/* * Copyright (c) 2008, 2009, Swedish Institute of Computer Science * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. Neither the name of the Institute nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * This file is part of the Contiki operating system. * */ /** * \file * Coffee: A file system for a variety of storage types in * memory-constrained devices. * * For further information, see "Enabling Large-Scale Storage in * Sensor Networks with the Coffee File System" in the proceedings * of ACM/IEEE IPSN 2009. * * \author * Nicolas Tsiftes */ #include #include #define DEBUG 0 #if DEBUG #include #define PRINTF(...) printf(__VA_ARGS__) #else #define PRINTF(...) #endif #include "contiki-conf.h" #include "cfs/cfs.h" #include "cfs-coffee-arch.h" #include "cfs/cfs-coffee.h" /* Micro logs enable modifications on storage types that do not support in-place updates. This applies primarily to flash memories. */ #ifndef COFFEE_MICRO_LOGS #define COFFEE_MICRO_LOGS 1 #endif /* If the files are expected to be appended to only, this parameter can be set to save some code space. */ #ifndef COFFEE_APPEND_ONLY #define COFFEE_APPEND_ONLY 0 #endif #if COFFEE_MICRO_LOGS && COFFEE_APPEND_ONLY #error "Cannot have COFFEE_APPEND_ONLY set when COFFEE_MICRO_LOGS is set." #endif /* * Prevent sectors from being erased directly after file removal. * This will level the wear across sectors better, but may lead * to longer garbage collection procedures. */ #ifndef COFFEE_EXTENDED_WEAR_LEVELLING #define COFFEE_EXTENDED_WEAR_LEVELLING 1 #endif #if COFFEE_START & (COFFEE_SECTOR_SIZE - 1) #error COFFEE_START must point to the first byte in a sector. #endif /* File descriptor flags. */ #define COFFEE_FD_FREE 0x0 #define COFFEE_FD_READ 0x1 #define COFFEE_FD_WRITE 0x2 #define COFFEE_FD_APPEND 0x4 /* File object flags. */ #define COFFEE_FILE_MODIFIED 0x1 /* Internal Coffee markers. */ #define INVALID_PAGE ((coffee_page_t)-1) #define UNKNOWN_OFFSET ((cfs_offset_t)-1) /* File removal actions. They can have the same values because they are passed as separate parameters. */ #define REMOVE_LOG 1 #define CLOSE_FDS 1 #define ALLOW_GC 1 /* "Greedy" garbage collection erases as many sectors as possible. */ #define GC_GREEDY 0 /* "Reluctant" garbage collection stops after erasing one sector. */ #define GC_RELUCTANT 1 /* File descriptor macros. */ #define FD_VALID(fd) ((fd) >= 0 && (fd) < COFFEE_FD_SET_SIZE && \ coffee_fd_set[(fd)].flags != COFFEE_FD_FREE) #define FD_READABLE(fd) (coffee_fd_set[(fd)].flags & CFS_READ) #define FD_WRITABLE(fd) (coffee_fd_set[(fd)].flags & CFS_WRITE) #define FD_APPENDABLE(fd) (coffee_fd_set[(fd)].flags & CFS_APPEND) /* File object macros. */ #define FILE_MODIFIED(file) ((file)->flags & COFFEE_FILE_MODIFIED) #define FILE_FREE(file) ((file)->max_pages == 0) #define FILE_UNREFERENCED(file) ((file)->references == 0) /* File header flags. */ #define HDR_FLAG_VALID 0x01 /* Completely written header. */ #define HDR_FLAG_ALLOCATED 0x02 /* Allocated file. */ #define HDR_FLAG_OBSOLETE 0x04 /* File marked for GC. */ #define HDR_FLAG_MODIFIED 0x08 /* Modified file, log exists. */ #define HDR_FLAG_LOG 0x10 /* Log file. */ #define HDR_FLAG_ISOLATED 0x20 /* Isolated page. */ /* File header macros. */ #define CHECK_FLAG(hdr, flag) ((hdr).flags & (flag)) #define HDR_VALID(hdr) CHECK_FLAG(hdr, HDR_FLAG_VALID) #define HDR_ALLOCATED(hdr) CHECK_FLAG(hdr, HDR_FLAG_ALLOCATED) #define HDR_FREE(hdr) !HDR_ALLOCATED(hdr) #define HDR_LOG(hdr) CHECK_FLAG(hdr, HDR_FLAG_LOG) #define HDR_MODIFIED(hdr) CHECK_FLAG(hdr, HDR_FLAG_MODIFIED) #define HDR_ISOLATED(hdr) CHECK_FLAG(hdr, HDR_FLAG_ISOLATED) #define HDR_OBSOLETE(hdr) CHECK_FLAG(hdr, HDR_FLAG_OBSOLETE) #define HDR_ACTIVE(hdr) (HDR_ALLOCATED(hdr) && \ !HDR_OBSOLETE(hdr) && \ !HDR_ISOLATED(hdr)) /* Shortcuts derived from the hardware-dependent configuration of Coffee. */ #define COFFEE_SECTOR_COUNT \ (coffee_page_t)(COFFEE_SIZE / COFFEE_SECTOR_SIZE) #define COFFEE_PAGE_COUNT \ ((coffee_page_t)(COFFEE_SIZE / COFFEE_PAGE_SIZE)) #define COFFEE_PAGES_PER_SECTOR \ ((coffee_page_t)(COFFEE_SECTOR_SIZE / COFFEE_PAGE_SIZE)) /* This structure is used for garbage collection statistics. */ struct sector_status { coffee_page_t active; coffee_page_t