4 * This file is part of BeRTOS.
6 * Bertos is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
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12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
16 * You should have received a copy of the GNU General Public License
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18 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
20 * As a special exception, you may use this file as part of a free software
21 * library without restriction. Specifically, if other files instantiate
22 * templates or use macros or inline functions from this file, or you compile
23 * this file and link it with other files to produce an executable, this
24 * file does not by itself cause the resulting executable to be covered by
25 * the GNU General Public License. This exception does not however
26 * invalidate any other reasons why the executable file might be covered by
27 * the GNU General Public License.
29 * Copyright 2007 Develer S.r.l. (http://www.develer.com/)
33 * \brief BattFS: a filesystem for embedded platforms (implementation).
37 * \author Francesco Sacchi <batt@develer.com>
43 #include <cfg/debug.h>
44 #include <cfg/macros.h> /* MIN, MAX */
45 #include <cpu/byteorder.h> /* cpu_to_xx */
47 #define LOG_LEVEL LOG_LVL_INFO
48 #define LOG_FORMAT LOG_FMT_VERBOSE
51 #include <string.h> /* memset, memmove */
55 * Convert from memory representation to disk structure.
56 * \note filesystem is in little-endian format.
58 INLINE void battfs_to_disk(struct BattFsPageHeader *hdr, uint8_t *buf)
60 STATIC_ASSERT(BATTFS_HEADER_LEN == 12);
64 buf[2] = hdr->fill >> 8;
67 buf[4] = hdr->pgoff >> 8;
70 * Sequence number is 40 bits long.
71 * No need to take care of wraparonds: the memory will die first!
74 buf[6] = hdr->seq >> 8;
75 buf[7] = hdr->seq >> 16;
76 buf[8] = hdr->seq >> 24;
77 buf[9] = hdr->seq >> 32;
80 * This field must be the last one!
81 * This is needed because if the page is only partially
82 * written, we can use this to detect it.
85 buf[11] = hdr->fcs >> 8;
89 * Convert from disk structure to memory representation.
90 * \note filesystem is in little-endian format.
92 INLINE void disk_to_battfs(uint8_t *buf, struct BattFsPageHeader *hdr)
94 STATIC_ASSERT(BATTFS_HEADER_LEN == 12);
96 hdr->fill = buf[2] << 8 | buf[1];
97 hdr->pgoff = buf[4] << 8 | buf[3];
98 hdr->seq = (seq_t)buf[9] << 32 | (seq_t)buf[8] << 24 | (seq_t)buf[7] << 16 | buf[6] << 8 | buf[5];
99 hdr->fcs = buf[11] << 8 | buf[10];
103 * Compute the fcs of the header.
105 static fcs_t computeFcs(struct BattFsPageHeader *hdr)
107 uint8_t buf[BATTFS_HEADER_LEN];
110 battfs_to_disk(hdr, buf);
112 /* fcs is at the end of whole header */
113 rotating_update(buf, BATTFS_HEADER_LEN - sizeof(fcs_t), &cks);
119 * Read header of page \a page.
120 * \return true on success, false otherwise.
122 static bool battfs_readHeader(struct BattFsSuper *disk, pgcnt_t page, struct BattFsPageHeader *hdr)
124 uint8_t buf[BATTFS_HEADER_LEN];
126 * Read header from disk.
127 * Header is actually a footer, and so
128 * resides at page end.
130 if (disk->read(disk, page, disk->page_size - BATTFS_HEADER_LEN, buf, BATTFS_HEADER_LEN)
131 != BATTFS_HEADER_LEN)
133 LOG_ERR("Error: page[%d]\n", page);
138 disk_to_battfs(buf, hdr);
144 * Write header of page \a page.
145 * \return true on success, false otherwise.
147 static bool battfs_writeHeader(struct BattFsSuper *disk, pgcnt_t page, struct BattFsPageHeader *hdr)
149 uint8_t buf[BATTFS_HEADER_LEN];
152 battfs_to_disk(hdr, buf);
155 * write header to disk.
156 * Header is actually a footer, and so
157 * resides at page end.
