Hi maintainers and folks, This patch set tries to improve cache device failure handling. A basic idea to handle failed cache device is, - Unregister cache set - Detach all backing devices attached to this cache set - Stop all bcache devices linked to this cache set The above process is named 'cache set retire' by me. The result of cache set retire is, cache set and bcache devices are all removed, following I/O requests will get failed immediately to notift upper layer or user space coce that the cache device is failed or disconnected. The first 8 patches of this patch set is to fix existing bugs in bcache, the last 2 patches do the real improvement. Order of applying these patches is important, if the last 2 patches are applied firstly, kernel panic or process hang will be observed. Therefore I suggest to apply the first 8 fixes, then apply the last 2 patches. The patch set is tested with writethrough, writeback, writearound mode, read/write/readwrite workloads, so far it works as expected. IMHO the cache set retire logic is complicated, I need your help to review the patches, any question is warmly wlecome. Coly Li (10): bcache: exit bch_writeback_thread() with proper task state bcache: set task properly in allocator_wait() bcache: reduce cache_set devices iteration by devices_max_used bcache: fix cached_dev->count usage for bch_cache_set_error() bcache: stop dc->writeback_rate_update if cache set is stopping bcache: stop dc->writeback_rate_update, dc->writeback_thread earlier bcache: set error_limit correctly bcache: fix misleading error message in bch_count_io_errors() bcache: add io_disable to struct cache_set bcache: stop all attached bcache devices for a retired cache set drivers/md/bcache/alloc.c | 5 ++--- drivers/md/bcache/bcache.h | 19 +++++++++++++++- drivers/md/bcache/btree.c | 8 ++++--- drivers/md/bcache/io.c | 15 ++++++++----- drivers/md/bcache/journal.c | 4 ++-- drivers/md/bcache/request.c | 26 ++++++++++++++++------ drivers/md/bcache/super.c | 51 +++++++++++++++++++++++++++++++++++-------- drivers/md/bcache/sysfs.c | 8 +++++-- drivers/md/bcache/util.h | 6 ----- drivers/md/bcache/writeback.c | 51 +++++++++++++++++++++++++++++++++---------- drivers/md/bcache/writeback.h | 4 +--- 11 files changed, 144 insertions(+), 53 deletions(-) Thanks in advance. Coly Li
