1 files changed, 832 insertions, 0 deletions
diff --git a/source3/smbd/aio.c b/source3/smbd/aio.c
new file mode 100644
index 0000000000..74275368bd
--- /dev/null
+++ b/source3/smbd/aio.c
@@ -0,0 +1,832 @@
+/*
+   Unix SMB/Netbios implementation.
+   Version 3.0
+   async_io read handling using POSIX async io.
+   Copyright (C) Jeremy Allison 2005.
+
+   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, see <http://www.gnu.org/licenses/>.
+*/
+
+#include "includes.h"
+
+#if defined(WITH_AIO)
+
+/* The signal we'll use to signify aio done. */
+#ifndef RT_SIGNAL_AIO
+#define RT_SIGNAL_AIO (SIGRTMIN+3)
+#endif
+
+/****************************************************************************
+ The buffer we keep around whilst an aio request is in process.
+*****************************************************************************/
+
+struct aio_extra {
+	struct aio_extra *next, *prev;
+	SMB_STRUCT_AIOCB acb;
+	files_struct *fsp;
+	bool read_req;
+	uint16 mid;
+	char *inbuf;
+	char *outbuf;
+};
+
+static struct aio_extra *aio_list_head;
+
+/****************************************************************************
+ Create the extended aio struct we must keep around for the lifetime
+ of the aio_read call.
+*****************************************************************************/
+
+static struct aio_extra *create_aio_ex_read(files_struct *fsp, size_t buflen,
+					    uint16 mid)
+{
+	struct aio_extra *aio_ex = SMB_MALLOC_P(struct aio_extra);
+
+	if (!aio_ex) {
+		return NULL;
+	}
+	ZERO_STRUCTP(aio_ex);
+	/* The output buffer stored in the aio_ex is the start of
+	   the smb return buffer. The buffer used in the acb
+	   is the start of the reply data portion of that buffer. */
+	aio_ex->outbuf = SMB_MALLOC_ARRAY(char, buflen);
+	if (!aio_ex->outbuf) {
+		SAFE_FREE(aio_ex);
+		return NULL;
+	}
+	DLIST_ADD(aio_list_head, aio_ex);
+	aio_ex->fsp = fsp;
+	aio_ex->read_req = True;
+	aio_ex->mid = mid;
+	return aio_ex;
+}
+
+/****************************************************************************
+ Create the extended aio struct we must keep around for the lifetime
+ of the aio_write call.
+*****************************************************************************/
+
+static struct aio_extra *create_aio_ex_write(files_struct *fsp,
+					     size_t inbuflen,
+					     size_t outbuflen,
+					     uint16 mid)
+{
+	struct aio_extra *aio_ex = SMB_MALLOC_P(struct aio_extra);
+
+	if (!aio_ex) {
+		return NULL;
+	}
+	ZERO_STRUCTP(aio_ex);
+
+	/* We need space for an output reply of outbuflen bytes. */
+	aio_ex->outbuf = SMB_MALLOC_ARRAY(char, outbuflen);
+	if (!aio_ex->outbuf) {
+		SAFE_FREE(aio_ex);
+		return NULL;
+	}
+
+	if (!(aio_ex->inbuf = SMB_MALLOC_ARRAY(char, inbuflen))) {
+		SAFE_FREE(aio_ex->outbuf);
+		SAFE_FREE(aio_ex);
+		return NULL;
+	}
+
+	DLIST_ADD(aio_list_head, aio_ex);
+	aio_ex->fsp = fsp;
+	aio_ex->read_req = False;
+	aio_ex->mid = mid;
+	return aio_ex;
+}
+
+/****************************************************************************
+ Delete the extended aio struct.
+*****************************************************************************/
+
+static void delete_aio_ex(struct aio_extra *aio_ex)
+{
+	DLIST_REMOVE(aio_list_head, aio_ex);
+	SAFE_FREE(aio_ex->inbuf);
+	SAFE_FREE(aio_ex->outbuf);
+	SAFE_FREE(aio_ex);
+}
+
+/****************************************************************************
+ Given the aiocb struct find the extended aio struct containing it.
