bcache: A block layer cache

Does writethrough and writeback caching, handles unclean shutdown, and
has a bunch of other nifty features motivated by real world usage.

See the wiki at http://bcache.evilpiepirate.org for more.

Signed-off-by: Kent Overstreet <koverstreet@google.com>

1 files changed, 589 insertions, 0 deletions

diff --git a/drivers/md/bcache/util.h b/drivers/md/bcache/util.h
new file mode 100644
index 000000000000..56705fdcc149
--- /dev/null
+++ b/drivers/md/bcache/util.h
@@ -0,0 +1,589 @@
+
+#ifndef _BCACHE_UTIL_H
+#define _BCACHE_UTIL_H
+
+#include <linux/errno.h>
+#include <linux/kernel.h>
+#include <linux/llist.h>
+#include <linux/ratelimit.h>
+#include <linux/vmalloc.h>
+#include <linux/workqueue.h>
+
+#include "closure.h"
+
+#define PAGE_SECTORS            (PAGE_SIZE / 512)
+
+struct closure;
+
+#include <trace/events/bcache.h>
+
+#ifdef CONFIG_BCACHE_EDEBUG
+
+#define atomic_dec_bug(v)       BUG_ON(atomic_dec_return(v) < 0)
+#define atomic_inc_bug(v, i)    BUG_ON(atomic_inc_return(v) <= i)
+
+#else /* EDEBUG */
+
+#define atomic_dec_bug(v)       atomic_dec(v)
+#define atomic_inc_bug(v, i)    atomic_inc(v)
+
+#endif
+
+#define BITMASK(name, type, field, offset, size)                \
+static inline uint64_t name(const type *k)                      \
+{ return (k->field >> offset) & ~(((uint64_t) ~0) << size); }   \
+                                                                \
+static inline void SET_##name(type *k, uint64_t v)              \
+{                                                               \
+        k->field &= ~(~((uint64_t) ~0 << size) << offset);      \
+        k->field |= v << offset;                                \
+}
+
+#define DECLARE_HEAP(type, name)                                        \
+        struct {                                                        \
+                size_t size, used;                                      \
+                type *data;                                             \
+        } name
+
+#define init_heap(heap, _size, gfp)                                     \
+({                                                                      \
+        size_t _bytes;                                                  \
+        (heap)->used = 0;                                               \
+        (heap)->size = (_size);                                         \
+        _bytes = (heap)->size * sizeof(*(heap)->data);                  \
+        (heap)->data = NULL;                                            \
+        if (_bytes < KMALLOC_MAX_SIZE)                                  \
+                (heap)->data = kmalloc(_bytes, (gfp));                  \
+        if ((!(heap)->data) && ((gfp) & GFP_KERNEL))                    \
+                (heap)->data = vmalloc(_bytes);                         \
+        (heap)->data;                                                   \
+})
+
+#define free_heap(heap)                                                 \
+do {                                                                    \
+        if (is_vmalloc_addr((heap)->data))                              \
+                vfree((heap)->data);                                    \
+        else                                                            \
+                kfree((heap)->data);                                    \
+        (heap)->data = NULL;                                            \
+} while (0)
+
+#define heap_swap(h, i, j)      swap((h)->data[i], (h)->data[j])
+
+#define heap_sift(h, i, cmp)                                            \
+do {                                                                    \
+        size_t _r, _j = i;                                              \
+                                                                        \
+        for (; _j * 2 + 1 < (h)->used; _j = _r) {                       \
+                _r = _j * 2 + 1;                                        \
+                if (_r + 1 < (h)->used &&                               \
+                    cmp((h)->data[_r], (h)->data[_r + 1]))              \
+                        _r++;                                           \
+                                                                        \
+                if (cmp((h)->data[_r], (h)->data[_j]))                  \
+                        break;                                          \
+                heap_swap(h, _r, _j);                                   \
+        }                                                               \
+} while (0)
+
+#define heap_sift_down(h, i, cmp)                                       \
+do {                                                                    \
+        while (i) {                                                     \
+                size_t p = (i - 1) / 2;                                 \
+                if (cmp((h)->data[i], (h)->data[p]))                    \
