Re: [Ocfs2-devel] [PATCH v1 5/5] ocfs2: rewrite error handling of ocfs2_fill_super - Joseph Qi via Ocfs2-devel

From: Joseph Qi via Ocfs2-devel <ocfs2-devel@oss.oracle.com>
To: Heming Zhao <heming.zhao@suse.com>, ocfs2-devel@oss.oracle.com
Subject: Re: [Ocfs2-devel] [PATCH v1 5/5] ocfs2: rewrite error handling of ocfs2_fill_super
Date: Sat, 9 Apr 2022 22:02:16 +0800	[thread overview]
Message-ID: <c917d4bf-3405-08b5-41a3-60579733fde1@linux.alibaba.com> (raw)
In-Reply-To: <20220408103012.1419-6-heming.zhao@suse.com>

On 4/8/22 6:30 PM, Heming Zhao wrote:
> current ocfs2_fill_super error handling is very simple, and includes
> kernel crash possibility.
> 
> e.g.
> 
> ocfs2_fill_super
>   ocfs2_initialize_super // fails in check max_slots & return
> 
> Then osb->osb_mount_event is not properly initialized, and then will
> crash at wake_up(&osb->osb_mount_event) in goto label read_super_error.
> 
With patch 3, this case won't exist any more.

> For fixing the issue and enhancing error handling, we rewrite error
> handling of ocfs2_fill_super.
> 
> Signed-off-by: Heming Zhao <heming.zhao@suse.com>
> ---
>  fs/ocfs2/super.c | 67 ++++++++++++++++++++++++------------------------
>  1 file changed, 33 insertions(+), 34 deletions(-)
> 
> diff --git a/fs/ocfs2/super.c b/fs/ocfs2/super.c
> index d4b7a29cb364..c3efd9ad49ac 100644
> --- a/fs/ocfs2/super.c
> +++ b/fs/ocfs2/super.c
> @@ -989,28 +989,27 @@ static int ocfs2_fill_super(struct super_block *sb, void *data, int silent)
>  
>  	if (!ocfs2_parse_options(sb, data, &parsed_options, 0)) {
>  		status = -EINVAL;
> -		goto read_super_error;
> +		goto out;
>  	}
>  
>  	/* probe for superblock */
>  	status = ocfs2_sb_probe(sb, &bh, &sector_size, &stats);
>  	if (status < 0) {
>  		mlog(ML_ERROR, "superblock probe failed!\n");
> -		goto read_super_error;
> +		goto out;
>  	}
>  
>  	status = ocfs2_initialize_super(sb, bh, sector_size, &stats);
> -	osb = OCFS2_SB(sb);
> -	if (status < 0) {
> -		mlog_errno(status);
> -		goto read_super_error;
> -	}
>  	brelse(bh);
>  	bh = NULL;
> +	if (status < 0)
> +		goto out;
> +
> +	osb = OCFS2_SB(sb);
>  
>  	if (!ocfs2_check_set_options(sb, &parsed_options)) {
>  		status = -EINVAL;
> -		goto read_super_error;
> +		goto out_super;
>  	}
>  	osb->s_mount_opt = parsed_options.mount_opt;
>  	osb->s_atime_quantum = parsed_options.atime_quantum;
> @@ -1027,7 +1026,7 @@ static int ocfs2_fill_super(struct super_block *sb, void *data, int silent)
>  
>  	status = ocfs2_verify_userspace_stack(osb, &parsed_options);
>  	if (status)
> -		goto read_super_error;
> +		goto out_super;
>  
>  	sb->s_magic = OCFS2_SUPER_MAGIC;
>  
> @@ -1041,7 +1040,7 @@ static int ocfs2_fill_super(struct super_block *sb, void *data, int silent)
>  			status = -EACCES;
>  			mlog(ML_ERROR, "Readonly device detected but readonly "
>  			     "mount was not specified.\n");
> -			goto read_super_error;
> +			goto out_super;
>  		}
>  
>  		/* You should not be able to start a local heartbeat
> @@ -1050,7 +1049,7 @@ static int ocfs2_fill_super(struct super_block *sb, void *data, int silent)
>  			status = -EROFS;
>  			mlog(ML_ERROR, "Local heartbeat specified on readonly "
>  			     "device.\n");
> -			goto read_super_error;
> +			goto out_super;
