The next commit will make mode_t 32-bits, ino_t 64-bits, nlink_t
32-bits, and off_t 64-bits. However, in the protocol there is no
room for that.
When analyzing the usage of these data types we can see that of
mode_t we currently use 15 bits and that future flags (if copied
from NetBSD) are only of importance to VFS and not to the actual
file system on disk. Therefore we can get away with keeping the
protocol version of mode_t (pmode_t) 16 bits.
At this point it is unlikely that MINIX will support file systems
that can hold more than 2^32 files. Keeping the protocol version of
ino_t (pino_t) 32-bits and exposing it as 64-bits to the rest of the
system is fine.
uid_t and gid_t are already 32-bits, but in behind the scenes they're
16-bits. This is sufficient since we don't support uid/gids larger
than 2^16-1.
off_t will become 64-bits, but the protocol had room reserved
for that since it was revised years ago.
So to make the difference clear between what the protocol supports
and what is exposed to the system, we define protocol version of
these data types.
Change-Id: Ifb883aafb222142e69d6dcc3049a47170b78b3ee
REQ_PEEK behaves just like REQ_READ except that it does not copy
data anywhere, just obtains the blocks from the FS into the cache.
To be used by the future mmap implementation.
Change-Id: I1b56de304f0a7152b69a72c8962d04258adb44f9
. 'anonymous' cache blocks (retrieved with NO_DEV as dev
parameter) were used to implement read()s from holes in
inodes that should return zeroes
. this is an awkward special case in the cache code though
and there's a more direct way to implement the same functionality:
instead of copying from a new, anonymous, zero block, to
the user target buffer, simply sys_safememset the user target
buffer directly. as this was the only use of this feature,
this is all that's needed to simplify the cache code a little.
Add primary cache management feature to libminixfs as mfs and ext2
currently do separately, remove cache code from mfs and ext2, and make
them use the libminixfs interface. This makes all fields of the buf
struct private to libminixfs and FS clients aren't supposed to access
them at all. Only the opaque 'void *data' field (the FS block contents,
used to be called bp) is to be accessed by the FS client.
The main purpose is to implement the interface to the 2ndary vm cache
just once, get rid of some code duplication, and add a little
abstraction to reduce the code inertia of the whole caching business.
Some minor sanity checking and prohibition done by mfs in this code
as removed from the generic primary cache code as a result:
- checking all inodes are not in use when allocating/resizing
the cache
- checking readonly filesystems aren't written to
- checking the superblock isn't written to on mounted filesystems
The minixfslib code relies on fs_blockstats() in the client filesystem to
return some FS usage information.
.enable all compile time warnings and make them errors
.refactor functions with unused parameters
.fix null pointer dereference before checking for null
.proper variable initialization
.use safe string copy functions
.fix massive memory corruption bug in fs_getdents
. all invocations were S or D, so can safely be dropped
to prepare for the segmentless world
. still assign D to the SCP_SEG field in the message
to make previous kernels usable
