fs: port ->symlink() 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>
diff --git a/Documentation/filesystems/locking.rst b/Documentation/filesystems/locking.rst
index 7783085..2e656b6 100644
--- a/Documentation/filesystems/locking.rst
+++ b/Documentation/filesystems/locking.rst
@@ -60,7 +60,7 @@
 	struct dentry * (*lookup) (struct inode *,struct dentry *, unsigned int);
 	int (*link) (struct dentry *,struct inode *,struct dentry *);
 	int (*unlink) (struct inode *,struct dentry *);
-	int (*symlink) (struct inode *,struct dentry *,const char *);
+	int (*symlink) (struct mnt_idmap *, struct inode *,struct dentry *,const char *);
 	int (*mkdir) (struct inode *,struct dentry *,umode_t);
 	int (*rmdir) (struct inode *,struct dentry *);
 	int (*mknod) (struct inode *,struct dentry *,umode_t,dev_t);
diff --git a/Documentation/filesystems/vfs.rst b/Documentation/filesystems/vfs.rst
index 6cf8d7d..5a1195c 100644
--- a/Documentation/filesystems/vfs.rst
+++ b/Documentation/filesystems/vfs.rst
@@ -425,7 +425,7 @@
 		struct dentry * (*lookup) (struct inode *,struct dentry *, unsigned int);
 		int (*link) (struct dentry *,struct inode *,struct dentry *);
 		int (*unlink) (struct inode *,struct dentry *);
-		int (*symlink) (struct user_namespace *, struct inode *,struct dentry *,const char *);
+		int (*symlink) (struct mnt_idmap *, struct inode *,struct dentry *,const char *);
 		int (*mkdir) (struct user_namespace *, 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);
diff --git a/fs/9p/vfs_inode.c b/fs/9p/vfs_inode.c
index 693afb6..401c0b6 100644
--- a/fs/9p/vfs_inode.c
+++ b/fs/9p/vfs_inode.c
@@ -1300,7 +1300,7 @@ static int v9fs_vfs_mkspecial(struct inode *dir, struct dentry *dentry,
 
 /**
  * v9fs_vfs_symlink - helper function to create symlinks
- * @mnt_userns: The user namespace of the mount
+ * @idmap: idmap of the mount
  * @dir: directory inode containing symlink
  * @dentry: dentry for symlink
  * @symname: symlink data
@@ -1310,7 +1310,7 @@ static int v9fs_vfs_mkspecial(struct inode *dir, struct dentry *dentry,
  */
 
 static int
-v9fs_vfs_symlink(struct user_namespace *mnt_userns, struct inode *dir,
+v9fs_vfs_symlink(struct mnt_idmap *idmap, struct inode *dir,
 		 struct dentry *dentry, const char *symname)
 {
 	p9_debug(P9_DEBUG_VFS, " %lu,%pd,%s\n",
diff --git a/fs/9p/vfs_inode_dotl.c b/fs/9p/vfs_inode_dotl.c
index 6f651d5..d324522 100644
--- a/fs/9p/vfs_inode_dotl.c
+++ b/fs/9p/vfs_inode_dotl.c
@@ -688,7 +688,7 @@ v9fs_stat2inode_dotl(struct p9_stat_dotl *stat, struct inode *inode,
 }
 
 static int
-v9fs_vfs_symlink_dotl(struct user_namespace *mnt_userns, struct inode *dir,
+v9fs_vfs_symlink_dotl(struct mnt_idmap *idmap, struct inode *dir,
 		      struct dentry *dentry, const char *symname)
 {
 	int err;
diff --git a/fs/affs/affs.h b/fs/affs/affs.h
index 31a56a4..f9f986a 100644
--- a/fs/affs/affs.h
+++ b/fs/affs/affs.h
@@ -174,7 +174,7 @@ extern int	affs_mkdir(struct user_namespace *mnt_userns, struct inode *dir,
 extern int	affs_rmdir(struct inode *dir, struct dentry *dentry);
 extern int	affs_link(struct dentry *olddentry, struct inode *dir,
 			  struct dentry *dentry);
-extern int	affs_symlink(struct user_namespace *mnt_userns,
+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,
diff --git a/fs/affs/namei.c b/fs/affs/namei.c
index 661852c..1d7f723 100644
--- a/fs/affs/namei.c
+++ b/fs/affs/namei.c
@@ -313,7 +313,7 @@ affs_rmdir(struct inode *dir, struct dentry *dentry)
 }
 
