battfs_to_disk(hdr, buf);
rotating_init(&cks);
/* fcs is at the end of whole header */
- rotating_update(buf,BATTFS_HEADER_LEN - sizeof(fcs_t), &cks);
+ rotating_update(buf, BATTFS_HEADER_LEN - sizeof(fcs_t), &cks);
return cks;
}
battfs_to_disk(hdr, buf);
rotating_init(&cks);
/* fcs_free is just before fcs of whole header */
- rotating_update(buf,BATTFS_HEADER_LEN - 2 * sizeof(fcs_t), &cks);
+ rotating_update(buf, BATTFS_HEADER_LEN - 2 * sizeof(fcs_t), &cks);
return cks;
}
}
/**
- * Insert \a page into page allocation array of \a disk, using \a filelen_table and
- * \a free_number to compute position.
+ * Insert \a page into page allocation array of \a disk,
+ * using \a mark to compute position.
*/
static void insertFreePage(struct BattFsSuper *disk, mark_t mark, pgcnt_t page)
{
}
}
-
/**
- * Initialize and mount disk described by
- * \a d.
- * \return false on errors, true otherwise.
+ * Determine free_start and free_next blocks for \a disk
+ * using \a minl, \a maxl, \a minh, \a maxh.
+ *
+ * Mark_t is a type that has at least 1 bit more than
+ * pgaddr_t. So all free blocks can be numbered unsing
+ * at most half numbers of an mark_t type.
+ * The free blocks algorith increments by 1 the disk->free_next
+ * every time a page becomes free. So the free block sequence is
+ * guaranteed to be countiguous.
+ * Only wrap arounds may happen, but due to half size sequence limitation,
+ * there are only 4 possible situations:
+ *
+ * \verbatim
+ * |------lower half------|-------upper half-------|
+ *
+ * 1) |------minl*****maxl---|------------------------|
+ * 2) |------minl********maxl|minh******maxh----------|
+ * 3) |----------------------|----minh*******maxh-----|
+ * 4) |minl******maxl--------|------------minh****maxh|
+ * \endverbatim
+ *
+ * Situations 1 and 3 are easy to detect, while 2 and 4 require more care.
*/
-bool battfs_init(struct BattFsSuper *disk)
+static void findFreeStartNext(struct BattFsSuper *disk, mark_t minl, mark_t maxl, mark_t minh, mark_t maxh)
{
- BattFsPageHeader hdr;
- pgoff_t filelen_table[BATTFS_MAX_FILES];
- mark_t minl, maxl, minh, maxh;
-
- /* Sanity check */
- ASSERT(disk->open);
+ /* Determine free_start & free_next */
+ if (maxl >= minl)
+ {
+ /* Valid interval found in lower half */
+ if (maxh >= minh)
+ {
+ /* Valid interval also found in upper half */
+ if (maxl == minh - 1)
+ {
+ /* Interval starts in lower half and end in upper */
+ disk->free_start = minl;
+ disk->free_next = maxh;
+ }
+ else
+ {
+ /* Interval starts in upper half and end in lower */
+ ASSERT(minl == 0);
+ ASSERT(maxh == (MAX_PAGE_ADDR | MARK_HALF_SIZE));
- /* Init disk device */
- if (!disk->open(disk))
+ disk->free_start = minh;
+ disk->free_next = maxl;
+ }
+ }
+ else
+ {
+ /*
+ * Upper interval is invalid.
+ * Use lower values.
+ */
+
+ disk->free_start = minl;
+ disk->free_next = maxl;
+ }
+ }
+ else if (maxh >= minh)
{
- TRACEMSG("open error\n");
- return false;
+ /*
+ * Lower interval is invalid.
+ * Use upper values.
+ */
+ disk->free_start = minh;
+ disk->free_next = maxh;
+ }
+ else
+ {
+ /*
+ * No valid interval found.
+ * Hopefully the disk is brand new.
+ */
+ TRACEMSG("No valid marked free block found, new disk?\n");
+ disk->free_start = 0;
+ disk->free_next = -1; //to be incremented ahead
}
- /* Disk open must set all of these */
- ASSERT(disk->read);
- ASSERT(disk->write);
- ASSERT(disk->erase);
- ASSERT(disk->close);
- ASSERT(disk->page_size);
- ASSERT(disk->page_count);
- ASSERT(disk->page_count < PAGE_UNSET_SENTINEL - 1);
- ASSERT(disk->page_array);
+ /* free_next should contain the first usable address */
+ disk->free_next++;
- memset(filelen_table, 0, BATTFS_MAX_FILES * sizeof(pgoff_t));
+ TRACEMSG("Free markers:\n minl %u\n maxl %u\n minh %u\n maxh %u\n free_start %u\n free_next %u\n",
+ minl, maxl, minh, maxh, disk->free_start, disk->free_next);
+}
+
+/**
+ * Count number of pages per file on \a disk.
+ * This information is registered in \a filelen_table.
+ * Array index represent file inode, while value contained
+ * is the number of pages used by that file.
+ *
+ * \return true if ok, false on disk read errors.
