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ab0db043c3
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Josef Bacik ab0db043c3 btrfs: fix lockdep splat from btrfs_dump_space_info 
When running with -o enospc_debug you can get the following splat if one
of the dump_space_info's trip

  ======================================================
  WARNING: possible circular locking dependency detected
  5.8.0-rc5+ #20 Tainted: G           OE
  ------------------------------------------------------
  dd/563090 is trying to acquire lock:
  ffff9e7dbf4f1e18 (&ctl->tree_lock){+.+.}-{2:2}, at: btrfs_dump_free_space+0x2b/0xa0 [btrfs]

  but task is already holding lock:
  ffff9e7e2284d428 (&cache->lock){+.+.}-{2:2}, at: btrfs_dump_space_info+0xaa/0x120 [btrfs]

  which lock already depends on the new lock.

  the existing dependency chain (in reverse order) is:

  -> #3 (&cache->lock){+.+.}-{2:2}:
	 _raw_spin_lock+0x25/0x30
	 btrfs_add_reserved_bytes+0x3c/0x3c0 [btrfs]
	 find_free_extent+0x7ef/0x13b0 [btrfs]
	 btrfs_reserve_extent+0x9b/0x180 [btrfs]
	 btrfs_alloc_tree_block+0xc1/0x340 [btrfs]
	 alloc_tree_block_no_bg_flush+0x4a/0x60 [btrfs]
	 __btrfs_cow_block+0x122/0x530 [btrfs]
	 btrfs_cow_block+0x106/0x210 [btrfs]
	 commit_cowonly_roots+0x55/0x300 [btrfs]
	 btrfs_commit_transaction+0x4ed/0xac0 [btrfs]
	 sync_filesystem+0x74/0x90
	 generic_shutdown_super+0x22/0x100
	 kill_anon_super+0x14/0x30
	 btrfs_kill_super+0x12/0x20 [btrfs]
	 deactivate_locked_super+0x36/0x70
	 cleanup_mnt+0x104/0x160
	 task_work_run+0x5f/0x90
	 __prepare_exit_to_usermode+0x1bd/0x1c0
	 do_syscall_64+0x5e/0xb0
	 entry_SYSCALL_64_after_hwframe+0x44/0xa9

  -> #2 (&space_info->lock){+.+.}-{2:2}:
	 _raw_spin_lock+0x25/0x30
	 btrfs_block_rsv_release+0x1a6/0x3f0 [btrfs]
	 btrfs_inode_rsv_release+0x4f/0x170 [btrfs]
	 btrfs_clear_delalloc_extent+0x155/0x480 [btrfs]
	 clear_state_bit+0x81/0x1a0 [btrfs]
	 __clear_extent_bit+0x25c/0x5d0 [btrfs]
	 clear_extent_bit+0x15/0x20 [btrfs]
	 btrfs_invalidatepage+0x2b7/0x3c0 [btrfs]
	 truncate_cleanup_page+0x47/0xe0
	 truncate_inode_pages_range+0x238/0x840
	 truncate_pagecache+0x44/0x60
	 btrfs_setattr+0x202/0x5e0 [btrfs]
	 notify_change+0x33b/0x490
	 do_truncate+0x76/0xd0
	 path_openat+0x687/0xa10
	 do_filp_open+0x91/0x100
	 do_sys_openat2+0x215/0x2d0
	 do_sys_open+0x44/0x80
	 do_syscall_64+0x52/0xb0
	 entry_SYSCALL_64_after_hwframe+0x44/0xa9

  -> #1 (&tree->lock#2){+.+.}-{2:2}:
	 _raw_spin_lock+0x25/0x30
	 find_first_extent_bit+0x32/0x150 [btrfs]
	 write_pinned_extent_entries.isra.0+0xc5/0x100 [btrfs]
	 __btrfs_write_out_cache+0x172/0x480 [btrfs]
	 btrfs_write_out_cache+0x7a/0xf0 [btrfs]
	 btrfs_write_dirty_block_groups+0x286/0x3b0 [btrfs]
	 commit_cowonly_roots+0x245/0x300 [btrfs]
	 btrfs_commit_transaction+0x4ed/0xac0 [btrfs]
	 close_ctree+0xf9/0x2f5 [btrfs]
	 generic_shutdown_super+0x6c/0x100
	 kill_anon_super+0x14/0x30
	 btrfs_kill_super+0x12/0x20 [btrfs]
	 deactivate_locked_super+0x36/0x70
	 cleanup_mnt+0x104/0x160
	 task_work_run+0x5f/0x90
	 __prepare_exit_to_usermode+0x1bd/0x1c0
	 do_syscall_64+0x5e/0xb0
	 entry_SYSCALL_64_after_hwframe+0x44/0xa9

