for anybody who gets a panic due to ENOSPC

I still get a kernel panic with both of your patches installed. When I checked with df the file system is about 65% full. But even if it was full it shouldn't cause a kernel panic.

Lee

Nov 17 21:16:50 Intrepid-btrfs kernel: [ 1201.234036] we were searching
for 24576 bytes, num_bytes 24576, loop 2, allowed alloc 1
Nov 17 21:16:50 Intrepid-btrfs kernel: [ 1201.234040] we were searching
for 12288 bytes, num_bytes 12288, loop 2, allowed alloc 1
Nov 17 21:16:50 Intrepid-btrfs kernel: [ 1201.234045] we were searching
for 4096 bytes, num_bytes 4096, loop 2, allowed alloc 1
Nov 17 21:16:50 Intrepid-btrfs kernel: [ 1201.234080] allocation failed
flags 1, wanted 4096
Nov 17 21:16:50 Intrepid-btrfs kernel: [ 1201.234098] space_info has
1580007424 free, is full
Nov 17 21:16:50 Intrepid-btrfs kernel: [ 1201.234134] block group
12582912 has 8388608 bytes, 8380416 used 0 pinned 8192 reserved
Nov 17 21:16:50 Intrepid-btrfs kernel: [ 1201.234172] 0 blocks of free
space at or bigger than bytes is
Nov 17 21:16:50 Intrepid-btrfs kernel: [ 1201.234201] block group
424542208 has 790429696 bytes, 790429696 used 0 pinned 0 reserved
Nov 17 21:16:50 Intrepid-btrfs kernel: [ 1201.234204] 0 blocks of free
space at or bigger than bytes is
Nov 17 21:16:50 Intrepid-btrfs kernel: [ 1201.234206] block group
1214971904 has 790429696 bytes, 790421504 used 0 pinned 8192 reserved
Nov 17 21:16:50 Intrepid-btrfs kernel: [ 1201.234227] 1 blocks of free
space at or bigger than bytes is
Nov 17 21:16:50 Intrepid-btrfs kernel: [ 1201.234230] block group
2005401600 has 790429696 bytes, 0 used 0 pinned 0 reserved
Nov 17 21:16:50 Intrepid-btrfs kernel: [ 1201.234233] 0 blocks of free
space at or bigger than bytes is
Nov 17 21:16:50 Intrepid-btrfs kernel: [ 1201.234235] block group
2795831296 has 790429696 bytes, 851968 used 0 pinned 0 reserved
Nov 17 21:16:50 Intrepid-btrfs kernel: [ 1201.234238] 0 blocks of free
space at or bigger than bytes is
Nov 17 21:16:50 Intrepid-btrfs kernel: [ 1201.234240] block group
3586260992 has 790429696 bytes, 789479424 used 0 pinned 950272 reserved
Nov 17 21:16:50 Intrepid-btrfs kernel: [ 1201.234243] 0 blocks of free
space at or bigger than bytes is
Nov 17 21:16:50 Intrepid-btrfs kernel: [ 1201.234284] block group
4376690688 has 790429696 bytes, 786604032 used 0 pinned 3825664 reserved
Nov 17 21:16:50 Intrepid-btrfs kernel: [ 1201.234287] 0 blocks of free
space at or bigger than bytes is
Nov 17 21:16:50 Intrepid-btrfs kernel: [ 1201.234290] block group
5167120384 has 790429696 bytes, 788373504 used 0 pinned 2056192 reserved
Nov 17 21:16:50 Intrepid-btrfs kernel: [ 1201.234292] 0 blocks of free
space at or bigger than bytes is
Nov 17 21:16:50 Intrepid-btrfs kernel: [ 1201.234295] block group
5957550080 has 790429696 bytes, 789020672 used 0 pinned 1409024 reserved
Nov 17 21:16:50 Intrepid-btrfs kernel: [ 1201.234297] 0 blocks of free
space at or bigger than bytes is
Nov 17 21:16:50 Intrepid-btrfs kernel: [ 1201.234302] block group
6747979776 has 752943104 bytes, 721526784 used 0 pinned 31416320 reserved
Nov 17 21:16:50 Intrepid-btrfs kernel: [ 1201.234305] 0 blocks of free
space at or bigger than bytes is
Nov 17 21:16:50 Intrepid-btrfs kernel: [ 1201.234737] ------------[ cut
here ]------------
Nov 17 21:16:50 Intrepid-btrfs kernel: [ 1201.234760] kernel BUG at
/home/ltrager/btrfs/btrfs-unstable-standalone/extent-tree.c:3088!
Nov 17 21:16:50 Intrepid-btrfs kernel: [ 1201.234796] invalid opcode:
0000 [#1] SMP  
Nov 17 21:16:50 Intrepid-btrfs kernel: [ 1201.234861] Modules linked in:

