bsd/hfs/hfs_btreeio.c

96 OSStatus GetBTreeBlock(FileReference vp, u_int32_t blockNum, GetBlockOptions options, BlockDescriptor *block)
102 	/* If the btree block is being read using hint, it is
115         offset = (daddr64_t)blockNum * (daddr64_t)block->blockSize;
116         bp = buf_getblk(vp, (daddr64_t)blockNum, block->blockSize, 0, 0, BLK_META);
118             VNOP_BLOCKMAP(vp, offset, block->blockSize, &blkno, NULL, NULL, 0, NULL) == 0) {
122         retval = buf_meta_bread(vp, (daddr64_t)blockNum, block->blockSize, NOCRED, &bp);
128         block->blockHeader = bp;
129         block->buffer = (char *)buf_dataptr(bp);
130     	block->blockNum = buf_lblkno(bp);
131         block->blockReadFromDisk = (buf_fromcache(bp) == 0);	/* not found in cache ==> came from disk */
134 		block->isModified = 0;
136         /* Check and endian swap B-Tree node (only if it's a valid block) */
139             if ((((BTNodeDescriptor *)block->buffer)->kind == kBTHeaderNode) &&
140                 (((BTHeaderRec *)((char *)block->buffer + 14))->nodeSize != buf_count(bp)) &&
141                 (SWAP_BE16 (((BTHeaderRec *)((char *)block->buffer + 14))->nodeSize) != buf_count(bp))) {
146                  * size once the B-tree control block is set up with the node size
149                 retval = hfs_swap_BTNode (block, vp, kSwapBTNodeHeaderRecordOnly, allow_empty_node);
151 			} else if (block->blockReadFromDisk) {
156                 retval = hfs_swap_BTNode (block, vp, kSwapBTNodeBigToHost, allow_empty_node);
157             } else if (*((u_int16_t *)((char *)block->buffer + (block->blockSize - sizeof (u_int16_t)))) == 0x0e00) {
163                 retval = hfs_swap_BTNode (block, vp, kSwapBTNodeBigToHost, allow_empty_node);
181         block->blockHeader = NULL;
182         block->buffer = NULL;
214     BlockDescriptor block;
216     /* Prepare the block pointer */
217     block.blockHeader = bp;
218     block.buffer = (char *)buf_dataptr(bp);
219     block.blockNum = buf_lblkno(bp);
221     block.blockReadFromDisk = (buf_fromcache(bp) == 0);
222     block.blockSize = buf_count(bp);
228     retval = hfs_swap_BTNode (&block, vp, kSwapBTNodeHostToBig, true);
304              * Delay-write this block.
328 			// on this block and if so, abort it (which will call buf_brelse()).
332 				//          journal and blowing away a block that has
402 	 * the allocation block size is less than the b-tree node
683 	 * Set up Attribute B-tree control block