Merge git://git.kernel.org/pub/scm/linux/kernel/git/steve/gfs2-2.6-nmw

* git://git.kernel.org/pub/scm/linux/kernel/git/steve/gfs2-2.6-nmw: (51 commits)
  [DLM] block dlm_recv in recovery transition
  [DLM] don't overwrite castparam if it's NULL
  [GFS2] Get superblock a different way
  [GFS2] Don't try to remove buffers that don't exist
  [GFS2] Alternate gfs2_iget to avoid looking up inodes being freed
  [GFS2] Data corruption fix
  [GFS2] Clean up journaled data writing
  [GFS2] GFS2: chmod hung - fix race in thread creation
  [DLM] Make dlm_sendd cond_resched more
  [GFS2] Move inode deletion out of blocking_cb
  [GFS2] flocks from same process trip kernel BUG at fs/gfs2/glock.c:1118!
  [GFS2] Clean up gfs2_trans_add_revoke()
  [GFS2] Use slab operations for all gfs2_bufdata allocations
  [GFS2] Replace revoke structure with bufdata structure
  [GFS2] Fix ordering of dirty/journal for ordered buffer unstuffing
  [GFS2] Clean up ordered write code
  [GFS2] Move pin/unpin into lops.c, clean up locking
  [GFS2] Don't mark jdata dirty in gfs2_unstuffer_page()
  [GFS2] Introduce gfs2_remove_from_ail
  [GFS2] Correct lock ordering in unlink
  ...

1 files changed, 190 insertions, 103 deletions

diff --git a/fs/gfs2/glock.c b/fs/gfs2/glock.c
index 3f0974e1afef..a37efe4aae6f 100644
--- a/fs/gfs2/glock.c
+++ b/fs/gfs2/glock.c
@@ -25,8 +25,10 @@
 #include <asm/uaccess.h>
 #include <linux/seq_file.h>
 #include <linux/debugfs.h>
-#include <linux/module.h>
-#include <linux/kallsyms.h>
+#include <linux/kthread.h>
+#include <linux/freezer.h>
+#include <linux/workqueue.h>
+#include <linux/jiffies.h>
 
 #include "gfs2.h"
 #include "incore.h"
@@ -48,7 +50,6 @@ struct glock_iter {
         int hash;                     /* hash bucket index         */
         struct gfs2_sbd *sdp;         /* incore superblock         */
         struct gfs2_glock *gl;        /* current glock struct      */
-        struct hlist_head *hb_list;   /* current hash bucket ptr   */
         struct seq_file *seq;         /* sequence file for debugfs */
         char string[512];             /* scratch space             */
 };
@@ -59,8 +60,13 @@ static int gfs2_dump_lockstate(struct gfs2_sbd *sdp);
 static int dump_glock(struct glock_iter *gi, struct gfs2_glock *gl);
 static void gfs2_glock_xmote_th(struct gfs2_glock *gl, struct gfs2_holder *gh);
 static void gfs2_glock_drop_th(struct gfs2_glock *gl);
+static void run_queue(struct gfs2_glock *gl);
+
 static DECLARE_RWSEM(gfs2_umount_flush_sem);
 static struct dentry *gfs2_root;
+static struct task_struct *scand_process;
+static unsigned int scand_secs = 5;
+static struct workqueue_struct *glock_workqueue;
 
 #define GFS2_GL_HASH_SHIFT      15
 #define GFS2_GL_HASH_SIZE       (1 << GFS2_GL_HASH_SHIFT)
@@ -276,6 +282,18 @@ static struct gfs2_glock *gfs2_glock_find(const struct gfs2_sbd *sdp,
         return gl;
 }
 