 int
-affs_symlink(struct user_namespace *mnt_userns, struct inode *dir,
+affs_symlink(struct mnt_idmap *idmap, struct inode *dir,
 	     struct dentry *dentry, const char *symname)
 {
 	struct super_block	*sb = dir->i_sb;
diff --git a/fs/afs/dir.c b/fs/afs/dir.c
index a70495f..a936aa8 100644
--- a/fs/afs/dir.c
+++ b/fs/afs/dir.c
@@ -36,7 +36,7 @@ static int afs_rmdir(struct inode *dir, struct dentry *dentry);
 static int afs_unlink(struct inode *dir, struct dentry *dentry);
 static int afs_link(struct dentry *from, struct inode *dir,
 		    struct dentry *dentry);
-static int afs_symlink(struct user_namespace *mnt_userns, struct inode *dir,
+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,
 		      struct dentry *old_dentry, struct inode *new_dir,
@@ -1760,7 +1760,7 @@ static const struct afs_operation_ops afs_symlink_operation = {
 /*
  * create a symlink in an AFS filesystem
  */
-static int afs_symlink(struct user_namespace *mnt_userns, struct inode *dir,
+static int afs_symlink(struct mnt_idmap *idmap, struct inode *dir,
 		       struct dentry *dentry, const char *content)
 {
 	struct afs_operation *op;
diff --git a/fs/autofs/root.c b/fs/autofs/root.c
index ca03c1c..bf0029c 100644
--- a/fs/autofs/root.c
+++ b/fs/autofs/root.c
@@ -11,7 +11,7 @@
 #include "autofs_i.h"
 
 static int autofs_dir_permission(struct user_namespace *, struct inode *, int);
-static int autofs_dir_symlink(struct user_namespace *, struct inode *,
+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 *);
@@ -563,7 +563,7 @@ static int autofs_dir_permission(struct user_namespace *mnt_userns,
 	return generic_permission(mnt_userns, inode, mask);
 }
 
-static int autofs_dir_symlink(struct user_namespace *mnt_userns,
+static int autofs_dir_symlink(struct mnt_idmap *idmap,
 			      struct inode *dir, struct dentry *dentry,
 			      const char *symname)
 {
diff --git a/fs/bad_inode.c b/fs/bad_inode.c
index 8712fc1..2d3ca4b 100644
--- a/fs/bad_inode.c
+++ b/fs/bad_inode.c
@@ -51,7 +51,7 @@ static int bad_inode_unlink(struct inode *dir, struct dentry *dentry)
 	return -EIO;
 }
 
-static int bad_inode_symlink(struct user_namespace *mnt_userns,
+static int bad_inode_symlink(struct mnt_idmap *idmap,
 			     struct inode *dir, struct dentry *dentry,
 			     const char *symname)
 {
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 3621e9a..f4879dd 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -9758,9 +9758,10 @@ int btrfs_start_delalloc_roots(struct btrfs_fs_info *fs_info, long nr,
 	return ret;
 }
 
-static int btrfs_symlink(struct user_namespace *mnt_userns, struct inode *dir,
+static int btrfs_symlink(struct mnt_idmap *idmap, struct inode *dir,
 			 struct dentry *dentry, const char *symname)
 {
+	struct user_namespace *mnt_userns = mnt_idmap_owner(idmap);
 	struct btrfs_fs_info *fs_info = btrfs_sb(dir->i_sb);
 	struct btrfs_trans_handle *trans;
 	struct btrfs_root *root = BTRFS_I(dir)->root;
diff --git a/fs/ceph/dir.c b/fs/ceph/dir.c
index cf4f70e..114375e 100644
--- a/fs/ceph/dir.c
+++ b/fs/ceph/dir.c
@@ -912,7 +912,7 @@ static int ceph_create(struct mnt_idmap *idmap, struct inode *dir,
 	return ceph_mknod(mnt_userns, dir, dentry, mode, 0);
 }
 
