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- panic explicitly if the parent directory has been revoked.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.
