X-Git-Url: http://git.harvie.cz/?a=blobdiff_plain;f=c%2Fmdraid-gen%2Fmdraid.c;h=5f2720ef4d605e3f6372dd718b6e29a17c0b7adb;hb=HEAD;hp=8a600529fcf1d2941b2227689f45ff1c27908b97;hpb=30d358cd5a66ea85b06729df8fa13a068ac21d51;p=mirrors%2FPrograms.git

diff --git a/c/mdraid-gen/mdraid.c b/c/mdraid-gen/mdraid.c
index 8a60052..5f2720e 100644
--- a/c/mdraid-gen/mdraid.c
+++ b/c/mdraid-gen/mdraid.c
@@ -9,6 +9,10 @@ mdadm --examine test.img
 losetup /dev/loop1 test.img
 mdadm --assemble md /dev/loop1
 
+Some docs:
+https://raid.wiki.kernel.org/index.php/RAID_superblock_formats#Sub-versions_of_the_version-1_superblock
+https://docs.huihoo.com/doxygen/linux/kernel/3.7/md__p_8h_source.html
+
 */
 
 //#include <cstddef>
@@ -59,7 +63,9 @@ static unsigned int calc_sb_1_csum(struct mdp_superblock_1 * sb)
 }
 
 int main() {
-	size_t data_size = 10000; //512B sectors
+	//printf("Superblock\n");
+
+	size_t data_size = 8192; //512B sectors (should be divisible by 8 sectors to keep 4kB alignment)
 
 	srand(time(NULL)); //FIXME: Seed UUID properly
 
@@ -68,7 +74,7 @@ int main() {
 	/* constant array information - 128 bytes */
 	sb.magic = 0xa92b4efc;		/* MD_SB_MAGIC: 0xa92b4efc - little endian */
 	sb.major_version = 1;	/* 1 */
-	sb.feature_map = 0;	/* bit 0 set if 'bitmap_offset' is meaningful */
+	sb.feature_map = 0; //MD_FEATURE_BITMAP_OFFSET;	/* bit 0 set if 'bitmap_offset' is meaningful */ //FIXME: internal bitmap bit is not seen by mdadm????
 	sb.pad0 = 0;		/* always set to 0 when writing */
 
 	//TODO: set these
@@ -78,7 +84,7 @@ int main() {
 
 	sb.level=1;		/* -4 (multipath), -1 (linear), 0,1,4,5 */
 	//sb.layout=2;		/* only for raid5 and raid10 currently */
-	sb.size=data_size+128;		/* used size of component devices, in 512byte sectors */
+	sb.size=data_size;	/* used size of component devices, in 512byte sectors */
 
 	sb.chunksize=0;		/* in 512byte sectors - not used in raid 1 */
 	sb.raid_disks=1;
@@ -88,7 +94,7 @@ int main() {
 					 */
 
 	/* constant this-device information - 64 bytes */
-	sb.data_offset=128;	/* sector start of data, often 0 */
+	sb.data_offset=2048;	/* sector start of data, often 0 */
 	sb.data_size=data_size;	/* sectors in this device that can be used for data */
 	sb.super_offset=8;	/* sector start of this superblock */
 
@@ -99,11 +105,19 @@ int main() {
 		//#define	WriteMostly1	1	/* mask for writemostly flag in above */
 		//#define	FailFast1	2	/* Should avoid retries and fixups and just fail */
 
+		/* Bad block log.  If there are any bad blocks the feature flag is set.
+		* If offset and size are non-zero, that space is reserved and available
+		*/
+	sb.bblog_shift=9;    /* shift from sectors to block size */ //FIXME: not sure with this!
+	sb.bblog_size=8; /* number of sectors reserved for list */
+	sb.bblog_offset=16;   /* sector offset from superblock to bblog,
+			* signed - not unsigned */
+
 	/* array state information - 64 bytes */
 	sb.utime=0;		/* 40 bits second, 24 bits microseconds */
 	sb.events=0;		/* incremented when superblock updated */
 	sb.resync_offset=0;	/* data before this offset (from data_offset) known to be in sync */
-	sb.max_dev=1;	/* size of devs[] array to consider */
+	sb.max_dev=sb.raid_disks; /* size of devs[] array to consider */
 	//__u8	pad3[64-32];	/* set to 0 when writing */
 
 	/* device state information. Indexed by dev_number.
@@ -115,12 +129,16 @@ int main() {
 	//__le16	dev_roles[];	/* role in array, or 0xffff for a spare, or 0xfffe for faulty */
 
 
+	//Calculate checksum
 	sb.sb_csum=calc_sb_1_csum(&sb);
 
-	//printf("Superblock\n");
-	for(int i=0;i<(8*512);i++) putc(0, stdout);
+	//Empty space before metadata (sector 0 - 7)
+	for(int i=0;i<(sb.super_offset*512);i++) putc(0, stdout);
+
+	//Superblock and padding (sector 8 - 2048)
 	fwrite(&sb, sizeof(sb), 1, stdout);
-	for(int i=0;i<((120*512)-sizeof(sb));i++) putc(0, stdout);
+	for(int i=0;i<(((sb.data_offset-sb.super_offset)*512)-sizeof(sb));i++) putc(0, stdout);
 
+	//Data (N sectors)
 	for(int i=0;i<(data_size*512);i++) putc(0, stdout);
 }