btrfs zlib_deflate libcrc32c ipv6 af_packet bridge stp bnep rfcomm sco l2cap bluetooth ppdev cpufreq_userspace cpufreq_stats cpufreq_powersave cpufreq_ondemand freq_table cpufreq_conservative wmi video output sbs sbshc pci_slot battery iptable_filter ip_tables x_tables lp evdev psmouse serio_raw pcspkr snd_ens1371 gameport snd_ac97_codec ac97_bus snd_pcm_oss snd_mixer_oss snd_pcm snd_seq_dummy snd_seq_oss snd_seq_midi snd_rawmidi parport_pc snd_seq_midi_event parport snd_seq snd_timer snd_seq_device snd soundcore i2c_piix4 snd_page_alloc container ac button i2c_core shpchp pci_hotplug intel_agp agpgart btrfs mbcache sr_mod cdrom sd_mod crc_t10dif pata_acpi sg ata_piix ehci_hcd uhci_hcd pcnet32 mii ata_generic usbcore mptspi mptscsih mptbase scsi_transport_spi libata scsi_mod dock thermal processor fan fbcon tileblit font bitblit softcursor fuse

Nov 17 21:16:50 Intrepid-btrfs kernel: [ 1201.235013]  
Nov 17 21:16:50 Intrepid-btrfs kernel: [ 1201.235084] Pid: 6150, comm:
bonnie++ Not tainted (2.6.27-7-generic #1)
Nov 17 21:16:50 Intrepid-btrfs kernel: [ 1201.235097] EIP:
0060:[<e0d427b2>] EFLAGS: 00010257 CPU: 0
Nov 17 21:16:50 Intrepid-btrfs kernel: [ 1201.235365] EIP is at
__btrfs_reserve_extent+0x3c2/0x480 [btrfs]
Nov 17 21:16:50 Intrepid-btrfs kernel: [ 1201.235383] EAX: de255464 EBX:
dd4b0300 ECX: ffffffff EDX: 00000001
Nov 17 21:16:50 Intrepid-btrfs kernel: [ 1201.235393] ESI: dd4b032c EDI:
de255458 EBP: ddb03a78 ESP: ddb03a04
Nov 17 21:16:50 Intrepid-btrfs kernel: [ 1201.235403]  DS: 007b ES: 007b
FS: 00d8 GS: 0033 SS: 0068
Nov 17 21:16:50 Intrepid-btrfs kernel: [ 1201.235427] Process bonnie++
(pid: 6150, ti=ddb02000 task=de479920 task.ti=ddb02000)
Nov 17 21:16:50 Intrepid-btrfs kernel: [ 1201.235445] Stack: e0d7fc80
92360000 00000001 2ce10000 00000000 2b01a000 00000000 00000000  
Nov 17 21:16:50 Intrepid-btrfs kernel: [ 1201.235505]        00000000
01df6000 00000000 00000000 00000000 00000000 00000000 00000001  
Nov 17 21:16:50 Intrepid-btrfs kernel: [ 1201.235515]        00000000
00000000 00000000 00000000 00001000 00000000 c8155000 dd076000  
Nov 17 21:16:50 Intrepid-btrfs kernel: [ 1201.235527] Call Trace:
Nov 17 21:16:50 Intrepid-btrfs kernel: [ 1201.235679]  [<e0d42af7>] ?
btrfs_reserve_extent+0x77/0xb0 [btrfs]
Nov 17 21:16:50 Intrepid-btrfs kernel: [ 1201.235986]  [<e0d4fed7>] ?
cow_file_range+0x227/0x4d0 [btrfs]
Nov 17 21:16:50 Intrepid-btrfs kernel: [ 1201.235988]  [<e0d6984c>] ?
lock_extent+0x5c/0xd0 [btrfs]
Nov 17 21:16:50 Intrepid-btrfs kernel: [ 1201.236022]  [<e0d54a30>] ?
run_delalloc_range+0x390/0x400 [btrfs]
Nov 17 21:16:51 Intrepid-btrfs kernel: [ 1201.236037]  [<e0d6ca05>] ?
__extent_writepage+0x4a5/0xb30 [btrfs]
Nov 17 21:16:51 Intrepid-btrfs kernel: [ 1201.236051]  [<e0d6817d>] ?
map_private_extent_buffer+0x8d/0x120 [btrfs]
Nov 17 21:16:51 Intrepid-btrfs kernel: [ 1201.236069]  [<c019339e>] ?
page_address+0xe/0xe0
Nov 17 21:16:51 Intrepid-btrfs kernel: [ 1201.236069]  [<c019339e>] ?
page_address+0xe/0xe0
Nov 17 21:16:51 Intrepid-btrfs kernel: [ 1201.236069]  [<c011fd28>] ?
kmap_atomic_prot+0x48/0x100
Nov 17 21:16:51 Intrepid-btrfs kernel: [ 1201.236069]  [<c0250d2d>] ?
radix_tree_gang_lookup_tag_slot+0x9d/0xc0
