+++ /dev/null
-/*
- * Copyright (C) 2013 Andrea Mazzoleni
- *
- * This program is free software: you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation, either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- */
-
-#ifndef __RAID_H
-#define __RAID_H
-
-/**
- * RAID mode supporting up to 6 parities.
- *
- * It requires SSSE3 to get good performance with triple or more parities.
- *
- * This is the default mode set after calling raid_init().
- */
-#define RAID_MODE_CAUCHY 0
-
-/**
- * RAID mode supporting up to 3 parities,
- *
- * It has a fast triple parity implementation without SSSE3, but it cannot
- * go beyond triple parity.
- *
- * This is mostly intended for low end CPUs like ARM and AMD Athlon.
- */
-#define RAID_MODE_VANDERMONDE 1
-
-/**
- * Maximum number of parity disks supported.
- */
-#define RAID_PARITY_MAX 6
-
-/**
- * Maximum number of data disks supported.
- */
-#define RAID_DATA_MAX 251
-
-/**
- * Initializes the RAID system.
- *
- * You must call this function before any other.
- *
- * The RAID system is initialized in the RAID_MODE_CAUCHY mode.
- */
-void raid_init(void);
-
-/**
- * Runs a basic functionality self test.
- *
- * The test is immediate, and it's intended to be run at application
- * startup to check the integrity of the RAID system.
- *
- * It returns 0 on success.
- */
-int raid_selftest(void);
-
-/**
- * Sets the mode to use. One of RAID_MODE_*.
- *
- * You can change mode at any time, and it will affect next calls to raid_gen(),
- * raid_rec() and raid_data().
- *
- * The two modes are compatible for the first two levels of parity.
- * The third one is different.
- */
-void raid_mode(int mode);
-
-/**
- * Sets the zero buffer to use in recovering.
- *
- * Before calling raid_rec() and raid_data() you must provide a memory
- * buffer filled with zero with the same size of the blocks to recover.
- *
- * This buffer is only read and never written.
- */
-void raid_zero(void *zero);
-
-/**
- * Computes parity blocks.
- *
- * This function computes the specified number of parity blocks of the
- * provided set of data blocks.
- *
- * Each parity block allows to recover one data block.
- *
- * @nd Number of data blocks.
- * @np Number of parities blocks to compute.
- * @size Size of the blocks pointed by @v. It must be a multiplier of 64.
- * @v Vector of pointers to the blocks of data and parity.
- * It has (@nd + @np) elements. The starting elements are the blocks for
- * data, following with the parity blocks.
- * Data blocks are only read and not modified. Parity blocks are written.
- * Each block has @size bytes.
- */
-void raid_gen(int nd, int np, size_t size, void **v);
-
-/**
- * Recovers failures in data and parity blocks.
- *
- * This function recovers all the data and parity blocks marked as bad
- * in the @ir vector.
- *
- * Ensure to have @nr <= @np, otherwise recovering is not possible.
- *
- * The parities blocks used for recovering are automatically selected from
- * the ones NOT present in the @ir vector.
- *
- * In case there are more parity blocks than needed, the parities at lower
- * indexes are used in the recovering, and the others are ignored.
- *
- * Note that no internal integrity check is done when recovering. If the
- * provided parities are correct, the resulting data will be correct.
- * If parities are wrong, the resulting recovered data will be wrong.
- * This happens even in the case you have more parities blocks than needed,
- * and some form of integrity verification would be possible.
- *
- * @nr Number of failed data and parity blocks to recover.
- * @ir[] Vector of @nr indexes of the failed data and parity blocks.
- * The indexes start from 0. They must be in order.
- * The first parity is represented with value @nd, the second with value
- * @nd + 1, just like positions in the @v vector.
- * @nd Number of data blocks.
- * @np Number of parity blocks.
- * @size Size of the blocks pointed by @v. It must be a multiplier of 64.
- * @v Vector of pointers to the blocks of data and parity.
- * It has (@nd + @np) elements. The starting elements are the blocks
- * for data, following with the parity blocks.
- * Each block has @size bytes.
- */
-void raid_rec(int nr, int *ir, int nd, int np, size_t size, void **v);
-
-/**
- * Recovers failures in data blocks only.
- *
- * This function recovers all the data blocks marked as bad in the @id vector.
- * The parity blocks are not modified.
- *
- * @nr Number of failed data blocks to recover.
- * @id[] Vector of @nr indexes of the data blocks to recover.
- * The indexes start from 0. They must be in order.
- * @ip[] Vector of @nr indexes of the parity blocks to use for recovering.
- * The indexes start from 0. They must be in order.
- * @nd Number of data blocks.
- * @size Size of the blocks pointed by @v. It must be a multiplier of 64.
- * @v Vector of pointers to the blocks of data and parity.
- * It has (@nd + @ip[@nr - 1] + 1) elements. The starting elements are the
- * blocks for data, following with the parity blocks.
- * Each blocks has @size bytes.
- */
-void raid_data(int nr, int *id, int *ip, int nd, size_t size, void **v);
-
-/**
- * Check the provided failed blocks combination.
- *
- * This function checks if the specified failed blocks combination satisfies
- * the redundancy information. A combination is assumed matching, if the
- * remaining valid parity is matching the expected value after recovering.
- *
- * The number of failed blocks @nr must be strictly less than the number of
- * parities @np, because you need one more parity to validate the recovering.
- *
- * No data or parity blocks are modified.
- *
- * @nr Number of failed data and parity blocks.
- * @ir[] Vector of @nr indexes of the failed data and parity blocks.
- * The indexes start from 0. They must be in order.
- * The first parity is represented with value @nd, the second with value
- * @nd + 1, just like positions in the @v vector.
- * @nd Number of data blocks.
- * @np Number of parity blocks.
- * @size Size of the blocks pointed by @v. It must be a multiplier of 64.
- * @v Vector of pointers to the blocks of data and parity.
- * It has (@nd + @np) elements. The starting elements are the blocks
- * for data, following with the parity blocks.
- * Each block has @size bytes.
- * @return 0 if the check is satisfied. -1 otherwise.
- */
-int raid_check(int nr, int *ir, int nd, int np, size_t size, void **v);
-
-/**
- * Scan for failed blocks.
- *
- * This function identifies the failed data and parity blocks using the
- * available redundancy.
- *
- * It uses a brute force method, and then the call can be expansive.
- * The expected execution time is proportional at the binomial coefficient
- * @np + @nd choose @np - 1, usually written as:
- *
- * ( @np + @nd )
- * ( )
- * ( @np - 1 )
- *
- * No data or parity blocks are modified.
- *
- * The failed block indexes are returned in the @ir vector.
- * It must have space for at least @np - 1 values.
- *
- * The returned @ir vector can then be used in a raid_rec() call to recover
- * the failed data and parity blocks.
- *
- * @ir[] Vector filled with the indexes of the failed data and parity blocks.
- * The indexes start from 0 and they are in order.
- * The first parity is represented with value @nd, the second with value
- * @nd + 1, just like positions in the @v vector.
- * @nd Number of data blocks.
- * @np Number of parity blocks.
- * @size Size of the blocks pointed by @v. It must be a multiplier of 64.
- * @v Vector of pointers to the blocks of data and parity.
- * It has (@nd + @np) elements. The starting elements are the blocks
- * for data, following with the parity blocks.
- * Each block has @size bytes.
- * @return Number of block indexes returned in the @ir vector.
- * 0 if no error is detected.
- * -1 if it's not possible to identify the failed disks.
- */
-int raid_scan(int *ir, int nd, int np, size_t size, void **v);
-
-#endif
-
projects / bcachefs-tools-debian / blobdiff