1/ rationalise read_balance and "map" in raid1. Discard map and
tidyup the interface to read_balance so it can be used instead.
2/ use offsetof rather than a caclulation to find the size of an
structure with a var-length array at the end.
3/ remove some meaningless #defines
4/ use printk_ratelimit to limit reports of failed sectors being redirected.
Signed-off-by: Neil Brown <neilb@xxxxxxxxxxxxxxx>
### Diffstat output
./drivers/md/raid1.c | 89 ++++++++++++++++++++-------------------------------
1 files changed, 36 insertions(+), 53 deletions(-)
diff ./drivers/md/raid1.c~current~ ./drivers/md/raid1.c
--- ./drivers/md/raid1.c~current~ 2004-08-23 12:20:59.000000000 +1000
+++ ./drivers/md/raid1.c 2004-08-23 12:31:36.000000000 +1000
@@ -24,10 +24,6 @@
#include <linux/raid/raid1.h>
-#define MAJOR_NR MD_MAJOR
-#define MD_DRIVER
-#define MD_PERSONALITY
-
/*
* Number of guaranteed r1bios in case of extreme VM load:
*/
@@ -44,13 +40,12 @@ static void * r1bio_pool_alloc(int gfp_f
{
struct pool_info *pi = data;
r1bio_t *r1_bio;
+ int size = offsetof(r1bio_t, bios[pi->raid_disks]);
/* allocate a r1bio with room for raid_disks entries in the bios array */
- r1_bio = kmalloc(sizeof(r1bio_t) + sizeof(struct bio*)*pi->raid_disks,
- gfp_flags);
+ r1_bio = kmalloc(size, gfp_flags);
if (r1_bio)
- memset(r1_bio, 0, sizeof(*r1_bio) +
- sizeof(struct bio*) * pi->raid_disks);
+ memset(r1_bio, 0, size);
else
unplug_slaves(pi->mddev);
@@ -104,7 +99,7 @@ static void * r1buf_pool_alloc(int gfp_f
bio->bi_io_vec[i].bv_page = page;
}
- r1_bio->master_bio = bio;
+ r1_bio->master_bio = NULL;
return r1_bio;
@@ -189,32 +184,6 @@ static inline void put_buf(r1bio_t *r1_b
spin_unlock_irqrestore(&conf->resync_lock, flags);
}
-static int map(mddev_t *mddev, mdk_rdev_t **rdevp)
-{
- conf_t *conf = mddev_to_conf(mddev);
- int i, disks = conf->raid_disks;
-
- /*
- * Later we do read balancing on the read side
- * now we use the first available disk.
- */
-
- spin_lock_irq(&conf->device_lock);
- for (i = 0; i < disks; i++) {
- mdk_rdev_t *rdev = conf->mirrors[i].rdev;
- if (rdev && rdev->in_sync) {
- *rdevp = rdev;
- atomic_inc(&rdev->nr_pending);
- spin_unlock_irq(&conf->device_lock);
- return i;
- }
- }
- spin_unlock_irq(&conf->device_lock);
-
- printk(KERN_ERR "raid1_map(): huh, no more operational devices?\n");
- return -1;
-}
-
static void reschedule_retry(r1bio_t *r1_bio)
{
unsigned long flags;
@@ -292,8 +261,9 @@ static int raid1_end_read_request(struct
* oops, read error:
*/
char b[BDEVNAME_SIZE];
- printk(KERN_ERR "raid1: %s: rescheduling sector %llu\n",
- bdevname(conf->mirrors[mirror].rdev->bdev,b), (unsigned long long)r1_bio->sector);
+ if (printk_ratelimit())
+ printk(KERN_ERR "raid1: %s: rescheduling sector %llu\n",
+ bdevname(conf->mirrors[mirror].rdev->bdev,b), (unsigned long long)r1_bio->sector);
reschedule_retry(r1_bio);
}
@@ -363,11 +333,11 @@ static int raid1_end_write_request(struc
*
* The rdev for the device selected will have nr_pending incremented.
