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819 lines
20 KiB
819 lines
20 KiB
/*
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* Copyright (C) 2012 Red Hat, Inc.
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*
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* This file is released under the GPL.
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*/
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#include "dm-array.h"
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#include "dm-space-map.h"
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#include "dm-transaction-manager.h"
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#include <linux/export.h>
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#include <linux/device-mapper.h>
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#define DM_MSG_PREFIX "array"
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/*----------------------------------------------------------------*/
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/*
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* The array is implemented as a fully populated btree, which points to
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* blocks that contain the packed values. This is more space efficient
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* than just using a btree since we don't store 1 key per value.
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*/
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struct array_block {
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__le32 csum;
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__le32 max_entries;
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__le32 nr_entries;
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__le32 value_size;
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__le64 blocknr; /* Block this node is supposed to live in. */
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} __packed;
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/*----------------------------------------------------------------*/
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/*
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* Validator methods. As usual we calculate a checksum, and also write the
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* block location into the header (paranoia about ssds remapping areas by
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* mistake).
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*/
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#define CSUM_XOR 595846735
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static void array_block_prepare_for_write(struct dm_block_validator *v,
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struct dm_block *b,
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size_t size_of_block)
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{
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struct array_block *bh_le = dm_block_data(b);
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bh_le->blocknr = cpu_to_le64(dm_block_location(b));
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bh_le->csum = cpu_to_le32(dm_bm_checksum(&bh_le->max_entries,
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size_of_block - sizeof(__le32),
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CSUM_XOR));
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}
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static int array_block_check(struct dm_block_validator *v,
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struct dm_block *b,
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size_t size_of_block)
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{
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struct array_block *bh_le = dm_block_data(b);
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__le32 csum_disk;
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if (dm_block_location(b) != le64_to_cpu(bh_le->blocknr)) {
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DMERR_LIMIT("array_block_check failed: blocknr %llu != wanted %llu",
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(unsigned long long) le64_to_cpu(bh_le->blocknr),
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(unsigned long long) dm_block_location(b));
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return -ENOTBLK;
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}
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csum_disk = cpu_to_le32(dm_bm_checksum(&bh_le->max_entries,
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size_of_block - sizeof(__le32),
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CSUM_XOR));
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if (csum_disk != bh_le->csum) {
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DMERR_LIMIT("array_block_check failed: csum %u != wanted %u",
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(unsigned) le32_to_cpu(csum_disk),
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(unsigned) le32_to_cpu(bh_le->csum));
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return -EILSEQ;
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}
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return 0;
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}
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static struct dm_block_validator array_validator = {
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.name = "array",
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.prepare_for_write = array_block_prepare_for_write,
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.check = array_block_check
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};
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/*----------------------------------------------------------------*/
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/*
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* Functions for manipulating the array blocks.
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*/
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/*
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* Returns a pointer to a value within an array block.
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*
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* index - The index into _this_ specific block.
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*/
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static void *element_at(struct dm_array_info *info, struct array_block *ab,
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unsigned index)
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{
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unsigned char *entry = (unsigned char *) (ab + 1);
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entry += index * info->value_type.size;
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return entry;
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}
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/*
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* Utility function that calls one of the value_type methods on every value
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* in an array block.
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*/
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static void on_entries(struct dm_array_info *info, struct array_block *ab,
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void (*fn)(void *, const void *))
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{
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unsigned i, nr_entries = le32_to_cpu(ab->nr_entries);
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for (i = 0; i < nr_entries; i++)
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fn(info->value_type.context, element_at(info, ab, i));
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}
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/*
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* Increment every value in an array block.
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*/
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static void inc_ablock_entries(struct dm_array_info *info, struct array_block *ab)
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{
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struct dm_btree_value_type *vt = &info->value_type;
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if (vt->inc)
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on_entries(info, ab, vt->inc);
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}
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/*
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* Decrement every value in an array block.
