xnu-2050.7.9.tar.gz

[apple/xnu.git] / bsd / vfs / vfs_cache.c

diff --git a/bsd/vfs/vfs_cache.c b/bsd/vfs/vfs_cache.c
index 3096d12941242a58deaa997d4d735b7d6af68b37..73fbb3afb3f0942f1db5cb6e386c9bd1f9214775 100644 (file)
--- a/bsd/vfs/vfs_cache.c
+++ b/bsd/vfs/vfs_cache.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2000-2008 Apple Inc. All rights reserved.
+ * Copyright (c) 2000-2012 Apple Inc. All rights reserved.
  *
  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
  * 
@@ -192,6 +192,11 @@ static unsigned int crc32tab[256];
  * If BUILDPATH_NO_FS_ENTER is set in flags, it only uses values present
  * in the name cache and does not enter the file system.
  *
+ * If BUILDPATH_CHECK_MOVED is set in flags, we return EAGAIN when 
+ * we encounter ENOENT during path reconstruction.  ENOENT means that 
+ * one of the parents moved while we were building the path.  The 
+ * caller can special handle this case by calling build_path again.
+ *
  * passed in vp must have a valid io_count reference
  */
 int
@@ -309,7 +314,8 @@ again:
                 * Walk up the parent chain.
                 */
                if (((vp->v_parent != NULLVP) && !fixhardlink) ||
-                   (flags & BUILDPATH_NO_FS_ENTER)) {
+                               (flags & BUILDPATH_NO_FS_ENTER)) {
+
                        /*
                         * In this if () block we are not allowed to enter the filesystem
                         * to conclusively get the most accurate parent identifier.
@@ -323,17 +329,17 @@ again:
 
                                /* The code below will exit early if 'tvp = vp' == NULL */
                        }
-
                        vp = vp->v_parent;
-                       
+
                        /*
                         * if the vnode we have in hand isn't a directory and it
                         * has a v_parent, then we started with the resource fork
                         * so skip up to avoid getting a duplicate copy of the
                         * file name in the path.
                         */
-                       if (vp && !vnode_isdir(vp) && vp->v_parent)
+                       if (vp && !vnode_isdir(vp) && vp->v_parent) {
                                vp = vp->v_parent;
+                       }
                } else {
                        /*
                         * No parent, go get it if supported.
@@ -492,6 +498,14 @@ out:
         */
        *outlen = &buff[buflen] - end;
  
+       /* One of the parents was moved during path reconstruction. 
+        * The caller is interested in knowing whether any of the 
+        * parents moved via BUILDPATH_CHECK_MOVED, so return EAGAIN.
+        */
+       if ((ret == ENOENT) && (flags & BUILDPATH_CHECK_MOVED)) {
+               ret = EAGAIN;
+       }
+
        return (ret);
 }