Btrfs: add -o discard option

Enable discard by default is not a good idea given the the trim speed
of SSD prototypes we've seen, and the carecteristics for many high-end
arrays.  Turn of discards by default and require the -o discard option
to enable them on.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
This commit is contained in:
Christoph Hellwig 2009-10-14 09:24:59 -04:00 committed by Chris Mason
parent 86df7eb921
commit e244a0aeb6
3 changed files with 10 additions and 1 deletions

View file

@ -1153,6 +1153,7 @@ struct btrfs_root {
#define BTRFS_MOUNT_FLUSHONCOMMIT (1 << 7)
#define BTRFS_MOUNT_SSD_SPREAD (1 << 8)
#define BTRFS_MOUNT_NOSSD (1 << 9)
#define BTRFS_MOUNT_DISCARD (1 << 10)
#define btrfs_clear_opt(o, opt) ((o) &= ~BTRFS_MOUNT_##opt)
#define btrfs_set_opt(o, opt) ((o) |= BTRFS_MOUNT_##opt)

View file

@ -1584,6 +1584,9 @@ static int btrfs_discard_extent(struct btrfs_root *root, u64 bytenr,
u64 map_length = num_bytes;
struct btrfs_multi_bio *multi = NULL;
if (!btrfs_test_opt(root, DISCARD))
return 0;
/* Tell the block device(s) that the sectors can be discarded */
ret = btrfs_map_block(&root->fs_info->mapping_tree, READ,
bytenr, &map_length, &multi, 0);

View file

@ -66,7 +66,8 @@ enum {
Opt_degraded, Opt_subvol, Opt_device, Opt_nodatasum, Opt_nodatacow,
Opt_max_extent, Opt_max_inline, Opt_alloc_start, Opt_nobarrier,
Opt_ssd, Opt_nossd, Opt_ssd_spread, Opt_thread_pool, Opt_noacl,
Opt_compress, Opt_notreelog, Opt_ratio, Opt_flushoncommit, Opt_err,
Opt_compress, Opt_notreelog, Opt_ratio, Opt_flushoncommit,
Opt_discard, Opt_err,
};
static match_table_t tokens = {
@ -88,6 +89,7 @@ static match_table_t tokens = {
{Opt_notreelog, "notreelog"},
{Opt_flushoncommit, "flushoncommit"},
{Opt_ratio, "metadata_ratio=%d"},
{Opt_discard, "discard"},
{Opt_err, NULL},
};
@ -257,6 +259,9 @@ int btrfs_parse_options(struct btrfs_root *root, char *options)
info->metadata_ratio);
}
break;
case Opt_discard:
btrfs_set_opt(info->mount_opt, DISCARD);
break;
default:
break;
}