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Diffstat (limited to 'fs/btrfs/locking.c')
-rw-r--r--fs/btrfs/locking.c108
1 files changed, 53 insertions, 55 deletions
diff --git a/fs/btrfs/locking.c b/fs/btrfs/locking.c
index 1da768e5ef75..82b84e4daad1 100644
--- a/fs/btrfs/locking.c
+++ b/fs/btrfs/locking.c
@@ -14,43 +14,58 @@
static void btrfs_assert_tree_read_locked(struct extent_buffer *eb);
-/*
- * if we currently have a spinning reader or writer lock
- * (indicated by the rw flag) this will bump the count
- * of blocking holders and drop the spinlock.
- */
-void btrfs_set_lock_blocking_rw(struct extent_buffer *eb, int rw)
+void btrfs_set_lock_blocking_read(struct extent_buffer *eb)
{
/*
- * no lock is required. The lock owner may change if
- * we have a read lock, but it won't change to or away
- * from us. If we have the write lock, we are the owner
- * and it'll never change.
+ * No lock is required. The lock owner may change if we have a read
+ * lock, but it won't change to or away from us. If we have the write
+ * lock, we are the owner and it'll never change.
*/
if (eb->lock_nested && current->pid == eb->lock_owner)
return;
- if (rw == BTRFS_WRITE_LOCK) {
- if (atomic_read(&eb->blocking_writers) == 0) {
- WARN_ON(atomic_read(&eb->spinning_writers) != 1);
- atomic_dec(&eb->spinning_writers);
- btrfs_assert_tree_locked(eb);
- atomic_inc(&eb->blocking_writers);
- write_unlock(&eb->lock);
- }
- } else if (rw == BTRFS_READ_LOCK) {
- btrfs_assert_tree_read_locked(eb);
- atomic_inc(&eb->blocking_readers);
- WARN_ON(atomic_read(&eb->spinning_readers) == 0);
- atomic_dec(&eb->spinning_readers);
- read_unlock(&eb->lock);
+ btrfs_assert_tree_read_locked(eb);
+ atomic_inc(&eb->blocking_readers);
+ WARN_ON(atomic_read(&eb->spinning_readers) == 0);
+ atomic_dec(&eb->spinning_readers);
+ read_unlock(&eb->lock);
+}
+
+void btrfs_set_lock_blocking_write(struct extent_buffer *eb)
+{
+ /*
+ * No lock is required. The lock owner may change if we have a read
+ * lock, but it won't change to or away from us. If we have the write
+ * lock, we are the owner and it'll never change.
+ */
+ if (eb->lock_nested && current->pid == eb->lock_owner)
+ return;
+ if (atomic_read(&eb->blocking_writers) == 0) {
+ WARN_ON(atomic_read(&eb->spinning_writers) != 1);
+ atomic_dec(&eb->spinning_writers);
+ btrfs_assert_tree_locked(eb);
+ atomic_inc(&eb->blocking_writers);
+ write_unlock(&eb->lock);
}
}
-/*
- * if we currently have a blocking lock, take the spinlock
- * and drop our blocking count
- */
-void btrfs_clear_lock_blocking_rw(struct extent_buffer *eb, int rw)
+void btrfs_clear_lock_blocking_read(struct extent_buffer *eb)
+{
+ /*
+ * No lock is required. The lock owner may change if we have a read
+ * lock, but it won't change to or away from us. If we have the write
+ * lock, we are the owner and it'll never change.
+ */
+ if (eb->lock_nested && current->pid == eb->lock_owner)
+ return;
+ BUG_ON(atomic_read(&eb->blocking_readers) == 0);
+ read_lock(&eb->lock);
+ atomic_inc(&eb->spinning_readers);
+ /* atomic_dec_and_test implies a barrier */
+ if (atomic_dec_and_test(&eb->blocking_readers))
+ cond_wake_up_nomb(&eb->read_lock_wq);
+}
+
+void btrfs_clear_lock_blocking_write(struct extent_buffer *eb)
{
/*
* no lock is required. The lock owner may change if
@@ -60,23 +75,13 @@ void btrfs_clear_lock_blocking_rw(struct extent_buffer *eb, int rw)
*/
if (eb->lock_nested && current->pid == eb->lock_owner)
return;
-
- if (rw == BTRFS_WRITE_LOCK_BLOCKING) {
- BUG_ON(atomic_read(&eb->blocking_writers) != 1);
- write_lock(&eb->lock);
- WARN_ON(atomic_read(&eb->spinning_writers));
- atomic_inc(&eb->spinning_writers);
- /* atomic_dec_and_test implies a barrier */
- if (atomic_dec_and_test(&eb->blocking_writers))
- cond_wake_up_nomb(&eb->write_lock_wq);
- } else if (rw == BTRFS_READ_LOCK_BLOCKING) {
- BUG_ON(atomic_read(&eb->blocking_readers) == 0);
- read_lock(&eb->lock);
- atomic_inc(&eb->spinning_readers);
- /* atomic_dec_and_test implies a barrier */
- if (atomic_dec_and_test(&eb->blocking_readers))
- cond_wake_up_nomb(&eb->read_lock_wq);
- }
+ BUG_ON(atomic_read(&eb->blocking_writers) != 1);
+ write_lock(&eb->lock);
+ WARN_ON(atomic_read(&eb->spinning_writers));
+ atomic_inc(&eb->spinning_writers);
+ /* atomic_dec_and_test implies a barrier */
+ if (atomic_dec_and_test(&eb->blocking_writers))
+ cond_wake_up_nomb(&eb->write_lock_wq);
}
/*
@@ -232,16 +237,9 @@ again:
wait_event(eb->read_lock_wq, atomic_read(&eb->blocking_readers) == 0);
wait_event(eb->write_lock_wq, atomic_read(&eb->blocking_writers) == 0);
write_lock(&eb->lock);
- if (atomic_read(&eb->blocking_readers)) {
+ if (atomic_read(&eb->blocking_readers) ||
+ atomic_read(&eb->blocking_writers)) {
write_unlock(&eb->lock);
- wait_event(eb->read_lock_wq,
- atomic_read(&eb->blocking_readers) == 0);
- goto again;
- }
- if (atomic_read(&eb->blocking_writers)) {
- write_unlock(&eb->lock);
- wait_event(eb->write_lock_wq,
- atomic_read(&eb->blocking_writers) == 0);
goto again;
}
WARN_ON(atomic_read(&eb->spinning_writers));