On Sat, 21 Jan 2023 05:57:35 +0000
Yano Ray wrote:
> Hi,
> I tried to format a partition using mkfs.ext4 (e2fsprogs) but it failed with
> an error.
>
> $ /usr/sbin/mkfs.ext4 /dev/sde1
> mke2fs 1.44.5 (15-Dec-2018)
> Creating filesystem with 16384 1k blocks and 4096 inodes
> Filesystem UUID: fb09cfbf-9f2a-4874-82f7-26c7cb853093
> Superblock backups stored on blocks:
> 8193
>
> Allocating group tables: done
> Writing inode tables: done
> Creating journal (1024 blocks): done
> Writing superblocks and filesystem accounting information: mkfs.ext4: Invalid
> argument while writing out and closing file system
> $
>
> This also seems to happen with mkfs.minix (linux-utils).
>
> $ /sbin/mkfs.minix /dev/sde1
> 5472 inodes
> 16384 blocks
> Firstdatazone=176 (176)
> Zonesize=1024
> Maxsize=268966912
>
> mkfs.minix: write failed: Invalid argument
> $
>
> I think it's because fsync is not implemented (causes InvalidArgument) for
> block devices.
> Why fsync is not implemented for block devices?
>
> /* test code */
> #include <unistd.h>
> #include <fcntl.h>
> #include <errno.h>
> #include <stdio.h>
> #include <string.h>
>
> int main(int argc, char** argv) {
> int fd;
>
> if (argc != 2) {
> puts("./program [file]");
> return -1;
> }
>
> fd = open(argv[1], O_RDWR);
> printf("open: %s\n", strerror(errno));
> if (errno) return -1;
>
> fsync(fd);
> printf("fsync: %s\n", strerror(errno));
> if (errno) return -1;
> }
>
> on Cygwin:
> $ ./a.exe /dev/sde
> open: No error
> fsync: Invalid argument
> $ ./a.exe /dev/sde1
> open: No error
> fsync: Invalid argument
> $ uname -a
> CYGWIN_NT-10.0-22621 DESKTOP-5H6F7L3 3.4.5-1.x86_64 2023-01-19 19:09 UTC
> x86_64 Cygwin
> $
>
> expected behaviour (on Arch Linux):
> $ sudo ./a.out /dev/sda
> $ sudo ./a.out /dev/sda
> open: Success
> fsync: Success
> $ sudo ./a.out /dev/sda1
> open: Success
> fsync: Success
> $ uname -a
> Linux arch 6.0.11-arch1-1 #1 SMP PREEMPT_DYNAMIC Fri, 02 Dec 2022 17:25:31
> +0000 x86_64 GNU/Linux
> $
Thanks for the report. I looked into this problem and found
this causes after the commit:
commit af8a7c13b516c77c1e6092157e23ca26db44b1af
Author: Takashi Yano <takashi.y...@nifty.ne.jp>
Date: Sat Mar 12 06:19:53 2022 +0900
Cygwin: fsync: Return EINVAL for special files.
- Unlike linux, fsync() calls FlushFileBuffers() even for special
files. This causes the problem reported in:
https://cygwin.com/pipermail/cygwin/2022-March/251022.html
This patch fixes the issue.
I will submit a patch for this issue.
--
Takashi Yano <takashi.y...@nifty.ne.jp>
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