[PATCH v2 32/40] afs: Move the vnode/volume validity checking code into its own file

David Howells
2023-12-13T13:51:03Z

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
---
fs/afs/Makefile | 1 +
fs/afs/inode.c | 172 -----------------------------------------
fs/afs/internal.h | 10 ++-
fs/afs/validation.c | 183 ++++++++++++++++++++++++++++++++++++++++++++
4 files changed, 191 insertions(+), 175 deletions(-)
create mode 100644 fs/afs/validation.c

diff --git a/fs/afs/Makefile b/fs/afs/Makefile
index b3849bea0553..dcdc0f1bb76f 100644
--- a/fs/afs/Makefile
+++ b/fs/afs/Makefile
@@ -28,6 +28,7 @@ kafs-y := \
server.o \
server_list.o \
super.o \
+ validation.o \
vlclient.o \
vl_alias.o \
vl_list.o \
diff --git a/fs/afs/inode.c b/fs/afs/inode.c
index f44a8a48bf24..102e7c37d33c 100644
--- a/fs/afs/inode.c
+++ b/fs/afs/inode.c
@@ -572,178 +572,6 @@ struct inode *afs_root_iget(struct super_block *sb, struct key *key)
return ERR_PTR(ret);
}

-/*
- * mark the data attached to an inode as obsolete due to a write on the server
- * - might also want to ditch all the outstanding writes and dirty pages
- */
-static void afs_zap_data(struct afs_vnode *vnode)
-{
- _enter("{%llx:%llu}", vnode->fid.vid, vnode->fid.vnode);
-
- afs_invalidate_cache(vnode, 0);
-
- /* nuke all the non-dirty pages that aren't locked, mapped or being
- * written back in a regular file and completely discard the pages in a
- * directory or symlink */
- if (S_ISREG(vnode->netfs.inode.i_mode))
- invalidate_remote_inode(&vnode->netfs.inode);
- else
- invalidate_inode_pages2(vnode->netfs.inode.i_mapping);
-}
-
-/*
- * Check to see if we have a server currently serving this volume and that it
- * hasn't been reinitialised or dropped from the list.
- */
-static bool afs_check_server_good(struct afs_vnode *vnode)
-{
- struct afs_server_list *slist;
- struct afs_server *server;
- bool good;
- int i;
-
- if (vnode->cb_fs_s_break == atomic_read(&vnode->volume->cell->fs_s_break))
- return true;
-
- rcu_read_lock();
-
- slist = rcu_dereference(vnode->volume->servers);
- for (i = 0; i < slist->nr_servers; i++) {
- server = slist->servers[i].server;
- if (server == vnode->cb_server) {
- good = (vnode->cb_s_break == server->cb_s_break);
- rcu_read_unlock();
- return good;
- }
- }
-
- rcu_read_unlock();
- return false;
-}
-
-/*
- * Check the validity of a vnode/inode.
- */
-bool afs_check_validity(struct afs_vnode *vnode)
-{
- enum afs_cb_break_reason need_clear = afs_cb_break_no_break;
- time64_t now = ktime_get_real_seconds();
- unsigned int cb_break;
- int seq;
-
- do {
- seq = read_seqbegin(&vnode->cb_lock);
- cb_break = vnode->cb_break;
-
- if (test_bit(AFS_VNODE_CB_PROMISED, &vnode->flags)) {
- if (vnode->cb_v_break != vnode->volume->cb_v_break)
- need_clear = afs_cb_break_for_v_break;
- else if (!afs_check_server_good(vnode))
- need_clear = afs_cb_break_for_s_reinit;
- else if (test_bit(AFS_VNODE_ZAP_DATA, &vnode->flags))
- need_clear = afs_cb_break_for_zap;
- else if (vnode->cb_expires_at - 10 <= now)
- need_clear = afs_cb_break_for_lapsed;
- } else if (test_bit(AFS_VNODE_DELETED, &vnode->flags)) {
- ;
- } else {
- need_clear = afs_cb_break_no_promise;
- }
-
- } while (read_seqretry(&vnode->cb_lock, seq));
-
- if (need_clear == afs_cb_break_no_break)
- return true;
-
- write_seqlock(&vnode->cb_lock);
