On Fri, Oct 07, 2005 at 01:09:21PM +1000, Neil Brown wrote:
> However it is usually easier to read a whole patch - reading a patch
> that removes bits of a previous patch, and depends on other bits of
> it, requires holding too much in one's brain at once. If you could
> possibly send a complete patch against a recent release kernel, it
> would make review a lot easier.
Here's the latest version of the patch. What's been done since last time:
- There's no longer a set of “larger” stripes; instead, they're all shrunk
and then expanded, like you requested the last time.
- The expand stripes are preallocated in sync_request(), again like you
requested.
- Likewise, the raid5_conf struct is never reallocated; instead, I just make
sure it supports MAX_MD_DEVS devices in the first place. This wasted a
kilobyte or so per active device, but it removed a _lot_ of fiddly code,
so I believe it's a good thing.
- The patch in general is a lot slimmer (about half the size of the original
patch). Lots of special-case code has been thrown out and replaced by using
the generic functions instead (for, say, all the parity disk layout stuff).
I'm unsure how many regressions there are; there are still problems with
stuff hanging here and there, for one, and I'm unsure if I broke something
at the very end of the expand (raid5_finish_expand). I haven't seen the
problems with data corruption during heavy I/O yet, but OTOH it hasn't gotten
that much testing yet either. Much of the code is new or rewritten, so expect
regressions. :-)
There's no new functionality (in particular, still no crash recovery), but I
think it's a step in the right direction.
This patch is against 2.6.13, which was the latest kernel version I could get
to work with kdb. kdb helps a _lot_ in debugging the more obscure bugs, so
it's taken a significant amount of pain away :-)
> I find disassembly works quite well.
> You can even
> make drives/md/raid5.lst
> which gives you a listing to read.
The listings are basically useless. 90% of the code lines map to address 0x0,
and in the main functions (say, handle_stripe) there's hardly a code line
except some __set_bit etc. here and there. And yes, I compile with -O0 :-)
objdump --source gives me almost exactly the same thing.
/* Steinar */
--
Homepage: http://www.sesse.net/
--- /usr/src/old/linux-2.6.13/drivers/md/raid5.c 2005-08-29 01:41:01.000000000 +0200
+++ drivers/md/raid5.c 2005-10-14 21:50:06.000000000 +0200
@@ -68,16 +68,29 @@
#endif
static void print_raid5_conf (raid5_conf_t *conf);
+#if RAID5_DEBUG
+static void print_sh (struct stripe_head *sh);
+#endif
+static sector_t sync_request(mddev_t *mddev, sector_t sector_nr, int *skipped, int go_faster);
+static void raid5_finish_expand (raid5_conf_t *conf);
+static sector_t raid5_compute_sector(sector_t r_sector, unsigned int raid_disks,
+ unsigned int data_disks, unsigned int * dd_idx,
+ unsigned int * pd_idx, raid5_conf_t *conf);
static inline void __release_stripe(raid5_conf_t *conf, struct stripe_head *sh)
{
+ BUG_ON(atomic_read(&sh->count) == 0);
if (atomic_dec_and_test(&sh->count)) {
if (!list_empty(&sh->lru))
BUG();
if (atomic_read(&conf->active_stripes)==0)
BUG();
if (test_bit(STRIPE_HANDLE, &sh->state)) {
- if (test_bit(STRIPE_DELAYED, &sh->state))
+ if (test_bit(STRIPE_DELAY_EXPAND, &sh->state)) {
+ list_add_tail(&sh->lru, &conf->wait_for_expand_list);
+ printk("delaying stripe with sector %llu (expprog=%llu, active=%d)\n", sh->sector,
+ conf->expand_progress, atomic_read(&conf->active_stripes));
+ } else if (test_bit(STRIPE_DELAYED, &sh->state))
list_add_tail(&sh->lru, &conf->delayed_list);
else
list_add_tail(&sh->lru, &conf->handle_list);
@@ -133,7 +146,7 @@ static __inline__ void insert_hash(raid5
/* find an idle stripe, make sure it is unhashed, and return it. */
-static struct stripe_head *get_free_stripe(raid5_conf_t *conf)
+static struct stripe_head *get_free_stripe(raid5_conf_t *conf, int expand)
{
struct stripe_head *sh = NULL;
struct list_head *first;
@@ -146,6 +159,12 @@ static struct stripe_head *get_free_stri
list_del_init(first);
remove_hash(sh);
atomic_inc(&conf->active_stripes);
+
+ if (expand || !conf->expand_in_progress)
+ sh->disks = conf->raid_disks;
+ else
+ sh->disks = conf->previous_raid_disks;
+
out:
return sh;
}
@@ -184,7 +203,7 @@ static void raid5_build_block (struct st
static inline void init_stripe(struct stripe_head *sh, sector_t sector, int pd_idx)
{
raid5_conf_t *conf = sh->raid_conf;
- int disks = conf->raid_disks, i;
+ int i;
if (atomic_read(&sh->count) != 0)
BUG();
@@ -200,8 +219,14 @@ static inline void init_stripe(struct st
sh->sector = sector;
sh->pd_idx = pd_idx;
sh->state = 0;
+
+ if (conf->expand_in_progress && sector * (conf->raid_disks - 1) >= conf->expand_progress) {
+ sh->disks = conf->previous_raid_disks;
+ } else {
+ sh->disks = conf->raid_disks;
+ }
- for (i=disks; i--; ) {
+ for (i=sh->disks; i--; ) {
struct r5dev *dev = &sh->dev[i];
if (dev->toread || dev->towrite || dev->written ||
@@ -245,9 +270,26 @@ static struct stripe_head *get_active_st
do {
sh = __find_stripe(conf, sector);
+
+ // make sure this is of the right size; if not, remove it from the hash
+ // FIXME: is this needed now?
