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md: introduce mddev_create/destroy_wb_pool for the change of member device

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Previously, we called rdev_init_wb to avoid potential data
inconsistency when array is created.

Now, we need to call the function and create mempool if a
device is added or just be flaged as "writemostly". So
mddev_create_wb_pool is introduced and called accordingly.
And for safety reason, we mark implicit GFP_NOIO allocation
scope for create mempool during mddev_suspend/mddev_resume.

And mempool should be removed conversely after remove a
member device or its's "writemostly" flag, which is done
by call mddev_destroy_wb_pool.

Reviewed-by: NeilBrown <neilb@suse.com>
Signed-off-by: Guoqing Jiang <gqjiang@suse.com>
Signed-off-by: Song Liu <songliubraving@fb.com>
This commit is contained in:
Guoqing Jiang 2019-06-14 17:10:36 +08:00 committed by Song Liu
parent 3e148a3209
commit 963c555e75
2 changed files with 67 additions and 0 deletions
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65
drivers/md/md.c
View File

@ -37,6 +37,7 @@
*/
#include <linux/sched/mm.h>
#include <linux/sched/signal.h>
#include <linux/kthread.h>
#include <linux/blkdev.h>
@ -137,6 +138,64 @@ static int rdev_init_wb(struct md_rdev *rdev)
return 1;
}
/*
* Create wb_info_pool if rdev is the first multi-queue device flaged
* with writemostly, also write-behind mode is enabled.
*/
void mddev_create_wb_pool(struct mddev *mddev, struct md_rdev *rdev,
bool is_suspend)
{
if (mddev->bitmap_info.max_write_behind == 0)
return;
if (!test_bit(WriteMostly, &rdev->flags) || !rdev_init_wb(rdev))
return;
if (mddev->wb_info_pool == NULL) {
unsigned int noio_flag;
if (!is_suspend)
mddev_suspend(mddev);
noio_flag = memalloc_noio_save();
mddev->wb_info_pool = mempool_create_kmalloc_pool(NR_WB_INFOS,
sizeof(struct wb_info));
memalloc_noio_restore(noio_flag);
if (!mddev->wb_info_pool)
pr_err("can't alloc memory pool for writemostly\n");
if (!is_suspend)
mddev_resume(mddev);
}
}
EXPORT_SYMBOL_GPL(mddev_create_wb_pool);
/*
* destroy wb_info_pool if rdev is the last device flaged with WBCollisionCheck.
*/
static void mddev_destroy_wb_pool(struct mddev *mddev, struct md_rdev *rdev)
{
if (!test_and_clear_bit(WBCollisionCheck, &rdev->flags))
return;
if (mddev->wb_info_pool) {
struct md_rdev *temp;
int num = 0;
/*
* Check if other rdevs need wb_info_pool.
*/
rdev_for_each(temp, mddev)
if (temp != rdev &&
test_bit(WBCollisionCheck, &temp->flags))
num++;
if (!num) {
mddev_suspend(rdev->mddev);
mempool_destroy(mddev->wb_info_pool);
mddev->wb_info_pool = NULL;
mddev_resume(rdev->mddev);
}
}
}
static struct ctl_table_header *raid_table_header;
static struct ctl_table raid_table[] = {
@ -2223,6 +2282,9 @@ static int bind_rdev_to_array(struct md_rdev *rdev, struct mddev *mddev)
rdev->mddev = mddev;
pr_debug("md: bind<%s>\n", b);
if (mddev->raid_disks)
mddev_create_wb_pool(mddev, rdev, false);
if ((err = kobject_add(&rdev->kobj, &mddev->kobj, "dev-%s", b)))
goto fail;
@ -2259,6 +2321,7 @@ static void unbind_rdev_from_array(struct md_rdev *rdev)
bd_unlink_disk_holder(rdev->bdev, rdev->mddev->gendisk);
list_del_rcu(&rdev->same_set);
pr_debug("md: unbind<%s>\n", bdevname(rdev->bdev,b));
mddev_destroy_wb_pool(rdev->mddev, rdev);
rdev->mddev = NULL;
sysfs_remove_link(&rdev->kobj, "block");
sysfs_put(rdev->sysfs_state);
@ -2771,8 +2834,10 @@ state_store(struct md_rdev *rdev, const char *buf, size_t len)
}
} else if (cmd_match(buf, "writemostly")) {
set_bit(WriteMostly, &rdev->flags);
mddev_create_wb_pool(rdev->mddev, rdev, false);
err = 0;
} else if (cmd_match(buf, "-writemostly")) {
mddev_destroy_wb_pool(rdev->mddev, rdev);
clear_bit(WriteMostly, &rdev->flags);
err = 0;
} else if (cmd_match(buf, "blocked")) {

2
drivers/md/md.h
View File

@ -730,6 +730,8 @@ extern struct bio *bio_alloc_mddev(gfp_t gfp_mask, int nr_iovecs,
extern void md_reload_sb(struct mddev *mddev, int raid_disk);
extern void md_update_sb(struct mddev *mddev, int force);
extern void md_kick_rdev_from_array(struct md_rdev * rdev);
extern void mddev_create_wb_pool(struct mddev *mddev, struct md_rdev *rdev,
bool is_suspend);
struct md_rdev *md_find_rdev_nr_rcu(struct mddev *mddev, int nr);
struct md_rdev *md_find_rdev_rcu(struct mddev *mddev, dev_t dev);