--- /dev/null
+/* mountpoint management
+ *
+ * Copyright (C) 2002 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/fs.h>
+#include <linux/pagemap.h>
+#include <linux/mount.h>
+#include <linux/namei.h>
+#include <linux/gfp.h>
+#include "internal.h"
+
+
+static struct dentry *afs_mntpt_lookup(struct inode *dir,
+ struct dentry *dentry,
+ unsigned int flags);
+static int afs_mntpt_open(struct inode *inode, struct file *file);
+static void afs_mntpt_expiry_timed_out(struct work_struct *work);
+
+const struct file_operations afs_mntpt_file_operations = {
+ .open = afs_mntpt_open,
+ .llseek = noop_llseek,
+};
+
+const struct inode_operations afs_mntpt_inode_operations = {
+ .lookup = afs_mntpt_lookup,
+ .readlink = page_readlink,
+ .getattr = afs_getattr,
+};
+
+const struct inode_operations afs_autocell_inode_operations = {
+ .getattr = afs_getattr,
+};
+
+static LIST_HEAD(afs_vfsmounts);
+static DECLARE_DELAYED_WORK(afs_mntpt_expiry_timer, afs_mntpt_expiry_timed_out);
+
+static unsigned long afs_mntpt_expiry_timeout = 10 * 60;
+
+/*
+ * check a symbolic link to see whether it actually encodes a mountpoint
+ * - sets the AFS_VNODE_MOUNTPOINT flag on the vnode appropriately
+ */
+int afs_mntpt_check_symlink(struct afs_vnode *vnode, struct key *key)
+{
+ struct page *page;
+ size_t size;
+ char *buf;
+ int ret;
+
+ _enter("{%x:%u,%u}",
+ vnode->fid.vid, vnode->fid.vnode, vnode->fid.unique);
+
+ /* read the contents of the symlink into the pagecache */
+ page = read_cache_page(AFS_VNODE_TO_I(vnode)->i_mapping, 0,
+ afs_page_filler, key);
+ if (IS_ERR(page)) {
+ ret = PTR_ERR(page);
+ goto out;
+ }
+
+ ret = -EIO;
+ if (PageError(page))
+ goto out_free;
+
+ buf = kmap(page);
+
+ /* examine the symlink's contents */
+ size = vnode->status.size;
+ _debug("symlink to %*.*s", (int) size, (int) size, buf);
+
+ if (size > 2 &&
+ (buf[0] == '%' || buf[0] == '#') &&
+ buf[size - 1] == '.'
+ ) {
+ _debug("symlink is a mountpoint");
+ spin_lock(&vnode->lock);
+ set_bit(AFS_VNODE_MOUNTPOINT, &vnode->flags);
+ vnode->vfs_inode.i_flags |= S_AUTOMOUNT;
+ spin_unlock(&vnode->lock);
+ }
+
+ ret = 0;
+
+ kunmap(page);
+out_free:
+ page_cache_release(page);
+out:
+ _leave(" = %d", ret);
+ return ret;
+}
+
+/*
+ * no valid lookup procedure on this sort of dir
+ */
+static struct dentry *afs_mntpt_lookup(struct inode *dir,
+ struct dentry *dentry,
+ unsigned int flags)
+{
+ _enter("%p,%p{%pd2}", dir, dentry, dentry);
+ return ERR_PTR(-EREMOTE);
+}
+
+/*
+ * no valid open procedure on this sort of dir
+ */
+static int afs_mntpt_open(struct inode *inode, struct file *file)
+{
+ _enter("%p,%p{%pD2}", inode, file, file);
+ return -EREMOTE;
+}
+
+/*
+ * create a vfsmount to be automounted
+ */
+static struct vfsmount *afs_mntpt_do_automount(struct dentry *mntpt)
+{
+ struct afs_super_info *super;
+ struct vfsmount *mnt;
+ struct afs_vnode *vnode;
+ struct page *page;
+ char *devname, *options;
+ bool rwpath = false;
+ int ret;
+
+ _enter("{%pd}", mntpt);
+
+ BUG_ON(!d_inode(mntpt));
+
+ ret = -ENOMEM;
+ devname = (char *) get_zeroed_page(GFP_KERNEL);
+ if (!devname)
+ goto error_no_devname;
