snapraid/cmdline/parity.c

/*
 * 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/>.
 */

#include "portable.h"

#include "support.h"
#include "elem.h"
#include "state.h"
#include "parity.h"
#include "handle.h"

/****************************************************************************/
/* parity */

block_off_t parity_allocated_size(struct snapraid_state* state)
{
	block_off_t parity_block;
	tommy_node* i;

	/* compute the size of the parity file */
	parity_block = 0;
	for (i = state->disklist; i != 0; i = i->next) {
		struct snapraid_disk* disk = i->data;

		/* start from the declared size */
		block_off_t block = fs_size(disk);

		/* decrease the block until an allocated one, but part of a file */
		/* we don't stop at deleted blocks, because we want to have them cleared */
		/* if they are at the end of the parity */
		while (block > parity_block && !block_has_file(fs_par2block_find(disk, block - 1)))
			--block;

		/* get the highest value */
		if (block > parity_block)
			parity_block = block;
	}

	return parity_block;
}

block_off_t parity_used_size(struct snapraid_state* state)
{
	block_off_t parity_block;
	tommy_node* i;

	/* compute the size of the parity file */
	parity_block = 0;
	for (i = state->disklist; i != 0; i = i->next) {
		struct snapraid_disk* disk = i->data;

		/* start from the declared size */
		block_off_t block = fs_size(disk);

		/* decrease the block until an used one */
		while (block > parity_block && !block_has_file_and_valid_parity(fs_par2block_find(disk, block - 1)))
			--block;

		/* get the highest value */
		if (block > parity_block)
			parity_block = block;
	}

	return parity_block;
}

int parity_is_invalid(struct snapraid_state* state)
{
	block_off_t blockmax;
	block_off_t i;

	blockmax = parity_allocated_size(state);

	for (i = 0; i < blockmax; ++i) {
		tommy_node* node_disk;
		int one_invalid;
		int one_valid;

		/* for each disk */
		one_invalid = 0;
		one_valid = 0;
		for (node_disk = state->disklist; node_disk != 0; node_disk = node_disk->next) {
			struct snapraid_disk* disk = node_disk->data;
			struct snapraid_block* block = fs_par2block_find(disk, i);

			if (block_has_file(block))
				one_valid = 1;
			if (block_has_invalid_parity(block))
				one_invalid = 1;
		}

		/* if both valid and invalid, we need to update */
		if (one_invalid && one_valid)
			return 1;
	}

	return 0;
}

void parity_overflow(struct snapraid_state* state, data_off_t size)
{
	tommy_node* i;
	block_off_t blockalloc;
	int first = 1;
	char esc_buffer[ESC_MAX];

	/* don't report if everything is outside or if the file is not accessible */
	if (size == 0) {
		return;
	}

	blockalloc = size / state->block_size;

	/* for all disks */
	for (i = state->disklist; i != 0; i = i->next) {
		struct snapraid_disk* disk = i->data;
		tommy_node* j;

		/* for all files */
		for (j = disk->filelist; j != 0; j = j->next) {
			struct snapraid_file* file = j->data;

			if (file->blockmax > 0) {
				block_off_t parity_pos = fs_file2par_get(disk, file, file->blockmax - 1);
				if (parity_pos >= blockalloc) {
					log_tag("outofparity:%s:%s\n", disk->name, esc(file->sub, esc_buffer));
					if (first) {
						first = 0;
						log_fatal("\nYour data requires more parity than the available space.\n");
						log_fatal("Please move the files 'outofparity' to another data disk:\n");
					}
					log_fatal("outofparity %s%s\n", disk->dir, file->sub);
				}
			}
		}
	}
}

void parity_size(struct snapraid_parity_handle* handle, data_off_t* out_size)
{
	unsigned s;
	data_off_t size;

	/* now compute the size */
	size = 0;
	for (s = 0;s < handle->split_mac;++s) {
		struct snapraid_split_handle* split = &handle->split_map[s];

		/* check for validity */
		if (split->st.st_size < 0)
			break;

		if ((uint64_t)split->st.st_size < split->size) {
			/* this is a size error, so report only up to this size */
			/* but don't fail the function */
			size += split->st.st_size;
			break;
		}

