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, 22 insertions, 14 deletions

diff --git a/fs/bad_inode.c b/fs/bad_inode.c
index 54f0ce444272..48e16144c1f7 100644
--- a/fs/bad_inode.c
+++ b/fs/bad_inode.c
@@ -27,8 +27,9 @@ static const struct file_operations bad_file_ops =
 	.open		= bad_file_open,
 };
 
-static int bad_inode_create (struct inode *dir, struct dentry *dentry,
-		umode_t mode, bool excl)
+static int bad_inode_create(struct user_namespace *mnt_userns,
+			    struct inode *dir, struct dentry *dentry,
+			    umode_t mode, bool excl)
 {
 	return -EIO;
 }
@@ -50,14 +51,15 @@ static int bad_inode_unlink(struct inode *dir, struct dentry *dentry)
 	return -EIO;
 }
 
-static int bad_inode_symlink (struct inode *dir, struct dentry *dentry,
-		const char *symname)
+static int bad_inode_symlink(struct user_namespace *mnt_userns,
+			     struct inode *dir, struct dentry *dentry,
+			     const char *symname)
 {
 	return -EIO;
 }
 
-static int bad_inode_mkdir(struct inode *dir, struct dentry *dentry,
-			umode_t mode)
+static int bad_inode_mkdir(struct user_namespace *mnt_userns, struct inode *dir,
+			   struct dentry *dentry, umode_t mode)
 {
 	return -EIO;
 }
@@ -67,13 +69,14 @@ static int bad_inode_rmdir (struct inode *dir, struct dentry *dentry)
 	return -EIO;
 }
 
-static int bad_inode_mknod (struct inode *dir, struct dentry *dentry,
-			umode_t mode, dev_t rdev)
+static int bad_inode_mknod(struct user_namespace *mnt_userns, struct inode *dir,
+			   struct dentry *dentry, umode_t mode, dev_t rdev)
 {
 	return -EIO;
 }
 
-static int bad_inode_rename2(struct inode *old_dir, struct dentry *old_dentry,
+static int bad_inode_rename2(struct user_namespace *mnt_userns,
+			     struct inode *old_dir, struct dentry *old_dentry,
 			     struct inode *new_dir, struct dentry *new_dentry,
 			     unsigned int flags)
 {
@@ -86,18 +89,21 @@ static int bad_inode_readlink(struct dentry *dentry, char __user *buffer,
 	return -EIO;
 }
 
-static int bad_inode_permission(struct inode *inode, int mask)
+static int bad_inode_permission(struct user_namespace *mnt_userns,
+				struct inode *inode, int mask)
 {
 	return -EIO;
 }
 
-static int bad_inode_getattr(const struct path *path, struct kstat *stat,
+static int bad_inode_getattr(struct user_namespace *mnt_userns,
+			     const struct path *path, struct kstat *stat,
 			     u32 request_mask, unsigned int query_flags)
 {
 	return -EIO;
 }
 
-static int bad_inode_setattr(struct dentry *direntry, struct iattr *attrs)
+static int bad_inode_setattr(struct user_namespace *mnt_userns,
+			     struct dentry *direntry, struct iattr *attrs)
 {
 	return -EIO;
 }
@@ -140,13 +146,15 @@ static int bad_inode_atomic_open(struct inode *inode, struct dentry *dentry,
 	return -EIO;
 }
 
-static int bad_inode_tmpfile(struct inode *inode, struct dentry *dentry,
+static int bad_inode_tmpfile(struct user_namespace *mnt_userns,
+			     struct inode *inode, struct dentry *dentry,
 			     umode_t mode)
 {
 	return -EIO;
 }
 
-static int bad_inode_set_acl(struct inode *inode, struct posix_acl *acl,
+static int bad_inode_set_acl(struct user_namespace *mnt_userns,
+			     struct inode *inode, struct posix_acl *acl,
 			     int type)
 {
 	return -EIO;