fs: port ->mkdir() to pass mnt_idmap

Convert to struct mnt_idmap.

Last cycle we merged the necessary infrastructure in
256c8ae ("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 <[email protected]>
Reviewed-by: Christoph Hellwig <[email protected]>
Signed-off-by: Christian Brauner (Microsoft) <[email protected]>

Documentation/filesystems/locking.rst

@@ -61,7 +61,7 @@ prototypes::
 	int (*link) (struct dentry *,struct inode *,struct dentry *);
 	int (*unlink) (struct inode *,struct dentry *);
 	int (*symlink) (struct mnt_idmap *, struct inode *,struct dentry *,const char *);
-	int (*mkdir) (struct inode *,struct dentry *,umode_t);
+	int (*mkdir) (struct mnt_idmap *, struct inode *,struct dentry *,umode_t);
 	int (*rmdir) (struct inode *,struct dentry *);
 	int (*mknod) (struct inode *,struct dentry *,umode_t,dev_t);
 	int (*rename) (struct inode *, struct dentry *,

Documentation/filesystems/vfs.rst

@@ -426,7 +426,7 @@ As of kernel 2.6.22, the following members are defined:
 		int (*link) (struct dentry *,struct inode *,struct dentry *);
 		int (*unlink) (struct inode *,struct dentry *);
 		int (*symlink) (struct mnt_idmap *, struct inode *,struct dentry *,const char *);
-		int (*mkdir) (struct user_namespace *, struct inode *,struct dentry *,umode_t);
+		int (*mkdir) (struct mnt_idmap *, struct inode *,struct dentry *,umode_t);
 		int (*rmdir) (struct inode *,struct dentry *);
 		int (*mknod) (struct user_namespace *, struct inode *,struct dentry *,umode_t,dev_t);
 		int (*rename) (struct user_namespace *, struct inode *, struct dentry *,

fs/9p/vfs_inode.c

@@ -704,14 +704,14 @@ v9fs_vfs_create(struct mnt_idmap *idmap, struct inode *dir,
 
 /**
  * v9fs_vfs_mkdir - VFS mkdir hook to create a directory
- * @mnt_userns: The user namespace of the mount
+ * @idmap: idmap of the mount
  * @dir:  inode that is being unlinked
  * @dentry: dentry that is being unlinked
  * @mode: mode for new directory
  *
  */
 
-static int v9fs_vfs_mkdir(struct user_namespace *mnt_userns, struct inode *dir,
+static int v9fs_vfs_mkdir(struct mnt_idmap *idmap, struct inode *dir,
 			  struct dentry *dentry, umode_t mode)
 {
 	int err;

fs/9p/vfs_inode_dotl.c

@@ -357,14 +357,14 @@ v9fs_vfs_atomic_open_dotl(struct inode *dir, struct dentry *dentry,
 
 /**
  * v9fs_vfs_mkdir_dotl - VFS mkdir hook to create a directory
- * @mnt_userns: The user namespace of the mount
+ * @idmap: The idmap of the mount
  * @dir:  inode that is being unlinked
  * @dentry: dentry that is being unlinked
  * @omode: mode for new directory
  *
  */
 
-static int v9fs_vfs_mkdir_dotl(struct user_namespace *mnt_userns,
+static int v9fs_vfs_mkdir_dotl(struct mnt_idmap *idmap,
 			       struct inode *dir, struct dentry *dentry,
 			       umode_t omode)
 {

fs/affs/affs.h

@@ -169,7 +169,7 @@ extern struct dentry *affs_lookup(struct inode *dir, struct dentry *dentry, unsi
 extern int	affs_unlink(struct inode *dir, struct dentry *dentry);
 extern int	affs_create(struct mnt_idmap *idmap, struct inode *dir,
 			struct dentry *dentry, umode_t mode, bool);
-extern int	affs_mkdir(struct user_namespace *mnt_userns, struct inode *dir,
+extern int	affs_mkdir(struct mnt_idmap *idmap, struct inode *dir,
 			struct dentry *dentry, umode_t mode);
 extern int	affs_rmdir(struct inode *dir, struct dentry *dentry);
 extern int	affs_link(struct dentry *olddentry, struct inode *dir,

fs/affs/namei.c

@@ -274,7 +274,7 @@ affs_create(struct mnt_idmap *idmap, struct inode *dir,
 }
 
 int
-affs_mkdir(struct user_namespace *mnt_userns, struct inode *dir,
+affs_mkdir(struct mnt_idmap *idmap, struct inode *dir,
 	   struct dentry *dentry, umode_t mode)
 {
 	struct inode		*inode;

