![David Howells](/assets/img/avatar_default.png)
Support the AFS dynamic root which is a pseudo-volume that doesn't connect to any server resource, but rather is just a root directory that dynamically creates mountpoint directories where the name of such a directory is the name of the cell. Such a mount can be created thus: mount -t afs none /afs -o dyn Dynamic root superblocks aren't shared except by bind mounts and propagation. Cell root volumes can then be mounted by referring to them by name, e.g.: ls /afs/grand.central.org/ ls /afs/.grand.central.org/ The kernel will upcall to consult the DNS if the address wasn't supplied directly. Signed-off-by: David Howells <dhowells@redhat.com>
571 lines
14 KiB
C
571 lines
14 KiB
C
/*
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* Copyright (c) 2002 Red Hat, Inc. All rights reserved.
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*
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* This software may be freely redistributed under the terms of the
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* GNU General Public License.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*
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* Authors: David Woodhouse <dwmw2@infradead.org>
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* David Howells <dhowells@redhat.com>
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*
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*/
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/init.h>
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#include <linux/fs.h>
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#include <linux/pagemap.h>
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#include <linux/sched.h>
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#include <linux/mount.h>
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#include <linux/namei.h>
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#include <linux/iversion.h>
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#include "internal.h"
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static const struct inode_operations afs_symlink_inode_operations = {
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.get_link = page_get_link,
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.listxattr = afs_listxattr,
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};
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/*
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* map the AFS file status to the inode member variables
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*/
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static int afs_inode_map_status(struct afs_vnode *vnode, struct key *key)
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{
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struct inode *inode = AFS_VNODE_TO_I(vnode);
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bool changed;
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_debug("FS: ft=%d lk=%d sz=%llu ver=%Lu mod=%hu",
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vnode->status.type,
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vnode->status.nlink,
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(unsigned long long) vnode->status.size,
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vnode->status.data_version,
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vnode->status.mode);
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read_seqlock_excl(&vnode->cb_lock);
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switch (vnode->status.type) {
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case AFS_FTYPE_FILE:
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inode->i_mode = S_IFREG | vnode->status.mode;
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inode->i_op = &afs_file_inode_operations;
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inode->i_fop = &afs_file_operations;
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break;
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case AFS_FTYPE_DIR:
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inode->i_mode = S_IFDIR | vnode->status.mode;
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inode->i_op = &afs_dir_inode_operations;
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inode->i_fop = &afs_dir_file_operations;
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break;
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case AFS_FTYPE_SYMLINK:
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/* Symlinks with a mode of 0644 are actually mountpoints. */
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if ((vnode->status.mode & 0777) == 0644) {
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inode->i_flags |= S_AUTOMOUNT;
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set_bit(AFS_VNODE_MOUNTPOINT, &vnode->flags);
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inode->i_mode = S_IFDIR | 0555;
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inode->i_op = &afs_mntpt_inode_operations;
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inode->i_fop = &afs_mntpt_file_operations;
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} else {
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inode->i_mode = S_IFLNK | vnode->status.mode;
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inode->i_op = &afs_symlink_inode_operations;
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}
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inode_nohighmem(inode);
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break;
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default:
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printk("kAFS: AFS vnode with undefined type\n");
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read_sequnlock_excl(&vnode->cb_lock);
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return -EBADMSG;
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}
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changed = (vnode->status.size != inode->i_size);
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set_nlink(inode, vnode->status.nlink);
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inode->i_uid = vnode->status.owner;
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inode->i_gid = vnode->status.group;
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inode->i_size = vnode->status.size;
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inode->i_ctime.tv_sec = vnode->status.mtime_client;
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inode->i_ctime.tv_nsec = 0;
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inode->i_atime = inode->i_mtime = inode->i_ctime;
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inode->i_blocks = 0;
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inode->i_generation = vnode->fid.unique;
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inode_set_iversion_raw(inode, vnode->status.data_version);
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inode->i_mapping->a_ops = &afs_fs_aops;
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read_sequnlock_excl(&vnode->cb_lock);
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#ifdef CONFIG_AFS_FSCACHE
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if (changed)
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fscache_attr_changed(vnode->cache);
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#endif
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return 0;
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}
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/*
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* Fetch file status from the volume.