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*/
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static void dec_ablock_entries(struct dm_array_info *info, struct array_block *ab)
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{
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struct dm_btree_value_type *vt = &info->value_type;
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if (vt->dec)
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on_entries(info, ab, vt->dec);
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}
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/*
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* Each array block can hold this many values.
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*/
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static uint32_t calc_max_entries(size_t value_size, size_t size_of_block)
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{
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return (size_of_block - sizeof(struct array_block)) / value_size;
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}
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/*
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* Allocate a new array block. The caller will need to unlock block.
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*/
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static int alloc_ablock(struct dm_array_info *info, size_t size_of_block,
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uint32_t max_entries,
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struct dm_block **block, struct array_block **ab)
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{
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int r;
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r = dm_tm_new_block(info->btree_info.tm, &array_validator, block);
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if (r)
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return r;
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(*ab) = dm_block_data(*block);
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(*ab)->max_entries = cpu_to_le32(max_entries);
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(*ab)->nr_entries = cpu_to_le32(0);
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(*ab)->value_size = cpu_to_le32(info->value_type.size);
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return 0;
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}
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/*
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* Pad an array block out with a particular value. Every instance will
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* cause an increment of the value_type. new_nr must always be more than
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* the current number of entries.
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*/
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static void fill_ablock(struct dm_array_info *info, struct array_block *ab,
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const void *value, unsigned new_nr)
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{
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unsigned i;
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uint32_t nr_entries;
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struct dm_btree_value_type *vt = &info->value_type;
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BUG_ON(new_nr > le32_to_cpu(ab->max_entries));
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BUG_ON(new_nr < le32_to_cpu(ab->nr_entries));
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nr_entries = le32_to_cpu(ab->nr_entries);
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for (i = nr_entries; i < new_nr; i++) {
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if (vt->inc)
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vt->inc(vt->context, value);
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memcpy(element_at(info, ab, i), value, vt->size);
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}
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ab->nr_entries = cpu_to_le32(new_nr);
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}
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/*
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* Remove some entries from the back of an array block. Every value
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* removed will be decremented. new_nr must be <= the current number of
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* entries.
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*/
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static void trim_ablock(struct dm_array_info *info, struct array_block *ab,
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unsigned new_nr)
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{
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unsigned i;
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uint32_t nr_entries;
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struct dm_btree_value_type *vt = &info->value_type;
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BUG_ON(new_nr > le32_to_cpu(ab->max_entries));
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BUG_ON(new_nr > le32_to_cpu(ab->nr_entries));
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nr_entries = le32_to_cpu(ab->nr_entries);
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for (i = nr_entries; i > new_nr; i--)
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if (vt->dec)
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vt->dec(vt->context, element_at(info, ab, i - 1));
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ab->nr_entries = cpu_to_le32(new_nr);
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}
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/*
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* Read locks a block, and coerces it to an array block. The caller must
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* unlock 'block' when finished.
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*/
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static int get_ablock(struct dm_array_info *info, dm_block_t b,
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struct dm_block **block, struct array_block **ab)
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{
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int r;
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r = dm_tm_read_lock(info->btree_info.tm, b, &array_validator, block);
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if (r)
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return r;
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*ab = dm_block_data(*block);
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return 0;
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}
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/*
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* Unlocks an array block.
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*/
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static int unlock_ablock(struct dm_array_info *info, struct dm_block *block)
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{
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return dm_tm_unlock(info->btree_info.tm, block);
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}
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/*----------------------------------------------------------------*/
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/*
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* Btree manipulation.
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*/
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/*
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* Looks up an array block in the btree, and then read locks it.
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*
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* index is the index of the index of the array_block, (ie. the array index
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* / max_entries).