+*****************************************************************************/
+
+static struct aio_extra *find_aio_ex(uint16 mid)
+{
+	struct aio_extra *p;
+
+	for( p = aio_list_head; p; p = p->next) {
+		if (mid == p->mid) {
+			return p;
+		}
+	}
+	return NULL;
+}
+
+/****************************************************************************
+ We can have these many aio buffers in flight.
+*****************************************************************************/
+
+static int aio_pending_size;
+static sig_atomic_t signals_received;
+static int outstanding_aio_calls;
+static uint16 *aio_pending_array;
+
+/****************************************************************************
+ Signal handler when an aio request completes.
+*****************************************************************************/
+
+void aio_request_done(uint16_t mid)
+{
+	if (signals_received < aio_pending_size) {
+		aio_pending_array[signals_received] = mid;
+		signals_received++;
+	}
+	/* Else signal is lost. */
+}
+
+static void signal_handler(int sig, siginfo_t *info, void *unused)
+{
+	aio_request_done(info->si_value.sival_int);
+	sys_select_signal(RT_SIGNAL_AIO);
+}
+
+/****************************************************************************
+ Is there a signal waiting ?
+*****************************************************************************/
+
+bool aio_finished(void)
+{
+	return (signals_received != 0);
+}
+
+/****************************************************************************
+ Initialize the signal handler for aio read/write.
+*****************************************************************************/
+
+void initialize_async_io_handler(void)
+{
+	struct sigaction act;
+
+	aio_pending_size = lp_maxmux();
+	aio_pending_array = SMB_MALLOC_ARRAY(uint16, aio_pending_size);
+	SMB_ASSERT(aio_pending_array != NULL);
+
+	ZERO_STRUCT(act);
+	act.sa_sigaction = signal_handler;
+	act.sa_flags = SA_SIGINFO;
+	sigemptyset( &act.sa_mask );
+	if (sigaction(RT_SIGNAL_AIO, &act, NULL) != 0) {
+                DEBUG(0,("Failed to setup RT_SIGNAL_AIO handler\n"));
+        }
+
+	/* the signal can start off blocked due to a bug in bash */
+	BlockSignals(False, RT_SIGNAL_AIO);
+}
+
+/****************************************************************************
+ Set up an aio request from a SMBreadX call.
+*****************************************************************************/
+
+bool schedule_aio_read_and_X(connection_struct *conn,
+			     struct smb_request *req,
+			     files_struct *fsp, SMB_OFF_T startpos,
+			     size_t smb_maxcnt)
+{
+	struct aio_extra *aio_ex;
+	SMB_STRUCT_AIOCB *a;
+	size_t bufsize;
+	size_t min_aio_read_size = lp_aio_read_size(SNUM(conn));
+
+	if (fsp->base_fsp != NULL) {
+		/* No AIO on streams yet */
+		DEBUG(10, ("AIO on streams not yet supported\n"));
+		return false;
+	}
+
+	if ((!min_aio_read_size || (smb_maxcnt < min_aio_read_size))
+	    && !SMB_VFS_AIO_FORCE(fsp)) {
+		/* Too small a read for aio request. */
+		DEBUG(10,("schedule_aio_read_and_X: read size (%u) too small "
