btrfs: split dev-replace locking helpers for read and write

[sfrench/cifs-2.6.git] / fs / btrfs / dev-replace.c

diff --git a/fs/btrfs/dev-replace.c b/fs/btrfs/dev-replace.c
index e279f04b338889361a11e5d26a06feea948ee13d..0d203633bb96493dbc8abda9bb4fe4bf9bb2f3cd 100644 (file)
--- a/fs/btrfs/dev-replace.c
+++ b/fs/btrfs/dev-replace.c
@@ -205,13 +205,13 @@ int btrfs_run_dev_replace(struct btrfs_trans_handle *trans,
        struct btrfs_dev_replace_item *ptr;
        struct btrfs_dev_replace *dev_replace = &fs_info->dev_replace;
 
-       btrfs_dev_replace_lock(dev_replace, 0);
+       btrfs_dev_replace_read_lock(dev_replace);
        if (!dev_replace->is_valid ||
            !dev_replace->item_needs_writeback) {
-               btrfs_dev_replace_unlock(dev_replace, 0);
+               btrfs_dev_replace_read_unlock(dev_replace);
                return 0;
        }
-       btrfs_dev_replace_unlock(dev_replace, 0);
+       btrfs_dev_replace_read_unlock(dev_replace);
 
        key.objectid = 0;
        key.type = BTRFS_DEV_REPLACE_KEY;
@@ -269,7 +269,7 @@ int btrfs_run_dev_replace(struct btrfs_trans_handle *trans,
        ptr = btrfs_item_ptr(eb, path->slots[0],
                             struct btrfs_dev_replace_item);
 
-       btrfs_dev_replace_lock(dev_replace, 1);
+       btrfs_dev_replace_write_lock(dev_replace);
        if (dev_replace->srcdev)
                btrfs_set_dev_replace_src_devid(eb, ptr,
                        dev_replace->srcdev->devid);
@@ -292,7 +292,7 @@ int btrfs_run_dev_replace(struct btrfs_trans_handle *trans,
        btrfs_set_dev_replace_cursor_right(eb, ptr,
                dev_replace->cursor_right);
        dev_replace->item_needs_writeback = 0;
-       btrfs_dev_replace_unlock(dev_replace, 1);
+       btrfs_dev_replace_write_unlock(dev_replace);
 
        btrfs_mark_buffer_dirty(eb);
 
@@ -357,7 +357,7 @@ int btrfs_dev_replace_start(struct btrfs_fs_info *fs_info,
                return PTR_ERR(trans);
        }
 
-       btrfs_dev_replace_lock(dev_replace, 1);
+       btrfs_dev_replace_write_lock(dev_replace);
        switch (dev_replace->replace_state) {
        case BTRFS_IOCTL_DEV_REPLACE_STATE_NEVER_STARTED:
        case BTRFS_IOCTL_DEV_REPLACE_STATE_FINISHED:
@@ -395,7 +395,7 @@ int btrfs_dev_replace_start(struct btrfs_fs_info *fs_info,
        dev_replace->item_needs_writeback = 1;
        atomic64_set(&dev_replace->num_write_errors, 0);
        atomic64_set(&dev_replace->num_uncorrectable_read_errors, 0);
-       btrfs_dev_replace_unlock(dev_replace, 1);
+       btrfs_dev_replace_write_unlock(dev_replace);
 
        ret = btrfs_sysfs_add_device_link(tgt_device->fs_devices, tgt_device);
        if (ret)
@@ -407,7 +407,7 @@ int btrfs_dev_replace_start(struct btrfs_fs_info *fs_info,
        trans = btrfs_start_transaction(root, 0);
        if (IS_ERR(trans)) {
                ret = PTR_ERR(trans);
-               btrfs_dev_replace_lock(dev_replace, 1);
+               btrfs_dev_replace_write_lock(dev_replace);
                goto leave;
        }
 
@@ -431,7 +431,7 @@ int btrfs_dev_replace_start(struct btrfs_fs_info *fs_info,
 leave:
        dev_replace->srcdev = NULL;
        dev_replace->tgtdev = NULL;
-       btrfs_dev_replace_unlock(dev_replace, 1);
+       btrfs_dev_replace_write_unlock(dev_replace);
        btrfs_destroy_dev_replace_tgtdev(fs_info, tgt_device);
        return ret;
 }
@@ -498,18 +498,18 @@ static int btrfs_dev_replace_finishing(struct btrfs_fs_info *fs_info,
        /* don't allow cancel or unmount to disturb the finishing procedure */
        mutex_lock(&dev_replace->lock_finishing_cancel_unmount);
 
-       btrfs_dev_replace_lock(dev_replace, 0);
+       btrfs_dev_replace_read_lock(dev_replace);
        /* was the operation canceled, or is it finished? */
        if (dev_replace->replace_state !=
            BTRFS_IOCTL_DEV_REPLACE_STATE_STARTED) {
-               btrfs_dev_replace_unlock(dev_replace, 0);
+               btrfs_dev_replace_read_unlock(dev_replace);
                mutex_unlock(&dev_replace->lock_finishing_cancel_unmount);
                return 0;
        }
 
        tgt_device = dev_replace->tgtdev;
        src_device = dev_replace->srcdev;
-       btrfs_dev_replace_unlock(dev_replace, 0);
+       btrfs_dev_replace_read_unlock(dev_replace);
 
