fs: port ->getattr() to pass mnt_idmap

Convert to struct mnt_idmap.

Last cycle we merged the necessary infrastructure in
256c8aed2b42 ("fs: introduce dedicated idmap type for mounts").
This is just the conversion to struct mnt_idmap.

Currently we still pass around the plain namespace that was attached to a
mount. This is in general pretty convenient but it makes it easy to
conflate namespaces that are relevant on the filesystem with namespaces
that are relevent on the mount level. Especially for non-vfs developers
without detailed knowledge in this area this can be a potential source for
bugs.

Once the conversion to struct mnt_idmap is done all helpers down to the
really low-level helpers will take a struct mnt_idmap argument instead of
two namespace arguments. This way it becomes impossible to conflate the two
eliminating the possibility of any bugs. All of the vfs and all filesystems
only operate on struct mnt_idmap.

Acked-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>

7 files changed, 15 insertions, 15 deletions

diff --git a/fs/proc/base.c b/fs/proc/base.c
index 92166c33395d..aa7ebee00746 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -1959,14 +1959,14 @@ static struct inode *proc_pid_make_base_inode(struct super_block *sb,
 	return inode;
 }
 
-int pid_getattr(struct user_namespace *mnt_userns, const struct path *path,
+int pid_getattr(struct mnt_idmap *idmap, const struct path *path,
 		struct kstat *stat, u32 request_mask, unsigned int query_flags)
 {
 	struct inode *inode = d_inode(path->dentry);
 	struct proc_fs_info *fs_info = proc_sb_info(inode->i_sb);
 	struct task_struct *task;
 
-	generic_fillattr(&init_user_ns, inode, stat);
+	generic_fillattr(&nop_mnt_idmap, inode, stat);
 
 	stat->uid = GLOBAL_ROOT_UID;
 	stat->gid = GLOBAL_ROOT_GID;
@@ -3891,13 +3891,13 @@ static int proc_task_readdir(struct file *file, struct dir_context *ctx)
 	return 0;
 }
 
-static int proc_task_getattr(struct user_namespace *mnt_userns,
+static int proc_task_getattr(struct mnt_idmap *idmap,
 			     const struct path *path, struct kstat *stat,
 			     u32 request_mask, unsigned int query_flags)
 {
 	struct inode *inode = d_inode(path->dentry);
 	struct task_struct *p = get_proc_task(inode);
-	generic_fillattr(&init_user_ns, inode, stat);
+	generic_fillattr(&nop_mnt_idmap, inode, stat);
 
 	if (p) {
 		stat->nlink += get_nr_threads(p);
diff --git a/fs/proc/fd.c b/fs/proc/fd.c
index fc46d6fe080c..d9bda34c770d 100644
--- a/fs/proc/fd.c
+++ b/fs/proc/fd.c
@@ -344,14 +344,14 @@ int proc_fd_permission(struct user_namespace *mnt_userns,
 	return rv;
 }
 
-static int proc_fd_getattr(struct user_namespace *mnt_userns,
+static int proc_fd_getattr(struct mnt_idmap *idmap,
 			const struct path *path, struct kstat *stat,
 			u32 request_mask, unsigned int query_flags)
 {
 	struct inode *inode = d_inode(path->dentry);
 	int rv = 0;
 
-	generic_fillattr(&init_user_ns, inode, stat);
+	generic_fillattr(&nop_mnt_idmap, inode, stat);
 
 	/* If it's a directory, put the number of open fds there */
 	if (S_ISDIR(inode->i_mode)) {
diff --git a/fs/proc/generic.c b/fs/proc/generic.c
index 4464ad6a2283..8379593fa4bb 100644
--- a/fs/proc/generic.c
+++ b/fs/proc/generic.c
@@ -134,7 +134,7 @@ static int proc_notify_change(struct mnt_idmap *idmap,
 	return 0;
 }
 