fs/afs/dir.c

@@ -30,7 +30,7 @@ static bool afs_lookup_filldir(struct dir_context *ctx, const char *name, int nl
 			      loff_t fpos, u64 ino, unsigned dtype);
 static int afs_create(struct mnt_idmap *idmap, struct inode *dir,
 		      struct dentry *dentry, umode_t mode, bool excl);
-static int afs_mkdir(struct user_namespace *mnt_userns, struct inode *dir,
+static int afs_mkdir(struct mnt_idmap *idmap, struct inode *dir,
 		     struct dentry *dentry, umode_t mode);
 static int afs_rmdir(struct inode *dir, struct dentry *dentry);
 static int afs_unlink(struct inode *dir, struct dentry *dentry);
@@ -1332,7 +1332,7 @@ static const struct afs_operation_ops afs_mkdir_operation = {
 /*
  * create a directory on an AFS filesystem
  */
-static int afs_mkdir(struct user_namespace *mnt_userns, struct inode *dir,
+static int afs_mkdir(struct mnt_idmap *idmap, struct inode *dir,
 		     struct dentry *dentry, umode_t mode)
 {
 	struct afs_operation *op;

fs/autofs/root.c

@@ -15,7 +15,7 @@ static int autofs_dir_symlink(struct mnt_idmap *, struct inode *,
 			      struct dentry *, const char *);
 static int autofs_dir_unlink(struct inode *, struct dentry *);
 static int autofs_dir_rmdir(struct inode *, struct dentry *);
-static int autofs_dir_mkdir(struct user_namespace *, struct inode *,
+static int autofs_dir_mkdir(struct mnt_idmap *, struct inode *,
 			    struct dentry *, umode_t);
 static long autofs_root_ioctl(struct file *, unsigned int, unsigned long);
 #ifdef CONFIG_COMPAT
@@ -720,7 +720,7 @@ static int autofs_dir_rmdir(struct inode *dir, struct dentry *dentry)
 	return 0;
 }
 
-static int autofs_dir_mkdir(struct user_namespace *mnt_userns,
+static int autofs_dir_mkdir(struct mnt_idmap *idmap,
 			    struct inode *dir, struct dentry *dentry,
 			    umode_t mode)
 {

fs/bad_inode.c

@@ -58,7 +58,7 @@ static int bad_inode_symlink(struct mnt_idmap *idmap,
 	return -EIO;
 }
 
-static int bad_inode_mkdir(struct user_namespace *mnt_userns, struct inode *dir,
+static int bad_inode_mkdir(struct mnt_idmap *idmap, struct inode *dir,
 			   struct dentry *dentry, umode_t mode)
 {
 	return -EIO;

fs/btrfs/inode.c

@@ -6839,9 +6839,10 @@ static int btrfs_link(struct dentry *old_dentry, struct inode *dir,
 	return err;
 }
 
-static int btrfs_mkdir(struct user_namespace *mnt_userns, struct inode *dir,
+static int btrfs_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 = new_inode(dir->i_sb);

fs/ceph/dir.c

@@ -971,7 +971,7 @@ static int ceph_symlink(struct mnt_idmap *idmap, struct inode *dir,
 	return err;
 }
 
-static int ceph_mkdir(struct user_namespace *mnt_userns, struct inode *dir,
+static int ceph_mkdir(struct mnt_idmap *idmap, struct inode *dir,
 		      struct dentry *dentry, umode_t mode)
 {
 	struct ceph_mds_client *mdsc = ceph_sb_to_mdsc(dir->i_sb);

fs/cifs/cifsfs.h

@@ -59,7 +59,7 @@ extern int cifs_unlink(struct inode *dir, struct dentry *dentry);
 extern int cifs_hardlink(struct dentry *, struct inode *, struct dentry *);
 extern int cifs_mknod(struct user_namespace *, struct inode *, struct dentry *,
 		      umode_t, dev_t);
-extern int cifs_mkdir(struct user_namespace *, struct inode *, struct dentry *,
+extern int cifs_mkdir(struct mnt_idmap *, struct inode *, struct dentry *,
 		      umode_t);
 extern int cifs_rmdir(struct inode *, struct dentry *);
 extern int cifs_rename2(struct user_namespace *, struct inode *,

fs/cifs/inode.c

@@ -1910,7 +1910,7 @@ cifs_posix_mkdir(struct inode *inode, struct dentry *dentry, umode_t mode,
 }
 #endif /* CONFIG_CIFS_ALLOW_INSECURE_LEGACY */
 
