[PATCH 0/2] Fix to EOPNOTSUPP double conversion in ioctl_setflags()

[PATCH 0/2] Fix to EOPNOTSUPP double conversion in ioctl_setflags()

[Andrey Albershteyn]

Revert original double conversion patch from ENOIOCTLCMD to EOPNOSUPP for
vfs_fileattr_get and vfs_fileattr_set. Instead, convert ENOIOCTLCMD only
where necessary.

To: linux-api@vger.kernel.org
To: linux-fsdevel@vger.kernel.org
To: linux-kernel@vger.kernel.org
To: linux-xfs@vger.kernel.org,
Cc: "Jan Kara" <jack@suse.cz>
Cc: "Jiri Slaby" <jirislaby@kernel.org>
Cc: "Christian Brauner" <brauner@kernel.org>
Cc: "Arnd Bergmann" <arnd@arndb.de>

Signed-off-by: Andrey Albershteyn <aalbersh@kernel.org>
---
Andrey Albershteyn (2):
      Revert "fs: make vfs_fileattr_[get|set] return -EOPNOTSUPP"
      fs: return EOPNOTSUPP from file_setattr/file_getattr syscalls

 fs/file_attr.c         | 16 ++++++----------
 fs/fuse/ioctl.c        |  4 ----
 fs/overlayfs/copy_up.c |  2 +-
 fs/overlayfs/inode.c   |  5 ++++-
 4 files changed, 11 insertions(+), 16 deletions(-)
---
base-commit: e5f0a698b34ed76002dc5cff3804a61c80233a7a
change-id: 20251007-eopnosupp-fix-d2f30fd7d873

Best regards,
--  
Andrey Albershteyn <aalbersh@kernel.org>

[PATCH 1/2] Revert "fs: make vfs_fileattr_[get|set] return -EOPNOTSUPP"

[Andrey Albershteyn]

This reverts commit 474b155adf3927d2c944423045757b54aa1ca4de.

This patch caused regression in ioctl_setflags(). Underlying filesystems
use EOPNOTSUPP to indicate that flag is not supported. This error is
also gets converted in ioctl_setflags(). Therefore, for unsupported
flags error changed from EOPNOSUPP to ENOIOCTLCMD.

Link: https://lore.kernel.org/linux-xfs/a622643f-1585-40b0-9441-cf7ece176e83@kernel.org/
Signed-off-by: Andrey Albershteyn <aalbersh@kernel.org>
---
 fs/file_attr.c         | 12 ++----------
 fs/fuse/ioctl.c        |  4 ----
 fs/overlayfs/copy_up.c |  2 +-
 fs/overlayfs/inode.c   |  5 ++++-
 4 files changed, 7 insertions(+), 16 deletions(-)

diff --git a/fs/file_attr.c b/fs/file_attr.c
index 12424d4945d0..460b2dd21a85 100644
--- a/fs/file_attr.c
+++ b/fs/file_attr.c
@@ -84,7 +84,7 @@ int vfs_fileattr_get(struct dentry *dentry, struct file_kattr *fa)
 	int error;
 
 	if (!inode->i_op->fileattr_get)
-		return -EOPNOTSUPP;
+		return -ENOIOCTLCMD;
 
 	error = security_inode_file_getattr(dentry, fa);
 	if (error)
@@ -270,7 +270,7 @@ int vfs_fileattr_set(struct mnt_idmap *idmap, struct dentry *dentry,
 	int err;
 
 	if (!inode->i_op->fileattr_set)
-		return -EOPNOTSUPP;
+		return -ENOIOCTLCMD;
 
 	if (!inode_owner_or_capable(idmap, inode))
 		return -EPERM;
@@ -312,8 +312,6 @@ int ioctl_getflags(struct file *file, unsigned int __user *argp)
 	int err;
 
 	err = vfs_fileattr_get(file->f_path.dentry, &fa);
-	if (err == -EOPNOTSUPP)
-		err = -ENOIOCTLCMD;
 	if (!err)
 		err = put_user(fa.flags, argp);
 	return err;
@@ -335,8 +333,6 @@ 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;
 		}
 	}
 	return err;
@@ -349,8 +345,6 @@ int ioctl_fsgetxattr(struct file *file, void __user *argp)
 	int err;
 
 	err = vfs_fileattr_get(file->f_path.dentry, &fa);
-	if (err == -EOPNOTSUPP)
-		err = -ENOIOCTLCMD;
 	if (!err)
 		err = copy_fsxattr_to_user(&fa, argp);
 