159 if (disk->write(disk, page, disk->page_size - BATTFS_HEADER_LEN, buf, BATTFS_HEADER_LEN)
160 != BATTFS_HEADER_LEN)
162 LOG_ERR("Error: page[%d]\n", page);
169 * Count the number of pages from
170 * inode 0 to \a inode in \a filelen_table.
172 static pgcnt_t countPages(pgoff_t *filelen_table, inode_t inode)
176 for (inode_t i = 0; i < inode; i++)
177 cnt += filelen_table[i];
183 * Move all pages in page allocation array from \a src to \a src + \a offset.
184 * The number of pages moved is page_count - MAX(dst, src).
186 static void movePages(struct BattFsSuper *disk, pgcnt_t src, int offset)
188 pgcnt_t dst = src + offset;
189 memmove(&disk->page_array[dst], &disk->page_array[src], (disk->page_count - MAX(dst, src)) * sizeof(pgcnt_t));
193 /* Fill empty space in array with sentinel */
194 for (pgcnt_t page = disk->page_count + offset; page < disk->page_count; page++)
195 disk->page_array[page] = PAGE_UNSET_SENTINEL;
200 * Count number of pages per file on \a disk.
201 * This information is registered in \a filelen_table.
202 * Array index represent file inode, while value contained
203 * is the number of pages used by that file.
205 * \return true if ok, false on disk read errors.
206 * \note The whole disk is scanned once.
208 static bool countDiskFilePages(struct BattFsSuper *disk, pgoff_t *filelen_table)
210 BattFsPageHeader hdr;
211 disk->free_page_start = 0;
213 /* Count the number of disk page per file */
214 for (pgcnt_t page = 0; page < disk->page_count; page++)
216 if (!battfs_readHeader(disk, page, &hdr))
219 /* Increase free space */
220 disk->free_bytes += disk->page_size - BATTFS_HEADER_LEN;
222 /* Check header FCS */
223 if (hdr.fcs == computeFcs(&hdr))
225 ASSERT(hdr.fill <= disk->page_size - BATTFS_HEADER_LEN);
227 /* Page is valid and is owned by a file */
228 filelen_table[hdr.inode]++;
230 /* Keep trace of free space */
231 disk->free_bytes -= hdr.fill;
232 disk->free_page_start++;
235 LOG_INFO("free_bytes:%d, free_page_start:%d\n", disk->free_bytes, disk->free_page_start);
241 * Fill page allocation array of \a disk
242 * using file lenghts in \a filelen_table.
244 * The page allocation array is an array containings all file infos.
245 * Is ordered by file, and within each file is ordered by page offset
247 * e.g. : at page array[0] you will find page address of the first page
248 * of the first file (if present).
249 * Free blocks are allocated after the last file, starting from invalid ones
250 * and continuing with the marked free ones.
252 * \return true if ok, false on disk read errors.
253 * \note The whole disk is scanned once.
255 static bool fillPageArray(struct BattFsSuper *disk, pgoff_t *filelen_table)
257 BattFsPageHeader hdr;
258 pgcnt_t curr_free_page = disk->free_page_start;
259 /* Fill page allocation array */
260 for (pgcnt_t page = 0; page < disk->page_count; page++)
262 if (!battfs_readHeader(disk, page, &hdr))
265 /* Check header FCS */
266 if (hdr.fcs == computeFcs(&hdr))
268 /* Compute array position */
269 pgcnt_t array_pos = countPages(filelen_table, hdr.inode);
270 array_pos += hdr.pgoff;
273 /* Check if position is already used by another page of the same file */
274 if (disk->page_array[array_pos] == PAGE_UNSET_SENTINEL)
275 disk->page_array[array_pos] = page;
278 BattFsPageHeader hdr_prv;
280 if (!battfs_readHeader(disk, disk->page_array[array_pos], &hdr_prv))
283 /* Check header FCS */
284 ASSERT(hdr_prv.fcs == computeFcs(&hdr_prv));
286 /* Only the very same page with a different seq number can be here */
287 ASSERT(hdr.inode == hdr_prv.inode);
288 ASSERT(hdr.pgoff == hdr_prv.pgoff);
289 ASSERT(hdr.seq != hdr_prv.seq);
291 pgcnt_t new_page, old_page;
295 * Sequence number comparison: since
296 * seq is 40 bits wide, it wraps once
297 * every 1.1E12 times.
