From: Bob Peterson <rpeterso@redhat.com>
To: cluster-devel.redhat.com
Subject: [Cluster-devel] [GFS2 PATCH 04/12] GFS2: Add do_xmote states to state machine
Date: Mon, 9 Jul 2018 12:50:20 -0500 [thread overview]
Message-ID: <20180709175028.17090-5-rpeterso@redhat.com> (raw)
In-Reply-To: <20180709175028.17090-1-rpeterso@redhat.com>
This patch adds two new states to the glock state machine. The
first is a normal call for gl_target. The second is an abnormal
call for cases in which dlm was unable to grant our request.
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
---
fs/gfs2/glock.c | 37 ++++++++++++++++++++++++++++---------
fs/gfs2/glock.h | 3 +++
2 files changed, 31 insertions(+), 9 deletions(-)
diff --git a/fs/gfs2/glock.c b/fs/gfs2/glock.c
index b5ba0abca51f..b87c51479a8a 100644
--- a/fs/gfs2/glock.c
+++ b/fs/gfs2/glock.c
@@ -60,7 +60,7 @@ struct gfs2_glock_iter {
typedef void (*glock_examiner) (struct gfs2_glock * gl);
-static void do_xmote(struct gfs2_glock *gl, unsigned int target);
+static void __state_machine(struct gfs2_glock *gl, int new_state);
static void state_machine(struct gfs2_glock *gl, int new_state);
static struct dentry *gfs2_root;
@@ -444,9 +444,12 @@ static void gfs2_demote_wake(struct gfs2_glock *gl)
* finish_xmote - The DLM has replied to one of our lock requests
* @gl: The glock
*
+ * Returns: -EAGAIN if do_xmote should be called next
+ * -EBUSY if dlm could not satisfy the request
+ * else 0
*/
-static void finish_xmote(struct gfs2_glock *gl)
+static int finish_xmote(struct gfs2_glock *gl)
{
const struct gfs2_glock_operations *glops = gl->gl_ops;
struct gfs2_holder *gh;
@@ -484,18 +487,16 @@ static void finish_xmote(struct gfs2_glock *gl)
switch(state) {
/* Unlocked due to conversion deadlock, try again */
case LM_ST_UNLOCKED:
- do_xmote(gl, gl->gl_target);
- break;
+ return -EAGAIN;
/* Conversion fails, unlock and try again */
case LM_ST_SHARED:
case LM_ST_DEFERRED:
- do_xmote(gl, LM_ST_UNLOCKED);
- break;
+ return -EBUSY;
default: /* Everything else */
pr_err("wanted %u got %u\n", gl->gl_target, state);
GLOCK_BUG_ON(gl, 1);
}
- return;
+ return 0;
}
/* Fast path - we got what we asked for */
@@ -513,10 +514,11 @@ static void finish_xmote(struct gfs2_glock *gl)
}
rv = do_promote(gl);
if (rv == 2)
- return;
+ return 0;
}
out:
clear_bit(GLF_LOCK, &gl->gl_flags);
+ return 0;
}
/**
@@ -655,7 +657,7 @@ __acquires(&gl->gl_lockref.lock)
if (!(gh->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB)))
do_error(gl, 0); /* Fail queued try locks */
}
- do_xmote(gl, gl->gl_target);
+ __state_machine(gl, GL_ST_DO_XMOTE);
return;
}
@@ -673,6 +675,8 @@ __acquires(&gl->gl_lockref.lock)
*/
static void __state_machine(struct gfs2_glock *gl, int new_state)
{
+ int ret;
+
BUG_ON(!spin_is_locked(&gl->gl_lockref.lock));
do {
@@ -684,6 +688,21 @@ static void __state_machine(struct gfs2_glock *gl, int new_state)
case GL_ST_FINISH_XMOTE:
gl->gl_mch = GL_ST_IDLE;
+ ret = finish_xmote(gl);
+ if (ret == -EBUSY)
+ gl->gl_mch = GL_ST_DO_XMOTE_UNLOCK;
+ else if (ret == -EAGAIN)
+ gl->gl_mch = GL_ST_DO_XMOTE;
+ break;
+
+ case GL_ST_DO_XMOTE:
+ gl->gl_mch = GL_ST_IDLE;
+ do_xmote(gl, gl->gl_target);
+ break;
+
+ case GL_ST_DO_XMOTE_UNLOCK:
+ gl->gl_mch = GL_ST_IDLE;
+ do_xmote(gl, LM_ST_UNLOCKED);
finish_xmote(gl);
break;
}
diff --git a/fs/gfs2/glock.h b/fs/gfs2/glock.h
index 88043d610d64..8333bbc5a197 100644
--- a/fs/gfs2/glock.h
+++ b/fs/gfs2/glock.h
@@ -123,6 +123,9 @@ enum {
enum gl_machine_states {
GL_ST_IDLE = 0, /* State machine idle; no transition needed */
GL_ST_FINISH_XMOTE = 1, /* Promotion/demotion complete */
+ GL_ST_DO_XMOTE = 2, /* Promote or demote a waiter */
+ GL_ST_DO_XMOTE_UNLOCK = 3, /* Promote or demote a waiter after a failed
+ state change attempt from dlm. */
};
struct lm_lockops {
--
2.17.1
next prev parent reply other threads:[~2018-07-09 17:50 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-07-09 17:50 [Cluster-devel] [GFS2 PATCH 00/12] Radical Reform of glock state machine Bob Peterson
2018-07-09 17:50 ` [Cluster-devel] [GFS2 PATCH 01/12] GFS2: Make do_xmote determine its own gh parameter Bob Peterson
2018-07-09 17:50 ` [Cluster-devel] [GFS2 PATCH 02/12] GFS2: Eliminate a goto in finish_xmote Bob Peterson
2018-07-09 17:50 ` [Cluster-devel] [GFS2 PATCH 03/12] GFS2: Baby step toward a real state machine: finish_xmote Bob Peterson
2018-07-09 17:50 ` Bob Peterson [this message]
2018-07-09 17:50 ` [Cluster-devel] [GFS2 PATCH 05/12] GFS2: Make do_xmote not call the state machine again Bob Peterson
2018-07-09 17:50 ` [Cluster-devel] [GFS2 PATCH 06/12] GFS2: Add blocking and non-blocking demote to state machine Bob Peterson
2018-07-09 17:50 ` [Cluster-devel] [GFS2 PATCH 07/12] GFS2: Add a new GL_ST_PROMOTE state to glock " Bob Peterson
2018-07-09 17:50 ` [Cluster-devel] [GFS2 PATCH 08/12] GFS2: Replace run_queue with new GL_ST_RUN state in " Bob Peterson
2018-07-09 17:50 ` [Cluster-devel] [GFS2 PATCH 09/12] GFS2: Reduce redundancy in GL_ST_DEMOTE_NONBLOCK state Bob Peterson
2018-07-09 17:50 ` [Cluster-devel] [GFS2 PATCH 10/12] GFS2: Reduce glock_work_func to a single call to state_machine Bob Peterson
2018-07-09 17:50 ` [Cluster-devel] [GFS2 PATCH 11/12] GFS2: Add new GL_ST_UNLOCK state to reduce calls to the __ version Bob Peterson
2018-07-09 17:50 ` [Cluster-devel] [GFS2 PATCH 12/12] GFS2: Optimization of GL_ST_UNLOCK state Bob Peterson
2018-07-10 8:27 ` [Cluster-devel] [GFS2 PATCH 00/12] Radical Reform of glock state machine Steven Whitehouse
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20180709175028.17090-5-rpeterso@redhat.com \
--to=rpeterso@redhat.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).