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*/
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int afs_fetch_status(struct afs_vnode *vnode, struct key *key)
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{
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struct afs_fs_cursor fc;
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int ret;
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_enter("%s,{%x:%u.%u,S=%lx}",
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vnode->volume->name,
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vnode->fid.vid, vnode->fid.vnode, vnode->fid.unique,
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vnode->flags);
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ret = -ERESTARTSYS;
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if (afs_begin_vnode_operation(&fc, vnode, key)) {
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while (afs_select_fileserver(&fc)) {
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fc.cb_break = vnode->cb_break + vnode->cb_s_break;
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afs_fs_fetch_file_status(&fc, NULL);
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}
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afs_check_for_remote_deletion(&fc, fc.vnode);
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afs_vnode_commit_status(&fc, vnode, fc.cb_break);
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ret = afs_end_vnode_operation(&fc);
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}
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_leave(" = %d", ret);
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return ret;
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}
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/*
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* iget5() comparator
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*/
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int afs_iget5_test(struct inode *inode, void *opaque)
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{
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struct afs_iget_data *data = opaque;
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return inode->i_ino == data->fid.vnode &&
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inode->i_generation == data->fid.unique;
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}
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/*
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* iget5() comparator for inode created by autocell operations
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*
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* These pseudo inodes don't match anything.
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*/
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static int afs_iget5_pseudo_dir_test(struct inode *inode, void *opaque)
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{
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return 0;
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}
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/*
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* iget5() inode initialiser
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*/
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static int afs_iget5_set(struct inode *inode, void *opaque)
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{
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struct afs_iget_data *data = opaque;
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struct afs_vnode *vnode = AFS_FS_I(inode);
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inode->i_ino = data->fid.vnode;
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inode->i_generation = data->fid.unique;
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vnode->fid = data->fid;
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vnode->volume = data->volume;
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return 0;
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}
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/*
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* Create an inode for a dynamic root directory or an autocell dynamic
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* automount dir.
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*/
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struct inode *afs_iget_pseudo_dir(struct super_block *sb, bool root)
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{
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struct afs_iget_data data;
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struct afs_super_info *as;
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struct afs_vnode *vnode;
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struct inode *inode;
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static atomic_t afs_autocell_ino;
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_enter("");
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as = sb->s_fs_info;
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if (as->volume) {
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data.volume = as->volume;
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data.fid.vid = as->volume->vid;
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}
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if (root) {
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data.fid.vnode = 1;
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data.fid.unique = 1;
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} else {
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data.fid.vnode = atomic_inc_return(&afs_autocell_ino);
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data.fid.unique = 0;
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}
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inode = iget5_locked(sb, data.fid.vnode,
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afs_iget5_pseudo_dir_test, afs_iget5_set,
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&data);
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if (!inode) {
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_leave(" = -ENOMEM");
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return ERR_PTR(-ENOMEM);
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}
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_debug("GOT INODE %p { ino=%lu, vl=%x, vn=%x, u=%x }",
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inode, inode->i_ino, data.fid.vid, data.fid.vnode,
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data.fid.unique);
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vnode = AFS_FS_I(inode);
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/* there shouldn't be an existing inode */
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BUG_ON(!(inode->i_state & I_NEW));
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inode->i_size = 0;
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inode->i_mode = S_IFDIR | S_IRUGO | S_IXUGO;
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if (root) {
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inode->i_op = &afs_dynroot_inode_operations;
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inode->i_fop = &afs_dynroot_file_operations;
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} else {
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inode->i_op = &afs_autocell_inode_operations;
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}
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set_nlink(inode, 2);
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inode->i_uid = GLOBAL_ROOT_UID;
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inode->i_gid = GLOBAL_ROOT_GID;
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inode->i_ctime.tv_sec = get_seconds();
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inode->i_ctime.tv_nsec = 0;
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inode->i_atime = inode->i_mtime = inode->i_ctime;
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inode->i_blocks = 0;
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inode_set_iversion_raw(inode, 0);
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inode->i_generation = 0;
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set_bit(AFS_VNODE_PSEUDODIR, &vnode->flags);
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if (!root) {
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set_bit(AFS_VNODE_MOUNTPOINT, &vnode->flags);
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inode->i_flags |= S_AUTOMOUNT;
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}
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inode->i_flags |= S_NOATIME;
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unlock_new_inode(inode);
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_leave(" = %p", inode);
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return inode;
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}
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/*
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* inode retrieval
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*/