+                        break;                                          \
+                heap_swap(h, i, p);                                     \
+                i = p;                                                  \
+        }                                                               \
+} while (0)
+
+#define heap_add(h, d, cmp)                                             \
+({                                                                      \
+        bool _r = !heap_full(h);                                        \
+        if (_r) {                                                       \
+                size_t _i = (h)->used++;                                \
+                (h)->data[_i] = d;                                      \
+                                                                        \
+                heap_sift_down(h, _i, cmp);                             \
+                heap_sift(h, _i, cmp);                                  \
+        }                                                               \
+        _r;                                                             \
+})
+
+#define heap_pop(h, d, cmp)                                             \
+({                                                                      \
+        bool _r = (h)->used;                                            \
+        if (_r) {                                                       \
+                (d) = (h)->data[0];                                     \
+                (h)->used--;                                            \
+                heap_swap(h, 0, (h)->used);                             \
+                heap_sift(h, 0, cmp);                                   \
+        }                                                               \
+        _r;                                                             \
+})
+
+#define heap_peek(h)    ((h)->size ? (h)->data[0] : NULL)
+
+#define heap_full(h)    ((h)->used == (h)->size)
+
+#define DECLARE_FIFO(type, name)                                        \
+        struct {                                                        \
+                size_t front, back, size, mask;                         \
+                type *data;                                             \
+        } name
+
+#define fifo_for_each(c, fifo, iter)                                    \
+        for (iter = (fifo)->front;                                      \
+             c = (fifo)->data[iter], iter != (fifo)->back;              \
+             iter = (iter + 1) & (fifo)->mask)
+
+#define __init_fifo(fifo, gfp)                                          \
+({                                                                      \
+        size_t _allocated_size, _bytes;                                 \
+        BUG_ON(!(fifo)->size);                                          \
+                                                                        \
+        _allocated_size = roundup_pow_of_two((fifo)->size + 1);         \
+        _bytes = _allocated_size * sizeof(*(fifo)->data);               \
+                                                                        \
+        (fifo)->mask = _allocated_size - 1;                             \
+        (fifo)->front = (fifo)->back = 0;                               \
+        (fifo)->data = NULL;                                            \
+                                                                        \
+        if (_bytes < KMALLOC_MAX_SIZE)                                  \
+                (fifo)->data = kmalloc(_bytes, (gfp));                  \
+        if ((!(fifo)->data) && ((gfp) & GFP_KERNEL))                    \
+                (fifo)->data = vmalloc(_bytes);                         \
+        (fifo)->data;                                                   \
+})
+
+#define init_fifo_exact(fifo, _size, gfp)                               \
+({                                                                      \
+        (fifo)->size = (_size);                                         \
+        __init_fifo(fifo, gfp);                                         \
+})
+
+#define init_fifo(fifo, _size, gfp)                                     \
+({                                                                      \
+        (fifo)->size = (_size);                                         \
+        if ((fifo)->size > 4)                                           \
+                (fifo)->size = roundup_pow_of_two((fifo)->size) - 1;    \
+        __init_fifo(fifo, gfp);                                         \
+})
+
+#define free_fifo(fifo)                                                 \
+do {                                                                    \
+        if (is_vmalloc_addr((fifo)->data))                              \
+                vfree((fifo)->data);                                    \
