Not all mtd drivers define block_isbad().  Let's assume no bad blocks
instead of refusing to mount.
Signed-off-by: NJoern Engel <joern@logfs.org>

Fixes generated by 'codespell' and manually reviewed.
Signed-off-by: NLucas De Marchi <lucas.demarchi@profusion.mobi>

a) switch ->put_device() to logfs_super *
b) actually call it on early failures in logfs_get_sb_device()
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

take logfs_get_sb_device() calls to logfs_get_sb() itself
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

take setting s_bdev/s_mtd/s_devops to callers of logfs_get_sb_device(),
don't bother passing them separately
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

move allocation of logfs_super to logfs_get_sb, pass it to
logfs_get_sb_...().
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

The write buffer may not have been written and may no longer be written
due to an interrupted write in the affected page.
Signed-off-by: NJoern Engel <joern@logfs.org>

The get_mtd_device() function returns error pointers on failure and if we
don't handle it, it leads to a crash.
Signed-off-by: NDan Carpenter <error27@gmail.com>
Signed-off-by: NJoern Engel <joern@logfs.org>

Erases for block devices were always just emulated by writing 0xff.
Some time back the write was removed and only the page cache was
changed to 0xff.  Superficialy a good idea with two problems:
1. Touching the page cache isn't necessary either.
2. However, writing out 0xff _is_ necessary for the journal.  As the
   journal is scanned linearly, an old non-overwritten commit entry
   can be used on next mount and cause havoc.

This should fix both aspects.

This is a new flash file system. See
Documentation/filesystems/logfs.txt
Signed-off-by: NJoern Engel <joern@logfs.org>