/*===========================================================================*
* invalidate *
*===========================================================================*/
PUBLIC void invalidate(
dev_t device /* device whose blocks are to be purged */
)
{
/* Remove all the blocks belonging to some device from the cache. */
register struct buf *bp;
for (bp = &buf[0]; bp < &buf[nr_bufs]; bp++)
if (bp->b_dev == device) bp->b_dev = NO_DEV;
vm_forgetblocks();
}
/*===========================================================================*
* buf_pool *
*===========================================================================*/
PUBLIC void buf_pool(int new_nr_bufs)
{
/* Initialize the buffer pool. */
register struct buf *bp;
assert(new_nr_bufs > 0);
if(nr_bufs > 0) {
assert(buf);
(void) fs_sync();
for (bp = &buf[0]; bp < &buf[nr_bufs]; bp++) {
if(bp->bp) {
assert(bp->b_bytes > 0);
free_contig(bp->bp, bp->b_bytes);
}
}
}
if(buf)
free(buf);
if(!(buf = calloc(sizeof(buf[0]), new_nr_bufs)))
panic("couldn't allocate buf list (%d)", new_nr_bufs);
if(buf_hash)
free(buf_hash);
if(!(buf_hash = calloc(sizeof(buf_hash[0]), new_nr_bufs)))
panic("couldn't allocate buf hash list (%d)", new_nr_bufs);
nr_bufs = new_nr_bufs;
bufs_in_use = 0;
front = &buf[0];
rear = &buf[nr_bufs - 1];
for (bp = &buf[0]; bp < &buf[nr_bufs]; bp++) {
bp->b_blocknr = NO_BLOCK;
bp->b_dev = NO_DEV;
bp->b_next = bp + 1;
bp->b_prev = bp - 1;
bp->bp = NULL;
bp->b_bytes = 0;
}
buf[0].b_prev = NULL;
buf[nr_bufs - 1].b_next = NULL;
for (bp = &buf[0]; bp < &buf[nr_bufs]; bp++) bp->b_hash = bp->b_next;
buf_hash[0] = front;
vm_forgetblocks();
}
/*===========================================================================*
* rw_scattered *
*===========================================================================*/
PUBLIC void rw_scattered(
dev_t dev, /* major-minor device number */
struct buf **bufq, /* pointer to array of buffers */
int bufqsize, /* number of buffers */
int rw_flag /* READING or WRITING */
)
{
/* Read or write scattered data from a device. */
register struct buf *bp;
int gap;
register int i;
register iovec_t *iop;
static iovec_t *iovec = NULL;
int j, r;
STATICINIT(iovec, NR_IOREQS);
/* (Shell) sort buffers on b_blocknr. */
gap = 1;
do
gap = 3 * gap + 1;
while (gap <= bufqsize);
while (gap != 1) {
gap /= 3;
for (j = gap; j < bufqsize; j++) {
for (i = j - gap;
i >= 0 && bufq[i]->b_blocknr > bufq[i + gap]->b_blocknr;
i -= gap) {
bp = bufq[i];
bufq[i] = bufq[i + gap];
bufq[i + gap] = bp;
}
}
}
/* Set up I/O vector and do I/O. The result of dev_io is OK if everything
* went fine, otherwise the error code for the first failed transfer.
*/
while (bufqsize > 0) {
for (j = 0, iop = iovec; j < NR_IOREQS && j < bufqsize; j++, iop++) {
bp = bufq[j];
if (bp->b_blocknr != (block_t) bufq[0]->b_blocknr + j) break;
iop->iov_addr = (vir_bytes) bp->b_data;
iop->iov_size = (vir_bytes) fs_block_size;
}
r = block_dev_io(rw_flag == WRITING ? MFS_DEV_SCATTER : MFS_DEV_GATHER,
dev, SELF_E, iovec,
mul64u(bufq[0]->b_blocknr, fs_block_size), j);
/* Harvest the results. Dev_io reports the first error it may have
* encountered, but we only care if it's the first block that failed.
