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-rw-r--r--drivers/md/bcache/extents.c630
1 files changed, 630 insertions, 0 deletions
diff --git a/drivers/md/bcache/extents.c b/drivers/md/bcache/extents.c
new file mode 100644
index 000000000..f4658a1f3
--- /dev/null
+++ b/drivers/md/bcache/extents.c
@@ -0,0 +1,630 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2010 Kent Overstreet <kent.overstreet@gmail.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/admin-guide/bcache.rst.
+ */
+
+#include "bcache.h"
+#include "btree.h"
+#include "debug.h"
+#include "extents.h"
+#include "writeback.h"
+
+static void sort_key_next(struct btree_iter *iter,
+ struct btree_iter_set *i)
+{
+ i->k = bkey_next(i->k);
+
+ if (i->k == i->end)
+ *i = iter->data[--iter->used];
+}
+
+static bool bch_key_sort_cmp(struct btree_iter_set l,
+ struct btree_iter_set r)
+{
+ int64_t c = bkey_cmp(l.k, r.k);
+
+ return c ? c > 0 : l.k < r.k;
+}
+
+static bool __ptr_invalid(struct cache_set *c, const struct bkey *k)
+{
+ unsigned int i;
+
+ for (i = 0; i < KEY_PTRS(k); i++)
+ if (ptr_available(c, k, i)) {
+ struct cache *ca = PTR_CACHE(c, k, i);
+ size_t bucket = PTR_BUCKET_NR(c, k, i);
+ size_t r = bucket_remainder(c, PTR_OFFSET(k, i));
+
+ if (KEY_SIZE(k) + r > c->cache->sb.bucket_size ||
+ bucket < ca->sb.first_bucket ||
+ bucket >= ca->sb.nbuckets)
+ return true;
+ }
+
+ return false;
+}
+
+/* Common among btree and extent ptrs */
+
+static const char *bch_ptr_status(struct cache_set *c, const struct bkey *k)
+{
+ unsigned int i;
+
+ for (i = 0; i < KEY_PTRS(k); i++)
+ if (ptr_available(c, k, i)) {
+ struct cache *ca = PTR_CACHE(c, k, i);
+ size_t bucket = PTR_BUCKET_NR(c, k, i);
+ size_t r = bucket_remainder(c, PTR_OFFSET(k, i));
+
+ if (KEY_SIZE(k) + r > c->cache->sb.bucket_size)
+ return "bad, length too big";
+ if (bucket < ca->sb.first_bucket)
+ return "bad, short offset";
+ if (bucket >= ca->sb.nbuckets)
+ return "bad, offset past end of device";
+ if (ptr_stale(c, k, i))
+ return "stale";
+ }
+
+ if (!bkey_cmp(k, &ZERO_KEY))
+ return "bad, null key";
+ if (!KEY_PTRS(k))
+ return "bad, no pointers";
+ if (!KEY_SIZE(k))
+ return "zeroed key";
+ return "";
+}
+
+void bch_extent_to_text(char *buf, size_t size, const struct bkey *k)
+{
+ unsigned int i = 0;
+ char *out = buf, *end = buf + size;
+
+#define p(...) (out += scnprintf(out, end - out, __VA_ARGS__))
+
+ p("%llu:%llu len %llu -> [", KEY_INODE(k), KEY_START(k), KEY_SIZE(k));
+
+ for (i = 0; i < KEY_PTRS(k); i++) {
+ if (i)
+ p(", ");
+
+ if (PTR_DEV(k, i) == PTR_CHECK_DEV)
+ p("check dev");
+ else
+ p("%llu:%llu gen %llu", PTR_DEV(k, i),
+ PTR_OFFSET(k, i), PTR_GEN(k, i));
+ }
+
+ p("]");
+
+ if (KEY_DIRTY(k))
+ p(" dirty");
+ if (KEY_CSUM(k))
+ p(" cs%llu %llx", KEY_CSUM(k), k->ptr[1]);
+#undef p
+}
+
+static void bch_bkey_dump(struct btree_keys *keys, const struct bkey *k)
+{
+ struct btree *b = container_of(keys, struct btree, keys);
+ unsigned int j;
+ char buf[80];
+
+ bch_extent_to_text(buf, sizeof(buf), k);