@@ -371,8 +365,6 @@ int ioctl_fssetxattr(struct file *file, void __user *argp)
 		if (!err) {
 			err = vfs_fileattr_set(idmap, dentry, &fa);
 			mnt_drop_write_file(file);
-			if (err == -EOPNOTSUPP)
-				err = -ENOIOCTLCMD;
 		}
 	}
 	return err;
diff --git a/fs/fuse/ioctl.c b/fs/fuse/ioctl.c
index 57032eadca6c..fdc175e93f74 100644
--- a/fs/fuse/ioctl.c
+++ b/fs/fuse/ioctl.c
@@ -536,8 +536,6 @@ int fuse_fileattr_get(struct dentry *dentry, struct file_kattr *fa)
 cleanup:
 	fuse_priv_ioctl_cleanup(inode, ff);
 
-	if (err == -ENOTTY)
-		err = -EOPNOTSUPP;
 	return err;
 }
 
@@ -574,7 +572,5 @@ int fuse_fileattr_set(struct mnt_idmap *idmap,
 cleanup:
 	fuse_priv_ioctl_cleanup(inode, ff);
 
-	if (err == -ENOTTY)
-		err = -EOPNOTSUPP;
 	return err;
 }
diff --git a/fs/overlayfs/copy_up.c b/fs/overlayfs/copy_up.c
index 27396fe63f6d..20c92ea58093 100644
--- a/fs/overlayfs/copy_up.c
+++ b/fs/overlayfs/copy_up.c
@@ -178,7 +178,7 @@ static int ovl_copy_fileattr(struct inode *inode, const struct path *old,
 	err = ovl_real_fileattr_get(old, &oldfa);
 	if (err) {
 		/* Ntfs-3g returns -EINVAL for "no fileattr support" */
-		if (err == -EOPNOTSUPP || err == -EINVAL)
+		if (err == -ENOTTY || err == -EINVAL)
 			return 0;
 		pr_warn("failed to retrieve lower fileattr (%pd2, err=%i)\n",
 			old->dentry, err);
diff --git a/fs/overlayfs/inode.c b/fs/overlayfs/inode.c
index ecb9f2019395..d4722e1b83bc 100644
--- a/fs/overlayfs/inode.c
+++ b/fs/overlayfs/inode.c
@@ -720,7 +720,10 @@ int ovl_real_fileattr_get(const struct path *realpath, struct file_kattr *fa)
 	if (err)
 		return err;
 
-	return vfs_fileattr_get(realpath->dentry, fa);
+	err = vfs_fileattr_get(realpath->dentry, fa);
+	if (err == -ENOIOCTLCMD)
+		err = -ENOTTY;
+	return err;
 }
 
 int ovl_fileattr_get(struct dentry *dentry, struct file_kattr *fa)

-- 
2.51.0

[PATCH 2/2] fs: return EOPNOTSUPP from file_setattr/file_getattr syscalls

[Andrey Albershteyn]

These syscalls call to vfs_fileattr_get/set functions which return
ENOIOCTLCMD if filesystem doesn't support setting file attribute on an
inode. For syscalls EOPNOTSUPP would be more appropriate return error.

