block: remove the discard_zeroes_data flag
Now that we use the proper REQ_OP_WRITE_ZEROES operation everywhere we can
kill this hack.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
diff --git a/Documentation/ABI/testing/sysfs-block b/Documentation/ABI/testing/sysfs-block
index 2da04ce..dea212d 100644
--- a/Documentation/ABI/testing/sysfs-block
+++ b/Documentation/ABI/testing/sysfs-block
@@ -213,14 +213,8 @@
Date: May 2011
Contact: Martin K. Petersen <martin.petersen@oracle.com>
Description:
- Devices that support discard functionality may return
- stale or random data when a previously discarded block
- is read back. This can cause problems if the filesystem
- expects discarded blocks to be explicitly cleared. If a
- device reports that it deterministically returns zeroes
- when a discarded area is read the discard_zeroes_data
- parameter will be set to one. Otherwise it will be 0 and
- the result of reading a discarded area is undefined.
+ Will always return 0. Don't rely on any specific behavior
+ for discards, and don't read this file.
What: /sys/block/<disk>/queue/write_same_max_bytes
Date: January 2012
diff --git a/Documentation/block/queue-sysfs.txt b/Documentation/block/queue-sysfs.txt
index b7f6bdc..2c1e670 100644
--- a/Documentation/block/queue-sysfs.txt
+++ b/Documentation/block/queue-sysfs.txt
@@ -43,11 +43,6 @@
smaller discards and potentially help reduce latencies induced by large
discard operations.
-discard_zeroes_data (RO)
-------------------------
-When read, this file will show if the discarded block are zeroed by the
-device or not. If its value is '1' the blocks are zeroed otherwise not.
-
hw_sector_size (RO)
-------------------
This is the hardware sector size of the device, in bytes.
diff --git a/block/blk-lib.c b/block/blk-lib.c
index b0c6c4b..e8caecd 100644
--- a/block/blk-lib.c
+++ b/block/blk-lib.c
@@ -37,17 +37,12 @@
return -ENXIO;
if (flags & BLKDEV_DISCARD_SECURE) {
- if (flags & BLKDEV_DISCARD_ZERO)
- return -EOPNOTSUPP;
if (!blk_queue_secure_erase(q))
return -EOPNOTSUPP;
op = REQ_OP_SECURE_ERASE;
} else {
if (!blk_queue_discard(q))
return -EOPNOTSUPP;
- if ((flags & BLKDEV_DISCARD_ZERO) &&
- !q->limits.discard_zeroes_data)
- return -EOPNOTSUPP;
op = REQ_OP_DISCARD;
}
@@ -126,7 +121,7 @@
&bio);
if (!ret && bio) {
ret = submit_bio_wait(bio);
- if (ret == -EOPNOTSUPP && !(flags & BLKDEV_DISCARD_ZERO))
+ if (ret == -EOPNOTSUPP)
ret = 0;
bio_put(bio);
}
diff --git a/block/blk-settings.c b/block/blk-settings.c
index 1e7174f..4fa81ed3 100644
--- a/block/blk-settings.c
+++ b/block/blk-settings.c
@@ -103,7 +103,6 @@
lim->discard_granularity = 0;
lim->discard_alignment = 0;
lim->discard_misaligned = 0;
- lim->discard_zeroes_data = 0;
lim->logical_block_size = lim->physical_block_size = lim->io_min = 512;
lim->bounce_pfn = (unsigned long)(BLK_BOUNCE_ANY >> PAGE_SHIFT);
lim->alignment_offset = 0;
@@ -127,7 +126,6 @@
blk_set_default_limits(lim);
/* Inherit limits from component devices */
- lim->discard_zeroes_data = 1;
lim->max_segments = USHRT_MAX;
