Re: [PATCH 12/27] fs: port ->permission() to pass const mnt_idmap
From: Jan Kara
Date: Wed Sep 02 2026 - 11:47:47 EST
On Tue 01-09-26 14:14:37, Christian Brauner wrote:
> Convert to const struct mnt_idmap.
>
> A mount's idmapping is immutable. The only thing that is allowed to be
> modified afterwards is the reference count and that is hidden behind
> mnt_idmap_get() and mnt_idmap_put(). Everything else only ever reads
> from the idmapping. This is the same model that struct cred uses and the
> idmapping is also rather sensitive.
>
> So make the idmap argument const wherever we can. The conversion is done
> from the bottom up so callers can continue to pass a non-const pointer
> to a const parameter until the conversion is finished.
>
> No functional changes.
>
> Signed-off-by: Christian Brauner (Amutable) <brauner@xxxxxxxxxx>
Looks good. Feel free to add:
Reviewed-by: Jan Kara <jack@xxxxxxx>
Honza
> ---
> Documentation/filesystems/locking.rst | 2 +-
> Documentation/filesystems/vfs.rst | 2 +-
> fs/afs/internal.h | 2 +-
> fs/afs/security.c | 2 +-
> fs/attr.c | 2 +-
> fs/autofs/root.c | 4 ++--
> fs/bad_inode.c | 2 +-
> fs/btrfs/inode.c | 2 +-
> fs/btrfs/ioctl.c | 2 +-
> fs/ceph/inode.c | 2 +-
> fs/ceph/super.h | 2 +-
> fs/coda/coda_linux.h | 2 +-
> fs/coda/dir.c | 2 +-
> fs/coda/pioctl.c | 4 ++--
> fs/ecryptfs/inode.c | 2 +-
> fs/failfs.c | 2 +-
> fs/fuse/dir.c | 2 +-
> fs/gfs2/inode.c | 2 +-
> fs/gfs2/inode.h | 2 +-
> fs/hostfs/hostfs_kern.c | 2 +-
> fs/internal.h | 2 +-
> fs/kernfs/inode.c | 2 +-
> fs/kernfs/kernfs-internal.h | 2 +-
> fs/namei.c | 22 +++++++++++-----------
> fs/nfs/dir.c | 2 +-
> fs/nilfs2/inode.c | 2 +-
> fs/nilfs2/nilfs.h | 2 +-
> fs/ocfs2/file.c | 2 +-
> fs/ocfs2/file.h | 2 +-
> fs/orangefs/inode.c | 2 +-
> fs/orangefs/orangefs-kernel.h | 2 +-
> fs/overlayfs/inode.c | 2 +-
> fs/overlayfs/overlayfs.h | 2 +-
> fs/proc/base.c | 4 ++--
> fs/proc/fd.c | 4 ++--
> fs/proc/fd.h | 2 +-
> fs/proc/proc_sysctl.c | 2 +-
> fs/smb/client/cifsfs.c | 2 +-
> fs/smb/server/vfs.c | 2 +-
> fs/smb/server/vfs.h | 2 +-
> fs/tracefs/inode.c | 2 +-
> include/linux/fs.h | 8 ++++----
> include/linux/nfs_fs.h | 2 +-
> security/selinux/selinuxfs.c | 2 +-
> 44 files changed, 61 insertions(+), 61 deletions(-)
>
> diff --git a/Documentation/filesystems/locking.rst b/Documentation/filesystems/locking.rst
> index 844d65eb47a5..5af7d3bfcd5e 100644
> --- a/Documentation/filesystems/locking.rst
> +++ b/Documentation/filesystems/locking.rst
> @@ -74,7 +74,7 @@ prototypes::
> int (*readlink) (struct dentry *, char __user *,int);
> const char *(*get_link) (struct dentry *, struct inode *, struct delayed_call *);
> void (*truncate) (struct inode *);
> - int (*permission) (struct mnt_idmap *, struct inode *, int, unsigned int);
> + int (*permission) (const struct mnt_idmap *, struct inode *, int, unsigned int);
> struct posix_acl * (*get_inode_acl)(struct inode *, int, bool);
> int (*setattr) (struct mnt_idmap *, struct dentry *, struct iattr *);
> int (*getattr) (struct mnt_idmap *, const struct path *, struct kstat *, u32, unsigned int);
> diff --git a/Documentation/filesystems/vfs.rst b/Documentation/filesystems/vfs.rst
> index d3a93eec3945..b7e476f70185 100644
> --- a/Documentation/filesystems/vfs.rst
> +++ b/Documentation/filesystems/vfs.rst
> @@ -428,7 +428,7 @@ As of kernel 2.6.22, the following members are defined:
> int (*readlink) (struct dentry *, char __user *,int);
> const char *(*get_link) (struct dentry *, struct inode *,
> struct delayed_call *);
> - int (*permission) (struct mnt_idmap *, struct inode *, int);
> + int (*permission) (const struct mnt_idmap *, struct inode *, int);
> struct posix_acl * (*get_inode_acl)(struct inode *, int, bool);
> int (*setattr) (struct mnt_idmap *, struct dentry *, struct iattr *);
> int (*getattr) (struct mnt_idmap *, const struct path *, struct kstat *, u32, unsigned int);
> diff --git a/fs/afs/internal.h b/fs/afs/internal.h
> index 290873bac89b..e772da2a15f2 100644
> --- a/fs/afs/internal.h
> +++ b/fs/afs/internal.h
