create_inode: clean up return mess in do_write_internal

do_write_internal returns errno when ext2 library calls fail; since
errno only reflects the outcome of the last C library call, this will
result in confused callers.  Eliminate the naked return since
this results in an undefined return value.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
create_inode: minor cleanups

Fix a couple of small style issues in the create_inode files.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Andreas Dilger <adilger@dilger.ca>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
create_inode: whitespace fixes

Fix a ton of whitespace issues.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
create_inode: move debugfs internal state back to debugfs

Since create_inode.c is shared between debugfs and mke2fs, don't
spread debugfs internal state into mke2fs.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
create_inode: handle hard link inum mappings per populate_fs invocation

When calling populate_fs, the map for hardlink detection is not
cleaned up between populate_fs invocations, which could lead to
unexpected results if anyone calls populate_fs twice in the same
client program).  This doesn't happen right now, but we might as well
clean it up.

The detctor fails if the external directory crosses mountpoints,
so fix that too.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
create_inode: fix gcc -Wall complaints

We had several functions that were not returning zero on success.  Fix
this.

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
debugfs, libext2fs: minor fixups to xattr support

Add magic number checking to the extended attribute editing handle;
move inline data to the head of the attribute list when writing so
that inline data ends up in the inode area; and always zero the
attribute space before writing to ensure that we can delete the last
xattr.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
debugfs: create commands to edit extended attributes

Enhance debugfs to be able to display and modify extended attributes, and
create some simple tests for the extended attribute editing functions.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>