From: Frank van der Linden <fllinden@amazon.com>
Date: Tue, 23 Jun 2020 22:39:27 +0000 (+0000)
Subject: nfsd: add fattr support for user extended attributes
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=0e885e846d96df0c8a4a829b1ad355a82ccda656;p=linux.git

nfsd: add fattr support for user extended attributes

Check if user extended attributes are supported for an inode,
and return the answer when being queried for file attributes.

An exported filesystem can now signal its RFC8276 user extended
attributes capability.

Signed-off-by: Frank van der Linden <fllinden@amazon.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
---

diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
index 8bacc0ceae19a..259d5ad0e3f47 100644
--- a/fs/nfsd/nfs4xdr.c
+++ b/fs/nfsd/nfs4xdr.c
@@ -3213,6 +3213,15 @@ out_acl:
 	}
 #endif
 
+	if (bmval2 & FATTR4_WORD2_XATTR_SUPPORT) {
+		p = xdr_reserve_space(xdr, 4);
+		if (!p)
+			goto out_resource;
+		err = xattr_supported_namespace(d_inode(dentry),
+						XATTR_USER_PREFIX);
+		*p++ = cpu_to_be32(err == 0);
+	}
+
 	attrlen = htonl(xdr->buf->len - attrlen_offset - 4);
 	write_bytes_to_xdr_buf(xdr->buf, attrlen_offset, &attrlen, 4);
 	status = nfs_ok;