-static int ceph_symlink(struct user_namespace *mnt_userns, struct inode *dir,
+static int ceph_symlink(struct mnt_idmap *idmap, struct inode *dir,
 			struct dentry *dentry, const char *dest)
 {
 	struct ceph_mds_client *mdsc = ceph_sb_to_mdsc(dir->i_sb);
diff --git a/fs/cifs/cifsfs.h b/fs/cifs/cifsfs.h
index 0d4b3bf..52256b7 100644
--- a/fs/cifs/cifsfs.h
+++ b/fs/cifs/cifsfs.h
@@ -124,7 +124,7 @@ extern struct vfsmount *cifs_dfs_d_automount(struct path *path);
 /* Functions related to symlinks */
 extern const char *cifs_get_link(struct dentry *, struct inode *,
 			struct delayed_call *);
-extern int cifs_symlink(struct user_namespace *mnt_userns, struct inode *inode,
+extern int cifs_symlink(struct mnt_idmap *idmap, struct inode *inode,
 			struct dentry *direntry, const char *symname);
 
 #ifdef CONFIG_CIFS_XATTR
diff --git a/fs/cifs/link.c b/fs/cifs/link.c
index bd374fe..0ff9eab 100644
--- a/fs/cifs/link.c
+++ b/fs/cifs/link.c
@@ -568,7 +568,7 @@ cifs_hardlink(struct dentry *old_file, struct inode *inode,
 }
 
 int
-cifs_symlink(struct user_namespace *mnt_userns, struct inode *inode,
+cifs_symlink(struct mnt_idmap *idmap, struct inode *inode,
 	     struct dentry *direntry, const char *symname)
 {
 	int rc = -EOPNOTSUPP;
diff --git a/fs/coda/dir.c b/fs/coda/dir.c
index 480bca1..b8e82bc 100644
--- a/fs/coda/dir.c
+++ b/fs/coda/dir.c
@@ -228,7 +228,7 @@ static int coda_link(struct dentry *source_de, struct inode *dir_inode,
 }
 
 
-static int coda_symlink(struct user_namespace *mnt_userns,
+static int coda_symlink(struct mnt_idmap *idmap,
 			struct inode *dir_inode, struct dentry *de,
 			const char *symname)
 {
diff --git a/fs/configfs/configfs_internal.h b/fs/configfs/configfs_internal.h
index a94493e..e710a17 100644
--- a/fs/configfs/configfs_internal.h
+++ b/fs/configfs/configfs_internal.h
@@ -91,7 +91,7 @@ extern const struct inode_operations configfs_root_inode_operations;
 extern const struct inode_operations configfs_symlink_inode_operations;
 extern const struct dentry_operations configfs_dentry_ops;
 
-extern int configfs_symlink(struct user_namespace *mnt_userns,
+extern int configfs_symlink(struct mnt_idmap *idmap,
 			    struct inode *dir, struct dentry *dentry,
 			    const char *symname);
 extern int configfs_unlink(struct inode *dir, struct dentry *dentry);
diff --git a/fs/configfs/symlink.c b/fs/configfs/symlink.c
index 0623c3e..91db306 100644
--- a/fs/configfs/symlink.c
+++ b/fs/configfs/symlink.c
@@ -137,7 +137,7 @@ static int get_target(const char *symname, struct path *path,
 }
 
 
-int configfs_symlink(struct user_namespace *mnt_userns, struct inode *dir,
+int configfs_symlink(struct mnt_idmap *idmap, struct inode *dir,
 		     struct dentry *dentry, const char *symname)
 {
 	int ret;
diff --git a/fs/ecryptfs/inode.c b/fs/ecryptfs/inode.c
index afc49ab..692320e 100644
--- a/fs/ecryptfs/inode.c
+++ b/fs/ecryptfs/inode.c
@@ -456,7 +456,7 @@ static int ecryptfs_unlink(struct inode *dir, struct dentry *dentry)
 	return ecryptfs_do_unlink(dir, dentry, d_inode(dentry));
 }
 
-static int ecryptfs_symlink(struct user_namespace *mnt_userns,
+static int ecryptfs_symlink(struct mnt_idmap *idmap,
 			    struct inode *dir, struct dentry *dentry,
 			    const char *symname)
 {
diff --git a/fs/ext2/namei.c b/fs/ext2/namei.c
index 1d4d807..72d9a31 100644
--- a/fs/ext2/namei.c
+++ b/fs/ext2/namei.c
@@ -154,7 +154,7 @@ static int ext2_mknod (struct user_namespace * mnt_userns, struct inode * dir,
 	return err;
 }
 
