JFFS2-on-DataFlash : 1 - Core changes

Andrew Victor andrew at sanpeople.com
Tue Feb 1 03:44:15 EST 2005


hi,

Based on the previous comments, the patch has been split up.

The changes included in this patch are:

DataFlash page-sizes are not a power of two (they're multiples of 528
bytes).  There are a few places in JFFS2 code where sector_size is used
as a bitmask.  A new macro (SECTOR_ADDR) was defined to calculate these
sector addresses. For non-DataFlash devices, the original (faster)
bitmask operation is still used.

In scan.c, the EMPTY_SCAN_SIZE was a constant of 1024. 
Since this could be larger than the sector size of the DataFlash, this
is now basically set to MIN(sector_size, 1024).

Addition of a jffs2_is_writebuffered() macro.

Regards,
  Andrew Victor


diff -urN -x CVS mtd.orig/fs/jffs2/erase.c mtd.core/fs/jffs2/erase.c
--- mtd.orig/fs/jffs2/erase.c	Wed Jan 26 16:07:57 2005
+++ mtd.core/fs/jffs2/erase.c	Tue Feb  1 10:06:13 2005
@@ -233,7 +233,7 @@
 			continue;
 		} 
 
-		if (((*prev)->flash_offset & ~(c->sector_size -1)) == jeb->offset) {
+		if (SECTOR_ADDR((*prev)->flash_offset) == jeb->offset) {
 			/* It's in the block we're erasing */
 			struct jffs2_raw_node_ref *this;
 
diff -urN -x CVS mtd.orig/fs/jffs2/gc.c mtd.core/fs/jffs2/gc.c
--- mtd.orig/fs/jffs2/gc.c	Wed Jan 26 16:07:57 2005
+++ mtd.core/fs/jffs2/gc.c	Tue Feb  1 10:06:13 2005
@@ -816,8 +816,7 @@
 
 			/* Doesn't matter if there's one in the same erase block. We're going to 
 			   delete it too at the same time. */
-			if ((raw->flash_offset & ~(c->sector_size-1)) ==
-			    (fd->raw->flash_offset & ~(c->sector_size-1)))
+			if (SECTOR_ADDR(raw->flash_offset) == SECTOR_ADDR(fd->raw->flash_offset))
 				continue;
 
 			D1(printk(KERN_DEBUG "Check potential deletion dirent at %08x\n", ref_offset(raw)));
diff -urN -x CVS mtd.orig/fs/jffs2/os-linux.h mtd.core/fs/jffs2/os-linux.h
--- mtd.orig/fs/jffs2/os-linux.h	Wed Jan 26 16:07:58 2005
+++ mtd.core/fs/jffs2/os-linux.h	Tue Feb  1 10:06:13 2005
@@ -97,7 +97,10 @@
 #endif
 }
 
+#define SECTOR_ADDR(x) ( ((unsigned long)(x) & ~(c->sector_size-1)) )
+
 #define jffs2_is_readonly(c) (OFNI_BS_2SFFJ(c)->s_flags & MS_RDONLY)
+#define jffs2_is_writebuffered(c) (c->wbuf != NULL)
 
 #if (!defined CONFIG_JFFS2_FS_NAND && !defined CONFIG_JFFS2_FS_NOR_ECC)
 #define jffs2_can_mark_obsolete(c) (1)
diff -urN -x CVS mtd.orig/fs/jffs2/scan.c mtd.core/fs/jffs2/scan.c
--- mtd.orig/fs/jffs2/scan.c	Wed Jan 26 16:07:58 2005
+++ mtd.core/fs/jffs2/scan.c	Tue Feb  1 10:07:55 2005
@@ -19,7 +19,7 @@
 #include <linux/compiler.h>
 #include "nodelist.h"
 
-#define EMPTY_SCAN_SIZE 1024
+#define DEFAULT_EMPTY_SCAN_SIZE 1024
 
 #define DIRTY_SPACE(x) do { typeof(x) _x = (x); \
 		c->free_size -= _x; c->dirty_size += _x; \
@@ -75,6 +75,14 @@
 	return min;
 
