We are going to re-work the MTD interface and change 'mtd->write()' to
'mtd_write()', 'mtd->read()' to 'mtd_read()' and so forth for all functions
in the 'struct mtd_info' structure.

However, logfs has its own 'mtd_read()', 'mtd_write()', etc functions
which collide with our changes. This patch renames these logfs functions
to 'logfs_mtd_read()', 'logfs_mtd_write()', etc.

Additionally, to make the 'fs/logfs/dev_mtd.c' file look consistent, rename
similarly all the other functions starting with 'mtd_'.

Cc: Jörn Engel <joern@logfs.org>
Signed-off-by: NArtem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: NDavid Woodhouse <David.Woodhouse@intel.com>

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>