nfsd: implement the NFSv4.2 CLONE operation

This is basically a remote version of the btrfs CLONE operation,
so the implementation is fairly trivial.  Made even more trivial
by stealing the XDR code and general framework Anna Schumaker's
COPY prototype.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: J. Bruce Fields <bfields@fieldses.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

5 files changed, 88 insertions, 0 deletions

diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c
index 3ba10a3534f1..819ad812c71b 100644
--- a/fs/nfsd/nfs4proc.c
+++ b/fs/nfsd/nfs4proc.c
@@ -1012,6 +1012,47 @@ nfsd4_write(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
 }
 
 static __be32
+nfsd4_clone(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
+                struct nfsd4_clone *clone)
+{
+        struct file *src, *dst;
+        __be32 status;
+
+        status = nfs4_preprocess_stateid_op(rqstp, cstate, &cstate->save_fh,
+                                            &clone->cl_src_stateid, RD_STATE,
+                                            &src, NULL);
+        if (status) {
+                dprintk("NFSD: %s: couldn't process src stateid!\n", __func__);
+                goto out;
+        }
+
+        status = nfs4_preprocess_stateid_op(rqstp, cstate, &cstate->current_fh,
+                                            &clone->cl_dst_stateid, WR_STATE,
+                                            &dst, NULL);
+        if (status) {
+                dprintk("NFSD: %s: couldn't process dst stateid!\n", __func__);
+                goto out_put_src;
+        }
+
+        /* fix up for NFS-specific error code */
+        if (!S_ISREG(file_inode(src)->i_mode) ||
+            !S_ISREG(file_inode(dst)->i_mode)) {
+                status = nfserr_wrong_type;
+                goto out_put_dst;
+        }
+
+        status = nfsd4_clone_file_range(src, clone->cl_src_pos,
+                        dst, clone->cl_dst_pos, clone->cl_count);
+
+out_put_dst:
+        fput(dst);
+out_put_src:
+        fput(src);
+out:
+        return status;
+}
+
+static __be32
 nfsd4_fallocate(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
                 struct nfsd4_fallocate *fallocate, int flags)
 {
@@ -2281,6 +2322,12 @@ static struct nfsd4_operation nfsd4_ops[] = {
                 .op_name = "OP_DEALLOCATE",
                 .op_rsize_bop = (nfsd4op_rsize)nfsd4_only_status_rsize,
         },
+        [OP_CLONE] = {
+                .op_func = (nfsd4op_func)nfsd4_clone,
+                .op_flags = OP_MODIFIES_SOMETHING | OP_CACHEME,
+                .op_name = "OP_CLONE",
+                .op_rsize_bop = (nfsd4op_rsize)nfsd4_only_status_rsize,
+        },
         [OP_SEEK] = {
                 .op_func = (nfsd4op_func)nfsd4_seek,
                 .op_name = "OP_SEEK",
diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
index 51c9e9ca39a4..924416f91fdd 100644
--- a/fs/nfsd/nfs4xdr.c
+++ b/fs/nfsd/nfs4xdr.c
@@ -1675,6 +1675,25 @@ nfsd4_decode_fallocate(struct nfsd4_compoundargs *argp,
 }
 
 static __be32
+nfsd4_decode_clone(struct nfsd4_compoundargs *argp, struct nfsd4_clone *clone)
+{
+        DECODE_HEAD;
+
+        status = nfsd4_decode_stateid(argp, &clone->cl_src_stateid);
+        if (status)
+                return status;
+        status = nfsd4_decode_stateid(argp, &clone->cl_dst_stateid);
+        if (status)
+                return status;
+
+        READ_BUF(8 + 8 + 8);
+        p = xdr_decode_hyper(p, &clone->cl_src_pos);
+        p = xdr_decode_hyper(p, &clone->cl_dst_pos);
+        p = xdr_decode_hyper(p, &clone->cl_count);
+        DECODE_TAIL;
+}
+
+static __be32
 nfsd4_decode_seek(struct nfsd4_compoundargs *argp, struct nfsd4_seek *seek)
 {
         DECODE_HEAD;
@@ -1785,6 +1804,7 @@ static nfsd4_dec nfsd4_dec_ops[] = {
         [OP_READ_PLUS]          = (nfsd4_dec)nfsd4_decode_notsupp,
         [OP_SEEK]               = (nfsd4_dec)nfsd4_decode_seek,
         [OP_WRITE_SAME]         = (nfsd4_dec)nfsd4_decode_notsupp,
+        [OP_CLONE]              = (nfsd4_dec)nfsd4_decode_clone,
 };
 
