tar: --dereference consistency

[chaz/tar] / NEWS

diff --git a/NEWS b/NEWS
index b305f26a27348edb86cf13b53980b832d5cfa5c0..1484c555a8fafecab89d8a63bc3ffbbf0e5ceef5 100644 (file)
--- a/NEWS
+++ b/NEWS
@@ -1,4 +1,4 @@
-GNU tar NEWS - User visible changes. 2010-09-06
+GNU tar NEWS - User visible changes. 2010-09-23
 Please send GNU tar bug reports to <bug-tar@gnu.org>
 
 \f
@@ -14,10 +14,40 @@ time stamps to the full resolution.
 ** More reliable directory traversal when creating archives
 
 Tar now checks for inconsistencies caused when a file system is
-modified while tar is creating an archive.  The new checks are
-implemented via the openat, fstatat, and readlinkat calls standardized
-by POSIX.1-2008.  On an older system that lacks these calls, tar
-emulates them at some cost in efficiency and reliability.
+modified while tar is creating an archive.  In the new approach, tar
+maintains a cache of file descriptors to directories, so it uses more
+file descriptors than before, but it adjusts to system limits on
+the number of file descriptors.  Tar also takes more care when
+a file system is modified while tar is extracting from an archive.
+
+The new checks are implemented via the openat and related calls
+standardized by POSIX.1-2008.  On an older system where these calls do
+not exist or do not return useful results, tar emulates the calls at
+some cost in efficiency and reliability.
+
+** Symbolic link attributes
+
+When extracting symbolic links, tar now restores attributes such as
+last-modified time and link permissions, if the operating system
+supports this.  For example, recent versions of the Linux kernel
+support setting times on symlinks, and some BSD kernels also support
+symlink permissions.
+
+** --dereference consistency
+
+The --dereference (-h) option now applies to files that are copied
+into or out of archives, independently of other options.  For example,
+if F is a symbolic link and archive.tar contains a regular-file member
+also named F, "tar --overwrite -x -f archive.tar F" now overwrites F
+itself, rather than the file that F points to.  (To overwrite the file
+that F points to, add the --dereference (-h) option.)  Formerly,
+--dereference was intended to apply only when using the -c option, but
+the implementation was not consistent.
+
+Also, the --dereference option no longer affects accesses to other
+files, such as archives and time stamp files.  Symbolic links to these
+files are always followed.  Previously, the links were usually but not
+always followed.
 
 ** Spurious error diagnostics on broken pipe.