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

[Tsutomu Itoh <t-itoh@jp.fujitsu.com>]

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

> +}
> +
>  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