When building the file system the existing code does an insertion into
a linked list. It attempts to speed this up by keeping a pointer to
where the last entry was inserted but it's still slow.

Now the nodes are just inserted into the list without searching
through for the correct place. This unsorted list is then sorted once
using mergesort after all the entries have been added to the list.
This speeds up the scanning of the flash file system considerably.

Signed-off-by: Mark Tomlinson <mark.tomlinson@alliedtelesis.co.nz>

If a sector has a CLEANMARKER at the beginning, it indicates that the
entire sector has been erased. Therefore, if this is found, we can skip the
entire block. This was not being done before this patch.

The code now does the same as the kernel does when encountering a
CLEANMARKER. It still checks that the next few words are FFFFFFFF, and if
so, the block is assumed to be empty, and so is skipped.

Signed-off-by: Mark Tomlinson <mark.tomlinson@alliedtelesis.co.nz>

The scan code is similar to the linux kernel, but the kernel defines a much
smaller size to scan through before deciding a sector is blank. Assuming
that what is in the kernel is OK, make these two match.

On its own, this change makes no difference to scanning of any sectors
which have a clean marker at the beginning, since the entire sector is not
blank.

Signed-off-by: Mark Tomlinson <mark.tomlinson@alliedtelesis.co.nz>

If the flash is slow, reading less from the flash into buffers makes
the process faster.

Signed-off-by: Mark Tomlinson <mark.tomlinson@alliedtelesis.co.nz>

jffs2_1pass_read_inode() would read the entire data for each node
in the filesystem, regardless of whether it was part of the file
to be loaded or not. By only reading the header data for an inode,
and then reading the data only when it is found to be part of the
file to be loaded, much copying of data is saved.

jffs2_1pass_list_inodes() read each inode for every file in the
directory into a buffer. By using NULL as a buffer pointer, NOR
flash simply returns a pointer, and therefore avoids a memory copy.

Signed-off-by: Mark Tomlinson <mark.tomlinson@alliedtelesis.co.nz>

If multiple versions of a file exist, only the most recent version
should be used. The scheme to write 0 for the inode in older versions
did not work, since this would have required writing to flash.

The only time this caused an issue was listing a directory, where older
versions of the file would still be seen. Since the directory entries
are sorted, just look at the next entry in the list, and if it's the same
move to that entry instead.

Signed-off-by: Mark Tomlinson <mark.tomlinson@alliedtelesis.co.nz>

Copying complete nodes from flash can be slow if the flash is slow
to read. By only reading the data needed, the sorting operation can
be made much faster.

The directory entry comparison function also had a two bugs. First, it
did not ensure the name was copied, so the name comparison may have
been faulty (although it would have worked with NOR flash).  Second,
setting the ino to zero to ignore the entry did not work, since this
was either writing to a temporary buffer, or (for NOR flash) directly
to flash. Either way, the change was not remembered.

Signed-off-by: Mark Tomlinson <mark.tomlinson@alliedtelesis.co.nz>

If a destination is not provided, jffs2_1pass_read_inode() only
returns the length of the file. In this case, avoid reading all
the data nodes, and return as soon as the length of the file is
known.

Signed-off-by: Mark Tomlinson <mark.tomlinson@alliedtelesis.co.nz>

This would be useful to start moving various config options.

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Acked-by: Simon Glass <sjg@chromium.org>
Tested-by: Simon Glass <sjg@chromium.org>

Clang interpretes an if condition like  "if ((a = b) == NULL)
as it tries to assign a value in a statement. Hence if you do
"if ((something)) it warns you that you might be confused.
Hence drop the double braces for plane if statements.

Signed-off-by: Jeroen Hofstee <jeroen@myspectrum.nl>