-static int ext2_symlink (struct user_namespace * mnt_userns, struct inode * dir,
+static int ext2_symlink (struct mnt_idmap * idmap, struct inode * dir,
 	struct dentry * dentry, const char * symname)
 {
 	struct super_block * sb = dir->i_sb;
diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
index 0bb43e4..11d9c1d 100644
--- a/fs/ext4/namei.c
+++ b/fs/ext4/namei.c
@@ -3340,9 +3340,10 @@ static int ext4_init_symlink_block(handle_t *handle, struct inode *inode,
 	return err;
 }
 
-static int ext4_symlink(struct user_namespace *mnt_userns, struct inode *dir,
+static int ext4_symlink(struct mnt_idmap *idmap, struct inode *dir,
 			struct dentry *dentry, const char *symname)
 {
+	struct user_namespace *mnt_userns = mnt_idmap_owner(idmap);
 	handle_t *handle;
 	struct inode *inode;
 	int err, len = strlen(symname);
diff --git a/fs/f2fs/namei.c b/fs/f2fs/namei.c
index aacf4e2..5ef5ed5 100644
--- a/fs/f2fs/namei.c
+++ b/fs/f2fs/namei.c
@@ -660,9 +660,10 @@ static const char *f2fs_get_link(struct dentry *dentry,
 	return link;
 }
 
-static int f2fs_symlink(struct user_namespace *mnt_userns, struct inode *dir,
+static int f2fs_symlink(struct mnt_idmap *idmap, struct inode *dir,
 			struct dentry *dentry, const char *symname)
 {
+	struct user_namespace *mnt_userns = mnt_idmap_owner(idmap);
 	struct f2fs_sb_info *sbi = F2FS_I_SB(dir);
 	struct inode *inode;
 	size_t len = strlen(symname);
diff --git a/fs/fuse/dir.c b/fs/fuse/dir.c
index b748246..179d8a3 100644
--- a/fs/fuse/dir.c
+++ b/fs/fuse/dir.c
@@ -841,7 +841,7 @@ static int fuse_mkdir(struct user_namespace *mnt_userns, struct inode *dir,
 	return create_new_entry(fm, &args, dir, entry, S_IFDIR);
 }
 
-static int fuse_symlink(struct user_namespace *mnt_userns, struct inode *dir,
+static int fuse_symlink(struct mnt_idmap *idmap, struct inode *dir,
 			struct dentry *entry, const char *link)
 {
 	struct fuse_mount *fm = get_fuse_mount(dir);
diff --git a/fs/gfs2/inode.c b/fs/gfs2/inode.c
index f58b13a..8300497 100644
--- a/fs/gfs2/inode.c
+++ b/fs/gfs2/inode.c
@@ -1207,7 +1207,7 @@ static int gfs2_unlink(struct inode *dir, struct dentry *dentry)
 
 /**
  * gfs2_symlink - Create a symlink
- * @mnt_userns: User namespace of the mount the inode was found from
+ * @idmap: idmap of the mount the inode was found from
  * @dir: The directory to create the symlink in
  * @dentry: The dentry to put the symlink in
  * @symname: The thing which the link points to
@@ -1215,7 +1215,7 @@ static int gfs2_unlink(struct inode *dir, struct dentry *dentry)
  * Returns: errno
  */
 
-static int gfs2_symlink(struct user_namespace *mnt_userns, struct inode *dir,
+static int gfs2_symlink(struct mnt_idmap *idmap, struct inode *dir,
 			struct dentry *dentry, const char *symname)
 {
 	unsigned int size;
diff --git a/fs/hfsplus/dir.c b/fs/hfsplus/dir.c
index 2ce051f..36927ca 100644
--- a/fs/hfsplus/dir.c
+++ b/fs/hfsplus/dir.c
@@ -434,7 +434,7 @@ static int hfsplus_rmdir(struct inode *dir, struct dentry *dentry)
 	return res;
 }
 
