fs: port ->rename() 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

@@ -64,7 +64,7 @@ prototypes::
 	int (*mkdir) (struct mnt_idmap *, struct inode *,struct dentry *,umode_t);
 	int (*rmdir) (struct inode *,struct dentry *);
 	int (*mknod) (struct mnt_idmap *, struct inode *,struct dentry *,umode_t,dev_t);
-	int (*rename) (struct inode *, struct dentry *,
+	int (*rename) (struct mnt_idmap *, struct inode *, struct dentry *,
 			struct inode *, struct dentry *, unsigned int);
 	int (*readlink) (struct dentry *, char __user *,int);
 	const char *(*get_link) (struct dentry *, struct inode *, struct delayed_call *);

Documentation/filesystems/vfs.rst

@@ -429,7 +429,7 @@ As of kernel 2.6.22, the following members are defined:
 		int (*mkdir) (struct mnt_idmap *, struct inode *,struct dentry *,umode_t);
 		int (*rmdir) (struct inode *,struct dentry *);
 		int (*mknod) (struct mnt_idmap *, struct inode *,struct dentry *,umode_t,dev_t);
-		int (*rename) (struct user_namespace *, struct inode *, struct dentry *,
+		int (*rename) (struct mnt_idmap *, struct inode *, struct dentry *,
 			       struct inode *, struct dentry *, unsigned int);
 		int (*readlink) (struct dentry *, char __user *,int);
 		const char *(*get_link) (struct dentry *, struct inode *,

drivers/android/binderfs.c

@@ -352,7 +352,7 @@ static inline bool is_binderfs_control_device(const struct dentry *dentry)
 	return info->control_dentry == dentry;
 }
 
-static int binderfs_rename(struct user_namespace *mnt_userns,
+static int binderfs_rename(struct mnt_idmap *idmap,
 			   struct inode *old_dir, struct dentry *old_dentry,
 			   struct inode *new_dir, struct dentry *new_dentry,
 			   unsigned int flags)
@@ -361,7 +361,7 @@ static int binderfs_rename(struct user_namespace *mnt_userns,
 	    is_binderfs_control_device(new_dentry))
 		return -EPERM;
 
-	return simple_rename(&init_user_ns, old_dir, old_dentry, new_dir,
+	return simple_rename(idmap, old_dir, old_dentry, new_dir,
 			     new_dentry, flags);
 }
 

fs/9p/v9fs.h

@@ -151,7 +151,7 @@ extern struct dentry *v9fs_vfs_lookup(struct inode *dir, struct dentry *dentry,
 				      unsigned int flags);
 extern int v9fs_vfs_unlink(struct inode *i, struct dentry *d);
 extern int v9fs_vfs_rmdir(struct inode *i, struct dentry *d);
-extern int v9fs_vfs_rename(struct user_namespace *mnt_userns,
+extern int v9fs_vfs_rename(struct mnt_idmap *idmap,
 			   struct inode *old_dir, struct dentry *old_dentry,
 			   struct inode *new_dir, struct dentry *new_dentry,
 			   unsigned int flags);

fs/9p/vfs_inode.c

@@ -908,7 +908,7 @@ int v9fs_vfs_rmdir(struct inode *i, struct dentry *d)
 
 /**
  * v9fs_vfs_rename - VFS hook to rename an inode
- * @mnt_userns: The user namespace of the mount
+ * @idmap: The idmap of the mount
  * @old_dir:  old dir inode
  * @old_dentry: old dentry
  * @new_dir: new dir inode
@@ -918,7 +918,7 @@ int v9fs_vfs_rmdir(struct inode *i, struct dentry *d)
  */
 
 int
-v9fs_vfs_rename(struct user_namespace *mnt_userns, struct inode *old_dir,
+v9fs_vfs_rename(struct mnt_idmap *idmap, struct inode *old_dir,
 		struct dentry *old_dentry, struct inode *new_dir,
 		struct dentry *new_dentry, unsigned int flags)
 {

fs/affs/affs.h

@@ -177,7 +177,7 @@ extern int	affs_link(struct dentry *olddentry, struct inode *dir,
 extern int	affs_symlink(struct mnt_idmap *idmap,
 			struct inode *dir, struct dentry *dentry,
 			const char *symname);
-extern int	affs_rename2(struct user_namespace *mnt_userns,
+extern int	affs_rename2(struct mnt_idmap *idmap,
 			struct inode *old_dir, struct dentry *old_dentry,
 			struct inode *new_dir, struct dentry *new_dentry,
 			unsigned int flags);

fs/affs/namei.c

@@ -503,7 +503,7 @@ affs_xrename(struct inode *old_dir, struct dentry *old_dentry,
 	return retval;
 }
 
