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, 23 insertions, 16 deletions

diff --git a/fs/btrfs/acl.c b/fs/btrfs/acl.c
index d12a5a8730a8..d95eb5c8cb37 100644
--- a/fs/btrfs/acl.c
+++ b/fs/btrfs/acl.c
@@ -107,7 +107,8 @@ out:
 	return ret;
 }
 
-int btrfs_set_acl(struct inode *inode, struct posix_acl *acl, int type)
+int btrfs_set_acl(struct user_namespace *mnt_userns, struct inode *inode,
+		  struct posix_acl *acl, int type)
 {
 	int ret;
 	umode_t old_mode = inode->i_mode;
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index e6e37591f1de..9c0b43853cd2 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -3625,7 +3625,8 @@ static inline int __btrfs_fs_compat_ro(struct btrfs_fs_info *fs_info, u64 flag)
 /* acl.c */
 #ifdef CONFIG_BTRFS_FS_POSIX_ACL
 struct posix_acl *btrfs_get_acl(struct inode *inode, int type);
-int btrfs_set_acl(struct inode *inode, struct posix_acl *acl, int type);
+int btrfs_set_acl(struct user_namespace *mnt_userns, struct inode *inode,
+		  struct posix_acl *acl, int type);
 int btrfs_init_acl(struct btrfs_trans_handle *trans,
 		   struct inode *inode, struct inode *dir);
 #else
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index a63faed171de..c0b11db98e5e 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -5045,7 +5045,8 @@ static int btrfs_setsize(struct inode *inode, struct iattr *attr)
 	return ret;
 }
 
-static int btrfs_setattr(struct dentry *dentry, struct iattr *attr)
+static int btrfs_setattr(struct user_namespace *mnt_userns, struct dentry *dentry,
+			 struct iattr *attr)
 {
 	struct inode *inode = d_inode(dentry);
 	struct btrfs_root *root = BTRFS_I(inode)->root;
@@ -6352,8 +6353,8 @@ static int btrfs_add_nondir(struct btrfs_trans_handle *trans,
 	return err;
 }
 
-static int btrfs_mknod(struct inode *dir, struct dentry *dentry,
-			umode_t mode, dev_t rdev)
+static int btrfs_mknod(struct user_namespace *mnt_userns, struct inode *dir,
+		       struct dentry *dentry, umode_t mode, dev_t rdev)
 {
 	struct btrfs_fs_info *fs_info = btrfs_sb(dir->i_sb);
 	struct btrfs_trans_handle *trans;
@@ -6416,8 +6417,8 @@ out_unlock:
 	return err;
 }
 
-static int btrfs_create(struct inode *dir, struct dentry *dentry,
-			umode_t mode, bool excl)
+static int btrfs_create(struct user_namespace *mnt_userns, struct inode *dir,
+			struct dentry *dentry, umode_t mode, bool excl)
 {
 	struct btrfs_fs_info *fs_info = btrfs_sb(dir->i_sb);
 	struct btrfs_trans_handle *trans;
@@ -6561,7 +6562,8 @@ fail:
 	return err;
 }
 
-static int btrfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
+static int btrfs_mkdir(struct user_namespace *mnt_userns, struct inode *dir,
+		       struct dentry *dentry, umode_t mode)
 {
 	struct btrfs_fs_info *fs_info = btrfs_sb(dir->i_sb);
 	struct inode *inode = NULL;
@@ -8816,7 +8818,8 @@ fail:
 	return -ENOMEM;
 }
 
-static int btrfs_getattr(const struct path *path, struct kstat *stat,
+static int btrfs_getattr(struct user_namespace *mnt_userns,
+			 const struct path *path, struct kstat *stat,
 			 u32 request_mask, unsigned int flags)
 {
 	u64 delalloc_bytes;
@@ -9333,9 +9336,9 @@ out_notrans:
 	return ret;
 }
 
-static int btrfs_rename2(struct inode *old_dir, struct dentry *old_dentry,
-			 struct inode *new_dir, struct dentry *new_dentry,
-			 unsigned int flags)
+static int btrfs_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)
 {
 	if (flags & ~(RENAME_NOREPLACE | RENAME_EXCHANGE | RENAME_WHITEOUT))
 		return -EINVAL;
@@ -9543,8 +9546,8 @@ out:
 	return ret;
 }
 
-static int btrfs_symlink(struct inode *dir, struct dentry *dentry,
-			 const char *symname)
+static int btrfs_symlink(struct user_namespace *mnt_userns, struct inode *dir,
+			 struct dentry *dentry, const char *symname)
 {
 	struct btrfs_fs_info *fs_info = btrfs_sb(dir->i_sb);
 	struct btrfs_trans_handle *trans;
@@ -9878,7 +9881,8 @@ static int btrfs_set_page_dirty(struct page *page)
 	return __set_page_dirty_nobuffers(page);
 }
 
-static int btrfs_permission(struct inode *inode, int mask)
+static int btrfs_permission(struct user_namespace *mnt_userns,
+			    struct inode *inode, int mask)
 {
 	struct btrfs_root *root = BTRFS_I(inode)->root;
 	umode_t mode = inode->i_mode;
@@ -9893,7 +9897,8 @@ static int btrfs_permission(struct inode *inode, int mask)
 	return generic_permission(&init_user_ns, inode, mask);
 }
 
-static int btrfs_tmpfile(struct inode *dir, struct dentry *dentry, umode_t mode)
+static int btrfs_tmpfile(struct user_namespace *mnt_userns, struct inode *dir,
+			 struct dentry *dentry, umode_t mode)
 {
 	struct btrfs_fs_info *fs_info = btrfs_sb(dir->i_sb);
 	struct btrfs_trans_handle *trans;