obsolete; coffee_page_t free; }; /* The structure of cached file objects. */ struct file { cfs_offset_t end; coffee_page_t page; coffee_page_t max_pages; int16_t record_count; uint8_t references; uint8_t flags; }; /* The file descriptor structure. */ struct file_desc { cfs_offset_t offset; struct file *file; uint8_t flags; uint8_t io_flags; }; /* The file header structure mimics the representation of file headers in the physical storage medium. */ struct file_header { coffee_page_t log_page; uint16_t log_records; uint16_t log_record_size; coffee_page_t max_pages; uint8_t deprecated_eof_hint; uint8_t flags; char name[COFFEE_NAME_LENGTH]; }; /* This is needed because of a buggy compiler. */ struct log_param { cfs_offset_t offset; char *buf; uint16_t size; }; /* * Variables that keep track of opened files and internal * optimization information for Coffee. */ static struct file coffee_files[COFFEE_MAX_OPEN_FILES]; static struct file_desc coffee_fd_set[COFFEE_FD_SET_SIZE]; static coffee_page_t next_free; static char gc_wait; /*---------------------------------------------------------------------------*/ static void write_header(struct file_header *hdr, coffee_page_t page) { hdr->flags |= HDR_FLAG_VALID; COFFEE_WRITE(hdr, sizeof(*hdr), page * COFFEE_PAGE_SIZE); } /*---------------------------------------------------------------------------*/ static void read_header(struct file_header *hdr, coffee_page_t page) { COFFEE_READ(hdr, sizeof(*hdr), page * COFFEE_PAGE_SIZE); if(DEBUG && HDR_ACTIVE(*hdr) && !HDR_VALID(*hdr)) { PRINTF("Coffee: Invalid header at page %u!\n", (unsigned)page); } } /*---------------------------------------------------------------------------*/ static cfs_offset_t absolute_offset(coffee_page_t page, cfs_offset_t offset) { return page * COFFEE_PAGE_SIZE + sizeof(struct file_header) + offset; } /*---------------------------------------------------------------------------*/ static coffee_page_t get_sector_status(coffee_page_t sector, struct sector_status *stats) { static coffee_page_t skip_pages; static char last_pages_are_active; struct file_header hdr; coffee_page_t active, obsolete, free; coffee_page_t sector_start, sector_end; coffee_page_t page; memset(stats, 0, sizeof(*stats)); active = obsolete = free = 0; /* * get_sector_status() is an iterative function using local static * state. It therefore requires that the caller starts iterating from * sector 0 in order to reset the internal state. */ if(sector == 0) { skip_pages = 0; last_pages_are_active = 0; } sector_start = sector * COFFEE_PAGES_PER_SECTOR; sector_end = sector_start + COFFEE_PAGES_PER_SECTOR; /* * Account for pages belonging to a file starting in a previous * segment that extends into this segment. If the whole segment is * covered, we do not need to continue counting pages in this iteration. */ if(last_pages_are_active) { if(skip_pages >= COFFEE_PAGES_PER_SECTOR) { stats->active = COFFEE_PAGES_PER_SECTOR; skip_pages -= COFFEE_PAGES_PER_SECTOR; return 0; } active = skip_pages; } else { if(skip_pages >= COFFEE_PAGES_PER_SECTOR) { stats->obsolete = COFFEE_PAGES_PER_SECTOR; skip_pages -= COFFEE_PAGES_PER_SECTOR; return skip_pages >= COFFEE_PAGES_PER_SECTOR ? 0 : skip_pages; } obsolete = skip_pages; } /* Determine the amount of pages of each type that have not been accounted for yet in the current sector. */ for(page = sector_start + skip_pages; page < sector_end;) { read_header(&hdr, page); last_pages_are_active = 0; if(HDR_ACTIVE(hdr)) { last_pages_are_active = 1; page += hdr.max_pages; active += hdr.max_pages; } else if(HDR_ISOLATED(hdr)) { page++; obsolete++; } else if(HDR_OBSOLETE(hdr)) { page += hdr.max_pages; obsolete += hdr.max_pages; } else { free = sector_end - page; break; } } /* * Determine the amount of pages in the following sectors that * should be remembered for the next iteration. This is necessary * because no file page except the first contains information * about what type of page it is. A side effect of remembering this * amount is that there is no need to read in the headers of each * of these pages from the storage. */ skip_pages = active + obsolete + free - COFFEE_PAGES_PER_SECTOR; if(skip_pages > 0) { if(last_pages_are_active) { active = COFFEE_PAGES_PER_SECTOR - obsolete; } else { obsolete = COFFEE_PAGES_PER_SECTOR - active; } } stats->active = active; stats->obsolete = obsolete; stats->free = free; /* * To avoid unnecessary page isolation, we notify the caller that * "skip_pages" pages should be isolated only if the current file extent * ends in the next sector. If the file extent ends in a more distant * sector, however, the garbage collection can free the next sector * immediately without requiring page isolation. */ return (last_pages_are_active || (skip_pages >= COFFEE_PAGES_PER_SECTOR)) ? 