From: Coly Li colyli@suse.de
commit 5342fd4255021ef0c4ce7be52eea1c4ebda11c63 upstream.
If BCH_FEATURE_INCOMPAT_OBSO_LARGE_BUCKET is set in incompat feature set, it means the cache device is created with obsoleted layout with obso_bucket_site_hi. Now bcache does not support this feature bit, a new BCH_FEATURE_INCOMPAT_LOG_LARGE_BUCKET_SIZE incompat feature bit is added for a better layout to support large bucket size.
For the legacy compatibility purpose, if a cache device created with obsoleted BCH_FEATURE_INCOMPAT_OBSO_LARGE_BUCKET feature bit, all bcache devices attached to this cache set should be set to read-only. Then the dirty data can be written back to backing device before re-create the cache device with BCH_FEATURE_INCOMPAT_LOG_LARGE_BUCKET_SIZE feature bit by the latest bcache-tools.
This patch checks BCH_FEATURE_INCOMPAT_OBSO_LARGE_BUCKET feature bit when running a cache set and attach a bcache device to the cache set. If this bit is set, - When run a cache set, print an error kernel message to indicate all following attached bcache device will be read-only. - When attach a bcache device, print an error kernel message to indicate the attached bcache device will be read-only, and ask users to update to latest bcache-tools.
Such change is only for cache device whose bucket size >= 32MB, this is for the zoned SSD and almost nobody uses such large bucket size at this moment. If you don't explicit set a large bucket size for a zoned SSD, such change is totally transparent to your bcache device.
Fixes: ffa470327572 ("bcache: add bucket_size_hi into struct cache_sb_disk for large bucket") Signed-off-by: Coly Li colyli@suse.de Signed-off-by: Jens Axboe axboe@kernel.dk Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/md/bcache/super.c | 15 +++++++++++++++ 1 file changed, 15 insertions(+)
--- a/drivers/md/bcache/super.c +++ b/drivers/md/bcache/super.c @@ -1341,6 +1341,12 @@ int bch_cached_dev_attach(struct cached_ bcache_device_link(&dc->disk, c, "bdev"); atomic_inc(&c->attached_dev_nr);
+ if (bch_has_feature_obso_large_bucket(&(c->cache->sb))) { + pr_err("The obsoleted large bucket layout is unsupported, set the bcache device into read-only\n"); + pr_err("Please update to the latest bcache-tools to create the cache device\n"); + set_disk_ro(dc->disk.disk, 1); + } + /* Allow the writeback thread to proceed */ up_write(&dc->writeback_lock);
@@ -1564,6 +1570,12 @@ static int flash_dev_run(struct cache_se
bcache_device_link(d, c, "volume");
+ if (bch_has_feature_obso_large_bucket(&c->cache->sb)) { + pr_err("The obsoleted large bucket layout is unsupported, set the bcache device into read-only\n"); + pr_err("Please update to the latest bcache-tools to create the cache device\n"); + set_disk_ro(d->disk, 1); + } + return 0; err: kobject_put(&d->kobj); @@ -2123,6 +2135,9 @@ static int run_cache_set(struct cache_se c->cache->sb.last_mount = (u32)ktime_get_real_seconds(); bcache_write_super(c);
+ if (bch_has_feature_obso_large_bucket(&c->cache->sb)) + pr_err("Detect obsoleted large bucket layout, all attached bcache device will be read-only\n"); + list_for_each_entry_safe(dc, t, &uncached_devices, list) bch_cached_dev_attach(dc, c, NULL);