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

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 input overflow to writeback_rate_minimum

2019-11-06T12:05:20+00:00

[ Upstream commit dab71b2db98dcdd4657d151b01a7be88ce10f9d1 ] dc->writeback_rate_minimum is type unsigned integer variable, it is set via sysfs interface, and converte from input string to unsigned integer by d_strtoul_nonzero(). When the converted input value is larger than UINT_MAX, overflow to unsigned integer happens. This patch fixes the overflow by using sysfs_strotoul_clamp() to convert input string and limit the value in range [1, UINT_MAX], then the overflow can be avoided. Signed-off-by: Coly Li Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin

bcache: fix mistaken sysfs entry for io_error counter

2019-07-26T07:14:21+00:00

commit 5461999848e0462c14f306a62923d22de820a59c upstream. In bch_cached_dev_files[] from driver/md/bcache/sysfs.c, sysfs_errors is incorrectly inserted in. The correct entry should be sysfs_io_errors. This patch fixes the problem and now I/O errors of cached device can be read from /sys/block/bcache/bcache/io_errors. Fixes: c7b7bd07404c5 ("bcache: add io_disable to struct cached_dev") Signed-off-by: Coly Li Cc: stable@vger.kernel.org Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman

bcache: only set BCACHE_DEV_WB_RUNNING when cached device attached

2019-06-19T06:18:00+00:00

commit 1f0ffa67349c56ea54c03ccfd1e073c990e7411e upstream. When people set a writeback percent via sysfs file, /sys/block/bcache/bcache/writeback_percent current code directly sets BCACHE_DEV_WB_RUNNING to dc->disk.flags and schedules kworker dc->writeback_rate_update. If there is no cache set attached to, the writeback kernel thread is not running indeed, running dc->writeback_rate_update does not make sense and may cause NULL pointer deference when reference cache set pointer inside update_writeback_rate(). This patch checks whether the cache set point (dc->disk.c) is NULL in sysfs interface handler, and only set BCACHE_DEV_WB_RUNNING and schedule dc->writeback_rate_update when dc->disk.c is not NULL (it means the cache device is attached to a cache set). This problem might be introduced from initial bcache commit, but commit 3fd47bfe55b0 ("bcache: stop dc->writeback_rate_update properly") changes part of the original code piece, so I add 'Fixes: 3fd47bfe55b0' to indicate from which commit this patch can be applied. Fixes: 3fd47bfe55b0 ("bcache: stop dc->writeback_rate_update properly") Reported-by: Bjørn Forsman Signed-off-by: Coly Li Reviewed-by: Bjørn Forsman Cc: stable@vger.kernel.org Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman

bcache: fix potential div-zero error of writeback_rate_p_term_inverse

2019-04-05T20:33:17+00:00

[ Upstream commit 5b5fd3c94eef69dcfaa8648198e54c92e5687d6d ] Current code already uses d_strtoul_nonzero() to convert input string to an unsigned integer, to make sure writeback_rate_p_term_inverse won't be zero value. But overflow may happen when converting input string to an unsigned integer value by d_strtoul_nonzero(), then dc->writeback_rate_p_term_inverse can still be set to 0 even if the sysfs file input value is not zero, e.g. 4294967296 (a.k.a UINT_MAX+1). If dc->writeback_rate_p_term_inverse is set to 0, it might cause a dev-zero error in following code from __update_writeback_rate(), int64_t proportional_scaled = div_s64(error, dc->writeback_rate_p_term_inverse); This patch replaces d_strtoul_nonzero() by sysfs_strtoul_clamp() and limit the value range in [1, UINT_MAX]. Then the unsigned integer overflow and dev-zero error can be avoided. Signed-off-by: Coly Li Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin

bcache: fix potential div-zero error of writeback_rate_i_term_inverse

2019-04-05T20:33:09+00:00

[ Upstream commit c3b75a2199cdbfc1c335155fe143d842604b1baa ] dc->writeback_rate_i_term_inverse can be set via sysfs interface. It is in type unsigned int, and convert from input string by d_strtoul(). The problem is d_strtoul() does not check valid range of the input, if 4294967296 is written into sysfs file writeback_rate_i_term_inverse, an overflow of unsigned integer will happen and value 0 is set to dc->writeback_rate_i_term_inverse. In writeback.c:__update_writeback_rate(), there are following lines of code, integral_scaled = div_s64(dc->writeback_rate_integral, dc->writeback_rate_i_term_inverse); If dc->writeback_rate_i_term_inverse is set to 0 via sysfs interface, a div-zero error might be triggered in the above code. Therefore we need to add a range limitation in the sysfs interface, this is what this patch does, use sysfs_stroul_clamp() to replace d_strtoul() and restrict the input range in [1, UINT_MAX]. Signed-off-by: Coly Li Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin

bcache: fix input overflow to sequential_cutoff

2019-04-05T20:33:09+00:00

[ Upstream commit 8c27a3953e92eb0b22dbb03d599f543a05f9574e ] People may set sequential_cutoff of a cached device via sysfs file, but current code does not check input value overflow. E.g. if value 4294967295 (UINT_MAX) is written to file sequential_cutoff, its value is 4GB, but if 4294967296 (UINT_MAX + 1) is written into, its value will be 0. This is an unexpected behavior. This patch replaces d_strtoi_h() by sysfs_strtoul_clamp() to convert input string to unsigned integer value, and limit its range in [0, UINT_MAX]. Then the input overflow can be fixed. Signed-off-by: Coly Li Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin

bcache: fix input overflow to cache set sysfs file io_error_halflife

2019-04-05T20:33:09+00:00

[ Upstream commit a91fbda49f746119828f7e8ad0f0aa2ab0578f65 ] Cache set sysfs entry io_error_halflife is used to set c->error_decay. c->error_decay is in type unsigned int, and it is converted by strtoul_or_return(), therefore overflow to c->error_decay is possible for a large input value. This patch fixes the overflow by using strtoul_safe_clamp() to convert input string to an unsigned long value in range [0, UINT_MAX], then divides by 88 and set it to c->error_decay. Signed-off-by: Coly Li Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin

bcache: Populate writeback_rate_minimum attribute

2018-11-13T19:08:22+00:00

[ Upstream commit 7567c2a2ad9e80a2ce977eef535e64b61899633e ] Forgot to include the maintainers with my first email. Somewhere between Michael Lyle's original "bcache: PI controller for writeback rate V2" patch dated 07 Sep 2017 and 1d316e6 bcache: implement PI controller for writeback rate, the mapping of the writeback_rate_minimum attribute was dropped. Re-add the missing sysfs writeback_rate_minimum attribute mapping to "allow the user to specify a minimum rate at which dirty blocks are retired." Fixes: 1d316e6 ("bcache: implement PI controller for writeback rate") Signed-off-by: Ben Peddell Signed-off-by: Coly Li Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

bcache: add static const prefix to char * array declarations

2018-08-11T21:46:42+00:00

This patch declares char * array with const prefix in sysfs.c, which is suggested by checkpatch.pl. Signed-off-by: Coly Li Reviewed-by: Shenghui Wang Signed-off-by: Jens Axboe