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