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authorJim Meyering <jim@meyering.net>2005-06-17 13:12:17 +0000
committerJim Meyering <jim@meyering.net>2005-06-17 13:12:17 +0000
commite89b22a2e10e931ad0e7c22063488b05ddc12010 (patch)
tree68fd5184d1dc00080122288b43c04dc3a9131eb2 /doc
parentd31922717094fe79477f2d55552317db06f2008c (diff)
downloadcoreutils-e89b22a2e10e931ad0e7c22063488b05ddc12010.tar.xz
(shred invocation): Clarify that shred
works on ext3 as long as it's not in data=journal mode. Patch from Mark Melahn.
Diffstat (limited to 'doc')
-rw-r--r--doc/coreutils.texi13
1 files changed, 11 insertions, 2 deletions
diff --git a/doc/coreutils.texi b/doc/coreutils.texi
index c2e39afd2..b85d2b3eb 100644
--- a/doc/coreutils.texi
+++ b/doc/coreutils.texi
@@ -7349,8 +7349,8 @@ assumption. Exceptions include:
@item
Log-structured or journaled file systems, such as those supplied with
-AIX and Solaris, and JFS, ReiserFS, XFS, Ext3, BFS, NTFS etc.@: when
-they are configured to journal @emph{data}.
+AIX and Solaris, and JFS, ReiserFS, XFS, Ext3 (in @code{data=journal} mode),
+BFS, NTFS, etc.@: when they are configured to journal @emph{data}.
@item
File systems that write redundant data and carry on even if some writes
@@ -7367,6 +7367,15 @@ clients.
Compressed file systems.
@end itemize
+In the particular case of ext3 filesystems, the above disclaimer applies (and
+@command{shred} is thus of limited effectiveness) only in @code{data=journal}
+mode, which journals file data in addition to just metadata. In both
+the @code{data=ordered} (default) and @code{data=writeback} modes,
+@command{shred} works as usual. Ext3 journaling modes can be changed
+by adding the @code{data=something} option to the mount options for a
+particular file system in the @file{/etc/fstab} file, as documented in
+the mount man page (man mount).
+
If you are not sure how your file system operates, then you should assume
that it does not overwrite data in place, which means that shred cannot
reliably operate on regular files in your file system.