afs: Move the vnode/volume validity checking code into its own file
Move the code that does validity checking of vnodes and volumes with respect to third-party changes into its own file. Signed-off-by: David Howells <dhowells@redhat.com> cc: Marc Dionne <marc.dionne@auristor.com> cc: linux-afs@lists.infradead.org
This commit is contained in:
David Howells
parent
445f9b6952
commit
dfa0a44946
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@ -28,6 +28,7 @@ kafs-y := \
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server.o \
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server_list.o \
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super.o \
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validation.o \
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vlclient.o \
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vl_alias.o \
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vl_list.o \
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172
fs/afs/inode.c
172
fs/afs/inode.c
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@ -572,178 +572,6 @@ error:
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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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static void afs_zap_data(struct afs_vnode *vnode)
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{
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_enter("{%llx:%llu}", vnode->fid.vid, vnode->fid.vnode);
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afs_invalidate_cache(vnode, 0);
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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->netfs.inode.i_mode))
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invalidate_remote_inode(&vnode->netfs.inode);
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else
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invalidate_inode_pages2(vnode->netfs.inode.i_mapping);
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}
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/*
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* Check to see if we have a server currently serving this volume and that it
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* hasn't been reinitialised or dropped from the list.
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*/
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static bool afs_check_server_good(struct afs_vnode *vnode)
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{
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struct afs_server_list *slist;
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struct afs_server *server;
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bool good;
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int i;
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if (vnode->cb_fs_s_break == atomic_read(&vnode->volume->cell->fs_s_break))
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return true;
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rcu_read_lock();
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slist = rcu_dereference(vnode->volume->servers);
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for (i = 0; i < slist->nr_servers; i++) {
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server = slist->servers[i].server;
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if (server == vnode->cb_server) {
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good = (vnode->cb_s_break == server->cb_s_break);
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rcu_read_unlock();
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return good;
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}
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}
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rcu_read_unlock();
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return false;
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}
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/*
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* Check the validity of a vnode/inode.
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*/
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bool afs_check_validity(struct afs_vnode *vnode)
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{
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enum afs_cb_break_reason need_clear = afs_cb_break_no_break;
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time64_t now = ktime_get_real_seconds();
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unsigned int cb_break;
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int seq;
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do {
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seq = read_seqbegin(&vnode->cb_lock);
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cb_break = vnode->cb_break;
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if (test_bit(AFS_VNODE_CB_PROMISED, &vnode->flags)) {
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if (vnode->cb_v_break != vnode->volume->cb_v_break)
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need_clear = afs_cb_break_for_v_break;
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else if (!afs_check_server_good(vnode))
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need_clear = afs_cb_break_for_s_reinit;
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else if (test_bit(AFS_VNODE_ZAP_DATA, &vnode->flags))
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need_clear = afs_cb_break_for_zap;
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else if (vnode->cb_expires_at - 10 <= now)
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need_clear = afs_cb_break_for_lapsed;
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} else if (test_bit(AFS_VNODE_DELETED, &vnode->flags)) {
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;
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} else {
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need_clear = afs_cb_break_no_promise;
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}
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} while (read_seqretry(&vnode->cb_lock, seq));
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if (need_clear == afs_cb_break_no_break)
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return true;
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write_seqlock(&vnode->cb_lock);
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if (need_clear == afs_cb_break_no_promise)
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vnode->cb_v_break = vnode->volume->cb_v_break;
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else if (cb_break == vnode->cb_break)
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__afs_break_callback(vnode, need_clear);
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else
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trace_afs_cb_miss(&vnode->fid, need_clear);
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write_sequnlock(&vnode->cb_lock);
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return false;
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}
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/*
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* Returns true if the pagecache is still valid. Does not sleep.
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*/
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bool afs_pagecache_valid(struct afs_vnode *vnode)
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{
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if (unlikely(test_bit(AFS_VNODE_DELETED, &vnode->flags))) {
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if (vnode->netfs.inode.i_nlink)
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clear_nlink(&vnode->netfs.inode);
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return true;
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}
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if (test_bit(AFS_VNODE_CB_PROMISED, &vnode->flags) &&
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afs_check_validity(vnode))
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return true;
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return false;
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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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int ret;
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_enter("{v={%llx:%llu} 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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if (afs_pagecache_valid(vnode))
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goto valid;
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down_write(&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, false, NULL);
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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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up_write(&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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up_write(&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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@ -1235,9 +1235,6 @@ extern int afs_ilookup5_test_by_fid(struct inode *, void *);
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extern struct inode *afs_iget_pseudo_dir(struct super_block *, bool);
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extern struct inode *afs_iget(struct afs_operation *, struct afs_vnode_param *);
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extern struct inode *afs_root_iget(struct super_block *, struct key *);
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extern bool afs_check_validity(struct afs_vnode *);
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extern int afs_validate(struct afs_vnode *, struct key *);
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bool afs_pagecache_valid(struct afs_vnode *);
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extern int afs_getattr(struct mnt_idmap *idmap, const struct path *,
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struct kstat *, u32, unsigned int);
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extern int afs_setattr(struct mnt_idmap *idmap, struct dentry *, struct iattr *);
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@ -1547,6 +1544,13 @@ void afs_detach_volume_from_servers(struct afs_volume *volume, struct afs_server
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extern int __init afs_fs_init(void);
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extern void afs_fs_exit(void);
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/*
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* validation.c
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*/
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bool afs_check_validity(struct afs_vnode *vnode);
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bool afs_pagecache_valid(struct afs_vnode *vnode);
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int afs_validate(struct afs_vnode *vnode, struct key *key);
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/*
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* vlclient.c
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*/
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@ -0,0 +1,183 @@
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// SPDX-License-Identifier: GPL-2.0-or-later
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/* vnode and volume validity verification.