-int cifs_mkdir(struct user_namespace *mnt_userns, struct inode *inode,
+int cifs_mkdir(struct mnt_idmap *idmap, struct inode *inode,
 	       struct dentry *direntry, umode_t mode)
 {
 	int rc = 0;

fs/coda/dir.c

@@ -166,7 +166,7 @@ static int coda_create(struct mnt_idmap *idmap, struct inode *dir,
 	return error;
 }
 
-static int coda_mkdir(struct user_namespace *mnt_userns, struct inode *dir,
+static int coda_mkdir(struct mnt_idmap *idmap, struct inode *dir,
 		      struct dentry *de, umode_t mode)
 {
 	struct inode *inode;

fs/configfs/dir.c

@@ -1251,7 +1251,7 @@ int configfs_depend_item_unlocked(struct configfs_subsystem *caller_subsys,
 }
 EXPORT_SYMBOL(configfs_depend_item_unlocked);
 
-static int configfs_mkdir(struct user_namespace *mnt_userns, struct inode *dir,
+static int configfs_mkdir(struct mnt_idmap *idmap, struct inode *dir,
 			  struct dentry *dentry, umode_t mode)
 {
 	int ret = 0;

fs/ecryptfs/inode.c

@@ -495,7 +495,7 @@ static int ecryptfs_symlink(struct mnt_idmap *idmap,
 	return rc;
 }
 
-static int ecryptfs_mkdir(struct user_namespace *mnt_userns, struct inode *dir,
+static int ecryptfs_mkdir(struct mnt_idmap *idmap, struct inode *dir,
 			  struct dentry *dentry, umode_t mode)
 {
 	int rc;

fs/exfat/namei.c

@@ -834,7 +834,7 @@ static int exfat_unlink(struct inode *dir, struct dentry *dentry)
 	return err;
 }
 
-static int exfat_mkdir(struct user_namespace *mnt_userns, struct inode *dir,
+static int exfat_mkdir(struct mnt_idmap *idmap, struct inode *dir,
 		       struct dentry *dentry, umode_t mode)
 {
 	struct super_block *sb = dir->i_sb;

fs/ext2/namei.c

@@ -225,7 +225,7 @@ static int ext2_link (struct dentry * old_dentry, struct inode * dir,
 	return err;
 }
 
-static int ext2_mkdir(struct user_namespace * mnt_userns,
+static int ext2_mkdir(struct mnt_idmap * idmap,
 	struct inode * dir, struct dentry * dentry, umode_t mode)
 {
 	struct inode * inode;

fs/ext4/namei.c

@@ -2973,9 +2973,10 @@ int ext4_init_new_dir(handle_t *handle, struct inode *dir,
 	return err;
 }
 
-static int ext4_mkdir(struct user_namespace *mnt_userns, struct inode *dir,
+static int ext4_mkdir(struct mnt_idmap *idmap, struct inode *dir,
 		      struct dentry *dentry, umode_t mode)
 {
+	struct user_namespace *mnt_userns = mnt_idmap_owner(idmap);
 	handle_t *handle;
 	struct inode *inode;
 	int err, err2 = 0, credits, retries = 0;

fs/f2fs/namei.c

@@ -741,9 +741,10 @@ static int f2fs_symlink(struct mnt_idmap *idmap, struct inode *dir,
 	return err;
 }
 
-static int f2fs_mkdir(struct user_namespace *mnt_userns, struct inode *dir,
+static int f2fs_mkdir(struct mnt_idmap *idmap, struct inode *dir,
 		      struct dentry *dentry, umode_t mode)
 {
+	struct user_namespace *mnt_userns = mnt_idmap_owner(idmap);
 	struct f2fs_sb_info *sbi = F2FS_I_SB(dir);
 	struct inode *inode;
 	int err;

fs/fat/namei_msdos.c

@@ -339,7 +339,7 @@ static int msdos_rmdir(struct inode *dir, struct dentry *dentry)
 }
 
 /***** Make a directory */
-static int msdos_mkdir(struct user_namespace *mnt_userns, struct inode *dir,
+static int msdos_mkdir(struct mnt_idmap *idmap, struct inode *dir,
 		       struct dentry *dentry, umode_t mode)
 {
 	struct super_block *sb = dir->i_sb;

fs/fat/namei_vfat.c

@@ -844,7 +844,7 @@ static int vfat_unlink(struct inode *dir, struct dentry *dentry)
 	return err;
 }
 