		/* ignore instead size bigger than expected */
		size += split->size;
	}

	*out_size = size;
}

int parity_create(struct snapraid_parity_handle* handle, const struct snapraid_parity* parity, unsigned level, int mode)
{
	unsigned s;

	handle->level = level;
	handle->split_mac = 0;

	for (s = 0;s < parity->split_mac;++s) {
		struct snapraid_split_handle* split = &handle->split_map[s];
		int ret;
		int flags;

		/* mark it as initialized */
		pathcpy(split->path, sizeof(split->path), parity->split_map[s].path);
		split->f = -1;
		split->size = parity->split_map[s].size;
		++handle->split_mac;

		/* opening in sequential mode in Windows */
		/* O_SEQUENTIAL: opening in sequential mode in Windows */
		flags = O_RDWR | O_CREAT | O_BINARY;
		if ((mode & MODE_SEQUENTIAL) != 0)
			flags |= O_SEQUENTIAL;
		split->f = open(split->path, flags, 0600);
		if (split->f == -1) {
			/* LCOV_EXCL_START */
			log_fatal("Error opening parity file '%s'. %s.\n", split->path, strerror(errno));
			goto bail;
			/* LCOV_EXCL_STOP */
		}

		/* get the stat info */
		ret = fstat(split->f, &split->st);
		if (ret != 0) {
			/* LCOV_EXCL_START */
			log_fatal("Error accessing parity file '%s'. %s.\n", split->path, strerror(errno));
			goto bail;
			/* LCOV_EXCL_STOP */
		}

		/**
		 * If the parity size is not yet set, set it now.
		 * This happens when expanding the number of parities.
		 */
		if (split->size == PARITY_SIZE_INVALID)
			split->size = split->st.st_size;

#if HAVE_POSIX_FADVISE
		if ((mode & MODE_SEQUENTIAL) != 0) {
			/* advise sequential access */
			ret = posix_fadvise(split->f, 0, 0, POSIX_FADV_SEQUENTIAL);
			if (ret != 0) {
				/* LCOV_EXCL_START */
				log_fatal("Error advising parity file '%s'. %s.\n", split->path, strerror(ret));
				goto bail;
				/* LCOV_EXCL_STOP */
			}
		}
#endif
	}

	return 0;

bail:
	/* LCOV_EXCL_START */
	for (s = 0;s < handle->split_mac;++s) {
		struct snapraid_split_handle* split = &handle->split_map[s];
		close(split->f);
		split->f = -1;
	}
	return -1;
	/* LCOV_EXCL_STOP */
}

static int parity_handle_grow(struct snapraid_split_handle* split, data_off_t size, int skip_fallocate)
{
	int ret;

#if HAVE_FALLOCATE
	if (!skip_fallocate) {
		/* allocate real space using the specific Linux fallocate() operation. */
		/* If the underline file-system doesn't support it, this operation fails, */
		/* instead posix_fallocate() fallbacks to write the whole file. */
		ret = fallocate(split->f, 0, 0, size);

		/* fallocate() returns the error number as positive integer, */
		/* and in this case it doesn't set errno, just like posix_fallocate() */
		/* Checking the glibc code (2.11.1 and 2.14.1) it seems that ENOSYS */
		/* may be returned in errno, so we support both the return way */
		if (ret > 0) { /* if a positive error is returned, convert it to errno */
			/* LCOV_EXCL_START */
			errno = ret;
			ret = -1;
			/* LCOV_EXCL_STOP */
		}
	} else {
		errno = EOPNOTSUPP;
		ret = -1;
	}

	/* we get EOPNOTSUPP if the operation is not supported, like in ext3/ext2 */
	/* or ENOSYS with kernel before 2.6.23 */
	if (errno == EOPNOTSUPP || errno == ENOSYS) {
		/* fallback using ftruncate() */
		ret = ftruncate(split->f, size);
	}
#else
	(void)skip_fallocate; /* avoid the warning */