        /*
         * flush all outstanding I/O and inode extent mappings before the
@@ -534,7 +534,7 @@ static int btrfs_dev_replace_finishing(struct btrfs_fs_info *fs_info,
        /* keep away write_all_supers() during the finishing procedure */
        mutex_lock(&fs_info->fs_devices->device_list_mutex);
        mutex_lock(&fs_info->chunk_mutex);
-       btrfs_dev_replace_lock(dev_replace, 1);
+       btrfs_dev_replace_write_lock(dev_replace);
        dev_replace->replace_state =
                scrub_ret ? BTRFS_IOCTL_DEV_REPLACE_STATE_CANCELED
                          : BTRFS_IOCTL_DEV_REPLACE_STATE_FINISHED;
@@ -554,7 +554,7 @@ static int btrfs_dev_replace_finishing(struct btrfs_fs_info *fs_info,
                                 btrfs_dev_name(src_device),
                                 src_device->devid,
                                 rcu_str_deref(tgt_device->name), scrub_ret);
-               btrfs_dev_replace_unlock(dev_replace, 1);
+               btrfs_dev_replace_write_unlock(dev_replace);
                mutex_unlock(&fs_info->chunk_mutex);
                mutex_unlock(&fs_info->fs_devices->device_list_mutex);
                mutex_unlock(&uuid_mutex);
@@ -591,7 +591,7 @@ static int btrfs_dev_replace_finishing(struct btrfs_fs_info *fs_info,
        list_add(&tgt_device->dev_alloc_list, &fs_info->fs_devices->alloc_list);
        fs_info->fs_devices->rw_devices++;
 
-       btrfs_dev_replace_unlock(dev_replace, 1);
+       btrfs_dev_replace_write_unlock(dev_replace);
 
        btrfs_rm_dev_replace_blocked(fs_info);
 
@@ -684,7 +684,7 @@ void btrfs_dev_replace_status(struct btrfs_fs_info *fs_info,
 {
        struct btrfs_dev_replace *dev_replace = &fs_info->dev_replace;
 
-       btrfs_dev_replace_lock(dev_replace, 0);
+       btrfs_dev_replace_read_lock(dev_replace);
        /* even if !dev_replace_is_valid, the values are good enough for
         * the replace_status ioctl */
        args->result = BTRFS_IOCTL_DEV_REPLACE_RESULT_NO_ERROR;
@@ -696,7 +696,7 @@ void btrfs_dev_replace_status(struct btrfs_fs_info *fs_info,
        args->status.num_uncorrectable_read_errors =
                atomic64_read(&dev_replace->num_uncorrectable_read_errors);
        args->status.progress_1000 = btrfs_dev_replace_progress(fs_info);
-       btrfs_dev_replace_unlock(dev_replace, 0);
+       btrfs_dev_replace_read_unlock(dev_replace);
 }
 
 int btrfs_dev_replace_cancel(struct btrfs_fs_info *fs_info)
@@ -713,13 +713,13 @@ int btrfs_dev_replace_cancel(struct btrfs_fs_info *fs_info)
                return -EROFS;
 
        mutex_lock(&dev_replace->lock_finishing_cancel_unmount);
-       btrfs_dev_replace_lock(dev_replace, 1);
+       btrfs_dev_replace_write_lock(dev_replace);
        switch (dev_replace->replace_state) {
        case BTRFS_IOCTL_DEV_REPLACE_STATE_NEVER_STARTED:
        case BTRFS_IOCTL_DEV_REPLACE_STATE_FINISHED:
        case BTRFS_IOCTL_DEV_REPLACE_STATE_CANCELED:
                result = BTRFS_IOCTL_DEV_REPLACE_RESULT_NOT_STARTED;
-               btrfs_dev_replace_unlock(dev_replace, 1);
+               btrfs_dev_replace_write_unlock(dev_replace);
                goto leave;
        case BTRFS_IOCTL_DEV_REPLACE_STATE_STARTED:
        case BTRFS_IOCTL_DEV_REPLACE_STATE_SUSPENDED:
@@ -733,7 +733,7 @@ int btrfs_dev_replace_cancel(struct btrfs_fs_info *fs_info)
        dev_replace->replace_state = BTRFS_IOCTL_DEV_REPLACE_STATE_CANCELED;
        dev_replace->time_stopped = get_seconds();
        dev_replace->item_needs_writeback = 1;
-       btrfs_dev_replace_unlock(dev_replace, 1);
+       btrfs_dev_replace_write_unlock(dev_replace);
        btrfs_scrub_cancel(fs_info);
 
        trans = btrfs_start_transaction(root, 0);
@@ -762,7 +762,7 @@ void btrfs_dev_replace_suspend_for_unmount(struct btrfs_fs_info *fs_info)
        struct btrfs_dev_replace *dev_replace = &fs_info->dev_replace;
 
        mutex_lock(&dev_replace->lock_finishing_cancel_unmount);
-       btrfs_dev_replace_lock(dev_replace, 1);
+       btrfs_dev_replace_write_lock(dev_replace);
        switch (dev_replace->replace_state) {
        case BTRFS_IOCTL_DEV_REPLACE_STATE_NEVER_STARTED:
        case BTRFS_IOCTL_DEV_REPLACE_STATE_FINISHED:
@@ -778,7 +778,7 @@ void btrfs_dev_replace_suspend_for_unmount(struct btrfs_fs_info *fs_info)
                break;
        }
 