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struct inode *afs_iget(struct super_block *sb, struct key *key,
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struct afs_fid *fid, struct afs_file_status *status,
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struct afs_callback *cb, struct afs_cb_interest *cbi)
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{
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struct afs_iget_data data = { .fid = *fid };
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struct afs_super_info *as;
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struct afs_vnode *vnode;
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struct inode *inode;
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int ret;
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_enter(",{%x:%u.%u},,", fid->vid, fid->vnode, fid->unique);
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as = sb->s_fs_info;
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data.volume = as->volume;
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inode = iget5_locked(sb, fid->vnode, afs_iget5_test, afs_iget5_set,
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&data);
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if (!inode) {
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_leave(" = -ENOMEM");
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return ERR_PTR(-ENOMEM);
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}
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_debug("GOT INODE %p { vl=%x vn=%x, u=%x }",
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inode, fid->vid, fid->vnode, fid->unique);
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vnode = AFS_FS_I(inode);
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/* deal with an existing inode */
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if (!(inode->i_state & I_NEW)) {
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_leave(" = %p", inode);
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return inode;
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}
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if (!status) {
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/* it's a remotely extant inode */
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ret = afs_fetch_status(vnode, key);
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if (ret < 0)
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goto bad_inode;
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} else {
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/* it's an inode we just created */
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memcpy(&vnode->status, status, sizeof(vnode->status));
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if (!cb) {
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/* it's a symlink we just created (the fileserver
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* didn't give us a callback) */
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vnode->cb_version = 0;
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vnode->cb_type = 0;
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vnode->cb_expires_at = 0;
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} else {
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vnode->cb_version = cb->version;
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vnode->cb_type = cb->type;
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vnode->cb_expires_at = cb->expiry;
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vnode->cb_interest = afs_get_cb_interest(cbi);
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set_bit(AFS_VNODE_CB_PROMISED, &vnode->flags);
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}
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vnode->cb_expires_at += ktime_get_real_seconds();
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}
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/* set up caching before mapping the status, as map-status reads the
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* first page of symlinks to see if they're really mountpoints */
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inode->i_size = vnode->status.size;
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#ifdef CONFIG_AFS_FSCACHE
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vnode->cache = fscache_acquire_cookie(vnode->volume->cache,
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&afs_vnode_cache_index_def,
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vnode, true);
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#endif
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ret = afs_inode_map_status(vnode, key);
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if (ret < 0)
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goto bad_inode;
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/* success */
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clear_bit(AFS_VNODE_UNSET, &vnode->flags);
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inode->i_flags |= S_NOATIME;
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unlock_new_inode(inode);
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_leave(" = %p [CB { v=%u t=%u }]", inode, vnode->cb_version, vnode->cb_type);
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return inode;
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/* failure */
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bad_inode:
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#ifdef CONFIG_AFS_FSCACHE
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fscache_relinquish_cookie(vnode->cache, 0);
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vnode->cache = NULL;
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#endif
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iget_failed(inode);
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_leave(" = %d [bad]", ret);
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return ERR_PTR(ret);
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}
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/*
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* mark the data attached to an inode as obsolete due to a write on the server
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* - might also want to ditch all the outstanding writes and dirty pages
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*/
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void afs_zap_data(struct afs_vnode *vnode)
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{
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_enter("{%x:%u}", vnode->fid.vid, vnode->fid.vnode);
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/* nuke all the non-dirty pages that aren't locked, mapped or being
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* written back in a regular file and completely discard the pages in a
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* directory or symlink */
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if (S_ISREG(vnode->vfs_inode.i_mode))
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invalidate_remote_inode(&vnode->vfs_inode);
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else
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invalidate_inode_pages2(vnode->vfs_inode.i_mapping);
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}
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/*
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* validate a vnode/inode
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* - there are several things we need to check
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* - parent dir data changes (rm, rmdir, rename, mkdir, create, link,
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* symlink)
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* - parent dir metadata changed (security changes)
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* - dentry data changed (write, truncate)
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* - dentry metadata changed (security changes)
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*/
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int afs_validate(struct afs_vnode *vnode, struct key *key)
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{
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time64_t now = ktime_get_real_seconds();
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bool valid = false;
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int ret;
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_enter("{v={%x:%u} fl=%lx},%x",
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vnode->fid.vid, vnode->fid.vnode, vnode->flags,
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key_serial(key));
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/* Quickly check the callback state. Ideally, we'd use read_seqbegin
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* here, but we have no way to pass the net namespace to the RCU
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* cleanup for the server record.