-static int hfsplus_symlink(struct user_namespace *mnt_userns, struct inode *dir,
+static int hfsplus_symlink(struct mnt_idmap *idmap, struct inode *dir,
 			   struct dentry *dentry, const char *symname)
 {
 	struct hfsplus_sb_info *sbi = HFSPLUS_SB(dir->i_sb);
diff --git a/fs/hostfs/hostfs_kern.c b/fs/hostfs/hostfs_kern.c
index d617420..e78f53e 100644
--- a/fs/hostfs/hostfs_kern.c
+++ b/fs/hostfs/hostfs_kern.c
@@ -658,7 +658,7 @@ static int hostfs_unlink(struct inode *ino, struct dentry *dentry)
 	return err;
 }
 
-static int hostfs_symlink(struct user_namespace *mnt_userns, struct inode *ino,
+static int hostfs_symlink(struct mnt_idmap *idmap, struct inode *ino,
 			  struct dentry *dentry, const char *to)
 {
 	char *file;
diff --git a/fs/hpfs/namei.c b/fs/hpfs/namei.c
index f6cbd4a..c5f0aec 100644
--- a/fs/hpfs/namei.c
+++ b/fs/hpfs/namei.c
@@ -292,7 +292,7 @@ static int hpfs_mknod(struct user_namespace *mnt_userns, struct inode *dir,
 	return err;
 }
 
-static int hpfs_symlink(struct user_namespace *mnt_userns, struct inode *dir,
+static int hpfs_symlink(struct mnt_idmap *idmap, struct inode *dir,
 			struct dentry *dentry, const char *symlink)
 {
 	const unsigned char *name = dentry->d_name.name;
diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c
index 7ffcf4b..170c99c 100644
--- a/fs/hugetlbfs/inode.c
+++ b/fs/hugetlbfs/inode.c
@@ -1064,7 +1064,7 @@ static int hugetlbfs_tmpfile(struct user_namespace *mnt_userns,
 	return finish_open_simple(file, 0);
 }
 
-static int hugetlbfs_symlink(struct user_namespace *mnt_userns,
+static int hugetlbfs_symlink(struct mnt_idmap *idmap,
 			     struct inode *dir, struct dentry *dentry,
 			     const char *symname)
 {
diff --git a/fs/jffs2/dir.c b/fs/jffs2/dir.c
index 7494563..51433fe 100644
--- a/fs/jffs2/dir.c
+++ b/fs/jffs2/dir.c
@@ -30,7 +30,7 @@ static struct dentry *jffs2_lookup (struct inode *,struct dentry *,
 				    unsigned int);
 static int jffs2_link (struct dentry *,struct inode *,struct dentry *);
 static int jffs2_unlink (struct inode *,struct dentry *);
-static int jffs2_symlink (struct user_namespace *, struct inode *,
+static int jffs2_symlink (struct mnt_idmap *, struct inode *,
 			  struct dentry *, const char *);
 static int jffs2_mkdir (struct user_namespace *, struct inode *,struct dentry *,
 			umode_t);
@@ -279,7 +279,7 @@ static int jffs2_link (struct dentry *old_dentry, struct inode *dir_i, struct de
 
 /***********************************************************************/
 
-static int jffs2_symlink (struct user_namespace *mnt_userns, struct inode *dir_i,
+static int jffs2_symlink (struct mnt_idmap *idmap, struct inode *dir_i,
 			  struct dentry *dentry, const char *target)
 {
 	struct jffs2_inode_info *f, *dir_f;
diff --git a/fs/jfs/namei.c b/fs/jfs/namei.c
index 9d06479..e7d6558 100644
--- a/fs/jfs/namei.c
+++ b/fs/jfs/namei.c
@@ -869,7 +869,7 @@ static int jfs_link(struct dentry *old_dentry,
  * an intermediate result whose length exceeds PATH_MAX [XPG4.2]
 */
 
-static int jfs_symlink(struct user_namespace *mnt_userns, struct inode *dip,
+static int jfs_symlink(struct mnt_idmap *idmap, struct inode *dip,
 		       struct dentry *dentry, const char *name)
 {
 	int rc;
diff --git a/fs/minix/namei.c b/fs/minix/namei.c
index b8621cf..0a07410 100644
--- a/fs/minix/namei.c
+++ b/fs/minix/namei.c
@@ -71,7 +71,7 @@ static int minix_create(struct mnt_idmap *idmap, struct inode *dir,
 	return minix_mknod(&init_user_ns, dir, dentry, mode, 0);
 }
 
