[PATCH v6 09/28] btrfs: align device extent allocation to zone boundary

Naohiro Aota
2019-12-13T04:10:59Z

In HMZONED mode, align 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, check that a region allocation
is always over empty zones and it is not over any locations of super block
zones.

This patch also add a verification in verify_one_dev_extent() to check if
the device extent is align to zone boundary.

Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
---
fs/btrfs/hmzoned.c | 55 ++++++++++++++++++++++++++++++++
fs/btrfs/hmzoned.h | 15 +++++++++
fs/btrfs/volumes.c | 78 ++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 148 insertions(+)

diff --git a/fs/btrfs/hmzoned.c b/fs/btrfs/hmzoned.c
index a74011650145..6263c8aee082 100644
--- a/fs/btrfs/hmzoned.c
+++ b/fs/btrfs/hmzoned.c
@@ -12,6 +12,7 @@
#include "volumes.h"
#include "hmzoned.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
@@ -550,3 +551,57 @@ int btrfs_reset_sb_log_zones(struct block_device *bdev, int mirror)
zone_sectors * 2,
GFP_NOFS);
}
+
+/*
+ * btrfs_check_allocatable_zones - check if spcecifeid region is
+ * suitable for allocation
+ * @device: the device to allocate a region
+ * @pos: the position of the region
+ * @num_bytes: the size of the region
+ *
+ * In non-ZONED device, anywhere is suitable for allocation. In ZONED
+ * device, check if
+ * 1) the region is not on non-empty sequential zones,
+ * 2) all zones in the region have the same zone type,
+ * 3) it does not contain super block location.
+ */
+bool btrfs_check_allocatable_zones(struct btrfs_device *device, u64 pos,
+ u64 num_bytes)
+{
+ struct btrfs_zoned_device_info *zinfo = device->zone_info;
+ u64 nzones, begin, end;
+ u64 sb_pos;
+ u8 shift;
+ int i;
+
+ if (!zinfo)
+ return true;
+
+ shift = zinfo->zone_size_shift;
+ nzones = num_bytes >> shift;
+ begin = pos >> shift;
+ end = begin + nzones;
+
+ ASSERT(IS_ALIGNED(pos, zinfo->zone_size));
+ ASSERT(IS_ALIGNED(num_bytes, zinfo->zone_size));
+
+ if (end > zinfo->nr_zones)
+ return false;
+
+ /* 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)
+ return false;
+
+ if (btrfs_dev_is_sequential(device, pos)) {
+ for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
+ sb_pos = sb_zone_number(zinfo->zone_size, i);
+ if (!(end < sb_pos || sb_pos + 1 < begin))
+ return false;
+ }
+
+ return find_next_zero_bit(zinfo->seq_zones, end, begin) == end;
+ }
+
+ return find_next_bit(zinfo->seq_zones, end, begin) == end;
+}
diff --git a/fs/btrfs/hmzoned.h b/fs/btrfs/hmzoned.h
index 55041a26ae3c..d54b4ae8cf8b 100644
--- a/fs/btrfs/hmzoned.h
+++ b/fs/btrfs/hmzoned.h
@@ -38,6 +38,8 @@ int btrfs_sb_log_location_bdev(struct block_device *bdev, int mirror, int rw,
u64 btrfs_sb_log_location(struct btrfs_device *device, int mirror, int rw);
int btrfs_advance_sb_log(struct btrfs_device *device, int mirror);
int btrfs_reset_sb_log_zones(struct block_device *bdev, int mirror);
+bool btrfs_check_allocatable_zones(struct btrfs_device *device, u64 pos,
+ u64 num_bytes);
#else /* CONFIG_BLK_DEV_ZONED */
static inline int btrfs_get_dev_zone(struct btrfs_device *device, u64 pos,
struct blk_zone *zone)
@@ -82,6 +84,11 @@ static inline int btrfs_reset_sb_log_zones(struct block_device *bdev,
{
return 0;
}
+static inline bool btrfs_check_allocatable_zones(struct btrfs_device *device,
+ u64 pos, u64 num_bytes)
+{
+ return true;
+}
#endif

static inline bool btrfs_dev_is_sequential(struct btrfs_device *device, u64 pos)
@@ -160,4 +167,12 @@ static inline bool btrfs_check_super_location(struct btrfs_device *device,
!btrfs_dev_is_sequential(device, pos);
}

+static inline u64 btrfs_zone_align(struct btrfs_device *device, u64 pos)
+{
+ if (!device->zone_info)
+ return pos;
+
+ return ALIGN(pos, device->zone_info->zone_size);
+}
+
#endif
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index a260648cecca..d5b280b59733 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -1393,6 +1393,7 @@ static int find_free_dev_extent_start(struct btrfs_device *device,
u64 max_hole_size;
u64 extent_end;
u64 search_end = device->total_bytes;
+ u64 zone_size = 0;
int ret;
int slot;
struct extent_buffer *l;
@@ -1403,6 +1404,15 @@ static int find_free_dev_extent_start(struct btrfs_device *device,
* at an offset of at least 1MB.
*/
search_start = max_t(u64, search_start, SZ_1M);
+ /*
+ * For a zoned block device, skip the first zone of the device
+ * entirely.
+ */
+ if (device->zone_info) {
+ zone_size = device->zone_info->zone_size;
+ search_start = max_t(u64, search_start, zone_size);
+ search_start = btrfs_zone_align(device, search_start);
+ }

path = btrfs_alloc_path();
if (!path)
@@ -1467,12 +1477,21 @@ static int find_free_dev_extent_start(struct btrfs_device *device,
*/
if (contains_pending_extent(device, &search_start,
hole_size)) {
+ search_start = btrfs_zone_align(device,
+ search_start);
if (key.offset >= search_start)
hole_size = key.offset - search_start;
else
hole_size = 0;
}

