Re: [PATCH v2] NFS: nfs_rename() handle -ERESTARTSYS dentry left behind

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On Wed, 2017-02-01 at 00:00 -0500, Benjamin Coddington wrote:
> An interrupted rename will leave the old dentry behind if the rename
> succeeds.  Fix this by moving the final local work of the rename to
> rpc_call_done so that the results of the RENAME can always be handled,
> even if the original process has already returned with -ERESTARTSYS.
> 
> Signed-off-by: Benjamin Coddington <bcodding@xxxxxxxxxx>
> ---
>  fs/nfs/dir.c | 36 +++++++++++++++++++++++++-----------
>  1 file changed, 25 insertions(+), 11 deletions(-)
> 
> diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
> index fad81041f5ab..fb499a3f21b5 100644
> --- a/fs/nfs/dir.c
> +++ b/fs/nfs/dir.c
> @@ -2002,6 +2002,29 @@ nfs_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry)
>  }
>  EXPORT_SYMBOL_GPL(nfs_link);
>  
> +static void
> +nfs_complete_rename(struct rpc_task *task, struct nfs_renamedata *data)
> +{
> +	struct dentry *old_dentry = data->old_dentry;
> +	struct dentry *new_dentry = data->new_dentry;
> +	struct inode *old_inode = d_inode(old_dentry);
> +	struct inode *new_inode = d_inode(new_dentry);
> +
> +	nfs_mark_for_revalidate(old_inode);
> +
> +	switch (task->tk_status) {
> +	case 0:
> +		if (new_inode != NULL)
> +			nfs_drop_nlink(new_inode);
> +		d_move(old_dentry, new_dentry);
> +		nfs_set_verifier(new_dentry,
> +					nfs_save_change_attribute(data->new_dir));
> +		break;
> +	case -ENOENT:
> +		nfs_dentry_handle_enoent(old_dentry);
> +	}
> +}
> +
>  /*
>   * RENAME
>   * FIXME: Some nfsds, like the Linux user space nfsd, may generate a
> @@ -2084,7 +2107,8 @@ int nfs_rename(struct inode *old_dir, struct dentry *old_dentry,
>  	if (new_inode != NULL)
>  		NFS_PROTO(new_inode)->return_delegation(new_inode);
>  
> -	task = nfs_async_rename(old_dir, new_dir, old_dentry, new_dentry, NULL);
> +	task = nfs_async_rename(old_dir, new_dir, old_dentry, new_dentry,
> +					nfs_complete_rename);
>  	if (IS_ERR(task)) {
>  		error = PTR_ERR(task);
>  		goto out;
> @@ -2094,21 +2118,11 @@ int nfs_rename(struct inode *old_dir, struct dentry *old_dentry,
>  	if (error == 0)
>  		error = task->tk_status;
>  	rpc_put_task(task);
> -	nfs_mark_for_revalidate(old_inode);
>  out:
>  	if (rehash)
>  		d_rehash(rehash);
>  	trace_nfs_rename_exit(old_dir, old_dentry,
>  			new_dir, new_dentry, error);
> -	if (!error) {
> -		if (new_inode != NULL)
> -			nfs_drop_nlink(new_inode);
> -		d_move(old_dentry, new_dentry);
> -		nfs_set_verifier(new_dentry,
> -					nfs_save_change_attribute(new_dir));
> -	} else if (error == -ENOENT)
> -		nfs_dentry_handle_enoent(old_dentry);
> -
>  	/* new dentry created? */
>  	if (dentry)
>  		dput(dentry);

Oof. I believe this patch is wrong and likely causing dcache
corruption.. If the task catches a signal here then you'll be doing the
d_move without holding the i_rwsem, and that isn't safe.

I think we need to go ahead and revert this immediately from mainline
and v4.11-stable, and do what we discussed with the v1 patch -- have the
rename completion function detect whether the original process has been
killed and mark the parents for revalidation if they were.

Thoughts?
-- 
Jeff Layton <jlayton@xxxxxxxxxx>
--
To unsubscribe from this list: send the line "unsubscribe linux-nfs" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html



[Index of Archives]     [Linux Filesystem Development]     [Linux USB Development]     [Linux Media Development]     [Video for Linux]     [Linux NILFS]     [Linux Audio Users]     [Yosemite Info]     [Linux SCSI]

  Powered by Linux