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// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (c) 2015, Primary Data, Inc. All rights reserved.
*
* Tao Peng <bergwolf@primarydata.com>
*/
#include <linux/dcache.h>
#include <linux/exportfs.h>
#include <linux/nfs.h>
#include <linux/nfs_fs.h>
#include "internal.h"
#include "nfstrace.h"
#define NFSDBG_FACILITY NFSDBG_VFS
enum {
FILEID_HIGH_OFF = 0, /* inode fileid high */
FILEID_LOW_OFF, /* inode fileid low */
FILE_I_TYPE_OFF, /* inode type */
EMBED_FH_OFF /* embeded server fh */
};
static struct nfs_fh *nfs_exp_embedfh(__u32 *p)
{
return (struct nfs_fh *)(p + EMBED_FH_OFF);
}
/*
* Let's break subtree checking for now... otherwise we'll have to embed parent fh
* but there might not be enough space.
*/
static int
nfs_encode_fh(struct inode *inode, __u32 *p, int *max_len, struct inode *parent)
{
struct nfs_fh *server_fh = NFS_FH(inode);
struct nfs_fh *clnt_fh = nfs_exp_embedfh(p);
size_t fh_size = offsetof(struct nfs_fh, data) + server_fh->size;
int len = EMBED_FH_OFF + XDR_QUADLEN(fh_size);
dprintk("%s: max fh len %d inode %p parent %p",
__func__, *max_len, inode, parent);
if (*max_len < len || IS_AUTOMOUNT(inode)) {
dprintk("%s: fh len %d too small, required %d\n",
__func__, *max_len, len);
*max_len = len;
return FILEID_INVALID;
}
p[FILEID_HIGH_OFF] = NFS_FILEID(inode) >> 32;
p[FILEID_LOW_OFF] = NFS_FILEID(inode);
p[FILE_I_TYPE_OFF] = inode->i_mode & S_IFMT;
p[len - 1] = 0; /* Padding */
nfs_copy_fh(clnt_fh, server_fh);
*max_len = len;
dprintk("%s: result fh fileid %llu mode %u size %d\n",
__func__, NFS_FILEID(inode), inode->i_mode, *max_len);
return *max_len;
}
static struct dentry *
nfs_fh_to_dentry(struct super_block *sb, struct fid *fid,
int fh_len, int fh_type)
{
struct nfs4_label *label = NULL;
struct nfs_fattr *fattr = NULL;
struct nfs_fh *server_fh = nfs_exp_embedfh(fid->raw);
size_t fh_size = offsetof(struct nfs_fh, data) + server_fh->size;
const struct nfs_rpc_ops *rpc_ops;
struct dentry *dentry;
struct inode *inode;
int len = EMBED_FH_OFF + XDR_QUADLEN(fh_size);
u32 *p = fid->raw;
int ret;
/* NULL translates to ESTALE */
if (fh_len < len || fh_type != len)
return NULL;
fattr = nfs_alloc_fattr();
if (fattr == NULL) {
dentry = ERR_PTR(-ENOMEM);
goto out;
}
fattr->fileid = ((u64)p[FILEID_HIGH_OFF] << 32) + p[FILEID_LOW_OFF];
fattr->mode = p[FILE_I_TYPE_OFF];
fattr->valid |= NFS_ATTR_FATTR_FILEID | NFS_ATTR_FATTR_TYPE;
dprintk("%s: fileid %llu mode %d\n", __func__, fattr->fileid, fattr->mode);
inode = nfs_ilookup(sb, fattr, server_fh);
if (inode)
goto out_found;
label = nfs4_label_alloc(NFS_SB(sb), GFP_KERNEL);
if (IS_ERR(label)) {
dentry = ERR_CAST(label);
goto out_free_fattr;
}
rpc_ops = NFS_SB(sb)->nfs_client->rpc_ops;
ret = rpc_ops->getattr(NFS_SB(sb), server_fh, fattr, label, NULL);
if (ret) {
dprintk("%s: getattr failed %d\n", __func__, ret);
trace_nfs_fh_to_dentry(sb, server_fh, fattr->fileid, ret);
dentry = ERR_PTR(ret);
goto out_free_label;
}
inode = nfs_fhget(sb, server_fh, fattr, label);
out_found:
dentry = d_obtain_alias(inode);
out_free_label:
nfs4_label_free(label);
out_free_fattr:
nfs_free_fattr(fattr);
out:
return dentry;
}
static struct dentry *
nfs_get_parent(struct dentry *dentry)
{
int ret;
struct inode *inode = d_inode(dentry), *pinode;
struct super_block *sb = inode->i_sb;
struct nfs_server *server = NFS_SB(sb);
struct nfs_fattr *fattr = NULL;
struct nfs4_label *label = NULL;
struct dentry *parent;
struct nfs_rpc_ops const *ops = server->nfs_client->rpc_ops;
struct nfs_fh fh;
if (!ops->lookupp)
return ERR_PTR(-EACCES);
fattr = nfs_alloc_fattr();
if (fattr == NULL) {
parent = ERR_PTR(-ENOMEM);
goto out;
}
label = nfs4_label_alloc(server, GFP_KERNEL);
if (IS_ERR(label)) {
parent = ERR_CAST(label);
goto out_free_fattr;
}
ret = ops->lookupp(inode, &fh, fattr, label);
if (ret) {
parent = ERR_PTR(ret);
goto out_free_label;
}
pinode = nfs_fhget(sb, &fh, fattr, label);
parent = d_obtain_alias(pinode);
out_free_label:
nfs4_label_free(label);
out_free_fattr:
nfs_free_fattr(fattr);
out:
return parent;
}
const struct export_operations nfs_export_ops = {
.encode_fh = nfs_encode_fh,
.fh_to_dentry = nfs_fh_to_dentry,
.get_parent = nfs_get_parent,
.flags = EXPORT_OP_NOWCC|EXPORT_OP_NOSUBTREECHK|
EXPORT_OP_CLOSE_BEFORE_UNLINK|EXPORT_OP_REMOTE_FS|
EXPORT_OP_NOATOMIC_ATTR,
};
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