userns: Pass a userns parameter into posix_acl_to_xattr and posix_acl_from_xattr

 - Pass the user namespace the uid and gid values in the xattr are stored
   in into posix_acl_from_xattr.

 - Pass the user namespace kuid and kgid values should be converted into
   when storing uid and gid values in an xattr in posix_acl_to_xattr.

- Modify all callers of posix_acl_from_xattr and posix_acl_to_xattr to
  pass in &init_user_ns.

In the short term this change is not strictly needed but it makes the
code clearer.  In the longer term this change is necessary to be able to
mount filesystems outside of the initial user namespace that natively
store posix acls in the linux xattr format.

Cc: Theodore Tso <tytso@mit.edu>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andreas Dilger <adilger.kernel@dilger.ca>
Cc: Jan Kara <jack@suse.cz>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>

1 files changed, 4 insertions, 4 deletions

diff --git a/fs/btrfs/acl.c b/fs/btrfs/acl.c
index 761e2cd..0c16e3d 100644
--- a/fs/btrfs/acl.c
+++ b/fs/btrfs/acl.c
@@ -61,7 +61,7 @@ struct posix_acl *btrfs_get_acl(struct inode *inode, int type)
 		size = __btrfs_getxattr(inode, name, value, size);
 	}
 	if (size > 0) {
-		acl = posix_acl_from_xattr(value, size);
+		acl = posix_acl_from_xattr(&init_user_ns, value, size);
 	} else if (size == -ENOENT || size == -ENODATA || size == 0) {
 		/* FIXME, who returns -ENOENT?  I think nobody */
 		acl = NULL;
@@ -91,7 +91,7 @@ static int btrfs_xattr_acl_get(struct dentry *dentry, const char *name,
 		return PTR_ERR(acl);
 	if (acl == NULL)
 		return -ENODATA;
-	ret = posix_acl_to_xattr(acl, value, size);
+	ret = posix_acl_to_xattr(&init_user_ns, acl, value, size);
 	posix_acl_release(acl);
 
 	return ret;
@@ -141,7 +141,7 @@ static int btrfs_set_acl(struct btrfs_trans_handle *trans,
 			goto out;
 		}
 
-		ret = posix_acl_to_xattr(acl, value, size);
+		ret = posix_acl_to_xattr(&init_user_ns, acl, value, size);
 		if (ret < 0)
 			goto out;
 	}
@@ -169,7 +169,7 @@ static int btrfs_xattr_acl_set(struct dentry *dentry, const char *name,
 		return -EOPNOTSUPP;
 
 	if (value) {
-		acl = posix_acl_from_xattr(value, size);
+		acl = posix_acl_from_xattr(&init_user_ns, value, size);
 		if (IS_ERR(acl))
 			return PTR_ERR(acl);