Nov 17 21:16:51 Intrepid-btrfs kernel: [ 1201.236069]  [<c018409d>] ?
find_get_pages_tag+0x3d/0x130
Nov 17 21:16:51 Intrepid-btrfs kernel: [ 1201.236069]  [<c019d0ce>] ?
page_mkclean+0xe/0xb0
Nov 17 21:16:51 Intrepid-btrfs kernel: [ 1201.236069]  [<c01917f6>] ?
__dec_zone_state+0x16/0x90
Nov 17 21:16:51 Intrepid-btrfs kernel: [ 1201.236069]  [<e0d693ad>] ?
extent_write_cache_pages+0x1ad/0x2f0 [btrfs]
Nov 17 21:16:51 Intrepid-btrfs kernel: [ 1201.236069]  [<e0d4f370>] ?
btrfs_writepages+0x0/0x30 [btrfs]
Nov 17 21:16:51 Intrepid-btrfs kernel: [ 1201.236069]  [<e0d69526>] ?
extent_writepages+0x36/0x60 [btrfs]
Nov 17 21:16:51 Intrepid-btrfs kernel: [ 1201.236069]  [<e0d6c560>] ?
__extent_writepage+0x0/0xb30 [btrfs]
Nov 17 21:16:51 Intrepid-btrfs kernel: [ 1201.236069]  [<e0d55230>] ?
btrfs_get_extent+0x0/0xad0 [btrfs]
Nov 17 21:16:51 Intrepid-btrfs kernel: [ 1201.236069]  [<e0d4f394>] ?
btrfs_writepages+0x24/0x30 [btrfs]
Nov 17 21:16:51 Intrepid-btrfs kernel: [ 1201.236069]  [<c018c4a3>] ?
do_writepages+0x33/0x60
Nov 17 21:16:51 Intrepid-btrfs kernel: [ 1201.236069]  [<c01d25dc>] ?
__sync_single_inode+0x5c/0x250
Nov 17 21:16:51 Intrepid-btrfs kernel: [ 1201.236069]  [<c01d281a>] ?
__writeback_single_inode+0x4a/0x160
Nov 17 21:16:51 Intrepid-btrfs kernel: [ 1201.236069]  [<c024febc>] ?
prop_fraction_single+0x3c/0x70
Nov 17 21:16:51 Intrepid-btrfs kernel: [ 1201.236069]  [<c01d2ccc>] ?
generic_sync_sb_inodes+0x27c/0x3b0
Nov 17 21:16:51 Intrepid-btrfs kernel: [ 1201.236069]  [<c01d306d>] ?
writeback_inodes+0x4d/0xe0
Nov 17 21:16:51 Intrepid-btrfs kernel: [ 1201.236069]  [<c018bd18>] ?
balance_dirty_pages+0x238/0x340
Nov 17 21:16:51 Intrepid-btrfs kernel: [ 1201.236069]  [<c018be84>] ?
balance_dirty_pages_ratelimited_nr+0x64/0x70
Nov 17 21:16:51 Intrepid-btrfs kernel: [ 1201.236069]  [<e0d5a51d>] ?
btrfs_file_write+0x3dd/0x6a0 [btrfs]
Nov 17 21:16:51 Intrepid-btrfs kernel: [ 1201.236069]  [<c02353be>] ?
apparmor_file_permission+0x1e/0x40
Nov 17 21:16:51 Intrepid-btrfs kernel: [ 1201.236069]  [<c01b1fad>] ?
rw_verify_area+0x4d/0xc0
Nov 17 21:16:51 Intrepid-btrfs kernel: [ 1201.236069]  [<c01b1764>] ?
generic_file_llseek_unlocked+0x14/0xb0
Nov 17 21:16:51 Intrepid-btrfs kernel: [ 1201.236069]  [<c01b24c0>] ?
vfs_write+0xa0/0x110
Nov 17 21:16:51 Intrepid-btrfs kernel: [ 1201.236069]  [<e0d5a140>] ?
btrfs_file_write+0x0/0x6a0 [btrfs]
Nov 17 21:16:51 Intrepid-btrfs kernel: [ 1201.236069]  [<c01b2602>] ?
sys_write+0x42/0x70
Nov 17 21:16:51 Intrepid-btrfs kernel: [ 1201.236069]  [<c0103f7b>] ?
sysenter_do_call+0x12/0x2f
Nov 17 21:16:51 Intrepid-btrfs kernel: [ 1201.236069] 
=======================
Nov 17 21:16:51 Intrepid-btrfs kernel: [ 1201.236069] Code: 9c 63 df 8d
4b 44 89 c8 89 4d f0 e8 99 b1 63 df 8b 7b 38 8b 07 0f 18 00 90 83 c3 38
39 fb 89 5d ec 75 33 8b 45 f0 e8 5e 92 40 df <0f> 0b eb fe 66 90 8b 90
90 18 00 00 8b 88 78 18 00 00 8b b0 8c  
Nov 17 21:16:51 Intrepid-btrfs kernel: [ 1201.236069] EIP: [<e0d427b2>]
__btrfs_reserve_extent+0x3c2/0x480 [btrfs] SS:ESP 0068:ddb03a04
Nov 17 21:16:51 Intrepid-btrfs kernel: [ 1201.236886] ---[ end trace

db9e9518b4387879 ]---

I've generated another allocation error with the debugging patch installed.

