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-rw-r--r--Makefile2
-rw-r--r--file.h12
-rw-r--r--filesetup.c21
-rw-r--r--io_ddir.h2
-rw-r--r--io_u.c176
-rw-r--r--lib/bitmap.c382
-rw-r--r--lib/bitmap.h18
7 files changed, 443 insertions, 170 deletions
diff --git a/Makefile b/Makefile
index b68ab061..70309147 100644
--- a/Makefile
+++ b/Makefile
@@ -17,7 +17,7 @@ SOURCE := gettime.c fio.c ioengines.c init.c stat.c log.c time.c filesetup.c \
lib/num2str.c lib/ieee754.c $(wildcard crc/*.c) engines/cpu.c \
engines/mmap.c engines/sync.c engines/null.c engines/net.c \
memalign.c server.c client.c iolog.c backend.c libfio.c flow.c \
- json.c lib/zipf.c gettime-thread.c
+ json.c lib/zipf.c lib/bitmap.c gettime-thread.c
ifeq ($(UNAME), Linux)
SOURCE += diskutil.c fifo.c blktrace.c helpers.c cgroup.c trim.c \
diff --git a/file.h b/file.h
index 38e9d0d4..ce92ff75 100644
--- a/file.h
+++ b/file.h
@@ -6,6 +6,7 @@
#include "io_ddir.h"
#include "flist.h"
#include "lib/zipf.h"
+#include "lib/bitmap.h"
/*
* The type of object we are working on
@@ -108,10 +109,7 @@ struct fio_file {
/*
* block map for random io
*/
- unsigned long *file_map;
- unsigned long num_maps;
- unsigned long last_free_lookup;
- unsigned failed_rands;
+ struct bitmap *io_bitmap;
/*
* Used for zipf random distribution
@@ -177,13 +175,11 @@ extern void free_release_files(struct thread_data *);
static inline void fio_file_reset(struct fio_file *f)
{
- f->last_free_lookup = 0;
- f->failed_rands = 0;
f->last_pos = f->file_offset;
f->last_start = -1ULL;
f->file_pos = -1ULL;
- if (f->file_map)
- memset(f->file_map, 0, f->num_maps * sizeof(unsigned long));
+ if (f->io_bitmap)
+ bitmap_reset(f->io_bitmap);
}
#endif
diff --git a/filesetup.c b/filesetup.c
index c488eb47..c96c2502 100644
--- a/filesetup.c
+++ b/filesetup.c
@@ -13,6 +13,7 @@
#include "filehash.h"
#include "os/os.h"
#include "hash.h"
+#include "lib/bitmap.h"
#ifdef FIO_HAVE_LINUX_FALLOCATE
#include <linux/falloc.h>
@@ -904,7 +905,7 @@ static int init_rand_distribution(struct thread_data *td)
int init_random_map(struct thread_data *td)
{
- unsigned long long blocks, num_maps;
+ unsigned long long blocks;
struct fio_file *f;
unsigned int i;
@@ -916,16 +917,9 @@ int init_random_map(struct thread_data *td)
for_each_file(td, f, i) {
blocks = (f->real_file_size + td->o.rw_min_bs - 1) /
(unsigned long long) td->o.rw_min_bs;
- num_maps = (blocks + BLOCKS_PER_MAP - 1) /
- (unsigned long long) BLOCKS_PER_MAP;
- if (num_maps == (unsigned long) num_maps) {
- f->file_map = smalloc(num_maps * sizeof(unsigned long));
- if (f->file_map) {
- f->num_maps = num_maps;
- continue;
- }
- } else
- f->file_map = NULL;
+ f->io_bitmap = bitmap_new(blocks);
+ if (f->io_bitmap)
+ continue;
if (!td->o.softrandommap) {
log_err("fio: failed allocating random map. If running"
@@ -937,7 +931,6 @@ int init_random_map(struct thread_data *td)
log_info("fio: file %s failed allocating random map. Running "
"job without.\n", f->file_name);
- f->num_maps = 0;
}
return 0;
@@ -974,8 +967,8 @@ void close_and_free_files(struct thread_data *td)
sfree(f->file_name);
f->file_name = NULL;
- sfree(f->file_map);
- f->file_map = NULL;
+ bitmap_free(f->io_bitmap);
