On Tue, May 14, 2013 at 02:15:26PM -0700, Zach Brown wrote:
> This crude patch illustrates the simplest plumbing involved in
> supporting sys_call_range with the NFS COPY operation that's pending in
> the 4.2 draft spec.
>
> The patch is based on a previous prototype that used the COPY op to
> implement sys_copyfileat which created a new file (based on the ocfs2
> reflink ioctl). By contrast, this copies file contents between existing
> files.
>
> There's still a lot of implementation and testing to do, but this can
> get discussion going.
I'm using:
git://github.com/loghyr/NFSv4.2
as my reference for the draft protocol.
On a quick skim, one thing this is missing before it complies is a
client implementation of CB_OFFLOAD: "If a client desires an
intra-server file copy, then it MUST support the COPY and CB_OFFLOAD
operations."
The server doesn't have to implement CB_OFFLOAD, though, so we should
ditch these todo's:
> +/*
> + * XXX:
> + * - do something with stateids :)
> + * - implement callback results and OFFLOAD_ABORT
> + * - inter-server copies?
> + */
...
> + /* don't support async callbacks yet */
...
lest someone go try to implement them for no reason. (Stranger things
have happened.)
Nits, possibly to ignore for now:
> + copy->u.ok.cr_callback_id_length = 0;
> +
> + return status;
> +}
> +
> /* This routine never returns NFS_OK! If there are no other errors, it
> * will return NFSERR_SAME or NFSERR_NOT_SAME depending on whether the
> * attributes matched. VERIFY is implemented by mapping NFSERR_SAME
> @@ -1798,6 +1829,10 @@ static struct nfsd4_operation nfsd4_ops[] = {
> .op_get_currentstateid = (stateid_getter)nfsd4_get_freestateid,
> .op_rsize_bop = (nfsd4op_rsize)nfsd4_only_status_rsize,
> },
> + [OP_COPY] = {
> + .op_func = (nfsd4op_func)nfsd4_copy,
> + .op_name = "OP_COPY",
> + },
There's some more boilerplate to fill in (see other ops).
> +static __be32
> nfsd4_decode_noop(struct nfsd4_compoundargs *argp, void *p)
> {
> return nfs_ok;
> @@ -1557,6 +1577,7 @@ static nfsd4_dec nfsd41_dec_ops[] = {
> [OP_WANT_DELEGATION] = (nfsd4_dec)nfsd4_decode_notsupp,
> [OP_DESTROY_CLIENTID] = (nfsd4_dec)nfsd4_decode_destroy_clientid,
> [OP_RECLAIM_COMPLETE] = (nfsd4_dec)nfsd4_decode_reclaim_complete,
> + [OP_COPY] = (nfsd4_dec)nfsd4_decode_copy,
And this should be made 4.2-specific.
