/** * Writes the specified data block to a suitable location in flash. * * @param disk_block Points to the disk block to write. * @param data The contents of the data block. * @param out_area_idx On success, contains the index of the area * written to. * @param out_area_offset On success, contains the offset within the area * written to. * * @return 0 on success; nonzero on failure. */ int nffs_block_write_disk(const struct nffs_disk_block *disk_block, const void *data, uint8_t *out_area_idx, uint32_t *out_area_offset) { uint32_t area_offset; uint8_t area_idx; int rc; rc = nffs_misc_reserve_space(sizeof *disk_block + disk_block->ndb_data_len, &area_idx, &area_offset); if (rc != 0) { return rc; } rc = nffs_flash_write(area_idx, area_offset, disk_block, sizeof *disk_block); if (rc != 0) { return rc; } if (disk_block->ndb_data_len > 0) { rc = nffs_flash_write(area_idx, area_offset + sizeof *disk_block, data, disk_block->ndb_data_len); if (rc != 0) { return rc; } } *out_area_idx = area_idx; *out_area_offset = area_offset; ASSERT_IF_TEST(nffs_crc_disk_block_validate(disk_block, area_idx, area_offset) == 0); return 0; }
/** * Moves a chain of blocks from one area to another. This function attempts to * collate the blocks into a single new block in the destination area. * * @param last_entry The last block entry in the chain. * @param data_len The total length of data to collate. * @param to_area_idx The index of the area to copy to. * @param inout_next This parameter is only necessary if you are * calling this function during an iteration * of the entire hash table; pass null * otherwise. * On input, this points to the next hash entry * you plan on processing. * On output, this points to the next hash entry * that should be processed. * * @return 0 on success; * FS_ENOMEM if there is insufficient heap; * other nonzero on failure. */ static int nffs_gc_block_chain_collate(struct nffs_hash_entry *last_entry, uint32_t data_len, uint8_t to_area_idx, struct nffs_hash_entry **inout_next) { struct nffs_disk_block disk_block; struct nffs_hash_entry *entry; struct nffs_area *to_area; struct nffs_block last_block; struct nffs_block block; uint32_t to_area_offset; uint32_t from_area_offset; uint32_t data_offset; uint8_t *data; uint8_t from_area_idx; int rc; memset(&last_block, 0, sizeof last_block); data = malloc(data_len); if (data == NULL) { rc = FS_ENOMEM; goto done; } memset(&last_block, 0, sizeof(last_block)); to_area = nffs_areas + to_area_idx; entry = last_entry; data_offset = data_len; while (data_offset > 0) { rc = nffs_block_from_hash_entry(&block, entry); if (rc != 0) { goto done; } data_offset -= block.nb_data_len; nffs_flash_loc_expand(block.nb_hash_entry->nhe_flash_loc, &from_area_idx, &from_area_offset); from_area_offset += sizeof disk_block; STATS_INC(nffs_stats, nffs_readcnt_gccollate); rc = nffs_flash_read(from_area_idx, from_area_offset, data + data_offset, block.nb_data_len); if (rc != 0) { goto done; } if (entry != last_entry) { if (inout_next != NULL && *inout_next == entry) { *inout_next = SLIST_NEXT(entry, nhe_next); } nffs_block_delete_from_ram(entry); } else { last_block = block; } entry = block.nb_prev; } /* we had better have found the last block */ assert(last_block.nb_hash_entry); /* The resulting block should inherit its ID from its last constituent * block (this is the ID referenced by the parent inode and subsequent data * block). The previous ID gets inherited from the first constituent * block. */ memset(&disk_block, 0, sizeof disk_block); disk_block.ndb_id = last_block.nb_hash_entry->nhe_id; disk_block.ndb_seq = last_block.nb_seq + 1; disk_block.ndb_inode_id = last_block.nb_inode_entry->nie_hash_entry.nhe_id; if (entry == NULL) { disk_block.ndb_prev_id = NFFS_ID_NONE; } else { disk_block.ndb_prev_id = entry->nhe_id; } disk_block.ndb_data_len = data_len; nffs_crc_disk_block_fill(&disk_block, data); to_area_offset = to_area->na_cur; rc = nffs_flash_write(to_area_idx, to_area_offset, &disk_block, sizeof disk_block); if (rc != 0) { goto done; } rc = nffs_flash_write(to_area_idx, to_area_offset + sizeof disk_block, data, data_len); if (rc != 0) { goto done; } last_entry->nhe_flash_loc = nffs_flash_loc(to_area_idx, to_area_offset); rc = 0; ASSERT_IF_TEST(nffs_crc_disk_block_validate(&disk_block, to_area_idx, to_area_offset) == 0); done: free(data); return rc; }