+ pr_cont(" %s", buf);
+
+ for (j = 0; j < KEY_PTRS(k); j++) {
+ size_t n = PTR_BUCKET_NR(b->c, k, j);
+
+ pr_cont(" bucket %zu", n);
+ if (n >= b->c->cache->sb.first_bucket && n < b->c->cache->sb.nbuckets)
+ pr_cont(" prio %i",
+ PTR_BUCKET(b->c, k, j)->prio);
+ }
+
+ pr_cont(" %s\n", bch_ptr_status(b->c, k));
+}
+
+/* Btree ptrs */
+
+bool __bch_btree_ptr_invalid(struct cache_set *c, const struct bkey *k)
+{
+ char buf[80];
+
+ if (!KEY_PTRS(k) || !KEY_SIZE(k) || KEY_DIRTY(k))
+ goto bad;
+
+ if (__ptr_invalid(c, k))
+ goto bad;
+
+ return false;
+bad:
+ bch_extent_to_text(buf, sizeof(buf), k);
+ cache_bug(c, "spotted btree ptr %s: %s", buf, bch_ptr_status(c, k));
+ return true;
+}
+
+static bool bch_btree_ptr_invalid(struct btree_keys *bk, const struct bkey *k)
+{
+ struct btree *b = container_of(bk, struct btree, keys);
+
+ return __bch_btree_ptr_invalid(b->c, k);
+}
+
+static bool btree_ptr_bad_expensive(struct btree *b, const struct bkey *k)
+{
+ unsigned int i;
+ char buf[80];
+ struct bucket *g;
+
+ if (mutex_trylock(&b->c->bucket_lock)) {
+ for (i = 0; i < KEY_PTRS(k); i++)
+ if (ptr_available(b->c, k, i)) {
+ g = PTR_BUCKET(b->c, k, i);
+
+ if (KEY_DIRTY(k) ||
+ g->prio != BTREE_PRIO ||
+ (b->c->gc_mark_valid &&
+ GC_MARK(g) != GC_MARK_METADATA))
+ goto err;
+ }
+
+ mutex_unlock(&b->c->bucket_lock);
+ }
+
+ return false;
+err:
+ mutex_unlock(&b->c->bucket_lock);
+ bch_extent_to_text(buf, sizeof(buf), k);
+ btree_bug(b,
+"inconsistent btree pointer %s: bucket %zi pin %i prio %i gen %i last_gc %i mark %llu",
+ buf, PTR_BUCKET_NR(b->c, k, i), atomic_read(&g->pin),
+ g->prio, g->gen, g->last_gc, GC_MARK(g));
+ return true;
+}
+
+static bool bch_btree_ptr_bad(struct btree_keys *bk, const struct bkey *k)
+{
+ struct btree *b = container_of(bk, struct btree, keys);
+ unsigned int i;
+
+ if (!bkey_cmp(k, &ZERO_KEY) ||
+ !KEY_PTRS(k) ||
+ bch_ptr_invalid(bk, k))
+ return true;
+
+ for (i = 0; i < KEY_PTRS(k); i++)
+ if (!ptr_available(b->c, k, i) ||
+ ptr_stale(b->c, k, i))
+ return true;
+
+ if (expensive_debug_checks(b->c) &&
+ btree_ptr_bad_expensive(b, k))
+ return true;
+
+ return false;
+}
+
+static bool bch_btree_ptr_insert_fixup(struct btree_keys *bk,
+ struct bkey *insert,
+ struct btree_iter *iter,
+ struct bkey *replace_key)
+{
+ struct btree *b = container_of(bk, struct btree, keys);
+
+ if (!KEY_OFFSET(insert))
+ btree_current_write(b)->prio_blocked++;
+
+ return false;
+}
+
+const struct btree_keys_ops bch_btree_keys_ops = {
+ .sort_cmp = bch_key_sort_cmp,
+ .insert_fixup = bch_btree_ptr_insert_fixup,
+ .key_invalid = bch_btree_ptr_invalid,
+ .key_bad = bch_btree_ptr_bad,
+ .key_to_text = bch_extent_to_text,
+ .key_dump = bch_bkey_dump,
+};
+
+/* Extents */
+
+/*
+ * Returns true if l > r - unless l == r, in which case returns true if l is
+ * older than r.
+ *
+ * Necessary for btree_sort_fixup() - if there are multiple keys that compare
+ * equal in different sets, we have to process them newest to oldest.