Signed-off-by: Andrey Albershteyn <aalbersh@kernel.org>
---
 fs/file_attr.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/fs/file_attr.c b/fs/file_attr.c
index 460b2dd21a85..5e3e2aba97b5 100644
--- a/fs/file_attr.c
+++ b/fs/file_attr.c
@@ -416,6 +416,8 @@ SYSCALL_DEFINE5(file_getattr, int, dfd, const char __user *, filename,
 	}
 
 	error = vfs_fileattr_get(filepath.dentry, &fa);
+	if (error == -ENOIOCTLCMD)
+		error = -EOPNOTSUPP;
 	if (error)
 		return error;
 
@@ -483,6 +485,8 @@ SYSCALL_DEFINE5(file_setattr, int, dfd, const char __user *, filename,
 	if (!error) {
 		error = vfs_fileattr_set(mnt_idmap(filepath.mnt),
 					 filepath.dentry, &fa);
+		if (error == -ENOIOCTLCMD)
+			error = -EOPNOTSUPP;
 		mnt_drop_write(filepath.mnt);
 	}
 

-- 
2.51.0

Re: [PATCH 2/2] fs: return EOPNOTSUPP from file_setattr/file_getattr syscalls

[Arnd Bergmann]

On Wed, Oct 8, 2025, at 14:44, Andrey Albershteyn wrote:
> These syscalls call to vfs_fileattr_get/set functions which return
> ENOIOCTLCMD if filesystem doesn't support setting file attribute on an
> inode. For syscalls EOPNOTSUPP would be more appropriate return error.
>
> Signed-off-by: Andrey Albershteyn <aalbersh@kernel.org>

Reviewed-by: Arnd Bergmann <arnd@arndb.de>

Re: [PATCH 2/2] fs: return EOPNOTSUPP from file_setattr/file_getattr syscalls

[Jan Kara]

On Wed 08-10-25 14:44:18, Andrey Albershteyn wrote:
> These syscalls call to vfs_fileattr_get/set functions which return
> ENOIOCTLCMD if filesystem doesn't support setting file attribute on an
> inode. For syscalls EOPNOTSUPP would be more appropriate return error.
> 
> Signed-off-by: Andrey Albershteyn <aalbersh@kernel.org>

Looks good. Feel free to add:

Reviewed-by: Jan Kara <jack@suse.cz>

								Honza

> ---
>  fs/file_attr.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/fs/file_attr.c b/fs/file_attr.c
> index 460b2dd21a85..5e3e2aba97b5 100644
> --- a/fs/file_attr.c
> +++ b/fs/file_attr.c
> @@ -416,6 +416,8 @@ SYSCALL_DEFINE5(file_getattr, int, dfd, const char __user *, filename,
>  	}
>  
>  	error = vfs_fileattr_get(filepath.dentry, &fa);
> +	if (error == -ENOIOCTLCMD)
> +		error = -EOPNOTSUPP;
>  	if (error)
>  		return error;
>  
> @@ -483,6 +485,8 @@ SYSCALL_DEFINE5(file_setattr, int, dfd, const char __user *, filename,
>  	if (!error) {
>  		error = vfs_fileattr_set(mnt_idmap(filepath.mnt),
>  					 filepath.dentry, &fa);
> +		if (error == -ENOIOCTLCMD)
> +			error = -EOPNOTSUPP;
>  		mnt_drop_write(filepath.mnt);
>  	}
>  
> 
> -- 
> 2.51.0
> 
-- 
Jan Kara <jack@suse.com>
SUSE Labs, CR

Re: [PATCH 2/2] fs: return EOPNOTSUPP from file_setattr/file_getattr syscalls

[Darrick J. Wong]

On Wed, Oct 08, 2025 at 02:44:18PM +0200, Andrey Albershteyn wrote:
> These syscalls call to vfs_fileattr_get/set functions which return
> ENOIOCTLCMD if filesystem doesn't support setting file attribute on an
> inode. For syscalls EOPNOTSUPP would be more appropriate return error.
> 
> Signed-off-by: Andrey Albershteyn <aalbersh@kernel.org>
> ---
>  fs/file_attr.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/fs/file_attr.c b/fs/file_attr.c
> index 460b2dd21a85..5e3e2aba97b5 100644
> --- a/fs/file_attr.c
> +++ b/fs/file_attr.c
> @@ -416,6 +416,8 @@ SYSCALL_DEFINE5(file_getattr, int, dfd, const char __user *, filename,
>  	}
>  
>  	error = vfs_fileattr_get(filepath.dentry, &fa);
> +	if (error == -ENOIOCTLCMD)