+			  "for minimum aio_read of %u\n",
+			  (unsigned int)smb_maxcnt,
+			  (unsigned int)min_aio_read_size ));
+		return False;
+	}
+
+	/* Only do this on non-chained and non-chaining reads not using the
+	 * write cache. */
+        if (chain_size !=0 || (CVAL(req->inbuf,smb_vwv0) != 0xFF)
+	    || (lp_write_cache_size(SNUM(conn)) != 0) ) {
+		return False;
+	}
+
+	if (outstanding_aio_calls >= aio_pending_size) {
+		DEBUG(10,("schedule_aio_read_and_X: Already have %d aio "
+			  "activities outstanding.\n",
+			  outstanding_aio_calls ));
+		return False;
+	}
+
+	/* The following is safe from integer wrap as we've already checked
+	   smb_maxcnt is 128k or less. Wct is 12 for read replies */
+
+	bufsize = smb_size + 12 * 2 + smb_maxcnt;
+
+	if ((aio_ex = create_aio_ex_read(fsp, bufsize, req->mid)) == NULL) {
+		DEBUG(10,("schedule_aio_read_and_X: malloc fail.\n"));
+		return False;
+	}
+
+	construct_reply_common((char *)req->inbuf, aio_ex->outbuf);
+	srv_set_message(aio_ex->outbuf, 12, 0, True);
+	SCVAL(aio_ex->outbuf,smb_vwv0,0xFF); /* Never a chained reply. */
+
+	a = &aio_ex->acb;
+
+	/* Now set up the aio record for the read call. */
+	
+	a->aio_fildes = fsp->fh->fd;
+	a->aio_buf = smb_buf(aio_ex->outbuf);
+	a->aio_nbytes = smb_maxcnt;
+	a->aio_offset = startpos;
+	a->aio_sigevent.sigev_notify = SIGEV_SIGNAL;
+	a->aio_sigevent.sigev_signo  = RT_SIGNAL_AIO;
+	a->aio_sigevent.sigev_value.sival_int = aio_ex->mid;
+
+	become_root();
+	if (SMB_VFS_AIO_READ(fsp,a) == -1) {
+		DEBUG(0,("schedule_aio_read_and_X: aio_read failed. "
+			 "Error %s\n", strerror(errno) ));
+		delete_aio_ex(aio_ex);
+		unbecome_root();
+		return False;
+	}
+	unbecome_root();
+
+	DEBUG(10,("schedule_aio_read_and_X: scheduled aio_read for file %s, "
+		  "offset %.0f, len = %u (mid = %u)\n",
+		  fsp->fsp_name, (double)startpos, (unsigned int)smb_maxcnt,
+		  (unsigned int)aio_ex->mid ));
+
+	srv_defer_sign_response(aio_ex->mid);
+	outstanding_aio_calls++;
+	return True;
+}
+
+/****************************************************************************
+ Set up an aio request from a SMBwriteX call.
+*****************************************************************************/
+
+bool schedule_aio_write_and_X(connection_struct *conn,
+			      struct smb_request *req,
+			      files_struct *fsp, char *data,
+			      SMB_OFF_T startpos,
+			      size_t numtowrite)
+{
+	struct aio_extra *aio_ex;
+	SMB_STRUCT_AIOCB *a;
+	size_t inbufsize, outbufsize;
+	bool write_through = BITSETW(req->inbuf+smb_vwv7,0);
+	size_t min_aio_write_size = lp_aio_write_size(SNUM(conn));
+
+	if (fsp->base_fsp != NULL) {
+		/* No AIO on streams yet */
+		DEBUG(10, ("AIO on streams not yet supported\n"));
+		return false;
+	}
+
+	if ((!min_aio_write_size || (numtowrite < min_aio_write_size))
+	    && !SMB_VFS_AIO_FORCE(fsp)) {
+		/* Too small a write for aio request. */
+		DEBUG(10,("schedule_aio_write_and_X: write size (%u) too "
+			  "small for minimum aio_write of %u\n",
+			  (unsigned int)numtowrite,
+			  (unsigned int)min_aio_write_size ));
+		return False;