+ */
+static bool bch_extent_sort_cmp(struct btree_iter_set l,
+ struct btree_iter_set r)
+{
+ int64_t c = bkey_cmp(&START_KEY(l.k), &START_KEY(r.k));
+
+ return c ? c > 0 : l.k < r.k;
+}
+
+static struct bkey *bch_extent_sort_fixup(struct btree_iter *iter,
+ struct bkey *tmp)
+{
+ while (iter->used > 1) {
+ struct btree_iter_set *top = iter->data, *i = top + 1;
+
+ if (iter->used > 2 &&
+ bch_extent_sort_cmp(i[0], i[1]))
+ i++;
+
+ if (bkey_cmp(top->k, &START_KEY(i->k)) <= 0)
+ break;
+
+ if (!KEY_SIZE(i->k)) {
+ sort_key_next(iter, i);
+ heap_sift(iter, i - top, bch_extent_sort_cmp);
+ continue;
+ }
+
+ if (top->k > i->k) {
+ if (bkey_cmp(top->k, i->k) >= 0)
+ sort_key_next(iter, i);
+ else
+ bch_cut_front(top->k, i->k);
+
+ heap_sift(iter, i - top, bch_extent_sort_cmp);
+ } else {
+ /* can't happen because of comparison func */
+ BUG_ON(!bkey_cmp(&START_KEY(top->k), &START_KEY(i->k)));
+
+ if (bkey_cmp(i->k, top->k) < 0) {
+ bkey_copy(tmp, top->k);
+
+ bch_cut_back(&START_KEY(i->k), tmp);
+ bch_cut_front(i->k, top->k);
+ heap_sift(iter, 0, bch_extent_sort_cmp);
+
+ return tmp;
+ } else {
+ bch_cut_back(&START_KEY(i->k), top->k);
+ }
+ }
+ }
+
+ return NULL;
+}
+
+static void bch_subtract_dirty(struct bkey *k,
+ struct cache_set *c,
+ uint64_t offset,
+ int sectors)
+{
+ if (KEY_DIRTY(k))
+ bcache_dev_sectors_dirty_add(c, KEY_INODE(k),
+ offset, -sectors);
+}
+
+static bool bch_extent_insert_fixup(struct btree_keys *b,
+ struct bkey *insert,
+ struct btree_iter *iter,
+ struct bkey *replace_key)
+{
+ struct cache_set *c = container_of(b, struct btree, keys)->c;
+
+ uint64_t old_offset;
+ unsigned int old_size, sectors_found = 0;
+
+ BUG_ON(!KEY_OFFSET(insert));
+ BUG_ON(!KEY_SIZE(insert));
+
+ while (1) {
+ struct bkey *k = bch_btree_iter_next(iter);
+
+ if (!k)
+ break;
+
+ if (bkey_cmp(&START_KEY(k), insert) >= 0) {
+ if (KEY_SIZE(k))
+ break;
+ else
+ continue;
+ }
+
+ if (bkey_cmp(k, &START_KEY(insert)) <= 0)
+ continue;
+
+ old_offset = KEY_START(k);
+ old_size = KEY_SIZE(k);
+
+ /*
+ * We might overlap with 0 size extents; we can't skip these
+ * because if they're in the set we're inserting to we have to
+ * adjust them so they don't overlap with the key we're
+ * inserting. But we don't want to check them for replace
+ * operations.
+ */
+
+ if (replace_key && KEY_SIZE(k)) {
+ /*
+ * k might have been split since we inserted/found the
+ * key we're replacing
+ */
+ unsigned int i;
+ uint64_t offset = KEY_START(k) -
+ KEY_START(replace_key);
+
+ /* But it must be a subset of the replace key */
+ if (KEY_START(k) < KEY_START(replace_key) ||
+ KEY_OFFSET(k) > KEY_OFFSET(replace_key))
+ goto check_failed;
+
+ /* We didn't find a key that we were supposed to */
+ if (KEY_START(k) > KEY_START(insert) + sectors_found)
+ goto check_failed;
+
+ if (!bch_bkey_equal_header(k, replace_key))
+ goto check_failed;
+
+ /* skip past gen */
+ offset <<= 8;
+
+ BUG_ON(!KEY_PTRS(replace_key));
+
+ for (i = 0; i < KEY_PTRS(replace_key); i++)
+ if (k->ptr[i] != replace_key->ptr[i] + offset)
+ goto check_failed;
+
+ sectors_found = KEY_OFFSET(k) - KEY_START(insert);
+ }
+
+ if (bkey_cmp(insert, k) < 0 &&
+ bkey_cmp(&START_KEY(insert), &START_KEY(k)) > 0) {
+ /*
+ * We overlapped in the middle of an existing key: that
+ * means we have to split the old key. But we have to do
+ * slightly different things depending on whether the
+ * old key has been written out yet.
