From: Art Cancro <ajc@citadel.org>
Date: Sun, 21 Mar 2004 22:32:24 +0000 (+0000)
Subject: * room_ops.c: increased the thread safety of cgetfloor()
X-Git-Tag: v7.86~5513
X-Git-Url: https://code.citadel.org/?a=commitdiff_plain;h=4f17bebc9e09e72864ad64b0677bf526c9cb5cd9;p=citadel.git

* room_ops.c: increased the thread safety of cgetfloor()
* housekeeping.c: check floor reference counts in two passes instead of
  trying to manipulate multiple tables in O^2
---

diff --git a/citadel/ChangeLog b/citadel/ChangeLog
index 8f8749044..90c622f90 100644
--- a/citadel/ChangeLog
+++ b/citadel/ChangeLog
@@ -1,4 +1,9 @@
  $Log$
+ Revision 614.90  2004/03/21 22:32:24  ajc
+ * room_ops.c: increased the thread safety of cgetfloor()
+ * housekeeping.c: check floor reference counts in two passes instead of
+   trying to manipulate multiple tables in O^2
+
  Revision 614.89  2004/03/21 17:14:46  error
  * stress.c: Fixed.  Now properly spawns threads and stresses out your
    favorite Citadel server by simulating large numbers of really active
@@ -5565,3 +5570,4 @@ Sat Jul 11 00:20:48 EDT 1998 Nathan Bryant <bryant@cs.usm.maine.edu>
 
 Fri Jul 10 1998 Art Cancro <ajc@uncensored.citadel.org>
 	* Initial CVS import
+
diff --git a/citadel/housekeeping.c b/citadel/housekeeping.c
index c60bcbf94..da86e19c3 100644
--- a/citadel/housekeeping.c
+++ b/citadel/housekeeping.c
@@ -90,33 +90,43 @@ void check_sched_shutdown(void) {
 /*
  * Check (and fix) floor reference counts.  This doesn't need to be done
  * very often, since the counts should remain correct during normal operation.
- * NOTE: this function pair should ONLY be called during startup.  It is NOT
- * thread safe.
  */
 void check_ref_counts_backend(struct ctdlroom *qrbuf, void *data) {
-	struct floor flbuf;
 
-	getfloor(&flbuf, qrbuf->QRfloor);
-	++flbuf.f_ref_count;
-	flbuf.f_flags = flbuf.f_flags | QR_INUSE;
-	putfloor(&flbuf, qrbuf->QRfloor);
+	int *new_refcounts;
+
+	new_refcounts = (int *) data;
+
+	++new_refcounts[(int)qrbuf->QRfloor];
 }
 
 void check_ref_counts(void) {
 	struct floor flbuf;
 	int a;
 
+	int new_refcounts[MAXFLOORS];
+
 	lprintf(CTDL_DEBUG, "Checking floor reference counts\n");
 	for (a=0; a<MAXFLOORS; ++a) {
-		getfloor(&flbuf, a);
-		flbuf.f_ref_count = 0;
-		flbuf.f_flags = flbuf.f_flags & ~QR_INUSE;
-		putfloor(&flbuf, a);
+		new_refcounts[a] = 0;
 	}
 
 	cdb_begin_transaction();
-	ForEachRoom(check_ref_counts_backend, NULL);
+	ForEachRoom(check_ref_counts_backend, (void *)new_refcounts );
 	cdb_end_transaction();
+
+	for (a=0; a<MAXFLOORS; ++a) {
+		lgetfloor(&flbuf, a);
+		flbuf.f_ref_count = new_refcounts[a];
+		if (new_refcounts[a] > 0) {
+			flbuf.f_flags = flbuf.f_flags | QR_INUSE;
+		}
+		else {
+			flbuf.f_flags = flbuf.f_flags & ~QR_INUSE;
+		}
+		lputfloor(&flbuf, a);
+		lprintf(9, "Floor %d: %d rooms\n", a, new_refcounts[a]);
+	}
 }	
 
 /*
diff --git a/citadel/room_ops.c b/citadel/room_ops.c
index 2b80cabae..242025627 100644
--- a/citadel/room_ops.c
+++ b/citadel/room_ops.c
@@ -333,17 +333,31 @@ void lgetfloor(struct floor *flbuf, int floor_num)
 struct floor *cgetfloor(int floor_num) {
 	static int initialized = 0;
 	int i;
+	int fetch_new = 0;
+	struct floor *fl = NULL;
 
+	begin_critical_section(S_FLOORCACHE);
 	if (initialized == 0) {
 		for (i=0; i<MAXFLOORS; ++i) {
 			floorcache[floor_num] = NULL;
 		}
 	initialized = 1;
 	}
-	
 	if (floorcache[floor_num] == NULL) {
-		floorcache[floor_num] = mallok(sizeof(struct floor));
-		getfloor(floorcache[floor_num], floor_num);
+		fetch_new = 1;
+	}
+	end_critical_section(S_FLOORCACHE);
+
+	if (fetch_new) {
+		lprintf(9, "fetch_new is active ... going to disk\n");
+		fl = mallok(sizeof(struct floor));
+		getfloor(fl, floor_num);
+		begin_critical_section(S_FLOORCACHE);
+		if (floorcache[floor_num] != NULL) {
+			phree(floorcache[floor_num]);
+		}
+		floorcache[floor_num] = fl;
+		end_critical_section(S_FLOORCACHE);
 	}
 
 	return(floorcache[floor_num]);
@@ -356,14 +370,17 @@ struct floor *cgetfloor(int floor_num) {
  */
 void putfloor(struct floor *flbuf, int floor_num)
 {
-	cdb_store(CDB_FLOORTAB, &floor_num, sizeof(int),
-		  flbuf, sizeof(struct floor));
-
 	/* If we've cached this, clear it out, 'cuz it's WRONG now! */
+	begin_critical_section(S_FLOORCACHE);
 	if (floorcache[floor_num] != NULL) {
 		phree(floorcache[floor_num]);
-		floorcache[floor_num] = NULL;
+		floorcache[floor_num] = mallok(sizeof(struct floor));
+		memcpy(floorcache[floor_num], flbuf, sizeof(struct floor));
 	}
+	end_critical_section(S_FLOORCACHE);
+
+	cdb_store(CDB_FLOORTAB, &floor_num, sizeof(int),
+		  flbuf, sizeof(struct floor));
 }
 
 
@@ -1692,7 +1709,12 @@ void cmd_cre8(char *args)
 
 	if (num_parms(args) >= 5) {
 		fl = cgetfloor(extract_int(args, 4));
-		if ((fl->f_flags & F_INUSE) == 0) {
+		if (fl == NULL) {
+			cprintf("%d Invalid floor number.\n",
+				ERROR + INVALID_FLOOR_OPERATION);
+			return;
+		}
+		else if ((fl->f_flags & F_INUSE) == 0) {
 			cprintf("%d Invalid floor number.\n",
 				ERROR + INVALID_FLOOR_OPERATION);
 			return;
diff --git a/citadel/server.h b/citadel/server.h
index c72f849f1..8c42ec21c 100644
--- a/citadel/server.h
+++ b/citadel/server.h
@@ -215,6 +215,7 @@ enum {
 	S_NETCONFIGS,
 	S_PUBLIC_CLIENTS,
 	S_LDAP,
+	S_FLOORCACHE,
 	MAX_SEMAPHORES
 };