of interest. I'm running a 32-bit build of the kernel in the linux-bache git repo on my machine (not using virtualisation) and I'm doing the following simple test*: I have two logical partitions in my hard drive (/dev/sda6 and /dev/sda7), and I'm trying to use sda6 as a cache device for sda7 (backing device). These are the steps that I take: mkfs -t ext4 /dev/sda6 mkfs -t ext4 /dev/sda7 /usr/sbin/make-bcache -C -w2k -b512k /dev/sda6 /usr/sbin/make-bcache -B /dev/sda7 echo /dev/sda6 > /sys/fs/bcache/register echo /dev/sda7 > /sys/fs/bcache/register echo CACHE_SET_UUID > /sys/block/sda/sda7/bcache/attach dev=`cat /sys/block/bcache0/dev | sed -e 's/:/ /'` mknod -m 0660 /dev/test b $dev mkfs -t ext4 /dev/test mount /dev/test /media/bcache So, after that last step, I should be able to have a writethrough cache device (/dev/sda6) attached to a backing device (/dev/sda7) mounted at /media/bcache, right? However, a simple direct write to /media/bcache: dd if=/dev/urandom of=/media/bcache/tmp bs=16k count=500 oflag=direct has the following result ---------------- START OF BUG REPORT --------------------------- May 14 12:49:07 dimension7 kernel: [ 2519.267614] kernel BUG at fs/direct-io.c:647! May 14 12:49:07 dimension7 kernel: [ 2519.267686] invalid opcode: 0000 [#1] SMP May 14 12:49:07 dimension7 kernel: [ 2519.267762] Modules linked in: iwlwifi ext4 jbd2 acpi_cpufreq mperf cpufreq_stats cpufreq_powersave cpufreq_conservative cpufreq_userspace ebtable_nat ebtables ip6table_filter ip6_tables iptable_filter ip_tables x_tables parport_pc ppdev lp parport cryptd aes_i586 aes_generic bnep rfcomm binfmt_misc uinput fuse nfsd nfs nfs_acl auth_rpcgss fscache lockd sunrpc loop snd_hda_codec_hdmi snd_hda_codec_realtek snd_hda_intel snd_hda_codec i915 snd_hwdep snd_pcm drm_kms_helper joydev snd_page_alloc drm snd_seq arc4 snd_seq_device snd_timer evdev btusb battery snd psmouse i2c_algo_bit uvcvideo mac80211 videodev soundcore cfg80211 bluetooth media i2c_i801 rfkill i2c_core iTCO_wdt iTCO_vendor_support ac power_supply serio_raw processor pcspkr button video crc16 ext3 mbcache jbd btrfs crc32c libcrc32c zlib_deflate dm_mod sd_mod crc_t10dif sr_mod cdrom fan thermal thermal_sys ahci libahci libata ehci_hcd r8169 mii scsi_mod usbcore usb_common [last unloaded: iwlwifi] May 14 12:49:07 dimension7 kernel: [ 2519.269498] May 14 12:49:07 dimension7 kernel: [ 2519.269528] Pid: 3123, comm: dd Not tainted 3.2.14-apyrgio-bcache-12.2+ #1 SAMSUNG ELECTRONICS CO., LTD. 300E4A/300E5A/300E7A/3430EA/3530EA/300E4A/300E5A/300E7A/3430EA/3530EA May 14 12:49:07 dimension7 kernel: [ 2519.269777] EIP: 0060:[<c10eec74>] EFLAGS: 00010246 CPU: 0 May 14 12:49:07 dimension7 kernel: [ 2519.269872] EIP is at dio_new_bio.isra.6+0x8e/0xfb May 14 12:49:07 dimension7 kernel: [ 2519.269948] EAX: 00000000 EBX: e4849c78 ECX: e4849d00 EDX: 00000000 May 14 12:49:07 dimension7 kernel: [ 2519.270044] ESI: 00000004 