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authorYunhong Jiang <yunhong.jiang@intel.com>2015-08-04 12:17:53 -0700
committerYunhong Jiang <yunhong.jiang@intel.com>2015-08-04 15:44:42 -0700
commit9ca8dbcc65cfc63d6f5ef3312a33184e1d726e00 (patch)
tree1c9cafbcd35f783a87880a10f85d1a060db1a563 /kernel/drivers/md/persistent-data
parent98260f3884f4a202f9ca5eabed40b1354c489b29 (diff)
Add the rt linux 4.1.3-rt3 as base
Import the rt linux 4.1.3-rt3 as OPNFV kvm base. It's from git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git linux-4.1.y-rt and the base is: commit 0917f823c59692d751951bf5ea699a2d1e2f26a2 Author: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Date: Sat Jul 25 12:13:34 2015 +0200 Prepare v4.1.3-rt3 Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> We lose all the git history this way and it's not good. We should apply another opnfv project repo in future. Change-Id: I87543d81c9df70d99c5001fbdf646b202c19f423 Signed-off-by: Yunhong Jiang <yunhong.jiang@intel.com>
Diffstat (limited to 'kernel/drivers/md/persistent-data')
-rw-r--r--kernel/drivers/md/persistent-data/Kconfig18
-rw-r--r--kernel/drivers/md/persistent-data/Makefile12
-rw-r--r--kernel/drivers/md/persistent-data/dm-array.c821
-rw-r--r--kernel/drivers/md/persistent-data/dm-array.h166
-rw-r--r--kernel/drivers/md/persistent-data/dm-bitset.c171
-rw-r--r--kernel/drivers/md/persistent-data/dm-bitset.h166
-rw-r--r--kernel/drivers/md/persistent-data/dm-block-manager.c636
-rw-r--r--kernel/drivers/md/persistent-data/dm-block-manager.h133
-rw-r--r--kernel/drivers/md/persistent-data/dm-btree-internal.h141
-rw-r--r--kernel/drivers/md/persistent-data/dm-btree-remove.c592
-rw-r--r--kernel/drivers/md/persistent-data/dm-btree-spine.c251
-rw-r--r--kernel/drivers/md/persistent-data/dm-btree.c892
-rw-r--r--kernel/drivers/md/persistent-data/dm-btree.h162
-rw-r--r--kernel/drivers/md/persistent-data/dm-persistent-data-internal.h19
-rw-r--r--kernel/drivers/md/persistent-data/dm-space-map-common.c751
-rw-r--r--kernel/drivers/md/persistent-data/dm-space-map-common.h127
-rw-r--r--kernel/drivers/md/persistent-data/dm-space-map-disk.c305
-rw-r--r--kernel/drivers/md/persistent-data/dm-space-map-disk.h25
-rw-r--r--kernel/drivers/md/persistent-data/dm-space-map-metadata.c798
-rw-r--r--kernel/drivers/md/persistent-data/dm-space-map-metadata.h44
-rw-r--r--kernel/drivers/md/persistent-data/dm-space-map.h157
-rw-r--r--kernel/drivers/md/persistent-data/dm-transaction-manager.c455
-rw-r--r--kernel/drivers/md/persistent-data/dm-transaction-manager.h137
23 files changed, 6979 insertions, 0 deletions
diff --git a/kernel/drivers/md/persistent-data/Kconfig b/kernel/drivers/md/persistent-data/Kconfig
new file mode 100644
index 000000000..78c74bb71
--- /dev/null
+++ b/kernel/drivers/md/persistent-data/Kconfig
@@ -0,0 +1,18 @@
+config DM_PERSISTENT_DATA
+ tristate
+ depends on BLK_DEV_DM
+ select LIBCRC32C
+ select DM_BUFIO
+ ---help---
+ Library providing immutable on-disk data structure support for
+ device-mapper targets such as the thin provisioning target.
+
+config DM_DEBUG_BLOCK_STACK_TRACING
+ bool "Keep stack trace of persistent data block lock holders"
+ depends on STACKTRACE_SUPPORT && DM_PERSISTENT_DATA
+ select STACKTRACE
+ ---help---
+ Enable this for messages that may help debug problems with the
+ block manager locking used by thin provisioning and caching.
+
+ If unsure, say N.
diff --git a/kernel/drivers/md/persistent-data/Makefile b/kernel/drivers/md/persistent-data/Makefile
new file mode 100644
index 000000000..ff528792c
--- /dev/null
+++ b/kernel/drivers/md/persistent-data/Makefile
@@ -0,0 +1,12 @@
+obj-$(CONFIG_DM_PERSISTENT_DATA) += dm-persistent-data.o
+dm-persistent-data-objs := \
+ dm-array.o \
+ dm-bitset.o \
+ dm-block-manager.o \
+ dm-space-map-common.o \
+ dm-space-map-disk.o \
+ dm-space-map-metadata.o \
+ dm-transaction-manager.o \
+ dm-btree.o \
+ dm-btree-remove.o \
+ dm-btree-spine.o
diff --git a/kernel/drivers/md/persistent-data/dm-array.c b/kernel/drivers/md/persistent-data/dm-array.c
new file mode 100644
index 000000000..e64b61ad0
--- /dev/null
+++ b/kernel/drivers/md/persistent-data/dm-array.c
@@ -0,0 +1,821 @@
+/*
+ * Copyright (C) 2012 Red Hat, Inc.
+ *
+ * This file is released under the GPL.
+ */
+
+#include "dm-array.h"
+#include "dm-space-map.h"
+#include "dm-transaction-manager.h"
+
+#include <linux/export.h>
+#include <linux/device-mapper.h>
+
+#define DM_MSG_PREFIX "array"
+
+/*----------------------------------------------------------------*/
+
+/*
+ * The array is implemented as a fully populated btree, which points to
+ * blocks that contain the packed values. This is more space efficient
+ * than just using a btree since we don't store 1 key per value.
+ */
+struct array_block {
+ __le32 csum;
+ __le32 max_entries;
+ __le32 nr_entries;
+ __le32 value_size;
+ __le64 blocknr; /* Block this node is supposed to live in. */
+} __packed;
+
+/*----------------------------------------------------------------*/
+
+/*
+ * Validator methods. As usual we calculate a checksum, and also write the
+ * block location into the header (paranoia about ssds remapping areas by
+ * mistake).
+ */
+#define CSUM_XOR 595846735
+
+static void array_block_prepare_for_write(struct dm_block_validator *v,
+ struct dm_block *b,
+ size_t size_of_block)
+{
+ struct array_block *bh_le = dm_block_data(b);
+
+ bh_le->blocknr = cpu_to_le64(dm_block_location(b));
+ bh_le->csum = cpu_to_le32(dm_bm_checksum(&bh_le->max_entries,
+ size_of_block - sizeof(__le32),
+ CSUM_XOR));
+}
+
+static int array_block_check(struct dm_block_validator *v,
+ struct dm_block *b,
+ size_t size_of_block)
+{
+ struct array_block *bh_le = dm_block_data(b);
+ __le32 csum_disk;
+
+ if (dm_block_location(b) != le64_to_cpu(bh_le->blocknr)) {
+ DMERR_LIMIT("array_block_check failed: blocknr %llu != wanted %llu",
+ (unsigned long long) le64_to_cpu(bh_le->blocknr),
+ (unsigned long long) dm_block_location(b));
+ return -ENOTBLK;
+ }
+
+ csum_disk = cpu_to_le32(dm_bm_checksum(&bh_le->max_entries,
+ size_of_block - sizeof(__le32),
+ CSUM_XOR));
+ if (csum_disk != bh_le->csum) {
+ DMERR_LIMIT("array_block_check failed: csum %u != wanted %u",
+ (unsigned) le32_to_cpu(csum_disk),
+ (unsigned) le32_to_cpu(bh_le->csum));
+ return -EILSEQ;
+ }
+
+ return 0;
+}
+
+static struct dm_block_validator array_validator = {
+ .name = "array",
+ .prepare_for_write = array_block_prepare_for_write,
+ .check = array_block_check
+};
+
+/*----------------------------------------------------------------*/
+
+/*
+ * Functions for manipulating the array blocks.
+ */
+
+/*
+ * Returns a pointer to a value within an array block.
+ *
+ * index - The index into _this_ specific block.
+ */
+static void *element_at(struct dm_array_info *info, struct array_block *ab,
+ unsigned index)
+{
+ unsigned char *entry = (unsigned char *) (ab + 1);
+
+ entry += index * info->value_type.size;
+
+ return entry;
+}
+
+/*
+ * Utility function that calls one of the value_type methods on every value
+ * in an array block.
+ */
+static void on_entries(struct dm_array_info *info, struct array_block *ab,
+ void (*fn)(void *, const void *))
+{
+ unsigned i, nr_entries = le32_to_cpu(ab->nr_entries);
+
+ for (i = 0; i < nr_entries; i++)
+ fn(info->value_type.context, element_at(info, ab, i));
+}
+
+/*
+ * Increment every value in an array block.
+ */
+static void inc_ablock_entries(struct dm_array_info *info, struct array_block *ab)
+{
+ struct dm_btree_value_type *vt = &info->value_type;
+
+ if (vt->inc)
+ on_entries(info, ab, vt->inc);
+}
+
+/*
+ * Decrement every value in an array block.
+ */
+static void dec_ablock_entries(struct dm_array_info *info, struct array_block *ab)
+{
+ struct dm_btree_value_type *vt = &info->value_type;
+
+ if (vt->dec)
+ on_entries(info, ab, vt->dec);
+}
+
+/*
+ * Each array block can hold this many values.
+ */
+static uint32_t calc_max_entries(size_t value_size, size_t size_of_block)
+{
+ return (size_of_block - sizeof(struct array_block)) / value_size;
+}
+
+/*
+ * Allocate a new array block. The caller will need to unlock block.
+ */
+static int alloc_ablock(struct dm_array_info *info, size_t size_of_block,
+ uint32_t max_entries,
+ struct dm_block **block, struct array_block **ab)
+{
+ int r;
+
+ r = dm_tm_new_block(info->btree_info.tm, &array_validator, block);
+ if (r)
+ return r;
+
+ (*ab) = dm_block_data(*block);
+ (*ab)->max_entries = cpu_to_le32(max_entries);
+ (*ab)->nr_entries = cpu_to_le32(0);
+ (*ab)->value_size = cpu_to_le32(info->value_type.size);
+
+ return 0;
+}
+
+/*
+ * Pad an array block out with a particular value. Every instance will
+ * cause an increment of the value_type. new_nr must always be more than
+ * the current number of entries.
+ */
+static void fill_ablock(struct dm_array_info *info, struct array_block *ab,
+ const void *value, unsigned new_nr)
+{
+ unsigned i;
+ uint32_t nr_entries;
+ struct dm_btree_value_type *vt = &info->value_type;
+
+ BUG_ON(new_nr > le32_to_cpu(ab->max_entries));
+ BUG_ON(new_nr < le32_to_cpu(ab->nr_entries));
+
+ nr_entries = le32_to_cpu(ab->nr_entries);
+ for (i = nr_entries; i < new_nr; i++) {
+ if (vt->inc)
+ vt->inc(vt->context, value);
+ memcpy(element_at(info, ab, i), value, vt->size);
+ }
+ ab->nr_entries = cpu_to_le32(new_nr);
+}
+
+/*
+ * Remove some entries from the back of an array block. Every value
+ * removed will be decremented. new_nr must be <= the current number of
+ * entries.
+ */
+static void trim_ablock(struct dm_array_info *info, struct array_block *ab,
+ unsigned new_nr)
+{
+ unsigned i;
+ uint32_t nr_entries;
+ struct dm_btree_value_type *vt = &info->value_type;
+
+ BUG_ON(new_nr > le32_to_cpu(ab->max_entries));
+ BUG_ON(new_nr > le32_to_cpu(ab->nr_entries));
+
+ nr_entries = le32_to_cpu(ab->nr_entries);
+ for (i = nr_entries; i > new_nr; i--)
+ if (vt->dec)
+ vt->dec(vt->context, element_at(info, ab, i - 1));
+ ab->nr_entries = cpu_to_le32(new_nr);
+}
+
+/*
+ * Read locks a block, and coerces it to an array block. The caller must
+ * unlock 'block' when finished.
+ */
+static int get_ablock(struct dm_array_info *info, dm_block_t b,
+ struct dm_block **block, struct array_block **ab)
+{
+ int r;
+
+ r = dm_tm_read_lock(info->btree_info.tm, b, &array_validator, block);
+ if (r)
+ return r;
+
+ *ab = dm_block_data(*block);
+ return 0;
+}
+
+/*
+ * Unlocks an array block.
+ */
+static int unlock_ablock(struct dm_array_info *info, struct dm_block *block)
+{
+ return dm_tm_unlock(info->btree_info.tm, block);
+}
+
+/*----------------------------------------------------------------*/
+
+/*
+ * Btree manipulation.
+ */
+
+/*
+ * Looks up an array block in the btree, and then read locks it.
+ *
+ * index is the index of the index of the array_block, (ie. the array index
+ * / max_entries).
+ */
+static int lookup_ablock(struct dm_array_info *info, dm_block_t root,
+ unsigned index, struct dm_block **block,
+ struct array_block **ab)
+{
+ int r;
+ uint64_t key = index;
+ __le64 block_le;
+
+ r = dm_btree_lookup(&info->btree_info, root, &key, &block_le);
+ if (r)
+ return r;
+
+ return get_ablock(info, le64_to_cpu(block_le), block, ab);
+}
+
+/*
+ * Insert an array block into the btree. The block is _not_ unlocked.
+ */
+static int insert_ablock(struct dm_array_info *info, uint64_t index,
+ struct dm_block *block, dm_block_t *root)
+{
+ __le64 block_le = cpu_to_le64(dm_block_location(block));
+
+ __dm_bless_for_disk(block_le);
+ return dm_btree_insert(&info->btree_info, *root, &index, &block_le, root);
+}
+
+/*
+ * Looks up an array block in the btree. Then shadows it, and updates the
+ * btree to point to this new shadow. 'root' is an input/output parameter
+ * for both the current root block, and the new one.
+ */
+static int shadow_ablock(struct dm_array_info *info, dm_block_t *root,
+ unsigned index, struct dm_block **block,
+ struct array_block **ab)
+{
+ int r, inc;
+ uint64_t key = index;
+ dm_block_t b;
+ __le64 block_le;
+
+ /*
+ * lookup
+ */
+ r = dm_btree_lookup(&info->btree_info, *root, &key, &block_le);
+ if (r)
+ return r;
+ b = le64_to_cpu(block_le);
+
+ /*
+ * shadow
+ */
+ r = dm_tm_shadow_block(info->btree_info.tm, b,
+ &array_validator, block, &inc);
+ if (r)
+ return r;
+
+ *ab = dm_block_data(*block);
+ if (inc)
+ inc_ablock_entries(info, *ab);
+
+ /*
+ * Reinsert.
+ *
+ * The shadow op will often be a noop. Only insert if it really
+ * copied data.
+ */
+ if (dm_block_location(*block) != b) {
+ /*
+ * dm_tm_shadow_block will have already decremented the old
+ * block, but it is still referenced by the btree. We
+ * increment to stop the insert decrementing it below zero
+ * when overwriting the old value.
+ */
+ dm_tm_inc(info->btree_info.tm, b);
+ r = insert_ablock(info, index, *block, root);
+ }
+
+ return r;
+}
+
+/*
+ * Allocate an new array block, and fill it with some values.
+ */
+static int insert_new_ablock(struct dm_array_info *info, size_t size_of_block,
+ uint32_t max_entries,
+ unsigned block_index, uint32_t nr,
+ const void *value, dm_block_t *root)
+{
+ int r;
+ struct dm_block *block;
+ struct array_block *ab;
+
+ r = alloc_ablock(info, size_of_block, max_entries, &block, &ab);
+ if (r)
+ return r;
+
+ fill_ablock(info, ab, value, nr);
+ r = insert_ablock(info, block_index, block, root);
+ unlock_ablock(info, block);
+
+ return r;
+}
+
+static int insert_full_ablocks(struct dm_array_info *info, size_t size_of_block,
+ unsigned begin_block, unsigned end_block,
+ unsigned max_entries, const void *value,
+ dm_block_t *root)
+{
+ int r = 0;
+
+ for (; !r && begin_block != end_block; begin_block++)
+ r = insert_new_ablock(info, size_of_block, max_entries, begin_block, max_entries, value, root);
+
+ return r;
+}
+
+/*
+ * There are a bunch of functions involved with resizing an array. This
+ * structure holds information that commonly needed by them. Purely here
+ * to reduce parameter count.
+ */
+struct resize {
+ /*
+ * Describes the array.
+ */
+ struct dm_array_info *info;
+
+ /*
+ * The current root of the array. This gets updated.
+ */
+ dm_block_t root;
+
+ /*
+ * Metadata block size. Used to calculate the nr entries in an
+ * array block.
+ */
+ size_t size_of_block;
+
+ /*
+ * Maximum nr entries in an array block.
+ */
+ unsigned max_entries;
+
+ /*
+ * nr of completely full blocks in the array.
+ *
+ * 'old' refers to before the resize, 'new' after.
+ */
+ unsigned old_nr_full_blocks, new_nr_full_blocks;
+
+ /*
+ * Number of entries in the final block. 0 iff only full blocks in
+ * the array.
+ */
+ unsigned old_nr_entries_in_last_block, new_nr_entries_in_last_block;
+
+ /*
+ * The default value used when growing the array.
+ */
+ const void *value;
+};
+
+/*
+ * Removes a consecutive set of array blocks from the btree. The values
+ * in block are decremented as a side effect of the btree remove.
+ *
+ * begin_index - the index of the first array block to remove.
+ * end_index - the one-past-the-end value. ie. this block is not removed.
+ */
+static int drop_blocks(struct resize *resize, unsigned begin_index,
+ unsigned end_index)
+{
+ int r;
+
+ while (begin_index != end_index) {
+ uint64_t key = begin_index++;
+ r = dm_btree_remove(&resize->info->btree_info, resize->root,
+ &key, &resize->root);
+ if (r)
+ return r;
+ }
+
+ return 0;
+}
+
+/*
+ * Calculates how many blocks are needed for the array.
+ */
+static unsigned total_nr_blocks_needed(unsigned nr_full_blocks,
+ unsigned nr_entries_in_last_block)
+{
+ return nr_full_blocks + (nr_entries_in_last_block ? 1 : 0);
+}
+
+/*
+ * Shrink an array.
+ */
+static int shrink(struct resize *resize)
+{
+ int r;
+ unsigned begin, end;
+ struct dm_block *block;
+ struct array_block *ab;
+
+ /*
+ * Lose some blocks from the back?
+ */
+ if (resize->new_nr_full_blocks < resize->old_nr_full_blocks) {
+ begin = total_nr_blocks_needed(resize->new_nr_full_blocks,
+ resize->new_nr_entries_in_last_block);
+ end = total_nr_blocks_needed(resize->old_nr_full_blocks,
+ resize->old_nr_entries_in_last_block);
+
+ r = drop_blocks(resize, begin, end);
+ if (r)
+ return r;
+ }
+
+ /*
+ * Trim the new tail block
+ */
+ if (resize->new_nr_entries_in_last_block) {
+ r = shadow_ablock(resize->info, &resize->root,
+ resize->new_nr_full_blocks, &block, &ab);
+ if (r)
+ return r;
+
+ trim_ablock(resize->info, ab, resize->new_nr_entries_in_last_block);
+ unlock_ablock(resize->info, block);
+ }
+
+ return 0;
+}
+
+/*
+ * Grow an array.
+ */
+static int grow_extend_tail_block(struct resize *resize, uint32_t new_nr_entries)
+{
+ int r;
+ struct dm_block *block;
+ struct array_block *ab;
+
+ r = shadow_ablock(resize->info, &resize->root,
+ resize->old_nr_full_blocks, &block, &ab);
+ if (r)
+ return r;
+
+ fill_ablock(resize->info, ab, resize->value, new_nr_entries);
+ unlock_ablock(resize->info, block);
+
+ return r;
+}
+
+static int grow_add_tail_block(struct resize *resize)
+{
+ return insert_new_ablock(resize->info, resize->size_of_block,
+ resize->max_entries,
+ resize->new_nr_full_blocks,
+ resize->new_nr_entries_in_last_block,
+ resize->value, &resize->root);
+}
+
+static int grow_needs_more_blocks(struct resize *resize)
+{
+ int r;
+ unsigned old_nr_blocks = resize->old_nr_full_blocks;
+
+ if (resize->old_nr_entries_in_last_block > 0) {
+ old_nr_blocks++;
+
+ r = grow_extend_tail_block(resize, resize->max_entries);
+ if (r)
+ return r;
+ }
+
+ r = insert_full_ablocks(resize->info, resize->size_of_block,
+ old_nr_blocks,
+ resize->new_nr_full_blocks,
+ resize->max_entries, resize->value,
+ &resize->root);
+ if (r)
+ return r;
+
+ if (resize->new_nr_entries_in_last_block)
+ r = grow_add_tail_block(resize);
+
+ return r;
+}
+
+static int grow(struct resize *resize)
+{
+ if (resize->new_nr_full_blocks > resize->old_nr_full_blocks)
+ return grow_needs_more_blocks(resize);
+
+ else if (resize->old_nr_entries_in_last_block)
+ return grow_extend_tail_block(resize, resize->new_nr_entries_in_last_block);
+
+ else
+ return grow_add_tail_block(resize);
+}
+
+/*----------------------------------------------------------------*/
+
+/*
+ * These are the value_type functions for the btree elements, which point
+ * to array blocks.
+ */
+static void block_inc(void *context, const void *value)
+{
+ __le64 block_le;
+ struct dm_array_info *info = context;
+
+ memcpy(&block_le, value, sizeof(block_le));
+ dm_tm_inc(info->btree_info.tm, le64_to_cpu(block_le));
+}
+
+static void block_dec(void *context, const void *value)
+{
+ int r;
+ uint64_t b;
+ __le64 block_le;
+ uint32_t ref_count;
+ struct dm_block *block;
+ struct array_block *ab;
+ struct dm_array_info *info = context;
+
+ memcpy(&block_le, value, sizeof(block_le));
+ b = le64_to_cpu(block_le);
+
+ r = dm_tm_ref(info->btree_info.tm, b, &ref_count);
+ if (r) {
+ DMERR_LIMIT("couldn't get reference count for block %llu",
+ (unsigned long long) b);
+ return;
+ }
+
+ if (ref_count == 1) {
+ /*
+ * We're about to drop the last reference to this ablock.
+ * So we need to decrement the ref count of the contents.
+ */
+ r = get_ablock(info, b, &block, &ab);
+ if (r) {
+ DMERR_LIMIT("couldn't get array block %llu",
+ (unsigned long long) b);
+ return;
+ }
+
+ dec_ablock_entries(info, ab);
+ unlock_ablock(info, block);
+ }
+
+ dm_tm_dec(info->btree_info.tm, b);
+}
+
+static int block_equal(void *context, const void *value1, const void *value2)
+{
+ return !memcmp(value1, value2, sizeof(__le64));
+}
+
+/*----------------------------------------------------------------*/
+
+void dm_array_info_init(struct dm_array_info *info,
+ struct dm_transaction_manager *tm,
+ struct dm_btree_value_type *vt)
+{
+ struct dm_btree_value_type *bvt = &info->btree_info.value_type;
+
+ memcpy(&info->value_type, vt, sizeof(info->value_type));
+ info->btree_info.tm = tm;
+ info->btree_info.levels = 1;
+
+ bvt->context = info;
+ bvt->size = sizeof(__le64);
+ bvt->inc = block_inc;
+ bvt->dec = block_dec;
+ bvt->equal = block_equal;
+}
+EXPORT_SYMBOL_GPL(dm_array_info_init);
+
+int dm_array_empty(struct dm_array_info *info, dm_block_t *root)
+{
+ return dm_btree_empty(&info->btree_info, root);
+}
+EXPORT_SYMBOL_GPL(dm_array_empty);
+
+static int array_resize(struct dm_array_info *info, dm_block_t root,
+ uint32_t old_size, uint32_t new_size,
+ const void *value, dm_block_t *new_root)
+{
+ int r;
+ struct resize resize;
+
+ if (old_size == new_size) {
+ *new_root = root;
+ return 0;
+ }
+
+ resize.info = info;
+ resize.root = root;
+ resize.size_of_block = dm_bm_block_size(dm_tm_get_bm(info->btree_info.tm));
+ resize.max_entries = calc_max_entries(info->value_type.size,
+ resize.size_of_block);
+
+ resize.old_nr_full_blocks = old_size / resize.max_entries;
+ resize.old_nr_entries_in_last_block = old_size % resize.max_entries;
+ resize.new_nr_full_blocks = new_size / resize.max_entries;
+ resize.new_nr_entries_in_last_block = new_size % resize.max_entries;
+ resize.value = value;
+
+ r = ((new_size > old_size) ? grow : shrink)(&resize);
+ if (r)
+ return r;
+
+ *new_root = resize.root;
+ return 0;
+}
+
+int dm_array_resize(struct dm_array_info *info, dm_block_t root,
+ uint32_t old_size, uint32_t new_size,
+ const void *value, dm_block_t *new_root)
+ __dm_written_to_disk(value)
+{
+ int r = array_resize(info, root, old_size, new_size, value, new_root);
+ __dm_unbless_for_disk(value);
+ return r;
+}
+EXPORT_SYMBOL_GPL(dm_array_resize);
+
+int dm_array_del(struct dm_array_info *info, dm_block_t root)
+{
+ return dm_btree_del(&info->btree_info, root);
+}
+EXPORT_SYMBOL_GPL(dm_array_del);
+
+int dm_array_get_value(struct dm_array_info *info, dm_block_t root,
+ uint32_t index, void *value_le)
+{
+ int r;
+ struct dm_block *block;
+ struct array_block *ab;
+ size_t size_of_block;
+ unsigned entry, max_entries;
+
+ size_of_block = dm_bm_block_size(dm_tm_get_bm(info->btree_info.tm));
+ max_entries = calc_max_entries(info->value_type.size, size_of_block);
+
+ r = lookup_ablock(info, root, index / max_entries, &block, &ab);
+ if (r)
+ return r;
+
+ entry = index % max_entries;
+ if (entry >= le32_to_cpu(ab->nr_entries))
+ r = -ENODATA;
+ else
+ memcpy(value_le, element_at(info, ab, entry),
+ info->value_type.size);
+
+ unlock_ablock(info, block);
+ return r;
+}
+EXPORT_SYMBOL_GPL(dm_array_get_value);
+
+static int array_set_value(struct dm_array_info *info, dm_block_t root,
+ uint32_t index, const void *value, dm_block_t *new_root)
+{
+ int r;
+ struct dm_block *block;
+ struct array_block *ab;
+ size_t size_of_block;
+ unsigned max_entries;
+ unsigned entry;
+ void *old_value;
+ struct dm_btree_value_type *vt = &info->value_type;
+
+ size_of_block = dm_bm_block_size(dm_tm_get_bm(info->btree_info.tm));
+ max_entries = calc_max_entries(info->value_type.size, size_of_block);
+
+ r = shadow_ablock(info, &root, index / max_entries, &block, &ab);
+ if (r)
+ return r;
+ *new_root = root;
+
+ entry = index % max_entries;
+ if (entry >= le32_to_cpu(ab->nr_entries)) {
+ r = -ENODATA;
+ goto out;
+ }
+
+ old_value = element_at(info, ab, entry);
+ if (vt->dec &&
+ (!vt->equal || !vt->equal(vt->context, old_value, value))) {
+ vt->dec(vt->context, old_value);
+ if (vt->inc)
+ vt->inc(vt->context, value);
+ }
+
+ memcpy(old_value, value, info->value_type.size);
+
+out:
+ unlock_ablock(info, block);
+ return r;
+}
+
+int dm_array_set_value(struct dm_array_info *info, dm_block_t root,
+ uint32_t index, const void *value, dm_block_t *new_root)
+ __dm_written_to_disk(value)
+{
+ int r;
+
+ r = array_set_value(info, root, index, value, new_root);
+ __dm_unbless_for_disk(value);
+ return r;
+}
+EXPORT_SYMBOL_GPL(dm_array_set_value);
+
+struct walk_info {
+ struct dm_array_info *info;
+ int (*fn)(void *context, uint64_t key, void *leaf);
+ void *context;
+};
+
+static int walk_ablock(void *context, uint64_t *keys, void *leaf)
+{
+ struct walk_info *wi = context;
+
+ int r;
+ unsigned i;
+ __le64 block_le;
+ unsigned nr_entries, max_entries;
+ struct dm_block *block;
+ struct array_block *ab;
+
+ memcpy(&block_le, leaf, sizeof(block_le));
+ r = get_ablock(wi->info, le64_to_cpu(block_le), &block, &ab);
+ if (r)
+ return r;
+
+ max_entries = le32_to_cpu(ab->max_entries);
+ nr_entries = le32_to_cpu(ab->nr_entries);
+ for (i = 0; i < nr_entries; i++) {
+ r = wi->fn(wi->context, keys[0] * max_entries + i,
+ element_at(wi->info, ab, i));
+
+ if (r)
+ break;
+ }
+
+ unlock_ablock(wi->info, block);
+ return r;
+}
+
+int dm_array_walk(struct dm_array_info *info, dm_block_t root,
+ int (*fn)(void *, uint64_t key, void *leaf),
+ void *context)
+{
+ struct walk_info wi;
+
+ wi.info = info;
+ wi.fn = fn;
+ wi.context = context;
+
+ return dm_btree_walk(&info->btree_info, root, walk_ablock, &wi);
+}
+EXPORT_SYMBOL_GPL(dm_array_walk);
+
+/*----------------------------------------------------------------*/
diff --git a/kernel/drivers/md/persistent-data/dm-array.h b/kernel/drivers/md/persistent-data/dm-array.h
new file mode 100644
index 000000000..ea177d6fa
--- /dev/null
+++ b/kernel/drivers/md/persistent-data/dm-array.h
@@ -0,0 +1,166 @@
+/*
+ * Copyright (C) 2012 Red Hat, Inc.
