If the backing device is a zoned device, e.g. host managed SMR hard
drive, the data_offset of the backing device should be set to a zone
size aligned value, this is necessary for the zoned device I/O LBA
and length requirement.
This patch set the data_offset for zoned backing device by following
rules,
- If no manually inputed data_offset specified, set it to default
value:
- If BDEV_DATA_START_DEFAULT >= zone size and aligned to zone size,
keep data_offset as BDEV_DATA_START_DEFAULT.
- If BDEV_DATA_START_DEFAULT < zone size, set data_offset to zone
size.
- If data_offset is manually set, it must be a non-zero value aligned
to zone size. Of cause it can be multiple zones size, but must be
aligned to zone size.
This patch also creates a new zone.c and zone.h and places all the
above zoned device related code there.
Signed-off-by: Coly Li <colyli@xxxxxxx>
---
Makefile | 4 +--
make.c | 7 ++++-
zoned.c | 89 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
zoned.h | 13 +++++++++
4 files changed, 110 insertions(+), 3 deletions(-)
create mode 100644 zoned.c
create mode 100644 zoned.h
diff --git a/Makefile b/Makefile
index 4359866..2c326cf 100644
--- a/Makefile
+++ b/Makefile
@@ -24,7 +24,7 @@ bcache-test: LDLIBS += `pkg-config --libs openssl` -lm
make-bcache: LDLIBS += `pkg-config --libs uuid blkid smartcols`
make-bcache: CFLAGS += `pkg-config --cflags uuid blkid smartcols`
-make-bcache: make.o crc64.o lib.o
+make-bcache: make.o crc64.o lib.o zoned.o
probe-bcache: LDLIBS += `pkg-config --libs uuid blkid`
probe-bcache: CFLAGS += `pkg-config --cflags uuid blkid`
@@ -38,4 +38,4 @@ bcache-register: bcache-register.o
bcache: CFLAGS += `pkg-config --cflags blkid uuid smartcols`
bcache: LDLIBS += `pkg-config --libs blkid uuid smartcols`
bcache: CFLAGS += -std=gnu99
-bcache: crc64.o lib.o make.o
+bcache: crc64.o lib.o make.o zoned.o
diff --git a/make.c b/make.c
index d46d925..c1090a6 100644
--- a/make.c
+++ b/make.c
@@ -35,6 +35,7 @@
#include "bcache.h"
#include "lib.h"
#include "bitwise.h"
+#include "zoned.h"
#define max(x, y) ({ \
typeof(x) _max1 = (x); \
@@ -636,11 +637,15 @@ int make_bcache(int argc, char **argv)
cache_replacement_policy,
data_offset, set_uuid, false, force, label);
- for (i = 0; i < nbacking_devices; i++)
+ for (i = 0; i < nbacking_devices; i++) {
+ check_data_offset_for_zoned_device(backing_devices[i],
+ &data_offset);
+
write_sb(backing_devices[i], block_size, bucket_size,
writeback, discard, wipe_bcache,
cache_replacement_policy,
data_offset, set_uuid, true, force, label);
+ }
return 0;
}
diff --git a/zoned.c b/zoned.c
new file mode 100644
index 0000000..31c9136
--- /dev/null
+++ b/zoned.c
@@ -0,0 +1,89 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * This file is part of bcache tools.
+ * Copyright (c) 2020 SUSE Software Solutions
+ *
+ * Authors: Coly Li <colyli@xxxxxxx>
+ */
+
+#include <errno.h>
+#include <stdbool.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <libgen.h>
+
+#include "bcache.h"
+
+/*
+ * copied and modified from zonefs_get_dev_capacity() of
+ * zonefs-tools.
+ * returns 0: zone size 0 indicates a non-zoned device
+ * > 0: actual zone size of the zoned device
+ */
+static size_t get_zone_size(char *devname)
+{
+ char str[128];
+ FILE *file;
+ int res;
+ size_t zone_size = 0;
+
+ snprintf(str, sizeof(str),
+ "/sys/block/%s/queue/chunk_sectors",
+ basename(devname));
+ file = fopen(str, "r");
+ if (!file)
+ goto out;
+
+ memset(str, 0, sizeof(str));
+ res = fscanf(file, "%s", str);
+ fclose(file);
+
+ if (res != 1)
+ goto out;
+
+ zone_size = atol(str);
+
+out:
+ return zone_size;
+}
+
+/*
+ * Update data_offset for zoned device, if the backing
+ * device is a zoned device,
+ * - just leave whole zone 0 to bcache super block on
+ * backing device.
+ * - if data_offset is specified and larger than
+ * BDEV_DATA_START_DEFAULT, then it should be a zone
+ * size aligned value.
+ */
+void check_data_offset_for_zoned_device(char *devname,
+ uint64_t *data_offset)
+{
+ uint64_t _data_offset = *data_offset;
+ size_t zone_size = get_zone_size(devname);
+
+ if (!zone_size)
+ return;
+
+ if (!_data_offset ||
+ (_data_offset == BDEV_DATA_START_DEFAULT &&
+ zone_size > BDEV_DATA_START_DEFAULT))
+ _data_offset = zone_size;
+
+ if (_data_offset < zone_size) {
+ fprintf(stderr,
+ "data_offset %lu should be larger than zone_size %lu for zoned device %s\n",
+ _data_offset, zone_size, devname);
+ exit(EXIT_FAILURE);
+ }
+
+ if (_data_offset & (zone_size - 1)) {
+ fprintf(stderr,
+ "data_offset %lu is not aligned to zone size %lu for zoned device %s\n",
+ _data_offset, zone_size, devname);
+ }
+
+ *data_offset = _data_offset;
+}
diff --git a/zoned.h b/zoned.h
new file mode 100644
index 0000000..1c5cce8
--- /dev/null
+++ b/zoned.h
@@ -0,0 +1,13 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * This file is part of bcache tools.
+ * Copyright (c) 2020 SUSE Software Solutions
+ *
+ * Authors: Coly Li <colyli@xxxxxxx>
+ */
+#ifndef __ZONED_H
+#define __ZONED_H
+
+void check_data_offset_for_zoned_device(char *devname, uint64_t *data_offset);
+
+#endif
--
2.25.0