  -> #0 (&ctl->tree_lock){+.+.}-{2:2}:
	 __lock_acquire+0x1240/0x2460
	 lock_acquire+0xab/0x360
	 _raw_spin_lock+0x25/0x30
	 btrfs_dump_free_space+0x2b/0xa0 [btrfs]
	 btrfs_dump_space_info+0xf4/0x120 [btrfs]
	 btrfs_reserve_extent+0x176/0x180 [btrfs]
	 __btrfs_prealloc_file_range+0x145/0x550 [btrfs]
	 cache_save_setup+0x28d/0x3b0 [btrfs]
	 btrfs_start_dirty_block_groups+0x1fc/0x4f0 [btrfs]
	 btrfs_commit_transaction+0xcc/0xac0 [btrfs]
	 btrfs_alloc_data_chunk_ondemand+0x162/0x4c0 [btrfs]
	 btrfs_check_data_free_space+0x4c/0xa0 [btrfs]
	 btrfs_buffered_write.isra.0+0x19b/0x740 [btrfs]
	 btrfs_file_write_iter+0x3cf/0x610 [btrfs]
	 new_sync_write+0x11e/0x1b0
	 vfs_write+0x1c9/0x200
	 ksys_write+0x68/0xe0
	 do_syscall_64+0x52/0xb0
	 entry_SYSCALL_64_after_hwframe+0x44/0xa9

  other info that might help us debug this:

  Chain exists of:
    &ctl->tree_lock --> &space_info->lock --> &cache->lock

   Possible unsafe locking scenario:

	 CPU0                    CPU1
	 ----                    ----
    lock(&cache->lock);
				 lock(&space_info->lock);
				 lock(&cache->lock);
    lock(&ctl->tree_lock);

   *** DEADLOCK ***

  6 locks held by dd/563090:
   #0: ffff9e7e21d18448 (sb_writers#14){.+.+}-{0:0}, at: vfs_write+0x195/0x200
   #1: ffff9e7dd0410ed8 (&sb->s_type->i_mutex_key#19){++++}-{3:3}, at: btrfs_file_write_iter+0x86/0x610 [btrfs]
   #2: ffff9e7e21d18638 (sb_internal#2){.+.+}-{0:0}, at: start_transaction+0x40b/0x5b0 [btrfs]
   #3: ffff9e7e1f05d688 (&cur_trans->cache_write_mutex){+.+.}-{3:3}, at: btrfs_start_dirty_block_groups+0x158/0x4f0 [btrfs]
   #4: ffff9e7e2284ddb8 (&space_info->groups_sem){++++}-{3:3}, at: btrfs_dump_space_info+0x69/0x120 [btrfs]
   #5: ffff9e7e2284d428 (&cache->lock){+.+.}-{2:2}, at: btrfs_dump_space_info+0xaa/0x120 [btrfs]

