[PATCHES] struct path constification

[PATCHES] struct path constification

[Al Viro]

	This is mostly whack-a-mole stuff - a bunch of places
are passing struct path pointers around, without bothering
to mark them const, even though they are not going to try
and modify the contents of struct path.

	It's a bad practice, since there are invariants along
the lines of "file->f_path stays unchanged open-to-release"
and verifying those can get very unpleasant when you are
forced to take detours down the long call chains that could've
been avoided.

	Patches in that pile are independent from each other
and if anyone wants to grab some of them into subsystem's
tree - just say so; I'll be happy to exclude those from the
vfs.git branch if they go into another tree.

	Currently they are in vfs.git#work.path; individual
patches in followups.

Subject: [PATCH 01/11] ->getprocattr(): attribute name is const char *, TYVM...

[Al Viro]

cast of ->d_name.name to char * is completely wrong - nothing is
allowed to modify its contents.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
 fs/proc/base.c                | 2 +-
 include/linux/lsm_hook_defs.h | 2 +-
 include/linux/security.h      | 4 ++--
 security/apparmor/lsm.c       | 2 +-
 security/security.c           | 4 ++--
 security/selinux/hooks.c      | 2 +-
 security/smack/smack_lsm.c    | 2 +-
 7 files changed, 9 insertions(+), 9 deletions(-)

diff --git a/fs/proc/base.c b/fs/proc/base.c
index 93f7e3d971e4..e347b8ce140c 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -2728,7 +2728,7 @@ static ssize_t proc_pid_attr_read(struct file * file, char __user * buf,
 		return -ESRCH;
 
 	length = security_getprocattr(task, PROC_I(inode)->op.lsm,
-				      (char*)file->f_path.dentry->d_name.name,
+				      file->f_path.dentry->d_name.name,
 				      &p);
 	put_task_struct(task);
 	if (length > 0)
diff --git a/include/linux/lsm_hook_defs.h b/include/linux/lsm_hook_defs.h
index 806448173033..03360d27bedf 100644
--- a/include/linux/lsm_hook_defs.h
+++ b/include/linux/lsm_hook_defs.h
@@ -253,7 +253,7 @@ LSM_HOOK(int, 0, sem_semop, struct kern_ipc_perm *perm, struct sembuf *sops,
 LSM_HOOK(int, 0, netlink_send, struct sock *sk, struct sk_buff *skb)
 LSM_HOOK(void, LSM_RET_VOID, d_instantiate, struct dentry *dentry,
 	 struct inode *inode)
-LSM_HOOK(int, -EINVAL, getprocattr, struct task_struct *p, char *name,
+LSM_HOOK(int, -EINVAL, getprocattr, struct task_struct *p, const char *name,
 	 char **value)
 LSM_HOOK(int, -EINVAL, setprocattr, const char *name, void *value, size_t size)
 LSM_HOOK(int, 0, ismaclabel, const char *name)
diff --git a/include/linux/security.h b/include/linux/security.h
index 1bc362cb413f..93488c01d9bd 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -461,7 +461,7 @@ int security_sem_semctl(struct kern_ipc_perm *sma, int cmd);
 int security_sem_semop(struct kern_ipc_perm *sma, struct sembuf *sops,
 			unsigned nsops, int alter);
 void security_d_instantiate(struct dentry *dentry, struct inode *inode);
-int security_getprocattr(struct task_struct *p, const char *lsm, char *name,
+int security_getprocattr(struct task_struct *p, const char *lsm, const char *name,
 			 char **value);
 int security_setprocattr(const char *lsm, const char *name, void *value,
 			 size_t size);
@@ -1301,7 +1301,7 @@ static inline void security_d_instantiate(struct dentry *dentry,
 { }
 
 static inline int security_getprocattr(struct task_struct *p, const char *lsm,
-				       char *name, char **value)
+				       const char *name, char **value)
 {
 	return -EINVAL;
 }
diff --git a/security/apparmor/lsm.c b/security/apparmor/lsm.c
index e29cade7b662..f56070270c69 100644
--- a/security/apparmor/lsm.c
+++ b/security/apparmor/lsm.c
@@ -614,7 +614,7 @@ static int apparmor_sb_pivotroot(const struct path *old_path,
 	return error;
 }
 
-static int apparmor_getprocattr(struct task_struct *task, char *name,
+static int apparmor_getprocattr(struct task_struct *task, const char *name,
 				char **value)
 {
 	int error = -ENOENT;
diff --git a/security/security.c b/security/security.c
index 14d30fec8a00..d8227531e2fd 100644
--- a/security/security.c
+++ b/security/security.c
@@ -2057,8 +2057,8 @@ void security_d_instantiate(struct dentry *dentry, struct inode *inode)
 }
 EXPORT_SYMBOL(security_d_instantiate);
 
-int security_getprocattr(struct task_struct *p, const char *lsm, char *name,
-				char **value)
+int security_getprocattr(struct task_struct *p, const char *lsm,
+			 const char *name, char **value)
 {
 	struct security_hook_list *hp;
 
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 79573504783b..c8168d19fb96 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -6327,7 +6327,7 @@ static void selinux_d_instantiate(struct dentry *dentry, struct inode *inode)
 }
 
 static int selinux_getprocattr(struct task_struct *p,
-			       char *name, char **value)
+			       const char *name, char **value)
 {
 	const struct task_security_struct *__tsec;
 	u32 sid;
diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
index 001831458fa2..434b348d8fcd 100644
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -3479,7 +3479,7 @@ static void smack_d_instantiate(struct dentry *opt_dentry, struct inode *inode)
  *
  * Returns the length of the smack label or an error code
  */
-static int smack_getprocattr(struct task_struct *p, char *name, char **value)
+static int smack_getprocattr(struct task_struct *p, const char *name, char **value)
 {
 	struct smack_known *skp = smk_of_task_struct_obj(p);
 	char *cp;
-- 
2.30.2

Re: Subject: [PATCH 01/11] ->getprocattr(): attribute name is const char *, TYVM...

