Re: [PATCH 03/13] NFSv4.2: query the server for extended attribute support

Mkrtchyan, Tigran
2020-03-12T16:15:14Z

Hi Frank,

----- Original Message -----
> From: "Frank van der Linden" <fllinden@amazon.com>
> To: "Trond Myklebust" <trond.myklebust@hammerspace.com>, "Anna Schumaker" <anna.schumaker@netapp.com>, "linux-nfs"
> <linux-nfs@vger.kernel.org>
> Cc: "Frank van der Linden" <fllinden@amazon.com>
> Sent: Wednesday, March 11, 2020 8:56:03 PM
> Subject: [PATCH 03/13] NFSv4.2: query the server for extended attribute support

> Query the server for extended attribute support, and record it
> as the NFS_CAP_XATTR flag in the server capabilities.
>
> Signed-off-by: Frank van der Linden <fllinden@amazon.com>
> ---
> fs/nfs/nfs4proc.c | 14 ++++++++++++--
> fs/nfs/nfs4xdr.c | 23 +++++++++++++++++++++++
> include/linux/nfs_fs_sb.h | 1 +
> include/linux/nfs_xdr.h | 1 +
> 4 files changed, 37 insertions(+), 2 deletions(-)
>
> diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
> index 69b7ab7a5815..47bbd7db9d18 100644
> --- a/fs/nfs/nfs4proc.c
> +++ b/fs/nfs/nfs4proc.c
> @@ -3742,6 +3742,7 @@ static void nfs4_close_context(struct nfs_open_context
> *ctx, int is_sync)
> static int _nfs4_server_capabilities(struct nfs_server *server, struct nfs_fh
> *fhandle)
> {
> u32 bitmask[3] = {}, minorversion = server->nfs_client->cl_minorversion;
> + u32 fattr4_word2_nfs42_mask;
> struct nfs4_server_caps_arg args = {
> .fhandle = fhandle,
> .bitmask = bitmask,
> @@ -3763,6 +3764,13 @@ static int _nfs4_server_capabilities(struct nfs_server
> *server, struct nfs_fh *f
> if (minorversion)
> bitmask[2] = FATTR4_WORD2_SUPPATTR_EXCLCREAT;
>
> + fattr4_word2_nfs42_mask = FATTR4_WORD2_NFS42_MASK;
> +
> + if (minorversion >= 2) {

I am not sure you need this extra check as by querying for FATTR4_WORD0_SUPPORTED_ATTRS
server already will return FATTR4_WORD2_XATTR_SUPPORT if supported.

Tigran.