*/
-static int read_balance(conf_t *conf, struct bio *bio, r1bio_t *r1_bio)
+static int read_balance(conf_t *conf, r1bio_t *r1_bio)
{
const unsigned long this_sector = r1_bio->sector;
int new_disk = conf->last_used, disk = new_disk;
- const int sectors = bio->bi_size >> 9;
+ const int sectors = r1_bio->sectors;
sector_t new_distance, current_distance;
spin_lock_irq(&conf->device_lock);
@@ -378,14 +348,14 @@ static int read_balance(conf_t *conf, st
*/
if (conf->mddev->recovery_cp < MaxSector &&
(this_sector + sectors >= conf->next_resync)) {
- /* make sure that disk is operational */
+ /* Choose the first operation device, for consistancy */
new_disk = 0;
while (!conf->mirrors[new_disk].rdev ||
!conf->mirrors[new_disk].rdev->in_sync) {
new_disk++;
if (new_disk == conf->raid_disks) {
- new_disk = 0;
+ new_disk = -1;
break;
}
}
@@ -400,7 +370,7 @@ static int read_balance(conf_t *conf, st
new_disk = conf->raid_disks;
new_disk--;
if (new_disk == disk) {
- new_disk = conf->last_used;
+ new_disk = -1;
goto rb_out;
}
}
@@ -440,13 +410,13 @@ static int read_balance(conf_t *conf, st
} while (disk != conf->last_used);
rb_out:
- r1_bio->read_disk = new_disk;
- conf->next_seq_sect = this_sector + sectors;
- conf->last_used = new_disk;
- if (conf->mirrors[new_disk].rdev)
+ if (new_disk >= 0) {
+ conf->next_seq_sect = this_sector + sectors;
+ conf->last_used = new_disk;
atomic_inc(&conf->mirrors[new_disk].rdev->nr_pending);
+ }
spin_unlock_irq(&conf->device_lock);
return new_disk;
@@ -571,15 +541,26 @@ static int make_request(request_queue_t
r1_bio->mddev = mddev;
r1_bio->sector = bio->bi_sector;
+ r1_bio->state = 0;
+
if (bio_data_dir(bio) == READ) {
/*
* read balancing logic:
*/
- mirror = conf->mirrors + read_balance(conf, bio, r1_bio);
+ int rdisk = read_balance(conf, r1_bio);
+
+ if (rdisk < 0) {
+ /* couldn't find anywhere to read from */
+ raid_end_bio_io(r1_bio);
+ return 0;
+ }
+ mirror = conf->mirrors + rdisk;
+
+ r1_bio->read_disk = rdisk;
read_bio = bio_clone(bio, GFP_NOIO);
- r1_bio->bios[r1_bio->read_disk] = read_bio;
+ r1_bio->bios[rdisk] = read_bio;
read_bio->bi_sector = r1_bio->sector + mirror->rdev->data_offset;
read_bio->bi_bdev = mirror->rdev->bdev;
@@ -951,7 +932,7 @@ static void raid1d(mddev_t *mddev)
} else {
int disk;
bio = r1_bio->bios[r1_bio->read_disk];
- if ((disk=map(mddev, &rdev)) == -1) {
+ if ((disk=read_balance(conf, r1_bio)) == -1) {
printk(KERN_ALERT "raid1: %s: unrecoverable I/O"
" read error for block %llu\n",
bdevname(bio->bi_bdev,b),
@@ -961,10 +942,12 @@ static void raid1d(mddev_t *mddev)
r1_bio->bios[r1_bio->read_disk] = NULL;
r1_bio->read_disk = disk;
r1_bio->bios[r1_bio->read_disk] = bio;
- printk(KERN_ERR "raid1: %s: redirecting sector %llu to"
- " another mirror\n",
- bdevname(rdev->bdev,b),
- (unsigned long long)r1_bio->sector);
+ rdev = conf->mirrors[disk].rdev;
+ if (printk_ratelimit())
+ printk(KERN_ERR "raid1: %s: redirecting sector %llu to"
+ " another mirror\n",
+ bdevname(rdev->bdev,b),
+ (unsigned long long)r1_bio->sector);
bio->bi_bdev = rdev->bdev;
bio->bi_sector = r1_bio->sector + rdev->data_offset;
bio->bi_rw = READ;
-
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