btrfs: make use of btrfs_find_device_by_user_input()

btrfs_rm_device() has a section of the code which can be replaced
btrfs_find_device_by_user_input()

Signed-off-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index ab28d9d..40bbe0a 100644 (file)
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -1752,13 +1752,11 @@ int btrfs_rm_device(struct btrfs_root *root, char *device_path)
 {
        struct btrfs_device *device;
        struct btrfs_device *next_device;
-       struct block_device *bdev;
+       struct block_device *bdev = NULL;
        struct buffer_head *bh = NULL;
-       struct btrfs_super_block *disk_super;
+       struct btrfs_super_block *disk_super = NULL;
        struct btrfs_fs_devices *cur_devices;
-       u64 devid;
        u64 num_devices;
-       u8 *dev_uuid;
        int ret = 0;
        bool clear_super = false;
 
@@ -1768,57 +1766,19 @@ int btrfs_rm_device(struct btrfs_root *root, char *device_path)
        if (ret)
                goto out;
 
-       if (strcmp(device_path, "missing") == 0) {
-               struct list_head *devices;
-               struct btrfs_device *tmp;
-
-               device = NULL;
-               devices = &root->fs_info->fs_devices->devices;
-               /*
-                * It is safe to read the devices since the volume_mutex
-                * is held.
-                */
-               list_for_each_entry(tmp, devices, dev_list) {
-                       if (tmp->in_fs_metadata &&
-                           !tmp->is_tgtdev_for_dev_replace &&
-                           !tmp->bdev) {
-                               device = tmp;
-                               break;
-                       }
-               }
-               bdev = NULL;
-               bh = NULL;
-               disk_super = NULL;
-               if (!device) {
-                       ret = BTRFS_ERROR_DEV_MISSING_NOT_FOUND;
-                       goto out;
-               }
-       } else {
-               ret = btrfs_get_bdev_and_sb(device_path,
-                                           FMODE_WRITE | FMODE_EXCL,
-                                           root->fs_info->bdev_holder, 0,
-                                           &bdev, &bh);
-               if (ret)
-                       goto out;
-               disk_super = (struct btrfs_super_block *)bh->b_data;
-               devid = btrfs_stack_device_id(&disk_super->dev_item);
-               dev_uuid = disk_super->dev_item.uuid;
-               device = btrfs_find_device(root->fs_info, devid, dev_uuid,
-                                          disk_super->fsid);
-               if (!device) {
-                       ret = -ENOENT;
-                       goto error_brelse;
-               }
-       }
+       ret = btrfs_find_device_by_user_input(root, 0, device_path,
+                               &device);
+       if (ret)
+               goto out;
 
        if (device->is_tgtdev_for_dev_replace) {
                ret = BTRFS_ERROR_DEV_TGT_REPLACE;
-               goto error_brelse;
+               goto out;
        }
 
        if (device->writeable && root->fs_info->fs_devices->rw_devices == 1) {
                ret = BTRFS_ERROR_DEV_ONLY_WRITABLE;
-               goto error_brelse;
+               goto out;
        }
 
        if (device->writeable) {
@@ -1908,16 +1868,33 @@ int btrfs_rm_device(struct btrfs_root *root, char *device_path)
         * at this point, the device is zero sized.  We want to
         * remove it from the devices list and zero out the old super
         */
-       if (clear_super && disk_super) {
+       if (clear_super) {
                u64 bytenr;
                int i;
 
+               if (!disk_super) {
+                       ret = btrfs_get_bdev_and_sb(device_path,
+                                       FMODE_WRITE | FMODE_EXCL,
+                                       root->fs_info->bdev_holder, 0,
+                                       &bdev, &bh);
+                       if (ret) {
+                               /*
+                                * It could be a failed device ok for clear_super
+                                * to fail. So return success
+                                */
+                               ret = 0;
+                               goto out;
+                       }
+
+                       disk_super = (struct btrfs_super_block *)bh->b_data;
+               }
                /* make sure this device isn't detected as part of
                 * the FS anymore
                 */
                memset(&disk_super->magic, 0, sizeof(disk_super->magic));
                set_buffer_dirty(bh);
                sync_dirty_buffer(bh);
+               brelse(bh);
 
                /* clear the mirror copies of super block on the disk
                 * being removed, 0th copy is been taken care above and
@@ -1929,7 +1906,6 @@ int btrfs_rm_device(struct btrfs_root *root, char *device_path)
                                        i_size_read(bdev->bd_inode))
                                break;
 
-                       brelse(bh);
                        bh = __bread(bdev, bytenr / 4096,
                                        BTRFS_SUPER_INFO_SIZE);
                        if (!bh)
@@ -1939,32 +1915,30 @@ int btrfs_rm_device(struct btrfs_root *root, char *device_path)
 
                        if (btrfs_super_bytenr(disk_super) != bytenr ||
                                btrfs_super_magic(disk_super) != BTRFS_MAGIC) {
+                               brelse(bh);
                                continue;
                        }
                        memset(&disk_super->magic, 0,
                                                sizeof(disk_super->magic));
                        set_buffer_dirty(bh);
                        sync_dirty_buffer(bh);
+                       brelse(bh);
                }
-       }
 
-       ret = 0;
-
-       if (bdev) {
-               /* Notify udev that device has changed */
-               btrfs_kobject_uevent(bdev, KOBJ_CHANGE);
+               if (bdev) {
+                       /* Notify udev that device has changed */
+                       btrfs_kobject_uevent(bdev, KOBJ_CHANGE);
 
-               /* Update ctime/mtime for device path for libblkid */
-               update_dev_time(device_path);
+                       /* Update ctime/mtime for device path for libblkid */
+                       update_dev_time(device_path);
+                       blkdev_put(bdev, FMODE_READ | FMODE_EXCL);
+               }
        }
 
-error_brelse:
-       brelse(bh);
-       if (bdev)
-               blkdev_put(bdev, FMODE_READ | FMODE_EXCL);
 out:
        mutex_unlock(&uuid_mutex);
        return ret;
+
 error_undo:
        if (device->writeable) {
                lock_chunks(root);
@@ -1973,7 +1947,7 @@ error_undo:
                device->fs_devices->rw_devices++;
                unlock_chunks(root);
        }
-       goto error_brelse;
+       goto out;
 }
 
 void btrfs_rm_dev_replace_remove_srcdev(struct btrfs_fs_info *fs_info,