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d4b450cd4b33ce7c572e7fdccf33b59c4cdf361c
android_kernel_xiaomi_sm8450/fs/btrfs
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Filipe Manana d4b450cd4b Btrfs: fix race between transaction commit and empty block group removal 
Committing a transaction can race with automatic removal of empty block
groups (cleaner kthread), leading to a BUG_ON() in the transaction
commit code while running btrfs_finish_extent_commit(). The following
sequence diagram shows how it can happen:

           CPU 1                                       CPU 2

btrfs_commit_transaction()
  fs_info->running_transaction = NULL
  btrfs_finish_extent_commit()
    find_first_extent_bit()
      -> found range for block group X
         in fs_info->freed_extents[]

                                               btrfs_delete_unused_bgs()
                                                 -> found block group X

                                                 Removed block group X's range
                                                 from fs_info->freed_extents[]

                                                 btrfs_remove_chunk()
                                                    btrfs_remove_block_group(bg X)

    unpin_extent_range(bg X range)
       btrfs_lookup_block_group(bg X)
          -> returns NULL
            -> BUG_ON()

The trace that results from the BUG_ON() is:

[48665.187808] ------------[ cut here ]------------
[48665.188032] kernel BUG at fs/btrfs/extent-tree.c:5675!
[48665.188032] invalid opcode: 0000 [#1] SMP DEBUG_PAGEALLOC
[48665.188032] Modules linked in: dm_flakey dm_mod crc32c_generic btrfs xor raid6_pq nfsd auth_rpcgss oid_registry nfs_acl nfs lockd grace fscache sunrpc loop parport_pc evdev microcode
[48665.197388] CPU: 2 PID: 31211 Comm: kworker/u32:16 Tainted: G        W      3.19.0-rc5-btrfs-next-4+ #1
[48665.197388] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.7.5-0-ge51488c-20140602_164612-nilsson.home.kraxel.org 04/01/2014
[48665.197388] Workqueue: events_unbound btrfs_async_reclaim_metadata_space [btrfs]
[48665.197388] task: ffff880222011810 ti: ffff8801b56a4000 task.ti: ffff8801b56a4000
[48665.197388] RIP: 0010:[<ffffffffa0350d05>]  [<ffffffffa0350d05>] unpin_extent_range+0x6a/0x1ba [btrfs]
[48665.197388] RSP: 0018:ffff8801b56a7b88  EFLAGS: 00010246
