On Thu, Jan 05, 2017 at 03:24:14PM +0800, zhangyi (F) wrote:
>
> On 2017/1/5 7:35, Theodore Ts'o wrote:
> >
> > So how exactly how did we get into this state? When we read the inode
> > into memory, if i_nlink is zero, we declare the file system as
> > corrupted immediately.
> >
> > So I assume this is happening the on-disk i_links_count (which is read
> > into inode->i_nlink) was too low. So I think the way we should be
> > handling this is in unlink and rename, before we let i_nlink drop to
D'oh, /me failed to notice the patch was against fs/inode.c, not
fs/ext4/inode.c. Sorry for the noise.
> > zero, we need to check to see if there are other dcache entries
> > pointing at the inode. If so, we need to call ext4_error(), and in
> > the errors=continue case, return EFSCORRUPTED (aka EUCLEAN).
> >
>
> diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
> --- a/fs/ext4/namei.c
> +++ b/fs/ext4/namei.c
> @@ -3662,6 +3662,11 @@ static int ext4_rename(struct inode *old_dir, struct dentry *old_dentry,
> }
>
> if (new.inode) {
> + if (new.inode->i_nlink == 0) {
> + ext4_warning_inode(new.inode, "Removing file '%.*s' with no links",
> + new.dentry->d_name.len, new.dentry->d_name.name);
> + set_nlink(new.inode, 1);
Not sure we need to dump the dentry d_name, but I guess it can't hurt.
> + }
> ext4_dec_count(handle, new.inode);
> new.inode->i_ctime = ext4_current_time(new.inode);
> }
>
> Because the filesystem have many errors, and the reason of i_nlink becomes
> zero is unknown, the on-disk i_links_count was too low may be one reason. I
> think we can add i_nlink check in ext4_rename just like ext4_unlink did, it
> can avoid inversion under any case.
Er... yes, you could add the same hunk to ext4_unlink.
--D
>
>
>
>
>
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