+static void glock_work_func(struct work_struct *work)
+{
+        struct gfs2_glock *gl = container_of(work, struct gfs2_glock, gl_work.work);
+
+        spin_lock(&gl->gl_spin);
+        if (test_and_clear_bit(GLF_PENDING_DEMOTE, &gl->gl_flags))
+                set_bit(GLF_DEMOTE, &gl->gl_flags);
+        run_queue(gl);
+        spin_unlock(&gl->gl_spin);
+        gfs2_glock_put(gl);
+}
+
 /**
  * gfs2_glock_get() - Get a glock, or create one if one doesn't exist
  * @sdp: The GFS2 superblock
@@ -315,6 +333,7 @@ int gfs2_glock_get(struct gfs2_sbd *sdp, u64 number,
         gl->gl_name = name;
         atomic_set(&gl->gl_ref, 1);
         gl->gl_state = LM_ST_UNLOCKED;
+        gl->gl_demote_state = LM_ST_EXCLUSIVE;
         gl->gl_hash = hash;
         gl->gl_owner_pid = 0;
         gl->gl_ip = 0;
@@ -323,10 +342,12 @@ int gfs2_glock_get(struct gfs2_sbd *sdp, u64 number,
         gl->gl_req_bh = NULL;
         gl->gl_vn = 0;
         gl->gl_stamp = jiffies;
+        gl->gl_tchange = jiffies;
         gl->gl_object = NULL;
         gl->gl_sbd = sdp;
         gl->gl_aspace = NULL;
         lops_init_le(&gl->gl_le, &gfs2_glock_lops);
+        INIT_DELAYED_WORK(&gl->gl_work, glock_work_func);
 
         /* If this glock protects actual on-disk data or metadata blocks,
            create a VFS inode to manage the pages/buffers holding them. */
@@ -440,6 +461,8 @@ static void wait_on_holder(struct gfs2_holder *gh)
 
 static void gfs2_demote_wake(struct gfs2_glock *gl)
 {
+        BUG_ON(!spin_is_locked(&gl->gl_spin));
+        gl->gl_demote_state = LM_ST_EXCLUSIVE;
         clear_bit(GLF_DEMOTE, &gl->gl_flags);
         smp_mb__after_clear_bit();
         wake_up_bit(&gl->gl_flags, GLF_DEMOTE);
@@ -545,12 +568,14 @@ static int rq_demote(struct gfs2_glock *gl)
                 return 0;
         }
         set_bit(GLF_LOCK, &gl->gl_flags);
-        spin_unlock(&gl->gl_spin);
         if (gl->gl_demote_state == LM_ST_UNLOCKED ||
-            gl->gl_state != LM_ST_EXCLUSIVE)
+            gl->gl_state != LM_ST_EXCLUSIVE) {
+                spin_unlock(&gl->gl_spin);
                 gfs2_glock_drop_th(gl);
-        else
+        } else {
+                spin_unlock(&gl->gl_spin);
                 gfs2_glock_xmote_th(gl, NULL);
+        }
         spin_lock(&gl->gl_spin);
 
         return 0;
@@ -679,24 +704,25 @@ static void gfs2_glmutex_unlock(struct gfs2_glock *gl)
  * practise: LM_ST_SHARED and LM_ST_UNLOCKED
  */
 
-static void handle_callback(struct gfs2_glock *gl, unsigned int state, int remote)
+static void handle_callback(struct gfs2_glock *gl, unsigned int state,
+                            int remote, unsigned long delay)
 {
+        int bit = delay ? GLF_PENDING_DEMOTE : GLF_DEMOTE;
+
         spin_lock(&gl->gl_spin);
-        if (test_and_set_bit(GLF_DEMOTE, &gl->gl_flags) == 0) {
+        set_bit(bit, &gl->gl_flags);
+        if (gl->gl_demote_state == LM_ST_EXCLUSIVE) {
                 gl->gl_demote_state = state;
                 gl->gl_demote_time = jiffies;
                 if (remote && gl->gl_ops->go_type == LM_TYPE_IOPEN &&
                     gl->gl_object) {
-                        struct inode *inode = igrab(gl->gl_object);
+                        gfs2_glock_schedule_for_reclaim(gl);
                         spin_unlock(&gl->gl_spin);
-                        if (inode) {
-                                d_prune_aliases(inode);
-                                iput(inode);
-                        }
                         return;
                 }
-        } else if (gl->gl_demote_state != LM_ST_UNLOCKED) {
-                gl->gl_demote_state = state;
+        } else if (gl->gl_demote_state != LM_ST_UNLOCKED &&
+                        gl->gl_demote_state != state) {
+                gl->gl_demote_state = LM_ST_UNLOCKED;
         }
         spin_unlock(&gl->gl_spin);
 }
@@ -723,6 +749,7 @@ static void state_change(struct gfs2_glock *gl, unsigned int new_state)
         }
 
         gl->gl_state = new_state;
+        gl->gl_tchange = jiffies;
 }
 
 /**
@@ -760,10 +787,20 @@ static void xmote_bh(struct gfs2_glock *gl, unsigned int ret)
 
