[PATCH 0/2] s390/dasd: fixes for thin provisioning support

[PATCH 0/2] s390/dasd: fixes for thin provisioning support

[Stefan Haberland]

Hi Jens,

please see the following two patches that

- fix a bug in the thin provisioning base support
- revert a commit because of possible data corruption

Regards,
Stefan


Jan Höppner (1):
  s390/dasd: Fix error handling during online processing

Stefan Haberland (1):
  Revert "s390/dasd: Add discard support for ESE volumes"

 drivers/s390/block/dasd_eckd.c | 81 +++++-----------------------------
 1 file changed, 11 insertions(+), 70 deletions(-)

-- 
2.17.1

[PATCH 1/2] s390/dasd: Fix error handling during online processing

[Stefan Haberland]

From: Jan Höppner <hoeppner@linux.ibm.com>

It is possible that the CCW commands for reading volume and extent pool
information are not supported, either by the storage server (for
dedicated DASDs) or by z/VM (for virtual devices, such as MDISKs).

As a command reject will occur in such a case, the current error
handling leads to a failing online processing and thus the DASD can't be
used at all.

Since the data being read is not essential for an fully operational
DASD, the error handling can be removed. Information about the failing
command is sent to the s390dbf debug feature.

Fixes: c729696bcf8b ("s390/dasd: Recognise data for ESE volumes")
Cc: <stable@vger.kernel.org> # 5.3
Reported-by: Frank Heimes <frank.heimes@canonical.com>
Signed-off-by: Jan Höppner <hoeppner@linux.ibm.com>
Signed-off-by: Stefan Haberland <sth@linux.ibm.com>
---
 drivers/s390/block/dasd_eckd.c | 24 ++++++++----------------
 1 file changed, 8 insertions(+), 16 deletions(-)

diff --git a/drivers/s390/block/dasd_eckd.c b/drivers/s390/block/dasd_eckd.c
index fc53e1e221f0..b213c40d1a51 100644
--- a/drivers/s390/block/dasd_eckd.c
+++ b/drivers/s390/block/dasd_eckd.c
@@ -1553,8 +1553,8 @@ static int dasd_eckd_read_vol_info(struct dasd_device *device)
 	if (rc == 0) {
 		memcpy(&private->vsq, vsq, sizeof(*vsq));
 	} else {
-		dev_warn(&device->cdev->dev,
-			 "Reading the volume storage information failed with rc=%d\n", rc);
+		DBF_EVENT_DEVID(DBF_WARNING, device->cdev,
+				"Reading the volume storage information failed with rc=%d", rc);
 	}
 
 	if (useglobal)
@@ -1737,8 +1737,8 @@ static int dasd_eckd_read_ext_pool_info(struct dasd_device *device)
 	if (rc == 0) {
 		dasd_eckd_cpy_ext_pool_data(device, lcq);
 	} else {
-		dev_warn(&device->cdev->dev,
-			 "Reading the logical configuration failed with rc=%d\n", rc);
+		DBF_EVENT_DEVID(DBF_WARNING, device->cdev,
+				"Reading the logical configuration failed with rc=%d", rc);
 	}
 
 	dasd_sfree_request(cqr, cqr->memdev);
@@ -2020,14 +2020,10 @@ dasd_eckd_check_characteristics(struct dasd_device *device)
 	dasd_eckd_read_features(device);
 
 	/* Read Volume Information */
-	rc = dasd_eckd_read_vol_info(device);
-	if (rc)
-		goto out_err3;
+	dasd_eckd_read_vol_info(device);
 
 	/* Read Extent Pool Information */
-	rc = dasd_eckd_read_ext_pool_info(device);
-	if (rc)
-		goto out_err3;
+	dasd_eckd_read_ext_pool_info(device);
 
 	/* Read Device Characteristics */
 	rc = dasd_generic_read_dev_chars(device, DASD_ECKD_MAGIC,
@@ -5663,14 +5659,10 @@ static int dasd_eckd_restore_device(struct dasd_device *device)
 	dasd_eckd_read_features(device);
 
 	/* Read Volume Information */
-	rc = dasd_eckd_read_vol_info(device);
-	if (rc)
-		goto out_err2;
+	dasd_eckd_read_vol_info(device);
 
 	/* Read Extent Pool Information */
-	rc = dasd_eckd_read_ext_pool_info(device);
-	if (rc)
-		goto out_err2;
+	dasd_eckd_read_ext_pool_info(device);
 
 	/* Read Device Characteristics */
 	rc = dasd_generic_read_dev_chars(device, DASD_ECKD_MAGIC,
-- 
2.17.1

[PATCH 2/2] Revert "s390/dasd: Add discard support for ESE volumes"

[Stefan Haberland]

This reverts commit 7e64db1597fe114b83fe17d0ba96c6aa5fca419a.

The thin provisioning feature introduces an IOCTL and the discard support
to allow userspace tools and filesystems to release unused and previously
allocated space respectively.

During some internal performance improvements and further tests, the
release of allocated space revealed some issues that may lead to data
corruption in some configurations when filesystems are mounted with
discard support enabled.

While we're working on a fix and trying to clarify the situation,
this commit reverts the discard support for ESE volumes to prevent
potential data corruption.

Cc: <stable@vger.kernel.org> # 5.3
Signed-off-by: Stefan Haberland <sth@linux.ibm.com>
---
 drivers/s390/block/dasd_eckd.c | 57 ++--------------------------------
 1 file changed, 3 insertions(+), 54 deletions(-)

diff --git a/drivers/s390/block/dasd_eckd.c b/drivers/s390/block/dasd_eckd.c
index b213c40d1a51..c94184d080f8 100644
--- a/drivers/s390/block/dasd_eckd.c
+++ b/drivers/s390/block/dasd_eckd.c
@@ -2055,9 +2055,6 @@ 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,
@@ -3691,14 +3688,6 @@ 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,
@@ -4443,10 +4432,6 @@ 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 */
@@ -4725,14 +4710,12 @@ 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_ccw_req *cqr;
+	struct dasd_device *startdev;
 	unsigned long flags;
+	struct dasd_ccw_req *cqr;
 
-	/* Discard requests can only be processed on base devices */
-	if (req_op(req) != REQ_OP_DISCARD)
-		startdev = dasd_alias_get_start_dev(base);
+	startdev = dasd_alias_get_start_dev(base);
 	if (!startdev)
 		startdev = base;
 	private = startdev->private;
@@ -6513,20 +6496,8 @@ 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
@@ -6547,28 +6518,6 @@ 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 = {
-- 
2.17.1

Re: [PATCH 0/2] s390/dasd: fixes for thin provisioning support

[Jens Axboe]

On 10/1/19 9:34 AM, Stefan Haberland wrote:
> Hi Jens,
> 
> please see the following two patches that
> 
> - fix a bug in the thin provisioning base support
> - revert a commit because of possible data corruption

Applied, thanks Stefan.

-- 
Jens Axboe