+ f->io_bitmap = NULL;
sfree(f);
}
diff --git a/io_ddir.h b/io_ddir.h
index df5abbbc..d13c6b1e 100644
--- a/io_ddir.h
+++ b/io_ddir.h
@@ -30,7 +30,7 @@ enum td_ddir {
#define td_trim(td) ((td)->o.td_ddir & TD_DDIR_TRIM)
#define td_rw(td) (((td)->o.td_ddir & TD_DDIR_RW) == TD_DDIR_RW)
#define td_random(td) ((td)->o.td_ddir & TD_DDIR_RAND)
-#define file_randommap(td, f) (!(td)->o.norandommap && (f)->file_map)
+#define file_randommap(td, f) (!(td)->o.norandommap && (f)->io_bitmap)
static inline int ddir_sync(enum fio_ddir ddir)
{
diff --git a/io_u.c b/io_u.c
index d81fefde..d6816068 100644
--- a/io_u.c
+++ b/io_u.c
@@ -10,6 +10,7 @@
#include "verify.h"
#include "trim.h"
#include "lib/rand.h"
+#include "lib/bitmap.h"
struct io_completion_data {
int nr; /* input */
@@ -20,17 +21,12 @@ struct io_completion_data {
};
/*
- * The ->file_map[] contains a map of blocks we have or have not done io
+ * The ->io_bitmap contains a map of blocks we have or have not done io
* to yet. Used to make sure we cover the entire range in a fair fashion.
*/
static int random_map_free(struct fio_file *f, const unsigned long long block)
{
- unsigned int idx = RAND_MAP_IDX(f, block);
- unsigned int bit = RAND_MAP_BIT(f, block);
-
- dprint(FD_RANDOM, "free: b=%llu, idx=%u, bit=%u\n", block, idx, bit);
-
- return (f->file_map[idx] & (1UL << bit)) == 0;
+ return !bitmap_isset(f->io_bitmap, block);
}
/*
@@ -41,61 +37,15 @@ static void mark_random_map(struct thread_data *td, struct io_u *io_u)
unsigned int min_bs = td->o.rw_min_bs;
struct fio_file *f = io_u->file;
unsigned long long block;
- unsigned int blocks, nr_blocks;
- int busy_check;
+ unsigned int nr_blocks;
block = (io_u->offset - f->file_offset) / (unsigned long long) min_bs;
nr_blocks = (io_u->buflen + min_bs - 1) / min_bs;
- blocks = 0;
- busy_check = !(io_u->flags & IO_U_F_BUSY_OK);
-
- while (nr_blocks) {
- unsigned int idx, bit;
- unsigned long mask, this_blocks;
-
- /*
- * If we have a mixed random workload, we may
- * encounter blocks we already did IO to.
- */
- if (!busy_check) {
- blocks = nr_blocks;
- break;
- }
- if ((td->o.ddir_seq_nr == 1) && !random_map_free(f, block))
- break;
-
- idx = RAND_MAP_IDX(f, block);
- bit = RAND_MAP_BIT(f, block);
-
- fio_assert(td, idx < f->num_maps);
-
- this_blocks = nr_blocks;
- if (this_blocks + bit > BLOCKS_PER_MAP)
- this_blocks = BLOCKS_PER_MAP - bit;
-
- do {
- if (this_blocks == BLOCKS_PER_MAP)
- mask = -1UL;
- else
- mask = ((1UL << this_blocks) - 1) << bit;
-
- if (!(f->file_map[idx] & mask))
- break;
- this_blocks--;
- } while (this_blocks);
+ nr_blocks = bitmap_set_nr(f->io_bitmap, block, nr_blocks);
- if (!this_blocks)
- break;
-
- f->file_map[idx] |= mask;
- nr_blocks -= this_blocks;
- blocks += this_blocks;
- block += this_blocks;
- }
-
- if ((blocks * min_bs) < io_u->buflen)
- io_u->buflen = blocks * min_bs;
+ if ((nr_blocks * min_bs) < io_u->buflen)
+ io_u->buflen = nr_blocks * min_bs;
}
static unsigned long long last_block(struct thread_data *td, struct fio_file *f,
@@ -123,113 +73,46 @@ static unsigned long long last_block(struct thread_data *td, struct fio_file *f,
return max_blocks;
}
-/*
- * Return the next free block in the map.
