Re: [PATCH] nilfs2: add more check routines in mount process

[Ryusuke Konishi <ryusuke-sG5X7nlA6pw@public.gmane.org>]

On Wed, 12 Aug 2009 14:17:59 +0800, Zhu Yanhai wrote:
> nilfs2: Add more safeguard routines and protections in mount process,
> which also makes nilsf2 report consistency error messages when checkpoint
> number is invalid.
> 
> Signed-off-by: Zhu Yanhai <zhu.yanhai-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
> ---
>  fs/nilfs2/cpfile.c |   11 ++++++++---
>  fs/nilfs2/super.c  |    7 ++++++-
>  2 files changed, 14 insertions(+), 4 deletions(-)
> 
> diff --git a/fs/nilfs2/cpfile.c b/fs/nilfs2/cpfile.c
> index aec942c..1c6cfb5 100644
> --- a/fs/nilfs2/cpfile.c
> +++ b/fs/nilfs2/cpfile.c
> @@ -815,8 +815,10 @@ int nilfs_cpfile_is_snapshot(struct inode *cpfile, __u64 cno)
>  	void *kaddr;
>  	int ret;
>  
> -	if (cno == 0)
> -		return -ENOENT; /* checkpoint number 0 is invalid */
> +	/* CP number is invalid if it's zero or larger than the
> +	largest	exist one.*/
> +	if (cno == 0 || cno >= nilfs_mdt_cno(cpfile))
> +		return -ENOENT;
>  	down_read(&NILFS_MDT(cpfile)->mi_sem);
>  
>  	ret = nilfs_cpfile_get_checkpoint_block(cpfile, cno, 0, &bh);
> @@ -824,7 +826,10 @@ int nilfs_cpfile_is_snapshot(struct inode *cpfile, __u64 cno)
>  		goto out;
>  	kaddr = kmap_atomic(bh->b_page, KM_USER0);
>  	cp = nilfs_cpfile_block_get_checkpoint(cpfile, cno, bh, kaddr);
> -	ret = nilfs_checkpoint_snapshot(cp);
> +	if (nilfs_checkpoint_invalid(cp))
> +		ret = -ENOENT;
> +	else
> +		ret = nilfs_checkpoint_snapshot(cp);
>  	kunmap_atomic(kaddr, KM_USER0);
>  	brelse(bh);
>  
> diff --git a/fs/nilfs2/super.c b/fs/nilfs2/super.c
> index 8e2ec43..b2ad589 100644
> --- a/fs/nilfs2/super.c
> +++ b/fs/nilfs2/super.c
> @@ -814,10 +814,15 @@ nilfs_fill_super(struct super_block *sb, void *data, int silent,
>  
>  	if (sb->s_flags & MS_RDONLY) {
>  		if (nilfs_test_opt(sbi, SNAPSHOT)) {
> +			down_read(&nilfs->ns_segctor_sem);
>  			err = nilfs_cpfile_is_snapshot(nilfs->ns_cpfile,
>  						       sbi->s_snapshot_cno);
> -			if (err < 0)
> +			up_read(&nilfs->ns_segctor_sem);
> +			if (err < 0) {
> +				if (err == -ENOENT)
> +					err = -EINVAL;
>  				goto failed_sbi;
> +			}
>  			if (!err) {
>  				printk(KERN_ERR
>  				       "NILFS: The specified checkpoint is "
> -- 
> 1.6.2.2

Applied. Thank you!

Ryusuke Konishi