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Date: Mon, 14 Jun 2010 09:16:59 -0700
From: Kent Overstreet <kent.overstreet@...il.com>
To: linux-kernel@...r.kernel.org
Subject: [RFC][PATCH 3/3] Bcache: Version 5 - The code
block/Makefile | 2 +
block/bcache.c | 3485 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 3487 insertions(+), 0 deletions(-)
diff --git a/block/Makefile b/block/Makefile
index 0bb499a..617845c 100644
--- a/block/Makefile
+++ b/block/Makefile
@@ -15,3 +15,5 @@ obj-$(CONFIG_IOSCHED_CFQ) += cfq-iosched.o
obj-$(CONFIG_BLOCK_COMPAT) += compat_ioctl.o
obj-$(CONFIG_BLK_DEV_INTEGRITY) += blk-integrity.o
+
+obj-$(CONFIG_BLK_CACHE) += bcache.o
diff --git a/block/bcache.c b/block/bcache.c
new file mode 100644
index 0000000..b41f64a
--- /dev/null
+++ b/block/bcache.c
@@ -0,0 +1,3485 @@
+/*
+ * Copyright (C) 2010 Kent Overstreet <kent.overstreet@...il.com>
+ *
+ * Uses a block device as cache for other block devices; optimized for SSDs.
+ * All allocation is done in buckets, which should match the erase block size
+ * of the device.
+ *
+ * Buckets containing cached data are kept on a heap sorted by priority;
+ * bucket priority is increased on cache hit, and periodically all the buckets
+ * on the heap have their priority scaled down. This currently is just used as
+ * an LRU but in the future should allow for more intelligent heuristics.
+ *
+ * Buckets have an 8 bit counter; freeing is accomplished by incrementing the
+ * counter. Garbage collection is used to remove stale pointers.
+ *
+ * Indexing is done via a btree; nodes are not necessarily fully sorted, rather
+ * as keys are inserted we only sort the pages that have not yet been written.
+ * When garbage collection is run, we resort the entire node.
+ *
+ * All configuration is done via sysfs; see Documentation/bcache.txt.
+ */
+
+#define pr_fmt(fmt) "bcache: %s() " fmt "\n", __func__
+
+#include <linux/blkdev.h>
+#include <linux/buffer_head.h>
+#include <linux/debugfs.h>
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/init.h>
+#include <linux/kobject.h>
+#include <linux/list.h>
+#include <linux/module.h>
+#include <linux/page-flags.h>
+#include <linux/random.h>
+#include <linux/sched.h>
+#include <linux/seq_file.h>
+#include <linux/slab.h>
+#include <linux/sort.h>
+#include <linux/string.h>
+#include <linux/sysfs.h>
+#include <linux/types.h>
+#include <linux/workqueue.h>
+
+/*
+ * Todo:
+ * garbage collection: in non root nodes pointers are invalidated if previous
+ * bucket overwrites, need to remove them.
+ *
+ * echo "`blkid /dev/loop0 -s UUID -o value` /dev/loop0"
+ *
+ * Error handling in fill_bucket
+ *
+ * If btree_insert_recurse can't recurse, it's critical that it tries harder
+ * and/or returns the error all the way up if it came from a write - verify
+ *
+ * Fix cache hit counting, split cache hits shouldn't count for each split
+ *
+ * Need to insert null keys on write if there's multiple cache devices, and on
+ * error
+ *
+ * bio_split_front: can't modify io_vec if original bio was cloned
+ * no, it's more complicated than that
+ *
+ * Fix mark and sweep garbage collection, check key merging in insert_one_key
+ *
+ * get_bucket should be checking the gen, not priority
+ *
+ * Make registering partitions to cache work
+ *
+ * Test module load/unload
+ *
+ * bio_insert: don't insert keys until write completes successfully
+ *
+ * Check if a device is opened read/write when caching is turned on or off for
+ * it, and invalidate cached data (Idea: pin the first 4k? 8k? in the cache,
+ * verify it against the cached copy when caching's turned on)
+ *
+ * Need to make sure the page cache writes out our dirty pages either not at
+ * all, or preferably correctly; if the latter get_bucket won't need to write
+ * anymore.
+ *
+ * IO error handling
+ *
+ * Future:
+ * Journaling
+ * Write behind
+ * Checksumming
+ * SSDs that don't support trim would probably benefit from batching up writes
+ * to a full erase block.
+ *
+ * Stuff that should be made generic and taken out:
+ * fifos
+ * heap code
+ * bio_split_front()
+ * maybe eventually the search context stuff
+ */
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Kent Overstreet <kent.overstreet@...il.com>");
+
+#define UUIDS_PER_SB 256
+#define SB_SECTOR 8
+#define UUID_SECTOR 16
+#define PRIO_SECTOR 24
+
+/*
+ * Page 0: unused
+ * Page 1: superblock
+ * Page 2: device UUIDs
+ * Page 3+: bucket priorities
+ */
+
+#define DECLARE_FIFO(type, name) \
+ struct { \
+ size_t front, back, size; \
+ type *data; \
+ } name;
+
+#define init_fifo(f, s, gfp) ({ \
+ (f)->data = NULL; \
+ (f)->front = (f)->back = 0; \
+ (f)->size = roundup_pow_of_two(s) - 1; \
+ if ((f)->size * sizeof(*(f)->data) >= KMALLOC_MAX_SIZE) \
+ (f)->data = vmalloc((f)->size * sizeof(*(f)->data));\
+ else if ((f)->size > 0) \
+ (f)->data = kmalloc((f)->size * sizeof(*(f)->data), gfp);\
+ (f)->data; })
+
+#define free_fifo(f) do { \
+ if ((f)->size * sizeof(*(f)->data) >= KMALLOC_MAX_SIZE) \
+ vfree((f)->data); \
+ else \
+ kfree((f)->data); \
+ (f)->data = NULL; \
+} while (0)
+
+#define fifo_push(f, i) ({ \
+ bool _r = false; \
+ if ((((f)->front + 1) & (f)->size) != (f)->back) { \
+ _r = true; \
+ (f)->data[(f)->front++] = i; \
+ (f)->front &= (f)->size; \
+ } _r; })
+
+#define fifo_pop(f, i) ({ \
+ bool _r = false; \
+ if ((f)->front != (f)->back) { \
+ _r = true; \
+ i = (f)->data[(f)->back++]; \
+ (f)->back &= (f)->size; \
+ } _r; })
+
+#define fifo_full(f) ((((f)->front + 1) & (f)->size) == (f)->back)
+
+/*
+ * These are subject to the infamous aba problem...
+ */
+
+#define lockless_list_push(new, list, member) \
+ do { \
+ (new)->member = list; \
+ } while (cmpxchg(&(list), (new)->member, new) != (new)->member) \
+
+#define lockless_list_pop(list, member) ({ \
+ typeof(list) _r; \
+ do { \
+ _r = list; \
+ } while (_r && cmpxchg(&(list), _r, _r->member) != _r); \
+ _r; })
+
+#define DECLARE_HEAP(type, name) \
+ struct { \
+ size_t size; \
+ type *data; \
+ } name;
+
+#define init_heap(h, s, gfp) ({ \
+ (h)->data = NULL; \
+ (h)->size = 0; \
+ if (s * sizeof(*(h)->data) >= KMALLOC_MAX_SIZE) \
+ (h)->data = vmalloc(s * sizeof(*(h)->data)); \
+ else if (s > 0) \
+ (h)->data = kmalloc(s * sizeof(*(h)->data), gfp);\
+ (h)->data; })
+
+struct search_context;
+struct cached_bucket;
+
+typedef void (search_fn) (struct search_context *);
+
+struct cache_sb {
+ uint8_t magic[16];
+#define CACHE_CLEAN 1
+ uint32_t version;
+ uint16_t block_size; /* sectors */
+ uint16_t bucket_size; /* sectors */
+ uint32_t journal_start; /* buckets */
+ uint32_t first_bucket; /* start of data */
+ uint64_t nbuckets; /* device size */
+ uint64_t btree_root;
+ uint16_t btree_level;
+};
+
+struct bucket {
+ size_t heap;
+ atomic_t pin;
+ uint16_t priority;
+ uint8_t gen;
+ uint8_t last_gc;
+};
+
+struct bucket_gc {
+ uint8_t gen;
+ uint8_t mark;
+};
+
+struct bucket_disk {
+ uint16_t priority;
+ uint8_t gen;
+} __attribute((packed));
+
+struct btree_node_header {
+ uint32_t csum;
+ uint32_t nkeys;
+ uint64_t random;
+};
+
+struct btree_key {
+ uint64_t key;
+ uint64_t ptr;
+};
+
+struct cache_device {
+ struct list_head list;
+ struct cache_sb sb;
+ struct page *sb_page;
+ struct bio *sb_bio;
+ spinlock_t sb_lock;
+
+ struct kobject kobj;
+ struct block_device *bdev;
+ struct module *owner;
+ struct dentry *debug;
+ struct work_struct work;
+
+ /*
+ * Buckets used for cached data go on the heap. The heap is ordered by
+ * bucket->priority; a priority of ~0 indicates a btree bucket. Priority
+ * is increased on cache hit, and periodically all the buckets on the
+ * heap have their priority scaled down by a linear function.
+ */
+ spinlock_t bucket_lock;
+ struct bucket **heap;
+ struct bucket *buckets;
+ struct bucket_disk *disk_buckets;
+ size_t heap_size;
+ long rescale;
+ uint8_t need_gc;
+
+ struct bio *priority_bio;
+
+ struct semaphore gc_lock;
+ struct bucket_gc *garbage;
+
+ int btree_buckets_cached;
+ struct list_head lru;
+
+ DECLARE_FIFO(long, free);
+
+ /*struct gendisk *devices[UUIDS_PER_SB];*/
+ short devices[UUIDS_PER_SB];
+ struct buffer_head *uuids;
+
+ unsigned long cache_hits;
+ unsigned long sectors_written;
+
+ struct cached_bucket *root;
+};
+
+struct open_bucket {
+ struct list_head list;
+ struct cache_device *cache;
+ struct task_struct *last;
+
+ struct btree_key key;
+ sector_t offset;
+ unsigned sectors_free;
+ uint8_t gen;
+};
+
+struct cached_dev {
+ struct kobject kobj;
+ struct block_device *bdev;
+ struct module *owner;
+ struct work_struct work;
+};
+
+struct journal_header {
+ uint32_t csum;
+ uint32_t seq;
+ uint32_t last_open_entry;
+ uint32_t nr_entries;
+};
+
+struct cached_bucket {
+ struct rw_semaphore lock;
+ struct list_head lru;
+ struct search_context *wait;
+ struct cache_device *c; /* for bio_add_work_unlock */
+
+ atomic_t nread;
+ sector_t offset;
+ int level;
+
+ struct page *pages[];
+};
+
+struct search_context {
+ struct work_struct w;
+ struct search_context *next;
+ search_fn *end_fn;
+ search_fn *parent;
+ atomic_t remaining;
+#define SEARCH_BLOCK 1
+#define SEARCH_WAITING 2
+ int flags;
+
+ struct btree_key new_keys[2];
+ int nkeys;
+ int level;
+ struct btree_key *keylist;
+ int nkeylist;
+
+ int error;
+ void *q;
+ struct bio *bio;
+
+ struct bio *cache_bio;
+ bio_end_io_t *bi_end_io;
+ void *bi_private;
+};
+
+static const char bcache_magic[] = {
+ 0xc6, 0x85, 0x73, 0xf6, 0x4e, 0x1a, 0x45, 0xca,
+ 0x82, 0x65, 0xf5, 0x7f, 0x48, 0xba, 0x6d, 0x81 };
+
+static struct kobject *bcache_kobj;
+/*
+ * We need a real search key
+ * static struct gendisk *devices[UUIDS_PER_SB];
+ */
+static char uuids[UUIDS_PER_SB*16];
+
+static LIST_HEAD(cache_devices);
+static LIST_HEAD(open_buckets);
+static DEFINE_SPINLOCK(open_bucket_lock);
+
+static DECLARE_WAIT_QUEUE_HEAD(pending);
+
+static struct workqueue_struct *delayed;
+
+/*
+ * Sysfs vars / tunables
+ */
+static unsigned long cache_hits, cache_misses, rescale = 204800; /* sectors */
+static uint16_t initial_priority = 32768;
+static uint16_t cache_hit_priority = 100, cache_hit_seek = 100;
+
+static struct bio *write_super(struct cache_device *);
+static struct bio *save_priorities(struct cache_device *);
+static void do_btree_gc(struct work_struct *);
+static void unregister_cache(struct kobject *);
+static void run_search(struct work_struct *);
+static void fill_bucket_endio(struct bio *bio, int error);
+static int request_hook_read(struct request_queue *q, struct bio *bio,
+ struct search_context *s);
+
+#define label(l, foo) if (0) { l: foo; }
+
+#define PAGE_SECTORS (PAGE_SIZE / 512)
+#define pages(c, s) (((sizeof(s) * c->sb.nbuckets) - 1) / PAGE_SIZE + 1)
+#define pages_per_bucket(b) (b->c->sb.bucket_size / PAGE_SECTORS)
+#define pages_per_btree (c->sb.bucket_size / PAGE_SECTORS)