-static int minix_symlink(struct user_namespace *mnt_userns, struct inode *dir,
+static int minix_symlink(struct mnt_idmap *idmap, struct inode *dir,
 			 struct dentry *dentry, const char *symname)
 {
 	int err = -ENAMETOOLONG;
diff --git a/fs/namei.c b/fs/namei.c
index f356719..24ad4a8 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -4394,8 +4394,9 @@ int vfs_symlink(struct mnt_idmap *idmap, struct inode *dir,
 		struct dentry *dentry, const char *oldname)
 {
 	struct user_namespace *mnt_userns = mnt_idmap_owner(idmap);
-	int error = may_create(mnt_userns, dir, dentry);
+	int error;
 
+	error = may_create(mnt_userns, dir, dentry);
 	if (error)
 		return error;
 
@@ -4406,7 +4407,7 @@ int vfs_symlink(struct mnt_idmap *idmap, struct inode *dir,
 	if (error)
 		return error;
 
-	error = dir->i_op->symlink(mnt_userns, dir, dentry, oldname);
+	error = dir->i_op->symlink(idmap, dir, dentry, oldname);
 	if (!error)
 		fsnotify_create(dir, dentry);
 	return error;
diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
index a54337c..5ae3ed4 100644
--- a/fs/nfs/dir.c
+++ b/fs/nfs/dir.c
@@ -2524,7 +2524,7 @@ EXPORT_SYMBOL_GPL(nfs_unlink);
  * now have a new file handle and can instantiate an in-core NFS inode
  * and move the raw page into its mapping.
  */
-int nfs_symlink(struct user_namespace *mnt_userns, struct inode *dir,
+int nfs_symlink(struct mnt_idmap *idmap, struct inode *dir,
 		struct dentry *dentry, const char *symname)
 {
 	struct page *page;
diff --git a/fs/nfs/internal.h b/fs/nfs/internal.h
index 988a155..33ec2c2 100644
--- a/fs/nfs/internal.h
+++ b/fs/nfs/internal.h
@@ -390,7 +390,7 @@ int nfs_mkdir(struct user_namespace *, struct inode *, struct dentry *,
 	      umode_t);
 int nfs_rmdir(struct inode *, struct dentry *);
 int nfs_unlink(struct inode *, struct dentry *);
-int nfs_symlink(struct user_namespace *, struct inode *, struct dentry *,
+int nfs_symlink(struct mnt_idmap *, struct inode *, struct dentry *,
 		const char *);
 int nfs_link(struct dentry *, struct inode *, struct dentry *);
 int nfs_mknod(struct user_namespace *, struct inode *, struct dentry *, umode_t,
diff --git a/fs/nilfs2/namei.c b/fs/nilfs2/namei.c
index 4be5d9d..d6cd71b 100644
--- a/fs/nilfs2/namei.c
+++ b/fs/nilfs2/namei.c
@@ -125,7 +125,7 @@ nilfs_mknod(struct user_namespace *mnt_userns, struct inode *dir,
 	return err;
 }
 
-static int nilfs_symlink(struct user_namespace *mnt_userns, struct inode *dir,
+static int nilfs_symlink(struct mnt_idmap *idmap, struct inode *dir,
 			 struct dentry *dentry, const char *symname)
 {
 	struct nilfs_transaction_info ti;
diff --git a/fs/ntfs3/namei.c b/fs/ntfs3/namei.c
index 8e46372..be6a00a 100644
--- a/fs/ntfs3/namei.c
+++ b/fs/ntfs3/namei.c
@@ -184,9 +184,10 @@ static int ntfs_unlink(struct inode *dir, struct dentry *dentry)
 /*
  * ntfs_symlink - inode_operations::symlink
  */
-static int ntfs_symlink(struct user_namespace *mnt_userns, struct inode *dir,
+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;
 
diff --git a/fs/ocfs2/namei.c b/fs/ocfs2/namei.c
index c931ddb..dedb37a 100644
--- a/fs/ocfs2/namei.c
+++ b/fs/ocfs2/namei.c
@@ -1784,7 +1784,7 @@ static int ocfs2_create_symlink_data(struct ocfs2_super *osb,
 	return status;
 }
 
