Commit 092bd54d authored by Coly Li's avatar Coly Li Committed by Jens Axboe
Browse files

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



The following three sysfs files are created to display according feature
set information of bcache:
	/sys/fs/bcache/<cache set UUID>/internal/feature_compat
	/sys/fs/bcache/<cache set UUID>/internal/feature_ro_compat
	/sys/fs/bcache/<cache set UUID>/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: default avatarColy Li <colyli@suse.de>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent ffa47032

drivers/md/bcache/Makefile

+1 −1
Original line number Diff line number Diff line
@@ -4,4 +4,4 @@ obj-$(CONFIG_BCACHE) += bcache.o 


bcache-y		:= alloc.o bset.o btree.o closure.o debug.o extents.o\

	io.o journal.o movinggc.o request.o stats.o super.o sysfs.o trace.o\

	util.o writeback.o
 
	util.o writeback.o features.o

drivers/md/bcache/features.c

+53 −0
Original line number Diff line number Diff line
@@ -8,6 +8,7 @@ 
 */

#include <linux/bcache.h>

#include "bcache.h"

#include "features.h"



struct feature {

	int		compat;
@@ -20,3 +21,55 @@ static struct feature feature_list[] = { 
		"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->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->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;

}

drivers/md/bcache/features.h

+5 −0
Original line number Diff line number Diff line
@@ -78,4 +78,9 @@ static inline void bch_clear_feature_##name(struct cache_sb *sb) \ 
}



BCH_FEATURE_INCOMPAT_FUNCS(large_bucket, LARGE_BUCKET);



int bch_print_cache_set_feature_compat(struct cache_set *c, char *buf, int size);

int bch_print_cache_set_feature_ro_compat(struct cache_set *c, char *buf, int size);

int bch_print_cache_set_feature_incompat(struct cache_set *c, char *buf, int size);



#endif

drivers/md/bcache/sysfs.c

+14 −0
Original line number Diff line number Diff line
@@ -11,6 +11,7 @@ 
#include "btree.h"

#include "request.h"

#include "writeback.h"

#include "features.h"



#include <linux/blkdev.h>

#include <linux/sort.h>
@@ -88,6 +89,9 @@ read_attribute(btree_used_percent); 
read_attribute(average_key_size);

read_attribute(dirty_data);

read_attribute(bset_tree_stats);

read_attribute(feature_compat);

read_attribute(feature_ro_compat);

read_attribute(feature_incompat);



read_attribute(state);

read_attribute(cache_read_races);
@@ -779,6 +783,13 @@ SHOW(__bch_cache_set) 
	if (attr == &sysfs_bset_tree_stats)

		return bch_bset_print_stats(c, buf);



	if (attr == &sysfs_feature_compat)

		return bch_print_cache_set_feature_compat(c, buf, PAGE_SIZE);

	if (attr == &sysfs_feature_ro_compat)

		return bch_print_cache_set_feature_ro_compat(c, buf, PAGE_SIZE);

	if (attr == &sysfs_feature_incompat)

		return bch_print_cache_set_feature_incompat(c, buf, PAGE_SIZE);



	return 0;

}

SHOW_LOCKED(bch_cache_set)
@@ -987,6 +998,9 @@ static struct attribute *bch_cache_set_internal_files[] = { 
	&sysfs_io_disable,

	&sysfs_cutoff_writeback,

	&sysfs_cutoff_writeback_sync,

	&sysfs_feature_compat,

	&sysfs_feature_ro_compat,

	&sysfs_feature_incompat,

	NULL

};

KTYPE(bch_cache_set_internal);

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