+#define keys_per_page (PAGE_SIZE / sizeof(struct btree_key))
+
+#define bucket_to_sector(c, b) (((sector_t) (b) + c->sb.first_bucket) * c->sb.bucket_size)
+#define sector_to_struct(c, s) (c->buckets + sector_to_bucket(c, s))
+#define sector_to_gen(c, s) ({ smp_rmb(); sector_to_struct(c, s)->gen; })
+#define sector_to_priority(c, s) ({ smp_rmb(); sector_to_struct(c, s)->priority; })
+#define bucket_to_ptr(b) TREE_PTR(sector_to_gen(b->c, b->offset), 0, b->offset)
+
+#define sector_to_bucket(c, s) ({ \
+ uint64_t _s = (s); \
+ do_div(_s, c->sb.bucket_size); \
+ (long) _s - c->sb.first_bucket; })
+
+#define bucket_key(b) ((struct btree_key) { \
+ .key = node(data(b), header(b)->nkeys)->key,\
+ .ptr = bucket_to_ptr(b) })
+
+#define data(b) ((struct btree_key **) &(b)->pages[pages_per_bucket(b)])
+#define keys(i) (((struct btree_node_header *) *(i))->nkeys)
+#define rand(i) (((struct btree_node_header *) *(i))->random)
+#define header(b) ((struct btree_node_header *) data(b)[0])
+#define index(i, b) ((int) (i - data(b)))
+#define last_key(i) (node(i, keys(i))->key)
+
+/*
+ * key: 8 bit device, 56 bit offset
+ * value: 8 bit generation, 16 bit length, 40 bit offset
+ * All units are in sectors
+ */
+
+#define TREE_KEY(device, offset) (((uint64_t) device) << 56 | (offset))
+#define KEY_DEV(k) ((int) ((k)->key >> 56))
+#define KEY_OFFSET(k) ((k)->key & ~((int64_t) ~0 << 56))
+
+#define TREE_PTR(gen, length, offset) ((uint64_t) ((gen) | ((length) << 8) | ((uint64_t) (offset) << 24)))
+#define PTR_GEN(k) ((uint8_t) ((k)->ptr & ~(~0 << 8)))
+#define PTR_SIZE(k) ((int) ((k)->ptr >> 8) & ~(~0 << 16))
+#define PTR_OFFSET(k) ((int64_t) (((k)->ptr) >> 24))
+
+#define PTR_BUCKET(c, ptr) sector_to_struct(c, PTR_OFFSET(ptr))
+#define KEY_OVERLAP(i, j) ((int64_t) (i)->key - ((j)->key - PTR_SIZE(j)))
+
+static inline struct btree_key *node(struct btree_key *d[], int i)
+{
+ return d[i / keys_per_page] + (i % keys_per_page);
+}
+
+#define rw_lock(_w, _b) \
+ (_w ? down_write_nested(&(_b)->lock, (_b)->level + 1) \
+ : down_read_nested(&(_b)->lock, (_b)->level + 1))
+
+#define rw_unlock(_w, _b) \
+ (_w ? up_write(&(_b)->lock) : up_read(&(_b)->lock))
+
+static void check_bio(struct bio *bio)
+{
+ int i, size = 0;
+ struct bio_vec *bv;
+ BUG_ON(!bio->bi_vcnt);
+ BUG_ON(!bio->bi_size);
+
+ bio_for_each_segment(bv, bio, i)
+ size += bv->bv_len;
+
+ BUG_ON(size != bio->bi_size);
+ BUG_ON(size > queue_max_sectors(bdev_get_queue(bio->bi_bdev)) << 9);
+}
+
+static bool bio_reinit(struct bio *bio)
+{
+ if (atomic_cmpxchg(&bio->bi_remaining, 0, 1))
+ return false;
+
+ bio_get(bio);
+ bio->bi_next = NULL;
+ bio->bi_flags = 1 << BIO_UPTODATE;
+ bio->bi_rw = 0;
+ bio->bi_idx = 0;
+ bio->bi_phys_segments = 0;
+ bio->bi_size = 0;
+ bio->bi_seg_front_size = 0;
+ bio->bi_seg_back_size = 0;
+ bio->bi_comp_cpu = -1;
+ return true;
+}
+
+static struct bio *bio_split_front(struct bio *bio, int sectors,
+ struct bio *(alloc_fn)(int))
+{
+ int idx, vcnt = 0, nbytes = sectors << 9;
+ struct bio_vec *bv;
+ struct bio *ret = NULL;
+
+ struct bio *alloc(int n)
+ { return bio_kmalloc(GFP_NOIO, n); }
+
+ alloc_fn = alloc_fn ? : alloc;
+
+ BUG_ON(sectors <= 0);
+
+ if (nbytes >= bio->bi_size)
+ return bio;
+
+ bio_for_each_segment(bv, bio, idx) {
+ vcnt = idx - bio->bi_idx;
+
+ if (!nbytes &&
+ (ret = alloc_fn(0))) {
+ ret->bi_io_vec = bio->bi_io_vec + bio->bi_idx;
+ break;
+ } else if (nbytes && nbytes < bv->bv_len &&
+ (ret = alloc_fn(++vcnt))) {
+ memcpy(ret->bi_io_vec,
+ bio->bi_io_vec + bio->bi_idx,
+ sizeof(struct bio_vec) * vcnt);
+
+ ret->bi_io_vec[vcnt - 1].bv_len = nbytes;
+ bv->bv_offset += nbytes;
+ bv->bv_len -= nbytes;
+ break;
+ }
+
+ nbytes -= bv->bv_len;
+ }
+
+ if (ret) {
+ pr_debug("split %i sectors from %u %s, idx was %i now %i",
+ sectors, bio_sectors(bio),
+ nbytes ? "mid bio_vec" : "cleanly",
+ bio->bi_idx, idx);
+
+ ret->bi_bdev = bio->bi_bdev;
+ ret->bi_sector = bio->bi_sector;
+ ret->bi_size = sectors << 9;
+ ret->bi_rw = bio->bi_rw;
+ ret->bi_vcnt = vcnt;
+ ret->bi_max_vecs = vcnt;
+
+ bio->bi_sector += sectors;
+ bio->bi_size -= sectors << 9;
+ bio->bi_idx = idx;
+
+ ret->bi_private = bio;
+ ret->bi_end_io = bio_split_endio;
+ atomic_inc(&bio->bi_remaining);
+
+ check_bio(ret);
+ }
+
+ return ret;
+}
+
+static void submit_bio_list(int rw, struct bio *bio)
+{
+ while (bio) {
+ int max = queue_max_sectors(bdev_get_queue(bio->bi_bdev));
+ struct bio *split, *n = bio->bi_next;
+ bio->bi_next = NULL;
+ do {
+ if (!(split = bio_split_front(bio, max, NULL))) {
+ bio_endio(bio, -ENOMEM);
+ return;
+ }
+ submit_bio(rw, split);
+ } while (split != bio);
+
+ bio = n;
+ }
+}
+
+static int is_zero(void *p, size_t n)
+{
+ int i;
+ for (i = 0; i < n; i++)
+ if (((char *) p)[i])
+ return 0;
+ return 1;
+}
+
+static int parse_uuid(const char *s, char *uuid)
+{
+ int i, j, x;
+ memset(uuid, 0, 16);
+
+ for (i = 0, j = 0;
+ i < strspn(s, "-0123456789:ABCDEFabcdef") && j < 32;
+ i++) {
+ x = s[i] | 32;
+
+ switch (x) {
+ case '0'...'9':
+ x -= '0';
+ break;
+ case 'a'...'f':
+ x -= 'a' - 10;
+ break;
+ default:
+ continue;
+ }
+
+ x <<= ((j & 1) << 2);
+ uuid[j++ >> 1] |= x;
+ }
+ return i;
+}
+
+static int lookup_id(struct cache_device *c, int id)
+{
+ int dev;
+ for (dev = 0; dev < UUIDS_PER_SB; dev++)
+ if (c->devices[dev] == id)
+ break;
+
+ if (dev == UUIDS_PER_SB)
+ printk(KERN_DEBUG "bcache: unknown device %i", id);
+
+ return dev;
+}
+
+static int lookup_dev(struct cache_device *c, struct bio *bio)
+{ return lookup_id(c, bio->bi_bdev->bd_cache_identifier); }
+
+static void run_search(struct work_struct *w)
+{
+ struct search_context *s = container_of(w, struct search_context, w);
+ search_fn *f = NULL;
+ swap(f, s->end_fn);
+ atomic_set(&s->remaining, 1);
+ f(s);
+}
+
+static void put_search(struct search_context *s)
+{
+ BUG_ON(object_is_on_stack(s));
+ if (atomic_dec_and_test(&s->remaining)) {
+ BUG_ON(s->flags & SEARCH_WAITING);
+ smp_rmb();
+ if (!s->end_fn)
+ kfree(s);
+ else
+ BUG_ON(!queue_work(delayed, &s->w));
+ } else
+ BUG_ON(atomic_read(&s->remaining) < 0);
+}
+
+#define return_f(s, f, ...) \
+ do { \
+ if ((s) && !object_is_on_stack(s)) { \
+ (s)->end_fn = f; \
+ smp_wmb(); \
+ put_search(s); \
+ } \
+ return __VA_ARGS__; \
+ } while (0)
+
+#define run_wait_list(condition, list) ({ \
+ smp_mb(); \
+ if (condition) { \
+ struct search_context *_s, *_next; \
+ for (_s = xchg(&(list), NULL); _s; _s = _next) { \
+ _next = _s->next; \
+ _s->flags &= ~SEARCH_WAITING; \
+ if (_s->flags & SEARCH_BLOCK) \
+ wake_up(&pending); \
+ else \
+ put_search(_s); \
+ } \
+ } })
+
+#define wait_search(condition, list, s) ({ \
+ if (!(condition) && \
+ !IS_ERR(s = alloc_search(s)) && \
+ !((s)->flags & SEARCH_WAITING)) { \
+ (s)->flags |= SEARCH_WAITING; \
+ atomic_inc(&(s)->remaining); \
+ smp_mb__after_atomic_inc(); \
+ lockless_list_push(s, list, next); \
+ if ((s)->flags & SEARCH_BLOCK) \
+ wait_event(pending, condition); \
+ run_wait_list(condition, list); \
+ } \
+ s; })
+
+static struct search_context *alloc_search(struct search_context *s)
+{
+ struct search_context *r = s;
+ if (!s || (object_is_on_stack(s) &&
+ !(s->flags & SEARCH_BLOCK))) {
+ if (!(r = kzalloc(sizeof(*r), GFP_NOIO)))
+ return ERR_PTR(-ENOMEM);
+
+ if (s)
+ *r = *s;
+
+ atomic_set(&r->remaining, 1);
+ INIT_WORK(&r->w, run_search);
+ } else if (s && !(s->flags & SEARCH_BLOCK))
+ BUG_ON(!atomic_read(&(s)->remaining));
+ return r;
+}
+
+static uint8_t __inc_bucket_gen(struct cache_device *c, long b)
+{
+ uint8_t ret = ++c->buckets[b].gen;
+ pr_debug("bucket %li: %p %p %p", b,
+ __builtin_return_address(0),
+ __builtin_return_address(1),
+ __builtin_return_address(2));
+ c->need_gc = max_t(uint8_t, c->need_gc,
+ ret - c->buckets[b].last_gc);
+
+ if (c->need_gc > 64 && !down_trylock(&c->gc_lock)) {
+ long i;
+ memset(c->garbage, 0,
+ c->sb.nbuckets * sizeof(struct bucket_gc));
+
+ for (i = 0; i < c->sb.nbuckets; i++)
+ c->garbage[i].gen = c->buckets[i].gen;
+
+ pr_debug("starting gc");
+ INIT_WORK(&c->work, do_btree_gc);
+ queue_work(delayed, &c->work);
+ }
+ return ret;
+}
+
+static uint8_t inc_bucket_gen(struct cache_device *c, long b)
+{
+ uint8_t ret;
+ spin_lock(&c->bucket_lock);
+ ret = __inc_bucket_gen(c, b);
+ spin_unlock(&c->bucket_lock);
+ return ret;
+}
+
+#define inc_gen(c, o) inc_bucket_gen(c, sector_to_bucket(c, o))
+
+static struct bio *__rescale_heap(struct cache_device *c, int sectors)
+{
+ long i;
+ c->rescale -= sectors;
+ if (c->rescale <= 0) {
+ pr_debug("");
+ for (i = 0; i < c->heap_size; i++) {
+ uint16_t t = c->heap[i]->priority - 10;
+ BUG_ON(c->heap[i]->priority == (uint16_t) ~0);
+
+ c->heap[i]->priority =
+ t > c->heap[i]->priority ? 0 : t;
+ }
+ c->rescale += rescale;
+
+ return save_priorities(c);
+ }
+ return NULL;
+}
+
+static void rescale_heap(struct cache_device *c, int sectors)
+{
+ struct bio *bio;
+ spin_lock(&c->bucket_lock);
+ bio = __rescale_heap(c, sectors);
+ spin_unlock(&c->bucket_lock);
+ submit_bio_list(WRITE, bio);
+}
+
+#define heap_cmp(i, j) (c->heap[i]->priority >= c->heap[j]->priority)
+
+static void heap_swap(struct cache_device *c, long i, long j)
+{
+ swap(c->heap[i], c->heap[j]);
+ c->heap[i]->heap = i;
+ c->heap[j]->heap = j;
+}
+
+static int heap_cmp_swap(struct cache_device *c, long i, long j)
+{
+ if (heap_cmp(i, j))
+ return 1;
+ heap_swap(c, i, j);
+ return 0;
+}
+
+static void heap_sift(struct cache_device *c, long h)
+{
+ long r;
+
+ for (; h * 2 + 1 < c->heap_size; h = r) {
+ r = h * 2 + 1;
+ if (r + 1 < c->heap_size &&
+ heap_cmp(r, r + 1))
+ r++;
+
+ if (heap_cmp_swap(c, r, h))
+ break;
+ }
+}
+
+static void heap_insert(struct cache_device *c, long b)
+{
+ if (c->buckets[b].heap == -1) {
+ long p, h = c->heap_size++;
+
+ BUG_ON(c->buckets[b].priority == (uint16_t) ~0);
+ c->buckets[b].heap = h;
+ c->heap[h] = &c->buckets[b];
+
+ for (p = (h - 1) / 2; p; h = p, p = (h - 1) / 2)
+ if (heap_cmp_swap(c, h, p))
+ break;
+
+ heap_sift(c, h);
+
+ pr_debug("inserted bucket %li, new heap size %zu, heap location %zu",
+ b, c->heap_size, c->buckets[b].heap);
+ } else
+ heap_sift(c, c->buckets[b].heap);
+}
+
+static long heap_pop(struct cache_device *c)
+{
+ long ret = c->heap[0] - c->buckets;
+
+ if (!c->heap_size) {
+ printk(KERN_ERR "bcache: empty heap!");
+ return -1;
+ }
+
+ __inc_bucket_gen(c, ret);
+ smp_mb();
+ if (atomic_read(&c->heap[0]->pin)) {
+ pr_debug("priority %i bucket %li: not popping, pinned",
+ c->buckets[ret].priority, ret);
+ return -1;
+ }
+
+ heap_swap(c, 0, --c->heap_size);
+ heap_sift(c, 0);
+
+ c->heap[c->heap_size] = NULL;
+
+ pr_debug("priority %i bucket %li",
+ c->buckets[ret].priority, ret);
+
+ c->buckets[ret].priority = 0;
+ c->buckets[ret].heap = -1;
+ return ret;
+}
+
+static long pop_bucket(struct cache_device *c, uint16_t priority)
+{
+ long r;
+
