lockd: push lock_flocks down

lockd should use lock_flocks() instead of lock_kernel()
to lock against posix locks accessing the i_flock list.

This is a prerequisite to turning lock_flocks into a
spinlock.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: J. Bruce Fields <bfields@redhat.com>

2 files changed, 8 insertions, 12 deletions

diff --git a/fs/lockd/svc.c b/fs/lockd/svc.c
index b13aabc12298..abfff9d7979d 100644
--- a/fs/lockd/svc.c
+++ b/fs/lockd/svc.c
@@ -22,7 +22,6 @@
 #include <linux/in.h>
 #include <linux/uio.h>
 #include <linux/smp.h>
-#include <linux/smp_lock.h>
 #include <linux/mutex.h>
 #include <linux/kthread.h>
 #include <linux/freezer.h>
@@ -130,15 +129,6 @@ lockd(void *vrqstp)
 
         dprintk("NFS locking service started (ver " LOCKD_VERSION ").\n");
 
-        /*
-         * FIXME: it would be nice if lockd didn't spend its entire life
-         * running under the BKL. At the very least, it would be good to
-         * have someone clarify what it's intended to protect here. I've
-         * seen some handwavy posts about posix locking needing to be
-         * done under the BKL, but it's far from clear.
-         */
-        lock_kernel();
-
         if (!nlm_timeout)
                 nlm_timeout = LOCKD_DFLT_TIMEO;
         nlmsvc_timeout = nlm_timeout * HZ;
@@ -195,7 +185,6 @@ lockd(void *vrqstp)
         if (nlmsvc_ops)
                 nlmsvc_invalidate_all();
         nlm_shutdown_hosts();
-        unlock_kernel();
         return 0;
 }
 
diff --git a/fs/lockd/svcsubs.c b/fs/lockd/svcsubs.c
index d0ef94cfb3da..1ca0679c80bf 100644
--- a/fs/lockd/svcsubs.c
+++ b/fs/lockd/svcsubs.c
@@ -170,6 +170,7 @@ nlm_traverse_locks(struct nlm_host *host, struct nlm_file *file,
 
 again:
         file->f_locks = 0;
+        lock_flocks(); /* protects i_flock list */
         for (fl = inode->i_flock; fl; fl = fl->fl_next) {
                 if (fl->fl_lmops != &nlmsvc_lock_operations)
                         continue;
@@ -181,6 +182,7 @@ again:
                 if (match(lockhost, host)) {
                         struct file_lock lock = *fl;
 
+                        unlock_flocks();
                         lock.fl_type  = F_UNLCK;
                         lock.fl_start = 0;
                         lock.fl_end   = OFFSET_MAX;
@@ -192,6 +194,7 @@ again:
                         goto again;
                 }
         }
+        unlock_flocks();
 
         return 0;
 }
@@ -226,10 +229,14 @@ nlm_file_inuse(struct nlm_file *file)
         if (file->f_count || !list_empty(&file->f_blocks) || file->f_shares)
                 return 1;
 
+        lock_flocks();
         for (fl = inode->i_flock; fl; fl = fl->fl_next) {
-                if (fl->fl_lmops == &nlmsvc_lock_operations)
+                if (fl->fl_lmops == &nlmsvc_lock_operations) {
+                        unlock_flocks();
                         return 1;
+                }
         }
+        unlock_flocks();
         file->f_locks = 0;
         return 0;
 }