         if (!gh) {
                 gl->gl_stamp = jiffies;
-                if (ret & LM_OUT_CANCELED)
+                if (ret & LM_OUT_CANCELED) {
                         op_done = 0;
-                else
+                } else {
+                        spin_lock(&gl->gl_spin);
+                        if (gl->gl_state != gl->gl_demote_state) {
+                                gl->gl_req_bh = NULL;
+                                spin_unlock(&gl->gl_spin);
+                                gfs2_glock_drop_th(gl);
+                                gfs2_glock_put(gl);
+                                return;
+                        }
                         gfs2_demote_wake(gl);
+                        spin_unlock(&gl->gl_spin);
+                }
         } else {
                 spin_lock(&gl->gl_spin);
                 list_del_init(&gh->gh_list);
@@ -799,7 +836,6 @@ out:
                 gl->gl_req_gh = NULL;
                 gl->gl_req_bh = NULL;
                 clear_bit(GLF_LOCK, &gl->gl_flags);
-                run_queue(gl);
                 spin_unlock(&gl->gl_spin);
         }
 
@@ -817,7 +853,7 @@ out:
  *
  */
 
-void gfs2_glock_xmote_th(struct gfs2_glock *gl, struct gfs2_holder *gh)
+static void gfs2_glock_xmote_th(struct gfs2_glock *gl, struct gfs2_holder *gh)
 {
         struct gfs2_sbd *sdp = gl->gl_sbd;
         int flags = gh ? gh->gh_flags : 0;
@@ -871,7 +907,6 @@ static void drop_bh(struct gfs2_glock *gl, unsigned int ret)
         gfs2_assert_warn(sdp, !ret);
 
         state_change(gl, LM_ST_UNLOCKED);
-        gfs2_demote_wake(gl);
 
         if (glops->go_inval)
                 glops->go_inval(gl, DIO_METADATA);
@@ -884,10 +919,10 @@ static void drop_bh(struct gfs2_glock *gl, unsigned int ret)
         }
 
         spin_lock(&gl->gl_spin);
+        gfs2_demote_wake(gl);
         gl->gl_req_gh = NULL;
         gl->gl_req_bh = NULL;
         clear_bit(GLF_LOCK, &gl->gl_flags);
-        run_queue(gl);
         spin_unlock(&gl->gl_spin);
 
         gfs2_glock_put(gl);
@@ -1067,24 +1102,31 @@ static void add_to_queue(struct gfs2_holder *gh)
         if (test_and_set_bit(HIF_WAIT, &gh->gh_iflags))
                 BUG();
 
-        existing = find_holder_by_owner(&gl->gl_holders, gh->gh_owner_pid);
-        if (existing) {
-                print_symbol(KERN_WARNING "original: %s\n", existing->gh_ip);
-                printk(KERN_INFO "pid : %d\n", existing->gh_owner_pid);
-                printk(KERN_INFO "lock type : %d lock state : %d\n",
-                                existing->gh_gl->gl_name.ln_type, existing->gh_gl->gl_state);
-                print_symbol(KERN_WARNING "new: %s\n", gh->gh_ip);
-                printk(KERN_INFO "pid : %d\n", gh->gh_owner_pid);
-                printk(KERN_INFO "lock type : %d lock state : %d\n",
-                                gl->gl_name.ln_type, gl->gl_state);
-                BUG();
-        }
-
-        existing = find_holder_by_owner(&gl->gl_waiters3, gh->gh_owner_pid);
-        if (existing) {
-                print_symbol(KERN_WARNING "original: %s\n", existing->gh_ip);
-                print_symbol(KERN_WARNING "new: %s\n", gh->gh_ip);
-                BUG();
+        if (!(gh->gh_flags & GL_FLOCK)) {
+                existing = find_holder_by_owner(&gl->gl_holders, 
+                                                gh->gh_owner_pid);
+                if (existing) {
+                        print_symbol(KERN_WARNING "original: %s\n", 
+                                     existing->gh_ip);
+                        printk(KERN_INFO "pid : %d\n", existing->gh_owner_pid);
+                        printk(KERN_INFO "lock type : %d lock state : %d\n",
+                               existing->gh_gl->gl_name.ln_type, 
+                               existing->gh_gl->gl_state);
+                        print_symbol(KERN_WARNING "new: %s\n", gh->gh_ip);
+                        printk(KERN_INFO "pid : %d\n", gh->gh_owner_pid);
+                        printk(KERN_INFO "lock type : %d lock state : %d\n",
+                               gl->gl_name.ln_type, gl->gl_state);
+                        BUG();
+                }
+                
+                existing = find_holder_by_owner(&gl->gl_waiters3, 
+                                                gh->gh_owner_pid);
+                if (existing) {
+                        print_symbol(KERN_WARNING "original: %s\n", 
+                                     existing->gh_ip);
+                        print_symbol(KERN_WARNING "new: %s\n", gh->gh_ip);
+                        BUG();
+                }
         }
 
