mirror of
https://github.com/torvalds/linux
synced 2024-10-02 09:18:22 +00:00
b16671e8f4
When large bucket feature was added, BCH_FEATURE_INCOMPAT_LARGE_BUCKET
was introduced into the incompat feature set. It used bucket_size_hi
(which was added at the tail of struct cache_sb_disk) to extend current
16bit bucket size to 32bit with existing bucket_size in struct
cache_sb_disk.
This is not a good idea, there are two obvious problems,
- Bucket size is always value power of 2, if store log2(bucket size) in
existing bucket_size of struct cache_sb_disk, it is unnecessary to add
bucket_size_hi.
- Macro csum_set() assumes d[SB_JOURNAL_BUCKETS] is the last member in
struct cache_sb_disk, bucket_size_hi was added after d[] which makes
csum_set calculate an unexpected super block checksum.
To fix the above problems, this patch introduces a new incompat feature
bit BCH_FEATURE_INCOMPAT_LOG_LARGE_BUCKET_SIZE, when this bit is set, it
means bucket_size in struct cache_sb_disk stores the order of power-of-2
bucket size value. When user specifies a bucket size larger than 32768
sectors, BCH_FEATURE_INCOMPAT_LOG_LARGE_BUCKET_SIZE will be set to
incompat feature set, and bucket_size stores log2(bucket size) more
than store the real bucket size value.
The obsoleted BCH_FEATURE_INCOMPAT_LARGE_BUCKET won't be used anymore,
it is renamed to BCH_FEATURE_INCOMPAT_OBSO_LARGE_BUCKET and still only
recognized by kernel driver for legacy compatible purpose. The previous
bucket_size_hi is renmaed to obso_bucket_size_hi in struct cache_sb_disk
and not used in bcache-tools anymore.
For cache device created with BCH_FEATURE_INCOMPAT_LARGE_BUCKET feature,
bcache-tools and kernel driver still recognize the feature string and
display it as "obso_large_bucket".
With this change, the unnecessary extra space extend of bcache on-disk
super block can be avoided, and csum_set() may generate expected check
sum as well.
Fixes: ffa4703275 ("bcache: add bucket_size_hi into struct cache_sb_disk for large bucket")
Signed-off-by: Coly Li <colyli@suse.de>
Cc: stable@vger.kernel.org # 5.9+
Signed-off-by: Jens Axboe <axboe@kernel.dk>
76 lines
1.8 KiB
C
76 lines
1.8 KiB
C
// SPDX-License-Identifier: GPL-2.0
|
|
/*
|
|
* Feature set bits and string conversion.
|
|
* Inspired by ext4's features compat/incompat/ro_compat related code.
|
|
*
|
|
* Copyright 2020 Coly Li <colyli@suse.de>
|
|
*
|
|
*/
|
|
#include <linux/bcache.h>
|
|
#include "bcache.h"
|
|
#include "features.h"
|
|
|
|
struct feature {
|
|
int compat;
|
|
unsigned int mask;
|
|
const char *string;
|
|
};
|
|
|
|
static struct feature feature_list[] = {
|
|
{BCH_FEATURE_INCOMPAT, BCH_FEATURE_INCOMPAT_LOG_LARGE_BUCKET_SIZE,
|
|
"large_bucket"},
|
|
{0, 0, 0 },
|
|
};
|
|
|
|
#define compose_feature_string(type) \
|
|
({ \
|
|
struct feature *f; \
|
|
bool first = true; \
|
|
\
|
|
for (f = &feature_list[0]; f->compat != 0; f++) { \
|
|
if (f->compat != BCH_FEATURE_ ## type) \
|
|
continue; \
|
|
if (BCH_HAS_ ## type ## _FEATURE(&c->cache->sb, f->mask)) { \
|
|
if (first) { \
|
|
out += snprintf(out, buf + size - out, \
|
|
"["); \
|
|
} else { \
|
|
out += snprintf(out, buf + size - out, \
|
|
" ["); \
|
|
} \
|
|
} else if (!first) { \
|
|
out += snprintf(out, buf + size - out, " "); \
|
|
} \
|
|
\
|
|
out += snprintf(out, buf + size - out, "%s", f->string);\
|
|
\
|
|
if (BCH_HAS_ ## type ## _FEATURE(&c->cache->sb, f->mask)) \
|
|
out += snprintf(out, buf + size - out, "]"); \
|
|
\
|
|
first = false; \
|
|
} \
|
|
if (!first) \
|
|
out += snprintf(out, buf + size - out, "\n"); \
|
|
})
|
|
|
|
int bch_print_cache_set_feature_compat(struct cache_set *c, char *buf, int size)
|
|
{
|
|
char *out = buf;
|
|
compose_feature_string(COMPAT);
|
|
return out - buf;
|
|
}
|
|
|
|
int bch_print_cache_set_feature_ro_compat(struct cache_set *c, char *buf, int size)
|
|
{
|
|
char *out = buf;
|
|
compose_feature_string(RO_COMPAT);
|
|
return out - buf;
|
|
}
|
|
|
|
int bch_print_cache_set_feature_incompat(struct cache_set *c, char *buf, int size)
|
|
{
|
|
char *out = buf;
|
|
compose_feature_string(INCOMPAT);
|
|
return out - buf;
|
|
}
|