298 * The memory will not live enough to
299 * see a wraparound, so we can use a simple
302 if (hdr.seq > hdr_prv.seq)
304 /* Current header is newer than the previuos one */
305 old_page = disk->page_array[array_pos];
307 old_fill = hdr_prv.fill;
311 /* Previous header is newer than the current one */
313 new_page = disk->page_array[array_pos];
318 disk->page_array[array_pos] = new_page;
320 disk->free_bytes += old_fill;
321 /* Shift all array one position to the left, overwriting duplicate page */
322 array_pos -= hdr.pgoff;
323 array_pos += filelen_table[hdr.inode];
324 movePages(disk, array_pos, -1);
325 /* Move back all indexes */
326 filelen_table[hdr.inode]--;
327 disk->free_page_start--;
329 /* Set old page as free */
330 ASSERT(disk->page_array[curr_free_page] == PAGE_UNSET_SENTINEL);
331 disk->page_array[curr_free_page++] = old_page;
337 /* Invalid page, keep as free */
338 ASSERT(disk->page_array[curr_free_page] == PAGE_UNSET_SENTINEL);
339 LOG_INFO("Page %d invalid, keeping as free\n", page);
340 disk->page_array[curr_free_page++] = page;
347 * Initialize and mount disk described by
349 * \return false on errors, true otherwise.
351 bool battfs_init(struct BattFsSuper *disk)
353 pgoff_t filelen_table[BATTFS_MAX_FILES];
358 /* Init disk device */
359 if (!disk->open(disk))
361 LOG_ERR("open error\n");
365 /* Disk open must set all of these */
370 ASSERT(disk->page_size);
371 ASSERT(disk->page_count);
372 ASSERT(disk->page_count < PAGE_UNSET_SENTINEL - 1);
373 ASSERT(disk->page_array);
375 memset(filelen_table, 0, BATTFS_MAX_FILES * sizeof(pgoff_t));
377 disk->free_bytes = 0;
378 disk->disk_size = (disk_size_t)(disk->page_size - BATTFS_HEADER_LEN) * disk->page_count;
380 /* Count pages per file */
381 if (!countDiskFilePages(disk, filelen_table))
383 LOG_ERR("error counting file pages\n");
387 /* Once here, we have filelen_table filled with file lengths */
389 /* Fill page array with sentinel */
390 for (pgcnt_t page = 0; page < disk->page_count; page++)
391 disk->page_array[page] = PAGE_UNSET_SENTINEL;
393 /* Fill page allocation array using filelen_table */
394 if (!fillPageArray(disk, filelen_table))
396 LOG_ERR("error filling page array\n");
400 /* Init list for opened files. */
401 LIST_INIT(&disk->file_opened_list);
407 * \return 0 if ok, EOF on errors.
409 static int battfs_flush(struct KFile *fd)
418 * \return 0 if ok, EOF on errors.
420 static int battfs_fileclose(struct KFile *fd)
422 BattFs *fdb = BATTFS_CAST(fd);
430 * Read from file \a fd \a size bytes in \a buf.
431 * \return The number of bytes read.
433 static size_t battfs_read(struct KFile *fd, void *_buf, size_t size)
435 BattFs *fdb = BATTFS_CAST(fd);
436 uint8_t *buf = (uint8_t *)_buf;
438 size_t total_read = 0;
440 pgaddr_t addr_offset;
443 size = MIN((kfile_off_t)size, fd->size - fd->seek_pos);
447 pg_offset = fd->seek_pos / (fdb->disk->page_size - BATTFS_HEADER_LEN);
448 addr_offset = fd->seek_pos % (fdb->disk->page_size - BATTFS_HEADER_LEN);
449 read_len = MIN(size, (size_t)(fdb->disk->page_size - BATTFS_HEADER_LEN - addr_offset));
452 if (fdb->disk->read(fdb->disk, fdb->start[pg_offset], addr_offset, buf, read_len) != read_len)
454 #warning TODO set error?