         if (gh->gh_flags & LM_FLAG_PRIORITY)
@@ -1195,9 +1237,10 @@ void gfs2_glock_dq(struct gfs2_holder *gh)
 {
         struct gfs2_glock *gl = gh->gh_gl;
         const struct gfs2_glock_operations *glops = gl->gl_ops;
+        unsigned delay = 0;
 
         if (gh->gh_flags & GL_NOCACHE)
-                handle_callback(gl, LM_ST_UNLOCKED, 0);
+                handle_callback(gl, LM_ST_UNLOCKED, 0, 0);
 
         gfs2_glmutex_lock(gl);
 
@@ -1215,8 +1258,14 @@ void gfs2_glock_dq(struct gfs2_holder *gh)
         }
 
         clear_bit(GLF_LOCK, &gl->gl_flags);
-        run_queue(gl);
         spin_unlock(&gl->gl_spin);
+
+        gfs2_glock_hold(gl);
+        if (test_bit(GLF_PENDING_DEMOTE, &gl->gl_flags) &&
+            !test_bit(GLF_DEMOTE, &gl->gl_flags))
+                delay = gl->gl_ops->go_min_hold_time;
+        if (queue_delayed_work(glock_workqueue, &gl->gl_work, delay) == 0)
+                gfs2_glock_put(gl);
 }
 
 void gfs2_glock_dq_wait(struct gfs2_holder *gh)
@@ -1443,18 +1492,21 @@ static void blocking_cb(struct gfs2_sbd *sdp, struct lm_lockname *name,
                         unsigned int state)
 {
         struct gfs2_glock *gl;
+        unsigned long delay = 0;
+        unsigned long holdtime;
+        unsigned long now = jiffies;
 
         gl = gfs2_glock_find(sdp, name);
         if (!gl)
                 return;
 
-        handle_callback(gl, state, 1);
-
-        spin_lock(&gl->gl_spin);
-        run_queue(gl);
-        spin_unlock(&gl->gl_spin);
+        holdtime = gl->gl_tchange + gl->gl_ops->go_min_hold_time;
+        if (time_before(now, holdtime))
+                delay = holdtime - now;
 
-        gfs2_glock_put(gl);
+        handle_callback(gl, state, 1, delay);
+        if (queue_delayed_work(glock_workqueue, &gl->gl_work, delay) == 0)
+                gfs2_glock_put(gl);
 }
 
 /**
@@ -1495,7 +1547,8 @@ void gfs2_glock_cb(void *cb_data, unsigned int type, void *data)
                         return;
                 if (!gfs2_assert_warn(sdp, gl->gl_req_bh))
                         gl->gl_req_bh(gl, async->lc_ret);
-                gfs2_glock_put(gl);
+                if (queue_delayed_work(glock_workqueue, &gl->gl_work, 0) == 0)
+                        gfs2_glock_put(gl);
                 up_read(&gfs2_umount_flush_sem);
                 return;
         }
@@ -1588,7 +1641,7 @@ void gfs2_reclaim_glock(struct gfs2_sbd *sdp)
         if (gfs2_glmutex_trylock(gl)) {
                 if (list_empty(&gl->gl_holders) &&
                     gl->gl_state != LM_ST_UNLOCKED && demote_ok(gl))
-                        handle_callback(gl, LM_ST_UNLOCKED, 0);
+                        handle_callback(gl, LM_ST_UNLOCKED, 0, 0);
                 gfs2_glmutex_unlock(gl);
         }
 