-       btrfs_dev_replace_unlock(dev_replace, 1);
+       btrfs_dev_replace_write_unlock(dev_replace);
        mutex_unlock(&dev_replace->lock_finishing_cancel_unmount);
 }
 
@@ -788,12 +788,12 @@ int btrfs_resume_dev_replace_async(struct btrfs_fs_info *fs_info)
        struct task_struct *task;
        struct btrfs_dev_replace *dev_replace = &fs_info->dev_replace;
 
-       btrfs_dev_replace_lock(dev_replace, 1);
+       btrfs_dev_replace_write_lock(dev_replace);
        switch (dev_replace->replace_state) {
        case BTRFS_IOCTL_DEV_REPLACE_STATE_NEVER_STARTED:
        case BTRFS_IOCTL_DEV_REPLACE_STATE_FINISHED:
        case BTRFS_IOCTL_DEV_REPLACE_STATE_CANCELED:
-               btrfs_dev_replace_unlock(dev_replace, 1);
+               btrfs_dev_replace_write_unlock(dev_replace);
                return 0;
        case BTRFS_IOCTL_DEV_REPLACE_STATE_STARTED:
                break;
@@ -807,10 +807,10 @@ int btrfs_resume_dev_replace_async(struct btrfs_fs_info *fs_info)
                           "cannot continue dev_replace, tgtdev is missing");
                btrfs_info(fs_info,
                           "you may cancel the operation after 'mount -o degraded'");
-               btrfs_dev_replace_unlock(dev_replace, 1);
+               btrfs_dev_replace_write_unlock(dev_replace);
                return 0;
        }
-       btrfs_dev_replace_unlock(dev_replace, 1);
+       btrfs_dev_replace_write_unlock(dev_replace);
 
        WARN_ON(test_and_set_bit(BTRFS_FS_EXCL_OP, &fs_info->flags));
        task = kthread_run(btrfs_dev_replace_kthread, fs_info, "btrfs-devrepl");
@@ -879,37 +879,37 @@ int btrfs_dev_replace_is_ongoing(struct btrfs_dev_replace *dev_replace)
        return 1;
 }
 
-void btrfs_dev_replace_lock(struct btrfs_dev_replace *dev_replace, int rw)
+void btrfs_dev_replace_read_lock(struct btrfs_dev_replace *dev_replace)
 {
-       if (rw == 1) {
-               /* write */
-again:
-               wait_event(dev_replace->read_lock_wq,
-                          atomic_read(&dev_replace->blocking_readers) == 0);
-               write_lock(&dev_replace->lock);
-               if (atomic_read(&dev_replace->blocking_readers)) {
-                       write_unlock(&dev_replace->lock);
-                       goto again;
-               }
-       } else {
-               read_lock(&dev_replace->lock);
-               atomic_inc(&dev_replace->read_locks);
-       }
+       read_lock(&dev_replace->lock);
+       atomic_inc(&dev_replace->read_locks);
 }
 
-void btrfs_dev_replace_unlock(struct btrfs_dev_replace *dev_replace, int rw)
+void btrfs_dev_replace_read_unlock(struct btrfs_dev_replace *dev_replace)
 {
-       if (rw == 1) {
-               /* write */
-               ASSERT(atomic_read(&dev_replace->blocking_readers) == 0);
+       ASSERT(atomic_read(&dev_replace->read_locks) > 0);
+       atomic_dec(&dev_replace->read_locks);
+       read_unlock(&dev_replace->lock);
+}
+
+void btrfs_dev_replace_write_lock(struct btrfs_dev_replace *dev_replace)
+{
+again:
+       wait_event(dev_replace->read_lock_wq,
+                  atomic_read(&dev_replace->blocking_readers) == 0);
+       write_lock(&dev_replace->lock);
+       if (atomic_read(&dev_replace->blocking_readers)) {
                write_unlock(&dev_replace->lock);
-       } else {
-               ASSERT(atomic_read(&dev_replace->read_locks) > 0);
-               atomic_dec(&dev_replace->read_locks);
-               read_unlock(&dev_replace->lock);
+               goto again;
        }
 }
 
+void btrfs_dev_replace_write_unlock(struct btrfs_dev_replace *dev_replace)
+{
+       ASSERT(atomic_read(&dev_replace->blocking_readers) == 0);
+       write_unlock(&dev_replace->lock);
+}
+
 /* inc blocking cnt and release read lock */
 void btrfs_dev_replace_set_lock_blocking(
                                        struct btrfs_dev_replace *dev_replace)