  stack backtrace:
  CPU: 3 PID: 563090 Comm: dd Tainted: G           OE     5.8.0-rc5+ #20
  Hardware name: To Be Filled By O.E.M. To Be Filled By O.E.M./890FX Deluxe5, BIOS P1.40 05/03/2011
  Call Trace:
   dump_stack+0x96/0xd0
   check_noncircular+0x162/0x180
   __lock_acquire+0x1240/0x2460
   ? wake_up_klogd.part.0+0x30/0x40
   lock_acquire+0xab/0x360
   ? btrfs_dump_free_space+0x2b/0xa0 [btrfs]
   _raw_spin_lock+0x25/0x30
   ? btrfs_dump_free_space+0x2b/0xa0 [btrfs]
   btrfs_dump_free_space+0x2b/0xa0 [btrfs]
   btrfs_dump_space_info+0xf4/0x120 [btrfs]
   btrfs_reserve_extent+0x176/0x180 [btrfs]
   __btrfs_prealloc_file_range+0x145/0x550 [btrfs]
   ? btrfs_qgroup_reserve_data+0x1d/0x60 [btrfs]
   cache_save_setup+0x28d/0x3b0 [btrfs]
   btrfs_start_dirty_block_groups+0x1fc/0x4f0 [btrfs]
   btrfs_commit_transaction+0xcc/0xac0 [btrfs]
   ? start_transaction+0xe0/0x5b0 [btrfs]
   btrfs_alloc_data_chunk_ondemand+0x162/0x4c0 [btrfs]
   btrfs_check_data_free_space+0x4c/0xa0 [btrfs]
   btrfs_buffered_write.isra.0+0x19b/0x740 [btrfs]
   ? ktime_get_coarse_real_ts64+0xa8/0xd0
   ? trace_hardirqs_on+0x1c/0xe0
   btrfs_file_write_iter+0x3cf/0x610 [btrfs]
   new_sync_write+0x11e/0x1b0
   vfs_write+0x1c9/0x200
   ksys_write+0x68/0xe0
   do_syscall_64+0x52/0xb0
   entry_SYSCALL_64_after_hwframe+0x44/0xa9

This is because we're holding the block_group->lock while trying to dump
the free space cache.  However we don't need this lock, we just need it
to read the values for the printk, so move the free space cache dumping
outside of the block group lock.

Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:47 +02:00
..
tests btrfs: make btrfs_set_extent_delalloc take btrfs_inode 2020-07-27 12:55:35 +02:00
acl.c btrfs: cleanup btrfs_setxattr_trans and drop transaction parameter 2019-04-29 19:02:44 +02:00
async-thread.c Btrfs: fix crash during unmount due to race with delayed inode workers 2020-03-23 17:01:51 +01:00
async-thread.h Btrfs: fix crash during unmount due to race with delayed inode workers 2020-03-23 17:01:51 +01:00
backref.c btrfs: fix double free on ulist after backref resolution failure 2020-07-21 21:59:15 +02:00
backref.h btrfs: rename BTRFS_ROOT_REF_COWS to BTRFS_ROOT_SHAREABLE 2020-05-25 11:25:35 +02:00
block-group.c btrfs: convert block group refcount to refcount_t 2020-07-27 12:55:42 +02:00
block-group.h btrfs: convert block group refcount to refcount_t 2020-07-27 12:55:42 +02:00
block-rsv.c btrfs: rename BTRFS_ROOT_REF_COWS to BTRFS_ROOT_SHAREABLE 2020-05-25 11:25:35 +02:00
block-rsv.h btrfs: Remove __ prefix from btrfs_block_rsv_release 2020-03-23 17:01:55 +01:00
btrfs_inode.h btrfs: reduce contention on log trees when logging checksums 2020-07-27 12:55:45 +02:00
check-integrity.c btrfs: check-integrity: remove unnecessary failure messages during memory allocation 2020-07-27 12:55:21 +02:00
check-integrity.h btrfs: remove btrfsic_submit_bh() 2020-03-23 17:01:39 +01:00
compression.c btrfs: remove fail label in check_compressed_csum 2020-07-27 12:55:42 +02:00
compression.h btrfs: make btrfs_submit_compressed_write take btrfs_inode 2020-07-27 12:55:31 +02:00
ctree.c btrfs: add little-endian optimized key helpers 2020-07-27 12:55:24 +02:00
ctree.h btrfs: don't WARN if we abort a transaction with EROFS 2020-07-27 12:55:46 +02:00
delalloc-space.c btrfs: make btrfs_delalloc_reserve_space take btrfs_inode 2020-07-27 12:55:36 +02:00
delalloc-space.h btrfs: make btrfs_delalloc_reserve_space take btrfs_inode 2020-07-27 12:55:36 +02:00
delayed-inode.c btrfs: use nofs allocations for running delayed items 2020-03-25 16:26:00 +01:00
delayed-inode.h btrfs: delayed-inode: Replace zero-length array with flexible-array member 2020-03-23 17:01:53 +01:00
delayed-ref.c btrfs: Remove __ prefix from btrfs_block_rsv_release 2020-03-23 17:01:55 +01:00
delayed-ref.h btrfs: migrate the delayed refs rsv code 2019-07-04 17:26:17 +02:00
dev-replace.c btrfs: sysfs, rename device_link add/remove functions 2020-03-23 17:01:35 +01:00
dev-replace.h btrfs: add __pure attribute to functions 2019-11-18 12:46:52 +01:00
dir-item.c btrfs: remove unused parameter fs_info from btrfs_extend_item 2019-04-29 19:02:50 +02:00
discard.c btrfs: discard: add missing put when grabbing block group from unused list 2020-07-07 16:06:28 +02:00
discard.h btrfs: discard: Use the correct style for SPDX License Identifier 2020-04-20 17:43:42 +02:00
disk-io.c btrfs: qgroup: remove ASYNC_COMMIT mechanism in favor of reserve retry-after-EDQUOT 2020-07-27 12:55:43 +02:00
disk-io.h btrfs: preallocate anon block device at first phase of snapshot creation 2020-07-27 12:55:38 +02:00
export.c btrfs: simplify iget helpers 2020-05-25 11:25:37 +02:00
export.h btrfs: export helpers for subvolume name/id resolution 2020-03-23 17:01:42 +01:00
extent_io.c btrfs: return EROFS for BTRFS_FS_STATE_ERROR cases 2020-07-27 12:55:46 +02:00
extent_io.h btrfs: don't use UAPI types for fiemap callback 2020-07-27 12:55:27 +02:00
extent_map.c Btrfs: fix race between using extent maps and merging them 2020-02-12 17:16:46 +01:00
extent_map.h btrfs: remove extent_map::bdev 2019-11-18 23:43:44 +01:00
extent-io-tree.h btrfs: streamline btrfs_get_io_failure_record logic 2020-07-27 12:55:39 +02:00
extent-tree.c btrfs: avoid possible signal interruption of btrfs_drop_snapshot() on relocation tree 2020-07-27 12:55:45 +02:00
file-item.c btrfs: make btrfs_csum_one_bio takae btrfs_inode 2020-07-27 12:55:26 +02:00
file.c btrfs: make btrfs_check_data_free_space take btrfs_inode 2020-07-27 12:55:36 +02:00
free-space-cache.c btrfs: make btrfs_dirty_pages take btrfs_inode 2020-07-27 12:55:35 +02:00
free-space-cache.h btrfs: let btrfs_return_cluster_to_free_space() return void 2020-07-27 12:55:21 +02:00
free-space-tree.c btrfs: move the root freeing stuff into btrfs_put_root 2020-03-23 17:01:59 +01:00
free-space-tree.h btrfs: rename btrfs_block_group_cache 2019-11-18 17:51:51 +01:00
inode-item.c btrfs: Make btrfs_find_name_in_ext_backref return struct btrfs_inode_extref 2019-09-09 14:59:16 +02:00
