1 files changed, 39 insertions, 62 deletions

diff --git a/fs/btrfs/locking.c b/fs/btrfs/locking.c
index 870528d87526..0035851d72b0 100644
--- a/fs/btrfs/locking.c
+++ b/fs/btrfs/locking.c
@@ -8,11 +8,10 @@
 #include <linux/spinlock.h>
 #include <linux/page-flags.h>
 #include <asm/bug.h>
-#include "misc.h"
+#include <trace/events/btrfs.h>
 #include "ctree.h"
 #include "extent_io.h"
 #include "locking.h"
-#include "accessors.h"
 
 /*
  * Lockdep class keys for extent_buffer->lock's in this root.  For a given
@@ -57,8 +56,8 @@
 
 static struct btrfs_lockdep_keyset {
 	u64			id;		/* root objectid */
-	/* Longest entry: btrfs-free-space-00 */
-	char			names[BTRFS_MAX_LEVEL][20];
+	/* Longest entry: btrfs-block-group-00 */
+	char			names[BTRFS_MAX_LEVEL][24];
 	struct lock_class_key	keys[BTRFS_MAX_LEVEL];
 } btrfs_lockdep_keysets[] = {
 	{ .id = BTRFS_ROOT_TREE_OBJECTID,	DEFINE_NAME("root")	},
@@ -72,6 +71,8 @@ static struct btrfs_lockdep_keyset {
 	{ .id = BTRFS_DATA_RELOC_TREE_OBJECTID,	DEFINE_NAME("dreloc")	},
 	{ .id = BTRFS_UUID_TREE_OBJECTID,	DEFINE_NAME("uuid")	},
 	{ .id = BTRFS_FREE_SPACE_TREE_OBJECTID,	DEFINE_NAME("free-space") },
+	{ .id = BTRFS_BLOCK_GROUP_TREE_OBJECTID, DEFINE_NAME("block-group") },
+	{ .id = BTRFS_RAID_STRIPE_TREE_OBJECTID, DEFINE_NAME("raid-stripe") },
 	{ .id = 0,				DEFINE_NAME("tree")	},
 };
 
@@ -82,7 +83,7 @@ void btrfs_set_buffer_lockdep_class(u64 objectid, struct extent_buffer *eb, int
 {
 	struct btrfs_lockdep_keyset *ks;
 
-	BUG_ON(level >= ARRAY_SIZE(ks->keys));
+	ASSERT(level < ARRAY_SIZE(ks->keys));
 
 	/* Find the matching keyset, id 0 is the default entry */
 	for (ks = btrfs_lockdep_keysets; ks->id; ks++)
@@ -95,12 +96,21 @@ void btrfs_set_buffer_lockdep_class(u64 objectid, struct extent_buffer *eb, int
 void btrfs_maybe_reset_lockdep_class(struct btrfs_root *root, struct extent_buffer *eb)
 {
 	if (test_bit(BTRFS_ROOT_RESET_LOCKDEP_CLASS, &root->state))
-		btrfs_set_buffer_lockdep_class(root->root_key.objectid,
+		btrfs_set_buffer_lockdep_class(btrfs_root_id(root),
 					       eb, btrfs_header_level(eb));
 }
 
 #endif
 
+#ifdef CONFIG_BTRFS_DEBUG
+static void btrfs_set_eb_lock_owner(struct extent_buffer *eb, pid_t owner)
+{
+	eb->lock_owner = owner;
+}
+#else
+static void btrfs_set_eb_lock_owner(struct extent_buffer *eb, pid_t owner) { }
+#endif
+
 /*
  * Extent buffer locking
  * =====================
@@ -118,14 +128,14 @@ void btrfs_maybe_reset_lockdep_class(struct btrfs_root *root, struct extent_buff
  */
 
 /*
- * __btrfs_tree_read_lock - lock extent buffer for read
+ * btrfs_tree_read_lock_nested - lock extent buffer for read
  * @eb:		the eb to be locked
  * @nest:	the nesting level to be used for lockdep
  *
  * This takes the read lock on the extent buffer, using the specified nesting
  * level for lockdep purposes.
  */
-void __btrfs_tree_read_lock(struct extent_buffer *eb, enum btrfs_lock_nesting nest)
+void btrfs_tree_read_lock_nested(struct extent_buffer *eb, enum btrfs_lock_nesting nest)
 {
 	u64 start_ns = 0;
 
@@ -136,38 +146,18 @@ void __btrfs_tree_read_lock(struct extent_buffer *eb, enum btrfs_lock_nesting ne
 	trace_btrfs_tree_read_lock(eb, start_ns);
 }
 
