1 // SPDX-License-Identifier: GPL-2.0-or-later <<
2 /* getroot.c: get the root dentry for an NFS m 1 /* getroot.c: get the root dentry for an NFS mount
3 * 2 *
4 * Copyright (C) 2006 Red Hat, Inc. All Rights 3 * Copyright (C) 2006 Red Hat, Inc. All Rights Reserved.
5 * Written by David Howells (dhowells@redhat.c 4 * Written by David Howells (dhowells@redhat.com)
>> 5 *
>> 6 * This program is free software; you can redistribute it and/or
>> 7 * modify it under the terms of the GNU General Public License
>> 8 * as published by the Free Software Foundation; either version
>> 9 * 2 of the License, or (at your option) any later version.
6 */ 10 */
7 11
8 #include <linux/module.h> 12 #include <linux/module.h>
9 #include <linux/init.h> 13 #include <linux/init.h>
10 14
11 #include <linux/time.h> 15 #include <linux/time.h>
12 #include <linux/kernel.h> 16 #include <linux/kernel.h>
13 #include <linux/mm.h> 17 #include <linux/mm.h>
14 #include <linux/string.h> 18 #include <linux/string.h>
15 #include <linux/stat.h> 19 #include <linux/stat.h>
16 #include <linux/errno.h> 20 #include <linux/errno.h>
17 #include <linux/unistd.h> 21 #include <linux/unistd.h>
18 #include <linux/sunrpc/clnt.h> 22 #include <linux/sunrpc/clnt.h>
19 #include <linux/sunrpc/stats.h> 23 #include <linux/sunrpc/stats.h>
20 #include <linux/nfs_fs.h> 24 #include <linux/nfs_fs.h>
21 #include <linux/nfs_mount.h> 25 #include <linux/nfs_mount.h>
22 #include <linux/lockd/bind.h> 26 #include <linux/lockd/bind.h>
23 #include <linux/seq_file.h> 27 #include <linux/seq_file.h>
24 #include <linux/mount.h> 28 #include <linux/mount.h>
25 #include <linux/vfs.h> 29 #include <linux/vfs.h>
26 #include <linux/namei.h> 30 #include <linux/namei.h>
27 #include <linux/security.h> 31 #include <linux/security.h>
28 32
29 #include <linux/uaccess.h> 33 #include <linux/uaccess.h>
30 34
31 #include "internal.h" 35 #include "internal.h"
32 36
33 #define NFSDBG_FACILITY NFSDBG_CLIENT 37 #define NFSDBG_FACILITY NFSDBG_CLIENT
34 38
35 /* 39 /*
36 * Set the superblock root dentry. 40 * Set the superblock root dentry.
37 * Note that this function frees the inode in 41 * Note that this function frees the inode in case of error.
38 */ 42 */
39 static int nfs_superblock_set_dummy_root(struc 43 static int nfs_superblock_set_dummy_root(struct super_block *sb, struct inode *inode)
40 { 44 {
41 /* The mntroot acts as the dummy root 45 /* The mntroot acts as the dummy root dentry for this superblock */
42 if (sb->s_root == NULL) { 46 if (sb->s_root == NULL) {
43 sb->s_root = d_make_root(inode 47 sb->s_root = d_make_root(inode);
44 if (sb->s_root == NULL) 48 if (sb->s_root == NULL)
45 return -ENOMEM; 49 return -ENOMEM;
46 ihold(inode); 50 ihold(inode);
47 /* 51 /*
48 * Ensure that this dentry is 52 * Ensure that this dentry is invisible to d_find_alias().
49 * Otherwise, it may be splice 53 * Otherwise, it may be spliced into the tree by
50 * d_splice_alias if a parent 54 * d_splice_alias if a parent directory from the same
51 * filesystem gets mounted at 55 * filesystem gets mounted at a later time.
52 * This again causes shrink_dc 56 * This again causes shrink_dcache_for_umount_subtree() to
53 * Oops, since the test for IS 57 * Oops, since the test for IS_ROOT() will fail.