+ while (!fifo_full(&c->free)) {
+ r = heap_pop(c);
+
+ if (r == -1)
+ break;
+
+ fifo_push(&c->free, r);
+
+ if (blk_queue_discard(bdev_get_queue(c->bdev))) {
+ spin_unlock(&c->bucket_lock);
+ /* should do this asynchronously */
+ blkdev_issue_discard(c->bdev, bucket_to_sector(c, r),
+ c->sb.bucket_size, GFP_NOIO, 0);
+ spin_lock(&c->bucket_lock);
+ }
+ }
+
+ if (!fifo_pop(&c->free, r))
+ r = -1;
+
+ if (r != -1)
+ c->buckets[r].priority = priority;
+
+ pr_debug("popping bucket %li prio %u", r, priority);
+ return r;
+}
+
+static void free_bucket_contents(struct cached_bucket *b)
+{
+ int i;
+
+ for (i = 0; i < pages_per_bucket(b); i++)
+ if (b->pages[i]) {
+ ClearPageDirty(b->pages[i]);
+ kunmap(b->pages[i]);
+ put_page(b->pages[i]);
+ b->pages[i] = NULL;
+ }
+#if 0
+ struct address_space *mapping = p[0]->mapping;
+
+ spin_lock_irq(&mapping->tree_lock);
+ for (i = 0; i < pages; i++)
+ __remove_from_page_cache(p[i]);
+ spin_unlock_irq(&mapping->tree_lock);
+#endif
+}
+
+static int fill_bucket(struct cached_bucket *b, struct search_context **s)
+{
+ struct cache_device *c = b->c;
+ int i, nread = 0, ret = 0;
+ struct bio *bio = NULL;
+ struct bio_list list;
+ bio_list_init(&list);
+
+ /*nread = find_get_pages(c->bdev->bd_inode->i_mapping,
+ (b->offset >> (PAGE_SHIFT - 9)),
+ pages_per_bucket(b), b->pages);*/
+
+ for (i = 0; i < pages_per_bucket(b); i++)
+ b->pages[i] = find_get_page(c->bdev->bd_inode->i_mapping,
+ b->offset / PAGE_SECTORS + i);
+
+ for (i = 0; i < pages_per_bucket(b); i++)
+ if (!b->pages[i]) {
+ b->pages[i] = __page_cache_alloc(GFP_NOIO);
+ b->pages[i]->mapping = c->bdev->bd_inode->i_mapping;
+ if (add_to_page_cache_lru(b->pages[i],
+ c->bdev->bd_inode->i_mapping,
+ b->offset / PAGE_SECTORS + i,
+ GFP_NOIO)) {
+ /* XXX: need to check for actual errors
+ * This code path should never happen anyways
+ * since fill_bucket is now called with write
+ * lock held on bucket
+ */
+ page_cache_release(b->pages[i]);
+ b->pages[i] = find_get_page(c->bdev->bd_inode->i_mapping,
+ b->offset / PAGE_SECTORS + i);
+ BUG_ON(!b->pages[i]);
+ goto wait;
+ }
+
+ unlock_page(b->pages[i]);
+
+ if (!bio) {
+ if (!(bio = bio_kmalloc(GFP_NOIO,
+ pages_per_bucket(b) - nread)))
+ goto err;
+
+ if (bio_list_empty(&list)) {
+ bio->bi_private = b;
+ bio->bi_end_io = fill_bucket_endio;
+ } else {
+ bio->bi_private = list.head;
+ bio->bi_end_io = bio_split_endio;
+ atomic_inc(&list.head->bi_remaining);
+ }
+ bio_list_add(&list, bio);
+
+ bio->bi_bdev = c->bdev;
+ bio->bi_sector = b->offset + i * PAGE_SECTORS;
+ }
+ nread++;
+
+ bio->bi_io_vec[bio->bi_vcnt].bv_page = b->pages[i];
+ bio->bi_io_vec[bio->bi_vcnt].bv_len = PAGE_SIZE;
+ bio->bi_io_vec[bio->bi_vcnt].bv_offset = 0;
+ bio->bi_vcnt++;
+ bio->bi_size += PAGE_SIZE;
+ data(b)[i] = kmap(b->pages[i]);
+ } else {
+wait: bio = NULL;
+ if (i == ret)
+ ret++;
+ data(b)[i] = kmap(b->pages[i]);
+ }
+
+ for (i = 0; i < pages_per_bucket(b); i++)
+ BUG_ON(b->offset + i * PAGE_SECTORS
+ != page_index(b->pages[i]) * PAGE_SECTORS);
+
+ atomic_set(&b->nread, ret);
+ submit_bio_list(READ, list.head);
+ return 0;
+err:
+ /* XXX: flag error on this bucket here */
+ return -1;
+}
+
+static void write_endio(struct bio *bio, int error)
+{
+ int i;
+ struct cache_device *c = bio->bi_private;
+ if (error) {
+ printk(KERN_ERR "bcache: write error");
+ c = c; /* flag error here */
+ }
+
+ for (i = 0; i < bio->bi_vcnt; i++)
+ put_page(bio->bi_io_vec[i].bv_page);
+
+ bio_put(bio);
+}
+
+static void __btree_write(struct cached_bucket *b, int skip,
+ int n, sector_t offset)
+{
+ int i;
+ struct cache_device *c = b->c;
+ struct bio *bio = NULL;
+
+ BUG_ON(n > pages_per_bucket(b));
+
+ for (i = skip; i < n; i++) {
+ if (!b->pages[i])
+ continue;
+
+ if (!b->pages[i] || !PageDirty(b->pages[i])) {
+ submit_bio_list(WRITE, bio);
+ bio = NULL;
+ continue;
+ }
+
+ BUG_ON(offset + i * PAGE_SECTORS
+ != page_index(b->pages[i]) * PAGE_SECTORS);
+
+ if (bio && bio->bi_vcnt >= 4) {
+ submit_bio_list(WRITE, bio);
+ bio = NULL;
+ }
+
+ if (!bio) {
+ if (!(bio = bio_kmalloc(GFP_NOIO, n - i))) {
+ pr_debug("couldn't allocate bio!");
+ return;
+ }
+
+ bio->bi_sector = page_index(b->pages[i]) * PAGE_SECTORS;
+ bio->bi_bdev = c->bdev;
+
+ bio->bi_end_io = write_endio;
+ bio->bi_private = c;
+ pr_debug("sector %llu pages %i",
+ (uint64_t) bio->bi_sector, n - i);
+ }
+
+ bio->bi_io_vec[bio->bi_vcnt].bv_page = b->pages[i];
+ bio->bi_io_vec[bio->bi_vcnt].bv_len = PAGE_SIZE;
+ bio->bi_io_vec[bio->bi_vcnt].bv_offset = 0;
+
+ bio->bi_size += PAGE_SIZE;
+ bio->bi_vcnt++;
+
+ get_page(b->pages[i]);
+ ClearPageDirty(b->pages[i]);
+ }
+
+ submit_bio_list(WRITE, bio);
+}
+
+static void btree_write(struct cached_bucket *b, int skip)
+{
+ int n = keys(&data(b)[skip]) / keys_per_page + 1;
+
+ if (((keys(&data(b)[skip]) + 1) % keys_per_page) == 0 &&
+ PageDirty(b->pages[skip]))
+ __btree_write(b, skip, n + skip, b->offset);
+}
+
+static bool ptr_bad(struct cached_bucket *b, struct btree_key *k)
+{
+ sector_t bucket = PTR_OFFSET(k);
+ long r = do_div(bucket, b->c->sb.bucket_size);
+
+ if (!k->key ||
+ (b->level && (PTR_SIZE(k) || r)) ||
+ (!b->level && !PTR_SIZE(k)))
+ return true;
+
+ if (bucket < b->c->sb.first_bucket ||
+ bucket >= b->c->sb.first_bucket + b->c->sb.nbuckets ||
+ PTR_SIZE(k) + r > b->c->sb.bucket_size)
+ return true;
+
+ return PTR_GEN(k) != sector_to_gen(b->c, PTR_OFFSET(k));
+}
+
+static void ptr_status(struct cached_bucket *b, struct btree_key *k, char *buf)
+{
+ sector_t bucket = PTR_OFFSET(k);
+ long r = do_div(bucket, b->c->sb.bucket_size);
+ uint8_t stale = 0;
+
+ *buf = 0;
+ if (bucket >= b->c->sb.first_bucket + b->c->sb.nbuckets)
+ sprintf(buf, "bad, offset past end of device");
+ if (bucket < b->c->sb.first_bucket)
+ sprintf(buf, "bad, short offset");
+ if (!PTR_OFFSET(k) ||
+ (!b->level && !PTR_SIZE(k)))
+ sprintf(buf, "zeroed key");
+ if (PTR_SIZE(k) + r > b->c->sb.bucket_size)
+ sprintf(buf, "bad, length too big");
+
+ if (!*buf)
+ stale = sector_to_gen(b->c, PTR_OFFSET(k)) - PTR_GEN(k);
+ if (stale)
+ sprintf(buf, "stale %i", stale);
+}
+
+struct cached_bucket *get_last_bucket_or_alloc(struct cache_device *c,
+ struct cached_bucket **n,
+ sector_t offset, int level,
+ int count, bool lru)
+{
+ struct cached_bucket *b;
+ sector_t old_offset = 0;
+
+ b = list_entry(c->lru.prev, struct cached_bucket, lru);
+ if (count >= c->btree_buckets_cached &&
+ atomic_read(&b->nread) == pages_per_btree &&
+ down_write_trylock(&b->lock)) {
+ BUG_ON(b->wait);
+ list_del(&b->lru);
+ old_offset = b->offset;
+ } else if (n && *n) {
+ b = *n, *n = NULL;
+ down_write_trylock(&b->lock);
+ } else {
+ spin_unlock(&c->bucket_lock);
+ b = kzalloc(sizeof(*b) + sizeof(void *) *
+ pages_per_btree * 2, GFP_NOIO);
+ if (!b)
+ return ERR_PTR(-ENOMEM);
+ init_rwsem(&b->lock);
+
+ if (n) {
+ *n = b;
+ return NULL;
+ }
+ spin_lock(&c->bucket_lock);
+ down_write_trylock(&b->lock);
+ }
+
+ b->offset = offset;
+ b->c = c;
+ b->level = level;
+ atomic_set(&b->nread, 0);
+
+ if (lru)
+ list_add(&b->lru, &c->lru);
+ else
+ INIT_LIST_HEAD(&b->lru);
+
+ spin_unlock(&c->bucket_lock);
+
+ if (old_offset)
+ __btree_write(b, 0, pages_per_btree, old_offset);
+ free_bucket_contents(b);
+
+ return b;
+}
+
+static struct cached_bucket *__get_bucket(struct cache_device *c,
+ sector_t offset, int level,
+ bool write, struct search_context **s)
+{
+ int i;
+ struct cached_bucket *b, *n = NULL;
+retry:
+ if (sector_to_priority(c, offset) != (uint16_t) ~0)
+ goto freed;
+
+ i = 0;
+ spin_lock(&c->bucket_lock);
+ list_for_each_entry(b, &c->lru, lru) {
+ if (offset == b->offset) {
+ list_move(&b->lru, &c->lru);
+ spin_unlock(&c->bucket_lock);
+
+ rw_lock(write, b);
+
+ if (offset == b->offset)
+ goto out;
+
+ rw_unlock(write, b);
+ goto retry;
+ }
+ i++;
+ }
+
+ b = get_last_bucket_or_alloc(c, &n, offset, level, i, true);
+ if (!b)
+ goto retry;
+ if (IS_ERR(b))
+ goto err;
+
+ if (fill_bucket(b, s)) {
+ /* fill bucket errors, those pages don't point to the right place */
+ rw_unlock(true, b);
+ run_wait_list(1, b->wait);
+ goto err;
+ }
+
+ if (!write)
+ downgrade_write(&b->lock);
+out:
+ if (IS_ERR(wait_search(atomic_read(&b->nread) == pages_per_bucket(b),
+ b->wait, *s))) {
+ rw_unlock(write, b);
+ goto err;
+ }
+
+ if (sector_to_priority(c, offset) == (uint16_t) ~0)
+ goto real_out;
+
+ rw_unlock(write, b);
+freed:
+ pr_debug("bucket %llu has been freed, gen %i, called from %p",
+ (uint64_t) offset, sector_to_gen(c, offset),
+ __builtin_return_address(1));
+ b = NULL;
+ goto real_out;
+err:
+ printk(KERN_WARNING "bcache: error allocating memory");
+ b = ERR_PTR(-ENOMEM);
+real_out:
+ kfree(n);
+ return b;
+}
+
+static struct cached_bucket *get_bucket(struct cached_bucket *b,
+ struct btree_key *k,
+ bool write, struct search_context **s)
+{
+ struct cached_bucket *r;
+ BUG_ON(!b->level);
+ r = __get_bucket(b->c, PTR_OFFSET(k), b->level - 1, write, s);
+ if (!r && !ptr_bad(b, k))
+ inc_gen(b->c, PTR_OFFSET(k));
+ return r;
+}
+
+static struct cached_bucket *upgrade_bucket(bool *w, struct cached_bucket *b,
+ struct search_context **s)
+{
+ int level = b->level;
+ sector_t offset = b->offset;
+
+ if (*w)
+ return b;
+ *w = true;
+
+ rw_unlock(false, b);
+ rw_lock(true, b);
+
+ if (sector_to_priority(b->c, b->offset) != (uint16_t) ~0) {
+ rw_unlock(true, b);
+ return NULL;
+ }
+
+ if (b->offset != offset) {
+ rw_unlock(true, b);
+ return __get_bucket(b->c, offset, level, true, s);
+ }
+ return b;
+}
+
+static void btree_free(struct cached_bucket *b, bool discard)
+{
+ struct cache_device *c = b->c;
+ long n = sector_to_bucket(c, b->offset);
+ BUG_ON(n < 0 || n > c->sb.nbuckets);
+ BUG_ON(b == c->root);
+
+ spin_lock(&c->bucket_lock);
+
+ __inc_bucket_gen(c, n);
+ smp_wmb();
+ c->buckets[n].priority = 0;
+
+ if (!fifo_push(&c->free, n))
+ heap_insert(c, n);
+
+ free_bucket_contents(b);
+
+ if (list_empty(&b->lru))
+ list_add(&b->lru, &c->lru);
+
+ spin_unlock(&c->bucket_lock);
+ run_wait_list(1, b->wait);
+
+ if (discard)
+ blkdev_issue_discard(c->bdev, b->offset,
+ c->sb.bucket_size, GFP_NOIO, 0);
+
+ pr_debug("bucket %li, sector %llu called from %p %p",
+ n, (uint64_t) b->offset,
+ __builtin_return_address(0),
+ __builtin_return_address(1));
+}
+
+static struct cached_bucket *btree_alloc(struct cache_device *c, int level,
+ struct btree_key *old[],
+ int nkeys, int skip, bool lru)
+{
+ long i = 0, bucket;
+ struct btree_node_header *h;
+ struct cached_bucket *b = NULL;
+ const char *err = "unable to alloc bucket";
+
+ spin_lock(&c->bucket_lock);
+ if ((bucket = pop_bucket(c, ~0)) == -1) {
+ spin_unlock(&c->bucket_lock);
+ goto err;
+ }
+
+ list_for_each_entry(b, &c->lru, lru)
+ i++;
+
+ b = get_last_bucket_or_alloc(c, NULL, bucket_to_sector(c, bucket),
+ level, i, lru);
+ if (IS_ERR_OR_NULL(b))
+ goto err;
+
+ err = "error adding new pages";