> @@ -1530,7 +1530,7 @@ extern void afs_cache_permit(struct afs_vnode *, struct key *, unsigned int,
> extern struct key *afs_request_key(struct afs_cell *);
> extern struct key *afs_request_key_rcu(struct afs_cell *);
> extern int afs_check_permit(struct afs_vnode *, struct key *, afs_access_t *);
> -extern int afs_permission(struct mnt_idmap *, struct inode *, int);
> +extern int afs_permission(const struct mnt_idmap *, struct inode *, int);
> extern void __exit afs_clean_up_permit_cache(void);
>
> /*
> diff --git a/fs/afs/security.c b/fs/afs/security.c
> index 6d00d62a65ed..fd040f7c6766 100644
> --- a/fs/afs/security.c
> +++ b/fs/afs/security.c
> @@ -428,7 +428,7 @@ int afs_check_permit(struct afs_vnode *vnode, struct key *key,
> * - AFS ACLs are attached to directories only, and a file is controlled by its
> * parent directory's ACL
> */
> -int afs_permission(struct mnt_idmap *idmap, struct inode *inode,
> +int afs_permission(const struct mnt_idmap *idmap, struct inode *inode,
> int mask)
> {
> struct afs_vnode *vnode = AFS_FS_I(inode);
> diff --git a/fs/attr.c b/fs/attr.c
> index 23f1347ff240..c5033afe04bf 100644
> --- a/fs/attr.c
> +++ b/fs/attr.c
> @@ -369,7 +369,7 @@ void setattr_copy(const struct mnt_idmap *idmap, struct inode *inode,
> }
> EXPORT_SYMBOL(setattr_copy);
>
> -int may_setattr(struct mnt_idmap *idmap, struct inode *inode,
> +int may_setattr(const struct mnt_idmap *idmap, struct inode *inode,
> unsigned int ia_valid)
> {
> int error;
> diff --git a/fs/autofs/root.c b/fs/autofs/root.c
> index b36439f4521e..3158df448025 100644
> --- a/fs/autofs/root.c
> +++ b/fs/autofs/root.c
> @@ -11,7 +11,7 @@
>
> #include "autofs_i.h"
>
> -static int autofs_dir_permission(struct mnt_idmap *, struct inode *, int);
> +static int autofs_dir_permission(const struct mnt_idmap *, struct inode *, int);
> static int autofs_dir_symlink(struct mnt_idmap *, struct inode *,
> struct dentry *, const char *);
> static int autofs_dir_unlink(struct inode *, struct dentry *);
> @@ -552,7 +552,7 @@ static struct dentry *autofs_lookup(struct inode *dir,
> return NULL;
> }
>
> -static int autofs_dir_permission(struct mnt_idmap *idmap,
> +static int autofs_dir_permission(const struct mnt_idmap *idmap,
> struct inode *inode, int mask)
> {
> if (mask & MAY_WRITE) {
> diff --git a/fs/bad_inode.c b/fs/bad_inode.c
> index 486c40f73e51..c2cfa9395bc9 100644
> --- a/fs/bad_inode.c
> +++ b/fs/bad_inode.c
> @@ -89,7 +89,7 @@ static int bad_inode_readlink(struct dentry *dentry, char __user *buffer,
> return -EIO;
> }
>
> -static int bad_inode_permission(struct mnt_idmap *idmap,
> +static int bad_inode_permission(const struct mnt_idmap *idmap,
> struct inode *inode, int mask)
> {
> return -EIO;
> diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
> index d5a78d9027e2..7bf38f069116 100644
> --- a/fs/btrfs/inode.c
> +++ b/fs/btrfs/inode.c
> @@ -9375,7 +9375,7 @@ int btrfs_prealloc_file_range_trans(struct inode *inode,
> * we are marking them with IOP_FASTPERM_MAY_EXEC, allowing path lookup to
> * elide calls here.
> */
> -static int btrfs_permission(struct mnt_idmap *idmap,
> +static int btrfs_permission(const struct mnt_idmap *idmap,
> struct inode *inode, int mask)
> {
> struct btrfs_root *root = BTRFS_I(inode)->root;
> diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
> index 8eacdc2ee4de..9d6302547b12 100644
> --- a/fs/btrfs/ioctl.c
> +++ b/fs/btrfs/ioctl.c
> @@ -1726,7 +1726,7 @@ static noinline int btrfs_search_path_in_tree(struct btrfs_root *root, u64 dirid
> return 0;
> }
>
> -static int btrfs_search_path_in_tree_user(struct mnt_idmap *idmap,
> +static int btrfs_search_path_in_tree_user(const struct mnt_idmap *idmap,
> struct inode *inode,
> struct btrfs_ioctl_ino_lookup_user_args *args)
> {
> diff --git a/fs/ceph/inode.c b/fs/ceph/inode.c
> index 3921b601ad59..b8527f67e3f0 100644
> --- a/fs/ceph/inode.c
> +++ b/fs/ceph/inode.c
> @@ -3098,7 +3098,7 @@ int ceph_do_getvxattr(struct inode *inode, const char *name, void *value,
> * Check inode permissions. We verify we have a valid value for
> * the AUTH cap, then call the generic handler.