+ *
+ * This file is released under the GPL.
+ */
+#ifndef _LINUX_DM_ARRAY_H
+#define _LINUX_DM_ARRAY_H
+
+#include "dm-btree.h"
+
+/*----------------------------------------------------------------*/
+
+/*
+ * The dm-array is a persistent version of an array. It packs the data
+ * more efficiently than a btree which will result in less disk space use,
+ * and a performance boost. The element get and set operations are still
+ * O(ln(n)), but with a much smaller constant.
+ *
+ * The value type structure is reused from the btree type to support proper
+ * reference counting of values.
+ *
+ * The arrays implicitly know their length, and bounds are checked for
+ * lookups and updated. It doesn't store this in an accessible place
+ * because it would waste a whole metadata block. Make sure you store the
+ * size along with the array root in your encompassing data.
+ *
+ * Array entries are indexed via an unsigned integer starting from zero.
+ * Arrays are not sparse; if you resize an array to have 'n' entries then
+ * 'n - 1' will be the last valid index.
+ *
+ * Typical use:
+ *
+ * a) initialise a dm_array_info structure. This describes the array
+ * values and ties it into a specific transaction manager. It holds no
+ * instance data; the same info can be used for many similar arrays if
+ * you wish.
+ *
+ * b) Get yourself a root. The root is the index of a block of data on the
+ * disk that holds a particular instance of an array. You may have a
+ * pre existing root in your metadata that you wish to use, or you may
+ * want to create a brand new, empty array with dm_array_empty().
+ *
+ * Like the other data structures in this library, dm_array objects are
+ * immutable between transactions. Update functions will return you the
+ * root for a _new_ array. If you've incremented the old root, via
+ * dm_tm_inc(), before calling the update function you may continue to use
+ * it in parallel with the new root.
+ *
+ * c) resize an array with dm_array_resize().
+ *
+ * d) Get a value from the array with dm_array_get_value().
+ *
+ * e) Set a value in the array with dm_array_set_value().
+ *
+ * f) Walk an array of values in index order with dm_array_walk(). More
+ * efficient than making many calls to dm_array_get_value().
+ *
+ * g) Destroy the array with dm_array_del(). This tells the transaction
+ * manager that you're no longer using this data structure so it can
+ * recycle it's blocks. (dm_array_dec() would be a better name for it,
+ * but del is in keeping with dm_btree_del()).
+ */
+
+/*
+ * Describes an array. Don't initialise this structure yourself, use the
+ * init function below.
+ */
+struct dm_array_info {
+ struct dm_transaction_manager *tm;
+ struct dm_btree_value_type value_type;
+ struct dm_btree_info btree_info;
+};
+
+/*
+ * Sets up a dm_array_info structure. You don't need to do anything with
+ * this structure when you finish using it.
+ *
+ * info - the structure being filled in.
+ * tm - the transaction manager that should supervise this structure.
+ * vt - describes the leaf values.
+ */
+void dm_array_info_init(struct dm_array_info *info,
+ struct dm_transaction_manager *tm,
+ struct dm_btree_value_type *vt);
+
+/*
+ * Create an empty, zero length array.
+ *
+ * info - describes the array
+ * root - on success this will be filled out with the root block
+ */
+int dm_array_empty(struct dm_array_info *info, dm_block_t *root);
+
+/*
+ * Resizes the array.
+ *
+ * info - describes the array
+ * root - the root block of the array on disk
+ * old_size - the caller is responsible for remembering the size of
+ * the array
+ * new_size - can be bigger or smaller than old_size
+ * value - if we're growing the array the new entries will have this value
+ * new_root - on success, points to the new root block
+ *
+ * If growing the inc function for 'value' will be called the appropriate
+ * number of times. So if the caller is holding a reference they may want
+ * to drop it.
+ */
+int dm_array_resize(struct dm_array_info *info, dm_block_t root,
+ uint32_t old_size, uint32_t new_size,
+ const void *value, dm_block_t *new_root)
+ __dm_written_to_disk(value);
+
+/*
+ * Frees a whole array. The value_type's decrement operation will be called
+ * for all values in the array
+ */
+int dm_array_del(struct dm_array_info *info, dm_block_t root);
+
+/*
+ * Lookup a value in the array
+ *
+ * info - describes the array
+ * root - root block of the array
+ * index - array index
+ * value - the value to be read. Will be in on-disk format of course.
+ *
+ * -ENODATA will be returned if the index is out of bounds.
+ */
+int dm_array_get_value(struct dm_array_info *info, dm_block_t root,
+ uint32_t index, void *value);
+
+/*
+ * Set an entry in the array.
+ *
+ * info - describes the array
+ * root - root block of the array
+ * index - array index
+ * value - value to be written to disk. Make sure you confirm the value is
+ * in on-disk format with__dm_bless_for_disk() before calling.
+ * new_root - the new root block
+ *
+ * The old value being overwritten will be decremented, the new value
+ * incremented.
+ *
+ * -ENODATA will be returned if the index is out of bounds.
+ */
+int dm_array_set_value(struct dm_array_info *info, dm_block_t root,
+ uint32_t index, const void *value, dm_block_t *new_root)
+ __dm_written_to_disk(value);
+
+/*
+ * Walk through all the entries in an array.
+ *
+ * info - describes the array
+ * root - root block of the array
+ * fn - called back for every element
+ * context - passed to the callback
+ */
+int dm_array_walk(struct dm_array_info *info, dm_block_t root,
+ int (*fn)(void *context, uint64_t key, void *leaf),
+ void *context);
+
+/*----------------------------------------------------------------*/
+
+#endif /* _LINUX_DM_ARRAY_H */
diff --git a/kernel/drivers/md/persistent-data/dm-bitset.c b/kernel/drivers/md/persistent-data/dm-bitset.c
new file mode 100644
index 000000000..36f7cc2c7
--- /dev/null
+++ b/kernel/drivers/md/persistent-data/dm-bitset.c
@@ -0,0 +1,171 @@
+/*
+ * Copyright (C) 2012 Red Hat, Inc.
+ *
+ * This file is released under the GPL.
+ */
+
+#include "dm-bitset.h"
+#include "dm-transaction-manager.h"
+
+#include <linux/export.h>
+#include <linux/device-mapper.h>
+
+#define DM_MSG_PREFIX "bitset"
+#define BITS_PER_ARRAY_ENTRY 64
+
+/*----------------------------------------------------------------*/
+
+static struct dm_btree_value_type bitset_bvt = {
+ .context = NULL,
+ .size = sizeof(__le64),
+ .inc = NULL,
+ .dec = NULL,
+ .equal = NULL,
+};
+
+/*----------------------------------------------------------------*/
+
+void dm_disk_bitset_init(struct dm_transaction_manager *tm,
+ struct dm_disk_bitset *info)
+{
+ dm_array_info_init(&info->array_info, tm, &bitset_bvt);
+ info->current_index_set = false;
+}
+EXPORT_SYMBOL_GPL(dm_disk_bitset_init);
+
+int dm_bitset_empty(struct dm_disk_bitset *info, dm_block_t *root)
+{
+ return dm_array_empty(&info->array_info, root);
+}
+EXPORT_SYMBOL_GPL(dm_bitset_empty);
+
+int dm_bitset_resize(struct dm_disk_bitset *info, dm_block_t root,
+ uint32_t old_nr_entries, uint32_t new_nr_entries,
+ bool default_value, dm_block_t *new_root)
+{
+ uint32_t old_blocks = dm_div_up(old_nr_entries, BITS_PER_ARRAY_ENTRY);
+ uint32_t new_blocks = dm_div_up(new_nr_entries, BITS_PER_ARRAY_ENTRY);
+ __le64 value = default_value ? cpu_to_le64(~0) : cpu_to_le64(0);
+
+ __dm_bless_for_disk(&value);
+ return dm_array_resize(&info->array_info, root, old_blocks, new_blocks,
+ &value, new_root);
+}
+EXPORT_SYMBOL_GPL(dm_bitset_resize);
+
+int dm_bitset_del(struct dm_disk_bitset *info, dm_block_t root)
+{
+ return dm_array_del(&info->array_info, root);
+}
+EXPORT_SYMBOL_GPL(dm_bitset_del);
+
+int dm_bitset_flush(struct dm_disk_bitset *info, dm_block_t root,
+ dm_block_t *new_root)
+{
+ int r;
+ __le64 value;
+
+ if (!info->current_index_set || !info->dirty)
+ return 0;
+
+ value = cpu_to_le64(info->current_bits);
+
+ __dm_bless_for_disk(&value);
+ r = dm_array_set_value(&info->array_info, root, info->current_index,
+ &value, new_root);
+ if (r)
+ return r;
+
+ info->current_index_set = false;
+ info->dirty = false;
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(dm_bitset_flush);
+
+static int read_bits(struct dm_disk_bitset *info, dm_block_t root,
+ uint32_t array_index)
+{
+ int r;
+ __le64 value;
+
+ r = dm_array_get_value(&info->array_info, root, array_index, &value);
+ if (r)
+ return r;
+
+ info->current_bits = le64_to_cpu(value);
+ info->current_index_set = true;
+ info->current_index = array_index;
+ info->dirty = false;
+
+ return 0;
+}
+
+static int get_array_entry(struct dm_disk_bitset *info, dm_block_t root,
+ uint32_t index, dm_block_t *new_root)
+{
+ int r;
+ unsigned array_index = index / BITS_PER_ARRAY_ENTRY;
+
+ if (info->current_index_set) {
+ if (info->current_index == array_index)
+ return 0;
+
+ r = dm_bitset_flush(info, root, new_root);
+ if (r)
+ return r;
+ }
+
+ return read_bits(info, root, array_index);
+}
+
+int dm_bitset_set_bit(struct dm_disk_bitset *info, dm_block_t root,
+ uint32_t index, dm_block_t *new_root)
+{
+ int r;
+ unsigned b = index % BITS_PER_ARRAY_ENTRY;
+
+ r = get_array_entry(info, root, index, new_root);
+ if (r)
+ return r;
+
+ set_bit(b, (unsigned long *) &info->current_bits);
+ info->dirty = true;
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(dm_bitset_set_bit);
+
+int dm_bitset_clear_bit(struct dm_disk_bitset *info, dm_block_t root,
+ uint32_t index, dm_block_t *new_root)
+{
+ int r;
+ unsigned b = index % BITS_PER_ARRAY_ENTRY;
+
+ r = get_array_entry(info, root, index, new_root);
+ if (r)
+ return r;
+
+ clear_bit(b, (unsigned long *) &info->current_bits);
+ info->dirty = true;
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(dm_bitset_clear_bit);
+
+int dm_bitset_test_bit(struct dm_disk_bitset *info, dm_block_t root,
+ uint32_t index, dm_block_t *new_root, bool *result)
+{
+ int r;
+ unsigned b = index % BITS_PER_ARRAY_ENTRY;
+
+ r = get_array_entry(info, root, index, new_root);
+ if (r)
+ return r;
+
+ *result = test_bit(b, (unsigned long *) &info->current_bits);
+ return 0;
+}
+EXPORT_SYMBOL_GPL(dm_bitset_test_bit);
+
+/*----------------------------------------------------------------*/
diff --git a/kernel/drivers/md/persistent-data/dm-bitset.h b/kernel/drivers/md/persistent-data/dm-bitset.h
new file mode 100644
index 000000000..c2287d672
--- /dev/null
+++ b/kernel/drivers/md/persistent-data/dm-bitset.h
@@ -0,0 +1,166 @@
+/*
+ * Copyright (C) 2012 Red Hat, Inc.
+ *
+ * This file is released under the GPL.
+ */
+#ifndef _LINUX_DM_BITSET_H
+#define _LINUX_DM_BITSET_H
+
+#include "dm-array.h"
+
+/*----------------------------------------------------------------*/
+
+/*
+ * This bitset type is a thin wrapper round a dm_array of 64bit words. It
+ * uses a tiny, one word cache to reduce the number of array lookups and so
+ * increase performance.
+ *
+ * Like the dm-array that it's based on, the caller needs to keep track of
+ * the size of the bitset separately. The underlying dm-array implicitly
+ * knows how many words it's storing and will return -ENODATA if you try
+ * and access an out of bounds word. However, an out of bounds bit in the
+ * final word will _not_ be detected, you have been warned.
+ *
+ * Bits are indexed from zero.
+
+ * Typical use:
+ *
+ * a) Initialise a dm_disk_bitset structure with dm_disk_bitset_init().
+ * This describes the bitset and includes the cache. It's not called it
+ * dm_bitset_info in line with other data structures because it does
+ * include instance data.
+ *
+ * b) Get yourself a root. The root is the index of a block of data on the
+ * disk that holds a particular instance of an bitset. You may have a
+ * pre existing root in your metadata that you wish to use, or you may
+ * want to create a brand new, empty bitset with dm_bitset_empty().
+ *
+ * Like the other data structures in this library, dm_bitset objects are
+ * immutable between transactions. Update functions will return you the
+ * root for a _new_ array. If you've incremented the old root, via
+ * dm_tm_inc(), before calling the update function you may continue to use
+ * it in parallel with the new root.
+ *
+ * Even read operations may trigger the cache to be flushed and as such
+ * return a root for a new, updated bitset.
+ *
+ * c) resize a bitset with dm_bitset_resize().
+ *
+ * d) Set a bit with dm_bitset_set_bit().
+ *
+ * e) Clear a bit with dm_bitset_clear_bit().
+ *
+ * f) Test a bit with dm_bitset_test_bit().
+ *
+ * g) Flush all updates from the cache with dm_bitset_flush().
+ *
+ * h) Destroy the bitset with dm_bitset_del(). This tells the transaction
+ * manager that you're no longer using this data structure so it can
+ * recycle it's blocks. (dm_bitset_dec() would be a better name for it,
+ * but del is in keeping with dm_btree_del()).
+ */
+
+/*
+ * Opaque object. Unlike dm_array_info, you should have one of these per
+ * bitset. Initialise with dm_disk_bitset_init().
+ */
+struct dm_disk_bitset {
+ struct dm_array_info array_info;
+
+ uint32_t current_index;
+ uint64_t current_bits;
+
+ bool current_index_set:1;
+ bool dirty:1;
+};
+
+/*
+ * Sets up a dm_disk_bitset structure. You don't need to do anything with
+ * this structure when you finish using it.
+ *
+ * tm - the transaction manager that should supervise this structure
+ * info - the structure being initialised
+ */
+void dm_disk_bitset_init(struct dm_transaction_manager *tm,
+ struct dm_disk_bitset *info);
+
+/*
+ * Create an empty, zero length bitset.
+ *
+ * info - describes the bitset
+ * new_root - on success, points to the new root block
+ */
+int dm_bitset_empty(struct dm_disk_bitset *info, dm_block_t *new_root);
+
+/*
+ * Resize the bitset.
+ *
+ * info - describes the bitset
+ * old_root - the root block of the array on disk
+ * old_nr_entries - the number of bits in the old bitset
+ * new_nr_entries - the number of bits you want in the new bitset
+ * default_value - the value for any new bits
+ * new_root - on success, points to the new root block
+ */
+int dm_bitset_resize(struct dm_disk_bitset *info, dm_block_t old_root,
+ uint32_t old_nr_entries, uint32_t new_nr_entries,
+ bool default_value, dm_block_t *new_root);
+
+/*
+ * Frees the bitset.
+ */
+int dm_bitset_del(struct dm_disk_bitset *info, dm_block_t root);
+
+/*
+ * Set a bit.
+ *
+ * info - describes the bitset
+ * root - the root block of the bitset
+ * index - the bit index
+ * new_root - on success, points to the new root block
+ *
+ * -ENODATA will be returned if the index is out of bounds.
+ */
+int dm_bitset_set_bit(struct dm_disk_bitset *info, dm_block_t root,
+ uint32_t index, dm_block_t *new_root);
+
+/*
+ * Clears a bit.
+ *
+ * info - describes the bitset
+ * root - the root block of the bitset
+ * index - the bit index
+ * new_root - on success, points to the new root block
+ *
+ * -ENODATA will be returned if the index is out of bounds.
+ */
+int dm_bitset_clear_bit(struct dm_disk_bitset *info, dm_block_t root,
+ uint32_t index, dm_block_t *new_root);
+
+/*
+ * Tests a bit.
+ *
+ * info - describes the bitset
+ * root - the root block of the bitset
+ * index - the bit index
+ * new_root - on success, points to the new root block (cached values may have been written)
+ * result - the bit value you're after
+ *
+ * -ENODATA will be returned if the index is out of bounds.
+ */
+int dm_bitset_test_bit(struct dm_disk_bitset *info, dm_block_t root,
+ uint32_t index, dm_block_t *new_root, bool *result);
+
+/*
+ * Flush any cached changes to disk.
+ *
+ * info - describes the bitset
+ * root - the root block of the bitset
+ * new_root - on success, points to the new root block
+ */
+int dm_bitset_flush(struct dm_disk_bitset *info, dm_block_t root,
+ dm_block_t *new_root);
+
+/*----------------------------------------------------------------*/
+
+#endif /* _LINUX_DM_BITSET_H */
diff --git a/kernel/drivers/md/persistent-data/dm-block-manager.c b/kernel/drivers/md/persistent-data/dm-block-manager.c
new file mode 100644
index 000000000..087411c95
--- /dev/null
+++ b/kernel/drivers/md/persistent-data/dm-block-manager.c
@@ -0,0 +1,636 @@
+/*
+ * Copyright (C) 2011 Red Hat, Inc.
+ *
+ * This file is released under the GPL.
+ */
+#include "dm-block-manager.h"
+#include "dm-persistent-data-internal.h"
+#include "../dm-bufio.h"
+
+#include <linux/crc32c.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/rwsem.h>
+#include <linux/device-mapper.h>
+#include <linux/stacktrace.h>
+
+#define DM_MSG_PREFIX "block manager"
+
+/*----------------------------------------------------------------*/
+
+/*
+ * This is a read/write semaphore with a couple of differences.
+ *
+ * i) There is a restriction on the number of concurrent read locks that
+ * may be held at once. This is just an implementation detail.
+ *
+ * ii) Recursive locking attempts are detected and return EINVAL. A stack
+ * trace is also emitted for the previous lock acquisition.
+ *
+ * iii) Priority is given to write locks.
+ */
+#define MAX_HOLDERS 4
+#define MAX_STACK 10
+
+typedef unsigned long stack_entries[MAX_STACK];
+
+struct block_lock {
+ spinlock_t lock;
+ __s32 count;
+ struct list_head waiters;
+ struct task_struct *holders[MAX_HOLDERS];
+
+#ifdef CONFIG_DM_DEBUG_BLOCK_STACK_TRACING
+ struct stack_trace traces[MAX_HOLDERS];
+ stack_entries entries[MAX_HOLDERS];
+#endif
+};
+
+struct waiter {
+ struct list_head list;
+ struct task_struct *task;
+ int wants_write;
+};
+
+static unsigned __find_holder(struct block_lock *lock,
+ struct task_struct *task)
+{
+ unsigned i;
+
+ for (i = 0; i < MAX_HOLDERS; i++)
+ if (lock->holders[i] == task)
+ break;
+
+ BUG_ON(i == MAX_HOLDERS);
+ return i;
+}
+
+/* call this *after* you increment lock->count */
+static void __add_holder(struct block_lock *lock, struct task_struct *task)
+{
+ unsigned h = __find_holder(lock, NULL);
+#ifdef CONFIG_DM_DEBUG_BLOCK_STACK_TRACING
+ struct stack_trace *t;
+#endif
+
+ get_task_struct(task);
+ lock->holders[h] = task;
+
+#ifdef CONFIG_DM_DEBUG_BLOCK_STACK_TRACING
+ t = lock->traces + h;
+ t->nr_entries = 0;
+ t->max_entries = MAX_STACK;
+ t->entries = lock->entries[h];
+ t->skip = 2;
+ save_stack_trace(t);
+#endif
+}
+
+/* call this *before* you decrement lock->count */
+static void __del_holder(struct block_lock *lock, struct task_struct *task)
+{
+ unsigned h = __find_holder(lock, task);
+ lock->holders[h] = NULL;
+ put_task_struct(task);
+}
+
+static int __check_holder(struct block_lock *lock)
+{
+ unsigned i;
+#ifdef CONFIG_DM_DEBUG_BLOCK_STACK_TRACING
+ static struct stack_trace t;
+ static stack_entries entries;
+#endif
+
+ for (i = 0; i < MAX_HOLDERS; i++) {
+ if (lock->holders[i] == current) {
+ DMERR("recursive lock detected in metadata");
+#ifdef CONFIG_DM_DEBUG_BLOCK_STACK_TRACING
+ DMERR("previously held here:");
+ print_stack_trace(lock->traces + i, 4);
+
+ DMERR("subsequent acquisition attempted here:");
+ t.nr_entries = 0;
+ t.max_entries = MAX_STACK;
+ t.entries = entries;
+ t.skip = 3;
+ save_stack_trace(&t);
+ print_stack_trace(&t, 4);
+#endif
+ return -EINVAL;
+ }
+ }
+
+ return 0;
+}
+
+static void __wait(struct waiter *w)
+{
+ for (;;) {
+ set_task_state(current, TASK_UNINTERRUPTIBLE);
+
+ if (!w->task)
+ break;
+
+ schedule();
+ }
+
+ set_task_state(current, TASK_RUNNING);
+}
+
+static void __wake_waiter(struct waiter *w)
+{
+ struct task_struct *task;
+
+ list_del(&w->list);
+ task = w->task;
+ smp_mb();
+ w->task = NULL;
+ wake_up_process(task);
+}
+
+/*
+ * We either wake a few readers or a single writer.
+ */
+static void __wake_many(struct block_lock *lock)
+{
+ struct waiter *w, *tmp;
+
+ BUG_ON(lock->count < 0);
+ list_for_each_entry_safe(w, tmp, &lock->waiters, list) {
+ if (lock->count >= MAX_HOLDERS)
+ return;
+
+ if (w->wants_write) {
+ if (lock->count > 0)
+ return; /* still read locked */
+
+ lock->count = -1;
+ __add_holder(lock, w->task);
+ __wake_waiter(w);
+ return;
+ }
+
+ lock->count++;
+ __add_holder(lock, w->task);
+ __wake_waiter(w);
+ }
+}
+
+static void bl_init(struct block_lock *lock)
+{
+ int i;
+
+ spin_lock_init(&lock->lock);
+ lock->count = 0;
+ INIT_LIST_HEAD(&lock->waiters);
+ for (i = 0; i < MAX_HOLDERS; i++)
+ lock->holders[i] = NULL;
+}
+
+static int __available_for_read(struct block_lock *lock)
+{
+ return lock->count >= 0 &&
+ lock->count < MAX_HOLDERS &&
+ list_empty(&lock->waiters);
+}
+
+static int bl_down_read(struct block_lock *lock)
+{
+ int r;
+ struct waiter w;
+
+ spin_lock(&lock->lock);
+ r = __check_holder(lock);
+ if (r) {
+ spin_unlock(&lock->lock);
+ return r;
+ }
+
+ if (__available_for_read(lock)) {
+ lock->count++;
+ __add_holder(lock, current);
+ spin_unlock(&lock->lock);
+ return 0;
+ }
+
+ get_task_struct(current);
+
+ w.task = current;
+ w.wants_write = 0;
+ list_add_tail(&w.list, &lock->waiters);
+ spin_unlock(&lock->lock);
+
+ __wait(&w);
+ put_task_struct(current);
+ return 0;
+}
+
+static int bl_down_read_nonblock(struct block_lock *lock)
+{
+ int r;
+
+ spin_lock(&lock->lock);
+ r = __check_holder(lock);
+ if (r)
+ goto out;
+
+ if (__available_for_read(lock)) {
+ lock->count++;
+ __add_holder(lock, current);
+ r = 0;
+ } else
+ r = -EWOULDBLOCK;
+
+out:
+ spin_unlock(&lock->lock);
+ return r;
+}
+
+static void bl_up_read(struct block_lock *lock)
+{
+ spin_lock(&lock->lock);
+ BUG_ON(lock->count <= 0);
+ __del_holder(lock, current);
+ --lock->count;
+ if (!list_empty(&lock->waiters))
+ __wake_many(lock);
+ spin_unlock(&lock->lock);
+}
+
+static int bl_down_write(struct block_lock *lock)
+{
+ int r;
+ struct waiter w;
+
+ spin_lock(&lock->lock);
+ r = __check_holder(lock);
+ if (r) {
+ spin_unlock(&lock->lock);
+ return r;
+ }
+
+ if (lock->count == 0 && list_empty(&lock->waiters)) {
+ lock->count = -1;
+ __add_holder(lock, current);
+ spin_unlock(&lock->lock);
+ return 0;
+ }
+
+ get_task_struct(current);
+ w.task = current;
+ w.wants_write = 1;
+
+ /*
+ * Writers given priority. We know there's only one mutator in the
+ * system, so ignoring the ordering reversal.
+ */
+ list_add(&w.list, &lock->waiters);
+ spin_unlock(&lock->lock);
+
+ __wait(&w);
+ put_task_struct(current);
+
+ return 0;
+}
+
+static void bl_up_write(struct block_lock *lock)
+{
+ spin_lock(&lock->lock);
+ __del_holder(lock, current);
+ lock->count = 0;
+ if (!list_empty(&lock->waiters))
+ __wake_many(lock);
+ spin_unlock(&lock->lock);
+}
+
+static void report_recursive_bug(dm_block_t b, int r)
+{
+ if (r == -EINVAL)
+ DMERR("recursive acquisition of block %llu requested.",
+ (unsigned long long) b);
+}
+
+/*----------------------------------------------------------------*/
+
+/*
+ * Block manager is currently implemented using dm-bufio. struct
+ * dm_block_manager and struct dm_block map directly onto a couple of
+ * structs in the bufio interface. I want to retain the freedom to move
+ * away from bufio in the future. So these structs are just cast within
+ * this .c file, rather than making it through to the public interface.
