syzbot

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BUG: KCSAN: data-race in ext4_da_reserve_space / ext4_file_getattr

write to 0xffff8880b6e1d638 of 4 bytes by task 30613 on cpu 1:
 ext4_da_reserve_space+0x12b/0x220 fs/ext4/inode.c:1476
 ext4_insert_delayed_block fs/ext4/inode.c:1641 [inline]
 ext4_da_map_blocks fs/ext4/inode.c:1755 [inline]
 ext4_da_get_block_prep+0x4d5/0x990 fs/ext4/inode.c:1819
 ext4_block_write_begin+0x433/0xb60 fs/ext4/inode.c:1061
 ext4_da_write_begin+0x4e8/0xa30 fs/ext4/inode.c:2997
 generic_perform_write+0x196/0x390 mm/filemap.c:3318
 ext4_buffered_write_iter+0x2cc/0x3b0 fs/ext4/file.c:270
 ext4_file_write_iter+0x76f/0x1010 include/linux/fs.h:805
 call_write_iter include/linux/fs.h:1908 [inline]
 do_iter_readv_writev+0x321/0x3c0 fs/read_write.c:713
 do_iter_write+0x10e/0x470 fs/read_write.c:1018
 vfs_writev fs/read_write.c:1091 [inline]
 do_pwritev+0x1a4/0x2e0 fs/read_write.c:1188
 __do_sys_pwritev2 fs/read_write.c:1247 [inline]
 __se_sys_pwritev2 fs/read_write.c:1238 [inline]
 __x64_sys_pwritev2+0x7e/0xa0 fs/read_write.c:1238
 do_syscall_64+0x51/0xb0 arch/x86/entry/common.c:384
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff8880b6e1d638 of 4 bytes by task 30625 on cpu 0:
 ext4_file_getattr+0xac/0x170 fs/ext4/inode.c:5506
 vfs_getattr_nosec+0x178/0x310 fs/stat.c:87
 vfs_getattr fs/stat.c:124 [inline]
 vfs_statx+0x148/0x2b0 fs/stat.c:206
 vfs_fstatat include/linux/fs.h:3308 [inline]
 __do_sys_newfstatat fs/stat.c:388 [inline]
 __se_sys_newfstatat+0x4c/0x250 fs/stat.c:382
 __x64_sys_newfstatat+0x51/0x60 fs/stat.c:382
 do_syscall_64+0x51/0xb0 arch/x86/entry/common.c:384
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 30625 Comm: syz-executor.2 Not tainted 5.8.0-rc7-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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