> */
> -int ceph_permission(struct mnt_idmap *idmap, struct inode *inode,
> +int ceph_permission(const struct mnt_idmap *idmap, struct inode *inode,
> int mask)
> {
> int err;
> diff --git a/fs/ceph/super.h b/fs/ceph/super.h
> index e9a9d5737c80..ef9861797eb2 100644
> --- a/fs/ceph/super.h
> +++ b/fs/ceph/super.h
> @@ -1166,7 +1166,7 @@ static inline int ceph_do_getattr(struct inode *inode, int mask, bool force)
> {
> return __ceph_do_getattr(inode, NULL, mask, force);
> }
> -extern int ceph_permission(struct mnt_idmap *idmap,
> +extern int ceph_permission(const struct mnt_idmap *idmap,
> struct inode *inode, int mask);
>
> struct ceph_iattr {
> diff --git a/fs/coda/coda_linux.h b/fs/coda/coda_linux.h
> index dd6277d87afb..5ee6cedd3865 100644
> --- a/fs/coda/coda_linux.h
> +++ b/fs/coda/coda_linux.h
> @@ -46,7 +46,7 @@ extern const struct file_operations coda_ioctl_operations;
> /* operations shared over more than one file */
> int coda_open(struct inode *i, struct file *f);
> int coda_release(struct inode *i, struct file *f);
> -int coda_permission(struct mnt_idmap *idmap, struct inode *inode,
> +int coda_permission(const struct mnt_idmap *idmap, struct inode *inode,
> int mask);
> int coda_revalidate_inode(struct inode *);
> int coda_getattr(struct mnt_idmap *, const struct path *, struct kstat *,
> diff --git a/fs/coda/dir.c b/fs/coda/dir.c
> index 67148edfadee..e8db5960b61b 100644
> --- a/fs/coda/dir.c
> +++ b/fs/coda/dir.c
> @@ -73,7 +73,7 @@ static struct dentry *coda_lookup(struct inode *dir, struct dentry *entry, unsig
> }
>
>
> -int coda_permission(struct mnt_idmap *idmap, struct inode *inode,
> +int coda_permission(const struct mnt_idmap *idmap, struct inode *inode,
> int mask)
> {
> int error;
> diff --git a/fs/coda/pioctl.c b/fs/coda/pioctl.c
> index 36e35c15561a..c457e9bab94b 100644
> --- a/fs/coda/pioctl.c
> +++ b/fs/coda/pioctl.c
> @@ -24,7 +24,7 @@
> #include "coda_linux.h"
>
> /* pioctl ops */
> -static int coda_ioctl_permission(struct mnt_idmap *idmap,
> +static int coda_ioctl_permission(const struct mnt_idmap *idmap,
> struct inode *inode, int mask);
> static long coda_pioctl(struct file *filp, unsigned int cmd,
> unsigned long user_data);
> @@ -41,7 +41,7 @@ const struct file_operations coda_ioctl_operations = {
> };
>
> /* the coda pioctl inode ops */
> -static int coda_ioctl_permission(struct mnt_idmap *idmap,
> +static int coda_ioctl_permission(const struct mnt_idmap *idmap,
> struct inode *inode, int mask)
> {
> return (mask & MAY_EXEC) ? -EACCES : 0;
> diff --git a/fs/ecryptfs/inode.c b/fs/ecryptfs/inode.c
> index 525297c7ebd8..6dafca14ca78 100644
> --- a/fs/ecryptfs/inode.c
> +++ b/fs/ecryptfs/inode.c
> @@ -849,7 +849,7 @@ int ecryptfs_truncate(struct dentry *dentry, loff_t new_length)
> }
>
> static int
> -ecryptfs_permission(struct mnt_idmap *idmap, struct inode *inode,
> +ecryptfs_permission(const struct mnt_idmap *idmap, struct inode *inode,
> int mask)
> {
> return inode_permission(&nop_mnt_idmap,
> diff --git a/fs/failfs.c b/fs/failfs.c
> index 66a36da3d236..cec6cad99eb2 100644
> --- a/fs/failfs.c
> +++ b/fs/failfs.c
> @@ -22,7 +22,7 @@ bool failfs_mnt(const struct vfsmount *mnt)
> return mnt->mnt_sb == failfs_root_path.mnt->mnt_sb;
> }
>
> -static int failfs_permission(struct mnt_idmap *idmap, struct inode *inode,
> +static int failfs_permission(const struct mnt_idmap *idmap, struct inode *inode,
> int mask)
> {
> return -EOPNOTSUPP;
> diff --git a/fs/fuse/dir.c b/fs/fuse/dir.c
> index 7a204f55ca84..4b87973c727d 100644
> --- a/fs/fuse/dir.c
> +++ b/fs/fuse/dir.c
> @@ -1763,7 +1763,7 @@ static int fuse_perm_getattr(struct inode *inode, int mask)
> * access request is sent. Execute permission is still checked
> * locally based on file mode.
