kernel/linux.git/drivers/md/bcache, branch v4.19.112

bcache: explicity type cast in bset_bkey_last()

2020-02-24T07:34:53+00:00

[ Upstream commit 7c02b0055f774ed9afb6e1c7724f33bf148ffdc0 ] In bset.h, macro bset_bkey_last() is defined as, bkey_idx((struct bkey *) (i)->d, (i)->keys) Parameter i can be variable type of data structure, the macro always works once the type of struct i has member 'd' and 'keys'. bset_bkey_last() is also used in macro csum_set() to calculate the checksum of a on-disk data structure. When csum_set() is used to calculate checksum of on-disk bcache super block, the parameter 'i' data type is struct cache_sb_disk. Inside struct cache_sb_disk (also in struct cache_sb) the member keys is __u16 type. But bkey_idx() expects unsigned int (a 32bit width), so there is problem when sending parameters via stack to call bkey_idx(). Sparse tool from Intel 0day kbuild system reports this incompatible problem. bkey_idx() is part of user space API, so the simplest fix is to cast the (i)->keys to unsigned int type in macro bset_bkey_last(). Reported-by: kbuild test robot Signed-off-by: Coly Li Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin

bcache: cached_dev_free needs to put the sb page

2020-02-24T07:34:51+00:00

[ Upstream commit e8547d42095e58bee658f00fef8e33d2a185c927 ] Same as cache device, the buffer page needs to be put while freeing cached_dev. Otherwise a page would be leaked every time a cached_dev is stopped. Signed-off-by: Liang Chen Signed-off-by: Christoph Hellwig Signed-off-by: Coly Li Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin

bcache: add readahead cache policy options via sysfs interface

2020-02-11T12:34:08+00:00

commit 038ba8cc1bffc51250add4a9b9249d4331576d8f upstream. In year 2007 high performance SSD was still expensive, in order to save more space for real workload or meta data, the readahead I/Os for non-meta data was bypassed and not cached on SSD. In now days, SSD price drops a lot and people can find larger size SSD with more comfortable price. It is unncessary to alway bypass normal readahead I/Os to save SSD space for now. This patch adds options for readahead data cache policies via sysfs file /sys/block/bcache/readahead_cache_policy, the options are, - "all": cache all readahead data I/Os. - "meta-only": only cache meta data, and bypass other regular I/Os. If users want to make bcache continue to only cache readahead request for metadata and bypass regular data readahead, please set "meta-only" to this sysfs file. By default, bcache will back to cache all read- ahead requests now. Cc: stable@vger.kernel.org Signed-off-by: Coly Li Acked-by: Eric Wheeler Cc: Michael Lyle Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman

bcache: Fix an error code in bch_dump_read()

2020-01-27T13:51:09+00:00

[ Upstream commit d66c9920c0cf984cf99cab5036fd5f3a1b7fba46 ] The copy_to_user() function returns the number of bytes remaining to be copied, but the intention here was to return -EFAULT if the copy fails. Fixes: cafe56359144 ("bcache: A block layer cache") Signed-off-by: Dan Carpenter Signed-off-by: Coly Li Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin

bcache: at least try to shrink 1 node in bch_mca_scan()

2020-01-04T18:12:58+00:00

[ Upstream commit 9fcc34b1a6dd4b8e5337e2b6ef45e428897eca6b ] In bch_mca_scan(), the number of shrinking btree node is calculated by code like this, unsigned long nr = sc->nr_to_scan; nr /= c->btree_pages; nr = min_t(unsigned long, nr, mca_can_free(c)); variable sc->nr_to_scan is number of objects (here is bcache B+tree nodes' number) to shrink, and pointer variable sc is sent from memory management code as parametr of a callback. If sc->nr_to_scan is smaller than c->btree_pages, after the above calculation, variable 'nr' will be 0 and nothing will be shrunk. It is frequeently observed that only 1 or 2 is set to sc->nr_to_scan and make nr to be zero. Then bch_mca_scan() will do nothing more then acquiring and releasing mutex c->bucket_lock. This patch checkes whether nr is 0 after the above calculation, if 0 is the result then set 1 to variable 'n'. Then at least bch_mca_scan() will try to shrink a single B+tree node. Signed-off-by: Coly Li Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin

