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/9p/acl.c b/fs/9p/acl.c
index 9a1d42630751..15b679166201 100644
--- a/fs/9p/acl.c
+++ b/fs/9p/acl.c
@@ -37,7 +37,7 @@ static struct posix_acl *__v9fs_get_acl(struct p9_fid *fid, char *name)
                         return ERR_PTR(-ENOMEM);
                 size = v9fs_fid_xattr_get(fid, name, value, size);
                 if (size > 0) {
-                        acl = posix_acl_from_xattr(value, size);
+                        acl = posix_acl_from_xattr(&init_user_ns, value, size);
                         if (IS_ERR(acl))
                                 goto err_out;
                 }
@@ -131,7 +131,7 @@ static int v9fs_set_acl(struct dentry *dentry, int type, struct posix_acl *acl)
         buffer = kmalloc(size, GFP_KERNEL);
         if (!buffer)
                 return -ENOMEM;
-        retval = posix_acl_to_xattr(acl, buffer, size);
+        retval = posix_acl_to_xattr(&init_user_ns, acl, buffer, size);
         if (retval < 0)
                 goto err_free_out;
         switch (type) {
@@ -251,7 +251,7 @@ static int v9fs_xattr_get_acl(struct dentry *dentry, const char *name,
                 return PTR_ERR(acl);
         if (acl == NULL)
                 return -ENODATA;
-        error = posix_acl_to_xattr(acl, buffer, size);
+        error = posix_acl_to_xattr(&init_user_ns, acl, buffer, size);
         posix_acl_release(acl);
 
         return error;
@@ -304,7 +304,7 @@ static int v9fs_xattr_set_acl(struct dentry *dentry, const char *name,
                 return -EPERM;
         if (value) {
                 /* update the cached acl 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);
                 else if (acl) {