> */
> -static int fuse_permission(struct mnt_idmap *idmap,
> +static int fuse_permission(const struct mnt_idmap *idmap,
> struct inode *inode, int mask)
> {
> struct fuse_conn *fc = get_fuse_conn(inode);
> diff --git a/fs/gfs2/inode.c b/fs/gfs2/inode.c
> index f361876c5583..1b1d22abe1d4 100644
> --- a/fs/gfs2/inode.c
> +++ b/fs/gfs2/inode.c
> @@ -1963,7 +1963,7 @@ static const char *gfs2_get_link(struct dentry *dentry,
> * Returns: errno
> */
>
> -int gfs2_permission(struct mnt_idmap *idmap, struct inode *inode,
> +int gfs2_permission(const struct mnt_idmap *idmap, struct inode *inode,
> int mask)
> {
> int may_not_block = mask & MAY_NOT_BLOCK;
> diff --git a/fs/gfs2/inode.h b/fs/gfs2/inode.h
> index 2fcd96dd1361..373473eb091c 100644
> --- a/fs/gfs2/inode.h
> +++ b/fs/gfs2/inode.h
> @@ -97,7 +97,7 @@ int gfs2_dinode_dealloc(struct gfs2_inode *ip);
>
> struct inode *gfs2_lookupi(struct inode *dir, const struct qstr *name,
> int is_root);
> -int gfs2_permission(struct mnt_idmap *idmap,
> +int gfs2_permission(const struct mnt_idmap *idmap,
> struct inode *inode, int mask);
> struct inode *gfs2_lookup_meta(struct inode *dip, const char *name);
> void gfs2_dinode_out(const struct gfs2_inode *ip, void *buf);
> diff --git a/fs/hostfs/hostfs_kern.c b/fs/hostfs/hostfs_kern.c
> index 7add056d47d8..0d5c5f11f913 100644
> --- a/fs/hostfs/hostfs_kern.c
> +++ b/fs/hostfs/hostfs_kern.c
> @@ -774,7 +774,7 @@ static int hostfs_rename2(struct mnt_idmap *idmap,
> return err;
> }
>
> -static int hostfs_permission(struct mnt_idmap *idmap,
> +static int hostfs_permission(const struct mnt_idmap *idmap,
> struct inode *ino, int desired)
> {
> char *name;
> diff --git a/fs/internal.h b/fs/internal.h
> index 161b0cafe17f..a502b1fbacd2 100644
> --- a/fs/internal.h
> +++ b/fs/internal.h
> @@ -55,7 +55,7 @@ extern int filename_lookup(int dfd, struct filename *name, unsigned flags,
> struct path *path, const struct path *root);
> int filename_rmdir(int dfd, struct filename *name);
> int filename_unlinkat(int dfd, struct filename *name);
> -int may_linkat(struct mnt_idmap *idmap, const struct path *link);
> +int may_linkat(const struct mnt_idmap *idmap, const struct path *link);
> int filename_renameat2(int olddfd, struct filename *oldname, int newdfd,
> struct filename *newname, unsigned int flags);
> int filename_mkdirat(int dfd, struct filename *name, umode_t mode);
> diff --git a/fs/kernfs/inode.c b/fs/kernfs/inode.c
> index 237dcdd73fc2..d53d104e54d5 100644
> --- a/fs/kernfs/inode.c
> +++ b/fs/kernfs/inode.c
> @@ -272,7 +272,7 @@ void kernfs_evict_inode(struct inode *inode)
> kernfs_put(kn);
> }
>
> -int kernfs_iop_permission(struct mnt_idmap *idmap,
> +int kernfs_iop_permission(const struct mnt_idmap *idmap,
> struct inode *inode, int mask)
> {
> struct kernfs_node *kn;
> diff --git a/fs/kernfs/kernfs-internal.h b/fs/kernfs/kernfs-internal.h
> index aa784b540b36..0f6f412213f6 100644
> --- a/fs/kernfs/kernfs-internal.h
> +++ b/fs/kernfs/kernfs-internal.h
> @@ -171,7 +171,7 @@ extern struct kmem_cache *kernfs_node_cache, *kernfs_iattrs_cache;
> */
> extern const struct xattr_handler * const kernfs_xattr_handlers[];
> void kernfs_evict_inode(struct inode *inode);
> -int kernfs_iop_permission(struct mnt_idmap *idmap,
> +int kernfs_iop_permission(const struct mnt_idmap *idmap,
> struct inode *inode, int mask);
> int kernfs_iop_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
> struct iattr *iattr);
> diff --git a/fs/namei.c b/fs/namei.c
> index db82daec3646..f5e00ae41ed4 100644
> --- a/fs/namei.c
> +++ b/fs/namei.c
> @@ -371,7 +371,7 @@ struct filename *complete_getname(struct delayed_filename *v)
> * On non-idmapped mounts or if permission checking is to be performed on the
> * raw inode simply pass @nop_mnt_idmap.