Hrm.  Back in 6.17, XFS would return ENOTTY if you called ->fileattr_get
on a special file:

int
xfs_fileattr_get(
	struct dentry		*dentry,
	struct file_kattr	*fa)
{
	struct xfs_inode	*ip = XFS_I(d_inode(dentry));

	if (d_is_special(dentry))
		return -ENOTTY;
	...
}

Given that there are other fileattr_[gs]et implementations out there
that might return ENOTTY (e.g. fuse servers and other externally
maintained filesystems), I think both syscall functions need to check
for that as well:

	if (error == -ENOIOCTLCMD || error == -ENOTTY)
		return -EOPNOTSUPP;

--D

> +		error = -EOPNOTSUPP;
>  	if (error)
>  		return error;
>  
> @@ -483,6 +485,8 @@ SYSCALL_DEFINE5(file_setattr, int, dfd, const char __user *, filename,
>  	if (!error) {
>  		error = vfs_fileattr_set(mnt_idmap(filepath.mnt),
>  					 filepath.dentry, &fa);
> +		if (error == -ENOIOCTLCMD)
> +			error = -EOPNOTSUPP;
>  		mnt_drop_write(filepath.mnt);
>  	}
>  
> 
> -- 
> 2.51.0
> 
> 

Re: [PATCH 2/2] fs: return EOPNOTSUPP from file_setattr/file_getattr syscalls

[Andrey Albershteyn]

On 2025-10-09 10:20:41, Darrick J. Wong wrote:
> On Wed, Oct 08, 2025 at 02:44:18PM +0200, Andrey Albershteyn wrote:
> > These syscalls call to vfs_fileattr_get/set functions which return
> > ENOIOCTLCMD if filesystem doesn't support setting file attribute on an
> > inode. For syscalls EOPNOTSUPP would be more appropriate return error.
> > 
> > Signed-off-by: Andrey Albershteyn <aalbersh@kernel.org>
> > ---
> >  fs/file_attr.c | 4 ++++
> >  1 file changed, 4 insertions(+)
> > 
> > diff --git a/fs/file_attr.c b/fs/file_attr.c
> > index 460b2dd21a85..5e3e2aba97b5 100644
> > --- a/fs/file_attr.c
> > +++ b/fs/file_attr.c
> > @@ -416,6 +416,8 @@ SYSCALL_DEFINE5(file_getattr, int, dfd, const char __user *, filename,
> >  	}
> >  
> >  	error = vfs_fileattr_get(filepath.dentry, &fa);
> > +	if (error == -ENOIOCTLCMD)
> 
> Hrm.  Back in 6.17, XFS would return ENOTTY if you called ->fileattr_get
> on a special file:
> 
> int
> xfs_fileattr_get(
> 	struct dentry		*dentry,
> 	struct file_kattr	*fa)
> {
> 	struct xfs_inode	*ip = XFS_I(d_inode(dentry));
> 
> 	if (d_is_special(dentry))
> 		return -ENOTTY;
> 	...
> }
> 
> Given that there are other fileattr_[gs]et implementations out there
> that might return ENOTTY (e.g. fuse servers and other externally
> maintained filesystems), I think both syscall functions need to check
> for that as well:
> 
> 	if (error == -ENOIOCTLCMD || error == -ENOTTY)
> 		return -EOPNOTSUPP;

Make sense (looks like ubifs, jfs and gfs2 also return ENOTTY for
special files), I haven't found ENOTTY being used for anything else
there

-- 
- Andrey

Re: [PATCH 2/2] fs: return EOPNOTSUPP from file_setattr/file_getattr syscalls

[Christian Brauner]

