FIrst, a bit of history of the filesystem: used to be 6 disks, now 5. partially raid1 / raid10. been migrating back and forth a few times. As some point, a balance would not complete and would end with 164 ENOSPC’ses, while there was plenty of unallocated space on each disk. i scanned for extends larger then 1gig and found a few, so ran a recursive balance of the entire FS. I deceided to empty the filesystem and format it. i pulled most files off it some via btrfs send/receive, some via rsync. but 1 subvol wouldn’t send. i don’t remember the exact error, but it was that a extend could not be found on 1 of the disks. with only a few 100gig of data left, i decided to balance some remaining empty space before doing a `btrfs dev del`, so have another disk to store more data on. but im hitting a snag, i hit a BUG_ON when doing a `btrfs bal start -dusage=2 /mountpoint` : [ 3327.678329] btrfs: found 198 extents [ 3328.117274] btrfs: relocating block group 84473084968960 flags 17 [ 3329.278521] btrfs: found 103 extents [ 3331.907931] btrfs: found 103 extents [ 3332.386172] btrfs: relocating block group 84466642518016 flags 17 [ 3333.536595] btrfs: found 86 extents [ 3335.982967] btrfs: found 86 extents [ 3336.599555] btrfs (4746) used greatest stack depth: 2744 bytes left [ 3379.073464] btrfs: relocating block group 89878368419840 flags 17 [ 3381.608948] btrfs: found 499 extents [ 3383.884696] ------------[ cut here ]------------ [ 3383.884720] kernel BUG at fs/btrfs/relocation.c:3405! [ 3383.884731] invalid opcode: 0000 [#1] SMP [ 3383.884742] Modules linked in: [ 3383.884753] CPU: 0 PID: 5663 Comm: btrfs Not tainted 3.13.0 #1 [ 3383.884763] Hardware name: System manufacturer System Product Name/E45M1-I DELUXE, BIOS 0405 08/08/2012 [ 3383.884778] task: ffff8802360eae80 ti: ffff88010dcaa000 task.ti: ffff88010dcaa000 [ 3383.884790] RIP: 0010:[<ffffffff812f0bd5>] [<ffffffff812f0bd5>] __add_tree_block+0x1c5/0x1e0 [ 3383.884811] RSP: 0018:ffff88010dcaba38 EFLAGS: 00010202 [ 3383.884821] RAX: 0000000000000001 RBX: ffff880039f18000 RCX: 00000000ffffffff [ 3383.884832] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 [ 3383.884843] RBP: ffff88010dcaba90 R08: ffff88010dcab9f4 R09: ffff88010dcab930 [ 3383.884854] R10: 0000000000000000 R11: 000000000000047f R12: 0000000000001000 [ 3383.884865] R13: ffff88023489c630 R14: 0000000000000000 R15: 0000528d112e4000 [ 3383.884876] FS: 00007f8e27e74880(0000) GS:ffff88023ec00000(0000) knlGS:0000000000000000 [ 3383.884888] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b [ 3383.884897] CR2: 00007f60d89f35a8 CR3: 00000001b5ada000 CR4: 00000000000007f0 [ 3383.884907] Stack: [ 3383.884941] ffff88010dcabb28 4000ffff812bde34 00a80000528d112e 0000000000000010 [ 3383.885012] 0000000000001000 0000000000001000 0000000000000f3a ffff8802348d6990 [ 3383.885082] ffff88001cbf5a00 ffff880039f18000 00000000000000b8 ffff88010dcabb00 [ 3383.885153] Call Trace: [ 3383.885192] [<ffffffff812f1a54>] add_data_references+0x244/0x2e0 [ 3383.885232] [<ffffffff812f2a2b>] relocate_block_group+0x56b/0x640 [ 3383.885272] [<ffffffff812f2ca2>] btrfs_relocate_block_group+0x1a2/0x2f0 [ 3383.885313] [<ffffffff812cbcca>] btrfs_relocate_chunk.isra.27+0x6a/0x740 [ 3383.885355] [<ffffffff81281a31>] ? btrfs_set_path_blocking+0x31/0x70 [ 3383.885432] [<ffffffff81286816>] ? btrfs_search_slot+0x386/0x960 [ 3383.885473] [<ffffffff812c6f07>] ? free_extent_buffer+0x47/0xa0 [ 3383.885513] [<ffffffff812ceedb>] btrfs_balance+0x90b/0xea0 [ 3383.885553] [<ffffffff812d5ec2>] btrfs_ioctl_balance+0x162/0x520 [ 3383.885592] [<ffffffff812d9aed>] btrfs_ioctl+0xcbd/0x25c0 [ 3383.885632] [<ffffffff818c094c>] ? __do_page_fault+0x1dc/0x520 [ 3383.885673] [<ffffffff81136868>] do_vfs_ioctl+0x2c8/0x490 [ 3383.885712] [<ffffffff81136ab1>] SyS_ioctl+0x81/0xa0 [ 3383.885752] [<ffffffff818c4f5b>] tracesys+0xdd/0xe2 [ 3383.885787] Code: ff 48 8b 4d a8 48 8d 75 b6 4c 89 ea 48 89 df e8 42 e7 ff ff 4c 89 ef 89 45 a8 e8 c7 0f f9 ff 8b 45 a8 e9 69 ff ff ff 85 c0 74 d6 <0f> 0b 66 0f 1f 84 00 00 00 00 00 b8 f4 ff ff ff e9 50 ff ff ff [ 3383.886001] RIP [<ffffffff812f0bd5>] __add_tree_block+0x1c5/0x1e0 [ 3383.886042] RSP <ffff88010dcaba38> [ 3383.886359] ---[ end trace 075209044ce10da3 ]--- Anything i can do to resolve / debug the issue? Remco-- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html