+
+ options = (char *) get_zeroed_page(GFP_KERNEL);
+ if (!options)
+ goto error_no_options;
+
+ vnode = AFS_FS_I(d_inode(mntpt));
+ if (test_bit(AFS_VNODE_PSEUDODIR, &vnode->flags)) {
+ /* if the directory is a pseudo directory, use the d_name */
+ static const char afs_root_cell[] = ":root.cell.";
+ unsigned size = mntpt->d_name.len;
+
+ ret = -ENOENT;
+ if (size < 2 || size > AFS_MAXCELLNAME)
+ goto error_no_page;
+
+ if (mntpt->d_name.name[0] == '.') {
+ devname[0] = '#';
+ memcpy(devname + 1, mntpt->d_name.name, size - 1);
+ memcpy(devname + size, afs_root_cell,
+ sizeof(afs_root_cell));
+ rwpath = true;
+ } else {
+ devname[0] = '%';
+ memcpy(devname + 1, mntpt->d_name.name, size);
+ memcpy(devname + size + 1, afs_root_cell,
+ sizeof(afs_root_cell));
+ }
+ } else {
+ /* read the contents of the AFS special symlink */
+ loff_t size = i_size_read(d_inode(mntpt));
+ char *buf;
+
+ ret = -EINVAL;
+ if (size > PAGE_SIZE - 1)
+ goto error_no_page;
+
+ page = read_mapping_page(d_inode(mntpt)->i_mapping, 0, NULL);
+ if (IS_ERR(page)) {
+ ret = PTR_ERR(page);
+ goto error_no_page;
+ }
+
+ ret = -EIO;
+ if (PageError(page))
+ goto error;
+
+ buf = kmap_atomic(page);
+ memcpy(devname, buf, size);
+ kunmap_atomic(buf);
+ page_cache_release(page);
+ page = NULL;
+ }
+
+ /* work out what options we want */
+ super = AFS_FS_S(mntpt->d_sb);
+ memcpy(options, "cell=", 5);
+ strcpy(options + 5, super->volume->cell->name);
+ if (super->volume->type == AFSVL_RWVOL || rwpath)
+ strcat(options, ",rwpath");
+
+ /* try and do the mount */
+ _debug("--- attempting mount %s -o %s ---", devname, options);
+ mnt = vfs_kern_mount(&afs_fs_type, 0, devname, options);
+ _debug("--- mount result %p ---", mnt);
+
+ free_page((unsigned long) devname);
+ free_page((unsigned long) options);
+ _leave(" = %p", mnt);
+ return mnt;
+
+error:
+ page_cache_release(page);
+error_no_page:
+ free_page((unsigned long) options);
+error_no_options:
+ free_page((unsigned long) devname);
+error_no_devname:
+ _leave(" = %d", ret);
+ return ERR_PTR(ret);
+}
+
+/*
+ * handle an automount point
+ */
+struct vfsmount *afs_d_automount(struct path *path)
+{
+ struct vfsmount *newmnt;
+
+ _enter("{%pd}", path->dentry);
+
+ newmnt = afs_mntpt_do_automount(path->dentry);
+ if (IS_ERR(newmnt))
+ return newmnt;
+
+ mntget(newmnt); /* prevent immediate expiration */
+ mnt_set_expiry(newmnt, &afs_vfsmounts);
+ queue_delayed_work(afs_wq, &afs_mntpt_expiry_timer,
+ afs_mntpt_expiry_timeout * HZ);
+ _leave(" = %p", newmnt);
+ return newmnt;
+}
+
+/*
+ * handle mountpoint expiry timer going off
+ */
+static void afs_mntpt_expiry_timed_out(struct work_struct *work)
+{
+ _enter("");
+
+ if (!list_empty(&afs_vfsmounts)) {
+ mark_mounts_for_expiry(&afs_vfsmounts);
+ queue_delayed_work(afs_wq, &afs_mntpt_expiry_timer,
+ afs_mntpt_expiry_timeout * HZ);
+ }
+
+ _leave("");
+}
+
+/*
+ * kill the AFS mountpoint timer if it's still running
+ */
+void afs_mntpt_kill_timer(void)
+{
+ _enter("");
+
+ ASSERT(list_empty(&afs_vfsmounts));
+ cancel_delayed_work_sync(&afs_mntpt_expiry_timer);
+}
Code Review / kvmfornfv.git / blobdiff