	/* allocate using a sparse file */
	ret = ftruncate(split->f, size);
#endif

	return ret;
}

/**
 * Get the highest bit set.
 */
uint64_t hbit_u64(uint64_t v)
{
	unsigned ilog;

	ilog = 0;
	while ((v /= 2) != 0)
		++ilog;

	return 1ULL << ilog;
}

static int parity_handle_fill(struct snapraid_split_handle* split, data_off_t size, uint32_t block_size, int skip_fallocate)
{
	data_off_t base;
	data_off_t delta;
	data_off_t block_mask;

	/* mask of bits used by the block size */
	block_mask = ((data_off_t)block_size) - 1;

	/* present size */
	base = split->st.st_size;

	/* truncate it to block size multiplier */
	/* in case of damage the size may get wrong */
	base &= ~block_mask;

	/* size we have to increase */
	delta = size - base;

	/* grow the size one bit at time, like a kind of binary search */
	while (delta != 0) {
		int ret;
		data_off_t run = hbit_u64(delta);

		ret = parity_handle_grow(split, base + run, skip_fallocate);

		if (ret != 0) {
			/* we cannot grow, fallback to the smaller bits */
			delta = run - 1;

			/* mask out the block size */
			delta &= ~block_mask;
		} else {
			/* mask out this bit */
			delta &= ~run;
			base += run;
		}
	}

	/* reallocate the expected size */
	/* if this fail, is there a problem */
	return parity_handle_grow(split, base, skip_fallocate);
}

static int parity_handle_shrink(struct snapraid_split_handle* split, data_off_t size)
{
	return ftruncate(split->f, size);
}

static int parity_handle_chsize(struct snapraid_split_handle* split, data_off_t size, uint32_t block_size, int skip_fallocate)
{
	int ret;
	int f_ret;
	int f_errno;
	int f_dir;

	if (split->st.st_size < size) {
		f_ret = parity_handle_fill(split, size, block_size, skip_fallocate);
		f_errno = errno;
		f_dir = 1;
	} else if (split->st.st_size > size) {
		f_ret = parity_handle_shrink(split, size);
		f_errno = errno;
		f_dir = -1;
	} else {
		f_ret = 0;
		f_errno = 0;
		f_dir = 0;
	}

	/* get the stat info */
	ret = fstat(split->f, &split->st);
	if (ret != 0) {
		/* LCOV_EXCL_START */
		log_fatal("Error accessing parity file '%s'. %s.\n", split->path, strerror(errno));
		return -1;
		/* LCOV_EXCL_STOP */
	}

	/* now check the error */
	if (f_ret != 0) {
		/* LCOV_EXCL_START */
		if (f_dir > 0) {
			if (f_errno == ENOSPC) {
				log_fatal("Failed to grow parity file '%s' to size %" PRIu64 " due lack of space.\n", split->path, size);
			} else {
				log_fatal("Error growing parity file '%s' to size %" PRIu64 ". Do you have enough space? %s.\n", split->path, size, strerror(f_errno));
			}
		} else {
			log_fatal("Error truncating parity file '%s' to size %" PRIu64 ". %s.\n", split->path, size, strerror(f_errno));
		}
		return -1;
		/* LCOV_EXCL_STOP */
	}

	return 0;
}

static int parity_split_is_fixed(struct snapraid_parity_handle* handle, unsigned s)
{
	/* next one */
	++s;

	/* the latest one is always growing */
	if (s >= handle->split_mac)
		return 0;

	/* if the next it's 0, this one is growing */
	if (handle->split_map[s].size == 0)
		return 0;

	return 1;
}

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 ret;
	unsigned s;

	if (size < 0)
		return -1;

	for (s = 0;s < handle->split_mac;++s) {
		struct snapraid_split_handle* split = &handle->split_map[s];
		int is_fixed = parity_split_is_fixed(handle, s);
		data_off_t run;

		if (is_fixed) {
			if ((uint64_t)size <= split->size) {
				is_fixed = 0; /* not fixed anymore */
				run = size;
			} else {
				run = split->size;
			}
		} else {
			run = size;
		}
		
		ret = parity_handle_chsize(split, run, block_size, skip_fallocate);
		if (ret != 0)
			return -1;