> };
>
> struct nfsd4_minorversion_ops {
> @@ -3394,6 +3415,27 @@ nfsd4_encode_test_stateid(struct nfsd4_compoundres
> *resp, __be32 nfserr,
> }
>
> static __be32
> +nfsd4_encode_copy(struct nfsd4_compoundres *resp, __be32 nfserr,
> + struct nfsd4_copy *copy)
> +{
> + __be32 *p;
> +
> + if (!nfserr) {
> + RESERVE_SPACE(4);
> + WRITE32(copy->u.ok.cr_callback_id_length);
> + ADJUST_ARGS();
> + if (copy->u.ok.cr_callback_id_length == 1)
> + nfsd4_encode_stateid(resp, copy->u.ok.cr_callback_id);
> + } else {
> + RESERVE_SPACE(8);
> + WRITE64(copy->u.cr_bytes_copied);
> + ADJUST_ARGS();
> + }
> +
> + return nfserr;
> +}
> +
> +static __be32
> nfsd4_encode_noop(struct nfsd4_compoundres *resp, __be32 nfserr, void *p)
> {
> return nfserr;
> @@ -3465,6 +3507,7 @@ static nfsd4_enc nfsd4_enc_ops[] = {
> [OP_WANT_DELEGATION] = (nfsd4_enc)nfsd4_encode_noop,
> [OP_DESTROY_CLIENTID] = (nfsd4_enc)nfsd4_encode_noop,
> [OP_RECLAIM_COMPLETE] = (nfsd4_enc)nfsd4_encode_noop,
> + [OP_COPY] = (nfsd4_enc)nfsd4_encode_copy,
> };
>
> /*
> diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c
> index 84ce601..0c1b427 100644
> --- a/fs/nfsd/vfs.c
> +++ b/fs/nfsd/vfs.c
> @@ -28,6 +28,8 @@
> #include <asm/uaccess.h>
> #include <linux/exportfs.h>
> #include <linux/writeback.h>
> +#include <linux/fs_struct.h>
> +#include <linux/kmod.h>
>
> #ifdef CONFIG_NFSD_V3
> #include "xdr3.h"
> @@ -621,6 +623,45 @@ int nfsd4_is_junction(struct dentry *dentry)
> return 0;
> return 1;
> }
> +
> +__be32
> +nfsd_copy_range(struct svc_rqst *rqstp, struct svc_fh *fhp_in, u64 pos_in,
> + struct svc_fh *fhp_out, u64 pos_out, u64 count)
> +{
> + struct file *filp_in = NULL;
> + struct file *filp_out = NULL;
> + int err;
> +
> + /* XXX verify pos and count within sane limits? */
> +
> + err = nfsd_open(rqstp, fhp_in, S_IFREG, NFSD_MAY_READ, &filp_in);
> + if (err)
> + goto out;
> +
> + err = nfsd_open(rqstp, fhp_out, S_IFREG, NFSD_MAY_WRITE, &filp_out);
> + if (err)
> + goto out;
Looking at the xdr... the COPY operation takes stateid's, which nfsd can
use to look up files, so the opens shouldn't be required.
--b.
> +
> + err = vfs_copy_range(filp_in, pos_in, filp_out, pos_out, count);
> + /* fall back if .copy_range isn't supported */
> +
> + if (!err && EX_ISSYNC(fhp_out->fh_export))
> + err = vfs_fsync_range(filp_out, pos_out, pos_out + count-1, 0);
> +
> +out:
> + if (filp_in)
> + nfsd_close(filp_in);
> + if (filp_out)
> + nfsd_close(filp_out);
> +
> + if (err < 0)
> + err = nfserrno(err);
> + else
> + err = 0;
> +
> + return err;
> +}
> +
> #endif /* defined(CONFIG_NFSD_V4) */
>
> #ifdef CONFIG_NFSD_V3
> diff --git a/fs/nfsd/vfs.h b/fs/nfsd/vfs.h
> index 5b58941..bbc9483 100644
> --- a/fs/nfsd/vfs.h
> +++ b/fs/nfsd/vfs.h
> @@ -85,6 +85,9 @@ __be32 nfsd_symlink(struct svc_rqst *, struct
> svc_fh *,
> struct svc_fh *res, struct iattr *);
> __be32 nfsd_link(struct svc_rqst *, struct svc_fh *,
> char *, int, struct svc_fh *);
> +__be32 nfsd_copy_range(struct svc_rqst *,
> + struct svc_fh *, u64,