-static int vfat_mkdir(struct user_namespace *mnt_userns, struct inode *dir,
+static int vfat_mkdir(struct mnt_idmap *idmap, struct inode *dir,
 		      struct dentry *dentry, umode_t mode)
 {
 	struct super_block *sb = dir->i_sb;

fs/fuse/dir.c

@@ -819,7 +819,7 @@ static int fuse_tmpfile(struct user_namespace *mnt_userns, struct inode *dir,
 	return err;
 }
 
-static int fuse_mkdir(struct user_namespace *mnt_userns, struct inode *dir,
+static int fuse_mkdir(struct mnt_idmap *idmap, struct inode *dir,
 		      struct dentry *entry, umode_t mode)
 {
 	struct fuse_mkdir_in inarg;

fs/gfs2/inode.c

@@ -1229,15 +1229,15 @@ static int gfs2_symlink(struct mnt_idmap *idmap, struct inode *dir,
 
 /**
  * gfs2_mkdir - Make a directory
- * @mnt_userns: User namespace of the mount the inode was found from
+ * @idmap: idmap of the mount the inode was found from
  * @dir: The parent directory of the new one
  * @dentry: The dentry of the new directory
  * @mode: The mode of the new directory
  *
  * Returns: errno
  */
 
-static int gfs2_mkdir(struct user_namespace *mnt_userns, struct inode *dir,
+static int gfs2_mkdir(struct mnt_idmap *idmap, struct inode *dir,
 		      struct dentry *dentry, umode_t mode)
 {
 	unsigned dsize = gfs2_max_stuffed_size(GFS2_I(dir));

fs/hfs/dir.c

@@ -219,7 +219,7 @@ static int hfs_create(struct mnt_idmap *idmap, struct inode *dir,
  * in a directory, given the inode for the parent directory and the
  * name (and its length) of the new directory.
  */
-static int hfs_mkdir(struct user_namespace *mnt_userns, struct inode *dir,
+static int hfs_mkdir(struct mnt_idmap *idmap, struct inode *dir,
 		     struct dentry *dentry, umode_t mode)
 {
 	struct inode *inode;

fs/hfsplus/dir.c

@@ -523,7 +523,7 @@ static int hfsplus_create(struct mnt_idmap *idmap, struct inode *dir,
 	return hfsplus_mknod(&init_user_ns, dir, dentry, mode, 0);
 }
 
-static int hfsplus_mkdir(struct user_namespace *mnt_userns, struct inode *dir,
+static int hfsplus_mkdir(struct mnt_idmap *idmap, struct inode *dir,
 			 struct dentry *dentry, umode_t mode)
 {
 	return hfsplus_mknod(&init_user_ns, dir, dentry, mode | S_IFDIR, 0);

fs/hostfs/hostfs_kern.c

@@ -671,7 +671,7 @@ static int hostfs_symlink(struct mnt_idmap *idmap, struct inode *ino,
 	return err;
 }
 
-static int hostfs_mkdir(struct user_namespace *mnt_userns, struct inode *ino,
+static int hostfs_mkdir(struct mnt_idmap *idmap, struct inode *ino,
 			struct dentry *dentry, umode_t mode)
 {
 	char *file;

fs/hpfs/namei.c

@@ -20,7 +20,7 @@ static void hpfs_update_directory_times(struct inode *dir)
 	hpfs_write_inode_nolock(dir);
 }
 
-static int hpfs_mkdir(struct user_namespace *mnt_userns, struct inode *dir,
+static int hpfs_mkdir(struct mnt_idmap *idmap, struct inode *dir,
 		      struct dentry *dentry, umode_t mode)
 {
 	const unsigned char *name = dentry->d_name.name;

fs/hugetlbfs/inode.c

@@ -1033,7 +1033,7 @@ static int hugetlbfs_mknod(struct user_namespace *mnt_userns, struct inode *dir,
 	return 0;
 }
 