+ for (i = 0; i < pages_per_btree; i++) {
+ if (!(b->pages[i] =
+ find_or_create_page(c->bdev->bd_inode->i_mapping,
+ b->offset / PAGE_SECTORS + i,
+ GFP_NOIO)))
+ goto err;
+
+ unlock_page(b->pages[i]);
+ b->pages[i + pages_per_btree] = kmap(b->pages[i]);
+ }
+
+ atomic_set(&b->nread, pages_per_btree);
+
+ h = header(b);
+ get_random_bytes(&h->random, sizeof(uint64_t));
+ h->nkeys = nkeys - skip;
+
+ if (old)
+ for (i = 1; i <= h->nkeys; i++)
+ *node(data(b), i) = *node(old, i + skip);
+
+ for (i = 0; i < h->nkeys / keys_per_page + 1; i++)
+ SetPageDirty(b->pages[i]);
+
+ pr_debug("bucket %li, lru = %s, called from %p",
+ sector_to_bucket(c, b->offset),
+ lru ? "true" : "false",
+ __builtin_return_address(0));
+ return b;
+err:
+ printk(KERN_WARNING "bcache: btree_alloc: %s\n", err);
+ if (b) {
+ btree_free(b, false);
+ up_write(&b->lock);
+ } else if (bucket != -1) {
+ spin_lock(&c->bucket_lock);
+ c->buckets[bucket].priority = 0;
+ if (!fifo_push(&c->free, bucket))
+ heap_insert(c, bucket);
+ spin_unlock(&c->bucket_lock);
+ }
+ return NULL;
+}
+
+static void set_new_root(struct cached_bucket *b)
+{
+ struct bio *bio;
+ struct cache_device *c = b->c;
+ BUG_ON(sector_to_priority(c, b->offset) != (uint16_t) ~0);
+ BUG_ON(!header(b)->random);
+
+ spin_lock(&c->sb_lock);
+ c->sb.btree_level = b->level;
+ c->sb.btree_root = b->offset;
+ c->root = b;
+
+ bio = write_super(c);
+ spin_unlock(&c->sb_lock);
+ submit_bio_list(WRITE, bio);
+
+ pr_debug("new root %lli called from %p", c->sb.btree_root,
+ __builtin_return_address(0));
+}
+
+static void cache_hit(struct cache_device *c, struct bio *list)
+{
+ long b;
+ struct bio *bio, *p = NULL;
+
+ if (!list)
+ return;
+
+ spin_lock(&c->bucket_lock);
+ for (bio = list; bio; bio = bio->bi_next) {
+ bio->bi_bdev = c->bdev;
+
+ b = sector_to_bucket(c, bio->bi_sector);
+ BUG_ON(c->buckets[b].priority == (uint16_t) ~0);
+ c->buckets[b].priority = (long) initial_priority;
+ /* * (cache_hit_seek + cache_hit_priority
+ * bio_sectors(bio) / c->sb.bucket_size)
+ / (cache_hit_seek + cache_hit_priority);*/
+
+ if (c->buckets[b].heap != -1)
+ heap_sift(c, c->buckets[b].heap);
+
+ p = max(p, __rescale_heap(c, bio_sectors(bio)));
+ c->cache_hits++;
+ cache_hits++;
+ }
+ spin_unlock(&c->bucket_lock);
+
+ while (list) {
+ sector_t s = list->bi_sector;
+ bio = list;
+ list = bio->bi_next;
+ bio->bi_next = NULL;
+
+ __generic_make_request(bio);
+ atomic_dec(§or_to_struct(c, s)->pin);
+ }
+ submit_bio_list(WRITE, p);
+}
+
+static int next_good_key(struct btree_key **i, int j, struct cached_bucket *b)
+{
+ while (j <= keys(i) && ptr_bad(b, node(i, j)))
+ j++;
+ return j;
+}
+
+#define run_on_root(write, f, ...) ({ \
+ int _r = -2; \
+ do { \
+ struct cached_bucket *_b = c->root; \
+ bool _w = (write); \
+ rw_lock(_w, _b); \
+ if (sector_to_priority(c, _b->offset) == (uint16_t) ~0 &&\
+ _b->level == c->sb.btree_level && \
+ _w == (write)) { \
+ _r = f(_b, __VA_ARGS__); \
+ smp_mb(); \
+ } else { \
+ rw_unlock(_w, _b); \
+ cpu_relax(); \
+ } \
+ } while (_r == -2); \
+ _r; })
+
+#define sorted_set_checks(i, b) ({ \
+ bool _cont = true; \
+ if (index(i, b) >= pages_per_bucket(b)) \
+ _cont = false; \
+ else if (index(i, b) >= nread) \
+ goto again; \
+ else if (rand(i) != header(b)->random) \
+ _cont = false; \
+ else if (keys(i) >= (pages_per_bucket(b) - index(i, b)) * keys_per_page) {\
+ printk(KERN_DEBUG "bcache: bad btree header: page %i, %i keys",\
+ index(i, b), keys(i)); \
+ keys(i) = 0; \
+ if (i != data(b)) \
+ _cont = false; \
+ } else if (keys(i) >= (nread - index(i, b)) * keys_per_page) \
+ goto again; \
+ _cont; })
+
+/* Iterate over the sorted sets of pages
+ */
+#define for_each_sorted_set(i, b) \
+ for (i = data(b), nread = atomic_read(&b->nread); \
+ sorted_set_checks(i, b); \
+ i += keys(i) / keys_per_page + 1)
+
+#define for_each_key(i, j, b) \
+ for_each_sorted_set(i, b) \
+ for (j = 1; j <= keys(i); j++)
+
+void dump_bucket_and_panic(struct cached_bucket *b)
+{
+ int j, nread;
+ struct btree_key **i;
+
+ for_each_key(i, j, b) {
+ char buf[30];
+ ptr_status(b, node(i, j), buf);
+ printk(KERN_ERR "page %i key %i/%i: "
+ "key %llu -> offset %llu len %i gen %i bucket %li %s",
+ index(i, b), j, keys(i), node(i, j)->key,
+ PTR_OFFSET(node(i, j)), PTR_SIZE(node(i, j)),
+ PTR_GEN(node(i, j)),
+ sector_to_bucket(b->c, PTR_OFFSET(node(i, j))),
+ buf);
+ }
+again:
+ panic("at offset %llu", (uint64_t) b->offset);
+}
+
+/*
+ * Returns the smallest key greater than the search key.
+ * This is because we index by the end, not the beginning
+ */
+static int btree_bsearch(struct btree_key *i[], uint64_t search)
+{
+ int l = 1, r = keys(i) + 1;
+
+ while (l < r) {
+ int j = (l + r) >> 1;
+ if (node(i, j)->key > search)
+ r = j;
+ else
+ l = j + 1;
+ }
+
+ BUG_ON(l <= keys(i) && search >= node(i, l)->key);
+ return l;
+}
+
+#define do_fixup(_front, _len, _key) ({ \
+ struct btree_key _old = *_key; \
+ if (_front) \
+ _key->ptr += TREE_PTR(0, 0, _len); \
+ else \
+ _key->key -= _len; \
+ _key->ptr -= TREE_PTR(0, min(_len, PTR_SIZE(_key)), 0); \
+ \
+ pr_debug("fixing up %s of %llu -> %llu len %i by %i sectors: " \
+ "now %llu -> %llu len %i", _front ? "front" : "back", \
+ _old.key, PTR_OFFSET(&_old), PTR_SIZE(&_old), _len, \
+ _key->key, PTR_OFFSET(_key), PTR_SIZE(_key)); })
+
+static void fixup_old_keys(struct cached_bucket *b, struct btree_key *end[], struct btree_key *k)
+{
+ struct btree_key **i;
+ int nread = pages_per_bucket(b);
+
+ if (b->level)
+ return;
+
+ for (i = data(b);
+ i < end && sorted_set_checks(i, b);
+ i += keys(i) / keys_per_page + 1) {
+ int m = btree_bsearch(i, k->key);
+
+ do {
+ int front = KEY_OVERLAP(k, node(i, m));
+ int back = KEY_OVERLAP(node(i, m), k);
+
+ if (m > keys(i))
+ continue;
+
+ if (node(i, m)->key <= k->key - PTR_SIZE(k))
+ break;
+
+ if (k->key - PTR_SIZE(k) < node(i, m)->key &&
+ front > 0)
+ do_fixup(true, front, node(i, m));
+ else if (node(i, m)->key - PTR_SIZE(node(i, m)) < k->key &&
+ back > 0)
+ do_fixup(false, back, node(i, m));
+ } while (--m);
+ }
+ label(again, BUG());
+}
+
+static void fill_bucket_endio(struct bio *bio, int error)
+{
+ /* XXX: flag error here
+ */
+ struct cached_bucket *b = bio->bi_private;
+ struct btree_key **i;
+ int j, nread = pages_per_bucket(b);
+
+ BUG_ON(error);
+
+ for (i = data(b);
+ sorted_set_checks(i, b);
+ i += keys(i) / keys_per_page + 1)
+ if (i != data(b))
+ for (j = 1; j <= keys(i); j++)
+ fixup_old_keys(b, i, node(i, j));
+
+ label(again, BUG());
+ atomic_set(&b->nread, pages_per_bucket(b));
+ run_wait_list(1, b->wait);
+ bio_put(bio);
+}
+
+static int btree_search(struct cached_bucket *b, int device, struct bio *bio,
+ struct search_context **s)
+{
+ int ret = -1, j, nread;
+ struct btree_key **i, **reverse;
+ uint64_t orig, search = TREE_KEY(device, bio->bi_sector);
+
+ do {
+ orig = search;
+ for_each_sorted_set(reverse, b)
+ ;
+ do {
+ for_each_sorted_set(i, b)
+ if (i + keys(i) / keys_per_page + 1 == reverse)
+ break;
+ reverse = i;
+
+ for (j = btree_bsearch(i, search); j <= keys(i); j++) {
+ int len = node(i, j)->key - search;
+ struct bio *split;
+
+ if (ptr_bad(b, node(i, j)) ||
+ search >= node(i, j)->key)
+ continue;
+
+ pr_debug("page %i key %i/%i: "
+ "key %llu -> offset %llu len %i gen %i",
+ index(i, b), j, keys(i), node(i, j)->key,
+ PTR_OFFSET(node(i, j)), PTR_SIZE(node(i, j)),
+ PTR_GEN(node(i, j)));
+
+ if (search < node(i, j)->key - PTR_SIZE(node(i, j)))
+ break;
+
+ atomic_inc(&PTR_BUCKET(b->c, node(i, j))->pin);
+ smp_mb__after_atomic_inc();
+
+ if (sector_to_gen(b->c, PTR_OFFSET(node(i, j)))
+ != PTR_GEN(node(i, j))) {
+ atomic_dec(&PTR_BUCKET(b->c, node(i, j))->pin);
+ continue;
+ }
+
+ if (sector_to_priority(b->c, PTR_OFFSET(node(i, j))) == (uint16_t) ~0) {
+ printk(KERN_ERR "\nBad priority! page %i key %i:\n", index(i, b), j);
+ dump_bucket_and_panic(b);
+ }
+
+ if (!(split = bio_split_front(bio, len, NULL)))
+ goto err;
+
+ split->bi_sector += PTR_SIZE(node(i, j))
+ - KEY_OFFSET(node(i, j))
+ + PTR_OFFSET(node(i, j));
+
+ pr_debug("cache hit of %i sectors from %llu, need %i sectors",
+ bio_sectors(split), (uint64_t) split->bi_sector,
+ split == bio ? 0 : bio_sectors(bio));
+
+ if (split != bio) {
+ split->bi_next = bio->bi_next;
+ bio->bi_next = split;
+ } else
+ goto done;
+
+ search = TREE_KEY(device, bio->bi_sector);
+ }
+ } while (i != data(b));
+ } while (search != orig);
+
+ label(err, ret = -1);
+ label(again, ret = 0);
+ label(done, ret = 1);
+ rw_unlock(false, b);
+ return ret;
+}
+
+static int btree_search_recurse(struct cached_bucket *b, int device,
+ struct bio *bio, struct search_context **s)
+{
+ int ret = -1, j, nread;
+ struct btree_key **i, recurse_key;
+
+ do {
+ uint64_t search = TREE_KEY(device, bio->bi_sector);
+ struct cached_bucket *r;
+ recurse_key.key = ~0;
+
+ pr_debug("level %i bucket %li searching for %llu",
+ b->level, sector_to_bucket(b->c, b->offset), search);
+
+ if (!b->level)
+ return btree_search(b, device, bio, s);
+
+ for_each_sorted_set(i, b) {
+ j = btree_bsearch(i, search);
+
+ while (j <= keys(i) &&
+ (ptr_bad(b, node(i, j)) ||
+ search >= node(i, j)->key))
+ j++;
+
+ if (j <= keys(i) &&
+ recurse_key.key > node(i, j)->key)
+ recurse_key = *node(i, j);
+ }
+
+ if (recurse_key.key == ~0)
+ break;
+
+ r = get_bucket(b, &recurse_key, false, s);
+ if (IS_ERR_OR_NULL(r))
+ goto err;
+
+ ret = max(ret, btree_search_recurse(r, device, bio, s));
+ } while (ret < 1 && recurse_key.key == TREE_KEY(device, bio->bi_sector));
+
+ label(err, ret = -1);
+ label(again, ret = 0);
+ rw_unlock(false, b);
+ return ret;
+}
+
+static void btree_sort(struct btree_key **base, size_t num)
+{
+ size_t i;
+
+ void sift(size_t r, size_t n)
+ {
+ int c = r * 2;
+ for (; c <= n; r = c, c *= 2) {
+ if (c < n &&
+ node(base, c)->key < node(base, c + 1)->key)
+ c++;
+ if (node(base, r)->key >= node(base, c)->key)
+ return;
+ swap(*node(base, r), *node(base, c));
+ }
+ }
+
+ for (i = num / 2 + 1; i > 0; --i)
+ sift(i, num);
+
+ for (i = num; i > 1; sift(1, --i))
+ swap(*node(base, 1), *node(base, i));
+}
+
+static bool btree_merge_key(struct cached_bucket *b, struct btree_key *i[],
+ size_t *j, struct btree_key *k)
+{
+ bool ret = false;
+ BUG_ON(!k->key);
+
+ while (1) {
+ if (*j <= keys(i) &&
+ !b->level &&
+ !ptr_bad(b, node(i, *j))) {
+ int len = KEY_OVERLAP(k, node(i, *j));
+
+ if (len == 0 && PTR_OFFSET(node(i, *j)) ==
+ PTR_OFFSET(k) + PTR_SIZE(k) &&
+ sector_to_bucket(b->c, PTR_OFFSET(k)) ==
+ sector_to_bucket(b->c, PTR_OFFSET(node(i, *j)))) {
+ k->key += PTR_SIZE(node(i, *j));
+ k->ptr += TREE_PTR(0, PTR_SIZE(node(i, *j)), 0);
+ goto merge;
+ }
+
+ if (len > 0)
+ do_fixup(true, len, node(i, *j));
+ }
+
+ if (--(*j) && !b->level) {
+ int len = KEY_OVERLAP(node(i, *j), k);
+
+ if (ptr_bad(b, node(i, *j)) ||
