------------[ cut here ]------------
whichfork != XFS_COW_FORK
WARNING: fs/xfs/libxfs/xfs_bmap.c:4397 at xfs_bmapi_convert_one_delalloc fs/xfs/libxfs/xfs_bmap.c:4397 [inline], CPU#0: syz.0.0/5359
WARNING: fs/xfs/libxfs/xfs_bmap.c:4397 at xfs_bmapi_convert_delalloc+0x117d/0x1550 fs/xfs/libxfs/xfs_bmap.c:4503, CPU#0: syz.0.0/5359
Modules linked in:
CPU: 0 UID: 0 PID: 5359 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
RIP: 0010:xfs_bmapi_convert_one_delalloc fs/xfs/libxfs/xfs_bmap.c:4397 [inline]
RIP: 0010:xfs_bmapi_convert_delalloc+0x117d/0x1550 fs/xfs/libxfs/xfs_bmap.c:4503
Code: df 31 f6 e8 b5 50 01 00 eb 05 e8 4e c1 32 fe 48 8b bc 24 e0 01 00 00 e8 41 f4 1e 00 41 89 c4 e9 e0 f2 ff ff e8 34 c1 32 fe 90 <0f> 0b 90 e9 bd f2 ff ff 44 89 e1 80 e1 07 38 c1 0f 8c 0c f1 ff ff
RSP: 0018:ffffc9000e63ef20 EFLAGS: 00010287
RAX: ffffffff83965f6c RBX: 1ffff92001cc7dfc RCX: 0000000000100000
RDX: ffffc90020001000 RSI: 0000000000000464 RDI: 0000000000000465
RBP: ffffc9000e63f170 R08: ffffc9000e63f050 R09: 0000000000000002
R10: 0000000000000001 R11: 0000000000000002 R12: 0000000000000002
R13: 0000000000000000 R14: dffffc0000000000 R15: 1ffff92001cc7dfc
FS:  00007f69201326c0(0000) GS:ffff88808a9fe000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f6920111000 CR3: 000000000c0ee000 CR4: 0000000000352ef0
Call Trace:
 <TASK>
 xfs_buffered_write_iomap_begin+0xd50/0x2350 fs/xfs/xfs_iomap.c:2105
 iomap_iter_next include/linux/iomap.h:382 [inline]
 xfs_buffered_write_iomap_next+0x52c/0x740 fs/xfs/xfs_iomap.c:2194
 iomap_iter+0xe2/0xec0 fs/iomap/iter.c:123
 iomap_zero_range+0xb85/0xca0 fs/iomap/buffered-io.c:1771
 xfs_zero_range+0x9a/0x100 fs/xfs/xfs_iomap.c:2402
 xfs_file_write_zero_eof fs/xfs/xfs_file.c:430 [inline]
 xfs_file_write_checks+0x5f0/0xa80 fs/xfs/xfs_file.c:497
 xfs_file_buffered_write+0x19f/0x870 fs/xfs/xfs_file.c:1038
 aio_write+0x5cb/0x870 fs/aio.c:1697
 __io_submit_one fs/aio.c:-1 [inline]
 io_submit_one+0x798/0x13d0 fs/aio.c:2121
 __do_sys_io_submit fs/aio.c:2180 [inline]
 __se_sys_io_submit+0x195/0x340 fs/aio.c:2150
 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: 0033:0x7f691f19fb19
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:00007f6920131fe8 EFLAGS: 00000246 ORIG_RAX: 00000000000000d1
RAX: ffffffffffffffda RBX: 00007f691f426090 RCX: 00007f691f19fb19
RDX: 0000200000012100 RSI: 0000000000000008 RDI: 00007f6920111000
RBP: 00007f691f237b70 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f691f426128 R14: 00007f691f426090 R15: 00007ffe2e421a98
 </TASK>