+        else                                                            \
+                kfree((fifo)->data);                                    \
+        (fifo)->data = NULL;                                            \
+} while (0)
+
+#define fifo_used(fifo)         (((fifo)->back - (fifo)->front) & (fifo)->mask)
+#define fifo_free(fifo)         ((fifo)->size - fifo_used(fifo))
+
+#define fifo_empty(fifo)        (!fifo_used(fifo))
+#define fifo_full(fifo)         (!fifo_free(fifo))
+
+#define fifo_front(fifo)        ((fifo)->data[(fifo)->front])
+#define fifo_back(fifo)                                                 \
+        ((fifo)->data[((fifo)->back - 1) & (fifo)->mask])
+
+#define fifo_idx(fifo, p)       (((p) - &fifo_front(fifo)) & (fifo)->mask)
+
+#define fifo_push_back(fifo, i)                                         \
+({                                                                      \
+        bool _r = !fifo_full((fifo));                                   \
+        if (_r) {                                                       \
+                (fifo)->data[(fifo)->back++] = (i);                     \
+                (fifo)->back &= (fifo)->mask;                           \
+        }                                                               \
+        _r;                                                             \
+})
+
+#define fifo_pop_front(fifo, i)                                         \
+({                                                                      \
+        bool _r = !fifo_empty((fifo));                                  \
+        if (_r) {                                                       \
+                (i) = (fifo)->data[(fifo)->front++];                    \
+                (fifo)->front &= (fifo)->mask;                          \
+        }                                                               \
+        _r;                                                             \
+})
+
+#define fifo_push_front(fifo, i)                                        \
+({                                                                      \
+        bool _r = !fifo_full((fifo));                                   \
+        if (_r) {                                                       \
+                --(fifo)->front;                                        \
+                (fifo)->front &= (fifo)->mask;                          \
+                (fifo)->data[(fifo)->front] = (i);                      \
+        }                                                               \
+        _r;                                                             \
+})
+
+#define fifo_pop_back(fifo, i)                                          \
+({                                                                      \
+        bool _r = !fifo_empty((fifo));                                  \
+        if (_r) {                                                       \
+                --(fifo)->back;                                         \
+                (fifo)->back &= (fifo)->mask;                           \
+                (i) = (fifo)->data[(fifo)->back]                        \
+        }                                                               \
+        _r;                                                             \
+})
+
+#define fifo_push(fifo, i)      fifo_push_back(fifo, (i))
+#define fifo_pop(fifo, i)       fifo_pop_front(fifo, (i))
+
+#define fifo_swap(l, r)                                                 \
+do {                                                                    \
+        swap((l)->front, (r)->front);                                   \
+        swap((l)->back, (r)->back);                                     \
+        swap((l)->size, (r)->size);                                     \
+        swap((l)->mask, (r)->mask);                                     \
+        swap((l)->data, (r)->data);                                     \
+} while (0)
+
+#define fifo_move(dest, src)                                            \
+do {                                                                    \
+        typeof(*((dest)->data)) _t;                                     \
+        while (!fifo_full(dest) &&                                      \
+               fifo_pop(src, _t))                                       \
+                fifo_push(dest, _t);                                    \
+} while (0)
+
+/*
+ * Simple array based allocator - preallocates a number of elements and you can
+ * never allocate more than that, also has no locking.
+ *
+ * Handy because if you know you only need a fixed number of elements you don't
+ * have to worry about memory allocation failure, and sometimes a mempool isn't
+ * what you want.
+ *
+ * We treat the free elements as entries in a singly linked list, and the
+ * freelist as a stack - allocating and freeing push and pop off the freelist.
+ */
+
+#define DECLARE_ARRAY_ALLOCATOR(type, name, size)                       \
+        struct {                                                        \
+                type    *freelist;                                      \
+                type    data[size];                                     \
+        } name
+
+#define array_alloc(array)                                              \
+({                                                                      \
+        typeof((array)->freelist) _ret = (array)->freelist;             \
+                                                                        \
+        if (_ret)                                                       \
+                (array)->freelist = *((typeof((array)->freelist) *) _ret);\
+                                                                        \
+        _ret;                                                           \
+})
+
+#define array_free(array, ptr)                                          \
+do {                                                                    \
+        typeof((array)->freelist) _ptr = ptr;                           \
+                                                                        \
+        *((typeof((array)->freelist) *) _ptr) = (array)->freelist;      \
+        (array)->freelist = _ptr;                                       \
+} while (0)
+
+#define array_allocator_init(array)                                     \
+do {                                                                    \
+        typeof((array)->freelist) _i;                                   \
+                                                                        \
+        BUILD_BUG_ON(sizeof((array)->data[0]) < sizeof(void *));        \
+        (array)->freelist = NULL;                                       \
+                                                                        \
+        for (_i = (array)->data;                                        \
+             _i < (array)->data + ARRAY_SIZE((array)->data);            \
+             _i++)                                                      \
+                array_free(array, _i);                                  \
+} while (0)
+
+#define array_freelist_empty(array)     ((array)->freelist == NULL)
+
+#define ANYSINT_MAX(t)                                                  \
+        ((((t) 1 << (sizeof(t) * 8 - 2)) - (t) 1) * (t) 2 + (t) 1)
+
+int strtoint_h(const char *, int *);
+int strtouint_h(const char *, unsigned int *);
+int strtoll_h(const char *, long long *);
+int strtoull_h(const char *, unsigned long long *);
+
+static inline int strtol_h(const char *cp, long *res)
+{
+#if BITS_PER_LONG == 32
+        return strtoint_h(cp, (int *) res);
+#else
+        return strtoll_h(cp, (long long *) res);
+#endif
+}
+
+static inline int strtoul_h(const char *cp, long *res)
+{
+#if BITS_PER_LONG == 32
+        return strtouint_h(cp, (unsigned int *) res);
+#else
+        return strtoull_h(cp, (unsigned long long *) res);
+#endif
+}
+
+#define strtoi_h(cp, res)                                               \
+        (__builtin_types_compatible_p(typeof(*res), int)                \
+        ? strtoint_h(cp, (void *) res)                                  \
+        : __builtin_types_compatible_p(typeof(*res), long)              \
+        ? strtol_h(cp, (void *) res)                                    \
+        : __builtin_types_compatible_p(typeof(*res), long long)         \
+        ? strtoll_h(cp, (void *) res)                                   \
+        : __builtin_types_compatible_p(typeof(*res), unsigned int)      \
+        ? strtouint_h(cp, (void *) res)                                 \
+        : __builtin_types_compatible_p(typeof(*res), unsigned long)     \
+        ? strtoul_h(cp, (void *) res)                                   \
+        : __builtin_types_compatible_p(typeof(*res), unsigned long long)\
+        ? strtoull_h(cp, (void *) res) : -EINVAL)
+
+#define strtoul_safe(cp, var)                                           \
+({                                                                      \
+        unsigned long _v;                                               \
+        int _r = kstrtoul(cp, 10, &_v);                                 \
+        if (!_r)                                                        \
+                var = _v;                                               \
+        _r;                                                             \
+})
+
+#define strtoul_safe_clamp(cp, var, min, max)                           \
+({                                                                      \
+        unsigned long _v;                                               \
+        int _r = kstrtoul(cp, 10, &_v);                                 \
+        if (!_r)                                                        \
+                var = clamp_t(typeof(var), _v, min, max);               \
+        _r;                                                             \
+})
+
+#define snprint(buf, size, var)                                         \
+        snprintf(buf, size,                                             \
+                __builtin_types_compatible_p(typeof(var), int)          \
+                     ? "%i\n" :                                         \
+                __builtin_types_compatible_p(typeof(var), unsigned)     \
+                     ? "%u\n" :                                         \
+                __builtin_types_compatible_p(typeof(var), long)         \