 }
+
+static inline uint32_t EMPTY_SCAN_SIZE(uint32_t sector_size) {
+	if (sector_size < DEFAULT_EMPTY_SCAN_SIZE)
+		return sector_size;
+	else
+		return DEFAULT_EMPTY_SCAN_SIZE;
+}
+
 int jffs2_scan_medium(struct jffs2_sb_info *c)
 {
 	int i, ret;
@@ -316,7 +324,7 @@
 	if (!buf_size) {
 		buf_len = c->sector_size;
 	} else {
-		buf_len = EMPTY_SCAN_SIZE;
+		buf_len = EMPTY_SCAN_SIZE(c->sector_size);
 		err = jffs2_fill_scan_buf(c, buf, buf_ofs, buf_len);
 		if (err)
 			return err;
@@ -326,10 +334,10 @@
 	ofs = 0;
 
 	/* Scan only 4KiB of 0xFF before declaring it's empty */
-	while(ofs < EMPTY_SCAN_SIZE && *(uint32_t *)(&buf[ofs]) == 0xFFFFFFFF)
+	while(ofs < EMPTY_SCAN_SIZE(c->sector_size) && *(uint32_t *)(&buf[ofs]) == 0xFFFFFFFF)
 		ofs += 4;
 
-	if (ofs == EMPTY_SCAN_SIZE) {
+	if (ofs == EMPTY_SCAN_SIZE(c->sector_size)) {
 #ifdef CONFIG_JFFS2_FS_NAND
 		if (jffs2_cleanmarker_oob(c)) {
 			/* scan oob, take care of cleanmarker */
@@ -423,7 +431,7 @@
 			   bail now */
 			if (buf_ofs == jeb->offset && jeb->used_size == PAD(c->cleanmarker_size) && 
 			    c->cleanmarker_size && !jeb->dirty_size && !jeb->first_node->next_in_ino) {
-				D1(printk(KERN_DEBUG "%d bytes at start of block seems clean... assuming all clean\n", EMPTY_SCAN_SIZE));
+				D1(printk(KERN_DEBUG "%d bytes at start of block seems clean... assuming all clean\n", EMPTY_SCAN_SIZE(c->sector_size)));
 				return BLK_STATE_CLEANMARKER;
 			}
 
diff -urN -x CVS mtd.orig/fs/jffs2/wbuf.c mtd.core/fs/jffs2/wbuf.c
--- mtd.orig/fs/jffs2/wbuf.c	Wed Jan 26 16:07:58 2005
+++ mtd.core/fs/jffs2/wbuf.c	Tue Feb  1 10:06:13 2005
@@ -415,9 +415,9 @@
 	int ret;
 	size_t retlen;
 
-	/* Nothing to do if not NAND flash. In particular, we shouldn't
+	/* Nothing to do if not write-buffering the flash. In particular, we shouldn't
 	   del_timer() the timer we never initialised. */
-	if (jffs2_can_mark_obsolete(c))
+	if (!jffs2_is_writebuffered(c))
 		return 0;
 
 	if (!down_trylock(&c->alloc_sem)) {
@@ -426,7 +426,7 @@
 		BUG();
 	}
 
-	if(!c->wbuf || !c->wbuf_len)
+	if (!c->wbuf_len)	/* already checked c->wbuf above */
 		return 0;
 
 	/* claim remaining space on the page
@@ -614,7 +614,7 @@
 	uint32_t outvec_to = to;
 
