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>

1 files changed, 5 insertions, 25 deletions

diff --git a/fs/nfsd/nfssvc.c b/fs/nfsd/nfssvc.c
index 96fdbcab8d95..80292ff5e924 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 */