fs: port acl to 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>

4 files changed, 18 insertions, 23 deletions

diff --git a/fs/ntfs3/inode.c b/fs/ntfs3/inode.c
index 20b953871574..2a9347e747e5 100644
--- a/fs/ntfs3/inode.c
+++ b/fs/ntfs3/inode.c
@@ -1185,13 +1185,14 @@ out:
  * 
  * NOTE: if fnd != NULL (ntfs_atomic_open) then @dir is locked
  */
-struct inode *ntfs_create_inode(struct user_namespace *mnt_userns,
+struct inode *ntfs_create_inode(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)
 {
 	int err;
+	struct user_namespace *mnt_userns = mnt_idmap_owner(idmap);
 	struct super_block *sb = dir->i_sb;
 	struct ntfs_sb_info *sbi = sb->s_fs_info;
 	const struct qstr *name = &dentry->d_name;
@@ -1614,7 +1615,7 @@ struct inode *ntfs_create_inode(struct user_namespace *mnt_userns,
 
 #ifdef CONFIG_NTFS3_FS_POSIX_ACL
 	if (!S_ISLNK(mode) && (sb->s_flags & SB_POSIXACL)) {
-		err = ntfs_init_acl(mnt_userns, inode, dir);
+		err = ntfs_init_acl(idmap, inode, dir);
 		if (err)
 			goto out7;
 	} else
diff --git a/fs/ntfs3/namei.c b/fs/ntfs3/namei.c
index 13731de39010..407fe92394e2 100644
--- a/fs/ntfs3/namei.c
+++ b/fs/ntfs3/namei.c
@@ -97,10 +97,9 @@ static struct dentry *ntfs_lookup(struct inode *dir, struct dentry *dentry,
 static int ntfs_create(struct mnt_idmap *idmap, struct inode *dir,
 		       struct dentry *dentry, umode_t mode, bool excl)
 {
-	struct user_namespace *mnt_userns = mnt_idmap_owner(idmap);
 	struct inode *inode;
 
-	inode = ntfs_create_inode(mnt_userns, dir, dentry, NULL, S_IFREG | mode,
+	inode = ntfs_create_inode(idmap, dir, dentry, NULL, S_IFREG | mode,
 				  0, NULL, 0, NULL);
 
 	return IS_ERR(inode) ? PTR_ERR(inode) : 0;
@@ -114,10 +113,9 @@ static int ntfs_create(struct mnt_idmap *idmap, struct inode *dir,
 static int ntfs_mknod(struct mnt_idmap *idmap, struct inode *dir,
 		      struct dentry *dentry, umode_t mode, dev_t rdev)
 {
-	struct user_namespace *mnt_userns = mnt_idmap_owner(idmap);
 	struct inode *inode;
 
-	inode = ntfs_create_inode(mnt_userns, dir, dentry, NULL, mode, rdev,
+	inode = ntfs_create_inode(idmap, dir, dentry, NULL, mode, rdev,
 				  NULL, 0, NULL);
 
 	return IS_ERR(inode) ? PTR_ERR(inode) : 0;
@@ -188,11 +186,10 @@ static int ntfs_unlink(struct inode *dir, struct dentry *dentry)
 static int ntfs_symlink(struct mnt_idmap *idmap, struct inode *dir,
 			struct dentry *dentry, const char *symname)
 {
-	struct user_namespace *mnt_userns = mnt_idmap_owner(idmap);
 	u32 size = strlen(symname);
 	struct inode *inode;
 
-	inode = ntfs_create_inode(mnt_userns, dir, dentry, NULL, S_IFLNK | 0777,
+	inode = ntfs_create_inode(idmap, dir, dentry, NULL, S_IFLNK | 0777,
 				  0, symname, size, NULL);
 
 	return IS_ERR(inode) ? PTR_ERR(inode) : 0;
@@ -204,10 +201,9 @@ static int ntfs_symlink(struct mnt_idmap *idmap, struct inode *dir,
 static int ntfs_mkdir(struct mnt_idmap *idmap, struct inode *dir,
 		      struct dentry *dentry, umode_t mode)
 {
-	struct user_namespace *mnt_userns = mnt_idmap_owner(idmap);
 	struct inode *inode;
 
-	inode = ntfs_create_inode(mnt_userns, dir, dentry, NULL, S_IFDIR | mode,
+	inode = ntfs_create_inode(idmap, dir, dentry, NULL, S_IFDIR | mode,
 				  0, NULL, 0, NULL);
 
 	return IS_ERR(inode) ? PTR_ERR(inode) : 0;
@@ -419,13 +415,13 @@ static int ntfs_atomic_open(struct inode *dir, struct dentry *dentry,
 
