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ca10845a56
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Josef Bacik ca10845a56 btrfs: sysfs: init devices outside of the chunk_mutex 
While running btrfs/061, btrfs/073, btrfs/078, or btrfs/178 we hit the
following lockdep splat:

  ======================================================
  WARNING: possible circular locking dependency detected
  5.9.0-rc3+ #4 Not tainted
  ------------------------------------------------------
  kswapd0/100 is trying to acquire lock:
  ffff96ecc22ef4a0 (&delayed_node->mutex){+.+.}-{3:3}, at: __btrfs_release_delayed_node.part.0+0x3f/0x330

  but task is already holding lock:
  ffffffff8dd74700 (fs_reclaim){+.+.}-{0:0}, at: __fs_reclaim_acquire+0x5/0x30

  which lock already depends on the new lock.

  the existing dependency chain (in reverse order) is:

  -> #3 (fs_reclaim){+.+.}-{0:0}:
	 fs_reclaim_acquire+0x65/0x80
	 slab_pre_alloc_hook.constprop.0+0x20/0x200
	 kmem_cache_alloc+0x37/0x270
	 alloc_inode+0x82/0xb0
	 iget_locked+0x10d/0x2c0
	 kernfs_get_inode+0x1b/0x130
	 kernfs_get_tree+0x136/0x240
	 sysfs_get_tree+0x16/0x40
	 vfs_get_tree+0x28/0xc0
	 path_mount+0x434/0xc00
	 __x64_sys_mount+0xe3/0x120
	 do_syscall_64+0x33/0x40
	 entry_SYSCALL_64_after_hwframe+0x44/0xa9

  -> #2 (kernfs_mutex){+.+.}-{3:3}:
	 __mutex_lock+0x7e/0x7e0
	 kernfs_add_one+0x23/0x150
	 kernfs_create_link+0x63/0xa0
	 sysfs_do_create_link_sd+0x5e/0xd0
	 btrfs_sysfs_add_devices_dir+0x81/0x130
	 btrfs_init_new_device+0x67f/0x1250
	 btrfs_ioctl+0x1ef/0x2e20
	 __x64_sys_ioctl+0x83/0xb0
	 do_syscall_64+0x33/0x40
	 entry_SYSCALL_64_after_hwframe+0x44/0xa9

  -> #1 (&fs_info->chunk_mutex){+.+.}-{3:3}:
	 __mutex_lock+0x7e/0x7e0
	 btrfs_chunk_alloc+0x125/0x3a0
	 find_free_extent+0xdf6/0x1210
	 btrfs_reserve_extent+0xb3/0x1b0
	 btrfs_alloc_tree_block+0xb0/0x310
	 alloc_tree_block_no_bg_flush+0x4a/0x60
	 __btrfs_cow_block+0x11a/0x530
	 btrfs_cow_block+0x104/0x220
	 btrfs_search_slot+0x52e/0x9d0
	 btrfs_insert_empty_items+0x64/0xb0
	 btrfs_insert_delayed_items+0x90/0x4f0
	 btrfs_commit_inode_delayed_items+0x93/0x140
	 btrfs_log_inode+0x5de/0x2020
	 btrfs_log_inode_parent+0x429/0xc90
	 btrfs_log_new_name+0x95/0x9b
	 btrfs_rename2+0xbb9/0x1800
	 vfs_rename+0x64f/0x9f0
	 do_renameat2+0x320/0x4e0
	 __x64_sys_rename+0x1f/0x30
	 do_syscall_64+0x33/0x40
	 entry_SYSCALL_64_after_hwframe+0x44/0xa9

  -> #0 (&delayed_node->mutex){+.+.}-{3:3}:
	 __lock_acquire+0x119c/0x1fc0
	 lock_acquire+0xa7/0x3d0
	 __mutex_lock+0x7e/0x7e0
	 __btrfs_release_delayed_node.part.0+0x3f/0x330
	 btrfs_evict_inode+0x24c/0x500
	 evict+0xcf/0x1f0
	 dispose_list+0x48/0x70
	 prune_icache_sb+0x44/0x50
	 super_cache_scan+0x161/0x1e0
	 do_shrink_slab+0x178/0x3c0
	 shrink_slab+0x17c/0x290
	 shrink_node+0x2b2/0x6d0
	 balance_pgdat+0x30a/0x670
	 kswapd+0x213/0x4c0
	 kthread+0x138/0x160
	 ret_from_fork+0x1f/0x30

  other info that might help us debug this:

  Chain exists of:
    &delayed_node->mutex --> kernfs_mutex --> fs_reclaim

   Possible unsafe locking scenario:

	 CPU0                    CPU1
	 ----                    ----
    lock(fs_reclaim);
				 lock(kernfs_mutex);
				 lock(fs_reclaim);
    lock(&delayed_node->mutex);

   *** DEADLOCK ***

  3 locks held by kswapd0/100:
   #0: ffffffff8dd74700 (fs_reclaim){+.+.}-{0:0}, at: __fs_reclaim_acquire+0x5/0x30
   #1: ffffffff8dd65c50 (shrinker_rwsem){++++}-{3:3}, at: shrink_slab+0x115/0x290
   #2: ffff96ed2ade30e0 (&type->s_umount_key#36){++++}-{3:3}, at: super_cache_scan+0x38/0x1e0

  stack backtrace:
  CPU: 0 PID: 100 Comm: kswapd0 Not tainted 5.9.0-rc3+ #4
  Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.13.0-2.fc32 04/01/2014
  Call Trace:
   dump_stack+0x8b/0xb8
   check_noncircular+0x12d/0x150
   __lock_acquire+0x119c/0x1fc0
   lock_acquire+0xa7/0x3d0
   ? __btrfs_release_delayed_node.part.0+0x3f/0x330
   __mutex_lock+0x7e/0x7e0
   ? __btrfs_release_delayed_node.part.0+0x3f/0x330
   ? __btrfs_release_delayed_node.part.0+0x3f/0x330
   ? lock_acquire+0xa7/0x3d0
   ? find_held_lock+0x2b/0x80
   __btrfs_release_delayed_node.part.0+0x3f/0x330
   btrfs_evict_inode+0x24c/0x500
   evict+0xcf/0x1f0
   dispose_list+0x48/0x70
   prune_icache_sb+0x44/0x50
   super_cache_scan+0x161/0x1e0
   do_shrink_slab+0x178/0x3c0
   shrink_slab+0x17c/0x290
   shrink_node+0x2b2/0x6d0
   balance_pgdat+0x30a/0x670
   kswapd+0x213/0x4c0
   ? _raw_spin_unlock_irqrestore+0x41/0x50
   ? add_wait_queue_exclusive+0x70/0x70
   ? balance_pgdat+0x670/0x670
   kthread+0x138/0x160
   ? kthread_create_worker_on_cpu+0x40/0x40
   ret_from_fork+0x1f/0x30

This happens because we are holding the chunk_mutex at the time of
adding in a new device.  However we only need to hold the
device_list_mutex, as we're going to iterate over the fs_devices
devices.  Move the sysfs init stuff outside of the chunk_mutex to get
rid of this lockdep splat.