+ len >= PTR_SIZE(node(i, *j)))
+ goto merge;
+
+ if (len == 0 && PTR_OFFSET(k) ==
+ PTR_OFFSET(node(i, *j)) + PTR_SIZE(node(i, *j)) &&
+ sector_to_bucket(b->c, PTR_OFFSET(k)) ==
+ sector_to_bucket(b->c, PTR_OFFSET(node(i, *j)))) {
+ k->ptr += TREE_PTR(0, PTR_SIZE(node(i, *j)), 0);
+ k->ptr -= TREE_PTR(0, 0, PTR_SIZE(node(i, *j)));
+ goto merge;
+ }
+
+ if (len > 0)
+ do_fixup(false, len, node(i, *j));
+ } else if (*j)
+ if (PTR_OFFSET(node(i, *j)) == PTR_OFFSET(k))
+ goto merge;
+ (*j)++;
+ return ret;
+merge:
+ node(i, *j)->ptr -= TREE_PTR(0, PTR_SIZE(node(i, *j)), 0);
+ node(i, *j)->key = k->key;
+
+ pr_debug("new key %llu len %i old key %llu len %i",
+ KEY_OFFSET(k), PTR_SIZE(k), KEY_OFFSET(node(i, *j)), PTR_SIZE(node(i, *j)));
+ ret = true;
+ }
+}
+
+static void btree_clean(struct cached_bucket *b, uint64_t smallest)
+{
+ size_t j, k, n, nread;
+ int orig = 0, nkeys = header(b)->nkeys;
+ struct btree_node_header *h;
+ struct btree_key **i;
+
+ bool bad(struct btree_key *k)
+ {
+ int len = smallest - (k->key - PTR_SIZE(k));
+ if (len > 0)
+ do_fixup(true, len, k);
+ return ptr_bad(b, k);
+ }
+
+ for (h = header(b), i = data(b);
+ i < data(b) + pages_per_bucket(b) &&
+ h->random == header(b)->random;
+ i += (n / keys_per_page) + 1,
+ h = (struct btree_node_header *) *i) {
+ if (h->nkeys >= (pages_per_bucket(b) - index(i, b)) * keys_per_page) {
+ printk(KERN_DEBUG "bcache: bad btree header: page %i, %i keys",
+ index(i, b), keys(i));
+ keys(i) = 0;
+ break;
+ }
+
+ orig += n = h->nkeys;
+
+ if (data(b) == i)
+ for (j = 1; j <= nkeys; j++)
+ while ((bad(node(i, j))) && j <= --nkeys)
+ *node(data(b), j) = *node(i, nkeys + 1);
+ else
+ for (j = 1, k = 1; j <= n; j++) {
+ if (bad(node(i, j)))
+ continue;
+
+ while (k <= header(b)->nkeys &&
+ node(data(b), k)->key <= node(i, j)->key)
+ k++;
+
+ if (btree_merge_key(b, data(b), &k, node(i, j)))
+ *node(data(b), k) = *node(i, j);
+ else
+ *node(data(b), ++nkeys) = *node(i, j);
+ }
+
+ header(b)->nkeys = nkeys;
+ btree_sort(data(b), nkeys);
+ }
+
+ get_random_bytes(&header(b)->random, sizeof(uint64_t));
+ n = 0;
+ for_each_key(i, j, b)
+ if (ptr_bad(b, node(i, j)))
+ n++;
+again:
+ pr_debug("merged %i keys from %i keys, %zu now bad",
+ header(b)->nkeys, orig, n);
+}
+
+static int btree_gc(struct cached_bucket *b, struct btree_key *root,
+ uint64_t smallest, struct search_context **s)
+{
+ int j, ret = 0, nread;
+ struct cache_device *c = b->c;
+ struct btree_key **i;
+ struct cached_bucket *n = NULL, *r;
+ uint64_t last = 0;
+
+ for_each_key(i, j, b)
+ if (PTR_OFFSET(node(i, j)) >=
+ c->sb.bucket_size * c->sb.first_bucket &&
+ PTR_OFFSET(node(i, j)) <
+ c->sb.bucket_size * (c->sb.first_bucket + c->sb.nbuckets))
+ ret = max_t(uint8_t, ret,
+ sector_to_gen(c, PTR_OFFSET(node(i, j))) -
+ PTR_GEN(node(i, j)));
+
+ if (!PageDirty(b->pages[0]) && ret > 10)
+ n = btree_alloc(c, b->level, NULL, 0, 0,
+ c->sb.btree_level != b->level);
+
+ if (n) {
+ for (j = 0; j < pages_per_bucket(b); j++)
+ memcpy(data(n)[j], data(b)[j], PAGE_SIZE);
+ swap(b, n);
+ }
+
+ if (PageDirty(b->pages[0])) {
+ btree_clean(b, smallest);
+ *root = bucket_key(b);
+ ret = 0;
+ } else if (b->level)
+ goto again;
+
+ for_each_key(i, j, b) {
+ long bucket;
+ struct bucket_gc *g;
+ if (ptr_bad(b, node(i, j)))
+ continue;
+
+ bucket = sector_to_bucket(c, PTR_OFFSET(node(i, j)));
+ g = &c->garbage[bucket];
+
+ if (g->mark == 3)
+ continue;
+
+ if (g->mark == (b->level ? 1 : 2)) {
+ printk(KERN_WARNING "bcache: btree and data pointers to same bucket %li, priority %i: "
+ "level %i key %llu -> offset %llu len %i",
+ bucket, c->buckets[bucket].priority, b->level, node(i, j)->key,
+ PTR_OFFSET(node(i, j)), PTR_SIZE(node(i, j)));
+ g->mark = 3;
+ } else if (b->level) {
+ uint64_t t = node(i, j)->key;
+ r = get_bucket(b, node(i, j), true, s);
+
+ if (IS_ERR_OR_NULL(r))
+ continue;
+
+ ret = max_t(uint8_t, ret,
+ btree_gc(r, node(i, j), last, s));
+ last = t;
+ g->mark = 2;
+ } else
+ g->mark = 1;
+ }
+
+ if (b->level)
+ btree_clean(b, 0);
+
+ __btree_write(b, 0, atomic_read(&b->nread), b->offset);
+
+again:
+ rw_unlock(true, b);
+ if (n) {
+ if (c->sb.btree_level == b->level)
+ set_new_root(b);
+
+ btree_free(n, true);
+ rw_unlock(true, n);
+ }
+ return ret;
+}
+
+static void do_btree_gc(struct work_struct *w)
+{
+ long i;
+ struct btree_key root;
+ struct cache_device *c = container_of(w, struct cache_device, work);
+ struct search_context s, *sp = &s;
+ memset(&s, 0, sizeof(s));
+ s.flags |= SEARCH_BLOCK;
+
+ i = run_on_root(true, btree_gc, &root, 0, &sp);
+
+ spin_lock(&c->bucket_lock);
+ c->garbage[sector_to_bucket(c, c->root->offset)].mark = 2;
+ c->need_gc = i;
+
+ for (i = 0; i < c->sb.nbuckets; i++) {
+ c->buckets[i].last_gc = c->garbage[i].gen;
+ c->need_gc = max_t(uint8_t, c->need_gc,
+ c->buckets[i].gen -
+ c->buckets[i].last_gc);
+ switch (c->garbage[i].mark) {
+#if 0
+ case 2:
+ if (c->buckets[i].priority == (uint16_t) ~0)
+ break;
+ case 1:
+ if (c->buckets[i].priority != (uint16_t) ~0)
+ break;
+ __inc_bucket_gen(c, i);
+ case 0:
+#endif
+ case 3:
+ pr_debug("mark and sweep found free bucket %li", i);
+ c->buckets[i].priority = 0;
+ c->buckets[i].gen++;
+ heap_insert(c, i);
+ }
+ }
+
+ pr_debug("garbage collect done, new need_gc %i", c->need_gc);
+ spin_unlock(&c->bucket_lock);
+ up(&c->gc_lock);
+}
+
+static void btree_insert_one_key(struct cached_bucket *b, struct btree_key *i[],
+ struct btree_key *k)
+{
+ size_t j, m;
+ const char *s = "replacing";
+
+ BUG_ON(PTR_GEN(k) == sector_to_gen(b->c, PTR_OFFSET(k)) &&
+ ((b->level != 0) ^
+ (sector_to_priority(b->c, PTR_OFFSET(k)) == (uint16_t) ~0)));
+ BUG_ON((b->level != 0) ^ !PTR_SIZE(k));
+
+ fixup_old_keys(b, i, k);
+ m = btree_bsearch(i, k->key);
+
+ if (!btree_merge_key(b, i, &m, k)) {
+ s = "inserting";
+ if (b->level)
+ k->ptr = TREE_PTR(inc_gen(b->c, PTR_OFFSET(k)),
+ 0, PTR_OFFSET(k));
+
+ for (j = keys(i)++; j >= m; --j)
+ *node(i, j + 1) = *node(i, j);
+ }
+
+ *node(i, m) = *k;
+
+ pr_debug("%s at %llu level %i page %i key %zu/%i: "
+ "key %llu ptr %llu len %i",
+ s, (uint64_t) b->offset, b->level, index(i, b), m, keys(i),
+ KEY_OFFSET(k), PTR_OFFSET(k), PTR_SIZE(k));
+
+ SetPageDirty(virt_to_page(i[keys(i) / keys_per_page]));
+}
+
+static int btree_split(struct cached_bucket *b,
+ struct btree_key *new_keys, int *n)
+{
+ int ret = 0;
+ struct cache_device *c = b->c;
+ struct cached_bucket *n1, *n2 = NULL, *n3 = NULL;
+ struct btree_node_header *h;
+ bool root = (c->sb.btree_level == b->level);
+
+ h = header(b);
+ pr_debug("splitting at level %i of %i sector %llu nkeys %i",
+ b->level, c->sb.btree_level, (uint64_t) b->offset, h->nkeys);
+ btree_clean(b, 0);
+
+ if (h->nkeys < keys_per_page * pages_per_bucket(b) / 2) {
+ pr_debug("not splitting: %i keys", h->nkeys);
+
+ if (!(n1 = btree_alloc(c, b->level, data(b), h->nkeys, 0, !root)))
+ goto err;
+
+ while (*n)
+ btree_insert_one_key(n1, data(n1), &new_keys[--(*n)]);
+
+ btree_write(n1, 0);
+
+ rw_unlock(true, n1);
+ if (root)
+ set_new_root(n1);
+ else
+ new_keys[(*n)++] = bucket_key(n1);
+ goto out;
+ }
+
+ if (!(n1 = btree_alloc(c, b->level, data(b), h->nkeys >> 1, 0, true)) ||
+ !(n2 = btree_alloc(c, b->level, data(b), h->nkeys, h->nkeys >> 1, true)))
+ goto err;
+
+ while (*n)
+ if (new_keys[--(*n)].key <= last_key(data(n1)))
+ btree_insert_one_key(n1, data(n1), &new_keys[*n]);
+ else
+ btree_insert_one_key(n1, data(n2), &new_keys[*n]);
+
+ new_keys[(*n)++] = bucket_key(n2);
+ new_keys[(*n)++] = bucket_key(n1);
+
+ btree_write(n1, 0);
+ btree_write(n2, 0);
+
+ rw_unlock(true, n2);
+ rw_unlock(true, n1);
+ n1 = n2 = NULL;
+
+ if (root) {
+ if (!(n3 = btree_alloc(c, b->level + 1, NULL, 0, 0, false)))
+ goto err;
+
+ while (*n)
+ btree_insert_one_key(n3, data(n3), &new_keys[--(*n)]);
+ btree_write(n3, 0);
+
+ rw_unlock(true, n3);
+ set_new_root(n3);
+ }
+out:
+ btree_free(b, true);
+ return ret;
+err:
+ printk(KERN_WARNING "bcache: couldn't split");
+ if (n2) {
+ btree_free(n2, false);
+ rw_unlock(true, n2);
+ }
+ if (n1) {
+ btree_free(n1, false);
+ rw_unlock(true, n1);
+ }
+ btree_write(b, 0);
+ return 0;
+}
+
+static int btree_insert(struct cached_bucket *b, struct btree_key *new_keys,
+ int *n, struct search_context **s)
+{
+ int ret = 0, sets = 0, nread;
+ uint64_t biggest = 0;
+ struct btree_key **i;
+
+ while (*n) {
+ sets = 0;
+ for_each_sorted_set(i, b) {
+ sets++;
+ if (keys(i))
+ biggest = max(biggest, last_key(i));
+
+ if (PageDirty(b->pages[index(i, b)]))
+ break;
+ }
+
+ if (index(i, b) >= pages_per_bucket(b) ||
+ (rand(i) == header(b)->random &&
+ keys(i) + 1 >= (pages_per_bucket(b) - index(i, b)) * keys_per_page))
+ return btree_split(b, new_keys, n);
+
+ if (rand(i) != header(b)->random) {
+ rand(i) = header(b)->random;
+ keys(i) = 0;
+ SetPageDirty(b->pages[index(i, b)]);
+ }
+
+ while (*n && (keys(i) + 1) % keys_per_page) {
+ btree_insert_one_key(b, i, &new_keys[--(*n)]);
+
+ if (new_keys[*n].key > biggest)
+ ret = 1;
+
+ biggest = max(new_keys[*n].key, biggest);
+ }
+
+ btree_write(b, index(i, b));
+ }
+ new_keys[0].ptr = bucket_to_ptr(b);
+ new_keys[0].key = biggest;
+ *n = ret;
+
+ if (sets > 3) {
+ struct cached_bucket *clean =
+ btree_alloc(b->c, b->level, NULL, 0, 0,
+ b->c->sb.btree_level != b->level);
+ if (clean) {
+ int j;
+ *n = 1;
+ for (j = 0; j < pages_per_bucket(b); j++)
+ memcpy(data(clean)[j], data(b)[j], PAGE_SIZE);
+
+ btree_clean(clean, 0);
+
+ if (b->c->sb.btree_level == b->level)
+ set_new_root(clean);
+ new_keys[0] = bucket_key(clean);
+ rw_unlock(true, clean);
+
+ btree_free(b, true);
+ }
+ }
+
+ label(again, ret = -1);
+ return ret;
+}
+
+static int btree_insert_recurse(struct cached_bucket *b, int *level,
+ struct btree_key *new_keys, int *n,
+ struct search_context **s)
+{
+ int j, ret = 0, nread;
+ struct cached_bucket *r;
+ bool write = !(b->level - *level);
+
+ if (!atomic_read(&b->nread))
+ goto again;
+
+ if (!header(b)->random) {
+ printk(KERN_WARNING "bcache: btree was trashed, bucket %li, level %i, h->nkeys %i\n",
+ sector_to_bucket(b->c, b->offset), b->level, header(b)->nkeys);
+trashed:
+ if (b->c->sb.btree_level == b->level) {
+ dump_bucket_and_panic(b);
+
+ if (!(r = btree_alloc(b->c, 0, NULL, 0, 0, false)))
+ goto done;
+ set_new_root(r);
+
+ btree_free(b, true);
+ rw_unlock(write, b);
+
+ b = r;
+ write = true;
+ } else
+ btree_free(b, true);
+
+ goto retry;
+ }
+
+ if (b->level > *level) {
+ uint64_t search = new_keys->key - PTR_SIZE(new_keys);
+ struct btree_key **i, recurse_key = { .key = 0, .ptr = 0 };
+
+ for_each_sorted_set(i, b) {
+ j = btree_bsearch(i, search);
+ j = next_good_key(i, j, b);
+
+ while (j && (j > keys(i) || ptr_bad(b, node(i, j))))
+ --j;
+
+ /* Pick the smallest key to recurse on that's bigger
+ * than the key we're inserting, or failing that,
+ * the biggest key.