 	/*
 	 * Unfortunately I don't know how to get here correct 'struct nameidata *nd'
-	 * or 'struct user_namespace *mnt_userns'.
+	 * or 'struct mnt_idmap *idmap'.
 	 * See atomic_open in fs/namei.c.
 	 * This is why xfstest/633 failed.
-	 * Looks like ntfs_atomic_open must accept 'struct user_namespace *mnt_userns' as argument.
+	 * Looks like ntfs_atomic_open must accept 'struct mnt_idmap *idmap' as argument.
 	 */
 
-	inode = ntfs_create_inode(&init_user_ns, dir, dentry, uni, mode, 0,
+	inode = ntfs_create_inode(&nop_mnt_idmap, dir, dentry, uni, mode, 0,
 				  NULL, 0, fnd);
 	err = IS_ERR(inode) ? PTR_ERR(inode)
 			    : finish_open(file, dentry, ntfs_file_open);
diff --git a/fs/ntfs3/ntfs_fs.h b/fs/ntfs3/ntfs_fs.h
index 9b649a5b6beb..80072e5f96f7 100644
--- a/fs/ntfs3/ntfs_fs.h
+++ b/fs/ntfs3/ntfs_fs.h
@@ -708,7 +708,7 @@ int ntfs_sync_inode(struct inode *inode);
 int ntfs_flush_inodes(struct super_block *sb, struct inode *i1,
 		      struct inode *i2);
 int inode_write_data(struct inode *inode, const void *data, size_t bytes);
-struct inode *ntfs_create_inode(struct user_namespace *mnt_userns,
+struct inode *ntfs_create_inode(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,
@@ -861,7 +861,7 @@ unsigned long ntfs_names_hash(const u16 *name, size_t len, const u16 *upcase,
 struct posix_acl *ntfs_get_acl(struct inode *inode, int type, bool rcu);
 int ntfs_set_acl(struct mnt_idmap *idmap, struct dentry *dentry,
 		 struct posix_acl *acl, int type);
-int ntfs_init_acl(struct user_namespace *mnt_userns, struct inode *inode,
+int ntfs_init_acl(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 55ee27c96a4d..ff64302e87e5 100644
--- a/fs/ntfs3/xattr.c
+++ b/fs/ntfs3/xattr.c
@@ -578,7 +578,7 @@ struct posix_acl *ntfs_get_acl(struct inode *inode, int type, bool rcu)
 	return ntfs_get_acl_ex(inode, type, 0);
 }
 
-static noinline int ntfs_set_acl_ex(struct user_namespace *mnt_userns,
+static noinline int ntfs_set_acl_ex(struct mnt_idmap *idmap,
 				    struct inode *inode, struct posix_acl *acl,
 				    int type, bool init_acl)
 {
@@ -597,7 +597,7 @@ static noinline int ntfs_set_acl_ex(struct user_namespace *mnt_userns,
 	case ACL_TYPE_ACCESS:
 		/* Do not change i_mode if we are in init_acl */
 		if (acl && !init_acl) {
-			err = posix_acl_update_mode(mnt_userns, inode, &mode,
+			err = posix_acl_update_mode(idmap, inode, &mode,
 						    &acl);
 			if (err)
 				return err;
@@ -655,9 +655,7 @@ out:
 int ntfs_set_acl(struct mnt_idmap *idmap, struct dentry *dentry,
 		 struct posix_acl *acl, int type)
 {
-	struct user_namespace *mnt_userns = mnt_idmap_owner(idmap);
-
-	return ntfs_set_acl_ex(mnt_userns, d_inode(dentry), acl, type, false);
+	return ntfs_set_acl_ex(idmap, d_inode(dentry), acl, type, false);
 }
 
 /*
@@ -665,7 +663,7 @@ int ntfs_set_acl(struct mnt_idmap *idmap, struct dentry *dentry,
  *
  * Called from ntfs_create_inode().
  */
-int ntfs_init_acl(struct user_namespace *mnt_userns, struct inode *inode,
+int ntfs_init_acl(struct mnt_idmap *idmap, struct inode *inode,
 		  struct inode *dir)
 {
 	struct posix_acl *default_acl, *acl;
@@ -676,7 +674,7 @@ int ntfs_init_acl(struct user_namespace *mnt_userns, struct inode *inode,
 		return err;
 
 	if (default_acl) {
-		err = ntfs_set_acl_ex(mnt_userns, inode, default_acl,
+		err = ntfs_set_acl_ex(idmap, inode, default_acl,
 				      ACL_TYPE_DEFAULT, true);
 		posix_acl_release(default_acl);
 	} else {
@@ -685,7 +683,7 @@ int ntfs_init_acl(struct user_namespace *mnt_userns, struct inode *inode,
 
 	if (acl) {
 		if (!err)
-			err = ntfs_set_acl_ex(mnt_userns, inode, acl,
+			err = ntfs_set_acl_ex(idmap, inode, acl,
 					      ACL_TYPE_ACCESS, true);
 		posix_acl_release(acl);
 	} else {