inode-map.c btrfs: make btrfs_delalloc_reserve_space take btrfs_inode 2020-07-27 12:55:36 +02:00
inode-map.h
inode.c btrfs: reduce contention on log trees when logging checksums 2020-07-27 12:55:45 +02:00
ioctl.c btrfs: add missing check for nocow and compression inode flags 2020-07-27 12:55:44 +02:00
Kconfig Revert "btrfs: switch to iomap_dio_rw() for dio" 2020-06-14 01:19:02 +02:00
locking.c btrfs: add missing annotation for btrfs_tree_lock() 2020-05-25 11:25:16 +02:00
locking.h btrfs: Implement DREW lock 2020-03-23 17:01:43 +01:00
lzo.c btrfs: compression: inline free_workspace 2019-11-18 12:46:59 +01:00
Makefile Btrfs: move all reflink implementation code into its own file 2020-03-23 17:01:54 +01:00
misc.h btrfs: rename tree_entry to rb_simple_node and export it 2020-05-25 11:25:19 +02:00
ordered-data.c btrfs: make btrfs_add_ordered_extent_dio take btrfs_inode 2020-07-27 12:55:34 +02:00
ordered-data.h btrfs: make btrfs_add_ordered_extent_dio take btrfs_inode 2020-07-27 12:55:34 +02:00
orphan.c
print-tree.c btrfs: Remove unneeded semicolon 2020-01-20 16:40:55 +01:00
print-tree.h
props.c btrfs: simplify iget helpers 2020-05-25 11:25:37 +02:00
props.h btrfs: delete unused function btrfs_set_prop_trans 2019-04-29 19:02:54 +02:00
qgroup.c btrfs: qgroup: remove ASYNC_COMMIT mechanism in favor of reserve retry-after-EDQUOT 2020-07-27 12:55:43 +02:00
qgroup.h btrfs: qgroup: export qgroups in sysfs 2020-07-27 12:55:37 +02:00
raid56.c btrfs: raid56: remove out label in __raid56_parity_recover 2020-07-27 12:55:44 +02:00
raid56.h btrfs: constify map parameter for nr_parity_stripes and nr_data_stripes 2019-07-01 13:34:58 +02:00
rcu-string.h btrfs: rcu-string: Replace zero-length array with flexible-array member 2020-03-23 17:01:53 +01:00
reada.c btrfs: rename btrfs_block_group_cache 2019-11-18 17:51:51 +01:00
ref-verify.c btrfs: ref-verify: fix memory leak in add_block_entry 2020-07-27 12:55:43 +02:00
ref-verify.h btrfs: ref-verify: Use btrfs_ref to refactor btrfs_ref_tree_mod() 2019-04-29 19:02:49 +02:00
reflink.c btrfs: reduce contention on log trees when logging checksums 2020-07-27 12:55:45 +02:00
reflink.h Btrfs: move all reflink implementation code into its own file 2020-03-23 17:01:54 +01:00
relocation.c btrfs: relocation: review the call sites which can be interrupted by signal 2020-07-27 12:55:45 +02:00
root-tree.c btrfs: simplify root lookup by id 2020-05-25 11:25:36 +02:00
scrub.c btrfs: return EROFS for BTRFS_FS_STATE_ERROR cases 2020-07-27 12:55:46 +02:00
send.c for-5.8-tag 2020-06-02 19:59:25 -07:00
send.h
space-info.c btrfs: fix lockdep splat from btrfs_dump_space_info 2020-07-27 12:55:47 +02:00
space-info.h btrfs: improve global reserve stealing logic 2020-05-25 11:25:22 +02:00
struct-funcs.c btrfs: update documentation of set/get helpers 2020-05-25 11:25:35 +02:00
super.c btrfs: document special case error codes for fs errors 2020-07-27 12:55:46 +02:00
sysfs.c btrfs: sysfs: use NOFS for device creation 2020-07-27 12:55:46 +02:00
sysfs.h btrfs: qgroup: export qgroups in sysfs 2020-07-27 12:55:37 +02:00
transaction.c btrfs: return EROFS for BTRFS_FS_STATE_ERROR cases 2020-07-27 12:55:46 +02:00
transaction.h btrfs: qgroup: remove ASYNC_COMMIT mechanism in favor of reserve retry-after-EDQUOT 2020-07-27 12:55:43 +02:00
tree-checker.c btrfs: tree-checker: remove duplicate definition of 'inode_item_err' 2020-05-25 11:25:23 +02:00
tree-checker.h btrfs: get fs_info from eb in btrfs_check_chunk_valid 2019-04-29 19:02:39 +02:00
tree-defrag.c btrfs: remove unused btrfs_root::defrag_trans_start 2020-07-27 12:55:28 +02:00
tree-log.c btrfs: reduce contention on log trees when logging checksums 2020-07-27 12:55:45 +02:00
tree-log.h btrfs: get fs_info from trans in btrfs_set_log_full_commit 2019-04-29 19:02:41 +02:00
ulist.c
ulist.h
uuid-tree.c btrfs: simplify root lookup by id 2020-05-25 11:25:36 +02:00
volumes.c btrfs: move the chunk_mutex in btrfs_read_chunk_tree 2020-07-27 12:55:46 +02:00
volumes.h btrfs: record btrfs_device directly in btrfs_io_bio 2020-07-27 12:55:40 +02:00
xattr.c Btrfs: fix failure to persist compression property xattr deletion on fsync 2019-06-17 16:37:17 +02:00
xattr.h btrfs: cleanup btrfs_setxattr_trans and drop transaction parameter 2019-04-29 19:02:44 +02:00
zlib.c btrfs: use larger zlib buffer for s390 hardware compression 2020-01-31 10:30:40 -08:00
zstd.c btrfs: compression: inline free_workspace 2019-11-18 12:46:59 +01:00