+ */
+static struct dm_buffer *to_buffer(struct dm_block *b)
+{
+ return (struct dm_buffer *) b;
+}
+
+dm_block_t dm_block_location(struct dm_block *b)
+{
+ return dm_bufio_get_block_number(to_buffer(b));
+}
+EXPORT_SYMBOL_GPL(dm_block_location);
+
+void *dm_block_data(struct dm_block *b)
+{
+ return dm_bufio_get_block_data(to_buffer(b));
+}
+EXPORT_SYMBOL_GPL(dm_block_data);
+
+struct buffer_aux {
+ struct dm_block_validator *validator;
+ struct block_lock lock;
+ int write_locked;
+};
+
+static void dm_block_manager_alloc_callback(struct dm_buffer *buf)
+{
+ struct buffer_aux *aux = dm_bufio_get_aux_data(buf);
+ aux->validator = NULL;
+ bl_init(&aux->lock);
+}
+
+static void dm_block_manager_write_callback(struct dm_buffer *buf)
+{
+ struct buffer_aux *aux = dm_bufio_get_aux_data(buf);
+ if (aux->validator) {
+ aux->validator->prepare_for_write(aux->validator, (struct dm_block *) buf,
+ dm_bufio_get_block_size(dm_bufio_get_client(buf)));
+ }
+}
+
+/*----------------------------------------------------------------
+ * Public interface
+ *--------------------------------------------------------------*/
+struct dm_block_manager {
+ struct dm_bufio_client *bufio;
+ bool read_only:1;
+};
+
+struct dm_block_manager *dm_block_manager_create(struct block_device *bdev,
+ unsigned block_size,
+ unsigned cache_size,
+ unsigned max_held_per_thread)
+{
+ int r;
+ struct dm_block_manager *bm;
+
+ bm = kmalloc(sizeof(*bm), GFP_KERNEL);
+ if (!bm) {
+ r = -ENOMEM;
+ goto bad;
+ }
+
+ bm->bufio = dm_bufio_client_create(bdev, block_size, max_held_per_thread,
+ sizeof(struct buffer_aux),
+ dm_block_manager_alloc_callback,
+ dm_block_manager_write_callback);
+ if (IS_ERR(bm->bufio)) {
+ r = PTR_ERR(bm->bufio);
+ kfree(bm);
+ goto bad;
+ }
+
+ bm->read_only = false;
+
+ return bm;
+
+bad:
+ return ERR_PTR(r);
+}
+EXPORT_SYMBOL_GPL(dm_block_manager_create);
+
+void dm_block_manager_destroy(struct dm_block_manager *bm)
+{
+ dm_bufio_client_destroy(bm->bufio);
+ kfree(bm);
+}
+EXPORT_SYMBOL_GPL(dm_block_manager_destroy);
+
+unsigned dm_bm_block_size(struct dm_block_manager *bm)
+{
+ return dm_bufio_get_block_size(bm->bufio);
+}
+EXPORT_SYMBOL_GPL(dm_bm_block_size);
+
+dm_block_t dm_bm_nr_blocks(struct dm_block_manager *bm)
+{
+ return dm_bufio_get_device_size(bm->bufio);
+}
+
+static int dm_bm_validate_buffer(struct dm_block_manager *bm,
+ struct dm_buffer *buf,
+ struct buffer_aux *aux,
+ struct dm_block_validator *v)
+{
+ if (unlikely(!aux->validator)) {
+ int r;
+ if (!v)
+ return 0;
+ r = v->check(v, (struct dm_block *) buf, dm_bufio_get_block_size(bm->bufio));
+ if (unlikely(r)) {
+ DMERR_LIMIT("%s validator check failed for block %llu", v->name,
+ (unsigned long long) dm_bufio_get_block_number(buf));
+ return r;
+ }
+ aux->validator = v;
+ } else {
+ if (unlikely(aux->validator != v)) {
+ DMERR_LIMIT("validator mismatch (old=%s vs new=%s) for block %llu",
+ aux->validator->name, v ? v->name : "NULL",
+ (unsigned long long) dm_bufio_get_block_number(buf));
+ return -EINVAL;
+ }
+ }
+
+ return 0;
+}
+int dm_bm_read_lock(struct dm_block_manager *bm, dm_block_t b,
+ struct dm_block_validator *v,
+ struct dm_block **result)
+{
+ struct buffer_aux *aux;
+ void *p;
+ int r;
+
+ p = dm_bufio_read(bm->bufio, b, (struct dm_buffer **) result);
+ if (unlikely(IS_ERR(p)))
+ return PTR_ERR(p);
+
+ aux = dm_bufio_get_aux_data(to_buffer(*result));
+ r = bl_down_read(&aux->lock);
+ if (unlikely(r)) {
+ dm_bufio_release(to_buffer(*result));
+ report_recursive_bug(b, r);
+ return r;
+ }
+
+ aux->write_locked = 0;
+
+ r = dm_bm_validate_buffer(bm, to_buffer(*result), aux, v);
+ if (unlikely(r)) {
+ bl_up_read(&aux->lock);
+ dm_bufio_release(to_buffer(*result));
+ return r;
+ }
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(dm_bm_read_lock);
+
+int dm_bm_write_lock(struct dm_block_manager *bm,
+ dm_block_t b, struct dm_block_validator *v,
+ struct dm_block **result)
+{
+ struct buffer_aux *aux;
+ void *p;
+ int r;
+
+ if (bm->read_only)
+ return -EPERM;
+
+ p = dm_bufio_read(bm->bufio, b, (struct dm_buffer **) result);
+ if (unlikely(IS_ERR(p)))
+ return PTR_ERR(p);
+
+ aux = dm_bufio_get_aux_data(to_buffer(*result));
+ r = bl_down_write(&aux->lock);
+ if (r) {
+ dm_bufio_release(to_buffer(*result));
+ report_recursive_bug(b, r);
+ return r;
+ }
+
+ aux->write_locked = 1;
+
+ r = dm_bm_validate_buffer(bm, to_buffer(*result), aux, v);
+ if (unlikely(r)) {
+ bl_up_write(&aux->lock);
+ dm_bufio_release(to_buffer(*result));
+ return r;
+ }
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(dm_bm_write_lock);
+
+int dm_bm_read_try_lock(struct dm_block_manager *bm,
+ dm_block_t b, struct dm_block_validator *v,
+ struct dm_block **result)
+{
+ struct buffer_aux *aux;
+ void *p;
+ int r;
+
+ p = dm_bufio_get(bm->bufio, b, (struct dm_buffer **) result);
+ if (unlikely(IS_ERR(p)))
+ return PTR_ERR(p);
+ if (unlikely(!p))
+ return -EWOULDBLOCK;
+
+ aux = dm_bufio_get_aux_data(to_buffer(*result));
+ r = bl_down_read_nonblock(&aux->lock);
+ if (r < 0) {
+ dm_bufio_release(to_buffer(*result));
+ report_recursive_bug(b, r);
+ return r;
+ }
+ aux->write_locked = 0;
+
+ r = dm_bm_validate_buffer(bm, to_buffer(*result), aux, v);
+ if (unlikely(r)) {
+ bl_up_read(&aux->lock);
+ dm_bufio_release(to_buffer(*result));
+ return r;
+ }
+
+ return 0;
+}
+
+int dm_bm_write_lock_zero(struct dm_block_manager *bm,
+ dm_block_t b, struct dm_block_validator *v,
+ struct dm_block **result)
+{
+ int r;
+ struct buffer_aux *aux;
+ void *p;
+
+ if (bm->read_only)
+ return -EPERM;
+
+ p = dm_bufio_new(bm->bufio, b, (struct dm_buffer **) result);
+ if (unlikely(IS_ERR(p)))
+ return PTR_ERR(p);
+
+ memset(p, 0, dm_bm_block_size(bm));
+
+ aux = dm_bufio_get_aux_data(to_buffer(*result));
+ r = bl_down_write(&aux->lock);
+ if (r) {
+ dm_bufio_release(to_buffer(*result));
+ return r;
+ }
+
+ aux->write_locked = 1;
+ aux->validator = v;
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(dm_bm_write_lock_zero);
+
+int dm_bm_unlock(struct dm_block *b)
+{
+ struct buffer_aux *aux;
+ aux = dm_bufio_get_aux_data(to_buffer(b));
+
+ if (aux->write_locked) {
+ dm_bufio_mark_buffer_dirty(to_buffer(b));
+ bl_up_write(&aux->lock);
+ } else
+ bl_up_read(&aux->lock);
+
+ dm_bufio_release(to_buffer(b));
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(dm_bm_unlock);
+
+int dm_bm_flush(struct dm_block_manager *bm)
+{
+ if (bm->read_only)
+ return -EPERM;
+
+ return dm_bufio_write_dirty_buffers(bm->bufio);
+}
+EXPORT_SYMBOL_GPL(dm_bm_flush);
+
+void dm_bm_prefetch(struct dm_block_manager *bm, dm_block_t b)
+{
+ dm_bufio_prefetch(bm->bufio, b, 1);
+}
+
+void dm_bm_set_read_only(struct dm_block_manager *bm)
+{
+ bm->read_only = true;
+}
+EXPORT_SYMBOL_GPL(dm_bm_set_read_only);
+
+void dm_bm_set_read_write(struct dm_block_manager *bm)
+{
+ bm->read_only = false;
+}
+EXPORT_SYMBOL_GPL(dm_bm_set_read_write);
+
+u32 dm_bm_checksum(const void *data, size_t len, u32 init_xor)
+{
+ return crc32c(~(u32) 0, data, len) ^ init_xor;
+}
+EXPORT_SYMBOL_GPL(dm_bm_checksum);
+
+/*----------------------------------------------------------------*/
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Joe Thornber <dm-devel@redhat.com>");
+MODULE_DESCRIPTION("Immutable metadata library for dm");
+
+/*----------------------------------------------------------------*/
diff --git a/kernel/drivers/md/persistent-data/dm-block-manager.h b/kernel/drivers/md/persistent-data/dm-block-manager.h
new file mode 100644
index 000000000..1b95dfc17
--- /dev/null
+++ b/kernel/drivers/md/persistent-data/dm-block-manager.h
@@ -0,0 +1,133 @@
+/*
+ * Copyright (C) 2011 Red Hat, Inc.
+ *
+ * This file is released under the GPL.
+ */
+
+#ifndef _LINUX_DM_BLOCK_MANAGER_H
+#define _LINUX_DM_BLOCK_MANAGER_H
+
+#include <linux/types.h>
+#include <linux/blkdev.h>
+
+/*----------------------------------------------------------------*/
+
+/*
+ * Block number.
+ */
+typedef uint64_t dm_block_t;
+struct dm_block;
+
+dm_block_t dm_block_location(struct dm_block *b);
+void *dm_block_data(struct dm_block *b);
+
+/*----------------------------------------------------------------*/
+
+/*
+ * @name should be a unique identifier for the block manager, no longer
+ * than 32 chars.
+ *
+ * @max_held_per_thread should be the maximum number of locks, read or
+ * write, that an individual thread holds at any one time.
+ */
+struct dm_block_manager;
+struct dm_block_manager *dm_block_manager_create(
+ struct block_device *bdev, unsigned block_size,
+ unsigned cache_size, unsigned max_held_per_thread);
+void dm_block_manager_destroy(struct dm_block_manager *bm);
+
+unsigned dm_bm_block_size(struct dm_block_manager *bm);
+dm_block_t dm_bm_nr_blocks(struct dm_block_manager *bm);
+
+/*----------------------------------------------------------------*/
+
+/*
+ * The validator allows the caller to verify newly-read data and modify
+ * the data just before writing, e.g. to calculate checksums. It's
+ * important to be consistent with your use of validators. The only time
+ * you can change validators is if you call dm_bm_write_lock_zero.
+ */
+struct dm_block_validator {
+ const char *name;
+ void (*prepare_for_write)(struct dm_block_validator *v, struct dm_block *b, size_t block_size);
+
+ /*
+ * Return 0 if the checksum is valid or < 0 on error.
+ */
+ int (*check)(struct dm_block_validator *v, struct dm_block *b, size_t block_size);
+};
+
+/*----------------------------------------------------------------*/
+
+/*
+ * You can have multiple concurrent readers or a single writer holding a
+ * block lock.
+ */
+
+/*
+ * dm_bm_lock() locks a block and returns through @result a pointer to
+ * memory that holds a copy of that block. If you have write-locked the
+ * block then any changes you make to memory pointed to by @result will be
+ * written back to the disk sometime after dm_bm_unlock is called.
+ */
+int dm_bm_read_lock(struct dm_block_manager *bm, dm_block_t b,
+ struct dm_block_validator *v,
+ struct dm_block **result);
+
+int dm_bm_write_lock(struct dm_block_manager *bm, dm_block_t b,
+ struct dm_block_validator *v,
+ struct dm_block **result);
+
+/*
+ * The *_try_lock variants return -EWOULDBLOCK if the block isn't
+ * available immediately.
+ */
+int dm_bm_read_try_lock(struct dm_block_manager *bm, dm_block_t b,
+ struct dm_block_validator *v,
+ struct dm_block **result);
+
+/*
+ * Use dm_bm_write_lock_zero() when you know you're going to
+ * overwrite the block completely. It saves a disk read.
+ */
+int dm_bm_write_lock_zero(struct dm_block_manager *bm, dm_block_t b,
+ struct dm_block_validator *v,
+ struct dm_block **result);
+
+int dm_bm_unlock(struct dm_block *b);
+
+/*
+ * It's a common idiom to have a superblock that should be committed last.
+ *
+ * @superblock should be write-locked on entry. It will be unlocked during
+ * this function. All dirty blocks are guaranteed to be written and flushed
+ * before the superblock.
+ *
+ * This method always blocks.
+ */
+int dm_bm_flush(struct dm_block_manager *bm);
+
+/*
+ * Request data is prefetched into the cache.
+ */
+void dm_bm_prefetch(struct dm_block_manager *bm, dm_block_t b);
+
+/*
+ * Switches the bm to a read only mode. Once read-only mode
+ * has been entered the following functions will return -EPERM.
+ *
+ * dm_bm_write_lock
+ * dm_bm_write_lock_zero
+ * dm_bm_flush_and_unlock
+ *
+ * Additionally you should not use dm_bm_unlock_move, however no error will
+ * be returned if you do.
+ */
+void dm_bm_set_read_only(struct dm_block_manager *bm);
+void dm_bm_set_read_write(struct dm_block_manager *bm);
+
+u32 dm_bm_checksum(const void *data, size_t len, u32 init_xor);
+
+/*----------------------------------------------------------------*/
+
+#endif /* _LINUX_DM_BLOCK_MANAGER_H */
diff --git a/kernel/drivers/md/persistent-data/dm-btree-internal.h b/kernel/drivers/md/persistent-data/dm-btree-internal.h
new file mode 100644
index 000000000..bf2b80d5c
--- /dev/null
+++ b/kernel/drivers/md/persistent-data/dm-btree-internal.h
@@ -0,0 +1,141 @@
+/*
+ * Copyright (C) 2011 Red Hat, Inc.
+ *
+ * This file is released under the GPL.
+ */
+
+#ifndef DM_BTREE_INTERNAL_H
+#define DM_BTREE_INTERNAL_H
+
+#include "dm-btree.h"
+
+/*----------------------------------------------------------------*/
+
+/*
+ * We'll need 2 accessor functions for n->csum and n->blocknr
+ * to support dm-btree-spine.c in that case.
+ */
+
+enum node_flags {
+ INTERNAL_NODE = 1,
+ LEAF_NODE = 1 << 1
+};
+
+/*
+ * Every btree node begins with this structure. Make sure it's a multiple
+ * of 8-bytes in size, otherwise the 64bit keys will be mis-aligned.
+ */
+struct node_header {
+ __le32 csum;
+ __le32 flags;
+ __le64 blocknr; /* Block this node is supposed to live in. */
+
+ __le32 nr_entries;
+ __le32 max_entries;
+ __le32 value_size;
+ __le32 padding;
+} __packed;
+
+struct btree_node {
+ struct node_header header;
+ __le64 keys[0];
+} __packed;
+
+
+/*
+ * Locks a block using the btree node validator.
+ */
+int bn_read_lock(struct dm_btree_info *info, dm_block_t b,
+ struct dm_block **result);
+
+void inc_children(struct dm_transaction_manager *tm, struct btree_node *n,
+ struct dm_btree_value_type *vt);
+
+int new_block(struct dm_btree_info *info, struct dm_block **result);
+int unlock_block(struct dm_btree_info *info, struct dm_block *b);
+
+/*
+ * Spines keep track of the rolling locks. There are 2 variants, read-only
+ * and one that uses shadowing. These are separate structs to allow the
+ * type checker to spot misuse, for example accidentally calling read_lock
+ * on a shadow spine.
+ */
+struct ro_spine {
+ struct dm_btree_info *info;
+
+ int count;
+ struct dm_block *nodes[2];
+};
+
+void init_ro_spine(struct ro_spine *s, struct dm_btree_info *info);
+int exit_ro_spine(struct ro_spine *s);
+int ro_step(struct ro_spine *s, dm_block_t new_child);
+void ro_pop(struct ro_spine *s);
+struct btree_node *ro_node(struct ro_spine *s);
+
+struct shadow_spine {
+ struct dm_btree_info *info;
+
+ int count;
+ struct dm_block *nodes[2];
+
+ dm_block_t root;
+};
+
+void init_shadow_spine(struct shadow_spine *s, struct dm_btree_info *info);
+int exit_shadow_spine(struct shadow_spine *s);
+
+int shadow_step(struct shadow_spine *s, dm_block_t b,
+ struct dm_btree_value_type *vt);
+
+/*
+ * The spine must have at least one entry before calling this.
+ */
+struct dm_block *shadow_current(struct shadow_spine *s);
+
+/*
+ * The spine must have at least two entries before calling this.
+ */
+struct dm_block *shadow_parent(struct shadow_spine *s);
+
+int shadow_has_parent(struct shadow_spine *s);
+
+int shadow_root(struct shadow_spine *s);
+
+/*
+ * Some inlines.
+ */
+static inline __le64 *key_ptr(struct btree_node *n, uint32_t index)
+{
+ return n->keys + index;
+}
+
+static inline void *value_base(struct btree_node *n)
+{
+ return &n->keys[le32_to_cpu(n->header.max_entries)];
+}
+
+static inline void *value_ptr(struct btree_node *n, uint32_t index)
+{
+ uint32_t value_size = le32_to_cpu(n->header.value_size);
+ return value_base(n) + (value_size * index);
+}
+
+/*
+ * Assumes the values are suitably-aligned and converts to core format.
+ */
+static inline uint64_t value64(struct btree_node *n, uint32_t index)
+{
+ __le64 *values_le = value_base(n);
+
+ return le64_to_cpu(values_le[index]);
+}
+
+/*
+ * Searching for a key within a single node.
+ */
+int lower_bound(struct btree_node *n, uint64_t key);
+
+extern struct dm_block_validator btree_node_validator;
+
+#endif /* DM_BTREE_INTERNAL_H */
diff --git a/kernel/drivers/md/persistent-data/dm-btree-remove.c b/kernel/drivers/md/persistent-data/dm-btree-remove.c
new file mode 100644
index 000000000..b88757cd0
--- /dev/null
+++ b/kernel/drivers/md/persistent-data/dm-btree-remove.c
@@ -0,0 +1,592 @@
+/*
+ * Copyright (C) 2011 Red Hat, Inc.
+ *
+ * This file is released under the GPL.
+ */
+
+#include "dm-btree.h"
+#include "dm-btree-internal.h"
+#include "dm-transaction-manager.h"
+
+#include <linux/export.h>
+
+/*
+ * Removing an entry from a btree
+ * ==============================
+ *
+ * A very important constraint for our btree is that no node, except the
+ * root, may have fewer than a certain number of entries.
+ * (MIN_ENTRIES <= nr_entries <= MAX_ENTRIES).
+ *
+ * Ensuring this is complicated by the way we want to only ever hold the
+ * locks on 2 nodes concurrently, and only change nodes in a top to bottom
+ * fashion.
+ *
+ * Each node may have a left or right sibling. When decending the spine,
+ * if a node contains only MIN_ENTRIES then we try and increase this to at
+ * least MIN_ENTRIES + 1. We do this in the following ways:
+ *
+ * [A] No siblings => this can only happen if the node is the root, in which
+ * case we copy the childs contents over the root.
+ *
+ * [B] No left sibling
+ * ==> rebalance(node, right sibling)
+ *
+ * [C] No right sibling
+ * ==> rebalance(left sibling, node)
+ *
+ * [D] Both siblings, total_entries(left, node, right) <= DEL_THRESHOLD
+ * ==> delete node adding it's contents to left and right
+ *
+ * [E] Both siblings, total_entries(left, node, right) > DEL_THRESHOLD
+ * ==> rebalance(left, node, right)
+ *
+ * After these operations it's possible that the our original node no
+ * longer contains the desired sub tree. For this reason this rebalancing
+ * is performed on the children of the current node. This also avoids
+ * having a special case for the root.
+ *
+ * Once this rebalancing has occurred we can then step into the child node
+ * for internal nodes. Or delete the entry for leaf nodes.
+ */
+
+/*
+ * Some little utilities for moving node data around.
+ */
+static void node_shift(struct btree_node *n, int shift)
+{
+ uint32_t nr_entries = le32_to_cpu(n->header.nr_entries);
+ uint32_t value_size = le32_to_cpu(n->header.value_size);
+
+ if (shift < 0) {
+ shift = -shift;
+ BUG_ON(shift > nr_entries);
+ BUG_ON((void *) key_ptr(n, shift) >= value_ptr(n, shift));
+ memmove(key_ptr(n, 0),
+ key_ptr(n, shift),
+ (nr_entries - shift) * sizeof(__le64));
+ memmove(value_ptr(n, 0),
+ value_ptr(n, shift),
+ (nr_entries - shift) * value_size);
+ } else {
+ BUG_ON(nr_entries + shift > le32_to_cpu(n->header.max_entries));
+ memmove(key_ptr(n, shift),
+ key_ptr(n, 0),
+ nr_entries * sizeof(__le64));
+ memmove(value_ptr(n, shift),
+ value_ptr(n, 0),
+ nr_entries * value_size);
+ }
+}
+
+static void node_copy(struct btree_node *left, struct btree_node *right, int shift)
+{
+ uint32_t nr_left = le32_to_cpu(left->header.nr_entries);
+ uint32_t value_size = le32_to_cpu(left->header.value_size);
+ BUG_ON(value_size != le32_to_cpu(right->header.value_size));
+
+ if (shift < 0) {
+ shift = -shift;
+ BUG_ON(nr_left + shift > le32_to_cpu(left->header.max_entries));
+ memcpy(key_ptr(left, nr_left),
+ key_ptr(right, 0),
+ shift * sizeof(__le64));
+ memcpy(value_ptr(left, nr_left),
+ value_ptr(right, 0),
+ shift * value_size);
+ } else {
+ BUG_ON(shift > le32_to_cpu(right->header.max_entries));
+ memcpy(key_ptr(right, 0),
+ key_ptr(left, nr_left - shift),
+ shift * sizeof(__le64));
+ memcpy(value_ptr(right, 0),
+ value_ptr(left, nr_left - shift),
+ shift * value_size);
+ }
+}
+
+/*
+ * Delete a specific entry from a leaf node.
+ */
+static void delete_at(struct btree_node *n, unsigned index)
+{
+ unsigned nr_entries = le32_to_cpu(n->header.nr_entries);
+ unsigned nr_to_copy = nr_entries - (index + 1);
+ uint32_t value_size = le32_to_cpu(n->header.value_size);
+ BUG_ON(index >= nr_entries);
+
+ if (nr_to_copy) {
+ memmove(key_ptr(n, index),
+ key_ptr(n, index + 1),
+ nr_to_copy * sizeof(__le64));
+
+ memmove(value_ptr(n, index),
+ value_ptr(n, index + 1),
+ nr_to_copy * value_size);
+ }
+
+ n->header.nr_entries = cpu_to_le32(nr_entries - 1);
+}
+
+static unsigned merge_threshold(struct btree_node *n)
+{
+ return le32_to_cpu(n->header.max_entries) / 3;
+}
+
+struct child {
+ unsigned index;
+ struct dm_block *block;
+ struct btree_node *n;
+};
+
+static int init_child(struct dm_btree_info *info, struct dm_btree_value_type *vt,
+ struct btree_node *parent,
+ unsigned index, struct child *result)
+{
+ int r, inc;
+ dm_block_t root;
+
+ result->index = index;
+ root = value64(parent, index);
+
+ r = dm_tm_shadow_block(info->tm, root, &btree_node_validator,
+ &result->block, &inc);
+ if (r)
+ return r;
+
+ result->n = dm_block_data(result->block);
+
+ if (inc)
+ inc_children(info->tm, result->n, vt);
+
+ *((__le64 *) value_ptr(parent, index)) =
+ cpu_to_le64(dm_block_location(result->block));
+
+ return 0;
+}
+
+static int exit_child(struct dm_btree_info *info, struct child *c)
+{
+ return dm_tm_unlock(info->tm, c->block);
+}
+
+static void shift(struct btree_node *left, struct btree_node *right, int count)
+{
+ uint32_t nr_left = le32_to_cpu(left->header.nr_entries);
+ uint32_t nr_right = le32_to_cpu(right->header.nr_entries);
+ uint32_t max_entries = le32_to_cpu(left->header.max_entries);
+ uint32_t r_max_entries = le32_to_cpu(right->header.max_entries);
+
+ BUG_ON(max_entries != r_max_entries);
+ BUG_ON(nr_left - count > max_entries);
+ BUG_ON(nr_right + count > max_entries);
+
+ if (!count)
+ return;
+
+ if (count > 0) {
+ node_shift(right, count);
+ node_copy(left, right, count);
+ } else {
+ node_copy(left, right, count);
+ node_shift(right, count);
+ }
+
+ left->header.nr_entries = cpu_to_le32(nr_left - count);
+ right->header.nr_entries = cpu_to_le32(nr_right + count);
+}
+
+static void __rebalance2(struct dm_btree_info *info, struct btree_node *parent,
+ struct child *l, struct child *r)
+{
+ struct btree_node *left = l->n;
+ struct btree_node *right = r->n;
+ uint32_t nr_left = le32_to_cpu(left->header.nr_entries);
+ uint32_t nr_right = le32_to_cpu(right->header.nr_entries);
+ unsigned threshold = 2 * merge_threshold(left) + 1;
+
+ if (nr_left + nr_right < threshold) {
+ /*
+ * Merge
+ */
+ node_copy(left, right, -nr_right);
+ left->header.nr_entries = cpu_to_le32(nr_left + nr_right);
+ delete_at(parent, r->index);
+
+ /*
+ * We need to decrement the right block, but not it's
+ * children, since they're still referenced by left.
+ */
+ dm_tm_dec(info->tm, dm_block_location(r->block));
+ } else {
+ /*
+ * Rebalance.
+ */
+ unsigned target_left = (nr_left + nr_right) / 2;
+ shift(left, right, nr_left - target_left);
+ *key_ptr(parent, r->index) = right->keys[0];
+ }
+}
+
+static int rebalance2(struct shadow_spine *s, struct dm_btree_info *info,
+ struct dm_btree_value_type *vt, unsigned left_index)
+{
+ int r;
+ struct btree_node *parent;
+ struct child left, right;
+
+ parent = dm_block_data(shadow_current(s));
+
+ r = init_child(info, vt, parent, left_index, &left);
+ if (r)
+ return r;
+
+ r = init_child(info, vt, parent, left_index + 1, &right);
+ if (r) {
+ exit_child(info, &left);
+ return r;
+ }
+
+ __rebalance2(info, parent, &left, &right);
+
+ r = exit_child(info, &left);
+ if (r) {
+ exit_child(info, &right);
+ return r;
+ }
+
+ return exit_child(info, &right);
+}
+
+/*
+ * We dump as many entries from center as possible into left, then the rest
+ * in right, then rebalance2. This wastes some cpu, but I want something
+ * simple atm.
