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, 34 insertions, 24 deletions

diff --git a/fs/xfs/xfs_acl.c b/fs/xfs/xfs_acl.c
index 368351298bd5..332e87153c6c 100644
--- a/fs/xfs/xfs_acl.c
+++ b/fs/xfs/xfs_acl.c
@@ -238,7 +238,8 @@ xfs_acl_set_mode(
 }
 
 int
-xfs_set_acl(struct inode *inode, struct posix_acl *acl, int type)
+xfs_set_acl(struct user_namespace *mnt_userns, struct inode *inode,
+	    struct posix_acl *acl, int type)
 {
 	umode_t mode;
 	bool set_mode = false;
diff --git a/fs/xfs/xfs_acl.h b/fs/xfs/xfs_acl.h
index c042c0868016..7bdb3a4ed798 100644
--- a/fs/xfs/xfs_acl.h
+++ b/fs/xfs/xfs_acl.h
@@ -11,7 +11,8 @@ struct posix_acl;
 
 #ifdef CONFIG_XFS_POSIX_ACL
 extern struct posix_acl *xfs_get_acl(struct inode *inode, int type);
-extern int xfs_set_acl(struct inode *inode, struct posix_acl *acl, int type);
+extern int xfs_set_acl(struct user_namespace *mnt_userns, struct inode *inode,
+		       struct posix_acl *acl, int type);
 extern int __xfs_set_acl(struct inode *inode, struct posix_acl *acl, int type);
 void xfs_forget_acl(struct inode *inode, const char *name);
 #else
diff --git a/fs/xfs/xfs_iops.c b/fs/xfs/xfs_iops.c
index 26d22edef741..f5dfa128af64 100644
--- a/fs/xfs/xfs_iops.c
+++ b/fs/xfs/xfs_iops.c
@@ -220,29 +220,32 @@ xfs_generic_create(
 
 STATIC int
 xfs_vn_mknod(
-	struct inode	*dir,
-	struct dentry	*dentry,
-	umode_t		mode,
-	dev_t		rdev)
+	struct user_namespace	*mnt_userns,
+	struct inode		*dir,
+	struct dentry		*dentry,
+	umode_t			mode,
+	dev_t			rdev)
 {
 	return xfs_generic_create(dir, dentry, mode, rdev, false);
 }
 
 STATIC int
 xfs_vn_create(
-	struct inode	*dir,
-	struct dentry	*dentry,
-	umode_t		mode,
-	bool		flags)
+	struct user_namespace	*mnt_userns,
+	struct inode		*dir,
+	struct dentry		*dentry,
+	umode_t			mode,
+	bool			flags)
 {
 	return xfs_generic_create(dir, dentry, mode, 0, false);
 }
 
 STATIC int
 xfs_vn_mkdir(
-	struct inode	*dir,
-	struct dentry	*dentry,
-	umode_t		mode)
+	struct user_namespace	*mnt_userns,
+	struct inode		*dir,
+	struct dentry		*dentry,
+	umode_t			mode)
 {
 	return xfs_generic_create(dir, dentry, mode | S_IFDIR, 0, false);
 }
@@ -361,9 +364,10 @@ xfs_vn_unlink(
 
 STATIC int
 xfs_vn_symlink(
-	struct inode	*dir,
-	struct dentry	*dentry,
-	const char	*symname)
+	struct user_namespace	*mnt_userns,
+	struct inode		*dir,
+	struct dentry		*dentry,
+	const char		*symname)
 {
 	struct inode	*inode;
 	struct xfs_inode *cip = NULL;
@@ -403,11 +407,12 @@ xfs_vn_symlink(
 
 STATIC int
 xfs_vn_rename(
-	struct inode	*odir,
-	struct dentry	*odentry,
-	struct inode	*ndir,
-	struct dentry	*ndentry,
-	unsigned int	flags)
+	struct user_namespace	*mnt_userns,
+	struct inode		*odir,
+	struct dentry		*odentry,
+	struct inode		*ndir,
+	struct dentry		*ndentry,
+	unsigned int		flags)
 {
 	struct inode	*new_inode = d_inode(ndentry);
 	int		omode = 0;
@@ -529,6 +534,7 @@ xfs_stat_blksize(
 
 STATIC int
 xfs_vn_getattr(
+	struct user_namespace	*mnt_userns,
 	const struct path	*path,
 	struct kstat		*stat,
 	u32			request_mask,
@@ -1047,6 +1053,7 @@ xfs_vn_setattr_size(
 
 STATIC int
 xfs_vn_setattr(
+	struct user_namespace	*mnt_userns,
 	struct dentry		*dentry,
 	struct iattr		*iattr)
 {
@@ -1144,9 +1151,10 @@ xfs_vn_fiemap(
 
 STATIC int
 xfs_vn_tmpfile(
-	struct inode	*dir,
-	struct dentry	*dentry,
-	umode_t		mode)
+	struct user_namespace	*mnt_userns,
+	struct inode		*dir,
+	struct dentry		*dentry,
+	umode_t			mode)
 {
 	return xfs_generic_create(dir, dentry, mode, 0, true);
 }