md/multipath has two separate pieces of code for choosing a device
to use, one when a request is first made and the other when a
request is being re-tried after failure.
This patch discards multipath_read_balance and uses multipath_map
in both situations.
Signed-off-by: Neil Brown <neilb@xxxxxxxxxxxxxxx>
----------- Diffstat output ------------
./drivers/md/multipath.c | 45 ++++++++++++---------------------------------
1 files changed, 12 insertions(+), 33 deletions(-)
diff ./drivers/md/multipath.c~current~ ./drivers/md/multipath.c
--- ./drivers/md/multipath.c~current~ 2004-05-28 15:47:47.000000000 +1000
+++ ./drivers/md/multipath.c 2004-05-28 15:47:47.000000000 +1000
@@ -54,9 +54,8 @@ static void mp_pool_free(void *mpb, void
kfree(mpb);
}
-static int multipath_map (mddev_t *mddev, mdk_rdev_t **rdevp)
+static int multipath_map (multipath_conf_t *conf)
{
- multipath_conf_t *conf = mddev_to_conf(mddev);
int i, disks = conf->raid_disks;
/*
@@ -68,10 +67,9 @@ static int multipath_map (mddev_t *mddev
for (i = 0; i < disks; i++) {
mdk_rdev_t *rdev = conf->multipaths[i].rdev;
if (rdev && rdev->in_sync) {
- *rdevp = rdev;
atomic_inc(&rdev->nr_pending);
spin_unlock_irq(&conf->device_lock);
- return 0;
+ return i;
}
}
spin_unlock_irq(&conf->device_lock);
@@ -137,24 +135,6 @@ int multipath_end_request(struct bio *bi
return 0;
}
-/*
- * This routine returns the disk from which the requested read should
- * be done.
- */
-
-static int multipath_read_balance (multipath_conf_t *conf)
-{
- int disk;
-
- for (disk = 0; disk < conf->raid_disks; disk++) {
- mdk_rdev_t *rdev = conf->multipaths[disk].rdev;
- if (rdev && rdev->in_sync)
- return disk;
- }
- BUG();
- return 0;
-}
-
static void unplug_slaves(mddev_t *mddev)
{
multipath_conf_t *conf = mddev_to_conf(mddev);
@@ -204,14 +184,14 @@ static int multipath_make_request (reque
disk_stat_inc(mddev->gendisk, reads);
disk_stat_add(mddev->gendisk, read_sectors, bio_sectors(bio));
}
- /*
- * read balancing logic:
- */
- spin_lock_irq(&conf->device_lock);
- mp_bh->path = multipath_read_balance(conf);
+
+ mp_bh->path = multipath_map(conf);
+ if (mp_bh->path < 0) {
+ bio_endio(bio, bio->bi_size, -EIO);
+ mempool_free(mp_bh, conf->pool);
+ return 0;
+ }
multipath = conf->multipaths + mp_bh->path;
- atomic_inc(&multipath->rdev->nr_pending);
- spin_unlock_irq(&conf->device_lock);
mp_bh->bio = *bio;
mp_bh->bio.bi_bdev = multipath->rdev->bdev;
@@ -400,7 +380,7 @@ static void multipathd (mddev_t *mddev)
struct multipath_bh *mp_bh;
struct bio *bio;
unsigned long flags;
- mdk_rdev_t *rdev;
+ multipath_conf_t *conf = mddev_to_conf(mddev);
md_check_recovery(mddev);
for (;;) {
@@ -416,8 +396,7 @@ static void multipathd (mddev_t *mddev)
bio = &mp_bh->bio;
bio->bi_sector = mp_bh->master_bio->bi_sector;
- rdev = NULL;
- if (multipath_map (mddev, &rdev)<0) {
+ if ((mp_bh->path = multipath_map (conf))<0) {
printk(KERN_ALERT "multipath: %s: unrecoverable IO read"
" error for block %llu\n",
bdevname(bio->bi_bdev,b),
@@ -428,7 +407,7 @@ static void multipathd (mddev_t *mddev)
" to another IO path\n",
bdevname(bio->bi_bdev,b),
(unsigned long long)bio->bi_sector);
- bio->bi_bdev = rdev->bdev;
+ bio->bi_bdev = conf->multipaths[mp_bh->path].rdev->bdev;
generic_make_request(bio);
}
}
-
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