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Diffstat (limited to 'drivers/md/raid5.c')
-rw-r--r--drivers/md/raid5.c84
1 files changed, 58 insertions, 26 deletions
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index 7433871f4b3a..450066007160 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -18,6 +18,30 @@
* Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
+/*
+ * BITMAP UNPLUGGING:
+ *
+ * The sequencing for updating the bitmap reliably is a little
+ * subtle (and I got it wrong the first time) so it deserves some
+ * explanation.
+ *
+ * We group bitmap updates into batches. Each batch has a number.
+ * We may write out several batches at once, but that isn't very important.
+ * conf->bm_write is the number of the last batch successfully written.
+ * conf->bm_flush is the number of the last batch that was closed to
+ * new additions.
+ * When we discover that we will need to write to any block in a stripe
+ * (in add_stripe_bio) we update the in-memory bitmap and record in sh->bm_seq
+ * the number of the batch it will be in. This is bm_flush+1.
+ * When we are ready to do a write, if that batch hasn't been written yet,
+ * we plug the array and queue the stripe for later.
+ * When an unplug happens, we increment bm_flush, thus closing the current
+ * batch.
+ * When we notice that bm_flush > bm_write, we write out all pending updates
+ * to the bitmap, and advance bm_write to where bm_flush was.
+ * This may occasionally write a bit out twice, but is sure never to
+ * miss any bits.
+ */
#include <linux/module.h>
#include <linux/slab.h>
@@ -88,12 +112,14 @@ static void __release_stripe(raid5_conf_t *conf, struct stripe_head *sh)
BUG_ON(!list_empty(&sh->lru));
BUG_ON(atomic_read(&conf->active_stripes)==0);
if (test_bit(STRIPE_HANDLE, &sh->state)) {
- if (test_bit(STRIPE_DELAYED, &sh->state))
+ if (test_bit(STRIPE_DELAYED, &sh->state)) {
list_add_tail(&sh->lru, &conf->delayed_list);
- else if (test_bit(STRIPE_BIT_DELAY, &sh->state) &&
- conf->seq_write == sh->bm_seq)
+ blk_plug_device(conf->mddev->queue);
+ } else if (test_bit(STRIPE_BIT_DELAY, &sh->state) &&
+ sh->bm_seq - conf->seq_write > 0) {
list_add_tail(&sh->lru, &conf->bitmap_list);
- else {
+ blk_plug_device(conf->mddev->queue);
+ } else {
clear_bit(STRIPE_BIT_DELAY, &sh->state);
list_add_tail(&sh->lru, &conf->handle_list);
}
@@ -270,7 +296,7 @@ static struct stripe_head *get_active_stripe(raid5_conf_t *conf, sector_t sector
< (conf->max_nr_stripes *3/4)
|| !conf->inactive_blocked),
conf->device_lock,
- unplug_slaves(conf->mddev)
+ raid5_unplug_device(conf->mddev->queue)
);
conf->inactive_blocked = 0;
} else
@@ -281,7 +307,8 @@ static struct stripe_head *get_active_stripe(raid5_conf_t *conf, sector_t sector
} else {
if (!test_bit(STRIPE_HANDLE, &sh->state))
atomic_inc(&conf->active_stripes);
- if (list_empty(&sh->lru))
+ if (list_empty(&sh->lru) &&
+ !test_bit(STRIPE_EXPANDING, &sh->state))
BUG();
list_del_init(&sh->lru);
}
@@ -496,6 +523,8 @@ static int raid5_end_read_request(struct bio * bi, unsigned int bytes_done,
raid5_conf_t *conf = sh->raid_conf;
int disks = sh->disks, i;
int uptodate = test_bit(BIO_UPTODATE, &bi->bi_flags);
+ char b[BDEVNAME_SIZE];
+ mdk_rdev_t *rdev;
if (bi->bi_size)
return 1;
@@ -543,25 +572,39 @@ static int raid5_end_read_request(struct bio * bi, unsigned int bytes_done,
set_bit(R5_UPTODATE, &sh->dev[i].flags);
#endif
if (test_bit(R5_ReadError, &sh->dev[i].flags)) {
- printk(KERN_INFO "raid5: read error corrected!!\n");
