Hi! Short summary: I suspect that rsync´ing files to a newly created BTRFS partition with a subvolume *and* enabled space_cache triggers the error mentioned in the subject line of this mail. I reported this also as:
Bug 38112 - btrfs: failed to load free space cache for block group on rsync´ing to space_cache BTRFS with subvolume https://bugzilla.kernel.org/show_bug.cgi?id=38112 I will add a reference to my post here to the bug report, so feel free to use whatever suits you best to follow up. This happened on a ThinkPad T520 with 3.0.0-rc3-amd64 Debian/GNU Linux kernel. The issue happened on a 2.5 inch external eSATA/USB harddisk which I changed to BTRFS. On the repoot after the rsync process was stalled the unrelated non space cache using root filesystem did not mount anymore with 3.0.0-rc3-amd64 and 2.6.39-2-amd64 kernel. But thankfully it did mount with a 2.6.38 grml 2011 amd64 kernel and now work again. Thus I did merkaba:~> mkfs.btrfs -L daten /dev/sdc2 WARNING! - Btrfs Btrfs v0.19 IS EXPERIMENTAL WARNING! - see http://btrfs.wiki.kernel.org before using fs created label daten on /dev/sdc2 nodesize 4096 leafsize 4096 sectorsize 4096 size 447.13GB Btrfs Btrfs v0.19 merkaba:~> mount -o space_cache,compress=lzo /dev/sdc2 /mnt/amazon-daten merkaba:~> dmesg | tail -3 [137440.930038] device label daten devid 1 transid 7 /dev/sdc2 [137440.930507] btrfs: enabling disk space caching [137440.930518] btrfs: use lzo compression Then I unmounted, added a fstab entry without space_cache option since I read that once BTRFS created a space_cache it would use it anyway it is mounted with clear_cache to clear the cache again. I created a sub volume for movies, cause I wanted to be able to not snapshot the movie files: merkaba:~> btrfs subvolume create /mnt/amazon-daten/Filme Create subvolume '/mnt/amazon-daten/Filme' I then did my rsync from the backup which BTW was a BTRFS with space_cache as well - created today: merkaba:~> rsync -a -H --acls --xattrs --sparse /mnt/steigerwald-daten/ /mnt/amazon-daten A short while after starting the rsync I got: 137927.147255] btrfs: failed to load free space cache for block group 147131990016 [138110.390962] ------------[ cut here ]------------ [138110.392736] kernel BUG at /media/data/mattems/src/linux-2.6-3.0.0~rc3/debian/build/source_amd64_none/fs/btrfs/free- space-cache.c:1186! [138110.394536] invalid opcode: 0000 [#1] SMP [138110.396322] CPU 0 [138110.396331] Modules linked in: ufs qnx4 hfsplus hfs minix ntfs vfat msdos fat jfs xfs reiserfs ext3 jbd ext2 ums_cypress usb_storage uas tun cpufreq_conservative cpufreq_stats parport_pc ppdev cpufreq_powersave cpufreq_userspace lp parport bnep acpi_cpufreq mperf rfcomm bluetooth uinput fuse nfsd nfs lockd fscache auth_rpcgss nfs_acl sunrpc ext4 mbcache jbd2 crc16 acpiphp pci_hotplug loop firewire_sbp2 snd_hda_codec_hdmi snd_hda_codec_conexant joydev arc4 snd_hda_intel snd_hda_codec snd_hwdep ac snd_pcm snd_seq snd_timer snd_seq_device