> + struct svc_fh *, u64, u64);
> __be32 nfsd_rename(struct svc_rqst *,
> struct svc_fh *, char *, int,
> struct svc_fh *, char *, int);
> diff --git a/fs/nfsd/xdr4.h b/fs/nfsd/xdr4.h
> index 3b271d2..95fd1c3 100644
> --- a/fs/nfsd/xdr4.h
> +++ b/fs/nfsd/xdr4.h
> @@ -426,6 +426,26 @@ struct nfsd4_reclaim_complete {
> u32 rca_one_fs;
> };
>
> +struct nfsd4_copy {
> + /* request */
> + u64 ca_src_offset;
> + u64 ca_dst_offset;
> + u64 ca_count;
> + u32 ca_flags;
> + u32 ca_destinationlen;
> + char * ca_destination;
> +
> + /* response */
> + union {
> + struct {
> + u32 cr_callback_id_length;
> + stateid_t * cr_callback_id;
> + } ok;
> + u64 cr_bytes_copied;
> + } u;
> +
> +};
> +
> struct nfsd4_op {
> int opnum;
> __be32 status;
> @@ -471,6 +491,7 @@ struct nfsd4_op {
> struct nfsd4_reclaim_complete reclaim_complete;
> struct nfsd4_test_stateid test_stateid;
> struct nfsd4_free_stateid free_stateid;
> + struct nfsd4_copy copy;
> } u;
> struct nfs4_replay * replay;
> };
> diff --git a/include/linux/nfs4.h b/include/linux/nfs4.h
> index 7b8fc73..6be484e 100644
> --- a/include/linux/nfs4.h
> +++ b/include/linux/nfs4.h
> @@ -100,6 +100,7 @@ enum nfs_opnum4 {
> OP_WANT_DELEGATION = 56,
> OP_DESTROY_CLIENTID = 57,
> OP_RECLAIM_COMPLETE = 58,
> + OP_COPY = 59,
>
> OP_ILLEGAL = 10044,
> };
> @@ -108,7 +109,7 @@ enum nfs_opnum4 {
> Needs to be updated if more operations are defined in future.*/
>
> #define FIRST_NFS4_OP OP_ACCESS
> -#define LAST_NFS4_OP OP_RECLAIM_COMPLETE
> +#define LAST_NFS4_OP OP_COPY
>
> enum nfsstat4 {
> NFS4_OK = 0,
> @@ -456,6 +457,9 @@ enum {
> NFSPROC4_CLNT_GETDEVICELIST,
> NFSPROC4_CLNT_BIND_CONN_TO_SESSION,
> NFSPROC4_CLNT_DESTROY_CLIENTID,
> +
> + /* nfs42 */
> + NFSPROC4_CLNT_COPY,
> };
>
> /* nfs41 types */
> diff --git a/include/linux/nfs_xdr.h b/include/linux/nfs_xdr.h
> index 104b62f..2256e31 100644
> --- a/include/linux/nfs_xdr.h
> +++ b/include/linux/nfs_xdr.h
> @@ -1184,6 +1184,28 @@ struct nfs41_free_stateid_res {
> unsigned int status;
> };
>
> +struct nfs_copy_args {
> + struct nfs_fh *fh;
> + struct nfs_fh *dir_fh;
> + u32 *bitmask;
> + __u64 src_offset;
> + __u64 dst_offset;
> + __u64 count;
> + __u32 flags;
> + const struct qstr *destination;
> + struct nfs4_sequence_args seq_args;
> +};
> +
> +struct nfs_copy_res {
> + struct nfs_fh *fh;
> + struct nfs_fattr *fattr;
> + __u32 callback_id_length;
> + nfs4_stateid *callback_id;
> + __u64 bytes_copied;
> + const struct nfs_server *server;
> + struct nfs4_sequence_res seq_res;
> +};
> +
> #else
>
> struct pnfs_ds_commit_info {
> @@ -1433,6 +1455,8 @@ struct nfs_rpc_ops {
> struct nfs_server *(*create_server)(struct nfs_mount_info *, struct
> nfs_subversion *);
> struct nfs_server *(*clone_server)(struct nfs_server *, struct nfs_fh *,
> struct nfs_fattr *,
> rpc_authflavor_t);
> + loff_t (*copy) (struct inode *, struct inode *, struct qstr *,
> + int, loff_t, loff_t, loff_t);
> };
>
> /*
> --
> 1.7.11.7
>
> --
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