Re: [PATCH 11/27] fs: port acl to const mnt_idmap

From: Jan Kara

Date: Wed Sep 02 2026 - 10:45:38 EST

On Tue 01-09-26 14:14:36, 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

> ---
> fs/ntfs/ea.c | 4 ++--
> fs/ntfs/ea.h | 2 +-
> fs/ntfs/namei.c | 2 +-
> fs/ntfs3/inode.c | 2 +-
> fs/ntfs3/ntfs_fs.h | 4 ++--
> fs/ntfs3/xattr.c | 4 ++--
> fs/posix_acl.c | 6 +++---
> include/linux/lsm_hook_defs.h | 8 ++++----
> include/linux/posix_acl.h | 4 ++--
> include/linux/security.h | 16 ++++++++--------
> security/integrity/evm/evm_main.c | 10 +++++-----
> security/integrity/ima/ima_appraise.c | 4 ++--
> security/security.c | 8 ++++----
> security/selinux/hooks.c | 6 +++---
> security/smack/smack_lsm.c | 6 +++---
> 15 files changed, 43 insertions(+), 43 deletions(-)
>
> diff --git a/fs/ntfs/ea.c b/fs/ntfs/ea.c
> index cdd306933d73..744ea8c446e5 100644
> --- a/fs/ntfs/ea.c
> +++ b/fs/ntfs/ea.c
> @@ -998,7 +998,7 @@ struct posix_acl *ntfs_get_acl(struct mnt_idmap *idmap, struct dentry *dentry,
> return acl;
> }
>
> -static noinline int ntfs_set_acl_ex(struct mnt_idmap *idmap,
> +static noinline int ntfs_set_acl_ex(const struct mnt_idmap *idmap,
> struct inode *inode, struct posix_acl *acl,
> int type, bool init_acl)
> {
> @@ -1086,7 +1086,7 @@ int ntfs_set_acl(struct mnt_idmap *idmap, struct dentry *dentry,
> return ntfs_set_acl_ex(idmap, d_inode(dentry), acl, type, false);
> }
>
> -int ntfs_init_acl(struct mnt_idmap *idmap, struct inode *inode,
> +int ntfs_init_acl(const struct mnt_idmap *idmap, struct inode *inode,
> struct inode *dir)
> {
> struct posix_acl *default_acl, *acl;
> diff --git a/fs/ntfs/ea.h b/fs/ntfs/ea.h
> index acb39c2a6fbc..9d17abc2e491 100644
> --- a/fs/ntfs/ea.h
> +++ b/fs/ntfs/ea.h
> @@ -21,7 +21,7 @@ struct posix_acl *ntfs_get_acl(struct mnt_idmap *idmap, struct dentry *dentry,
> int type);
> int ntfs_set_acl(struct mnt_idmap *idmap, struct dentry *dentry,
> struct posix_acl *acl, int type);
> -int ntfs_init_acl(struct mnt_idmap *idmap, struct inode *inode,
> +int ntfs_init_acl(const struct mnt_idmap *idmap, struct inode *inode,
> struct inode *dir);
> #else
> #define ntfs_get_acl NULL
> diff --git a/fs/ntfs/namei.c b/fs/ntfs/namei.c
> index 7091b2496fac..e2cf1ab6935a 100644
> --- a/fs/ntfs/namei.c
> +++ b/fs/ntfs/namei.c
> @@ -391,7 +391,7 @@ static int ntfs_sd_add_everyone(struct ntfs_inode *ni)
> return ret;
> }
>
> -static struct ntfs_inode *__ntfs_create(struct mnt_idmap *idmap, struct inode *dir,
> +static struct ntfs_inode *__ntfs_create(const struct mnt_idmap *idmap, struct inode *dir,
> __le16 *name, u8 name_len, mode_t mode, dev_t dev,
> const char *target, int target_len)
> {
> diff --git a/fs/ntfs3/inode.c b/fs/ntfs3/inode.c
> index 56b4f6469a28..a9fdd33f2886 100644
> --- a/fs/ntfs3/inode.c
> +++ b/fs/ntfs3/inode.c
> @@ -1381,7 +1381,7 @@ ntfs_create_reparse_buffer(struct ntfs_sb_info *sbi, const char *symname,
