[U-Boot] [PATCH] JFFS2: accelerate scanning.

[Leo Liu]

This patch make the JFFS2 scanning faster in U-Boot.
1). if we find 1KB 0xFF data from the beginning of the erase block,skip it.
2). if the 1KB data is 0xFF after the cleanmarker, ship this erase block.

For the 16MB nor flash, the scanning time is changed from about 9s to 1s.

Signed-off-by: Leo Liu <liucai.lfn at gmail.com>
---
 fs/jffs2/jffs2_1pass.c      |   31 +++++++++++++++++++++----------
 fs/jffs2/jffs2_nand_1pass.c |    2 +-
 2 files changed, 22 insertions(+), 11 deletions(-)

diff --git a/fs/jffs2/jffs2_1pass.c b/fs/jffs2/jffs2_1pass.c
index dfb1745..f38f755 100644
--- a/fs/jffs2/jffs2_1pass.c
+++ b/fs/jffs2/jffs2_1pass.c
@@ -1441,7 +1441,7 @@ dump_dirents(struct b_lists *pL)
 }
 #endif
 
-#define DEFAULT_EMPTY_SCAN_SIZE	4096
+#define DEFAULT_EMPTY_SCAN_SIZE	1024
 
 static inline uint32_t EMPTY_SCAN_SIZE(uint32_t sector_size)
 {
@@ -1461,7 +1461,7 @@ jffs2_1pass_build_lists(struct part_info * part)
 	u32 counter4 = 0;
 	u32 counterF = 0;
 	u32 counterN = 0;
-	u32 buf_size = DEFAULT_EMPTY_SCAN_SIZE;
+	u32 buf_size = 128*1024;;
 	char *buf;
 
 	/* turn off the lcd.  Refreshing the lcd adds 50% overhead to the */
@@ -1559,14 +1559,17 @@ jffs2_1pass_build_lists(struct part_info * part)
 		/* We temporarily use 'ofs' as a pointer into the buffer/jeb */
 		ofs = 0;
 
-		/* Scan only 4KiB of 0xFF before declaring it's empty */
+		/* Scan only 1KiB of 0xFF before declaring it's empty */
 		while (ofs < EMPTY_SCAN_SIZE(part->sector_size) &&
 				*(uint32_t *)(&buf[ofs]) == 0xFFFFFFFF)
 			ofs += 4;
 
-		if (ofs == EMPTY_SCAN_SIZE(part->sector_size))
+		if (ofs == EMPTY_SCAN_SIZE(part->sector_size)) {
+			printf("Block at 0x%08x is empty (erased)\n", sector_ofs);
 			continue;
+		}
 
+		/* Now ofs is a complete physical flash offset as it always was... */
 		ofs += sector_ofs;
 		prevofs = ofs - 1;
 
@@ -1594,16 +1597,14 @@ jffs2_1pass_build_lists(struct part_info * part)
 
 			if (*(uint32_t *)(&buf[ofs-buf_ofs]) == 0xffffffff) {
 				uint32_t inbuf_ofs;
-				uint32_t empty_start, scan_end;
+				uint32_t empty_start;
 
 				empty_start = ofs;
 				ofs += 4;
-				scan_end = min_t(uint32_t, EMPTY_SCAN_SIZE(
-							part->sector_size)/8,
-							buf_len);
+				
 			more_empty:
 				inbuf_ofs = ofs - buf_ofs;
-				while (inbuf_ofs < scan_end) {
+				while (inbuf_ofs < buf_len) {
 					if (*(uint32_t *)(&buf[inbuf_ofs]) !=
 							0xffffffff)
 						goto scan_more;
@@ -1613,6 +1614,12 @@ jffs2_1pass_build_lists(struct part_info * part)
 				}
 				/* Ran off end. */
 
+				/* If we're only checking the beginning of a block with a cleanmarker,
+				   bail now */
+				if((buf_ofs == sector_ofs) && 
+					(node ==(struct jffs2_unknown_node *)&buf[ofs-buf_ofs])) 
+					break;
+	
 				/* See how much more there is to read in this
 				 * eraseblock...
 				 */
@@ -1627,12 +1634,12 @@ jffs2_1pass_build_lists(struct part_info * part)
 					 */
 					break;
 				}
-				scan_end = buf_len;
 				get_fl_mem((u32)part->offset + ofs, buf_len,
 					   buf);
 				buf_ofs = ofs;
 				goto more_empty;
 			}
+			
 			if (node->magic != JFFS2_MAGIC_BITMASK ||
 					!hdr_crc(node)) {
 				ofs += 4;
@@ -1650,6 +1657,8 @@ jffs2_1pass_build_lists(struct part_info * part)
 			case JFFS2_NODETYPE_INODE:
 				if (buf_ofs + buf_len < ofs + sizeof(struct
 							jffs2_raw_inode)) {
+					buf_len = min_t(uint32_t, buf_size, sector_ofs
+							+ part->sector_size - ofs);

 					get_fl_mem((u32)part->offset + ofs,
 						   buf_len, buf);
 					buf_ofs = ofs;
@@ -1671,6 +1680,8 @@ jffs2_1pass_build_lists(struct part_info * part)
 							((struct
 							 jffs2_raw_dirent *)
 							node)->nsize) {
+					buf_len = min_t(uint32_t, buf_size, sector_ofs
+							+ part->sector_size - ofs);

 					get_fl_mem((u32)part->offset + ofs,
 						   buf_len, buf);
 					buf_ofs = ofs;
diff --git a/fs/jffs2/jffs2_nand_1pass.c b/fs/jffs2/jffs2_nand_1pass.c
index e3bc536..16bb2e9 100644
--- a/fs/jffs2/jffs2_nand_1pass.c
+++ b/fs/jffs2/jffs2_nand_1pass.c
@@ -833,7 +833,7 @@ jffs2_1pass_build_lists(struct part_info * part)
 			return 0;
 
 		ofs = 0;
-		/* Scan only 4KiB of 0xFF before declaring it's empty */
+		/* Scan only 1KiB of 0xFF before declaring it's empty */
 		while (ofs < EMPTY_SCAN_SIZE && *(uint32_t *)(&buf[ofs]) == 0xFFFFFFFF)
 			ofs += 4;
 		if (ofs == EMPTY_SCAN_SIZE)
-- 
1.7.3.1.msysgit.0