From b4e39f3eccd6734f1ed13c700c136e3aef1777f8 Mon Sep 17 00:00:00 2001
From: "Frank S. Filz" <ffilzlnx@mindspring.com>
Date: Wed, 11 May 2022 14:35:53 -0700
Subject: [PATCH] libcephfs: Add nonblocking readv/writev I/O interface

Signed-off-by: Frank S. Filz <ffilzlnx@mindspring.com>
---
 src/include/cephfs/libcephfs.h | 13 +++++++++++++
 src/libcephfs.cc               | 27 +++++++++++++++++++++++++++
 2 files changed, 40 insertions(+)

diff --git a/src/include/cephfs/libcephfs.h b/src/include/cephfs/libcephfs.h
index dc62698fa48..703dd900b5d 100644
--- a/src/include/cephfs/libcephfs.h
+++ b/src/include/cephfs/libcephfs.h
@@ -118,6 +118,17 @@ struct ceph_snapdiff_entry_t {
   uint64_t snapid; //should be snapid_t but prefer not to exposure it
 };
 
+struct ceph_ll_io_info {
+  void (*callback) (struct ceph_ll_io_info *cb_info);
+  void *priv; // private for caller
+  struct Fh *fh;
+  const struct iovec *iov;
+  int iovcnt;
+  int64_t off;
+  int64_t result;
+  bool write;
+};
+
 /* setattr mask bits (up to an int in size) */
 #ifndef CEPH_SETATTR_MODE
 #define CEPH_SETATTR_MODE		(1 << 0)
@@ -1934,6 +1945,8 @@ int64_t ceph_ll_readv(struct ceph_mount_info *cmount, struct Fh *fh,
 		      const struct iovec *iov, int iovcnt, int64_t off);
 int64_t ceph_ll_writev(struct ceph_mount_info *cmount, struct Fh *fh,
 		       const struct iovec *iov, int iovcnt, int64_t off);
+int64_t ceph_ll_nonblocking_readv_writev(struct ceph_mount_info *cmount,
+					 struct ceph_ll_io_info *io_info);
 int ceph_ll_close(struct ceph_mount_info *cmount, struct Fh* filehandle);
 int ceph_ll_iclose(struct ceph_mount_info *cmount, struct Inode *in, int mode);
 /**
diff --git a/src/libcephfs.cc b/src/libcephfs.cc
index 51e73efdb65..a9387c32502 100644
--- a/src/libcephfs.cc
+++ b/src/libcephfs.cc
@@ -17,6 +17,7 @@
 #include <string.h>
 #include <string>
 
+#include "include/Context.h"
 #include "auth/Crypto.h"
 #include "client/Client.h"
 #include "client/Inode.h"
@@ -2018,6 +2019,32 @@ extern "C" int64_t ceph_ll_writev(class ceph_mount_info *cmount,
   return (cmount->get_client()->ll_writev(fh, iov, iovcnt, off));
 }
 
+class LL_Onfinish : public Context {
+public:
+  LL_Onfinish(struct ceph_ll_io_info *io_info)
+    : io_info(io_info) {}
+  bufferlist bl;
+private:
+  struct ceph_ll_io_info *io_info;
+  void finish(int r) override {
+    if (!io_info->write && r > 0) {
+      copy_bufferlist_to_iovec(io_info->iov, io_info->iovcnt, &bl, r);
+    }
+    io_info->result = r;
+    io_info->callback(io_info);
+  }
+};
+
+extern "C" int64_t ceph_ll_nonblocking_readv_writev(class ceph_mount_info *cmount,
+						    struct ceph_ll_io_info *io_info)
+{
+  LL_Onfinish *onfinish = new LL_Onfinish(io_info);
+
+  return (cmount->get_client()->ll_preadv_pwritev(
+			io_info->fh, io_info->iov, io_info->iovcnt,
+			io_info->off, io_info->write, onfinish, &onfinish->bl));
+}
+
 extern "C" int ceph_ll_close(class ceph_mount_info *cmount, Fh* fh)
 {
   return (cmount->get_client()->ll_release(fh));
-- 
2.39.5