+	}
+
+	/* Only do this on non-chained and non-chaining reads not using the
+	 * write cache. */
+        if (chain_size !=0 || (CVAL(req->inbuf,smb_vwv0) != 0xFF)
+	    || (lp_write_cache_size(SNUM(conn)) != 0) ) {
+		return False;
+	}
+
+	if (outstanding_aio_calls >= aio_pending_size) {
+		DEBUG(3,("schedule_aio_write_and_X: Already have %d aio "
+			 "activities outstanding.\n",
+			  outstanding_aio_calls ));
+		DEBUG(10,("schedule_aio_write_and_X: failed to schedule "
+			  "aio_write for file %s, offset %.0f, len = %u "
+			  "(mid = %u)\n",
+			  fsp->fsp_name, (double)startpos,
+			  (unsigned int)numtowrite,
+			  (unsigned int)req->mid ));
+		return False;
+	}
+
+	inbufsize =  smb_len(req->inbuf) + 4;
+	reply_outbuf(req, 6, 0);
+	outbufsize = smb_len(req->outbuf) + 4;
+	if (!(aio_ex = create_aio_ex_write(fsp, inbufsize, outbufsize,
+					   req->mid))) {
+		DEBUG(0,("schedule_aio_write_and_X: malloc fail.\n"));
+		return False;
+	}
+
+	/* Copy the SMB header already setup in outbuf. */
+	memcpy(aio_ex->inbuf, req->inbuf, inbufsize);
+
+	/* Copy the SMB header already setup in outbuf. */
+	memcpy(aio_ex->outbuf, req->outbuf, outbufsize);
+	TALLOC_FREE(req->outbuf);
+	SCVAL(aio_ex->outbuf,smb_vwv0,0xFF); /* Never a chained reply. */
+
+	a = &aio_ex->acb;
+
+	/* Now set up the aio record for the write call. */
+	
+	a->aio_fildes = fsp->fh->fd;
+	a->aio_buf = aio_ex->inbuf + (PTR_DIFF(data, req->inbuf));
+	a->aio_nbytes = numtowrite;
+	a->aio_offset = startpos;
+	a->aio_sigevent.sigev_notify = SIGEV_SIGNAL;
+	a->aio_sigevent.sigev_signo  = RT_SIGNAL_AIO;
+	a->aio_sigevent.sigev_value.sival_int = aio_ex->mid;
+
+	become_root();
+	if (SMB_VFS_AIO_WRITE(fsp,a) == -1) {
+		DEBUG(3,("schedule_aio_wrote_and_X: aio_write failed. "
+			 "Error %s\n", strerror(errno) ));
+		delete_aio_ex(aio_ex);
+		unbecome_root();
+		return False;
+	}
+	unbecome_root();
+	
+	release_level_2_oplocks_on_change(fsp);
+
+	if (!write_through && !lp_syncalways(SNUM(fsp->conn))
+	    && fsp->aio_write_behind) {
+		/* Lie to the client and immediately claim we finished the
+		 * write. */
+	        SSVAL(aio_ex->outbuf,smb_vwv2,numtowrite);
+                SSVAL(aio_ex->outbuf,smb_vwv4,(numtowrite>>16)&1);
+		show_msg(aio_ex->outbuf);
+		if (!srv_send_smb(smbd_server_fd(),aio_ex->outbuf,
+				IS_CONN_ENCRYPTED(fsp->conn))) {
+			exit_server_cleanly("handle_aio_write: srv_send_smb "
+					    "failed.");
+		}
+		DEBUG(10,("schedule_aio_write_and_X: scheduled aio_write "
+			  "behind for file %s\n", fsp->fsp_name ));
+	} else {
+		srv_defer_sign_response(aio_ex->mid);
+	}
+	outstanding_aio_calls++;
+
+	DEBUG(10,("schedule_aio_write_and_X: scheduled aio_write for file "
+		  "%s, offset %.0f, len = %u (mid = %u) "
+		  "outstanding_aio_calls = %d\n",
+		  fsp->fsp_name, (double)startpos, (unsigned int)numtowrite,
+		  (unsigned int)aio_ex->mid, outstanding_aio_calls ));
+
+	return True;
+}
+
+
+/****************************************************************************
+ Complete the read and return the data or error back to the client.
