Bug 104821 - btrfsck assertion: "Unable to find block group for 0" "extent-tree.c:289: find_search_start: Assertion `1` failed."
Summary: btrfsck assertion: "Unable to find block group for 0" "extent-tree.c:289: fin...
Status: NEW
Alias: None
Product: File System
Classification: Unclassified
Component: btrfs (show other bugs)
Hardware: All Linux
: P1 normal
Assignee: Josef Bacik
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2015-09-20 17:27 UTC by g2p.code+kbugs
Modified: 2017-01-14 12:11 UTC (History)
2 users (show)

See Also:
Kernel Version: 4.2
Tree: Mainline
Regression: No


Attachments

Description g2p.code+kbugs 2015-09-20 17:27:22 UTC
Running btrfsck or btrfstune -n in gdb

break exit

In find_search_start:

print *root
$8 = {node = 0x6c0a60, commit_root = 0x0, root_item = {inode = {generation = 1, transid = 0, size = 3, nbytes = 16384, block_group = 0, nlink = 1, uid = 0, gid = 0, mode = 16877, 
      rdev = 0, flags = 0, sequence = 0, reserved = {0, 0, 0, 0}, atime = {sec = 0, nsec = 0}, ctime = {sec = 0, nsec = 0}, mtime = {sec = 0, nsec = 0}, otime = {sec = 0, nsec = 0}}, 
    generation = 22117, root_dirid = 0, bytenr = 3022880899072, byte_limit = 0, bytes_used = 720502784, last_snapshot = 0, flags = 0, refs = 1, drop_progress = {objectid = 0, 
      type = 0 '\000', offset = 0}, drop_level = 0 '\000', level = 2 '\002', generation_v2 = 22117, uuid = "\362\247hPx\244,C\214B\213Z\"ZE\n", 
    parent_uuid = '\000' <15 times>, 
    received_uuid = '\000' <15 times>, ctransid = 0, otransid = 0, stransid = 0, rtransid = 0, ctime = {sec = 0, 
      nsec = 0}, otime = {sec = 0, nsec = 0}, stime = {sec = 0, nsec = 0}, rtime = {sec = 0, nsec = 0}, reserved = {0, 0, 0, 0, 0, 0, 0, 0}}, root_key = {objectid = 2, 
    type = 132 '\204', offset = 0}, fs_info = 0x66de30, objectid = 2, last_trans = 0, sectorsize = 4096, nodesize = 16384, leafsize = 16384, stripesize = 4096, ref_cows = 0, 
  track_dirty = 1, type = 0, highest_inode = 0, last_inode_alloc = 0, orphan_data_extents = {next = 0x66e500, prev = 0x66e500}, dirty_list = {next = 0x66e510, prev = 0x66e510}, 
  rb_node = {__rb_parent_color = 0, rb_right = 0x0, rb_left = 0x0}}
print num
$9 = 16384
print data
$10 = 52

Is there a way to skip this assertion / the bad node?
The filesystem appears functional at runtime, although scrub finds checksum errors on some data.
Tell me if a btrfs-image is necessary, but it will most likely be very large.
Comment 1 g2p.code+kbugs 2015-09-22 01:28:22 UTC
It seems this was caused by an incomplete balance.
Comment 2 Lars 2017-01-14 12:03:21 UTC
Hi,

I am getting the same error and my filesystem is not mountable.