		if (split->st.st_size > run) {
			/* LCOV_EXCL_START */
			log_fatal("Unexpected over resizing parity file '%s' to size %" PRIu64 " resulting in size %" PRIu64 ".\n", split->path, run, split->st.st_size);
			return -1;
			/* LCOV_EXCL_STOP */
		} else if (is_fixed && split->st.st_size < run) {
			/* LCOV_EXCL_START */
			log_fatal("Failed restoring parity file '%s' to size %" PRIu64 " resulting in size %" PRIu64 ".\n", split->path, run, split->st.st_size);
			return -1;
			/* LCOV_EXCL_STOP */
		} else {
			size -= split->st.st_size;
			split->size = split->st.st_size;
		}
	}

	/* now copy the new size in the parity data */
	if (is_modified)
		*is_modified = 0;

	for (s = 0;s < handle->split_mac;++s) {
		struct snapraid_split_handle* split = &handle->split_map[s];

		if (parity->split_map[s].size != split->size) {
			parity->split_map[s].size = split->size;
			if (is_modified)
				*is_modified = 1;
		}
	}

	return 0;
}

int parity_open(struct snapraid_parity_handle* handle, const struct snapraid_parity* parity, unsigned level, int mode)
{
	unsigned s;

	handle->level = level;
	handle->split_mac = 0;

	for (s = 0;s < parity->split_mac;++s) {
		struct snapraid_split_handle* split = &handle->split_map[s];
		int ret;
		int flags;

		/* mark it as initialized */
		pathcpy(split->path, sizeof(split->path), parity->split_map[s].path);
		split->f = -1;
		split->size = parity->split_map[s].size;
		++handle->split_mac;

		/* open for read */
		/* O_SEQUENTIAL: opening in sequential mode in Windows */
		/* O_NOATIME: do not change access time */
		flags = O_RDONLY | O_BINARY;
		if ((mode & MODE_SEQUENTIAL) != 0)
			flags |= O_SEQUENTIAL;
		split->f = open_noatime(split->path, flags);
		if (split->f == -1) {
			log_fatal("Error opening parity file '%s'. %s.\n", split->path, strerror(errno));
			goto bail;
		}

		/* get the stat info */
		ret = fstat(split->f, &split->st);
		if (ret != 0) {
			/* LCOV_EXCL_START */
			log_fatal("Error accessing parity file '%s'. %s.\n", split->path, strerror(errno));
			goto bail;
			/* LCOV_EXCL_STOP */
		}

		/**
		 * If the parity size is not yet set, set it now.
		 * This happens when expanding the number of parities.
		 */
		if (split->size == PARITY_SIZE_INVALID)
			split->size = split->st.st_size;

#if HAVE_POSIX_FADVISE
		if ((mode & MODE_SEQUENTIAL) != 0) {
			/* advise sequential access */
			ret = posix_fadvise(split->f, 0, 0, POSIX_FADV_SEQUENTIAL);
			if (ret != 0) {
				/* LCOV_EXCL_START */
				log_fatal("Error advising parity file '%s'. %s.\n", split->path, strerror(ret));
				goto bail;
				/* LCOV_EXCL_STOP */
			}
		}
#endif
	}

	return 0;

bail:
	/* LCOV_EXCL_START */
	for (s = 0;s < handle->split_mac;++s) {
		struct snapraid_split_handle* split = &handle->split_map[s];
		close(split->f);
		split->f = -1;
	}
	return -1;
	/* LCOV_EXCL_STOP */
}

int parity_sync(struct snapraid_parity_handle* handle)
{
#if HAVE_FSYNC
	unsigned s;

	for (s = 0;s < handle->split_mac;++s) {
		struct snapraid_split_handle* split = &handle->split_map[s];
		int ret;

