to do two things:
1) properly set "recycle?" in inactive
2) easily check if we are renaming a removed vnode. without the
check, it was possible to enter a dirent in the file system for
a removed (and hence scheduled to be vcleaned) vnode. this would
lead to the succesful vget() of a clean vnode. the use of the
cleaned vnode was, however, less succesful, except for purposes
of crashing.
the value before the call (yea, changing relookup would probably
be smart, but other file systems already initialize vpp, so I'm
letting someone else experiment with tylenol od).
system drivers where it was missing from and fixes one buggy
implementation. The arguably weird semantics of the check are
maintained (v_size vs. va_bytes, overwrite).
unlike event it did fail, the kernel would double lutz to doom
(in failure devvp now remains unmountable until reboot. fans
of complicated & untested error branches may attempt to gunk this
up. i'm not one of them).
* cosmetic surgery: cut extra ;
msdosfs and cd9660 are the only filesystems that verify the filesystem
type in the label. This is the wrong place, sanity checks should only
rely on the inner structure of the filesystem (like signatures or
magic numbers).
msdosfs also used the device type information from the label to
deduce a filesystem parameter heuristically for the gemdos variant.
If there is no information inside the filesystem data itself, this
should be an explicit mount option.
operations. This prevents kernel memory leaks (one of which happened
every time the file system was unmounted via PUFFSOP_UNMOUNT ...
and incidentally would've been trivially caught with the old
malloc(9) interface. I wonder if the message is to use a ton of
pools instead of regression-attractive kmem interface).
reference the puffs_node before sending the request to the file
server. This diminishes the window where the inode can be reclaimed
and be invalidated before it is accessed (but does not completely
eliminate the race, as that is a caller problem which we cannot
fix here).
years ago when the kernel was modified to not alter ABI based on
DIAGNOSTIC, and now just call the respective function interfaces
(in lowercase). Plenty of mix'n match upper/lowercase has creeped
into the tree since then. Nuke the macros and convert all callsites
to lowercase.
no functional change
to initiate self destruct, i.e. unmount(MNT_FORCE). This, however,
is a semi-controlled self-destruct, since all caches are flushed
before the (possibly) violent unmount takes place.
context. This fixes a long-standing but seldomly seen deadlock,
where the kernel was holding pages busy (due to e.g. readahead
request) while waiting for the server to respond, and the server
made a callback into the kernel asking to invalidate those pages.
... or, well, theoretically fixes, since I didn't have any reliable
way of repeating the deadlock and I think I saw it only twice.
hannken