0 : skip_pages; } /*---------------------------------------------------------------------------*/ static void isolate_pages(coffee_page_t start, coffee_page_t skip_pages) { struct file_header hdr; coffee_page_t page; /* Split an obsolete file starting in the previous sector and mark the following pages as isolated. */ memset(&hdr, 0, sizeof(hdr)); hdr.flags = HDR_FLAG_ALLOCATED | HDR_FLAG_ISOLATED; /* Isolation starts from the next sector. */ for(page = 0; page < skip_pages; page++) { write_header(&hdr, start + page); } PRINTF("Coffee: Isolated %u pages starting in sector %d\n", (unsigned)skip_pages, (int)start / COFFEE_PAGES_PER_SECTOR); } /*---------------------------------------------------------------------------*/ static void collect_garbage(int mode) { coffee_page_t sector; struct sector_status stats; coffee_page_t first_page, isolation_count; PRINTF("Coffee: Running the garbage collector in %s mode\n", mode == GC_RELUCTANT ? "reluctant" : "greedy"); /* * The garbage collector erases as many sectors as possible. A sector is * erasable if there are only free or obsolete pages in it. */ for(sector = 0; sector < COFFEE_SECTOR_COUNT; sector++) { isolation_count = get_sector_status(sector, &stats); PRINTF("Coffee: Sector %u has %u active, %u obsolete, and %u free pages.\n", (unsigned)sector, (unsigned)stats.active, (unsigned)stats.obsolete, (unsigned)stats.free); if(stats.active > 0) { continue; } if((mode == GC_RELUCTANT && stats.free == 0) || (mode == GC_GREEDY && stats.obsolete > 0)) { first_page = sector * COFFEE_PAGES_PER_SECTOR; if(first_page < next_free) { next_free = first_page; } if(isolation_count > 0) { isolate_pages(first_page + COFFEE_PAGES_PER_SECTOR, isolation_count); } COFFEE_ERASE(sector); PRINTF("Coffee: Erased sector %d!\n", sector); if(mode == GC_RELUCTANT && isolation_count > 0) { break; } } } } /*---------------------------------------------------------------------------*/ static coffee_page_t next_file(coffee_page_t page, struct file_header *hdr) { /* * The quick-skip algorithm for finding file extents is the most * essential part of Coffee. The file allocation rules enable this * algorithm to quickly jump over free areas and allocated extents * after reading single headers and determining their status. * * The worst-case performance occurs when we encounter multiple long * sequences of isolated pages, but such sequences are uncommon and * always shorter than a sector. */ if(HDR_FREE(*hdr)) { return (page + COFFEE_PAGES_PER_SECTOR) & ~(COFFEE_PAGES_PER_SECTOR - 1); } else if(HDR_ISOLATED(*hdr)) { return page + 1; } return page + hdr->max_pages; } /*---------------------------------------------------------------------------*/ static struct file * load_file(coffee_page_t start, struct file_header *hdr) { int i, unreferenced, free; struct file *file; /* * We prefer to overwrite a free slot since unreferenced ones * contain usable data. Free slots are designated by the page * value INVALID_PAGE. */ for(i = 0, unreferenced = free = -1; i < COFFEE_MAX_OPEN_FILES; i++) { if(FILE_FREE(&coffee_files[i])) { free = i; break; } else if(FILE_UNREFERENCED(&coffee_files[i])) { unreferenced = i; } } if(free == -1) { if(unreferenced != -1) { i = unreferenced; } else { return NULL; } } file = &coffee_files[i]; file->page = start; file->end = UNKNOWN_OFFSET; file->max_pages = hdr->max_pages; file->flags = HDR_MODIFIED(*hdr) ? COFFEE_FILE_MODIFIED : 0; /* We don't know the amount of records yet. */ file->record_count = -1; return file; } /*---------------------------------------------------------------------------*/ static struct file * find_file(const char *name) { int i; struct file_header