+ if (sh) {
+ int correct_disks = conf->raid_disks;
+ if (conf->expand_in_progress && sector * (conf->raid_disks - 1) >= conf->expand_progress) {
+ correct_disks = conf->previous_raid_disks;
+ }
+
+ if (sh->disks != correct_disks) {
+ BUG_ON(atomic_read(&sh->count) != 0);
+
+ remove_hash(sh);
+ sh = NULL;
+ }
+ }
+
if (!sh) {
if (!conf->inactive_blocked)
- sh = get_free_stripe(conf);
+ sh = get_free_stripe(conf, 1);
if (noblock && sh == NULL)
break;
if (!sh) {
@@ -267,8 +309,9 @@ static struct stripe_head *get_active_st
if (!list_empty(&sh->lru))
BUG();
} else {
- if (!test_bit(STRIPE_HANDLE, &sh->state))
+ if (!test_bit(STRIPE_HANDLE, &sh->state)) {
atomic_inc(&conf->active_stripes);
+ }
if (list_empty(&sh->lru))
BUG();
list_del_init(&sh->lru);
@@ -303,6 +346,7 @@ static int grow_stripes(raid5_conf_t *co
return 1;
memset(sh, 0, sizeof(*sh) + (devs-1)*sizeof(struct r5dev));
sh->raid_conf = conf;
+ sh->disks = conf->raid_disks;
spin_lock_init(&sh->lock);
if (grow_buffers(sh, conf->raid_disks)) {
@@ -325,7 +369,7 @@ static void shrink_stripes(raid5_conf_t
while (1) {
spin_lock_irq(&conf->device_lock);
- sh = get_free_stripe(conf);
+ sh = get_free_stripe(conf, 0);
spin_unlock_irq(&conf->device_lock);
if (!sh)
break;
@@ -344,7 +388,7 @@ static int raid5_end_read_request (struc
{
struct stripe_head *sh = bi->bi_private;
raid5_conf_t *conf = sh->raid_conf;
- int disks = conf->raid_disks, i;
+ int disks = sh->disks, i;
int uptodate = test_bit(BIO_UPTODATE, &bi->bi_flags);
if (bi->bi_size)
@@ -411,12 +455,61 @@ static int raid5_end_read_request (struc
return 0;
}
+
+static void raid5_finish_expand (raid5_conf_t *conf)
+{
+ int i;
+ struct disk_info *tmp;
+// shrink_stripes(conf);
+
+ conf->expand_in_progress = 0;
+
+ for (i = conf->previous_raid_disks; i < conf->raid_disks; i++) {
+ tmp = conf->disks + i;
+ if (tmp->rdev
+ && !tmp->rdev->faulty
+ && !tmp->rdev->in_sync) {
+ conf->mddev->degraded--;
+ conf->failed_disks--;
+ conf->working_disks++;
+ tmp->rdev->in_sync = 1;
+ }
+ }
+
+ // inform the md code that we have more space now
+ {
+ struct block_device *bdev;
+ sector_t sync_sector;
+ unsigned dummy1, dummy2;
+
+ conf->mddev->array_size = conf->mddev->size * (conf->mddev->raid_disks-1);
+ set_capacity(conf->mddev->gendisk, conf->mddev->array_size << 1);
+ conf->mddev->changed = 1;
+
+ sync_sector = raid5_compute_sector(conf->expand_progress, conf->raid_disks,
+ conf->raid_disks - 1, &dummy1, &dummy2, conf);
+
+ conf->mddev->recovery_cp = sync_sector << 1; // FIXME: hum, hum
+ set_bit(MD_RECOVERY_NEEDED, &conf->mddev->recovery);
+
+ bdev = bdget_disk(conf->mddev->gendisk, 0);
+ if (bdev) {
+ down(&bdev->bd_inode->i_sem);
+ i_size_write(bdev->bd_inode, conf->mddev->array_size << 10);
+ up(&bdev->bd_inode->i_sem);
+ bdput(bdev);
+ }
+ }
+
+ /* FIXME: free old stuff here! (what are we missing?) */
+}
+
static int raid5_end_write_request (struct bio *bi, unsigned int bytes_done,
int error)
{
struct stripe_head *sh = bi->bi_private;
raid5_conf_t *conf = sh->raid_conf;
- int disks = conf->raid_disks, i;
+ int disks = sh->disks, i;
unsigned long flags;
int uptodate = test_bit(BIO_UPTODATE, &bi->bi_flags);
@@ -570,7 +663,7 @@ static sector_t raid5_compute_sector(sec
static sector_t compute_blocknr(struct stripe_head *sh, int i)
{
raid5_conf_t *conf = sh->raid_conf;
- int raid_disks = conf->raid_disks, data_disks = raid_disks - 1;
+ int raid_disks = sh->disks, data_disks = raid_disks - 1;
sector_t new_sector = sh->sector, check;
int sectors_per_chunk = conf->chunk_size >> 9;
sector_t stripe;
@@ -605,7 +698,8 @@ static sector_t compute_blocknr(struct s
check = raid5_compute_sector (r_sector, raid_disks, data_disks, &dummy1, &dummy2, conf);
if (check != sh->sector || dummy1 != dd_idx || dummy2 != sh->pd_idx) {
- printk("compute_blocknr: map not correct\n");
+ printk("compute_blocknr: map not correct (%llu,%u,%u vs. %llu,%u,%u) disks=%u offset=%u virtual_dd=%u\n",
+ check, dummy1, dummy2, sh->sector, dd_idx, sh->pd_idx, sh->disks, chunk_offset, i);
return 0;
}
return r_sector;
@@ -671,8 +765,7 @@ static void copy_data(int frombio, struc
static void compute_block(struct stripe_head *sh, int dd_idx)
{
- raid5_conf_t *conf = sh->raid_conf;
- int i, count, disks = conf->raid_disks;
+ int i, count, disks = sh->disks;
void *ptr[MAX_XOR_BLOCKS], *p;
PRINTK("compute_block, stripe %llu, idx %d\n",
@@ -702,7 +795,7 @@ static void compute_block(struct stripe_
static void compute_parity(struct stripe_head *sh, int method)
{
raid5_conf_t *conf = sh->raid_conf;
- int i, pd_idx = sh->pd_idx, disks = conf->raid_disks, count;
+ int i, pd_idx = sh->pd_idx, disks = sh->disks, count;
void *ptr[MAX_XOR_BLOCKS];
struct bio *chosen;
@@ -876,11 +969,11 @@ static int add_stripe_bio(struct stripe_
* get BH_Lock set before the stripe lock is released.
