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, 19 insertions, 12 deletions

diff --git a/fs/nilfs2/inode.c b/fs/nilfs2/inode.c
index 8aad3c48092a..2e8eb263cf0f 100644
--- a/fs/nilfs2/inode.c
+++ b/fs/nilfs2/inode.c
@@ -805,7 +805,8 @@ void nilfs_evict_inode(struct inode *inode)
 	 */
 }
 
-int nilfs_setattr(struct dentry *dentry, struct iattr *iattr)
+int nilfs_setattr(struct user_namespace *mnt_userns, struct dentry *dentry,
+		  struct iattr *iattr)
 {
 	struct nilfs_transaction_info ti;
 	struct inode *inode = d_inode(dentry);
@@ -843,7 +844,8 @@ out_err:
 	return err;
 }
 
-int nilfs_permission(struct inode *inode, int mask)
+int nilfs_permission(struct user_namespace *mnt_userns, struct inode *inode,
+		     int mask)
 {
 	struct nilfs_root *root = NILFS_I(inode)->i_root;
 
diff --git a/fs/nilfs2/namei.c b/fs/nilfs2/namei.c
index a6ec7961d4f5..ecace5f96a95 100644
--- a/fs/nilfs2/namei.c
+++ b/fs/nilfs2/namei.c
@@ -72,8 +72,8 @@ nilfs_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
  * If the create succeeds, we fill in the inode information
  * with d_instantiate().
  */
-static int nilfs_create(struct inode *dir, struct dentry *dentry, umode_t mode,
-			bool excl)
+static int nilfs_create(struct user_namespace *mnt_userns, struct inode *dir,
+			struct dentry *dentry, umode_t mode, bool excl)
 {
 	struct inode *inode;
 	struct nilfs_transaction_info ti;
@@ -100,7 +100,8 @@ static int nilfs_create(struct inode *dir, struct dentry *dentry, umode_t mode,
 }
 
 static int
-nilfs_mknod(struct inode *dir, struct dentry *dentry, umode_t mode, dev_t rdev)
+nilfs_mknod(struct user_namespace *mnt_userns, struct inode *dir,
+	    struct dentry *dentry, umode_t mode, dev_t rdev)
 {
 	struct inode *inode;
 	struct nilfs_transaction_info ti;
@@ -124,8 +125,8 @@ nilfs_mknod(struct inode *dir, struct dentry *dentry, umode_t mode, dev_t rdev)
 	return err;
 }
 
-static int nilfs_symlink(struct inode *dir, struct dentry *dentry,
-			 const char *symname)
+static int nilfs_symlink(struct user_namespace *mnt_userns, struct inode *dir,
+			 struct dentry *dentry, const char *symname)
 {
 	struct nilfs_transaction_info ti;
 	struct super_block *sb = dir->i_sb;
@@ -201,7 +202,8 @@ static int nilfs_link(struct dentry *old_dentry, struct inode *dir,
 	return err;
 }
 
-static int nilfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
+static int nilfs_mkdir(struct user_namespace *mnt_userns, struct inode *dir,
+		       struct dentry *dentry, umode_t mode)
 {
 	struct inode *inode;
 	struct nilfs_transaction_info ti;
@@ -338,8 +340,9 @@ static int nilfs_rmdir(struct inode *dir, struct dentry *dentry)
 	return err;
 }
 
-static int nilfs_rename(struct inode *old_dir, struct dentry *old_dentry,
-			struct inode *new_dir,	struct dentry *new_dentry,
+static int nilfs_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);
diff --git a/fs/nilfs2/nilfs.h b/fs/nilfs2/nilfs.h
index f8450ee3fd06..c4a45a081ade 100644
--- a/fs/nilfs2/nilfs.h
+++ b/fs/nilfs2/nilfs.h
@@ -267,9 +267,11 @@ extern struct inode *nilfs_iget_for_gc(struct super_block *sb,
 extern void nilfs_update_inode(struct inode *, struct buffer_head *, int);
 extern void nilfs_truncate(struct inode *);
 extern void nilfs_evict_inode(struct inode *);
-extern int nilfs_setattr(struct dentry *, struct iattr *);
+extern int nilfs_setattr(struct user_namespace *, struct dentry *,
+			 struct iattr *);
 extern void nilfs_write_failed(struct address_space *mapping, loff_t to);
-int nilfs_permission(struct inode *inode, int mask);
+int nilfs_permission(struct user_namespace *mnt_userns, struct inode *inode,
+		     int mask);
 int nilfs_load_inode_block(struct inode *inode, struct buffer_head **pbh);
 extern int nilfs_inode_dirty(struct inode *);
 int nilfs_set_file_dirty(struct inode *inode, unsigned int nr_dirty);