		/* Ensure that data changes are written to disk. */
		/* This is required to ensure that parity is more updated than content */
		/* in case of a system crash. */
		ret = fsync(split->f);
		if (ret != 0) {
			/* LCOV_EXCL_START */
			log_fatal("Error synching parity file '%s'. %s.\n", split->path, strerror(errno));
			return -1;
			/* LCOV_EXCL_STOP */
		}
	}
#endif

	return 0;
}

int parity_close(struct snapraid_parity_handle* handle)
{
	unsigned s;
	int f_ret = 0;

	for (s = 0;s < handle->split_mac;++s) {
		struct snapraid_split_handle* split = &handle->split_map[s];
		int ret;

		ret = close(split->f);
		if (ret != 0) {
			/* LCOV_EXCL_START */
			/* This is a serious error, as it may be the result of a failed write */
			/* identified at later time. */
			/* In a normal file-system (not NFS) it should never happen */
			log_fatal("Error closing parity file '%s'. %s.\n", split->path, strerror(errno));
			f_ret = -1;
			/* LCOV_EXCL_STOP */

			/* continue to close the others */
		}

		/* reset the descriptor */
		split->f = -1;
	}

	return f_ret;
}

struct snapraid_split_handle* parity_split_find(struct snapraid_parity_handle* handle, data_off_t* offset)
{
	unsigned s;

	if (*offset < 0)
		return 0;

	for (s = 0;s < handle->split_mac;++s) {
		struct snapraid_split_handle* split = &handle->split_map[s];

		if ((uint64_t)*offset < split->size)
			return split;

		*offset -= split->size;
	}

	return 0;
}

int parity_write(struct snapraid_parity_handle* handle, block_off_t pos, unsigned char* block_buffer, unsigned block_size)
{
	ssize_t write_ret;
	data_off_t offset;
	struct snapraid_split_handle* split;

	offset = pos * (data_off_t)block_size;

	split = parity_split_find(handle, &offset);
	if (!split) {
		/* LCOV_EXCL_START */
		log_fatal("Writing parity data outside range at extra offset %" PRIu64 ".\n", offset);
		return -1;
		/* LCOV_EXCL_STOP */
	}

	write_ret = pwrite(split->f, block_buffer, block_size, offset);
	if (write_ret != (ssize_t)block_size) { /* conversion is safe because block_size is always small */
		/* LCOV_EXCL_START */
		if (errno == ENOSPC) {
			log_fatal("Failed to grow parity file '%s' using write due lack of space.\n", split->path);
		} else {
			log_fatal("Error writing file '%s'. %s.\n", split->path, strerror(errno));
		}
		return -1;
		/* LCOV_EXCL_STOP */
	}

	/* Here doesn't make sense to call posix_fadvise(..., POSIX_FADV_DONTNEED) because */
	/* at this time the data is still in not yet written and it cannot be discharged. */

	return 0;
}

int parity_read(struct snapraid_parity_handle* handle, block_off_t pos, unsigned char* block_buffer, unsigned block_size, fptr* out)
{
	ssize_t read_ret;
	data_off_t offset;
	unsigned count;
	struct snapraid_split_handle* split;

	offset = pos * (data_off_t)block_size;

	split = parity_split_find(handle, &offset);
	if (!split) {
		/* LCOV_EXCL_START */
		out("Reading parity data outside range at extra offset %" PRIu64 ".\n", offset);
		return -1;
		/* LCOV_EXCL_STOP */
	}

	count = 0;
	do {
		read_ret = pread(split->f, block_buffer + count, block_size - count, offset + count);
		if (read_ret < 0) {
			/* LCOV_EXCL_START */
			out("Error reading file '%s' at offset %" PRIu64 " for size %u. %s.\n", split->path, offset + count, block_size - count, strerror(errno));
			return -1;
			/* LCOV_EXCL_STOP */
		}
		if (read_ret == 0) {
			/* LCOV_EXCL_START */
			out("Unexpected end of file '%s' at offset %" PRIu64 ". %s.\n", split->path, offset, strerror(errno));
			return -1;
			/* LCOV_EXCL_STOP */
		}

		count += read_ret;
	} while (count < block_size);

	/* Here isn't needed to call posix_fadvise(..., POSIX_FADV_DONTNEED) */
	/* because we already advised sequential access with POSIX_FADV_SEQUENTIAL. */
	/* In Linux 2.6.33 it's enough to ensure that data is not kept in the cache. */
	/* Better to do nothing and save a syscall for each block. */

	return block_size;
}