*
*/
-
+
static void handle_stripe(struct stripe_head *sh)
{
raid5_conf_t *conf = sh->raid_conf;
- int disks = conf->raid_disks;
+ int disks = sh->disks;
struct bio *return_bi= NULL;
struct bio *bi;
int i;
@@ -897,6 +990,7 @@ static void handle_stripe(struct stripe_
spin_lock(&sh->lock);
clear_bit(STRIPE_HANDLE, &sh->state);
clear_bit(STRIPE_DELAYED, &sh->state);
+ clear_bit(STRIPE_DELAY_EXPAND, &sh->state);
syncing = test_bit(STRIPE_SYNCING, &sh->state);
/* Now to look around and see what can be done */
@@ -945,19 +1039,20 @@ static void handle_stripe(struct stripe_
}
if (dev->written) written++;
rdev = conf->disks[i].rdev; /* FIXME, should I be looking rdev */
- if (!rdev || !rdev->in_sync) {
+ if (!conf->expand_in_progress && (!rdev || !rdev->in_sync)) {
failed++;
failed_num = i;
} else
set_bit(R5_Insync, &dev->flags);
}
- PRINTK("locked=%d uptodate=%d to_read=%d"
- " to_write=%d failed=%d failed_num=%d\n",
- locked, uptodate, to_read, to_write, failed, failed_num);
/* check if the array has lost two devices and, if so, some requests might
* need to be failed
*/
if (failed > 1 && to_read+to_write+written) {
+ printk("Need to fail requests!\n");
+ printk("locked=%d uptodate=%d to_read=%d"
+ " to_write=%d failed=%d failed_num=%d disks=%d\n",
+ locked, uptodate, to_read, to_write, failed, failed_num, disks);
spin_lock_irq(&conf->device_lock);
for (i=disks; i--; ) {
/* fail all writes first */
@@ -1012,7 +1107,7 @@ static void handle_stripe(struct stripe_
}
spin_unlock_irq(&conf->device_lock);
}
- if (failed > 1 && syncing) {
+ if (failed > 1 && syncing && !conf->expand_in_progress) {
md_done_sync(conf->mddev, STRIPE_SECTORS,0);
clear_bit(STRIPE_SYNCING, &sh->state);
syncing = 0;
@@ -1085,7 +1180,7 @@ static void handle_stripe(struct stripe_
/* if I am just reading this block and we don't have
a failed drive, or any pending writes then sidestep the cache */
if (sh->bh_read[i] && !sh->bh_read[i]->b_reqnext &&
- ! syncing && !failed && !to_write) {
+ ! syncing && !failed && !to_write) {
sh->bh_cache[i]->b_page = sh->bh_read[i]->b_page;
sh->bh_cache[i]->b_data = sh->bh_read[i]->b_data;
}
@@ -1093,7 +1188,7 @@ static void handle_stripe(struct stripe_
locked++;
PRINTK("Reading block %d (sync=%d)\n",
i, syncing);
- if (syncing)
+ if (syncing && !conf->expand_in_progress)
md_sync_acct(conf->disks[i].rdev->bdev,
STRIPE_SECTORS);
}
@@ -1102,6 +1197,273 @@ static void handle_stripe(struct stripe_
set_bit(STRIPE_HANDLE, &sh->state);
}
+ // see if we have the data we need to expand by another block
+ if (conf->expand_in_progress && sh->disks == conf->previous_raid_disks) {
+ int uptodate = 0, delay_to_future=0, d = 0, needed_uptodate = 0;
+ spin_lock_irq(&conf->expand_progress_lock);
+ for (i=0; i<disks; ++i) {
+ sector_t start_sector, dest_sector;
+ unsigned int dd_idx, pd_idx;
+
+ if (i == sh->pd_idx)
+ continue;
+
+ // see what sector this block would land in the new layout
+ start_sector = compute_blocknr(sh, i);
+ dest_sector = raid5_compute_sector(start_sector, conf->raid_disks,
+ conf->raid_disks - 1, &dd_idx, &pd_idx, conf);
+ if (dd_idx > pd_idx)
+ --dd_idx;
+
+/* printk("start_sector = %llu (base=%llu, i=%u, d=%u) || dest_stripe = %llu\n", start_sector, sh->sector,
+ i, d, dest_stripe); */
+
+ if (dest_sector * (conf->raid_disks - 1) >= conf->expand_progress &&
+ dest_sector * (conf->raid_disks - 1) < conf->expand_progress + (conf->chunk_size >> 9) * (conf->raid_disks - 1)) {
+/* printk("UPDATING CHUNK %u FROM DISK %u (sec=%llu, dest_sector=%llu, uptodate=%u)\n",
