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>

1 files changed, 7 insertions, 11 deletions

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);