+ Returns errno or zero if all ok.
+*****************************************************************************/
+
+static int handle_aio_read_complete(struct aio_extra *aio_ex)
+{
+	int ret = 0;
+	int outsize;
+	char *outbuf = aio_ex->outbuf;
+	char *data = smb_buf(outbuf);
+	ssize_t nread = SMB_VFS_AIO_RETURN(aio_ex->fsp,&aio_ex->acb);
+
+	if (nread < 0) {
+		/* We're relying here on the fact that if the fd is
+		   closed then the aio will complete and aio_return
+		   will return an error. Hopefully this is
+		   true.... JRA. */
+
+		/* If errno is ECANCELED then don't return anything to the
+		 * client. */
+		if (errno == ECANCELED) {
+			srv_cancel_sign_response(aio_ex->mid);
+			return 0;
+		}
+
+		DEBUG( 3,( "handle_aio_read_complete: file %s nread == -1. "
+			   "Error = %s\n",
+			   aio_ex->fsp->fsp_name, strerror(errno) ));
+
+		ret = errno;
+		ERROR_NT(map_nt_error_from_unix(ret));
+		outsize = srv_set_message(outbuf,0,0,true);
+	} else {
+		outsize = srv_set_message(outbuf,12,nread,False);
+		SSVAL(outbuf,smb_vwv2,0xFFFF); /* Remaining - must be * -1. */
+		SSVAL(outbuf,smb_vwv5,nread);
+		SSVAL(outbuf,smb_vwv6,smb_offset(data,outbuf));
+		SSVAL(outbuf,smb_vwv7,((nread >> 16) & 1));
+		SSVAL(smb_buf(outbuf),-2,nread);
+
+		aio_ex->fsp->fh->pos = aio_ex->acb.aio_offset + nread;
+		aio_ex->fsp->fh->position_information = aio_ex->fsp->fh->pos;
+
+		DEBUG( 3, ( "handle_aio_read_complete file %s max=%d "
+			    "nread=%d\n",
+			    aio_ex->fsp->fsp_name,
+			    (int)aio_ex->acb.aio_nbytes, (int)nread ) );
+
+	}
+	smb_setlen(outbuf,outsize - 4);
+	show_msg(outbuf);
+	if (!srv_send_smb(smbd_server_fd(),outbuf,
+			IS_CONN_ENCRYPTED(aio_ex->fsp->conn))) {
+		exit_server_cleanly("handle_aio_read_complete: srv_send_smb "
+				    "failed.");
+	}
+
+	DEBUG(10,("handle_aio_read_complete: scheduled aio_read completed "
+		  "for file %s, offset %.0f, len = %u\n",
+		  aio_ex->fsp->fsp_name, (double)aio_ex->acb.aio_offset,
+		  (unsigned int)nread ));
+
+	return ret;
+}
+
+/****************************************************************************
+ Complete the write and return the data or error back to the client.
+ Returns errno or zero if all ok.