54 */ 58 */
55 spin_lock(&d_inode(sb->s_root) 59 spin_lock(&d_inode(sb->s_root)->i_lock);
56 spin_lock(&sb->s_root->d_lock) 60 spin_lock(&sb->s_root->d_lock);
57 hlist_del_init(&sb->s_root->d_ 61 hlist_del_init(&sb->s_root->d_u.d_alias);
58 spin_unlock(&sb->s_root->d_loc 62 spin_unlock(&sb->s_root->d_lock);
59 spin_unlock(&d_inode(sb->s_roo 63 spin_unlock(&d_inode(sb->s_root)->i_lock);
60 } 64 }
61 return 0; 65 return 0;
62 } 66 }
63 67
64 /* 68 /*
65 * get an NFS2/NFS3 root dentry from the root 69 * get an NFS2/NFS3 root dentry from the root filehandle
66 */ 70 */
67 int nfs_get_root(struct super_block *s, struct !! 71 struct dentry *nfs_get_root(struct super_block *sb, struct nfs_fh *mntfh,
>> 72 const char *devname)
68 { 73 {
69 struct nfs_fs_context *ctx = nfs_fc2co !! 74 struct nfs_server *server = NFS_SB(sb);
70 struct nfs_server *server = NFS_SB(s), <<
71 struct nfs_fsinfo fsinfo; 75 struct nfs_fsinfo fsinfo;
72 struct dentry *root; !! 76 struct dentry *ret;
73 struct inode *inode; 77 struct inode *inode;
74 char *name; !! 78 void *name = kstrdup(devname, GFP_KERNEL);
75 int error = -ENOMEM; !! 79 int error;
76 unsigned long kflags = 0, kflags_out = <<
77 80
78 name = kstrdup(fc->source, GFP_KERNEL) <<
79 if (!name) 81 if (!name)
80 goto out; !! 82 return ERR_PTR(-ENOMEM);
81 83
82 /* get the actual root for this mount 84 /* get the actual root for this mount */
83 fsinfo.fattr = nfs_alloc_fattr_with_la !! 85 fsinfo.fattr = nfs_alloc_fattr();
84 if (fsinfo.fattr == NULL) !! 86 if (fsinfo.fattr == NULL) {
85 goto out_name; !! 87 kfree(name);
>> 88 return ERR_PTR(-ENOMEM);
>> 89 }
86 90
87 error = server->nfs_client->rpc_ops->g !! 91 error = server->nfs_client->rpc_ops->getroot(server, mntfh, &fsinfo);
88 if (error < 0) { 92 if (error < 0) {
89 dprintk("nfs_get_root: getattr 93 dprintk("nfs_get_root: getattr error = %d\n", -error);
90 nfs_errorf(fc, "NFS: Couldn't !! 94 ret = ERR_PTR(error);
91 goto out_fattr; !! 95 goto out;
92 } 96 }
93 97
94 inode = nfs_fhget(s, ctx->mntfh, fsinf !! 98 inode = nfs_fhget(sb, mntfh, fsinfo.fattr, NULL);
95 if (IS_ERR(inode)) { 99 if (IS_ERR(inode)) {
96 dprintk("nfs_get_root: get roo 100 dprintk("nfs_get_root: get root inode failed\n");
97 error = PTR_ERR(inode); !! 101 ret = ERR_CAST(inode);
98 nfs_errorf(fc, "NFS: Couldn't !! 102 goto out;
99 goto out_fattr; <<
100 } 103 }
101 104
102 error = nfs_superblock_set_dummy_root( !! 105 error = nfs_superblock_set_dummy_root(sb, inode);
103 if (error != 0) !! 106 if (error != 0) {
104 goto out_fattr; !! 107 ret = ERR_PTR(error);
>> 108 goto out;
>> 109 }
105 110
106 /* root dentries normally start off an 111 /* root dentries normally start off anonymous and get spliced in later
107 * if the dentry tree reaches them; ho 112 * if the dentry tree reaches them; however if the dentry already
108 * exists, we'll pick it up at this po 113 * exists, we'll pick it up at this point and use it as the root
109 */ 114 */
110 root = d_obtain_root(inode); !! 115 ret = d_obtain_root(inode);
111 if (IS_ERR(root)) { !! 116 if (IS_ERR(ret)) {
112 dprintk("nfs_get_root: get roo 117 dprintk("nfs_get_root: get root dentry failed\n");
113 error = PTR_ERR(root); !! 118 goto out;
114 nfs_errorf(fc, "NFS: Couldn't <<
115 goto out_fattr; <<
116 } 119 }
117 120
118 security_d_instantiate(root, inode); !! 121 security_d_instantiate(ret, inode);
119 spin_lock(&root->d_lock); !! 122 spin_lock(&ret->d_lock);
120 if (IS_ROOT(root) && !root->d_fsdata & !! 123 if (IS_ROOT(ret) && !ret->d_fsdata &&
121 !(root->d_flags & DCACHE_NFSFS_REN !! 124 !(ret->d_flags & DCACHE_NFSFS_RENAMED)) {
122 root->d_fsdata = name; !! 125 ret->d_fsdata = name;
123 name = NULL; 126 name = NULL;
124 } 127 }
125 spin_unlock(&root->d_lock); !! 128 spin_unlock(&ret->d_lock);
126 fc->root = root; <<
127 if (server->caps & NFS_CAP_SECURITY_LA <<
128 kflags |= SECURITY_LSM_NATIVE_ <<
129 if (ctx->clone_data.sb) { <<
130 if (d_inode(fc->root)->i_fop ! <<
131 error = -ESTALE; <<
132 goto error_splat_root; <<
133 } <<
134 /* clone lsm security options <<
135 error = security_sb_clone_mnt_ <<
136 <<
137 if (error) <<
138 goto error_splat_root; <<
139 clone_server = NFS_SB(ctx->clo <<
140 server->has_sec_mnt_opts = clo <<
141 } else { <<
142 error = security_sb_set_mnt_op <<
143 <<
144 } <<
145 if (error) <<
146 goto error_splat_root; <<
147 if (server->caps & NFS_CAP_SECURITY_LA <<
148 !(kflags_out & SECURITY_LSM_NA <<
149 server->caps &= ~NFS_CAP_SECUR <<
150 <<
151 nfs_setsecurity(inode, fsinfo.fattr); <<
152 error = 0; <<
153 <<
154 out_fattr: <<
155 nfs_free_fattr(fsinfo.fattr); <<
156 out_name: <<
157 kfree(name); <<
158 out: 129 out:
159 return error; !! 130 kfree(name);
160 error_splat_root: !! 131 nfs_free_fattr(fsinfo.fattr);
161 dput(fc->root); !! 132 return ret;
162 fc->root = NULL; <<
163 goto out_fattr; <<
164 } 133 }
165 134
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