+ */
+ if (j &&
+ ((node(i, j)->key > recurse_key.key &&
+ (recurse_key.key < search || !search)) ||
+ (node(i, j)->key < recurse_key.key &&
+ node(i, j)->key > search)))
+ recurse_key = *node(i, j);
+ }
+
+ /* No key to recurse on */
+ if (!recurse_key.ptr) {
+ printk(KERN_WARNING "no key to recurse on trying to insert %llu at level %i of %i\n",
+ new_keys->key, b->level, b->c->sb.btree_level);
+ goto trashed;
+ }
+
+ r = get_bucket(b, &recurse_key, !(b->level - *level - 1), s);
+ if (!r)
+ goto retry;
+ if (IS_ERR(r))
+ goto err;
+
+ pr_debug("recursing on %llu to insert %llu %s",
+ recurse_key.key, new_keys->key,
+ new_keys->key > recurse_key.key ? "embiggening" : "");
+
+ BUG_ON(!*n);
+ BUG_ON((*level != 0) ^ !PTR_SIZE(new_keys));
+ BUG_ON(PTR_GEN(new_keys) == sector_to_gen(b->c, PTR_OFFSET(new_keys)) &&
+ ((*level != 0) ^ (sector_to_priority(b->c, PTR_OFFSET(new_keys)) == (uint16_t) ~0)));
+
+ ret = btree_insert_recurse(r, level, new_keys, n, s);
+
+ if (*n && ret >= 0) {
+ BUG_ON(PTR_SIZE(new_keys));
+ BUG_ON(PTR_GEN(new_keys) == sector_to_gen(b->c, PTR_OFFSET(new_keys)) &&
+ sector_to_priority(b->c, PTR_OFFSET(new_keys)) != (uint16_t) ~0);
+ }
+ }
+
+ if (*n && ret >= 0) {
+ *level = b->level;
+ if (!(b = upgrade_bucket(&write, b, s))) {
+ printk(KERN_DEBUG "retrying upgrade\n");
+ goto retry;
+ }
+ if (IS_ERR(b))
+ goto err;
+ ret = btree_insert(b, new_keys, n, s);
+ }
+
+ if (*n && ret >= 0) {
+ BUG_ON(PTR_SIZE(new_keys));
+ BUG_ON(PTR_GEN(new_keys) == sector_to_gen(b->c, PTR_OFFSET(new_keys)) &&
+ sector_to_priority(b->c, PTR_OFFSET(new_keys)) != (uint16_t) ~0);
+ }
+done:
+ label(err, ret = -3);
+ label(retry, ret = -2);
+ label(again, ret = -1);
+ if (!IS_ERR_OR_NULL(b))
+ rw_unlock(write, b);
+ return ret;
+}
+
+static void btree_insert_async(struct search_context *s)
+{
+ struct cache_device *c = s->q;
+ int ret;
+
+ while (s->nkeylist) {
+ if (!s->nkeys) {
+ s->new_keys[0] = s->keylist[--s->nkeylist];
+ s->level = 0;
+ s->nkeys = 1;
+ }
+
+ ret = run_on_root(!(_b->level - s->level),
+ btree_insert_recurse, &s->level,
+ s->new_keys, &s->nkeys, &s);
+
+ if (ret == -3)
+ printk(KERN_WARNING "bcache: out of memory trying to insert key\n");
+
+ if (ret == -1)
+ return_f(s, btree_insert_async);
+ s->nkeys = 0;
+ }
+
+ if (s->keylist != &s->new_keys[0])
+ kfree(s->keylist);
+
+ return_f(s, s->parent);
+}
+
+static struct open_bucket *get_open_bucket(uint64_t key,
+ struct task_struct *task)
+{
+ long i = 0;
+ struct open_bucket *b;
+
+ spin_lock(&open_bucket_lock);
+ list_for_each_entry(b, &open_buckets, list) {
+ if (b->cache &&
+ (b->key.key == key || b->last == task))
+ goto out;
+ i++;
+ }
+
+ if (i < 8) {
+ spin_unlock(&open_bucket_lock);
+ b = kzalloc(sizeof(struct open_bucket), GFP_NOIO);
+ spin_lock(&open_bucket_lock);
+
+ if (!b)
+ goto err;
+ INIT_LIST_HEAD(&b->list);
+ } else
+ b = list_entry(open_buckets.prev, struct open_bucket, list);
+
+out:
+ if (!b->cache ||
+ b->gen != sector_to_gen(b->cache, b->offset)) {
+ struct cache_device *c;
+ list_for_each_entry(c, &cache_devices, list)
+ if (!b->cache ||
+ (b->cache->heap[0] && c->heap[0] &&
+ b->cache->heap[0]->priority > c->heap[0]->priority))
+ b->cache = c;
+
+ if (!b->cache)
+ goto err;
+
+ spin_lock(&b->cache->bucket_lock);
+ i = pop_bucket(b->cache, initial_priority);
+ if (i == -1) {
+ b->cache = NULL;
+ spin_unlock(&b->cache->bucket_lock);
+ goto err;
+ }
+
+ spin_unlock(&b->cache->bucket_lock);
+
+ b->offset = bucket_to_sector(b->cache, i);
+ b->sectors_free = b->cache->sb.bucket_size;
+ b->gen = sector_to_gen(b->cache, b->offset);
+ }
+
+ b->last = task;
+ b->key.key = key;
+
+ list_move(&b->list, &open_buckets);
+ return b;
+err:
+ spin_unlock(&open_bucket_lock);
+ return NULL;
+}
+
+static void close_open_bucket(struct open_bucket *b,
+ struct btree_key *insert_key, int split)
+{
+ struct bio *bio = NULL;
+ BUG_ON(!split);
+
+ b->key.key += TREE_KEY(0, split);
+
+ insert_key->key = TREE_KEY(lookup_id(b->cache, KEY_DEV(&b->key)),
+ KEY_OFFSET(&b->key)),
+ insert_key->ptr = TREE_PTR(b->gen, split,
+ b->offset + b->cache->sb.bucket_size -
+ b->sectors_free);
+
+ b->sectors_free -= split;
+ b->cache->sectors_written += split;
+
+ if (b->sectors_free < PAGE_SECTORS) {
+ spin_lock(&b->cache->bucket_lock);
+ heap_insert(b->cache, sector_to_bucket(b->cache, b->offset));
+ bio = __rescale_heap(b->cache, b->cache->sb.bucket_size);
+ spin_unlock(&b->cache->bucket_lock);
+
+ b->cache = NULL;
+ list_move_tail(&b->list, &open_buckets);
+ }
+ spin_unlock(&open_bucket_lock);
+ submit_bio_list(WRITE, bio);
+}
+
+static void bio_insert_endio(struct bio *bio, int error)
+{
+ struct search_context *s = bio->bi_private;
+ bio_put(bio);
+
+ if (error)
+ BUG();
+ else
+ return_f(s, btree_insert_async);
+}
+
+static const char *bio_insert(struct task_struct *task, struct bio *bio,
+ struct search_context *s)
+{
+ int split, id = bio->bi_bdev->bd_cache_identifier;
+ struct bio *n;
+ const char *ret;
+ s->keylist = &s->new_keys[0];
+
+ bio->bi_private = s;
+ bio->bi_end_io = bio_insert_endio;
+
+ do {
+ struct cache_device *c;
+ struct open_bucket *b;
+ struct btree_key *k;
+
+ if (is_power_of_2(s->nkeylist)) {
+ ret = "out of memory";
+ if (!(s->keylist =
+ krealloc(s->nkeylist == 1 ? NULL : s->keylist,
+ sizeof(*s->keylist) * s->nkeylist << 1,
+ GFP_NOIO)))
+ goto err;
+
+ if (s->nkeylist == 1)
+ memcpy(s->keylist, s->new_keys, sizeof(*s->keylist) * 2);
+ }
+
+ ret = "get_open_bucket error";
+ if (!(b = get_open_bucket(TREE_KEY(id, bio->bi_sector), task)))
+ goto err;
+
+ s->q = c = b->cache;
+ split = min(min(bio_sectors(bio), b->sectors_free),
+ queue_max_sectors(bdev_get_queue(c->bdev)));
+
+ k = &s->keylist[s->nkeylist++];
+ close_open_bucket(b, k, split);
+
+ ret = "bio_split_front error";
+ if (!(n = bio_split_front(bio, split, NULL)))
+ goto err;
+
+ pr_debug("adding to cache key %llu -> offset %llu len %u",
+ KEY_OFFSET(k), PTR_OFFSET(k), PTR_SIZE(k));
+
+ n->bi_sector = PTR_OFFSET(k);
+ n->bi_bdev = c->bdev;
+ submit_bio(WRITE, n);
+ } while (n != bio);
+
+ ret = NULL;
+err:
+ return ret;
+}
+
+static void bio_complete(struct search_context *s)
+{
+ s->bio->bi_private = s->bi_private;
+ if (s->bi_end_io)
+ s->bi_end_io(s->bio, s->error);
+ return_f(s, NULL);
+}
+
+static void bio_complete_bounce(struct search_context *s)
+{
+ int i;
+ struct bio_vec *bv;
+ bio_for_each_segment(bv, s->bio, i)
+ __free_page(bv->bv_page);
+ bio_put(s->bio);
+ return_f(s, NULL);
+}
+
+static void cache_miss(struct search_context *s)
+{
+ BUG_ON(s->error);
+ if (bio_insert(s->q, s->cache_bio, s))
+ bio_endio(s->cache_bio, -EIO);
+}
+
+static void cache_miss_bounce(struct search_context *s)
+{
+ int i;
+ struct bio_vec *bv;
+
+ bio_for_each_segment(bv, s->cache_bio, i)
+ if (s->error)
+ __free_page(bv->bv_page);
+ else {
+ void *dst = kmap(bv->bv_page);
+ void *src = kmap(s->bio->bi_io_vec[i].bv_page);
+ memcpy(dst, src, PAGE_SIZE);
+ kunmap(dst);
+ kunmap(src);
+ }
+
+ s->bio->bi_private = s->bi_private;
+ s->bi_end_io(s->bio, s->error);
+ s->bi_end_io = NULL;
+
+ if (s->error ||
+ !(s->bio = bio_kmalloc(GFP_NOIO, s->cache_bio->bi_max_vecs))) {
+ bio_put(s->cache_bio);
+ return_f(s, NULL);
+ }
+
+ __bio_clone(s->bio, s->cache_bio);
+
+ if (bio_insert(s->q, s->cache_bio, s))
+ bio_endio(s->cache_bio, -EIO);
+}
+
+static void request_hook_endio(struct bio *bio, int error)
+{
+ struct search_context *s = bio->bi_private;
+ s->error = error;
+ BUG_ON(error);
+ put_search(s);
+}
+
+static void __request_hook_read(struct search_context *s)
+{
+ struct request_queue *q = s->q;
+ if (request_hook_read(s->q, s->bio, s))
+ if (q->make_request_fn(q, s->bio))
+ generic_make_request(s->bio);
+}
+
+static int request_hook_read(struct request_queue *q, struct bio *bio,
+ struct search_context *s)
+{
+ int ret = -1, i;
+ struct cache_device *c;
+
+ pr_debug("searching for %i sectors at %llu",
+ bio_sectors(bio), (uint64_t) bio->bi_sector);
+
+ list_for_each_entry(c, &cache_devices, list) {
+ int dev = lookup_dev(c, bio);
+ if (dev == UUIDS_PER_SB)
+ return_f(s, NULL, 1);
+
+ ret = max(ret, run_on_root(false, btree_search_recurse, dev, bio, &s));
+
+ if (ret == 1) {
+ cache_hit(c, bio);
+ return_f(s, NULL, 0);
+ } else {
+ cache_hit(c, bio->bi_next);
+ bio->bi_next = NULL;
+ }
+ }
+
+ if (!ret) {
+ s->q = q;
+ s->bio = bio;
+ return_f(s, __request_hook_read, 0);
+ }
+
+ pr_debug("cache miss for %llu, starting write",
+ (uint64_t) bio->bi_sector);
+ cache_misses++;
+
+ list_for_each_entry(c, &cache_devices, list)
+ rescale_heap(c, bio_sectors(bio));
+
+ if (IS_ERR(s = alloc_search(s)) ||
+ !(s->cache_bio = bio_kmalloc(GFP_NOIO, bio->bi_max_vecs)))
+ return_f(s, NULL, 1);
+
+ s->parent = bio_complete_bounce;
+ s->end_fn = cache_miss_bounce;
+ s->q = get_current();
+ s->bio = bio;
+ s->bi_end_io = bio->bi_end_io;
+ s->bi_private = bio->bi_private;
+
+ bio->bi_end_io = request_hook_endio;
+ bio->bi_private = s;
+
+ __bio_clone(s->cache_bio, bio);
+ for (i = bio->bi_idx; i < bio->bi_vcnt; i++)
+ if (!(s->cache_bio->bi_io_vec[i].bv_page =
+ alloc_page(GFP_NOIO)))
+ break;
+
+ if (i != bio->bi_vcnt) {
+ while (i > bio->bi_idx)
+ __free_page(s->cache_bio->bi_io_vec[i].bv_page);
+
+ memcpy(s->cache_bio->bi_io_vec, bio->bi_io_vec,
+ bio->bi_max_vecs * sizeof(struct bio_vec));
+
+ s->parent = bio_complete;
+ s->end_fn = cache_miss;
+ }
+ return 1;
+}
+
+static int request_hook_write(struct request_queue *q, struct bio *bio)
+{
+ struct search_context *s;
+ struct bio *n = NULL;
+ const char *err = "couldn't allocate memory";
+
+ if (IS_ERR(s = alloc_search(NULL)))
+ goto err;
+
+ s->bio = bio;
+ s->bi_end_io = bio->bi_end_io;
+ s->bi_private = bio->bi_private;
+ s->parent = bio_complete;
+
+ if (!(n = bio_kmalloc(GFP_NOIO, bio->bi_max_vecs)))
+ goto err;
+
+ bio->bi_end_io = request_hook_endio;
+ bio->bi_private = s;
+
+ __bio_clone(n, bio);
+ atomic_inc(&s->remaining);
+
+ if ((err = bio_insert(get_current(), n, s)))
+ goto err;
+
+ return 1;
+err:
+ printk(KERN_WARNING "bcache: write error: %s\n", err);
+ /* XXX: write a null key or invalidate cache or fail write */
+
+ if (s)
+ put_search(s);
+
+ if (n)
+ bio_endio(n, 0);
+ return 1;
+}
+
+static void unplug_hook(struct request_queue *q)
+{
+ struct cache_device *c;
+ list_for_each_entry(c, &cache_devices, list)
+ blk_unplug(bdev_get_queue(c->bdev));
+ q->cache_unplug_fn(q);
+}
+
+static int request_hook(struct request_queue *q, struct bio *bio)
+{
+ if (!bio_has_data(bio) ||
+ list_empty(&cache_devices))
+ return 1;
+
+ if (q->unplug_fn != unplug_hook) {
+ q->cache_unplug_fn = q->unplug_fn;
+ q->unplug_fn = unplug_hook;
+ }
+
+ if (bio_rw_flagged(bio, BIO_RW))