+ */
+static void delete_center_node(struct dm_btree_info *info, struct btree_node *parent,
+ struct child *l, struct child *c, struct child *r,
+ struct btree_node *left, struct btree_node *center, struct btree_node *right,
+ uint32_t nr_left, uint32_t nr_center, uint32_t nr_right)
+{
+ uint32_t max_entries = le32_to_cpu(left->header.max_entries);
+ unsigned shift = min(max_entries - nr_left, nr_center);
+
+ BUG_ON(nr_left + shift > max_entries);
+ node_copy(left, center, -shift);
+ left->header.nr_entries = cpu_to_le32(nr_left + shift);
+
+ if (shift != nr_center) {
+ shift = nr_center - shift;
+ BUG_ON((nr_right + shift) > max_entries);
+ node_shift(right, shift);
+ node_copy(center, right, shift);
+ right->header.nr_entries = cpu_to_le32(nr_right + shift);
+ }
+ *key_ptr(parent, r->index) = right->keys[0];
+
+ delete_at(parent, c->index);
+ r->index--;
+
+ dm_tm_dec(info->tm, dm_block_location(c->block));
+ __rebalance2(info, parent, l, r);
+}
+
+/*
+ * Redistributes entries among 3 sibling nodes.
+ */
+static void redistribute3(struct dm_btree_info *info, struct btree_node *parent,
+ struct child *l, struct child *c, struct child *r,
+ struct btree_node *left, struct btree_node *center, struct btree_node *right,
+ uint32_t nr_left, uint32_t nr_center, uint32_t nr_right)
+{
+ int s;
+ uint32_t max_entries = le32_to_cpu(left->header.max_entries);
+ unsigned target = (nr_left + nr_center + nr_right) / 3;
+ BUG_ON(target > max_entries);
+
+ if (nr_left < nr_right) {
+ s = nr_left - target;
+
+ if (s < 0 && nr_center < -s) {
+ /* not enough in central node */
+ shift(left, center, nr_center);
+ s = nr_center - target;
+ shift(left, right, s);
+ nr_right += s;
+ } else
+ shift(left, center, s);
+
+ shift(center, right, target - nr_right);
+
+ } else {
+ s = target - nr_right;
+ if (s > 0 && nr_center < s) {
+ /* not enough in central node */
+ shift(center, right, nr_center);
+ s = target - nr_center;
+ shift(left, right, s);
+ nr_left -= s;
+ } else
+ shift(center, right, s);
+
+ shift(left, center, nr_left - target);
+ }
+
+ *key_ptr(parent, c->index) = center->keys[0];
+ *key_ptr(parent, r->index) = right->keys[0];
+}
+
+static void __rebalance3(struct dm_btree_info *info, struct btree_node *parent,
+ struct child *l, struct child *c, struct child *r)
+{
+ struct btree_node *left = l->n;
+ struct btree_node *center = c->n;
+ struct btree_node *right = r->n;
+
+ uint32_t nr_left = le32_to_cpu(left->header.nr_entries);
+ uint32_t nr_center = le32_to_cpu(center->header.nr_entries);
+ uint32_t nr_right = le32_to_cpu(right->header.nr_entries);
+
+ unsigned threshold = merge_threshold(left) * 4 + 1;
+
+ BUG_ON(left->header.max_entries != center->header.max_entries);
+ BUG_ON(center->header.max_entries != right->header.max_entries);
+
+ if ((nr_left + nr_center + nr_right) < threshold)
+ delete_center_node(info, parent, l, c, r, left, center, right,
+ nr_left, nr_center, nr_right);
+ else
+ redistribute3(info, parent, l, c, r, left, center, right,
+ nr_left, nr_center, nr_right);
+}
+
+static int rebalance3(struct shadow_spine *s, struct dm_btree_info *info,
+ struct dm_btree_value_type *vt, unsigned left_index)
+{
+ int r;
+ struct btree_node *parent = dm_block_data(shadow_current(s));
+ struct child left, center, right;
+
+ /*
+ * FIXME: fill out an array?
+ */
+ r = init_child(info, vt, parent, left_index, &left);
+ if (r)
+ return r;
+
+ r = init_child(info, vt, parent, left_index + 1, &center);
+ if (r) {
+ exit_child(info, &left);
+ return r;
+ }
+
+ r = init_child(info, vt, parent, left_index + 2, &right);
+ if (r) {
+ exit_child(info, &left);
+ exit_child(info, &center);
+ return r;
+ }
+
+ __rebalance3(info, parent, &left, &center, &right);
+
+ r = exit_child(info, &left);
+ if (r) {
+ exit_child(info, &center);
+ exit_child(info, &right);
+ return r;
+ }
+
+ r = exit_child(info, &center);
+ if (r) {
+ exit_child(info, &right);
+ return r;
+ }
+
+ r = exit_child(info, &right);
+ if (r)
+ return r;
+
+ return 0;
+}
+
+static int get_nr_entries(struct dm_transaction_manager *tm,
+ dm_block_t b, uint32_t *result)
+{
+ int r;
+ struct dm_block *block;
+ struct btree_node *n;
+
+ r = dm_tm_read_lock(tm, b, &btree_node_validator, &block);
+ if (r)
+ return r;
+
+ n = dm_block_data(block);
+ *result = le32_to_cpu(n->header.nr_entries);
+
+ return dm_tm_unlock(tm, block);
+}
+
+static int rebalance_children(struct shadow_spine *s,
+ struct dm_btree_info *info,
+ struct dm_btree_value_type *vt, uint64_t key)
+{
+ int i, r, has_left_sibling, has_right_sibling;
+ uint32_t child_entries;
+ struct btree_node *n;
+
+ n = dm_block_data(shadow_current(s));
+
+ if (le32_to_cpu(n->header.nr_entries) == 1) {
+ struct dm_block *child;
+ dm_block_t b = value64(n, 0);
+
+ r = dm_tm_read_lock(info->tm, b, &btree_node_validator, &child);
+ if (r)
+ return r;
+
+ memcpy(n, dm_block_data(child),
+ dm_bm_block_size(dm_tm_get_bm(info->tm)));
+ r = dm_tm_unlock(info->tm, child);
+ if (r)
+ return r;
+
+ dm_tm_dec(info->tm, dm_block_location(child));
+ return 0;
+ }
+
+ i = lower_bound(n, key);
+ if (i < 0)
+ return -ENODATA;
+
+ r = get_nr_entries(info->tm, value64(n, i), &child_entries);
+ if (r)
+ return r;
+
+ has_left_sibling = i > 0;
+ has_right_sibling = i < (le32_to_cpu(n->header.nr_entries) - 1);
+
+ if (!has_left_sibling)
+ r = rebalance2(s, info, vt, i);
+
+ else if (!has_right_sibling)
+ r = rebalance2(s, info, vt, i - 1);
+
+ else
+ r = rebalance3(s, info, vt, i - 1);
+
+ return r;
+}
+
+static int do_leaf(struct btree_node *n, uint64_t key, unsigned *index)
+{
+ int i = lower_bound(n, key);
+
+ if ((i < 0) ||
+ (i >= le32_to_cpu(n->header.nr_entries)) ||
+ (le64_to_cpu(n->keys[i]) != key))
+ return -ENODATA;
+
+ *index = i;
+
+ return 0;
+}
+
+/*
+ * Prepares for removal from one level of the hierarchy. The caller must
+ * call delete_at() to remove the entry at index.
+ */
+static int remove_raw(struct shadow_spine *s, struct dm_btree_info *info,
+ struct dm_btree_value_type *vt, dm_block_t root,
+ uint64_t key, unsigned *index)
+{
+ int i = *index, r;
+ struct btree_node *n;
+
+ for (;;) {
+ r = shadow_step(s, root, vt);
+ if (r < 0)
+ break;
+
+ /*
+ * We have to patch up the parent node, ugly, but I don't
+ * see a way to do this automatically as part of the spine
+ * op.
+ */
+ if (shadow_has_parent(s)) {
+ __le64 location = cpu_to_le64(dm_block_location(shadow_current(s)));
+ memcpy(value_ptr(dm_block_data(shadow_parent(s)), i),
+ &location, sizeof(__le64));
+ }
+
+ n = dm_block_data(shadow_current(s));
+
+ if (le32_to_cpu(n->header.flags) & LEAF_NODE)
+ return do_leaf(n, key, index);
+
+ r = rebalance_children(s, info, vt, key);
+ if (r)
+ break;
+
+ n = dm_block_data(shadow_current(s));
+ if (le32_to_cpu(n->header.flags) & LEAF_NODE)
+ return do_leaf(n, key, index);
+
+ i = lower_bound(n, key);
+
+ /*
+ * We know the key is present, or else
+ * rebalance_children would have returned
+ * -ENODATA
+ */
+ root = value64(n, i);
+ }
+
+ return r;
+}
+
+static struct dm_btree_value_type le64_type = {
+ .context = NULL,
+ .size = sizeof(__le64),
+ .inc = NULL,
+ .dec = NULL,
+ .equal = NULL
+};
+
+int dm_btree_remove(struct dm_btree_info *info, dm_block_t root,
+ uint64_t *keys, dm_block_t *new_root)
+{
+ unsigned level, last_level = info->levels - 1;
+ int index = 0, r = 0;
+ struct shadow_spine spine;
+ struct btree_node *n;
+
+ init_shadow_spine(&spine, info);
+ for (level = 0; level < info->levels; level++) {
+ r = remove_raw(&spine, info,
+ (level == last_level ?
+ &info->value_type : &le64_type),
+ root, keys[level], (unsigned *)&index);
+ if (r < 0)
+ break;
+
+ n = dm_block_data(shadow_current(&spine));
+ if (level != last_level) {
+ root = value64(n, index);
+ continue;
+ }
+
+ BUG_ON(index < 0 || index >= le32_to_cpu(n->header.nr_entries));
+
+ if (info->value_type.dec)
+ info->value_type.dec(info->value_type.context,
+ value_ptr(n, index));
+
+ delete_at(n, index);
+ }
+
+ *new_root = shadow_root(&spine);
+ exit_shadow_spine(&spine);
+
+ return r;
+}
+EXPORT_SYMBOL_GPL(dm_btree_remove);
diff --git a/kernel/drivers/md/persistent-data/dm-btree-spine.c b/kernel/drivers/md/persistent-data/dm-btree-spine.c
new file mode 100644
index 000000000..1b5e13ec7
--- /dev/null
+++ b/kernel/drivers/md/persistent-data/dm-btree-spine.c
@@ -0,0 +1,251 @@
+/*
+ * Copyright (C) 2011 Red Hat, Inc.
+ *
+ * This file is released under the GPL.
+ */
+
+#include "dm-btree-internal.h"
+#include "dm-transaction-manager.h"
+
+#include <linux/device-mapper.h>
+
+#define DM_MSG_PREFIX "btree spine"
+
+/*----------------------------------------------------------------*/
+
+#define BTREE_CSUM_XOR 121107
+
+static int node_check(struct dm_block_validator *v,
+ struct dm_block *b,
+ size_t block_size);
+
+static void node_prepare_for_write(struct dm_block_validator *v,
+ struct dm_block *b,
+ size_t block_size)
+{
+ struct btree_node *n = dm_block_data(b);
+ struct node_header *h = &n->header;
+
+ h->blocknr = cpu_to_le64(dm_block_location(b));
+ h->csum = cpu_to_le32(dm_bm_checksum(&h->flags,
+ block_size - sizeof(__le32),
+ BTREE_CSUM_XOR));
+
+ BUG_ON(node_check(v, b, 4096));
+}
+
+static int node_check(struct dm_block_validator *v,
+ struct dm_block *b,
+ size_t block_size)
+{
+ struct btree_node *n = dm_block_data(b);
+ struct node_header *h = &n->header;
+ size_t value_size;
+ __le32 csum_disk;
+ uint32_t flags;
+
+ if (dm_block_location(b) != le64_to_cpu(h->blocknr)) {
+ DMERR_LIMIT("node_check failed: blocknr %llu != wanted %llu",
+ le64_to_cpu(h->blocknr), dm_block_location(b));
+ return -ENOTBLK;
+ }
+
+ csum_disk = cpu_to_le32(dm_bm_checksum(&h->flags,
+ block_size - sizeof(__le32),
+ BTREE_CSUM_XOR));
+ if (csum_disk != h->csum) {
+ DMERR_LIMIT("node_check failed: csum %u != wanted %u",
+ le32_to_cpu(csum_disk), le32_to_cpu(h->csum));
+ return -EILSEQ;
+ }
+
+ value_size = le32_to_cpu(h->value_size);
+
+ if (sizeof(struct node_header) +
+ (sizeof(__le64) + value_size) * le32_to_cpu(h->max_entries) > block_size) {
+ DMERR_LIMIT("node_check failed: max_entries too large");
+ return -EILSEQ;
+ }
+
+ if (le32_to_cpu(h->nr_entries) > le32_to_cpu(h->max_entries)) {
+ DMERR_LIMIT("node_check failed: too many entries");
+ return -EILSEQ;
+ }
+
+ /*
+ * The node must be either INTERNAL or LEAF.
+ */
+ flags = le32_to_cpu(h->flags);
+ if (!(flags & INTERNAL_NODE) && !(flags & LEAF_NODE)) {
+ DMERR_LIMIT("node_check failed: node is neither INTERNAL or LEAF");
+ return -EILSEQ;
+ }
+
+ return 0;
+}
+
+struct dm_block_validator btree_node_validator = {
+ .name = "btree_node",
+ .prepare_for_write = node_prepare_for_write,
+ .check = node_check
+};
+
+/*----------------------------------------------------------------*/
+
+int bn_read_lock(struct dm_btree_info *info, dm_block_t b,
+ struct dm_block **result)
+{
+ return dm_tm_read_lock(info->tm, b, &btree_node_validator, result);
+}
+
+static int bn_shadow(struct dm_btree_info *info, dm_block_t orig,
+ struct dm_btree_value_type *vt,
+ struct dm_block **result)
+{
+ int r, inc;
+
+ r = dm_tm_shadow_block(info->tm, orig, &btree_node_validator,
+ result, &inc);
+ if (!r && inc)
+ inc_children(info->tm, dm_block_data(*result), vt);
+
+ return r;
+}
+
+int new_block(struct dm_btree_info *info, struct dm_block **result)
+{
+ return dm_tm_new_block(info->tm, &btree_node_validator, result);
+}
+
+int unlock_block(struct dm_btree_info *info, struct dm_block *b)
+{
+ return dm_tm_unlock(info->tm, b);
+}
+
+/*----------------------------------------------------------------*/
+
+void init_ro_spine(struct ro_spine *s, struct dm_btree_info *info)
+{
+ s->info = info;
+ s->count = 0;
+ s->nodes[0] = NULL;
+ s->nodes[1] = NULL;
+}
+
+int exit_ro_spine(struct ro_spine *s)
+{
+ int r = 0, i;
+
+ for (i = 0; i < s->count; i++) {
+ int r2 = unlock_block(s->info, s->nodes[i]);
+ if (r2 < 0)
+ r = r2;
+ }
+
+ return r;
+}
+
+int ro_step(struct ro_spine *s, dm_block_t new_child)
+{
+ int r;
+
+ if (s->count == 2) {
+ r = unlock_block(s->info, s->nodes[0]);
+ if (r < 0)
+ return r;
+ s->nodes[0] = s->nodes[1];
+ s->count--;
+ }
+
+ r = bn_read_lock(s->info, new_child, s->nodes + s->count);
+ if (!r)
+ s->count++;
+
+ return r;
+}
+
+void ro_pop(struct ro_spine *s)
+{
+ BUG_ON(!s->count);
+ --s->count;
+ unlock_block(s->info, s->nodes[s->count]);
+}
+
+struct btree_node *ro_node(struct ro_spine *s)
+{
+ struct dm_block *block;
+
+ BUG_ON(!s->count);
+ block = s->nodes[s->count - 1];
+
+ return dm_block_data(block);
+}
+
+/*----------------------------------------------------------------*/
+
+void init_shadow_spine(struct shadow_spine *s, struct dm_btree_info *info)
+{
+ s->info = info;
+ s->count = 0;
+}
+
+int exit_shadow_spine(struct shadow_spine *s)
+{
+ int r = 0, i;
+
+ for (i = 0; i < s->count; i++) {
+ int r2 = unlock_block(s->info, s->nodes[i]);
+ if (r2 < 0)
+ r = r2;
+ }
+
+ return r;
+}
+
+int shadow_step(struct shadow_spine *s, dm_block_t b,
+ struct dm_btree_value_type *vt)
+{
+ int r;
+
+ if (s->count == 2) {
+ r = unlock_block(s->info, s->nodes[0]);
+ if (r < 0)
+ return r;
+ s->nodes[0] = s->nodes[1];
+ s->count--;
+ }
+
+ r = bn_shadow(s->info, b, vt, s->nodes + s->count);
+ if (!r) {
+ if (!s->count)
+ s->root = dm_block_location(s->nodes[0]);
+
+ s->count++;
+ }
+
+ return r;
+}
+
+struct dm_block *shadow_current(struct shadow_spine *s)
+{
+ BUG_ON(!s->count);
+
+ return s->nodes[s->count - 1];
+}
+
+struct dm_block *shadow_parent(struct shadow_spine *s)
+{
+ BUG_ON(s->count != 2);
+
+ return s->count == 2 ? s->nodes[0] : NULL;
+}
+
+int shadow_has_parent(struct shadow_spine *s)
+{
+ return s->count >= 2;
+}
+
+int shadow_root(struct shadow_spine *s)
+{
+ return s->root;
+}
diff --git a/kernel/drivers/md/persistent-data/dm-btree.c b/kernel/drivers/md/persistent-data/dm-btree.c
new file mode 100644
index 000000000..200ac12a1
--- /dev/null
+++ b/kernel/drivers/md/persistent-data/dm-btree.c
@@ -0,0 +1,892 @@
+/*
+ * Copyright (C) 2011 Red Hat, Inc.
+ *
+ * This file is released under the GPL.
+ */
+
+#include "dm-btree-internal.h"
+#include "dm-space-map.h"
+#include "dm-transaction-manager.h"
+
+#include <linux/export.h>
+#include <linux/device-mapper.h>
+
+#define DM_MSG_PREFIX "btree"
+
+/*----------------------------------------------------------------
+ * Array manipulation
+ *--------------------------------------------------------------*/
+static void memcpy_disk(void *dest, const void *src, size_t len)
+ __dm_written_to_disk(src)
+{
+ memcpy(dest, src, len);
+ __dm_unbless_for_disk(src);
+}
+
+static void array_insert(void *base, size_t elt_size, unsigned nr_elts,
+ unsigned index, void *elt)
+ __dm_written_to_disk(elt)
+{
+ if (index < nr_elts)
+ memmove(base + (elt_size * (index + 1)),
+ base + (elt_size * index),
+ (nr_elts - index) * elt_size);
+
+ memcpy_disk(base + (elt_size * index), elt, elt_size);
+}
+
+/*----------------------------------------------------------------*/
+
+/* makes the assumption that no two keys are the same. */
+static int bsearch(struct btree_node *n, uint64_t key, int want_hi)
+{
+ int lo = -1, hi = le32_to_cpu(n->header.nr_entries);
+
+ while (hi - lo > 1) {
+ int mid = lo + ((hi - lo) / 2);
+ uint64_t mid_key = le64_to_cpu(n->keys[mid]);
+
+ if (mid_key == key)
+ return mid;
+
+ if (mid_key < key)
+ lo = mid;
+ else
+ hi = mid;
+ }
+
+ return want_hi ? hi : lo;
+}
+
+int lower_bound(struct btree_node *n, uint64_t key)
+{
+ return bsearch(n, key, 0);
+}
+
+void inc_children(struct dm_transaction_manager *tm, struct btree_node *n,
+ struct dm_btree_value_type *vt)
+{
+ unsigned i;
+ uint32_t nr_entries = le32_to_cpu(n->header.nr_entries);
+
+ if (le32_to_cpu(n->header.flags) & INTERNAL_NODE)
+ for (i = 0; i < nr_entries; i++)
+ dm_tm_inc(tm, value64(n, i));
+ else if (vt->inc)
+ for (i = 0; i < nr_entries; i++)
+ vt->inc(vt->context, value_ptr(n, i));
+}
+
+static int insert_at(size_t value_size, struct btree_node *node, unsigned index,
+ uint64_t key, void *value)
+ __dm_written_to_disk(value)
+{
+ uint32_t nr_entries = le32_to_cpu(node->header.nr_entries);
+ __le64 key_le = cpu_to_le64(key);
+
+ if (index > nr_entries ||
+ index >= le32_to_cpu(node->header.max_entries)) {
+ DMERR("too many entries in btree node for insert");
+ __dm_unbless_for_disk(value);
+ return -ENOMEM;
+ }
+
+ __dm_bless_for_disk(&key_le);
+
+ array_insert(node->keys, sizeof(*node->keys), nr_entries, index, &key_le);
+ array_insert(value_base(node), value_size, nr_entries, index, value);
+ node->header.nr_entries = cpu_to_le32(nr_entries + 1);
+
+ return 0;
+}
+
+/*----------------------------------------------------------------*/
+
+/*
+ * We want 3n entries (for some n). This works more nicely for repeated
+ * insert remove loops than (2n + 1).
+ */
+static uint32_t calc_max_entries(size_t value_size, size_t block_size)
+{
+ uint32_t total, n;
+ size_t elt_size = sizeof(uint64_t) + value_size; /* key + value */
+
+ block_size -= sizeof(struct node_header);
+ total = block_size / elt_size;
+ n = total / 3; /* rounds down */
+
+ return 3 * n;
+}
+
+int dm_btree_empty(struct dm_btree_info *info, dm_block_t *root)
+{
+ int r;
+ struct dm_block *b;
+ struct btree_node *n;
+ size_t block_size;
+ uint32_t max_entries;
+
+ r = new_block(info, &b);
+ if (r < 0)
+ return r;
+
+ block_size = dm_bm_block_size(dm_tm_get_bm(info->tm));
+ max_entries = calc_max_entries(info->value_type.size, block_size);
+
+ n = dm_block_data(b);
+ memset(n, 0, block_size);
+ n->header.flags = cpu_to_le32(LEAF_NODE);
+ n->header.nr_entries = cpu_to_le32(0);
+ n->header.max_entries = cpu_to_le32(max_entries);
+ n->header.value_size = cpu_to_le32(info->value_type.size);
+
+ *root = dm_block_location(b);
+ return unlock_block(info, b);
+}
+EXPORT_SYMBOL_GPL(dm_btree_empty);
+
+/*----------------------------------------------------------------*/
+
+/*
+ * Deletion uses a recursive algorithm, since we have limited stack space
+ * we explicitly manage our own stack on the heap.
+ */
+#define MAX_SPINE_DEPTH 64
+struct frame {
+ struct dm_block *b;
+ struct btree_node *n;
+ unsigned level;
+ unsigned nr_children;
+ unsigned current_child;
+};
+
+struct del_stack {
+ struct dm_btree_info *info;
+ struct dm_transaction_manager *tm;
+ int top;
+ struct frame spine[MAX_SPINE_DEPTH];
+};
+
+static int top_frame(struct del_stack *s, struct frame **f)
+{
+ if (s->top < 0) {
+ DMERR("btree deletion stack empty");
+ return -EINVAL;
+ }
+
+ *f = s->spine + s->top;
+
+ return 0;
+}
+
+static int unprocessed_frames(struct del_stack *s)
+{
+ return s->top >= 0;
+}
+
+static void prefetch_children(struct del_stack *s, struct frame *f)
+{
+ unsigned i;
+ struct dm_block_manager *bm = dm_tm_get_bm(s->tm);
+
+ for (i = 0; i < f->nr_children; i++)
+ dm_bm_prefetch(bm, value64(f->n, i));
+}
+
+static bool is_internal_level(struct dm_btree_info *info, struct frame *f)
+{
+ return f->level < (info->levels - 1);
+}
+
+static int push_frame(struct del_stack *s, dm_block_t b, unsigned level)
+{
+ int r;
+ uint32_t ref_count;
+
+ if (s->top >= MAX_SPINE_DEPTH - 1) {
+ DMERR("btree deletion stack out of memory");
+ return -ENOMEM;
+ }
+
+ r = dm_tm_ref(s->tm, b, &ref_count);
+ if (r)
+ return r;
+
+ if (ref_count > 1)
+ /*
+ * This is a shared node, so we can just decrement it's
+ * reference counter and leave the children.
+ */
+ dm_tm_dec(s->tm, b);
+
+ else {
+ uint32_t flags;
+ struct frame *f = s->spine + ++s->top;
+
+ r = dm_tm_read_lock(s->tm, b, &btree_node_validator, &f->b);
+ if (r) {
+ s->top--;
+ return r;
+ }
+
+ f->n = dm_block_data(f->b);
+ f->level = level;
+ f->nr_children = le32_to_cpu(f->n->header.nr_entries);
+ f->current_child = 0;
+
+ flags = le32_to_cpu(f->n->header.flags);
+ if (flags & INTERNAL_NODE || is_internal_level(s->info, f))
+ prefetch_children(s, f);
+ }
+
+ return 0;
+}
+
+static void pop_frame(struct del_stack *s)
+{
+ struct frame *f = s->spine + s->top--;
+
+ dm_tm_dec(s->tm, dm_block_location(f->b));
+ dm_tm_unlock(s->tm, f->b);
+}
+
+int dm_btree_del(struct dm_btree_info *info, dm_block_t root)
+{
+ int r;
+ struct del_stack *s;
+
+ s = kmalloc(sizeof(*s), GFP_KERNEL);
+ if (!s)
+ return -ENOMEM;
+ s->info = info;
+ s->tm = info->tm;
+ s->top = -1;
+
+ r = push_frame(s, root, 0);
+ if (r)
+ goto out;
+
+ while (unprocessed_frames(s)) {
+ uint32_t flags;
+ struct frame *f;
+ dm_block_t b;
+
+ r = top_frame(s, &f);
+ if (r)
+ goto out;
+
+ if (f->current_child >= f->nr_children) {
+ pop_frame(s);
+ continue;
+ }
+
+ flags = le32_to_cpu(f->n->header.flags);
+ if (flags & INTERNAL_NODE) {
+ b = value64(f->n, f->current_child);
+ f->current_child++;
+ r = push_frame(s, b, f->level);
+ if (r)
+ goto out;
+
+ } else if (is_internal_level(info, f)) {
+ b = value64(f->n, f->current_child);
+ f->current_child++;
+ r = push_frame(s, b, f->level + 1);
+ if (r)
+ goto out;
+
+ } else {
+ if (info->value_type.dec) {
+ unsigned i;
+
+ for (i = 0; i < f->nr_children; i++)
+ info->value_type.dec(info->value_type.context,
+ value_ptr(f->n, i));
+ }
+ pop_frame(s);
+ }
+ }
+
+out:
+ kfree(s);
+ return r;
+}
+EXPORT_SYMBOL_GPL(dm_btree_del);
+
+/*----------------------------------------------------------------*/
+
+static int btree_lookup_raw(struct ro_spine *s, dm_block_t block, uint64_t key,
+ int (*search_fn)(struct btree_node *, uint64_t),
+ uint64_t *result_key, void *v, size_t value_size)
+{
+ int i, r;
+ uint32_t flags, nr_entries;
+
+ do {
+ r = ro_step(s, block);
+ if (r < 0)
+ return r;
+
+ i = search_fn(ro_node(s), key);
+
+ flags = le32_to_cpu(ro_node(s)->header.flags);
+ nr_entries = le32_to_cpu(ro_node(s)->header.nr_entries);
+ if (i < 0 || i >= nr_entries)
+ return -ENODATA;
+
+ if (flags & INTERNAL_NODE)
+ block = value64(ro_node(s), i);
+
+ } while (!(flags & LEAF_NODE));
+
+ *result_key = le64_to_cpu(ro_node(s)->keys[i]);
+ memcpy(v, value_ptr(ro_node(s), i), value_size);
+
+ return 0;
+}
+
+int dm_btree_lookup(struct dm_btree_info *info, dm_block_t root,
+ uint64_t *keys, void *value_le)
+{
+ unsigned level, last_level = info->levels - 1;
+ int r = -ENODATA;
+ uint64_t rkey;
+ __le64 internal_value_le;
+ struct ro_spine spine;
+
+ init_ro_spine(&spine, info);
+ for (level = 0; level < info->levels; level++) {
+ size_t size;
+ void *value_p;
+
+ if (level == last_level) {
+ value_p = value_le;
+ size = info->value_type.size;
+
+ } else {
+ value_p = &internal_value_le;
+ size = sizeof(uint64_t);
+ }
+
+ r = btree_lookup_raw(&spine, root, keys[level],
+ lower_bound, &rkey,
+ value_p, size);
+
+ if (!r) {
+ if (rkey != keys[level]) {
+ exit_ro_spine(&spine);
+ return -ENODATA;
+ }
+ } else {
+ exit_ro_spine(&spine);
+ return r;
+ }
+
+ root = le64_to_cpu(internal_value_le);
+ }
+ exit_ro_spine(&spine);
+
+ return r;
+}
+EXPORT_SYMBOL_GPL(dm_btree_lookup);
+
+/*
+ * Splits a node by creating a sibling node and shifting half the nodes
+ * contents across. Assumes there is a parent node, and it has room for
+ * another child.
