From 7e64db1597fe114b83fe17d0ba96c6aa5fca419a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jan=20H=C3=B6ppner?= <hoeppner@linux.ibm.com>
Date: Fri, 27 Apr 2018 16:57:44 +0200
Subject: [PATCH] s390/dasd: Add discard support for ESE volumes
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
ESE (Extent Space Efficient) volumes are thin-provisioned and therefore
space is only occupied with real data. In order to make previously used
space available for re-allocation again, discard support is enabled for
ESE volumes allowing the DASD driver to release said space.
Signed-off-by: Jan Höppner <hoeppner@linux.ibm.com>
Reviewed-by: Stefan Haberland <sth@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
---
drivers/s390/block/dasd_eckd.c | 57 ++++++++++++++++++++++++++++++++--
1 file changed, 54 insertions(+), 3 deletions(-)
diff --git a/drivers/s390/block/dasd_eckd.c b/drivers/s390/block/dasd_eckd.c
index 3edb35359843e..7f7429a99a671 100644
--- a/drivers/s390/block/dasd_eckd.c
+++ b/drivers/s390/block/dasd_eckd.c
@@ -1987,6 +1987,9 @@ dasd_eckd_check_characteristics(struct dasd_device *device)
if (readonly)
set_bit(DASD_FLAG_DEVICE_RO, &device->flags);
+ if (dasd_eckd_is_ese(device))
+ dasd_set_feature(device->cdev, DASD_FEATURE_DISCARD, 1);
+
dev_info(&device->cdev->dev, "New DASD %04X/%02X (CU %04X/%02X) "
"with %d cylinders, %d heads, %d sectors%s\n",
private->rdc_data.dev_type,
@@ -3617,6 +3620,14 @@ static int dasd_eckd_release_space(struct dasd_device *device,
return -EINVAL;
}
+static struct dasd_ccw_req *
+dasd_eckd_build_cp_discard(struct dasd_device *device, struct dasd_block *block,
+ struct request *req, sector_t first_trk,
+ sector_t last_trk)
+{
+ return dasd_eckd_dso_ras(device, block, req, first_trk, last_trk, 1);
+}
+
static struct dasd_ccw_req *dasd_eckd_build_cp_cmd_single(
struct dasd_device *startdev,
struct dasd_block *block,
@@ -4361,6 +4372,10 @@ static struct dasd_ccw_req *dasd_eckd_build_cp(struct dasd_device *startdev,
cmdwtd = private->features.feature[12] & 0x40;
use_prefix = private->features.feature[8] & 0x01;
+ if (req_op(req) == REQ_OP_DISCARD)
+ return dasd_eckd_build_cp_discard(startdev, block, req,
+ first_trk, last_trk);
+
cqr = NULL;
if (cdlspecial || dasd_page_cache) {
/* do nothing, just fall through to the cmd mode single case */
@@ -4639,12 +4654,14 @@ static struct dasd_ccw_req *dasd_eckd_build_alias_cp(struct dasd_device *base,
struct dasd_block *block,
struct request *req)
{
+ struct dasd_device *startdev = NULL;
struct dasd_eckd_private *private;
- struct dasd_device *startdev;
- unsigned long flags;
struct dasd_ccw_req *cqr;
+ unsigned long flags;
- startdev = dasd_alias_get_start_dev(base);
+ /* Discard requests can only be processed on base devices */
+ if (req_op(req) != REQ_OP_DISCARD)
+ startdev = dasd_alias_get_start_dev(base);
if (!startdev)
startdev = base;
private = startdev->private;
@@ -6357,8 +6374,20 @@ static void dasd_eckd_setup_blk_queue(struct dasd_block *block)
unsigned int logical_block_size = block->bp_block;
struct request_queue *q = block->request_queue;
struct dasd_device *device = block->base;
+ struct dasd_eckd_private *private;
+ unsigned int max_discard_sectors;
+ unsigned int max_bytes;
+ unsigned int ext_bytes; /* Extent Size in Bytes */
+ int recs_per_trk;
+ int trks_per_cyl;
+ int ext_limit;
+ int ext_size; /* Extent Size in Cylinders */
int max;
+ private = device->private;
+ trks_per_cyl = private->rdc_data.trk_per_cyl;
+ recs_per_trk = recs_per_track(&private->rdc_data, 0, logical_block_size);
+
if (device->features & DASD_FEATURE_USERAW) {
/*
* the max_blocks value for raw_track access is 256
@@ -6379,6 +6408,28 @@ static void dasd_eckd_setup_blk_queue(struct dasd_block *block)
/* With page sized segments each segment can be translated into one idaw/tidaw */
blk_queue_max_segment_size(q, PAGE_SIZE);
blk_queue_segment_boundary(q, PAGE_SIZE - 1);
+
+ if (dasd_eckd_is_ese(device)) {
+ /*
+ * Depending on the extent size, up to UINT_MAX bytes can be
+ * accepted. However, neither DASD_ECKD_RAS_EXTS_MAX nor the
+ * device limits should be exceeded.
+ */
+ ext_size = dasd_eckd_ext_size(device);
+ ext_limit = min(private->real_cyl / ext_size, DASD_ECKD_RAS_EXTS_MAX);
+ ext_bytes = ext_size * trks_per_cyl * recs_per_trk *
+ logical_block_size;
+ max_bytes = UINT_MAX - (UINT_MAX % ext_bytes);
+ if (max_bytes / ext_bytes > ext_limit)
+ max_bytes = ext_bytes * ext_limit;
+
+ max_discard_sectors = max_bytes / 512;
+
+ blk_queue_max_discard_sectors(q, max_discard_sectors);
+ blk_queue_flag_set(QUEUE_FLAG_DISCARD, q);
+ q->limits.discard_granularity = ext_bytes;
+ q->limits.discard_alignment = ext_bytes;
+ }
}
static struct ccw_driver dasd_eckd_driver = {
--
GitLab