diff options
Diffstat (limited to 'fs/btrfs/locking.c')
-rw-r--r-- | fs/btrfs/locking.c | 47 |
1 files changed, 25 insertions, 22 deletions
diff --git a/fs/btrfs/locking.c b/fs/btrfs/locking.c index 7201d000f61d..7f89ca6f1fbc 100644 --- a/fs/btrfs/locking.c +++ b/fs/btrfs/locking.c @@ -48,11 +48,24 @@ void btrfs_set_lock_blocking_write(struct extent_buffer *eb) } } -/* - * 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 @@ -62,23 +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); } /* |