thinkpad_acpi tpm_tis snd nvram psmouse tpm battery evdev serio_raw i2c_i801 pcspkr tpm_bios power_supply i915 wmi drm_kms_helper soundcore snd_page_alloc rfkill drm i2c_algo_bit i2c_core video button processor dm_mod raid10 raid456 async_raid6_recov async_pq raid6_pq async_xor xor async_memcpy async_tx raid1 raid0 multipath linear md_mod btrfs zlib_deflate crc32c libcrc32c sg sr_mod sd_mod cdrom crc_t10dif usbhid sdhci_pci firewire_ohci sdhci hid mmc_core ahci sata_sil24 libahci libata firewire_core crc_itu_t scsi_mod ehci_hcd thermal thermal_sys usbcore e1000e [last unloaded: cfg80211] [138110.407957] [138110.409950] Pid: 26438, comm: btrfs-transacti Tainted: G W 3.0.0-rc3-amd64 #1 LENOVO 42433WG/42433WG [138110.411984] RIP: 0010:[<ffffffffa01b845b>] [<ffffffffa01b845b>] recalculate_thresholds+0x21/0x6c [btrfs] [138110.414051] RSP: 0018:ffff880182b2fcd8 EFLAGS: 00010202 [138110.416107] RAX: 0000000000000001 RBX: ffff880212442440 RCX: 0000000008000000 [138110.418179] RDX: 0000000007ffffff RSI: 0000000000000002 RDI: ffff880212442440 [138110.420244] RBP: 0000000000000000 R08: 0000000008000000 R09: ffff88019a155720 [138110.422297] R10: ffff880105f6e3b8 R11: ffff880100000001 R12: ffff88020f220ba0 [138110.424356] R13: 0000002241fdd000 R14: ffff880105f6e3b8 R15: 0000000000001000 [138110.426410] FS: 0000000000000000(0000) GS:ffff88021e200000(0000) knlGS:0000000000000000 [138110.428467] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b [138110.430522] CR2: 00007f0529281034 CR3: 0000000146086000 CR4: 00000000000406f0 [138110.432576] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [138110.434620] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 [138110.436656] Process btrfs-transacti (pid: 26438, threadinfo ffff880182b2e000, task ffff880212054140) [138110.438704] Stack: [138110.440740] ffffffffa01baa5e ffff880105f6e390 ffff8802092f7c80 0000000005f6c0b8 [138110.442788] ffff8802092f7d58 0000000000000001 ffff8802092f7c80 0000000000001000 [138110.444814] 0000002241fdd000 0000002241fddfff 0000002241fde000 ffff880105f6c000 [138110.446836] Call Trace: [138110.448914] [<ffffffffa01baa5e>] ? __btrfs_add_free_space+0x1fc/0x2f4 [btrfs] [138110.450923] [<ffffffffa01781e7>] ? unpin_extent_range+0x95/0x131 [btrfs] [138110.452917] [<ffffffffa0179c57>] ? btrfs_finish_extent_commit+0xab/0x19f [btrfs] [138110.454902] [<ffffffffa018afb6>] ? btrfs_commit_transaction+0x566/0x67e [btrfs] [138110.456874] [<ffffffff8105ff19>] ? wake_up_bit+0x20/0x20 [138110.458838] [<ffffffffa018b507>] ? start_transaction+0x1f5/0x242 [btrfs] [138110.460786] [<ffffffffa0185fd3>] ? transaction_kthread+0x173/0x22d [btrfs] [138110.462733] [<ffffffffa0185e60>] ? find_and_setup_root+0xcb/0xcb [btrfs] [138110.464658] [<ffffffffa0185e60>] ? find_and_setup_root+0xcb/0xcb [btrfs] [138110.466541] [<ffffffff8105fadd>] ? kthread+0x7a/0x82 [138110.468411] [<ffffffff8133dd24>] ? kernel_thread_helper+0x4/0x10 [138110.470274] [<ffffffff8105fa63>] ? kthread_worker_fn+0x147/0x147 [138110.472111] [<ffffffff8133dd20>] ? gs_change+0x13/0x13 [138110.473928] Code: 30 48 c7 47 20 00 00 00 00 c3 48 8b 47 38 31 d2 8b 77 20 4c 8b 40 70 48 8b 48 09 49 c1 e0 0f 49 8d 44 08 ff 49 f7 f0 39 c6 7e 04 <0f> 0b eb fe 48 81 f9 ff ff ff 3f b8 00 80 00 00 76 0b 48 89 c8 [138110.475922] RIP [<ffffffffa01b845b>] recalculate_thresholds+0x21/0x6c [btrfs] [138110.477847] RSP <ffff880182b2fcd8> [138110.549460] ---[ end trace 131766a12388cd20 ]--- [138138.490877] BUG: soft lockup - CPU#2 stuck for 22s! [btrfs-delayed- m:26480] [138138.490885] Modules linked in: ufs qnx4 hfsplus hfs minix ntfs vfat msdos fat jfs xfs reiserfs ext3 jbd ext2 ums_cypress usb_storage uas tun cpufreq_conservative cpufreq_stats parport_pc ppdev cpufreq_powersave cpufreq_userspace lp parport bnep acpi_cpufreq mperf rfcomm bluetooth uinput fuse nfsd nfs lockd fscache auth_rpcgss nfs_acl sunrpc ext4 mbcache jbd2 crc16 acpiphp pci_hotplug loop firewire_sbp2 snd_hda_codec_hdmi snd_hda_codec_conexant joydev arc4 snd_hda_intel snd_hda_codec snd_hwdep ac snd_pcm snd_seq snd_timer snd_seq_device thinkpad_acpi tpm_tis snd nvram psmouse tpm battery evdev serio_raw i2c_i801 pcspkr tpm_bios power_supply i915 wmi drm_kms_helper soundcore snd_page_alloc rfkill drm i2c_algo_bit i2c_core video button processor dm_mod raid10 raid456 async_raid6_recov async_pq raid6_pq async_xor xor async_memcpy async_tx raid1 raid0 multipath linear md_mod btrfs zlib_deflate crc32c libcrc32c sg sr_mod sd_mod cdrom crc_t10dif usbhid sdhci_pci firewire_ohci sdhci hid mmc_core ahci sata_sil24 libahci libata firewire_core crc_itu_t scsi_mod ehci_hcd thermal thermal_sys usbcore e1000e [last unloaded: cfg80211] [138138.491076] CPU 2 [138138.491079] Modules linked in: ufs qnx4 hfsplus hfs minix ntfs vfat msdos fat jfs xfs reiserfs ext3 jbd ext2 ums_cypress usb_storage uas tun cpufreq_conservative cpufreq_stats parport_pc ppdev cpufreq_powersave cpufreq_userspace lp parport bnep acpi_cpufreq mperf rfcomm bluetooth uinput fuse nfsd nfs lockd fscache auth_rpcgss nfs_acl sunrpc ext4 mbcache jbd2 crc16 acpiphp pci_hotplug loop firewire_sbp2 snd_hda_codec_hdmi snd_hda_codec_conexant joydev arc4 snd_hda_intel snd_hda_codec snd_hwdep ac snd_pcm snd_seq snd_timer snd_seq_device thinkpad_acpi tpm_tis snd nvram psmouse tpm battery evdev serio_raw i2c_i801 pcspkr tpm_bios power_supply i915 wmi drm_kms_helper soundcore snd_page_alloc rfkill drm i2c_algo_bit i2c_core video button processor dm_mod raid10 raid456 async_raid6_recov async_pq raid6_pq async_xor xor async_memcpy async_tx raid1 raid0 multipath linear md_mod btrfs zlib_deflate crc32c libcrc32c sg sr_mod sd_mod cdrom crc_t10dif usbhid sdhci_pci firewire_ohci sdhci hid mmc_core ahci sata_sil24 libahci libata firewire_core crc_itu_t scsi_mod ehci_hcd thermal thermal_sys usbcore e1000e [last unloaded: cfg80211] [138138.491241] [138138.491248] Pid: 26480, comm: btrfs-delayed-m Tainted: G D W 3.0.0-rc3-amd64 #1 LENOVO 