This commit implements a zoned chunk/dev_extent allocator. The zoned
allocator aligns the device extents to zone boundaries, so that a zone
reset affects only the device extent and does not change the state of
blocks in the neighbor device extents.
Also, it checks that a region allocation is not overlapping any of the
super block zones, and ensures the region is empty.
Signed-off-by: Naohiro Aota <naohiro.aota@xxxxxxx>
---
fs/btrfs/volumes.c | 136 ++++++++++++++++++++++++++++++++++++++++++
fs/btrfs/volumes.h | 1 +
fs/btrfs/zoned.c | 144 +++++++++++++++++++++++++++++++++++++++++++++
fs/btrfs/zoned.h | 34 +++++++++++
4 files changed, 315 insertions(+)
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index db884b96a5ea..7831cf6c6da4 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -1416,6 +1416,21 @@ static bool contains_pending_extent(struct btrfs_device *device, u64 *start,
return false;
}
+static inline u64 dev_extent_search_start_zoned(struct btrfs_device *device,
+ u64 start)
+{
+ u64 tmp;
+
+ if (device->zone_info->zone_size > SZ_1M)
+ tmp = device->zone_info->zone_size;
+ else
+ tmp = SZ_1M;
+ if (start < tmp)
+ start = tmp;
+
+ return btrfs_align_offset_to_zone(device, start);
+}
+
static u64 dev_extent_search_start(struct btrfs_device *device, u64 start)
{
switch (device->fs_devices->chunk_alloc_policy) {
@@ -1426,11 +1441,57 @@ static u64 dev_extent_search_start(struct btrfs_device *device, u64 start)
* make sure to start at an offset of at least 1MB.
*/
return max_t(u64, start, SZ_1M);
+ case BTRFS_CHUNK_ALLOC_ZONED:
+ return dev_extent_search_start_zoned(device, start);
default:
BUG();
}
}
+static bool dev_extent_hole_check_zoned(struct btrfs_device *device,
+ u64 *hole_start, u64 *hole_size,
+ u64 num_bytes)
+{
+ u64 zone_size = device->zone_info->zone_size;
+ u64 pos;
+ int ret;
+ int changed = 0;
+
+ ASSERT(IS_ALIGNED(*hole_start, zone_size));
+
+ while (*hole_size > 0) {
+ pos = btrfs_find_allocatable_zones(device, *hole_start,
+ *hole_start + *hole_size,
+ num_bytes);
+ if (pos != *hole_start) {
+ *hole_size = *hole_start + *hole_size - pos;
+ *hole_start = pos;
+ changed = 1;
+ if (*hole_size < num_bytes)
+ break;
+ }
+
+ ret = btrfs_ensure_empty_zones(device, pos, num_bytes);
+
+ /* Range is ensured to be empty */
+ if (!ret)
+ return changed;
+
+ /* Given hole range was invalid (outside of device) */
+ if (ret == -ERANGE) {
+ *hole_start += *hole_size;
+ *hole_size = 0;
+ return 1;
+ }
+
+ *hole_start += zone_size;
+ *hole_size -= zone_size;
+ changed = 1;
+ }
+
+ return changed;
+}
+
/**
* dev_extent_hole_check - check if specified hole is suitable for allocation
* @device: the device which we have the hole
@@ -1463,6 +1524,10 @@ static bool dev_extent_hole_check(struct btrfs_device *device, u64 *hole_start,
case BTRFS_CHUNK_ALLOC_REGULAR:
/* No extra check */
break;
+ case BTRFS_CHUNK_ALLOC_ZONED:
+ changed |= dev_extent_hole_check_zoned(device, hole_start,
+ hole_size, num_bytes);
+ break;
default:
BUG();
}
@@ -1517,6 +1582,9 @@ static int find_free_dev_extent_start(struct btrfs_device *device,
search_start = dev_extent_search_start(device, search_start);
+ WARN_ON(device->zone_info &&
+ !IS_ALIGNED(num_bytes, device->zone_info->zone_size));
+
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
