[PATCH 0/2] Fix handling of host-aware ZBC disks

[PATCH 0/2] Fix handling of host-aware ZBC disks

[Damien Le Moal]

Martin,

Two patches for this cycle (with a cc stable) to fix handling of
host-aware ZBC disks that have partitions, that is, used as regular
disks.

The first patch fixes host-aware disk initialization and command
completion processing. It also enables the use of host-aware disks as
regular disks when CONFIG_BLK_DEV_ZONED is disabled.

The second patch fixes the CONFIG_BLK_DEV_ZONED enabled configuration
so that zone append emulation is not initialized for host-aware disks
with partitions/used as regular disks. While at it, this patch also
removes a problem with sd_zbc_init_disk() error handling in
sd_revalidate_disk() by moving this function execution inside
sd_zbc_revalidate_zones().

Boris,

I tested all this. I could recreate the hang you are seeing with
CONFIG_BLK_DEV_ZONED disabled. The cause for this hang was that
good_bytes always ended up being 0 for all IOs to the host-aware disk.
The fix for this is in the first patch.
If you could test this (on top of 5.9-rc), it would be great. Thanks !

Damien Le Moal (2):
  scsi: Fix handling of host-aware ZBC disks
  scsi: Fix ZBC disk initialization

 drivers/scsi/sd.c     | 26 +++++++++++------
 drivers/scsi/sd.h     |  8 +-----
 drivers/scsi/sd_zbc.c | 66 ++++++++++++++++++++++++++-----------------
 3 files changed, 59 insertions(+), 41 deletions(-)

-- 
2.26.2

[PATCH 1/2] scsi: Fix handling of host-aware ZBC disks

[Damien Le Moal]

When CONFIG_BLK_DEV_ZONED is disabled, allow using host-aware ZBC
disks as regular disks. In this case, ensure that command completion
is correctly executed by changing sd_zbc_complete() to return good_bytes
instead of 0, causing a hang during device probe (endless retries).

When CONFIG_BLK_DEV_ZONED is enabled and a host-aware disk is detected
to have partitions, it will be used as a regular disk. In this case,
make sure to not do anything in sd_zbc_revalidate_zones() as that
triggers warnings.

Reported-by: Borislav Petkov <bp@alien8.de>
Fixes: b72053072c0b ("block: allow partitions on host aware zone devices")
Cc: <stable@vger.kernel.org>
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
---
 drivers/scsi/sd.c     | 22 ++++++++++++++++++----
 drivers/scsi/sd.h     |  2 +-
 drivers/scsi/sd_zbc.c |  6 +++++-
 3 files changed, 24 insertions(+), 6 deletions(-)

diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index 95018e650f2d..7f0371185a45 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -2968,22 +2968,36 @@ static void sd_read_block_characteristics(struct scsi_disk *sdkp)
 	} else {
 		sdkp->zoned = (buffer[8] >> 4) & 3;
 		if (sdkp->zoned == 1 && !disk_has_partitions(sdkp->disk)) {
+#ifdef CONFIG_BLK_DEV_ZONED
 			/* Host-aware */
 			q->limits.zoned = BLK_ZONED_HA;
+#else
+			/* Host-aware drive is treated as a regular disk */
+			q->limits.zoned = BLK_ZONED_NONE;
+#endif
 		} else {
 			/*
 			 * Treat drive-managed devices and host-aware devices
 			 * with partitions as regular block devices.
 			 */
 			q->limits.zoned = BLK_ZONED_NONE;
-			if (sdkp->zoned == 2 && sdkp->first_scan)
-				sd_printk(KERN_NOTICE, sdkp,
-					  "Drive-managed SMR disk\n");
 		}
 	}
-	if (blk_queue_is_zoned(q) && sdkp->first_scan)
+
+	if (!sdkp->first_scan)
+		goto out;
+
+	if (blk_queue_is_zoned(q)) {
 		sd_printk(KERN_NOTICE, sdkp, "Host-%s zoned block device\n",
 		      q->limits.zoned == BLK_ZONED_HM ? "managed" : "aware");
+	} else {
+		if (sdkp->zoned == 1)
+			sd_printk(KERN_NOTICE, sdkp,
+				  "Host-aware SMR disk used as regular disk\n");
+		else if (sdkp->zoned == 2)
+			sd_printk(KERN_NOTICE, sdkp,
+				  "Drive-managed SMR disk\n");
+	}
 