lim->max_discard_segments = 1;
lim->max_hw_sectors = UINT_MAX;
@@ -609,7 +607,6 @@
t->io_opt = lcm_not_zero(t->io_opt, b->io_opt);
t->cluster &= b->cluster;
- t->discard_zeroes_data &= b->discard_zeroes_data;
/* Physical block size a multiple of the logical block size? */
if (t->physical_block_size & (t->logical_block_size - 1)) {
diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c
index c47db43..fc20489 100644
--- a/block/blk-sysfs.c
+++ b/block/blk-sysfs.c
@@ -208,7 +208,7 @@
static ssize_t queue_discard_zeroes_data_show(struct request_queue *q, char *page)
{
- return queue_var_show(queue_discard_zeroes_data(q), page);
+ return queue_var_show(0, page);
}
static ssize_t queue_write_same_max_show(struct request_queue *q, char *page)
diff --git a/block/compat_ioctl.c b/block/compat_ioctl.c
index 570021a..04325b8 100644
--- a/block/compat_ioctl.c
+++ b/block/compat_ioctl.c
@@ -685,7 +685,7 @@
case BLKALIGNOFF:
return compat_put_int(arg, bdev_alignment_offset(bdev));
case BLKDISCARDZEROES:
- return compat_put_uint(arg, bdev_discard_zeroes_data(bdev));
+ return compat_put_uint(arg, 0);
case BLKFLSBUF:
case BLKROSET:
case BLKDISCARD:
diff --git a/block/ioctl.c b/block/ioctl.c
index 8ea00a4..0de02ee 100644
--- a/block/ioctl.c
+++ b/block/ioctl.c
@@ -547,7 +547,7 @@
case BLKALIGNOFF:
return put_int(arg, bdev_alignment_offset(bdev));
case BLKDISCARDZEROES:
- return put_uint(arg, bdev_discard_zeroes_data(bdev));
+ return put_uint(arg, 0);
case BLKSECTGET:
max_sectors = min_t(unsigned int, USHRT_MAX,
queue_max_sectors(bdev_get_queue(bdev)));
diff --git a/drivers/block/drbd/drbd_main.c b/drivers/block/drbd/drbd_main.c
index 8e62d9f..84455c3 100644
--- a/drivers/block/drbd/drbd_main.c
+++ b/drivers/block/drbd/drbd_main.c
@@ -931,7 +931,6 @@
p->qlim->io_min = cpu_to_be32(queue_io_min(q));
p->qlim->io_opt = cpu_to_be32(queue_io_opt(q));
p->qlim->discard_enabled = blk_queue_discard(q);
- p->qlim->discard_zeroes_data = queue_discard_zeroes_data(q);
p->qlim->write_same_capable = !!q->limits.max_write_same_sectors;
} else {
q = device->rq_queue;
@@ -941,7 +940,6 @@
p->qlim->io_min = cpu_to_be32(queue_io_min(q));
p->qlim->io_opt = cpu_to_be32(queue_io_opt(q));
p->qlim->discard_enabled = 0;
- p->qlim->discard_zeroes_data = 0;
p->qlim->write_same_capable = 0;
}
}
diff --git a/drivers/block/drbd/drbd_nl.c b/drivers/block/drbd/drbd_nl.c
index e4516d3..02255a0 100644
--- a/drivers/block/drbd/drbd_nl.c
+++ b/drivers/block/drbd/drbd_nl.c
@@ -1199,10 +1199,6 @@
struct drbd_connection *connection = first_peer_device(device)->connection;
bool can_do = b ? blk_queue_discard(b) : true;
- if (can_do && b && !b->limits.discard_zeroes_data && !discard_zeroes_if_aligned) {
- can_do = false;
- drbd_info(device, "discard_zeroes_data=0 and discard_zeroes_if_aligned=no: disabling discards\n");
- }
if (can_do && connection->cstate >= C_CONNECTED && !(connection->agreed_features & DRBD_FF_TRIM)) {
can_do = false;
drbd_info(connection, "peer DRBD too old, does not support TRIM: disabling discards\n");