bcache: fix deadlock in bcache_allocator

2019-12-31T15:36:02+00:00

[ Upstream commit 84c529aea182939e68f618ed9813740c9165c7eb ] bcache_allocator can call the following: bch_allocator_thread() -> bch_prio_write() -> bch_bucket_alloc() -> wait on &ca->set->bucket_wait But the wake up event on bucket_wait is supposed to come from bch_allocator_thread() itself => deadlock: [ 1158.490744] INFO: task bcache_allocato:15861 blocked for more than 10 seconds. [ 1158.495929] Not tainted 5.3.0-050300rc3-generic #201908042232 [ 1158.500653] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [ 1158.504413] bcache_allocato D 0 15861 2 0x80004000 [ 1158.504419] Call Trace: [ 1158.504429] __schedule+0x2a8/0x670 [ 1158.504432] schedule+0x2d/0x90 [ 1158.504448] bch_bucket_alloc+0xe5/0x370 [bcache] [ 1158.504453] ? wait_woken+0x80/0x80 [ 1158.504466] bch_prio_write+0x1dc/0x390 [bcache] [ 1158.504476] bch_allocator_thread+0x233/0x490 [bcache] [ 1158.504491] kthread+0x121/0x140 [ 1158.504503] ? invalidate_buckets+0x890/0x890 [bcache] [ 1158.504506] ? kthread_park+0xb0/0xb0 [ 1158.504510] ret_from_fork+0x35/0x40 Fix by making the call to bch_prio_write() non-blocking, so that bch_allocator_thread() never waits on itself. Moreover, make sure to wake up the garbage collector thread when bch_prio_write() is failing to allocate buckets. BugLink: https://bugs.launchpad.net/bugs/1784665 BugLink: https://bugs.launchpad.net/bugs/1796292 Signed-off-by: Andrea Righi Signed-off-by: Coly Li Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin

bcache: fix static checker warning in bcache_device_free()

2019-12-31T15:36:01+00:00

[ Upstream commit 2d8869518a525c9bce5f5268419df9dfbe3dfdeb ] Commit cafe56359144 ("bcache: A block layer cache") leads to the following static checker warning: ./drivers/md/bcache/super.c:770 bcache_device_free() warn: variable dereferenced before check 'd->disk' (see line 766) drivers/md/bcache/super.c 762 static void bcache_device_free(struct bcache_device *d) 763 { 764 lockdep_assert_held(&bch_register_lock); 765 766 pr_info("%s stopped", d->disk->disk_name); ^^^^^^^^^ Unchecked dereference. 767 768 if (d->c) 769 bcache_device_detach(d); 770 if (d->disk && d->disk->flags & GENHD_FL_UP) ^^^^^^^ Check too late. 771 del_gendisk(d->disk); 772 if (d->disk && d->disk->queue) 773 blk_cleanup_queue(d->disk->queue); 774 if (d->disk) { 775 ida_simple_remove(&bcache_device_idx, 776 first_minor_to_idx(d->disk->first_minor)); 777 put_disk(d->disk); 778 } 779 It is not 100% sure that the gendisk struct of bcache device will always be there, the warning makes sense when there is problem in block core. This patch tries to remove the static checking warning by checking d->disk to avoid NULL pointer deferences. Reported-by: Dan Carpenter Signed-off-by: Coly Li Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin

bcache: do not mark writeback_running too early

2019-12-05T08:20:07+00:00

[ Upstream commit 79b791466e525c98f6aeee9acf5726e7b27f4231 ] A fresh backing device is not attached to any cache_set, and has no writeback kthread created until first attached to some cache_set. But bch_cached_dev_writeback_init run " dc->writeback_running = true; WARN_ON(test_and_clear_bit(BCACHE_DEV_WB_RUNNING, &dc->disk.flags)); " for any newly formatted backing devices. For a fresh standalone backing device, we can get something like following even if no writeback kthread created: ------------------------ /sys/block/bcache0/bcache# cat writeback_running 1 /sys/block/bcache0/bcache# cat writeback_rate_debug rate: 512.0k/sec dirty: 0.0k target: 0.0k proportional: 0.0k integral: 0.0k change: 0.0k/sec next io: -15427384ms The none ZERO fields are misleading as no alive writeback kthread yet. Set dc->writeback_running false as no writeback thread created in bch_cached_dev_writeback_init(). We have writeback thread created and woken up in bch_cached_dev_writeback _start(). Set dc->writeback_running true before bch_writeback_queue() called, as a writeback thread will check if dc->writeback_running is true before writing back dirty data, and hung if false detected. After the change, we can get the following output for a fresh standalone backing device: ----------------------- /sys/block/bcache0/bcache$ cat writeback_running 0 /sys/block/bcache0/bcache# cat writeback_rate_debug rate: 0.0k/sec dirty: 0.0k target: 0.0k proportional: 0.0k integral: 0.0k change: 0.0k/sec next io: 0ms v1 -> v2: Set dc->writeback_running before bch_writeback_queue() called, Signed-off-by: Shenghui Wang Signed-off-by: Coly Li Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin

bcache: do not check if debug dentry is ERR or NULL explicitly on remove

2019-12-05T08:20:07+00:00

[ Upstream commit ae17102316550b4b230a283febe31b2a9ff30084 ] debugfs_remove and debugfs_remove_recursive will check if the dentry pointer is NULL or ERR, and will do nothing in that case. Remove the check in cache_set_free and bch_debug_init. Signed-off-by: Shenghui Wang Signed-off-by: Coly Li Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin

bcache: recal cached_dev_sectors on detach

2019-11-24T07:20:38+00:00

[ Upstream commit 46010141da6677b81cc77f9b47f8ac62bd1cbfd3 ] Recal cached_dev_sectors on cached_dev detached, as recal done on cached_dev attached. Update the cached_dev_sectors before bcache_device_detach called as bcache_device_detach will set bcache_device->c to NULL. Signed-off-by: Shenghui Wang Signed-off-by: Coly Li Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin