code: mafs

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jumbo writes

--- a/dev.c

+++ b/dev.c

@@ -31,13 +31,19 @@

 }

 int

-devwrite(u64 blkno, void *b)

+devwrites(u64 blkno, void *b, u64 n)

 {

-	int n;

+	int wn;

-	if((n = pwrite(devfd, b, Rawblocksize, blkno*Rawblocksize)) != Rawblocksize)

+	if((wn = pwrite(devfd, b, n*Rawblocksize, blkno*Rawblocksize)) != n*Rawblocksize)

 		panic("devwrite failed: %r\n");

-	return n;

+	return wn;

+}

+

+int

+devwrite(u64 blkno, void *b)

+{

+	return devwrites(blkno, b, 1);

 }

 /* obsoleted, a hack for more efficient logging */

--- a/docs/mafs.ms

+++ b/docs/mafs.ms

@@ -1182,25 +1182,20 @@

 .fi

 .sp

 Starting mafs on a 2MB byte file. The below commands create a disk.file to use as a disk. Mount /n/mafs_disk.file for the file system.

-.nf

 .sp

+.nf

 	dd -if /dev/zero -of disk.file -bs 512 -count 4096;

-.br

 	mount -c <{disk/mafs -s -r mafs_disk.file -m 1 -n mafs_disk.file \\

 		  <[0=1]} /n/mafs_disk.file

 .fi

 .sp

 Starting mafs on a RAM file. The below commands create a ramfs filesystem to use as a disk.

-.nf

 .sp

+.nf

 	ramfs -m /n/mafs_ramfs

-.br

 	touch /n/mafs_ramfs/file

-.br

 	dd -if /dev/zero -of /n/mafs_ramfs/file -count 700 -bs 1m

-.br

 	disk/mafs -r mafs_ramfs_file /n/mafs_ramfs/file

-.br

 	mount -c /srv/mafs_ramfs_file /n/mafs_ramfs_file

 .fi

 .sp

--- a/fns.h

+++ b/fns.h

@@ -11,6 +11,7 @@

 int	devread(u64 blkno, void *b);

 u64	devsize(void);

 int	devwrite(u64 blkno, void *b);

+int	devwrites(u64 blkno, void *b, u64 n);

 /* show blocks */

 void	showblock(int fd, u8 *buf);

--- a/writer.c

+++ b/writer.c

@@ -71,39 +71,6 @@

 	return b;

 }

-Wbuf *

-getwrite(void)

-{

-	Wbuf *b;

-

-	qlock(&drts.lck);

-	if(drts.n == 0){

-		if(stopwrites){

-			qunlock(&drts.lck);

-			return nil;

-		}

-		rsleep(&drts.isempty);

-		if(drts.n == 0 && stopwrites){

-			qunlock(&drts.lck);

-			return nil;

-		}

-	}

-	/* using canwlock() here as getbuf() could

-		have wlock()'ed the Iobuf too */

-	if(drts.head != nil){

-		b = pluck(drts.head);

-		if(drts.n == npendingwrites-1)

-			rwakeup(&drts.isfull);

-		if(chatty9p > 4 && b!=nil){

-			dprint("getwrite done b->blkno %llud\n", b->blkno);

-		stats();

-		}

-	}else

-		b = nil;

-	qunlock(&drts.lck);

-	return b;

-}

-

 /* the Iobuf should be wlock()'ed at entry */

 void

 putwrite(Iobuf *b)

@@ -154,33 +121,103 @@

 	incref(dirties) only happens with a wlock() in putwrite().