> *
> * NOTE: if fnd != NULL (ntfs_atomic_open) then @dir is locked
> */
> -int ntfs_create_inode(struct mnt_idmap *idmap, struct inode *dir,
> +int ntfs_create_inode(const struct mnt_idmap *idmap, struct inode *dir,
> struct dentry *dentry, const struct cpu_str *uni,
> umode_t mode, dev_t dev, const char *symname, u32 size,
> struct ntfs_fnd *fnd)
> diff --git a/fs/ntfs3/ntfs_fs.h b/fs/ntfs3/ntfs_fs.h
> index 5811d89d67b3..a2b74f41048f 100644
> --- a/fs/ntfs3/ntfs_fs.h
> +++ b/fs/ntfs3/ntfs_fs.h
> @@ -803,7 +803,7 @@ int ntfs_set_size(struct inode *inode, u64 new_size);
> int ntfs3_write_inode(struct inode *inode, struct writeback_control *wbc);
> int ntfs_sync_inode(struct inode *inode);
> int inode_read_data(struct inode *inode, void *data, size_t bytes);
> -int ntfs_create_inode(struct mnt_idmap *idmap, struct inode *dir,
> +int ntfs_create_inode(const struct mnt_idmap *idmap, struct inode *dir,
> struct dentry *dentry, const struct cpu_str *uni,
> umode_t mode, dev_t dev, const char *symname, u32 size,
> struct ntfs_fnd *fnd);
> @@ -967,7 +967,7 @@ struct posix_acl *ntfs_get_acl(struct mnt_idmap *idmap, struct dentry *dentry,
> int type);
> int ntfs_set_acl(struct mnt_idmap *idmap, struct dentry *dentry,
> struct posix_acl *acl, int type);
> -int ntfs_init_acl(struct mnt_idmap *idmap, struct inode *inode,
> +int ntfs_init_acl(const struct mnt_idmap *idmap, struct inode *inode,
> struct inode *dir);
> #else
> #define ntfs_get_acl NULL
> diff --git a/fs/ntfs3/xattr.c b/fs/ntfs3/xattr.c
> index 594ef6860b93..d800735477c3 100644
> --- a/fs/ntfs3/xattr.c
> +++ b/fs/ntfs3/xattr.c
> @@ -595,7 +595,7 @@ struct posix_acl *ntfs_get_acl(struct mnt_idmap *idmap, struct dentry *dentry,
> return acl;
> }
>
> -static noinline int ntfs_set_acl_ex(struct mnt_idmap *idmap,
> +static noinline int ntfs_set_acl_ex(const struct mnt_idmap *idmap,
> struct inode *inode, struct posix_acl *acl,
> int type, bool init_acl)
> {
> @@ -688,7 +688,7 @@ int ntfs_set_acl(struct mnt_idmap *idmap, struct dentry *dentry,
> *
> * Called from ntfs_create_inode().
> */
> -int ntfs_init_acl(struct mnt_idmap *idmap, struct inode *inode,
> +int ntfs_init_acl(const struct mnt_idmap *idmap, struct inode *inode,
> struct inode *dir)
> {
> struct posix_acl *default_acl, *acl;
> diff --git a/fs/posix_acl.c b/fs/posix_acl.c
> index f9c55a59c6c6..b279804ebf56 100644
> --- a/fs/posix_acl.c
> +++ b/fs/posix_acl.c
> @@ -378,7 +378,7 @@ EXPORT_SYMBOL(posix_acl_from_mode);
> * by the acl. Returns -E... otherwise.
> */
> int
> -posix_acl_permission(struct mnt_idmap *idmap, struct inode *inode,
> +posix_acl_permission(const struct mnt_idmap *idmap, struct inode *inode,
> const struct posix_acl *acl, int want)
> {
> const struct posix_acl_entry *pa, *pe, *mask_obj;
> @@ -709,7 +709,7 @@ EXPORT_SYMBOL_GPL(posix_acl_create);
> *
> * Called from set_acl inode operations.