+ dd_idx, i, start_sector, dest_sector, test_bit(R5_UPTODATE, &sh->dev[i].flags)); */
+ unsigned int ind = (start_sector - conf->expand_progress) / STRIPE_SECTORS;
+ if (test_bit(R5_UPTODATE, &sh->dev[i].flags)) {
+ unsigned int *ptr = page_address(conf->expand_buffer[ind].page);
+
+ conf->expand_buffer[ind].up_to_date = 1;
+ memcpy(page_address(conf->expand_buffer[ind].page), page_address(sh->dev[i].page), STRIPE_SIZE);
+// printk("memcpy done [%u -> %u]: %08x %08x %08x %08x\n", i, ind, ptr[0], ptr[1], ptr[2], ptr[3]);
+ } else {
+ conf->expand_buffer[ind].up_to_date = 0;
+ }
+ } else if (dest_sector * (conf->raid_disks - 1) >= conf->expand_progress + (conf->chunk_size >> 9) * (conf->raid_disks - 1) &&
+ dest_sector * (conf->raid_disks - 1) < conf->expand_progress + (conf->chunk_size >> 9) * (conf->raid_disks - 1) * 2 &&
+ syncing) {
+ delay_to_future = 1;
+ }
+ }
+ spin_unlock_irq(&conf->expand_progress_lock);
+
+ for (i=0; i < (conf->raid_disks - 1) * (conf->chunk_size / STRIPE_SIZE); ++i) {
+ uptodate += conf->expand_buffer[i].up_to_date;
+ }
+
+ /*
+ * Figure out how many stripes we need for this chunk to be complete.
+ * In almost all cases, this will be a full destination stripe, but our
+ * original volume might not be big enough for that at the very end --
+ * so use the rest of the volume then.
+ */
+ needed_uptodate = (conf->raid_disks - 1) * (conf->chunk_size / STRIPE_SIZE);
+ if (((conf->mddev->array_size << 1) - conf->expand_progress) / STRIPE_SECTORS < needed_uptodate) {
+ needed_uptodate = ((conf->mddev->array_size << 1) - conf->expand_progress) / STRIPE_SECTORS;
+// printk("reading partial block at the end: %u\n", needed_uptodate);
+ }
+ if (needed_uptodate > 0 && uptodate == needed_uptodate && conf->expand_stripes_ready == 1) {
+ // we can do an expand!
+ sector_t dest_sector, advance;
+ unsigned i;
+ unsigned int dummy1, dummy2, pd_idx, flags;
+
+ if ((conf->mddev->size << 1) - conf->expand_progress > (conf->chunk_size >> 9) * (conf->raid_disks - 1)) {
+ advance = (conf->chunk_size * (conf->raid_disks - 1)) >> 9;
+ } else {
+ advance = (conf->mddev->size << 1) - conf->expand_progress;
+ }
+
+ // find the parity disk and starting sector
+ dest_sector = raid5_compute_sector(conf->expand_progress, conf->raid_disks,
+ conf->raid_disks - 1, &dummy1, &pd_idx, conf);
+// printk("Expanding onto %llu\n", dest_sector);
+
+ spin_lock_irq(&conf->device_lock);
+
+ if (conf->expand_stripes_ready != 1) {
+ // something else just did the expand, we're done here
+ spin_unlock_irq(&conf->device_lock);
+ goto please_wait;
+ }
+
+ /*
+ * Check that we won't try to expand over an area where there's
+ * still active stripes; if we do, we'll risk inconsistency since we
+ * suddenly have two different sets of stripes referring to the
+ * same logical sector.
+ */
+ {
+ struct stripe_head *ash;
+ unsigned activity = 0, i;
+ sector_t first_touched_sector, last_touched_sector;
+
+ first_touched_sector = raid5_compute_sector(conf->expand_progress,
+ conf->previous_raid_disks, conf->previous_raid_disks - 1, &dummy1, &dummy2, conf);
+ last_touched_sector = raid5_compute_sector(conf->expand_progress + ((conf->chunk_size * (conf->previous_raid_disks - 1)) >> 9) - 1,
+ conf->previous_raid_disks, conf->previous_raid_disks - 1, &dummy1, &dummy2, conf);
+
+ for (i = 0; i < NR_HASH; i++) {
+ ash = conf->stripe_hashtbl[i];
+ for (; ash; ash = ash->hash_next) {
+ if (sh == ash && atomic_read(&ash->count) == 1 && !to_write)
+ continue; // we'll release it shortly, so it's OK (?)
+
+ // is this stripe active, and within the region we're expanding?