- */
-static int get_next_free_block(struct thread_data *td, struct fio_file *f,
- enum fio_ddir ddir, unsigned long long *b)
-{
- unsigned long long block, min_bs = td->o.rw_min_bs, lastb;
- int i;
-
- lastb = last_block(td, f, ddir);
- if (!lastb)
- return 1;
-
- i = f->last_free_lookup;
- block = i * BLOCKS_PER_MAP;
- while (block * min_bs < f->real_file_size &&
- block * min_bs < f->io_size) {
- if (f->file_map[i] != -1UL) {
- block += ffz(f->file_map[i]);
- if (block > lastb)
- break;
- f->last_free_lookup = i;
- *b = block;
- return 0;
- }
-
- block += BLOCKS_PER_MAP;
- i++;
- }
-
- dprint(FD_IO, "failed finding a free block\n");
- return 1;
-}
-
static int __get_next_rand_offset(struct thread_data *td, struct fio_file *f,
enum fio_ddir ddir, unsigned long long *b)
{
unsigned long long rmax, r, lastb;
- int loops = 5;
lastb = last_block(td, f, ddir);
if (!lastb)
return 1;
- if (f->failed_rands >= 200)
- goto ffz;
-
rmax = td->o.use_os_rand ? OS_RAND_MAX : FRAND_MAX;
- do {
- if (td->o.use_os_rand)
- r = os_random_long(&td->random_state);
- else
- r = __rand(&td->__random_state);
-
- *b = (lastb - 1) * (r / ((unsigned long long) rmax + 1.0));
-
- dprint(FD_RANDOM, "off rand %llu\n", r);
-
-
- /*
- * if we are not maintaining a random map, we are done.
- */
- if (!file_randommap(td, f))
- goto ret_good;
- /*
- * calculate map offset and check if it's free
- */
- if (random_map_free(f, *b))
- goto ret_good;
+ if (td->o.use_os_rand) {
+ rmax = OS_RAND_MAX;
+ r = os_random_long(&td->random_state);
+ } else {
+ rmax = FRAND_MAX;
+ r = __rand(&td->__random_state);
+ }
- dprint(FD_RANDOM, "get_next_rand_offset: offset %llu busy\n",
- *b);
- } while (--loops);
+ *b = (lastb - 1) * (r / ((unsigned long long) rmax + 1.0));
- if (!f->failed_rands++)
- f->last_free_lookup = 0;
+ dprint(FD_RANDOM, "off rand %llu\n", r);
/*
- * we get here, if we didn't suceed in looking up a block. generate
- * a random start offset into the filemap, and find the first free
- * block from there.
+ * if we are not maintaining a random map, we are done.
