]> git.saurik.com Git - apple/xnu.git/blobdiff - bsd/hfs/hfs_btreeio.c
xnu-2422.115.4.tar.gz
[apple/xnu.git] / bsd / hfs / hfs_btreeio.c
index 7e5182cd9996c82bd7f3fae46d712db108660021..5fc36da9511f9c1abf9c0da991942ca1791b257d 100644 (file)
@@ -50,7 +50,7 @@
 /* From bsd/vfs/vfs_bio.c */
 extern int bdwrite_internal(struct buf *, int);
 
-static int ClearBTNodes(struct vnode *vp, long blksize, off_t offset, off_t amount);
+static int ClearBTNodes(struct vnode *vp, int blksize, off_t offset, off_t amount);
 static int btree_journal_modify_block_end(struct hfsmount *hfsmp, struct buf *bp);
 
 void btree_swap_node(struct buf *bp, __unused void *arg);
@@ -133,47 +133,72 @@ OSStatus GetBTreeBlock(FileReference vp, u_int32_t blockNum, GetBlockOptions opt
                // XXXdbg 
                block->isModified = 0;
 
-        /* Check and endian swap B-Tree node (only if it's a valid block) */
-        if (!(options & kGetEmptyBlock)) {
-            /* This happens when we first open the b-tree, we might not have all the node data on hand */
-            if ((((BTNodeDescriptor *)block->buffer)->kind == kBTHeaderNode) &&
-                (((BTHeaderRec *)((char *)block->buffer + 14))->nodeSize != buf_count(bp)) &&
-                (SWAP_BE16 (((BTHeaderRec *)((char *)block->buffer + 14))->nodeSize) != buf_count(bp))) {
+               /* Check and endian swap B-Tree node (only if it's a valid block) */
+               if (!(options & kGetEmptyBlock)) {
+
+                       /* This happens when we first open the b-tree, we might not have all the node data on hand */
+                       if ((((BTNodeDescriptor *)block->buffer)->kind == kBTHeaderNode) &&
+                                       (((BTHeaderRec *)((char *)block->buffer + 14))->nodeSize != buf_count(bp)) &&
+                                       (SWAP_BE16 (((BTHeaderRec *)((char *)block->buffer + 14))->nodeSize) != buf_count(bp))) {
 
-                /*
-                 * Don't swap the node descriptor, record offsets, or other records.
-                 * This record will be invalidated and re-read with the correct node
-                 * size once the B-tree control block is set up with the node size
-                 * from the header record.
-                 */
-                retval = hfs_swap_BTNode (block, vp, kSwapBTNodeHeaderRecordOnly, allow_empty_node);
-
-                       } else if (block->blockReadFromDisk) {
-               /*
-                * The node was just read from disk, so always swap/check it.
-                * This is necessary on big endian since the test below won't trigger.
-                */
-                retval = hfs_swap_BTNode (block, vp, kSwapBTNodeBigToHost, allow_empty_node);
-            } else if (*((u_int16_t *)((char *)block->buffer + (block->blockSize - sizeof (u_int16_t)))) == 0x0e00) {
                                /*
-                                * The node was left in the cache in non-native order, so swap it.
-                                * This only happens on little endian, after the node is written
-                                * back to disk.
+                                * Don't swap the node descriptor, record offsets, or other records.
+                                * This record will be invalidated and re-read with the correct node
+                                * size once the B-tree control block is set up with the node size
+                                * from the header record.
                                 */
-                retval = hfs_swap_BTNode (block, vp, kSwapBTNodeBigToHost, allow_empty_node);
-            }
-            
-               /*
-                * If we got an error, then the node is only partially swapped.
-                * We mark the buffer invalid so that the next attempt to get the
-                * node will read it and attempt to swap again, and will notice
-                * the error again.  If we didn't do this, the next attempt to get
-                * the node might use the partially swapped node as-is.
-                */
-            if (retval)
+                               retval = hfs_swap_BTNode (block, vp, kSwapBTNodeHeaderRecordOnly, allow_empty_node);
+
+                       } else {
+                               /*
+                                * In this case, we have enough data in-hand to do basic validation
+                                * on the B-Tree node.
+                                */
+                               if (block->blockReadFromDisk) {
+                                       /*
+                                        * The node was just read from disk, so always swap/check it.
+                                        * This is necessary on big endian since the test below won't trigger.
+                                        */
+                                       retval = hfs_swap_BTNode (block, vp, kSwapBTNodeBigToHost, allow_empty_node);
+                               } 
+                               else {
+                                       /*
+                                        * Block wasn't read from disk; it was found in the cache.  
+                                        */
+                                       if (*((u_int16_t *)((char *)block->buffer + (block->blockSize - sizeof (u_int16_t)))) == 0x0e00) {
+                                               /*
+                                                * The node was left in the cache in non-native order, so swap it.
+                                                * This only happens on little endian, after the node is written
+                                                * back to disk.
+                                                */
+                                               retval = hfs_swap_BTNode (block, vp, kSwapBTNodeBigToHost, allow_empty_node);
+                                       }
+                                       else if (*((u_int16_t *)((char *)block->buffer + (block->blockSize - sizeof (u_int16_t)))) == 0x000e) {
+                                               /*
+                                                * The node was in-cache in native-endianness.  We don't need to do 
+                                                * anything here, because the node is ready to use.  Set retval == 0.
+                                                */
+                                               retval = 0;
+                                       }
+                                       /*
+                                        * If the node doesn't have hex 14 (0xe) in the last two bytes of the buffer, 
+                                        * it doesn't necessarily mean that this is a bad node.  Zeroed nodes that are
+                                        * marked as unused in the b-tree map node would be OK and not have valid content.
+                                        */
+                               }
+                       }
+
+                       /*
+                        * If we got an error, then the node is only partially swapped.
+                        * We mark the buffer invalid so that the next attempt to get the
+                        * node will read it and attempt to swap again, and will notice
+                        * the error again.  If we didn't do this, the next attempt to get
+                        * the node might use the partially swapped node as-is.
+                        */
+                       if (retval)
                                buf_markinvalid(bp);
-        }
-    }
+               }
+       }
     
