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>

3 files changed, 15 insertions, 10 deletions

diff --git a/fs/ufs/inode.c b/fs/ufs/inode.c
index 6b51f3b20143..debc282c1bb4 100644
--- a/fs/ufs/inode.c
+++ b/fs/ufs/inode.c
@@ -1211,7 +1211,8 @@ out:
 	return err;
 }
 
-int ufs_setattr(struct dentry *dentry, struct iattr *attr)
+int ufs_setattr(struct user_namespace *mnt_userns, struct dentry *dentry,
+		struct iattr *attr)
 {
 	struct inode *inode = d_inode(dentry);
 	unsigned int ia_valid = attr->ia_valid;
diff --git a/fs/ufs/namei.c b/fs/ufs/namei.c
index 9ef40f100415..29d5a0e0c8f0 100644
--- a/fs/ufs/namei.c
+++ b/fs/ufs/namei.c
@@ -69,7 +69,8 @@ static struct dentry *ufs_lookup(struct inode * dir, struct dentry *dentry, unsi
  * If the create succeeds, we fill in the inode information
  * with d_instantiate(). 
  */
-static int ufs_create (struct inode * dir, struct dentry * dentry, umode_t mode,
+static int ufs_create (struct user_namespace * mnt_userns,
+		struct inode * dir, struct dentry * dentry, umode_t mode,
 		bool excl)
 {
 	struct inode *inode;
@@ -85,7 +86,8 @@ static int ufs_create (struct inode * dir, struct dentry * dentry, umode_t mode,
 	return ufs_add_nondir(dentry, inode);
 }
 
-static int ufs_mknod(struct inode *dir, struct dentry *dentry, umode_t mode, dev_t rdev)
+static int ufs_mknod(struct user_namespace *mnt_userns, struct inode *dir,
+		     struct dentry *dentry, umode_t mode, dev_t rdev)
 {
 	struct inode *inode;
 	int err;
@@ -104,8 +106,8 @@ static int ufs_mknod(struct inode *dir, struct dentry *dentry, umode_t mode, dev
 	return err;
 }
 
-static int ufs_symlink (struct inode * dir, struct dentry * dentry,
-	const char * symname)
+static int ufs_symlink (struct user_namespace * mnt_userns, struct inode * dir,
+	struct dentry * dentry, const char * symname)
 {
 	struct super_block * sb = dir->i_sb;
 	int err;
@@ -164,7 +166,8 @@ static int ufs_link (struct dentry * old_dentry, struct inode * dir,
 	return error;
 }
 
-static int ufs_mkdir(struct inode * dir, struct dentry * dentry, umode_t mode)
+static int ufs_mkdir(struct user_namespace * mnt_userns, struct inode * dir,
+	struct dentry * dentry, umode_t mode)
 {
 	struct inode * inode;
 	int err;
@@ -240,9 +243,9 @@ static int ufs_rmdir (struct inode * dir, struct dentry *dentry)
 	return err;
 }
 
-static int ufs_rename(struct inode *old_dir, struct dentry *old_dentry,
-		      struct inode *new_dir, struct dentry *new_dentry,
-		      unsigned int flags)
+static int ufs_rename(struct user_namespace *mnt_userns, struct inode *old_dir,
+		      struct dentry *old_dentry, struct inode *new_dir,
+		      struct dentry *new_dentry, unsigned int flags)
 {
 	struct inode *old_inode = d_inode(old_dentry);
 	struct inode *new_inode = d_inode(new_dentry);
diff --git a/fs/ufs/ufs.h b/fs/ufs/ufs.h
index b49e0efdf3d7..550f7c5a3636 100644
--- a/fs/ufs/ufs.h
+++ b/fs/ufs/ufs.h
@@ -123,7 +123,8 @@ extern struct inode *ufs_iget(struct super_block *, unsigned long);
 extern int ufs_write_inode (struct inode *, struct writeback_control *);
 extern int ufs_sync_inode (struct inode *);
 extern void ufs_evict_inode (struct inode *);
-extern int ufs_setattr(struct dentry *dentry, struct iattr *attr);
+extern int ufs_setattr(struct user_namespace *mnt_userns, struct dentry *dentry,
+		       struct iattr *attr);
 
 /* namei.c */
 extern const struct file_operations ufs_dir_operations;