This patch changes the prefetch API so that file systems must now
provide a set of block numbers, rather than a set of buffers. The
result is a leaner and more well-defined API; linear computation of
the range of blocks to prefetch; duplicates no longer interfering
with the prefetch process; guaranteed inclusion of the block needed
next into the prefetch range; and, limits and policy decisions better
established by libminixfs now actually being moved into libminixfs.
Change-Id: I7e44daf2d2d164bc5e2f1473ad717f3ff0f0a77f
- The lmfs_get_block*(3) API calls may now return an error. The idea
is to encourage a next generation of file system services to do a
better job at dealing with block read errors than the MFS-derived
implementations do. These existing file systems have been changed
to panic immediately upon getting a block read error, in order to
let unchecked errors cause corruption. Note that libbdev already
retries failing I/O operations a few times first.
- The libminixfs block device I/O module (bio.c) now deals properly
with end-of-file conditions on block devices. Since a device or
partition size may not be a multiple of the root file system's block
size, support for partial block retrival has been added, with a new
internal lmfs_get_partial_block(3) call. A new test program,
test85, tests the new handling of EOF conditions when reading,
writing, and memory-mapping a block device.
Change-Id: I05e35b6b8851488328a2679da635ebba0c6d08ce
This patch changes the libminixfs API and implementation such that the
library is at all times aware of how many total and used blocks there
are in the file system. This removes the last upcall of libminixfs
into file systems (fs_blockstats). In the process, make this part of
the libminixfs API a little prettier and more robust. Change file
systems accordingly. Since this change only adds to MFS being unable
to deal with zones and blocks having different sizes, fail to mount
such file systems immediately rather than triggering an assert later.
Change-Id: I078e589c7e1be1fa691cf391bf5dfddd1baf2c86
