loop6: detected capacity change from 0 to 64
============================================
WARNING: possible recursive locking detected
syzkaller #0 Not tainted
--------------------------------------------
syz.6.256/7663 is trying to acquire lock:
ffff88810b97e0b0 (&tree->tree_lock#2/1){+.+.}-{4:4}, at: hfs_find_init+0x18e/0x2c0

but task is already holding lock:
ffff88810b97e0b0 (&tree->tree_lock#2/1){+.+.}-{4:4}, at: hfs_find_init+0x18e/0x2c0

other info that might help us debug this:
 Possible unsafe locking scenario:

       CPU0
       ----
  lock(&tree->tree_lock#2/1);
  lock(&tree->tree_lock#2/1);

 *** DEADLOCK ***

 May be due to missing lock nesting notation

5 locks held by syz.6.256/7663:
 #0: ffff88810884a420 (sb_writers#26){.+.+}-{0:0}, at: vfs_write+0x211/0xb30
 #1: ffff888116e136a0 (&sb->s_type->i_mutex_key#31){+.+.}-{4:4}, at: generic_file_write_iter+0xeb/0x550
 #2: ffff888116e134f8 (&HFS_I(inode)->extents_lock){+.+.}-{4:4}, at: hfs_extend_file+0xda/0x14c0
 #3: ffff88810b97e0b0 (&tree->tree_lock#2/1){+.+.}-{4:4}, at: hfs_find_init+0x18e/0x2c0
 #4: ffff888116e12178 (&HFS_I(tree->inode)->extents_lock){+.+.}-{4:4}, at: hfs_extend_file+0xda/0x14c0

stack backtrace:
CPU: 0 UID: 0 PID: 7663 Comm: syz.6.256 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
Call Trace:
 <TASK>
 dump_stack_lvl+0x189/0x250
 print_deadlock_bug+0x28b/0x2a0
 validate_chain+0x1a3f/0x2140
 __lock_acquire+0xab9/0xd20
 lock_acquire+0x120/0x360
 __mutex_lock+0x187/0x1350
 hfs_find_init+0x18e/0x2c0
 hfs_extend_file+0x2f6/0x14c0
 hfs_bmap_reserve+0x107/0x430
 __hfs_ext_write_extent+0x1fa/0x470
 __hfs_ext_cache_extent+0x6b/0x9b0
 hfs_extend_file+0x31e/0x14c0
 hfs_get_block+0x3d7/0xbd0
 __block_write_begin_int+0x6b5/0x1900
 cont_write_begin+0x789/0xb50
 hfs_write_begin+0x66/0xb0
 cont_write_begin+0x2fd/0xb50
 hfs_write_begin+0x66/0xb0
 generic_perform_write+0x2c5/0x900
 generic_file_write_iter+0x117/0x550
 vfs_write+0x5c9/0xb30
 __x64_sys_pwrite64+0x193/0x220
 do_syscall_64+0xfa/0xfa0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7effb178f749
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007effb25a0038 EFLAGS: 00000246 ORIG_RAX: 0000000000000012
RAX: ffffffffffffffda RBX: 00007effb19e5fa0 RCX: 00007effb178f749
RDX: 000000000000ff10 RSI: 0000200000000140 RDI: 0000000000000005
RBP: 00007effb1813f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000008000c61 R11: 0000000000000246 R12: 0000000000000000
R13: 00007effb19e6038 R14: 00007effb19e5fa0 R15: 00007ffc04f0f3d8
 </TASK>
