summaryrefslogtreecommitdiffstats
path: root/fs/afs/callback.c
diff options
context:
space:
mode:
Diffstat (limited to 'fs/afs/callback.c')
-rw-r--r--fs/afs/callback.c228
1 files changed, 228 insertions, 0 deletions
diff --git a/fs/afs/callback.c b/fs/afs/callback.c
new file mode 100644
index 000000000..a484fa642
--- /dev/null
+++ b/fs/afs/callback.c
@@ -0,0 +1,228 @@
+/*
+ * Copyright (c) 2002, 2007 Red Hat, Inc. All rights reserved.
+ *
+ * This software may be freely redistributed under the terms of the
+ * GNU General Public License.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ *
+ * Authors: David Woodhouse <dwmw2@infradead.org>
+ * David Howells <dhowells@redhat.com>
+ *
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/circ_buf.h>
+#include <linux/sched.h>
+#include "internal.h"
+
+/*
+ * Handle invalidation of an mmap'd file. We invalidate all the PTEs referring
+ * to the pages in this file's pagecache, forcing the kernel to go through
+ * ->fault() or ->page_mkwrite() - at which point we can handle invalidation
+ * more fully.
+ */
+void afs_invalidate_mmap_work(struct work_struct *work)
+{
+ struct afs_vnode *vnode = container_of(work, struct afs_vnode, cb_work);
+
+ unmap_mapping_pages(vnode->netfs.inode.i_mapping, 0, 0, false);
+}
+
+void afs_server_init_callback_work(struct work_struct *work)
+{
+ struct afs_server *server = container_of(work, struct afs_server, initcb_work);
+ struct afs_vnode *vnode;
+ struct afs_cell *cell = server->cell;
+
+ down_read(&cell->fs_open_mmaps_lock);
+
+ list_for_each_entry(vnode, &cell->fs_open_mmaps, cb_mmap_link) {
+ if (vnode->cb_server == server) {
+ clear_bit(AFS_VNODE_CB_PROMISED, &vnode->flags);
+ queue_work(system_unbound_wq, &vnode->cb_work);
+ }
+ }
+
+ up_read(&cell->fs_open_mmaps_lock);
+}
+
+/*
+ * Allow the fileserver to request callback state (re-)initialisation.
+ * Unfortunately, UUIDs are not guaranteed unique.
+ */
+void afs_init_callback_state(struct afs_server *server)
+{
+ rcu_read_lock();
+ do {
+ server->cb_s_break++;
+ atomic_inc(&server->cell->fs_s_break);
+ if (!list_empty(&server->cell->fs_open_mmaps))
+ queue_work(system_unbound_wq, &server->initcb_work);
+
+ } while ((server = rcu_dereference(server->uuid_next)));
+ rcu_read_unlock();
+}
+
+/*
+ * actually break a callback
+ */
+void __afs_break_callback(struct afs_vnode *vnode, enum afs_cb_break_reason reason)
+{
+ _enter("");
+
+ clear_bit(AFS_VNODE_NEW_CONTENT, &vnode->flags);
+ if (test_and_clear_bit(AFS_VNODE_CB_PROMISED, &vnode->flags)) {
+ vnode->cb_break++;
+ vnode->cb_v_break = vnode->volume->cb_v_break;
+ afs_clear_permits(vnode);
+
+ if (vnode->lock_state == AFS_VNODE_LOCK_WAITING_FOR_CB)
+ afs_lock_may_be_available(vnode);
+
+ if (reason != afs_cb_break_for_deleted &&
+ vnode->status.type == AFS_FTYPE_FILE &&
+ atomic_read(&vnode->cb_nr_mmap))
+ queue_work(system_unbound_wq, &vnode->cb_work);
+
+ trace_afs_cb_break(&vnode->fid, vnode->cb_break, reason, true);
+ } else {
+ trace_afs_cb_break(&vnode->fid, vnode->cb_break, reason, false);
+ }
+}
+
+void afs_break_callback(struct afs_vnode *vnode, enum afs_cb_break_reason reason)
+{
+ write_seqlock(&vnode->cb_lock);
+ __afs_break_callback(vnode, reason);
+ write_sequnlock(&vnode->cb_lock);
+}
+
+/*
+ * Look up a volume by volume ID under RCU conditions.