+ if (atomic_read(&ash->count) > 0 &&
+ ash->disks == conf->previous_raid_disks &&
+ ash->sector >= first_touched_sector &&
+ ash->sector <= last_touched_sector) {
+ ++activity;
+ }
+ }
+ }
+
+ if (activity > 0) {
+ printk("Aborting, %u active stripes in the area\n", activity);
+ spin_unlock_irq(&conf->device_lock);
+ goto please_wait;
+ }
+ }
+
+ spin_lock_irqsave(&conf->expand_progress_lock, flags);
+ conf->expand_progress += advance;
+
+ for (i = 0; i < conf->chunk_size / STRIPE_SIZE; ++i) {
+ struct stripe_head *newsh = conf->expand_stripes[i];
+ if (atomic_read(&newsh->count) != 0)
+ BUG();
+ init_stripe(newsh, dest_sector + i * STRIPE_SECTORS, pd_idx);
+ // printk("Generating sector %llu\n", dest_sector + i * STRIPE_SECTORS);
+
+ for (d = 0; d < conf->raid_disks; ++d) {
+ if (d == pd_idx) {
+ clear_bit(R5_UPTODATE, &newsh->dev[d].flags);
+ clear_bit(R5_LOCKED, &newsh->dev[d].flags);
+ } else {
+ unsigned int *ptr;
+ //struct page *tmp;
+ unsigned di;
+
+ di = (compute_blocknr(newsh, d) - (conf->expand_progress - advance)) / STRIPE_SECTORS;
+
+ // swap the two pages, moving the data in place into the stripe
+#if 0
+ // FIXME: this doesn't work. we'll need to fiddle with the bio_vec
+ // as well or we'll simply write out the wrong data.
+ tmp = newsh->dev[d].page;
+ newsh->dev[d].page = conf->expand_buffer[di].page;
+ conf->expand_buffer[di].page = tmp;
+#else
+ memcpy(page_address(newsh->dev[d].page), page_address(conf->expand_buffer[di].page), STRIPE_SIZE);
+#endif
+
+ ptr = page_address(newsh->dev[d].page);
+// printk("shuffle done [%u.%u -> %u]: %08x %08x %08x %08x\n", i, d, di, ptr[0], ptr[1], ptr[2], ptr[3]);
+
+ set_bit(R5_UPTODATE, &newsh->dev[d].flags);
+ set_bit(R5_LOCKED, &newsh->dev[d].flags);
+ conf->expand_buffer[di].up_to_date = 0;
+ }
+ set_bit(R5_Wantwrite, &newsh->dev[d].flags);
+ }
+ }
+ conf->expand_stripes_ready = 2;
+ spin_unlock_irqrestore(&conf->expand_progress_lock, flags);
+ spin_unlock_irq(&conf->device_lock);
+
+ for (i = 0; i < conf->chunk_size / STRIPE_SIZE; ++i) {
+ struct stripe_head *newsh = conf->expand_stripes[i];
+
+ compute_block(newsh, newsh->pd_idx);
+
+ spin_lock(&newsh->lock);
+ atomic_inc(&newsh->count);
+ clear_bit(STRIPE_SYNCING, &newsh->state);
+ set_bit(STRIPE_INSYNC, &newsh->state);
+ set_bit(STRIPE_HANDLE, &newsh->state);
+ spin_unlock(&newsh->lock);
+#if 0
+ printk("Releasing stripe %u (%u disks)\n", i, newsh->disks);
+ for (d = 0; d < conf->raid_disks; ++d) {
+ unsigned int *ptr = page_address(newsh->dev[d].page);
+ printk("%u: %08x %08x %08x %08x\n", d, ptr[0], ptr[1], ptr[2], ptr[3]);
+ }
+#endif
+ release_stripe(newsh);
+ }
+
+ conf->expand_stripes_ready = 0;
+
+ spin_lock_irq(&conf->device_lock);
+ md_done_sync(conf->mddev, advance, 1);
+ wake_up(&conf->wait_for_expand_progress);
+ spin_unlock_irq(&conf->device_lock);
+
+ // see if we have delayed data that we can process now
+ {
+ struct list_head *l, *next;
+
+ spin_lock_irq(&conf->device_lock);
+ l = conf->wait_for_expand_list.next;
+
+ while (l != &conf->wait_for_expand_list) {
+// int i, d = 0;
+ int do_process = 0;
+
+ struct stripe_head *dsh;
+ dsh = list_entry(l, struct stripe_head, lru);
+
+#if 0
+ for (i=0; i<disks; ++i) {
+ sector_t start_sector, dest_sector;
+ unsigned int dd_idx, pd_idx;
+
+ if (i == dsh->pd_idx)
+ continue;
+
+ start_sector = dsh->sector * (conf->previous_raid_disks - 1) + d * (conf->chunk_size >> 9);
+
+ // see what sector this block would land in in the new layout
+ dest_sector = raid5_compute_sector(start_sector, conf->raid_disks,
+ conf->raid_disks - 1, &dd_idx, &pd_idx, conf);
+ if (dest_sector * (conf->raid_disks - 1) < conf->expand_progress + (conf->raid_disks - 1) * (conf->chunk_size >> 9)) {
+ do_process = 1;
+ }
+
+ ++d;
+ }
+#endif
+
+ do_process = 1;
+ next = l->next;
+
+ if (do_process) {
+ list_del_init(l);
+
+ set_bit(STRIPE_HANDLE, &dsh->state);
+ clear_bit(STRIPE_DELAYED, &dsh->state);
+ clear_bit(STRIPE_DELAY_EXPAND, &dsh->state);
+ atomic_inc(&dsh->count);
+ __release_stripe(conf, dsh);
+ }
+
+ l = next;
+ }
+
+ spin_unlock_irq(&conf->device_lock);
+ }
+
+ // see if we are done