[Paul Moore]

On Sat, Aug 20, 2022 at 2:12 PM Al Viro <viro@zeniv.linux.org.uk> wrote:
>
> cast of ->d_name.name to char * is completely wrong - nothing is
> allowed to modify its contents.
>
> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
> ---
>  fs/proc/base.c                | 2 +-
>  include/linux/lsm_hook_defs.h | 2 +-
>  include/linux/security.h      | 4 ++--
>  security/apparmor/lsm.c       | 2 +-
>  security/security.c           | 4 ++--
>  security/selinux/hooks.c      | 2 +-
>  security/smack/smack_lsm.c    | 2 +-
>  7 files changed, 9 insertions(+), 9 deletions(-)

Thanks Al.  Based on your other email it sounds like you are going to
send these up to Linus, which is fine by me, but if that changes let
me know and I'll make sure this patch gets sent up.

Acked-by: Paul Moore <paul@paul-moore.com>

-- 
paul-moore.com

Re: Subject: [PATCH 01/11] ->getprocattr(): attribute name is const char *, TYVM...

[Casey Schaufler]

On 8/20/2022 11:11 AM, Al Viro wrote:
> cast of ->d_name.name to char * is completely wrong - nothing is
> allowed to modify its contents.
>
> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

Acked-by: Casey Schaufler <casey@schaufler-ca.com>

Thank you for the fix. Please feel free to submit this
directly.

> ---
>  fs/proc/base.c                | 2 +-
>  include/linux/lsm_hook_defs.h | 2 +-
>  include/linux/security.h      | 4 ++--
>  security/apparmor/lsm.c       | 2 +-
>  security/security.c           | 4 ++--
>  security/selinux/hooks.c      | 2 +-
>  security/smack/smack_lsm.c    | 2 +-
>  7 files changed, 9 insertions(+), 9 deletions(-)
>
> diff --git a/fs/proc/base.c b/fs/proc/base.c
> index 93f7e3d971e4..e347b8ce140c 100644
> --- a/fs/proc/base.c
> +++ b/fs/proc/base.c
> @@ -2728,7 +2728,7 @@ static ssize_t proc_pid_attr_read(struct file * file, char __user * buf,
>  		return -ESRCH;
>  
>  	length = security_getprocattr(task, PROC_I(inode)->op.lsm,
> -				      (char*)file->f_path.dentry->d_name.name,
> +				      file->f_path.dentry->d_name.name,
>  				      &p);
>  	put_task_struct(task);
>  	if (length > 0)
> diff --git a/include/linux/lsm_hook_defs.h b/include/linux/lsm_hook_defs.h
> index 806448173033..03360d27bedf 100644
> --- a/include/linux/lsm_hook_defs.h
> +++ b/include/linux/lsm_hook_defs.h
> @@ -253,7 +253,7 @@ LSM_HOOK(int, 0, sem_semop, struct kern_ipc_perm *perm, struct sembuf *sops,
>  LSM_HOOK(int, 0, netlink_send, struct sock *sk, struct sk_buff *skb)
>  LSM_HOOK(void, LSM_RET_VOID, d_instantiate, struct dentry *dentry,
>  	 struct inode *inode)
> -LSM_HOOK(int, -EINVAL, getprocattr, struct task_struct *p, char *name,
> +LSM_HOOK(int, -EINVAL, getprocattr, struct task_struct *p, const char *name,
>  	 char **value)
>  LSM_HOOK(int, -EINVAL, setprocattr, const char *name, void *value, size_t size)
>  LSM_HOOK(int, 0, ismaclabel, const char *name)
> diff --git a/include/linux/security.h b/include/linux/security.h
> index 1bc362cb413f..93488c01d9bd 100644
> --- a/include/linux/security.h
> +++ b/include/linux/security.h
> @@ -461,7 +461,7 @@ int security_sem_semctl(struct kern_ipc_perm *sma, int cmd);
>  int security_sem_semop(struct kern_ipc_perm *sma, struct sembuf *sops,
>  			unsigned nsops, int alter);
>  void security_d_instantiate(struct dentry *dentry, struct inode *inode);
> -int security_getprocattr(struct task_struct *p, const char *lsm, char *name,
> +int security_getprocattr(struct task_struct *p, const char *lsm, const char *name,
>  			 char **value);
>  int security_setprocattr(const char *lsm, const char *name, void *value,
>  			 size_t size);
> @@ -1301,7 +1301,7 @@ static inline void security_d_instantiate(struct dentry *dentry,
>  { }
>  
>  static inline int security_getprocattr(struct task_struct *p, const char *lsm,
> -				       char *name, char **value)
> +				       const char *name, char **value)
>  {
>  	return -EINVAL;
>  }
> diff --git a/security/apparmor/lsm.c b/security/apparmor/lsm.c
> index e29cade7b662..f56070270c69 100644
> --- a/security/apparmor/lsm.c
> +++ b/security/apparmor/lsm.c
> @@ -614,7 +614,7 @@ static int apparmor_sb_pivotroot(const struct path *old_path,
>  	return error;
>  }
>  
> -static int apparmor_getprocattr(struct task_struct *task, char *name,
> +static int apparmor_getprocattr(struct task_struct *task, const char *name,
>  				char **value)
>  {
>  	int error = -ENOENT;
> diff --git a/security/security.c b/security/security.c
> index 14d30fec8a00..d8227531e2fd 100644
> --- a/security/security.c
> +++ b/security/security.c
> @@ -2057,8 +2057,8 @@ void security_d_instantiate(struct dentry *dentry, struct inode *inode)
>  }
>  EXPORT_SYMBOL(security_d_instantiate);
>  
> -int security_getprocattr(struct task_struct *p, const char *lsm, char *name,
> -				char **value)
> +int security_getprocattr(struct task_struct *p, const char *lsm,
> +			 const char *name, char **value)
>  {
>  	struct security_hook_list *hp;
>  
> diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
> index 79573504783b..c8168d19fb96 100644
> --- a/security/selinux/hooks.c
> +++ b/security/selinux/hooks.c
> @@ -6327,7 +6327,7 @@ static void selinux_d_instantiate(struct dentry *dentry, struct inode *inode)
>  }
>  
>  static int selinux_getprocattr(struct task_struct *p,
> -			       char *name, char **value)
> +			       const char *name, char **value)
>  {
>  	const struct task_security_struct *__tsec;
>  	u32 sid;
> diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
> index 001831458fa2..434b348d8fcd 100644
> --- a/security/smack/smack_lsm.c
> +++ b/security/smack/smack_lsm.c
> @@ -3479,7 +3479,7 @@ static void smack_d_instantiate(struct dentry *opt_dentry, struct inode *inode)
>   *
>   * Returns the length of the smack label or an error code
>   */
> -static int smack_getprocattr(struct task_struct *p, char *name, char **value)
> +static int smack_getprocattr(struct task_struct *p, const char *name, char **value)
>  {
>  	struct smack_known *skp = smk_of_task_struct_obj(p);
>  	char *cp;