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*
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* Copyright (C) 2023 Red Hat, Inc. All Rights Reserved.
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* Written by David Howells (dhowells@redhat.com)
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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/sched.h>
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#include "internal.h"
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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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static void afs_zap_data(struct afs_vnode *vnode)
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{
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_enter("{%llx:%llu}", vnode->fid.vid, vnode->fid.vnode);
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afs_invalidate_cache(vnode, 0);
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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->netfs.inode.i_mode))
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invalidate_remote_inode(&vnode->netfs.inode);
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else
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invalidate_inode_pages2(vnode->netfs.inode.i_mapping);
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}
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/*
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* Check to see if we have a server currently serving this volume and that it
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* hasn't been reinitialised or dropped from the list.
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*/
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static bool afs_check_server_good(struct afs_vnode *vnode)
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{
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struct afs_server_list *slist;
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struct afs_server *server;
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bool good;
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int i;
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if (vnode->cb_fs_s_break == atomic_read(&vnode->volume->cell->fs_s_break))
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return true;
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rcu_read_lock();
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slist = rcu_dereference(vnode->volume->servers);
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for (i = 0; i < slist->nr_servers; i++) {
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server = slist->servers[i].server;
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if (server == vnode->cb_server) {
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good = (vnode->cb_s_break == server->cb_s_break);
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rcu_read_unlock();
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return good;
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}
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}
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rcu_read_unlock();
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return false;
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}
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/*
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* Check the validity of a vnode/inode.
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*/
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bool afs_check_validity(struct afs_vnode *vnode)
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{
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enum afs_cb_break_reason need_clear = afs_cb_break_no_break;
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time64_t now = ktime_get_real_seconds();
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unsigned int cb_break;
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int seq;
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do {
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seq = read_seqbegin(&vnode->cb_lock);
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cb_break = vnode->cb_break;
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if (test_bit(AFS_VNODE_CB_PROMISED, &vnode->flags)) {
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if (vnode->cb_v_break != vnode->volume->cb_v_break)
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need_clear = afs_cb_break_for_v_break;
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else if (!afs_check_server_good(vnode))
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need_clear = afs_cb_break_for_s_reinit;
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else if (test_bit(AFS_VNODE_ZAP_DATA, &vnode->flags))
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need_clear = afs_cb_break_for_zap;
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else if (vnode->cb_expires_at - 10 <= now)
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need_clear = afs_cb_break_for_lapsed;
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} else if (test_bit(AFS_VNODE_DELETED, &vnode->flags)) {
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;
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} else {
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need_clear = afs_cb_break_no_promise;
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}
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} while (read_seqretry(&vnode->cb_lock, seq));
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if (need_clear == afs_cb_break_no_break)
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return true;
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write_seqlock(&vnode->cb_lock);
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if (need_clear == afs_cb_break_no_promise)
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vnode->cb_v_break = vnode->volume->cb_v_break;
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else if (cb_break == vnode->cb_break)
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__afs_break_callback(vnode, need_clear);
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else
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trace_afs_cb_miss(&vnode->fid, need_clear);
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write_sequnlock(&vnode->cb_lock);
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return false;
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}
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/*
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* Returns true if the pagecache is still valid. Does not sleep.
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*/
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bool afs_pagecache_valid(struct afs_vnode *vnode)
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{
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if (unlikely(test_bit(AFS_VNODE_DELETED, &vnode->flags))) {
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if (vnode->netfs.inode.i_nlink)
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clear_nlink(&vnode->netfs.inode);
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return true;
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}
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if (test_bit(AFS_VNODE_CB_PROMISED, &vnode->flags) &&
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afs_check_validity(vnode))
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return true;
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return false;
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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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int ret;
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_enter("{v={%llx:%llu} 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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if (afs_pagecache_valid(vnode))
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goto valid;
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down_write(&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, false, NULL);
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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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up_write(&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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up_write(&vnode->validate_lock);
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_leave(" = %d", ret);
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return ret;
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}
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