[JFFS2] Core changes required to support JFFS2-on-Dataflash devices.

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.
Signed-off-by: Andrew Victor <andrew@sanpeople.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

fs/jffs2/erase.c

@@ -7,7 +7,7 @@
  *
  * For licensing information, see the file 'LICENCE' in this directory.
  *
- * $Id: erase.c,v 1.66 2004/11/16 20:36:11 dwmw2 Exp $
+ * $Id: erase.c,v 1.70 2005/02/09 09:09:01 pavlov Exp $
  *
  */
 
@@ -233,7 +233,7 @@ static inline void jffs2_remove_node_refs_from_ino_list(struct jffs2_sb_info *c,
 			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;
 

fs/jffs2/gc.c

@@ -7,7 +7,7 @@
  *
  * For licensing information, see the file 'LICENCE' in this directory.
  *
- * $Id: gc.c,v 1.144 2004/12/21 11:18:50 dwmw2 Exp $
+ * $Id: gc.c,v 1.145 2005/02/09 09:09:01 pavlov Exp $
  *
  */
 
@@ -816,8 +816,7 @@ static int jffs2_garbage_collect_deletion_dirent(struct jffs2_sb_info *c, struct
 
 			/* 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)));

fs/jffs2/os-linux.h

@@ -7,7 +7,7 @@
  *
  * For licensing information, see the file 'LICENCE' in this directory.
  *
- * $Id: os-linux.h,v 1.51 2004/11/16 20:36:11 dwmw2 Exp $
+ * $Id: os-linux.h,v 1.52 2005/02/09 09:09:01 pavlov Exp $
  *
  */
 
@@ -97,7 +97,10 @@ static inline void jffs2_init_inode_info(struct jffs2_inode_info *f)
 #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)

fs/jffs2/scan.c

@@ -7,7 +7,7 @@
  *
  * For licensing information, see the file 'LICENCE' in this directory.
  *
- * $Id: scan.c,v 1.115 2004/11/17 12:59:08 dedekind Exp $
+ * $Id: scan.c,v 1.116 2005/02/09 09:09:02 pavlov Exp $
  *
  */
 #include <linux/kernel.h>
@@ -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 @@ static inline int min_free(struct jffs2_sb_info *c)
 	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 @@ static int jffs2_scan_eraseblock (struct jffs2_sb_info *c, struct jffs2_eraseblo
 	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 @@ static int jffs2_scan_eraseblock (struct jffs2_sb_info *c, struct jffs2_eraseblo
 	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 @@ scan_more:
 			   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;
 			}
 

fs/jffs2/wbuf.c

@@ -9,7 +9,7 @@
  *
  * For licensing information, see the file 'LICENCE' in this directory.
  *
- * $Id: wbuf.c,v 1.86 2005/02/05 18:23:37 hammache Exp $
+ * $Id: wbuf.c,v 1.87 2005/02/09 09:09:02 pavlov Exp $
  *
  */
 
@@ -415,9 +415,9 @@ static int __jffs2_flush_wbuf(struct jffs2_sb_info *c, int pad)
 	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 @@ static int __jffs2_flush_wbuf(struct jffs2_sb_info *c, int pad)
 		BUG();
 	}
 
-	if(!c->wbuf || !c->wbuf_len)
+	if (!c->wbuf_len)	/* already checked c->wbuf above */
 		return 0;
 
 	/* claim remaining space on the page
@@ -620,7 +620,7 @@ int jffs2_flash_writev(struct jffs2_sb_info *c, const struct kvec *invecs, unsig
 	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);
@@ -649,7 +649,7 @@ int jffs2_flash_writev(struct jffs2_sb_info *c, const struct kvec *invecs, unsig
 	   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));
@@ -847,7 +847,7 @@ int jffs2_flash_write(struct jffs2_sb_info *c, loff_t ofs, size_t len, size_t *r
 {
 	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;
@@ -863,9 +863,10 @@ int jffs2_flash_read(struct jffs2_sb_info *c, loff_t ofs, size_t len, size_t *re
 	loff_t	orbf = 0, owbf = 0, lwbf = 0;
 	int	ret;
 
-	/* Read flash */
-	if (!jffs2_can_mark_obsolete(c)) {
+	if (!jffs2_is_writebuffered(c))
+		return c->mtd->read(c->mtd, ofs, len, retlen, buf);
 
+	/* Read flash */
 	if (jffs2_cleanmarker_oob(c))
 		ret = c->mtd->read_ecc(c->mtd, ofs, len, retlen, buf, NULL, c->oobinfo);
 	else
@@ -886,15 +887,13 @@ int jffs2_flash_read(struct jffs2_sb_info *c, loff_t ofs, size_t len, size_t *re
 		 */
 	 	ret = 0;
 	}	
-	} else
-		return c->mtd->read(c->mtd, ofs, len, retlen, buf);
 
 	/* if no writebuffer available or write buffer empty, return */
 	if (!c->wbuf_pagesize || !c->wbuf_len)
 		return ret;;
 
 	/* 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))
 		return ret;
 
 	/* Lock only if we have reason to believe wbuf contains relevant data,