1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /* mountpoint management
4 * Copyright (C) 2002 Red Hat, Inc. All Rights Reserved.
5 * Written by David Howells (dhowells@redhat.com)
8 #include <linux/kernel.h>
9 #include <linux/module.h>
10 #include <linux/init.h>
12 #include <linux/pagemap.h>
13 #include <linux/mount.h>
14 #include <linux/namei.h>
15 #include <linux/gfp.h>
16 #include <linux/fs_context.h>
20 static struct dentry *afs_mntpt_lookup(struct inode *dir,
21 struct dentry *dentry,
23 static int afs_mntpt_open(struct inode *inode, struct file *file);
24 static void afs_mntpt_expiry_timed_out(struct work_struct *work);
26 const struct file_operations afs_mntpt_file_operations = {
27 .open = afs_mntpt_open,
28 .llseek = noop_llseek,
31 const struct inode_operations afs_mntpt_inode_operations = {
32 .lookup = afs_mntpt_lookup,
33 .readlink = page_readlink,
34 .getattr = afs_getattr,
35 .listxattr = afs_listxattr,
38 const struct inode_operations afs_autocell_inode_operations = {
39 .getattr = afs_getattr,
42 static LIST_HEAD(afs_vfsmounts);
43 static DECLARE_DELAYED_WORK(afs_mntpt_expiry_timer, afs_mntpt_expiry_timed_out);
45 static unsigned long afs_mntpt_expiry_timeout = 10 * 60;
47 static const char afs_root_volume[] = "root.cell";
50 * no valid lookup procedure on this sort of dir
52 static struct dentry *afs_mntpt_lookup(struct inode *dir,
53 struct dentry *dentry,
56 _enter("%p,%p{%pd2}", dir, dentry, dentry);
57 return ERR_PTR(-EREMOTE);
61 * no valid open procedure on this sort of dir
63 static int afs_mntpt_open(struct inode *inode, struct file *file)
65 _enter("%p,%p{%pD2}", inode, file, file);
70 * Set the parameters for the proposed superblock.
72 static int afs_mntpt_set_params(struct fs_context *fc, struct dentry *mntpt)
74 struct afs_fs_context *ctx = fc->fs_private;
75 struct afs_super_info *src_as = AFS_FS_S(mntpt->d_sb);
76 struct afs_vnode *vnode = AFS_FS_I(d_inode(mntpt));
77 struct afs_cell *cell;
81 if (fc->net_ns != src_as->net_ns) {
83 fc->net_ns = get_net(src_as->net_ns);
86 if (src_as->volume && src_as->volume->type == AFSVL_RWVOL) {
87 ctx->type = AFSVL_RWVOL;
91 afs_unuse_cell(ctx->net, ctx->cell, afs_cell_trace_unuse_mntpt);
94 if (test_bit(AFS_VNODE_PSEUDODIR, &vnode->flags)) {
95 /* if the directory is a pseudo directory, use the d_name */
96 unsigned size = mntpt->d_name.len;
101 p = mntpt->d_name.name;
102 if (mntpt->d_name.name[0] == '.') {
105 ctx->type = AFSVL_RWVOL;
108 if (size > AFS_MAXCELLNAME)
109 return -ENAMETOOLONG;
111 cell = afs_lookup_cell(ctx->net, p, size, NULL, false);
113 pr_err("kAFS: unable to lookup cell '%pd'\n", mntpt);
114 return PTR_ERR(cell);
118 ctx->volname = afs_root_volume;
119 ctx->volnamesz = sizeof(afs_root_volume) - 1;
121 /* read the contents of the AFS special symlink */
123 loff_t size = i_size_read(d_inode(mntpt));
127 ctx->cell = afs_use_cell(src_as->cell, afs_cell_trace_use_mntpt);
129 if (size < 2 || size > PAGE_SIZE - 1)
132 page = read_mapping_page(d_inode(mntpt)->i_mapping, 0, NULL);
134 return PTR_ERR(page);
136 if (PageError(page)) {
137 ret = afs_bad(AFS_FS_I(d_inode(mntpt)), afs_file_error_mntpt);
144 if (buf[size - 1] == '.')
145 ret = vfs_parse_fs_string(fc, "source", buf, size - 1);
156 * create a vfsmount to be automounted
158 static struct vfsmount *afs_mntpt_do_automount(struct dentry *mntpt)
160 struct fs_context *fc;
161 struct vfsmount *mnt;
164 BUG_ON(!d_inode(mntpt));
166 fc = fs_context_for_submount(&afs_fs_type, mntpt);
170 ret = afs_mntpt_set_params(fc, mntpt);
181 * handle an automount point
183 struct vfsmount *afs_d_automount(struct path *path)
185 struct vfsmount *newmnt;
187 _enter("{%pd}", path->dentry);
189 newmnt = afs_mntpt_do_automount(path->dentry);
193 mntget(newmnt); /* prevent immediate expiration */
194 mnt_set_expiry(newmnt, &afs_vfsmounts);
195 queue_delayed_work(afs_wq, &afs_mntpt_expiry_timer,
196 afs_mntpt_expiry_timeout * HZ);
197 _leave(" = %p", newmnt);
202 * handle mountpoint expiry timer going off
204 static void afs_mntpt_expiry_timed_out(struct work_struct *work)
208 if (!list_empty(&afs_vfsmounts)) {
209 mark_mounts_for_expiry(&afs_vfsmounts);
210 queue_delayed_work(afs_wq, &afs_mntpt_expiry_timer,
211 afs_mntpt_expiry_timeout * HZ);
218 * kill the AFS mountpoint timer if it's still running
220 void afs_mntpt_kill_timer(void)
224 ASSERT(list_empty(&afs_vfsmounts));
225 cancel_delayed_work_sync(&afs_mntpt_expiry_timer);