@@ -1484,8 +1480,7 @@
if (disk_conf->al_extents > drbd_al_extents_max(nbc))
disk_conf->al_extents = drbd_al_extents_max(nbc);
- if (!blk_queue_discard(q)
- || (!q->limits.discard_zeroes_data && !disk_conf->discard_zeroes_if_aligned)) {
+ if (!blk_queue_discard(q)) {
if (disk_conf->rs_discard_granularity) {
disk_conf->rs_discard_granularity = 0; /* disable feature */
drbd_info(device, "rs_discard_granularity feature disabled\n");
diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index 3bb04c1..3081d83 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -828,7 +828,6 @@
q->limits.discard_alignment = 0;
blk_queue_max_discard_sectors(q, 0);
blk_queue_max_write_zeroes_sectors(q, 0);
- q->limits.discard_zeroes_data = 0;
queue_flag_clear_unlocked(QUEUE_FLAG_DISCARD, q);
return;
}
@@ -837,7 +836,6 @@
q->limits.discard_alignment = 0;
blk_queue_max_discard_sectors(q, UINT_MAX >> 9);
blk_queue_max_write_zeroes_sectors(q, UINT_MAX >> 9);
- q->limits.discard_zeroes_data = 1;
queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, q);
}
diff --git a/drivers/block/mtip32xx/mtip32xx.c b/drivers/block/mtip32xx/mtip32xx.c
index 30076e7..05e3e66 100644
--- a/drivers/block/mtip32xx/mtip32xx.c
+++ b/drivers/block/mtip32xx/mtip32xx.c
@@ -4025,7 +4025,6 @@
dd->queue->limits.discard_granularity = 4096;
blk_queue_max_discard_sectors(dd->queue,
MTIP_MAX_TRIM_ENTRY_LEN * MTIP_MAX_TRIM_ENTRIES);
- dd->queue->limits.discard_zeroes_data = 0;
}
/* Set the capacity of the device in 512 byte sectors. */
diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
index 03ae729..b02f236 100644
--- a/drivers/block/nbd.c
+++ b/drivers/block/nbd.c
@@ -1110,7 +1110,6 @@
queue_flag_clear_unlocked(QUEUE_FLAG_ADD_RANDOM, disk->queue);
disk->queue->limits.discard_granularity = 512;
blk_queue_max_discard_sectors(disk->queue, UINT_MAX);
- disk->queue->limits.discard_zeroes_data = 0;
blk_queue_max_hw_sectors(disk->queue, 65536);
disk->queue->limits.max_sectors = 256;
diff --git a/drivers/md/dm-cache-target.c b/drivers/md/dm-cache-target.c
index 9c689b3..975922c8 100644
--- a/drivers/md/dm-cache-target.c
+++ b/drivers/md/dm-cache-target.c
@@ -2773,7 +2773,6 @@
ti->num_discard_bios = 1;
ti->discards_supported = true;
- ti->discard_zeroes_data_unsupported = true;
ti->split_discard_bios = false;
cache->features = ca->features;
diff --git a/drivers/md/dm-crypt.c b/drivers/md/dm-crypt.c
index 389a363..ef1d836 100644
--- a/drivers/md/dm-crypt.c
+++ b/drivers/md/dm-crypt.c
@@ -2030,7 +2030,6 @@
wake_up_process(cc->write_thread);
ti->num_flush_bios = 1;
- ti->discard_zeroes_data_unsupported = true;
return 0;
diff --git a/drivers/md/dm-raid.c b/drivers/md/dm-raid.c
index f8564d6..468f138 100644
--- a/drivers/md/dm-raid.c
+++ b/drivers/md/dm-raid.c
@@ -2813,7 +2813,9 @@
/* Assume discards not supported until after checks below. */
ti->discards_supported = false;
- /* RAID level 4,5,6 require discard_zeroes_data for data integrity! */
+ /*
+ * XXX: RAID level 4,5,6 require zeroing for safety.
