On Mon, 30 Jun 2008 13:10:19 -0400
"J. Bruce Fields" <bfields@xxxxxxxxxxxx> wrote:
> On Mon, Jun 30, 2008 at 08:35:36AM -0400, Jeff Layton wrote:
> > The idea looks reasonable, but the patch above doesn't apply to Bruce's
> > for-2.6.27 tree. The nfsd() function has changed a bit. Actually, I
> > think we can make this even simpler. kthreads start with all signals
> > ignored and the new patch enables all of the ones in SHUTDOWN_SIGS. So
> > I don't think we need any signal masking at all.
> >
> > How about this patch? It should apply on top of the patchset already
> > in Bruce's tree.
>
> Looks reasonable to me; applied for 2.6.27 barring any test failures or
> objections.
>
> --b.
>
Actually, here's an even simpler version. How about we just get rid of
the loop and just have a series of allow_signal() calls. We can get
rid of a local variable that way and since we're only referencing
SHUTDOWN_SIGS once, I don't see any reason to keep it around.
-------[snip]-----------
knfsd: treat all shutdown signals as equivalent
knfsd currently uses 2 signal masks when processing requests. A "loose"
mask (SHUTDOWN_SIGS) that it uses when receiving network requests, and
then a more "strict" mask (ALLOWED_SIGS, which is just SIGKILL) that it
allows when doing the actual operation on the local storage.
This is apparently unnecessarily complicated. The underlying filesystem
should be able to sanely handle a signal in the middle of an operation.
This patch removes the signal mask handling from knfsd altogether. When
knfsd is started as a kthread, all signals are ignored. It then allows
all of the signals in SHUTDOWN_SIGS. There's no need to set the mask
as well.
Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxx>
---
fs/nfsd/nfssvc.c | 30 +++++-------------------------
1 files changed, 5 insertions(+), 25 deletions(-)
diff --git a/fs/nfsd/nfssvc.c b/fs/nfsd/nfssvc.c
index 96fdbca..80292ff 100644
--- a/fs/nfsd/nfssvc.c
+++ b/fs/nfsd/nfssvc.c
@@ -37,15 +37,6 @@
#define NFSDDBG_FACILITY NFSDDBG_SVC
-/* these signals will be delivered to an nfsd thread
- * when handling a request
- */
-#define ALLOWED_SIGS (sigmask(SIGKILL))
-/* these signals will be delivered to an nfsd thread
- * when not handling a request. i.e. when waiting
- */
-#define SHUTDOWN_SIGS (sigmask(SIGKILL) | sigmask(SIGHUP) | sigmask(SIGINT) | sigmask(SIGQUIT))
-
extern struct svc_program nfsd_program;
static int nfsd(void *vrqstp);
struct timeval nfssvc_boot;
@@ -414,9 +405,7 @@ nfsd(void *vrqstp)
{
struct svc_rqst *rqstp = (struct svc_rqst *) vrqstp;
struct fs_struct *fsp;
- sigset_t shutdown_mask, allowed_mask;
int err, preverr = 0;
- unsigned int signo;
/* Lock module and set up kernel thread */
mutex_lock(&nfsd_mutex);
@@ -433,17 +422,14 @@ nfsd(void *vrqstp)
current->fs = fsp;
current->fs->umask = 0;
- siginitsetinv(&shutdown_mask, SHUTDOWN_SIGS);
- siginitsetinv(&allowed_mask, ALLOWED_SIGS);
-
/*
* thread is spawned with all signals set to SIG_IGN, re-enable
- * the ones that matter
+ * the ones that will bring down the thread
*/
- for (signo = 1; signo <= _NSIG; signo++) {
- if (!sigismember(&shutdown_mask, signo))
- allow_signal(signo);
- }
+ allow_signal(SIGKILL);
+ allow_signal(SIGHUP);
+ allow_signal(SIGINT);
+ allow_signal(SIGQUIT);
nfsdstats.th_cnt++;
mutex_unlock(&nfsd_mutex);
@@ -460,9 +446,6 @@ nfsd(void *vrqstp)
* The main request loop
*/
for (;;) {
- /* Block all but the shutdown signals */
- sigprocmask(SIG_SETMASK, &shutdown_mask, NULL);
-
/*
* Find a socket with data available and call its
* recvfrom routine.
@@ -487,9 +470,6 @@ nfsd(void *vrqstp)
/* Lock the export hash tables for reading. */
exp_readlock();
- /* Process request with signals blocked. */
- sigprocmask(SIG_SETMASK, &allowed_mask, NULL);
-
svc_process(rqstp);
/* Unlock export hash tables */
--
1.5.5.1
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