+ * \note The whole disk is scanned once.
+ */
+static bool countDiskFilePages(struct BattFsSuper *disk, pgoff_t *filelen_table)
+{
+ BattFsPageHeader hdr;
+ mark_t minl, maxl, minh, maxh;
/* Initialize min and max counters to keep trace od free blocks */
minl = MAX_PAGE_ADDR;
minh = MAX_PAGE_ADDR | MARK_HALF_SIZE;
maxh = 0 | MARK_HALF_SIZE;
- disk->free_bytes = 0;
- disk->disk_size = (disk_size_t)(disk->page_size - BATTFS_HEADER_LEN) * disk->page_count;
/* Count the number of disk page per file */
for (pgcnt_t page = 0; page < disk->page_count; page++)
TRACEMSG("page [%d] invalid, keeping as free\n", page);
}
}
+ findFreeStartNext(disk, minl, maxl, minh, maxh);
+ return true;
+}
- /* Once here, we have filelen_table filled with file lengths */
-
- /* Fill page array with sentinel */
- for (pgcnt_t page = 0; page < disk->page_count; page++)
- disk->page_array[page] = PAGE_UNSET_SENTINEL;
-
- /* Determine free_start & free_next */
- if (maxl >= minl)
- {
- if (maxh >= minh)
- {
- if (maxl == minh - 1)
- {
- disk->free_start = minl;
- disk->free_next = maxh;
- }
- else
- {
- ASSERT(minl == 0);
- ASSERT(maxh == (MAX_PAGE_ADDR | MARK_HALF_SIZE));
-
- disk->free_start = minh;
- disk->free_next = maxl;
- }
- }
- else
- {
- disk->free_start = minl;
- disk->free_next = maxl;
- }
- }
- else if (maxh >= minh)
- {
- disk->free_start = minh;
- disk->free_next = maxh;
- }
- else
- {
- TRACEMSG("No valid marked free block found\n");
- disk->free_start = 0;
- disk->free_next = -1; //to be incremented ahead
- }
-
- /* free_next should contain the first usable address */
- disk->free_next++;
-
- TRACEMSG("Free markers:\n minl %u\n maxl %u\n minh %u\n maxh %u\n free_start %u\n free_next %u\n",
- minl, maxl, minh, maxh, disk->free_start, disk->free_next);
-
-
+/**
+ * Fill page allocation array of \a disk
+ * using file lenghts in \a filelen_table.
+ *
+ * The page allocation array is an array containings all files info.
+ * Is ordered by file, and within each file is ordered by page offset
+ * inside file.
+ * e.g. : at page array[0] you will find page address of the first page
+ * of the first file (if present).
+ * Free blocks are allocated after the last file starting from invalid ones
+ * and continuing with the marked free ones.
+ *
+ * \return true if ok, false on disk read errors.
+ * \note The whole disk is scanned once.
+ */
+static bool fillPageArray(struct BattFsSuper *disk, pgoff_t *filelen_table)
+{
+ BattFsPageHeader hdr;
/* Fill page allocation array */
for (pgcnt_t page = 0; page < disk->page_count; page++)
{
insertFreePage(disk, hdr.mark, page);
}
}
+ return true;
+}
+
+/**
+ * Initialize and mount disk described by
+ * \a disk.
+ * \return false on errors, true otherwise.
+ */
+bool battfs_init(struct BattFsSuper *disk)
+{
+ pgoff_t filelen_table[BATTFS_MAX_FILES];
+
+ /* Sanity check */
+ ASSERT(disk->open);
+
+ /* Init disk device */
+ if (!disk->open(disk))
+ {
+ TRACEMSG("open error\n");
+ return false;
+ }
+
+ /* Disk open must set all of these */
+ ASSERT(disk->read);
+ ASSERT(disk->write);
+ ASSERT(disk->erase);
+ ASSERT(disk->close);
+ ASSERT(disk->page_size);
+ ASSERT(disk->page_count);
+ ASSERT(disk->page_count < PAGE_UNSET_SENTINEL - 1);
+ ASSERT(disk->page_array);
+
+ memset(filelen_table, 0, BATTFS_MAX_FILES * sizeof(pgoff_t));
+
+ disk->free_bytes = 0;
+ disk->disk_size = (disk_size_t)(disk->page_size - BATTFS_HEADER_LEN) * disk->page_count;
+
+ /* Count pages per file */
+ if (!countDiskFilePages(disk, filelen_table))
+ {
+ TRACEMSG("error counting file pages\n");
+ return false;
+ }
+
+ /* Once here, we have filelen_table filled with file lengths */
+
+ /* Fill page array with sentinel */
+ for (pgcnt_t page = 0; page < disk->page_count; page++)
+ disk->page_array[page] = PAGE_UNSET_SENTINEL;
+
+ /* Fill page allocation array using filelen_table */
+ if (!fillPageArray(disk, filelen_table))
+ {
+ TRACEMSG("error filling page array\n");
+ return false;
+ }
- #warning Test me!
return true;
}
projects / bertos.git / commitdiff