Therefore, storing the value in the superblock and reading it out
again is silly and offers the opportunity for it to become corrupted.
So, don't do that (most of the code already didn't) and use the
existing constant instead. Initialize new 32-bit superblocks with
the value for the sake of old userland programs, but don't keep the
value in the 64-bit superblock at all.
(approved by Margo Seltzer)
This prevents regressions in the ulfs code when switching to the new
accessors. Note that while adding byteswapping to the other accessors
is straightforward, I haven't done it yet; and that also is not enough
to make LFS_EI work, because there are places lying around that bypass
the accessors for one reason and another and all of them need to be
updated. That is going to have to wait for a later day as LFS_EI is
not on the critical path right now.
(This part changes the native lfs code; the ufs-derived code already
has 64 vs. 32 logic, but as aspects of it are unsafe, and don't
entirely interoperate cleanly with the lfs 64/32 stuff, pass 2 will be
rehashing that.)
Also make note of a cleaner limitation: it seems that when it goes to
coalesce discontiguous files, it mallocs an array with one BLOCK_INFO
for every block in the file. Therefore, with 64-bit LFS, on a 32-bit
platform it will be possible to have files large enough to overflow
the cleaner's address space. Currently these will be skipped and cause
warnings via syslog.
At some point someone should rewrite the logic to coalesce files to
use chunks of some reasonable size, as discontinuity between such
chunks is immaterial and mallocing this much space is silly and
fragile. Also, the kernel only accepts up to 65536 blocks at a time
for bmapv and markv, so processing more than this at once probably
isn't useful and may not even work currently. I don't want to change
this around just now as it's not entirely trivial.
Add pieces of support for using both superblock types where
convenient, and specifically to the superblock accessors, but don't
actually enable it anywhere.
First substantive step on PR 50000.
This contains all the accessor functions and macros out of lfs.h.
Add an include of lfs_accessors.h after all uses of lfs.h... except
for code that wants to define its own struct lfs-alike that the
accessors are supposed to play along with. For these, set STRUCT_LFS
and include lfs_accessors.h after the necessary structure has been
defined, so that lfs_accessors.h can emit functions in terms of it.
(This changes the rest of the code over; all the accessors were
already added.)
The difference between this commit and the previous one is arbitrary,
but the previous one passed the regression tests on its own so I'm
keeping it separate to help with any bisections that might be needed
in the future.
superblock. This will allow switching between 32/64 bit forms on the
fly; it will also allow handling LFS_EI reasonably tidily. (That
currently doesn't work on the superblock.)
It also gets rid of cpp abuse in the form of fake structure member
macros.
Also, instead of doing sleep/wakeup on &lfs_avail and &lfs_nextseg
inside the on-disk superblock, add extra elements to the in-memory
struct lfs for this. (XXX: these should be changed to condvars, but
not right now)
XXX: this migrates a structure needed by the lfs code in libsa (struct
salfs) into lfs.h, where it doesn't belong, but for the time being
this is necessary in order to allow the accessors (and the various
lfs macros and other goop that relies on them) to compile.
This fixes the most of lockups i observed with Open vSwitch
on NetBSD/amd64. ("most of" because it still occasionally
locks up because of other problems. see PR/49816)
dholland