[48665.197388] RAX: 0000000000000000 RBX: ffff8802143a6000 RCX: ffff8802220120c8
[48665.197388] RDX: 0000000000000001 RSI: 0000000000000001 RDI: ffff8800a3c140b0
[48665.197388] RBP: ffff8801b56a7bd8 R08: 0000000000000003 R09: 0000000000000000
[48665.197388] R10: 0000000000000000 R11: 000000000000bbac R12: 0000000012e8e000
[48665.197388] R13: ffff8800a3c14000 R14: 0000000000000000 R15: 0000000000000000
[48665.197388] FS:  0000000000000000(0000) GS:ffff88023ec40000(0000) knlGS:0000000000000000
[48665.197388] CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
[48665.197388] CR2: 00007f065e42f270 CR3: 0000000206f70000 CR4: 00000000000006e0
[48665.197388] Stack:
[48665.197388]  ffff8801b56a7bd8 0000000012ea0000 01ff8800a3c14138 0000000012e9ffff
[48665.197388]  ffff880141df3dd8 ffff8802143a6000 ffff8800a3c14138 ffff880141df3df0
[48665.197388]  ffff880141df3dd8 0000000000000000 ffff8801b56a7c08 ffffffffa0354227
[48665.197388] Call Trace:
[48665.197388]  [<ffffffffa0354227>] btrfs_finish_extent_commit+0xb0/0xd9 [btrfs]
[48665.197388]  [<ffffffffa0366b4b>] btrfs_commit_transaction+0x791/0x92c [btrfs]
[48665.197388]  [<ffffffffa0352432>] flush_space+0x43d/0x452 [btrfs]
[48665.197388]  [<ffffffff814295c3>] ? _raw_spin_unlock+0x28/0x33
[48665.197388]  [<ffffffffa035255f>] btrfs_async_reclaim_metadata_space+0x118/0x164 [btrfs]
[48665.197388]  [<ffffffff81059917>] ? process_one_work+0x14b/0x3ab
[48665.197388]  [<ffffffff810599ac>] process_one_work+0x1e0/0x3ab
[48665.197388]  [<ffffffff81079fa9>] ? trace_hardirqs_off+0xd/0xf
[48665.197388]  [<ffffffff8105a55b>] worker_thread+0x210/0x2d0
[48665.197388]  [<ffffffff8105a34b>] ? rescuer_thread+0x2c3/0x2c3
[48665.197388]  [<ffffffff8105e5c0>] kthread+0xef/0xf7
[48665.197388]  [<ffffffff81429682>] ? _raw_spin_unlock_irq+0x2d/0x39
[48665.197388]  [<ffffffff8105e4d1>] ? __kthread_parkme+0xad/0xad
[48665.197388]  [<ffffffff81429dec>] ret_from_fork+0x7c/0xb0
[48665.197388]  [<ffffffff8105e4d1>] ? __kthread_parkme+0xad/0xad
[48665.197388] Code: 85 f6 74 14 49 8b 06 49 03 46 09 49 39 c4 72 1d 4c 89 f7 e8 83 ec ff ff 4c 89 e6 4c 89 ef e8 1e f1 ff ff 48 85 c0 49 89 c6 75 02 <0f> 0b 49 8b 1e 49 03 5e 09 48 8b
[48665.197388] RIP  [<ffffffffa0350d05>] unpin_extent_range+0x6a/0x1ba [btrfs]
[48665.197388]  RSP <ffff8801b56a7b88>
[48665.272246] ---[ end trace b9c6ab9957521376 ]---