>  		}
>  
>  		status = ocfs2_check_journals_nolocks(osb);
> @@ -1059,9 +1058,7 @@ static int ocfs2_fill_super(struct super_block *sb, void *data, int silent)
>  				mlog(ML_ERROR, "Recovery required on readonly "
>  				     "file system, but write access is "
>  				     "unavailable.\n");
> -			else
> -				mlog_errno(status);
> -			goto read_super_error;
> +			goto out_super;
>  		}
>  
>  		ocfs2_set_ro_flag(osb, 1);
> @@ -1077,10 +1074,8 @@ static int ocfs2_fill_super(struct super_block *sb, void *data, int silent)
>  	}
>  
>  	status = ocfs2_verify_heartbeat(osb);
> -	if (status < 0) {
> -		mlog_errno(status);
> -		goto read_super_error;
> -	}
> +	if (status < 0)
> +		goto out_super;
>  
>  	osb->osb_debug_root = debugfs_create_dir(osb->uuid_str,
>  						 ocfs2_debugfs_root);
> @@ -1094,15 +1089,14 @@ static int ocfs2_fill_super(struct super_block *sb, void *data, int silent)
>  
>  	status = ocfs2_mount_volume(sb);
>  	if (status < 0)
> -		goto read_super_error;
> +		goto out_debugfs;
>  
>  	if (osb->root_inode)
>  		inode = igrab(osb->root_inode);
>  
>  	if (!inode) {
>  		status = -EIO;
> -		mlog_errno(status);
> -		goto read_super_error;
> +		goto out_journal;
>  	}
>  
>  	osb->osb_dev_kset = kset_create_and_add(sb->s_id, NULL,
> @@ -1110,7 +1104,7 @@ static int ocfs2_fill_super(struct super_block *sb, void *data, int silent)
>  	if (!osb->osb_dev_kset) {
>  		status = -ENOMEM;
>  		mlog(ML_ERROR, "Unable to create device kset %s.\n", sb->s_id);
> -		goto read_super_error;
> +		goto out_journal;
>  	}
>  
>  	/* Create filecheck sysfs related directories/files at
> @@ -1119,14 +1113,13 @@ static int ocfs2_fill_super(struct super_block *sb, void *data, int silent)
>  		status = -ENOMEM;
>  		mlog(ML_ERROR, "Unable to create filecheck sysfs directory at "
>  			"/sys/fs/ocfs2/%s/filecheck.\n", sb->s_id);
> -		goto read_super_error;
> +		goto out_journal;
>  	}
>  
>  	root = d_make_root(inode);
>  	if (!root) {
>  		status = -ENOMEM;
> -		mlog_errno(status);
> -		goto read_super_error;
> +		goto out_journal;
>  	}
>  
>  	sb->s_root = root;
> @@ -1178,17 +1171,23 @@ static int ocfs2_fill_super(struct super_block *sb, void *data, int silent)
>  
>  	return status;
>  
> -read_super_error:
> -	brelse(bh);
> +out_journal:

rename it to out_dismount?

> +	mlog_errno(status);
> +	atomic_set(&osb->vol_state, VOLUME_DISABLED);
> +	wake_up(&osb->osb_mount_event);
> +	ocfs2_dismount_volume(sb, 1);
>  
> -	if (status)
> -		mlog_errno(status);
> +	return status;

Or remove mlog_errno() before and then just goto out?

>  
> -	if (osb) {
> -		atomic_set(&osb->vol_state, VOLUME_DISABLED);
> -		wake_up(&osb->osb_mount_event);
> -		ocfs2_dismount_volume(sb, 1);
> -	}
> +out_debugfs:
> +	debugfs_remove_recursive(osb->osb_debug_root);
> +out_super:
> +	ocfs2_release_system_inodes(osb);
> +	kfree(osb->recovery_map);
> +	ocfs2_delete_osb(osb);
> +	kfree(osb);

Seems we have to take care all resources in ocfs2_initialize_super()?

> +out:
> +	mlog_errno(status);
>  
As I described in your previous mail, ocfs2_sb_probe() may return error
with non-NULL bh, so we should brelse here.

Thanks,
Joseph

>  	return status;
>  }

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