[PATCH 02/11] do_sys_name_to_handle(): constify path

[Al Viro]

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
 fs/fhandle.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/fhandle.c b/fs/fhandle.c
index 6630c69c23a2..f2bc27d1975e 100644
--- a/fs/fhandle.c
+++ b/fs/fhandle.c
@@ -14,7 +14,7 @@
 #include "internal.h"
 #include "mount.h"
 
-static long do_sys_name_to_handle(struct path *path,
+static long do_sys_name_to_handle(const struct path *path,
 				  struct file_handle __user *ufh,
 				  int __user *mnt_id)
 {
-- 
2.30.2

[PATCH 03/11] may_linkat(): constify path

[Al Viro]

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
 fs/internal.h | 2 +-
 fs/namei.c    | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/fs/internal.h b/fs/internal.h
index 87e96b9024ce..c209b4838d68 100644
--- a/fs/internal.h
+++ b/fs/internal.h
@@ -62,7 +62,7 @@ extern int vfs_path_lookup(struct dentry *, struct vfsmount *,
 			   const char *, unsigned int, struct path *);
 int do_rmdir(int dfd, struct filename *name);
 int do_unlinkat(int dfd, struct filename *name);
-int may_linkat(struct user_namespace *mnt_userns, struct path *link);
+int may_linkat(struct user_namespace *mnt_userns, const struct path *link);
 int do_renameat2(int olddfd, struct filename *oldname, int newdfd,
 		 struct filename *newname, unsigned int flags);
 int do_mkdirat(int dfd, struct filename *name, umode_t mode);
diff --git a/fs/namei.c b/fs/namei.c
index 53b4bc094db2..6a5ab1a6f01b 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -1178,7 +1178,7 @@ static bool safe_hardlink_source(struct user_namespace *mnt_userns,
  *
  * Returns 0 if successful, -ve on error.
  */
-int may_linkat(struct user_namespace *mnt_userns, struct path *link)
+int may_linkat(struct user_namespace *mnt_userns, const struct path *link)
 {
 	struct inode *inode = link->dentry->d_inode;
 
-- 
2.30.2

[PATCH 04/11] fs/notify: constify path

[Al Viro]

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
 fs/notify/fanotify/fanotify.c      | 2 +-
 fs/notify/fanotify/fanotify.h      | 2 +-
 fs/notify/fanotify/fanotify_user.c | 6 +++---
 3 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/fs/notify/fanotify/fanotify.c b/fs/notify/fanotify/fanotify.c
index cd7d09a569ff..a2a15bc4df28 100644
--- a/fs/notify/fanotify/fanotify.c
+++ b/fs/notify/fanotify/fanotify.c
@@ -18,7 +18,7 @@
 
 #include "fanotify.h"
 
-static bool fanotify_path_equal(struct path *p1, struct path *p2)
+static bool fanotify_path_equal(const struct path *p1, const struct path *p2)
 {
 	return p1->mnt == p2->mnt && p1->dentry == p2->dentry;
 }
diff --git a/fs/notify/fanotify/fanotify.h b/fs/notify/fanotify/fanotify.h
index 1d9f11255c64..bf6d4d38afa0 100644
--- a/fs/notify/fanotify/fanotify.h
+++ b/fs/notify/fanotify/fanotify.h
@@ -458,7 +458,7 @@ static inline bool fanotify_event_has_path(struct fanotify_event *event)
 		event->type == FANOTIFY_EVENT_TYPE_PATH_PERM;
 }
 
-static inline struct path *fanotify_event_path(struct fanotify_event *event)
+static inline const struct path *fanotify_event_path(struct fanotify_event *event)
 {
 	if (event->type == FANOTIFY_EVENT_TYPE_PATH)
 		return &FANOTIFY_PE(event)->path;
diff --git a/fs/notify/fanotify/fanotify_user.c b/fs/notify/fanotify/fanotify_user.c
index f0e49a406ffa..4546da4a54f9 100644
--- a/fs/notify/fanotify/fanotify_user.c
+++ b/fs/notify/fanotify/fanotify_user.c
@@ -249,7 +249,7 @@ static struct fanotify_event *get_one_event(struct fsnotify_group *group,
 	return event;
 }
 
-static int create_fd(struct fsnotify_group *group, struct path *path,
+static int create_fd(struct fsnotify_group *group, const struct path *path,
 		     struct file **file)
 {
 	int client_fd;
@@ -619,7 +619,7 @@ static ssize_t copy_event_to_user(struct fsnotify_group *group,
 				  char __user *buf, size_t count)
 {
 	struct fanotify_event_metadata metadata;
-	struct path *path = fanotify_event_path(event);
+	const struct path *path = fanotify_event_path(event);
 	struct fanotify_info *info = fanotify_event_info(event);
 	unsigned int info_mode = FAN_GROUP_FLAG(group, FANOTIFY_INFO_MODES);
 	unsigned int pidfd_mode = info_mode & FAN_REPORT_PIDFD;
@@ -1553,7 +1553,7 @@ static int fanotify_test_fid(struct dentry *dentry)
 }
 
 static int fanotify_events_supported(struct fsnotify_group *group,
-				     struct path *path, __u64 mask,
+				     const struct path *path, __u64 mask,
 				     unsigned int flags)
 {
 	unsigned int mark_type = flags & FANOTIFY_MARK_TYPE_BITS;
-- 
2.30.2

Re: [PATCH 04/11] fs/notify: constify path

[Matthew Bobrowski]

On Sat, Aug 20, 2022 at 07:12:49PM +0100, Al Viro wrote:
> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

LGTM. Feel free to add:

Reviewed-by: Matthew Bobrowski <repnop@google.com>

> ---
>  fs/notify/fanotify/fanotify.c      | 2 +-
>  fs/notify/fanotify/fanotify.h      | 2 +-
>  fs/notify/fanotify/fanotify_user.c | 6 +++---
>  3 files changed, 5 insertions(+), 5 deletions(-)
> 
> diff --git a/fs/notify/fanotify/fanotify.c b/fs/notify/fanotify/fanotify.c
> index cd7d09a569ff..a2a15bc4df28 100644
> --- a/fs/notify/fanotify/fanotify.c
> +++ b/fs/notify/fanotify/fanotify.c
> @@ -18,7 +18,7 @@
>  
>  #include "fanotify.h"
>  
> -static bool fanotify_path_equal(struct path *p1, struct path *p2)
> +static bool fanotify_path_equal(const struct path *p1, const struct path *p2)
>  {
>  	return p1->mnt == p2->mnt && p1->dentry == p2->dentry;
>  }
> diff --git a/fs/notify/fanotify/fanotify.h b/fs/notify/fanotify/fanotify.h
> index 1d9f11255c64..bf6d4d38afa0 100644
> --- a/fs/notify/fanotify/fanotify.h
> +++ b/fs/notify/fanotify/fanotify.h
> @@ -458,7 +458,7 @@ static inline bool fanotify_event_has_path(struct fanotify_event *event)
>  		event->type == FANOTIFY_EVENT_TYPE_PATH_PERM;
>  }
>  
> -static inline struct path *fanotify_event_path(struct fanotify_event *event)
> +static inline const struct path *fanotify_event_path(struct fanotify_event *event)
>  {
>  	if (event->type == FANOTIFY_EVENT_TYPE_PATH)
>  		return &FANOTIFY_PE(event)->path;
> diff --git a/fs/notify/fanotify/fanotify_user.c b/fs/notify/fanotify/fanotify_user.c
> index f0e49a406ffa..4546da4a54f9 100644
> --- a/fs/notify/fanotify/fanotify_user.c
> +++ b/fs/notify/fanotify/fanotify_user.c
> @@ -249,7 +249,7 @@ static struct fanotify_event *get_one_event(struct fsnotify_group *group,
>  	return event;
>  }
>  
> -static int create_fd(struct fsnotify_group *group, struct path *path,
> +static int create_fd(struct fsnotify_group *group, const struct path *path,
>  		     struct file **file)
>  {
>  	int client_fd;
> @@ -619,7 +619,7 @@ static ssize_t copy_event_to_user(struct fsnotify_group *group,
>  				  char __user *buf, size_t count)
>  {
>  	struct fanotify_event_metadata metadata;
> -	struct path *path = fanotify_event_path(event);
> +	const struct path *path = fanotify_event_path(event);
>  	struct fanotify_info *info = fanotify_event_info(event);
>  	unsigned int info_mode = FAN_GROUP_FLAG(group, FANOTIFY_INFO_MODES);
>  	unsigned int pidfd_mode = info_mode & FAN_REPORT_PIDFD;
> @@ -1553,7 +1553,7 @@ static int fanotify_test_fid(struct dentry *dentry)
>  }
>  
>  static int fanotify_events_supported(struct fsnotify_group *group,
> -				     struct path *path, __u64 mask,
> +				     const struct path *path, __u64 mask,
>  				     unsigned int flags)
>  {
>  	unsigned int mark_type = flags & FANOTIFY_MARK_TYPE_BITS;
> -- 
> 2.30.2

/M

[PATCH 05/11] overlayfs: constify path

[Al Viro]

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
 fs/overlayfs/copy_up.c   | 12 ++++++------
 fs/overlayfs/file.c      |  2 +-
 fs/overlayfs/inode.c     |  6 +++---
 fs/overlayfs/namei.c     |  4 ++--
 fs/overlayfs/overlayfs.h | 22 +++++++++++-----------
 fs/overlayfs/readdir.c   | 16 ++++++++--------
 fs/overlayfs/super.c     |  8 ++++----
 fs/overlayfs/util.c      | 10 +++++-----
 8 files changed, 40 insertions(+), 40 deletions(-)

diff --git a/fs/overlayfs/copy_up.c b/fs/overlayfs/copy_up.c
index fdde6c56cc3d..3ffea291c410 100644
--- a/fs/overlayfs/copy_up.c
+++ b/fs/overlayfs/copy_up.c
@@ -44,7 +44,7 @@ static bool ovl_must_copy_xattr(const char *name)
 	       !strncmp(name, XATTR_SECURITY_PREFIX, XATTR_SECURITY_PREFIX_LEN);
 }
 
-int ovl_copy_xattr(struct super_block *sb, struct path *oldpath, struct dentry *new)
+int ovl_copy_xattr(struct super_block *sb, const struct path *oldpath, struct dentry *new)
 {
 	struct dentry *old = oldpath->dentry;
 	ssize_t list_size, size, value_size = 0;
@@ -132,8 +132,8 @@ int ovl_copy_xattr(struct super_block *sb, struct path *oldpath, struct dentry *
 	return error;
 }
 
-static int ovl_copy_fileattr(struct inode *inode, struct path *old,
-			     struct path *new)
+static int ovl_copy_fileattr(struct inode *inode, const struct path *old,
+			     const struct path *new)
 {
 	struct fileattr oldfa = { .flags_valid = true };
 	struct fileattr newfa = { .flags_valid = true };
@@ -193,8 +193,8 @@ static int ovl_copy_fileattr(struct inode *inode, struct path *old,
 	return ovl_real_fileattr_set(new, &newfa);
 }
 
-static int ovl_copy_up_data(struct ovl_fs *ofs, struct path *old,
-			    struct path *new, loff_t len)
+static int ovl_copy_up_data(struct ovl_fs *ofs, const struct path *old,
+			    const struct path *new, loff_t len)
 {
 	struct file *old_file;
 	struct file *new_file;
@@ -872,7 +872,7 @@ static bool ovl_need_meta_copy_up(struct dentry *dentry, umode_t mode,
 	return true;
 }
 