In order to get a better idea of disk usage around the period of the allocation errors, I made up a bash script to dump 'df -T /var/tmp/portage' every 3 seconds to the terminal (where my btrfs drive is mounted at /var/tmp/portage) until 20 polls after dmesg goes over 20 lines in length.

For this error, max usage was shown as:
Filesystem Type 1K-blocks Used Available Use% Mounted on
/dev/sdc2 btrfs 3510200 890424 2619776 26% /var/tmp/portage

The dmesg output did show '[ 4171.126131] space_info has 0 free, is full', but this did not agree with the 'df -T' output. Let me know if you can think of something else I should be looking at here.

My test partition is ~3.3-3.4 GB (3,510,200 1K blocks). I am mounting btrfs with compression turned on.

The drive is 10 GB total, so I can increase size, but I'm trying to select a size to highlight problems. Let me know if you'd like to test some other sizes.

Here's a summary of usage for this drive:
(1) Create drive 'mkfs.btrfs'
(2) Fill Drive to ~66% by uncompressing the FlightGear source package multiple times.
(3) Delete all files using 'rm -rf' (I was wondering if there was a repeatable problem with this kind of operation, but it worked fine. No errors to this point, and the drive indicated near-empty after this (~300k still allocated)).
(4) Beginning compiling Open Office with Gentoo Portage build manager (portage uses /var/tmp/portage as a build directory).

During the OpenOffice build process, the build crashed in conjunction with the following dmesg output:

[ 4171.126120] we were searching for 4096 bytes, num_bytes 4096, loop
2, allowed_alloc 1
[ 4171.126129] allocation failed flags 36, wanted 4096
[ 4171.126131] space_info has 0 free, is full
[ 4171.126523] block group 29360128 has 179699712 bytes, 167817216
used 11882496 pinned 0 reserved
[ 4171.126528] 0 blocks of free space at or bigger than bytes is
[ 4171.126582] ------------[ cut here ]------------
[ 4171.126585] kernel BUG at
/var/tmp/portage/sys-fs/btrfs-9998/work/btrfs-9998/extent-tree.c:3088!
[ 4171.126587] invalid opcode: 0000 [#1]
[ 4171.126589] Modules linked in: btrfs snd_pcm_oss snd_mixer_oss

snd_seq_dummy snd_seq_oss snd_seq_midi_event snd_seq snd_seq_device ipv6 ppdev pcspkr nvidia(P) snd_intel8x0 snd_ac97_codec ac97_bus snd_pcm snd_timer snd snd_page_alloc forcedeth ohci_hcd i2c_nforce2 ssb pcmcia i2c_core parport_pc parport nvidia_agp sr_mod scsi_wait_scan sl811_hcd uhci_hcd ehci_hcd

[ 4171.126606]
[ 4171.126610] Pid: 1227, comm: find Tainted: P          (2.6.27-sabayon-r10 #1)
[ 4171.126613] EIP: 0060:[<f8e2f23e>] EFLAGS: 00210257 CPU: 0
[ 4171.126650] EIP is at __btrfs_reserve_extent+0x2be/0x430 [btrfs]
[ 4171.126653] EAX: ed75c940 EBX: f1e1b180 ECX: f4ea28a0 EDX: 00000001
[ 4171.126656] ESI: ed75c938 EDI: ed75c938 EBP: ed75c940 ESP: e4447c48
[ 4171.126658]  DS: 007b ES: 007b FS: 0000 GS: 0033 SS: 0068
[ 4171.126661] Process find (pid: 1227, ti=e4446000 task=f4ea28a0
task.ti=e4446000)
[ 4171.126663] Stack: f8e6d944 01c00000 00000000 0ab60000 00000000
0a00b000 00000000 00b55000
[ 4171.126668]        00000000 00000000 00000000 00000000 00000000
00000000 00000000 00000024
[ 4171.126672]        0c75dfff 00000000 ed684e00 f20f9078 ed618000
00000005 00000000 ed684e00
[ 4171.126677] Call Trace:
[ 4171.126680]  [<f8e2f89f>] btrfs_alloc_extent+0x9f/0x140 [btrfs]
[ 4171.126700]  [<f8e2fa0e>] btrfs_alloc_free_block+0xce/0x110 [btrfs]
[ 4171.126718]  [<f8e242e9>] __btrfs_cow_block+0x219/0x870 [btrfs]
[ 4171.126737]  [<f8e392c2>] verify_parent_transid+0x62/0x1a0 [btrfs]
[ 4171.126755]  [<f8e24fec>] btrfs_cow_block+0x13c/0x1e0 [btrfs]
[ 4171.126773]  [<f8e28190>] btrfs_search_slot+0x1c0/0x7f0 [btrfs]
[ 4171.126791]  [<f8e5690c>] map_private_extent_buffer+0x8c/0x140 [btrfs]
[ 4171.126814]  [<c0195aa0>] path_walk+0x50/0x90
[ 4171.126822]  [<f8e38aac>] btrfs_lookup_inode+0x3c/0xc0 [btrfs]
[ 4171.126841]  [<f8e42906>] btrfs_update_inode+0x46/0xc0 [btrfs]
[ 4171.126861]  [<f8e43a7f>] btrfs_dirty_inode+0x3f/0x60 [btrfs]
[ 4171.126881]  [<c01a8c90>] __mark_inode_dirty+0x30/0x160
[ 4171.126887]  [<c0197f90>] filldir64+0x0/0xe0
[ 4171.126890]  [<c019f837>] touch_atime+0xc7/0xf0
[ 4171.126896]  [<c01981f6>] vfs_readdir+0xa6/0xb0
[ 4171.126898]  [<c019826f>] sys_getdents64+0x6f/0xc0
[ 4171.126901]  [<c010303d>] sysenter_do_call+0x12/0x21
[ 4171.126906]  =======================
[ 4171.126908] Code: 89 44 24 04 e8 f4 e8 2e c7 89 d8 8b 54 24 68 8b
4c 24 6c e8 c5 bf 03 00 8b 36 8b 06 0f 18 00 90 39 fe 75 90 89 e8 e8
82 29 30 c7 <0f> 0b eb fe 8b 5c 24 48 8b 74 24 50 8b 83 f4 00 00 00 8b
50 20
[ 4171.126927] EIP: [<f8e2f23e>] __btrfs_reserve_extent+0x2be/0x430
[btrfs] SS:ESP 0068:e4447c48
[ 4171.126947] ---[ end trace 91e641b298e7b0de ]---
[ 4171.129768] we were searching for 4096 bytes, num_bytes 4096, loop
2, allowed_alloc 1
[ 4171.129774] allocation failed flags 36, wanted 4096
[ 4171.129777] space_info has 0 free, is full
[ 4171.129779] block group 29360128 has 179699712 bytes, 167817216
used 11882496 pinned 0 reserved
[ 4171.129782] 0 blocks of free space at or bigger than bytes is
[ 4171.129817] ------------[ cut here ]------------
[ 4171.129819] kernel BUG at
/var/tmp/portage/sys-fs/btrfs-9998/work/btrfs-9998/extent-tree.c:3088!
[ 4171.129822] invalid opcode: 0000 [#2]
[ 4171.129824] Modules linked in: btrfs snd_pcm_oss snd_mixer_oss