hdr; coffee_page_t page; /* First check if the file metadata is cached. */ for(i = 0; i < COFFEE_MAX_OPEN_FILES; i++) { if(FILE_FREE(&coffee_files[i])) { continue; } read_header(&hdr, coffee_files[i].page); if(HDR_ACTIVE(hdr) && !HDR_LOG(hdr) && strcmp(name, hdr.name) == 0) { return &coffee_files[i]; } } /* Scan the flash memory sequentially otherwise. */ for(page = 0; page < COFFEE_PAGE_COUNT; page = next_file(page, &hdr)) { read_header(&hdr, page); if(HDR_ACTIVE(hdr) && !HDR_LOG(hdr) && strcmp(name, hdr.name) == 0) { return load_file(page, &hdr); } } return NULL; } /*---------------------------------------------------------------------------*/ static cfs_offset_t file_end(coffee_page_t start) { struct file_header hdr; unsigned char buf[COFFEE_PAGE_SIZE]; coffee_page_t page; int i; read_header(&hdr, start); /* * Move from the end of the range towards the beginning and look for * a byte that has been modified. * * An important implication of this is that if the last written bytes * are zeroes, then these are skipped from the calculation. */ for(page = hdr.max_pages - 1; page >= 0; page--) { COFFEE_READ(buf, sizeof(buf), (start + page) * COFFEE_PAGE_SIZE); for(i = COFFEE_PAGE_SIZE - 1; i >= 0; i--) { if(buf[i] != 0) { if(page == 0 && i < sizeof(hdr)) { return 0; } return 1 + i + (page * COFFEE_PAGE_SIZE) - sizeof(hdr); } } } /* All bytes are writable. */ return 0; } /*---------------------------------------------------------------------------*/ static coffee_page_t find_contiguous_pages(coffee_page_t amount) { coffee_page_t page, start; struct file_header hdr; start = INVALID_PAGE; for(page = next_free; page < COFFEE_PAGE_COUNT;) { read_header(&hdr, page); if(HDR_FREE(hdr)) { if(start == INVALID_PAGE) { start = page; if(start + amount >= COFFEE_PAGE_COUNT) { /* We can stop immediately if the remaining pages are not enough. */ break; } } /* All remaining pages in this sector are free -- jump to the next sector. */ page = next_file(page, &hdr); if(start + amount <= page) { if(start == next_free) { next_free = start + amount; } return start; } } else { start = INVALID_PAGE; page = next_file(page, &hdr); } } return INVALID_PAGE; } /*---------------------------------------------------------------------------*/ static int remove_by_page(coffee_page_t page, int remove_log, int close_fds, int gc_allowed) { struct file_header hdr; int i; read_header(&hdr, page); if(!HDR_ACTIVE(hdr)) { return -1; } if(remove_log && HDR_MODIFIED(hdr)) { if(remove_by_page(hdr.log_page, !REMOVE_LOG, !CLOSE_FDS, !ALLOW_GC) < 0) { return -1; } } hdr.flags |= HDR_FLAG_OBSOLETE; write_header(&hdr, page); gc_wait = 0; /* Close all file descriptors that reference the removed file. */ if(close_fds) { for(i = 0; i < COFFEE_FD_SET_SIZE; i++) { if(coffee_fd_set[i].file != NULL && coffee_fd_set[i].file->page == page) { coffee_fd_set[i].flags = COFFEE_FD_FREE; } } } for(i = 0; i < COFFEE_MAX_OPEN_FILES; i++) { if(coffee_files[i].page == page) { coffee_files[i].page = INVALID_PAGE; coffee_files[i].references = 0; coffee_files[i].max_pages = 0; } } if(!COFFEE_EXTENDED_WEAR_LEVELLING && gc_allowed) { collect_garbage(GC_RELUCTANT); } return 0; } /*---------------------------------------------------------------------------*/ static coffee_page_t page_count(cfs_offset_t size) { return (size + sizeof(struct file_header) + COFFEE_PAGE_SIZE - 1) / COFFEE_PAGE_SIZE; } /*---------------------------------------------------------------------------*/ static struct file * reserve(const char *name, coffee_page_t pages, int allow_duplicates, unsigned flags) { struct file_header hdr; coffee_page_t page; struct file *file; if(!allow_duplicates && find_file(name) != NULL) { return NULL; } page = find_contiguous_pages(pages); if(page == INVALID_PAGE) { if(gc_wait) { return NULL; } collect_garbage(GC_GREEDY); page = find_contiguous_pages(pages); if(page == INVALID_PAGE) { gc_wait = 1; return NULL; } } memset(&hdr, 0, sizeof(hdr)); strncpy(hdr.name, name, sizeof(hdr.name) - 1); hdr.max_pages = pages; hdr.flags = HDR_FLAG_ALLOCATED | flags; write_header(&hdr, page); PRINTF("Coffee: Reserved %u pages starting from %u for file %s\n", (unsigned)pages, (unsigned)page, name); file = load_file(page, &hdr); if(file != NULL) { file->end = 0; } return file; } /*---------------------------------------------------------------------------*/ #if COFFEE_MICRO_LOGS static void adjust_log_config(struct file_header *hdr, uint16_t *log_record_size, uint16_t *log_records) { *log_record_size = hdr->log_record_size == 0 ? COFFEE_PAGE_SIZE : hdr->log_record_size; *log_records = hdr->log_records == 0 ? COFFEE_LOG_SIZE / *log_record_size : hdr->log_records; } #endif /* COFFEE_MICRO_LOGS */ /*---------------------------------------------------------------------------*/ #if COFFEE_MICRO_LOGS static uint16_t modify_log_buffer(uint16_t log_record_size, cfs_offset_t *offset, uint16_t *size) { uint16_t region; region = *offset / log_record_size; *offset %= log_record_size; if(*size > log_record_size - *offset) { *size = log_record_size - *offset; } return region; } #endif /* COFFEE_MICRO_LOGS */ /*---------------------------------------------------------------------------*/ #if COFFEE_MICRO_LOGS static int get_record_index(coffee_page_t log_page, uint16_t search_records, uint16_t region) { cfs_offset_t base; uint16_t processed; uint16_t batch_size; int16_t match_index, i; base = absolute_offset(log_page, sizeof(uint16_t) * search_records); batch_size = search_records > COFFEE_LOG_TABLE_LIMIT ? COFFEE_LOG_TABLE_LIMIT : search_records; processed = 0; match_index = -1; { uint16_t indices[batch_size]; while(processed < search_records && match_index < 0) { if(batch_size + processed > search_records) { batch_size = search_records - processed; } base -= batch_size * sizeof(indices[0]); COFFEE_READ(&indices, sizeof(indices[0]) * batch_size, base); for(i = batch_size - 1; i >= 0; i--) { if(indices[i] - 1 == region) { match_index = search_records - processed - (batch_size - i); break; } } processed += batch_size; } } return match_index; } #endif /* COFFEE_MICRO_LOGS */ /*---------------------------------------------------------------------------*/ #if COFFEE_MICRO_LOGS static int read_log_page(struct file_header *hdr, int16_t record_count, struct log_param *lp) { uint16_t region; int16_t match_index; uint16_t log_record_size; uint16_t log_records; cfs_offset_t base; uint16_t search_records; adjust_log_config(hdr, &log_record_size, &log_records); region = modify_log_buffer(log_record_size, &lp->offset, &lp->size); search_records = record_count < 0 ? log_records : record_count; match_index = get_record_index(hdr->log_page, search_records, region); if(match_index < 0) { return -1; } base = absolute_offset(hdr->log_page, log_records * sizeof(region)); base += (cfs_offset_t)match_index * log_record_size; base += lp->offset; COFFEE_READ(lp->buf, lp->size, base); return lp->size; } #endif /* COFFEE_MICRO_LOGS */ /*---------------------------------------------------------------------------*/ #if COFFEE_MICRO_LOGS static coffee_page_t create_log(struct file *file, struct file_header *hdr) { uint16_t log_record_size, log_records; cfs_offset_t size; struct file *log_file; adjust_log_config(hdr, &log_record_size, &log_records); /* Log index size + log data size. */ size = log_records * (sizeof(uint16_t) + log_record_size); log_file = reserve(hdr->name, page_count(size), 1, HDR_FLAG_LOG); if(log_file == NULL) { return INVALID_PAGE; } hdr->flags |= HDR_FLAG_MODIFIED; hdr->log_page = log_file->page; write_header(hdr, file->page); file->flags |= COFFEE_FILE_MODIFIED; return log_file->page; } #endif /* COFFEE_MICRO_LOGS */ /*---------------------------------------------------------------------------*/ static int merge_log(coffee_page_t file_page, int extend) { struct file_header hdr, hdr2; int fd, n; cfs_offset_t offset; coffee_page_t max_pages; struct file *new_file; int i; read_header(&hdr, file_page); fd = cfs_open(hdr.name, CFS_READ); if(fd < 0) { return -1; } /* * The reservation function adds extra space for the header, which has * already been accounted for in the previous reservation. */ max_pages = hdr.max_pages << extend; new_file = reserve(hdr.name, max_pages, 1, 0); if(new_file == NULL) { cfs_close(fd); return -1; } offset = 0; do { char buf[hdr.log_record_size == 0 ? COFFEE_PAGE_SIZE : hdr.log_record_size]; n = cfs_read(fd, buf, sizeof(buf)); if(n < 