-static ssize_t ovl_getxattr_value(struct path *path, char *name, char **value)
+static ssize_t ovl_getxattr_value(const struct path *path, char *name, char **value)
 {
 	ssize_t res;
 	char *buf;
diff --git a/fs/overlayfs/file.c b/fs/overlayfs/file.c
index daff601b5c41..a1a22f58ba18 100644
--- a/fs/overlayfs/file.c
+++ b/fs/overlayfs/file.c
@@ -38,7 +38,7 @@ static char ovl_whatisit(struct inode *inode, struct inode *realinode)
 #define OVL_OPEN_FLAGS (O_NOATIME | FMODE_NONOTIFY)
 
 static struct file *ovl_open_realfile(const struct file *file,
-				      struct path *realpath)
+				      const struct path *realpath)
 {
 	struct inode *realinode = d_inode(realpath->dentry);
 	struct inode *inode = file_inode(file);
diff --git a/fs/overlayfs/inode.c b/fs/overlayfs/inode.c
index b45fea69fff3..19bd9af8b8a8 100644
--- a/fs/overlayfs/inode.c
+++ b/fs/overlayfs/inode.c
@@ -585,7 +585,7 @@ static int ovl_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
  * Introducing security_inode_fileattr_get/set() hooks would solve this issue
  * properly.
  */
-static int ovl_security_fileattr(struct path *realpath, struct fileattr *fa,
+static int ovl_security_fileattr(const struct path *realpath, struct fileattr *fa,
 				 bool set)
 {
 	struct file *file;
@@ -607,7 +607,7 @@ static int ovl_security_fileattr(struct path *realpath, struct fileattr *fa,
 	return err;
 }
 
-int ovl_real_fileattr_set(struct path *realpath, struct fileattr *fa)
+int ovl_real_fileattr_set(const struct path *realpath, struct fileattr *fa)
 {
 	int err;
 
@@ -682,7 +682,7 @@ static void ovl_fileattr_prot_flags(struct inode *inode, struct fileattr *fa)
 	}
 }
 
-int ovl_real_fileattr_get(struct path *realpath, struct fileattr *fa)
+int ovl_real_fileattr_get(const struct path *realpath, struct fileattr *fa)
 {
 	int err;
 
diff --git a/fs/overlayfs/namei.c b/fs/overlayfs/namei.c
index 69dc577974f8..0fd1d5fdfc72 100644
--- a/fs/overlayfs/namei.c
+++ b/fs/overlayfs/namei.c
@@ -26,7 +26,7 @@ struct ovl_lookup_data {
 	bool metacopy;
 };
 
-static int ovl_check_redirect(struct path *path, struct ovl_lookup_data *d,
+static int ovl_check_redirect(const struct path *path, struct ovl_lookup_data *d,
 			      size_t prelen, const char *post)
 {
 	int res;
@@ -194,7 +194,7 @@ struct dentry *ovl_decode_real_fh(struct ovl_fs *ofs, struct ovl_fh *fh,
 	return real;
 }
 
-static bool ovl_is_opaquedir(struct ovl_fs *ofs, struct path *path)
+static bool ovl_is_opaquedir(struct ovl_fs *ofs, const struct path *path)
 {
 	return ovl_path_check_dir_xattr(ofs, path, OVL_XATTR_OPAQUE);
 }
diff --git a/fs/overlayfs/overlayfs.h b/fs/overlayfs/overlayfs.h
index 87759165d32b..1ac96eaeda54 100644
--- a/fs/overlayfs/overlayfs.h
+++ b/fs/overlayfs/overlayfs.h
@@ -208,7 +208,7 @@ static inline int ovl_do_symlink(struct ovl_fs *ofs,
 	return err;
 }
 
-static inline ssize_t ovl_do_getxattr(struct path *path, const char *name,
+static inline ssize_t ovl_do_getxattr(const struct path *path, const char *name,
 				      void *value, size_t size)
 {
 	int err, len;
@@ -238,7 +238,7 @@ static inline ssize_t ovl_getxattr_upper(struct ovl_fs *ofs,
 }
 
 static inline ssize_t ovl_path_getxattr(struct ovl_fs *ofs,
-					 struct path *path,
+					 const struct path *path,
 					 enum ovl_xattr ox, void *value,
 					 size_t size)
 {
@@ -401,13 +401,13 @@ void ovl_inode_update(struct inode *inode, struct dentry *upperdentry);
 void ovl_dir_modified(struct dentry *dentry, bool impurity);
 u64 ovl_dentry_version_get(struct dentry *dentry);
 bool ovl_is_whiteout(struct dentry *dentry);
-struct file *ovl_path_open(struct path *path, int flags);
+struct file *ovl_path_open(const struct path *path, int flags);
 int ovl_copy_up_start(struct dentry *dentry, int flags);
 void ovl_copy_up_end(struct dentry *dentry);
 bool ovl_already_copied_up(struct dentry *dentry, int flags);
-bool ovl_path_check_dir_xattr(struct ovl_fs *ofs, struct path *path,
+bool ovl_path_check_dir_xattr(struct ovl_fs *ofs, const struct path *path,
 			      enum ovl_xattr ox);
-bool ovl_path_check_origin_xattr(struct ovl_fs *ofs, struct path *path);
+bool ovl_path_check_origin_xattr(struct ovl_fs *ofs, const struct path *path);
 
 static inline bool ovl_check_origin_xattr(struct ovl_fs *ofs,
 					  struct dentry *upperdentry)
@@ -430,9 +430,9 @@ bool ovl_need_index(struct dentry *dentry);
 int ovl_nlink_start(struct dentry *dentry);
 void ovl_nlink_end(struct dentry *dentry);
 int ovl_lock_rename_workdir(struct dentry *workdir, struct dentry *upperdir);
-int ovl_check_metacopy_xattr(struct ovl_fs *ofs, struct path *path);
+int ovl_check_metacopy_xattr(struct ovl_fs *ofs, const struct path *path);
 bool ovl_is_metacopy_dentry(struct dentry *dentry);
-char *ovl_get_redirect_xattr(struct ovl_fs *ofs, struct path *path, int padding);
+char *ovl_get_redirect_xattr(struct ovl_fs *ofs, const struct path *path, int padding);
 int ovl_sync_status(struct ovl_fs *ofs);
 