> */
> -static int check_acl(struct mnt_idmap *idmap,
> +static int check_acl(const struct mnt_idmap *idmap,
> struct inode *inode, int mask)
> {
> #ifdef CONFIG_FS_POSIX_ACL
> @@ -435,7 +435,7 @@ static inline bool no_acl_inode(struct inode *inode)
> * On non-idmapped mounts or if permission checking is to be performed on the
> * raw inode simply pass @nop_mnt_idmap.
> */
> -static int acl_permission_check(struct mnt_idmap *idmap,
> +static int acl_permission_check(const struct mnt_idmap *idmap,
> struct inode *inode, int mask)
> {
> unsigned int mode = inode->i_mode;
> @@ -518,7 +518,7 @@ static int acl_permission_check(struct mnt_idmap *idmap,
> * On non-idmapped mounts or if permission checking is to be performed on the
> * raw inode simply pass @nop_mnt_idmap.
> */
> -int generic_permission(struct mnt_idmap *idmap, struct inode *inode,
> +int generic_permission(const struct mnt_idmap *idmap, struct inode *inode,
> int mask)
> {
> int ret;
> @@ -575,7 +575,7 @@ EXPORT_SYMBOL(generic_permission);
> * flag in inode->i_opflags, that says "this has not special
> * permission function, use the fast case".
> */
> -static inline int do_inode_permission(struct mnt_idmap *idmap,
> +static inline int do_inode_permission(const struct mnt_idmap *idmap,
> struct inode *inode, int mask)
> {
> if (unlikely(!(inode->i_opflags & IOP_FASTPERM))) {
> @@ -625,7 +625,7 @@ static int sb_permission(struct super_block *sb, struct inode *inode, int mask)
> *
> * When checking for MAY_APPEND, MAY_WRITE must also be set in @mask.
> */
> -int inode_permission(struct mnt_idmap *idmap,
> +int inode_permission(const struct mnt_idmap *idmap,
> struct inode *inode, int mask)
> {
> int retval;
> @@ -680,7 +680,7 @@ EXPORT_SYMBOL(inode_permission);
> * on IOP_FASTPERM can still get the optimization if they set IOP_FASTPERM_MAY_EXEC
> * on their directory inodes.
> */
> -static __always_inline int lookup_inode_permission_may_exec(struct mnt_idmap *idmap,
> +static __always_inline int lookup_inode_permission_may_exec(const struct mnt_idmap *idmap,
> struct inode *inode, int mask)
> {
> /* Lookup already checked this to return -ENOTDIR */
> @@ -1314,7 +1314,7 @@ static inline int may_follow_link(struct nameidata *nd, const struct inode *inod
> *
> * Otherwise returns true.
> */
> -static bool safe_hardlink_source(struct mnt_idmap *idmap,
> +static bool safe_hardlink_source(const struct mnt_idmap *idmap,
> struct inode *inode)
> {
> umode_t mode = inode->i_mode;
> @@ -1357,7 +1357,7 @@ static bool safe_hardlink_source(struct mnt_idmap *idmap,
> *
> * Returns 0 if successful, -ve on error.
> */
> -int may_linkat(struct mnt_idmap *idmap, const struct path *link)
> +int may_linkat(const struct mnt_idmap *idmap, const struct path *link)
> {
> struct inode *inode = link->dentry->d_inode;
>
> @@ -1952,7 +1952,7 @@ static struct dentry *lookup_slow_killable(const struct qstr *name,
> return res;
> }
>
> -static inline int may_lookup(struct mnt_idmap *idmap,
> +static inline int may_lookup(const struct mnt_idmap *idmap,
> struct nameidata *restrict nd)
> {
> int err, mask;
> @@ -4228,7 +4228,7 @@ bool may_open_dev(const struct path *path)
> !(path->mnt->mnt_sb->s_iflags & SB_I_NODEV);
> }
>
> -static int may_open(struct mnt_idmap *idmap, const struct path *path,
> +static int may_open(const struct mnt_idmap *idmap, const struct path *path,
> int acc_mode, int flag)
> {
> struct dentry *dentry = path->dentry;
> @@ -4312,7 +4312,7 @@ static inline int open_to_namei_flags(int flag)
> return flag;
> }
>
> -static int may_o_create(struct mnt_idmap *idmap,
> +static int may_o_create(const struct mnt_idmap *idmap,
> const struct path *dir, struct dentry *dentry,
> umode_t mode)
> {
> diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
> index 49394123bd09..7574bc2fb677 100644
> --- a/fs/nfs/dir.c
> +++ b/fs/nfs/dir.c
> @@ -3393,7 +3393,7 @@ static int nfs_execute_ok(struct inode *inode, int mask)
> return ret;
> }
>
> -int nfs_permission(struct mnt_idmap *idmap,
> +int nfs_permission(const struct mnt_idmap *idmap,
> struct inode *inode,
> int mask)
> {
> diff --git a/fs/nilfs2/inode.c b/fs/nilfs2/inode.c
> index 34e6096069ad..9342f651bf9b 100644
> --- a/fs/nilfs2/inode.c
> +++ b/fs/nilfs2/inode.c
> @@ -943,7 +943,7 @@ int nilfs_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
> return err;
> }
>
> -int nilfs_permission(struct mnt_idmap *idmap, struct inode *inode,
> +int nilfs_permission(const struct mnt_idmap *idmap, struct inode *inode,