+ *
+ * Before:
+ * +--------+
+ * | Parent |
+ * +--------+
+ * |
+ * v
+ * +----------+
+ * | A ++++++ |
+ * +----------+
+ *
+ *
+ * After:
+ * +--------+
+ * | Parent |
+ * +--------+
+ * | |
+ * v +------+
+ * +---------+ |
+ * | A* +++ | v
+ * +---------+ +-------+
+ * | B +++ |
+ * +-------+
+ *
+ * Where A* is a shadow of A.
+ */
+static int btree_split_sibling(struct shadow_spine *s, dm_block_t root,
+ unsigned parent_index, uint64_t key)
+{
+ int r;
+ size_t size;
+ unsigned nr_left, nr_right;
+ struct dm_block *left, *right, *parent;
+ struct btree_node *ln, *rn, *pn;
+ __le64 location;
+
+ left = shadow_current(s);
+
+ r = new_block(s->info, &right);
+ if (r < 0)
+ return r;
+
+ ln = dm_block_data(left);
+ rn = dm_block_data(right);
+
+ nr_left = le32_to_cpu(ln->header.nr_entries) / 2;
+ nr_right = le32_to_cpu(ln->header.nr_entries) - nr_left;
+
+ ln->header.nr_entries = cpu_to_le32(nr_left);
+
+ rn->header.flags = ln->header.flags;
+ rn->header.nr_entries = cpu_to_le32(nr_right);
+ rn->header.max_entries = ln->header.max_entries;
+ rn->header.value_size = ln->header.value_size;
+ memcpy(rn->keys, ln->keys + nr_left, nr_right * sizeof(rn->keys[0]));
+
+ size = le32_to_cpu(ln->header.flags) & INTERNAL_NODE ?
+ sizeof(uint64_t) : s->info->value_type.size;
+ memcpy(value_ptr(rn, 0), value_ptr(ln, nr_left),
+ size * nr_right);
+
+ /*
+ * Patch up the parent
+ */
+ parent = shadow_parent(s);
+
+ pn = dm_block_data(parent);
+ location = cpu_to_le64(dm_block_location(left));
+ __dm_bless_for_disk(&location);
+ memcpy_disk(value_ptr(pn, parent_index),
+ &location, sizeof(__le64));
+
+ location = cpu_to_le64(dm_block_location(right));
+ __dm_bless_for_disk(&location);
+
+ r = insert_at(sizeof(__le64), pn, parent_index + 1,
+ le64_to_cpu(rn->keys[0]), &location);
+ if (r)
+ return r;
+
+ if (key < le64_to_cpu(rn->keys[0])) {
+ unlock_block(s->info, right);
+ s->nodes[1] = left;
+ } else {
+ unlock_block(s->info, left);
+ s->nodes[1] = right;
+ }
+
+ return 0;
+}
+
+/*
+ * Splits a node by creating two new children beneath the given node.
+ *
+ * Before:
+ * +----------+
+ * | A ++++++ |
+ * +----------+
+ *
+ *
+ * After:
+ * +------------+
+ * | A (shadow) |
+ * +------------+
+ * | |
+ * +------+ +----+
+ * | |
+ * v v
+ * +-------+ +-------+
+ * | B +++ | | C +++ |
+ * +-------+ +-------+
+ */
+static int btree_split_beneath(struct shadow_spine *s, uint64_t key)
+{
+ int r;
+ size_t size;
+ unsigned nr_left, nr_right;
+ struct dm_block *left, *right, *new_parent;
+ struct btree_node *pn, *ln, *rn;
+ __le64 val;
+
+ new_parent = shadow_current(s);
+
+ r = new_block(s->info, &left);
+ if (r < 0)
+ return r;
+
+ r = new_block(s->info, &right);
+ if (r < 0) {
+ /* FIXME: put left */
+ return r;
+ }
+
+ pn = dm_block_data(new_parent);
+ ln = dm_block_data(left);
+ rn = dm_block_data(right);
+
+ nr_left = le32_to_cpu(pn->header.nr_entries) / 2;
+ nr_right = le32_to_cpu(pn->header.nr_entries) - nr_left;
+
+ ln->header.flags = pn->header.flags;
+ ln->header.nr_entries = cpu_to_le32(nr_left);
+ ln->header.max_entries = pn->header.max_entries;
+ ln->header.value_size = pn->header.value_size;
+
+ rn->header.flags = pn->header.flags;
+ rn->header.nr_entries = cpu_to_le32(nr_right);
+ rn->header.max_entries = pn->header.max_entries;
+ rn->header.value_size = pn->header.value_size;
+
+ memcpy(ln->keys, pn->keys, nr_left * sizeof(pn->keys[0]));
+ memcpy(rn->keys, pn->keys + nr_left, nr_right * sizeof(pn->keys[0]));
+
+ size = le32_to_cpu(pn->header.flags) & INTERNAL_NODE ?
+ sizeof(__le64) : s->info->value_type.size;
+ memcpy(value_ptr(ln, 0), value_ptr(pn, 0), nr_left * size);
+ memcpy(value_ptr(rn, 0), value_ptr(pn, nr_left),
+ nr_right * size);
+
+ /* new_parent should just point to l and r now */
+ pn->header.flags = cpu_to_le32(INTERNAL_NODE);
+ pn->header.nr_entries = cpu_to_le32(2);
+ pn->header.max_entries = cpu_to_le32(
+ calc_max_entries(sizeof(__le64),
+ dm_bm_block_size(
+ dm_tm_get_bm(s->info->tm))));
+ pn->header.value_size = cpu_to_le32(sizeof(__le64));
+
+ val = cpu_to_le64(dm_block_location(left));
+ __dm_bless_for_disk(&val);
+ pn->keys[0] = ln->keys[0];
+ memcpy_disk(value_ptr(pn, 0), &val, sizeof(__le64));
+
+ val = cpu_to_le64(dm_block_location(right));
+ __dm_bless_for_disk(&val);
+ pn->keys[1] = rn->keys[0];
+ memcpy_disk(value_ptr(pn, 1), &val, sizeof(__le64));
+
+ /*
+ * rejig the spine. This is ugly, since it knows too
+ * much about the spine
+ */
+ if (s->nodes[0] != new_parent) {
+ unlock_block(s->info, s->nodes[0]);
+ s->nodes[0] = new_parent;
+ }
+ if (key < le64_to_cpu(rn->keys[0])) {
+ unlock_block(s->info, right);
+ s->nodes[1] = left;
+ } else {
+ unlock_block(s->info, left);
+ s->nodes[1] = right;
+ }
+ s->count = 2;
+
+ return 0;
+}
+
+static int btree_insert_raw(struct shadow_spine *s, dm_block_t root,
+ struct dm_btree_value_type *vt,
+ uint64_t key, unsigned *index)
+{
+ int r, i = *index, top = 1;
+ struct btree_node *node;
+
+ for (;;) {
+ r = shadow_step(s, root, vt);
+ if (r < 0)
+ return r;
+
+ node = dm_block_data(shadow_current(s));
+
+ /*
+ * We have to patch up the parent node, ugly, but I don't
+ * see a way to do this automatically as part of the spine
+ * op.
+ */
+ if (shadow_has_parent(s) && i >= 0) { /* FIXME: second clause unness. */
+ __le64 location = cpu_to_le64(dm_block_location(shadow_current(s)));
+
+ __dm_bless_for_disk(&location);
+ memcpy_disk(value_ptr(dm_block_data(shadow_parent(s)), i),
+ &location, sizeof(__le64));
+ }
+
+ node = dm_block_data(shadow_current(s));
+
+ if (node->header.nr_entries == node->header.max_entries) {
+ if (top)
+ r = btree_split_beneath(s, key);
+ else
+ r = btree_split_sibling(s, root, i, key);
+
+ if (r < 0)
+ return r;
+ }
+
+ node = dm_block_data(shadow_current(s));
+
+ i = lower_bound(node, key);
+
+ if (le32_to_cpu(node->header.flags) & LEAF_NODE)
+ break;
+
+ if (i < 0) {
+ /* change the bounds on the lowest key */
+ node->keys[0] = cpu_to_le64(key);
+ i = 0;
+ }
+
+ root = value64(node, i);
+ top = 0;
+ }
+
+ if (i < 0 || le64_to_cpu(node->keys[i]) != key)
+ i++;
+
+ *index = i;
+ return 0;
+}
+
+static int insert(struct dm_btree_info *info, dm_block_t root,
+ uint64_t *keys, void *value, dm_block_t *new_root,
+ int *inserted)
+ __dm_written_to_disk(value)
+{
+ int r, need_insert;
+ unsigned level, index = -1, last_level = info->levels - 1;
+ dm_block_t block = root;
+ struct shadow_spine spine;
+ struct btree_node *n;
+ struct dm_btree_value_type le64_type;
+
+ le64_type.context = NULL;
+ le64_type.size = sizeof(__le64);
+ le64_type.inc = NULL;
+ le64_type.dec = NULL;
+ le64_type.equal = NULL;
+
+ init_shadow_spine(&spine, info);
+
+ for (level = 0; level < (info->levels - 1); level++) {
+ r = btree_insert_raw(&spine, block, &le64_type, keys[level], &index);
+ if (r < 0)
+ goto bad;
+
+ n = dm_block_data(shadow_current(&spine));
+ need_insert = ((index >= le32_to_cpu(n->header.nr_entries)) ||
+ (le64_to_cpu(n->keys[index]) != keys[level]));
+
+ if (need_insert) {
+ dm_block_t new_tree;
+ __le64 new_le;
+
+ r = dm_btree_empty(info, &new_tree);
+ if (r < 0)
+ goto bad;
+
+ new_le = cpu_to_le64(new_tree);
+ __dm_bless_for_disk(&new_le);
+
+ r = insert_at(sizeof(uint64_t), n, index,
+ keys[level], &new_le);
+ if (r)
+ goto bad;
+ }
+
+ if (level < last_level)
+ block = value64(n, index);
+ }
+
+ r = btree_insert_raw(&spine, block, &info->value_type,
+ keys[level], &index);
+ if (r < 0)
+ goto bad;
+
+ n = dm_block_data(shadow_current(&spine));
+ need_insert = ((index >= le32_to_cpu(n->header.nr_entries)) ||
+ (le64_to_cpu(n->keys[index]) != keys[level]));
+
+ if (need_insert) {
+ if (inserted)
+ *inserted = 1;
+
+ r = insert_at(info->value_type.size, n, index,
+ keys[level], value);
+ if (r)
+ goto bad_unblessed;
+ } else {
+ if (inserted)
+ *inserted = 0;
+
+ if (info->value_type.dec &&
+ (!info->value_type.equal ||
+ !info->value_type.equal(
+ info->value_type.context,
+ value_ptr(n, index),
+ value))) {
+ info->value_type.dec(info->value_type.context,
+ value_ptr(n, index));
+ }
+ memcpy_disk(value_ptr(n, index),
+ value, info->value_type.size);
+ }
+
+ *new_root = shadow_root(&spine);
+ exit_shadow_spine(&spine);
+
+ return 0;
+
+bad:
+ __dm_unbless_for_disk(value);
+bad_unblessed:
+ exit_shadow_spine(&spine);
+ return r;
+}
+
+int dm_btree_insert(struct dm_btree_info *info, dm_block_t root,
+ uint64_t *keys, void *value, dm_block_t *new_root)
+ __dm_written_to_disk(value)
+{
+ return insert(info, root, keys, value, new_root, NULL);
+}
+EXPORT_SYMBOL_GPL(dm_btree_insert);
+
+int dm_btree_insert_notify(struct dm_btree_info *info, dm_block_t root,
+ uint64_t *keys, void *value, dm_block_t *new_root,
+ int *inserted)
+ __dm_written_to_disk(value)
+{
+ return insert(info, root, keys, value, new_root, inserted);
+}
+EXPORT_SYMBOL_GPL(dm_btree_insert_notify);
+
+/*----------------------------------------------------------------*/
+
+static int find_key(struct ro_spine *s, dm_block_t block, bool find_highest,
+ uint64_t *result_key, dm_block_t *next_block)
+{
+ int i, r;
+ uint32_t flags;
+
+ do {
+ r = ro_step(s, block);
+ if (r < 0)
+ return r;
+
+ flags = le32_to_cpu(ro_node(s)->header.flags);
+ i = le32_to_cpu(ro_node(s)->header.nr_entries);
+ if (!i)
+ return -ENODATA;
+ else
+ i--;
+
+ if (find_highest)
+ *result_key = le64_to_cpu(ro_node(s)->keys[i]);
+ else
+ *result_key = le64_to_cpu(ro_node(s)->keys[0]);
+
+ if (next_block || flags & INTERNAL_NODE)
+ block = value64(ro_node(s), i);
+
+ } while (flags & INTERNAL_NODE);
+
+ if (next_block)
+ *next_block = block;
+ return 0;
+}
+
+static int dm_btree_find_key(struct dm_btree_info *info, dm_block_t root,
+ bool find_highest, uint64_t *result_keys)
+{
+ int r = 0, count = 0, level;
+ struct ro_spine spine;
+
+ init_ro_spine(&spine, info);
+ for (level = 0; level < info->levels; level++) {
+ r = find_key(&spine, root, find_highest, result_keys + level,
+ level == info->levels - 1 ? NULL : &root);
+ if (r == -ENODATA) {
+ r = 0;
+ break;
+
+ } else if (r)
+ break;
+
+ count++;
+ }
+ exit_ro_spine(&spine);
+
+ return r ? r : count;
+}
+
+int dm_btree_find_highest_key(struct dm_btree_info *info, dm_block_t root,
+ uint64_t *result_keys)
+{
+ return dm_btree_find_key(info, root, true, result_keys);
+}
+EXPORT_SYMBOL_GPL(dm_btree_find_highest_key);
+
+int dm_btree_find_lowest_key(struct dm_btree_info *info, dm_block_t root,
+ uint64_t *result_keys)
+{
+ return dm_btree_find_key(info, root, false, result_keys);
+}
+EXPORT_SYMBOL_GPL(dm_btree_find_lowest_key);
+
+/*----------------------------------------------------------------*/
+
+/*
+ * FIXME: We shouldn't use a recursive algorithm when we have limited stack
+ * space. Also this only works for single level trees.
+ */
+static int walk_node(struct dm_btree_info *info, dm_block_t block,
+ int (*fn)(void *context, uint64_t *keys, void *leaf),
+ void *context)
+{
+ int r;
+ unsigned i, nr;
+ struct dm_block *node;
+ struct btree_node *n;
+ uint64_t keys;
+
+ r = bn_read_lock(info, block, &node);
+ if (r)
+ return r;
+
+ n = dm_block_data(node);
+
+ nr = le32_to_cpu(n->header.nr_entries);
+ for (i = 0; i < nr; i++) {
+ if (le32_to_cpu(n->header.flags) & INTERNAL_NODE) {
+ r = walk_node(info, value64(n, i), fn, context);
+ if (r)
+ goto out;
+ } else {
+ keys = le64_to_cpu(*key_ptr(n, i));
+ r = fn(context, &keys, value_ptr(n, i));
+ if (r)
+ goto out;
+ }
+ }
+
+out:
+ dm_tm_unlock(info->tm, node);
+ return r;
+}
+
+int dm_btree_walk(struct dm_btree_info *info, dm_block_t root,
+ int (*fn)(void *context, uint64_t *keys, void *leaf),
+ void *context)
+{
+ BUG_ON(info->levels > 1);
+ return walk_node(info, root, fn, context);
+}
+EXPORT_SYMBOL_GPL(dm_btree_walk);
diff --git a/kernel/drivers/md/persistent-data/dm-btree.h b/kernel/drivers/md/persistent-data/dm-btree.h
new file mode 100644
index 000000000..dacfc3418
--- /dev/null
+++ b/kernel/drivers/md/persistent-data/dm-btree.h
@@ -0,0 +1,162 @@
+/*
+ * Copyright (C) 2011 Red Hat, Inc.
+ *
+ * This file is released under the GPL.
+ */
+#ifndef _LINUX_DM_BTREE_H
+#define _LINUX_DM_BTREE_H
+
+#include "dm-block-manager.h"
+
+struct dm_transaction_manager;
+
+/*----------------------------------------------------------------*/
+
+/*
+ * Annotations used to check on-disk metadata is handled as little-endian.
+ */
+#ifdef __CHECKER__
+# define __dm_written_to_disk(x) __releases(x)
+# define __dm_reads_from_disk(x) __acquires(x)
+# define __dm_bless_for_disk(x) __acquire(x)
+# define __dm_unbless_for_disk(x) __release(x)
+#else
+# define __dm_written_to_disk(x)
+# define __dm_reads_from_disk(x)
+# define __dm_bless_for_disk(x)
+# define __dm_unbless_for_disk(x)
+#endif
+
+/*----------------------------------------------------------------*/
+
+/*
+ * Manipulates hierarchical B+ trees with 64-bit keys and arbitrary-sized
+ * values.
+ */
+
+/*
+ * Information about the values stored within the btree.
+ */
+struct dm_btree_value_type {
+ void *context;
+
+ /*
+ * The size in bytes of each value.
+ */
+ uint32_t size;
+
+ /*
+ * Any of these methods can be safely set to NULL if you do not
+ * need the corresponding feature.
+ */
+
+ /*
+ * The btree is making a duplicate of the value, for instance
+ * because previously-shared btree nodes have now diverged.
+ * @value argument is the new copy that the copy function may modify.
+ * (Probably it just wants to increment a reference count
+ * somewhere.) This method is _not_ called for insertion of a new
+ * value: It is assumed the ref count is already 1.
+ */
+ void (*inc)(void *context, const void *value);
+
+ /*
+ * This value is being deleted. The btree takes care of freeing
+ * the memory pointed to by @value. Often the del function just
+ * needs to decrement a reference count somewhere.
+ */
+ void (*dec)(void *context, const void *value);
+
+ /*
+ * A test for equality between two values. When a value is
+ * overwritten with a new one, the old one has the dec method
+ * called _unless_ the new and old value are deemed equal.
+ */
+ int (*equal)(void *context, const void *value1, const void *value2);
+};
+
+/*
+ * The shape and contents of a btree.
+ */
+struct dm_btree_info {
+ struct dm_transaction_manager *tm;
+
+ /*
+ * Number of nested btrees. (Not the depth of a single tree.)
+ */
+ unsigned levels;
+ struct dm_btree_value_type value_type;
+};
+
+/*
+ * Set up an empty tree. O(1).
+ */
+int dm_btree_empty(struct dm_btree_info *info, dm_block_t *root);
+
+/*
+ * Delete a tree. O(n) - this is the slow one! It can also block, so
+ * please don't call it on an IO path.
+ */
+int dm_btree_del(struct dm_btree_info *info, dm_block_t root);
+
+/*
+ * All the lookup functions return -ENODATA if the key cannot be found.
+ */
+
+/*
+ * Tries to find a key that matches exactly. O(ln(n))
+ */
+int dm_btree_lookup(struct dm_btree_info *info, dm_block_t root,
+ uint64_t *keys, void *value_le);
+
+/*
+ * Insertion (or overwrite an existing value). O(ln(n))
+ */
+int dm_btree_insert(struct dm_btree_info *info, dm_block_t root,
+ uint64_t *keys, void *value, dm_block_t *new_root)
+ __dm_written_to_disk(value);
+
+/*
+ * A variant of insert that indicates whether it actually inserted or just
+ * overwrote. Useful if you're keeping track of the number of entries in a
+ * tree.
+ */
+int dm_btree_insert_notify(struct dm_btree_info *info, dm_block_t root,
+ uint64_t *keys, void *value, dm_block_t *new_root,
+ int *inserted)
+ __dm_written_to_disk(value);
+
+/*
+ * Remove a key if present. This doesn't remove empty sub trees. Normally
+ * subtrees represent a separate entity, like a snapshot map, so this is
+ * correct behaviour. O(ln(n)).
+ */
+int dm_btree_remove(struct dm_btree_info *info, dm_block_t root,
+ uint64_t *keys, dm_block_t *new_root);
+
+/*
+ * Returns < 0 on failure. Otherwise the number of key entries that have
+ * been filled out. Remember trees can have zero entries, and as such have
+ * no lowest key.
+ */
+int dm_btree_find_lowest_key(struct dm_btree_info *info, dm_block_t root,
+ uint64_t *result_keys);
+
+/*
+ * Returns < 0 on failure. Otherwise the number of key entries that have
+ * been filled out. Remember trees can have zero entries, and as such have
+ * no highest key.
+ */
+int dm_btree_find_highest_key(struct dm_btree_info *info, dm_block_t root,
+ uint64_t *result_keys);
+
+/*
+ * Iterate through the a btree, calling fn() on each entry.
+ * It only works for single level trees and is internally recursive, so
+ * monitor stack usage carefully.
+ */
+int dm_btree_walk(struct dm_btree_info *info, dm_block_t root,
+ int (*fn)(void *context, uint64_t *keys, void *leaf),
+ void *context);
+
+#endif /* _LINUX_DM_BTREE_H */
diff --git a/kernel/drivers/md/persistent-data/dm-persistent-data-internal.h b/kernel/drivers/md/persistent-data/dm-persistent-data-internal.h
new file mode 100644
index 000000000..c49e26fff
--- /dev/null
+++ b/kernel/drivers/md/persistent-data/dm-persistent-data-internal.h
@@ -0,0 +1,19 @@
+/*
+ * Copyright (C) 2011 Red Hat, Inc.
+ *
+ * This file is released under the GPL.
+ */
+
+#ifndef _DM_PERSISTENT_DATA_INTERNAL_H
+#define _DM_PERSISTENT_DATA_INTERNAL_H
+
+#include "dm-block-manager.h"
+
+static inline unsigned dm_hash_block(dm_block_t b, unsigned hash_mask)
+{
+ const unsigned BIG_PRIME = 4294967291UL;
+
+ return (((unsigned) b) * BIG_PRIME) & hash_mask;
+}
+
+#endif /* _PERSISTENT_DATA_INTERNAL_H */
diff --git a/kernel/drivers/md/persistent-data/dm-space-map-common.c b/kernel/drivers/md/persistent-data/dm-space-map-common.c
new file mode 100644
index 000000000..aacbe70c2
--- /dev/null
+++ b/kernel/drivers/md/persistent-data/dm-space-map-common.c
@@ -0,0 +1,751 @@
+/*
+ * Copyright (C) 2011 Red Hat, Inc.
+ *
+ * This file is released under the GPL.
+ */
+
+#include "dm-space-map-common.h"
+#include "dm-transaction-manager.h"
+
+#include <linux/bitops.h>
+#include <linux/device-mapper.h>
+
+#define DM_MSG_PREFIX "space map common"
+
+/*----------------------------------------------------------------*/
+
+/*
+ * Index validator.
+ */
+#define INDEX_CSUM_XOR 160478
+
+static void index_prepare_for_write(struct dm_block_validator *v,
+ struct dm_block *b,
+ size_t block_size)
+{
+ struct disk_metadata_index *mi_le = dm_block_data(b);
+
+ mi_le->blocknr = cpu_to_le64(dm_block_location(b));
+ mi_le->csum = cpu_to_le32(dm_bm_checksum(&mi_le->padding,
+ block_size - sizeof(__le32),
+ INDEX_CSUM_XOR));
+}
+
+static int index_check(struct dm_block_validator *v,
+ struct dm_block *b,
+ size_t block_size)
+{
+ struct disk_metadata_index *mi_le = dm_block_data(b);
+ __le32 csum_disk;
+
+ if (dm_block_location(b) != le64_to_cpu(mi_le->blocknr)) {
+ DMERR_LIMIT("index_check failed: blocknr %llu != wanted %llu",
+ le64_to_cpu(mi_le->blocknr), dm_block_location(b));
+ return -ENOTBLK;
+ }
+
+ csum_disk = cpu_to_le32(dm_bm_checksum(&mi_le->padding,
+ block_size - sizeof(__le32),
+ INDEX_CSUM_XOR));
+ if (csum_disk != mi_le->csum) {
+ DMERR_LIMIT("index_check failed: csum %u != wanted %u",
+ le32_to_cpu(csum_disk), le32_to_cpu(mi_le->csum));
+ return -EILSEQ;
+ }
+
+ return 0;
+}
+
+static struct dm_block_validator index_validator = {
+ .name = "index",
+ .prepare_for_write = index_prepare_for_write,
+ .check = index_check
+};
+
+/*----------------------------------------------------------------*/
+
+/*
+ * Bitmap validator
+ */
+#define BITMAP_CSUM_XOR 240779
+
+static void bitmap_prepare_for_write(struct dm_block_validator *v,
+ struct dm_block *b,
+ size_t block_size)
+{
+ struct disk_bitmap_header *disk_header = dm_block_data(b);
+
+ disk_header->blocknr = cpu_to_le64(dm_block_location(b));
+ disk_header->csum = cpu_to_le32(dm_bm_checksum(&disk_header->not_used,
+ block_size - sizeof(__le32),
+ BITMAP_CSUM_XOR));
+}
+
+static int bitmap_check(struct dm_block_validator *v,
+ struct dm_block *b,
+ size_t block_size)
+{
+ struct disk_bitmap_header *disk_header = dm_block_data(b);
+ __le32 csum_disk;
+
+ if (dm_block_location(b) != le64_to_cpu(disk_header->blocknr)) {
+ DMERR_LIMIT("bitmap check failed: blocknr %llu != wanted %llu",
+ le64_to_cpu(disk_header->blocknr), dm_block_location(b));
+ return -ENOTBLK;
+ }
+
+ csum_disk = cpu_to_le32(dm_bm_checksum(&disk_header->not_used,
+ block_size - sizeof(__le32),
+ BITMAP_CSUM_XOR));
+ if (csum_disk != disk_header->csum) {
+ DMERR_LIMIT("bitmap check failed: csum %u != wanted %u",
+ le32_to_cpu(csum_disk), le32_to_cpu(disk_header->csum));
+ return -EILSEQ;
+ }
+
+ return 0;
+}
+
+static struct dm_block_validator dm_sm_bitmap_validator = {
+ .name = "sm_bitmap",
+ .prepare_for_write = bitmap_prepare_for_write,
+ .check = bitmap_check
+};
+
+/*----------------------------------------------------------------*/
+
+#define ENTRIES_PER_WORD 32
+#define ENTRIES_SHIFT 5
+
+static void *dm_bitmap_data(struct dm_block *b)
+{
+ return dm_block_data(b) + sizeof(struct disk_bitmap_header);
+}
+
+#define WORD_MASK_HIGH 0xAAAAAAAAAAAAAAAAULL
+
+static unsigned bitmap_word_used(void *addr, unsigned b)
+{
+ __le64 *words_le = addr;
+ __le64 *w_le = words_le + (b >> ENTRIES_SHIFT);
+
+ uint64_t bits = le64_to_cpu(*w_le);
+ uint64_t mask = (bits + WORD_MASK_HIGH + 1) & WORD_MASK_HIGH;
+
+ return !(~bits & mask);
+}
+
+static unsigned sm_lookup_bitmap(void *addr, unsigned b)
+{
+ __le64 *words_le = addr;
+ __le64 *w_le = words_le + (b >> ENTRIES_SHIFT);
+ unsigned hi, lo;
+
+ b = (b & (ENTRIES_PER_WORD - 1)) << 1;
+ hi = !!test_bit_le(b, (void *) w_le);
+ lo = !!test_bit_le(b + 1, (void *) w_le);
+ return (hi << 1) | lo;
+}
+
+static void sm_set_bitmap(void *addr, unsigned b, unsigned val)
+{
+ __le64 *words_le = addr;
+ __le64 *w_le = words_le + (b >> ENTRIES_SHIFT);
+
+ b = (b & (ENTRIES_PER_WORD - 1)) << 1;
+
+ if (val & 2)
+ __set_bit_le(b, (void *) w_le);
+ else
+ __clear_bit_le(b, (void *) w_le);
+
+ if (val & 1)
+ __set_bit_le(b + 1, (void *) w_le);
+ else
+ __clear_bit_le(b + 1, (void *) w_le);
+}
+
+static int sm_find_free(void *addr, unsigned begin, unsigned end,
+ unsigned *result)
+{
+ while (begin < end) {
+ if (!(begin & (ENTRIES_PER_WORD - 1)) &&
+ bitmap_word_used(addr, begin)) {
+ begin += ENTRIES_PER_WORD;
+ continue;
+ }
+
+ if (!sm_lookup_bitmap(addr, begin)) {
+ *result = begin;
+ return 0;
+ }
+
+ begin++;
+ }
+
+ return -ENOSPC;
+}
+
+/*----------------------------------------------------------------*/
+
+static int sm_ll_init(struct ll_disk *ll, struct dm_transaction_manager *tm)
+{
+ ll->tm = tm;
+
+ ll->bitmap_info.tm = tm;
+ ll->bitmap_info.levels = 1;
+
+ /*
+ * Because the new bitmap blocks are created via a shadow
+ * operation, the old entry has already had its reference count
+ * decremented and we don't need the btree to do any bookkeeping.
