diff options
| -rw-r--r-- | fs/btrfs/locking.c | 10 |
1 files changed, 8 insertions, 2 deletions
diff --git a/fs/btrfs/locking.c b/fs/btrfs/locking.c index 47b0a88c12a..6d8db2f5c38 100644 --- a/fs/btrfs/locking.c +++ b/fs/btrfs/locking.c @@ -71,12 +71,13 @@ void btrfs_clear_lock_blocking(struct extent_buffer *eb) static int btrfs_spin_on_block(struct extent_buffer *eb) { int i; + for (i = 0; i < 512; i++) { - cpu_relax(); if (!test_bit(EXTENT_BUFFER_BLOCKING, &eb->bflags)) return 1; if (need_resched()) break; + cpu_relax(); } return 0; } @@ -102,6 +103,7 @@ int btrfs_try_spin_lock(struct extent_buffer *eb) /* spin for a bit on the BLOCKING flag */ for (i = 0; i < 2; i++) { + cpu_relax(); if (!btrfs_spin_on_block(eb)) break; @@ -148,6 +150,9 @@ int btrfs_tree_lock(struct extent_buffer *eb) DEFINE_WAIT(wait); wait.func = btrfs_wake_function; + if (!btrfs_spin_on_block(eb)) + goto sleep; + while(1) { spin_nested(eb); @@ -165,9 +170,10 @@ int btrfs_tree_lock(struct extent_buffer *eb) * spin for a bit, and if the blocking flag goes away, * loop around */ + cpu_relax(); if (btrfs_spin_on_block(eb)) continue; - +sleep: prepare_to_wait_exclusive(&eb->lock_wq, &wait, TASK_UNINTERRUPTIBLE); |