*/
- loops = 10;
- do {
- f->last_free_lookup = (f->num_maps - 1) *
- (r / ((unsigned long long) rmax + 1.0));
- if (!get_next_free_block(td, f, ddir, b))
- goto ret;
-
- if (td->o.use_os_rand)
- r = os_random_long(&td->random_state);
- else
- r = __rand(&td->__random_state);
- } while (--loops);
+ if (!file_randommap(td, f))
+ goto ret;
/*
- * that didn't work either, try exhaustive search from the start
+ * calculate map offset and check if it's free
*/
- f->last_free_lookup = 0;
-ffz:
- if (!get_next_free_block(td, f, ddir, b))
- return 0;
- f->last_free_lookup = 0;
- return get_next_free_block(td, f, ddir, b);
-ret_good:
- f->failed_rands = 0;
+ if (random_map_free(f, *b))
+ goto ret;
+
+ dprint(FD_RANDOM, "get_next_rand_offset: offset %llu busy\n", *b);
+
+ *b = bitmap_next_free(f->io_bitmap, *b);
+ if (*b == (uint64_t) -1ULL)
+ return 1;
ret:
return 0;
}
@@ -347,7 +230,8 @@ static int get_next_block(struct thread_data *td, struct io_u *io_u,
else if (b != -1ULL)
io_u->offset = b * td->o.ba[ddir];
else {
- log_err("fio: bug in offset generation\n");
+ log_err("fio: bug in offset generation: offset=%llu, b=%llu\n",
+ offset, b);
ret = 1;
}
}
diff --git a/lib/bitmap.c b/lib/bitmap.c
new file mode 100644
index 00000000..a88b680c
--- /dev/null
+++ b/lib/bitmap.c
@@ -0,0 +1,382 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <assert.h>
+
+#include "../arch/arch.h"
+#include "bitmap.h"
+#include "../smalloc.h"
+#include "../minmax.h"
+
+#if BITS_PER_LONG == 64
+#define UNIT_SIZE 8
+#define UNIT_SHIFT 6
+#elif BITS_PER_LONG == 32
+#define UNIT_SIZE 4
+#define UNIT_SHIFT 5
+#else
+#error "Number of arch bits unknown"
+#endif
+
+#define BLOCKS_PER_UNIT (1UL << UNIT_SHIFT)
+#define BLOCKS_PER_UNIT_MASK (BLOCKS_PER_UNIT - 1)
+
+#define firstfree_valid(b) ((b)->first_free != (uint64_t) -1)
+
+struct bitmap_level {
+ int level;
+ unsigned long map_size;
+ unsigned long *map;
+};
+
+struct bitmap {
+ unsigned int nr_levels;
+ struct bitmap_level *levels;
+ uint64_t first_free;
+};
+
+static unsigned long ulog64(unsigned long val, unsigned int log)
+{
+ while (log-- && val)
+ val >>= UNIT_SHIFT;
+
+ return val;
+}
+
+void bitmap_reset(struct bitmap *bitmap)
+{
+ int i;
+
+ for (i = 0; i < bitmap->nr_levels; i++) {
+ struct bitmap_level *bl = &bitmap->levels[i];
+
+ memset(bl->map, 0, bl->map_size * UNIT_SIZE);
+ }
+}
+
+void bitmap_free(struct bitmap *bitmap)
+{
+ unsigned int i;
+
+ if (!bitmap)
+ return;
+
+ for (i = 0; i < bitmap->nr_levels; i++) {
+#if 0
+ unsigned long j;
+
+ for (j = 0; j < bitmap->levels[i].map_size; j++) {
+ if (bitmap->levels[i].map[j] != ~0UL)
+ printf("L%d: %.5ld=%.16lx\n", i, j, bitmap->levels[i].map[j]);
+ }
+#endif
+
+ sfree(bitmap->levels[i].map);
+ }
+
+ sfree(bitmap->levels);
+ sfree(bitmap);
+}
+
+struct bitmap *bitmap_new(unsigned long nr_bits)
+{
+ struct bitmap *bitmap;