  out:
 	kfree(buffer);
diff --git a/drivers/scsi/sd.h b/drivers/scsi/sd.h
index 4933e7daf17d..7251434100e6 100644
--- a/drivers/scsi/sd.h
+++ b/drivers/scsi/sd.h
@@ -259,7 +259,7 @@ static inline blk_status_t sd_zbc_setup_zone_mgmt_cmnd(struct scsi_cmnd *cmd,
 static inline unsigned int sd_zbc_complete(struct scsi_cmnd *cmd,
 			unsigned int good_bytes, struct scsi_sense_hdr *sshdr)
 {
-	return 0;
+	return good_bytes;
 }
 
 static inline blk_status_t sd_zbc_prepare_zone_append(struct scsi_cmnd *cmd,
diff --git a/drivers/scsi/sd_zbc.c b/drivers/scsi/sd_zbc.c
index 0e94ff056bff..a739456dea02 100644
--- a/drivers/scsi/sd_zbc.c
+++ b/drivers/scsi/sd_zbc.c
@@ -667,7 +667,11 @@ int sd_zbc_revalidate_zones(struct scsi_disk *sdkp)
 	u32 max_append;
 	int ret = 0;
 
-	if (!sd_is_zoned(sdkp))
+	/*
+	 * There is nothing to do for regular disks, including host-aware disks
+	 * that have partitions.
+	 */
+	if (!blk_queue_is_zoned(q))
 		return 0;
 
 	/*
-- 
2.26.2

[PATCH 2/2] scsi: Fix ZBC disk initialization

[Damien Le Moal]

Make sure to call sd_zbc_init_disk() when the sdkp->zoned field is
known, that is, once sd_read_block_characteristics() is executed in
sd_revalidate_disk(), so that host-aware disks also get initialized.
To do so, move sd_zbc_init_disk() call in sd_zbc_revalidate_zones() and
make sure to execute it for all zoned disks, including for host-aware
disks used as regular disks as these disk zoned model may be changed
back to BLK_ZONED_HA when partitions are deleted.

Reported-by: Borislav Petkov <bp@alien8.de>
Fixes: 5795eb443060 ("scsi: sd_zbc: emulate ZONE_APPEND commands")
Cc: <stable@vger.kernel.org> # v5.8+
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
---
 drivers/scsi/sd.c     |  4 ---
 drivers/scsi/sd.h     |  6 -----
 drivers/scsi/sd_zbc.c | 60 +++++++++++++++++++++++++------------------
 3 files changed, 35 insertions(+), 35 deletions(-)

diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index 7f0371185a45..3d2cffb8e9aa 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -3418,10 +3418,6 @@ static int sd_probe(struct device *dev)
 	sdkp->first_scan = 1;
 	sdkp->max_medium_access_timeouts = SD_MAX_MEDIUM_TIMEOUTS;
 
-	error = sd_zbc_init_disk(sdkp);
-	if (error)
-		goto out_free_index;
-
 	sd_revalidate_disk(gd);
 
 	gd->flags = GENHD_FL_EXT_DEVT;
diff --git a/drivers/scsi/sd.h b/drivers/scsi/sd.h
index 7251434100e6..a3aad608bc38 100644
--- a/drivers/scsi/sd.h
+++ b/drivers/scsi/sd.h
@@ -215,7 +215,6 @@ static inline int sd_is_zoned(struct scsi_disk *sdkp)
 
 #ifdef CONFIG_BLK_DEV_ZONED
 
-int sd_zbc_init_disk(struct scsi_disk *sdkp);
 void sd_zbc_release_disk(struct scsi_disk *sdkp);
 int sd_zbc_read_zones(struct scsi_disk *sdkp, unsigned char *buffer);
 int sd_zbc_revalidate_zones(struct scsi_disk *sdkp);
@@ -231,11 +230,6 @@ blk_status_t sd_zbc_prepare_zone_append(struct scsi_cmnd *cmd, sector_t *lba,
 
 #else /* CONFIG_BLK_DEV_ZONED */
 
-static inline int sd_zbc_init_disk(struct scsi_disk *sdkp)
-{
-	return 0;
-}
-
 static inline void sd_zbc_release_disk(struct scsi_disk *sdkp) {}
 
 static inline int sd_zbc_read_zones(struct scsi_disk *sdkp,
diff --git a/drivers/scsi/sd_zbc.c b/drivers/scsi/sd_zbc.c
index a739456dea02..cf07b7f93579 100644
--- a/drivers/scsi/sd_zbc.c
+++ b/drivers/scsi/sd_zbc.c
@@ -651,6 +651,28 @@ static void sd_zbc_print_zones(struct scsi_disk *sdkp)
 			  sdkp->zone_blocks);
 }
 
