[Ocfs2-tools-devel] [PATCH] discard unused blocks before mkfs

[Joseph Qi]

On 18/2/27 15:53, Larry Chen wrote:
> From: Larry <lchen at suse.com>
> 
> When using a SSD as a block device, if unused SSD blocks could
> be discarded in advance, performance will be improved.
> 
> This patch uses ioctl interface to release unused blocks on SSD
> layer.
> 
> Signed-off-by: Larry Chen <lchen at suse.com>
> ---
>  mkfs.ocfs2/mkfs.c | 51 +++++++++++++++++++++++++++++++++++++++++++++++++++
>  mkfs.ocfs2/mkfs.h | 10 ++++++++++
>  2 files changed, 61 insertions(+)
> 
> diff --git a/mkfs.ocfs2/mkfs.c b/mkfs.ocfs2/mkfs.c
> index 354b2ee5..2aff6973 100644
> --- a/mkfs.ocfs2/mkfs.c
> +++ b/mkfs.ocfs2/mkfs.c
> @@ -543,6 +543,46 @@ static void finish_normal_format(State *s)
>  	ocfs2_close(fs);
>  }
>  
> +static inline errcode_t discard_blocks(State *s, uint64_t block,
> +		uint64_t count)
> +{
> +	int ret;
Let's not mix use of type errcode_t and int.

> +	uint64_t range[2];
> +
> +	range[0] = (uint64_t)(block) << s->blocksize_bits;
> +	range[1] = (uint64_t)(count) << s->blocksize_bits;
> +
> +	ret = ioctl(s->fd, BLKDISCARD, &range);
> +	return ret;
> +}
> +
> +static int discard_device_blocks(State *s)
> +{
> +	uint64_t blocks = s->volume_size_in_blocks;
> +	uint64_t count = DISCARD_STEP_MB;
> +	uint64_t cur = 0;
> +	int retval = 0;
> +
> +	count *= (1024 * 1024);
> +	count >>= s->blocksize_bits;
> +
> +	while (cur < blocks) {
> +		if (cur + count > blocks)
> +			count = blocks - cur;
> +
> +		retval = discard_blocks(s, cur, count);
> +		if (retval) {
> +			if (!s->quiet && errno != EOPNOTSUPP)
> +				com_err(s->progname, errno,
> +					"While discarding unused blocks...skip\n");
> +			break;
> +		}
> +		cur += count;
> +	}
> +
> +	return retval;
> +}
> +
>  int
>  main(int argc, char **argv)
>  {
> @@ -615,6 +655,10 @@ main(int argc, char **argv)
>  		return 0;
>  	}
>  
> +	if (s->discard_blocks) {
This brace is not necessary.

Thanks,
Joseph

> +		discard_device_blocks(s);
> +	}
> +
>  	clear_both_ends(s);
>  
>  	init_record(s, &superblock_rec, SFI_OTHER, S_IFREG | 0644);
> @@ -889,6 +933,7 @@ get_state(int argc, char **argv)
>  	int no_backup_super = -1;
>  	enum ocfs2_feature_levels level = OCFS2_FEATURE_LEVEL_DEFAULT;
>  	ocfs2_fs_options feature_flags = {0,0,0}, reverse_flags = {0,0,0};
> +	int discard_blocks = 1;
>  
>  	static struct option long_options[] = {
>  		{ "block-size", 1, 0, 'b' },
> @@ -903,6 +948,7 @@ get_state(int argc, char **argv)
>  		{ "force", 0, 0, 'F'},
>  		{ "mount", 1, 0, 'M'},
>  		{ "dry-run", 0, 0, 'n' },
> +		{ "no-discard", 0, 0, 'o'},
>  		{ "no-backup-super", 0, 0, BACKUP_SUPER_OPTION },
>  		{ "fs-feature-level=", 1, 0, FEATURE_LEVEL },
>  		{ "fs-features=", 1, 0, FEATURES_OPTION },
> @@ -1103,6 +1149,10 @@ get_state(int argc, char **argv)
>  			globalhb = 1;
>  			break;
>  
> +		case 'o':
> +			discard_blocks = 0;
> +			break;
> +
>  		default:
>  			usage(progname);
>  			break;
> @@ -1148,6 +1198,7 @@ get_state(int argc, char **argv)
>  	s->quiet         = quiet;
>  	s->force         = force;
>  	s->dry_run       = dry_run;
> +	s->discard_blocks = discard_blocks;
>  
>  	s->prompt        = xtool ? 0 : 1;
>  
> diff --git a/mkfs.ocfs2/mkfs.h b/mkfs.ocfs2/mkfs.h
> index f9ba4dcf..b144341f 100644
> --- a/mkfs.ocfs2/mkfs.h
> +++ b/mkfs.ocfs2/mkfs.h
> @@ -41,6 +41,7 @@
>  #include <inttypes.h>
>  #include <ctype.h>
>  #include <assert.h>
> +#include <sys/ioctl.h>
>  
>  #include <uuid/uuid.h>
>  
> @@ -92,6 +93,14 @@
>  
>  #define MAX_EXTALLOC_RESERVE_PERCENT	5
>  
> +#define DISCARD_STEP_MB         2048
> +
> +#if defined(__linux__) && !defined(BLKDISCARD)
> +#define BLKDISCARD		_IO(0x12,119)
> +#endif
> +
> +
> +
>  enum {
>  	SFI_JOURNAL,
>  	SFI_CLUSTER,
> @@ -193,6 +202,7 @@ struct _State {
>  	int inline_data;
>  	int dx_dirs;
>  	int dry_run;
> +	int discard_blocks;
>  
>  	uint32_t blocksize;
>  	uint32_t blocksize_bits;
>