+ unsigned int i, levels;
+
+ bitmap = smalloc(sizeof(*bitmap));
+ if (!bitmap)
+ return NULL;
+
+ levels = 1;
+ i = (nr_bits + BLOCKS_PER_UNIT - 1) >> UNIT_SHIFT;
+ while (i > 1) {
+ i = (i + BLOCKS_PER_UNIT - 1) >> UNIT_SHIFT;
+ levels++;
+ }
+
+ bitmap->nr_levels = levels;
+ bitmap->levels = smalloc(bitmap->nr_levels * sizeof(struct bitmap_level));
+ bitmap->first_free = 0;
+
+ for (i = 0; i < bitmap->nr_levels; i++) {
+ struct bitmap_level *bl = &bitmap->levels[i];
+
+ bl->level = i;
+ bl->map_size = (nr_bits + BLOCKS_PER_UNIT - 1) >> UNIT_SHIFT;
+ bl->map = smalloc(bl->map_size << UNIT_SHIFT);
+ if (!bl->map)
+ goto err;
+
+ nr_bits = (nr_bits + BLOCKS_PER_UNIT - 1) >> UNIT_SHIFT;
+ }
+
+ bitmap_reset(bitmap);
+ return bitmap;
+err:
+ for (i = 0; i < bitmap->nr_levels; i++)
+ if (bitmap->levels[i].map)
+ sfree(bitmap->levels[i].map);
+
+ sfree(bitmap->levels);
+ return NULL;
+}
+
+static int bitmap_handler(struct bitmap *bitmap, uint64_t bit_nr,
+ int (*func)(struct bitmap_level *, unsigned long, unsigned int,
+ void *), void *data)
+{
+ struct bitmap_level *bl;
+ int i;
+
+ for (i = 0; i < bitmap->nr_levels; i++) {
+ unsigned long index = ulog64(bit_nr, i);
+ unsigned long offset = index >> UNIT_SHIFT;
+ unsigned int bit = index & BLOCKS_PER_UNIT_MASK;
+
+ bl = &bitmap->levels[i];
+
+ if (func(bl, offset, bit, data))
+ return 1;
+ }
+
+ return 0;
+}
+
+static int bitmap_handler_topdown(struct bitmap *bitmap, uint64_t bit_nr,
+ int (*func)(struct bitmap_level *, unsigned long, unsigned int, void *),
+ void *data)
+{
+ struct bitmap_level *bl;
+ int i, level = bitmap->nr_levels;
+
+ for (i = bitmap->nr_levels - 1; i >= 0; i--) {
+ unsigned long index = ulog64(bit_nr, --level);
+ unsigned long offset = index >> UNIT_SHIFT;
+ unsigned int bit = index & BLOCKS_PER_UNIT_MASK;
+
+ bl = &bitmap->levels[i];
+
+ if (func(bl, offset, bit, data))
+ return 1;
+ }
+
+ return 0;
+}
+
+static int bitmap_clear_fn(struct bitmap_level *bl, unsigned long offset,
+ unsigned int bit, void *unused)
+{
+ if (!(bl->map[offset] & (1UL << bit)))
+ return 1;
+
+ bl->map[offset] &= ~(1UL << bit);
+ return 0;
+}
+
+void bitmap_clear(struct bitmap *bitmap, uint64_t bit_nr)
+{
+ bitmap_handler(bitmap, bit_nr, bitmap_clear_fn, NULL);
+}
+
+struct bitmap_set_data {
+ unsigned int nr_bits;
+ unsigned int set_bits;
+ unsigned int fail_ok;
+};
+
+static unsigned long bit_masks[] = {
+ 0x0000000000000000, 0x0000000000000001, 0x0000000000000003, 0x0000000000000007,
+ 0x000000000000000f, 0x000000000000001f, 0x000000000000003f, 0x000000000000007f,
+ 0x00000000000000ff, 0x00000000000001ff, 0x00000000000003ff, 0x00000000000007ff,
+ 0x0000000000000fff, 0x0000000000001fff, 0x0000000000003fff, 0x0000000000007fff,
+ 0x000000000000ffff, 0x000000000001ffff, 0x000000000003ffff, 0x000000000007ffff,
