ntfs3: Cannot use different iocharset when remounting!
======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
syz.5.197/7035 is trying to acquire lock:
ffff88811f9fc9d0 (&ni->ni_lock#2/5){+.+.}-{4:4}, at: ntfs_fallocate+0x8e6/0x10b0

but task is already holding lock:
ffff88811f9fce08 (mapping.invalidate_lock#7){++++}-{4:4}, at: ntfs_fallocate+0x3b8/0x10b0

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #2 (mapping.invalidate_lock#7){++++}-{4:4}:
       down_read+0x47/0x2e0
       filemap_fault+0x5c3/0x1290
       __do_fault+0x138/0x390
       do_pte_missing+0x2206/0x3330
       handle_mm_fault+0x1b26/0x32b0
       do_user_addr_fault+0x764/0x1380
       exc_page_fault+0x71/0xd0
       asm_exc_page_fault+0x26/0x30
       rep_movs_alternative+0x75/0x90
       _copy_from_user+0x7a/0xb0
       __se_sys_mount+0x18b/0x410
       do_syscall_64+0xec/0xf80
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #1 (&mm->mmap_lock){++++}-{4:4}:
       __might_fault+0xcc/0x130
       _copy_to_user+0x2c/0xb0
       fiemap_fill_next_extent+0x1c0/0x390
       ni_fiemap+0x7e5/0xbf0
       ntfs_fiemap+0x11d/0x1a0
       do_vfs_ioctl+0x1173/0x1430
       __se_sys_ioctl+0x82/0x170
       do_syscall_64+0xec/0xf80
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #0 (&ni->ni_lock#2/5){+.+.}-{4:4}:
       __lock_acquire+0x15a6/0x2cf0
       lock_acquire+0x107/0x340
       __mutex_lock+0x187/0x1350
       ntfs_fallocate+0x8e6/0x10b0
       vfs_fallocate+0x669/0x7e0
       __x64_sys_fallocate+0xc0/0x110
       do_syscall_64+0xec/0xf80
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

other info that might help us debug this:

Chain exists of:
  &ni->ni_lock#2/5 --> &mm->mmap_lock --> mapping.invalidate_lock#7

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(mapping.invalidate_lock#7);
                               lock(&mm->mmap_lock);
                               lock(mapping.invalidate_lock#7);
  lock(&ni->ni_lock#2/5);

 *** DEADLOCK ***

3 locks held by syz.5.197/7035:
 #0: ffff8881ba498420 (sb_writers#17){++++}-{0:0}, at: vfs_fallocate+0x5f0/0x7e0
 #1: ffff88811f9fcc68 (&sb->s_type->i_mutex_key#31){+.+.}-{4:4}, at: ntfs_fallocate+0x2ee/0x10b0
 #2: ffff88811f9fce08 (mapping.invalidate_lock#7){++++}-{4:4}, at: ntfs_fallocate+0x3b8/0x10b0

stack backtrace:
CPU: 0 UID: 0 PID: 7035 Comm: syz.5.197 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+0xe8/0x150
 print_circular_bug+0x2e2/0x300
 check_noncircular+0x12e/0x150
 __lock_acquire+0x15a6/0x2cf0
 lock_acquire+0x107/0x340
 __mutex_lock+0x187/0x1350
 ntfs_fallocate+0x8e6/0x10b0
 vfs_fallocate+0x669/0x7e0
 __x64_sys_fallocate+0xc0/0x110
 do_syscall_64+0xec/0xf80
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f76e5d8f7c9
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:00007f76e6d07038 EFLAGS: 00000246 ORIG_RAX: 000000000000011d
RAX: ffffffffffffffda RBX: 00007f76e5fe5fa0 RCX: 00007f76e5d8f7c9
RDX: 0000000000004000 RSI: 0000000000000020 RDI: 0000000000000004
RBP: 00007f76e5df297f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000003000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f76e5fe6038 R14: 00007f76e5fe5fa0 R15: 00007ffda0616ca8
 </TASK>
