btrfs: move leak debug code to functions

Clean up the leak debugging in extent_io.c by moving
the debug code into functions.  This also removes the
list_heads used for debugging from the extent_buffer
and extent_state structures when debug is not enabled.

Since we need a global debug config to do that last
part, implement CONFIG_BTRFS_DEBUG to accommodate.

Thanks to Dave Sterba for the Kconfig bit.

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Reviewed-by: David Sterba <dsterba@suse.cz>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>

diff --git a/fs/btrfs/Kconfig b/fs/btrfs/Kconfig
index 0f5374c..2b3b832 100644 (file)
--- a/fs/btrfs/Kconfig
+++ b/fs/btrfs/Kconfig
@@ -63,3 +63,12 @@ config BTRFS_FS_RUN_SANITY_TESTS
 
          If unsure, say N.
 
+config BTRFS_DEBUG
+       bool "Btrfs debugging support"
+       depends on BTRFS_FS
+       help
+         Enable run-time debugging support for the btrfs filesystem. This may
+         enable additional and expensive checks with negative impact on
+         performance, or export extra information via sysfs.
+
+         If unsure, say N.

diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index d9a82f2..f110d12 100644 (file)
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -24,12 +24,62 @@
 static struct kmem_cache *extent_state_cache;
 static struct kmem_cache *extent_buffer_cache;
 
+#ifdef CONFIG_BTRFS_DEBUG
 static LIST_HEAD(buffers);
 static LIST_HEAD(states);
 
-#define LEAK_DEBUG 0
-#if LEAK_DEBUG
 static DEFINE_SPINLOCK(leak_lock);
+
+static inline
+void btrfs_leak_debug_add(struct list_head *new, struct list_head *head)
+{
+       unsigned long flags;
+
+       spin_lock_irqsave(&leak_lock, flags);
+       list_add(new, head);
+       spin_unlock_irqrestore(&leak_lock, flags);
+}
+
+static inline
+void btrfs_leak_debug_del(struct list_head *entry)
+{
+       unsigned long flags;
+
+       spin_lock_irqsave(&leak_lock, flags);
+       list_del(entry);
+       spin_unlock_irqrestore(&leak_lock, flags);
+}
+
+static inline
+void btrfs_leak_debug_check(void)
+{
+       struct extent_state *state;
+       struct extent_buffer *eb;
+
+       while (!list_empty(&states)) {
+               state = list_entry(states.next, struct extent_state, leak_list);
+               printk(KERN_ERR "btrfs state leak: start %llu end %llu "
+                      "state %lu in tree %p refs %d\n",
+                      (unsigned long long)state->start,
+                      (unsigned long long)state->end,
+                      state->state, state->tree, atomic_read(&state->refs));
+               list_del(&state->leak_list);
+               kmem_cache_free(extent_state_cache, state);
+       }
+
+       while (!list_empty(&buffers)) {
+               eb = list_entry(buffers.next, struct extent_buffer, leak_list);
+               printk(KERN_ERR "btrfs buffer leak start %llu len %lu "
+                      "refs %d\n", (unsigned long long)eb->start,
+                      eb->len, atomic_read(&eb->refs));
+               list_del(&eb->leak_list);
+               kmem_cache_free(extent_buffer_cache, eb);
+       }
+}
+#else
+#define btrfs_leak_debug_add(new, head)        do {} while (0)
+#define btrfs_leak_debug_del(entry)    do {} while (0)
+#define btrfs_leak_debug_check()       do {} while (0)
 #endif
 
 #define BUFFER_LRU_MAX 64
@@ -84,29 +134,7 @@ free_state_cache:
 
 void extent_io_exit(void)
 {
-       struct extent_state *state;
-       struct extent_buffer *eb;
-
-       while (!list_empty(&states)) {
-               state = list_entry(states.next, struct extent_state, leak_list);
-               printk(KERN_ERR "btrfs state leak: start %llu end %llu "
-                      "state %lu in tree %p refs %d\n",
-                      (unsigned long long)state->start,
-                      (unsigned long long)state->end,
-                      state->state, state->tree, atomic_read(&state->refs));
-               list_del(&state->leak_list);
-               kmem_cache_free(extent_state_cache, state);
-
-       }
-
-       while (!list_empty(&buffers)) {
-               eb = list_entry(buffers.next, struct extent_buffer, leak_list);
-               printk(KERN_ERR "btrfs buffer leak start %llu len %lu "
-                      "refs %d\n", (unsigned long long)eb->start,
-                      eb->len, atomic_read(&eb->refs));
-               list_del(&eb->leak_list);
-               kmem_cache_free(extent_buffer_cache, eb);
-       }
+       btrfs_leak_debug_check();
 