+ 0x00000000000fffff, 0x00000000001fffff, 0x00000000003fffff, 0x00000000007fffff,
+ 0x0000000000ffffff, 0x0000000001ffffff, 0x0000000003ffffff, 0x0000000007ffffff,
+ 0x000000000fffffff, 0x000000001fffffff, 0x000000003fffffff, 0x000000007fffffff,
+ 0x00000000ffffffff, 0x00000001ffffffff, 0x00000003ffffffff, 0x00000007ffffffff,
+ 0x0000000fffffffff, 0x0000001fffffffff, 0x0000003fffffffff, 0x0000007fffffffff,
+ 0x000000ffffffffff, 0x000001ffffffffff, 0x000003ffffffffff, 0x000007ffffffffff,
+ 0x00000fffffffffff, 0x00001fffffffffff, 0x00003fffffffffff, 0x00007fffffffffff,
+ 0x0000ffffffffffff, 0x0001ffffffffffff, 0x0003ffffffffffff, 0x0007ffffffffffff,
+ 0x000fffffffffffff, 0x001fffffffffffff, 0x003fffffffffffff, 0x007fffffffffffff,
+ 0x00ffffffffffffff, 0x01ffffffffffffff, 0x03ffffffffffffff, 0x07ffffffffffffff,
+ 0x0fffffffffffffff, 0x1fffffffffffffff, 0x3fffffffffffffff, 0x7fffffffffffffff,
+ 0xffffffffffffffff };
+
+static int bitmap_set_fn(struct bitmap_level *bl, unsigned long offset,
+ unsigned int bit, void *__data)
+{
+ struct bitmap_set_data *data = __data;
+ unsigned long mask, overlap;
+ unsigned int nr_bits;
+
+ nr_bits = min(data->nr_bits, BLOCKS_PER_UNIT - bit);
+
+ mask = bit_masks[nr_bits] << bit;
+
+ /*
+ * Mask off any potential overlap, only sets contig regions
+ */
+ overlap = bl->map[offset] & mask;
+ if (overlap == mask) {
+ assert(data->fail_ok);
+ return 1;
+ }
+
+ while (overlap) {
+ unsigned long clear_mask = ~(1UL << ffz(~overlap));
+
+ mask &= clear_mask;
+ overlap &= clear_mask;
+ nr_bits--;
+ }
+
+ assert(mask);
+ assert(!(bl->map[offset] & mask));
+
+ bl->map[offset] |= mask;
+
+ if (!bl->level)
+ data->set_bits = nr_bits;
+
+ data->nr_bits = 1;
+ return bl->map[offset] != -1UL;
+}
+
+static void __bitmap_set(struct bitmap *bitmap, uint64_t bit_nr,
+ struct bitmap_set_data *data)
+{
+ unsigned int set_bits, nr_bits = data->nr_bits;
+
+ if (bitmap->first_free >= bit_nr &&
+ bitmap->first_free < bit_nr + data->nr_bits)
+ bitmap->first_free = -1ULL;
+
+ set_bits = 0;
+ while (nr_bits) {
+ bitmap_handler(bitmap, bit_nr, bitmap_set_fn, data);
+ set_bits += data->set_bits;
+
+ if (data->set_bits != (BLOCKS_PER_UNIT - nr_bits))
+ break;
+
+ nr_bits -= data->set_bits;
+ bit_nr += data->set_bits;
+
+ data->nr_bits = nr_bits;
+ data->fail_ok = 1;
+ }
+
+ data->set_bits = set_bits;
+}
+
+void bitmap_set(struct bitmap *bitmap, uint64_t bit_nr)
+{
+ struct bitmap_set_data data = { .nr_bits = 1, };
+
+ __bitmap_set(bitmap, bit_nr, &data);
+}
+
+unsigned int bitmap_set_nr(struct bitmap *bitmap, uint64_t bit_nr, unsigned int nr_bits)
+{
+ struct bitmap_set_data data = { .nr_bits = nr_bits, };
+
+ __bitmap_set(bitmap, bit_nr, &data);
+ return data.set_bits;
+}
+
+static int bitmap_isset_fn(struct bitmap_level *bl, unsigned long offset,
+ unsigned int bit, void *unused)
+{
+ return (bl->map[offset] & (1UL << bit)) != 0;
+}
+