-static int proc_getattr(struct user_namespace *mnt_userns,
+static int proc_getattr(struct mnt_idmap *idmap,
 			const struct path *path, struct kstat *stat,
 			u32 request_mask, unsigned int query_flags)
 {
@@ -147,7 +147,7 @@ static int proc_getattr(struct user_namespace *mnt_userns,
 		}
 	}
 
-	generic_fillattr(&init_user_ns, inode, stat);
+	generic_fillattr(&nop_mnt_idmap, inode, stat);
 	return 0;
 }
 
diff --git a/fs/proc/internal.h b/fs/proc/internal.h
index 6eb921670fc6..9dda7e54b2d0 100644
--- a/fs/proc/internal.h
+++ b/fs/proc/internal.h
@@ -162,7 +162,7 @@ extern int proc_pid_statm(struct seq_file *, struct pid_namespace *,
  * base.c
  */
 extern const struct dentry_operations pid_dentry_operations;
-extern int pid_getattr(struct user_namespace *, const struct path *,
+extern int pid_getattr(struct mnt_idmap *, const struct path *,
 		       struct kstat *, u32, unsigned int);
 extern int proc_setattr(struct mnt_idmap *, struct dentry *,
 			struct iattr *);
diff --git a/fs/proc/proc_net.c b/fs/proc/proc_net.c
index 856839b8ae8b..a0c0419872e3 100644
--- a/fs/proc/proc_net.c
+++ b/fs/proc/proc_net.c
@@ -299,7 +299,7 @@ static struct dentry *proc_tgid_net_lookup(struct inode *dir,
 	return de;
 }
 
-static int proc_tgid_net_getattr(struct user_namespace *mnt_userns,
+static int proc_tgid_net_getattr(struct mnt_idmap *idmap,
 				 const struct path *path, struct kstat *stat,
 				 u32 request_mask, unsigned int query_flags)
 {
@@ -308,7 +308,7 @@ static int proc_tgid_net_getattr(struct user_namespace *mnt_userns,
 
 	net = get_proc_task_net(inode);
 
-	generic_fillattr(&init_user_ns, inode, stat);
+	generic_fillattr(&nop_mnt_idmap, inode, stat);
 
 	if (net != NULL) {
 		stat->nlink = net->proc_net->nlink;
diff --git a/fs/proc/proc_sysctl.c b/fs/proc/proc_sysctl.c
index daba911972ec..7d111c46ca75 100644
--- a/fs/proc/proc_sysctl.c
+++ b/fs/proc/proc_sysctl.c
@@ -845,7 +845,7 @@ static int proc_sys_setattr(struct mnt_idmap *idmap,
 	return 0;
 }
 
-static int proc_sys_getattr(struct user_namespace *mnt_userns,
+static int proc_sys_getattr(struct mnt_idmap *idmap,
 			    const struct path *path, struct kstat *stat,
 			    u32 request_mask, unsigned int query_flags)
 {
@@ -856,7 +856,7 @@ static int proc_sys_getattr(struct user_namespace *mnt_userns,
 	if (IS_ERR(head))
 		return PTR_ERR(head);
 
-	generic_fillattr(&init_user_ns, inode, stat);
+	generic_fillattr(&nop_mnt_idmap, inode, stat);
 	if (table)
 		stat->mode = (stat->mode & S_IFMT) | table->mode;
 
diff --git a/fs/proc/root.c b/fs/proc/root.c
index 3c2ee3eb1138..a86e65a608da 100644
--- a/fs/proc/root.c
+++ b/fs/proc/root.c
@@ -310,11 +310,11 @@ void __init proc_root_init(void)
 	register_filesystem(&proc_fs_type);
 }
 
-static int proc_root_getattr(struct user_namespace *mnt_userns,
+static int proc_root_getattr(struct mnt_idmap *idmap,
 			     const struct path *path, struct kstat *stat,
 			     u32 request_mask, unsigned int query_flags)
 {
-	generic_fillattr(&init_user_ns, d_inode(path->dentry), stat);
+	generic_fillattr(&nop_mnt_idmap, d_inode(path->dentry), stat);
 	stat->nlink = proc_root.nlink + nr_processes();
 	return 0;
 }