@@ -4907,6 +4975,37 @@ static void init_alloc_chunk_ctl_policy_regular(
ctl->dev_extent_min = BTRFS_STRIPE_LEN * ctl->dev_stripes;
}
+static void init_alloc_chunk_ctl_policy_zoned(
+ struct btrfs_fs_devices *fs_devices,
+ struct alloc_chunk_ctl *ctl)
+{
+ u64 zone_size = fs_devices->fs_info->zone_size;
+ u64 limit;
+ int min_num_stripes = ctl->devs_min * ctl->dev_stripes;
+ int min_data_stripes = (min_num_stripes - ctl->nparity) / ctl->ncopies;
+ u64 min_chunk_size = min_data_stripes * zone_size;
+ u64 type = ctl->type;
+
+ ctl->max_stripe_size = zone_size;
+ if (type & BTRFS_BLOCK_GROUP_DATA) {
+ ctl->max_chunk_size = round_down(BTRFS_MAX_DATA_CHUNK_SIZE,
+ zone_size);
+ } else if (type & BTRFS_BLOCK_GROUP_METADATA) {
+ ctl->max_chunk_size = ctl->max_stripe_size;
+ } else if (type & BTRFS_BLOCK_GROUP_SYSTEM) {
+ ctl->max_chunk_size = 2 * ctl->max_stripe_size;
+ ctl->devs_max = min_t(int, ctl->devs_max,
+ BTRFS_MAX_DEVS_SYS_CHUNK);
+ }
+
+ /* We don't want a chunk larger than 10% of writable space */
+ limit = max(round_down(div_factor(fs_devices->total_rw_bytes, 1),
+ zone_size),
+ min_chunk_size);
+ ctl->max_chunk_size = min(limit, ctl->max_chunk_size);
+ ctl->dev_extent_min = zone_size * ctl->dev_stripes;
+}
+
static void init_alloc_chunk_ctl(struct btrfs_fs_devices *fs_devices,
struct alloc_chunk_ctl *ctl)
{
@@ -4927,6 +5026,9 @@ static void init_alloc_chunk_ctl(struct btrfs_fs_devices *fs_devices,
case BTRFS_CHUNK_ALLOC_REGULAR:
init_alloc_chunk_ctl_policy_regular(fs_devices, ctl);
break;
+ case BTRFS_CHUNK_ALLOC_ZONED:
+ init_alloc_chunk_ctl_policy_zoned(fs_devices, ctl);
+ break;
default:
BUG();
}
@@ -5053,6 +5155,38 @@ static int decide_stripe_size_regular(struct alloc_chunk_ctl *ctl,
return 0;
}
+static int decide_stripe_size_zoned(struct alloc_chunk_ctl *ctl,
+ struct btrfs_device_info *devices_info)
+{
+ u64 zone_size = devices_info[0].dev->zone_info->zone_size;
+ /* Number of stripes that count for block group size */
+ int data_stripes;
+
+ /*
+ * It should hold because:
+ * dev_extent_min == dev_extent_want == zone_size * dev_stripes
+ */
+ ASSERT(devices_info[ctl->ndevs - 1].max_avail == ctl->dev_extent_min);
+
+ ctl->stripe_size = zone_size;
+ ctl->num_stripes = ctl->ndevs * ctl->dev_stripes;
+ data_stripes = (ctl->num_stripes - ctl->nparity) / ctl->ncopies;
+
+ /* stripe_size is fixed in ZONED. Reduce ndevs instead. */
+ if (ctl->stripe_size * data_stripes > ctl->max_chunk_size) {
+ ctl->ndevs = div_u64(div_u64(ctl->max_chunk_size * ctl->ncopies,
+ ctl->stripe_size) + ctl->nparity,
+ ctl->dev_stripes);
+ ctl->num_stripes = ctl->ndevs * ctl->dev_stripes;
+ data_stripes = (ctl->num_stripes - ctl->nparity) / ctl->ncopies;
+ ASSERT(ctl->stripe_size * data_stripes <= ctl->max_chunk_size);
+ }
+
+ ctl->chunk_size = ctl->stripe_size * data_stripes;
+
+ return 0;
+}
+
static int decide_stripe_size(struct btrfs_fs_devices *fs_devices,
struct alloc_chunk_ctl *ctl,
struct btrfs_device_info *devices_info)
@@ -5080,6 +5214,8 @@ static int decide_stripe_size(struct btrfs_fs_devices *fs_devices,
switch (fs_devices->chunk_alloc_policy) {
case BTRFS_CHUNK_ALLOC_REGULAR:
return decide_stripe_size_regular(ctl, devices_info);
+ case BTRFS_CHUNK_ALLOC_ZONED:
+ return decide_stripe_size_zoned(ctl, devices_info);
