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/hpfs/hpfs_fn.h b/fs/hpfs/hpfs_fn.h
index 1cca83218fb5..167ec6884642 100644
--- a/fs/hpfs/hpfs_fn.h
+++ b/fs/hpfs/hpfs_fn.h
@@ -280,7 +280,7 @@ void hpfs_init_inode(struct inode *);
 void hpfs_read_inode(struct inode *);
 void hpfs_write_inode(struct inode *);
 void hpfs_write_inode_nolock(struct inode *);
-int hpfs_setattr(struct dentry *, struct iattr *);
+int hpfs_setattr(struct user_namespace *, struct dentry *, struct iattr *);
 void hpfs_write_if_changed(struct inode *);
 void hpfs_evict_inode(struct inode *);
 
diff --git a/fs/hpfs/inode.c b/fs/hpfs/inode.c
index 8ba2152a78ba..82208cc28ebd 100644
--- a/fs/hpfs/inode.c
+++ b/fs/hpfs/inode.c
@@ -257,7 +257,8 @@ void hpfs_write_inode_nolock(struct inode *i)
 	brelse(bh);
 }
 
-int hpfs_setattr(struct dentry *dentry, struct iattr *attr)
+int hpfs_setattr(struct user_namespace *mnt_userns, struct dentry *dentry,
+		 struct iattr *attr)
 {
 	struct inode *inode = d_inode(dentry);
 	int error = -EINVAL;
diff --git a/fs/hpfs/namei.c b/fs/hpfs/namei.c
index 1aee39160ac5..d73f8a67168e 100644
--- a/fs/hpfs/namei.c
+++ b/fs/hpfs/namei.c
@@ -20,7 +20,8 @@ static void hpfs_update_directory_times(struct inode *dir)
 	hpfs_write_inode_nolock(dir);
 }
 
-static int hpfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
+static int hpfs_mkdir(struct user_namespace *mnt_userns, struct inode *dir,
+		      struct dentry *dentry, umode_t mode)
 {
 	const unsigned char *name = dentry->d_name.name;
 	unsigned len = dentry->d_name.len;
@@ -128,7 +129,8 @@ bail:
 	return err;
 }
 
-static int hpfs_create(struct inode *dir, struct dentry *dentry, umode_t mode, bool excl)
+static int hpfs_create(struct user_namespace *mnt_userns, struct inode *dir,
+		       struct dentry *dentry, umode_t mode, bool excl)
 {
 	const unsigned char *name = dentry->d_name.name;
 	unsigned len = dentry->d_name.len;
@@ -215,7 +217,8 @@ bail:
 	return err;
 }
 
-static int hpfs_mknod(struct inode *dir, struct dentry *dentry, umode_t mode, dev_t rdev)
+static int hpfs_mknod(struct user_namespace *mnt_userns, struct inode *dir,
+		      struct dentry *dentry, umode_t mode, dev_t rdev)
 {
 	const unsigned char *name = dentry->d_name.name;
 	unsigned len = dentry->d_name.len;
@@ -289,7 +292,8 @@ bail:
 	return err;
 }
 
-static int hpfs_symlink(struct inode *dir, struct dentry *dentry, const char *symlink)
+static int hpfs_symlink(struct user_namespace *mnt_userns, struct inode *dir,
+			struct dentry *dentry, const char *symlink)
 {
 	const unsigned char *name = dentry->d_name.name;
 	unsigned len = dentry->d_name.len;
@@ -506,10 +510,10 @@ fail:
 const struct address_space_operations hpfs_symlink_aops = {
 	.readpage	= hpfs_symlink_readpage
 };
-	
-static int hpfs_rename(struct inode *old_dir, struct dentry *old_dentry,
-		       struct inode *new_dir, struct dentry *new_dentry,
-		       unsigned int flags)
+
+static int hpfs_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)
 {
 	const unsigned char *old_name = old_dentry->d_name.name;
 	unsigned old_len = old_dentry->d_name.len;