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, 4 insertions, 3 deletions

diff --git a/fs/afs/inode.c b/fs/afs/inode.c
index 795ee5cb3817..1156b2df28d3 100644
--- a/fs/afs/inode.c
+++ b/fs/afs/inode.c
@@ -734,8 +734,8 @@ error_unlock:
 /*
  * read the attributes of an inode
  */
-int afs_getattr(const struct path *path, struct kstat *stat,
-		u32 request_mask, unsigned int query_flags)
+int afs_getattr(struct user_namespace *mnt_userns, const struct path *path,
+		struct kstat *stat, u32 request_mask, unsigned int query_flags)
 {
 	struct inode *inode = d_inode(path->dentry);
 	struct afs_vnode *vnode = AFS_FS_I(inode);
@@ -857,7 +857,8 @@ static const struct afs_operation_ops afs_setattr_operation = {
 /*
  * set the attributes of an inode
  */
-int afs_setattr(struct dentry *dentry, struct iattr *attr)
+int afs_setattr(struct user_namespace *mnt_userns, struct dentry *dentry,
+		struct iattr *attr)
 {
 	struct afs_operation *op;
 	struct afs_vnode *vnode = AFS_FS_I(d_inode(dentry));