Hi, I have a few bcache questions: How does clear_stats work? For example if I do the following: dd if=/dev/zero of=/dev/bcache0 bs=512 count=1 oflag=direct grep -r . /sys/block/bcache0/bcache/stats_five_minute/ echo 1 > /sys/block/bcache0/bcache/clear_stats grep -r . /sys/block/bcache0/bcache/stats_five_minute/ the results of the grep are the same on 3.13.5-200.fc20.x86_64 . Is this to be expected? Is it possible to quickly invalidate the cache so that it is known that it is empty? Will doing echo d8c40aa6-27b8-420e-abe2-1e2e7b31e74a > /sys/block/bcache0/bcache/detach echo d8c40aa6-27b8-420e-abe2-1e2e7b31e74a > /sys/block/bcache0/bcache/attach throw away the contents of the caching device? Is it possible to invalidate the cache without destroying /dev/bcache0 ? How do I flush the cache to backing device as quickly as possible regardless of the usual throttling? Should attaching the same cache set multiple times be producing WARNINGs? [ 2043.396173] ------------[ cut here ]------------ [ 2043.396223] WARNING: CPU: 1 PID: 814 at fs/sysfs/dir.c:486 sysfs_warn_dup+0x86/0xa0() [ 2043.396291] sysfs: cannot create duplicate filename '/devices/LNXSYSTM:00/device:00/PNP0A03:00/device:08/VMBUS:00/vmbus_0_5/host3/target3:0:0/3:0:0:4/block/sdf/bcache/cache' [ 2043.396399] Modules linked in: iscsi_target_mod target_core_mod iscsi_tcp libiscsi_tcp libiscsi scsi_transport_iscsi crct10dif_pclmul crc32_pclmul ghash_clmulni_intel microcode serio_raw hyperv_keyboard snd_pcsp hv_netvsc i2c_piix4 i2c_core snd_pcm snd_page_alloc snd_timer snd soundcore hv_utils hyperv_fb bcache hid_hyperv hv_storvsc crc32c_intel ata_generic pata_acpi hv_vmbus dm_multipath [ 2043.396791] CPU: 1 PID: 814 Comm: bash Not tainted 3.13.5-200.fc20.x86_64 #1 [ 2043.396880] Hardware name: Microsoft Corporation Virtual Machine/Virtual Machine, BIOS 090006 05/23/2012 [ 2043.397006] 0000000000000009 ffff8800f3233c58 ffffffff81686fdc ffff8800f3233ca0 [ 2043.397113] ffff8800f3233c90 ffffffff8106d47d ffff8800e403f000 ffff8800e403f000 [ 2043.397218] ffff88007ec5f620 0000000000000001 0000000000000000 ffff8800f3233cf0 [ 2043.397319] Call Trace: [ 2043.397365] [<ffffffff81686fdc>] dump_stack+0x45/0x56 [ 2043.397440] [<ffffffff8106d47d>] warn_slowpath_common+0x7d/0xa0 [ 2043.397525] [<ffffffff8106d4ec>] warn_slowpath_fmt+0x4c/0x50 [ 2043.397634] [<ffffffff812307a6>] sysfs_warn_dup+0x86/0xa0 [ 2043.397710] [<ffffffff81230800>] sysfs_add_one+0x40/0x50 [ 2043.397786] [<ffffffff81231371>] sysfs_do_create_link_sd.isra.2+0xc1/0x1f0 [ 2043.397883] [<ffffffff812314c5>] sysfs_create_link+0x25/0x50 [ 2043.397976] [<ffffffffa005cf2e>] bcache_device_link+0x9e/0xf0 [bcache] [ 2043.398080] [<ffffffffa005e832>] bch_cached_dev_attach+0x212/0x450 [bcache] [ 