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.
. No functional change
. Only serves to get hooks to do checks in
. e.g. should things be marked dirty when we are
mounted readonly
Signed-off-by: Ben Gras <ben@minix3.org>
The "bdev" library provides basic primitives for file systems to talk
to block device drivers, hiding the details of the underlying protocol
and interaction model.
This version of libbdev is rather basic. It is planned to support the
following features in the long run:
- asynchronous requests and replies;
- recovery support for underlying block drivers;
- retrying of failed I/O requests.
The commit also changes our block-based file systems (mfs, ext2, isofs)
to make use of libbdev.
. move mfs-specific struct, constants to mfs/, so
mfs-specific, on-disk format structs and consts are
fully isolated from generic structs and functions
. removes de and readfs utils
- Remove unused includes.
- Add include guards to headers.
- Use unsigned variables in case they're never going to hold a negative
value. This causes GCC's complaints to disappear and should make flexelint
a lot happier, too.
- Make functions private when they're used only within a module.
- Remove unused variables.
- Add casts where appropriate.
VFS CHANGES:
- dmap table no longer statically initialized in VFS
- Dropped FSSIGNON svrctl call no longer used by INET
INET CHANGES:
- INET announces its presence to VFS just like any other driver
RS CHANGES:
- The boot image dev table contains all the data to initialize VFS' dmap table
- RS interface supports asynchronous up and update operations now
- RS interface extended to support driver style and flags
- Revise VFS-FS protocol and update VFS/MFS/ISOFS accordingly.
- Clean up MFS by removing old, dead code (backwards compatibility is broken by
the new VFS-FS protocol, anyway) and rewrite other parts. Also, make sure all
functions have proper banners and prototypes.
- VFS should always provide a (syntactically) valid path to the FS; no need for
the FS to do sanity checks when leaving/entering mount points.
- Fix several bugs in MFS:
- Several path lookup bugs in MFS.
- A link can be too big for the path buffer.
- A mountpoint can become inaccessible when the creation of a new inode
fails, because the inode already exists and is a mountpoint.
- Introduce support for supplemental groups.
- Add test 46 to test supplemental group functionality (and removed obsolete
suppl. tests from test 2).
- Clean up VFS (not everything is done yet).
- ISOFS now opens device read-only. This makes the -r flag in the mount command
unnecessary (but will still report to be mounted read-write).
- Introduce PipeFS. PipeFS is a new FS that handles all anonymous and
named pipes. However, named pipes still reside on the (M)FS, as they are part
of the file system on disk. To make this work VFS now has a concept of
'mapped' inodes, which causes read, write, truncate and stat requests to be
redirected to the mapped FS, and all other requests to the original FS.
. changed umount() and mount() to call 'service', so that it can include
a custom label, so that umount() works again (RS slot gets freed now).
merged umount() and mount() into one file to encode keep this label
knowledge in one file.
. removed obsolete RS_PID field and RS_RESCUE rescue command
. added label to RS_START struct
. vfs no longer does kill of fs process on unmount (which was failing
due to RS_PID request not working)
. don't assume that if error wasn't one of three errors, that no error
occured in vfs/request.c
mfs changes:
. added checks to copy statements to truncate copies at buffer sizes
(left in debug code for now)
. added checks for null-terminatedness, if less than NAME_MAX was copied
. added checks for copy function success
is changes:
. dump rs label
drivers.conf changes:
. added acl for mfs so that mfs can be started with 'service start',
so that a custom label can be provided
print debug message if copy is truncated
. increased buffer in lookup() to be PATH_MAX instead of NAME_MAX
. sanity check in fetch_name() in vfs to see if name fits, and
is null-terminated
. first check i < NAME_MAX, then string[i] in search_dir, as we're
not supposed to look at string[NAME_MAX]