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*/
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read_seqlock_excl(&vnode->cb_lock);
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if (test_bit(AFS_VNODE_CB_PROMISED, &vnode->flags)) {
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if (vnode->cb_s_break != vnode->cb_interest->server->cb_s_break) {
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vnode->cb_s_break = vnode->cb_interest->server->cb_s_break;
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} else if (!test_bit(AFS_VNODE_DIR_MODIFIED, &vnode->flags) &&
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!test_bit(AFS_VNODE_ZAP_DATA, &vnode->flags) &&
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vnode->cb_expires_at - 10 > now) {
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valid = true;
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}
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} else if (test_bit(AFS_VNODE_DELETED, &vnode->flags)) {
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valid = true;
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}
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read_sequnlock_excl(&vnode->cb_lock);
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if (test_bit(AFS_VNODE_DELETED, &vnode->flags))
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clear_nlink(&vnode->vfs_inode);
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if (valid)
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goto valid;
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mutex_lock(&vnode->validate_lock);
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/* if the promise has expired, we need to check the server again to get
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* a new promise - note that if the (parent) directory's metadata was
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* changed then the security may be different and we may no longer have
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* access */
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if (!test_bit(AFS_VNODE_CB_PROMISED, &vnode->flags)) {
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_debug("not promised");
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ret = afs_fetch_status(vnode, key);
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if (ret < 0) {
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if (ret == -ENOENT) {
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set_bit(AFS_VNODE_DELETED, &vnode->flags);
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ret = -ESTALE;
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}
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goto error_unlock;
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}
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_debug("new promise [fl=%lx]", vnode->flags);
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}
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if (test_bit(AFS_VNODE_DELETED, &vnode->flags)) {
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_debug("file already deleted");
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ret = -ESTALE;
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goto error_unlock;
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}
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/* if the vnode's data version number changed then its contents are
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* different */
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if (test_and_clear_bit(AFS_VNODE_ZAP_DATA, &vnode->flags))
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afs_zap_data(vnode);
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clear_bit(AFS_VNODE_DIR_MODIFIED, &vnode->flags);
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mutex_unlock(&vnode->validate_lock);
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valid:
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_leave(" = 0");
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return 0;
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error_unlock:
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mutex_unlock(&vnode->validate_lock);
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_leave(" = %d", ret);
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return ret;
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}
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/*
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* read the attributes of an inode
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*/