 static inline bool
@@ -4292,6 +4312,7 @@ static nfsd4_enc nfsd4_enc_ops[] = {
         [OP_READ_PLUS]          = (nfsd4_enc)nfsd4_encode_noop,
         [OP_SEEK]               = (nfsd4_enc)nfsd4_encode_seek,
         [OP_WRITE_SAME]         = (nfsd4_enc)nfsd4_encode_noop,
+        [OP_CLONE]              = (nfsd4_enc)nfsd4_encode_noop,
 };
 
 /*
diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c
index 994d66fbb446..5411bf09b810 100644
--- a/fs/nfsd/vfs.c
+++ b/fs/nfsd/vfs.c
@@ -36,6 +36,7 @@
 #endif /* CONFIG_NFSD_V3 */
 
 #ifdef CONFIG_NFSD_V4
+#include "../internal.h"
 #include "acl.h"
 #include "idmap.h"
 #endif /* CONFIG_NFSD_V4 */
@@ -498,6 +499,13 @@ __be32 nfsd4_set_nfs4_label(struct svc_rqst *rqstp, struct svc_fh *fhp,
 }
 #endif
 
+__be32 nfsd4_clone_file_range(struct file *src, u64 src_pos, struct file *dst,
+                u64 dst_pos, u64 count)
+{
+        return nfserrno(vfs_clone_file_range(src, src_pos, dst, dst_pos,
+                        count));
+}
+
 __be32 nfsd4_vfs_fallocate(struct svc_rqst *rqstp, struct svc_fh *fhp,
                            struct file *file, loff_t offset, loff_t len,
                            int flags)
diff --git a/fs/nfsd/vfs.h b/fs/nfsd/vfs.h
index fcfc48cbe136..c11ba316f23f 100644
--- a/fs/nfsd/vfs.h
+++ b/fs/nfsd/vfs.h
@@ -56,6 +56,8 @@ __be32          nfsd4_set_nfs4_label(struct svc_rqst *, struct svc_fh *,
                     struct xdr_netobj *);
 __be32          nfsd4_vfs_fallocate(struct svc_rqst *, struct svc_fh *,
                                     struct file *, loff_t, loff_t, int);
+__be32          nfsd4_clone_file_range(struct file *, u64, struct file *,
+                        u64, u64);
 #endif /* CONFIG_NFSD_V4 */
 __be32          nfsd_create(struct svc_rqst *, struct svc_fh *,
                                 char *name, int len, struct iattr *attrs,
diff --git a/fs/nfsd/xdr4.h b/fs/nfsd/xdr4.h
index ce7362c88b48..d9554813e58a 100644
--- a/fs/nfsd/xdr4.h
+++ b/fs/nfsd/xdr4.h
@@ -491,6 +491,15 @@ struct nfsd4_fallocate {
         u64             falloc_length;
 };
 
+struct nfsd4_clone {
+        /* request */
+        stateid_t       cl_src_stateid;
+        stateid_t       cl_dst_stateid;
+        u64             cl_src_pos;
+        u64             cl_dst_pos;
+        u64             cl_count;
+};
+
 struct nfsd4_seek {
         /* request */
         stateid_t       seek_stateid;
@@ -555,6 +564,7 @@ struct nfsd4_op {
                 /* NFSv4.2 */
                 struct nfsd4_fallocate          allocate;
                 struct nfsd4_fallocate          deallocate;
+                struct nfsd4_clone              clone;
                 struct nfsd4_seek               seek;
         } u;
         struct nfs4_replay *                    replay;