This patch implements async writes in raid1.
Signed-Off-By: Paul Clements <paul.clements@xxxxxxxxxxxx>
drivers/md/raid1.c | 107 ++++++++++++++++++++++++++++++++++++++++++---
include/linux/raid/raid1.h | 2
2 files changed, 102 insertions(+), 7 deletions(-)
diff -purN --exclude core --exclude-from /export/public/clemep/tmp/dontdiff linux-2.6.11-rc3-mm2-patch-all-write-mostly-max-dev-bug-bitmap-bug-fix/drivers/md/raid1.c linux-2.6.11-rc3-mm2-patch-all-write-mostly-async-write-bitmap-bug-fix/drivers/md/raid1.c
--- linux-2.6.11-rc3-mm2-patch-all-write-mostly-max-dev-bug-bitmap-bug-fix/drivers/md/raid1.c Thu Mar 10 10:05:35 2005
+++ linux-2.6.11-rc3-mm2-patch-all-write-mostly-async-write-bitmap-bug-fix/drivers/md/raid1.c Sat Mar 12 08:38:20 2005
@@ -35,7 +35,7 @@
#include <linux/raid/raid1.h>
#include <linux/raid/bitmap.h>
-#define DEBUG 0
+#define DEBUG 0
#if DEBUG
#define PRINTK(x...) printk(x)
#else
@@ -222,8 +222,17 @@ static void raid_end_bio_io(r1bio_t *r1_
{
struct bio *bio = r1_bio->master_bio;
- bio_endio(bio, bio->bi_size,
- test_bit(R1BIO_Uptodate, &r1_bio->state) ? 0 : -EIO);
+ /* if nobody has done the final endio yet, do it now */
+ if (!test_and_set_bit(R1BIO_AsyncPhase, &r1_bio->state)) {
+ PRINTK(KERN_DEBUG "raid1: sync end %s on sectors %llu-%llu\n",
+ (bio_data_dir(bio) == WRITE) ? "write" : "read",
+ (unsigned long long) bio->bi_sector,
+ (unsigned long long) bio->bi_sector +
+ (bio->bi_size >> 9) - 1);
+
+ bio_endio(bio, bio->bi_size,
+ test_bit(R1BIO_Uptodate, &r1_bio->state) ? 0 : -EIO);
+ }
free_r1bio(r1_bio);
}
@@ -292,7 +301,7 @@ static int raid1_end_write_request(struc
{
int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
r1bio_t * r1_bio = (r1bio_t *)(bio->bi_private);
- int mirror;
+ int mirror, async, wonly = 1; /* assume write only if rdev missing */
conf_t *conf = mddev_to_conf(r1_bio->mddev);
if (bio->bi_size)
@@ -323,16 +332,39 @@ static int raid1_end_write_request(struc
update_head_pos(mirror, r1_bio);
+ async = test_bit(R1BIO_AsyncIO, &r1_bio->state);
+ if (conf->mirrors[mirror].rdev)
+ wonly = test_bit(WriteMostly, &conf->mirrors[mirror].rdev->flags);
+ /* In async mode, we ACK the master bio once the I/O has safely
+ * reached the non-writeonly disk. Setting the AsyncPhase bit
+ * ensures that this gets done only once -- we don't ever want to
+ * return -EIO here, instead we'll wait */
+ if (async && !wonly && test_bit(R1BIO_Uptodate, &r1_bio->state) &&
+ !test_and_set_bit(R1BIO_AsyncPhase, &r1_bio->state)) {
+ struct bio *mbio = r1_bio->master_bio;
+ PRINTK(KERN_DEBUG "raid1: async end write sectors %llu-%llu\n",
+ (unsigned long long) mbio->bi_sector,
+ (unsigned long long) mbio->bi_sector +
+ (mbio->bi_size >> 9) - 1);
+ bio_endio(mbio, mbio->bi_size, 0);
+ }
/*
*
* Let's see if all mirrored write operations have finished
* already.