- if (need_clear == afs_cb_break_no_promise)
- vnode->cb_v_break = vnode->volume->cb_v_break;
- else if (cb_break == vnode->cb_break)
- __afs_break_callback(vnode, need_clear);
- else
- trace_afs_cb_miss(&vnode->fid, need_clear);
- write_sequnlock(&vnode->cb_lock);
- return false;
-}
-
-/*
- * Returns true if the pagecache is still valid. Does not sleep.
- */
-bool afs_pagecache_valid(struct afs_vnode *vnode)
-{
- if (unlikely(test_bit(AFS_VNODE_DELETED, &vnode->flags))) {
- if (vnode->netfs.inode.i_nlink)
- clear_nlink(&vnode->netfs.inode);
- return true;
- }
-
- if (test_bit(AFS_VNODE_CB_PROMISED, &vnode->flags) &&
- afs_check_validity(vnode))
- return true;
-
- return false;
-}
-
-/*
- * validate a vnode/inode
- * - there are several things we need to check
- * - parent dir data changes (rm, rmdir, rename, mkdir, create, link,
- * symlink)
- * - parent dir metadata changed (security changes)
- * - dentry data changed (write, truncate)
- * - dentry metadata changed (security changes)
- */
-int afs_validate(struct afs_vnode *vnode, struct key *key)
-{
- int ret;
-
- _enter("{v={%llx:%llu} fl=%lx},%x",
- vnode->fid.vid, vnode->fid.vnode, vnode->flags,
- key_serial(key));
-
- if (afs_pagecache_valid(vnode))
- goto valid;
-
- down_write(&vnode->validate_lock);
-
- /* if the promise has expired, we need to check the server again to get
- * a new promise - note that if the (parent) directory's metadata was
- * changed then the security may be different and we may no longer have
- * access */
- if (!test_bit(AFS_VNODE_CB_PROMISED, &vnode->flags)) {
- _debug("not promised");
- ret = afs_fetch_status(vnode, key, false, NULL);
- if (ret < 0) {
- if (ret == -ENOENT) {
- set_bit(AFS_VNODE_DELETED, &vnode->flags);
- ret = -ESTALE;
- }
- goto error_unlock;
- }
- _debug("new promise [fl=%lx]", vnode->flags);
- }
-
- if (test_bit(AFS_VNODE_DELETED, &vnode->flags)) {
- _debug("file already deleted");
- ret = -ESTALE;
- goto error_unlock;
- }
-
- /* if the vnode's data version number changed then its contents are
- * different */
- if (test_and_clear_bit(AFS_VNODE_ZAP_DATA, &vnode->flags))
- afs_zap_data(vnode);
- up_write(&vnode->validate_lock);
-valid:
- _leave(" = 0");
- return 0;
-
-error_unlock:
- up_write(&vnode->validate_lock);
- _leave(" = %d", ret);
- return ret;
-}
-
/*
* read the attributes of an inode
*/
diff --git a/fs/afs/internal.h b/fs/afs/internal.h
index a50dfb2f8d7d..4a3d946b1d2a 100644
--- a/fs/afs/internal.h
+++ b/fs/afs/internal.h
@@ -1235,9 +1235,6 @@ extern int afs_ilookup5_test_by_fid(struct inode *, void *);
extern struct inode *afs_iget_pseudo_dir(struct super_block *, bool);
extern struct inode *afs_iget(struct afs_operation *, struct afs_vnode_param *);
extern struct inode *afs_root_iget(struct super_block *, struct key *);
-extern bool afs_check_validity(struct afs_vnode *);
-extern int afs_validate(struct afs_vnode *, struct key *);
-bool afs_pagecache_valid(struct afs_vnode *);
extern int afs_getattr(struct mnt_idmap *idmap, const struct path *,
struct kstat *, u32, unsigned int);
extern int afs_setattr(struct mnt_idmap *idmap, struct dentry *, struct iattr *);
@@ -1547,6 +1544,13 @@ void afs_detach_volume_from_servers(struct afs_volume *volume, struct afs_server
extern int __init afs_fs_init(void);
extern void afs_fs_exit(void);