> int mask)
> {
> struct nilfs_root *root = NILFS_I(inode)->i_root;
> diff --git a/fs/nilfs2/nilfs.h b/fs/nilfs2/nilfs.h
> index 4fc42d3787a4..0eaa191f70b8 100644
> --- a/fs/nilfs2/nilfs.h
> +++ b/fs/nilfs2/nilfs.h
> @@ -302,7 +302,7 @@ extern void nilfs_evict_inode(struct inode *);
> extern int nilfs_setattr(struct mnt_idmap *, struct dentry *,
> struct iattr *);
> extern void nilfs_write_failed(struct address_space *mapping, loff_t to);
> -int nilfs_permission(struct mnt_idmap *idmap, struct inode *inode,
> +int nilfs_permission(const struct mnt_idmap *idmap, struct inode *inode,
> int mask);
> int nilfs_load_inode_block(struct inode *inode, struct buffer_head **pbh);
> extern int nilfs_inode_dirty(struct inode *);
> diff --git a/fs/ocfs2/file.c b/fs/ocfs2/file.c
> index d6e977ba6565..24bbf607546c 100644
> --- a/fs/ocfs2/file.c
> +++ b/fs/ocfs2/file.c
> @@ -1349,7 +1349,7 @@ int ocfs2_getattr(struct mnt_idmap *idmap, const struct path *path,
> return err;
> }
>
> -int ocfs2_permission(struct mnt_idmap *idmap, struct inode *inode,
> +int ocfs2_permission(const struct mnt_idmap *idmap, struct inode *inode,
> int mask)
> {
> int ret, had_lock;
> diff --git a/fs/ocfs2/file.h b/fs/ocfs2/file.h
> index 41e65e45a9f3..08e4d6796531 100644
> --- a/fs/ocfs2/file.h
> +++ b/fs/ocfs2/file.h
> @@ -54,7 +54,7 @@ int ocfs2_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
> struct iattr *attr);
> int ocfs2_getattr(struct mnt_idmap *idmap, const struct path *path,
> struct kstat *stat, u32 request_mask, unsigned int flags);
> -int ocfs2_permission(struct mnt_idmap *idmap,
> +int ocfs2_permission(const struct mnt_idmap *idmap,
> struct inode *inode,
> int mask);
>
> diff --git a/fs/orangefs/inode.c b/fs/orangefs/inode.c
> index cd3273c88e03..8e6eeec501bc 100644
> --- a/fs/orangefs/inode.c
> +++ b/fs/orangefs/inode.c
> @@ -872,7 +872,7 @@ int orangefs_getattr(struct mnt_idmap *idmap, const struct path *path,
> return ret;
> }
>
> -int orangefs_permission(struct mnt_idmap *idmap,
> +int orangefs_permission(const struct mnt_idmap *idmap,
> struct inode *inode, int mask)
> {
> int ret;
> diff --git a/fs/orangefs/orangefs-kernel.h b/fs/orangefs/orangefs-kernel.h
> index 1451fc2c1917..c582ceffb26e 100644
> --- a/fs/orangefs/orangefs-kernel.h
> +++ b/fs/orangefs/orangefs-kernel.h
> @@ -357,7 +357,7 @@ int orangefs_setattr(struct mnt_idmap *, struct dentry *, struct iattr *);
> int orangefs_getattr(struct mnt_idmap *idmap, const struct path *path,
> struct kstat *stat, u32 request_mask, unsigned int flags);
>
> -int orangefs_permission(struct mnt_idmap *idmap,
> +int orangefs_permission(const struct mnt_idmap *idmap,
> struct inode *inode, int mask);
>
> int orangefs_update_time(struct inode *inode, enum fs_update_time type,
> diff --git a/fs/overlayfs/inode.c b/fs/overlayfs/inode.c
> index 0364e7d08ad7..1166381f1852 100644
> --- a/fs/overlayfs/inode.c
> +++ b/fs/overlayfs/inode.c
> @@ -303,7 +303,7 @@ int ovl_getattr(struct mnt_idmap *idmap, const struct path *path,
> return err;
> }
>
> -int ovl_permission(struct mnt_idmap *idmap,
> +int ovl_permission(const struct mnt_idmap *idmap,
> struct inode *inode, int mask)
> {
> struct inode *upperinode = ovl_inode_upper(inode);
> diff --git a/fs/overlayfs/overlayfs.h b/fs/overlayfs/overlayfs.h
> index 6508f30aaaca..513ba93c7d1b 100644
> --- a/fs/overlayfs/overlayfs.h
> +++ b/fs/overlayfs/overlayfs.h
> @@ -802,7 +802,7 @@ int ovl_set_nlink_lower(struct dentry *dentry);
> unsigned int ovl_get_nlink(struct ovl_fs *ofs, struct dentry *lowerdentry,
> struct dentry *upperdentry,
> unsigned int fallback);
> -int ovl_permission(struct mnt_idmap *idmap, struct inode *inode,
> +int ovl_permission(const struct mnt_idmap *idmap, struct inode *inode,
> int mask);
>
> #ifdef CONFIG_FS_POSIX_ACL
> diff --git a/fs/proc/base.c b/fs/proc/base.c
> index 6a39de424f62..8dc43c846298 100644
> --- a/fs/proc/base.c
> +++ b/fs/proc/base.c
> @@ -743,7 +743,7 @@ static bool has_pid_permissions(struct proc_fs_info *fs_info,
> }
>
>
> -static int proc_pid_permission(struct mnt_idmap *idmap,
> +static int proc_pid_permission(const struct mnt_idmap *idmap,
> struct inode *inode, int mask)
> {
> struct proc_fs_info *fs_info = proc_sb_info(inode->i_sb);
> @@ -3607,7 +3607,7 @@ int proc_pid_readdir(struct file *file, struct dir_context *ctx)
> * This function makes sure that the node is always accessible for members of
> * same thread group.
