btrfs: Streamline replace sem unlock in btrfs_dev_replace_start

[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 ee0989c7e3a9ca3a78465be5ec6780a046c6e322..94f000b0ca792c7dcf28044683f49df060054f52 100644 (file)
--- a/fs/btrfs/dev-replace.c
+++ b/fs/btrfs/dev-replace.c
@@ -201,7 +201,7 @@ static int btrfs_init_dev_replace_tgtdev(struct btrfs_fs_info *fs_info,
                return PTR_ERR(bdev);
        }
 
-       filemap_write_and_wait(bdev->bd_inode->i_mapping);
+       sync_blockdev(bdev);
 
        devices = &fs_info->fs_devices->devices;
        list_for_each_entry(device, devices, dev_list) {
@@ -237,7 +237,6 @@ static int btrfs_init_dev_replace_tgtdev(struct btrfs_fs_info *fs_info,
        }
        rcu_assign_pointer(device->name, name);
 
-       mutex_lock(&fs_info->fs_devices->device_list_mutex);
        set_bit(BTRFS_DEV_STATE_WRITEABLE, &device->dev_state);
        device->generation = 0;
        device->io_width = fs_info->sectorsize;
@@ -256,6 +255,8 @@ static int btrfs_init_dev_replace_tgtdev(struct btrfs_fs_info *fs_info,
        device->dev_stats_valid = 1;
        set_blocksize(device->bdev, BTRFS_BDEV_BLOCKSIZE);
        device->fs_devices = fs_info->fs_devices;
+
+       mutex_lock(&fs_info->fs_devices->device_list_mutex);
        list_add(&device->dev_list, &fs_info->fs_devices->devices);
        fs_info->fs_devices->num_devices++;
        fs_info->fs_devices->open_devices++;
@@ -399,7 +400,6 @@ static int btrfs_dev_replace_start(struct btrfs_fs_info *fs_info,
        int ret;
        struct btrfs_device *tgt_device = NULL;
        struct btrfs_device *src_device = NULL;
-       bool need_unlock;
 
        src_device = btrfs_find_device_by_devspec(fs_info, srcdevid,
                                                  srcdev_name);
@@ -413,11 +413,6 @@ static int btrfs_dev_replace_start(struct btrfs_fs_info *fs_info,
                return -ETXTBSY;
        }
 
-       ret = btrfs_init_dev_replace_tgtdev(fs_info, tgtdev_name,
-                                           src_device, &tgt_device);
-       if (ret)
-               return ret;
-
        /*
         * Here we commit the transaction to make sure commit_total_bytes
         * of all the devices are updated.
@@ -431,7 +426,11 @@ static int btrfs_dev_replace_start(struct btrfs_fs_info *fs_info,
                return PTR_ERR(trans);
        }
 
-       need_unlock = true;
+       ret = btrfs_init_dev_replace_tgtdev(fs_info, tgtdev_name,
+                                           src_device, &tgt_device);
+       if (ret)
+               return ret;
+
        down_write(&dev_replace->rwsem);
        switch (dev_replace->replace_state) {
        case BTRFS_IOCTL_DEV_REPLACE_STATE_NEVER_STARTED:
@@ -442,11 +441,11 @@ static int btrfs_dev_replace_start(struct btrfs_fs_info *fs_info,
        case BTRFS_IOCTL_DEV_REPLACE_STATE_SUSPENDED:
                ASSERT(0);
                ret = BTRFS_IOCTL_DEV_REPLACE_RESULT_ALREADY_STARTED;
+               up_write(&dev_replace->rwsem);
                goto leave;
        }
 
        dev_replace->cont_reading_from_srcdev_mode = read_src;
-       WARN_ON(!src_device);
        dev_replace->srcdev = src_device;
        dev_replace->tgtdev = tgt_device;
 
@@ -471,7 +470,6 @@ static int btrfs_dev_replace_start(struct btrfs_fs_info *fs_info,
        atomic64_set(&dev_replace->num_write_errors, 0);
        atomic64_set(&dev_replace->num_uncorrectable_read_errors, 0);
        up_write(&dev_replace->rwsem);
-       need_unlock = false;
 
        ret = btrfs_sysfs_add_device_link(tgt_device->fs_devices, tgt_device);
        if (ret)
@@ -483,12 +481,12 @@ static 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);
-               need_unlock = true;
                down_write(&dev_replace->rwsem);
                dev_replace->replace_state =
                        BTRFS_IOCTL_DEV_REPLACE_STATE_NEVER_STARTED;
                dev_replace->srcdev = NULL;
                dev_replace->tgtdev = NULL;
+               up_write(&dev_replace->rwsem);
                goto leave;
        }
 
@@ -510,8 +508,6 @@ static int btrfs_dev_replace_start(struct btrfs_fs_info *fs_info,
        return ret;
 
 leave:
-       if (need_unlock)
-               up_write(&dev_replace->rwsem);
        btrfs_destroy_dev_replace_tgtdev(tgt_device);
        return ret;
 }