CC: stable@vger.kernel.org # 4.4.x: f3cd2c5811: btrfs: sysfs, rename device_link add/remove functions
CC: stable@vger.kernel.org # 4.4.x
Reported-by: David Sterba <dsterba@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07 12:12:19 +02:00
..
tests btrfs: make btrfs_set_extent_delalloc take btrfs_inode 2020-07-27 12:55:35 +02:00
acl.c
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: remove unnecessarily shadowed variables 2020-10-07 12:06:55 +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: make read_block_group_item return void 2020-10-07 12:06:56 +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: convert btrfs_inode_sectorsize to take btrfs_inode 2020-10-07 12:12:18 +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: compression: move declarations to header 2020-10-07 12:06:55 +02:00
compression.h btrfs: compression: move declarations to header 2020-10-07 12:06:55 +02:00
ctree.c btrfs: use BTRFS_NESTED_NEW_ROOT for double splits 2020-10-07 12:12:17 +02:00
ctree.h btrfs: convert btrfs_inode_sectorsize to take btrfs_inode 2020-10-07 12:12:18 +02:00
delalloc-space.c btrfs: add btrfs_reserve_data_bytes and use it 2020-10-07 12:06:52 +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: qgroup: fix wrong qgroup metadata reserve for delayed inode 2020-10-07 12:12:13 +02:00
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
dev-replace.c btrfs: change nr to u64 in btrfs_start_delalloc_roots 2020-10-07 12:06:50 +02:00
dev-replace.h
dir-item.c
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: introduce BTRFS_NESTING_COW for cow'ing blocks 2020-10-07 12:12:16 +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: make extent_fiemap take btrfs_inode 2020-10-07 12:12:19 +02:00
extent_io.h btrfs: make extent_fiemap take btrfs_inode 2020-10-07 12:12:19 +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: add owner and fs_info to alloc_state io_tree 2020-10-07 12:06:56 +02:00
extent-tree.c btrfs: introduce BTRFS_NESTING_COW for cow'ing blocks 2020-10-07 12:12:16 +02:00
file-item.c btrfs: make btrfs_find_ordered_sum take btrfs_inode 2020-10-07 12:12:19 +02:00
file.c btrfs: make btrfs_zero_range_check_range_boundary take btrfs_inode 2020-10-07 12:12:19 +02:00
free-space-cache.c btrfs: delete duplicated words + other fixes in comments 2020-10-07 12:06:50 +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: block-group: fix free-space bitmap threshold 2020-08-27 13:37:54 +02:00
free-space-tree.h btrfs: rename btrfs_block_group_cache 2019-11-18 17:51:51 +01:00
inode-item.c
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: make extent_fiemap take btrfs_inode 2020-10-07 12:12:19 +02:00
ioctl.c btrfs: introduce BTRFS_NESTING_COW for cow'ing blocks 2020-10-07 12:12:16 +02:00
Kconfig btrfs: switch to iomap for direct IO 2020-10-07 12:06:57 +02:00
locking.c btrfs: add nesting tags to the locking helpers 2020-10-07 12:12:16 +02:00
locking.h btrfs: introduce BTRFS_NESTING_NEW_ROOT for adding new roots 2020-10-07 12:12:17 +02:00
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_find_ordered_sum take btrfs_inode 2020-10-07 12:12:19 +02:00
ordered-data.h btrfs: make btrfs_find_ordered_sum take btrfs_inode 2020-10-07 12:12:19 +02:00
orphan.c
print-tree.c btrfs: require only sector size alignment for parent eb bytenr 2020-09-07 14:51:05 +02:00
print-tree.h
props.c btrfs: simplify iget helpers 2020-05-25 11:25:37 +02:00
props.h
qgroup.c btrfs: delete duplicated words + other fixes in comments 2020-10-07 12:06:50 +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
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: switch seed device to list api 2020-10-07 12:06:58 +02:00
ref-verify.c btrfs: ref-verify: fix memory leak in add_block_entry 2020-07-27 12:55:43 +02:00
ref-verify.h
reflink.c btrfs: make copy_inline_to_page take btrfs_inode 2020-10-07 12:12:19 +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: introduce BTRFS_NESTING_COW for cow'ing blocks 2020-10-07 12:12:16 +02:00
root-tree.c btrfs: qgroup: fix qgroup meta rsv leak for subvolume operations 2020-10-07 12:12:13 +02:00
scrub.c btrfs: scrub: rename ratelimit state varaible to avoid shadowing 2020-10-07 12:06:55 +02:00
send.c btrfs: send: remove indirect callback parameter for changed_cb 2020-10-07 12:06:55 +02:00
send.h
space-info.c btrfs: fix possible infinite loop in data async reclaim 2020-10-07 12:06:54 +02:00
space-info.h btrfs: add btrfs_reserve_data_bytes and use it 2020-10-07 12:06:52 +02:00
struct-funcs.c btrfs: update documentation of set/get helpers 2020-05-25 11:25:35 +02:00
super.c btrfs: do async reclaim for data reservations 2020-10-07 12:06:54 +02:00
sysfs.c btrfs: simplify setting/clearing fs_info to btrfs_fs_devices 2020-10-07 12:06:58 +02:00
sysfs.h btrfs: remove const from btrfs_feature_set_name 2020-10-07 12:06:55 +02:00
transaction.c btrfs: introduce BTRFS_NESTING_COW for cow'ing blocks 2020-10-07 12:12:16 +02:00
transaction.h btrfs: dio iomap DSYNC workaround 2020-10-07 12:06:57 +02:00
tree-checker.c btrfs: tree-checker: fix the error message for transid error 2020-08-27 14:16:05 +02:00
tree-checker.h
tree-defrag.c btrfs: remove unused btrfs_root::defrag_trans_start 2020-07-27 12:55:28 +02:00
tree-log.c btrfs: make fast fsyncs wait only for writeback 2020-10-07 12:06:56 +02:00
tree-log.h btrfs: make fast fsyncs wait only for writeback 2020-10-07 12:06:56 +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: sysfs: init devices outside of the chunk_mutex 2020-10-07 12:12:19 +02:00
volumes.h btrfs: switch seed device to list api 2020-10-07 12:06:58 +02:00
xattr.c
xattr.h
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