+*****************************************************************************/
+
+static int handle_aio_write_complete(struct aio_extra *aio_ex)
+{
+	int ret = 0;
+	files_struct *fsp = aio_ex->fsp;
+	char *outbuf = aio_ex->outbuf;
+	ssize_t numtowrite = aio_ex->acb.aio_nbytes;
+	ssize_t nwritten = SMB_VFS_AIO_RETURN(fsp,&aio_ex->acb);
+
+	if (fsp->aio_write_behind) {
+		if (nwritten != numtowrite) {
+			if (nwritten == -1) {
+				DEBUG(5,("handle_aio_write_complete: "
+					 "aio_write_behind failed ! File %s "
+					 "is corrupt ! Error %s\n",
+					 fsp->fsp_name, strerror(errno) ));
+				ret = errno;
+			} else {
+				DEBUG(0,("handle_aio_write_complete: "
+					 "aio_write_behind failed ! File %s "
+					 "is corrupt ! Wanted %u bytes but "
+					 "only wrote %d\n", fsp->fsp_name,
+					 (unsigned int)numtowrite,
+					 (int)nwritten ));
+				ret = EIO;
+			}
+		} else {
+			DEBUG(10,("handle_aio_write_complete: "
+				  "aio_write_behind completed for file %s\n",
+				  fsp->fsp_name ));
+		}
+		return 0;
+	}
+
+	/* We don't need outsize or set_message here as we've already set the
+	   fixed size length when we set up the aio call. */
+
+	if(nwritten == -1) {
+		DEBUG( 3,( "handle_aio_write: file %s wanted %u bytes. "
+			   "nwritten == %d. Error = %s\n",
+			   fsp->fsp_name, (unsigned int)numtowrite,
+			   (int)nwritten, strerror(errno) ));
+
+		/* If errno is ECANCELED then don't return anything to the
+		 * client. */
+		if (errno == ECANCELED) {
+			srv_cancel_sign_response(aio_ex->mid);
+			return 0;
+		}
+
+		ret = errno;
+		ERROR_BOTH(map_nt_error_from_unix(ret), ERRHRD, ERRdiskfull);
+		srv_set_message(outbuf,0,0,true);
+        } else {
+		bool write_through = BITSETW(aio_ex->inbuf+smb_vwv7,0);
+		NTSTATUS status;
+
+        	SSVAL(outbuf,smb_vwv2,nwritten);
+		SSVAL(outbuf,smb_vwv4,(nwritten>>16)&1);
+		if (nwritten < (ssize_t)numtowrite) {
+			SCVAL(outbuf,smb_rcls,ERRHRD);
+			SSVAL(outbuf,smb_err,ERRdiskfull);
+		}
+
+		DEBUG(3,("handle_aio_write: fnum=%d num=%d wrote=%d\n",
+			 fsp->fnum, (int)numtowrite, (int)nwritten));
+		status = sync_file(fsp->conn,fsp, write_through);
+		if (!NT_STATUS_IS_OK(status)) {
+			ret = errno;
+			ERROR_BOTH(map_nt_error_from_unix(ret),
+				   ERRHRD, ERRdiskfull);
+			srv_set_message(outbuf,0,0,true);
+                	DEBUG(5,("handle_aio_write: sync_file for %s returned %s\n",
+				fsp->fsp_name, nt_errstr(status) ));
+		}
+
+		aio_ex->fsp->fh->pos = aio_ex->acb.aio_offset + nwritten;
+	}
+
+	show_msg(outbuf);
+	if (!srv_send_smb(smbd_server_fd(),outbuf,IS_CONN_ENCRYPTED(fsp->conn))) {
+		exit_server_cleanly("handle_aio_write: srv_send_smb failed.");
+	}
+
+	DEBUG(10,("handle_aio_write_complete: scheduled aio_write completed "
+		  "for file %s, offset %.0f, requested %u, written = %u\n",
+		  fsp->fsp_name, (double)aio_ex->acb.aio_offset,
+		  (unsigned int)numtowrite, (unsigned int)nwritten ));
+
+	return ret;
+}
+
+/****************************************************************************
+ Handle any aio completion. Returns True if finished (and sets *perr if err
+ was non-zero), False if not.
+*****************************************************************************/
+
+static bool handle_aio_completed(struct aio_extra *aio_ex, int *perr)
+{
+	int err;
+
+	/* Ensure the operation has really completed. */
+	if (SMB_VFS_AIO_ERROR(aio_ex->fsp, &aio_ex->acb) == EINPROGRESS) {
+		DEBUG(10,( "handle_aio_completed: operation mid %u still in "
+			   "process for file %s\n",
+			   aio_ex->mid, aio_ex->fsp->fsp_name ));
+		return False;
+	}
+
+	if (aio_ex->read_req) {
+		err = handle_aio_read_complete(aio_ex);
+	} else {
+		err = handle_aio_write_complete(aio_ex);
+	}
+
+	if (err) {
+		*perr = err; /* Only save non-zero errors. */
+	}
+
+	return True;
+}
+
+/****************************************************************************
+ Handle any aio completion inline.
