s3: Add vfs_aio_posix

Signed-off-by: Jeremy Allison <jra@samba.org>

1 files changed, 243 insertions, 0 deletions

diff --git a/source3/modules/vfs_aio_posix.c b/source3/modules/vfs_aio_posix.c
new file mode 100644
index 0000000000..97b102b5e4
--- /dev/null
+++ b/source3/modules/vfs_aio_posix.c
@@ -0,0 +1,243 @@
+/*
+ * Simulate pread_send/recv and pwrite_send/recv using posix aio
+ *
+ * Copyright (C) Volker Lendecke 2012
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include "includes.h"
+#include "system/filesys.h"
+#include "system/shmem.h"
+#include "smbd/smbd.h"
+#include "smbd/globals.h"
+#include "lib/util/tevent_unix.h"
+#include <aio.h>
+
+/* The signal we'll use to signify aio done. */
+#ifndef RT_SIGNAL_AIO
+#define RT_SIGNAL_AIO	(SIGRTMIN+3)
+#endif
+
+#ifndef HAVE_STRUCT_SIGEVENT_SIGEV_VALUE_SIVAL_PTR
+#ifdef HAVE_STRUCT_SIGEVENT_SIGEV_VALUE_SIGVAL_PTR
+#define sival_int	sigval_int
+#define sival_ptr	sigval_ptr
+#endif
+#endif
+
+static struct tevent_signal *aio_signal_event = NULL;
+
+struct aio_posix_state {
+	struct aiocb acb;
+	ssize_t ret;
+	int err;
+};
+
+static int aio_posix_state_destructor(struct aio_posix_state *s)
+{
+	int ret;
+
+	/*
+	 * We could do better here. This destructor is run when a
+	 * request is prematurely cancelled. We wait for the aio to
+	 * complete, so that we do not have to maintain aiocb structs
+	 * beyond the life of an aio_posix_state. Possible, but not
+	 * sure the effort is worth it right now.
+	 */
+
+	do {
+		const struct aiocb *a = &s->acb;
+		ret = aio_suspend(&a, 1, NULL);
+	} while ((ret == -1) && (errno == EINTR));
+
+	return 0;
+}
+
+static struct tevent_req *aio_posix_pread_send(
+	struct vfs_handle_struct *handle,
+	TALLOC_CTX *mem_ctx, struct tevent_context *ev,
+	struct files_struct *fsp, void *data, size_t n, off_t offset)
+{
+	struct tevent_req *req;
+	struct aio_posix_state *state;
+	struct aiocb *a;
+	int ret;
+
+	req = tevent_req_create(mem_ctx, &state, struct aio_posix_state);
+	if (req == NULL) {
+		return NULL;
+	}
+
+	a = &state->acb;
+
+	a->aio_fildes = fsp->fh->fd;
+	a->aio_buf = data;
+	a->aio_nbytes = n;
+	a->aio_offset = offset;
+	a->aio_sigevent.sigev_notify = SIGEV_SIGNAL;
+	a->aio_sigevent.sigev_signo  = RT_SIGNAL_AIO;
+	a->aio_sigevent.sigev_value.sival_ptr = req;
+
+	ret = aio_read(a);
+	if (ret == 0) {
+		talloc_set_destructor(state, aio_posix_state_destructor);
+		return req;
+	}
+
+	if (errno == EAGAIN) {
+		/*
+		 * aio overloaded, do the sync fallback
+		 */
+		state->ret = sys_pread(fsp->fh->fd, data, n, offset);
+		if (state->ret == -1) {
+			state->err = errno;
+		}
+		tevent_req_done(req);
+		return tevent_req_post(req, ev);
+	}
+
+	tevent_req_error(req, errno);
+	return tevent_req_post(req, ev);
+}
+
+static struct tevent_req *aio_posix_pwrite_send(
+	struct vfs_handle_struct *handle,
+	TALLOC_CTX *mem_ctx, struct tevent_context *ev,
+	struct files_struct *fsp, const void *data, size_t n, off_t offset)
+{
+	struct tevent_req *req;
+	struct aio_posix_state *state;
