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	btrfs: do not background blkdev_put()
At the end of unmount/dev-delete, if the device exclusive open is not
actually closed, then there might be a race with another program in
the userland who is trying to open the device in exclusive mode and
it may fail for eg:
      unmount /btrfs; fsck /dev/x
      btrfs dev del /dev/x /btrfs; fsck /dev/x
so here background blkdev_put() is not a choice
Signed-off-by: Anand Jain <Anand.Jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Chris Mason <clm@fb.com>
			
			
This commit is contained in:
		
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						1423881941
					
				
					 1 changed files with 19 additions and 8 deletions
				
			
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					@ -834,10 +834,6 @@ static void __free_device(struct work_struct *work)
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	struct btrfs_device *device;
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						struct btrfs_device *device;
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	device = container_of(work, struct btrfs_device, rcu_work);
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						device = container_of(work, struct btrfs_device, rcu_work);
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	if (device->bdev)
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		blkdev_put(device->bdev, device->mode);
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	rcu_string_free(device->name);
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						rcu_string_free(device->name);
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	kfree(device);
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						kfree(device);
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}
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					}
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					@ -852,6 +848,17 @@ static void free_device(struct rcu_head *head)
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	schedule_work(&device->rcu_work);
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						schedule_work(&device->rcu_work);
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}
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					}
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					static void btrfs_close_bdev(struct btrfs_device *device)
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					{
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						if (device->bdev && device->writeable) {
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							sync_blockdev(device->bdev);
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							invalidate_bdev(device->bdev);
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						}
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						if (device->bdev)
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							blkdev_put(device->bdev, device->mode);
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					}
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static void btrfs_close_one_device(struct btrfs_device *device)
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					static void btrfs_close_one_device(struct btrfs_device *device)
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{
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					{
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	struct btrfs_fs_devices *fs_devices = device->fs_devices;
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						struct btrfs_fs_devices *fs_devices = device->fs_devices;
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					@ -870,10 +877,7 @@ static void btrfs_close_one_device(struct btrfs_device *device)
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	if (device->missing)
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						if (device->missing)
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		fs_devices->missing_devices--;
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							fs_devices->missing_devices--;
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	if (device->bdev && device->writeable) {
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						btrfs_close_bdev(device);
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		sync_blockdev(device->bdev);
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		invalidate_bdev(device->bdev);
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	}
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	new_device = btrfs_alloc_device(NULL, &device->devid,
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						new_device = btrfs_alloc_device(NULL, &device->devid,
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					device->uuid);
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										device->uuid);
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					@ -1932,6 +1936,8 @@ int btrfs_rm_device(struct btrfs_root *root, char *device_path, u64 devid)
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		btrfs_sysfs_rm_device_link(root->fs_info->fs_devices, device);
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							btrfs_sysfs_rm_device_link(root->fs_info->fs_devices, device);
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	}
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						}
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						btrfs_close_bdev(device);
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	call_rcu(&device->rcu, free_device);
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						call_rcu(&device->rcu, free_device);
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	num_devices = btrfs_super_num_devices(root->fs_info->super_copy) - 1;
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						num_devices = btrfs_super_num_devices(root->fs_info->super_copy) - 1;
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					@ -2025,6 +2031,9 @@ void btrfs_rm_dev_replace_free_srcdev(struct btrfs_fs_info *fs_info,
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		/* zero out the old super if it is writable */
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							/* zero out the old super if it is writable */
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		btrfs_scratch_superblocks(srcdev->bdev, srcdev->name->str);
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							btrfs_scratch_superblocks(srcdev->bdev, srcdev->name->str);
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	}
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						}
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						btrfs_close_bdev(srcdev);
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	call_rcu(&srcdev->rcu, free_device);
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						call_rcu(&srcdev->rcu, free_device);
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	/*
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						/*
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					@ -2080,6 +2089,8 @@ void btrfs_destroy_dev_replace_tgtdev(struct btrfs_fs_info *fs_info,
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	 * the device_list_mutex lock.
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						 * the device_list_mutex lock.
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	 */
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						 */
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	btrfs_scratch_superblocks(tgtdev->bdev, tgtdev->name->str);
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						btrfs_scratch_superblocks(tgtdev->bdev, tgtdev->name->str);
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						btrfs_close_bdev(tgtdev);
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	call_rcu(&tgtdev->rcu, free_device);
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						call_rcu(&tgtdev->rcu, free_device);
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}
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					}
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