-static int ocfs2_symlink(struct user_namespace *mnt_userns,
+static int ocfs2_symlink(struct mnt_idmap *idmap,
 			 struct inode *dir,
 			 struct dentry *dentry,
 			 const char *symname)
diff --git a/fs/orangefs/namei.c b/fs/orangefs/namei.c
index a47e73f..59866be 100644
--- a/fs/orangefs/namei.c
+++ b/fs/orangefs/namei.c
@@ -216,7 +216,7 @@ static int orangefs_unlink(struct inode *dir, struct dentry *dentry)
 	return ret;
 }
 
-static int orangefs_symlink(struct user_namespace *mnt_userns,
+static int orangefs_symlink(struct mnt_idmap *idmap,
 		         struct inode *dir,
 			 struct dentry *dentry,
 			 const char *symname)
diff --git a/fs/overlayfs/dir.c b/fs/overlayfs/dir.c
index fc37265..272906e 100644
--- a/fs/overlayfs/dir.c
+++ b/fs/overlayfs/dir.c
@@ -677,7 +677,7 @@ static int ovl_mknod(struct user_namespace *mnt_userns, struct inode *dir,
 	return ovl_create_object(dentry, mode, rdev, NULL);
 }
 
-static int ovl_symlink(struct user_namespace *mnt_userns, struct inode *dir,
+static int ovl_symlink(struct mnt_idmap *idmap, struct inode *dir,
 		       struct dentry *dentry, const char *link)
 {
 	return ovl_create_object(dentry, S_IFLNK, 0, link);
diff --git a/fs/ramfs/inode.c b/fs/ramfs/inode.c
index 77fd43f..f97b885 100644
--- a/fs/ramfs/inode.c
+++ b/fs/ramfs/inode.c
@@ -125,7 +125,7 @@ static int ramfs_create(struct mnt_idmap *idmap, struct inode *dir,
 	return ramfs_mknod(&init_user_ns, dir, dentry, mode | S_IFREG, 0);
 }
 
-static int ramfs_symlink(struct user_namespace *mnt_userns, struct inode *dir,
+static int ramfs_symlink(struct mnt_idmap *idmap, struct inode *dir,
 			 struct dentry *dentry, const char *symname)
 {
 	struct inode *inode;
diff --git a/fs/reiserfs/namei.c b/fs/reiserfs/namei.c
index c1b91a9..062e05f 100644
--- a/fs/reiserfs/namei.c
+++ b/fs/reiserfs/namei.c
@@ -1099,7 +1099,7 @@ static int reiserfs_unlink(struct inode *dir, struct dentry *dentry)
 	return retval;
 }
 
-static int reiserfs_symlink(struct user_namespace *mnt_userns,
+static int reiserfs_symlink(struct mnt_idmap *idmap,
 			    struct inode *parent_dir, struct dentry *dentry,
 			    const char *symname)
 {
diff --git a/fs/sysv/namei.c b/fs/sysv/namei.c
index f862fb8..c277c0a 100644
--- a/fs/sysv/namei.c
+++ b/fs/sysv/namei.c
@@ -67,7 +67,7 @@ static int sysv_create(struct mnt_idmap *idmap, struct inode *dir,
 	return sysv_mknod(&init_user_ns, dir, dentry, mode, 0);
 }
 
-static int sysv_symlink(struct user_namespace *mnt_userns, struct inode *dir,
+static int sysv_symlink(struct mnt_idmap *idmap, struct inode *dir,
 			struct dentry *dentry, const char *symname)
 {
 	int err = -ENAMETOOLONG;
diff --git a/fs/ubifs/dir.c b/fs/ubifs/dir.c
index 43a1d9c..325c569 100644
--- a/fs/ubifs/dir.c
+++ b/fs/ubifs/dir.c
@@ -1141,7 +1141,7 @@ static int ubifs_mknod(struct user_namespace *mnt_userns, struct inode *dir,
 	return err;
 }
 