-int affs_rename2(struct user_namespace *mnt_userns, struct inode *old_dir,
+int affs_rename2(struct mnt_idmap *idmap, struct inode *old_dir,
 		 struct dentry *old_dentry, struct inode *new_dir,
 		 struct dentry *new_dentry, unsigned int flags)
 {

fs/afs/dir.c

@@ -38,7 +38,7 @@ static int afs_link(struct dentry *from, struct inode *dir,
 		    struct dentry *dentry);
 static int afs_symlink(struct mnt_idmap *idmap, struct inode *dir,
 		       struct dentry *dentry, const char *content);
-static int afs_rename(struct user_namespace *mnt_userns, struct inode *old_dir,
+static int afs_rename(struct mnt_idmap *idmap, struct inode *old_dir,
 		      struct dentry *old_dentry, struct inode *new_dir,
 		      struct dentry *new_dentry, unsigned int flags);
 static bool afs_dir_release_folio(struct folio *folio, gfp_t gfp_flags);
@@ -1897,7 +1897,7 @@ static const struct afs_operation_ops afs_rename_operation = {
 /*
  * rename a file in an AFS filesystem and/or move it between directories
  */
-static int afs_rename(struct user_namespace *mnt_userns, struct inode *old_dir,
+static int afs_rename(struct mnt_idmap *idmap, struct inode *old_dir,
 		      struct dentry *old_dentry, struct inode *new_dir,
 		      struct dentry *new_dentry, unsigned int flags)
 {

fs/bad_inode.c

@@ -75,7 +75,7 @@ static int bad_inode_mknod(struct mnt_idmap *idmap, struct inode *dir,
 	return -EIO;
 }
 
-static int bad_inode_rename2(struct user_namespace *mnt_userns,
+static int bad_inode_rename2(struct mnt_idmap *idmap,
 			     struct inode *old_dir, struct dentry *old_dentry,
 			     struct inode *new_dir, struct dentry *new_dentry,
 			     unsigned int flags)

fs/bfs/dir.c

@@ -199,7 +199,7 @@ static int bfs_unlink(struct inode *dir, struct dentry *dentry)
 	return error;
 }
 
-static int bfs_rename(struct user_namespace *mnt_userns, struct inode *old_dir,
+static int bfs_rename(struct mnt_idmap *idmap, struct inode *old_dir,
 		      struct dentry *old_dentry, struct inode *new_dir,
 		      struct dentry *new_dentry, unsigned int flags)
 {

fs/btrfs/inode.c

@@ -9547,10 +9547,11 @@ static int btrfs_rename(struct user_namespace *mnt_userns,
 	return ret;
 }
 
-static int btrfs_rename2(struct user_namespace *mnt_userns, struct inode *old_dir,
+static int btrfs_rename2(struct mnt_idmap *idmap, struct inode *old_dir,
 			 struct dentry *old_dentry, struct inode *new_dir,
 			 struct dentry *new_dentry, unsigned int flags)
 {
+	struct user_namespace *mnt_userns = mnt_idmap_owner(idmap);
 	int ret;
 
 	if (flags & ~(RENAME_NOREPLACE | RENAME_EXCHANGE | RENAME_WHITEOUT))

fs/ceph/dir.c

@@ -1269,7 +1269,7 @@ static int ceph_unlink(struct inode *dir, struct dentry *dentry)
 	return err;
 }
 
-static int ceph_rename(struct user_namespace *mnt_userns, struct inode *old_dir,
+static int ceph_rename(struct mnt_idmap *idmap, struct inode *old_dir,
 		       struct dentry *old_dentry, struct inode *new_dir,
 		       struct dentry *new_dentry, unsigned int flags)
 {

fs/cifs/cifsfs.h

@@ -62,7 +62,7 @@ extern int cifs_mknod(struct mnt_idmap *, 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 *,
+extern int cifs_rename2(struct mnt_idmap *, struct inode *,
 			struct dentry *, struct inode *, struct dentry *,
 			unsigned int);
 extern int cifs_revalidate_file_attr(struct file *filp);

fs/cifs/inode.c

@@ -2138,7 +2138,7 @@ cifs_do_rename(const unsigned int xid, struct dentry *from_dentry,
 }
 
 int
-cifs_rename2(struct user_namespace *mnt_userns, struct inode *source_dir,
+cifs_rename2(struct mnt_idmap *idmap, struct inode *source_dir,
 	     struct dentry *source_dentry, struct inode *target_dir,
 	     struct dentry *target_dentry, unsigned int flags)
 {

fs/coda/dir.c

@@ -295,7 +295,7 @@ static int coda_rmdir(struct inode *dir, struct dentry *de)
 }
 
