From a33df2d2ef038dca4171e06a501e4d0ffc9072cc Mon Sep 17 00:00:00 2001 Message-Id: In-Reply-To: References: From: Ryan Harper Date: Tue, 5 Dec 2017 22:50:15 +0000 Subject: [PATCH] bcache: decouple emitting a cached_dev CHANGE uevent - decouple emitting a cached_dev CHANGE uevent which includes dev.uuid and dev.label from bch_cached_dev_run() which only happens when a bcacheX device is bound to the actual backing block device (bcache0 -> vdb) - update bch_cached_dev_run() to invoke bch_cached_dev_emit_change() as needed; no functional code path changes here - Modify register_bcache to detect a re-registering of a bcache cached_dev, and in that case call bcache_cached_dev_emit_change() to emit the uevent needed to trigger SYMLINK generation Signed-off-by: Joseph Salisbury --- drivers/md/bcache/bcache.h | 1 + drivers/md/bcache/super.c | 53 +++++++++++++++++++++++++++++++++++++--------- 2 files changed, 44 insertions(+), 10 deletions(-) diff --git a/drivers/md/bcache/bcache.h b/drivers/md/bcache/bcache.h index 2ed9bd2..f646a1d 100644 --- a/drivers/md/bcache/bcache.h +++ b/drivers/md/bcache/bcache.h @@ -907,6 +907,7 @@ int bch_flash_dev_create(struct cache_set *c, uint64_t size); int bch_cached_dev_attach(struct cached_dev *, struct cache_set *); void bch_cached_dev_detach(struct cached_dev *); +void bch_cached_dev_emit_change(struct cached_dev *); void bch_cached_dev_run(struct cached_dev *); void bcache_device_stop(struct bcache_device *); diff --git a/drivers/md/bcache/super.c b/drivers/md/bcache/super.c index 0a68af8..cf8d587 100644 --- a/drivers/md/bcache/super.c +++ b/drivers/md/bcache/super.c @@ -838,7 +838,7 @@ static void calc_cached_dev_sectors(struct cache_set *c) c->cached_dev_sectors = sectors; } -void bch_cached_dev_run(struct cached_dev *dc) +void bch_cached_dev_emit_change(struct cached_dev *dc) { struct bcache_device *d = &dc->disk; char buf[SB_LABEL_SIZE + 1]; @@ -853,9 +853,18 @@ void bch_cached_dev_run(struct cached_dev *dc) buf[SB_LABEL_SIZE] = '\0'; env[2] = kasprintf(GFP_KERNEL, "CACHED_LABEL=%s", buf); + /* won't show up in the uevent file, use udevadm monitor -e instead + * only class / kset properties are persistent */ + kobject_uevent_env(&disk_to_dev(d->disk)->kobj, KOBJ_CHANGE, env); + kfree(env[1]); + kfree(env[2]); + +} + +void bch_cached_dev_run(struct cached_dev *dc) +{ + struct bcache_device *d = &dc->disk; if (atomic_xchg(&dc->running, 1)) { - kfree(env[1]); - kfree(env[2]); return; } @@ -871,11 +880,9 @@ void bch_cached_dev_run(struct cached_dev *dc) add_disk(d->disk); bd_link_disk_holder(dc->bdev, dc->disk.disk); - /* won't show up in the uevent file, use udevadm monitor -e instead - * only class / kset properties are persistent */ - kobject_uevent_env(&disk_to_dev(d->disk)->kobj, KOBJ_CHANGE, env); - kfree(env[1]); - kfree(env[2]); + + /* emit change event */ + bch_cached_dev_emit_change(dc); if (sysfs_create_link(&d->kobj, &disk_to_dev(d->disk)->kobj, "dev") || sysfs_create_link(&disk_to_dev(d->disk)->kobj, &d->kobj, "bcache")) @@ -1922,6 +1929,21 @@ static bool bch_is_open_backing(struct block_device *bdev) { return false; } +static struct cached_dev *bch_find_cached_dev(struct block_device *bdev) { + struct cache_set *c, *tc; + struct cached_dev *dc, *t; + + list_for_each_entry_safe(c, tc, &bch_cache_sets, list) + list_for_each_entry_safe(dc, t, &c->cached_devs, list) + if (dc->bdev == bdev) + return dc; + list_for_each_entry_safe(dc, t, &uncached_devices, list) + if (dc->bdev == bdev) + return dc; + + return NULL; +} + static bool bch_is_open_cache(struct block_device *bdev) { struct cache_set *c, *tc; struct cache *ca; @@ -1947,6 +1969,7 @@ static ssize_t register_bcache(struct kobject *k, struct kobj_attribute *attr, struct cache_sb *sb = NULL; struct block_device *bdev = NULL; struct page *sb_page = NULL; + struct cached_dev *dc = NULL; if (!try_module_get(THIS_MODULE)) return -EBUSY; @@ -1963,10 +1986,20 @@ static ssize_t register_bcache(struct kobject *k, struct kobj_attribute *attr, if (bdev == ERR_PTR(-EBUSY)) { bdev = lookup_bdev(strim(path), 0); mutex_lock(&bch_register_lock); - if (!IS_ERR(bdev) && bch_is_open(bdev)) + if (!IS_ERR(bdev) && bch_is_open(bdev)) { err = "device already registered"; - else + /* emit CHANGE event for backing devices to export + * CACHED_{UUID/LABEL} values to udev */ + if (bch_is_open_backing(bdev)) { + dc = bch_find_cached_dev(bdev); + if (dc) { + bch_cached_dev_emit_change(dc); + err = "device already registered (emitting change event)"; + } + } + } else { err = "device busy"; + } mutex_unlock(&bch_register_lock); if (!IS_ERR(bdev)) bdput(bdev); -- 2.7.4