+ if (conf->expand_progress >= conf->mddev->array_size << 1) {
+ printk("Expand done, finishing...\n");
+ raid5_finish_expand(conf);
+ printk("...done.\n");
+ }
+
+please_wait:
+ 1;
+ }
+
+ if (delay_to_future) {
+ atomic_inc(&sh->count);
+ set_bit(STRIPE_DELAY_EXPAND, &sh->state);
+ }
+ }
+
/* now to consider writing and what else, if anything should be read */
if (to_write) {
int rmw=0, rcw=0;
@@ -1237,7 +1599,9 @@ static void handle_stripe(struct stripe_
}
}
if (syncing && locked == 0 && test_bit(STRIPE_INSYNC, &sh->state)) {
- md_done_sync(conf->mddev, STRIPE_SECTORS,1);
+ if (!conf->expand_in_progress) {
+ md_done_sync(conf->mddev, STRIPE_SECTORS,1);
+ }
clear_bit(STRIPE_SYNCING, &sh->state);
}
@@ -1279,7 +1643,7 @@ static void handle_stripe(struct stripe_
rcu_read_unlock();
if (rdev) {
- if (test_bit(R5_Syncio, &sh->dev[i].flags))
+ if (test_bit(R5_Syncio, &sh->dev[i].flags) && !conf->expand_in_progress)
md_sync_acct(rdev->bdev, STRIPE_SECTORS);
bi->bi_bdev = rdev->bdev;
@@ -1404,8 +1768,6 @@ static int make_request (request_queue_t
{
mddev_t *mddev = q->queuedata;
raid5_conf_t *conf = mddev_to_conf(mddev);
- const unsigned int raid_disks = conf->raid_disks;
- const unsigned int data_disks = raid_disks - 1;
unsigned int dd_idx, pd_idx;
sector_t new_sector;
sector_t logical_sector, last_sector;
@@ -1428,26 +1790,39 @@ static int make_request (request_queue_t
for (;logical_sector < last_sector; logical_sector += STRIPE_SECTORS) {
DEFINE_WAIT(w);
+ int disks;
+ recalculate:
+ if (conf->expand_in_progress && logical_sector >= conf->expand_progress) {
+ disks = conf->previous_raid_disks;
+ } else {
+ disks = conf->raid_disks;
+ }
new_sector = raid5_compute_sector(logical_sector,
- raid_disks, data_disks, &dd_idx, &pd_idx, conf);
-
- PRINTK("raid5: make_request, sector %llu logical %llu\n",
+ disks, disks - 1, &dd_idx, &pd_idx, conf);
+/* printk("raid5: make_request [%u/%u], sector %llu logical %llu\n",
+ dd_idx, disks,
(unsigned long long)new_sector,
- (unsigned long long)logical_sector);
+ (unsigned long long)logical_sector); */
retry:
prepare_to_wait(&conf->wait_for_overlap, &w, TASK_UNINTERRUPTIBLE);
sh = get_active_stripe(conf, new_sector, pd_idx, (bi->bi_rw&RWA_MASK));
- if (sh) {
- if (!add_stripe_bio(sh, bi, dd_idx, (bi->bi_rw&RW_MASK))) {
+ if (sh) {
+ if (sh->disks != disks || !add_stripe_bio(sh, bi, dd_idx, (bi->bi_rw&RW_MASK))) {
/* Add failed due to overlap. Flush everything
* and wait a while
*/
raid5_unplug_device(mddev->queue);
release_stripe(sh);
schedule();
- goto retry;
+ if (sh->disks != disks) {
+ // just expanded past this point! re-process using the new structure
+ printk("recalculate!\n");
+ finish_wait(&conf->wait_for_overlap, &w);
+ goto recalculate;
+ } else
+ goto retry;
}
finish_wait(&conf->wait_for_overlap, &w);
raid5_plug_device(conf);
@@ -1488,7 +1863,14 @@ static sector_t sync_request(mddev_t *md
sector_t first_sector;
int raid_disks = conf->raid_disks;
int data_disks = raid_disks-1;
+
+ if (conf->expand_in_progress) {
+ raid_disks = conf->previous_raid_disks;
+ data_disks = raid_disks-1;
+ }
+ BUG_ON(data_disks == 0 || raid_disks == 0);
+
if (sector_nr >= mddev->size <<1) {
/* just being told to finish up .. nothing much to do */
unplug_slaves(mddev);
@@ -1503,12 +1885,57 @@ static sector_t sync_request(mddev_t *md
*skipped = 1;
return rv;
}
+
+ /* if we're in an expand, we can't allow the process
+ * to keep reading in stripes; we might not have enough buffer
+ * space to keep it all in RAM.
+ */
+ if (conf->expand_in_progress && sector_nr >= conf->expand_progress + (conf->chunk_size >> 9) * (conf->raid_disks - 1)) {
+ spin_lock_irq(&conf->device_lock);
+ wait_event_lock_irq(conf->wait_for_expand_progress,
+ sector_nr < conf->expand_progress + (conf->chunk_size >> 9) * (conf->raid_disks - 1),
+ conf->device_lock,
+ unplug_slaves(conf->mddev);
+ );
+ spin_unlock_irq(&conf->device_lock);
+ }
+
+ /*
+ * In an expand, we also need to make sure that we have enough destination stripes
+ * available for writing out the block after we've read in the data, so make sure
+ * we get them before we start reading any data.