> */
> -int posix_acl_update_mode(struct mnt_idmap *idmap,
> +int posix_acl_update_mode(const struct mnt_idmap *idmap,
> struct inode *inode, umode_t *mode_p,
> struct posix_acl **acl)
> {
> @@ -889,7 +889,7 @@ EXPORT_SYMBOL (posix_acl_to_xattr);
> * Return: On success, the size of the stored uapi posix acls, on error a
> * negative errno.
> */
> -static ssize_t vfs_posix_acl_to_xattr(struct mnt_idmap *idmap,
> +static ssize_t vfs_posix_acl_to_xattr(const struct mnt_idmap *idmap,
> struct inode *inode,
> const struct posix_acl *acl, void *buffer,
> size_t size)
> diff --git a/include/linux/lsm_hook_defs.h b/include/linux/lsm_hook_defs.h
> index 65c9609ec207..30897590258f 100644
> --- a/include/linux/lsm_hook_defs.h
> +++ b/include/linux/lsm_hook_defs.h
> @@ -159,15 +159,15 @@ LSM_HOOK(void, LSM_RET_VOID, inode_post_removexattr, struct dentry *dentry,
> const char *name)
> LSM_HOOK(int, 0, inode_file_setattr, struct dentry *dentry, struct file_kattr *fa)
> LSM_HOOK(int, 0, inode_file_getattr, struct dentry *dentry, struct file_kattr *fa)
> -LSM_HOOK(int, 0, inode_set_acl, struct mnt_idmap *idmap,
> +LSM_HOOK(int, 0, inode_set_acl, const struct mnt_idmap *idmap,
> struct dentry *dentry, const char *acl_name, struct posix_acl *kacl)
> LSM_HOOK(void, LSM_RET_VOID, inode_post_set_acl, struct dentry *dentry,
> const char *acl_name, struct posix_acl *kacl)
> -LSM_HOOK(int, 0, inode_get_acl, struct mnt_idmap *idmap,
> +LSM_HOOK(int, 0, inode_get_acl, const struct mnt_idmap *idmap,
> struct dentry *dentry, const char *acl_name)
> -LSM_HOOK(int, 0, inode_remove_acl, struct mnt_idmap *idmap,
> +LSM_HOOK(int, 0, inode_remove_acl, const struct mnt_idmap *idmap,
> struct dentry *dentry, const char *acl_name)
> -LSM_HOOK(void, LSM_RET_VOID, inode_post_remove_acl, struct mnt_idmap *idmap,
> +LSM_HOOK(void, LSM_RET_VOID, inode_post_remove_acl, const struct mnt_idmap *idmap,
> struct dentry *dentry, const char *acl_name)
> LSM_HOOK(int, 0, inode_need_killpriv, struct dentry *dentry)
> LSM_HOOK(int, 0, inode_killpriv, struct mnt_idmap *idmap,
> diff --git a/include/linux/posix_acl.h b/include/linux/posix_acl.h
> index 62d497763e25..7c6cfcae0a9d 100644
> --- a/include/linux/posix_acl.h
> +++ b/include/linux/posix_acl.h
> @@ -84,7 +84,7 @@ struct posix_acl *posix_acl_clone(const struct posix_acl *acl, gfp_t flags);
> int posix_acl_chmod(struct mnt_idmap *, struct dentry *, umode_t);
> extern int posix_acl_create(struct inode *, umode_t *, struct posix_acl **,
> struct posix_acl **);
> -int posix_acl_update_mode(struct mnt_idmap *, struct inode *, umode_t *,
> +int posix_acl_update_mode(const struct mnt_idmap *, struct inode *, umode_t *,
> struct posix_acl **);
>
> int simple_set_acl(struct mnt_idmap *, struct dentry *,
> @@ -96,7 +96,7 @@ void set_cached_acl(struct inode *inode, int type, struct posix_acl *acl);
> void forget_cached_acl(struct inode *inode, int type);
> void forget_all_cached_acls(struct inode *inode);
> int posix_acl_valid(struct user_namespace *, const struct posix_acl *);
> -int posix_acl_permission(struct mnt_idmap *, struct inode *,
> +int posix_acl_permission(const struct mnt_idmap *, struct inode *,
> const struct posix_acl *, int);
>
> static inline void cache_no_acl(struct inode *inode)
> diff --git a/include/linux/security.h b/include/linux/security.h
> index 4598a13657ee..12bc12e243bf 100644