  */

 void

-dowrite(Wbuf *p)

+dowrite(void)

 {

-	u64 n;

+	Wbuf *b, *blks[128];

+	u64 prevblkno, startblkno, n, wn, i;

+	u8 full, *jumbo;

-	if(chatty9p > 4){

-		dprint("dowrite p->blkno %llud\n", p->blkno);

-		stats();

+	full = 0;

+	qlock(&drts.lck);

+	if(drts.n == 0){

+		if(stopwrites){

+			qunlock(&drts.lck);

+			return;

+		}

+		rsleep(&drts.isempty);

+		if(drts.n == 0 && stopwrites){

+			qunlock(&drts.lck);

+			return;

+		}

 	}

-	if(chatty9p > 4)

-		dprint("dowrite p->blkno %llud locked\n", p->blkno);

-	if((n = devwrite(p->blkno, p->payload)) != Rawblocksize){

-		dprint("%s\n", errstring[Esystem]);

-		panic("error writing block %llud: %llud bytes: %r\n",

-				p->blkno, n);

+	/* using canwlock() here as getbuf() could

+		have wlock()'ed the Iobuf too */

+	if(drts.head != nil){

+		if(drts.n == npendingwrites-1)

+			full = 1;

+		if(drts.n > 1){

+			/* trying to write consecutive blocks with a write() call */

+			n = 1;

+			prevblkno = startblkno = drts.head->blkno;

+			for(b = drts.head->next;

+					b != nil && b->blkno == prevblkno+1 && n < 128;

+					b = b->next){

+				prevblkno=b->blkno;

+				n++;

+			}

+			if(n > 1){

+				if(chatty9p > 4){

+					if(b != nil)

+					dprint("getwrite jumbo drts.n %llud > 1 n %llud start %llud next %llud\n",

+							drts.n, n, startblkno, b->blkno);

+					else

+					dprint("getwrite jumbo drts.n %llud > 1 n %llud start %llud\n",

+							drts.n, n, startblkno);

+				}

+				jumbo = emalloc9p(n*Rawblocksize);

+				for(i = 0; i < n; i++){

+					b = pluck(drts.head);

+					memcpy(jumbo+(i*Rawblocksize), b->payload, Rawblocksize);

+					blks[i] = b;

+					if(chatty9p > 4 && b!=nil)

+						dprint("getwrite done b->blkno %llud\n", b->blkno);

+				}

+				if((wn = devwrites(startblkno, jumbo, n)) != n*Rawblocksize){

+					dprint("%s\n", errstring[Esystem]);

+					panic("error writing block %llud: %llud bytes, written %llud: %r\n",

+							b->blkno, n, wn);

+				}

+				for(i = 0; i < n; i++){

+					b = blks[i];

+					blks[i] = 0;

+					if(chatty9p > 4)

+						dprint("dowrite %llud wunlock()'ed\n", b->blkno);

+					decref(&b->iobuf->dirties);

+					freememunit(b->payload);

+					free(b);

+				}

+				free(jumbo);

+				qunlock(&drts.lck);

+				return;

+			}

+			goto single;

+		}else{

+single:

+			b = pluck(drts.head);

+			if(chatty9p > 4 && b!=nil)

+				dprint("getwrite done b->blkno %llud\n", b->blkno);

+			if((n = devwrite(b->blkno, b->payload)) != Rawblocksize){

+				dprint("%s\n", errstring[Esystem]);

+				panic("error writing block %llud: %llud bytes: %r\n",

+						b->blkno, n);

+			}

+			if(chatty9p > 4)

+				dprint("dowrite %llud wunlock()'ed\n", b->blkno);

+			decref(&b->iobuf->dirties);

+			freememunit(b->payload);

+			free(b);

+		}

+		if(full)

+			rwakeup(&drts.isfull);

+		if(chatty9p > 4 && b!=nil)

+			stats();

 	}

-	n = p->blkno;

-	if(chatty9p > 4)

-	dprint("dowrite %llud wunlock()'ed\n", n);

-	decref(&p->iobuf->dirties);

-	freememunit(p->payload);

-	free(p);

+	qunlock(&drts.lck);

 }

 void

 initwriter(void)

 {

-	Wbuf *b;

 	char name[Namelen];

 	// set the locks used by the Rendezes

@@ -201,9 +238,7 @@

 	snprint(name, Namelen, "%s writer", service);

 	procsetname(name);

 	while(stopwrites == 0 || drts.n > 0){

-		b=getwrite();

-		if(b != nil)

-			dowrite(b);

+		dowrite();

 	}

 	if(chatty9p > 4)

 	dprint("%s process exited\n", name);