 static inline void ovl_set_flag(unsigned long flag, struct inode *inode)
@@ -556,7 +556,7 @@ void ovl_cleanup_whiteouts(struct ovl_fs *ofs, struct dentry *upper,
 			   struct list_head *list);
 void ovl_cache_free(struct list_head *list);
 void ovl_dir_cache_free(struct inode *inode);
-int ovl_check_d_type_supported(struct path *realpath);
+int ovl_check_d_type_supported(const struct path *realpath);
 int ovl_workdir_cleanup(struct ovl_fs *ofs, struct inode *dir,
 			struct vfsmount *mnt, struct dentry *dentry, int level);
 int ovl_indexdir_cleanup(struct ovl_fs *ofs);
@@ -673,8 +673,8 @@ struct dentry *ovl_create_temp(struct ovl_fs *ofs, struct dentry *workdir,
 extern const struct file_operations ovl_file_operations;
 int __init ovl_aio_request_cache_init(void);
 void ovl_aio_request_cache_destroy(void);
-int ovl_real_fileattr_get(struct path *realpath, struct fileattr *fa);
-int ovl_real_fileattr_set(struct path *realpath, struct fileattr *fa);
+int ovl_real_fileattr_get(const struct path *realpath, struct fileattr *fa);
+int ovl_real_fileattr_set(const struct path *realpath, struct fileattr *fa);
 int ovl_fileattr_get(struct dentry *dentry, struct fileattr *fa);
 int ovl_fileattr_set(struct user_namespace *mnt_userns,
 		     struct dentry *dentry, struct fileattr *fa);
@@ -683,7 +683,7 @@ int ovl_fileattr_set(struct user_namespace *mnt_userns,
 int ovl_copy_up(struct dentry *dentry);
 int ovl_copy_up_with_data(struct dentry *dentry);
 int ovl_maybe_copy_up(struct dentry *dentry, int flags);
-int ovl_copy_xattr(struct super_block *sb, struct path *path, struct dentry *new);
+int ovl_copy_xattr(struct super_block *sb, const struct path *path, struct dentry *new);
 int ovl_set_attr(struct ovl_fs *ofs, struct dentry *upper, struct kstat *stat);
 struct ovl_fh *ovl_encode_real_fh(struct ovl_fs *ofs, struct dentry *real,
 				  bool is_upper);
diff --git a/fs/overlayfs/readdir.c b/fs/overlayfs/readdir.c
index 78f62cc1797b..268ed415577a 100644
--- a/fs/overlayfs/readdir.c
+++ b/fs/overlayfs/readdir.c
@@ -264,7 +264,7 @@ static int ovl_fill_merge(struct dir_context *ctx, const char *name,
 		return ovl_fill_lowest(rdd, name, namelen, offset, ino, d_type);
 }
 
-static int ovl_check_whiteouts(struct path *path, struct ovl_readdir_data *rdd)
+static int ovl_check_whiteouts(const struct path *path, struct ovl_readdir_data *rdd)
 {
 	int err;
 	struct ovl_cache_entry *p;
@@ -291,7 +291,7 @@ static int ovl_check_whiteouts(struct path *path, struct ovl_readdir_data *rdd)
 	return err;
 }
 
-static inline int ovl_dir_read(struct path *realpath,
+static inline int ovl_dir_read(const struct path *realpath,
 			       struct ovl_readdir_data *rdd)
 {
 	struct file *realfile;
@@ -455,7 +455,7 @@ static u64 ovl_remap_lower_ino(u64 ino, int xinobits, int fsid,
  * copy up origin, call vfs_getattr() on the overlay entry to make
  * sure that d_ino will be consistent with st_ino from stat(2).
  */
-static int ovl_cache_update_ino(struct path *path, struct ovl_cache_entry *p)
+static int ovl_cache_update_ino(const struct path *path, struct ovl_cache_entry *p)
 
 {
 	struct dentry *dir = path->dentry;
@@ -547,7 +547,7 @@ static int ovl_fill_plain(struct dir_context *ctx, const char *name,
 	return 0;
 }
 
-static int ovl_dir_read_impure(struct path *path,  struct list_head *list,
+static int ovl_dir_read_impure(const struct path *path,  struct list_head *list,
 			       struct rb_root *root)
 {
 	int err;
@@ -592,7 +592,7 @@ static int ovl_dir_read_impure(struct path *path,  struct list_head *list,
 	return 0;
 }
 
-static struct ovl_dir_cache *ovl_cache_get_impure(struct path *path)
+static struct ovl_dir_cache *ovl_cache_get_impure(const struct path *path)
 {
 	int res;
 	struct dentry *dentry = path->dentry;
@@ -834,7 +834,7 @@ static loff_t ovl_dir_llseek(struct file *file, loff_t offset, int origin)
 }
 
 static struct file *ovl_dir_open_realfile(const struct file *file,
-					  struct path *realpath)
+					  const struct path *realpath)
 {
 	struct file *res;
 	const struct cred *old_cred;
@@ -1048,7 +1048,7 @@ static int ovl_check_d_type(struct dir_context *ctx, const char *name,
  * Returns 1 if d_type is supported, 0 not supported/unknown. Negative values
  * if error is encountered.
  */
-int ovl_check_d_type_supported(struct path *realpath)
+int ovl_check_d_type_supported(const struct path *realpath)
 {
 	int err;
 	struct ovl_readdir_data rdd = {
@@ -1065,7 +1065,7 @@ int ovl_check_d_type_supported(struct path *realpath)
 
 #define OVL_INCOMPATDIR_NAME "incompat"
 
-static int ovl_workdir_cleanup_recurse(struct ovl_fs *ofs, struct path *path,
+static int ovl_workdir_cleanup_recurse(struct ovl_fs *ofs, const struct path *path,
 				       int level)
 {
 	int err;
diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c
index ec746d447f1b..d51a02d555e0 100644
--- a/fs/overlayfs/super.c
+++ b/fs/overlayfs/super.c
@@ -908,7 +908,7 @@ static int ovl_mount_dir(const char *name, struct path *path)
 	return err;
 }
 
-static int ovl_check_namelen(struct path *path, struct ovl_fs *ofs,
+static int ovl_check_namelen(const struct path *path, struct ovl_fs *ofs,
 			     const char *name)
 {
 	struct kstatfs statfs;
@@ -1353,7 +1353,7 @@ static int ovl_create_volatile_dirty(struct ovl_fs *ofs)
 }
 
 static int ovl_make_workdir(struct super_block *sb, struct ovl_fs *ofs,
-			    struct path *workpath)
+			    const struct path *workpath)
 {
 	struct vfsmount *mnt = ovl_upper_mnt(ofs);
 	struct dentry *temp, *workdir;
@@ -1482,7 +1482,7 @@ static int ovl_make_workdir(struct super_block *sb, struct ovl_fs *ofs,
 }
 
 static int ovl_get_workdir(struct super_block *sb, struct ovl_fs *ofs,
-			   struct path *upperpath)
+			   const struct path *upperpath)
 {
 	int err;
 	struct path workpath = { };
@@ -1525,7 +1525,7 @@ static int ovl_get_workdir(struct super_block *sb, struct ovl_fs *ofs,
 }
 
 static int ovl_get_indexdir(struct super_block *sb, struct ovl_fs *ofs,
-			    struct ovl_entry *oe, struct path *upperpath)
+			    struct ovl_entry *oe, const struct path *upperpath)
 {
 	struct vfsmount *mnt = ovl_upper_mnt(ofs);
 	struct dentry *indexdir;
diff --git a/fs/overlayfs/util.c b/fs/overlayfs/util.c
index 87f811c089e4..81a57a8d80d9 100644
--- a/fs/overlayfs/util.c
+++ b/fs/overlayfs/util.c
@@ -490,7 +490,7 @@ bool ovl_is_whiteout(struct dentry *dentry)
 	return inode && IS_WHITEOUT(inode);
 }
 