0) { remove_by_page(new_file->page, !REMOVE_LOG, !CLOSE_FDS, ALLOW_GC); cfs_close(fd); return -1; } else if(n > 0) { COFFEE_WRITE(buf, n, absolute_offset(new_file->page, offset)); offset += n; } } while(n != 0); for(i = 0; i < COFFEE_FD_SET_SIZE; i++) { if(coffee_fd_set[i].flags != COFFEE_FD_FREE && coffee_fd_set[i].file->page == file_page) { coffee_fd_set[i].file = new_file; new_file->references++; } } if(remove_by_page(file_page, REMOVE_LOG, !CLOSE_FDS, !ALLOW_GC) < 0) { remove_by_page(new_file->page, !REMOVE_LOG, !CLOSE_FDS, !ALLOW_GC); cfs_close(fd); return -1; } /* Copy the log configuration. */ read_header(&hdr2, new_file->page); hdr2.log_record_size = hdr.log_record_size; hdr2.log_records = hdr.log_records; write_header(&hdr2, new_file->page); new_file->flags &= ~COFFEE_FILE_MODIFIED; new_file->end = offset; cfs_close(fd); return 0; } /*---------------------------------------------------------------------------*/ #if COFFEE_MICRO_LOGS static int find_next_record(struct file *file, coffee_page_t log_page, int log_records) { int log_record, preferred_batch_size; if(file->record_count >= 0) { return file->record_count; } preferred_batch_size = log_records > COFFEE_LOG_TABLE_LIMIT ? COFFEE_LOG_TABLE_LIMIT : log_records; { /* The next log record is unknown at this point; search for it. */ uint16_t indices[preferred_batch_size]; uint16_t processed; uint16_t batch_size; log_record = log_records; for(processed = 0; processed < log_records; processed += batch_size) { batch_size = log_records - processed >= preferred_batch_size ? preferred_batch_size : log_records - processed; COFFEE_READ(&indices, batch_size * sizeof(indices[0]), absolute_offset(log_page, processed * sizeof(indices[0]))); for(log_record = 0; log_record < batch_size; log_record++) { if(indices[log_record] == 0) { log_record += processed; break; } } } } return log_record; } #endif /* COFFEE_MICRO_LOGS */ /*---------------------------------------------------------------------------*/ #if COFFEE_MICRO_LOGS static int write_log_page(struct file *file, struct log_param *lp) { struct file_header hdr; uint16_t region; coffee_page_t log_page; int16_t log_record; uint16_t log_record_size; uint16_t log_records; cfs_offset_t offset; struct log_param lp_out; read_header(&hdr, file->page); adjust_log_config(&hdr, &log_record_size, &log_records); region = modify_log_buffer(log_record_size, &lp->offset, &lp->size); log_page = 0; if(HDR_MODIFIED(hdr)) { /* A log structure has already been created. */ log_page = hdr.log_page; log_record = find_next_record(file, log_page, log_records); if(log_record >= log_records) { /* The log is full; merge the log. */ PRINTF("Coffee: Merging the file %s with its log\n", hdr.name); return merge_log(file->page, 0); } } else { /* Create a log structure. */ log_page = create_log(file, &hdr); if(log_page == INVALID_PAGE) { return -1; } PRINTF("Coffee: Created a log structure for file %s at page %u\n", hdr.name, (unsigned)log_page); hdr.log_page = log_page; log_record = 0; } { char copy_buf[log_record_size]; lp_out.offset = offset = region * log_record_size; lp_out.buf = copy_buf; lp_out.size = log_record_size; if((lp->offset > 0 || lp->size != log_record_size) && read_log_page(&hdr, log_record, &lp_out) < 0) { COFFEE_READ(copy_buf, sizeof(copy_buf), absolute_offset(file->page, offset)); } memcpy(©_buf[lp->offset], lp->buf, lp->size); /* * Write the region number in the region index table. * The region number is incremented to avoid values of zero. */ offset = absolute_offset(log_page, 0); ++region; COFFEE_WRITE(®ion, sizeof(region), offset + log_record * sizeof(region)); offset += log_records * sizeof(region); COFFEE_WRITE(copy_buf, sizeof(copy_buf), offset + log_record * log_record_size); file->record_count = log_record + 1; } return lp->size; } #endif /* COFFEE_MICRO_LOGS */ /*---------------------------------------------------------------------------*/ static int get_available_fd(void) { int i; for(i = 0; i < COFFEE_FD_SET_SIZE; i++) { if(coffee_fd_set[i].flags == COFFEE_FD_FREE) { return i; } } return -1; } /*---------------------------------------------------------------------------*/ int cfs_open(const char *name, int flags) { int fd; struct file_desc *fdp; fd = get_available_fd(); if(fd < 0) { PRINTF("Coffee: Failed to allocate a new file descriptor!