avoid having to allocate space in the 'stackgap'
- which is very LWP unfriendly.
The additional code for non-emulation namei() is trivial, the reduction for
the emulations is massive.
The vnode for a processes emulation root is saved in the cwdi structure
during process exec.
If the emulation root the TRYEMULROOT flag are set, namei() will do an initial
search for absolute pathnames in the emulation root, if that fails it will
retry from the normal root.
".." at the emulation root will always go to the real root, even in the middle
of paths and when expanding symlinks.
Absolute symlinks found using absolute paths in the emulation root will be
relative to the emulation root (so /usr/lib/xxx.so -> /lib/xxx.so links
inside the emulation root don't need changing).
If the root of the emulation would be returned (for an emulation lookup), then
the real root is returned instead (matching the behaviour of emul_lookup,
but being a cheap comparison here) so that programs that scan "../.."
looking for the root dircetory don't loop forever.
The target for symbolic links is no longer mangled (it used to get the
CHECK_ALT_xxx() treatment, so could get /emul/xxx prepended).
CHECK_ALT_xxx() are no more. Most of the change is deleting them, and adding
TRYEMULROOT to the flags to NDINIT().
A lot of the emulation system call stubs could now be deleted.
- don't use SAVESTART in calls to relookup() from unionfs,
just vref() the desired vnode when we need to.
- fix locking and refcounting in the unionfs EEXIST error cases.
- release any vnode locks before calling VFS_ROOT(), vfs_busy() is enough.
this allows us to simplify union_root() and fix PR 3006.
- union_lock() doesn't handle shared lock requests correctly,
so convert them to exclusive instead. fixes PR 34775.
- in relookup(), avoid reusing "dp" for different purposes,
the error handling wasn't right. (actually just get rid of dp.)
also, change relookup() to ignore LOCKLEAF and always return the
vnode locked since the callers already expect this.
returned from nfs_namei() is not locked in this case. fixes PR 35542.
also, apply the same fix here as was made in rename_files() to handle
the case when dvp and vp are the same.
by Slava Semushin <slava.semushin@gmail.com>.
To verify that no nasty side effects of duplicate includes (or their
removal) have an effect here, I've compiled an i386/ALL kernel with
and without the patch, and the only difference in the resulting .o
files was in shifted line numbers in some assert() calls.
The comparison of the .o files was based on the output of "objdump -D".
Thanks to martin@ for the input on testing.
The suspension helpers are now put into file system specific operations.
This means every file system not supporting these helpers cannot be suspended
and therefore snapshots are no longer possible.
Implemented for file systems of type ffs.
The new API is enabled on a kernel option NEWVNGATE. This option is
not enabled by default in any kernel config.
Presented and discussed on tech-kern with much input from
Bill Studenmund <wrstuden@netbsd.org> and YAMAMOTO Takashi <yamt@netbsd.org>.
Welcome to 4.99.9 (new vfs op vfs_suspendctl).
- LOCKPARENT is no longer relevant for lookup(), relookup() or VOP_LOOKUP().
these now always return the parent vnode locked. namei() works as before.
lookup() and various other paths no longer acquire vnode locks in the
wrong order via vrele(). fixes PR 32535.
as a nice side effect, path lookup is also up to 25% faster.
- the above allows us to get rid of PDIRUNLOCK.
- also get rid of WANTPARENT (just use LOCKPARENT and unlock it).
- remove an assumption in layer_node_find() that all file systems implement
a recursive VOP_LOCK() (unionfs doesn't).
- require that all file systems supply vfs_vptofh and vfs_fhtovp routines.
fill in eopnotsupp() for file systems that don't support being exported
and remove the checks for NULL. (layerfs calls these without checking.)
- in union_lookup1(), don't change refcounts in the ISDOTDOT case, just
adjust which vnode is locked. fixes PR 33374.
- apply fixes for ufs_rename() from ufs_vnops.c rev. 1.61 to ext2fs_rename().
loops where vnodes can get removed or added during the loops. This could
lead to panic's on unmount since nodes are skipped or otherwise
TAILQ_NEXT(0xdeadbeef, ...) was dereferenced.
vnodes were synced and processed backwards. This meant that the last
accessed node was processed first and the earlierst last.
An extra benefit is the removal of the ugly hack from the Berkly days on
LFS.
In the proces, i've also replaced the various variations hand written loops
by the TAILQ_FOREACH() macro's.
yamt