snd_seq_dummy snd_seq_oss snd_seq_midi_event snd_seq snd_seq_device ipv6 ppdev pcspkr nvidia(P) snd_intel8x0 snd_ac97_codec ac97_bus snd_pcm snd_timer snd snd_page_alloc forcedeth ohci_hcd i2c_nforce2 ssb pcmcia i2c_core parport_pc parport nvidia_agp sr_mod scsi_wait_scan sl811_hcd uhci_hcd ehci_hcd

[ 4171.129840]
[ 4171.129843] Pid: 30919, comm: localize-ooo Tainted: P      D
(2.6.27-sabayon-r10 #1)
[ 4171.129846] EIP: 0060:[<f8e2f23e>] EFLAGS: 00210257 CPU: 0
[ 4171.129874] EIP is at __btrfs_reserve_extent+0x2be/0x430 [btrfs]
[ 4171.129876] EAX: ed75c940 EBX: f1e1b180 ECX: f4ea2080 EDX: 00000001
[ 4171.129879] ESI: ed75c938 EDI: ed75c938 EBP: ed75c940 ESP: e93c7b2c
[ 4171.129881]  DS: 007b ES: 007b FS: 0000 GS: 0033 SS: 0068
[ 4171.129884] Process localize-ooo (pid: 30919, ti=e93c6000
task=f4ea2080 task.ti=e93c6000)
[ 4171.129886] Stack: f8e6d944 01c00000 00000000 0ab60000 00000000
0a00b000 00000000 00b55000
[ 4171.129891]        00000000 00000000 00000000 00000000 00000000
00000000 00000000 00000024
[ 4171.129895]        c0133b7e 00000000 ed684e00 f20f9028 ed618000
00000005 00000000 ed684e00
[ 4171.129900] Call Trace:
[ 4171.129902]  [<c0133b7e>] update_wall_time+0x25e/0x7f0
[ 4171.129911]  [<f8e2f89f>] btrfs_alloc_extent+0x9f/0x140 [btrfs]
[ 4171.129930]  [<f8e2fa0e>] btrfs_alloc_free_block+0xce/0x110 [btrfs]
[ 4171.129949]  [<f8e242e9>] __btrfs_cow_block+0x219/0x870 [btrfs]
[ 4171.129967]  [<f8e392c2>] verify_parent_transid+0x62/0x1a0 [btrfs]
[ 4171.129985]  [<f8e24fec>] btrfs_cow_block+0x13c/0x1e0 [btrfs]
[ 4171.130003]  [<f8e28190>] btrfs_search_slot+0x1c0/0x7f0 [btrfs]
[ 4171.130010]  [<c0172735>] do_wp_page+0x315/0x4e0
[ 4171.130010]  [<f8e38aac>] btrfs_lookup_inode+0x3c/0xc0 [btrfs]
[ 4171.130010]  [<c011a819>] check_preempt_wakeup+0xe9/0x140
[ 4171.130010]  [<f8e42906>] btrfs_update_inode+0x46/0xc0 [btrfs]
[ 4171.130010]  [<f8e43a7f>] btrfs_dirty_inode+0x3f/0x60 [btrfs]
[ 4171.130010]  [<c01a8c90>] __mark_inode_dirty+0x30/0x160
[ 4171.130010]  [<c019f837>] touch_atime+0xc7/0xf0
[ 4171.130010]  [<c0165e9f>] generic_file_aio_read+0x56f/0x5f0
[ 4171.130010]  [<c018c275>] do_sync_read+0xd5/0x120
[ 4171.130010]  [<c010264a>] do_notify_resume+0x37a/0x750
[ 4171.130010]  [<c012e610>] autoremove_wake_function+0x0/0x40
[ 4171.130010]  [<c041c64c>] security_file_permission+0xc/0x10
[ 4171.130010]  [<c018c31e>] rw_verify_area+0x5e/0xd0
[ 4171.130010]  [<c018c1a0>] do_sync_read+0x0/0x120
[ 4171.130010]  [<c018cbad>] vfs_read+0x9d/0x160
[ 4171.130010]  [<c018cf01>] sys_read+0x41/0x70
[ 4171.130010]  [<c010303d>] sysenter_do_call+0x12/0x21
[ 4171.130010]  =======================
[ 4171.130010] Code: 89 44 24 04 e8 f4 e8 2e c7 89 d8 8b 54 24 68 8b
4c 24 6c e8 c5 bf 03 00 8b 36 8b 06 0f 18 00 90 39 fe 75 90 89 e8 e8
82 29 30 c7 <0f> 0b eb fe 8b 5c 24 48 8b 74 24 50 8b 83 f4 00 00 00 8b
50 20
[ 4171.130010] EIP: [<f8e2f23e>] __btrfs_reserve_extent+0x2be/0x430
[btrfs] SS:ESP 0068:e93c7b2c
[ 4171.130201] ---[ end trace 91e641b298e7b0de ]---