+                     ? "%li\n" :                                        \
+                __builtin_types_compatible_p(typeof(var), unsigned long)\
+                     ? "%lu\n" :                                        \
+                __builtin_types_compatible_p(typeof(var), int64_t)      \
+                     ? "%lli\n" :                                       \
+                __builtin_types_compatible_p(typeof(var), uint64_t)     \
+                     ? "%llu\n" :                                       \
+                __builtin_types_compatible_p(typeof(var), const char *) \
+                     ? "%s\n" : "%i\n", var)
+
+ssize_t hprint(char *buf, int64_t v);
+
+bool is_zero(const char *p, size_t n);
+int parse_uuid(const char *s, char *uuid);
+
+ssize_t snprint_string_list(char *buf, size_t size, const char * const list[],
+                            size_t selected);
+
+ssize_t read_string_list(const char *buf, const char * const list[]);
+
+struct time_stats {
+        /*
+         * all fields are in nanoseconds, averages are ewmas stored left shifted
+         * by 8
+         */
+        uint64_t        max_duration;
+        uint64_t        average_duration;
+        uint64_t        average_frequency;
+        uint64_t        last;
+};
+
+void time_stats_update(struct time_stats *stats, uint64_t time);
+
+#define NSEC_PER_ns                     1L
+#define NSEC_PER_us                     NSEC_PER_USEC
+#define NSEC_PER_ms                     NSEC_PER_MSEC
+#define NSEC_PER_sec                    NSEC_PER_SEC
+
+#define __print_time_stat(stats, name, stat, units)                     \
+        sysfs_print(name ## _ ## stat ## _ ## units,                    \
+                    div_u64((stats)->stat >> 8, NSEC_PER_ ## units))
+
+#define sysfs_print_time_stats(stats, name,                             \
+                               frequency_units,                         \
+                               duration_units)                          \
+do {                                                                    \
+        __print_time_stat(stats, name,                                  \
+                          average_frequency,    frequency_units);       \
+        __print_time_stat(stats, name,                                  \
+                          average_duration,     duration_units);        \
+        __print_time_stat(stats, name,                                  \
+                          max_duration,         duration_units);        \
+                                                                        \
+        sysfs_print(name ## _last_ ## frequency_units, (stats)->last    \
+                    ? div_s64(local_clock() - (stats)->last,            \
+                              NSEC_PER_ ## frequency_units)             \
+                    : -1LL);                                            \
+} while (0)
+
+#define sysfs_time_stats_attribute(name,                                \
+                                   frequency_units,                     \
+                                   duration_units)                      \
+read_attribute(name ## _average_frequency_ ## frequency_units);         \
+read_attribute(name ## _average_duration_ ## duration_units);           \
+read_attribute(name ## _max_duration_ ## duration_units);               \
+read_attribute(name ## _last_ ## frequency_units)
+
+#define sysfs_time_stats_attribute_list(name,                           \
+                                        frequency_units,                \
+                                        duration_units)                 \
+&sysfs_ ## name ## _average_frequency_ ## frequency_units,              \
+&sysfs_ ## name ## _average_duration_ ## duration_units,                \
+&sysfs_ ## name ## _max_duration_ ## duration_units,                    \
+&sysfs_ ## name ## _last_ ## frequency_units,
+
+#define ewma_add(ewma, val, weight, factor)                             \
+({                                                                      \
+        (ewma) *= (weight) - 1;                                         \
+        (ewma) += (val) << factor;                                      \
+        (ewma) /= (weight);                                             \
+        (ewma) >> factor;                                               \
+})
+
+struct ratelimit {
+        uint64_t                next;
+        unsigned                rate;
+};
+
+static inline void ratelimit_reset(struct ratelimit *d)
+{
+        d->next = local_clock();
+}
+
+unsigned next_delay(struct ratelimit *d, uint64_t done);
+
+#define __DIV_SAFE(n, d, zero)                                          \
+({                                                                      \
+        typeof(n) _n = (n);                                             \
+        typeof(d) _d = (d);                                             \
+        _d ? _n / _d : zero;                                            \
+})
+
+#define DIV_SAFE(n, d)  __DIV_SAFE(n, d, 0)
+
+#define container_of_or_null(ptr, type, member)                         \
+({                                                                      \
+        typeof(ptr) _ptr = ptr;                                         \
+        _ptr ? container_of(_ptr, type, member) : NULL;                 \
+})
+
+#define RB_INSERT(root, new, member, cmp)                               \
+({                                                                      \
+        __label__ dup;                                                  \
+        struct rb_node **n = &(root)->rb_node, *parent = NULL;          \