+ */
raid456 = (rs->md.level == 4 || rs->md.level == 5 || rs->md.level == 6);
for (i = 0; i < rs->raid_disks; i++) {
@@ -2827,8 +2829,6 @@
return;
if (raid456) {
- if (!q->limits.discard_zeroes_data)
- return;
if (!devices_handle_discard_safely) {
DMERR("raid456 discard support disabled due to discard_zeroes_data uncertainty.");
DMERR("Set dm-raid.devices_handle_discard_safely=Y to override.");
diff --git a/drivers/md/dm-raid1.c b/drivers/md/dm-raid1.c
index 2ddc2d2..a95cbb8 100644
--- a/drivers/md/dm-raid1.c
+++ b/drivers/md/dm-raid1.c
@@ -1124,7 +1124,6 @@
ti->num_flush_bios = 1;
ti->num_discard_bios = 1;
ti->per_io_data_size = sizeof(struct dm_raid1_bio_record);
- ti->discard_zeroes_data_unsupported = true;
ms->kmirrord_wq = alloc_workqueue("kmirrord", WQ_MEM_RECLAIM, 0);
if (!ms->kmirrord_wq) {
diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c
index 5cd665c..958275a 100644
--- a/drivers/md/dm-table.c
+++ b/drivers/md/dm-table.c
@@ -1449,22 +1449,6 @@
return false;
}
-static bool dm_table_discard_zeroes_data(struct dm_table *t)
-{
- struct dm_target *ti;
- unsigned i = 0;
-
- /* Ensure that all targets supports discard_zeroes_data. */
- while (i < dm_table_get_num_targets(t)) {
- ti = dm_table_get_target(t, i++);
-
- if (ti->discard_zeroes_data_unsupported)
- return false;
- }
-
- return true;
-}
-
static int device_is_nonrot(struct dm_target *ti, struct dm_dev *dev,
sector_t start, sector_t len, void *data)
{
@@ -1620,9 +1604,6 @@
}
blk_queue_write_cache(q, wc, fua);
- if (!dm_table_discard_zeroes_data(t))
- q->limits.discard_zeroes_data = 0;
-
/* Ensure that all underlying devices are non-rotational. */
if (dm_table_all_devices_attribute(t, device_is_nonrot))
queue_flag_set_unlocked(QUEUE_FLAG_NONROT, q);
diff --git a/drivers/md/dm-thin.c b/drivers/md/dm-thin.c
index 2b266a2..a5f1916 100644
--- a/drivers/md/dm-thin.c
+++ b/drivers/md/dm-thin.c
@@ -3263,7 +3263,6 @@
* them down to the data device. The thin device's discard
* processing will cause mappings to be removed from the btree.
*/
- ti->discard_zeroes_data_unsupported = true;
if (pf.discard_enabled && pf.discard_passdown) {
ti->num_discard_bios = 1;
@@ -4119,7 +4118,6 @@
ti->per_io_data_size = sizeof(struct dm_thin_endio_hook);
/* In case the pool supports discards, pass them on. */
- ti->discard_zeroes_data_unsupported = true;
if (tc->pool->pf.discard_enabled) {
ti->discards_supported = true;
ti->num_discard_bios = 1;
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index 1725a54..2efdb0d 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -7227,7 +7227,6 @@
if (mddev->queue) {
int chunk_size;
- bool discard_supported = true;
/* read-ahead size must cover two whole stripes, which
* is 2 * (datadisks) * chunksize where 'n' is the
* number of raid devices
@@ -7263,12 +7262,6 @@
blk_queue_max_discard_sectors(mddev->queue,
0xfffe * STRIPE_SECTORS);
- /*
- * unaligned part of discard request will be ignored, so can't
- * guarantee discard_zeroes_data
- */
- mddev->queue->limits.discard_zeroes_data = 0;
-
blk_queue_max_write_same_sectors(mddev->queue, 0);
blk_queue_max_write_zeroes_sectors(mddev->queue, 0);
@@ -7277,35 +7270,24 @@
rdev->data_offset << 9);
disk_stack_limits(mddev->gendisk, rdev->bdev,
rdev->new_data_offset << 9);
- /*
- * discard_zeroes_data is required, otherwise data
- * could be lost. Consider a scenario: discard a stripe
- * (the stripe could be inconsistent if
- * discard_zeroes_data is 0); write one disk of the
- * stripe (the stripe could be inconsistent again
- * depending on which disks are used to calculate
- * parity); the disk is broken; The stripe data of this
- * disk is lost.
- */
- if (!blk_queue_discard(bdev_get_queue(rdev->bdev)) ||
- !bdev_get_queue(rdev->bdev)->
- limits.discard_zeroes_data)
- discard_supported = false;
- /* Unfortunately, discard_zeroes_data is not currently
- * a guarantee - just a hint. So we only allow DISCARD
- * if the sysadmin has confirmed that only safe devices
- * are in use by setting a module parameter.
- */
- if (!devices_handle_discard_safely) {
- if (discard_supported) {
- pr_info("md/raid456: discard support disabled due to uncertainty.\n");
- pr_info("Set raid456.devices_handle_discard_safely=Y to override.\n");
- }
- discard_supported = false;
- }
}
- if (discard_supported &&
+ /*
+ * zeroing is required, otherwise data
+ * could be lost. Consider a scenario: discard a stripe
+ * (the stripe could be inconsistent if
+ * discard_zeroes_data is 0); write one disk of the
+ * stripe (the stripe could be inconsistent again
+ * depending on which disks are used to calculate
+ * parity); the disk is broken; The stripe data of this
+ * disk is lost.
