exportfs: be careful to only return expected errors.

When nfsd calls fh_to_dentry, it expect ESTALE or ENOMEM as errors.
In particular it can be tempting to return ENOENT, but this is not
handled well by nfsd.

Rather than requiring strict adherence to error code code filesystems,
treat all unexpected error codes the same as ESTALE.  This is safest.

Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
This commit is contained in:
NeilBrown 2016-08-04 10:19:06 +10:00 committed by J. Bruce Fields
parent 7d22fc11c7
commit 09bb8bfffd
2 changed files with 13 additions and 10 deletions

View file

@ -428,10 +428,10 @@ struct dentry *exportfs_decode_fh(struct vfsmount *mnt, struct fid *fid,
if (!nop || !nop->fh_to_dentry)
return ERR_PTR(-ESTALE);
result = nop->fh_to_dentry(mnt->mnt_sb, fid, fh_len, fileid_type);
if (!result)
result = ERR_PTR(-ESTALE);
if (IS_ERR(result))
return result;
if (PTR_ERR(result) == -ENOMEM)
return ERR_CAST(result);
if (IS_ERR_OR_NULL(result))
return ERR_PTR(-ESTALE);
if (d_is_dir(result)) {
/*
@ -541,6 +541,8 @@ struct dentry *exportfs_decode_fh(struct vfsmount *mnt, struct fid *fid,
err_result:
dput(result);
if (err != -ENOMEM)
err = -ESTALE;
return ERR_PTR(err);
}
EXPORT_SYMBOL_GPL(exportfs_decode_fh);