> */
> -static int proc_tid_comm_permission(struct mnt_idmap *idmap,
> +static int proc_tid_comm_permission(const struct mnt_idmap *idmap,
> struct inode *inode, int mask)
> {
> bool is_same_tgroup;
> diff --git a/fs/proc/fd.c b/fs/proc/fd.c
> index 0f9a1556f2a3..0653bceb730d 100644
> --- a/fs/proc/fd.c
> +++ b/fs/proc/fd.c
> @@ -82,7 +82,7 @@ static int seq_fdinfo_open(struct inode *inode, struct file *file)
> * that the current task has PTRACE_MODE_READ in addition to the normal
> * POSIX-like checks.
> */
> -static int proc_fdinfo_permission(struct mnt_idmap *idmap, struct inode *inode,
> +static int proc_fdinfo_permission(const struct mnt_idmap *idmap, struct inode *inode,
> int mask)
> {
> bool allowed = false;
> @@ -323,7 +323,7 @@ static struct dentry *proc_lookupfd(struct inode *dir, struct dentry *dentry,
> * /proc/pid/fd needs a special permission handler so that a process can still
> * access /proc/self/fd after it has executed a setuid().
> */
> -int proc_fd_permission(struct mnt_idmap *idmap,
> +int proc_fd_permission(const struct mnt_idmap *idmap,
> struct inode *inode, int mask)
> {
> struct task_struct *p;
> diff --git a/fs/proc/fd.h b/fs/proc/fd.h
> index 7e7265f7e06f..77f2e4f38592 100644
> --- a/fs/proc/fd.h
> +++ b/fs/proc/fd.h
> @@ -10,7 +10,7 @@ extern const struct inode_operations proc_fd_inode_operations;
> extern const struct file_operations proc_fdinfo_operations;
> extern const struct inode_operations proc_fdinfo_inode_operations;
>
> -extern int proc_fd_permission(struct mnt_idmap *idmap,
> +extern int proc_fd_permission(const struct mnt_idmap *idmap,
> struct inode *inode, int mask);
>
> static inline unsigned int proc_fd(struct inode *inode)
> diff --git a/fs/proc/proc_sysctl.c b/fs/proc/proc_sysctl.c
> index 04a382178c65..5315d891f244 100644
> --- a/fs/proc/proc_sysctl.c
> +++ b/fs/proc/proc_sysctl.c
> @@ -788,7 +788,7 @@ static int proc_sys_readdir(struct file *file, struct dir_context *ctx)
> return 0;
> }
>
> -static int proc_sys_permission(struct mnt_idmap *idmap,
> +static int proc_sys_permission(const struct mnt_idmap *idmap,
> struct inode *inode, int mask)
> {
> /*
> diff --git a/fs/smb/client/cifsfs.c b/fs/smb/client/cifsfs.c
> index 7ecd70efdfea..b1ecbcfb154e 100644
> --- a/fs/smb/client/cifsfs.c
> +++ b/fs/smb/client/cifsfs.c
> @@ -402,7 +402,7 @@ static long cifs_fallocate(struct file *file, int mode, loff_t off, loff_t len)
> return rc;
> }
>
> -static int cifs_permission(struct mnt_idmap *idmap,
> +static int cifs_permission(const struct mnt_idmap *idmap,
> struct inode *inode, int mask)
> {
> unsigned int sbflags = cifs_sb_flags(CIFS_SB(inode));
> diff --git a/fs/smb/server/vfs.c b/fs/smb/server/vfs.c
> index cb52dce113b9..0361de56edc2 100644
> --- a/fs/smb/server/vfs.c
> +++ b/fs/smb/server/vfs.c
> @@ -115,7 +115,7 @@ static int ksmbd_vfs_path_lookup(struct ksmbd_share_config *share_conf,
> return 0;
> }
>
> -void ksmbd_vfs_query_maximal_access(struct mnt_idmap *idmap,
> +void ksmbd_vfs_query_maximal_access(const struct mnt_idmap *idmap,
> struct dentry *dentry, __le32 *daccess)
> {
> *daccess = cpu_to_le32(FILE_READ_ATTRIBUTES | READ_CONTROL);
> diff --git a/fs/smb/server/vfs.h b/fs/smb/server/vfs.h
> index 9f4b003166e5..9c8b5b288926 100644
> --- a/fs/smb/server/vfs.h
> +++ b/fs/smb/server/vfs.h
> @@ -74,7 +74,7 @@ struct ksmbd_kstat {
> };
>
> int ksmbd_vfs_lock_parent(struct dentry *parent, struct dentry *child);
> -void ksmbd_vfs_query_maximal_access(struct mnt_idmap *idmap,
> +void ksmbd_vfs_query_maximal_access(const struct mnt_idmap *idmap,
> struct dentry *dentry, __le32 *daccess);
> int ksmbd_vfs_create(struct ksmbd_work *work, const char *name, umode_t mode);
