mke2fs: fix man page discussion of usage type defaults

The man page description of the file system size thresholds used by
mke2fs to select a usage type when not otherwise specified by the -T
switch does not match the code.

Signed-off-by: Eric Whitney <enwlinux@gmail.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
util: allow subst to build on systems that do not have utimes()

Make subst more portable so it can deal with such oler systems that do
not have utimes().  Note that it is important that subst build
correctly without an autoconf-generated config.h (since that is what
happens on a cross-compile), as well as using whatever features are
available as determined by autoconf when doing a native build.  We
currently assume the presence of utime(), but not utimes() or
futimes().

Signed-off-by: Theodore Ts'o <tytso@mit.edu>
libext2fs: fix endian handling of ext3_extent_header

This turned up when trying to resize a filesystem containing
a file with many extents on PPC64.

Fix all locations where ext3_extent_header members aren't
handled in an endian-safe manner.

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
libext2fs: directory iteration mustn't walk off the buffer end

When we're iterating a directory, the loop control code reads the
length of the next directory record, failing to account for the fact
that there must be at least 8 bytes (the minimum size of a directory
entry) left in the buffer to read the next directory record.  Fix the
loop conditional so that we don't read off the end of the buffer.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reported-by: Sami Liedes <sami.liedes@iki.fi>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
libext2fs: don't memcpy identical pointers when writing a cache block

Sami Liedes found a scenario where we could memcpy incorrectly:

If a block read fails during an e2fsck run, the UNIX IO manager will
call the io->read_error routine with a pointer to the internal block
cache.  The e2fsck read error handler immediately tries to write the
buffer back out to disk(!), at which point the block write code will
try to copy the buffer contents back into the block cache.  Normally
this is fine, but not when the write buffer is the cache itself!

So, plumb in a trivial check for this condition.  A more thorough
solution would pass a duplicated buffer to the IO error handlers, but
I don't know if that happens frequently enough to be worth the extra
point of failure.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reported-by: Sami Liedes <sami.liedes@iki.fi>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>