+int bitmap_isset(struct bitmap *bitmap, uint64_t bit_nr)
+{
+ return bitmap_handler_topdown(bitmap, bit_nr, bitmap_isset_fn, NULL);
+}
+
+static uint64_t bitmap_find_first_free(struct bitmap *bitmap, unsigned int level,
+ uint64_t index)
+{
+ unsigned long j;
+ int i;
+
+ /*
+ * Start at the bottom, then converge towards first free bit at the top
+ */
+ for (i = level; i >= 0; i--) {
+ struct bitmap_level *bl = &bitmap->levels[i];
+
+ if (index >= bl->map_size) {
+ index = -1ULL;
+ break;
+ }
+
+ for (j = index; j < bl->map_size; j++) {
+ if (bl->map[j] == -1UL)
+ continue;
+
+ /*
+ * First free bit here is our index into the first
+ * free bit at the next higher level
+ */
+ index = (j << UNIT_SHIFT) + ffz(bl->map[j]);
+ break;
+ }
+ }
+
+ return index;
+}
+
+uint64_t bitmap_first_free(struct bitmap *bitmap)
+{
+ if (firstfree_valid(bitmap))
+ return bitmap->first_free;
+
+ bitmap->first_free = bitmap_find_first_free(bitmap, bitmap->nr_levels - 1, 0);
+ return bitmap->first_free;
+}
+
+struct bitmap_next_free_data {
+ unsigned int level;
+ unsigned long offset;
+ uint64_t bit;
+};
+
+static int bitmap_next_free_fn(struct bitmap_level *bl, unsigned long offset,
+ unsigned int bit, void *__data)
+{
+ struct bitmap_next_free_data *data = __data;
+ uint64_t mask = ~((1UL << ((data->bit & BLOCKS_PER_UNIT_MASK) + 1)) - 1);
+
+ if (!(mask & bl->map[offset]))
+ return 0;
+
+ if (bl->map[offset] != -1UL) {
+ data->level = bl->level;
+ data->offset = offset;
+ return 1;
+ }
+
+ data->bit = (data->bit + BLOCKS_PER_UNIT - 1) / BLOCKS_PER_UNIT;
+ return 0;
+}
+
+/*
+ * 'bit_nr' is already set. Find the next free bit after this one.
+ */
+uint64_t bitmap_next_free(struct bitmap *bitmap, uint64_t bit_nr)
+{
+ struct bitmap_next_free_data data = { .level = -1U, .bit = bit_nr, };
+
+ if (firstfree_valid(bitmap) && bit_nr < bitmap->first_free)
+ return bitmap->first_free;
+
+ if (!bitmap_handler(bitmap, bit_nr, bitmap_next_free_fn, &data))
+ return bitmap_first_free(bitmap);
+
+ assert(data.level != -1U);
+
+ return bitmap_find_first_free(bitmap, data.level, data.offset);
+}
diff --git a/lib/bitmap.h b/lib/bitmap.h
new file mode 100644
index 00000000..41c0fd8a
--- /dev/null
+++ b/lib/bitmap.h
@@ -0,0 +1,18 @@
+#ifndef FIO_BITMAP_H
+#define FIO_BITMAP_H
+
+#include <inttypes.h>
+
+struct bitmap;
+struct bitmap *bitmap_new(unsigned long nr_bits);
+void bitmap_free(struct bitmap *bm);
+
+void bitmap_clear(struct bitmap *bitmap, uint64_t bit_nr);
+void bitmap_set(struct bitmap *bitmap, uint64_t bit_nr);
+unsigned int bitmap_set_nr(struct bitmap *bitmap, uint64_t bit_nr, unsigned int nr_bits);
+int bitmap_isset(struct bitmap *bitmap, uint64_t bit_nr);
+uint64_t bitmap_first_free(struct bitmap *bitmap);
+uint64_t bitmap_next_free(struct bitmap *bitmap, uint64_t bit_nr);
+void bitmap_reset(struct bitmap *bitmap);
+
+#endif