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