afs: Calculate lock extend timer from set/extend reply reception

Record the timestamp on the first reply DATA packet received in response to
a set- or extend-lock operation, then use this to calculate the time
remaining till the lock expires rather than using whatever time the
requesting process wakes up and finishes processing the operation as a
base.

Signed-off-by: David Howells <dhowells@redhat.com>

4 files changed, 38 insertions, 2 deletions

diff --git a/fs/afs/flock.c b/fs/afs/flock.c
index e432bd27a2e7..8b02f0056d54 100644
--- a/fs/afs/flock.c
+++ b/fs/afs/flock.c
@@ -40,8 +40,34 @@ void afs_lock_may_be_available(struct afs_vnode *vnode)
  */
 static void afs_schedule_lock_extension(struct afs_vnode *vnode)
 {
-        queue_delayed_work(afs_lock_manager, &vnode->lock_work,
-                           AFS_LOCKWAIT * HZ / 2);
+        ktime_t expires_at, now, duration;
+        u64 duration_j;
+
+        expires_at = ktime_add_ms(vnode->locked_at, AFS_LOCKWAIT * 1000 / 2);
+        now = ktime_get_real();
+        duration = ktime_sub(expires_at, now);
+        if (duration <= 0)
+                duration_j = 0;
+        else
+                duration_j = nsecs_to_jiffies(ktime_to_ns(duration));
+
+        queue_delayed_work(afs_lock_manager, &vnode->lock_work, duration_j);
+}
+
+/*
+ * In the case of successful completion of a lock operation, record the time
+ * the reply appeared and start the lock extension timer.
+ */
+void afs_lock_op_done(struct afs_call *call)
+{
+        struct afs_vnode *vnode = call->reply[0];
+
+        if (call->error == 0) {
+                spin_lock(&vnode->lock);
+                vnode->locked_at = call->reply_time;
+                afs_schedule_lock_extension(vnode);
+                spin_unlock(&vnode->lock);
+        }
 }
 
 /*
diff --git a/fs/afs/fsclient.c b/fs/afs/fsclient.c
index 5eefcf35d73d..9d405f96cc91 100644
--- a/fs/afs/fsclient.c
+++ b/fs/afs/fsclient.c
@@ -1845,6 +1845,7 @@ static const struct afs_call_type afs_RXFSSetLock = {
         .name           = "FS.SetLock",
         .op             = afs_FS_SetLock,
         .deliver        = afs_deliver_fs_xxxx_lock,
+        .done           = afs_lock_op_done,
         .destructor     = afs_flat_call_destructor,
 };
 
@@ -1855,6 +1856,7 @@ static const struct afs_call_type afs_RXFSExtendLock = {
         .name           = "FS.ExtendLock",
         .op             = afs_FS_ExtendLock,
         .deliver        = afs_deliver_fs_xxxx_lock,
+        .done           = afs_lock_op_done,
         .destructor     = afs_flat_call_destructor,
 };
 
@@ -1889,6 +1891,7 @@ int afs_fs_set_lock(struct afs_fs_cursor *fc, afs_lock_type_t type)
 
         call->key = fc->key;
         call->reply[0] = vnode;
+        call->want_reply_time = true;
 
         /* marshall the parameters */
         bp = call->request;
@@ -1925,6 +1928,7 @@ int afs_fs_extend_lock(struct afs_fs_cursor *fc)
 
         call->key = fc->key;
         call->reply[0] = vnode;
+        call->want_reply_time = true;
 
         /* marshall the parameters */
         bp = call->request;
diff --git a/fs/afs/internal.h b/fs/afs/internal.h
index 61e24551574d..6e680783f59f 100644
--- a/fs/afs/internal.h
+++ b/fs/afs/internal.h
@@ -638,6 +638,7 @@ struct afs_vnode {
         struct list_head        granted_locks;  /* locks granted on this file */
         struct delayed_work     lock_work;      /* work to be done in locking */
         struct key              *lock_key;      /* Key to be used in lock ops */
+        ktime_t                 locked_at;      /* Time at which lock obtained */
         enum afs_lock_state     lock_state : 8;
         afs_lock_type_t         lock_type : 8;
 
@@ -905,6 +906,7 @@ extern void afs_put_read(struct afs_read *);
  */
 extern struct workqueue_struct *afs_lock_manager;
 
+extern void afs_lock_op_done(struct afs_call *);
 extern void afs_lock_work(struct work_struct *);
 extern void afs_lock_may_be_available(struct afs_vnode *);
 extern int afs_lock(struct file *, int, struct file_lock *);
diff --git a/fs/afs/yfsclient.c b/fs/afs/yfsclient.c
index 95b04cb76c8c..73546c2d89ee 100644
--- a/fs/afs/yfsclient.c
+++ b/fs/afs/yfsclient.c
@@ -1801,6 +1801,7 @@ static const struct afs_call_type yfs_RXYFSSetLock = {
         .name           = "YFS.SetLock",
         .op             = yfs_FS_SetLock,
         .deliver        = yfs_deliver_fs_xxxx_lock,
+        .done           = afs_lock_op_done,
         .destructor     = afs_flat_call_destructor,
 };
 
@@ -1811,6 +1812,7 @@ static const struct afs_call_type yfs_RXYFSExtendLock = {
         .name           = "YFS.ExtendLock",
         .op             = yfs_FS_ExtendLock,
         .deliver        = yfs_deliver_fs_xxxx_lock,
+        .done           = afs_lock_op_done,
         .destructor     = afs_flat_call_destructor,
 };
 
@@ -1847,6 +1849,7 @@ int yfs_fs_set_lock(struct afs_fs_cursor *fc, afs_lock_type_t type)
 
         call->key = fc->key;
         call->reply[0] = vnode;
+        call->want_reply_time = true;
 
         /* marshall the parameters */
         bp = call->request;
@@ -1884,6 +1887,7 @@ int yfs_fs_extend_lock(struct afs_fs_cursor *fc)
 
         call->key = fc->key;
         call->reply[0] = vnode;
+        call->want_reply_time = true;
 
         /* marshall the parameters */
         bp = call->request;