@@ -1617,7 +1670,7 @@ static int examine_bucket(glock_examiner examiner, struct gfs2_sbd *sdp,
                 goto out;
         gl = list_entry(head->first, struct gfs2_glock, gl_list);
         while(1) {
-                if (gl->gl_sbd == sdp) {
+                if (!sdp || gl->gl_sbd == sdp) {
                         gfs2_glock_hold(gl);
                         read_unlock(gl_lock_addr(hash));
                         if (prev)
@@ -1635,6 +1688,7 @@ out:
         read_unlock(gl_lock_addr(hash));
         if (prev)
                 gfs2_glock_put(prev);
+        cond_resched();
         return has_entries;
 }
 
@@ -1663,20 +1717,6 @@ out_schedule:
 }
 
 /**
- * gfs2_scand_internal - Look for glocks and inodes to toss from memory
- * @sdp: the filesystem
- *
- */
-
-void gfs2_scand_internal(struct gfs2_sbd *sdp)
-{
-        unsigned int x;
-
-        for (x = 0; x < GFS2_GL_HASH_SIZE; x++)
-                examine_bucket(scan_glock, sdp, x);
-}
-
-/**
  * clear_glock - look at a glock and see if we can free it from glock cache
  * @gl: the glock to look at
  *
@@ -1701,7 +1741,7 @@ static void clear_glock(struct gfs2_glock *gl)
         if (gfs2_glmutex_trylock(gl)) {
                 if (list_empty(&gl->gl_holders) &&
                     gl->gl_state != LM_ST_UNLOCKED)
-                        handle_callback(gl, LM_ST_UNLOCKED, 0);
+                        handle_callback(gl, LM_ST_UNLOCKED, 0, 0);
                 gfs2_glmutex_unlock(gl);
         }
 }
@@ -1843,7 +1883,7 @@ static int dump_glock(struct glock_iter *gi, struct gfs2_glock *gl)
 
         spin_lock(&gl->gl_spin);
 
-        print_dbg(gi, "Glock 0x%p (%u, %llu)\n", gl, gl->gl_name.ln_type,
+        print_dbg(gi, "Glock 0x%p (%u, 0x%llx)\n", gl, gl->gl_name.ln_type,
                    (unsigned long long)gl->gl_name.ln_number);
         print_dbg(gi, "  gl_flags =");
         for (x = 0; x < 32; x++) {
@@ -1963,6 +2003,35 @@ static int gfs2_dump_lockstate(struct gfs2_sbd *sdp)
         return error;
 }
 
+/**
+ * gfs2_scand - Look for cached glocks and inodes to toss from memory
+ * @sdp: Pointer to GFS2 superblock
+ *
+ * One of these daemons runs, finding candidates to add to sd_reclaim_list.
+ * See gfs2_glockd()
+ */
+
+static int gfs2_scand(void *data)
+{
+        unsigned x;
+        unsigned delay;
+
+        while (!kthread_should_stop()) {
+                for (x = 0; x < GFS2_GL_HASH_SIZE; x++)
+                        examine_bucket(scan_glock, NULL, x);
+                if (freezing(current))
+                        refrigerator();
+                delay = scand_secs;
+                if (delay < 1)
+                        delay = 1;
+                schedule_timeout_interruptible(delay * HZ);
+        }
+
+        return 0;
+}
+
+
+
 int __init gfs2_glock_init(void)
 {
         unsigned i;
@@ -1974,52 +2043,69 @@ int __init gfs2_glock_init(void)
                 rwlock_init(&gl_hash_locks[i]);
         }
 #endif
+
+        scand_process = kthread_run(gfs2_scand, NULL, "gfs2_scand");
+        if (IS_ERR(scand_process))
+                return PTR_ERR(scand_process);
+
+        glock_workqueue = create_workqueue("glock_workqueue");
+        if (IS_ERR(glock_workqueue)) {
+                kthread_stop(scand_process);
+                return PTR_ERR(glock_workqueue);
+        }
+
         return 0;
 }
 
