Re: [RFC PATCH 4/4 v2] Btrfs: deal with filesystem state at mount, umount

[liubo <liubo2009@cn.fujitsu.com>]

On 12/02/2010 10:29 AM, Tsutomu Itoh wrote:
> Hi,
> 
> I found 1 typo.
> 
> (2010/12/01 19:21), liubo wrote:
>> Since there is a filesystem state, we should deal with it carefully at mount,
>>  umount and remount.
>>
>> - At mount, the FS state should be checked if there is error on these FS.
>>   If it does have, btrfsck is recommended.
>> - At umount, the FS state should be saved into disk for consistency.
>>
>> Signed-off-by: Liu Bo <liubo2009@cn.fujitsu.com>
>> ---
>>  fs/btrfs/disk-io.c |   47 ++++++++++++++++++++++++++++++++++++++++++++++-
>>  1 files changed, 46 insertions(+), 1 deletions(-)
>>
>> diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
>> index b40dfe4..663d360 100644
>> --- a/fs/btrfs/disk-io.c
>> +++ b/fs/btrfs/disk-io.c
>> @@ -43,6 +43,8 @@
>>  static struct extent_io_ops btree_extent_io_ops;
>>  static void end_workqueue_fn(struct btrfs_work *work);
>>  static void free_fs_root(struct btrfs_root *root);
>> +static void btrfs_check_super_valid(struct btrfs_fs_info *fs_info,
>> +				     int read_only);
>>  
>>  /*
>>   * end_io_wq structs are used to do processing in task context when an IO is
>> @@ -1700,6 +1702,11 @@ struct btrfs_root *open_ctree(struct super_block *sb,
>>  	if (!btrfs_super_root(disk_super))
>>  		goto fail_iput;
>>  
>> +	/* check filesystem state */
>> +	fs_info->fs_state |= btrfs_super_flags(disk_super);
>> +
>> +	btrfs_check_super_valid(fs_info, sb->s_flags & MS_RDONLY);
>> +
>>  	ret = btrfs_parse_options(tree_root, options);
>>  	if (ret) {
>>  		err = ret;
>> @@ -2405,10 +2412,17 @@ int btrfs_commit_super(struct btrfs_root *root)
>>  	up_write(&root->fs_info->cleanup_work_sem);
>>  
>>  	trans = btrfs_join_transaction(root, 1);
>> +	if (IS_ERR(trans))
>> +		return PTR_ERR(trans);
>> +
>>  	ret = btrfs_commit_transaction(trans, root);
>>  	BUG_ON(ret);
>> +
>>  	/* run commit again to drop the original snapshot */
>>  	trans = btrfs_join_transaction(root, 1);
>> +	if (IS_ERR(trans))
>> +		return PTR_ERR(trans);
>> +
>>  	btrfs_commit_transaction(trans, root);
>>  	ret = btrfs_write_and_wait_transaction(NULL, root);
>>  	BUG_ON(ret);
>> @@ -2426,8 +2440,28 @@ int close_ctree(struct btrfs_root *root)
>>  	smp_mb();
>>  
>>  	btrfs_put_block_group_cache(fs_info);
>> +
>> +	/*
>> +	 * Here come 2 situations when btrfs flips readonly:
>> +	 *
>> +	 * 1. when btrfs flips readonly somewhere else before
>> +	 * btrfs_commit_super, sb->s_flags has MS_RDONLY flag,
>> +	 * and btrfs will skip to write sb directly to keep
>> +	 * ERROR state on disk.
>> +	 *
>> +	 * 2. when btrfs flips readonly just in btrfs_commit_super,
>> +	 * and in such case, btrfs cannnot write sb via btrfs_commit_super,
>> +	 * and since fs_state has been set BTRFS_SUPER_FLAG_ERROR flag,
>> +	 * btrfs will directly write sb.
>> +	 */
>>  	if (!(fs_info->sb->s_flags & MS_RDONLY)) {
>> -		ret =  btrfs_commit_super(root);
>> +		ret = btrfs_commit_super(root);
>> +		if (ret)
>> +			printk(KERN_ERR "btrfs: commit super ret %d\n", ret);
>> +	}
>> +
>> +	if (fs_info->fs_state & BTRFS_SUPER_FLAG_ERROR) {
>> +		ret = write_ctree_super(NULL, root, 0);
>>  		if (ret)
>>  			printk(KERN_ERR "btrfs: commit super ret %d\n", ret);
>>  	}
>> @@ -2603,6 +2637,17 @@ out:
>>  	return 0;
>>  }
>>  
>> +static void btrfs_check_super_valid(struct btrfs_fs_info *fs_info,
>> +			      int read_only)
>> +{
>> +	if (read_only)
>> +		return;
>> +
>> +	if (fs_info->fs_state & BTRFS_SUPER_FLAG_ERROR)
>> +		printk(KERN_WARNING "warning: mount fs with errors, "
>> +		       "running btfsck is recommended\n");
> 
> btfsck -> btrfsck

ahh, my fault, sorry for my carelessness.

Thanks a lot for reviewing.

thanks,
Liu Bo

> 
>> +}
>> +
>>  static struct extent_io_ops btree_extent_io_ops = {
>>  	.write_cache_pages_lock_hook = btree_lock_page_hook,
>>  	.readpage_end_io_hook = btree_readpage_end_io_hook,
> 
> Regards,
> Itoh
> 
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