EDI: e4849c78 EBP: f6d54e40 ESP: e4849bc4 May 14 12:49:07 dimension7 kernel: [ 2519.270141] DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068 May 14 12:49:07 dimension7 kernel: [ 2519.270228] Process dd (pid: 3123, ti=e4848000 task=f0c2c670 task.ti=e4848000) May 14 12:49:07 dimension7 kernel: [ 2519.270337] Stack: May 14 12:49:07 dimension7 kernel: [ 2519.270370] 0000000c e4849c78 f6d54e40 e4849d00 f6d54e40 c10eed8f 00008600 00000000 May 14 12:49:07 dimension7 kernel: [ 2519.270528] e4849d1c e4849c78 00001000 00000000 c10eee90 f6185760 f618b720 00008601 May 14 12:49:07 dimension7 kernel: [ 2519.270683] 00000000 00000001 00000004 00000000 f6d54e40 c10ef7bb 00000000 00001000 May 14 12:49:07 dimension7 kernel: [ 2519.270838] Call Trace: May 14 12:49:07 dimension7 kernel: [ 2519.270887] [<c10eed8f>] ? dio_send_cur_page+0x5f/0xa9 May 14 12:49:07 dimension7 kernel: [ 2519.270971] [<c10eee90>] ? submit_page_section+0xb7/0x121 May 14 12:49:07 dimension7 kernel: [ 2519.271061] [<c10ef7bb>] ? __blockdev_direct_IO+0x787/0xa58 May 14 12:49:07 dimension7 kernel: [ 2519.271169] [<f95377e4>] ? noalloc_get_block_write+0x30/0x30 [ext4] May 14 12:49:07 dimension7 kernel: [ 2519.271287] [<f955eb19>] ? ext4_ind_direct_IO+0x214/0x341 [ext4] May 14 12:49:07 dimension7 kernel: [ 2519.271392] [<f95377e4>] ? noalloc_get_block_write+0x30/0x30 [ext4] May 14 12:49:07 dimension7 kernel: [ 2519.271503] [<f953588d>] ? ext4_direct_IO+0x1e8/0x242 [ext4] May 14 12:49:07 dimension7 kernel: [ 2519.271596] [<c10968c7>] ? generic_file_direct_write+0xde/0x164 May 14 12:49:07 dimension7 kernel: [ 2519.271692] [<c1096ac0>] ? __generic_file_aio_write+0x173/0x282 May 14 12:49:07 dimension7 kernel: [ 2519.271788] [<c107b6a0>] ? rcu_enter_nohz+0xc/0x55 May 14 12:49:07 dimension7 kernel: [ 2519.271868] [<c1024bcd>] ? arch_flush_lazy_mmu_mode+0x5/0x14 May 14 12:49:07 dimension7 kernel: [ 2519.271958] [<c1096c2c>] ? generic_file_aio_write+0x5d/0xb3 May 14 12:49:07 dimension7 kernel: [ 2519.272058] [<f9532afa>] ? ext4_file_write+0x1f4/0x242 [ext4] May 14 12:49:07 dimension7 kernel: [ 2519.272151] [<c10cb985>] ? wait_on_retry_sync_kiocb+0x3c/0x3c May 14 12:49:07 dimension7 kernel: [ 2519.272241] [<c10cba25>] ? do_sync_write+0xa0/0xd4 May 14 12:49:07 dimension7 kernel: [ 2519.272321] [<c102a3d0>] ? should_resched+0x5/0x1e May 14 12:49:07 dimension7 kernel: [ 2519.272402] [<c12d5ff1>] ? _cond_resched+0x5/0x18 May 14 12:49:07 dimension7 kernel: [ 2519.272479] [<c10cbf37>] ? rw_verify_area+0xc6/0xe7drivers/scsi/scsi_lib.c May 14 12:49:07 dimension7 kernel: [ 2519.272557] [<c10cc1d7>] ? vfs_write+0x83/0xd4 May 14 12:49:07 dimension7 kernel: [ 2519.272629] [<c10cc397>] ? sys_write+0x3d/0x61 May 14 12:49:07 dimension7 kernel: [ 2519.272704] [<c12db7df>] ? sysenter_do_call+0x12/0x28 May 14 12:49:07 dimension7 kernel: [ 2519.272783] Code: 8b 43 04 8b 54 24 20 8b 73 10 89 04 24 8b 02 e8 62 d1 ff ff 81 fe 00 