2043.398184] [<ffffffffa00643cb>] bch_cached_dev_store+0x6db/0x770 [bcache] [ 2043.398252] [<ffffffff8122f260>] ? sysfs_write_file+0x60/0x1c0 [ 2043.398299] [<ffffffff8122f328>] sysfs_write_file+0x128/0x1c0 [ 2043.398344] [<ffffffff811b8ab4>] vfs_write+0xb4/0x1f0 [ 2043.398383] [<ffffffff811b94e9>] SyS_write+0x49/0xa0 [ 2043.398423] [<ffffffff81695fa9>] system_call_fastpath+0x16/0x1b [ 2043.398466] ---[ end trace e55ca2066db90472 ]--- [ 2043.398502] ------------[ cut here ]------------ [ 2043.398545] WARNING: CPU: 1 PID: 814 at drivers/md/bcache/super.c:689 bcache_device_link+0xbc/0xf0 [bcache]() [ 2043.398651] Couldn't create device <-> cache set symlinks [ 2043.398717] Modules linked in: [ 2043.400814] iscsi_target_mod target_core_mod iscsi_tcp libiscsi_tcp libiscsi scsi_transport_iscsi crct10dif_pclmul crc32_pclmul ghash_clmulni_intel microcode serio_raw hyperv_keyboard snd_pcsp hv_netvsc i2c_piix4 i2c_core snd_pcm snd_page_alloc snd_timer snd soundcore hv_utils hyperv_fb bcache hid_hyperv hv_storvsc crc32c_intel ata_generic pata_acpi hv_vmbus dm_multipath [ 2043.407935] CPU: 1 PID: 814 Comm: bash Tainted: G W 3.13.5-200.fc20.x86_64 #1 [ 2043.409841] Hardware name: Microsoft Corporation Virtual Machine/Virtual Machine, BIOS 090006 05/23/2012 [ 2043.413376] 0000000000000009 ffff8800f3233d00 ffffffff81686fdc ffff8800f3233d48 [ 2043.415145] ffff8800f3233d38 ffffffff8106d47d ffff8800f073008c ffff8800f0730040 [ 2043.416965] ffff88007eec0040 ffffffffa006ac98 ffff88007eec0cd0 ffff8800f3233d98 [ 2043.418686] Call Trace: [ 2043.420428] [<ffffffff81686fdc>] dump_stack+0x45/0x56 [ 2043.422112] [<ffffffff8106d47d>] warn_slowpath_common+0x7d/0xa0 [ 2043.423784] [<ffffffff8106d4ec>] warn_slowpath_fmt+0x4c/0x50 [ 2043.425478] [<ffffffffa005cf4c>] bcache_device_link+0xbc/0xf0 [bcache] [ 2043.427298] [<ffffffffa005e832>] bch_cached_dev_attach+0x212/0x450 [bcache] [ 2043.428963] [<ffffffffa00643cb>] bch_cached_dev_store+0x6db/0x770 [bcache] [ 2043.430563] [<ffffffff8122f260>] ? sysfs_write_file+0x60/0x1c0 [ 2043.432145] [<ffffffff8122f328>] sysfs_write_file+0x128/0x1c0 [ 2043.433743] [<ffffffff811b8ab4>] vfs_write+0xb4/0x1f0 [ 2043.435335] [<ffffffff811b94e9>] SyS_write+0x49/0xa0 [ 2043.436877] [<ffffffff81695fa9>] system_call_fastpath+0x16/0x1b [ 2043.438434] ---[ end trace e55ca2066db90473 ]--- [ 2043.439973] bcache: bch_cached_dev_attach() Caching sdf as bcache0 on set d8c40aa6-27b8-420e-abe2-1e2e7b31e74a [ 2112.863194] bcache: bch_cached_dev_attach() Can't attach sdf: already attached [ 2112.863256] bcache: __cached_dev_store() Can't attach d8c40aa6-27b8-420e-abe2-1e2e7b31e74a Finally, is it possible to limit the amount of cache a particular backing device can use? -- Sitsofe | http://sucs.org/~sits/ -- 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