\n"); return -1; } fdp = &coffee_fd_set[fd]; fdp->flags = 0; fdp->io_flags = 0; fdp->file = find_file(name); if(fdp->file == NULL) { if((flags & (CFS_READ | CFS_WRITE)) == CFS_READ) { return -1; } fdp->file = reserve(name, page_count(COFFEE_DYN_SIZE), 1, 0); if(fdp->file == NULL) { return -1; } fdp->file->end = 0; } else if(fdp->file->end == UNKNOWN_OFFSET) { fdp->file->end = file_end(fdp->file->page); } fdp->flags |= flags; fdp->offset = flags & CFS_APPEND ? fdp->file->end : 0; fdp->file->references++; return fd; } /*---------------------------------------------------------------------------*/ void cfs_close(int fd) { if(FD_VALID(fd)) { coffee_fd_set[fd].flags = COFFEE_FD_FREE; coffee_fd_set[fd].file->references--; coffee_fd_set[fd].file = NULL; } } /*---------------------------------------------------------------------------*/ cfs_offset_t cfs_seek(int fd, cfs_offset_t offset, int whence) { struct file_desc *fdp; cfs_offset_t new_offset; if(!FD_VALID(fd)) { return -1; } fdp = &coffee_fd_set[fd]; if(whence == CFS_SEEK_SET) { new_offset = offset; } else if(whence == CFS_SEEK_END) { new_offset = fdp->file->end + offset; } else if(whence == CFS_SEEK_CUR) { new_offset = fdp->offset + offset; } else { return (cfs_offset_t)-1; } if(new_offset < 0 || new_offset > fdp->file->max_pages * COFFEE_PAGE_SIZE) { return -1; } if(fdp->file->end < new_offset) { if(FD_WRITABLE(fd)) { fdp->file->end = new_offset; } else { /* Disallow seeking past the end of the file for read only FDs */ return (cfs_offset_t)-1; } } return fdp->offset = new_offset; } /*---------------------------------------------------------------------------*/ int cfs_remove(const char *name) { struct file *file; /* * Coffee removes files by marking them as obsolete. The space * is not guaranteed to be reclaimed immediately, but must be * sweeped by the garbage collector. The garbage collector is * called once a file reservation request cannot be granted. */ file = find_file(name); if(file == NULL) { return -1; } return remove_by_page(file->page, REMOVE_LOG, CLOSE_FDS, ALLOW_GC); } /*---------------------------------------------------------------------------*/ int cfs_read(int fd, void *buf, unsigned size) { struct file_desc *fdp; struct file *file; #if COFFEE_MICRO_LOGS struct file_header hdr; struct log_param lp; unsigned bytes_left; int r; #endif if(!(FD_VALID(fd) && FD_READABLE(fd))) { return -1; } fdp = &coffee_fd_set[fd]; file = fdp->file; if(fdp->io_flags & CFS_COFFEE_IO_ENSURE_READ_LENGTH) { while(fdp->offset + size > file->end) { ((char *)buf)[--size] = '\0'; } } else if(fdp->offset + size > file->end) { size = file->end - fdp->offset; } /* If the file is not modified, read directly from the file extent. */ if(!FILE_MODIFIED(file)) { COFFEE_READ(buf, size, absolute_offset(file->page, fdp->offset)); fdp->offset += size; return size; } #if COFFEE_MICRO_LOGS read_header(&hdr, file->page); /* * Copy the contents of the most recent log record. If there is * no log record for the file area to read from, we simply read * from the original file extent. */ for(bytes_left = size; bytes_left > 0; bytes_left -= r) { lp.offset = fdp->offset; lp.buf = buf; lp.size = bytes_left; r = read_log_page(&hdr, file->record_count, &lp); /* Read from the original file if we cannot find the data in the log. */ if(r < 0) { COFFEE_READ(buf, lp.size, absolute_offset(file->page, fdp->offset)); r = lp.size; } fdp->offset += r; buf = (char *)buf + r; } #endif /* COFFEE_MICRO_LOGS */ return size; } /*---------------------------------------------------------------------------*/ int cfs_write(int fd, const void *buf, unsigned size) { struct file_desc *fdp; struct file *file; #if COFFEE_MICRO_LOGS int i; struct log_param lp; cfs_offset_t bytes_left; int8_t need_dummy_write; const char dummy[1] = { 0xff }; #endif if(!(FD_VALID(fd) && FD_WRITABLE(fd))) { return -1; } fdp = &coffee_fd_set[fd]; file = fdp->file; /* Attempt to extend the file if we try to write past the end. */ if(!(fdp->io_flags & CFS_COFFEE_IO_FIRM_SIZE)) { while(size + fdp->offset + sizeof(struct file_header) > (file->max_pages * COFFEE_PAGE_SIZE)) { if(merge_log(file->page, 1) < 0) { return -1; } file = fdp->file; PRINTF("Extended the file at page %u\n", (unsigned)file->page); } } #if COFFEE_MICRO_LOGS if(!