+ */
+static struct afs_volume *afs_lookup_volume_rcu(struct afs_cell *cell,
+ afs_volid_t vid)
+{
+ struct afs_volume *volume = NULL;
+ struct rb_node *p;
+ int seq = 0;
+
+ do {
+ /* Unfortunately, rbtree walking doesn't give reliable results
+ * under just the RCU read lock, so we have to check for
+ * changes.
+ */
+ read_seqbegin_or_lock(&cell->volume_lock, &seq);
+
+ p = rcu_dereference_raw(cell->volumes.rb_node);
+ while (p) {
+ volume = rb_entry(p, struct afs_volume, cell_node);
+
+ if (volume->vid < vid)
+ p = rcu_dereference_raw(p->rb_left);
+ else if (volume->vid > vid)
+ p = rcu_dereference_raw(p->rb_right);
+ else
+ break;
+ volume = NULL;
+ }
+
+ } while (need_seqretry(&cell->volume_lock, seq));
+
+ done_seqretry(&cell->volume_lock, seq);
+ return volume;
+}
+
+/*
+ * allow the fileserver to explicitly break one callback
+ * - happens when
+ * - the backing file is changed
+ * - a lock is released
+ */
+static void afs_break_one_callback(struct afs_volume *volume,
+ struct afs_fid *fid)
+{
+ struct super_block *sb;
+ struct afs_vnode *vnode;
+ struct inode *inode;
+
+ if (fid->vnode == 0 && fid->unique == 0) {
+ /* The callback break applies to an entire volume. */
+ write_lock(&volume->cb_v_break_lock);
+ volume->cb_v_break++;
+ trace_afs_cb_break(fid, volume->cb_v_break,
+ afs_cb_break_for_volume_callback, false);
+ write_unlock(&volume->cb_v_break_lock);
+ return;
+ }
+
+ /* See if we can find a matching inode - even an I_NEW inode needs to
+ * be marked as it can have its callback broken before we finish
+ * setting up the local inode.
+ */
+ sb = rcu_dereference(volume->sb);
+ if (!sb)
+ return;
+
+ inode = find_inode_rcu(sb, fid->vnode, afs_ilookup5_test_by_fid, fid);
+ if (inode) {
+ vnode = AFS_FS_I(inode);
+ afs_break_callback(vnode, afs_cb_break_for_callback);
+ } else {
+ trace_afs_cb_miss(fid, afs_cb_break_for_callback);
+ }
+}
+
+static void afs_break_some_callbacks(struct afs_server *server,
+ struct afs_callback_break *cbb,
+ size_t *_count)
+{
+ struct afs_callback_break *residue = cbb;
+ struct afs_volume *volume;
+ afs_volid_t vid = cbb->fid.vid;
+ size_t i;
+
+ volume = afs_lookup_volume_rcu(server->cell, vid);
+
+ /* TODO: Find all matching volumes if we couldn't match the server and
+ * break them anyway.
+ */
+
+ for (i = *_count; i > 0; cbb++, i--) {
+ if (cbb->fid.vid == vid) {
+ _debug("- Fid { vl=%08llx n=%llu u=%u }",
+ cbb->fid.vid,
+ cbb->fid.vnode,
+ cbb->fid.unique);
+ --*_count;
+ if (volume)
+ afs_break_one_callback(volume, &cbb->fid);
+ } else {
+ *residue++ = *cbb;
+ }
+ }
+}
+
+/*
+ * allow the fileserver to break callback promises
+ */
+void afs_break_callbacks(struct afs_server *server, size_t count,
+ struct afs_callback_break *callbacks)
+{
+ _enter("%p,%zu,", server, count);
+
+ ASSERT(server != NULL);
+
+ rcu_read_lock();
+
+ while (count > 0)
+ afs_break_some_callbacks(server, callbacks, &count);
+
+ rcu_read_unlock();
+ return;
+}