-static int ubifs_symlink(struct user_namespace *mnt_userns, struct inode *dir,
+static int ubifs_symlink(struct mnt_idmap *idmap, struct inode *dir,
 			 struct dentry *dentry, const char *symname)
 {
 	struct inode *inode;
diff --git a/fs/udf/namei.c b/fs/udf/namei.c
index 91921a3..f2c3ee7 100644
--- a/fs/udf/namei.c
+++ b/fs/udf/namei.c
@@ -881,7 +881,7 @@ static int udf_unlink(struct inode *dir, struct dentry *dentry)
 	return retval;
 }
 
-static int udf_symlink(struct user_namespace *mnt_userns, struct inode *dir,
+static int udf_symlink(struct mnt_idmap *idmap, struct inode *dir,
 		       struct dentry *dentry, const char *symname)
 {
 	struct inode *inode = udf_new_inode(dir, S_IFLNK | 0777);
diff --git a/fs/ufs/namei.c b/fs/ufs/namei.c
index 6904ce95..cb3d9be 100644
--- a/fs/ufs/namei.c
+++ b/fs/ufs/namei.c
@@ -106,7 +106,7 @@ static int ufs_mknod(struct user_namespace *mnt_userns, struct inode *dir,
 	return err;
 }
 
-static int ufs_symlink (struct user_namespace * mnt_userns, struct inode * dir,
+static int ufs_symlink (struct mnt_idmap * idmap, struct inode * dir,
 	struct dentry * dentry, const char * symname)
 {
 	struct super_block * sb = dir->i_sb;
diff --git a/fs/vboxsf/dir.c b/fs/vboxsf/dir.c
index 0a9e76c..95d54cb 100644
--- a/fs/vboxsf/dir.c
+++ b/fs/vboxsf/dir.c
@@ -430,7 +430,7 @@ static int vboxsf_dir_rename(struct user_namespace *mnt_userns,
 	return err;
 }
 
-static int vboxsf_dir_symlink(struct user_namespace *mnt_userns,
+static int vboxsf_dir_symlink(struct mnt_idmap *idmap,
 			      struct inode *parent, struct dentry *dentry,
 			      const char *symname)
 {
diff --git a/fs/xfs/xfs_iops.c b/fs/xfs/xfs_iops.c
index 9690748..4f9fcd0 100644
--- a/fs/xfs/xfs_iops.c
+++ b/fs/xfs/xfs_iops.c
@@ -401,11 +401,12 @@ xfs_vn_unlink(
 
 STATIC int
 xfs_vn_symlink(
-	struct user_namespace	*mnt_userns,
+	struct mnt_idmap	*idmap,
 	struct inode		*dir,
 	struct dentry		*dentry,
 	const char		*symname)
 {
+	struct user_namespace	*mnt_userns = mnt_idmap_owner(idmap);
 	struct inode	*inode;
 	struct xfs_inode *cip = NULL;
 	struct xfs_name	name;
diff --git a/include/linux/fs.h b/include/linux/fs.h
index fddfacf..4bde68e 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -2143,7 +2143,7 @@ struct inode_operations {
 		       umode_t, bool);
 	int (*link) (struct dentry *,struct inode *,struct dentry *);
 	int (*unlink) (struct inode *,struct dentry *);
-	int (*symlink) (struct user_namespace *, 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);
diff --git a/kernel/bpf/inode.c b/kernel/bpf/inode.c
index 4f841e1..32c8f69 100644
--- a/kernel/bpf/inode.c
+++ b/kernel/bpf/inode.c
@@ -382,7 +382,7 @@ bpf_lookup(struct inode *dir, struct dentry *dentry, unsigned flags)
 	return simple_lookup(dir, dentry, flags);
 }
 
-static int bpf_symlink(struct user_namespace *mnt_userns, struct inode *dir,
+static int bpf_symlink(struct mnt_idmap *idmap, struct inode *dir,
 		       struct dentry *dentry, const char *target)
 {
 	char *link = kstrdup(target, GFP_USER | __GFP_NOWARN);
diff --git a/mm/shmem.c b/mm/shmem.c
index 8c29694..38b973f 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -3124,7 +3124,7 @@ static int shmem_rename2(struct user_namespace *mnt_userns,
 	return 0;
 }
 
-static int shmem_symlink(struct user_namespace *mnt_userns, struct inode *dir,
+static int shmem_symlink(struct mnt_idmap *idmap, struct inode *dir,
 			 struct dentry *dentry, const char *symname)
 {
 	int error;