+ */
+ ll->bitmap_info.value_type.size = sizeof(struct disk_index_entry);
+ ll->bitmap_info.value_type.inc = NULL;
+ ll->bitmap_info.value_type.dec = NULL;
+ ll->bitmap_info.value_type.equal = NULL;
+
+ ll->ref_count_info.tm = tm;
+ ll->ref_count_info.levels = 1;
+ ll->ref_count_info.value_type.size = sizeof(uint32_t);
+ ll->ref_count_info.value_type.inc = NULL;
+ ll->ref_count_info.value_type.dec = NULL;
+ ll->ref_count_info.value_type.equal = NULL;
+
+ ll->block_size = dm_bm_block_size(dm_tm_get_bm(tm));
+
+ if (ll->block_size > (1 << 30)) {
+ DMERR("block size too big to hold bitmaps");
+ return -EINVAL;
+ }
+
+ ll->entries_per_block = (ll->block_size - sizeof(struct disk_bitmap_header)) *
+ ENTRIES_PER_BYTE;
+ ll->nr_blocks = 0;
+ ll->bitmap_root = 0;
+ ll->ref_count_root = 0;
+ ll->bitmap_index_changed = false;
+
+ return 0;
+}
+
+int sm_ll_extend(struct ll_disk *ll, dm_block_t extra_blocks)
+{
+ int r;
+ dm_block_t i, nr_blocks, nr_indexes;
+ unsigned old_blocks, blocks;
+
+ nr_blocks = ll->nr_blocks + extra_blocks;
+ old_blocks = dm_sector_div_up(ll->nr_blocks, ll->entries_per_block);
+ blocks = dm_sector_div_up(nr_blocks, ll->entries_per_block);
+
+ nr_indexes = dm_sector_div_up(nr_blocks, ll->entries_per_block);
+ if (nr_indexes > ll->max_entries(ll)) {
+ DMERR("space map too large");
+ return -EINVAL;
+ }
+
+ /*
+ * We need to set this before the dm_tm_new_block() call below.
+ */
+ ll->nr_blocks = nr_blocks;
+ for (i = old_blocks; i < blocks; i++) {
+ struct dm_block *b;
+ struct disk_index_entry idx;
+
+ r = dm_tm_new_block(ll->tm, &dm_sm_bitmap_validator, &b);
+ if (r < 0)
+ return r;
+
+ idx.blocknr = cpu_to_le64(dm_block_location(b));
+
+ r = dm_tm_unlock(ll->tm, b);
+ if (r < 0)
+ return r;
+
+ idx.nr_free = cpu_to_le32(ll->entries_per_block);
+ idx.none_free_before = 0;
+
+ r = ll->save_ie(ll, i, &idx);
+ if (r < 0)
+ return r;
+ }
+
+ return 0;
+}
+
+int sm_ll_lookup_bitmap(struct ll_disk *ll, dm_block_t b, uint32_t *result)
+{
+ int r;
+ dm_block_t index = b;
+ struct disk_index_entry ie_disk;
+ struct dm_block *blk;
+
+ b = do_div(index, ll->entries_per_block);
+ r = ll->load_ie(ll, index, &ie_disk);
+ if (r < 0)
+ return r;
+
+ r = dm_tm_read_lock(ll->tm, le64_to_cpu(ie_disk.blocknr),
+ &dm_sm_bitmap_validator, &blk);
+ if (r < 0)
+ return r;
+
+ *result = sm_lookup_bitmap(dm_bitmap_data(blk), b);
+
+ return dm_tm_unlock(ll->tm, blk);
+}
+
+static int sm_ll_lookup_big_ref_count(struct ll_disk *ll, dm_block_t b,
+ uint32_t *result)
+{
+ __le32 le_rc;
+ int r;
+
+ r = dm_btree_lookup(&ll->ref_count_info, ll->ref_count_root, &b, &le_rc);
+ if (r < 0)
+ return r;
+
+ *result = le32_to_cpu(le_rc);
+
+ return r;
+}
+
+int sm_ll_lookup(struct ll_disk *ll, dm_block_t b, uint32_t *result)
+{
+ int r = sm_ll_lookup_bitmap(ll, b, result);
+
+ if (r)
+ return r;
+
+ if (*result != 3)
+ return r;
+
+ return sm_ll_lookup_big_ref_count(ll, b, result);
+}
+
+int sm_ll_find_free_block(struct ll_disk *ll, dm_block_t begin,
+ dm_block_t end, dm_block_t *result)
+{
+ int r;
+ struct disk_index_entry ie_disk;
+ dm_block_t i, index_begin = begin;
+ dm_block_t index_end = dm_sector_div_up(end, ll->entries_per_block);
+
+ /*
+ * FIXME: Use shifts
+ */
+ begin = do_div(index_begin, ll->entries_per_block);
+ end = do_div(end, ll->entries_per_block);
+
+ for (i = index_begin; i < index_end; i++, begin = 0) {
+ struct dm_block *blk;
+ unsigned position;
+ uint32_t bit_end;
+
+ r = ll->load_ie(ll, i, &ie_disk);
+ if (r < 0)
+ return r;
+
+ if (le32_to_cpu(ie_disk.nr_free) == 0)
+ continue;
+
+ r = dm_tm_read_lock(ll->tm, le64_to_cpu(ie_disk.blocknr),
+ &dm_sm_bitmap_validator, &blk);
+ if (r < 0)
+ return r;
+
+ bit_end = (i == index_end - 1) ? end : ll->entries_per_block;
+
+ r = sm_find_free(dm_bitmap_data(blk),
+ max_t(unsigned, begin, le32_to_cpu(ie_disk.none_free_before)),
+ bit_end, &position);
+ if (r == -ENOSPC) {
+ /*
+ * This might happen because we started searching
+ * part way through the bitmap.
+ */
+ dm_tm_unlock(ll->tm, blk);
+ continue;
+
+ } else if (r < 0) {
+ dm_tm_unlock(ll->tm, blk);
+ return r;
+ }
+
+ r = dm_tm_unlock(ll->tm, blk);
+ if (r < 0)
+ return r;
+
+ *result = i * ll->entries_per_block + (dm_block_t) position;
+ return 0;
+ }
+
+ return -ENOSPC;
+}
+
+static int sm_ll_mutate(struct ll_disk *ll, dm_block_t b,
+ int (*mutator)(void *context, uint32_t old, uint32_t *new),
+ void *context, enum allocation_event *ev)
+{
+ int r;
+ uint32_t bit, old, ref_count;
+ struct dm_block *nb;
+ dm_block_t index = b;
+ struct disk_index_entry ie_disk;
+ void *bm_le;
+ int inc;
+
+ bit = do_div(index, ll->entries_per_block);
+ r = ll->load_ie(ll, index, &ie_disk);
+ if (r < 0)
+ return r;
+
+ r = dm_tm_shadow_block(ll->tm, le64_to_cpu(ie_disk.blocknr),
+ &dm_sm_bitmap_validator, &nb, &inc);
+ if (r < 0) {
+ DMERR("dm_tm_shadow_block() failed");
+ return r;
+ }
+ ie_disk.blocknr = cpu_to_le64(dm_block_location(nb));
+
+ bm_le = dm_bitmap_data(nb);
+ old = sm_lookup_bitmap(bm_le, bit);
+
+ if (old > 2) {
+ r = sm_ll_lookup_big_ref_count(ll, b, &old);
+ if (r < 0) {
+ dm_tm_unlock(ll->tm, nb);
+ return r;
+ }
+ }
+
+ r = mutator(context, old, &ref_count);
+ if (r) {
+ dm_tm_unlock(ll->tm, nb);
+ return r;
+ }
+
+ if (ref_count <= 2) {
+ sm_set_bitmap(bm_le, bit, ref_count);
+
+ r = dm_tm_unlock(ll->tm, nb);
+ if (r < 0)
+ return r;
+
+ if (old > 2) {
+ r = dm_btree_remove(&ll->ref_count_info,
+ ll->ref_count_root,
+ &b, &ll->ref_count_root);
+ if (r)
+ return r;
+ }
+
+ } else {
+ __le32 le_rc = cpu_to_le32(ref_count);
+
+ sm_set_bitmap(bm_le, bit, 3);
+ r = dm_tm_unlock(ll->tm, nb);
+ if (r < 0)
+ return r;
+
+ __dm_bless_for_disk(&le_rc);
+ r = dm_btree_insert(&ll->ref_count_info, ll->ref_count_root,
+ &b, &le_rc, &ll->ref_count_root);
+ if (r < 0) {
+ DMERR("ref count insert failed");
+ return r;
+ }
+ }
+
+ if (ref_count && !old) {
+ *ev = SM_ALLOC;
+ ll->nr_allocated++;
+ le32_add_cpu(&ie_disk.nr_free, -1);
+ if (le32_to_cpu(ie_disk.none_free_before) == bit)
+ ie_disk.none_free_before = cpu_to_le32(bit + 1);
+
+ } else if (old && !ref_count) {
+ *ev = SM_FREE;
+ ll->nr_allocated--;
+ le32_add_cpu(&ie_disk.nr_free, 1);
+ ie_disk.none_free_before = cpu_to_le32(min(le32_to_cpu(ie_disk.none_free_before), bit));
+ }
+
+ return ll->save_ie(ll, index, &ie_disk);
+}
+
+static int set_ref_count(void *context, uint32_t old, uint32_t *new)
+{
+ *new = *((uint32_t *) context);
+ return 0;
+}
+
+int sm_ll_insert(struct ll_disk *ll, dm_block_t b,
+ uint32_t ref_count, enum allocation_event *ev)
+{
+ return sm_ll_mutate(ll, b, set_ref_count, &ref_count, ev);
+}
+
+static int inc_ref_count(void *context, uint32_t old, uint32_t *new)
+{
+ *new = old + 1;
+ return 0;
+}
+
+int sm_ll_inc(struct ll_disk *ll, dm_block_t b, enum allocation_event *ev)
+{
+ return sm_ll_mutate(ll, b, inc_ref_count, NULL, ev);
+}
+
+static int dec_ref_count(void *context, uint32_t old, uint32_t *new)
+{
+ if (!old) {
+ DMERR_LIMIT("unable to decrement a reference count below 0");
+ return -EINVAL;
+ }
+
+ *new = old - 1;
+ return 0;
+}
+
+int sm_ll_dec(struct ll_disk *ll, dm_block_t b, enum allocation_event *ev)
+{
+ return sm_ll_mutate(ll, b, dec_ref_count, NULL, ev);
+}
+
+int sm_ll_commit(struct ll_disk *ll)
+{
+ int r = 0;
+
+ if (ll->bitmap_index_changed) {
+ r = ll->commit(ll);
+ if (!r)
+ ll->bitmap_index_changed = false;
+ }
+
+ return r;
+}
+
+/*----------------------------------------------------------------*/
+
+static int metadata_ll_load_ie(struct ll_disk *ll, dm_block_t index,
+ struct disk_index_entry *ie)
+{
+ memcpy(ie, ll->mi_le.index + index, sizeof(*ie));
+ return 0;
+}
+
+static int metadata_ll_save_ie(struct ll_disk *ll, dm_block_t index,
+ struct disk_index_entry *ie)
+{
+ ll->bitmap_index_changed = true;
+ memcpy(ll->mi_le.index + index, ie, sizeof(*ie));
+ return 0;
+}
+
+static int metadata_ll_init_index(struct ll_disk *ll)
+{
+ int r;
+ struct dm_block *b;
+
+ r = dm_tm_new_block(ll->tm, &index_validator, &b);
+ if (r < 0)
+ return r;
+
+ memcpy(dm_block_data(b), &ll->mi_le, sizeof(ll->mi_le));
+ ll->bitmap_root = dm_block_location(b);
+
+ return dm_tm_unlock(ll->tm, b);
+}
+
+static int metadata_ll_open(struct ll_disk *ll)
+{
+ int r;
+ struct dm_block *block;
+
+ r = dm_tm_read_lock(ll->tm, ll->bitmap_root,
+ &index_validator, &block);
+ if (r)
+ return r;
+
+ memcpy(&ll->mi_le, dm_block_data(block), sizeof(ll->mi_le));
+ return dm_tm_unlock(ll->tm, block);
+}
+
+static dm_block_t metadata_ll_max_entries(struct ll_disk *ll)
+{
+ return MAX_METADATA_BITMAPS;
+}
+
+static int metadata_ll_commit(struct ll_disk *ll)
+{
+ int r, inc;
+ struct dm_block *b;
+
+ r = dm_tm_shadow_block(ll->tm, ll->bitmap_root, &index_validator, &b, &inc);
+ if (r)
+ return r;
+
+ memcpy(dm_block_data(b), &ll->mi_le, sizeof(ll->mi_le));
+ ll->bitmap_root = dm_block_location(b);
+
+ return dm_tm_unlock(ll->tm, b);
+}
+
+int sm_ll_new_metadata(struct ll_disk *ll, struct dm_transaction_manager *tm)
+{
+ int r;
+
+ r = sm_ll_init(ll, tm);
+ if (r < 0)
+ return r;
+
+ ll->load_ie = metadata_ll_load_ie;
+ ll->save_ie = metadata_ll_save_ie;
+ ll->init_index = metadata_ll_init_index;
+ ll->open_index = metadata_ll_open;
+ ll->max_entries = metadata_ll_max_entries;
+ ll->commit = metadata_ll_commit;
+
+ ll->nr_blocks = 0;
+ ll->nr_allocated = 0;
+
+ r = ll->init_index(ll);
+ if (r < 0)
+ return r;
+
+ r = dm_btree_empty(&ll->ref_count_info, &ll->ref_count_root);
+ if (r < 0)
+ return r;
+
+ return 0;
+}
+
+int sm_ll_open_metadata(struct ll_disk *ll, struct dm_transaction_manager *tm,
+ void *root_le, size_t len)
+{
+ int r;
+ struct disk_sm_root *smr = root_le;
+
+ if (len < sizeof(struct disk_sm_root)) {
+ DMERR("sm_metadata root too small");
+ return -ENOMEM;
+ }
+
+ r = sm_ll_init(ll, tm);
+ if (r < 0)
+ return r;
+
+ ll->load_ie = metadata_ll_load_ie;
+ ll->save_ie = metadata_ll_save_ie;
+ ll->init_index = metadata_ll_init_index;
+ ll->open_index = metadata_ll_open;
+ ll->max_entries = metadata_ll_max_entries;
+ ll->commit = metadata_ll_commit;
+
+ ll->nr_blocks = le64_to_cpu(smr->nr_blocks);
+ ll->nr_allocated = le64_to_cpu(smr->nr_allocated);
+ ll->bitmap_root = le64_to_cpu(smr->bitmap_root);
+ ll->ref_count_root = le64_to_cpu(smr->ref_count_root);
+
+ return ll->open_index(ll);
+}
+
+/*----------------------------------------------------------------*/
+
+static int disk_ll_load_ie(struct ll_disk *ll, dm_block_t index,
+ struct disk_index_entry *ie)
+{
+ return dm_btree_lookup(&ll->bitmap_info, ll->bitmap_root, &index, ie);
+}
+
+static int disk_ll_save_ie(struct ll_disk *ll, dm_block_t index,
+ struct disk_index_entry *ie)
+{
+ __dm_bless_for_disk(ie);
+ return dm_btree_insert(&ll->bitmap_info, ll->bitmap_root,
+ &index, ie, &ll->bitmap_root);
+}
+
+static int disk_ll_init_index(struct ll_disk *ll)
+{
+ return dm_btree_empty(&ll->bitmap_info, &ll->bitmap_root);
+}
+
+static int disk_ll_open(struct ll_disk *ll)
+{
+ /* nothing to do */
+ return 0;
+}
+
+static dm_block_t disk_ll_max_entries(struct ll_disk *ll)
+{
+ return -1ULL;
+}
+
+static int disk_ll_commit(struct ll_disk *ll)
+{
+ return 0;
+}
+
+int sm_ll_new_disk(struct ll_disk *ll, struct dm_transaction_manager *tm)
+{
+ int r;
+
+ r = sm_ll_init(ll, tm);
+ if (r < 0)
+ return r;
+
+ ll->load_ie = disk_ll_load_ie;
+ ll->save_ie = disk_ll_save_ie;
+ ll->init_index = disk_ll_init_index;
+ ll->open_index = disk_ll_open;
+ ll->max_entries = disk_ll_max_entries;
+ ll->commit = disk_ll_commit;
+
+ ll->nr_blocks = 0;
+ ll->nr_allocated = 0;
+
+ r = ll->init_index(ll);
+ if (r < 0)
+ return r;
+
+ r = dm_btree_empty(&ll->ref_count_info, &ll->ref_count_root);
+ if (r < 0)
+ return r;
+
+ return 0;
+}
+
+int sm_ll_open_disk(struct ll_disk *ll, struct dm_transaction_manager *tm,
+ void *root_le, size_t len)
+{
+ int r;
+ struct disk_sm_root *smr = root_le;
+
+ if (len < sizeof(struct disk_sm_root)) {
+ DMERR("sm_metadata root too small");
+ return -ENOMEM;
+ }
+
+ r = sm_ll_init(ll, tm);
+ if (r < 0)
+ return r;
+
+ ll->load_ie = disk_ll_load_ie;
+ ll->save_ie = disk_ll_save_ie;
+ ll->init_index = disk_ll_init_index;
+ ll->open_index = disk_ll_open;
+ ll->max_entries = disk_ll_max_entries;
+ ll->commit = disk_ll_commit;
+
+ ll->nr_blocks = le64_to_cpu(smr->nr_blocks);
+ ll->nr_allocated = le64_to_cpu(smr->nr_allocated);
+ ll->bitmap_root = le64_to_cpu(smr->bitmap_root);
+ ll->ref_count_root = le64_to_cpu(smr->ref_count_root);
+
+ return ll->open_index(ll);
+}
+
+/*----------------------------------------------------------------*/
diff --git a/kernel/drivers/md/persistent-data/dm-space-map-common.h b/kernel/drivers/md/persistent-data/dm-space-map-common.h
new file mode 100644
index 000000000..b3078d5ed
--- /dev/null
+++ b/kernel/drivers/md/persistent-data/dm-space-map-common.h
@@ -0,0 +1,127 @@
+/*
+ * Copyright (C) 2011 Red Hat, Inc.
+ *
+ * This file is released under the GPL.
+ */
+
+#ifndef DM_SPACE_MAP_COMMON_H
+#define DM_SPACE_MAP_COMMON_H
+
+#include "dm-btree.h"
+
+/*----------------------------------------------------------------*/
+
+/*
+ * Low level disk format
+ *
+ * Bitmap btree
+ * ------------
+ *
+ * Each value stored in the btree is an index_entry. This points to a
+ * block that is used as a bitmap. Within the bitmap hold 2 bits per
+ * entry, which represent UNUSED = 0, REF_COUNT = 1, REF_COUNT = 2 and
+ * REF_COUNT = many.
+ *
+ * Refcount btree
+ * --------------
+ *
+ * Any entry that has a ref count higher than 2 gets entered in the ref
+ * count tree. The leaf values for this tree is the 32-bit ref count.
+ */
+
+struct disk_index_entry {
+ __le64 blocknr;
+ __le32 nr_free;
+ __le32 none_free_before;
+} __packed;
+
+
+#define MAX_METADATA_BITMAPS 255
+struct disk_metadata_index {
+ __le32 csum;
+ __le32 padding;
+ __le64 blocknr;
+
+ struct disk_index_entry index[MAX_METADATA_BITMAPS];
+} __packed;
+
+struct ll_disk;
+
+typedef int (*load_ie_fn)(struct ll_disk *ll, dm_block_t index, struct disk_index_entry *result);
+typedef int (*save_ie_fn)(struct ll_disk *ll, dm_block_t index, struct disk_index_entry *ie);
+typedef int (*init_index_fn)(struct ll_disk *ll);
+typedef int (*open_index_fn)(struct ll_disk *ll);
+typedef dm_block_t (*max_index_entries_fn)(struct ll_disk *ll);
+typedef int (*commit_fn)(struct ll_disk *ll);
+
+struct ll_disk {
+ struct dm_transaction_manager *tm;
+ struct dm_btree_info bitmap_info;
+ struct dm_btree_info ref_count_info;
+
+ uint32_t block_size;
+ uint32_t entries_per_block;
+ dm_block_t nr_blocks;
+ dm_block_t nr_allocated;
+
+ /*
+ * bitmap_root may be a btree root or a simple index.
+ */
+ dm_block_t bitmap_root;
+
+ dm_block_t ref_count_root;
+
+ struct disk_metadata_index mi_le;
+ load_ie_fn load_ie;
+ save_ie_fn save_ie;
+ init_index_fn init_index;
+ open_index_fn open_index;
+ max_index_entries_fn max_entries;
+ commit_fn commit;
+ bool bitmap_index_changed:1;
+};
+
+struct disk_sm_root {
+ __le64 nr_blocks;
+ __le64 nr_allocated;
+ __le64 bitmap_root;
+ __le64 ref_count_root;
+} __packed;
+
+#define ENTRIES_PER_BYTE 4
+
+struct disk_bitmap_header {
+ __le32 csum;
+ __le32 not_used;
+ __le64 blocknr;
+} __packed;
+
+enum allocation_event {
+ SM_NONE,
+ SM_ALLOC,
+ SM_FREE,
+};
+
+/*----------------------------------------------------------------*/
+
+int sm_ll_extend(struct ll_disk *ll, dm_block_t extra_blocks);
+int sm_ll_lookup_bitmap(struct ll_disk *ll, dm_block_t b, uint32_t *result);
+int sm_ll_lookup(struct ll_disk *ll, dm_block_t b, uint32_t *result);
+int sm_ll_find_free_block(struct ll_disk *ll, dm_block_t begin,
+ dm_block_t end, dm_block_t *result);
+int sm_ll_insert(struct ll_disk *ll, dm_block_t b, uint32_t ref_count, enum allocation_event *ev);
+int sm_ll_inc(struct ll_disk *ll, dm_block_t b, enum allocation_event *ev);
+int sm_ll_dec(struct ll_disk *ll, dm_block_t b, enum allocation_event *ev);
+int sm_ll_commit(struct ll_disk *ll);
+
+int sm_ll_new_metadata(struct ll_disk *ll, struct dm_transaction_manager *tm);
+int sm_ll_open_metadata(struct ll_disk *ll, struct dm_transaction_manager *tm,
+ void *root_le, size_t len);
+
+int sm_ll_new_disk(struct ll_disk *ll, struct dm_transaction_manager *tm);
+int sm_ll_open_disk(struct ll_disk *ll, struct dm_transaction_manager *tm,
+ void *root_le, size_t len);
+
+/*----------------------------------------------------------------*/
+
+#endif /* DM_SPACE_MAP_COMMON_H */
diff --git a/kernel/drivers/md/persistent-data/dm-space-map-disk.c b/kernel/drivers/md/persistent-data/dm-space-map-disk.c
new file mode 100644
index 000000000..ebb280a14
--- /dev/null
+++ b/kernel/drivers/md/persistent-data/dm-space-map-disk.c
@@ -0,0 +1,305 @@
+/*
+ * Copyright (C) 2011 Red Hat, Inc.
+ *
+ * This file is released under the GPL.
+ */
+
+#include "dm-space-map-common.h"
+#include "dm-space-map-disk.h"
+#include "dm-space-map.h"
+#include "dm-transaction-manager.h"
+
+#include <linux/list.h>
+#include <linux/slab.h>
+#include <linux/export.h>
+#include <linux/device-mapper.h>
+
+#define DM_MSG_PREFIX "space map disk"
+
+/*----------------------------------------------------------------*/
+
+/*
+ * Space map interface.
+ */
+struct sm_disk {
+ struct dm_space_map sm;
+
+ struct ll_disk ll;
+ struct ll_disk old_ll;
+
+ dm_block_t begin;
+ dm_block_t nr_allocated_this_transaction;
+};
+
+static void sm_disk_destroy(struct dm_space_map *sm)
+{
+ struct sm_disk *smd = container_of(sm, struct sm_disk, sm);
+
+ kfree(smd);
+}
+
+static int sm_disk_extend(struct dm_space_map *sm, dm_block_t extra_blocks)
+{
+ struct sm_disk *smd = container_of(sm, struct sm_disk, sm);
+
+ return sm_ll_extend(&smd->ll, extra_blocks);
+}
+
+static int sm_disk_get_nr_blocks(struct dm_space_map *sm, dm_block_t *count)
+{
+ struct sm_disk *smd = container_of(sm, struct sm_disk, sm);
+ *count = smd->old_ll.nr_blocks;
+
+ return 0;
+}
+
+static int sm_disk_get_nr_free(struct dm_space_map *sm, dm_block_t *count)
+{
+ struct sm_disk *smd = container_of(sm, struct sm_disk, sm);
+ *count = (smd->old_ll.nr_blocks - smd->old_ll.nr_allocated) - smd->nr_allocated_this_transaction;
+
+ return 0;
+}
+
+static int sm_disk_get_count(struct dm_space_map *sm, dm_block_t b,
+ uint32_t *result)
+{
+ struct sm_disk *smd = container_of(sm, struct sm_disk, sm);
+ return sm_ll_lookup(&smd->ll, b, result);
+}
+
+static int sm_disk_count_is_more_than_one(struct dm_space_map *sm, dm_block_t b,
+ int *result)
+{
+ int r;
+ uint32_t count;
+
+ r = sm_disk_get_count(sm, b, &count);
+ if (r)
+ return r;
+
+ *result = count > 1;
+
+ return 0;
+}
+
+static int sm_disk_set_count(struct dm_space_map *sm, dm_block_t b,
+ uint32_t count)
+{
+ int r;
+ uint32_t old_count;
+ enum allocation_event ev;
+ struct sm_disk *smd = container_of(sm, struct sm_disk, sm);
+
+ r = sm_ll_insert(&smd->ll, b, count, &ev);
+ if (!r) {
+ switch (ev) {
+ case SM_NONE:
+ break;
+
+ case SM_ALLOC:
+ /*
+ * This _must_ be free in the prior transaction
+ * otherwise we've lost atomicity.