01 00 00 ba 00 01 00 00 0f 4e d6 39 c2 0f 4f d0 85 d2 7f 02 <0f> 0b 8b 44 24 20 8b 38 b8 d0 00 00 00 e8 b8 de ff ff 8b 0c 24 May 14 12:49:07 dimension7 kernel: [ 2519.273357] EIP: [<c10eec74>]drivers/scsi/scsi_lib.c dio_new_bio.isra.6+0x8e/0xfb SS:ESP 0068:e4849bc4 May 14 12:49:07 dimension7 kernel: [ 2519.331754] ---[ end trace 29cd0273421f55a6 ]--- ---------------- END OF BUG REPORT --------------------------- I can assure you though that this problem is not restricted only to direct I/O. The following (incomplete due to a broken pipe) bug report is when writing without direct I/O flag: ---------------- START OF BUG REPORT --------------------------- May 14 10:45:18 dimension7 kernel: [ 5408.870981] ------------[ cut here ]------------ May 14 10:45:18 dimension7 kernel: [ 5408.871019] kernel BUG at drivers/scsi/scsi_lib.c:1153! May 14 10:45:18 dimension7 kernel: [ 5408.871051] invalid opcode: 0000 [#1] SMP Message from syslogd@dimension7 at May 14 10:45:18 ... kernel:[ 5408.870981] ------------[ cut here ]------------ Message from syslogd@dimension7 at May 14 10:45:18 ... kernel:[ 5408.871051] invalid opcode: 0000 [#1] SMP May 14 10:45:18 dimension7 kernel: [ 5408.871082] Modules linked in: ext4 jbd2 xt_tcpudp nf_conntrack_ipv4 nf_defrag_ipv4 xt_state nf_conntrack iwlwifi acpi_cpufreq mperf cpufreq_stats cpufreq_powersave cpufreq_conservative cpufreq_userspace ebtable_nat ebtables ip6table_filter ip6_tables iptable_filter ip_tables x_tables parport_pc ppdev lp parport bnep rfcomm cryptd binfmt_misc aes_i586 aes_generic uinput fuse nfsd nfs nfs_acl auth_rpcgss fscache lockd sunrpc loop snd_hda_codec_hdmi snd_hda_codec_realtek arc4 snd_hda_intel snd_hda_codec snd_hwdep snd_pcm snd_page_alloc snd_seq snd_seq_device snd_timer mac80211 snd joydev cfg80211 i915 btusb uvcvideo bluetooth videodev soundcore drm_kms_helper drm media psmouse i2c_algo_bit battery evdev i2c_i801 rfkill i2c_core iTCO_wdt iTCO_vendor_support serio_raw ac power_supply crc16 pcspkr video button processor ext3 mbcache jbd btrfs crc32c libcrc32c zlib_deflate dm_mod sr_mod cdrom sd_mod crc_t10dif thermal fan thermal_sys ahci libahci ehci_hcd libata r8169 mii scsi_mod usb May 14 10:45:18 dimension7 kernel: core usb_common [last unloaded: iwlwifi] May 14 10:45:18 dimension7 kernel: [ 5408.871790] May 14 10:45:18 dimension7 kernel: [ 5408.871802] Pid: 4265, comm: flush-254:0 Not tainted 3.2.14-apyrgio-bcache-12.2+ #1 SAMSUNG ELECTRONICS CO., LTD. 300E4A/300E5A/300E7A/3430EA/3530EA/300E4A/300E5A/300E7A/3430EA/3530EA May 14 10:45:18 dimension7 kernel: [ 5408.871903] EIP: 0060:[<f8249c1e>] EFLAGS: 00010046 CPU: 0 May 14 10:45:18 dimension7 kernel: [ 5408.871943] EIP is at scsi_setup_fs_cmnd+0x3b/0x72 [scsi_mod] May 14 10:45:18 dimension7 kernel: [ 5408.871978] EAX: 00000000 EBX: f1ecec00 ECX: f1ecec00 EDX: eb5ebb40 May 14 10:45:18 dimension7 kernel: [ 5408.872016] ESI: eb5ebb40 EDI: f6c1f400 EBP: 