 /* rename */
-static int coda_rename(struct user_namespace *mnt_userns, struct inode *old_dir,
+static int coda_rename(struct mnt_idmap *idmap, struct inode *old_dir,
 		       struct dentry *old_dentry, struct inode *new_dir,
 		       struct dentry *new_dentry, unsigned int flags)
 {

fs/debugfs/inode.c

@@ -837,7 +837,7 @@ struct dentry *debugfs_rename(struct dentry *old_dir, struct dentry *old_dentry,
 
 	take_dentry_name_snapshot(&old_name, old_dentry);
 
-	error = simple_rename(&init_user_ns, d_inode(old_dir), old_dentry,
+	error = simple_rename(&nop_mnt_idmap, d_inode(old_dir), old_dentry,
 			      d_inode(new_dir), dentry, 0);
 	if (error) {
 		release_dentry_name_snapshot(&old_name);

fs/ecryptfs/inode.c

@@ -574,7 +574,7 @@ ecryptfs_mknod(struct mnt_idmap *idmap, struct inode *dir,
 }
 
 static int
-ecryptfs_rename(struct user_namespace *mnt_userns, struct inode *old_dir,
+ecryptfs_rename(struct mnt_idmap *idmap, struct inode *old_dir,
 		struct dentry *old_dentry, struct inode *new_dir,
 		struct dentry *new_dentry, unsigned int flags)
 {

fs/exfat/namei.c

@@ -1285,7 +1285,7 @@ static int __exfat_rename(struct inode *old_parent_inode,
 	return ret;
 }
 
-static int exfat_rename(struct user_namespace *mnt_userns,
+static int exfat_rename(struct mnt_idmap *idmap,
 			struct inode *old_dir, struct dentry *old_dentry,
 			struct inode *new_dir, struct dentry *new_dentry,
 			unsigned int flags)

fs/ext2/namei.c

@@ -315,7 +315,7 @@ static int ext2_rmdir (struct inode * dir, struct dentry *dentry)
 	return err;
 }
 
-static int ext2_rename (struct user_namespace * mnt_userns,
+static int ext2_rename (struct mnt_idmap * idmap,
 			struct inode * old_dir, struct dentry * old_dentry,
 			struct inode * new_dir, struct dentry * new_dentry,
 			unsigned int flags)

fs/ext4/namei.c

@@ -4162,11 +4162,12 @@ static int ext4_cross_rename(struct inode *old_dir, struct dentry *old_dentry,
 	return retval;
 }
 
-static int ext4_rename2(struct user_namespace *mnt_userns,
+static int ext4_rename2(struct mnt_idmap *idmap,
 			struct inode *old_dir, struct dentry *old_dentry,
 			struct inode *new_dir, struct dentry *new_dentry,
 			unsigned int flags)
 {
+	struct user_namespace *mnt_userns = mnt_idmap_owner(idmap);
 	int err;
 
 	if (unlikely(ext4_forced_shutdown(EXT4_SB(old_dir->i_sb))))

fs/f2fs/namei.c

@@ -1299,11 +1299,12 @@ static int f2fs_cross_rename(struct inode *old_dir, struct dentry *old_dentry,
 	return err;
 }
 
-static int f2fs_rename2(struct user_namespace *mnt_userns,
+static int f2fs_rename2(struct mnt_idmap *idmap,
 			struct inode *old_dir, struct dentry *old_dentry,
 			struct inode *new_dir, struct dentry *new_dentry,
 			unsigned int flags)
 {
+	struct user_namespace *mnt_userns = mnt_idmap_owner(idmap);
 	int err;
 
 	if (flags & ~(RENAME_NOREPLACE | RENAME_EXCHANGE | RENAME_WHITEOUT))

fs/fat/namei_msdos.c

@@ -594,7 +594,7 @@ static int do_msdos_rename(struct inode *old_dir, unsigned char *old_name,
 }
 