42433WG/42433WG [138138.491258] RIP: 0010:[<ffffffff81337607>] [<ffffffff81337607>] _raw_spin_lock+0x13/0x1b [138138.491276] RSP: 0018:ffff8801011ff958 EFLAGS: 00000297 [138138.491282] RAX: 000000000000143d RBX: ffff88019576cc28 RCX: 0000000000001000 [138138.491288] RDX: 000000000000143c RSI: ffff8802092f7c80 RDI: ffff880212442440 [138138.491294] RBP: ffff880105f6e390 R08: 0000002241c8c000 R09: ffffffffffffffff [138138.491299] R10: dead000000200200 R11: 0000000000000000 R12: ffffffff8133d5ce [138138.491305] R13: 0000000000000000 R14: 0000000000000af7 R15: ffffffffa01a4f88 [138138.491312] FS: 0000000000000000(0000) GS:ffff88021e280000(0000) knlGS:0000000000000000 [138138.491318] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b [138138.491324] CR2: 00007f9be3bed000 CR3: 0000000001603000 CR4: 00000000000406e0 [138138.491329] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [138138.491335] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 [138138.491342] Process btrfs-delayed-m (pid: 26480, threadinfo ffff8801011fe000, task ffff8801c2b3d120) [138138.491347] Stack: [138138.491351] ffffffffa017fbcc ffff880189996b40 ffff880100000021 0000000000000000 [138138.491361] 0000000000001000 0000000003856f00 ffffffffa01a4300 ffff880105f6e394 [138138.491371] 0000000000000000 0000002241c8c000 00010000a01a4300 ffff880138b41800 [138138.491382] Call Trace: [138138.491419] [<ffffffffa017fbcc>] ? find_free_extent+0x542/0xa4b [btrfs] [138138.491456] [<ffffffffa01a4300>] ? map_private_extent_buffer+0xa3/0xc4 [btrfs] [138138.491489] [<ffffffffa0180191>] ? btrfs_reserve_extent+0xbc/0x1cd [btrfs] [138138.491518] [<ffffffffa0178ffd>] ? reserve_metadata_bytes+0x54/0x1a6 [btrfs] [138138.491548] [<ffffffffa0180403>] ? btrfs_alloc_free_block+0x161/0x292 [btrfs] [138138.491575] [<ffffffffa0173091>] ? __btrfs_cow_block+0x109/0x34b [btrfs] [138138.491586] [<ffffffff810415ab>] ? check_preempt_wakeup+0x11f/0x19f [138138.491612] [<ffffffffa0173862>] ? btrfs_cow_block+0xf7/0x143 [btrfs] [138138.491639] [<ffffffffa0175135>] ? btrfs_search_slot+0x140/0x4c6 [btrfs] [138138.491647] [<ffffffff81008596>] ? __switch_to+0xc5/0x288 [138138.491654] [<ffffffff8103b918>] ? pick_next_task_fair+0xf9/0x10b [138138.491664] [<ffffffff81336c31>] ? mutex_lock+0xd/0x2c [138138.491695] [<ffffffffa01839ad>] ? btrfs_lookup_inode+0x25/0x84 [btrfs] [138138.491704] [<ffffffff81336c31>] ? mutex_lock+0xd/0x2c [138138.491733] [<ffffffffa01c59ae>] ? btrfs_update_delayed_inode+0x6b/0x126 [btrfs] [138138.491767] [<ffffffffa018b507>] ? start_transaction+0x1f5/0x242 [btrfs] [138138.491795] [<ffffffffa01c640f>] ? btrfs_async_run_delayed_node_done+0x8a/0x138 [btrfs] [138138.491828] [<ffffffffa01ae872>] ? worker_loop+0x186/0x4a1 [btrfs] [138138.491837] [<ffffffff813361ea>] ? schedule+0x5ed/0x61a [138138.491866] [<ffffffffa01ae6ec>] ? btrfs_queue_worker+0x24a/0x24a [btrfs] [138138.491894] [<ffffffffa01ae6ec>] ? btrfs_queue_worker+0x24a/0x24a [btrfs] [138138.491904] [<ffffffff8105fadd>] ? kthread+0x7a/0x82 [138138.491914] [<ffffffff8133dd24>] ? kernel_thread_helper+0x4/0x10 [138138.491923] [<ffffffff8105fa63>] ? kthread_worker_fn+0x147/0x147 [138138.491932] [<ffffffff8133dd20>] ? gs_change+0x13/0x13 [138138.491936] Code: 00 01 00 75 04 f0 0f b1 17 0f 94 c2 0f b6 c2 85 c0 0f 95 c0 0f b6 c0 c3 b8 00 00 01 00 f0 0f c1 07 0f b7 d0 c1 e8 10 39 c2 74 07 <f3> 90 0f b7 17 eb f5 c3 9c 58 66 66 90 66 90 48 89 c2 fa 66 66 [138138.492000] Call Trace: [138138.492029] [<ffffffffa017fbcc>] ? find_free_extent+0x542/0xa4b [btrfs] [138138.492062] [<ffffffffa01a4300>] ? map_private_extent_buffer+0xa3/0xc4 [btrfs] [138138.492092] [<ffffffffa0180191>] ? btrfs_reserve_extent+0xbc/0x1cd [btrfs] [138138.492121] [<ffffffffa0178ffd>] ? reserve_metadata_bytes+0x54/0x1a6 [btrfs] [138138.492150] [<ffffffffa0180403>] ? btrfs_alloc_free_block+0x161/0x292 [btrfs] [138138.492176] [<ffffffffa0173091>] ? __btrfs_cow_block+0x109/0x34b [btrfs] [138138.492185] [<ffffffff810415ab>] ? check_preempt_wakeup+0x11f/0x19f [138138.492211] [<ffffffffa0173862>] ? btrfs_cow_block+0xf7/0x143 [btrfs] [138138.492238] [<ffffffffa0175135>] ? btrfs_search_slot+0x140/0x4c6 [btrfs] [138138.492245] [<ffffffff81008596>] ? __switch_to+0xc5/0x288 [138138.492251] [<ffffffff8103b918>] ? pick_next_task_fair+0xf9/0x10b [138138.492260] [<ffffffff81336c31>] ? mutex_lock+0xd/0x2c [138138.492289] [<ffffffffa01839ad>] ? btrfs_lookup_inode+0x25/0x84 [btrfs] [138138.492298] [<ffffffff81336c31>] ? mutex_lock+0xd/0x2c [138138.492326] [<ffffffffa01c59ae>] ? btrfs_update_delayed_inode+0x6b/0x126 [btrfs] [138138.492359] [<ffffffffa018b507>] ? start_transaction+0x1f5/0x242 [btrfs] [138138.492387] [<ffffffffa01c640f>] ? btrfs_async_run_delayed_node_done+0x8a/0x138 [btrfs] [138138.492417] [<ffffffffa01ae872>] ? worker_loop+0x186/0x4a1 [btrfs] [138138.492426] [<ffffffff813361ea>] ? schedule+0x5ed/0x61a [138138.492453] [<ffffffffa01ae6ec>] ? btrfs_queue_worker+0x24a/0x24a [btrfs] [138138.492480] [<ffffffffa01ae6ec>] ? btrfs_queue_worker+0x24a/0x24a [btrfs] [138138.492489] [<ffffffff8105fadd>] ? kthread+0x7a/0x82 [138138.492498] [<ffffffff8133dd24>] ? kernel_thread_helper+0x4/0x10 [138138.492507] [<ffffffff8105fa63>] ? kthread_worker_fn+0x147/0x147 [138138.492516] [<ffffffff8133dd20>] ? gs_change+0x13/0x13 merkaba:~> Message from syslogd@merkaba at Jun 23 18:30:41 ... kernel:[138166.427817] Stack: Message from syslogd@merkaba at Jun 23 18:30:41 ... kernel:[138166.427851] Call Trace: Message from syslogd@merkaba at Jun 23 18:30:41 ... kernel:[138166.428406] Code: 00 01 00 75 04 f0 0f b1 17 0f 94 c2 0f b6 c2 85 c0 0f 95 c0 0f b6 c0 c3 b8 00 00 01 00 f0 0f c1 07 0f b7 d0 c1 e8 10 39 c2 74 07 <f3> 90 0f b7 17 eb f5 c3 9c 58 66 66 90 66 90 48 89 c2 fa 66 66 Message from syslogd@merkaba at Jun 23 18:30:46 ... kernel:[138171.396102] Stack: Message from syslogd@merkaba at Jun 23 18:30:46 ... kernel:[138171.396150] Call Trace: Message from syslogd@merkaba at Jun 