/** * Moves a chain of blocks from one area to another. This function attempts to * collate the blocks into a single new block in the destination area. * * @param last_entry The last block entry in the chain. * @param data_len The total length of data to collate. * @param to_area_idx The index of the area to copy to. * @param inout_next This parameter is only necessary if you are * calling this function during an iteration * of the entire hash table; pass null * otherwise. * On input, this points to the next hash entry * you plan on processing. * On output, this points to the next hash entry * that should be processed. * * @return 0 on success; * FS_ENOMEM if there is insufficient heap; * other nonzero on failure. */ static int nffs_gc_block_chain_collate(struct nffs_hash_entry *last_entry, uint32_t data_len, uint8_t to_area_idx, struct nffs_hash_entry **inout_next) { struct nffs_disk_block disk_block; struct nffs_hash_entry *entry; struct nffs_area *to_area; struct nffs_block block; uint32_t to_area_offset; uint32_t from_area_offset; uint32_t data_offset; uint8_t *data; uint8_t from_area_idx; int rc; data = malloc(data_len); if (data == NULL) { rc = FS_ENOMEM; goto done; } to_area = nffs_areas + to_area_idx; entry = last_entry; data_offset = data_len; while (data_offset > 0) { rc = nffs_block_from_hash_entry(&block, entry); if (rc != 0) { goto done; } data_offset -= block.nb_data_len; nffs_flash_loc_expand(block.nb_hash_entry->nhe_flash_loc, &from_area_idx, &from_area_offset); from_area_offset += sizeof disk_block; rc = nffs_flash_read(from_area_idx, from_area_offset, data + data_offset, block.nb_data_len); if (rc != 0) { goto done; } if (entry != last_entry) { if (inout_next != NULL && *inout_next == entry) { *inout_next = SLIST_NEXT(entry, nhe_next); } nffs_block_delete_from_ram(entry); } entry = block.nb_prev; } memset(&disk_block, 0, sizeof disk_block); disk_block.ndb_magic = NFFS_BLOCK_MAGIC; disk_block.ndb_id = block.nb_hash_entry->nhe_id; disk_block.ndb_seq = block.nb_seq + 1; disk_block.ndb_inode_id = block.nb_inode_entry->nie_hash_entry.nhe_id; if (entry == NULL) { disk_block.ndb_prev_id = NFFS_ID_NONE; } else { disk_block.ndb_prev_id = entry->nhe_id; } disk_block.ndb_data_len = data_len; nffs_crc_disk_block_fill(&disk_block, data); to_area_offset = to_area->na_cur; rc = nffs_flash_write(to_area_idx, to_area_offset, &disk_block, sizeof disk_block); if (rc != 0) { goto done; } rc = nffs_flash_write(to_area_idx, to_area_offset + sizeof disk_block, data, data_len); if (rc != 0) { goto done; } last_entry->nhe_flash_loc = nffs_flash_loc(to_area_idx, to_area_offset); rc = 0; ASSERT_IF_TEST(nffs_crc_disk_block_validate(&disk_block, to_area_idx, to_area_offset) == 0); done: free(data); return rc; }
/** * Overwrites an existing data block. The resulting block has the same ID as * the old one, but it supersedes it with a greater sequence number. * * @param entry The data block to overwrite. * @param left_copy_len The number of bytes of existing data to retain * before the new data begins. * @param new_data The new data to write to the block. * @param new_data_len The number of new bytes to write to the block. * If this value plus left_copy_len is less * than the existing block's data length, * previous data at the end of the block is * retained. * * @return 0 on success; nonzero on failure. */ static int nffs_write_over_block(struct nffs_hash_entry *entry, uint16_t left_copy_len, const void *new_data, uint16_t new_data_len) { struct nffs_disk_block disk_block; struct nffs_block block; uint32_t src_area_offset; uint32_t dst_area_offset; uint16_t right_copy_len; uint16_t block_off; uint8_t src_area_idx; uint8_t dst_area_idx; int rc; rc = nffs_block_from_hash_entry(&block, entry); if (rc != 0) { return