+ rdev = conf->disks[i].rdev;
+ printk(KERN_INFO "raid5:%s: read error corrected (%lu sectors at %llu on %s)\n",
+ mdname(conf->mddev), STRIPE_SECTORS,
+ (unsigned long long)sh->sector + rdev->data_offset,
+ bdevname(rdev->bdev, b));
clear_bit(R5_ReadError, &sh->dev[i].flags);
clear_bit(R5_ReWrite, &sh->dev[i].flags);
}
if (atomic_read(&conf->disks[i].rdev->read_errors))
atomic_set(&conf->disks[i].rdev->read_errors, 0);
} else {
+ const char *bdn = bdevname(conf->disks[i].rdev->bdev, b);
int retry = 0;
+ rdev = conf->disks[i].rdev;
+
clear_bit(R5_UPTODATE, &sh->dev[i].flags);
- atomic_inc(&conf->disks[i].rdev->read_errors);
+ atomic_inc(&rdev->read_errors);
if (conf->mddev->degraded)
- printk(KERN_WARNING "raid5: read error not correctable.\n");
+ printk(KERN_WARNING "raid5:%s: read error not correctable (sector %llu on %s).\n",
+ mdname(conf->mddev),
+ (unsigned long long)sh->sector + rdev->data_offset,
+ bdn);
else if (test_bit(R5_ReWrite, &sh->dev[i].flags))
/* Oh, no!!! */
- printk(KERN_WARNING "raid5: read error NOT corrected!!\n");
- else if (atomic_read(&conf->disks[i].rdev->read_errors)
+ printk(KERN_WARNING "raid5:%s: read error NOT corrected!! (sector %llu on %s).\n",
+ mdname(conf->mddev),
+ (unsigned long long)sh->sector + rdev->data_offset,
+ bdn);
+ else if (atomic_read(&rdev->read_errors)
> conf->max_nr_stripes)
printk(KERN_WARNING
- "raid5: Too many read errors, failing device.\n");
+ "raid5:%s: Too many read errors, failing device %s.\n",
+ mdname(conf->mddev), bdn);
else
retry = 1;
if (retry)
@@ -569,7 +612,7 @@ static int raid5_end_read_request(struct bio * bi, unsigned int bytes_done,
else {
clear_bit(R5_ReadError, &sh->dev[i].flags);
clear_bit(R5_ReWrite, &sh->dev[i].flags);
- md_error(conf->mddev, conf->disks[i].rdev);
+ md_error(conf->mddev, rdev);
}
}
rdev_dec_pending(conf->disks[i].rdev, conf->mddev);
@@ -1270,9 +1313,9 @@ static int add_stripe_bio(struct stripe_head *sh, struct bio *bi, int dd_idx, in
(unsigned long long)sh->sector, dd_idx);
if (conf->mddev->bitmap && firstwrite) {
- sh->bm_seq = conf->seq_write;
bitmap_startwrite(conf->mddev->bitmap, sh->sector,
STRIPE_SECTORS, 0);
+ sh->bm_seq = conf->seq_flush+1;
set_bit(STRIPE_BIT_DELAY, &sh->state);
}
@@ -2554,13 +2597,6 @@ static int raid5_issue_flush(request_queue_t *q, struct gendisk *disk,
return ret;
}
-static inline void raid5_plug_device(raid5_conf_t *conf)
-{
- spin_lock_irq(&conf->device_lock);
- blk_plug_device(conf->mddev->queue);
- spin_unlock_irq(&conf->device_lock);
-}
-
static int make_request(request_queue_t *q, struct bio * bi)
{
mddev_t *mddev = q->queuedata;
@@ -2670,7 +2706,6 @@ static int make_request(request_queue_t *q, struct bio * bi)
goto retry;
}
finish_wait(&conf->wait_for_overlap, &w);
- raid5_plug_device(conf);
handle_stripe(sh, NULL);
release_stripe(sh);
} else {
@@ -2923,7 +2958,7 @@ static void raid5d (mddev_t *mddev)
while (1) {
struct list_head *first;
- if (conf->seq_flush - conf->seq_write > 0) {
+ if (conf->seq_flush != conf->seq_write) {
int seq = conf->seq_flush;
spin_unlock_irq(&conf->device_lock);
bitmap_unplug(mddev->bitmap);
@@ -3246,9 +3281,6 @@ static int run(mddev_t *mddev)
set_bit(MD_RECOVERY_RUNNING, &mddev->recovery);
mddev->sync_thread = md_register_thread(md_do_sync, mddev,
"%s_reshape");
- /* FIXME if md_register_thread fails?? */
- md_wakeup_thread(mddev->sync_thread);
-
}
/* read-ahead size must cover two whole stripes, which is
generated by cgit v1.2.3 (git 2.0.4) at 2024-11-09 05:53:23 +0000