============================================
WARNING: possible recursive locking detected
syzkaller #0 Not tainted
--------------------------------------------
syz.0.0/5320 is trying to acquire lock:
ffff8880442a5da0 (&ocfs2_sysfile_lock_key[GLOBAL_BITMAP_SYSTEM_INODE]){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:1024 [inline]
ffff8880442a5da0 (&ocfs2_sysfile_lock_key[GLOBAL_BITMAP_SYSTEM_INODE]){+.+.}-{4:4}, at: ocfs2_reserve_suballoc_bits+0x170/0x4850 fs/ocfs2/suballoc.c:904

but task is already holding lock:
ffff8880442a5da0 (&ocfs2_sysfile_lock_key[GLOBAL_BITMAP_SYSTEM_INODE]){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:1024 [inline]
ffff8880442a5da0 (&ocfs2_sysfile_lock_key[GLOBAL_BITMAP_SYSTEM_INODE]){+.+.}-{4:4}, at: ocfs2_reserve_suballoc_bits+0x170/0x4850 fs/ocfs2/suballoc.c:904

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

       CPU0
       ----
  lock(&ocfs2_sysfile_lock_key[GLOBAL_BITMAP_SYSTEM_INODE]);
  lock(&ocfs2_sysfile_lock_key[GLOBAL_BITMAP_SYSTEM_INODE]);

 *** DEADLOCK ***

 May be due to missing lock nesting notation

locks held by syz.0.0/5320: 4, last CPU#0:
 #0: ffff888012fb8460 (sb_writers#11){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:494
 #1: ffff8880442aa5a0 (&type->i_mutex_dir_key#8){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:1024 [inline]
 #1: ffff8880442aa5a0 (&type->i_mutex_dir_key#8){+.+.}-{4:4}, at: lookup_open+0x242/0x1a40 fs/namei.c:4458
 #2: ffff8880442a41a0 (&ocfs2_sysfile_lock_key[INODE_ALLOC_SYSTEM_INODE]){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:1024 [inline]
 #2: ffff8880442a41a0 (&ocfs2_sysfile_lock_key[INODE_ALLOC_SYSTEM_INODE]){+.+.}-{4:4}, at: ocfs2_reserve_suballoc_bits+0x170/0x4850 fs/ocfs2/suballoc.c:904
 #3: ffff8880442a5da0 (&ocfs2_sysfile_lock_key[GLOBAL_BITMAP_SYSTEM_INODE]){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:1024 [inline]
 #3: ffff8880442a5da0 (&ocfs2_sysfile_lock_key[GLOBAL_BITMAP_SYSTEM_INODE]){+.+.}-{4:4}, at: ocfs2_reserve_suballoc_bits+0x170/0x4850 fs/ocfs2/suballoc.c:904

stack backtrace:
CPU: 0 UID: 0 PID: 5320 Comm: syz.0.0 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 print_deadlock_bug+0x27a/0x290 kernel/locking/lockdep.c:3057
 check_deadlock kernel/locking/lockdep.c:3109 [inline]
 validate_chain kernel/locking/lockdep.c:3911 [inline]
 __lock_acquire+0x261c/0x2e50 kernel/locking/lockdep.c:5254
 lock_acquire+0x115/0x350 kernel/locking/lockdep.c:5908
 down_write+0x96/0x200 kernel/locking/rwsem.c:1631
 inode_lock include/linux/fs.h:1024 [inline]
 ocfs2_reserve_suballoc_bits+0x170/0x4850 fs/ocfs2/suballoc.c:904
 ocfs2_reserve_cluster_bitmap_bits fs/ocfs2/suballoc.c:1250 [inline]
 ocfs2_reserve_clusters_with_limit+0x3bc/0xc20 fs/ocfs2/suballoc.c:1295
 ocfs2_mknod+0xf10/0x22b0 fs/ocfs2/namei.c:363
 ocfs2_create+0x195/0x460 fs/ocfs2/namei.c:683
 lookup_open+0xc0d/0x1a40 fs/namei.c:4567
 open_last_lookups fs/namei.c:4767 [inline]
 path_openat+0x677/0x1d60 fs/namei.c:4997
 do_file_open+0x23e/0x4a0 fs/namei.c:5029
 do_sys_openat2+0x115/0x200 fs/open.c:1417
 do_sys_open fs/open.c:1423 [inline]
 __do_sys_creat fs/open.c:1501 [inline]
 __se_sys_creat fs/open.c:1495 [inline]
 __x64_sys_creat+0x8f/0xc0 fs/open.c:1495
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f913119e159
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f91320d1fe8 EFLAGS: 00000246 ORIG_RAX: 0000000000000055
RAX: ffffffffffffffda RBX: 00007f9131426090 RCX: 00007f913119e159
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000200000000380
RBP: 00007f9131235024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f9131426128 R14: 00007f9131426090 R15: 00007ffd8de963d8
 </TASK>