[PATCH] knfsd: nfsd4: fix acl xattr length return

[PATCH] knfsd: nfsd4: fix acl xattr length return

We should be using the length from the second vfs_getxattr, in case it
changed.  (Note: there's still a small race here; we could end up returning
-ENOMEM if the length increased between the first and second call.  I don't
know whether it's worth spending a lot of effort to fix that.)

This makes XFS ACLs usable on NFS exports, which they currently aren't, since
XFS appears to be returning a too-large value for vfs_getxattr() when it's
passed a NULL buffer.  So there's probably an XFS bug here too, though since
getxattr with a NULL buffer is usually used to decide how much memory to
allocate, it may be a fairly harmless bug in most cases.

Signed-off-by: J. Bruce Fields <[email protected]>
Signed-off-by: Neil Brown <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>