+ */
+ smd->nr_allocated_this_transaction++;
+ break;
+
+ case SM_FREE:
+ /*
+ * It's only free if it's also free in the last
+ * transaction.
+ */
+ r = sm_ll_lookup(&smd->old_ll, b, &old_count);
+ if (r)
+ return r;
+
+ if (!old_count)
+ smd->nr_allocated_this_transaction--;
+ break;
+ }
+ }
+
+ return r;
+}
+
+static int sm_disk_inc_block(struct dm_space_map *sm, dm_block_t b)
+{
+ int r;
+ enum allocation_event ev;
+ struct sm_disk *smd = container_of(sm, struct sm_disk, sm);
+
+ r = sm_ll_inc(&smd->ll, b, &ev);
+ if (!r && (ev == SM_ALLOC))
+ /*
+ * This _must_ be free in the prior transaction
+ * otherwise we've lost atomicity.
+ */
+ smd->nr_allocated_this_transaction++;
+
+ return r;
+}
+
+static int sm_disk_dec_block(struct dm_space_map *sm, dm_block_t b)
+{
+ enum allocation_event ev;
+ struct sm_disk *smd = container_of(sm, struct sm_disk, sm);
+
+ return sm_ll_dec(&smd->ll, b, &ev);
+}
+
+static int sm_disk_new_block(struct dm_space_map *sm, dm_block_t *b)
+{
+ int r;
+ enum allocation_event ev;
+ struct sm_disk *smd = container_of(sm, struct sm_disk, sm);
+
+ /* FIXME: we should loop round a couple of times */
+ r = sm_ll_find_free_block(&smd->old_ll, smd->begin, smd->old_ll.nr_blocks, b);
+ if (r)
+ return r;
+
+ smd->begin = *b + 1;
+ r = sm_ll_inc(&smd->ll, *b, &ev);
+ if (!r) {
+ BUG_ON(ev != SM_ALLOC);
+ smd->nr_allocated_this_transaction++;
+ }
+
+ return r;
+}
+
+static int sm_disk_commit(struct dm_space_map *sm)
+{
+ int r;
+ dm_block_t nr_free;
+ struct sm_disk *smd = container_of(sm, struct sm_disk, sm);
+
+ r = sm_disk_get_nr_free(sm, &nr_free);
+ if (r)
+ return r;
+
+ r = sm_ll_commit(&smd->ll);
+ if (r)
+ return r;
+
+ memcpy(&smd->old_ll, &smd->ll, sizeof(smd->old_ll));
+ smd->begin = 0;
+ smd->nr_allocated_this_transaction = 0;
+
+ r = sm_disk_get_nr_free(sm, &nr_free);
+ if (r)
+ return r;
+
+ return 0;
+}
+
+static int sm_disk_root_size(struct dm_space_map *sm, size_t *result)
+{
+ *result = sizeof(struct disk_sm_root);
+
+ return 0;
+}
+
+static int sm_disk_copy_root(struct dm_space_map *sm, void *where_le, size_t max)
+{
+ struct sm_disk *smd = container_of(sm, struct sm_disk, sm);
+ struct disk_sm_root root_le;
+
+ root_le.nr_blocks = cpu_to_le64(smd->ll.nr_blocks);
+ root_le.nr_allocated = cpu_to_le64(smd->ll.nr_allocated);
+ root_le.bitmap_root = cpu_to_le64(smd->ll.bitmap_root);
+ root_le.ref_count_root = cpu_to_le64(smd->ll.ref_count_root);
+
+ if (max < sizeof(root_le))
+ return -ENOSPC;
+
+ memcpy(where_le, &root_le, sizeof(root_le));
+
+ return 0;
+}
+
+/*----------------------------------------------------------------*/
+
+static struct dm_space_map ops = {
+ .destroy = sm_disk_destroy,
+ .extend = sm_disk_extend,
+ .get_nr_blocks = sm_disk_get_nr_blocks,
+ .get_nr_free = sm_disk_get_nr_free,
+ .get_count = sm_disk_get_count,
+ .count_is_more_than_one = sm_disk_count_is_more_than_one,
+ .set_count = sm_disk_set_count,
+ .inc_block = sm_disk_inc_block,
+ .dec_block = sm_disk_dec_block,
+ .new_block = sm_disk_new_block,
+ .commit = sm_disk_commit,
+ .root_size = sm_disk_root_size,
+ .copy_root = sm_disk_copy_root,
+ .register_threshold_callback = NULL
+};
+
+struct dm_space_map *dm_sm_disk_create(struct dm_transaction_manager *tm,
+ dm_block_t nr_blocks)
+{
+ int r;
+ struct sm_disk *smd;
+
+ smd = kmalloc(sizeof(*smd), GFP_KERNEL);
+ if (!smd)
+ return ERR_PTR(-ENOMEM);
+
+ smd->begin = 0;
+ smd->nr_allocated_this_transaction = 0;
+ memcpy(&smd->sm, &ops, sizeof(smd->sm));
+
+ r = sm_ll_new_disk(&smd->ll, tm);
+ if (r)
+ goto bad;
+
+ r = sm_ll_extend(&smd->ll, nr_blocks);
+ if (r)
+ goto bad;
+
+ r = sm_disk_commit(&smd->sm);
+ if (r)
+ goto bad;
+
+ return &smd->sm;
+
+bad:
+ kfree(smd);
+ return ERR_PTR(r);
+}
+EXPORT_SYMBOL_GPL(dm_sm_disk_create);
+
+struct dm_space_map *dm_sm_disk_open(struct dm_transaction_manager *tm,
+ void *root_le, size_t len)
+{
+ int r;
+ struct sm_disk *smd;
+
+ smd = kmalloc(sizeof(*smd), GFP_KERNEL);
+ if (!smd)
+ return ERR_PTR(-ENOMEM);
+
+ smd->begin = 0;
+ smd->nr_allocated_this_transaction = 0;
+ memcpy(&smd->sm, &ops, sizeof(smd->sm));
+
+ r = sm_ll_open_disk(&smd->ll, tm, root_le, len);
+ if (r)
+ goto bad;
+
+ r = sm_disk_commit(&smd->sm);
+ if (r)
+ goto bad;
+
+ return &smd->sm;
+
+bad:
+ kfree(smd);
+ return ERR_PTR(r);
+}
+EXPORT_SYMBOL_GPL(dm_sm_disk_open);
+
+/*----------------------------------------------------------------*/
diff --git a/kernel/drivers/md/persistent-data/dm-space-map-disk.h b/kernel/drivers/md/persistent-data/dm-space-map-disk.h
new file mode 100644
index 000000000..447a0a9a2
--- /dev/null
+++ b/kernel/drivers/md/persistent-data/dm-space-map-disk.h
@@ -0,0 +1,25 @@
+/*
+ * Copyright (C) 2011 Red Hat, Inc.
+ *
+ * This file is released under the GPL.
+ */
+
+#ifndef _LINUX_DM_SPACE_MAP_DISK_H
+#define _LINUX_DM_SPACE_MAP_DISK_H
+
+#include "dm-block-manager.h"
+
+struct dm_space_map;
+struct dm_transaction_manager;
+
+/*
+ * Unfortunately we have to use two-phase construction due to the cycle
+ * between the tm and sm.
+ */
+struct dm_space_map *dm_sm_disk_create(struct dm_transaction_manager *tm,
+ dm_block_t nr_blocks);
+
+struct dm_space_map *dm_sm_disk_open(struct dm_transaction_manager *tm,
+ void *root, size_t len);
+
+#endif /* _LINUX_DM_SPACE_MAP_DISK_H */
diff --git a/kernel/drivers/md/persistent-data/dm-space-map-metadata.c b/kernel/drivers/md/persistent-data/dm-space-map-metadata.c
new file mode 100644
index 000000000..e8a904298
--- /dev/null
+++ b/kernel/drivers/md/persistent-data/dm-space-map-metadata.c
@@ -0,0 +1,798 @@
+/*
+ * Copyright (C) 2011 Red Hat, Inc.
+ *
+ * This file is released under the GPL.
+ */
+
+#include "dm-space-map.h"
+#include "dm-space-map-common.h"
+#include "dm-space-map-metadata.h"
+
+#include <linux/list.h>
+#include <linux/slab.h>
+#include <linux/device-mapper.h>
+
+#define DM_MSG_PREFIX "space map metadata"
+
+/*----------------------------------------------------------------*/
+
+/*
+ * An edge triggered threshold.
+ */
+struct threshold {
+ bool threshold_set;
+ bool value_set;
+ dm_block_t threshold;
+ dm_block_t current_value;
+ dm_sm_threshold_fn fn;
+ void *context;
+};
+
+static void threshold_init(struct threshold *t)
+{
+ t->threshold_set = false;
+ t->value_set = false;
+}
+
+static void set_threshold(struct threshold *t, dm_block_t value,
+ dm_sm_threshold_fn fn, void *context)
+{
+ t->threshold_set = true;
+ t->threshold = value;
+ t->fn = fn;
+ t->context = context;
+}
+
+static bool below_threshold(struct threshold *t, dm_block_t value)
+{
+ return t->threshold_set && value <= t->threshold;
+}
+
+static bool threshold_already_triggered(struct threshold *t)
+{
+ return t->value_set && below_threshold(t, t->current_value);
+}
+
+static void check_threshold(struct threshold *t, dm_block_t value)
+{
+ if (below_threshold(t, value) &&
+ !threshold_already_triggered(t))
+ t->fn(t->context);
+
+ t->value_set = true;
+ t->current_value = value;
+}
+
+/*----------------------------------------------------------------*/
+
+/*
+ * Space map interface.
+ *
+ * The low level disk format is written using the standard btree and
+ * transaction manager. This means that performing disk operations may
+ * cause us to recurse into the space map in order to allocate new blocks.
+ * For this reason we have a pool of pre-allocated blocks large enough to
+ * service any metadata_ll_disk operation.
+ */
+
+/*
+ * FIXME: we should calculate this based on the size of the device.
+ * Only the metadata space map needs this functionality.
+ */
+#define MAX_RECURSIVE_ALLOCATIONS 1024
+
+enum block_op_type {
+ BOP_INC,
+ BOP_DEC
+};
+
+struct block_op {
+ enum block_op_type type;
+ dm_block_t block;
+};
+
+struct bop_ring_buffer {
+ unsigned begin;
+ unsigned end;
+ struct block_op bops[MAX_RECURSIVE_ALLOCATIONS + 1];
+};
+
+static void brb_init(struct bop_ring_buffer *brb)
+{
+ brb->begin = 0;
+ brb->end = 0;
+}
+
+static bool brb_empty(struct bop_ring_buffer *brb)
+{
+ return brb->begin == brb->end;
+}
+
+static unsigned brb_next(struct bop_ring_buffer *brb, unsigned old)
+{
+ unsigned r = old + 1;
+ return (r >= (sizeof(brb->bops) / sizeof(*brb->bops))) ? 0 : r;
+}
+
+static int brb_push(struct bop_ring_buffer *brb,
+ enum block_op_type type, dm_block_t b)
+{
+ struct block_op *bop;
+ unsigned next = brb_next(brb, brb->end);
+
+ /*
+ * We don't allow the last bop to be filled, this way we can
+ * differentiate between full and empty.
+ */
+ if (next == brb->begin)
+ return -ENOMEM;
+
+ bop = brb->bops + brb->end;
+ bop->type = type;
+ bop->block = b;
+
+ brb->end = next;
+
+ return 0;
+}
+
+static int brb_pop(struct bop_ring_buffer *brb, struct block_op *result)
+{
+ struct block_op *bop;
+
+ if (brb_empty(brb))
+ return -ENODATA;
+
+ bop = brb->bops + brb->begin;
+ result->type = bop->type;
+ result->block = bop->block;
+
+ brb->begin = brb_next(brb, brb->begin);
+
+ return 0;
+}
+
+/*----------------------------------------------------------------*/
+
+struct sm_metadata {
+ struct dm_space_map sm;
+
+ struct ll_disk ll;
+ struct ll_disk old_ll;
+
+ dm_block_t begin;
+
+ unsigned recursion_count;
+ unsigned allocated_this_transaction;
+ struct bop_ring_buffer uncommitted;
+
+ struct threshold threshold;
+};
+
+static int add_bop(struct sm_metadata *smm, enum block_op_type type, dm_block_t b)
+{
+ int r = brb_push(&smm->uncommitted, type, b);
+
+ if (r) {
+ DMERR("too many recursive allocations");
+ return -ENOMEM;
+ }
+
+ return 0;
+}
+
+static int commit_bop(struct sm_metadata *smm, struct block_op *op)
+{
+ int r = 0;
+ enum allocation_event ev;
+
+ switch (op->type) {
+ case BOP_INC:
+ r = sm_ll_inc(&smm->ll, op->block, &ev);
+ break;
+
+ case BOP_DEC:
+ r = sm_ll_dec(&smm->ll, op->block, &ev);
+ break;
+ }
+
+ return r;
+}
+
+static void in(struct sm_metadata *smm)
+{
+ smm->recursion_count++;
+}
+
+static int out(struct sm_metadata *smm)
+{
+ int r = 0;
+
+ /*
+ * If we're not recursing then very bad things are happening.
+ */
+ if (!smm->recursion_count) {
+ DMERR("lost track of recursion depth");
+ return -ENOMEM;
+ }
+
+ if (smm->recursion_count == 1) {
+ while (!brb_empty(&smm->uncommitted)) {
+ struct block_op bop;
+
+ r = brb_pop(&smm->uncommitted, &bop);
+ if (r) {
+ DMERR("bug in bop ring buffer");
+ break;
+ }
+
+ r = commit_bop(smm, &bop);
+ if (r)
+ break;
+ }
+ }
+
+ smm->recursion_count--;
+
+ return r;
+}
+
+/*
+ * When using the out() function above, we often want to combine an error
+ * code for the operation run in the recursive context with that from
+ * out().
+ */
+static int combine_errors(int r1, int r2)
+{
+ return r1 ? r1 : r2;
+}
+
+static int recursing(struct sm_metadata *smm)
+{
+ return smm->recursion_count;
+}
+
+static void sm_metadata_destroy(struct dm_space_map *sm)
+{
+ struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
+
+ kfree(smm);
+}
+
+static int sm_metadata_get_nr_blocks(struct dm_space_map *sm, dm_block_t *count)
+{
+ struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
+
+ *count = smm->ll.nr_blocks;
+
+ return 0;
+}
+
+static int sm_metadata_get_nr_free(struct dm_space_map *sm, dm_block_t *count)
+{
+ struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
+
+ *count = smm->old_ll.nr_blocks - smm->old_ll.nr_allocated -
+ smm->allocated_this_transaction;
+
+ return 0;
+}
+
+static int sm_metadata_get_count(struct dm_space_map *sm, dm_block_t b,
+ uint32_t *result)
+{
+ int r;
+ unsigned i;
+ struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
+ unsigned adjustment = 0;
+
+ /*
+ * We may have some uncommitted adjustments to add. This list
+ * should always be really short.
+ */
+ for (i = smm->uncommitted.begin;
+ i != smm->uncommitted.end;
+ i = brb_next(&smm->uncommitted, i)) {
+ struct block_op *op = smm->uncommitted.bops + i;
+
+ if (op->block != b)
+ continue;
+
+ switch (op->type) {
+ case BOP_INC:
+ adjustment++;
+ break;
+
+ case BOP_DEC:
+ adjustment--;
+ break;
+ }
+ }
+
+ r = sm_ll_lookup(&smm->ll, b, result);
+ if (r)
+ return r;
+
+ *result += adjustment;
+
+ return 0;
+}
+
+static int sm_metadata_count_is_more_than_one(struct dm_space_map *sm,
+ dm_block_t b, int *result)
+{
+ int r, adjustment = 0;
+ unsigned i;
+ struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
+ uint32_t rc;
+
+ /*
+ * We may have some uncommitted adjustments to add. This list
+ * should always be really short.
+ */
+ for (i = smm->uncommitted.begin;
+ i != smm->uncommitted.end;
+ i = brb_next(&smm->uncommitted, i)) {
+
+ struct block_op *op = smm->uncommitted.bops + i;
+
+ if (op->block != b)
+ continue;
+
+ switch (op->type) {
+ case BOP_INC:
+ adjustment++;
+ break;
+
+ case BOP_DEC:
+ adjustment--;
+ break;
+ }
+ }
+
+ if (adjustment > 1) {
+ *result = 1;
+ return 0;
+ }
+
+ r = sm_ll_lookup_bitmap(&smm->ll, b, &rc);
+ if (r)
+ return r;
+
+ if (rc == 3)
+ /*
+ * We err on the side of caution, and always return true.
+ */
+ *result = 1;
+ else
+ *result = rc + adjustment > 1;
+
+ return 0;
+}
+
+static int sm_metadata_set_count(struct dm_space_map *sm, dm_block_t b,
+ uint32_t count)
+{
+ int r, r2;
+ enum allocation_event ev;
+ struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
+
+ if (smm->recursion_count) {
+ DMERR("cannot recurse set_count()");
+ return -EINVAL;
+ }
+
+ in(smm);
+ r = sm_ll_insert(&smm->ll, b, count, &ev);
+ r2 = out(smm);
+
+ return combine_errors(r, r2);
+}
+
+static int sm_metadata_inc_block(struct dm_space_map *sm, dm_block_t b)
+{
+ int r, r2 = 0;
+ enum allocation_event ev;
+ struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
+
+ if (recursing(smm))
+ r = add_bop(smm, BOP_INC, b);
+ else {
+ in(smm);
+ r = sm_ll_inc(&smm->ll, b, &ev);
+ r2 = out(smm);
+ }
+
+ return combine_errors(r, r2);
+}
+
+static int sm_metadata_dec_block(struct dm_space_map *sm, dm_block_t b)
+{
+ int r, r2 = 0;
+ enum allocation_event ev;
+ struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
+
+ if (recursing(smm))
+ r = add_bop(smm, BOP_DEC, b);
+ else {
+ in(smm);
+ r = sm_ll_dec(&smm->ll, b, &ev);
+ r2 = out(smm);
+ }
+
+ return combine_errors(r, r2);
+}
+
+static int sm_metadata_new_block_(struct dm_space_map *sm, dm_block_t *b)
+{
+ int r, r2 = 0;
+ enum allocation_event ev;
+ struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
+
+ r = sm_ll_find_free_block(&smm->old_ll, smm->begin, smm->old_ll.nr_blocks, b);
+ if (r)
+ return r;
+
+ smm->begin = *b + 1;
+
+ if (recursing(smm))
+ r = add_bop(smm, BOP_INC, *b);
+ else {
+ in(smm);
+ r = sm_ll_inc(&smm->ll, *b, &ev);
+ r2 = out(smm);
+ }
+
+ if (!r)
+ smm->allocated_this_transaction++;
+
+ return combine_errors(r, r2);
+}
+
+static int sm_metadata_new_block(struct dm_space_map *sm, dm_block_t *b)
+{
+ dm_block_t count;
+ struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
+
+ int r = sm_metadata_new_block_(sm, b);
+ if (r) {
+ DMERR_LIMIT("unable to allocate new metadata block");
+ return r;
+ }
+
+ r = sm_metadata_get_nr_free(sm, &count);
+ if (r) {
+ DMERR_LIMIT("couldn't get free block count");
+ return r;
+ }
+
+ check_threshold(&smm->threshold, count);
+
+ return r;
+}
+
+static int sm_metadata_commit(struct dm_space_map *sm)
+{
+ int r;
+ struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
+
+ r = sm_ll_commit(&smm->ll);
+ if (r)
+ return r;
+
+ memcpy(&smm->old_ll, &smm->ll, sizeof(smm->old_ll));
+ smm->begin = 0;
+ smm->allocated_this_transaction = 0;
+
+ return 0;
+}
+
+static int sm_metadata_register_threshold_callback(struct dm_space_map *sm,
+ dm_block_t threshold,
+ dm_sm_threshold_fn fn,
+ void *context)
+{
+ struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
+
+ set_threshold(&smm->threshold, threshold, fn, context);
+
+ return 0;
+}
+
+static int sm_metadata_root_size(struct dm_space_map *sm, size_t *result)
+{
+ *result = sizeof(struct disk_sm_root);
+
+ return 0;
+}
+
+static int sm_metadata_copy_root(struct dm_space_map *sm, void *where_le, size_t max)
+{
+ struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
+ struct disk_sm_root root_le;
+
+ root_le.nr_blocks = cpu_to_le64(smm->ll.nr_blocks);
+ root_le.nr_allocated = cpu_to_le64(smm->ll.nr_allocated);
+ root_le.bitmap_root = cpu_to_le64(smm->ll.bitmap_root);
+ root_le.ref_count_root = cpu_to_le64(smm->ll.ref_count_root);
+
+ if (max < sizeof(root_le))
+ return -ENOSPC;
+
+ memcpy(where_le, &root_le, sizeof(root_le));
+
+ return 0;
+}
+
+static int sm_metadata_extend(struct dm_space_map *sm, dm_block_t extra_blocks);
+
+static struct dm_space_map ops = {
+ .destroy = sm_metadata_destroy,
+ .extend = sm_metadata_extend,
+ .get_nr_blocks = sm_metadata_get_nr_blocks,
+ .get_nr_free = sm_metadata_get_nr_free,
+ .get_count = sm_metadata_get_count,
+ .count_is_more_than_one = sm_metadata_count_is_more_than_one,
+ .set_count = sm_metadata_set_count,
+ .inc_block = sm_metadata_inc_block,
+ .dec_block = sm_metadata_dec_block,
+ .new_block = sm_metadata_new_block,
+ .commit = sm_metadata_commit,
+ .root_size = sm_metadata_root_size,
+ .copy_root = sm_metadata_copy_root,
+ .register_threshold_callback = sm_metadata_register_threshold_callback
+};
+
+/*----------------------------------------------------------------*/
+
+/*
+ * When a new space map is created that manages its own space. We use
+ * this tiny bootstrap allocator.
+ */
+static void sm_bootstrap_destroy(struct dm_space_map *sm)
+{
+}
+
+static int sm_bootstrap_extend(struct dm_space_map *sm, dm_block_t extra_blocks)
+{
+ DMERR("bootstrap doesn't support extend");
+
+ return -EINVAL;
+}
+
+static int sm_bootstrap_get_nr_blocks(struct dm_space_map *sm, dm_block_t *count)
+{
+ struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
+
+ *count = smm->ll.nr_blocks;
+
+ return 0;
+}
+
+static int sm_bootstrap_get_nr_free(struct dm_space_map *sm, dm_block_t *count)
+{
+ struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
+
+ *count = smm->ll.nr_blocks - smm->begin;
+
+ return 0;
+}
+
+static int sm_bootstrap_get_count(struct dm_space_map *sm, dm_block_t b,
+ uint32_t *result)
+{
+ struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
+
+ *result = (b < smm->begin) ? 1 : 0;
+
+ return 0;
+}
+
+static int sm_bootstrap_count_is_more_than_one(struct dm_space_map *sm,
+ dm_block_t b, int *result)
+{
+ *result = 0;
+
+ return 0;
+}
+
+static int sm_bootstrap_set_count(struct dm_space_map *sm, dm_block_t b,
+ uint32_t count)
+{
+ DMERR("bootstrap doesn't support set_count");
+
+ return -EINVAL;
+}
+
+static int sm_bootstrap_new_block(struct dm_space_map *sm, dm_block_t *b)
+{
+ struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
+
+ /*
+ * We know the entire device is unused.
+ */
+ if (smm->begin == smm->ll.nr_blocks)
+ return -ENOSPC;
+
+ *b = smm->begin++;
+
+ return 0;
+}
+
+static int sm_bootstrap_inc_block(struct dm_space_map *sm, dm_block_t b)
+{
+ struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
+
+ return add_bop(smm, BOP_INC, b);
+}
+
+static int sm_bootstrap_dec_block(struct dm_space_map *sm, dm_block_t b)
+{
+ struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
+
+ return add_bop(smm, BOP_DEC, b);
+}
+
+static int sm_bootstrap_commit(struct dm_space_map *sm)
+{
+ return 0;
+}
+
+static int sm_bootstrap_root_size(struct dm_space_map *sm, size_t *result)
+{
+ DMERR("bootstrap doesn't support root_size");
+
+ return -EINVAL;
+}
+
+static int sm_bootstrap_copy_root(struct dm_space_map *sm, void *where,
+ size_t max)
+{
+ DMERR("bootstrap doesn't support copy_root");
+
+ return -EINVAL;
+}
+
+static struct dm_space_map bootstrap_ops = {
+ .destroy = sm_bootstrap_destroy,
+ .extend = sm_bootstrap_extend,
+ .get_nr_blocks = sm_bootstrap_get_nr_blocks,
+ .get_nr_free = sm_bootstrap_get_nr_free,
+ .get_count = sm_bootstrap_get_count,
+ .count_is_more_than_one = sm_bootstrap_count_is_more_than_one,
+ .set_count = sm_bootstrap_set_count,
+ .inc_block = sm_bootstrap_inc_block,
+ .dec_block = sm_bootstrap_dec_block,
+ .new_block = sm_bootstrap_new_block,
+ .commit = sm_bootstrap_commit,
+ .root_size = sm_bootstrap_root_size,
+ .copy_root = sm_bootstrap_copy_root,
+ .register_threshold_callback = NULL
+};
+
+/*----------------------------------------------------------------*/
+
+static int sm_metadata_extend(struct dm_space_map *sm, dm_block_t extra_blocks)
+{
+ int r, i;
+ enum allocation_event ev;
+ struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
+ dm_block_t old_len = smm->ll.nr_blocks;
+
+ /*
+ * Flick into a mode where all blocks get allocated in the new area.
+ */
+ smm->begin = old_len;
+ memcpy(sm, &bootstrap_ops, sizeof(*sm));
+
+ /*
+ * Extend.
+ */
+ r = sm_ll_extend(&smm->ll, extra_blocks);
+ if (r)
+ goto out;
+
+ /*
+ * We repeatedly increment then commit until the commit doesn't
+ * allocate any new blocks.
+ */
+ do {
+ for (i = old_len; !r && i < smm->begin; i++) {
+ r = sm_ll_inc(&smm->ll, i, &ev);
+ if (r)
+ goto out;
+ }
+ old_len = smm->begin;
+
+ r = sm_ll_commit(&smm->ll);
+ if (r)
+ goto out;
+
+ } while (old_len != smm->begin);
+
+out:
+ /*
+ * Switch back to normal behaviour.
+ */
+ memcpy(sm, &ops, sizeof(*sm));
+ return r;
+}
+
+/*----------------------------------------------------------------*/
+
+struct dm_space_map *dm_sm_metadata_init(void)
+{
+ struct sm_metadata *smm;
+
+ smm = kmalloc(sizeof(*smm), GFP_KERNEL);
+ if (!smm)
+ return ERR_PTR(-ENOMEM);
+
+ memcpy(&smm->sm, &ops, sizeof(smm->sm));
+
+ return &smm->sm;
+}
+
+int dm_sm_metadata_create(struct dm_space_map *sm,
+ struct dm_transaction_manager *tm,
+ dm_block_t nr_blocks,
+ dm_block_t superblock)
+{
+ int r;
+ dm_block_t i;
+ enum allocation_event ev;
+ struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
+
+ smm->begin = superblock + 1;
+ smm->recursion_count = 0;
+ smm->allocated_this_transaction = 0;
+ brb_init(&smm->uncommitted);
+ threshold_init(&smm->threshold);
+
+ memcpy(&smm->sm, &bootstrap_ops, sizeof(smm->sm));
+
+ r = sm_ll_new_metadata(&smm->ll, tm);
+ if (r)
+ return r;
+
+ if (nr_blocks > DM_SM_METADATA_MAX_BLOCKS)
+ nr_blocks = DM_SM_METADATA_MAX_BLOCKS;
+ r = sm_ll_extend(&smm->ll, nr_blocks);
+ if (r)
+ return r;
+
+ memcpy(&smm->sm, &ops, sizeof(smm->sm));
+
+ /*
+ * Now we need to update the newly created data structures with the
+ * allocated blocks that they were built from.