---------------------
[root@localhost ~]# btrfs rescue zero-log /dev/sdd4
fsid mismatch, want=57e1b36b-23ad-42fb-bbaa-47931689f2c0, have=8706dcfe-2bb5-4d33-a52f-f3f5c69da371
Clearing log on /dev/sdd4, previous log_root 0, level 0
fsid mismatch, want=57e1b36b-23ad-42fb-bbaa-47931689f2c0, have=8706dcfe-2bb5-4d33-a52f-f3f5c69da371
parent transid verify failed on 341939830784 wanted 97583 found 95622
parent transid verify failed on 341939830784 wanted 97583 found 95622
parent transid verify failed on 341939830784 wanted 97583 found 95622
parent transid verify failed on 341939830784 wanted 97583 found 95622
Ignoring transid failure
parent transid verify failed on 336458514432 wanted 98995 found 95609
parent transid verify failed on 336458514432 wanted 98995 found 95609
parent transid verify failed on 336458514432 wanted 98995 found 95609
parent transid verify failed on 336458514432 wanted 98995 found 95609
Ignoring transid failure
fsid mismatch, want=57e1b36b-23ad-42fb-bbaa-47931689f2c0, have=8706dcfe-2bb5-4d33-a52f-f3f5c69da371
fsid mismatch, want=57e1b36b-23ad-42fb-bbaa-47931689f2c0, have=8706dcfe-2bb5-4d33-a52f-f3f5c69da371
fsid mismatch, want=57e1b36b-23ad-42fb-bbaa-47931689f2c0, have=8706dcfe-2bb5-4d33-a52f-f3f5c69da371
Unable to find block group for 0
extent-tree.c:289: find_search_start: Assertion `1` failed.
btrfs(+0x4e8ba)[0x55cc7f7ef8ba]
btrfs(btrfs_reserve_extent+0xa3f)[0x55cc7f7f481f]
btrfs(btrfs_alloc_free_block+0x5f)[0x55cc7f7f48ef]
btrfs(__btrfs_cow_block+0xc4)[0x55cc7f7e5854]
btrfs(btrfs_cow_block+0x35)[0x55cc7f7e5e55]
btrfs(+0x4a3a6)[0x55cc7f7eb3a6]
btrfs(btrfs_commit_transaction+0x95)[0x55cc7f7ed1d5]
btrfs(+0x37e29)[0x55cc7f7d8e29]
btrfs(main+0x7b)[0x55cc7f7b0ddb]
/lib64/libc.so.6(__libc_start_main+0xf1)[0x7ff89d796401]
btrfs(_start+0x2a)[0x55cc7f7b0eea]
---------------------

This is a raid 10
-------------
[root@localhost ~]# btrfs filesystem show
Label: 'fedora'  uuid: 57e1b36b-23ad-42fb-bbaa-47931689f2c0
	Total devices 4 FS bytes used 291.76GiB
	devid    1 size 2.72TiB used 148.03GiB path /dev/sdd4
	devid    2 size 2.72TiB used 148.03GiB path /dev/sda4
	devid    3 size 2.72TiB used 148.03GiB path /dev/sdb4
	devid    4 size 2.72TiB used 148.03GiB path /dev/sdc4
----------------


I had a disk break down, which I successfully replaced and the fs was apparantly rebalanced correctly. At the same time I noticed that two more disks were showing errors in smart. Two days later my motherboard died. Now I am trying to get the filesystem mounted after puttting in a new motherboard.
Comment 3 Lars 2017-01-14 12:09:37 UTC
Linux localhost-live 4.8.6-300.fc25.x86_64 #1 SMP Tue Nov 1 12:36:38 UTC 2016 x86_64 x86_64 x86_64 GNU/Linux
btrfs-progs v4.6.1
Comment 4 Lars 2017-01-14 12:11:51 UTC
dmesg from mount:

[142544.343499] BTRFS info (device sdd4): disk space caching is enabled
[142544.343503] BTRFS info (device sdd4): has skinny extents
[142544.426635] BTRFS info (device sdd4): bdev /dev/sdd4 errs: wr 91415, rd 156614, flush 1021, corrupt 0, gen 0
[142544.426648] BTRFS info (device sdd4): bdev /dev/sdc4 errs: wr 3241485, rd 41533, flush 72838, corrupt 40705, gen 0
[142544.847823] BTRFS error (device sdd4): bad fsid on block 336756948992
[142544.860800] BTRFS error (device sdd4): bad fsid on block 336756916224
[142544.860920] BTRFS error (device sdd4): bad fsid on block 336756899840
[142544.861417] BTRFS error (device sdd4): bad fsid on block 336756899840
[142544.861452] BTRFS error (device sdd4): failed to read block groups: -5
[142544.883330] BTRFS: open_ctree failed

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