Fix this by ensuring that unpining the block group's range in
btrfs_finish_extent_commit() is done in a synchronized fashion
with removing the block group's range from freed_extents[]
in btrfs_delete_unused_bgs()

This race got introduced with the change:

    Btrfs: remove empty block groups automatically
    commit 47ab2a6c68

Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Chris Mason <clm@fb.com>
2015-02-02 19:24:48 -08:00
..
tests
btrfs: switch extent_state state to unsigned
2015-01-21 18:02:04 -08:00
acl.c
btrfs: remove useless ACL check
2014-06-09 17:20:42 -07:00
async-thread.c
btrfs: remove unlikely from NULL checks
2014-10-02 16:06:19 +02:00
async-thread.h
Btrfs: implement repair function when direct read fails
2014-09-17 13:39:01 -07:00
backref.c
btrfs: cleanup, remove inode_ref_info helper
2015-01-14 19:23:47 +01:00
backref.h
btrfs: cleanup, remove inode_item_info helper
2015-01-14 19:23:47 +01:00
btrfs_inode.h
Btrfs: Add code to support file creation time
2015-02-02 18:39:16 -08:00
check-integrity.c
Btrfs: include vmalloc.h in check-integrity.c
2014-11-25 06:01:11 -08:00
check-integrity.h
block: submit_bio_wait() conversions
2013-11-24 16:33:41 -07:00
compression.c
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs
2014-12-12 11:15:23 -08:00
compression.h
btrfs: zero out left over bytes after processing compression streams
2014-11-30 09:33:51 -08:00
ctree.c
Btrfs: insert_new_root: Fix lock type of the extent buffer.
2015-01-22 05:42:23 -08:00
ctree.h
Btrfs: fix race between transaction commit and empty block group removal
2015-02-02 19:24:48 -08:00
delayed-inode.c
Btrfs: Add code to support file creation time
2015-02-02 18:39:16 -08:00
delayed-inode.h
Btrfs: introduce the delayed inode ref deletion for the single link inode
2014-01-28 13:20:09 -08:00
delayed-ref.c
Btrfs: rework qgroup accounting
2014-06-09 17:20:48 -07:00
delayed-ref.h
Btrfs: rework qgroup accounting
2014-06-09 17:20:48 -07:00
dev-replace.c
Btrfs: btrfs_rm_dev_replace_blocked(): Use wait_event()
2015-01-21 18:06:48 -08:00
dev-replace.h
Btrfs: add new sources for device replace code
2012-12-12 17:15:41 -05:00
dir-item.c
Btrfs: make xattr replace operations atomic
2014-11-20 17:20:07 -08:00
disk-io.c
Btrfs: fix race between transaction commit and empty block group removal
2015-02-02 19:24:48 -08:00
disk-io.h
btrfs: sink blocksize parameter to btrfs_find_create_tree_block
2014-12-12 18:07:21 +01:00
export.c
btrfs: kill the key type accessor helpers
2014-09-17 13:37:12 -07:00
export.h
NFS support for btrfs - v3
2008-09-25 11:04:06 -04:00
extent_io.c
Btrfs: add ref_count and free function for btrfs_bio
2015-01-21 18:06:48 -08:00
extent_io.h
btrfs: switch extent_state state to unsigned
2015-01-21 18:02:04 -08:00
extent_map.c
Btrfs: do not move em to modified list when unpinning
2014-11-21 11:59:54 -08:00
extent_map.h
Btrfs: fix NULL pointer crash when running balance and scrub concurrently
2014-06-19 14:20:55 -07:00
extent-tree.c
Btrfs: fix race between transaction commit and empty block group removal
2015-02-02 19:24:48 -08:00
file-item.c
Btrfs: fix kfree on list_head in btrfs_lookup_csums_range error cleanup
2014-11-04 06:59:04 -08:00
file.c
Btrfs: fix snapshot inconsistency after a file write followed by truncate
2014-11-25 07:41:23 -08:00
free-space-cache.c
Btrfs: track dirty block groups on their own list
2015-01-21 17:36:52 -08:00
free-space-cache.h
Btrfs: fix race between writing free space cache and trimming
2014-12-02 18:35:09 -08:00
hash.c
btrfs: LLVMLinux: Remove VLAIS
2014-10-14 10:51:22 +02:00
hash.h
Btrfs: fix btrfs boot when compiled as built-in
2014-01-28 13:20:31 -08:00
inode-item.c
Btrfs: fix fsync log replay for inodes with a mix of regular refs and extrefs
2015-01-21 18:02:05 -08:00
inode-map.c
Btrfs: fix race between writing free space cache and trimming
2014-12-02 18:35:09 -08:00
inode-map.h