(fdp->io_flags & CFS_COFFEE_IO_FLASH_AWARE) && (FILE_MODIFIED(file) || fdp->offset < file->end)) { need_dummy_write = 0; for(bytes_left = size; bytes_left > 0;) { lp.offset = fdp->offset; lp.buf = (void *)buf; lp.size = bytes_left; i = write_log_page(file, &lp); if(i < 0) { /* Return -1 if we wrote nothing because the log write failed. */ if(size == bytes_left) { return -1; } break; } else if(i == 0) { /* The file was merged with the log. */ file = fdp->file; } else { /* A log record was written. */ bytes_left -= i; fdp->offset += i; buf = (char *)buf + i; /* Update the file end for a potential log merge that might occur while writing log records. */ if(fdp->offset > file->end) { file->end = fdp->offset; need_dummy_write = 1; } } } if(need_dummy_write) { /* * A log record has been written at an offset beyond the original * extent's end. Consequently, we need to write a dummy value at the * corresponding end offset in the original extent to ensure that * the correct file size is calculated when opening the file again. */ COFFEE_WRITE(dummy, 1, absolute_offset(file->page, fdp->offset - 1)); } } else { #endif /* COFFEE_MICRO_LOGS */ if(COFFEE_APPEND_ONLY && fdp->offset < file->end) { return -1; } COFFEE_WRITE(buf, size, absolute_offset(file->page, fdp->offset)); fdp->offset += size; #if COFFEE_MICRO_LOGS } #endif /* COFFEE_MICRO_LOGS */ if(fdp->offset > file->end) { file->end = fdp->offset; } return size; } /*---------------------------------------------------------------------------*/ int cfs_opendir(struct cfs_dir *dir, const char *name) { /* * Coffee is only guaranteed to support the directory names "/" and ".", * but it does not enforce this currently. */ memset(dir->state, 0, sizeof(coffee_page_t)); return 0; } /*---------------------------------------------------------------------------*/ int cfs_readdir(struct cfs_dir *dir, struct cfs_dirent *record) { struct file_header hdr; coffee_page_t page; coffee_page_t next_page; memcpy(&page, dir->state, sizeof(coffee_page_t)); while(page < COFFEE_PAGE_COUNT) { read_header(&hdr, page); if(HDR_ACTIVE(hdr) && !HDR_LOG(hdr)) { memcpy(record->name, hdr.name, sizeof(record->name)); record->name[sizeof(record->name) - 1] = '\0'; record->size = file_end(page); next_page = next_file(page, &hdr); memcpy(dir->state, &next_page, sizeof(coffee_page_t)); return 0; } page = next_file(page, &hdr); } return -1; } /*---------------------------------------------------------------------------*/ void cfs_closedir(struct cfs_dir *dir) { return; } /*---------------------------------------------------------------------------*/ int cfs_coffee_reserve(const char *name, cfs_offset_t size) { return reserve(name, page_count(size), 0, 0) == NULL ? -1 : 0; } /*---------------------------------------------------------------------------*/ int cfs_coffee_configure_log(const char *filename, unsigned log_size, unsigned log_record_size) { struct file *file; struct file_header hdr; if(log_record_size == 0 || log_record_size > COFFEE_PAGE_SIZE || log_size < log_record_size) { return -1; } file = find_file(filename); if(file == NULL) { return -1; } read_header(&hdr, file->page); if(HDR_MODIFIED(hdr)) { /* Too late to customize the log. */ return -1; } hdr.log_records = log_size / log_record_size; hdr.log_record_size = log_record_size; write_header(&hdr, file->page); return 0; } /*---------------------------------------------------------------------------*/ int cfs_coffee_set_io_semantics(int fd, unsigned flags) { if(!FD_VALID(fd)) { return -1; } coffee_fd_set[fd].io_flags |= flags; return 0; } /*---------------------------------------------------------------------------*/ int cfs_coffee_format(void) { coffee_page_t i; PRINTF("Coffee: Formatting %u sectors", (unsigned)COFFEE_SECTOR_COUNT); for(i = 0; i < COFFEE_SECTOR_COUNT; i++) { COFFEE_ERASE(i); PRINTF("."); } /* Formatting invalidates the file information. */ memset(&coffee_files, 0, sizeof(coffee_files)); memset(&coffee_fd_set, 0, sizeof(coffee_fd_set)); next_free = 0; gc_wait = 1; PRINTF(" done!\n"); return 0; } /*---------------------------------------------------------------------------*/