458 fd->seek_pos += read_len;
459 total_read += read_len;
467 * Search file \a inode in \a disk using a binary search.
468 * \return pointer to file start in disk->page_array
469 * if file exists, NULL otherwise.
471 static pgcnt_t *findFile(BattFsSuper *disk, inode_t inode)
473 BattFsPageHeader hdr;
474 pgcnt_t first = 0, page, last = disk->page_count -1;
477 while (first <= last)
479 page = (first + last) / 2;
481 if (!battfs_readHeader(disk, disk->page_array[page], &hdr))
484 fcs = computeFcs(&hdr);
485 if (hdr.fcs == fcs && hdr.inode == inode)
486 return (&disk->page_array[page]) - hdr.pgoff;
487 else if (hdr.fcs == fcs && hdr.inode < inode)
497 * \return true if file \a inode exists on \a disk, false otherwise.
499 bool battfs_fileExists(BattFsSuper *disk, inode_t inode)
501 return findFile(disk, inode) != NULL;
505 * Count size of file \a inode on \a disk, starting at pointer \a start
506 * in disk->page_array. Size is written in \a size.
507 * \return true if all s ok, false on disk read errors.
509 static bool countFileSize(BattFsSuper *disk, pgcnt_t *start, inode_t inode, file_size_t *size)
512 BattFsPageHeader hdr;
516 if (!battfs_readHeader(disk, *start++, &hdr))
518 if (hdr.fcs == computeFcs(&hdr) && hdr.inode == inode)
526 * Open file \a inode from \a disk in \a mode.
527 * File context is stored in \a fd.
528 * \return true if ok, false otherwise.
530 bool battfs_fileopen(BattFsSuper *disk, BattFs *fd, inode_t inode, filemode_t mode)
534 memset(fd, 0, sizeof(*fd));
536 /* Search file start point in disk page array */
537 fd->start = findFile(disk, inode);
538 if (fd->start == NULL)
540 if (!(mode & BATTFS_CREATE))
543 /* File does not exist, create it */
544 BattFsPageHeader hdr;
549 hdr.fcs = computeFcs(&hdr);
550 #warning TODO: get a free block and write on disk!
554 if (!countFileSize(disk, fd->start, inode, &fd->fd.size))
557 /* Reset seek position */
560 /* Insert file handle in list, ordered by inode, ascending. */
561 FOREACH_NODE(n, &disk->file_opened_list)
563 BattFs *file = containerof(n, BattFs, link);
564 if (file->inode >= inode)
567 INSERT_BEFORE(&fd->link, n);
574 fd->fd.close = battfs_fileclose;
575 fd->fd.flush = battfs_flush;
576 fd->fd.read = battfs_read;
577 fd->fd.reopen = kfile_genericReopen;
578 fd->fd.seek = kfile_genericSeek;
580 #warning TODO battfs_write, battfs_error, battfs_clearerr
582 fd->fd.write = battfs_write;
583 fd->fd.error = battfs_error;
584 fd->fd.clearerr = battfs_clearerr;
587 DB(fd->fd._type = KFT_BATTFS);
595 bool battfs_close(struct BattFsSuper *disk)
600 /* Close all open files */
601 FOREACH_NODE(n, &disk->file_opened_list)
603 BattFs *file = containerof(n, BattFs, link);
604 res += battfs_fileclose(&file->fd);
608 return disk->close(disk) && (res == 0);
611 bool battfs_writeTestBlock(struct BattFsSuper *disk, pgcnt_t page, inode_t inode, seq_t seq, fill_t fill, pgoff_t pgoff)
613 BattFsPageHeader hdr;
619 hdr.fcs = computeFcs(&hdr);
621 if (!battfs_writeHeader(disk, page, &hdr))
623 LOG_ERR("error writing hdr\n");