> --- a/include/linux/security.h
> +++ b/include/linux/security.h
> @@ -430,16 +430,16 @@ int security_inode_getattr(const struct path *path);
> int security_inode_setxattr(struct mnt_idmap *idmap,
> struct dentry *dentry, const char *name,
> const void *value, size_t size, int flags);
> -int security_inode_set_acl(struct mnt_idmap *idmap,
> +int security_inode_set_acl(const struct mnt_idmap *idmap,
> struct dentry *dentry, const char *acl_name,
> struct posix_acl *kacl);
> void security_inode_post_set_acl(struct dentry *dentry, const char *acl_name,
> struct posix_acl *kacl);
> -int security_inode_get_acl(struct mnt_idmap *idmap,
> +int security_inode_get_acl(const struct mnt_idmap *idmap,
> struct dentry *dentry, const char *acl_name);
> -int security_inode_remove_acl(struct mnt_idmap *idmap,
> +int security_inode_remove_acl(const struct mnt_idmap *idmap,
> struct dentry *dentry, const char *acl_name);
> -void security_inode_post_remove_acl(struct mnt_idmap *idmap,
> +void security_inode_post_remove_acl(const struct mnt_idmap *idmap,
> struct dentry *dentry,
> const char *acl_name);
> void security_inode_post_setxattr(struct dentry *dentry, const char *name,
> @@ -1003,7 +1003,7 @@ static inline int security_inode_setxattr(struct mnt_idmap *idmap,
> return cap_inode_setxattr(dentry, name, value, size, flags);
> }
>
> -static inline int security_inode_set_acl(struct mnt_idmap *idmap,
> +static inline int security_inode_set_acl(const struct mnt_idmap *idmap,
> struct dentry *dentry,
> const char *acl_name,
> struct posix_acl *kacl)
> @@ -1016,21 +1016,21 @@ static inline void security_inode_post_set_acl(struct dentry *dentry,
> struct posix_acl *kacl)
> { }
>
> -static inline int security_inode_get_acl(struct mnt_idmap *idmap,
> +static inline int security_inode_get_acl(const struct mnt_idmap *idmap,
> struct dentry *dentry,
> const char *acl_name)
> {
> return 0;
> }
>
> -static inline int security_inode_remove_acl(struct mnt_idmap *idmap,
> +static inline int security_inode_remove_acl(const struct mnt_idmap *idmap,
> struct dentry *dentry,
> const char *acl_name)
> {
> return 0;
> }
>
> -static inline void security_inode_post_remove_acl(struct mnt_idmap *idmap,
> +static inline void security_inode_post_remove_acl(const struct mnt_idmap *idmap,
> struct dentry *dentry,
> const char *acl_name)
> { }
> diff --git a/security/integrity/evm/evm_main.c b/security/integrity/evm/evm_main.c
> index 06e187c9912d..aaf228ebed7c 100644
> --- a/security/integrity/evm/evm_main.c
> +++ b/security/integrity/evm/evm_main.c
> @@ -652,7 +652,7 @@ static int evm_inode_removexattr(struct mnt_idmap *idmap, struct dentry *dentry,
> }
>
> #ifdef CONFIG_FS_POSIX_ACL
> -static int evm_inode_set_acl_change(struct mnt_idmap *idmap,
> +static int evm_inode_set_acl_change(const struct mnt_idmap *idmap,
> struct dentry *dentry, const char *name,
> struct posix_acl *kacl)
> {
> @@ -671,7 +671,7 @@ static int evm_inode_set_acl_change(struct mnt_idmap *idmap,
> return 0;
> }
> #else
> -static inline int evm_inode_set_acl_change(struct mnt_idmap *idmap,
> +static inline int evm_inode_set_acl_change(const struct mnt_idmap *idmap,
> struct dentry *dentry,
> const char *name,
> struct posix_acl *kacl)
> @@ -693,7 +693,7 @@ static inline int evm_inode_set_acl_change(struct mnt_idmap *idmap,
> *
> * Return: zero on success, -EPERM on failure.