+ */
+ if (conf->expand_in_progress && conf->expand_stripes_ready == 0) {
+ unsigned i;
+
+ spin_lock_irq(&conf->device_lock);
+ for (i = 0; i < conf->chunk_size / STRIPE_SIZE; ++i) {
+ do {
+ conf->expand_stripes[i] = get_free_stripe(conf, 1);
+
+ if (conf->expand_stripes[i] == NULL) {
+ conf->inactive_blocked = 1;
+ wait_event_lock_irq(conf->wait_for_stripe,
+ !list_empty(&conf->inactive_list) &&
+ (atomic_read(&conf->active_stripes) < (NR_STRIPES *3/4)
+ || !conf->inactive_blocked),
+ conf->device_lock,
+ unplug_slaves(conf->mddev);
+ );
+ conf->inactive_blocked = 0;
+ }
+ } while (conf->expand_stripes[i] == NULL);
+ }
+ spin_unlock_irq(&conf->device_lock);
+
+ conf->expand_stripes_ready = 1;
+ }
x = sector_nr;
chunk_offset = sector_div(x, sectors_per_chunk);
stripe = x;
BUG_ON(x != stripe);
-
+
first_sector = raid5_compute_sector((sector_t)stripe*data_disks*sectors_per_chunk
+ chunk_offset, raid_disks, data_disks, &dd_idx, &pd_idx, conf);
sh = get_active_stripe(conf, sector_nr, pd_idx, 1);
@@ -1553,6 +1980,8 @@ static void raid5d (mddev_t *mddev)
while (1) {
struct list_head *first;
+ conf = mddev_to_conf(mddev);
+
if (list_empty(&conf->handle_list) &&
atomic_read(&conf->preread_active_stripes) < IO_THRESHOLD &&
!blk_queue_plugged(mddev->queue) &&
@@ -1600,7 +2029,7 @@ static int run (mddev_t *mddev)
}
mddev->private = kmalloc (sizeof (raid5_conf_t)
- + mddev->raid_disks * sizeof(struct disk_info),
+ + MAX_MD_DEVS * sizeof(struct disk_info),
GFP_KERNEL);
if ((conf = mddev->private) == NULL)
goto abort;
@@ -1650,6 +2079,7 @@ static int run (mddev_t *mddev)
conf->level = mddev->level;
conf->algorithm = mddev->layout;
conf->max_nr_stripes = NR_STRIPES;
+ conf->expand_in_progress = 0;
/* device size must be a multiple of chunk size */
mddev->size &= ~(mddev->chunk_size/1024 -1);
@@ -1866,6 +2296,9 @@ static int raid5_remove_disk(mddev_t *md
mdk_rdev_t *rdev;
struct disk_info *p = conf->disks + number;
+ printk("we were asked to remove a disk\n");
+ return -EBUSY; // FIXME: hack
+
print_raid5_conf(conf);
rdev = p->rdev;
if (rdev) {
@@ -1904,6 +2337,7 @@ static int raid5_add_disk(mddev_t *mddev
*/
for (disk=0; disk < mddev->raid_disks; disk++)
if ((p=conf->disks + disk)->rdev == NULL) {
+ rdev->faulty = 0;
rdev->in_sync = 0;
rdev->raid_disk = disk;
found = 1;
@@ -1916,6 +2350,7 @@ static int raid5_add_disk(mddev_t *mddev
static int raid5_resize(mddev_t *mddev, sector_t sectors)
{
+ raid5_conf_t *conf = mddev_to_conf(mddev);
/* no resync is happening, and there is enough space
* on all devices, so we can resize.
* We need to make sure resync covers any new space.
@@ -1923,6 +2358,9 @@ static int raid5_resize(mddev_t *mddev,
* any io in the removed space completes, but it hardly seems
* worth it.
*/
+ if (conf->expand_in_progress)
+ return -EBUSY;
+
sectors &= ~((sector_t)mddev->chunk_size/512 - 1);
mddev->array_size = (sectors * (mddev->raid_disks-1))>>1;
set_capacity(mddev->gendisk, mddev->array_size << 1);
@@ -1936,6 +2374,125 @@ static int raid5_resize(mddev_t *mddev,
return 0;
}
+static int raid5_reshape(mddev_t *mddev, int raid_disks)
+{
+ raid5_conf_t *conf = mddev_to_conf(mddev);
+ struct list_head *tmp;
+ mdk_rdev_t *rdev;
+ unsigned long flags;
+
+ int d, i;
+
+ if (mddev->degraded >= 1 || conf->expand_in_progress)
+ return -EBUSY;
+ if (conf->raid_disks == raid_disks)
+ return 0;
+
+ print_raid5_conf(conf);
+
+ // the old stripes are too small now; remove them (temporarily
+ // stalling the RAID)
+ for (i = 0; i < conf->max_nr_stripes; ++i) {
+ struct stripe_head *sh;
+
+ spin_lock_irqsave(&conf->device_lock, flags);
+ sh = get_free_stripe(conf, 0);
+ while (sh == NULL) {
+ wait_event_lock_irq(conf->wait_for_stripe,
+ !list_empty(&conf->inactive_list),
+ conf->device_lock,
+ unplug_slaves(conf->mddev);
+ );
+ sh = get_free_stripe(conf, 0);
+ }
+ spin_unlock_irqrestore(&conf->device_lock, flags);
+
+ shrink_buffers(sh, conf->raid_disks);
+ kmem_cache_free(conf->slab_cache, sh);
+ atomic_dec(&conf->active_stripes);
+ }
+ kmem_cache_destroy(conf->slab_cache);
+
+ spin_lock_irqsave(&conf->device_lock, flags);
+
+ for (d= conf->raid_disks; d < MAX_MD_DEVS; d++) {
+ conf->disks[d].rdev = NULL;
+ }
+
+ conf->expand_in_progress = 1;