rc; } assert(left_copy_len <= block.nb_data_len); /* Determine how much old data at the end of the block needs to be * retained. If the new data doesn't extend to the end of the block, the * the rest of the block retains its old contents. */ if (left_copy_len + new_data_len > block.nb_data_len) { right_copy_len = 0; } else { right_copy_len = block.nb_data_len - left_copy_len - new_data_len; } block.nb_seq++; block.nb_data_len = left_copy_len + new_data_len + right_copy_len; nffs_block_to_disk(&block, &disk_block); nffs_flash_loc_expand(entry->nhe_flash_loc, &src_area_idx, &src_area_offset); rc = nffs_write_fill_crc16_overwrite(&disk_block, src_area_idx, src_area_offset, left_copy_len, right_copy_len, new_data, new_data_len); if (rc != 0) { return rc; } rc = nffs_misc_reserve_space(sizeof disk_block + disk_block.ndb_data_len, &dst_area_idx, &dst_area_offset); if (rc != 0) { return rc; } block_off = 0; /* Write the block header. */ rc = nffs_flash_write(dst_area_idx, dst_area_offset + block_off, &disk_block, sizeof disk_block); if (rc != 0) { return rc; } block_off += sizeof disk_block; /* Copy data from the start of the old block, in case the new data starts * at a non-zero offset. */ if (left_copy_len > 0) { rc = nffs_flash_copy(src_area_idx, src_area_offset + block_off, dst_area_idx, dst_area_offset + block_off, left_copy_len); if (rc != 0) { return rc; } block_off += left_copy_len; } /* Write the new data into the data block. This may extend the block's * length beyond its old value. */ rc = nffs_flash_write(dst_area_idx, dst_area_offset + block_off, new_data, new_data_len); if (rc != 0) { return rc; } block_off += new_data_len; /* Copy data from the end of the old block, in case the new data doesn't * extend to the end of the block. */ if (right_copy_len > 0) { rc = nffs_flash_copy(src_area_idx, src_area_offset + block_off, dst_area_idx, dst_area_offset + block_off, right_copy_len); if (rc != 0) { return rc; } block_off += right_copy_len; } assert(block_off == sizeof disk_block + block.nb_data_len); entry->nhe_flash_loc = nffs_flash_loc(dst_area_idx, dst_area_offset); ASSERT_IF_TEST(nffs_crc_disk_block_validate(&disk_block, dst_area_idx, dst_area_offset) == 0); return 0; }
/** * Populates the nffs RAM state with the memory representation of the specified * disk data block. * * @param disk_block The source disk block to insert. * @param area_idx The ID of the area containing the block. * @param area_offset The area_offset within the area of the block. * * @return 0 on success; nonzero on failure. */ static int nffs_restore_block(const struct nffs_disk_block *disk_block, uint8_t area_idx, uint32_t area_offset) { struct nffs_inode_entry *inode_entry; struct nffs_hash_entry *entry; struct nffs_block block; int do_replace; int new_block; int rc; new_block = 0; /* Check the block's CRC. If the block is corrupt, discard it. If this * block would have superseded another, the old block becomes current. */ rc = nffs_crc_disk_block_validate(disk_block, area_idx, area_offset); if (rc != 0) { goto err; } entry = nffs_hash_find_block(disk_block->ndb_id); if (entry != NULL) { rc = nffs_block_from_hash_entry_no_ptrs(&block, entry); if (rc != 0) { goto err; } rc = nffs_restore_block_gets_replaced(&block, disk_block, &do_replace); if (rc != 0) { goto err; } if (!do_replace) { /* The new block is superseded by the old; nothing to do. */ return 0; } nffs_block_delete_from_ram(entry); } entry = nffs_block_entry_alloc(); if (entry == NULL) { rc = FS_ENOMEM; goto err; } new_block = 1; entry->nhe_id = disk_block->ndb_id; entry->nhe_flash_loc = nffs_flash_loc(area_idx, area_offset); /* The block is ready to be inserted into the hash. */ inode_entry = nffs_hash_find_inode(disk_block->ndb_inode_id); if (inode_entry == NULL) { rc = nffs_restore_dummy_inode(disk_block->ndb_inode_id, &inode_entry); if (rc != 0) { goto err; } } if (inode_entry->nie_last_block_entry == NULL || inode_entry->nie_last_block_entry->nhe_id == disk_block->ndb_prev_id) { inode_entry->nie_last_block_entry = entry; } nffs_hash_insert(entry); if (disk_block->ndb_id >= nffs_hash_next_block_id) { nffs_hash_next_block_id = disk_block->ndb_id + 1; } /* Make sure the maximum block data size is not set lower than the size of * an existing block. */ if (disk_block->ndb_data_len > nffs_restore_largest_block_data_len) { nffs_restore_largest_block_data_len = disk_block->ndb_data_len; } return 0; err: if (new_block) { nffs_block_entry_free(entry); } return rc; }
