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/*
* Copyright (C) 2011 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 3 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.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#ifndef __PARITY_H
#define __PARITY_H
#include "support.h"
/****************************************************************************/
/* parity */
struct snapraid_split_handle {
char path[PATH_MAX]; /**< Path of the file. */
int f; /**< Handle of the files. */
struct stat st; /**< Stat info of the opened file. */
struct advise_struct advise; /**< Advise information. */
/**
* Size of the parity split.
* Only the latest not zero size is allowed to grow.
* Note that this value CANNOT be PARITY_SIZE_INVALID.
*/
data_off_t size;
/**
* Valid size of the parity split.
* This is the size effectively written, and not the result of a chsize operation.
* It's used to make read operations failing if read over that size.
*
* Parity is also truncated to that size when fixing it, in case of a Break (Ctrl+C)
* of the program.
*/
data_off_t valid_size;
/**
* Artificial size limit for testing.
* 0 means unlimited.
*/
data_off_t limit_size;
};
struct snapraid_parity_handle {
struct snapraid_split_handle split_map[SPLIT_MAX];
unsigned split_mac; /**< Number of parity splits. */
unsigned level; /**< Level of the parity. */
};
/**
* Compute the size of the allocated parity data in number of blocks.
*
* This includes parity blocks not yet written and still invalid.
*/
block_off_t parity_allocated_size(struct snapraid_state* state);
/**
* Compute the size of the used parity data in number of blocks.
*
* This includes only parity blocks used for files, not counting
* potential invalid parity at the end.
*
* If the array is fully synced there is no difference between
* parity_allocate_size() and parity_used_size().
* But if the sync is interrupted, the parity_used_size() returns
* the position of the latest BLK block, ignoring CHG, REL and DELETED ones,
* because their parity may be still not even written in the parity file.
*/
block_off_t parity_used_size(struct snapraid_state* state);
/**
* Check if the parity needs to be updated with a "sync".
*
* This is the same logic used in "status" to detect an incomplete "sync",
* that ignores invalid block, if they are not used by a file in any disk.
* This means that DELETED blocks won't necessarily imply an invalid parity.
*/
int parity_is_invalid(struct snapraid_state* state);
/**
* Report all the files outside the specified parity size.
*/
void parity_overflow(struct snapraid_state* state, data_off_t size);
/**
* Create the parity file.
* \param out_size Return the size of the parity file.
*/
int parity_create(struct snapraid_parity_handle* handle, const struct snapraid_parity* parity, unsigned level, int mode, uint32_t block_size, data_off_t limit_size);
/**
* Change the parity size.
* \param out_size Return the size of the parity file. The out_size is set also on error to reflect a partial resize.
*/
int parity_chsize(struct snapraid_parity_handle* handle, struct snapraid_parity* parity, int* is_modified, data_off_t size, uint32_t block_size, int skip_fallocate, int skip_space_holder);
/**
* Get the size of the parity.
*
* This returns the cached/expected version of the split sizes, and not the real file size.
*/
void parity_size(struct snapraid_parity_handle* handle, data_off_t* out_size);
/**
* Open an already existing parity file.
*/
int parity_open(struct snapraid_parity_handle* handle, const struct snapraid_parity* parity, unsigned level, int mode, uint32_t block_size, data_off_t limit_size);
/**
* Flush the parity file in the disk.
*/
int parity_sync(struct snapraid_parity_handle* handle);
/**
* Truncate the parity file to the valid size.
*/
int parity_truncate(struct snapraid_parity_handle* handle);
/**
* Close the parity file.
*/
int parity_close(struct snapraid_parity_handle* handle);
/**
* Read a block from the parity file.
*/
int parity_read(struct snapraid_parity_handle* handle, block_off_t pos, unsigned char* block_buffer, unsigned block_size, fptr* out);
/**
* Write a block in the parity file.
*/
int parity_write(struct snapraid_parity_handle* handle, block_off_t pos, unsigned char* block_buffer, unsigned block_size);
#endif
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