[PATCH 14/14] nfsd: add fattr support for user extended attributes

Frank van der Linden
2020-03-11T20:00:02Z

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>
---
fs/nfsd/nfs4xdr.c | 9 +++++++++
1 file changed, 9 insertions(+)

diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
index 41c8b95ca1c5..d4a45cfefb86 100644
--- a/fs/nfsd/nfs4xdr.c
+++ b/fs/nfsd/nfs4xdr.c
@@ -3229,6 +3229,15 @@ nfsd4_encode_fattr(struct xdr_stream *xdr, struct svc_fh *fhp,
}
#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;
--
2.16.6