+        typeof(new) this;                                               \
+        int res, ret = -1;                                              \
+                                                                        \
+        while (*n) {                                                    \
+                parent = *n;                                            \
+                this = container_of(*n, typeof(*(new)), member);        \
+                res = cmp(new, this);                                   \
+                if (!res)                                               \
+                        goto dup;                                       \
+                n = res < 0                                             \
+                        ? &(*n)->rb_left                                \
+                        : &(*n)->rb_right;                              \
+        }                                                               \
+                                                                        \
+        rb_link_node(&(new)->member, parent, n);                        \
+        rb_insert_color(&(new)->member, root);                          \
+        ret = 0;                                                        \
+dup:                                                                    \
+        ret;                                                            \
+})
+
+#define RB_SEARCH(root, search, member, cmp)                            \
+({                                                                      \
+        struct rb_node *n = (root)->rb_node;                            \
+        typeof(&(search)) this, ret = NULL;                             \
+        int res;                                                        \
+                                                                        \
+        while (n) {                                                     \
+                this = container_of(n, typeof(search), member);         \
+                res = cmp(&(search), this);                             \
+                if (!res) {                                             \
+                        ret = this;                                     \
+                        break;                                          \
+                }                                                       \
+                n = res < 0                                             \
+                        ? n->rb_left                                    \
+                        : n->rb_right;                                  \
+        }                                                               \
+        ret;                                                            \
+})
+
+#define RB_GREATER(root, search, member, cmp)                           \
+({                                                                      \
+        struct rb_node *n = (root)->rb_node;                            \
+        typeof(&(search)) this, ret = NULL;                             \
+        int res;                                                        \
+                                                                        \
+        while (n) {                                                     \
+                this = container_of(n, typeof(search), member);         \
+                res = cmp(&(search), this);                             \
+                if (res < 0) {                                          \
+                        ret = this;                                     \
+                        n = n->rb_left;                                 \
+                } else                                                  \
+                        n = n->rb_right;                                \
+        }                                                               \
+        ret;                                                            \
+})
+
+#define RB_FIRST(root, type, member)                                    \
+        container_of_or_null(rb_first(root), type, member)
+
+#define RB_LAST(root, type, member)                                     \
+        container_of_or_null(rb_last(root), type, member)
+
+#define RB_NEXT(ptr, member)                                            \
+        container_of_or_null(rb_next(&(ptr)->member), typeof(*ptr), member)
+
+#define RB_PREV(ptr, member)                                            \
+        container_of_or_null(rb_prev(&(ptr)->member), typeof(*ptr), member)
+
+/* Does linear interpolation between powers of two */
+static inline unsigned fract_exp_two(unsigned x, unsigned fract_bits)
+{
+        unsigned fract = x & ~(~0 << fract_bits);
+
+        x >>= fract_bits;
+        x   = 1 << x;
+        x  += (x * fract) >> fract_bits;
+
+        return x;
+}
+
+#define bio_end(bio)    ((bio)->bi_sector + bio_sectors(bio))
+
+void bio_map(struct bio *bio, void *base);
+
+int bio_alloc_pages(struct bio *bio, gfp_t gfp);
+
+static inline sector_t bdev_sectors(struct block_device *bdev)
+{
+        return bdev->bd_inode->i_size >> 9;
+}
+
+#define closure_bio_submit(bio, cl, dev)                                \
+do {                                                                    \
+        closure_get(cl);                                                \
+        bch_generic_make_request(bio, &(dev)->bio_split_hook);          \
+} while (0)
+
+uint64_t crc64_update(uint64_t, const void *, size_t);
+uint64_t crc64(const void *, size_t);
+
+#endif /* _BCACHE_UTIL_H */