+/*
+ * validation.c
+ */
+bool afs_check_validity(struct afs_vnode *vnode);
+bool afs_pagecache_valid(struct afs_vnode *vnode);
+int afs_validate(struct afs_vnode *vnode, struct key *key);
+
/*
* vlclient.c
*/
diff --git a/fs/afs/validation.c b/fs/afs/validation.c
new file mode 100644
index 000000000000..18ba2c5e8ead
--- /dev/null
+++ b/fs/afs/validation.c
@@ -0,0 +1,183 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* vnode and volume validity verification.
+ *
+ * Copyright (C) 2023 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/sched.h>
+#include "internal.h"
+
+/*
+ * mark the data attached to an inode as obsolete due to a write on the server
+ * - might also want to ditch all the outstanding writes and dirty pages
+ */
+static void afs_zap_data(struct afs_vnode *vnode)
+{
+ _enter("{%llx:%llu}", vnode->fid.vid, vnode->fid.vnode);
+
+ afs_invalidate_cache(vnode, 0);
+
+ /* nuke all the non-dirty pages that aren't locked, mapped or being
+ * written back in a regular file and completely discard the pages in a
+ * directory or symlink */
+ if (S_ISREG(vnode->netfs.inode.i_mode))
+ invalidate_remote_inode(&vnode->netfs.inode);
+ else
+ invalidate_inode_pages2(vnode->netfs.inode.i_mapping);
+}
+
+/*
+ * Check to see if we have a server currently serving this volume and that it
+ * hasn't been reinitialised or dropped from the list.
+ */
+static bool afs_check_server_good(struct afs_vnode *vnode)
+{
+ struct afs_server_list *slist;
+ struct afs_server *server;
+ bool good;
+ int i;
+
+ if (vnode->cb_fs_s_break == atomic_read(&vnode->volume->cell->fs_s_break))
+ return true;
+
+ rcu_read_lock();
+
+ slist = rcu_dereference(vnode->volume->servers);
+ for (i = 0; i < slist->nr_servers; i++) {
+ server = slist->servers[i].server;
+ if (server == vnode->cb_server) {
+ good = (vnode->cb_s_break == server->cb_s_break);
+ rcu_read_unlock();
+ return good;
+ }
+ }
+
+ rcu_read_unlock();
+ return false;
+}
+
+/*
+ * Check the validity of a vnode/inode.
+ */
+bool afs_check_validity(struct afs_vnode *vnode)
+{
+ enum afs_cb_break_reason need_clear = afs_cb_break_no_break;
+ time64_t now = ktime_get_real_seconds();
+ unsigned int cb_break;
+ int seq;
+
+ do {
+ seq = read_seqbegin(&vnode->cb_lock);
+ cb_break = vnode->cb_break;
+
+ if (test_bit(AFS_VNODE_CB_PROMISED, &vnode->flags)) {
+ if (vnode->cb_v_break != vnode->volume->cb_v_break)
+ need_clear = afs_cb_break_for_v_break;
+ else if (!afs_check_server_good(vnode))
+ need_clear = afs_cb_break_for_s_reinit;
+ else if (test_bit(AFS_VNODE_ZAP_DATA, &vnode->flags))
+ need_clear = afs_cb_break_for_zap;
+ else if (vnode->cb_expires_at - 10 <= now)
+ need_clear = afs_cb_break_for_lapsed;
+ } else if (test_bit(AFS_VNODE_DELETED, &vnode->flags)) {
+ ;
+ } else {
+ need_clear = afs_cb_break_no_promise;
+ }
+
+ } while (read_seqretry(&vnode->cb_lock, seq));
+
+ if (need_clear == afs_cb_break_no_break)
+ return true;
+
+ write_seqlock(&vnode->cb_lock);
+ if (need_clear == afs_cb_break_no_promise)
+ vnode->cb_v_break = vnode->volume->cb_v_break;
+ else if (cb_break == vnode->cb_break)
+ __afs_break_callback(vnode, need_clear);
+ else
+ trace_afs_cb_miss(&vnode->fid, need_clear);
+ write_sequnlock(&vnode->cb_lock);
+ return false;
+}
+
+/*
+ * Returns true if the pagecache is still valid. Does not sleep.
+ */
+bool afs_pagecache_valid(struct afs_vnode *vnode)
+{
+ if (unlikely(test_bit(AFS_VNODE_DELETED, &vnode->flags))) {
+ if (vnode->netfs.inode.i_nlink)
+ clear_nlink(&vnode->netfs.inode);
+ return true;
+ }
+
+ if (test_bit(AFS_VNODE_CB_PROMISED, &vnode->flags) &&
+ afs_check_validity(vnode))
+ return true;
+
+ return false;
+}
+
+/*
+ * validate a vnode/inode
+ * - there are several things we need to check
+ * - parent dir data changes (rm, rmdir, rename, mkdir, create, link,
+ * symlink)
+ * - parent dir metadata changed (security changes)
+ * - dentry data changed (write, truncate)
+ * - dentry metadata changed (security changes)
+ */
+int afs_validate(struct afs_vnode *vnode, struct key *key)
+{
+ int ret;
+
+ _enter("{v={%llx:%llu} fl=%lx},%x",
+ vnode->fid.vid, vnode->fid.vnode, vnode->flags,
+ key_serial(key));
+
+ if (afs_pagecache_valid(vnode))
+ goto valid;
+
+ down_write(&vnode->validate_lock);
+
+ /* if the promise has expired, we need to check the server again to get
+ * a new promise - note that if the (parent) directory's metadata was
+ * changed then the security may be different and we may no longer have
+ * access */
+ if (!test_bit(AFS_VNODE_CB_PROMISED, &vnode->flags)) {
+ _debug("not promised");
+ ret = afs_fetch_status(vnode, key, false, NULL);
+ if (ret < 0) {
+ if (ret == -ENOENT) {
+ set_bit(AFS_VNODE_DELETED, &vnode->flags);
+ ret = -ESTALE;
+ }
+ goto error_unlock;
+ }
+ _debug("new promise [fl=%lx]", vnode->flags);
+ }
+
+ if (test_bit(AFS_VNODE_DELETED, &vnode->flags)) {
+ _debug("file already deleted");
+ ret = -ESTALE;
+ goto error_unlock;
+ }
+
+ /* if the vnode's data version number changed then its contents are
+ * different */
+ if (test_and_clear_bit(AFS_VNODE_ZAP_DATA, &vnode->flags))
+ afs_zap_data(vnode);
+ up_write(&vnode->validate_lock);
+valid:
+ _leave(" = 0");
+ return 0;
+
+error_unlock:
+ up_write(&vnode->validate_lock);
+ _leave(" = %d", ret);
+ return ret;
+}