nfsd: 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@redhat.com>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>

diff --git a/fs/nfsd/nfssvc.c b/fs/nfsd/nfssvc.c
index 96fdbca..80292ff 100644 (file)
--- 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 */