default:
BUG();
}
diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h
index 9c07b97a2260..0249aca668fb 100644
--- a/fs/btrfs/volumes.h
+++ b/fs/btrfs/volumes.h
@@ -213,6 +213,7 @@ BTRFS_DEVICE_GETSET_FUNCS(bytes_used);
enum btrfs_chunk_allocation_policy {
BTRFS_CHUNK_ALLOC_REGULAR,
+ BTRFS_CHUNK_ALLOC_ZONED,
};
struct btrfs_fs_devices {
diff --git a/fs/btrfs/zoned.c b/fs/btrfs/zoned.c
index 84ade8c19ddc..ed5de1c138d7 100644
--- a/fs/btrfs/zoned.c
+++ b/fs/btrfs/zoned.c
@@ -1,11 +1,13 @@
// SPDX-License-Identifier: GPL-2.0
+#include <linux/bitops.h>
#include <linux/slab.h>
#include <linux/blkdev.h>
#include "ctree.h"
#include "volumes.h"
#include "zoned.h"
#include "rcu-string.h"
+#include "disk-io.h"
/* Maximum number of zones to report per blkdev_report_zones() call */
#define BTRFS_REPORT_NR_ZONES 4096
@@ -424,6 +426,7 @@ int btrfs_check_zoned_mode(struct btrfs_fs_info *fs_info)
fs_info->zone_size = zone_size;
fs_info->max_zone_append_size = max_zone_append_size;
+ fs_info->fs_devices->chunk_alloc_policy = BTRFS_CHUNK_ALLOC_ZONED;
btrfs_info(fs_info, "zoned mode enabled with zone size %llu",
fs_info->zone_size);
@@ -633,3 +636,144 @@ int btrfs_reset_sb_log_zones(struct block_device *bdev, int mirror)
sb_zone << zone_sectors_shift,
zone_sectors * BTRFS_NR_SB_LOG_ZONES, GFP_NOFS);
}
+
+/*
+ * btrfs_check_allocatable_zones - find allocatable zones within give region
+ * @device: the device to allocate a region
+ * @hole_start: the position of the hole to allocate the region
+ * @num_bytes: the size of wanted region
+ * @hole_size: the size of hole
+ *
+ * Allocatable region should not contain any superblock locations.
+ */
+u64 btrfs_find_allocatable_zones(struct btrfs_device *device, u64 hole_start,
+ u64 hole_end, u64 num_bytes)
+{
+ struct btrfs_zoned_device_info *zinfo = device->zone_info;
+ u8 shift = zinfo->zone_size_shift;
+ u64 nzones = num_bytes >> shift;
+ u64 pos = hole_start;
+ u64 begin, end;
+ bool have_sb;
+ int i;
+
+ ASSERT(IS_ALIGNED(hole_start, zinfo->zone_size));
+ ASSERT(IS_ALIGNED(num_bytes, zinfo->zone_size));
+
+ while (pos < hole_end) {
+ begin = pos >> shift;
+ end = begin + nzones;
+
+ if (end > zinfo->nr_zones)
+ return hole_end;
+
+ /* Check if zones in the region are all empty */
+ if (btrfs_dev_is_sequential(device, pos) &&
+ find_next_zero_bit(zinfo->empty_zones, end, begin) != end) {
+ pos += zinfo->zone_size;
+ continue;
+ }
+
+ have_sb = false;
+ for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
+ u32 sb_zone;
+ u64 sb_pos;
+
+ sb_zone = sb_zone_number(shift, i);
+ if (!(end <= sb_zone ||
+ sb_zone + BTRFS_NR_SB_LOG_ZONES <= begin)) {
+ have_sb = true;
+ pos = ((u64)sb_zone + BTRFS_NR_SB_LOG_ZONES) << shift;
+ break;
+ }
+
+ /*
+ * We also need to exclude regular superblock
+ * positions
+ */
+ sb_pos = btrfs_sb_offset(i);
+ if (!(pos + num_bytes <= sb_pos ||
+ sb_pos + BTRFS_SUPER_INFO_SIZE <= pos)) {
+ have_sb = true;
+ pos = ALIGN(sb_pos + BTRFS_SUPER_INFO_SIZE,
+ zinfo->zone_size);
+ break;
+ }
+ }
+ if (!have_sb)
+ break;
+
+ }
+
+ return pos;
+}
+
+int btrfs_reset_device_zone(struct btrfs_device *device, u64 physical,
+ u64 length, u64 *bytes)
+{
+ int ret;
+
+ *bytes = 0;
+ ret = blkdev_zone_mgmt(device->bdev, REQ_OP_ZONE_RESET,
+ physical >> SECTOR_SHIFT, length >> SECTOR_SHIFT,