+static int sd_zbc_init_disk(struct scsi_disk *sdkp)
+{
+	sdkp->zones_wp_offset = NULL;
+	spin_lock_init(&sdkp->zones_wp_offset_lock);
+	sdkp->rev_wp_offset = NULL;
+	mutex_init(&sdkp->rev_mutex);
+	INIT_WORK(&sdkp->zone_wp_offset_work, sd_zbc_update_wp_offset_workfn);
+	sdkp->zone_wp_update_buf = kzalloc(SD_BUF_SIZE, GFP_KERNEL);
+	if (!sdkp->zone_wp_update_buf)
+		return -ENOMEM;
+
+	return 0;
+}
+
+void sd_zbc_release_disk(struct scsi_disk *sdkp)
+{
+	kvfree(sdkp->zones_wp_offset);
+	sdkp->zones_wp_offset = NULL;
+	kfree(sdkp->zone_wp_update_buf);
+	sdkp->zone_wp_update_buf = NULL;
+}
+
 static void sd_zbc_revalidate_zones_cb(struct gendisk *disk)
 {
 	struct scsi_disk *sdkp = scsi_disk(disk);
@@ -667,6 +689,19 @@ int sd_zbc_revalidate_zones(struct scsi_disk *sdkp)
 	u32 max_append;
 	int ret = 0;
 
+	/*
+	 * For all zoned disks, initialize zone append emulation data if not
+	 * already done. This is necessary also for host-aware disks used as
+	 * regular disks due to the presence of partitions as these partitions
+	 * may be deleted and the disk zoned model changed back from
+	 * BLK_ZONED_NONE to BLK_ZONED_HA.
+	 */
+	if (sd_is_zoned(sdkp) && !sdkp->zone_wp_update_buf) {
+		ret = sd_zbc_init_disk(sdkp);
+		if (ret)
+			return ret;
+	}
+
 	/*
 	 * There is nothing to do for regular disks, including host-aware disks
 	 * that have partitions.
@@ -768,28 +803,3 @@ int sd_zbc_read_zones(struct scsi_disk *sdkp, unsigned char *buf)
 
 	return ret;
 }
-
-int sd_zbc_init_disk(struct scsi_disk *sdkp)
-{
-	if (!sd_is_zoned(sdkp))
-		return 0;
-
-	sdkp->zones_wp_offset = NULL;
-	spin_lock_init(&sdkp->zones_wp_offset_lock);
-	sdkp->rev_wp_offset = NULL;
-	mutex_init(&sdkp->rev_mutex);
-	INIT_WORK(&sdkp->zone_wp_offset_work, sd_zbc_update_wp_offset_workfn);
-	sdkp->zone_wp_update_buf = kzalloc(SD_BUF_SIZE, GFP_KERNEL);
-	if (!sdkp->zone_wp_update_buf)
-		return -ENOMEM;
-
-	return 0;
-}
-
-void sd_zbc_release_disk(struct scsi_disk *sdkp)
-{
-	kvfree(sdkp->zones_wp_offset);
-	sdkp->zones_wp_offset = NULL;
-	kfree(sdkp->zone_wp_update_buf);
-	sdkp->zone_wp_update_buf = NULL;
-}
-- 
2.26.2

Re: [PATCH 0/2] Fix handling of host-aware ZBC disks

[Borislav Petkov]

Mornin',

On Sun, Sep 13, 2020 at 03:03:02PM +0900, Damien Le Moal wrote:
> I tested all this. I could recreate the hang you are seeing with
> CONFIG_BLK_DEV_ZONED disabled. The cause for this hang was that
> good_bytes always ended up being 0 for all IOs to the host-aware disk.
> The fix for this is in the first patch.
> If you could test this (on top of 5.9-rc), it would be great. Thanks !

Sure, below is the diff of both boot dmesgs, with CONFIG_BLK_DEV_ZONED
and without it. So for both:

Tested-by: Borislav Petkov <bp@suse.de>

Thanks Damien and sorry for ruining your weekend.