+ return request_hook_write(q, bio);
+ else
+ return request_hook_read(q, bio, NULL);
+}
+
+#define write_attribute(n) \
+ static struct attribute sysfs_##n = { .name = #n, .mode = S_IWUSR }
+#define read_attribute(n) \
+ static struct attribute sysfs_##n = { .name = #n, .mode = S_IRUSR }
+#define rw_attribute(n) \
+ static struct attribute sysfs_##n = \
+ { .name = #n, .mode = S_IWUSR|S_IRUSR }
+
+#define sysfs_print(file, ...) \
+ if (attr == &sysfs_ ## file) \
+ return snprintf(buffer, PAGE_SIZE, __VA_ARGS__)
+
+#define sysfs_atoi(file, var) \
+ if (attr == &sysfs_ ## file) { \
+ unsigned long _v, _r = strict_strtoul(buffer, 10, &_v); \
+ if (_r) \
+ return _r; \
+ var = _v; \
+ }
+
+write_attribute(register_cache);
+write_attribute(register_dev);
+write_attribute(unregister);
+write_attribute(clear_stats);
+
+read_attribute(bucket_size);
+read_attribute(nbuckets);
+read_attribute(cache_hits);
+read_attribute(cache_hit_ratio);
+read_attribute(cache_misses);
+read_attribute(tree_depth);
+read_attribute(min_priority);
+read_attribute(pinned_buckets);
+read_attribute(lru_end);
+read_attribute(heap_size);
+read_attribute(kb_written);
+
+rw_attribute(cache_priority_initial);
+rw_attribute(cache_priority_hit);
+rw_attribute(cache_priority_seek);
+rw_attribute(cache_priority_rescale);
+
+static struct dentry *debug;
+
+static int dump_tree(struct cached_bucket *b, struct seq_file *f, char *space,
+ uint64_t *prev, uint64_t *sectors, struct search_context *s)
+{
+ int j, nread;
+ struct btree_key **i;
+ char buf[30];
+ uint64_t biggest = 0;
+ struct cached_bucket *r;
+
+ seq_printf(f, "%spage key: dev key -> offset len gen bucket\n", space + 3);
+
+ for_each_sorted_set(i, b) {
+ uint64_t last = *prev;
+ for (j = 1; j <= keys(i); j++) {
+ if (last > node(i, j)->key)
+ seq_printf(f, "Key skipped backwards\n");
+
+ if (!b->level &&
+ j > 1 &&
+ last != node(i, j)->key - PTR_SIZE(node(i, j)))
+ seq_printf(f, "<hole>\n");
+ else if (b->level &&
+ !ptr_bad(b, node(i, j))) {
+ r = get_bucket(b, node(i, j), false, &s);
+ if (!IS_ERR_OR_NULL(r))
+ dump_tree(r, f, space - 4, &last, sectors, s);
+ }
+
+ ptr_status(b, node(i, j), buf);
+ seq_printf(f,
+ "%s%i %4i: %3i %10llu -> %9lli %4i %3i %6li %s\n",
+ space,
+ index(i, b), j,
+ KEY_DEV(node(i, j)), KEY_OFFSET(node(i, j)),
+ PTR_OFFSET(node(i, j)),
+ PTR_SIZE(node(i, j)),
+ PTR_GEN(node(i, j)),
+ sector_to_bucket(b->c, PTR_OFFSET(node(i, j))),
+ buf);
+
+ if (!b->level || !buf[0]) {
+ last = node(i, j)->key;
+ biggest = max(biggest, last);
+ }
+
+ if (!b->level && !buf[0])
+ *sectors += PTR_SIZE(node(i, j));
+ }
+ }
+ *prev = biggest;
+
+ label(again, BUG());
+ rw_unlock(false, b);
+ return 0;
+}
+
+static int debug_seq_show(struct seq_file *f, void *data)
+{
+ char space[31];
+ uint64_t last = 0, sectors = 0;
+ struct cache_device *c = f->private;
+ struct search_context s;
+ memset(&s, 0, sizeof(s));
+ s.flags |= SEARCH_BLOCK;
+
+ memset(space, ' ', 30);
+ space[30] = '\0';
+
+ run_on_root(false, dump_tree, f, &space[26], &last, §ors, &s);
+
+ seq_printf(f,
+ "root: (null) -> bucket %6li\n"
+ "%llu kb found\n",
+ sector_to_bucket(c, c->root->offset), sectors / 2);
+
+ return 0;
+}
+
+static int debug_seq_open(struct inode *inode, struct file *file)
+{
+ return single_open(file, debug_seq_show, inode->i_private);
+}
+
+static void load_priorites_endio(struct bio *bio, int error)
+{
+ int i;
+ for (i = 0; i < bio->bi_vcnt; i++)
+ put_page(bio->bi_io_vec[i].bv_page);
+
+ if (error)
+ printk(KERN_ERR "bcache: Error reading priorities");
+ wake_up(&pending);
+ bio_put(bio);
+}
+
+static void load_priorities(struct cache_device *c, bool zero)
+{
+ long i = 0, used = 0;
+ struct bio *bio = c->priority_bio, *split;
+
+ bio_get(bio);
+ bio->bi_sector = PRIO_SECTOR;
+ bio->bi_bdev = c->bdev;
+ bio->bi_vcnt = pages(c, struct bucket_disk);
+ bio->bi_size = pages(c, struct bucket_disk) * PAGE_SIZE;
+
+ bio->bi_end_io = load_priorites_endio;
+ bio->bi_private = c;
+
+ for (i = 0; i < pages(c, struct bucket_disk); i++) {
+ bio->bi_io_vec[i].bv_page =
+ vmalloc_to_page((void *) c->disk_buckets
+ + PAGE_SIZE * i);
+ bio->bi_io_vec[i].bv_len = PAGE_SIZE;
+ bio->bi_io_vec[i].bv_offset = 0;
+ get_page(bio->bi_io_vec[i].bv_page);
+ }
+
+ pr_debug("max vecs %i\n", bio_get_nr_vecs(c->bdev));
+ mdelay(10);
+
+ do {
+ if (!(split = bio_split_front(bio, bio_get_nr_vecs(c->bdev)
+ * PAGE_SECTORS, NULL)))
+ return;
+ submit_bio(READ, split);
+ } while (split != bio);
+
+ wait_event(pending, atomic_read(&bio->bi_remaining) == 0);
+
+ for (i = 0; i < c->sb.nbuckets; i++) {
+ atomic_set(&c->buckets[i].pin, 0);
+ c->buckets[i].heap = -1;
+
+ c->buckets[i].priority =
+ le16_to_cpu(c->disk_buckets[i].priority);
+ c->buckets[i].gen = c->disk_buckets[i].gen;
+
+ if (zero)
+ c->buckets[i].priority = c->buckets[i].gen = 0;
+
+ c->buckets[i].last_gc = c->buckets[i].gen;
+
+ if (c->buckets[i].priority != (uint16_t) ~0 &&
+ c->buckets[i].priority)
+ used++;
+
+ if (c->buckets[i].priority != (uint16_t) ~0)
+ if (c->buckets[i].priority != 0 ||
+ !fifo_push(&c->free, i))
+ heap_insert(c, i);
+ }
+ pr_debug("Cache loaded, %li buckets in use", used);
+}
+
+static struct bio *save_priorities(struct cache_device *c)
+{
+ long i = 0, used = 0;
+ struct bio *bio = c->priority_bio;
+
+ if (!bio_reinit(bio))
+ return NULL;
+
+ bio->bi_sector = PRIO_SECTOR;
+ bio->bi_bdev = c->bdev;
+ bio->bi_vcnt = pages(c, struct bucket_disk);
+ bio->bi_size = pages(c, struct bucket_disk) * PAGE_SIZE;
+
+ bio->bi_end_io = write_endio;
+ bio->bi_private = c;
+
+ for (i = 0; i < c->sb.nbuckets; i++) {
+ c->disk_buckets[i].priority =
+ cpu_to_le16(c->buckets[i].priority);
+ c->disk_buckets[i].gen = c->buckets[i].gen;
+
+ if (c->buckets[i].priority != (uint16_t) ~0 &&
+ c->buckets[i].priority)
+ used++;
+ }
+
+ for (i = 0; i < pages(c, struct bucket_disk); i++) {
+ bio->bi_io_vec[i].bv_page =
+ vmalloc_to_page((void *) c->disk_buckets
+ + PAGE_SIZE * i);
+ bio->bi_io_vec[i].bv_len = PAGE_SIZE;
+ bio->bi_io_vec[i].bv_offset = 0;
+ get_page(bio->bi_io_vec[i].bv_page);
+ }
+
+ pr_debug("Cache written, %li buckets in use", used);
+ return bio;
+}
+
+static void register_dev_on_cache(struct cache_device *c, int d)
+{
+ int i;
+
+ for (i = 0; i < UUIDS_PER_SB; i++) {
+ if (is_zero(&c->uuids->b_data[i*16], 16)) {
+ pr_debug("inserted new uuid at %i", i);
+ memcpy(c->uuids->b_data + i*16, &uuids[d*16], 16);
+ set_buffer_dirty(c->uuids);
+ sync_dirty_buffer(c->uuids);
+ break;
+ }
+
+ if (!memcmp(&c->uuids->b_data[i*16], &uuids[d*16], 16)) {
+ /* Need to check if device was already opened
+ * read/write and invalidate previous data if it was.
+ */
+ pr_debug("looked up uuid at %i", i);
+ break;
+ }
+ }
+
+ if (i == UUIDS_PER_SB) {
+ printk(KERN_DEBUG "Aiee! No room for the uuid");
+ return;
+ }
+
+ c->devices[i] = d;
+}
+
+/*static ssize_t store_dev(struct kobject *kobj, struct attribute *attr,
+ const char *buffer, size_t size)
+{
+ if (attr == &sysfs_unregister) {
+ }
+ return size;
+}
+
+static void unregister_dev(struct kobject *k)
+{
+
+}*/
+
+static void register_dev(const char *buffer, size_t size)
+{
+ int i;
+ const char *err = NULL;
+ char *path = NULL;
+ unsigned char uuid[16];
+ struct block_device *bdev = NULL;
+ struct cached_dev *d = NULL;
+ struct cache_device *c;
+
+ /*static struct attribute *files[] = {
+ &sysfs_unregister,
+ NULL
+ };
+ static const struct sysfs_ops ops = {
+ .show = NULL,
+ .store = store_dev
+ };
+ static struct kobj_type dev_obj = {
+ .release = unregister_dev,
+ .sysfs_ops = &ops,
+ .default_attrs = files
+ };*/
+
+ if (!try_module_get(THIS_MODULE))
+ return;
+
+ err = "Bad uuid";
+ i = parse_uuid(buffer, &uuid[0]);
+ if (i < 4)
+ goto err;
+
+ err = "Insufficient memory";
+ if (!(path = kmalloc(size + 1 - i, GFP_KERNEL)) ||
+ !(d = kzalloc(sizeof(*d), GFP_KERNEL)))
+ goto err;
+
+ strcpy(path, skip_spaces(buffer + i));
+ bdev = lookup_bdev(strim(path));
+
+ err = "Failed to open device";
+ if (IS_ERR(bdev))
+ goto err;
+
+ err = "Aready registered";
+ for (i = 0;
+ i < UUIDS_PER_SB && !is_zero(&uuids[i*16], 16);
+ i++)
+ if (!memcmp(&uuids[i*16], uuid, 16))
+ goto err;
+
+ err = "Max devices already open";
+ if (i == UUIDS_PER_SB)
+ goto err;
+
+#if 0
+ blkdev_get(bdev, FMODE_READ|FMODE_WRITE))
+ bdevname(bdev, b);
+ err = "Error creating kobject";
+ if (!kobject_get(bcache_kobj) ||
+ kobject_init_and_add(&d->kobj, &dev_obj,
+ bcache_kobj,
+ "%s", b))
+ goto err;
+#endif
+
+ memcpy(&uuids[i*16], uuid, 16);
+ bdev->bd_cache_identifier = i;
+ /*devices[i] = bdev->bd_disk;*/
+
+ list_for_each_entry(c, &cache_devices, list)
+ register_dev_on_cache(c, i);
+
+ bdev->bd_cache_fn = request_hook;
+ printk(KERN_DEBUG "bcache: Caching %s index %i", path, i);
+
+ if (0) {
+err: printk(KERN_DEBUG "bcache: error opening %s: %s", path, err);
+ if (!IS_ERR_OR_NULL(bdev))
+ bdput(bdev);
+ kfree(d);
+ }
+ kfree(path);
+}
+
+static void unregister_cache_kobj(struct work_struct *w)
+{
+ struct cache_device *c = container_of(w, struct cache_device, work);
+ list_del(&c->list);
+ INIT_LIST_HEAD(&c->list);
+ kobject_put(&c->kobj);
+}
+
+static ssize_t store_cache(struct kobject *kobj, struct attribute *attr,
+ const char *buffer, size_t size)
+{
+ struct cache_device *c = container_of(kobj, struct cache_device, kobj);
+ if (attr == &sysfs_unregister) {
+ INIT_WORK(&c->work, unregister_cache_kobj);
+ schedule_work(&c->work);
+ }
+ return size;
+}
+
+static ssize_t show_cache(struct kobject *kobj, struct attribute *attr,
+ char *buffer)
+{
+ struct cache_device *c = container_of(kobj, struct cache_device, kobj);
+ struct cached_bucket *b;
+
+ sysfs_print(bucket_size, "%i\n", c->sb.bucket_size << 9);
+ sysfs_print(nbuckets, "%lli\n", c->sb.nbuckets);
+ sysfs_print(cache_hits, "%lu\n", c->cache_hits);
+ sysfs_print(tree_depth, "%u\n", c->sb.btree_level);
+ sysfs_print(min_priority, "%u\n", c->heap[0] ? c->heap[0]->priority : 0);
+ sysfs_print(heap_size, "%zu\n", c->heap_size);
+ sysfs_print(kb_written, "%lu\n", c->sectors_written / 2);
+ if (attr == &sysfs_pinned_buckets) {
+ struct list_head *l;
+ int i = 0;
+ spin_lock(&c->bucket_lock);
+ list_for_each(l, &c->lru)
+ i++;
+ spin_unlock(&c->bucket_lock);
+ return snprintf(buffer, PAGE_SIZE, "%i\n", i);
+ }
+ if (attr == &sysfs_lru_end) {
+ b = list_entry(c->lru.prev, struct cached_bucket, lru);
+ return snprintf(buffer, PAGE_SIZE, "%li\n",
+ sector_to_bucket(c, b->offset));
+ }
+ return 0;
+}
+
+static const char *read_super(struct cache_device *c)
+{
+ const char *err;
+ struct cache_sb *s;
+ struct buffer_head *bh;
+
+ if (!(bh = __bread(c->bdev, 1, 4096)))
+ return "IO error";
+
+ err = "Not a bcache superblock";