+	struct aiocb *a;
+	int ret;
+
+	req = tevent_req_create(mem_ctx, &state, struct aio_posix_state);
+	if (req == NULL) {
+		return NULL;
+	}
+
+	a = &state->acb;
+
+	a->aio_fildes = fsp->fh->fd;
+	a->aio_buf = discard_const(data);
+	a->aio_nbytes = n;
+	a->aio_offset = offset;
+	a->aio_sigevent.sigev_notify = SIGEV_SIGNAL;
+	a->aio_sigevent.sigev_signo  = RT_SIGNAL_AIO;
+	a->aio_sigevent.sigev_value.sival_ptr = req;
+
+	ret = aio_write(a);
+	if (ret == 0) {
+		talloc_set_destructor(state, aio_posix_state_destructor);
+		return req;
+	}
+
+	if (errno == EAGAIN) {
+		/*
+		 * aio overloaded, do the sync fallback
+		 */
+		state->ret = sys_pwrite(fsp->fh->fd, data, n, offset);
+		if (state->ret == -1) {
+			state->err = errno;
+		}
+		tevent_req_done(req);
+		return tevent_req_post(req, ev);
+	}
+
+	tevent_req_error(req, errno);
+	return tevent_req_post(req, ev);
+}
+
+static void aio_posix_signal_handler(struct tevent_context *ev,
+				     struct tevent_signal *se,
+				     int signum, int count,
+				     void *_info, void *private_data)
+{
+	siginfo_t *info;
+	struct tevent_req *req;
+	struct aio_posix_state *state;
+	int err;
+
+	info = (siginfo_t *)_info;
+	req = talloc_get_type_abort(info->si_value.sival_ptr,
+				    struct tevent_req);
+	state = tevent_req_data(req, struct aio_posix_state);
+
+	err = aio_error(&state->acb);
+	if (err == EINPROGRESS) {
+		DEBUG(10, ("aio_posix_signal_handler: operation req %p "
+			   "still in progress\n", req));
+		return;
+	}
+	if (err == ECANCELED) {
+		DEBUG(10, ("aio_posix_signal_handler: operation req %p "
+			   "canceled\n", req));
+		return;
+	}
+
+	/*
+	 * No need to suspend for this in the destructor anymore
+	 */
+	talloc_set_destructor(state, NULL);
+
+	state->ret = aio_return(&state->acb);
+	state->err = err;
+	tevent_req_done(req);
+}
+
+static ssize_t aio_posix_recv(struct tevent_req *req, int *err)
+{
+	struct aio_posix_state *state = tevent_req_data(
+		req, struct aio_posix_state);
+
+	if (tevent_req_is_unix_error(req, err)) {
+		return -1;
+	}
+	*err = state->err;
+	return state->ret;
+}
+
+static int aio_posix_connect(vfs_handle_struct *handle, const char *service,
+			     const char *user)
+{
+	if (aio_signal_event == NULL) {
+		struct tevent_context *ev = handle->conn->sconn->ev_ctx;
+
+		aio_signal_event = tevent_add_signal(
+			ev, ev, RT_SIGNAL_AIO, SA_SIGINFO,
+			aio_posix_signal_handler, NULL);
+
+		if (aio_signal_event == NULL) {
+			DEBUG(1, ("tevent_add_signal failed\n"));
+			return -1;
+		}
+	}
+	return SMB_VFS_NEXT_CONNECT(handle, service, user);
+}
+
+static struct vfs_fn_pointers vfs_aio_posix_fns = {
+	.connect_fn = aio_posix_connect,
+	.pread_send_fn = aio_posix_pread_send,
+	.pread_recv_fn = aio_posix_recv,
+	.pwrite_send_fn = aio_posix_pwrite_send,
+	.pwrite_recv_fn = aio_posix_recv,
+};
+
+NTSTATUS vfs_aio_posix_init(void);
+NTSTATUS vfs_aio_posix_init(void)
+{
+	return smb_register_vfs(SMB_VFS_INTERFACE_VERSION,
+				"aio_posix", &vfs_aio_posix_fns);
+}