-static int hugetlbfs_mkdir(struct user_namespace *mnt_userns, struct inode *dir,
+static int hugetlbfs_mkdir(struct mnt_idmap *idmap, struct inode *dir,
 			   struct dentry *dentry, umode_t mode)
 {
 	int retval = hugetlbfs_mknod(&init_user_ns, dir, dentry,

fs/jffs2/dir.c

@@ -32,7 +32,7 @@ static int jffs2_link (struct dentry *,struct inode *,struct dentry *);
 static int jffs2_unlink (struct inode *,struct dentry *);
 static int jffs2_symlink (struct mnt_idmap *, struct inode *,
 			  struct dentry *, const char *);
-static int jffs2_mkdir (struct user_namespace *, struct inode *,struct dentry *,
+static int jffs2_mkdir (struct mnt_idmap *, struct inode *,struct dentry *,
 			umode_t);
 static int jffs2_rmdir (struct inode *,struct dentry *);
 static int jffs2_mknod (struct user_namespace *, struct inode *,struct dentry *,
@@ -442,7 +442,7 @@ static int jffs2_symlink (struct mnt_idmap *idmap, struct inode *dir_i,
 }
 
 
-static int jffs2_mkdir (struct user_namespace *mnt_userns, struct inode *dir_i,
+static int jffs2_mkdir (struct mnt_idmap *idmap, struct inode *dir_i,
 		        struct dentry *dentry, umode_t mode)
 {
 	struct jffs2_inode_info *f, *dir_f;

fs/jfs/namei.c

@@ -192,7 +192,7 @@ static int jfs_create(struct mnt_idmap *idmap, struct inode *dip,
  * note:
  * EACCES: user needs search+write permission on the parent directory
  */
-static int jfs_mkdir(struct user_namespace *mnt_userns, struct inode *dip,
+static int jfs_mkdir(struct mnt_idmap *idmap, struct inode *dip,
 		     struct dentry *dentry, umode_t mode)
 {
 	int rc = 0;

fs/kernfs/dir.c

@@ -1200,7 +1200,7 @@ static struct dentry *kernfs_iop_lookup(struct inode *dir,
 	return d_splice_alias(inode, dentry);
 }
 
-static int kernfs_iop_mkdir(struct user_namespace *mnt_userns,
+static int kernfs_iop_mkdir(struct mnt_idmap *idmap,
 			    struct inode *dir, struct dentry *dentry,
 			    umode_t mode)
 {

fs/minix/namei.c

@@ -111,7 +111,7 @@ static int minix_link(struct dentry * old_dentry, struct inode * dir,
 	return add_nondir(dentry, inode);
 }
 
-static int minix_mkdir(struct user_namespace *mnt_userns, struct inode *dir,
+static int minix_mkdir(struct mnt_idmap *idmap, struct inode *dir,
 		       struct dentry *dentry, umode_t mode)
 {
 	struct inode * inode;

fs/namei.c

@@ -4044,7 +4044,7 @@ int vfs_mkdir(struct mnt_idmap *idmap, struct inode *dir,
 	if (max_links && dir->i_nlink >= max_links)
 		return -EMLINK;
 
-	error = dir->i_op->mkdir(mnt_userns, dir, dentry, mode);
+	error = dir->i_op->mkdir(idmap, dir, dentry, mode);
 	if (!error)
 		fsnotify_mkdir(dir, dentry);
 	return error;

fs/nfs/dir.c

@@ -2352,7 +2352,7 @@ EXPORT_SYMBOL_GPL(nfs_mknod);
 /*
  * See comments for nfs_proc_create regarding failed operations.
  */
-int nfs_mkdir(struct user_namespace *mnt_userns, struct inode *dir,
+int nfs_mkdir(struct mnt_idmap *idmap, struct inode *dir,
 	      struct dentry *dentry, umode_t mode)
 {
 	struct iattr attr;

fs/nfs/internal.h

@@ -386,7 +386,7 @@ struct dentry *nfs_lookup(struct inode *, struct dentry *, unsigned int);
 void nfs_d_prune_case_insensitive_aliases(struct inode *inode);
 int nfs_create(struct mnt_idmap *, struct inode *, struct dentry *,
 	       umode_t, bool);
-int nfs_mkdir(struct user_namespace *, struct inode *, struct dentry *,
+int nfs_mkdir(struct mnt_idmap *, struct inode *, struct dentry *,
 	      umode_t);
 int nfs_rmdir(struct inode *, struct dentry *);
 int nfs_unlink(struct inode *, struct dentry *);

fs/nilfs2/namei.c

@@ -202,7 +202,7 @@ static int nilfs_link(struct dentry *old_dentry, struct inode *dir,
 	return err;
 }
 
-static int nilfs_mkdir(struct user_namespace *mnt_userns, struct inode *dir,
+static int nilfs_mkdir(struct mnt_idmap *idmap, struct inode *dir,
 		       struct dentry *dentry, umode_t mode)
 {
 	struct inode *inode;