+ */
+
+ struct bkey *top;
+
+ bch_subtract_dirty(k, c, KEY_START(insert),
+ KEY_SIZE(insert));
+
+ if (bkey_written(b, k)) {
+ /*
+ * We insert a new key to cover the top of the
+ * old key, and the old key is modified in place
+ * to represent the bottom split.
+ *
+ * It's completely arbitrary whether the new key
+ * is the top or the bottom, but it has to match
+ * up with what btree_sort_fixup() does - it
+ * doesn't check for this kind of overlap, it
+ * depends on us inserting a new key for the top
+ * here.
+ */
+ top = bch_bset_search(b, bset_tree_last(b),
+ insert);
+ bch_bset_insert(b, top, k);
+ } else {
+ BKEY_PADDED(key) temp;
+ bkey_copy(&temp.key, k);
+ bch_bset_insert(b, k, &temp.key);
+ top = bkey_next(k);
+ }
+
+ bch_cut_front(insert, top);
+ bch_cut_back(&START_KEY(insert), k);
+ bch_bset_fix_invalidated_key(b, k);
+ goto out;
+ }
+
+ if (bkey_cmp(insert, k) < 0) {
+ bch_cut_front(insert, k);
+ } else {
+ if (bkey_cmp(&START_KEY(insert), &START_KEY(k)) > 0)
+ old_offset = KEY_START(insert);
+
+ if (bkey_written(b, k) &&
+ bkey_cmp(&START_KEY(insert), &START_KEY(k)) <= 0) {
+ /*
+ * Completely overwrote, so we don't have to
+ * invalidate the binary search tree
+ */
+ bch_cut_front(k, k);
+ } else {
+ __bch_cut_back(&START_KEY(insert), k);
+ bch_bset_fix_invalidated_key(b, k);
+ }
+ }
+
+ bch_subtract_dirty(k, c, old_offset, old_size - KEY_SIZE(k));
+ }
+
+check_failed:
+ if (replace_key) {
+ if (!sectors_found) {
+ return true;
+ } else if (sectors_found < KEY_SIZE(insert)) {
+ SET_KEY_OFFSET(insert, KEY_OFFSET(insert) -
+ (KEY_SIZE(insert) - sectors_found));
+ SET_KEY_SIZE(insert, sectors_found);
+ }
+ }
+out:
+ if (KEY_DIRTY(insert))
+ bcache_dev_sectors_dirty_add(c, KEY_INODE(insert),
+ KEY_START(insert),
+ KEY_SIZE(insert));
+
+ return false;
+}
+
+bool __bch_extent_invalid(struct cache_set *c, const struct bkey *k)
+{
+ char buf[80];
+
+ if (!KEY_SIZE(k))
+ return true;
+
+ if (KEY_SIZE(k) > KEY_OFFSET(k))
+ goto bad;
+
+ if (__ptr_invalid(c, k))
+ goto bad;
+
+ return false;
+bad:
+ bch_extent_to_text(buf, sizeof(buf), k);
+ cache_bug(c, "spotted extent %s: %s", buf, bch_ptr_status(c, k));
+ return true;
+}
+
+static bool bch_extent_invalid(struct btree_keys *bk, const struct bkey *k)
+{
+ struct btree *b = container_of(bk, struct btree, keys);
+
+ return __bch_extent_invalid(b->c, k);
+}
+
+static bool bch_extent_bad_expensive(struct btree *b, const struct bkey *k,
+ unsigned int ptr)
+{
+ struct bucket *g = PTR_BUCKET(b->c, k, ptr);
+ char buf[80];
+
+ if (mutex_trylock(&b->c->bucket_lock)) {
+ if (b->c->gc_mark_valid &&
+ (!GC_MARK(g) ||
+ GC_MARK(g) == GC_MARK_METADATA ||
+ (GC_MARK(g) != GC_MARK_DIRTY && KEY_DIRTY(k))))
+ goto err;
+