/** * Populates the nffs RAM state with the memory representation of the specified * disk data block. * * @param disk_block The source disk block to insert. * @param area_idx The ID of the area containing the block. * @param area_offset The area_offset within the area of the block. * * @return 0 on success; nonzero on failure. */ static int nffs_restore_block(const struct nffs_disk_block *disk_block, uint8_t area_idx, uint32_t area_offset) { struct nffs_inode_entry *inode_entry; struct nffs_hash_entry *entry; struct nffs_block block; int do_replace; int new_block; int rc; new_block = 0; /* Check the block's CRC. If the block is corrupt, discard it. If this * block would have superseded another, the old block becomes current. */ rc = nffs_crc_disk_block_validate(disk_block, area_idx, area_offset); if (rc != 0) { goto err; } entry = nffs_hash_find_block(disk_block->ndb_id); if (entry != NULL) { rc = nffs_block_from_hash_entry_no_ptrs(&block, entry); if (rc != 0 && rc != FS_ENOENT) { goto err; } /* * If the old block reference is for a 'dummy' block, it was added * because the owning inode's lastblock was not yet restored. * Update the block hash entry and inode to reference the entry. */ if (nffs_block_is_dummy(entry)) { assert(entry->nhe_id == disk_block->ndb_id); /* * Entry is no longer dummy as it references the correct location */ entry->nhe_flash_loc = nffs_flash_loc(area_idx, area_offset); inode_entry = nffs_hash_find_inode(disk_block->ndb_inode_id); /* * Turn off flags in previously restored inode recording the * allocation of a dummy block */ if (inode_entry) { nffs_inode_unsetflags(inode_entry, NFFS_INODE_FLAG_DUMMYLSTBLK); } } rc = nffs_restore_block_gets_replaced(&block, disk_block, &do_replace); if (rc != 0) { goto err; } if (!do_replace) { /* The new block is superseded by the old; nothing to do. */ return 0; } /* * update the existing hash entry to reference the new flash location */ entry->nhe_flash_loc = nffs_flash_loc(area_idx, area_offset); } else { entry = nffs_block_entry_alloc(); if (entry == NULL) { rc = FS_ENOMEM; goto err; } new_block = 1; entry->nhe_id = disk_block->ndb_id; entry->nhe_flash_loc = nffs_flash_loc(area_idx, area_offset); /* The block is ready to be inserted into the hash. */ nffs_hash_insert(entry); if (disk_block->ndb_id >= nffs_hash_next_block_id) { nffs_hash_next_block_id = disk_block->ndb_id + 1; } } /* Make sure the maximum block data size is not set lower than the size of * an existing block. */ if (disk_block->ndb_data_len > nffs_restore_largest_block_data_len) { nffs_restore_largest_block_data_len = disk_block->ndb_data_len; } NFFS_LOG(DEBUG, "restoring block; id=0x%08x seq=%u inode_id=%u prev_id=%u " "data_len=%u\n", (unsigned int)disk_block->ndb_id, (unsigned int)disk_block->ndb_seq, (unsigned int)disk_block->ndb_inode_id, (unsigned int)disk_block->ndb_prev_id, disk_block->ndb_data_len); inode_entry = nffs_hash_find_inode(disk_block->ndb_inode_id); if (inode_entry == NULL) { /* * Owning inode not yet restored. * Allocate a dummy inode which temporarily owns this block. * It is not yet linked to a parent. */ rc = nffs_restore_dummy_inode(disk_block->ndb_inode_id, &inode_entry); if (rc != 0) { goto err; } /* * Record that this inode was created because a block was restored * before the inode */ nffs_inode_setflags(inode_entry, NFFS_INODE_FLAG_DUMMYINOBLK); inode_entry->nie_last_block_entry = entry; } else { if (nffs_inode_getflags(inode_entry, NFFS_INODE_FLAG_DELETED)) { /* * don't restore blocks for deleted inodes */ rc = FS_ENOENT; goto err; } } return 0; err: if (new_block) { nffs_hash_remove(entry); nffs_block_entry_free(entry); } return rc; }