-struct file *ovl_path_open(struct path *path, int flags)
+struct file *ovl_path_open(const struct path *path, int flags)
 {
 	struct inode *inode = d_inode(path->dentry);
 	struct user_namespace *real_mnt_userns = mnt_user_ns(path->mnt);
@@ -578,7 +578,7 @@ void ovl_copy_up_end(struct dentry *dentry)
 	ovl_inode_unlock(d_inode(dentry));
 }
 
-bool ovl_path_check_origin_xattr(struct ovl_fs *ofs, struct path *path)
+bool ovl_path_check_origin_xattr(struct ovl_fs *ofs, const struct path *path)
 {
 	int res;
 
@@ -591,7 +591,7 @@ bool ovl_path_check_origin_xattr(struct ovl_fs *ofs, struct path *path)
 	return false;
 }
 
-bool ovl_path_check_dir_xattr(struct ovl_fs *ofs, struct path *path,
+bool ovl_path_check_dir_xattr(struct ovl_fs *ofs, const struct path *path,
 			       enum ovl_xattr ox)
 {
 	int res;
@@ -971,7 +971,7 @@ int ovl_lock_rename_workdir(struct dentry *workdir, struct dentry *upperdir)
 }
 
 /* err < 0, 0 if no metacopy xattr, 1 if metacopy xattr found */
-int ovl_check_metacopy_xattr(struct ovl_fs *ofs, struct path *path)
+int ovl_check_metacopy_xattr(struct ovl_fs *ofs, const struct path *path)
 {
 	int res;
 
@@ -1015,7 +1015,7 @@ bool ovl_is_metacopy_dentry(struct dentry *dentry)
 	return (oe->numlower > 1);
 }
 
-char *ovl_get_redirect_xattr(struct ovl_fs *ofs, struct path *path, int padding)
+char *ovl_get_redirect_xattr(struct ovl_fs *ofs, const struct path *path, int padding)
 {
 	int res;
 	char *s, *next, *buf = NULL;
-- 
2.30.2

[PATCH 06/11] do_proc_readlink(): constify path

[Al Viro]

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
 fs/proc/base.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/proc/base.c b/fs/proc/base.c
index e347b8ce140c..2d9429bf51fa 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -1761,7 +1761,7 @@ static const char *proc_pid_get_link(struct dentry *dentry,
 	return ERR_PTR(error);
 }
 
-static int do_proc_readlink(struct path *path, char __user *buffer, int buflen)
+static int do_proc_readlink(const struct path *path, char __user *buffer, int buflen)
 {
 	char *tmp = kmalloc(PATH_MAX, GFP_KERNEL);
 	char *pathname;
-- 
2.30.2

[PATCH 07/11] __io_setxattr(): constify path

[Al Viro]

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
 io_uring/xattr.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/io_uring/xattr.c b/io_uring/xattr.c
index 84180afd090b..99df641594d7 100644
--- a/io_uring/xattr.c
+++ b/io_uring/xattr.c
@@ -206,7 +206,7 @@ int io_fsetxattr_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 }
 
 static int __io_setxattr(struct io_kiocb *req, unsigned int issue_flags,
-			struct path *path)
+			const struct path *path)
 {
 	struct io_xattr *ix = io_kiocb_to_cmd(req, struct io_xattr);
 	int ret;
-- 
2.30.2

[PATCH 08/11] audit_init_parent(): constify path

[Al Viro]

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
 kernel/audit_watch.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/audit_watch.c b/kernel/audit_watch.c
index 4b0957aa2cd4..65075f1e4ac8 100644
--- a/kernel/audit_watch.c
+++ b/kernel/audit_watch.c
@@ -133,7 +133,7 @@ int audit_watch_compare(struct audit_watch *watch, unsigned long ino, dev_t dev)
 }
 
 /* Initialize a parent watch entry. */
-static struct audit_parent *audit_init_parent(struct path *path)
+static struct audit_parent *audit_init_parent(const struct path *path)
 {
 	struct inode *inode = d_backing_inode(path->dentry);
 	struct audit_parent *parent;
-- 
2.30.2

[PATCH 09/11] nd_jump_link(): constify path

[Al Viro]

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
 fs/namei.c            | 2 +-
 include/linux/namei.h | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/fs/namei.c b/fs/namei.c
index 6a5ab1a6f01b..8533087e5dac 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -986,7 +986,7 @@ static int nd_jump_root(struct nameidata *nd)
  * Helper to directly jump to a known parsed path from ->get_link,
  * caller must have taken a reference to path beforehand.
  */
-int nd_jump_link(struct path *path)
+int nd_jump_link(const struct path *path)
 {
 	int error = -ELOOP;
 	struct nameidata *nd = current->nameidata;
diff --git a/include/linux/namei.h b/include/linux/namei.h
index caeb08a98536..00fee52df842 100644
--- a/include/linux/namei.h
+++ b/include/linux/namei.h
@@ -83,7 +83,7 @@ extern int follow_up(struct path *);
 extern struct dentry *lock_rename(struct dentry *, struct dentry *);
 extern void unlock_rename(struct dentry *, struct dentry *);
 
-extern int __must_check nd_jump_link(struct path *path);
+extern int __must_check nd_jump_link(const struct path *path);
 
 static inline void nd_terminate_link(void *name, size_t len, size_t maxlen)
 {
-- 
2.30.2

[PATCH 10/11] spufs: constify path

[Al Viro]