-void btrfs_tree_read_lock(struct extent_buffer *eb)
-{
-	__btrfs_tree_read_lock(eb, BTRFS_NESTING_NORMAL);
-}
-
 /*
  * Try-lock for read.
  *
- * Return 1 if the rwlock has been taken, 0 otherwise
+ * Return true if the rwlock has been taken, false otherwise
  */
-int btrfs_try_tree_read_lock(struct extent_buffer *eb)
+bool btrfs_try_tree_read_lock(struct extent_buffer *eb)
 {
 	if (down_read_trylock(&eb->lock)) {
 		trace_btrfs_try_tree_read_lock(eb);
-		return 1;
-	}
-	return 0;
-}
-
-/*
- * Try-lock for write.
- *
- * Return 1 if the rwlock has been taken, 0 otherwise
- */
-int btrfs_try_tree_write_lock(struct extent_buffer *eb)
-{
-	if (down_write_trylock(&eb->lock)) {
-		eb->lock_owner = current->pid;
-		trace_btrfs_try_tree_write_lock(eb);
-		return 1;
+		return true;
 	}
-	return 0;
+	return false;
 }
 
 /*
@@ -180,13 +170,14 @@ void btrfs_tree_read_unlock(struct extent_buffer *eb)
 }
 
 /*
- * __btrfs_tree_lock - lock eb for write
+ * Lock eb for write.
+ *
  * @eb:		the eb to lock
  * @nest:	the nesting to use for the lock
  *
  * Returns with the eb->lock write locked.
  */
-void __btrfs_tree_lock(struct extent_buffer *eb, enum btrfs_lock_nesting nest)
+void btrfs_tree_lock_nested(struct extent_buffer *eb, enum btrfs_lock_nesting nest)
 	__acquires(&eb->lock)
 {
 	u64 start_ns = 0;
@@ -195,22 +186,17 @@ void __btrfs_tree_lock(struct extent_buffer *eb, enum btrfs_lock_nesting nest)
 		start_ns = ktime_get_ns();
 
 	down_write_nested(&eb->lock, nest);
-	eb->lock_owner = current->pid;
+	btrfs_set_eb_lock_owner(eb, current->pid);
 	trace_btrfs_tree_lock(eb, start_ns);
 }
 
-void btrfs_tree_lock(struct extent_buffer *eb)
-{
-	__btrfs_tree_lock(eb, BTRFS_NESTING_NORMAL);
-}
-
 /*
  * Release the write lock.
  */
 void btrfs_tree_unlock(struct extent_buffer *eb)
 {
 	trace_btrfs_tree_unlock(eb);
-	eb->lock_owner = 0;
+	btrfs_set_eb_lock_owner(eb, 0);
 	up_write(&eb->lock);
 }
 
@@ -325,24 +311,12 @@ struct extent_buffer *btrfs_try_read_lock_root_node(struct btrfs_root *root)
  * acquire the lock.
  */
 
-int btrfs_drew_lock_init(struct btrfs_drew_lock *lock)
+void btrfs_drew_lock_init(struct btrfs_drew_lock *lock)
 {
-	int ret;
-
-	ret = percpu_counter_init(&lock->writers, 0, GFP_KERNEL);
-	if (ret)
-		return ret;
-
 	atomic_set(&lock->readers, 0);
+	atomic_set(&lock->writers, 0);
 	init_waitqueue_head(&lock->pending_readers);
 	init_waitqueue_head(&lock->pending_writers);
-
-	return 0;
-}
-
-void btrfs_drew_lock_destroy(struct btrfs_drew_lock *lock)
-{
-	percpu_counter_destroy(&lock->writers);
 }
 
 /* Return true if acquisition is successful, false otherwise */
@@ -351,10 +325,10 @@ bool btrfs_drew_try_write_lock(struct btrfs_drew_lock *lock)
 	if (atomic_read(&lock->readers))
 		return false;
 
-	percpu_counter_inc(&lock->writers);
+	atomic_inc(&lock->writers);
 
 	/* Ensure writers count is updated before we check for pending readers */
-	smp_mb();
+	smp_mb__after_atomic();
 	if (atomic_read(&lock->readers)) {
 		btrfs_drew_write_unlock(lock);
 		return false;
@@ -374,8 +348,12 @@ void btrfs_drew_write_lock(struct btrfs_drew_lock *lock)
 
 void btrfs_drew_write_unlock(struct btrfs_drew_lock *lock)
 {
-	percpu_counter_dec(&lock->writers);
-	cond_wake_up(&lock->pending_readers);
+	/*
+	 * atomic_dec_and_test() implies a full barrier, so woken up readers are
+	 * guaranteed to see the decrement.
+	 */
+	if (atomic_dec_and_test(&lock->writers))
+		wake_up(&lock->pending_readers);
 }
 
 void btrfs_drew_read_lock(struct btrfs_drew_lock *lock)
@@ -383,15 +361,14 @@ void btrfs_drew_read_lock(struct btrfs_drew_lock *lock)
 	atomic_inc(&lock->readers);
 
 	/*
-	 * Ensure the pending reader count is perceieved BEFORE this reader
+	 * Ensure the pending reader count is perceived BEFORE this reader
 	 * goes to sleep in case of active writers. This guarantees new writers
 	 * won't be allowed and that the current reader will be woken up when
 	 * the last active writer finishes its jobs.
 	 */
 	smp_mb__after_atomic();
 
-	wait_event(lock->pending_readers,
-		   percpu_counter_sum(&lock->writers) == 0);
+	wait_event(lock->pending_readers, atomic_read(&lock->writers) == 0);
 }
 
 void btrfs_drew_read_unlock(struct btrfs_drew_lock *lock)