in nftlcore.c [231:468]
static u16 NFTL_foldchain (struct NFTLrecord *nftl, unsigned thisVUC, unsigned pendingblock )
{
struct mtd_info *mtd = nftl->mbd.mtd;
u16 BlockMap[MAX_SECTORS_PER_UNIT];
unsigned char BlockLastState[MAX_SECTORS_PER_UNIT];
unsigned char BlockFreeFound[MAX_SECTORS_PER_UNIT];
unsigned int thisEUN;
int block;
int silly;
unsigned int targetEUN;
struct nftl_oob oob;
int inplace = 1;
size_t retlen;
memset(BlockMap, 0xff, sizeof(BlockMap));
memset(BlockFreeFound, 0, sizeof(BlockFreeFound));
thisEUN = nftl->EUNtable[thisVUC];
if (thisEUN == BLOCK_NIL) {
printk(KERN_WARNING "Trying to fold non-existent "
"Virtual Unit Chain %d!\n", thisVUC);
return BLOCK_NIL;
}
/* Scan to find the Erase Unit which holds the actual data for each
512-byte block within the Chain.
*/
silly = MAX_LOOPS;
targetEUN = BLOCK_NIL;
while (thisEUN <= nftl->lastEUN ) {
unsigned int status, foldmark;
targetEUN = thisEUN;
for (block = 0; block < nftl->EraseSize / 512; block ++) {
nftl_read_oob(mtd, (thisEUN * nftl->EraseSize) +
(block * 512), 16 , &retlen,
(char *)&oob);
if (block == 2) {
foldmark = oob.u.c.FoldMark | oob.u.c.FoldMark1;
if (foldmark == FOLD_MARK_IN_PROGRESS) {
pr_debug("Write Inhibited on EUN %d\n", thisEUN);
inplace = 0;
} else {
/* There's no other reason not to do inplace,
except ones that come later. So we don't need
to preserve inplace */
inplace = 1;
}
}
status = oob.b.Status | oob.b.Status1;
BlockLastState[block] = status;
switch(status) {
case SECTOR_FREE:
BlockFreeFound[block] = 1;
break;
case SECTOR_USED:
if (!BlockFreeFound[block])
BlockMap[block] = thisEUN;
else
printk(KERN_WARNING
"SECTOR_USED found after SECTOR_FREE "
"in Virtual Unit Chain %d for block %d\n",
thisVUC, block);
break;
case SECTOR_DELETED:
if (!BlockFreeFound[block])
BlockMap[block] = BLOCK_NIL;
else
printk(KERN_WARNING
"SECTOR_DELETED found after SECTOR_FREE "
"in Virtual Unit Chain %d for block %d\n",
thisVUC, block);
break;
case SECTOR_IGNORE:
break;
default:
printk("Unknown status for block %d in EUN %d: %x\n",
block, thisEUN, status);
}
}
if (!silly--) {
printk(KERN_WARNING "Infinite loop in Virtual Unit Chain 0x%x\n",
thisVUC);
return BLOCK_NIL;
}
thisEUN = nftl->ReplUnitTable[thisEUN];
}
if (inplace) {
/* We're being asked to be a fold-in-place. Check
that all blocks which actually have data associated
with them (i.e. BlockMap[block] != BLOCK_NIL) are
either already present or SECTOR_FREE in the target
block. If not, we're going to have to fold out-of-place
anyway.
*/
for (block = 0; block < nftl->EraseSize / 512 ; block++) {
if (BlockLastState[block] != SECTOR_FREE &&
BlockMap[block] != BLOCK_NIL &&
BlockMap[block] != targetEUN) {
pr_debug("Setting inplace to 0. VUC %d, "
"block %d was %x lastEUN, "
"and is in EUN %d (%s) %d\n",
thisVUC, block, BlockLastState[block],
BlockMap[block],
BlockMap[block]== targetEUN ? "==" : "!=",
targetEUN);
inplace = 0;
break;
}
}
if (pendingblock >= (thisVUC * (nftl->EraseSize / 512)) &&
pendingblock < ((thisVUC + 1)* (nftl->EraseSize / 512)) &&
BlockLastState[pendingblock - (thisVUC * (nftl->EraseSize / 512))] !=
SECTOR_FREE) {
pr_debug("Pending write not free in EUN %d. "
"Folding out of place.\n", targetEUN);
inplace = 0;
}
}
if (!inplace) {
pr_debug("Cannot fold Virtual Unit Chain %d in place. "
"Trying out-of-place\n", thisVUC);
/* We need to find a targetEUN to fold into. */
targetEUN = NFTL_findfreeblock(nftl, 1);
if (targetEUN == BLOCK_NIL) {
/* Ouch. Now we're screwed. We need to do a
fold-in-place of another chain to make room
for this one. We need a better way of selecting
which chain to fold, because makefreeblock will
only ask us to fold the same one again.