+ s = (struct cache_sb *) bh->b_data;
+ if (memcmp(s->magic, bcache_magic, 16))
+ goto err;
+
+ c->sb.version = le32_to_cpu(s->version);
+ c->sb.block_size = le16_to_cpu(s->block_size);
+ c->sb.bucket_size = le16_to_cpu(s->bucket_size);
+ c->sb.journal_start = le32_to_cpu(s->journal_start);
+ c->sb.first_bucket = le32_to_cpu(s->first_bucket);
+ c->sb.nbuckets = le64_to_cpu(s->nbuckets);
+ c->sb.btree_root = le64_to_cpu(s->btree_root);
+ c->sb.btree_level = le16_to_cpu(s->btree_level);
+
+ err = "Unsupported superblock version";
+ if (c->sb.version > CACHE_CLEAN)
+ goto err;
+
+ err = "Bad block/bucket size";
+ if (!c->sb.block_size ||
+ c->sb.bucket_size & (PAGE_SIZE / 512 - 1) ||
+ c->sb.bucket_size < c->sb.block_size)
+ goto err;
+
+ err = "Too many buckets";
+ if (c->sb.nbuckets > LONG_MAX)
+ goto err;
+
+ err = "Invalid superblock: journal overwrites bucket priorites";
+ if (c->sb.journal_start * c->sb.bucket_size <
+ 24 + ((c->sb.nbuckets * sizeof(struct bucket_disk)) >> 9))
+ goto err;
+
+ err = "Invalid superblock: first bucket comes before journal start";
+ if (c->sb.first_bucket < c->sb.journal_start)
+ goto err;
+
+ err = "Invalid superblock: device too small";
+ if (get_capacity(c->bdev->bd_disk) <
+ bucket_to_sector(c, c->sb.nbuckets))
+ goto err;
+
+ err = "Bucket size must be multiple of page size";
+ if (!pages_per_btree ||
+ c->sb.bucket_size & ((PAGE_SIZE >> 9) - 1))
+ goto err;
+
+ if (c->sb.btree_root < bucket_to_sector(c, 0) ||
+ c->sb.btree_root >= bucket_to_sector(c, c->sb.nbuckets))
+ c->sb.version &= ~CACHE_CLEAN;
+
+ err = NULL;
+
+ get_page(bh->b_page);
+ c->sb_page = bh->b_page;
+err:
+ put_bh(bh);
+ return err;
+}
+
+static struct bio *write_super(struct cache_device *c)
+{
+ struct bio *bio = c->sb_bio;
+ struct cache_sb *s = page_address(bio->bi_io_vec[0].bv_page);
+
+ if (!bio_reinit(bio))
+ return NULL;
+
+ get_page(bio->bi_io_vec[0].bv_page);
+
+ BUG_ON(list_empty(&c->list) != (c->sb.version & CACHE_CLEAN));
+ pr_debug("ver %i, root %llu, level %i",
+ c->sb.version, c->sb.btree_root, c->sb.btree_level);
+
+ bio->bi_sector = SB_SECTOR;
+ bio->bi_bdev = c->bdev;
+ bio->bi_vcnt = 1;
+ bio->bi_size = 4096;
+
+ bio->bi_end_io = write_endio;
+ bio->bi_private = c;
+
+ s->version = cpu_to_le32(c->sb.version);
+ s->block_size = cpu_to_le16(c->sb.block_size);
+ s->bucket_size = cpu_to_le16(c->sb.bucket_size);
+ s->journal_start = cpu_to_le32(c->sb.journal_start);
+ s->first_bucket = cpu_to_le32(c->sb.first_bucket);
+ s->nbuckets = cpu_to_le64(c->sb.nbuckets);
+ s->btree_root = cpu_to_le64(c->sb.btree_root);
+ s->btree_level = cpu_to_le16(c->sb.btree_level);
+ return bio;
+}
+
+static void free_cache(struct cache_device *c)
+{
+ struct cached_bucket *b;
+
+ while (!list_empty(&c->lru)) {
+ b = list_first_entry(&c->lru, struct cached_bucket, lru);
+ list_del(&b->lru);
+ free_bucket_contents(b);
+ kfree(b);
+ }
+
+ if (!IS_ERR_OR_NULL(c->debug))
+ debugfs_remove(c->debug);
+
+ if (c->kobj.state_initialized) {
+ kobject_put(bcache_kobj);
+ kobject_put(&c->kobj);
+ }
+
+ free_fifo(&c->free);
+ if (c->sb_bio)
+ bio_put(c->sb_bio);
+ if (c->priority_bio)
+ bio_put(c->priority_bio);
+
+ vfree(c->garbage);
+ vfree(c->disk_buckets);
+ vfree(c->buckets);
+ vfree(c->heap);
+ if (c->uuids)
+ put_bh(c->uuids);
+ if (c->sb_page)
+ put_page(c->sb_page);
+ if (!IS_ERR_OR_NULL(c->bdev))
+ close_bdev_exclusive(c->bdev, FMODE_READ|FMODE_WRITE);
+
+ module_put(c->owner);
+ kfree(c);
+}
+
+static void register_cache(const char *buffer, size_t size)
+{
+ int i;
+ const char *err = NULL;
+ char *path = NULL, b[BDEVNAME_SIZE];
+ struct cache_device *c = NULL;
+ struct search_context s, *sp = &s;
+
+ static struct attribute *files[] = {
+ &sysfs_unregister,
+ &sysfs_bucket_size,
+ &sysfs_nbuckets,
+ &sysfs_cache_hits,
+ &sysfs_tree_depth,
+ &sysfs_min_priority,
+ &sysfs_pinned_buckets,
+ &sysfs_lru_end,
+ &sysfs_heap_size,
+ &sysfs_kb_written,
+ NULL
+ };
+ static const struct sysfs_ops ops = {
+ .show = show_cache,
+ .store = store_cache
+ };
+ static struct kobj_type cache_obj = {
+ .release = unregister_cache,
+ .sysfs_ops = &ops,
+ .default_attrs = files
+ };
+
+ if (!try_module_get(THIS_MODULE))
+ return;
+
+ err = "Insufficient memory";
+ if (!(path = kmalloc(size + 1, GFP_KERNEL)) ||
+ !(c = kzalloc(sizeof(*c), GFP_KERNEL)))
+ goto err;
+
+ c->owner = THIS_MODULE;
+ INIT_LIST_HEAD(&c->lru);
+
+ strcpy(path, skip_spaces(buffer));
+
+ err = "Failed to open cache device";
+ c->bdev = open_bdev_exclusive(strim(path), FMODE_READ|FMODE_WRITE, c);
+ if (IS_ERR(c->bdev))
+ goto err;
+
+ set_blocksize(c->bdev, 4096);
+
+ if ((err = read_super(c)))
+ goto err;
+
+ err = "IO error reading UUIDs";
+ if (!(c->uuids = __bread(c->bdev, 2, PAGE_SIZE)))
+ goto err;
+
+ err = "Not enough buckets";
+ if (c->sb.nbuckets >> 7 <= 1)
+ goto err;
+
+ err = "Insufficient memory";
+ if (!(c->heap = vmalloc(c->sb.nbuckets * sizeof(struct bucket *))) ||
+ !(c->buckets = vmalloc(c->sb.nbuckets * sizeof(struct bucket))) ||
+ !(c->disk_buckets = vmalloc(c->sb.nbuckets * sizeof(struct bucket_disk))) ||
+ !(c->garbage = vmalloc(c->sb.nbuckets * sizeof(struct bucket_gc))) ||
+ !(c->sb_bio = bio_kmalloc(GFP_KERNEL, 1)) ||
+ !(c->priority_bio = bio_kmalloc(GFP_KERNEL, pages(c, struct bucket_disk))) ||
+ !init_fifo(&c->free, c->sb.nbuckets >> 7, GFP_KERNEL))
+ goto err;
+
+ atomic_set(&c->sb_bio->bi_remaining, 0);
+ c->sb_bio->bi_io_vec[0].bv_page = c->sb_page;
+ c->sb_bio->bi_io_vec[0].bv_len = 4096;
+ c->sb_bio->bi_io_vec[0].bv_offset = 0;
+
+ memset(c->heap, 0, c->sb.nbuckets * sizeof(struct bucket *));
+ memset(c->buckets, 0, c->sb.nbuckets * sizeof(struct bucket));
+
+ spin_lock_init(&c->sb_lock);
+ spin_lock_init(&c->bucket_lock);
+ init_MUTEX(&c->gc_lock);
+
+ c->rescale = rescale;
+ c->btree_buckets_cached = 8;
+
+ load_priorities(c, !(c->sb.version & CACHE_CLEAN));
+
+ memset(&s, 0, sizeof(s));
+ if (c->sb.version & CACHE_CLEAN)
+ c->root = __get_bucket(c, c->sb.btree_root,
+ c->sb.btree_level, true, &sp);
+ else
+ printk(KERN_DEBUG "bcache: Cache device %s was dirty, invalidating existing data", path);
+
+ c->sb.version &= ~CACHE_CLEAN;
+ if (!c->root) {
+ if (!(c->root = btree_alloc(c, 0, NULL, 0, 0, false)))
+ goto err;
+
+ set_new_root(c->root);
+ } else
+ list_del_init(&c->root->lru);
+
+ rw_unlock(true, c->root);
+ BUG_ON(sector_to_priority(c, c->root->offset) != (uint16_t) ~0);
+
+#if 0
+ memset(c->garbage, 0, c->sb.nbuckets * sizeof(struct bucket_gc));
+ for (i = 0; i < c->sb.nbuckets; i++)
+ c->garbage[i].gen = c->buckets[i].gen;
+
+ down(&c->gc_lock);
+ do_btree_gc(&c->work);
+#endif
+
+ for (i = 0; i < UUIDS_PER_SB; i++)
+ c->devices[i] = ~0;
+
+ for (i = 0; i < UUIDS_PER_SB && !is_zero(&uuids[i*16], 16); i++)
+ register_dev_on_cache(c, i);
+
+ err = "Error creating kobject";
+ bdevname(c->bdev, b);
+ if (!kobject_get(bcache_kobj) ||
+ kobject_init_and_add(&c->kobj, &cache_obj,
+ bcache_kobj,
+ "%s", b))
+ goto err;
+
+ if (!IS_ERR_OR_NULL(debug)) {
+ static const struct file_operations treeops = {
+ .owner = THIS_MODULE,
+ .open = debug_seq_open,
+ .read = seq_read,
+ .release = single_release };
+
+ c->debug = debugfs_create_file(b, 0400, debug, c, &treeops);
+ }
+
+ list_add(&c->list, &cache_devices);
+
+ printk(KERN_DEBUG "bcache: Loaded cache device %s", path);
+ pr_debug("btree root at %llu", (uint64_t) c->root->offset);
+
+ if (0) {
+err: printk(KERN_DEBUG "bcache: error opening %s: %s", path, err);
+ if (c) {
+ if (c->bdev == ERR_PTR(-EBUSY))
+ err = "Device busy";
+ if (c->root)
+ list_add(&c->root->lru, &c->lru);
+ free_cache(c);
+ }
+ }
+ kfree(path);
+}
+
+static void unregister_cache(struct kobject *k)
+{
+ struct cache_device *c = container_of(k, struct cache_device, kobj);
+ struct cached_bucket *b;
+
+ /* should write out current key
+ */
+
+ list_add(&c->root->lru, &c->lru);
+ list_for_each_entry(b, &c->lru, lru)
+ __btree_write(b, 0, atomic_read(&b->nread), b->offset);
+
+ c->sb.version |= CACHE_CLEAN;
+
+ submit_bio_list(WRITE, save_priorities(c));
+ submit_bio_list(WRITE, write_super(c));
+ free_cache(c);
+}
+
+static ssize_t show(struct kobject *kobj, struct attribute *attr, char *buffer)
+{
+ sysfs_print(cache_hits, "%lu\n", cache_hits);
+ sysfs_print(cache_hit_ratio, "%lu%%\n",
+ cache_hits + cache_misses ?
+ cache_hits * 100 / (cache_hits + cache_misses) : 0);
+ sysfs_print(cache_misses, "%lu\n", cache_misses);
+ sysfs_print(cache_priority_initial, "%i\n", initial_priority);
+ sysfs_print(cache_priority_hit, "%i\n", cache_hit_priority);
+ sysfs_print(cache_priority_seek, "%i\n", cache_hit_seek);
+ sysfs_print(cache_priority_rescale, "%li\n", rescale);
+ return 0;
+}
+
+static ssize_t store(struct kobject *kobj, struct attribute *attr,
+ const char *buffer, size_t size)
+{
+ if (attr == &sysfs_register_cache)
+ register_cache(buffer, size);
+ if (attr == &sysfs_register_dev)
+ register_dev(buffer, size);
+ sysfs_atoi(cache_priority_initial, initial_priority);
+ sysfs_atoi(cache_priority_hit, cache_hit_priority);
+ sysfs_atoi(cache_priority_seek, cache_hit_seek);
+ sysfs_atoi(cache_priority_rescale, rescale);
+ if (attr == &sysfs_clear_stats) {
+ struct cache_device *c;
+ list_for_each_entry(c, &cache_devices, list)
+ c->cache_hits = 0;
+
+ cache_hits = cache_misses = 0;
+ }
+
+ return size;
+}
+
+static int __init bcache_init(void)
+{
+ static const struct sysfs_ops ops = { .show = show, .store = store };
+ static const struct attribute *files[] = { &sysfs_register_cache,
+ &sysfs_register_dev,
+ &sysfs_cache_hits,
+ &sysfs_cache_hit_ratio,
+ &sysfs_cache_misses,
+ &sysfs_cache_priority_initial,
+ &sysfs_cache_priority_hit,
+ &sysfs_cache_priority_seek,
+ &sysfs_cache_priority_rescale,
+ &sysfs_clear_stats,
+ NULL};
+
+ printk(KERN_DEBUG "bcache loading");
+
+ delayed = create_workqueue("bcache");
+ if (!delayed)
+ return -ENOMEM;
+
+ debug = debugfs_create_dir("bcache", NULL);
+
+ bcache_kobj = kobject_create_and_add("bcache", kernel_kobj);
+ if (!bcache_kobj)
+ return -ENOMEM;
+
+ bcache_kobj->ktype->sysfs_ops = &ops;
+ return sysfs_create_files(bcache_kobj, files);
+}
+
+static void bcache_exit(void)
+{
+ struct cache_device *c;
+
+ if (!IS_ERR_OR_NULL(debug))
+ debugfs_remove_recursive(debug);
+
+ sysfs_remove_file(bcache_kobj, &sysfs_register_cache);
+ sysfs_remove_file(bcache_kobj, &sysfs_register_dev);
+
+ /*for (i = 0; i < UUIDS_PER_SB; i++)
+ if (devices[i] && devices[i])
+ devices[i]->bd_cache_fn = NULL;*/
+
+ list_for_each_entry(c, &cache_devices, list)
+ kobject_put(&c->kobj);
+}
+
+module_init(bcache_init);
+module_exit(bcache_exit);
--
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