*/
for (i = 0, iop = iovec; i < j; i++, iop++) {
bp = bufq[i];
if (iop->iov_size != 0) {
/* Transfer failed. An error? Do we care? */
if (r != OK && i == 0) {
printf(
"fs: I/O error on device %d/%d, block %lu\n",
major(dev), minor(dev), bp->b_blocknr);
bp->b_dev = NO_DEV; /* invalidate block */
vm_forgetblocks();
}
break;
}
if (rw_flag == READING) {
bp->b_dev = dev; /* validate block */
put_block(bp, PARTIAL_DATA_BLOCK);
} else {
bp->b_dirt = CLEAN;
}
}
bufq += i;
bufqsize -= i;
if (rw_flag == READING) {
/* Don't bother reading more than the device is willing to
* give at this time. Don't forget to release those extras.
*/
while (bufqsize > 0) {
put_block(*bufq++, PARTIAL_DATA_BLOCK);
bufqsize--;
}
}
if (rw_flag == WRITING && i == 0) {
/* We're not making progress, this means we might keep
* looping. Buffers remain dirty if un-written. Buffers are
* lost if invalidate()d or LRU-removed while dirty. This
* is better than keeping unwritable blocks around forever..
*/
break;
}
}
}
/*===========================================================================*
* rw_scattered *
*===========================================================================*/
void rw_scattered(
dev_t dev, /* major-minor device number */
struct buf **bufq, /* pointer to array of buffers */
int bufqsize, /* number of buffers */
int rw_flag /* READING or WRITING */
)
{
/* Read or write scattered data from a device. */
register struct buf *bp;
int gap;
register int i;
register iovec_t *iop;
static iovec_t *iovec = NULL;
u64_t pos;
int j, r;
STATICINIT(iovec, NR_IOREQS);
assert(bufq != NULL);
/* (Shell) sort buffers on b_blocknr. */
gap = 1;
do
gap = 3 * gap + 1;
while (gap <= bufqsize);
while (gap != 1) {
gap /= 3;
for (j = gap; j < bufqsize; j++) {
for (i = j - gap;
i >= 0 && bufq[i]->b_blocknr > bufq[i + gap]->b_blocknr;
i -= gap) {
bp = bufq[i];
bufq[i] = bufq[i + gap];
bufq[i + gap] = bp;
}
}
}
/* Set up I/O vector and do I/O. The result of dev_io is OK if everything
* went fine, otherwise the error code for the first failed transfer.
*/
while (bufqsize > 0) {
for (j = 0, iop = iovec; j < NR_IOREQS && j < bufqsize; j++, iop++) {
bp = bufq[j];
if (bp->b_blocknr != (block_t) bufq[0]->b_blocknr + j) break;
iop->iov_addr = (vir_bytes) bp->b_data;
iop->iov_size = (vir_bytes) fs_block_size;
}
pos = mul64u(bufq[0]->b_blocknr, fs_block_size);
if (rw_flag == READING)
r = bdev_gather(dev, pos, iovec, j, BDEV_NOFLAGS);
else
r = bdev_scatter(dev, pos, iovec, j, BDEV_NOFLAGS);
/* Harvest the results. The driver may have returned an error, or it
* may have done less than what we asked for.
*/
if (r < 0) {
printf("ext2: I/O error %d on device %d/%d, block %u\n",
r, major(dev), minor(dev), bufq[0]->b_blocknr);
}
for (i = 0; i < j; i++) {
bp = bufq[i];
if (r < (ssize_t) fs_block_size) {
/* Transfer failed. */
if (i == 0) {
bp->b_dev = NO_DEV; /* invalidate block */
vm_forgetblocks();
}
break;
}
if (rw_flag == READING) {
bp->b_dev = dev; /* validate block */
put_block(bp, PARTIAL_DATA_BLOCK);
} else {
bp->b_dirt = CLEAN;
}
r -= fs_block_size;
}
bufq += i;
bufqsize -= i;
if (rw_flag == READING) {
/* Don't bother reading more than the device is willing to
* give at this time. Don't forget to release those extras.
*/
while (bufqsize > 0) {
put_block(*bufq++, PARTIAL_DATA_BLOCK);
bufqsize--;
}
}
if (rw_flag == WRITING && i == 0) {
/* We're not making progress, this means we might keep
* looping. Buffers remain dirty if un-written. Buffers are
* lost if invalidate()d or LRU-removed while dirty. This
* is better than keeping unwritable blocks around forever..
*/
break;
}
}
}