 /***** Rename, a wrapper for rename_same_dir & rename_diff_dir */
-static int msdos_rename(struct user_namespace *mnt_userns,
+static int msdos_rename(struct mnt_idmap *idmap,
 			struct inode *old_dir, struct dentry *old_dentry,
 			struct inode *new_dir, struct dentry *new_dentry,
 			unsigned int flags)

fs/fat/namei_vfat.c

@@ -1158,7 +1158,7 @@ static int vfat_rename_exchange(struct inode *old_dir, struct dentry *old_dentry
 	goto out;
 }
 
-static int vfat_rename2(struct user_namespace *mnt_userns, struct inode *old_dir,
+static int vfat_rename2(struct mnt_idmap *idmap, struct inode *old_dir,
 			struct dentry *old_dentry, struct inode *new_dir,
 			struct dentry *new_dentry, unsigned int flags)
 {

fs/fuse/dir.c

@@ -998,7 +998,7 @@ static int fuse_rename_common(struct inode *olddir, struct dentry *oldent,
 	return err;
 }
 
-static int fuse_rename2(struct user_namespace *mnt_userns, struct inode *olddir,
+static int fuse_rename2(struct mnt_idmap *idmap, struct inode *olddir,
 			struct dentry *oldent, struct inode *newdir,
 			struct dentry *newent, unsigned int flags)
 {

fs/gfs2/inode.c

@@ -1766,7 +1766,7 @@ static int gfs2_exchange(struct inode *odir, struct dentry *odentry,
 	return error;
 }
 
-static int gfs2_rename2(struct user_namespace *mnt_userns, struct inode *odir,
+static int gfs2_rename2(struct mnt_idmap *idmap, struct inode *odir,
 			struct dentry *odentry, struct inode *ndir,
 			struct dentry *ndentry, unsigned int flags)
 {

fs/hfs/dir.c

@@ -280,7 +280,7 @@ static int hfs_remove(struct inode *dir, struct dentry *dentry)
  * new file/directory.
  * XXX: how do you handle must_be dir?
  */
-static int hfs_rename(struct user_namespace *mnt_userns, struct inode *old_dir,
+static int hfs_rename(struct mnt_idmap *idmap, struct inode *old_dir,
 		      struct dentry *old_dentry, struct inode *new_dir,
 		      struct dentry *new_dentry, unsigned int flags)
 {

fs/hfsplus/dir.c

@@ -529,7 +529,7 @@ static int hfsplus_mkdir(struct mnt_idmap *idmap, struct inode *dir,
 	return hfsplus_mknod(&nop_mnt_idmap, dir, dentry, mode | S_IFDIR, 0);
 }
 
-static int hfsplus_rename(struct user_namespace *mnt_userns,
+static int hfsplus_rename(struct mnt_idmap *idmap,
 			  struct inode *old_dir, struct dentry *old_dentry,
 			  struct inode *new_dir, struct dentry *new_dentry,
 			  unsigned int flags)

fs/hostfs/hostfs_kern.c

@@ -734,7 +734,7 @@ static int hostfs_mknod(struct mnt_idmap *idmap, struct inode *dir,
 	return err;
 }
 
-static int hostfs_rename2(struct user_namespace *mnt_userns,
+static int hostfs_rename2(struct mnt_idmap *idmap,
 			  struct inode *old_dir, struct dentry *old_dentry,
 			  struct inode *new_dir, struct dentry *new_dentry,
 			  unsigned int flags)

fs/hpfs/namei.c

@@ -512,7 +512,7 @@ const struct address_space_operations hpfs_symlink_aops = {
 	.read_folio	= hpfs_symlink_read_folio
 };
 
-static int hpfs_rename(struct user_namespace *mnt_userns, struct inode *old_dir,
+static int hpfs_rename(struct mnt_idmap *idmap, struct inode *old_dir,
 		       struct dentry *old_dentry, struct inode *new_dir,
 		       struct dentry *new_dentry, unsigned int flags)
 {

fs/jffs2/dir.c

@@ -37,7 +37,7 @@ static int jffs2_mkdir (struct mnt_idmap *, struct inode *,struct dentry *,
 static int jffs2_rmdir (struct inode *,struct dentry *);
 static int jffs2_mknod (struct mnt_idmap *, struct inode *,struct dentry *,
 			umode_t,dev_t);
-static int jffs2_rename (struct user_namespace *, struct inode *,
+static int jffs2_rename (struct mnt_idmap *, struct inode *,
 			 struct dentry *, struct inode *, struct dentry *,
 			 unsigned int);
 
@@ -762,7 +762,7 @@ static int jffs2_mknod (struct mnt_idmap *idmap, struct inode *dir_i,
 	return ret;
 }
 