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int afs_getattr(const struct path *path, struct kstat *stat,
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u32 request_mask, unsigned int query_flags)
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{
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struct inode *inode = d_inode(path->dentry);
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struct afs_vnode *vnode = AFS_FS_I(inode);
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int seq = 0;
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_enter("{ ino=%lu v=%u }", inode->i_ino, inode->i_generation);
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do {
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read_seqbegin_or_lock(&vnode->cb_lock, &seq);
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generic_fillattr(inode, stat);
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} while (need_seqretry(&vnode->cb_lock, seq));
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done_seqretry(&vnode->cb_lock, seq);
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return 0;
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}
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/*
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* discard an AFS inode
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*/
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int afs_drop_inode(struct inode *inode)
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{
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_enter("");
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if (test_bit(AFS_VNODE_PSEUDODIR, &AFS_FS_I(inode)->flags))
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return generic_delete_inode(inode);
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else
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return generic_drop_inode(inode);
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}
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/*
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* clear an AFS inode
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*/
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void afs_evict_inode(struct inode *inode)
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{
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struct afs_vnode *vnode;
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vnode = AFS_FS_I(inode);
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_enter("{%x:%u.%d}",
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vnode->fid.vid,
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vnode->fid.vnode,
|
|
vnode->fid.unique);
|
|
|
|
_debug("CLEAR INODE %p", inode);
|
|
|
|
ASSERTCMP(inode->i_ino, ==, vnode->fid.vnode);
|
|
|
|
truncate_inode_pages_final(&inode->i_data);
|
|
clear_inode(inode);
|
|
|
|
if (vnode->cb_interest) {
|
|
afs_put_cb_interest(afs_i2net(inode), vnode->cb_interest);
|
|
vnode->cb_interest = NULL;
|
|
}
|
|
|
|
while (!list_empty(&vnode->wb_keys)) {
|
|
struct afs_wb_key *wbk = list_entry(vnode->wb_keys.next,
|
|
struct afs_wb_key, vnode_link);
|
|
list_del(&wbk->vnode_link);
|
|
afs_put_wb_key(wbk);
|
|
}
|
|
|
|
#ifdef CONFIG_AFS_FSCACHE
|
|
fscache_relinquish_cookie(vnode->cache, 0);
|
|
vnode->cache = NULL;
|
|
#endif
|
|
|
|
afs_put_permits(vnode->permit_cache);
|
|
_leave("");
|
|
}
|
|
|
|
/*
|
|
* set the attributes of an inode
|
|
*/
|
|
int afs_setattr(struct dentry *dentry, struct iattr *attr)
|
|
{
|
|
struct afs_fs_cursor fc;
|
|
struct afs_vnode *vnode = AFS_FS_I(d_inode(dentry));
|
|
struct key *key;
|
|
int ret;
|
|
|
|
_enter("{%x:%u},{n=%pd},%x",
|
|
vnode->fid.vid, vnode->fid.vnode, dentry,
|
|
attr->ia_valid);
|
|
|
|
if (!(attr->ia_valid & (ATTR_SIZE | ATTR_MODE | ATTR_UID | ATTR_GID |
|
|
ATTR_MTIME))) {
|
|
_leave(" = 0 [unsupported]");
|
|
return 0;
|
|
}
|
|
|
|
/* flush any dirty data outstanding on a regular file */
|
|
if (S_ISREG(vnode->vfs_inode.i_mode))
|
|
filemap_write_and_wait(vnode->vfs_inode.i_mapping);
|
|
|
|
if (attr->ia_valid & ATTR_FILE) {
|
|
key = afs_file_key(attr->ia_file);
|
|
} else {
|
|
key = afs_request_key(vnode->volume->cell);
|
|
if (IS_ERR(key)) {
|
|
ret = PTR_ERR(key);
|
|
goto error;
|
|
}
|
|
}
|
|
|
|
ret = -ERESTARTSYS;
|
|
if (afs_begin_vnode_operation(&fc, vnode, key)) {
|
|
while (afs_select_fileserver(&fc)) {
|
|
fc.cb_break = vnode->cb_break + vnode->cb_s_break;
|
|
afs_fs_setattr(&fc, attr);
|
|
}
|
|
|
|
afs_check_for_remote_deletion(&fc, fc.vnode);
|
|
afs_vnode_commit_status(&fc, vnode, fc.cb_break);
|
|
ret = afs_end_vnode_operation(&fc);
|
|
}
|
|
|
|
if (!(attr->ia_valid & ATTR_FILE))
|
|
key_put(key);
|
|
|
|
error:
|
|
_leave(" = %d", ret);
|
|
return ret;
|
|
}
|