> int ksmbd_vfs_mkdir(struct ksmbd_work *work, const char *name, umode_t mode);
> diff --git a/fs/tracefs/inode.c b/fs/tracefs/inode.c
> index f3d6188a3b7b..7cf32384ad50 100644
> --- a/fs/tracefs/inode.c
> +++ b/fs/tracefs/inode.c
> @@ -189,7 +189,7 @@ static void set_tracefs_inode_owner(struct inode *inode)
> inode->i_gid = gid;
> }
>
> -static int tracefs_permission(struct mnt_idmap *idmap,
> +static int tracefs_permission(const struct mnt_idmap *idmap,
> struct inode *inode, int mask)
> {
> set_tracefs_inode_owner(inode);
> diff --git a/include/linux/fs.h b/include/linux/fs.h
> index 91a23c8dbbf6..f815594dd8cb 100644
> --- a/include/linux/fs.h
> +++ b/include/linux/fs.h
> @@ -1994,7 +1994,7 @@ enum fs_update_time {
> struct inode_operations {
> struct dentry * (*lookup) (struct inode *,struct dentry *, unsigned int);
> const char * (*get_link) (struct dentry *, struct inode *, struct delayed_call *);
> - int (*permission) (struct mnt_idmap *, struct inode *, int);
> + int (*permission) (const struct mnt_idmap *, struct inode *, int);
> struct posix_acl * (*get_inode_acl)(struct inode *, int, bool);
>
> int (*readlink) (struct dentry *, char __user *,int);
> @@ -2709,8 +2709,8 @@ static inline int bmap(struct inode *inode, sector_t *block)
>
> int notify_change(struct mnt_idmap *, struct dentry *,
> struct iattr *, struct delegated_inode *);
> -int inode_permission(struct mnt_idmap *, struct inode *, int);
> -int generic_permission(struct mnt_idmap *, struct inode *, int);
> +int inode_permission(const struct mnt_idmap *, struct inode *, int);
> +int generic_permission(const struct mnt_idmap *, struct inode *, int);
> static inline int file_permission(struct file *file, int mask)
> {
> return inode_permission(file_mnt_idmap(file),
> @@ -3397,7 +3397,7 @@ static inline bool generic_ci_validate_strict_name(struct inode *dir,
> }
> #endif
>
> -int may_setattr(struct mnt_idmap *idmap, struct inode *inode,
> +int may_setattr(const struct mnt_idmap *idmap, struct inode *inode,
> unsigned int ia_valid);
> int setattr_prepare(struct mnt_idmap *, struct dentry *, struct iattr *);
> extern int inode_newsize_ok(const struct inode *, loff_t offset);
> diff --git a/include/linux/nfs_fs.h b/include/linux/nfs_fs.h
> index b85a73ae7919..b2828ea03abe 100644
> --- a/include/linux/nfs_fs.h
> +++ b/include/linux/nfs_fs.h
> @@ -441,7 +441,7 @@ extern int nfs_getattr(struct mnt_idmap *, const struct path *,
> struct kstat *, u32, unsigned int);
> extern void nfs_access_add_cache(struct inode *, struct nfs_access_entry *, const struct cred *);
> extern void nfs_access_set_mask(struct nfs_access_entry *, u32);
> -extern int nfs_permission(struct mnt_idmap *, struct inode *, int);
> +extern int nfs_permission(const struct mnt_idmap *, struct inode *, int);
> extern int nfs_open(struct inode *, struct file *);
> extern int nfs_attribute_cache_expired(struct inode *inode);
> extern int nfs_revalidate_inode(struct inode *inode, unsigned long flags);
> diff --git a/security/selinux/selinuxfs.c b/security/selinux/selinuxfs.c
> index c7d91476971c..a0be7f1b5993 100644
> --- a/security/selinux/selinuxfs.c
> +++ b/security/selinux/selinuxfs.c
> @@ -1782,7 +1782,7 @@ static struct dentry *sel_make_dir(struct dentry *dir, const char *name,
> return sel_attach(dir, name, inode);
> }
>
> -static int reject_all(struct mnt_idmap *idmap, struct inode *inode, int mask)
> +static int reject_all(const struct mnt_idmap *idmap, struct inode *inode, int mask)
> {
> return -EPERM; // no access for anyone, root or no root.
> }
>
> --
> 2.53.0
>
--
Jan Kara <jack@xxxxxxxx>
SUSE Labs, CR