+ Returns non-zero errno if fail or zero if all ok.
+*****************************************************************************/
+
+int process_aio_queue(void)
+{
+	int i;
+	int ret = 0;
+
+	BlockSignals(True, RT_SIGNAL_AIO);
+
+	DEBUG(10,("process_aio_queue: signals_received = %d\n",
+		  (int)signals_received));
+	DEBUG(10,("process_aio_queue: outstanding_aio_calls = %d\n",
+		  outstanding_aio_calls));
+
+	if (!signals_received) {
+		BlockSignals(False, RT_SIGNAL_AIO);
+		return 0;
+	}
+
+	/* Drain all the complete aio_reads. */
+	for (i = 0; i < signals_received; i++) {
+		uint16 mid = aio_pending_array[i];
+		files_struct *fsp = NULL;
+		struct aio_extra *aio_ex = find_aio_ex(mid);
+
+		if (!aio_ex) {
+			DEBUG(3,("process_aio_queue: Can't find record to "
+				 "match mid %u.\n", (unsigned int)mid));
+			srv_cancel_sign_response(mid);
+			continue;
+		}
+
+		fsp = aio_ex->fsp;
+		if (fsp == NULL) {
+			/* file was closed whilst I/O was outstanding. Just
+			 * ignore. */
+			DEBUG( 3,( "process_aio_queue: file closed whilst "
+				   "aio outstanding.\n"));
+			srv_cancel_sign_response(mid);
+			continue;
+		}
+
+		if (!handle_aio_completed(aio_ex, &ret)) {
+			continue;
+		}
+
+		delete_aio_ex(aio_ex);
+	}
+
+	outstanding_aio_calls -= signals_received;
+	signals_received = 0;
+	BlockSignals(False, RT_SIGNAL_AIO);
+	return ret;
+}
+
+/****************************************************************************
+ We're doing write behind and the client closed the file. Wait up to 30
+ seconds (my arbitrary choice) for the aio to complete. Return 0 if all writes
+ completed, errno to return if not.
+*****************************************************************************/
+
+#define SMB_TIME_FOR_AIO_COMPLETE_WAIT 29
+
+int wait_for_aio_completion(files_struct *fsp)
+{
+	struct aio_extra *aio_ex;
+	const SMB_STRUCT_AIOCB **aiocb_list;
+	int aio_completion_count = 0;
+	time_t start_time = time(NULL);
+	int seconds_left;
+
+	for (seconds_left = SMB_TIME_FOR_AIO_COMPLETE_WAIT;
+	     seconds_left >= 0;) {
+		int err = 0;
+		int i;
+		struct timespec ts;
+
+		aio_completion_count = 0;
+		for( aio_ex = aio_list_head; aio_ex; aio_ex = aio_ex->next) {
+			if (aio_ex->fsp == fsp) {
+				aio_completion_count++;
+			}
+		}
+
+		if (!aio_completion_count) {
+			return 0;
+		}
+
+		DEBUG(3,("wait_for_aio_completion: waiting for %d aio events "
+			 "to complete.\n", aio_completion_count ));
+
+		aiocb_list = SMB_MALLOC_ARRAY(const SMB_STRUCT_AIOCB *,
+					      aio_completion_count);
+		if (!aiocb_list) {
+			return ENOMEM;
+		}
+
+		for( i = 0, aio_ex = aio_list_head;
+		     aio_ex;
+		     aio_ex = aio_ex->next) {
+			if (aio_ex->fsp == fsp) {
+				aiocb_list[i++] = &aio_ex->acb;
+			}
+		}
+
+		/* Now wait up to seconds_left for completion. */
+		ts.tv_sec = seconds_left;
+		ts.tv_nsec = 0;
+
