Merge branch 'upstream-jeff' of git://git.kernel.org/pub/scm/linux/kernel/git/romieu...
[cascardo/linux.git] / fs / gfs2 / glock.c
index 3f0974e..a37efe4 100644 (file)
 #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;
 }
 
@@ -1662,20 +1716,6 @@ out_schedule:
        gfs2_glock_schedule_for_reclaim(gl);
 }
 
-/**
- * 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,