23 18:30:46 ... kernel:[138171.396227] Code: e0 ff ff a8 08 75 0e e8 7e ba da e0 66 90 fa 66 66 90 66 66 90 65 48 8b 04 25 08 cd 00 00 83 88 3c e0 ff ff 04 eb 0c 8b 57 04 ec Message from syslogd@merkaba at Jun 23 18:30:46 ... kernel:[138171.396667] Stack: Message from syslogd@merkaba at Jun 23 18:30:46 ... kernel:[138171.396700] Call Trace: Message from syslogd@merkaba at Jun 23 18:30:46 ... kernel:[138171.396703] <IRQ> Message from syslogd@merkaba at Jun 23 18:30:46 ... kernel:[138171.396840] <EOI> Message from syslogd@merkaba at Jun 23 18:30:46 ... kernel:[138171.397396] Code: 41 ff c0 4c 89 0c 07 48 83 c0 08 41 39 c8 7c e8 c3 48 63 c9 45 31 c0 45 31 c9 48 83 c1 3f 45 31 d2 48 c1 e9 06 eb 19 4a 8b 04 02 Message from syslogd@merkaba at Jun 23 18:30:46 ... kernel:[138171.398412] Stack: Message from syslogd@merkaba at Jun 23 18:30:46 ... kernel:[138171.398447] Call Trace: Message from syslogd@merkaba at Jun 23 18:30:46 ... kernel:[138171.398451] <IRQ> Message from syslogd@merkaba at Jun 23 18:30:46 ... kernel:[138171.398485] <EOI> Message from syslogd@merkaba at Jun 23 18:30:46 ... kernel:[138171.398574] Code: 44 e0 ff ff 00 00 01 00 48 63 80 44 e0 ff ff a9 00 ff ff 07 75 37 65 8b 04 25 80 26 01 00 85 c0 74 2b 80 3d 2d a2 63 00 00 75 07 <e8> 4e f4 fb ff eb 1b 65 48 8b 3c 25 70 e6 00 00 48 85 ff 74 0d Since the backup process was stalled, rsync was D+ and umount -lf did hang, too. I decided that it would be better to reboot my machine. Then I was scared away that neither 3.0.0-rc3-amd64 and 2.6.39-2-amd64 debian kernel were able to mount a completely unrelated BTRFS filesystem. Namely my BTRFS root filesystem located on an Intel SSD 320 with 300 GB. I got a backtrace I unfortunately did not photograph, cause I thought I will see it on recovery with GRML anyway, and got dumped to initramfs shell. On an other ThinkPad, a T42, I grabbed grml 2011.05 64-Bit and dd´d it a an USB stick. And thanks God there, with a 2.6.38 grml kernel, my BTRFS root filesystem did mount well. Just for sure I run a mount -o clear_cache on the root filesystem although I never activated space_cache there. Then I rebooted into my Debian Unstable and all was well again. The only hints in syslog I found were: 1741 Jun 23 18:15:34 merkaba kernel: [137261.752879] ata6: SATA link up 3.0 Gbps (SStatus 123 SControl 300) 1742 Jun 23 18:15:34 merkaba kernel: [137261.753946] ata6.00: ACPI cmd ef/02:00:00:00:00:a0 (SET FEATURES) succeeded 1743 Jun 23 18:15:34 merkaba kernel: [137261.753956] ata6.00: ACPI cmd f5/00:00:00:00:00:a0 (SECURITY FREEZE LOCK) filtered out 1744 Jun 23 18:15:34 merkaba kernel: [137261.756041] ata6.00: ACPI cmd ef/02:00:00:00:00:a0 (SET FEATURES) succeeded 1745 Jun 23 18:15:34 merkaba kernel: [137261.756055] ata6.00: ACPI cmd f5/00:00:00:00:00:a0 (SECURITY FREEZE LOCK) filtered out 1746 Jun 23 18:15:34 merkaba kernel: [137261.757703] ata6.00: configured for UDMA/133 1747 Jun 23 18:15:34 merkaba kernel: [137261.772834] ata6: EH complete 1748 Jun 23 18:17:01 merkaba /USR/SBIN/CRON[25888]: (root) CMD ( cd / && run-parts --report /etc/cron.hourly) 1749 Jun 23 18:18:34 merkaba kernel: [137440.930038] device label daten devid 1 transid 7 /dev/sdc2 1750 Jun 23 18:18:34 merkaba kernel: [137440.930507] btrfs: enabling disk space caching 1751 Jun 23 18:18:34 merkaba kernel: [137440.930518] btrfs: use lzo compression 1752 Jun 23 18:22:00 merkaba kernel: [137646.534245] device label daten devid 1 transid 10 /dev/sdc2 1753 Jun 23 18:22:00 merkaba kernel: [137646.534556] btrfs: use lzo compression 1754 Jun 23 18:22:00 merkaba kernel: [137646.549740] btrfs: disk space caching is enabled 1755 Jun 23 18:24:48 merkaba kernel: [137813.653916] device label daten- backup devid 1 transid 162 /dev/mapper/steigerwald-daten 1756 Jun 23 18:24:48 merkaba kernel: [137813.654566] btrfs: use lzo compression 1757 Jun 23 18:24:48 merkaba kernel: [137813.691677] btrfs: disk space caching is enabled 1758 Jun 23 18:26:41 merkaba kernel: [137927.147252] block group 147131990016 has an wrong amount of free space 1759 Jun 23 18:26:41 merkaba kernel: [137927.147255] btrfs: failed to load free space cache for block group 147131990016 Then there is a long gap where apparently nothing got written onto the root filesystem anymore. Partly due to me using GRML trying to restore things. 1760 Jun 23 19:00:01 merkaba kernel: imklog 5.8.2, log source = /proc/kmsg started. 1761 Jun 23 19:00:01 merkaba rsyslogd: [origin software="rsyslogd" swVersion="5.8.2" x-pid="1342" x-info="http://www.rsyslog.com";] start 1762 Jun 23 19:00:01 merkaba kernel: [ 0.000000] Initializing cgroup subsys cpuset 1763 Jun 23 19:00:01 merkaba kernel: [ 0.000000] Initializing cgroup subsys cpu 1764 Jun 23 19:00:01 merkaba kernel: [ 0.000000] Linux version 3.0.0- rc3-amd64 (Debian 3.0.0~rc3-1~experimental.1) (m...@debian.org) ( gcc version 4.4.6 (Debian 4.4.6-6) ) #1 SMP Thu Jun 16 13:23:22 UTC 2011 Since rsyncing files and movies to two different BTRFS partitions that actually used space_cache I suspect that the failure is related to having the subvolume on the BTRFS filesystem that failed so miserably. As for reproducability: I am now restoring the backup for my external drive to a BTRFS *without* space cache to have my data redundant again. But I did create the subvolume again to see whether the only difference really is the space cache. Lets see how it turns out. Thus I do not like to use this drive for another experiment. But I should have another 60/80 GB 2.5 inch drives here where I could test it. Suspected steps to reproduce: - create BTRFS - mount with compress=lzo,space_cache enabled - umount - mount again only with compress=lzo - create subvolume - rsync stuff to it - issue should appear after some MB of data transferred Ciao, -- Martin 'Helios' Steigerwald - http://www.Lichtvoll.de GPG: 03B0 0D6C 0040 0710 4AFA B82F 991B EAAC A599 84C7 -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
