From dd59d50944d116b0a5eaaf8941f08e1e469be1b0 Mon Sep 17 00:00:00 2001
From: Ben Gras <ben@minix3.org>
Date: Fri, 13 Jan 2012 16:05:32 +0100
Subject: [PATCH] mfs: mark blocks clean when invalidated

	. it could happen that newly filled blocks were still marked
	  dirty
	. causing unnecessary i/o and the new warning of the superblock
	  being written
---
 servers/mfs/cache.c | 17 +++++++++--------
 servers/mfs/clean.h |  3 +++
 2 files changed, 12 insertions(+), 8 deletions(-)

diff --git a/servers/mfs/cache.c b/servers/mfs/cache.c
index 89b81b321..d64dcc228 100644
--- a/servers/mfs/cache.c
+++ b/servers/mfs/cache.c
@@ -145,11 +145,12 @@ PUBLIC struct buf *get_block(
 	 */
 	yieldid = make64(bp->b_dev, bp->b_blocknr);
 	assert(bp->b_bytes == fs_block_size);
-	bp->b_dev = NO_DEV;
+	BP_CLEARDEV(bp);
   }
 
   /* Fill in block's parameters and add it to the hash chain where it goes. */
-  bp->b_dev = dev;		/* fill in device number */
+  if(dev == NO_DEV) BP_CLEARDEV(bp);
+  else BP_SETDEV(bp, dev);
   bp->b_blocknr = block;	/* fill in block number */
   bp->b_count++;		/* record that block is being used */
   b = BUFHASH(bp->b_blocknr);
@@ -183,7 +184,7 @@ PUBLIC struct buf *get_block(
 
   if(only_search == PREFETCH) {
 	/* PREFETCH: don't do i/o. */
-	bp->b_dev = NO_DEV;
+	BP_CLEARDEV(bp);
   } else if (only_search == NORMAL) {
 	read_block(bp);
   } else if(only_search == NO_READ) {
@@ -350,7 +351,7 @@ register struct buf *bp;	/* buffer pointer */
 	}
 
 	if (op_failed) {
-		bp->b_dev = NO_DEV;	/* invalidate block */
+		BP_CLEARDEV(bp);	/* invalidate block */
 
 		/* Report read errors to interested parties. */
 		rdwt_err = r;
@@ -370,7 +371,7 @@ PUBLIC void invalidate(
   register struct buf *bp;
 
   for (bp = &buf[0]; bp < &buf[nr_bufs]; bp++)
-	if (bp->b_dev == device) bp->b_dev = NO_DEV;
+	if (bp->b_dev == device) BP_CLEARDEV(bp);
 
   vm_forgetblocks();
 }
@@ -501,13 +502,13 @@ PUBLIC void rw_scattered(
 		if (r < (ssize_t) fs_block_size) {
 			/* Transfer failed. */
 			if (i == 0) {
-				bp->b_dev = NO_DEV;	/* Invalidate block */
+				BP_CLEARDEV(bp);	/* Invalidate block */
 				vm_forgetblocks();
 			}
 			break;
 		}
 		if (rw_flag == READING) {
-			bp->b_dev = dev;	/* validate block */
+			BP_SETDEV(bp, dev);	/* validate block */
 			put_block(bp, PARTIAL_DATA_BLOCK);
 		} else {
 			MARKCLEAN(bp);
@@ -662,7 +663,7 @@ PUBLIC void buf_pool(int new_nr_bufs)
 
   for (bp = &buf[0]; bp < &buf[nr_bufs]; bp++) {
         bp->b_blocknr = NO_BLOCK;
-        bp->b_dev = NO_DEV;
+	BP_CLEARDEV(bp);
         bp->b_next = bp + 1;
         bp->b_prev = bp - 1;
         bp->bp = NULL;
diff --git a/servers/mfs/clean.h b/servers/mfs/clean.h
index 626c7acec..d6d112985 100644
--- a/servers/mfs/clean.h
+++ b/servers/mfs/clean.h
@@ -8,4 +8,7 @@
 #define ISDIRTY(b)	((b)->b_dirt == BP_DIRTY)
 #define ISCLEAN(b)	((b)->b_dirt == BP_CLEAN)
 
+#define BP_SETDEV(b, dev) do { assert((dev) != NO_DEV); (b)->b_dev = (dev); } while(0)
+#define BP_CLEARDEV(b) do { (b)->b_dev = NO_DEV; MARKCLEAN(b); } while(0)
+
 #endif
-- 
2.44.0