svn commit: r353065 - head/sys/fs/tmpfs

Konstantin Belousov kib at FreeBSD.org
Thu Oct 3 19:55:06 UTC 2019


Author: kib
Date: Thu Oct  3 19:55:05 2019
New Revision: 353065
URL: https://svnweb.freebsd.org/changeset/base/353065

Log:
  tmpfs_readdir(): unlock the locked node.
  
  During readdir() we guarantee that the tn_dir.tn_parent does not go
  away, but it might be replaced by a parallel rename.  Read tn_parent
  only once, then use the cached value.
  
  Reported and tested by:	pho
  Sponsored by:	The FreeBSD Foundation
  MFC after:	1 week

Modified:
  head/sys/fs/tmpfs/tmpfs_subr.c

Modified: head/sys/fs/tmpfs/tmpfs_subr.c
==============================================================================
--- head/sys/fs/tmpfs/tmpfs_subr.c	Thu Oct  3 19:51:56 2019	(r353064)
+++ head/sys/fs/tmpfs/tmpfs_subr.c	Thu Oct  3 19:55:05 2019	(r353065)
@@ -1147,8 +1147,9 @@ static int
 tmpfs_dir_getdotdotdent(struct tmpfs_mount *tm, struct tmpfs_node *node,
     struct uio *uio)
 {
-	int error;
+	struct tmpfs_node *parent;
 	struct dirent dent;
+	int error;
 
 	TMPFS_VALIDATE_DIR(node);
 	MPASS(uio->uio_offset == TMPFS_DIRCOOKIE_DOTDOT);
@@ -1157,12 +1158,13 @@ tmpfs_dir_getdotdotdent(struct tmpfs_mount *tm, struct
 	 * Return ENOENT if the current node is already removed.
 	 */
 	TMPFS_ASSERT_LOCKED(node);
-	if (node->tn_dir.tn_parent == NULL)
+	parent = node->tn_dir.tn_parent;
+	if (parent == NULL)
 		return (ENOENT);
 
-	TMPFS_NODE_LOCK(node->tn_dir.tn_parent);
-	dent.d_fileno = node->tn_dir.tn_parent->tn_id;
-	TMPFS_NODE_UNLOCK(node->tn_dir.tn_parent);
+	TMPFS_NODE_LOCK(parent);
+	dent.d_fileno = parent->tn_id;
+	TMPFS_NODE_UNLOCK(parent);
 
 	dent.d_type = DT_DIR;
 	dent.d_namlen = 2;


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