Some Follow-Up:

Just to ease my mind, I ran 7 iterations of a destructive badblocks test on the partition I've been using without error ('badblocks -sw -t random -p 7 /dev/sdc2').

Hrm this is frustrating, I can't figure out whats going wrong and I can't reproduce this here, I just keep hitting a reall ENOSPC. Please run with this patch and send me the output. Thanks much,

Josef

index 6eb56a0..a24e368 100644
@@ -2898,6 +2898,18 @@ static int noinline find_free_extent(struct btrfs_trans_handle *trans,
 			break;
 		}
 new_group:
+		if (loop == 2) {
+			spin_lock(&block_group->lock);
+			printk(KERN_ERR "block_group %Lu didn't have what we "
+			       "needed.  %Lu total, %Lu used, %Lu pinned, %Lu "
+			       "reserved.  Dumping free space\n",
+			       block_group->key.objectid,
+			       block_group->key.offset,
+			       btrfs_block_group_used(&block_group->item),
+			       block_group->pinned, block_group->reserved);
+			spin_unlock(&block_group->lock);
+			btrfs_dump_free_space(block_group, 0);
+		}
 		mutex_unlock(&block_group->alloc_mutex);
 new_group_no_lock:
 		/* don't try to compare new allocations against the

index f4926c0..3699656 100644
@@ -402,8 +402,8 @@ void btrfs_dump_free_space(struct btrfs_block_group_cache *block_group,
 		info = rb_entry(n, struct btrfs_free_space, offset_index);
 		if (info->bytes >= bytes)
 			count++;
-		//printk(KERN_INFO "offset=%Lu, bytes=%Lu\n", info->offset,
-		//       info->bytes);
+		printk(KERN_INFO "offset=%Lu, bytes=%Lu\n", info->offset,
+		       info->bytes);
 	}
 	printk(KERN_INFO "%d blocks of free space at or bigger than bytes is"
 	       "\n", count);

Sorry it took so long to reply it took awhile to run this test. It
didn't cause a kernel panic for about 8 hours. df says only 623M of the
available 7539M are used. Anyway this is with the latest checkin by Chris Mason with the patch you sent me.

Also since you said you cann't reproduce this I thought it might be helpful to know the environment I'm doing testing on. I have been running bonnie++ on xubuntu 8.10 fully updated on vmware 6.5. No vmware tools are instead except for the mouse and video xorg drivers which come by default with ubuntu. I have two 8G prealloced virtual drives. The first one is where the xubuntu install is using ext2 for /boot and / and has a 512M swap partition. The second one is where I do all of the btrfs testing. I have it partitioned because I was experimenting with booting with btrfs as root so the partition btrfs is on has 7539M. The VM has 512M of RAM dedicated to it and is using one core of my Intel Core 2 Duo T7500 running at 2.2GHz.

Lee

...