On Fri, Oct 10, 2025 at 12:05:04PM +0200, Andrey Albershteyn wrote:
> On 2025-10-09 10:20:41, Darrick J. Wong wrote:
> > On Wed, Oct 08, 2025 at 02:44:18PM +0200, Andrey Albershteyn wrote:
> > > These syscalls call to vfs_fileattr_get/set functions which return
> > > ENOIOCTLCMD if filesystem doesn't support setting file attribute on an
> > > inode. For syscalls EOPNOTSUPP would be more appropriate return error.
> > > 
> > > Signed-off-by: Andrey Albershteyn <aalbersh@kernel.org>
> > > ---
> > >  fs/file_attr.c | 4 ++++
> > >  1 file changed, 4 insertions(+)
> > > 
> > > diff --git a/fs/file_attr.c b/fs/file_attr.c
> > > index 460b2dd21a85..5e3e2aba97b5 100644
> > > --- a/fs/file_attr.c
> > > +++ b/fs/file_attr.c
> > > @@ -416,6 +416,8 @@ SYSCALL_DEFINE5(file_getattr, int, dfd, const char __user *, filename,
> > >  	}
> > >  
> > >  	error = vfs_fileattr_get(filepath.dentry, &fa);
> > > +	if (error == -ENOIOCTLCMD)
> > 
> > Hrm.  Back in 6.17, XFS would return ENOTTY if you called ->fileattr_get
> > on a special file:
> > 
> > int
> > xfs_fileattr_get(
> > 	struct dentry		*dentry,
> > 	struct file_kattr	*fa)
> > {
> > 	struct xfs_inode	*ip = XFS_I(d_inode(dentry));
> > 
> > 	if (d_is_special(dentry))
> > 		return -ENOTTY;
> > 	...
> > }
> > 
> > Given that there are other fileattr_[gs]et implementations out there
> > that might return ENOTTY (e.g. fuse servers and other externally
> > maintained filesystems), I think both syscall functions need to check
> > for that as well:
> > 
> > 	if (error == -ENOIOCTLCMD || error == -ENOTTY)
> > 		return -EOPNOTSUPP;
> 
> Make sense (looks like ubifs, jfs and gfs2 also return ENOTTY for
> special files), I haven't found ENOTTY being used for anything else
> there

I'm folding this in.

Re: [PATCH 0/2] Fix to EOPNOTSUPP double conversion in ioctl_setflags()

[Christian Brauner]

On Wed, 08 Oct 2025 14:44:16 +0200, Andrey Albershteyn wrote:
> Revert original double conversion patch from ENOIOCTLCMD to EOPNOSUPP for
> vfs_fileattr_get and vfs_fileattr_set. Instead, convert ENOIOCTLCMD only
> where necessary.
> 
> To: linux-api@vger.kernel.org
> To: linux-fsdevel@vger.kernel.org
> To: linux-kernel@vger.kernel.org
> To: linux-xfs@vger.kernel.org,
> Cc: "Jan Kara" <jack@suse.cz>
> Cc: "Jiri Slaby" <jirislaby@kernel.org>
> Cc: "Christian Brauner" <brauner@kernel.org>
> Cc: "Arnd Bergmann" <arnd@arndb.de>
> 
> [...]

Applied to the vfs.fixes branch of the vfs/vfs.git tree.
Patches in the vfs.fixes branch should appear in linux-next soon.

Please report any outstanding bugs that were missed during review in a
new review to the original patch series allowing us to drop it.

It's encouraged to provide Acked-bys and Reviewed-bys even though the
patch has now been applied. If possible patch trailers will be updated.

Note that commit hashes shown below are subject to change due to rebase,
trailer updates or similar. If in doubt, please check the listed branch.

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs.git
branch: vfs.fixes

[1/2] Revert "fs: make vfs_fileattr_[get|set] return -EOPNOTSUPP"
      https://git.kernel.org/vfs/vfs/c/4dd5b5ac089b
[2/2] fs: return EOPNOTSUPP from file_setattr/file_getattr syscalls
      https://git.kernel.org/vfs/vfs/c/d90ad28e8aa4