+ if (!btrfs_check_allocatable_zones(device, search_start,
+ num_bytes)) {
+ search_start += zone_size;
+ btrfs_release_path(path);
+ goto again;
+ }
+
if (hole_size > max_hole_size) {
max_hole_start = search_start;
max_hole_size = hole_size;
@@ -1512,6 +1531,14 @@ static int find_free_dev_extent_start(struct btrfs_device *device,
hole_size = search_end - search_start;

if (contains_pending_extent(device, &search_start, hole_size)) {
+ search_start = btrfs_zone_align(device, search_start);
+ btrfs_release_path(path);
+ goto again;
+ }
+
+ if (!btrfs_check_allocatable_zones(device, search_start,
+ num_bytes)) {
+ search_start += zone_size;
btrfs_release_path(path);
goto again;
}
@@ -1529,6 +1556,7 @@ static int find_free_dev_extent_start(struct btrfs_device *device,
ret = 0;

out:
+ ASSERT(zone_size == 0 || IS_ALIGNED(max_hole_start, zone_size));
btrfs_free_path(path);
*start = max_hole_start;
if (len)
@@ -4778,6 +4806,7 @@ static int __btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
int i;
int j;
int index;
+ bool hmzoned = btrfs_fs_incompat(info, HMZONED);

BUG_ON(!alloc_profile_is_valid(type, 0));

@@ -4819,10 +4848,25 @@ static int __btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
BUG();
}

+ if (hmzoned) {
+ max_stripe_size = info->zone_size;
+ max_chunk_size = round_down(max_chunk_size, info->zone_size);
+ }
+
/* We don't want a chunk larger than 10% of writable space */
max_chunk_size = min(div_factor(fs_devices->total_rw_bytes, 1),
max_chunk_size);

+ if (hmzoned) {
+ int min_num_stripes = devs_min * dev_stripes;
+ int min_data_stripes = (min_num_stripes - nparity) / ncopies;
+ u64 min_chunk_size = min_data_stripes * info->zone_size;
+
+ max_chunk_size = max(round_down(max_chunk_size,
+ info->zone_size),
+ min_chunk_size);
+ }
+
devices_info = kcalloc(fs_devices->rw_devices, sizeof(*devices_info),
GFP_NOFS);
if (!devices_info)
@@ -4857,6 +4901,9 @@ static int __btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
if (total_avail == 0)
continue;

+ if (hmzoned && total_avail < max_stripe_size * dev_stripes)
+ continue;
+
ret = find_free_dev_extent(device,
max_stripe_size * dev_stripes,
&dev_offset, &max_avail);
@@ -4875,6 +4922,9 @@ static int __btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
continue;
}

+ if (hmzoned && max_avail < max_stripe_size * dev_stripes)
+ continue;
+
if (ndevs == fs_devices->rw_devices) {
WARN(1, "%s: found more than %llu devices\n",
__func__, fs_devices->rw_devices);
@@ -4893,6 +4943,7 @@ static int __btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
sort(devices_info, ndevs, sizeof(struct btrfs_device_info),
btrfs_cmp_device_info, NULL);

+again:
/*
* Round down to number of usable stripes, devs_increment can be any
* number so we can't use round_down()
@@ -4934,6 +4985,17 @@ static int __btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
* we try to reduce stripe_size.
*/
if (stripe_size * data_stripes > max_chunk_size) {
+ if (hmzoned) {
+ /*
+ * stripe_size is fixed in HMZONED. Reduce ndevs
+ * instead.
+ */
+ ASSERT(nparity == 0);
+ ndevs = div_u64(max_chunk_size * ncopies,
+ stripe_size * dev_stripes);
+ goto again;
+ }
+
/*
* Reduce stripe_size, round it up to a 16MB boundary again and
* then use it, unless it ends up being even bigger than the
@@ -4947,6 +5009,8 @@ static int __btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
/* align to BTRFS_STRIPE_LEN */
stripe_size = round_down(stripe_size, BTRFS_STRIPE_LEN);

+ ASSERT(!hmzoned || stripe_size == info->zone_size);
+
map = kmalloc(map_lookup_size(num_stripes), GFP_NOFS);
if (!map) {
ret = -ENOMEM;
@@ -7541,6 +7605,20 @@ static int verify_one_dev_extent(struct btrfs_fs_info *fs_info,
ret = -EUCLEAN;
goto out;
}
+
+ if (dev->zone_info) {
+ u64 zone_size = dev->zone_info->zone_size;
+
+ if (!IS_ALIGNED(physical_offset, zone_size) ||
+ !IS_ALIGNED(physical_len, zone_size)) {
+ btrfs_err(fs_info,
+"dev extent devid %llu physical offset %llu len %llu is not aligned to device zone",
+ devid, physical_offset, physical_len);
+ ret = -EUCLEAN;
+ goto out;
+ }
+ }
+
out:
free_extent_map(em);
return ret;
--
2.24.0