nilfs2: change sc_timer from a pointer to an embedded one in struct nilfs_sc_info

In nilfs_segctor_thread(), timer is a local variable allocated on stack. Its
address can't be set to sci->sc_timer and passed in several procedures.

It works now by chance, just because other procedures are called by
nilfs_segctor_thread() directly or indirectly and the stack hasn't been
deallocated yet.

Signed-off-by: Li Hong <lihong.hi@gmail.com>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>

diff --git a/fs/nilfs2/segment.c b/fs/nilfs2/segment.c
index 89a15f4bfeb969671e85dccb79189f301982e46c..8b4e280b96b4f1026e6a3609ed19678e94cfe4c9 100644 (file)
--- a/fs/nilfs2/segment.c
+++ b/fs/nilfs2/segment.c
@@ -2159,9 +2159,9 @@ static int nilfs_segctor_do_construct(struct nilfs_sc_info *sci, int mode)
 static void nilfs_segctor_start_timer(struct nilfs_sc_info *sci)
 {
        spin_lock(&sci->sc_state_lock);
-       if (sci->sc_timer && !(sci->sc_state & NILFS_SEGCTOR_COMMIT)) {
-               sci->sc_timer->expires = jiffies + sci->sc_interval;
-               add_timer(sci->sc_timer);
+       if (!(sci->sc_state & NILFS_SEGCTOR_COMMIT)) {
+               sci->sc_timer.expires = jiffies + sci->sc_interval;
+               add_timer(&sci->sc_timer);
                sci->sc_state |= NILFS_SEGCTOR_COMMIT;
        }
        spin_unlock(&sci->sc_state_lock);
@@ -2366,9 +2366,7 @@ static void nilfs_segctor_accept(struct nilfs_sc_info *sci)
        spin_lock(&sci->sc_state_lock);
        sci->sc_seq_accepted = sci->sc_seq_request;
        spin_unlock(&sci->sc_state_lock);
-
-       if (sci->sc_timer)
-               del_timer_sync(sci->sc_timer);
+       del_timer_sync(&sci->sc_timer);
 }
 
 /**
@@ -2394,9 +2392,9 @@ static void nilfs_segctor_notify(struct nilfs_sc_info *sci, int mode, int err)
                        sci->sc_flush_request &= ~FLUSH_DAT_BIT;
 
                /* re-enable timer if checkpoint creation was not done */
-               if (sci->sc_timer && (sci->sc_state & NILFS_SEGCTOR_COMMIT) &&
-                   time_before(jiffies, sci->sc_timer->expires))
-                       add_timer(sci->sc_timer);
+               if ((sci->sc_state & NILFS_SEGCTOR_COMMIT) &&
+                   time_before(jiffies, sci->sc_timer.expires))
+                       add_timer(&sci->sc_timer);
        }
        spin_unlock(&sci->sc_state_lock);
 }
@@ -2575,13 +2573,10 @@ static int nilfs_segctor_thread(void *arg)
 {
        struct nilfs_sc_info *sci = (struct nilfs_sc_info *)arg;
        struct the_nilfs *nilfs = sci->sc_sbi->s_nilfs;
-       struct timer_list timer;
        int timeout = 0;
 
-       init_timer(&timer);
-       timer.data = (unsigned long)current;
-       timer.function = nilfs_construction_timeout;
-       sci->sc_timer = &timer;
+       sci->sc_timer.data = (unsigned long)current;
+       sci->sc_timer.function = nilfs_construction_timeout;
 
        /* start sync. */
        sci->sc_task = current;
@@ -2630,7 +2625,7 @@ static int nilfs_segctor_thread(void *arg)
                        should_sleep = 0;
                else if (sci->sc_state & NILFS_SEGCTOR_COMMIT)
                        should_sleep = time_before(jiffies,
-                                                  sci->sc_timer->expires);
+                                       sci->sc_timer.expires);
 
                if (should_sleep) {
                        spin_unlock(&sci->sc_state_lock);
@@ -2639,7 +2634,7 @@ static int nilfs_segctor_thread(void *arg)
                }
                finish_wait(&sci->sc_wait_daemon, &wait);
                timeout = ((sci->sc_state & NILFS_SEGCTOR_COMMIT) &&
-                          time_after_eq(jiffies, sci->sc_timer->expires));
+                          time_after_eq(jiffies, sci->sc_timer.expires));
 
                if (nilfs_sb_dirty(nilfs) && nilfs_sb_need_update(nilfs))
                        set_nilfs_discontinued(nilfs);
@@ -2648,8 +2643,6 @@ static int nilfs_segctor_thread(void *arg)
 
  end_thread:
        spin_unlock(&sci->sc_state_lock);
-       del_timer_sync(sci->sc_timer);
-       sci->sc_timer = NULL;
 
        /* end sync. */
        sci->sc_task = NULL;
@@ -2708,6 +2701,7 @@ static struct nilfs_sc_info *nilfs_segctor_new(struct nilfs_sb_info *sbi)
        INIT_LIST_HEAD(&sci->sc_write_logs);
        INIT_LIST_HEAD(&sci->sc_gc_inodes);
        INIT_LIST_HEAD(&sci->sc_copied_buffers);
+       init_timer(&sci->sc_timer);
 
        sci->sc_interval = HZ * NILFS_SC_DEFAULT_TIMEOUT;
        sci->sc_mjcp_freq = HZ * NILFS_SC_DEFAULT_SR_FREQ;
@@ -2774,6 +2768,7 @@ static void nilfs_segctor_destroy(struct nilfs_sc_info *sci)
 
        down_write(&sbi->s_nilfs->ns_segctor_sem);
 
+       del_timer_sync(&sci->sc_timer);
        kfree(sci);
 }
 

diff --git a/fs/nilfs2/segment.h b/fs/nilfs2/segment.h
index 7aca765326831f1192dafc1c7b4ced25da04bef5..dca142361ccfcac8f038453ec689ee61a97012fa 100644 (file)
--- a/fs/nilfs2/segment.h
+++ b/fs/nilfs2/segment.h
@@ -177,7 +177,7 @@ struct nilfs_sc_info {
        unsigned long           sc_lseg_stime;  /* in 1/HZ seconds */
        unsigned long           sc_watermark;
 
-       struct timer_list      *sc_timer;
+       struct timer_list       sc_timer;
        struct task_struct     *sc_task;
 };