fs: make helpers idmap mount aware

Extend some inode methods with an additional user namespace argument. A
filesystem that is aware of idmapped mounts will receive the user
namespace the mount has been marked with. This can be used for
additional permission checking and also to enable filesystems to
translate between uids and gids if they need to. We have implemented all
relevant helpers in earlier patches.

As requested we simply extend the exisiting inode method instead of
introducing new ones. This is a little more code churn but it's mostly
mechanical and doesnt't leave us with additional inode methods.

Link: https://lore.kernel.org/r/20210121131959.646623-25-christian.brauner@ubuntu.com
Cc: Christoph Hellwig <hch@lst.de>
Cc: David Howells <dhowells@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>

1 files changed, 20 insertions, 13 deletions

diff --git a/fs/jffs2/dir.c b/fs/jffs2/dir.c
index 776493713153..c0aabbcbfd58 100644
--- a/fs/jffs2/dir.c
+++ b/fs/jffs2/dir.c
@@ -24,18 +24,21 @@
 
 static int jffs2_readdir (struct file *, struct dir_context *);
 
-static int jffs2_create (struct inode *,struct dentry *,umode_t,
-			 bool);
+static int jffs2_create (struct user_namespace *, struct inode *,
+		         struct dentry *, umode_t, bool);
 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 inode *,struct dentry *,const char *);
-static int jffs2_mkdir (struct inode *,struct dentry *,umode_t);
+static int jffs2_symlink (struct user_namespace *, struct inode *,
+			  struct dentry *, const char *);
+static int jffs2_mkdir (struct user_namespace *, struct inode *,struct dentry *,
+			umode_t);
 static int jffs2_rmdir (struct inode *,struct dentry *);
-static int jffs2_mknod (struct inode *,struct dentry *,umode_t,dev_t);
-static int jffs2_rename (struct inode *, struct dentry *,
-			 struct inode *, struct dentry *,
+static int jffs2_mknod (struct user_namespace *, struct inode *,struct dentry *,
+			umode_t,dev_t);
+static int jffs2_rename (struct user_namespace *, struct inode *,
+			 struct dentry *, struct inode *, struct dentry *,
 			 unsigned int);
 
 const struct file_operations jffs2_dir_operations =
@@ -157,8 +160,8 @@ static int jffs2_readdir(struct file *file, struct dir_context *ctx)
 /***********************************************************************/
 
 
-static int jffs2_create(struct inode *dir_i, struct dentry *dentry,
-			umode_t mode, bool excl)
+static int jffs2_create(struct user_namespace *mnt_userns, struct inode *dir_i,
+			struct dentry *dentry, umode_t mode, bool excl)
 {
 	struct jffs2_raw_inode *ri;
 	struct jffs2_inode_info *f, *dir_f;
@@ -276,7 +279,8 @@ static int jffs2_link (struct dentry *old_dentry, struct inode *dir_i, struct de
 
 /***********************************************************************/
 
-static int jffs2_symlink (struct inode *dir_i, struct dentry *dentry, const char *target)
+static int jffs2_symlink (struct user_namespace *mnt_userns, struct inode *dir_i,
+			  struct dentry *dentry, const char *target)
 {
 	struct jffs2_inode_info *f, *dir_f;
 	struct jffs2_sb_info *c;
@@ -438,7 +442,8 @@ static int jffs2_symlink (struct inode *dir_i, struct dentry *dentry, const char
 }
 
 
-static int jffs2_mkdir (struct inode *dir_i, struct dentry *dentry, umode_t mode)
+static int jffs2_mkdir (struct user_namespace *mnt_userns, struct inode *dir_i,
+		        struct dentry *dentry, umode_t mode)
 {
 	struct jffs2_inode_info *f, *dir_f;
 	struct jffs2_sb_info *c;
@@ -609,7 +614,8 @@ static int jffs2_rmdir (struct inode *dir_i, struct dentry *dentry)
 	return ret;
 }
 
-static int jffs2_mknod (struct inode *dir_i, struct dentry *dentry, umode_t mode, dev_t rdev)
+static int jffs2_mknod (struct user_namespace *mnt_userns, struct inode *dir_i,
+		        struct dentry *dentry, umode_t mode, dev_t rdev)
 {
 	struct jffs2_inode_info *f, *dir_f;
 	struct jffs2_sb_info *c;
@@ -756,7 +762,8 @@ static int jffs2_mknod (struct inode *dir_i, struct dentry *dentry, umode_t mode
 	return ret;
 }
 
-static int jffs2_rename (struct inode *old_dir_i, struct dentry *old_dentry,
+static int jffs2_rename (struct user_namespace *mnt_userns,
+			 struct inode *old_dir_i, struct dentry *old_dentry,
 			 struct inode *new_dir_i, struct dentry *new_dentry,
 			 unsigned int flags)
 {