-static int jffs2_rename (struct user_namespace *mnt_userns,
+static int jffs2_rename (struct mnt_idmap *idmap,
 			 struct inode *old_dir_i, struct dentry *old_dentry,
 			 struct inode *new_dir_i, struct dentry *new_dentry,
 			 unsigned int flags)

fs/jfs/namei.c

@@ -1059,7 +1059,7 @@ static int jfs_symlink(struct mnt_idmap *idmap, struct inode *dip,
  *
  * FUNCTION:	rename a file or directory
  */
-static int jfs_rename(struct user_namespace *mnt_userns, struct inode *old_dir,
+static int jfs_rename(struct mnt_idmap *idmap, struct inode *old_dir,
 		      struct dentry *old_dentry, struct inode *new_dir,
 		      struct dentry *new_dentry, unsigned int flags)
 {

fs/kernfs/dir.c

@@ -1238,7 +1238,7 @@ static int kernfs_iop_rmdir(struct inode *dir, struct dentry *dentry)
 	return ret;
 }
 
-static int kernfs_iop_rename(struct user_namespace *mnt_userns,
+static int kernfs_iop_rename(struct mnt_idmap *idmap,
 			     struct inode *old_dir, struct dentry *old_dentry,
 			     struct inode *new_dir, struct dentry *new_dentry,
 			     unsigned int flags)

fs/libfs.c

@@ -473,7 +473,7 @@ int simple_rename_exchange(struct inode *old_dir, struct dentry *old_dentry,
 }
 EXPORT_SYMBOL_GPL(simple_rename_exchange);
 
-int simple_rename(struct user_namespace *mnt_userns, struct inode *old_dir,
+int simple_rename(struct mnt_idmap *idmap, struct inode *old_dir,
 		  struct dentry *old_dentry, struct inode *new_dir,
 		  struct dentry *new_dentry, unsigned int flags)
 {

fs/minix/namei.c

@@ -184,7 +184,7 @@ static int minix_rmdir(struct inode * dir, struct dentry *dentry)
 	return err;
 }
 
-static int minix_rename(struct user_namespace *mnt_userns,
+static int minix_rename(struct mnt_idmap *idmap,
 			struct inode *old_dir, struct dentry *old_dentry,
 			struct inode *new_dir, struct dentry *new_dentry,
 			unsigned int flags)

fs/namei.c

@@ -4786,7 +4786,7 @@ int vfs_rename(struct renamedata *rd)
 		if (error)
 			goto out;
 	}
-	error = old_dir->i_op->rename(new_mnt_userns, old_dir, old_dentry,
+	error = old_dir->i_op->rename(rd->new_mnt_idmap, old_dir, old_dentry,
 				      new_dir, new_dentry, flags);
 	if (error)
 		goto out;

fs/nfs/dir.c

@@ -2642,7 +2642,7 @@ nfs_unblock_rename(struct rpc_task *task, struct nfs_renamedata *data)
  * If these conditions are met, we can drop the dentries before doing
  * the rename.
  */
-int nfs_rename(struct user_namespace *mnt_userns, struct inode *old_dir,
+int nfs_rename(struct mnt_idmap *idmap, struct inode *old_dir,
 	       struct dentry *old_dentry, struct inode *new_dir,
 	       struct dentry *new_dentry, unsigned int flags)
 {

fs/nfs/internal.h

@@ -395,7 +395,7 @@ int nfs_symlink(struct mnt_idmap *, struct inode *, struct dentry *,
 int nfs_link(struct dentry *, struct inode *, struct dentry *);
 int nfs_mknod(struct mnt_idmap *, struct inode *, struct dentry *, umode_t,
 	      dev_t);
-int nfs_rename(struct user_namespace *, struct inode *, struct dentry *,
+int nfs_rename(struct mnt_idmap *, struct inode *, struct dentry *,
 	       struct inode *, struct dentry *, unsigned int);
 
 #ifdef CONFIG_NFS_V4_2

fs/nilfs2/namei.c

@@ -340,7 +340,7 @@ static int nilfs_rmdir(struct inode *dir, struct dentry *dentry)
 	return err;
 }
 
-static int nilfs_rename(struct user_namespace *mnt_userns,
+static int nilfs_rename(struct mnt_idmap *idmap,
 			struct inode *old_dir, struct dentry *old_dentry,
 			struct inode *new_dir, struct dentry *new_dentry,
 			unsigned int flags)