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>
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