> + bitmask[2] |= FATTR4_WORD2_XATTR_SUPPORT;
> + fattr4_word2_nfs42_mask |= FATTR4_WORD2_XATTR_SUPPORT;
> + }
> +
> status = nfs4_call_sync(server->client, server, &msg, &args.seq_args,
> &res.seq_res, 0);
> if (status == 0) {
> /* Sanity check the server answers */
> @@ -3775,7 +3783,7 @@ static int _nfs4_server_capabilities(struct nfs_server
> *server, struct nfs_fh *f
> res.attr_bitmask[2] &= FATTR4_WORD2_NFS41_MASK;
> break;
> case 2:
> - res.attr_bitmask[2] &= FATTR4_WORD2_NFS42_MASK;
> + res.attr_bitmask[2] &= fattr4_word2_nfs42_mask;
> }
> memcpy(server->attr_bitmask, res.attr_bitmask, sizeof(server->attr_bitmask));
> server->caps &= ~(NFS_CAP_ACLS|NFS_CAP_HARDLINKS|
> @@ -3783,7 +3791,7 @@ static int _nfs4_server_capabilities(struct nfs_server
> *server, struct nfs_fh *f
> NFS_CAP_MODE|NFS_CAP_NLINK|NFS_CAP_OWNER|
> NFS_CAP_OWNER_GROUP|NFS_CAP_ATIME|
> NFS_CAP_CTIME|NFS_CAP_MTIME|
> - NFS_CAP_SECURITY_LABEL);
> + NFS_CAP_SECURITY_LABEL|NFS_CAP_XATTR);
> if (res.attr_bitmask[0] & FATTR4_WORD0_ACL &&
> res.acl_bitmask & ACL4_SUPPORT_ALLOW_ACL)
> server->caps |= NFS_CAP_ACLS;
> @@ -3811,6 +3819,8 @@ static int _nfs4_server_capabilities(struct nfs_server
> *server, struct nfs_fh *f
> if (res.attr_bitmask[2] & FATTR4_WORD2_SECURITY_LABEL)
> server->caps |= NFS_CAP_SECURITY_LABEL;
> #endif
> + if (res.has_xattr)
> + server->caps |= NFS_CAP_XATTR;
> memcpy(server->attr_bitmask_nl, res.attr_bitmask,
> sizeof(server->attr_bitmask));
> server->attr_bitmask_nl[2] &= ~FATTR4_WORD2_SECURITY_LABEL;
> diff --git a/fs/nfs/nfs4xdr.c b/fs/nfs/nfs4xdr.c
> index 47817ef0aadb..bebc087a1433 100644
> --- a/fs/nfs/nfs4xdr.c
> +++ b/fs/nfs/nfs4xdr.c
> @@ -4201,6 +4201,26 @@ static int decode_attr_time_modify(struct xdr_stream
> *xdr, uint32_t *bitmap, str
> return status;
> }
>
> +static int decode_attr_xattrsupport(struct xdr_stream *xdr, uint32_t *bitmap,
> + uint32_t *res)
> +{
> + __be32 *p;
> +
> + *res = 0;
> + if (unlikely(bitmap[2] & (FATTR4_WORD2_XATTR_SUPPORT - 1U)))
> + return -EIO;
> + if (likely(bitmap[2] & FATTR4_WORD2_XATTR_SUPPORT)) {
> + p = xdr_inline_decode(xdr, 4);
> + if (unlikely(!p))
> + return -EIO;
> + *res = be32_to_cpup(p);
> + bitmap[2] &= ~FATTR4_WORD2_XATTR_SUPPORT;
> + }
> + dprintk("%s: XATTR support=%s\n", __func__,
> + *res == 0 ? "false" : "true");
> + return 0;
> +}
> +
> static int verify_attr_len(struct xdr_stream *xdr, unsigned int savep, uint32_t
> attrlen)
> {
> unsigned int attrwords = XDR_QUADLEN(attrlen);
> @@ -4371,6 +4391,9 @@ static int decode_server_caps(struct xdr_stream *xdr,
> struct nfs4_server_caps_re
> if ((status = decode_attr_exclcreat_supported(xdr, bitmap,
> res->exclcreat_bitmask)) != 0)
> goto xdr_error;
> + status = decode_attr_xattrsupport(xdr, bitmap, &res->has_xattr);
> + if (status != 0)
> + goto xdr_error;
> status = verify_attr_len(xdr, savep, attrlen);
> xdr_error:
> dprintk("%s: xdr returned %d!\n", __func__, -status);
> diff --git a/include/linux/nfs_fs_sb.h b/include/linux/nfs_fs_sb.h
> index 465fa98258a3..d881f7a38bc9 100644
> --- a/include/linux/nfs_fs_sb.h
> +++ b/include/linux/nfs_fs_sb.h
> @@ -281,5 +281,6 @@ struct nfs_server {
> #define NFS_CAP_OFFLOAD_CANCEL (1U << 25)
> #define NFS_CAP_LAYOUTERROR (1U << 26)
> #define NFS_CAP_COPY_NOTIFY (1U << 27)
> +#define NFS_CAP_XATTR (1U << 28)
>
> #endif
> diff --git a/include/linux/nfs_xdr.h b/include/linux/nfs_xdr.h
> index 94c77ed55ce1..5076fe42c693 100644
> --- a/include/linux/nfs_xdr.h
> +++ b/include/linux/nfs_xdr.h
> @@ -1178,6 +1178,7 @@ struct nfs4_server_caps_res {
> u32 has_links;
> u32 has_symlinks;
> u32 fh_expire_type;
> + u32 has_xattr;
> };
>
> #define NFS4_PATHNAME_MAXCOMPONENTS 512
> --
> 2.16.6