EXT4-fs (loop0): Delayed block allocation failed for inode 18 at logical offset 0 with max blocks 2048 with error 28
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sb_rdonly(sb)
WARNING: fs/ext4/ext4_jbd2.c:75 at ext4_journal_check_start+0x24f/0x2b0 fs/ext4/ext4_jbd2.c:75, CPU#0: kworker/u4:11/4046
Modules linked in:
CPU: 0 UID: 0 PID: 4046 Comm: kworker/u4:11 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
Workqueue: writeback wb_workfn (flush-7:0)
RIP: 0010:ext4_journal_check_start+0x24f/0x2b0 fs/ext4/ext4_jbd2.c:75
Code: 5b 41 5c 41 5d 41 5e 41 5f 5d c3 cc cc cc cc cc e8 56 e8 44 ff 41 bf fb ff ff ff eb e0 e8 49 e8 44 ff eb d3 e8 42 e8 44 ff 90 <0f> 0b 90 eb c8 e8 37 e8 44 ff 90 0f 0b 90 43 80 7c 25 00 00 0f 85
RSP: 0018:ffffc900038a6c30 EFLAGS: 00010293
RAX: ffffffff8280b2de RBX: ffff88801fa6c000 RCX: ffff888043a30000
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: 0000000000000b5c R08: ffff888035e8a387 R09: 1ffff11006bd1470
R10: dffffc0000000000 R11: ffffed1006bd1471 R12: dffffc0000000000
R13: 1ffff11003f4d8c7 R14: ffff88801fa6c638 R15: 0000000000000001
FS:  0000000000000000(0000) GS:ffff88808ca5b000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f55d46064f0 CR3: 000000000e54c000 CR4: 0000000000352ef0
Call Trace:
 <TASK>
 __ext4_journal_start_sb+0x147/0x620 fs/ext4/ext4_jbd2.c:107
 __ext4_journal_start fs/ext4/ext4_jbd2.h:242 [inline]
 ext4_do_writepages+0xf94/0x46e0 fs/ext4/inode.c:2907
 ext4_writepages+0x241/0x3b0 fs/ext4/inode.c:3019
 do_writepages+0x32e/0x550 mm/page-writeback.c:2554
 __writeback_single_inode+0x133/0x11a0 fs/fs-writeback.c:1749
 writeback_sb_inodes+0x944/0x19a0 fs/fs-writeback.c:2040
 __writeback_inodes_wb+0x111/0x240 fs/fs-writeback.c:2117
 wb_writeback+0x46a/0xb70 fs/fs-writeback.c:2228
 wb_check_background_flush fs/fs-writeback.c:2298 [inline]
 wb_do_writeback fs/fs-writeback.c:2386 [inline]
 wb_workfn+0xbf9/0xf50 fs/fs-writeback.c:2413
 process_one_work kernel/workqueue.c:3275 [inline]
 process_scheduled_works+0xb02/0x1830 kernel/workqueue.c:3358
 worker_thread+0xa50/0xfc0 kernel/workqueue.c:3439
 kthread+0x388/0x470 kernel/kthread.c:467
 ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>