     if (retval) {
        if (bp)
@@ -549,7 +574,7 @@ out:
  * Clear out (zero) new b-tree nodes on disk.
  */
 static int
-ClearBTNodes(struct vnode *vp, long blksize, off_t offset, off_t amount)
+ClearBTNodes(struct vnode *vp, int blksize, off_t offset, off_t amount)
 {
        struct hfsmount *hfsmp = VTOHFS(vp);
        struct buf *bp = NULL;
@@ -635,7 +660,7 @@ again:
        /*
         * Serialize creation using HFS_CREATING_BTREE flag.
         */
-       lck_mtx_lock(&hfsmp->hfs_mutex);
+       hfs_lock_mount (hfsmp);
        if (hfsmp->hfs_flags & HFS_CREATING_BTREE) {
                        /* Someone else beat us, wait for them to finish. */
                        (void) msleep(hfsmp->hfs_attribute_cp, &hfsmp->hfs_mutex,
@@ -646,7 +671,7 @@ again:
                        goto again;
        }
        hfsmp->hfs_flags |= HFS_CREATING_BTREE;
-       lck_mtx_unlock(&hfsmp->hfs_mutex);
+       hfs_unlock_mount (hfsmp);
 
        /* Check if were out of usable disk space. */
        if ((hfs_freeblks(hfsmp, 1) == 0)) {
@@ -859,10 +884,10 @@ again:
        }
        
        /* Update vp/cp for attribute btree */
-       lck_mtx_lock(&hfsmp->hfs_mutex);
+       hfs_lock_mount (hfsmp);
        hfsmp->hfs_attribute_cp = VTOC(vp);
        hfsmp->hfs_attribute_vp = vp;
-       lck_mtx_unlock(&hfsmp->hfs_mutex);
+       hfs_unlock_mount (hfsmp);
 
        (void) hfs_flushvolumeheader(hfsmp, MNT_WAIT, HFS_ALTFLUSH);
 
@@ -874,7 +899,7 @@ again:
        /* Initialize the vnode for virtual attribute data file */
        result = init_attrdata_vnode(hfsmp);
        if (result) {
-               printf("hfs_create_attr_btree: init_attrdata_vnode() error=%d\n", result); 
+               printf("hfs_create_attr_btree: vol=%s init_attrdata_vnode() error=%d\n", hfsmp->vcbVN, result); 
        }
 
 exit:
@@ -897,10 +922,10 @@ exit:
        /*
         * All done, clear HFS_CREATING_BTREE, and wake up any sleepers.
         */
-       lck_mtx_lock(&hfsmp->hfs_mutex);
+       hfs_lock_mount (hfsmp);
        hfsmp->hfs_flags &= ~HFS_CREATING_BTREE;
        wakeup((caddr_t)hfsmp->hfs_attribute_cp);
-       lck_mtx_unlock(&hfsmp->hfs_mutex);
+       hfs_unlock_mount (hfsmp);
 
        return (result);
 }