Btrfs: Support reading/writing on disk free ino cache
2011-04-25 16:46:11 +08:00
inode.c
Btrfs: Add code to support file creation time
2015-02-02 18:39:16 -08:00
ioctl.c
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs
2014-12-12 11:15:23 -08:00
Kconfig
Btrfs: fix btrfs boot when compiled as built-in
2014-01-28 13:20:31 -08:00
locking.c
btrfs: fix lockups from btrfs_clear_path_blocking
2014-11-19 10:34:35 -08:00
locking.h
btrfs: fix lockups from btrfs_clear_path_blocking
2014-11-19 10:34:35 -08:00
lzo.c
btrfs: zero out left over bytes after processing compression streams
2014-11-30 09:33:51 -08:00
Makefile
Btrfs: add sanity tests for new qgroup accounting code
2014-06-09 17:20:49 -07:00
math.h
Btrfs: cleanup duplicated division functions
2012-12-11 13:31:30 -05:00
ordered-data.c
Btrfs: collect only the necessary ordered extents on ranged fsync
2014-11-21 11:59:56 -08:00
ordered-data.h
Btrfs: collect only the necessary ordered extents on ranged fsync
2014-11-21 11:59:56 -08:00
orphan.c
btrfs: kill the key type accessor helpers
2014-09-17 13:37:12 -07:00
print-tree.c
btrfs: remove parameter blocksize from read_tree_block
2014-10-02 17:14:50 +02:00
print-tree.h
btrfs: make static code static & remove dead code
2013-05-06 15:55:23 -04:00
props.c
Btrfs: add support for inode properties
2014-01-28 13:20:24 -08:00
props.h
Btrfs: add support for inode properties
2014-01-28 13:20:24 -08:00
qgroup.c
btrfs: qgroup: move WARN_ON() to the correct location.
2015-01-21 18:22:37 -08:00
qgroup.h
btrfs: qgroup: account shared subtrees during snapshot delete
2014-08-15 07:43:14 -07:00
raid56.c
Btrfs: Include map_type in raid_bio
2015-01-21 18:06:49 -08:00
raid56.h
Btrfs: Make raid_map array be inlined in btrfs_bio structure
2015-01-21 18:06:47 -08:00
rcu-string.h
Btrfs: use rcu to protect device->name
2012-06-14 21:29:16 -04:00
reada.c
Btrfs: add ref_count and free function for btrfs_bio
2015-01-21 18:06:48 -08:00
relocation.c
btrfs: sink blocksize parameter to tree_block_processed
2014-12-12 18:07:22 +01:00
root-tree.c
Btrfs: use bitfield instead of integer data type for the some variants in btrfs_root
2014-06-09 17:20:40 -07:00
scrub.c
Rename all ref_count to refs in struct
2015-01-21 18:06:50 -08:00
send.c
btrfs: kill btrfs_inode_*time helpers
2015-02-02 18:39:07 -08:00
send.h
btrfs: make static code static & remove dead code
2013-05-06 15:55:23 -04:00
struct-funcs.c
Btrfs: rewrite BTRFS_SETGET_FUNCS
2012-07-23 16:28:06 -04:00
super.c
btrfs: remove a no-op unfreeze superbock callback
2015-01-21 18:02:04 -08:00
sysfs.c
btrfs: move commit out of sysfs when changing label
2014-11-12 16:53:15 +01:00
sysfs.h
btrfs: code optimize: BTRFS_ATTR_RW could set the mode
2014-09-17 13:37:59 -07:00
transaction.c
Btrfs: track dirty block groups on their own list
2015-01-21 17:36:52 -08:00
transaction.h
Btrfs: track dirty block groups on their own list
2015-01-21 17:36:52 -08:00
tree-defrag.c
Btrfs: use bitfield instead of integer data type for the some variants in btrfs_root
2014-06-09 17:20:40 -07:00
tree-log.c
btrfs: kill btrfs_inode_*time helpers
2015-02-02 18:39:07 -08:00
tree-log.h
Btrfs: fix data corruption after fast fsync and writeback error
2014-09-19 06:57:51 -07:00
ulist.c
Btrfs: do not export ulist functions
2014-01-29 07:06:27 -08:00
ulist.h
Btrfs: Fix memory corruption by ulist_add_merge() on 32bit arch
2014-08-15 07:43:19 -07:00
uuid-tree.c
Btrfs: make btrfs_search_forward return with nodes unlocked
2014-09-17 13:38:02 -07:00
volumes.c
btrfs: add more checks to btrfs_read_sys_array
2015-02-02 19:24:39 -08:00
volumes.h
Btrfs: Include map_type in raid_bio
2015-01-21 18:06:49 -08:00
xattr.c
Btrfs: make xattr replace operations atomic
2014-11-20 17:20:07 -08:00
xattr.h
btrfs: use generic posix ACL infrastructure
2014-01-25 23:58:18 -05:00
zlib.c
btrfs: zero out left over bytes after processing compression streams
2014-11-30 09:33:51 -08:00