> */
> -static int evm_inode_set_acl(struct mnt_idmap *idmap, struct dentry *dentry,
> +static int evm_inode_set_acl(const struct mnt_idmap *idmap, struct dentry *dentry,
> const char *acl_name, struct posix_acl *kacl)
> {
> enum integrity_status evm_status;
> @@ -745,7 +745,7 @@ static int evm_inode_set_acl(struct mnt_idmap *idmap, struct dentry *dentry,
> *
> * Return: zero on success, -EPERM on failure.
> */
> -static int evm_inode_remove_acl(struct mnt_idmap *idmap, struct dentry *dentry,
> +static int evm_inode_remove_acl(const struct mnt_idmap *idmap, struct dentry *dentry,
> const char *acl_name)
> {
> return evm_inode_set_acl(idmap, dentry, acl_name, NULL);
> @@ -926,7 +926,7 @@ static void evm_inode_post_removexattr(struct dentry *dentry,
> * Update the 'security.evm' xattr with the EVM HMAC re-calculated after
> * removing posix acls.
> */
> -static inline void evm_inode_post_remove_acl(struct mnt_idmap *idmap,
> +static inline void evm_inode_post_remove_acl(const struct mnt_idmap *idmap,
> struct dentry *dentry,
> const char *acl_name)
> {
> diff --git a/security/integrity/ima/ima_appraise.c b/security/integrity/ima/ima_appraise.c
> index 6b21db789ef1..1aed041c127a 100644
> --- a/security/integrity/ima/ima_appraise.c
> +++ b/security/integrity/ima/ima_appraise.c
> @@ -790,7 +790,7 @@ static int ima_inode_setxattr(struct mnt_idmap *idmap, struct dentry *dentry,
> return result;
> }
>
> -static int ima_inode_set_acl(struct mnt_idmap *idmap, struct dentry *dentry,
> +static int ima_inode_set_acl(const struct mnt_idmap *idmap, struct dentry *dentry,
> const char *acl_name, struct posix_acl *kacl)
> {
> if (evm_revalidate_status(acl_name))
> @@ -815,7 +815,7 @@ static int ima_inode_removexattr(struct mnt_idmap *idmap, struct dentry *dentry,
> return result;
> }
>
> -static int ima_inode_remove_acl(struct mnt_idmap *idmap, struct dentry *dentry,
> +static int ima_inode_remove_acl(const struct mnt_idmap *idmap, struct dentry *dentry,
> const char *acl_name)
> {
> return ima_inode_set_acl(idmap, dentry, acl_name, NULL);
> diff --git a/security/security.c b/security/security.c
> index 2ee276ab15c5..e81dcda3050b 100644
> --- a/security/security.c
> +++ b/security/security.c
> @@ -1953,7 +1953,7 @@ int security_inode_setxattr(struct mnt_idmap *idmap,
> *
> * Return: Returns 0 if permission is granted.
> */
> -int security_inode_set_acl(struct mnt_idmap *idmap,
> +int security_inode_set_acl(const struct mnt_idmap *idmap,
> struct dentry *dentry, const char *acl_name,
> struct posix_acl *kacl)
> {
> @@ -1990,7 +1990,7 @@ void security_inode_post_set_acl(struct dentry *dentry, const char *acl_name,
> *
> * Return: Returns 0 if permission is granted.
