xnu-1699.22.73.tar.gz

[apple/xnu.git] / bsd / hfs / hfscommon / BTree / BTreeAllocate.c

diff --git a/bsd/hfs/hfscommon/BTree/BTreeAllocate.c b/bsd/hfs/hfscommon/BTree/BTreeAllocate.c
index 99d586408da2425df6fc365de6c9f5f0beecd042..fe2f917143eaf71c23b69762f10cd66971fb26a1 100644 (file)
--- a/bsd/hfs/hfscommon/BTree/BTreeAllocate.c
+++ b/bsd/hfs/hfscommon/BTree/BTreeAllocate.c
@@ -621,7 +621,6 @@ Routine:    BTZeroUnusedNodes
 
 Function:      Write zeros to all nodes in the B-tree that are not currently in use.
 -------------------------------------------------------------------------------*/
-__private_extern__
 int
 BTZeroUnusedNodes(FCB *filePtr)
 {
@@ -695,31 +694,39 @@ BTZeroUnusedNodes(FCB *filePtr)
                                                err = EIO;
                                                goto ErrorExit;
                                        }
-                                       
+
                                        if (buf_flags(bp) & B_LOCKED) {
                                                /* 
-                                                * This node is already part of a transaction and will be
-                                                * written when the transaction is committed so don't write it here.
-                                                * If we did, then we'd hit a panic in hfs_vnop_bwrite since
-                                                * B_LOCKED is still set
+                                                * This node is already part of a transaction and will be written when
+                                                * the transaction is committed, so don't write it here.  If we did, then
+                                                * we'd hit a panic in hfs_vnop_bwrite because the B_LOCKED bit is still set.
                                                 */
                                                buf_brelse(bp);
                                                continue;
                                        }
-
                                        
                                        buf_clear(bp);
                                        buf_markaged(bp);
                                        
                                        /*
                                         * Try not to hog the buffer cache.  Wait for the write
-                                        * every 32 nodes.
+                                        * every 32 nodes.   If VNOP_BWRITE reports an error, bail out and bubble
+                                        * it up to the function calling us.  If we tried to update a read-only 
+                                        * mount on read-only media, for example, catching the error will let 
+                                        * us alert the callers of this function that they should maintain 
+                                        * the mount in read-only mode.
+
                                         */
                                        ++numWritten;
-                                       if (numWritten % 32 == 0)
-                                               VNOP_BWRITE(bp);
-                                       else
+                                       if (numWritten % 32 == 0) {
+                                               err = VNOP_BWRITE(bp);
+                                               if (err) {
+                                                       goto ErrorExit;
+                                               }
+                                       }
+                                       else {
                                                buf_bawrite(bp);
+                                       }
                                }
                        }