+ GFP_NOFS);
+ if (ret)
+ return ret;
+
+ *bytes = length;
+ while (length) {
+ btrfs_dev_set_zone_empty(device, physical);
+ physical += device->zone_info->zone_size;
+ length -= device->zone_info->zone_size;
+ }
+
+ return 0;
+}
+
+int btrfs_ensure_empty_zones(struct btrfs_device *device, u64 start, u64 size)
+{
+ struct btrfs_zoned_device_info *zinfo = device->zone_info;
+ u8 shift = zinfo->zone_size_shift;
+ unsigned long begin = start >> shift;
+ unsigned long end = (start + size) >> shift;
+ u64 pos;
+ int ret;
+
+ ASSERT(IS_ALIGNED(start, zinfo->zone_size));
+ ASSERT(IS_ALIGNED(size, zinfo->zone_size));
+
+ if (end > zinfo->nr_zones)
+ return -ERANGE;
+
+ /* All the zones are conventional */
+ if (find_next_bit(zinfo->seq_zones, begin, end) == end)
+ return 0;
+
+ /* All the zones are sequential and empty */
+ if (find_next_zero_bit(zinfo->seq_zones, begin, end) == end &&
+ find_next_zero_bit(zinfo->empty_zones, begin, end) == end)
+ return 0;
+
+ for (pos = start; pos < start + size; pos += zinfo->zone_size) {
+ u64 reset_bytes;
+
+ if (!btrfs_dev_is_sequential(device, pos) ||
+ btrfs_dev_is_empty_zone(device, pos))
+ continue;
+
+ /* Free regions should be empty */
+ btrfs_warn_in_rcu(
+ device->fs_info,
+ "zoned: resetting device %s (devid %llu) zone %llu for allocation",
+ rcu_str_deref(device->name), device->devid,
+ pos >> shift);
+ WARN_ON_ONCE(1);
+
+ ret = btrfs_reset_device_zone(device, pos, zinfo->zone_size,
+ &reset_bytes);
+ if (ret)
+ return ret;
+ }
+
+ return 0;
+}
diff --git a/fs/btrfs/zoned.h b/fs/btrfs/zoned.h
index de9d7dd8c351..ec2391c52d8b 100644
--- a/fs/btrfs/zoned.h
+++ b/fs/btrfs/zoned.h
@@ -35,6 +35,11 @@ int btrfs_sb_log_location(struct btrfs_device *device, int mirror, int rw,
u64 *bytenr_ret);
void btrfs_advance_sb_log(struct btrfs_device *device, int mirror);
int btrfs_reset_sb_log_zones(struct block_device *bdev, int mirror);
+u64 btrfs_find_allocatable_zones(struct btrfs_device *device, u64 hole_start,
+ u64 hole_end, u64 num_bytes);
+int btrfs_reset_device_zone(struct btrfs_device *device, u64 physical,
+ u64 length, u64 *bytes);
+int btrfs_ensure_empty_zones(struct btrfs_device *device, u64 start, u64 size);
#else /* CONFIG_BLK_DEV_ZONED */
static inline int btrfs_get_dev_zone(struct btrfs_device *device, u64 pos,
struct blk_zone *zone)
@@ -87,6 +92,26 @@ static inline int btrfs_reset_sb_log_zones(struct block_device *bdev,
return 0;
}
+static inline u64 btrfs_find_allocatable_zones(struct btrfs_device *device,
+ u64 hole_start, u64 hole_end,
+ u64 num_bytes)
+{
+ return hole_start;
+}
+
+static inline int btrfs_reset_device_zone(struct btrfs_device *device,
+ u64 physical, u64 length, u64 *bytes)
+{
+ *bytes = 0;
+ return 0;
+}
+
+static inline int btrfs_ensure_empty_zones(struct btrfs_device *device,
+ u64 start, u64 size)
+{
+ return 0;
+}
+
#endif
static inline bool btrfs_dev_is_sequential(struct btrfs_device *device, u64 pos)
@@ -165,4 +190,13 @@ static inline bool btrfs_check_super_location(struct btrfs_device *device,
!btrfs_dev_is_sequential(device, pos);
}
+static inline u64 btrfs_align_offset_to_zone(struct btrfs_device *device,
+ u64 pos)
+{
+ if (!device->zone_info)
+ return pos;
+
+ return ALIGN(pos, device->zone_info->zone_size);
+}
+
#endif
--
2.27.0
