^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1) // SPDX-License-Identifier: GPL-2.0-or-later
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2) /* getroot.c: get the root dentry for an NFS mount
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 4) * Copyright (C) 2006 Red Hat, Inc. All Rights Reserved.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 5) * Written by David Howells (dhowells@redhat.com)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 6) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 7)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 8) #include <linux/module.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 9) #include <linux/init.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 10)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 11) #include <linux/time.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 12) #include <linux/kernel.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 13) #include <linux/mm.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 14) #include <linux/string.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 15) #include <linux/stat.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 16) #include <linux/errno.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 17) #include <linux/unistd.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 18) #include <linux/sunrpc/clnt.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 19) #include <linux/sunrpc/stats.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 20) #include <linux/nfs_fs.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 21) #include <linux/nfs_mount.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 22) #include <linux/lockd/bind.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 23) #include <linux/seq_file.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 24) #include <linux/mount.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 25) #include <linux/vfs.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 26) #include <linux/namei.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 27) #include <linux/security.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 28)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 29) #include <linux/uaccess.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 30)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 31) #include "internal.h"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 32)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 33) #define NFSDBG_FACILITY NFSDBG_CLIENT
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 34)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 35) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 36) * Set the superblock root dentry.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 37) * Note that this function frees the inode in case of error.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 38) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 39) static int nfs_superblock_set_dummy_root(struct super_block *sb, struct inode *inode)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 40) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 41) /* The mntroot acts as the dummy root dentry for this superblock */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 42) if (sb->s_root == NULL) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 43) sb->s_root = d_make_root(inode);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 44) if (sb->s_root == NULL)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 45) return -ENOMEM;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 46) ihold(inode);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 47) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 48) * Ensure that this dentry is invisible to d_find_alias().
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 49) * Otherwise, it may be spliced into the tree by
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 50) * d_splice_alias if a parent directory from the same
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 51) * filesystem gets mounted at a later time.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 52) * This again causes shrink_dcache_for_umount_subtree() to
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 53) * Oops, since the test for IS_ROOT() will fail.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 54) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 55) spin_lock(&d_inode(sb->s_root)->i_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 56) spin_lock(&sb->s_root->d_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 57) hlist_del_init(&sb->s_root->d_u.d_alias);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 58) spin_unlock(&sb->s_root->d_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 59) spin_unlock(&d_inode(sb->s_root)->i_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 60) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 61) return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 62) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 63)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 64) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 65) * get an NFS2/NFS3 root dentry from the root filehandle
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 66) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 67) int nfs_get_root(struct super_block *s, struct fs_context *fc)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 68) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 69) struct nfs_fs_context *ctx = nfs_fc2context(fc);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 70) struct nfs_server *server = NFS_SB(s);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 71) struct nfs_fsinfo fsinfo;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 72) struct dentry *root;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 73) struct inode *inode;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 74) char *name;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 75) int error = -ENOMEM;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 76) unsigned long kflags = 0, kflags_out = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 77)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 78) name = kstrdup(fc->source, GFP_KERNEL);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 79) if (!name)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 80) goto out;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 81)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 82) /* get the actual root for this mount */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 83) fsinfo.fattr = nfs_alloc_fattr();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 84) if (fsinfo.fattr == NULL)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 85) goto out_name;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 86)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 87) fsinfo.fattr->label = nfs4_label_alloc(server, GFP_KERNEL);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 88) if (IS_ERR(fsinfo.fattr->label))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 89) goto out_fattr;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 90) error = server->nfs_client->rpc_ops->getroot(server, ctx->mntfh, &fsinfo);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 91) if (error < 0) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 92) dprintk("nfs_get_root: getattr error = %d\n", -error);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 93) nfs_errorf(fc, "NFS: Couldn't getattr on root");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 94) goto out_label;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 95) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 96)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 97) inode = nfs_fhget(s, ctx->mntfh, fsinfo.fattr, NULL);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 98) if (IS_ERR(inode)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 99) dprintk("nfs_get_root: get root inode failed\n");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 100) error = PTR_ERR(inode);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 101) nfs_errorf(fc, "NFS: Couldn't get root inode");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 102) goto out_label;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 103) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 104)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 105) error = nfs_superblock_set_dummy_root(s, inode);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 106) if (error != 0)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 107) goto out_label;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 108)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 109) /* root dentries normally start off anonymous and get spliced in later
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 110) * if the dentry tree reaches them; however if the dentry already
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 111) * exists, we'll pick it up at this point and use it as the root
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 112) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 113) root = d_obtain_root(inode);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 114) if (IS_ERR(root)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 115) dprintk("nfs_get_root: get root dentry failed\n");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 116) error = PTR_ERR(root);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 117) nfs_errorf(fc, "NFS: Couldn't get root dentry");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 118) goto out_label;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 119) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 120)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 121) security_d_instantiate(root, inode);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 122) spin_lock(&root->d_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 123) if (IS_ROOT(root) && !root->d_fsdata &&
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 124) !(root->d_flags & DCACHE_NFSFS_RENAMED)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 125) root->d_fsdata = name;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 126) name = NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 127) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 128) spin_unlock(&root->d_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 129) fc->root = root;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 130) if (NFS_SB(s)->caps & NFS_CAP_SECURITY_LABEL)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 131) kflags |= SECURITY_LSM_NATIVE_LABELS;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 132) if (ctx->clone_data.sb) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 133) if (d_inode(fc->root)->i_fop != &nfs_dir_operations) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 134) error = -ESTALE;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 135) goto error_splat_root;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 136) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 137) /* clone lsm security options from the parent to the new sb */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 138) error = security_sb_clone_mnt_opts(ctx->clone_data.sb,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 139) s, kflags, &kflags_out);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 140) } else {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 141) error = security_sb_set_mnt_opts(s, fc->security,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 142) kflags, &kflags_out);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 143) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 144) if (error)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 145) goto error_splat_root;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 146) if (NFS_SB(s)->caps & NFS_CAP_SECURITY_LABEL &&
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 147) !(kflags_out & SECURITY_LSM_NATIVE_LABELS))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 148) NFS_SB(s)->caps &= ~NFS_CAP_SECURITY_LABEL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 149)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 150) nfs_setsecurity(inode, fsinfo.fattr, fsinfo.fattr->label);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 151) error = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 152)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 153) out_label:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 154) nfs4_label_free(fsinfo.fattr->label);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 155) out_fattr:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 156) nfs_free_fattr(fsinfo.fattr);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 157) out_name:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 158) kfree(name);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 159) out:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 160) return error;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 161) error_splat_root:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 162) dput(fc->root);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 163) fc->root = NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 164) goto out_label;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 165) }
Orange Pi5 kernel
Deprecated Linux kernel 5.10.110 for OrangePi 5/5B/5+ boards
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