kernel/linux.git/drivers/md/bcache/sysfs.c, branch v5.10.257

bcache: fix variable length array abuse in btree_iter

2024-07-05T07:12:43+00:00

[ Upstream commit 3a861560ccb35f2a4f0a4b8207fa7c2a35fc7f31 ] btree_iter is used in two ways: either allocated on the stack with a fixed size MAX_BSETS, or from a mempool with a dynamic size based on the specific cache set. Previously, the struct had a fixed-length array of size MAX_BSETS which was indexed out-of-bounds for the dynamically-sized iterators, which causes UBSAN to complain. This patch uses the same approach as in bcachefs's sort_iter and splits the iterator into a btree_iter with a flexible array member and a btree_iter_stack which embeds a btree_iter as well as a fixed-length data array. Cc: stable@vger.kernel.org Closes: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/2039368 Signed-off-by: Matthew Mirvish Signed-off-by: Coly Li Link: https://lore.kernel.org/r/20240509011117.2697-3-colyli@suse.de Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin

bcache: prevent potential division by zero error

2023-12-08T07:46:11+00:00

commit 2c7f497ac274a14330208b18f6f734000868ebf9 upstream. In SHOW(), the variable 'n' is of type 'size_t.' While there is a conditional check to verify that 'n' is not equal to zero before executing the 'do_div' macro, concerns arise regarding potential division by zero error in 64-bit environments. The concern arises when 'n' is 64 bits in size, greater than zero, and the lower 32 bits of it are zeros. In such cases, the conditional check passes because 'n' is non-zero, but the 'do_div' macro casts 'n' to 'uint32_t,' effectively truncating it to its lower 32 bits. Consequently, the 'n' value becomes zero. To fix this potential division by zero error and ensure precise division handling, this commit replaces the 'do_div' macro with div64_u64(). div64_u64() is designed to work with 64-bit operands, guaranteeing that division is performed correctly. This change enhances the robustness of the code, ensuring that division operations yield accurate results in all scenarios, eliminating the possibility of division by zero, and improving compatibility across different 64-bit environments. Found by Linux Verification Center (linuxtesting.org) with SVACE. Signed-off-by: Rand Deeb Cc: Signed-off-by: Coly Li Link: https://lore.kernel.org/r/20231120052503.6122-5-colyli@suse.de Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman

bcache: check and set sync status on cache's in-memory super block

2020-10-02T20:25:30+00:00

Currently the cache's sync status is checked and set on cache set's in- memory partial super block. After removing the embedded struct cache_sb from cache set and reference cache's in-memory super block from struct cache_set, the sync status can set and check directly on cache's super block. This patch checks and sets the cache sync status directly on cache's in-memory super block. This is a preparation for later removing embedded struct cache_sb from struct cache_set. Signed-off-by: Coly Li Reviewed-by: Hannes Reinecke Signed-off-by: Jens Axboe

bcache: only use bucket_bytes() on struct cache

2020-10-02T20:25:30+00:00

Because struct cache_set and struct cache both have struct cache_sb, macro bucket_bytes() currently are used on both of them. When removing the embedded struct cache_sb from struct cache_set, this macro won't be used on struct cache_set anymore. This patch unifies all bucket_bytes() usage only on struct cache, this is one of the preparation to remove the embedded struct cache_sb from struct cache_set. Signed-off-by: Coly Li Reviewed-by: Hannes Reinecke Signed-off-by: Jens Axboe

bcache: only use block_bytes() on struct cache

2020-10-02T20:25:30+00:00

Because struct cache_set and struct cache both have struct cache_sb, therefore macro block_bytes() can be used on both of them. When removing the embedded struct cache_sb from struct cache_set, this macro won't be used on struct cache_set anymore. This patch unifies all block_bytes() usage only on struct cache, this is one of the preparation to remove the embedded struct cache_sb from struct cache_set. Signed-off-by: Coly Li Reviewed-by: Hannes Reinecke Signed-off-by: Jens Axboe

bcache: add sysfs file to display feature sets information of cache set

2020-07-25T13:38:21+00:00

The following three sysfs files are created to display according feature set information of bcache: /sys/fs/bcache//internal/feature_compat /sys/fs/bcache//internal/feature_ro_compat /sys/fs/bcache//internal/feature_incompat is added by this patch, to display feature sets information of the cache set. Now only an incompat feature 'large_bucket' added in bcache, the sysfs file content is: [large_bucket] string large_bucket means the running bcache drive supports incompat feature 'large_bucket', the wrapping [] means the 'large_bucket' feature is currently enabled on this cache set. This patch is ready to display compat and ro_compat features, in future once bcache code implements such feature sets, the according feature strings will be displayed in their sysfs files too. Signed-off-by: Coly Li Signed-off-by: Jens Axboe

bcache: Convert pr_ uses to a more typical style

2020-05-27T11:19:36+00:00

Remove the trailing newline from the define of pr_fmt and add newlines to the uses. Miscellanea: o Convert bch_bkey_dump from multiple uses of pr_err to pr_cont as the earlier conversion was inappropriate done causing multiple lines to be emitted where only a single output line was desired o Use vsprintf extension %pV in bch_cache_set_error to avoid multiple line output where only a single line output was desired o Coalesce formats Fixes: 6ae63e3501c4 ("bcache: replace printk() by pr_*() routines") Signed-off-by: Joe Perches Signed-off-by: Coly Li Signed-off-by: Jens Axboe

bcache: Use scnprintf() for avoiding potential buffer overflow

2020-03-22T16:06:57+00:00

Since snprintf() returns the would-be-output size instead of the actual output size, the succeeding calls may go beyond the given buffer limit. Fix it by replacing with scnprintf(). Signed-off-by: Takashi Iwai Signed-off-by: Coly Li Signed-off-by: Jens Axboe

bcache: add readahead cache policy options via sysfs interface

2020-02-01T14:55:39+00:00

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

bcache: add idle_max_writeback_rate sysfs interface

2019-11-13T22:42:50+00:00

For writeback mode, if there is no regular I/O request for a while, the writeback rate will be set to the maximum value (1TB/s for now). This is good for most of the storage workload, but there are still people don't what the maximum writeback rate in I/O idle time. This patch adds a sysfs interface file idle_max_writeback_rate to permit people to disable maximum writeback rate. Then the minimum writeback rate can be advised by writeback_rate_minimum in the bcache device's sysfs interface. Reported-by: Christian Balzer Signed-off-by: Coly Li Signed-off-by: Jens Axboe