*/
printk(KERN_WARNING
"NFTL_findfreeblock(desperate) returns 0xffff.\n");
return BLOCK_NIL;
}
} else {
/* We put a fold mark in the chain we are folding only if we
fold in place to help the mount check code. If we do not fold in
place, it is possible to find the valid chain by selecting the
longer one */
oob.u.c.FoldMark = oob.u.c.FoldMark1 = cpu_to_le16(FOLD_MARK_IN_PROGRESS);
oob.u.c.unused = 0xffffffff;
nftl_write_oob(mtd, (nftl->EraseSize * targetEUN) + 2 * 512 + 8,
8, &retlen, (char *)&oob.u);
}
/* OK. We now know the location of every block in the Virtual Unit Chain,
and the Erase Unit into which we are supposed to be copying.
Go for it.
*/
pr_debug("Folding chain %d into unit %d\n", thisVUC, targetEUN);
for (block = 0; block < nftl->EraseSize / 512 ; block++) {
unsigned char movebuf[512];
int ret;
/* If it's in the target EUN already, or if it's pending write, do nothing */
if (BlockMap[block] == targetEUN ||
(pendingblock == (thisVUC * (nftl->EraseSize / 512) + block))) {
continue;
}
/* copy only in non free block (free blocks can only
happen in case of media errors or deleted blocks) */
if (BlockMap[block] == BLOCK_NIL)
continue;
ret = mtd_read(mtd,
(nftl->EraseSize * BlockMap[block]) + (block * 512),
512,
&retlen,
movebuf);
if (ret < 0 && !mtd_is_bitflip(ret)) {
ret = mtd_read(mtd,
(nftl->EraseSize * BlockMap[block]) + (block * 512),
512,
&retlen,
movebuf);
if (ret != -EIO)
printk("Error went away on retry.\n");
}
memset(&oob, 0xff, sizeof(struct nftl_oob));
oob.b.Status = oob.b.Status1 = SECTOR_USED;
nftl_write(nftl->mbd.mtd, (nftl->EraseSize * targetEUN) +
(block * 512), 512, &retlen, movebuf, (char *)&oob);
}
/* add the header so that it is now a valid chain */
oob.u.a.VirtUnitNum = oob.u.a.SpareVirtUnitNum = cpu_to_le16(thisVUC);
oob.u.a.ReplUnitNum = oob.u.a.SpareReplUnitNum = BLOCK_NIL;
nftl_write_oob(mtd, (nftl->EraseSize * targetEUN) + 8,
8, &retlen, (char *)&oob.u);
/* OK. We've moved the whole lot into the new block. Now we have to free the original blocks. */
/* At this point, we have two different chains for this Virtual Unit, and no way to tell
them apart. If we crash now, we get confused. However, both contain the same data, so we
shouldn't actually lose data in this case. It's just that when we load up on a medium which
has duplicate chains, we need to free one of the chains because it's not necessary any more.
*/
thisEUN = nftl->EUNtable[thisVUC];
pr_debug("Want to erase\n");
/* For each block in the old chain (except the targetEUN of course),
free it and make it available for future use */
while (thisEUN <= nftl->lastEUN && thisEUN != targetEUN) {
unsigned int EUNtmp;
EUNtmp = nftl->ReplUnitTable[thisEUN];
if (NFTL_formatblock(nftl, thisEUN) < 0) {
/* could not erase : mark block as reserved
*/
nftl->ReplUnitTable[thisEUN] = BLOCK_RESERVED;
} else {
/* correctly erased : mark it as free */
nftl->ReplUnitTable[thisEUN] = BLOCK_FREE;
nftl->numfreeEUNs++;
}
thisEUN = EUNtmp;
}
/* Make this the new start of chain for thisVUC */
nftl->ReplUnitTable[targetEUN] = BLOCK_NIL;
nftl->EUNtable[thisVUC] = targetEUN;
return targetEUN;
}