+ *
+ * We only allow DISCARD if the sysadmin has confirmed that
+ * only safe devices are in use by setting a module parameter.
+ * A better idea might be to turn DISCARD into WRITE_ZEROES
+ * requests, as that is required to be safe.
+ */
+ if (devices_handle_discard_safely &&
mddev->queue->limits.max_discard_sectors >= (stripe >> 9) &&
mddev->queue->limits.discard_granularity >= stripe)
queue_flag_set_unlocked(QUEUE_FLAG_DISCARD,
diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index 001593e..bcb0cb0 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -644,8 +644,6 @@
unsigned int logical_block_size = sdkp->device->sector_size;
unsigned int max_blocks = 0;
- q->limits.discard_zeroes_data = 0;
-
/*
* When LBPRZ is reported, discard alignment and granularity
* must be fixed to the logical block size. Otherwise the block
@@ -681,19 +679,16 @@
case SD_LBP_WS16:
max_blocks = min_not_zero(sdkp->max_ws_blocks,
(u32)SD_MAX_WS16_BLOCKS);
- q->limits.discard_zeroes_data = sdkp->lbprz;
break;
case SD_LBP_WS10:
max_blocks = min_not_zero(sdkp->max_ws_blocks,
(u32)SD_MAX_WS10_BLOCKS);
- q->limits.discard_zeroes_data = sdkp->lbprz;
break;
case SD_LBP_ZERO:
max_blocks = min_not_zero(sdkp->max_ws_blocks,
(u32)SD_MAX_WS10_BLOCKS);
- q->limits.discard_zeroes_data = 1;
break;
}
diff --git a/drivers/target/target_core_device.c b/drivers/target/target_core_device.c
index c754ae3..d2f089c 100644
--- a/drivers/target/target_core_device.c
+++ b/drivers/target/target_core_device.c
@@ -851,7 +851,7 @@
attrib->unmap_granularity = q->limits.discard_granularity / block_size;
attrib->unmap_granularity_alignment = q->limits.discard_alignment /
block_size;
- attrib->unmap_zeroes_data = q->limits.discard_zeroes_data;
+ attrib->unmap_zeroes_data = 0;
return true;
}
EXPORT_SYMBOL(target_configure_unmap_from_queue);
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 21a30f0..ec99357 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -339,7 +339,6 @@
unsigned char misaligned;
unsigned char discard_misaligned;
unsigned char cluster;
- unsigned char discard_zeroes_data;
unsigned char raid_partial_stripes_expensive;
enum blk_zoned_model zoned;
};
@@ -1341,7 +1340,6 @@
sector_t nr_sects, gfp_t gfp_mask, struct page *page);
#define BLKDEV_DISCARD_SECURE (1 << 0) /* issue a secure erase */
-#define BLKDEV_DISCARD_ZERO (1 << 1) /* must reliably zero data */
extern int blkdev_issue_discard(struct block_device *bdev, sector_t sector,
sector_t nr_sects, gfp_t gfp_mask, unsigned long flags);
@@ -1541,19 +1539,6 @@
return q->limits.discard_alignment;
}
-static inline unsigned int queue_discard_zeroes_data(struct request_queue *q)
-{
- if (q->limits.max_discard_sectors && q->limits.discard_zeroes_data == 1)
- return 1;
-
- return 0;
-}
-
-static inline unsigned int bdev_discard_zeroes_data(struct block_device *bdev)
-{
- return queue_discard_zeroes_data(bdev_get_queue(bdev));
-}
-
static inline unsigned int bdev_write_same(struct block_device *bdev)
{
struct request_queue *q = bdev_get_queue(bdev);
diff --git a/include/linux/device-mapper.h b/include/linux/device-mapper.h
index 3829bee..c7ea33e 100644
--- a/include/linux/device-mapper.h
+++ b/include/linux/device-mapper.h
@@ -296,11 +296,6 @@
* on max_io_len boundary.
*/
bool split_discard_bios:1;
-
- /*
- * Set if this target does not return zeroes on discarded blocks.
- */
- bool discard_zeroes_data_unsupported:1;
};
/* Each target can link one of these into the table */