+void gfs2_glock_exit(void)
+{
+        destroy_workqueue(glock_workqueue);
+        kthread_stop(scand_process);
+}
+
+module_param(scand_secs, uint, S_IRUGO|S_IWUSR);
+MODULE_PARM_DESC(scand_secs, "The number of seconds between scand runs");
+
 static int gfs2_glock_iter_next(struct glock_iter *gi)
 {
+        struct gfs2_glock *gl;
+
+restart:
         read_lock(gl_lock_addr(gi->hash));
-        while (1) {
-                if (!gi->hb_list) {  /* If we don't have a hash bucket yet */
-                        gi->hb_list = &gl_hash_table[gi->hash].hb_list;
-                        if (hlist_empty(gi->hb_list)) {
-                                read_unlock(gl_lock_addr(gi->hash));
-                                gi->hash++;
-                                read_lock(gl_lock_addr(gi->hash));
-                                gi->hb_list = NULL;
-                                if (gi->hash >= GFS2_GL_HASH_SIZE) {
-                                        read_unlock(gl_lock_addr(gi->hash));
-                                        return 1;
-                                }
-                                else
-                                        continue;
-                        }
-                        if (!hlist_empty(gi->hb_list)) {
-                                gi->gl = list_entry(gi->hb_list->first,
-                                                    struct gfs2_glock,
-                                                    gl_list);
-                        }
-                } else {
-                        if (gi->gl->gl_list.next == NULL) {
-                                read_unlock(gl_lock_addr(gi->hash));
-                                gi->hash++;
-                                read_lock(gl_lock_addr(gi->hash));
-                                gi->hb_list = NULL;
-                                continue;
-                        }
-                        gi->gl = list_entry(gi->gl->gl_list.next,
-                                            struct gfs2_glock, gl_list);
-                }
+        gl = gi->gl;
+        if (gl) {
+                gi->gl = hlist_entry(gl->gl_list.next,
+                                     struct gfs2_glock, gl_list);
                 if (gi->gl)
-                        break;
+                        gfs2_glock_hold(gi->gl);
         }
         read_unlock(gl_lock_addr(gi->hash));
+        if (gl)
+                gfs2_glock_put(gl);
+        if (gl && gi->gl == NULL)
+                gi->hash++;
+        while(gi->gl == NULL) {
+                if (gi->hash >= GFS2_GL_HASH_SIZE)
+                        return 1;
+                read_lock(gl_lock_addr(gi->hash));
+                gi->gl = hlist_entry(gl_hash_table[gi->hash].hb_list.first,
+                                     struct gfs2_glock, gl_list);
+                if (gi->gl)
+                        gfs2_glock_hold(gi->gl);
+                read_unlock(gl_lock_addr(gi->hash));
+                gi->hash++;
+        }
+
+        if (gi->sdp != gi->gl->gl_sbd)
+                goto restart;
+
         return 0;
 }
 
 static void gfs2_glock_iter_free(struct glock_iter *gi)
 {
+        if (gi->gl)
+                gfs2_glock_put(gi->gl);
         kfree(gi);
 }
 
@@ -2033,9 +2119,8 @@ static struct glock_iter *gfs2_glock_iter_init(struct gfs2_sbd *sdp)
 
         gi->sdp = sdp;
         gi->hash = 0;
-        gi->gl = NULL;
-        gi->hb_list = NULL;
         gi->seq = NULL;
+        gi->gl = NULL;
         memset(gi->string, 0, sizeof(gi->string));
 
         if (gfs2_glock_iter_next(gi)) {
@@ -2055,7 +2140,7 @@ static void *gfs2_glock_seq_start(struct seq_file *file, loff_t *pos)
         if (!gi)
                 return NULL;
 
-        while (n--) {
+        while(n--) {
                 if (gfs2_glock_iter_next(gi)) {
                         gfs2_glock_iter_free(gi);
                         return NULL;
@@ -2082,7 +2167,9 @@ static void *gfs2_glock_seq_next(struct seq_file *file, void *iter_ptr,
 
 static void gfs2_glock_seq_stop(struct seq_file *file, void *iter_ptr)
 {
-        /* nothing for now */
+        struct glock_iter *gi = iter_ptr;
+        if (gi)
+                gfs2_glock_iter_free(gi);
 }
 
 static int gfs2_glock_seq_show(struct seq_file *file, void *iter_ptr)
@@ -2095,7 +2182,7 @@ static int gfs2_glock_seq_show(struct seq_file *file, void *iter_ptr)
         return 0;
 }
 
-static struct seq_operations gfs2_glock_seq_ops = {
+static const struct seq_operations gfs2_glock_seq_ops = {
         .start = gfs2_glock_seq_start,
         .next  = gfs2_glock_seq_next,
         .stop  = gfs2_glock_seq_stop,