ceph: clean up mds reply, error handling
We would occasionally BUG out in the reply handler because r_reply was
nonzero, due to a race with ceph_mdsc_do_request temporarily setting
r_reply to an ERR_PTR value. This is unnecessary, messy, and also wrong
in the EIO case.
Clean up by consistently using r_err for errors and r_reply for messages.
Also fix the abort logic to trigger consistently for all errors that return
to the caller early (e.g., EIO from timeout case). If an abort races with
a reply, use the result from the reply.
Also fix locking for r_err, r_reply update in the reply handler.
Signed-off-by: Sage Weil <sage@newdream.net>
diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c
index 24561a5..b3b19f0 100644
--- a/fs/ceph/mds_client.c
+++ b/fs/ceph/mds_client.c
@@ -1517,7 +1517,7 @@
}
msg = create_request_message(mdsc, req, mds);
if (IS_ERR(msg)) {
- req->r_reply = ERR_PTR(PTR_ERR(msg));
+ req->r_err = PTR_ERR(msg);
complete_request(mdsc, req);
return -PTR_ERR(msg);
}
@@ -1552,7 +1552,7 @@
int mds = -1;
int err = -EAGAIN;
- if (req->r_reply)
+ if (req->r_err || req->r_got_result)
goto out;
if (req->r_timeout &&
@@ -1609,7 +1609,7 @@
return err;
finish:
- req->r_reply = ERR_PTR(err);
+ req->r_err = err;
complete_request(mdsc, req);
goto out;
}
@@ -1689,59 +1689,53 @@
__register_request(mdsc, req, dir);
__do_request(mdsc, req);
- /* wait */
- if (!req->r_reply) {
- mutex_unlock(&mdsc->mutex);
- if (req->r_timeout) {
- err = (long)wait_for_completion_interruptible_timeout(
- &req->r_completion, req->r_timeout);
- if (err == 0)
- req->r_reply = ERR_PTR(-EIO);
- else if (err < 0)
- req->r_reply = ERR_PTR(err);
- } else {
- err = wait_for_completion_interruptible(
- &req->r_completion);
- if (err)
- req->r_reply = ERR_PTR(err);
- }
- mutex_lock(&mdsc->mutex);
- }
-
- if (IS_ERR(req->r_reply)) {
- err = PTR_ERR(req->r_reply);
- req->r_reply = NULL;
-
- if (err == -ERESTARTSYS) {
- /* aborted */
- req->r_aborted = true;
-
- if (req->r_locked_dir &&
- (req->r_op & CEPH_MDS_OP_WRITE)) {
- struct ceph_inode_info *ci =
- ceph_inode(req->r_locked_dir);
-
- dout("aborted, clearing I_COMPLETE on %p\n",
- req->r_locked_dir);
- spin_lock(&req->r_locked_dir->i_lock);
- ci->i_ceph_flags &= ~CEPH_I_COMPLETE;
- ci->i_release_count++;
- spin_unlock(&req->r_locked_dir->i_lock);
- }
- } else {
- /* clean up this request */
- __unregister_request(mdsc, req);
- if (!list_empty(&req->r_unsafe_item))
- list_del_init(&req->r_unsafe_item);
- complete(&req->r_safe_completion);
- }
- } else if (req->r_err) {
+ if (req->r_err) {
err = req->r_err;
- } else {
- err = le32_to_cpu(req->r_reply_info.head->result);
+ __unregister_request(mdsc, req);
+ dout("do_request early error %d\n", err);
+ goto out;
}
- mutex_unlock(&mdsc->mutex);
+ /* wait */
+ mutex_unlock(&mdsc->mutex);
+ dout("do_request waiting\n");
+ if (req->r_timeout) {
+ err = (long)wait_for_completion_interruptible_timeout(
+ &req->r_completion, req->r_timeout);
+ if (err == 0)
+ err = -EIO;
+ } else {
+ err = wait_for_completion_interruptible(&req->r_completion);
+ }
+ dout("do_request waited, got %d\n", err);
+ mutex_lock(&mdsc->mutex);
+
+ /* only abort if we didn't race with a real reply */
+ if (req->r_got_result) {
+ err = le32_to_cpu(req->r_reply_info.head->result);
+ } else if (err < 0) {
+ dout("aborted request %lld with %d\n", req->r_tid, err);
+ req->r_err = err;
+ req->r_aborted = true;
+
+ if (req->r_locked_dir &&
+ (req->r_op & CEPH_MDS_OP_WRITE)) {
+ struct ceph_inode_info *ci =
+ ceph_inode(req->r_locked_dir);
+
+ dout("aborted, clearing I_COMPLETE on %p\n",
+ req->r_locked_dir);
+ spin_lock(&req->r_locked_dir->i_lock);
+ ci->i_ceph_flags &= ~CEPH_I_COMPLETE;
+ ci->i_release_count++;
+ spin_unlock(&req->r_locked_dir->i_lock);
+ }
+ } else {
+ err = req->r_err;
+ }
+
+out:
+ mutex_unlock(&mdsc->mutex);
dout("do_request %p done, result %d\n", req, err);
return err;
}
@@ -1838,11 +1832,7 @@
mutex_unlock(&mdsc->mutex);
goto out;
}
- }
-
- BUG_ON(req->r_reply);
-
- if (!head->safe) {
+ } else {
req->r_got_unsafe = true;
list_add_tail(&req->r_unsafe_item, &req->r_session->s_unsafe);
}
@@ -1880,12 +1870,19 @@
up_read(&mdsc->snap_rwsem);
out_err:
- if (err) {
- req->r_err = err;
+ mutex_lock(&mdsc->mutex);
+ if (!req->r_aborted) {
+ if (err) {
+ req->r_err = err;
+ } else {
+ req->r_reply = msg;
+ ceph_msg_get(msg);
+ req->r_got_result = true;
+ }
} else {
- req->r_reply = msg;
- ceph_msg_get(msg);
+ dout("reply arrived after request %lld was aborted\n", tid);
}
+ mutex_unlock(&mdsc->mutex);
add_cap_releases(mdsc, req->r_session, -1);
mutex_unlock(&session->s_mutex);