+ */
+ for (i = superblock; !r && i < smm->begin; i++)
+ r = sm_ll_inc(&smm->ll, i, &ev);
+
+ if (r)
+ return r;
+
+ return sm_metadata_commit(sm);
+}
+
+int dm_sm_metadata_open(struct dm_space_map *sm,
+ struct dm_transaction_manager *tm,
+ void *root_le, size_t len)
+{
+ int r;
+ struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
+
+ r = sm_ll_open_metadata(&smm->ll, tm, root_le, len);
+ if (r)
+ return r;
+
+ smm->begin = 0;
+ smm->recursion_count = 0;
+ smm->allocated_this_transaction = 0;
+ brb_init(&smm->uncommitted);
+ threshold_init(&smm->threshold);
+
+ memcpy(&smm->old_ll, &smm->ll, sizeof(smm->old_ll));
+ return 0;
+}
diff --git a/kernel/drivers/md/persistent-data/dm-space-map-metadata.h b/kernel/drivers/md/persistent-data/dm-space-map-metadata.h
new file mode 100644
index 000000000..64df92397
--- /dev/null
+++ b/kernel/drivers/md/persistent-data/dm-space-map-metadata.h
@@ -0,0 +1,44 @@
+/*
+ * Copyright (C) 2011 Red Hat, Inc.
+ *
+ * This file is released under the GPL.
+ */
+
+#ifndef DM_SPACE_MAP_METADATA_H
+#define DM_SPACE_MAP_METADATA_H
+
+#include "dm-transaction-manager.h"
+
+#define DM_SM_METADATA_BLOCK_SIZE (4096 >> SECTOR_SHIFT)
+
+/*
+ * The metadata device is currently limited in size.
+ *
+ * We have one block of index, which can hold 255 index entries. Each
+ * index entry contains allocation info about ~16k metadata blocks.
+ */
+#define DM_SM_METADATA_MAX_BLOCKS (255 * ((1 << 14) - 64))
+#define DM_SM_METADATA_MAX_SECTORS (DM_SM_METADATA_MAX_BLOCKS * DM_SM_METADATA_BLOCK_SIZE)
+
+/*
+ * Unfortunately we have to use two-phase construction due to the cycle
+ * between the tm and sm.
+ */
+struct dm_space_map *dm_sm_metadata_init(void);
+
+/*
+ * Create a fresh space map.
+ */
+int dm_sm_metadata_create(struct dm_space_map *sm,
+ struct dm_transaction_manager *tm,
+ dm_block_t nr_blocks,
+ dm_block_t superblock);
+
+/*
+ * Open from a previously-recorded root.
+ */
+int dm_sm_metadata_open(struct dm_space_map *sm,
+ struct dm_transaction_manager *tm,
+ void *root_le, size_t len);
+
+#endif /* DM_SPACE_MAP_METADATA_H */
diff --git a/kernel/drivers/md/persistent-data/dm-space-map.h b/kernel/drivers/md/persistent-data/dm-space-map.h
new file mode 100644
index 000000000..3e6d1153b
--- /dev/null
+++ b/kernel/drivers/md/persistent-data/dm-space-map.h
@@ -0,0 +1,157 @@
+/*
+ * Copyright (C) 2011 Red Hat, Inc.
+ *
+ * This file is released under the GPL.
+ */
+
+#ifndef _LINUX_DM_SPACE_MAP_H
+#define _LINUX_DM_SPACE_MAP_H
+
+#include "dm-block-manager.h"
+
+typedef void (*dm_sm_threshold_fn)(void *context);
+
+/*
+ * struct dm_space_map keeps a record of how many times each block in a device
+ * is referenced. It needs to be fixed on disk as part of the transaction.
+ */
+struct dm_space_map {
+ void (*destroy)(struct dm_space_map *sm);
+
+ /*
+ * You must commit before allocating the newly added space.
+ */
+ int (*extend)(struct dm_space_map *sm, dm_block_t extra_blocks);
+
+ /*
+ * Extensions do not appear in this count until after commit has
+ * been called.
+ */
+ int (*get_nr_blocks)(struct dm_space_map *sm, dm_block_t *count);
+
+ /*
+ * Space maps must never allocate a block from the previous
+ * transaction, in case we need to rollback. This complicates the
+ * semantics of get_nr_free(), it should return the number of blocks
+ * that are available for allocation _now_. For instance you may
+ * have blocks with a zero reference count that will not be
+ * available for allocation until after the next commit.
+ */
+ int (*get_nr_free)(struct dm_space_map *sm, dm_block_t *count);
+
+ int (*get_count)(struct dm_space_map *sm, dm_block_t b, uint32_t *result);
+ int (*count_is_more_than_one)(struct dm_space_map *sm, dm_block_t b,
+ int *result);
+ int (*set_count)(struct dm_space_map *sm, dm_block_t b, uint32_t count);
+
+ int (*commit)(struct dm_space_map *sm);
+
+ int (*inc_block)(struct dm_space_map *sm, dm_block_t b);
+ int (*dec_block)(struct dm_space_map *sm, dm_block_t b);
+
+ /*
+ * new_block will increment the returned block.
+ */
+ int (*new_block)(struct dm_space_map *sm, dm_block_t *b);
+
+ /*
+ * The root contains all the information needed to fix the space map.
+ * Generally this info is small, so squirrel it away in a disk block
+ * along with other info.
+ */
+ int (*root_size)(struct dm_space_map *sm, size_t *result);
+ int (*copy_root)(struct dm_space_map *sm, void *copy_to_here_le, size_t len);
+
+ /*
+ * You can register one threshold callback which is edge-triggered
+ * when the free space in the space map drops below the threshold.
+ */
+ int (*register_threshold_callback)(struct dm_space_map *sm,
+ dm_block_t threshold,
+ dm_sm_threshold_fn fn,
+ void *context);
+};
+
+/*----------------------------------------------------------------*/
+
+static inline void dm_sm_destroy(struct dm_space_map *sm)
+{
+ sm->destroy(sm);
+}
+
+static inline int dm_sm_extend(struct dm_space_map *sm, dm_block_t extra_blocks)
+{
+ return sm->extend(sm, extra_blocks);
+}
+
+static inline int dm_sm_get_nr_blocks(struct dm_space_map *sm, dm_block_t *count)
+{
+ return sm->get_nr_blocks(sm, count);
+}
+
+static inline int dm_sm_get_nr_free(struct dm_space_map *sm, dm_block_t *count)
+{
+ return sm->get_nr_free(sm, count);
+}
+
+static inline int dm_sm_get_count(struct dm_space_map *sm, dm_block_t b,
+ uint32_t *result)
+{
+ return sm->get_count(sm, b, result);
+}
+
+static inline int dm_sm_count_is_more_than_one(struct dm_space_map *sm,
+ dm_block_t b, int *result)
+{
+ return sm->count_is_more_than_one(sm, b, result);
+}
+
+static inline int dm_sm_set_count(struct dm_space_map *sm, dm_block_t b,
+ uint32_t count)
+{
+ return sm->set_count(sm, b, count);
+}
+
+static inline int dm_sm_commit(struct dm_space_map *sm)
+{
+ return sm->commit(sm);
+}
+
+static inline int dm_sm_inc_block(struct dm_space_map *sm, dm_block_t b)
+{
+ return sm->inc_block(sm, b);
+}
+
+static inline int dm_sm_dec_block(struct dm_space_map *sm, dm_block_t b)
+{
+ return sm->dec_block(sm, b);
+}
+
+static inline int dm_sm_new_block(struct dm_space_map *sm, dm_block_t *b)
+{
+ return sm->new_block(sm, b);
+}
+
+static inline int dm_sm_root_size(struct dm_space_map *sm, size_t *result)
+{
+ return sm->root_size(sm, result);
+}
+
+static inline int dm_sm_copy_root(struct dm_space_map *sm, void *copy_to_here_le, size_t len)
+{
+ return sm->copy_root(sm, copy_to_here_le, len);
+}
+
+static inline int dm_sm_register_threshold_callback(struct dm_space_map *sm,
+ dm_block_t threshold,
+ dm_sm_threshold_fn fn,
+ void *context)
+{
+ if (sm->register_threshold_callback)
+ return sm->register_threshold_callback(sm, threshold, fn, context);
+
+ return -EINVAL;
+}
+
+
+#endif /* _LINUX_DM_SPACE_MAP_H */
diff --git a/kernel/drivers/md/persistent-data/dm-transaction-manager.c b/kernel/drivers/md/persistent-data/dm-transaction-manager.c
new file mode 100644
index 000000000..9cb797d80
--- /dev/null
+++ b/kernel/drivers/md/persistent-data/dm-transaction-manager.c
@@ -0,0 +1,455 @@
+/*
+ * Copyright (C) 2011 Red Hat, Inc.
+ *
+ * This file is released under the GPL.
+ */
+#include "dm-transaction-manager.h"
+#include "dm-space-map.h"
+#include "dm-space-map-disk.h"
+#include "dm-space-map-metadata.h"
+#include "dm-persistent-data-internal.h"
+
+#include <linux/export.h>
+#include <linux/mutex.h>
+#include <linux/hash.h>
+#include <linux/slab.h>
+#include <linux/device-mapper.h>
+
+#define DM_MSG_PREFIX "transaction manager"
+
+/*----------------------------------------------------------------*/
+
+#define PREFETCH_SIZE 128
+#define PREFETCH_BITS 7
+#define PREFETCH_SENTINEL ((dm_block_t) -1ULL)
+
+struct prefetch_set {
+ struct mutex lock;
+ dm_block_t blocks[PREFETCH_SIZE];
+};
+
+static unsigned prefetch_hash(dm_block_t b)
+{
+ return hash_64(b, PREFETCH_BITS);
+}
+
+static void prefetch_wipe(struct prefetch_set *p)
+{
+ unsigned i;
+ for (i = 0; i < PREFETCH_SIZE; i++)
+ p->blocks[i] = PREFETCH_SENTINEL;
+}
+
+static void prefetch_init(struct prefetch_set *p)
+{
+ mutex_init(&p->lock);
+ prefetch_wipe(p);
+}
+
+static void prefetch_add(struct prefetch_set *p, dm_block_t b)
+{
+ unsigned h = prefetch_hash(b);
+
+ mutex_lock(&p->lock);
+ if (p->blocks[h] == PREFETCH_SENTINEL)
+ p->blocks[h] = b;
+
+ mutex_unlock(&p->lock);
+}
+
+static void prefetch_issue(struct prefetch_set *p, struct dm_block_manager *bm)
+{
+ unsigned i;
+
+ mutex_lock(&p->lock);
+
+ for (i = 0; i < PREFETCH_SIZE; i++)
+ if (p->blocks[i] != PREFETCH_SENTINEL) {
+ dm_bm_prefetch(bm, p->blocks[i]);
+ p->blocks[i] = PREFETCH_SENTINEL;
+ }
+
+ mutex_unlock(&p->lock);
+}
+
+/*----------------------------------------------------------------*/
+
+struct shadow_info {
+ struct hlist_node hlist;
+ dm_block_t where;
+};
+
+/*
+ * It would be nice if we scaled with the size of transaction.
+ */
+#define DM_HASH_SIZE 256
+#define DM_HASH_MASK (DM_HASH_SIZE - 1)
+
+struct dm_transaction_manager {
+ int is_clone;
+ struct dm_transaction_manager *real;
+
+ struct dm_block_manager *bm;
+ struct dm_space_map *sm;
+
+ spinlock_t lock;
+ struct hlist_head buckets[DM_HASH_SIZE];
+
+ struct prefetch_set prefetches;
+};
+
+/*----------------------------------------------------------------*/
+
+static int is_shadow(struct dm_transaction_manager *tm, dm_block_t b)
+{
+ int r = 0;
+ unsigned bucket = dm_hash_block(b, DM_HASH_MASK);
+ struct shadow_info *si;
+
+ spin_lock(&tm->lock);
+ hlist_for_each_entry(si, tm->buckets + bucket, hlist)
+ if (si->where == b) {
+ r = 1;
+ break;
+ }
+ spin_unlock(&tm->lock);
+
+ return r;
+}
+
+/*
+ * This can silently fail if there's no memory. We're ok with this since
+ * creating redundant shadows causes no harm.
+ */
+static void insert_shadow(struct dm_transaction_manager *tm, dm_block_t b)
+{
+ unsigned bucket;
+ struct shadow_info *si;
+
+ si = kmalloc(sizeof(*si), GFP_NOIO);
+ if (si) {
+ si->where = b;
+ bucket = dm_hash_block(b, DM_HASH_MASK);
+ spin_lock(&tm->lock);
+ hlist_add_head(&si->hlist, tm->buckets + bucket);
+ spin_unlock(&tm->lock);
+ }
+}
+
+static void wipe_shadow_table(struct dm_transaction_manager *tm)
+{
+ struct shadow_info *si;
+ struct hlist_node *tmp;
+ struct hlist_head *bucket;
+ int i;
+
+ spin_lock(&tm->lock);
+ for (i = 0; i < DM_HASH_SIZE; i++) {
+ bucket = tm->buckets + i;
+ hlist_for_each_entry_safe(si, tmp, bucket, hlist)
+ kfree(si);
+
+ INIT_HLIST_HEAD(bucket);
+ }
+
+ spin_unlock(&tm->lock);
+}
+
+/*----------------------------------------------------------------*/
+
+static struct dm_transaction_manager *dm_tm_create(struct dm_block_manager *bm,
+ struct dm_space_map *sm)
+{
+ int i;
+ struct dm_transaction_manager *tm;
+
+ tm = kmalloc(sizeof(*tm), GFP_KERNEL);
+ if (!tm)
+ return ERR_PTR(-ENOMEM);
+
+ tm->is_clone = 0;
+ tm->real = NULL;
+ tm->bm = bm;
+ tm->sm = sm;
+
+ spin_lock_init(&tm->lock);
+ for (i = 0; i < DM_HASH_SIZE; i++)
+ INIT_HLIST_HEAD(tm->buckets + i);
+
+ prefetch_init(&tm->prefetches);
+
+ return tm;
+}
+
+struct dm_transaction_manager *dm_tm_create_non_blocking_clone(struct dm_transaction_manager *real)
+{
+ struct dm_transaction_manager *tm;
+
+ tm = kmalloc(sizeof(*tm), GFP_KERNEL);
+ if (tm) {
+ tm->is_clone = 1;
+ tm->real = real;
+ }
+
+ return tm;
+}
+EXPORT_SYMBOL_GPL(dm_tm_create_non_blocking_clone);
+
+void dm_tm_destroy(struct dm_transaction_manager *tm)
+{
+ if (!tm->is_clone)
+ wipe_shadow_table(tm);
+
+ kfree(tm);
+}
+EXPORT_SYMBOL_GPL(dm_tm_destroy);
+
+int dm_tm_pre_commit(struct dm_transaction_manager *tm)
+{
+ int r;
+
+ if (tm->is_clone)
+ return -EWOULDBLOCK;
+
+ r = dm_sm_commit(tm->sm);
+ if (r < 0)
+ return r;
+
+ return dm_bm_flush(tm->bm);
+}
+EXPORT_SYMBOL_GPL(dm_tm_pre_commit);
+
+int dm_tm_commit(struct dm_transaction_manager *tm, struct dm_block *root)
+{
+ if (tm->is_clone)
+ return -EWOULDBLOCK;
+
+ wipe_shadow_table(tm);
+ dm_bm_unlock(root);
+
+ return dm_bm_flush(tm->bm);
+}
+EXPORT_SYMBOL_GPL(dm_tm_commit);
+
+int dm_tm_new_block(struct dm_transaction_manager *tm,
+ struct dm_block_validator *v,
+ struct dm_block **result)
+{
+ int r;
+ dm_block_t new_block;
+
+ if (tm->is_clone)
+ return -EWOULDBLOCK;
+
+ r = dm_sm_new_block(tm->sm, &new_block);
+ if (r < 0)
+ return r;
+
+ r = dm_bm_write_lock_zero(tm->bm, new_block, v, result);
+ if (r < 0) {
+ dm_sm_dec_block(tm->sm, new_block);
+ return r;
+ }
+
+ /*
+ * New blocks count as shadows in that they don't need to be
+ * shadowed again.
+ */
+ insert_shadow(tm, new_block);
+
+ return 0;
+}
+
+static int __shadow_block(struct dm_transaction_manager *tm, dm_block_t orig,
+ struct dm_block_validator *v,
+ struct dm_block **result)
+{
+ int r;
+ dm_block_t new;
+ struct dm_block *orig_block;
+
+ r = dm_sm_new_block(tm->sm, &new);
+ if (r < 0)
+ return r;
+
+ r = dm_sm_dec_block(tm->sm, orig);
+ if (r < 0)
+ return r;
+
+ r = dm_bm_read_lock(tm->bm, orig, v, &orig_block);
+ if (r < 0)
+ return r;
+
+ /*
+ * It would be tempting to use dm_bm_unlock_move here, but some
+ * code, such as the space maps, keeps using the old data structures
+ * secure in the knowledge they won't be changed until the next
+ * transaction. Using unlock_move would force a synchronous read
+ * since the old block would no longer be in the cache.
+ */
+ r = dm_bm_write_lock_zero(tm->bm, new, v, result);
+ if (r) {
+ dm_bm_unlock(orig_block);
+ return r;
+ }
+
+ memcpy(dm_block_data(*result), dm_block_data(orig_block),
+ dm_bm_block_size(tm->bm));
+
+ dm_bm_unlock(orig_block);
+ return r;
+}
+
+int dm_tm_shadow_block(struct dm_transaction_manager *tm, dm_block_t orig,
+ struct dm_block_validator *v, struct dm_block **result,
+ int *inc_children)
+{
+ int r;
+
+ if (tm->is_clone)
+ return -EWOULDBLOCK;
+
+ r = dm_sm_count_is_more_than_one(tm->sm, orig, inc_children);
+ if (r < 0)
+ return r;
+
+ if (is_shadow(tm, orig) && !*inc_children)
+ return dm_bm_write_lock(tm->bm, orig, v, result);
+
+ r = __shadow_block(tm, orig, v, result);
+ if (r < 0)
+ return r;
+ insert_shadow(tm, dm_block_location(*result));
+
+ return r;
+}
+EXPORT_SYMBOL_GPL(dm_tm_shadow_block);
+
+int dm_tm_read_lock(struct dm_transaction_manager *tm, dm_block_t b,
+ struct dm_block_validator *v,
+ struct dm_block **blk)
+{
+ if (tm->is_clone) {
+ int r = dm_bm_read_try_lock(tm->real->bm, b, v, blk);
+
+ if (r == -EWOULDBLOCK)
+ prefetch_add(&tm->real->prefetches, b);
+
+ return r;
+ }
+
+ return dm_bm_read_lock(tm->bm, b, v, blk);
+}
+EXPORT_SYMBOL_GPL(dm_tm_read_lock);
+
+int dm_tm_unlock(struct dm_transaction_manager *tm, struct dm_block *b)
+{
+ return dm_bm_unlock(b);
+}
+EXPORT_SYMBOL_GPL(dm_tm_unlock);
+
+void dm_tm_inc(struct dm_transaction_manager *tm, dm_block_t b)
+{
+ /*
+ * The non-blocking clone doesn't support this.
+ */
+ BUG_ON(tm->is_clone);
+
+ dm_sm_inc_block(tm->sm, b);
+}
+EXPORT_SYMBOL_GPL(dm_tm_inc);
+
+void dm_tm_dec(struct dm_transaction_manager *tm, dm_block_t b)
+{
+ /*
+ * The non-blocking clone doesn't support this.
+ */
+ BUG_ON(tm->is_clone);
+
+ dm_sm_dec_block(tm->sm, b);
+}
+EXPORT_SYMBOL_GPL(dm_tm_dec);
+
+int dm_tm_ref(struct dm_transaction_manager *tm, dm_block_t b,
+ uint32_t *result)
+{
+ if (tm->is_clone)
+ return -EWOULDBLOCK;
+
+ return dm_sm_get_count(tm->sm, b, result);
+}
+
+struct dm_block_manager *dm_tm_get_bm(struct dm_transaction_manager *tm)
+{
+ return tm->bm;
+}
+
+void dm_tm_issue_prefetches(struct dm_transaction_manager *tm)
+{
+ prefetch_issue(&tm->prefetches, tm->bm);
+}
+EXPORT_SYMBOL_GPL(dm_tm_issue_prefetches);
+
+/*----------------------------------------------------------------*/
+
+static int dm_tm_create_internal(struct dm_block_manager *bm,
+ dm_block_t sb_location,
+ struct dm_transaction_manager **tm,
+ struct dm_space_map **sm,
+ int create,
+ void *sm_root, size_t sm_len)
+{
+ int r;
+
+ *sm = dm_sm_metadata_init();
+ if (IS_ERR(*sm))
+ return PTR_ERR(*sm);
+
+ *tm = dm_tm_create(bm, *sm);
+ if (IS_ERR(*tm)) {
+ dm_sm_destroy(*sm);
+ return PTR_ERR(*tm);
+ }
+
+ if (create) {
+ r = dm_sm_metadata_create(*sm, *tm, dm_bm_nr_blocks(bm),
+ sb_location);
+ if (r) {
+ DMERR("couldn't create metadata space map");
+ goto bad;
+ }
+
+ } else {
+ r = dm_sm_metadata_open(*sm, *tm, sm_root, sm_len);
+ if (r) {
+ DMERR("couldn't open metadata space map");
+ goto bad;
+ }
+ }
+
+ return 0;
+
+bad:
+ dm_tm_destroy(*tm);
+ dm_sm_destroy(*sm);
+ return r;
+}
+
+int dm_tm_create_with_sm(struct dm_block_manager *bm, dm_block_t sb_location,
+ struct dm_transaction_manager **tm,
+ struct dm_space_map **sm)
+{
+ return dm_tm_create_internal(bm, sb_location, tm, sm, 1, NULL, 0);
+}
+EXPORT_SYMBOL_GPL(dm_tm_create_with_sm);
+
+int dm_tm_open_with_sm(struct dm_block_manager *bm, dm_block_t sb_location,
+ void *sm_root, size_t root_len,
+ struct dm_transaction_manager **tm,
+ struct dm_space_map **sm)
+{
+ return dm_tm_create_internal(bm, sb_location, tm, sm, 0, sm_root, root_len);
+}
+EXPORT_SYMBOL_GPL(dm_tm_open_with_sm);
+
+/*----------------------------------------------------------------*/
diff --git a/kernel/drivers/md/persistent-data/dm-transaction-manager.h b/kernel/drivers/md/persistent-data/dm-transaction-manager.h
new file mode 100644
index 000000000..2e0d4d66f
--- /dev/null
+++ b/kernel/drivers/md/persistent-data/dm-transaction-manager.h
@@ -0,0 +1,137 @@
+/*
+ * Copyright (C) 2011 Red Hat, Inc.
+ *
+ * This file is released under the GPL.
+ */
+
+#ifndef _LINUX_DM_TRANSACTION_MANAGER_H
+#define _LINUX_DM_TRANSACTION_MANAGER_H
+
+#include "dm-block-manager.h"
+
+struct dm_transaction_manager;
+struct dm_space_map;
+
+/*----------------------------------------------------------------*/
+
+/*
+ * This manages the scope of a transaction. It also enforces immutability
+ * of the on-disk data structures by limiting access to writeable blocks.
+ *
+ * Clients should not fiddle with the block manager directly.
+ */
+
+void dm_tm_destroy(struct dm_transaction_manager *tm);
+
+/*
+ * The non-blocking version of a transaction manager is intended for use in
+ * fast path code that needs to do lookups e.g. a dm mapping function.
+ * You create the non-blocking variant from a normal tm. The interface is
+ * the same, except that most functions will just return -EWOULDBLOCK.
+ * Methods that return void yet may block should not be called on a clone
+ * viz. dm_tm_inc, dm_tm_dec. Call dm_tm_destroy() as you would with a normal
+ * tm when you've finished with it. You may not destroy the original prior
+ * to clones.
+ */
+struct dm_transaction_manager *dm_tm_create_non_blocking_clone(struct dm_transaction_manager *real);
+
+/*
+ * We use a 2-phase commit here.
+ *
+ * i) Make all changes for the transaction *except* for the superblock.
+ * Then call dm_tm_pre_commit() to flush them to disk.
+ *
+ * ii) Lock your superblock. Update. Then call dm_tm_commit() which will
+ * unlock the superblock and flush it. No other blocks should be updated
+ * during this period. Care should be taken to never unlock a partially
+ * updated superblock; perform any operations that could fail *before* you
+ * take the superblock lock.
+ */
+int dm_tm_pre_commit(struct dm_transaction_manager *tm);
+int dm_tm_commit(struct dm_transaction_manager *tm, struct dm_block *superblock);
+
+/*
+ * These methods are the only way to get hold of a writeable block.
+ */
+
+/*
+ * dm_tm_new_block() is pretty self-explanatory. Make sure you do actually
+ * write to the whole of @data before you unlock, otherwise you could get
+ * a data leak. (The other option is for tm_new_block() to zero new blocks
+ * before handing them out, which will be redundant in most, if not all,
+ * cases).
+ * Zeroes the new block and returns with write lock held.
+ */
+int dm_tm_new_block(struct dm_transaction_manager *tm,
+ struct dm_block_validator *v,
+ struct dm_block **result);
+
+/*
+ * dm_tm_shadow_block() allocates a new block and copies the data from @orig
+ * to it. It then decrements the reference count on original block. Use
+ * this to update the contents of a block in a data structure, don't
+ * confuse this with a clone - you shouldn't access the orig block after
+ * this operation. Because the tm knows the scope of the transaction it
+ * can optimise requests for a shadow of a shadow to a no-op. Don't forget
+ * to unlock when you've finished with the shadow.
+ *
+ * The @inc_children flag is used to tell the caller whether it needs to
+ * adjust reference counts for children. (Data in the block may refer to
+ * other blocks.)
+ *
+ * Shadowing implicitly drops a reference on @orig so you must not have
+ * it locked when you call this.
+ */
+int dm_tm_shadow_block(struct dm_transaction_manager *tm, dm_block_t orig,
+ struct dm_block_validator *v,
+ struct dm_block **result, int *inc_children);
+
+/*
+ * Read access. You can lock any block you want. If there's a write lock
+ * on it outstanding then it'll block.
+ */
+int dm_tm_read_lock(struct dm_transaction_manager *tm, dm_block_t b,
+ struct dm_block_validator *v,
+ struct dm_block **result);
+
+int dm_tm_unlock(struct dm_transaction_manager *tm, struct dm_block *b);
+
+/*
+ * Functions for altering the reference count of a block directly.
+ */
+void dm_tm_inc(struct dm_transaction_manager *tm, dm_block_t b);
+
+void dm_tm_dec(struct dm_transaction_manager *tm, dm_block_t b);
+
+int dm_tm_ref(struct dm_transaction_manager *tm, dm_block_t b,
+ uint32_t *result);
+
+struct dm_block_manager *dm_tm_get_bm(struct dm_transaction_manager *tm);
+
+/*
+ * If you're using a non-blocking clone the tm will build up a list of
+ * requested blocks that weren't in core. This call will request those
+ * blocks to be prefetched.
+ */
+void dm_tm_issue_prefetches(struct dm_transaction_manager *tm);
+
+/*
+ * A little utility that ties the knot by producing a transaction manager
+ * that has a space map managed by the transaction manager...
+ *
+ * Returns a tm that has an open transaction to write the new disk sm.
+ * Caller should store the new sm root and commit.
+ *
+ * The superblock location is passed so the metadata space map knows it
+ * shouldn't be used.
+ */
+int dm_tm_create_with_sm(struct dm_block_manager *bm, dm_block_t sb_location,
+ struct dm_transaction_manager **tm,
+ struct dm_space_map **sm);
+
+int dm_tm_open_with_sm(struct dm_block_manager *bm, dm_block_t sb_location,
+ void *sm_root, size_t root_len,
+ struct dm_transaction_manager **tm,
+ struct dm_space_map **sm);
+
+#endif /* _LINUX_DM_TRANSACTION_MANAGER_H */