> */
> -int security_inode_get_acl(struct mnt_idmap *idmap,
> +int security_inode_get_acl(const struct mnt_idmap *idmap,
> struct dentry *dentry, const char *acl_name)
> {
> if (unlikely(IS_PRIVATE(d_backing_inode(dentry))))
> @@ -2009,7 +2009,7 @@ int security_inode_get_acl(struct mnt_idmap *idmap,
> *
> * Return: Returns 0 if permission is granted.
> */
> -int security_inode_remove_acl(struct mnt_idmap *idmap,
> +int security_inode_remove_acl(const struct mnt_idmap *idmap,
> struct dentry *dentry, const char *acl_name)
> {
> if (unlikely(IS_PRIVATE(d_backing_inode(dentry))))
> @@ -2026,7 +2026,7 @@ int security_inode_remove_acl(struct mnt_idmap *idmap,
> * Update inode security data after successfully removing posix acls on
> * @dentry in @idmap. The posix acls are identified by @acl_name.
> */
> -void security_inode_post_remove_acl(struct mnt_idmap *idmap,
> +void security_inode_post_remove_acl(const struct mnt_idmap *idmap,
> struct dentry *dentry, const char *acl_name)
> {
> if (unlikely(IS_PRIVATE(d_backing_inode(dentry))))
> diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
> index 035aaf113d1d..672d6374d8b0 100644
> --- a/security/selinux/hooks.c
> +++ b/security/selinux/hooks.c
> @@ -3453,20 +3453,20 @@ static int selinux_inode_setxattr(struct mnt_idmap *idmap,
> &ad);
> }
>
> -static int selinux_inode_set_acl(struct mnt_idmap *idmap,
> +static int selinux_inode_set_acl(const struct mnt_idmap *idmap,
> struct dentry *dentry, const char *acl_name,
> struct posix_acl *kacl)
> {
> return dentry_has_perm(current_cred(), dentry, FILE__SETATTR);
> }
>
> -static int selinux_inode_get_acl(struct mnt_idmap *idmap,
> +static int selinux_inode_get_acl(const struct mnt_idmap *idmap,
> struct dentry *dentry, const char *acl_name)
> {
> return dentry_has_perm(current_cred(), dentry, FILE__GETATTR);
> }
>
> -static int selinux_inode_remove_acl(struct mnt_idmap *idmap,
> +static int selinux_inode_remove_acl(const struct mnt_idmap *idmap,
> struct dentry *dentry, const char *acl_name)
> {
> return dentry_has_perm(current_cred(), dentry, FILE__SETATTR);
> diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
> index 8e88ac65fd7f..244cdb49e928 100644
> --- a/security/smack/smack_lsm.c
> +++ b/security/smack/smack_lsm.c
> @@ -1543,7 +1543,7 @@ static int smack_inode_removexattr(struct mnt_idmap *idmap,
> *
> * Returns 0 if access is permitted, an error code otherwise
> */
> -static int smack_inode_set_acl(struct mnt_idmap *idmap,
> +static int smack_inode_set_acl(const struct mnt_idmap *idmap,
> struct dentry *dentry, const char *acl_name,
> struct posix_acl *kacl)
> {
> @@ -1566,7 +1566,7 @@ static int smack_inode_set_acl(struct mnt_idmap *idmap,
> *
> * Returns 0 if access is permitted, an error code otherwise
> */
> -static int smack_inode_get_acl(struct mnt_idmap *idmap,
> +static int smack_inode_get_acl(const struct mnt_idmap *idmap,
> struct dentry *dentry, const char *acl_name)
> {
> struct smk_audit_info ad;
> @@ -1588,7 +1588,7 @@ static int smack_inode_get_acl(struct mnt_idmap *idmap,
> *
> * Returns 0 if access is permitted, an error code otherwise
> */
> -static int smack_inode_remove_acl(struct mnt_idmap *idmap,
> +static int smack_inode_remove_acl(const struct mnt_idmap *idmap,
> struct dentry *dentry, const char *acl_name)
> {
> struct smk_audit_info ad;
>
> --
> 2.53.0
>
--
Jan Kara <jack@xxxxxxxx>
SUSE Labs, CR