[I first added this functionality, and thought to check prior art. Seeing
OpenBSD had already done this, I changed my addition to reduce the diffs
between the two and went with their option letter.]
Obtained from: OpenBSD
in-core pointers to summary information. An array in this region
(fs_csp) could overflow on filesystems with a very large number of
cylinder groups (~16000 on i386 with 8k blocks). When this happens,
other fields in the superblock get corrupted, and fsck refuses to
check the filesystem.
Solve this problem by replacing the fs_csp array in 'struct fs'
with a single pointer, and add padding to keep the length of the
128-byte region fixed. Update the kernel and userland utilities
to use just this single pointer.
With this change, the kernel no longer makes use of the superblock
fields 'fs_csshift' and 'fs_csmask'. Add a comment to newfs/mkfs.c
to indicate that these fields must be calculated for compatibility
with older kernels.
Reviewed by: mckusick
touch ups. The cache needs to be flushed against block
reads, and a final flush at process termination to force the
backup superblocks to disk.
I believe this will allow 'make release' to complete.
Submitted by: Tor.Egge@fast.no
for large scsi disks with WCE = 0. This yields around a 7 times speedup
on elapsed newfs time on test disks here. 64k clusters seems to be the
sweet spot for scsi disks using our present drivers.
the mount is completely active, causing the next few commands attempting
to manipulate data on the mount to fail. mount_mfs's parent now tries
to wait for the mount point st_dev to change before returning, indicating
that the mount has gone active.
for filesystems with almost the maximum number of sectors. The maxiumum
is 2^31, but overflow is common for that size, and overflow normally
occurred here at size (2^31 - 4096).
size was rounded up to a multiple of the fragment size, but this
gave invalid file systems when the fragment size was > SBSIZE (fsck
aborts early on them). Now a fragment size of 32768 seems to work
(too-simple tests with fsck and iozone worked).
higher up in memory (0x0800000 upwards) rather than near zero (0x1000
for our qmagic a.out format). The method that mount_mfs uses to allocate
the memory within data size rlimits for the ram disk is entirely too much
of a kludge for my liking. I mean, if it's run as root, surely it makes
sense to just raise the resource limits to infinity or something, and if
it's a non-root user mount (do these work? with mfs?) it could just fail
if it's outside limits.
better hack in ffs_vfsops.c. The hack here restricted the maximum file
size to 2^39 bytes (512GB). fs_bsize * 2^31 - 1 (16TB for the default
blocksize of 8K) would have been better. There is no good way to remove
this limit on old BSD4.4 file systems.
it's internal malloc() implementation to try and avoid overstepping it's
resource limits (yuk!). Remain using libc's malloc(), but check the
resource limits right before trying to malloc the ramdisk space and leave
some spare memory for libc. In Andrey's words, the internal malloc
was "true evil".. Among it's sins is it's ability to allocate less memory
than asked for and still return success. stdio would just love that. :-)
Reviewed by: ache
automatically have random generation numbers. The kenel way of handling those
also changed. Further it is advised to run fsirand on all your nfs exported
filesystems. the code is mostly copied from OpenBSD, with the randomization
chanegd to use /dev/urandom
Reviewed by: Garrett
Obtained from: OpenBSD
- Use MAP_FAILED instead of the constant -1 to indicate
failure (required by POSIX).
- Removed flag arguments of '0' (required by POSIX).
- Fixed code which expected an error return of 0.
- Fixed code which thought any address with the high bit set
was an error.
- Check for failure where no checks were present.
Discussed with: bde
the sd & od drivers. There is also slight changes to fdisk & newfs
in order to comply with different sectorsizes.
Currently sectors of size 512, 1024 & 2048 are supported, the only
restriction beeing in fdisk, which hunts for the sectorsize of
the device.
This is based on patches to od.c and the other system files by
John Gumb & Barry Scott, minor changes and the sd.c patches by
me.
There also exist some patches for the msdos filesys code, but I
havn't been able to test those (yet).
John Gumb (john@talisker.demon.co.uk)
Barry Scott (barry@scottb.demon.co.uk)
being output if <= 1 rpos; there is a bug in the kernel which doesn't
quite get along with this. Changed default #rpos to 1, and fixed up
manual page. Converted nrpos to 1 if user specifies 0.
the use of the rotational position table.
2) Allow specification of 0 rotational positions (disables function).
3) Make rotdelay=0 and nrpos=0 by default.
The purpose of the above is to optimize for modern SCSI (and IDE) drives
that do read-ahead/write-behind.