[ 7133.346381] block_group 5167120384 didn't have what we needed. 790429696 total, 383414272 used, 407011328 pinned, 4096 reserved. Dumping free space
[ 7133.346385] 0 blocks of free space at or bigger than bytes is
[ 7133.346388] block_group 5957550080 didn't have what we needed. 790429696 total, 1011712 used, 789413888 pinned, 4096 reserved. Dumping free space
[ 7133.346391] 0 blocks of free space at or bigger than bytes is
[ 7133.346394] block_group 6747979776 didn't have what we needed. 752943104 total, 125444096 used, 627499008 pinned, 0 reserved. Dumping free space
[ 7133.346397] 0 blocks of free space at or bigger than bytes is
[ 7133.346400] we were searching for 4096 bytes, num_bytes 4096, loop 2, allowed_alloc 1
[ 7133.346403] allocation failed flags 1, wanted 4096
[ 7133.346405] space_info has 1064009728 free, is full
[ 7133.346408] block group 12582912 has 8388608 bytes, 516096 used 7872512 pinned 0 reserved
[ 7133.346410] 0 blocks of free space at or bigger than bytes is
[ 7133.346413] block group 424542208 has 790429696 bytes, 2105344 used 788324352 pinned 0 reserved
[ 7133.346416] offset=1214971904, bytes=274759680
[ 7133.346417] 1 blocks of free space at or bigger than bytes is
[ 7133.346420] block group 1214971904 has 790429696 bytes, 3964928 used 511705088 pinned 0 reserved
[ 7133.346423] 0 blocks of free space at or bigger than bytes is
[ 7133.346425] block group 2005401600 has 790429696 bytes, 1490944 used 788938752 pinned 0 reserved
[ 7133.346428] offset=2795831296, bytes=789250048
[ 7133.346430] 1 blocks of free space at or bigger than bytes is
[ 7133.346432] block group 2795831296 has 790429696 bytes, 1179648 used 0 pinned 0 reserved
[ 7133.346435] 0 blocks of free space at or bigger than bytes is
[ 7133.346438] block group 3586260992 has 790429696 bytes, 1392640 used 789037056 pinned 0 reserved
[ 7133.346440] 0 blocks of free space at or bigger than bytes is
[ 7133.346443] block group 4376690688 has 790429696 bytes, 128237568 used 662192128 pinned 0 reserved
[ 7133.346445] 0 blocks of free space at or bigger than bytes is
[ 7133.346448] block group 5167120384 has 790429696 bytes, 383414272 used 407011328 pinned 4096 reserved
[ 7133.346451] 0 blocks of free space at or bigger than bytes is
[ 7133.346453] block group 5957550080 has 790429696 bytes, 1011712 used 789413888 pinned 4096 reserved
[ 7133.346456] 0 blocks of free space at or bigger than bytes is
[ 7133.346458] block group 6747979776 has 752943104 bytes, 125444096 used 627499008 pinned 0 reserved
[ 7133.346461] 0 blocks of free space at or bigger than bytes is
[ 7133.346490] ------------[ cut here ]------------
[ 7133.346493] kernel BUG at /home/ltrager/btrfs/btrfs-unstable-standalone/extent-tree.c:3101!
[ 7133.346499] invalid opcode: 0000 [#309] SMP 
[ 7133.346502] Modules linked in: btrfs zlib_deflate libcrc32c ipv6 af_packet bridge stp rfcomm bnep sco l2cap bluetooth ppdev cpufreq_userspace cpufreq_stats cpufreq_powersave cpufreq_ondemand freq_table cpufreq_conservative wmi video output sbs sbshc pci_slot battery iptable_filter ip_tables x_tables lp evdev psmouse serio_raw pcspkr snd_ens1371 gameport snd_ac97_codec ac97_bus snd_pcm_oss snd_mixer_oss snd_pcm snd_seq_dummy snd_seq_oss snd_seq_midi snd_rawmidi snd_seq_midi_event snd_seq snd_timer snd_seq_device snd soundcore snd_page_alloc parport_pc parport i2c_piix4 i2c_core container ac intel_agp button shpchp pci_hotplug agpgart ext2 mbcache sr_mod cdrom sd_mod crc_t10dif pata_acpi sg ata_piix uhci_hcd ehci_hcd usbcore ata_generic pcnet32 mii mptspi mptscsih mptbase scsi_transport_s
 pi libata scsi_mod dock thermal processor fan fbcon tileblit font bitblit softcursor fuse
[ 7133.346570] 
