Re: [PATCH v6 4/6] fs: make vfs_fileattr_[get|set] return -EOPNOSUPP

Jiri Slaby
2025-10-06T11:09:11Z

On 30. 06. 25, 18:20, Andrey Albershteyn wrote:
> Future patches will add new syscalls which use these functions. As
> this interface won't be used for ioctls only, the EOPNOSUPP is more
> appropriate return code.
>
> This patch converts return code from ENOIOCTLCMD to EOPNOSUPP for
> vfs_fileattr_get and vfs_fileattr_set. To save old behavior translate
> EOPNOSUPP back for current users - overlayfs, encryptfs and fs/ioctl.c.
>
> Signed-off-by: Andrey Albershteyn <aalbersh@kernel.org>
...
> @@ -292,6 +294,8 @@ int ioctl_setflags(struct file *file, unsigned int __user *argp)
> fileattr_fill_flags(&fa, flags);
> err = vfs_fileattr_set(idmap, dentry, &fa);
> mnt_drop_write_file(file);
> + if (err == -EOPNOTSUPP)
> + err = -ENOIOCTLCMD;

This breaks borg code (unit tests already) as it expects EOPNOTSUPP, not
ENOIOCTLCMD/ENOTTY:
https://github.com/borgbackup/borg/blob/1c6ef7a200c7f72f8d1204d727fea32168616ceb/src/borg/platform/linux.pyx#L147

I.e. setflags now returns ENOIOCTLCMD/ENOTTY for cases where 6.16 used
to return EOPNOTSUPP.

This minimal testcase program doing ioctl(fd2, FS_IOC_SETFLAGS,
&FS_NODUMP_FL):
https://github.com/jirislaby/collected_sources/tree/master/ioctl_setflags

dumps in 6.16:
sf: ioctl: Operation not supported

with the above patch:
sf: ioctl: Inappropriate ioctl for device

Is this expected?

thanks,
--
js
suse labs