 	/* If not NAND flash, don't bother */
-	if (!c->wbuf)
+	if (!jffs2_is_writebuffered(c))
 		return jffs2_flash_direct_writev(c, invecs, count, to, retlen);
 	
 	down_write(&c->wbuf_sem);
@@ -643,7 +643,7 @@
 	   erase block. Anything else, and you die.
 	   New block starts at xxx000c (0-b = block header)
 	*/
-	if ( (to & ~(c->sector_size-1)) != (c->wbuf_ofs & ~(c->sector_size-1)) ) {
+	if (SECTOR_ADDR(to) != SECTOR_ADDR(c->wbuf_ofs)) {
 		/* It's a write to a new block */
 		if (c->wbuf_len) {
 			D1(printk(KERN_DEBUG "jffs2_flash_writev() to 0x%lx causes flush of wbuf at 0x%08x\n", (unsigned long)to, c->wbuf_ofs));
@@ -841,7 +841,7 @@
 {
 	struct kvec vecs[1];
 
-	if (jffs2_can_mark_obsolete(c))
+	if (!jffs2_is_writebuffered(c))
 		return c->mtd->write(c->mtd, ofs, len, retlen, buf);
 
 	vecs[0].iov_base = (unsigned char *) buf;
@@ -857,39 +857,39 @@
 	loff_t	orbf = 0, owbf = 0, lwbf = 0;
 	int	ret;
 
+	if (!jffs2_is_writebuffered(c))
+		return c->mtd->read(c->mtd, ofs, len, retlen, buf);
+
 	/* Read flash */
-	if (!jffs2_can_mark_obsolete(c)) {
-		down_read(&c->wbuf_sem);
+	down_read(&c->wbuf_sem);
 
-		if (jffs2_cleanmarker_oob(c))
-			ret = c->mtd->read_ecc(c->mtd, ofs, len, retlen, buf, NULL, c->oobinfo);
-		else
-			ret = c->mtd->read(c->mtd, ofs, len, retlen, buf);
+	if (jffs2_cleanmarker_oob(c))
+		ret = c->mtd->read_ecc(c->mtd, ofs, len, retlen, buf, NULL, c->oobinfo);
+	else
+		ret = c->mtd->read(c->mtd, ofs, len, retlen, buf);
 
-		if ( (ret == -EBADMSG) && (*retlen == len) ) {
-			printk(KERN_WARNING "mtd->read(0x%zx bytes from 0x%llx) returned ECC error\n",
-			       len, ofs);
-			/* 
-			 * We have the raw data without ECC correction in the buffer, maybe 
-			 * we are lucky and all data or parts are correct. We check the node.
-			 * If data are corrupted node check will sort it out.
-			 * We keep this block, it will fail on write or erase and the we
-			 * mark it bad. Or should we do that now? But we should give him a chance.
-			 * Maybe we had a system crash or power loss before the ecc write or  
-			 * a erase was completed.
-			 * So we return success. :)
-			 */
-		 	ret = 0;
-		 }	
-	} else
-		return c->mtd->read(c->mtd, ofs, len, retlen, buf);
+	if ( (ret == -EBADMSG) && (*retlen == len) ) {
+		printk(KERN_WARNING "mtd->read(0x%zx bytes from 0x%llx) returned ECC error\n",
+		       len, ofs);
+		/* 
+		 * We have the raw data without ECC correction in the buffer, maybe 
+		 * we are lucky and all data or parts are correct. We check the node.
+		 * If data are corrupted node check will sort it out.
+		 * We keep this block, it will fail on write or erase and the we
+		 * mark it bad. Or should we do that now? But we should give him a chance.
+		 * Maybe we had a system crash or power loss before the ecc write or  
+		 * a erase was completed.
+		 * So we return success. :)
+		 */
+	 	ret = 0;
+	}	
 
 	/* if no writebuffer available or write buffer empty, return */
 	if (!c->wbuf_pagesize || !c->wbuf_len)
 		goto exit;
 
 	/* if we read in a different block, return */
-	if ( (ofs & ~(c->sector_size-1)) != (c->wbuf_ofs & ~(c->sector_size-1)) ) 
+	if (SECTOR_ADDR(ofs) != SECTOR_ADDR(c->wbuf_ofs))
 		goto exit;
 
 	if (ofs >= c->wbuf_ofs) {







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