extended attributes limitation of xattr_size_max

[Olga Kornievskaia <aglo@umich.edu>]

Hi Andreas and Bruce,

I thought of you folks as somebody who might have a strong opinion on
the topic. Right now an NFS client is limited to setting and getting
ACLs that can't be larger than 64K (XATTR_SIZE_MAX) (where some NFS
server don't have such limit on the ACL size). There are limits in
fs/xattr.c during getting and setting xattrs. I believe that's because
linux local xattr system is limited to that particular constraint.
However, an NFS acl that uses the xattr interface can be larger than
that. Is it at all possible to suggest to the larger FS community to
remove those limits or would that be a non-starter?

diff --git a/fs/xattr.c b/fs/xattr.c
index 90dd78f..52a3f91 100644
--- a/fs/xattr.c
+++ b/fs/xattr.c
@@ -428,8 +428,6 @@ int __vfs_setxattr_noperm(struct dentry *dentry,
const char *name,
  return error;

  if (size) {
- if (size > XATTR_SIZE_MAX)
- return -E2BIG;
  kvalue = kvmalloc(size, GFP_KERNEL);
  if (!kvalue)
  return -ENOMEM;
@@ -528,8 +526,6 @@ static int path_setxattr(const char __user *pathname,
  return error;

  if (size) {
- if (size > XATTR_SIZE_MAX)
- size = XATTR_SIZE_MAX;
  kvalue = kvzalloc(size, GFP_KERNEL);
  if (!kvalue)
  return -ENOMEM;
--