From 963c555e75b033202dd76cf6325a7b7c83d08d5f Mon Sep 17 00:00:00 2001 From: Guoqing Jiang Date: Fri, 14 Jun 2019 17:10:36 +0800 Subject: [PATCH] md: introduce mddev_create/destroy_wb_pool for the change of member device 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 Signed-off-by: Guoqing Jiang Signed-off-by: Song Liu --- drivers/md/md.c | 65 +++++++++++++++++++++++++++++++++++++++++++++++++ drivers/md/md.h | 2 ++ 2 files changed, 67 insertions(+) diff --git a/drivers/md/md.c b/drivers/md/md.c index 9a9762c83cc8..b43207ab00b2 100644 --- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -37,6 +37,7 @@ */ +#include #include #include #include @@ -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")) { diff --git a/drivers/md/md.h b/drivers/md/md.h index d449d514cff9..10f98200e2f8 100644 --- a/drivers/md/md.h +++ b/drivers/md/md.h @@ -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);