My understanding is that the CLRSIG() is supposed to clear the signal
that was sent to the syncer process to prevent it from being delivered
to the syncer process in case unmounting fails, so that the syncer process
does not die while the filesystem is still mounted. The typical scenario
is, the syncher process is tsleep()ing in the kernel, and waking up when
it needs to do work. If someone sends a signal to it, eg. kill -TERM
the mfs process, then the kernel will try to unmount the mfs filesystem
before delivering the signal to the process. If that unmount fails, then
we should not really kill the process because that will hang the mount.
So we call CLRSIG() to stop the signal from being delivered.
So the first call to issignal() will return the signal number that was
sent to the syncer process (unless someone malicious was able to send
a lower numbered signal between the time tsleep() returned and we called
issignal()... something that is not really easy to do). But you are
right, we should not be calling it many times as a side effect of this
macro.
Rewrite CLRSIG() clear all the signals and call issignal() the correct
number of times.
- remove GOP_SIZE_READ/GOP_SIZE_WRITE flags.
they have not been used since the change.
- ufs_balloc_range: remove code which has been no-op since the change.
thanks Konrad Schroder for explaining the original intention of the code.
- ffs_gop_size: don't extend past eof, in the case of GOP_SIZE_MEM.
otherwise genfs_getpages end up to allocate pages past eof unnecessarily.
- use vmspace rather than proc or lwp where appropriate.
the latter is more natural to specify an address space.
(and less likely to be abused for random purposes.)
- fix a swdmover race.
- don't bother to take nfs_sndlock when doing nfsrv_rcv.
unlike client, we never reconnect.
- nfsrv_getstream: fix the case that m_split sleeps.
- free socket in nfsrv_slpderef rather than nfsrv_zapsock.
fix race with nfssvc_nfsd.
- while i'm here, remove NFSD_WAITING and NFSD_REQINPROG
as they are redundant.
- some comments and assertions.
- use LK_CANRECURSE instead of LK_RECURSEFAIL.
PR/32435 from Valeriy E. Ushakov.
- panic explicitly if the parent directory has been revoked.
add an XXX comment.
Solves a crash when mounting NFS shares. (The proc parameter used before
the conversion to lwp's was NULL too, so the addition of 'l->l_proc' in the
code was extra.)
shortcut to the process of the passed lwp paniced the kernel since lwp
could/can be passwd as NULL in VOP_WRITE().
This was happening when ktracing to NFS. The function ktrwrite() set the
uio_lwp to NULL and then calls VOP_WRITE() with this argument. nfs_write()
then accessed lwp *l->l_proc wich paniced.
Thanks to David Laight for his help on tracking it down.
nfs errors are chosen to be the same as errno, some of them are not and
it is better for portability to do the conversion anyway. Also a server
can return a bad error number that can cause the server to crash, because
it can have the high bits that are used internally set. This was the case
with amd. Finally nfs_request() should return a valid errno, because we
can return a bogus value to userland. Thanks to rpaulo for debugging this.
- Remove all NFS related stuff from file system specific code.
- Drop the vfs_checkexp hook and generalize it in the new nfs_check_export
function, thus removing redundancy from all file systems.
- Move all NFS export-related stuff from kern/vfs_subr.c to the new
file sys/nfs/nfs_export.c. The former was becoming large and its code
is always compiled, regardless of the build options. Using the latter,
the code is only compiled in when NFSSERVER is enabled. While doing this,
also make some functions in nfs_subs.c conditional to NFSSERVER.
- Add a new command in nfssvc(2), called NFSSVC_SETEXPORTSLIST, that takes a
path and a set of export entries. At the moment it can only clear the
exports list or append entries, one by one, but it is done in a way that
allows setting the whole set of entries atomically in the future (see the
comment in mountd_set_exports_list or in doc/TODO).
- Change mountd(8) to use the nfssvc(2) system call instead of mount(2) so
that it becomes file system agnostic. In fact, all this whole thing was
done to remove a 'XXX' block from this utility!
- Change the mount*, newfs and fsck* userland utilities to not deal with NFS
exports initialization; done internally by the kernel when initializing
the NFS support for each file system.
- Implement an interface for VFS (called VFS hooks) so that several kernel
subsystems can run arbitrary code upon receipt of specific VFS events.
At the moment, this only provides support for unmount and is used to
destroy NFS exports lists from the file systems being unmounted, though it
has room for extension.
Thanks go to yamt@, chs@, thorpej@, wrstuden@ and others for their comments
and advice in the development of this patch.
of curproc (where uio->uio_procp should be used?). Don't do this
for nfs_commit(), because yamt says it is possibly wrong.
2. nfs_doio() does not use struct proc; remove it and the code to compute it.
3. use copyin_proc() and copyout_proc() instead of copyin() and copyout().
4. check return of copyout_proc(). and mark return from copyin_proc() XXX
5. Eliminate check p == curproc assertion check from nfs_write;
nfs_read does not have it and we might be called in a different
process context anyway (PR 20138).
into the "vfsops" link set.
- Use VFS_ATTACH() where vfsops are declared for individual file systems.
- In vfsinit(), traverse the "vfsops" link set, rather than vfs_list_initial[].
this means we can no longer look at the vnode size to determine how many
pages to request in a fault, which is good since for NFS the size can change
out from under us on the server anyway. there's also a new flag UBC_UNMAP
for ubc_release(), so that the file system code can make the decision about
whether to cache mappings for files being used as executables.
blymn