It does not help modern compilers, and some may take some hit from it.
(I also found several functions that listed *every* of its 10 local vars with
"register" -- just how many free registers do people think machines have?)
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
utilities which use bits of fsck_ffs - namely quotacheck and fsdb.
In depth, utilities.c contains blockcheck() which is needed by both,
but also a slew of routines which require bits of the FFS code to be
compiled in. This breaks the fs-specific and non-fs-specific code
up into two files (well, blockcheck() is the only routine in utilities.c,
that'll change later) which makes building fsck_ffs, quotacheck and
fsdb work yet again.
(You won't find commits to fsdb and quotacheck here before I haven't
committed the post-fsck-wrappers version of them yet.)
