Commit 48920ff2 authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Jens Axboe

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: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: Martin K. Petersen's avatarMartin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: default avatarHannes Reinecke <hare@suse.com>
Signed-off-by: default avatarJens Axboe <axboe@fb.com>
parent 45c21793
......@@ -213,14 +213,8 @@ What: /sys/block/<disk>/queue/discard_zeroes_data
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
......
......@@ -43,11 +43,6 @@ large discards are issued, setting this value lower will make Linux issue
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.
......
......@@ -37,17 +37,12 @@ int __blkdev_issue_discard(struct block_device *bdev, sector_t sector,
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 @@ int blkdev_issue_discard(struct block_device *bdev, sector_t sector,
&bio);
if (!ret && bio) {
ret = submit_bio_wait(bio);
if (ret == -EOPNOTSUPP && !(flags & BLKDEV_DISCARD_ZERO))
if (ret == -EOPNOTSUPP)
ret = 0;
bio_put(bio);
}
......
......@@ -103,7 +103,6 @@ void blk_set_default_limits(struct queue_limits *lim)
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 @@ void blk_set_stacking_limits(struct queue_limits *lim)
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 @@ int blk_stack_limits(struct queue_limits *t, struct queue_limits *b,
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)) {
......
......@@ -208,7 +208,7 @@ static ssize_t queue_discard_max_store(struct request_queue *q,
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)
......
......@@ -685,7 +685,7 @@ long compat_blkdev_ioctl(struct file *file, unsigned cmd, unsigned long arg)
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:
......
......@@ -547,7 +547,7 @@ int blkdev_ioctl(struct block_device *bdev, fmode_t mode, unsigned cmd,
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)));
......
......@@ -931,7 +931,6 @@ void assign_p_sizes_qlim(struct drbd_device *device, struct p_sizes *p, struct r
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 @@ void assign_p_sizes_qlim(struct drbd_device *device, struct p_sizes *p, struct r
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;
}
}
......
......@@ -1199,10 +1199,6 @@ static void decide_on_discard_support(struct drbd_device *device,
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 @@ static void sanitize_disk_conf(struct drbd_device *device, struct disk_conf *dis
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");
......
......@@ -828,7 +828,6 @@ static void loop_config_discard(struct loop_device *lo)
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 @@ static void loop_config_discard(struct loop_device *lo)
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);
}
......
......@@ -4025,7 +4025,6 @@ static int mtip_block_initialize(struct driver_data *dd)
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. */
......
......@@ -1110,7 +1110,6 @@ static int nbd_dev_add(int index)
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;
......
......@@ -2773,7 +2773,6 @@ static int cache_create(struct cache_args *ca, struct cache **result)
ti->num_discard_bios = 1;
ti->discards_supported = true;
ti->discard_zeroes_data_unsupported = true;
ti->split_discard_bios = false;
cache->features = ca->features;
......
......@@ -2030,7 +2030,6 @@ static int crypt_ctr(struct dm_target *ti, unsigned int argc, char **argv)
wake_up_process(cc->write_thread);
ti->num_flush_bios = 1;
ti->discard_zeroes_data_unsupported = true;
return 0;
......
......@@ -2813,7 +2813,9 @@ static void configure_discard_support(struct raid_set *rs)
/* 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 @@ static void configure_discard_support(struct raid_set *rs)
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.");
......
......@@ -1124,7 +1124,6 @@ static int mirror_ctr(struct dm_target *ti, unsigned int argc, char **argv)
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) {
......
......@@ -1449,22 +1449,6 @@ static bool dm_table_supports_flush(struct dm_table *t, unsigned long flush)
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 @@ void dm_table_set_restrictions(struct dm_table *t, struct request_queue *q,
}
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);
......
......@@ -3263,7 +3263,6 @@ static int pool_ctr(struct dm_target *ti, unsigned argc, char **argv)
* 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 @@ static int thin_ctr(struct dm_target *ti, unsigned argc, char **argv)
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;
......
......@@ -7227,7 +7227,6 @@ static int raid5_run(struct mddev *mddev)
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 @@ static int raid5_run(struct mddev *mddev)
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 @@ static int raid5_run(struct mddev *mddev)
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,
......
......@@ -644,8 +644,6 @@ static void sd_config_discard(struct scsi_disk *sdkp, unsigned int mode)
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 @@ static void sd_config_discard(struct scsi_disk *sdkp, unsigned int mode)
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;
}
......
......@@ -851,7 +851,7 @@ bool target_configure_unmap_from_queue(struct se_dev_attrib *attrib,
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);
......
......@@ -339,7 +339,6 @@ struct queue_limits {
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 @@ extern int blkdev_issue_write_same(struct block_device *bdev, sector_t sector,
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 @@ static inline int bdev_discard_alignment(struct block_device *bdev)
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);
......
......@@ -296,11 +296,6 @@ struct dm_target {
* 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 */
......
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