---
--- 09-rc4+.CONFIG_BLK_DEV_ZONED	2020-09-13 08:36:13.423999302 +0200
+++ 09-rc4+.CONFIG_BLK_DEV_ZONED.off	2020-09-13 08:43:45.371999496 +0200
@@ -825,28 +825,26 @@ input: DATACOMP SteelS쀁̄Љ̒DATA Cons
 hid-generic 0003:04B4:0101.0002: input,hidraw1: USB HID v1.00 Device [DATACOMP SteelS쀁̄Љ̒DATA] on usb-0000:03:00.0-12/input1
 usb 1-13: new low-speed USB device number 3 using xhci_hcd
 usb 1-13: New USB device found, idVendor=046d, idProduct=c018, bcdDevice=43.01
-ata4: SATA link up 6.0 Gbps (SStatus 133 SControl 300)
 usb 1-13: New USB device strings: Mfr=1, Product=2, SerialNumber=0
-ata4.00: NCQ Send/Recv Log not supported
 usb 1-13: Product: USB Optical Mouse
 usb 1-13: Manufacturer: Logitech
+ata4: SATA link up 6.0 Gbps (SStatus 133 SControl 300)
+ata4.00: NCQ Send/Recv Log not supported
 ata4.00: ATA-10: ST8000AS0022-1WL17Z, SN01, max UDMA/133
-ata4.00: 15628053168 sectors, multi 16: LBA48 NCQ (depth 32), AA
 input: Logitech USB Optical Mouse as /devices/pci0000:00/0000:00:01.3/0000:03:00.0/usb1/1-13/1-13:1.0/0003:046D:C018.0003/input/input5
+ata4.00: 15628053168 sectors, multi 16: LBA48 NCQ (depth 32), AA
 ata4.00: NCQ Send/Recv Log not supported
 hid-generic 0003:046D:C018.0003: input,hidraw2: USB HID v1.11 Mouse [Logitech USB Optical Mouse] on usb-0000:03:00.0-13/input0
 ata4.00: configured for UDMA/133
 scsi 3:0:0:0: Direct-Access     ATA      ST8000AS0022-1WL SN01 PQ: 0 ANSI: 5
 sd 3:0:0:0: Attached scsi generic sg1 type 0
-sd 3:0:0:0: [sdb] Host-aware zoned block device
+sd 3:0:0:0: [sdb] Host-aware SMR disk used as regular disk
 sd 3:0:0:0: [sdb] 15628053168 512-byte logical blocks: (8.00 TB/7.28 TiB)
 sd 3:0:0:0: [sdb] 4096-byte physical blocks
 sd 3:0:0:0: [sdb] Write Protect is off
 sd 3:0:0:0: [sdb] Mode Sense: 00 3a 00 00
 sd 3:0:0:0: [sdb] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA
-sd 3:0:0:0: [sdb] 29808 zones of 524288 logical blocks + 1 runt zone
  sdb: sdb1
-sdb: disabling host aware zoned block device support due to partitions
 sd 3:0:0:0: [sdb] Attached SCSI disk
 ata5: failed to resume link (SControl 0)
 ata5: SATA link down (SStatus 0 SControl 0)

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette

Re: [PATCH 1/2] scsi: Fix handling of host-aware ZBC disks

[Borislav Petkov]

On Sun, Sep 13, 2020 at 03:03:03PM +0900, Damien Le Moal wrote:
> diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
> index 95018e650f2d..7f0371185a45 100644
> --- a/drivers/scsi/sd.c
> +++ b/drivers/scsi/sd.c
> @@ -2968,22 +2968,36 @@ static void sd_read_block_characteristics(struct scsi_disk *sdkp)
>  	} else {
>  		sdkp->zoned = (buffer[8] >> 4) & 3;
>  		if (sdkp->zoned == 1 && !disk_has_partitions(sdkp->disk)) {
> +#ifdef CONFIG_BLK_DEV_ZONED

You could make that

		if (IS_ENABLED(CONFIG_BLK_DEV_ZONED))

and get rid of the ugly ifdeffery.

Just a nitpick anyway.

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette

Re: [PATCH 1/2] scsi: Fix handling of host-aware ZBC disks

[Johannes Thumshirn]

With Boris' comment worked in,
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>

Re: [PATCH 2/2] scsi: Fix ZBC disk initialization

[Johannes Thumshirn]

Looks good,
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>