        /*
         * Make sure all delayed rcu free are flushed before we
@@ -134,9 +162,6 @@ void extent_io_tree_init(struct extent_io_tree *tree,
 static struct extent_state *alloc_extent_state(gfp_t mask)
 {
        struct extent_state *state;
-#if LEAK_DEBUG
-       unsigned long flags;
-#endif
 
        state = kmem_cache_alloc(extent_state_cache, mask);
        if (!state)
@@ -144,11 +169,7 @@ static struct extent_state *alloc_extent_state(gfp_t mask)
        state->state = 0;
        state->private = 0;
        state->tree = NULL;
-#if LEAK_DEBUG
-       spin_lock_irqsave(&leak_lock, flags);
-       list_add(&state->leak_list, &states);
-       spin_unlock_irqrestore(&leak_lock, flags);
-#endif
+       btrfs_leak_debug_add(&state->leak_list, &states);
        atomic_set(&state->refs, 1);
        init_waitqueue_head(&state->wq);
        trace_alloc_extent_state(state, mask, _RET_IP_);
@@ -160,15 +181,8 @@ void free_extent_state(struct extent_state *state)
        if (!state)
                return;
        if (atomic_dec_and_test(&state->refs)) {
-#if LEAK_DEBUG
-               unsigned long flags;
-#endif
                WARN_ON(state->tree);
-#if LEAK_DEBUG
-               spin_lock_irqsave(&leak_lock, flags);
-               list_del(&state->leak_list);
-               spin_unlock_irqrestore(&leak_lock, flags);
-#endif
+               btrfs_leak_debug_del(&state->leak_list);
                trace_free_extent_state(state, _RET_IP_);
                kmem_cache_free(extent_state_cache, state);
        }
@@ -4065,12 +4079,7 @@ out:
 
 static void __free_extent_buffer(struct extent_buffer *eb)
 {
-#if LEAK_DEBUG
-       unsigned long flags;
-       spin_lock_irqsave(&leak_lock, flags);
-       list_del(&eb->leak_list);
-       spin_unlock_irqrestore(&leak_lock, flags);
-#endif
+       btrfs_leak_debug_del(&eb->leak_list);
        kmem_cache_free(extent_buffer_cache, eb);
 }
 
@@ -4080,9 +4089,6 @@ static struct extent_buffer *__alloc_extent_buffer(struct extent_io_tree *tree,
                                                   gfp_t mask)
 {
        struct extent_buffer *eb = NULL;
-#if LEAK_DEBUG
-       unsigned long flags;
-#endif
 
        eb = kmem_cache_zalloc(extent_buffer_cache, mask);
        if (eb == NULL)
@@ -4102,11 +4108,8 @@ static struct extent_buffer *__alloc_extent_buffer(struct extent_io_tree *tree,
        init_waitqueue_head(&eb->write_lock_wq);
        init_waitqueue_head(&eb->read_lock_wq);
 
-#if LEAK_DEBUG
-       spin_lock_irqsave(&leak_lock, flags);
-       list_add(&eb->leak_list, &buffers);
-       spin_unlock_irqrestore(&leak_lock, flags);
-#endif
+       btrfs_leak_debug_add(&eb->leak_list, &buffers);
+
        spin_lock_init(&eb->refs_lock);
        atomic_set(&eb->refs, 1);
        atomic_set(&eb->io_pages, 0);

diff --git a/fs/btrfs/extent_io.h b/fs/btrfs/extent_io.h
index fa86861..59d883b 100644 (file)
--- a/fs/btrfs/extent_io.h
+++ b/fs/btrfs/extent_io.h
@@ -116,7 +116,9 @@ struct extent_state {
        /* for use by the FS */
        u64 private;
 
+#ifdef CONFIG_BTRFS_DEBUG
        struct list_head leak_list;
+#endif
 };
 
 #define INLINE_EXTENT_BUFFER_PAGES 16
@@ -132,7 +134,6 @@ struct extent_buffer {
        atomic_t refs;
        atomic_t io_pages;
        int read_mirror;
-       struct list_head leak_list;
        struct rcu_head rcu_head;
        pid_t lock_owner;
 
@@ -159,6 +160,9 @@ struct extent_buffer {
        wait_queue_head_t read_lock_wq;
        wait_queue_head_t lock_wq;
        struct page *pages[INLINE_EXTENT_BUFFER_PAGES];
+#ifdef CONFIG_BTRFS_DEBUG
+       struct list_head leak_list;
+#endif
 };
 
 static inline void extent_set_compress_type(unsigned long *bio_flags,