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*/
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static int lookup_ablock(struct dm_array_info *info, dm_block_t root,
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unsigned index, struct dm_block **block,
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struct array_block **ab)
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{
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int r;
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uint64_t key = index;
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__le64 block_le;
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r = dm_btree_lookup(&info->btree_info, root, &key, &block_le);
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if (r)
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return r;
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return get_ablock(info, le64_to_cpu(block_le), block, ab);
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}
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/*
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* Insert an array block into the btree. The block is _not_ unlocked.
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*/
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static int insert_ablock(struct dm_array_info *info, uint64_t index,
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struct dm_block *block, dm_block_t *root)
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{
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__le64 block_le = cpu_to_le64(dm_block_location(block));
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__dm_bless_for_disk(block_le);
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return dm_btree_insert(&info->btree_info, *root, &index, &block_le, root);
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}
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/*
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* Looks up an array block in the btree. Then shadows it, and updates the
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* btree to point to this new shadow. 'root' is an input/output parameter
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* for both the current root block, and the new one.
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*/
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static int shadow_ablock(struct dm_array_info *info, dm_block_t *root,
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unsigned index, struct dm_block **block,
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struct array_block **ab)
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{
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int r, inc;
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uint64_t key = index;
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dm_block_t b;
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__le64 block_le;
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/*
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* lookup
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*/
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r = dm_btree_lookup(&info->btree_info, *root, &key, &block_le);
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if (r)
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return r;
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b = le64_to_cpu(block_le);
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/*
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* shadow
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*/
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r = dm_tm_shadow_block(info->btree_info.tm, b,
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&array_validator, block, &inc);
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if (r)
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return r;
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*ab = dm_block_data(*block);
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if (inc)
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inc_ablock_entries(info, *ab);
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/*
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* Reinsert.
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*
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* The shadow op will often be a noop. Only insert if it really
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* copied data.
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*/
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if (dm_block_location(*block) != b) {
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/*
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* dm_tm_shadow_block will have already decremented the old
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* block, but it is still referenced by the btree. We
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* increment to stop the insert decrementing it below zero
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* when overwriting the old value.
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*/
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dm_tm_inc(info->btree_info.tm, b);
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r = insert_ablock(info, index, *block, root);
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}
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return r;
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}
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/*
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* Allocate an new array block, and fill it with some values.
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*/
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static int insert_new_ablock(struct dm_array_info *info, size_t size_of_block,
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uint32_t max_entries,
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unsigned block_index, uint32_t nr,
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const void *value, dm_block_t *root)
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{
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int r;
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struct dm_block *block;
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struct array_block *ab;
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r = alloc_ablock(info, size_of_block, max_entries, &block, &ab);
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if (r)
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return r;
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fill_ablock(info, ab, value, nr);
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r = insert_ablock(info, block_index, block, root);
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unlock_ablock(info, block);
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return r;
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}
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static int insert_full_ablocks(struct dm_array_info *info, size_t size_of_block,
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unsigned begin_block, unsigned end_block,
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unsigned max_entries, const void *value,
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dm_block_t *root)
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{
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int r = 0;
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for (; !r && begin_block != end_block; begin_block++)
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r = insert_new_ablock(info, size_of_block, max_entries, begin_block, max_entries, value, root);
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return r;
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}
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/*
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* There are a bunch of functions involved with resizing an array. This
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* structure holds information that commonly needed by them. Purely here
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* to reduce parameter count.
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*/
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struct resize {
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/*
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* Describes the array.
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*/
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struct dm_array_info *info;
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/*
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* The current root of the array. This gets updated.
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*/
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dm_block_t root;
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/*
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* Metadata block size. Used to calculate the nr entries in an
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* array block.
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*/
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size_t size_of_block;
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/*
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* Maximum nr entries in an array block.
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*/
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unsigned max_entries;
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/*
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* nr of completely full blocks in the array.
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*
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* 'old' refers to before the resize, 'new' after.
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*/
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unsigned old_nr_full_blocks, new_nr_full_blocks;
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/*
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* Number of entries in the final block. 0 iff only full blocks in
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* the array.