+ if (g->prio == BTREE_PRIO)
+ goto err;
+
+ mutex_unlock(&b->c->bucket_lock);
+ }
+
+ return false;
+err:
+ mutex_unlock(&b->c->bucket_lock);
+ bch_extent_to_text(buf, sizeof(buf), k);
+ btree_bug(b,
+"inconsistent extent pointer %s:\nbucket %zu pin %i prio %i gen %i last_gc %i mark %llu",
+ buf, PTR_BUCKET_NR(b->c, k, ptr), atomic_read(&g->pin),
+ g->prio, g->gen, g->last_gc, GC_MARK(g));
+ return true;
+}
+
+static bool bch_extent_bad(struct btree_keys *bk, const struct bkey *k)
+{
+ struct btree *b = container_of(bk, struct btree, keys);
+ unsigned int i, stale;
+ char buf[80];
+
+ if (!KEY_PTRS(k) ||
+ bch_extent_invalid(bk, k))
+ return true;
+
+ for (i = 0; i < KEY_PTRS(k); i++)
+ if (!ptr_available(b->c, k, i))
+ return true;
+
+ for (i = 0; i < KEY_PTRS(k); i++) {
+ stale = ptr_stale(b->c, k, i);
+
+ if (stale && KEY_DIRTY(k)) {
+ bch_extent_to_text(buf, sizeof(buf), k);
+ pr_info("stale dirty pointer, stale %u, key: %s\n",
+ stale, buf);
+ }
+
+ btree_bug_on(stale > BUCKET_GC_GEN_MAX, b,
+ "key too stale: %i, need_gc %u",
+ stale, b->c->need_gc);
+
+ if (stale)
+ return true;
+
+ if (expensive_debug_checks(b->c) &&
+ bch_extent_bad_expensive(b, k, i))
+ return true;
+ }
+
+ return false;
+}
+
+static uint64_t merge_chksums(struct bkey *l, struct bkey *r)
+{
+ return (l->ptr[KEY_PTRS(l)] + r->ptr[KEY_PTRS(r)]) &
+ ~((uint64_t)1 << 63);
+}
+
+static bool bch_extent_merge(struct btree_keys *bk,
+ struct bkey *l,
+ struct bkey *r)
+{
+ struct btree *b = container_of(bk, struct btree, keys);
+ unsigned int i;
+
+ if (key_merging_disabled(b->c))
+ return false;
+
+ for (i = 0; i < KEY_PTRS(l); i++)
+ if (l->ptr[i] + MAKE_PTR(0, KEY_SIZE(l), 0) != r->ptr[i] ||
+ PTR_BUCKET_NR(b->c, l, i) != PTR_BUCKET_NR(b->c, r, i))
+ return false;
+
+ /* Keys with no pointers aren't restricted to one bucket and could
+ * overflow KEY_SIZE
+ */
+ if (KEY_SIZE(l) + KEY_SIZE(r) > USHRT_MAX) {
+ SET_KEY_OFFSET(l, KEY_OFFSET(l) + USHRT_MAX - KEY_SIZE(l));
+ SET_KEY_SIZE(l, USHRT_MAX);
+
+ bch_cut_front(l, r);
+ return false;
+ }
+
+ if (KEY_CSUM(l)) {
+ if (KEY_CSUM(r))
+ l->ptr[KEY_PTRS(l)] = merge_chksums(l, r);
+ else
+ SET_KEY_CSUM(l, 0);
+ }
+
+ SET_KEY_OFFSET(l, KEY_OFFSET(l) + KEY_SIZE(r));
+ SET_KEY_SIZE(l, KEY_SIZE(l) + KEY_SIZE(r));
+
+ return true;
+}
+
+const struct btree_keys_ops bch_extent_keys_ops = {
+ .sort_cmp = bch_extent_sort_cmp,
+ .sort_fixup = bch_extent_sort_fixup,
+ .insert_fixup = bch_extent_insert_fixup,
+ .key_invalid = bch_extent_invalid,
+ .key_bad = bch_extent_bad,
+ .key_merge = bch_extent_merge,
+ .key_to_text = bch_extent_to_text,
+ .key_dump = bch_bkey_dump,
+ .is_extents = true,
+};
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-27 18:05:12 +0000