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
 arch/powerpc/platforms/cell/spufs/inode.c | 6 +++---
 arch/powerpc/platforms/cell/spufs/spufs.h | 2 +-
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/arch/powerpc/platforms/cell/spufs/inode.c b/arch/powerpc/platforms/cell/spufs/inode.c
index 320008528edd..dbcfe361831a 100644
--- a/arch/powerpc/platforms/cell/spufs/inode.c
+++ b/arch/powerpc/platforms/cell/spufs/inode.c
@@ -275,7 +275,7 @@ spufs_mkdir(struct inode *dir, struct dentry *dentry, unsigned int flags,
 	return ret;
 }
 
-static int spufs_context_open(struct path *path)
+static int spufs_context_open(const struct path *path)
 {
 	int ret;
 	struct file *filp;
@@ -491,7 +491,7 @@ spufs_mkgang(struct inode *dir, struct dentry *dentry, umode_t mode)
 	return ret;
 }
 
-static int spufs_gang_open(struct path *path)
+static int spufs_gang_open(const struct path *path)
 {
 	int ret;
 	struct file *filp;
@@ -536,7 +536,7 @@ static int spufs_create_gang(struct inode *inode,
 
 static struct file_system_type spufs_type;
 
-long spufs_create(struct path *path, struct dentry *dentry,
+long spufs_create(const struct path *path, struct dentry *dentry,
 		unsigned int flags, umode_t mode, struct file *filp)
 {
 	struct inode *dir = d_inode(path->dentry);
diff --git a/arch/powerpc/platforms/cell/spufs/spufs.h b/arch/powerpc/platforms/cell/spufs/spufs.h
index 23c6799cfa5a..af048b6dd30a 100644
--- a/arch/powerpc/platforms/cell/spufs/spufs.h
+++ b/arch/powerpc/platforms/cell/spufs/spufs.h
@@ -232,7 +232,7 @@ extern const struct spufs_tree_descr spufs_dir_debug_contents[];
 extern struct spufs_calls spufs_calls;
 struct coredump_params;
 long spufs_run_spu(struct spu_context *ctx, u32 *npc, u32 *status);
-long spufs_create(struct path *nd, struct dentry *dentry, unsigned int flags,
+long spufs_create(const struct path *nd, struct dentry *dentry, unsigned int flags,
 			umode_t mode, struct file *filp);
 /* ELF coredump callbacks for writing SPU ELF notes */
 extern int spufs_coredump_extra_notes_size(void);
-- 
2.30.2

[PATCH 11/11] ecryptfs: constify path

[Al Viro]

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
 fs/ecryptfs/ecryptfs_kernel.h | 2 +-
 fs/ecryptfs/file.c            | 2 +-
 fs/ecryptfs/inode.c           | 2 +-
 fs/ecryptfs/main.c            | 2 +-
 4 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/fs/ecryptfs/ecryptfs_kernel.h b/fs/ecryptfs/ecryptfs_kernel.h
index 5f2b49e13731..f2ed0c0266cb 100644
--- a/fs/ecryptfs/ecryptfs_kernel.h
+++ b/fs/ecryptfs/ecryptfs_kernel.h
@@ -506,7 +506,7 @@ ecryptfs_dentry_to_lower(struct dentry *dentry)
 	return ((struct ecryptfs_dentry_info *)dentry->d_fsdata)->lower_path.dentry;
 }
 
-static inline struct path *
+static inline const struct path *
 ecryptfs_dentry_to_lower_path(struct dentry *dentry)
 {
 	return &((struct ecryptfs_dentry_info *)dentry->d_fsdata)->lower_path;
diff --git a/fs/ecryptfs/file.c b/fs/ecryptfs/file.c
index 18d5b91cb573..195f7c2a16e8 100644
--- a/fs/ecryptfs/file.c
+++ b/fs/ecryptfs/file.c
@@ -33,7 +33,7 @@ static ssize_t ecryptfs_read_update_atime(struct kiocb *iocb,
 				struct iov_iter *to)
 {
 	ssize_t rc;
-	struct path *path;
+	const struct path *path;
 	struct file *file = iocb->ki_filp;
 
 	rc = generic_file_read_iter(iocb, to);
diff --git a/fs/ecryptfs/inode.c b/fs/ecryptfs/inode.c
index 16d50dface59..c214fe0981bd 100644
--- a/fs/ecryptfs/inode.c
+++ b/fs/ecryptfs/inode.c
@@ -317,7 +317,7 @@ static int ecryptfs_i_size_read(struct dentry *dentry, struct inode *inode)
 static struct dentry *ecryptfs_lookup_interpose(struct dentry *dentry,
 				     struct dentry *lower_dentry)
 {
-	struct path *path = ecryptfs_dentry_to_lower_path(dentry->d_parent);
+	const struct path *path = ecryptfs_dentry_to_lower_path(dentry->d_parent);
 	struct inode *inode, *lower_inode;
 	struct ecryptfs_dentry_info *dentry_info;
 	int rc = 0;
diff --git a/fs/ecryptfs/main.c b/fs/ecryptfs/main.c
index 2dd23a82e0de..2dc927ba067f 100644
--- a/fs/ecryptfs/main.c
+++ b/fs/ecryptfs/main.c
@@ -105,7 +105,7 @@ static int ecryptfs_init_lower_file(struct dentry *dentry,
 				    struct file **lower_file)
 {
 	const struct cred *cred = current_cred();
-	struct path *path = ecryptfs_dentry_to_lower_path(dentry);
+	const struct path *path = ecryptfs_dentry_to_lower_path(dentry);
 	int rc;
 
 	rc = ecryptfs_privileged_open(lower_file, path->dentry, path->mnt,
-- 
2.30.2

Re: [PATCHES] struct path constification

[Christian Brauner]

On Sat, Aug 20, 2022 at 07:10:38PM +0100, Al Viro wrote:
> 	This is mostly whack-a-mole stuff - a bunch of places
> are passing struct path pointers around, without bothering
> to mark them const, even though they are not going to try
> and modify the contents of struct path.
> 
> 	It's a bad practice, since there are invariants along
> the lines of "file->f_path stays unchanged open-to-release"
> and verifying those can get very unpleasant when you are
> forced to take detours down the long call chains that could've
> been avoided.
> 
> 	Patches in that pile are independent from each other
> and if anyone wants to grab some of them into subsystem's
> tree - just say so; I'll be happy to exclude those from the
> vfs.git branch if they go into another tree.
> 
> 	Currently they are in vfs.git#work.path; individual
> patches in followups.
> 

Looks good,
Reviewed-by: Christian Brauner (Microsoft) <brauner@kernel.org>