[ 7133.346573] Pid: 6575, comm: bonnie++ Tainted: G      D   (2.6.27-7-generic #1)
[ 7133.346576] EIP: 0060:[<e0d3944a>] EFLAGS: 00210257 CPU: 0
[ 7133.346591] EIP is at __btrfs_reserve_extent+0x36a/0x420 [btrfs]
[ 7133.346594] EAX: ddce128c EBX: ddce3cc0 ECX: ffffffff EDX: 00000001
[ 7133.346597] ESI: ddce3cec EDI: ddce1280 EBP: d779da78 ESP: d779da04
[ 7133.346599]  DS: 007b ES: 007b FS: 00d8 GS: 0033 SS: 0068
[ 7133.346602] Process bonnie++ (pid: 6575, ti=d779c000 task=de6e57f0 task.ti=d779c000)
[ 7133.346605] Stack: e0d78f44 92360000 00000001 2ce10000 00000000 077a2000 00000000 2566e000 
[ 7133.346612]        00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000001 
[ 7133.346618]        00000000 00000000 00000000 00000000 00001000 00000000 ded19050 dd046000 
[ 7133.346625] Call Trace:
[ 7133.346629]  [<e0d39577>] ? btrfs_reserve_extent+0x77/0xb0 [btrfs]
[ 7133.346645]  [<e0d473a7>] ? cow_file_range+0x227/0x4d0 [btrfs]
[ 7133.346661]  [<e0d60df9>] ? lock_delalloc_pages+0xd9/0x180 [btrfs]
[ 7133.346676]  [<e0d614ec>] ? lock_extent+0x5c/0xd0 [btrfs]
[ 7133.346690]  [<e0d4c100>] ? run_delalloc_range+0x390/0x400 [btrfs]
[ 7133.346706]  [<e0d646a5>] ? __extent_writepage+0x4a5/0xb30 [btrfs]
[ 7133.346747]  [<c019339e>] ? page_address+0xe/0xe0
[ 7133.346754]  [<c019339e>] ? page_address+0xe/0xe0
[ 7133.346758]  [<c011fd28>] ? kmap_atomic_prot+0x48/0x100
[ 7133.346764]  [<c0250d2d>] ? radix_tree_gang_lookup_tag_slot+0x9d/0xc0
[ 7133.346770]  [<c018409d>] ? find_get_pages_tag+0x3d/0x130
[ 7133.346775]  [<c019d0ce>] ? page_mkclean+0xe/0xb0
[ 7133.346780]  [<c01917f6>] ? __dec_zone_state+0x16/0x90
[ 7133.346786]  [<e0d6104d>] ? extent_write_cache_pages+0x1ad/0x2f0 [btrfs]
[ 7133.346802]  [<e0d46840>] ? btrfs_writepages+0x0/0x30 [btrfs]
[ 7133.346819]  [<e0d611c6>] ? extent_writepages+0x36/0x60 [btrfs]
[ 7133.346834]  [<e0d64200>] ? __extent_writepage+0x0/0xb30 [btrfs]
[ 7133.346849]  [<e0d4c900>] ? btrfs_get_extent+0x0/0xad0 [btrfs]
[ 7133.346866]  [<e0d46864>] ? btrfs_writepages+0x24/0x30 [btrfs]
[ 7133.346881]  [<c018c4a3>] ? do_writepages+0x33/0x60
[ 7133.346886]  [<c01d25dc>] ? __sync_single_inode+0x5c/0x250
[ 7133.346891]  [<c01d281a>] ? __writeback_single_inode+0x4a/0x160
[ 7133.346895]  [<c024febc>] ? prop_fraction_single+0x3c/0x70
[ 7133.346900]  [<c01d2ccc>] ? generic_sync_sb_inodes+0x27c/0x3b0
[ 7133.346905]  [<c01d306d>] ? writeback_inodes+0x4d/0xe0
[ 7133.346909]  [<c018bd18>] ? balance_dirty_pages+0x238/0x340
[ 7133.346914]  [<c018be84>] ? balance_dirty_pages_ratelimited_nr+0x64/0x70
[ 7133.346919]  [<e0d51a8d>] ? btrfs_file_write+0x3dd/0x6a0 [btrfs]
[ 7133.346936]  [<c02353be>] ? apparmor_file_permission+0x1e/0x40
[ 7133.346942]  [<c01b1fad>] ? rw_verify_area+0x4d/0xc0
[ 7133.346947]  [<c01b1ac2>] ? fsnotify_modify+0x72/0x80
[ 7133.346951]  [<c01b24c0>] ? vfs_write+0xa0/0x110
[ 7133.346955]  [<e0d516b0>] ? btrfs_file_write+0x0/0x6a0 [btrfs]
[ 7133.346972]  [<c01b2602>] ? sys_write+0x42/0x70
[ 7133.346976]  [<c0103f7b>] ? sysenter_do_call+0x12/0x2f
[ 7133.346981]  =======================
[ 7133.346983] Code: 2f 64 df 8d 4b 4c 89 c8 89 4d f0 e8 01 45 64 df 8b 7b 40 8b 07 0f 18 00 90 83 c3 40 39 fb 89 5d ec 75 33 8b 45 f0 e8 c6 25 41 df <0f> 0b eb fe 66 90 8b 90 c4 18 00 00 8b 88 ac 18 00 00 8b b0 c0 
[ 7133.347025] EIP: [<e0d3944a>] __btrfs_reserve_extent+0x36a/0x420 [btrfs] SS:ESP 0068:d779da04
[ 7133.347042] ---[ end trace 97493f65cf117b85 ]---

Ok this is almost everything I need, I just need a few more lines of the debug output, so all of this plus lets say the last 100 lines, that should be everything I need. Or if you have full logs that you can post somewhere that would be great and I can filter through them myself. Thanks much for testing this stuff for me,

Josef