00000000 ESP: d0291ae8 May 14 10:45:18 dimension7 kernel: [ 5408.872052] DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068 May 14 10:45:18 dimension7 kernel: [ 5408.872086] Process flush-254:0 (pid: 4265, ti=d0290000 task=f0c709a0 task.ti=d0290000) May 14 10:45:18 dimension7 kernel: [ 5408.872131] Stack: May 14 10:45:18 dimension7 kernel: [ 5408.872144] 00044010 00000000 f6c1f400 f83375d1 c1158870 eb5ebb40 00000000 f1e75800 May 14 10:45:18 dimension7 kernel: [ 5408.872205] eb5ebb40 00000001 f1ecec00 c115a8ff 06a96028 f1ed9ad8 f1e75a01 00000000 May 14 10:45:18 dimension7 kernel: [ 5408.872264] eb5ebb40 f1ed9ad8 f1ed9ad8 f1ecec28 c114e00b f1ecec00 f1f22400 f1ed9ad8 May 14 10:45:18 dimension7 kernel: [ 5408.872324] Call Trace: May 14 10:45:18 dimension7 kernel: [ 5408.872346] [<f83375d1>] ? sd_prep_fn+0x2a5/0xb3e [sd_mod] May 14 10:45:18 dimension7 kernel: [ 5408.872383] [<c1158870>] ? cfq_dispatch_insert+0xc0/0xc7 May 14 10:45:18 dimension7 kernel: [ 5408.872416] [<c115a8ff>] ? cfq_dispatch_requests+0x635/0x751 May 14 10:45:18 dimension7 kernel: [ 5408.872452] [<c114e00b>] ? blk_peek_request+0xad/0x17a May 14 10:45:18 dimension7 kernel: [ 5408.872490] [<f82496c6>] ? scsi_request_fn+0x4d/0x38c [scsi_mod] May 14 10:45:18 dimension7 kernel: [ 5408.872527] [<c1149e2f>] ? __blk_run_queue+0x11/0x12 May 14 10:45:18 dimension7 kernel: [ 5408.872558] [<c114dc3e>] ? queue_unplugged+0x5e/0x6c May 14 10:45:18 dimension7 kernel: [ 5408.872590] [<c114e338>] ? blk_flush_plug_list+0x153/0x162 May 14 10:45:18 dimension7 kernel: [ 5408.872625] [<c12d6312>] ? io_schedule_timeout+0x3a/0x6a May 14 10:45:18 dimension7 kernel: [ 5408.872660] [<c10979bf>] ? mempool_alloc+0xbb/0xd7 May 14 10:45:18 dimension7 kernel: [ 5408.872691] [<c104d628>] ? add_wait_queue+0x30/0x30 May 14 10:45:18 dimension7 kernel: [ 5408.872723] [<c10eca6a>] ? bio_alloc_bioset+0x23/0x9e May 14 10:45:18 dimension7 kernel: [ 5408.872754] [<c10ecb49>] ? bio_alloc+0xb/0x20 May 14 10:45:18 dimension7 kernel: [ 5408.872789] [<f9531677>] ? ext4_bio_write_page+0x1ec/0x335 [ext4] May 14 10:45:18 dimension7 kernel: [ 5408.872831] [<f952e492>] ? mpage_da_submit_io+0x30c/0x3ab [ext4] May 14 10:45:18 dimension7 kernel: [ 5408.872873] [<f95301ea>] ? mpage_da_map_and_submit+0x39f/0x3ae [ext4] May 14 10:45:18 d ---------------- END OF BUG REPORT --------------------------- All the above can be reproduced at will. Well, does anyone have a clue? If more debug info is needed, I'll be glad to provide it. Regards, Alex *this test is moot of course. I did as the simplest work scenario to check if everything works ok. -- Alex Pyrgiotis, a.k.a 03107422 Undergrad Student School of Electrical & Computer Engineering National Technical University of Athens, Greece Paper Street Soap Co. work: (288) 555-0153 -- To unsubscribe from this list: send the line "unsubscribe linux-bcache" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