+ conf->expand_progress = 0;
+ conf->previous_raid_disks = conf->raid_disks;
+ conf->raid_disks = mddev->raid_disks = raid_disks;
+
+ spin_lock_init(&conf->expand_progress_lock);
+
+ init_waitqueue_head(&conf->wait_for_expand_progress);
+ INIT_LIST_HEAD(&conf->wait_for_expand_list);
+
+ ITERATE_RDEV(mddev,rdev,tmp) {
+ for (d= 0; d < conf->raid_disks; d++) {
+ if (conf->disks[d].rdev == rdev) {
+ goto already_there;
+ }
+ }
+
+ raid5_add_disk(mddev, rdev);
+ conf->failed_disks++;
+
+already_there:
+ 1;
+ }
+
+ spin_unlock_irqrestore(&conf->device_lock, flags);
+
+ // allocate stripes of the new size
+ if (grow_stripes(conf, conf->max_nr_stripes)) {
+ BUG(); // FIXME
+ return -ENOMEM;
+ }
+
+ // allocate space for our temporary expansion buffers
+ conf->expand_buffer = kmalloc (sizeof(struct expand_buf) * (conf->chunk_size / STRIPE_SIZE) * (raid_disks-1), GFP_KERNEL);
+ if (conf->expand_buffer == NULL) {
+ printk(KERN_ERR "raid5: couldn't allocate %dkB for expand buffer\n",
+ (conf->chunk_size * (raid_disks-1)) >> 10);
+ // FIXME
+ return -ENOMEM;
+ }
+
+ conf->expand_stripes = kmalloc (sizeof(struct stripe_head *) * (conf->chunk_size / STRIPE_SIZE), GFP_KERNEL);
+ if (conf->expand_stripes == NULL) {
+ printk(KERN_ERR "raid5: couldn't allocate memory for expand stripe pointers\n");
+ // FIXME
+ return -ENOMEM;
+ }
+ conf->expand_stripes_ready = 0;
+
+ for (i = 0; i < (conf->chunk_size / STRIPE_SIZE) * (raid_disks-1); ++i) {
+ conf->expand_buffer[i].page = alloc_page(GFP_KERNEL);
+ if (conf->expand_buffer[i].page == NULL) {
+ printk(KERN_ERR "raid5: couldn't allocate %dkB for expand buffer\n",
+ (conf->chunk_size * (raid_disks-1)) >> 10);
+ // FIXME
+ return -ENOMEM;
+ }
+ conf->expand_buffer[i].up_to_date = 0;
+ }
+
+ print_raid5_conf(conf);
+
+ clear_bit(MD_RECOVERY_DONE, &mddev->recovery);
+ set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
+ set_bit(MD_RECOVERY_SYNC, &mddev->recovery);
+ mddev->recovery_cp = 0;
+ md_wakeup_thread(mddev->thread);
+
+ printk("Starting expand.\n");
+
+ return 0;
+}
+
+
static mdk_personality_t raid5_personality=
{
.name = "raid5",
@@ -1950,6 +2507,7 @@ static mdk_personality_t raid5_personali
.spare_active = raid5_spare_active,
.sync_request = sync_request,
.resize = raid5_resize,
+ .reshape = raid5_reshape
};
static int __init raid5_init (void)
--- /usr/src/old/linux-2.6.13/include/linux/raid/raid5.h 2005-08-29 01:41:01.000000000 +0200
+++ include/linux/raid/raid5.h 2005-10-14 21:28:42.000000000 +0200
@@ -134,6 +134,7 @@ struct stripe_head {
unsigned long state; /* state flags */
atomic_t count; /* nr of active thread/requests */
spinlock_t lock;
+ int disks; /* disks in stripe */
struct r5dev {
struct bio req;
struct bio_vec vec;
@@ -171,6 +172,7 @@ struct stripe_head {
#define STRIPE_INSYNC 4
#define STRIPE_PREREAD_ACTIVE 5
#define STRIPE_DELAYED 6
+#define STRIPE_DELAY_EXPAND 7
/*
* Plugging:
@@ -199,6 +201,10 @@ struct stripe_head {
struct disk_info {
mdk_rdev_t *rdev;
};
+struct expand_buf {
+ struct page *page;
+ int up_to_date;
+};
struct raid5_private_data {
struct stripe_head **stripe_hashtbl;
@@ -208,22 +214,38 @@ struct raid5_private_data {
int raid_disks, working_disks, failed_disks;
int max_nr_stripes;
+ /* used during an expand */
+ int expand_in_progress;
+ sector_t expand_progress;
+ spinlock_t expand_progress_lock;
+ int previous_raid_disks;
+ struct list_head wait_for_expand_list;
+
+ struct expand_buf *expand_buffer;
+
+ int expand_stripes_ready;
+ struct stripe_head **expand_stripes;
+
struct list_head handle_list; /* stripes needing handling */
struct list_head delayed_list; /* stripes that have plugged requests */
atomic_t preread_active_stripes; /* stripes with scheduled io */
char cache_name[20];
+ char cache_name_expand[20];
kmem_cache_t *slab_cache; /* for allocating stripes */
+
/*
* Free stripes pool
*/
atomic_t active_stripes;
struct list_head inactive_list;
wait_queue_head_t wait_for_stripe;
+ wait_queue_head_t wait_for_expand_progress;
wait_queue_head_t wait_for_overlap;
int inactive_blocked; /* release of inactive stripes blocked,
* waiting for 25% to be free
- */
+ */
+ int inactive_blocked_expand;
spinlock_t device_lock;
struct disk_info disks[0];
};