*/
if (atomic_dec_and_test(&r1_bio->remaining)) {
+ if (async) {
+ int i = bio->bi_vcnt;
+ /* free extra copy of the data pages */
+ while (i--)
+ __free_page(bio->bi_io_vec[i].bv_page);
+ }
/* clear the bitmap if all writes complete successfully */
bitmap_endwrite(r1_bio->mddev->bitmap, r1_bio->sector,
r1_bio->sectors,
- !test_bit(R1BIO_Degraded, &r1_bio->state));
+ !test_bit(R1BIO_Degraded, &r1_bio->state),
+ async);
md_write_end(r1_bio->mddev);
raid_end_bio_io(r1_bio);
}
@@ -553,6 +585,38 @@ static void device_barrier(conf_t *conf,
spin_unlock_irq(&conf->resync_lock);
}
+/* duplicate the data pages for async I/O */
+static struct page **alloc_async_pages(struct bio *bio)
+{
+ int i;
+ struct bio_vec *bvec;
+ struct page **pages = kmalloc(bio->bi_vcnt * sizeof(struct page *),
+ GFP_NOIO);
+ if (unlikely(!pages))
+ goto do_sync_io;
+
+ BUG_ON(bio->bi_idx != 0);
+ bio_for_each_segment(bvec, bio, i) {
+ pages[i] = alloc_page(GFP_NOIO);
+ if (unlikely(!pages[i]))
+ goto do_sync_io;
+ memcpy(kmap(pages[i]) + bvec->bv_offset,
+ kmap(bvec->bv_page) + bvec->bv_offset, bvec->bv_len);
+ kunmap(pages[i]);
+ kunmap(bvec->bv_page);
+ }
+
+ return pages;
+
+do_sync_io:
+ if (pages)
+ for (i = 0; i < bio->bi_vcnt && pages[i]; i++)
+ __free_page(pages[i]);
+ kfree(pages);
+ PRINTK("%dB async alloc failed, doing sync I/O\n", bio->bi_size);
+ return NULL;
+}
+
static int make_request(request_queue_t *q, struct bio * bio)
{
mddev_t *mddev = q->queuedata;
@@ -565,6 +629,7 @@ static int make_request(request_queue_t
struct bitmap *bitmap = mddev->bitmap;
unsigned long flags;
struct bio_list bl;
+ struct page **async_pages = NULL;
/*
@@ -668,6 +733,12 @@ static int make_request(request_queue_t
set_bit(R1BIO_Degraded, &r1_bio->state);
}
+ /* do async I/O ? */
+ if (bitmap &&
+ atomic_read(&bitmap->async_writes) < bitmap->async_max_writes &&
+ (async_pages = alloc_async_pages(bio)))
+ set_bit(R1BIO_AsyncIO, &r1_bio->state);
+
atomic_set(&r1_bio->remaining, 0);
bio_list_init(&bl);
@@ -685,19 +756,30 @@ static int make_request(request_queue_t
mbio->bi_rw = WRITE;
mbio->bi_private = r1_bio;
+ if (test_bit(R1BIO_AsyncIO, &r1_bio->state)) {
+ struct bio_vec *bvec;
+ int j;
+
+ BUG_ON(!async_pages);
+ bio_for_each_segment(bvec, mbio, j)
+ bvec->bv_page = async_pages[j];
+ }
+
atomic_inc(&r1_bio->remaining);
bio_list_add(&bl, mbio);
}
+ kfree(async_pages); /* the async pages are attached to the bios now */
- bitmap_startwrite(bitmap, bio->bi_sector, r1_bio->sectors);
+ bitmap_startwrite(bitmap, bio->bi_sector, r1_bio->sectors,
+ test_bit(R1BIO_AsyncIO, &r1_bio->state));
spin_lock_irqsave(&conf->device_lock, flags);
bio_list_merge(&conf->pending_bio_list, &bl);
bio_list_init(&bl);
blk_plug_device(mddev->queue);
spin_unlock_irqrestore(&conf->device_lock, flags);
-
+
#if 0
while ((bio = bio_list_pop(&bl)) != NULL)
generic_make_request(bio);
@@ -1458,6 +1540,17 @@ out:
static int stop(mddev_t *mddev)
{
conf_t *conf = mddev_to_conf(mddev);
+ struct bitmap *bitmap = mddev->bitmap;
+ int async_wait = 0;
+
+ /* wait for async writes to complete */
+ while (bitmap && atomic_read(&bitmap->async_writes) > 0) {
+ async_wait++;
+ printk(KERN_INFO "raid1: async writes in progress on device %s, waiting to stop (%d)\n", mdname(mddev), async_wait);
+ set_current_state(TASK_UNINTERRUPTIBLE);
+ schedule_timeout(HZ); /* wait a second */
+ /* need to kick something here to make sure I/O goes? */
+ }
md_unregister_thread(mddev->thread);
mddev->thread = NULL;
diff -purN --exclude core --exclude-from /export/public/clemep/tmp/dontdiff linux-2.6.11-rc3-mm2-patch-all-write-mostly-max-dev-bug-bitmap-bug-fix/include/linux/raid/raid1.h linux-2.6.11-rc3-mm2-patch-all-write-mostly-async-write-bitmap-bug-fix/include/linux/raid/raid1.h
--- linux-2.6.11-rc3-mm2-patch-all-write-mostly-max-dev-bug-bitmap-bug-fix/include/linux/raid/raid1.h Fri Feb 18 14:45:25 2005
+++ linux-2.6.11-rc3-mm2-patch-all-write-mostly-async-write-bitmap-bug-fix/include/linux/raid/raid1.h Mon Feb 21 16:48:38 2005
@@ -107,4 +107,6 @@ struct r1bio_s {
#define R1BIO_Uptodate 0
#define R1BIO_IsSync 1
#define R1BIO_Degraded 2
+#define R1BIO_AsyncPhase 3
+#define R1BIO_AsyncIO 4
#endif