+		DEBUG(10,("wait_for_aio_completion: %d events, doing a wait "
+			  "of %d seconds.\n",
+			  aio_completion_count, seconds_left ));
+
+		err = SMB_VFS_AIO_SUSPEND(fsp, aiocb_list,
+					  aio_completion_count, &ts);
+
+		DEBUG(10,("wait_for_aio_completion: returned err = %d, "
+			  "errno = %s\n", err, strerror(errno) ));
+		
+		if (err == -1 && errno == EAGAIN) {
+			DEBUG(0,("wait_for_aio_completion: aio_suspend timed "
+				 "out waiting for %d events after a wait of "
+				 "%d seconds\n", aio_completion_count,
+				 seconds_left));
+			/* Timeout. */
+			cancel_aio_by_fsp(fsp);
+			SAFE_FREE(aiocb_list);
+			return EIO;
+		}
+
+		/* One or more events might have completed - process them if
+		 * so. */
+		for( i = 0; i < aio_completion_count; i++) {
+			uint16 mid = aiocb_list[i]->aio_sigevent.sigev_value.sival_int;
+
+			aio_ex = find_aio_ex(mid);
+
+			if (!aio_ex) {
+				DEBUG(0, ("wait_for_aio_completion: mid %u "
+					  "doesn't match an aio record\n",
+					  (unsigned int)mid ));
+				continue;
+			}
+
+			if (!handle_aio_completed(aio_ex, &err)) {
+				continue;
+			}
+			delete_aio_ex(aio_ex);
+		}
+
+		SAFE_FREE(aiocb_list);
+		seconds_left = SMB_TIME_FOR_AIO_COMPLETE_WAIT
+			- (time(NULL) - start_time);
+	}
+
+	/* We timed out - we don't know why. Return ret if already an error,
+	 * else EIO. */
+	DEBUG(10,("wait_for_aio_completion: aio_suspend timed out waiting "
+		  "for %d events\n",
+		  aio_completion_count));
+
+	return EIO;
+}
+
+/****************************************************************************
+ Cancel any outstanding aio requests. The client doesn't care about the reply.
+*****************************************************************************/
+
+void cancel_aio_by_fsp(files_struct *fsp)
+{
+	struct aio_extra *aio_ex;
+
+	for( aio_ex = aio_list_head; aio_ex; aio_ex = aio_ex->next) {
+		if (aio_ex->fsp == fsp) {
+			/* Don't delete the aio_extra record as we may have
+			   completed and don't yet know it. Just do the
+			   aio_cancel call and return. */
+			SMB_VFS_AIO_CANCEL(fsp, &aio_ex->acb);
+			aio_ex->fsp = NULL; /* fsp will be closed when we
+					     * return. */
+		}
+	}
+}
+
+#else
+bool aio_finished(void)
+{
+	return False;
+}
+
+void initialize_async_io_handler(void)
+{
+}
+
+int process_aio_queue(void)
+{
+	return False;
+}
+
+bool schedule_aio_read_and_X(connection_struct *conn,
+			     struct smb_request *req,
+			     files_struct *fsp, SMB_OFF_T startpos,
+			     size_t smb_maxcnt)
+{
+	return False;
+}
+
+bool schedule_aio_write_and_X(connection_struct *conn,
+			      struct smb_request *req,
+			      files_struct *fsp, char *data,
+			      SMB_OFF_T startpos,
+			      size_t numtowrite)
+{
+	return False;
+}
+
+void cancel_aio_by_fsp(files_struct *fsp)
+{
+}
+
+int wait_for_aio_completion(files_struct *fsp)
+{
+	return ENOSYS;
+}
+#endif