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*/
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unsigned old_nr_entries_in_last_block, new_nr_entries_in_last_block;
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/*
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* The default value used when growing the array.
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*/
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const void *value;
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};
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/*
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* Removes a consecutive set of array blocks from the btree. The values
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* in block are decremented as a side effect of the btree remove.
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*
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* begin_index - the index of the first array block to remove.
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* end_index - the one-past-the-end value. ie. this block is not removed.
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*/
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static int drop_blocks(struct resize *resize, unsigned begin_index,
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unsigned end_index)
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{
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int r;
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while (begin_index != end_index) {
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uint64_t key = begin_index++;
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r = dm_btree_remove(&resize->info->btree_info, resize->root,
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&key, &resize->root);
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if (r)
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return r;
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}
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return 0;
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}
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/*
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* Calculates how many blocks are needed for the array.
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*/
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static unsigned total_nr_blocks_needed(unsigned nr_full_blocks,
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unsigned nr_entries_in_last_block)
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{
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return nr_full_blocks + (nr_entries_in_last_block ? 1 : 0);
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}
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|
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/*
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* Shrink an array.
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*/
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static int shrink(struct resize *resize)
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{
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int r;
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unsigned begin, end;
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struct dm_block *block;
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struct array_block *ab;
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|
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/*
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* Lose some blocks from the back?
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*/
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if (resize->new_nr_full_blocks < resize->old_nr_full_blocks) {
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begin = total_nr_blocks_needed(resize->new_nr_full_blocks,
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resize->new_nr_entries_in_last_block);
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end = total_nr_blocks_needed(resize->old_nr_full_blocks,
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resize->old_nr_entries_in_last_block);
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r = drop_blocks(resize, begin, end);
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if (r)
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return r;
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}
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|
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/*
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* Trim the new tail block
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*/
|
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if (resize->new_nr_entries_in_last_block) {
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r = shadow_ablock(resize->info, &resize->root,
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resize->new_nr_full_blocks, &block, &ab);
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if (r)
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return r;
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|
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trim_ablock(resize->info, ab, resize->new_nr_entries_in_last_block);
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unlock_ablock(resize->info, block);
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}
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return 0;
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}
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|
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/*
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* Grow an array.
|
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*/
|
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static int grow_extend_tail_block(struct resize *resize, uint32_t new_nr_entries)
|
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{
|
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int r;
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struct dm_block *block;
|
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struct array_block *ab;
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r = shadow_ablock(resize->info, &resize->root,
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resize->old_nr_full_blocks, &block, &ab);
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if (r)
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return r;
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fill_ablock(resize->info, ab, resize->value, new_nr_entries);
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unlock_ablock(resize->info, block);
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return r;
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}
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|
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static int grow_add_tail_block(struct resize *resize)
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{
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return insert_new_ablock(resize->info, resize->size_of_block,
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resize->max_entries,
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resize->new_nr_full_blocks,
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resize->new_nr_entries_in_last_block,
|
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resize->value, &resize->root);
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}
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|
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static int grow_needs_more_blocks(struct resize *resize)
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{
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int r;
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unsigned old_nr_blocks = resize->old_nr_full_blocks;
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|
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if (resize->old_nr_entries_in_last_block > 0) {
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old_nr_blocks++;
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|
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r = grow_extend_tail_block(resize, resize->max_entries);
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if (r)
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return r;
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}
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|
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r = insert_full_ablocks(resize->info, resize->size_of_block,
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old_nr_blocks,
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resize->new_nr_full_blocks,
|
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resize->max_entries, resize->value,
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&resize->root);
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if (r)
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return r;
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|
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if (resize->new_nr_entries_in_last_block)
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r = grow_add_tail_block(resize);
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return r;
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}
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|
|
|
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)
|
|
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);
|
|
|
|
/*----------------------------------------------------------------*/
|
|
|