From mboxrd@z Thu Jan 1 00:00:00 1970 From: Bob Peterson Date: Mon, 9 Jul 2018 12:50:20 -0500 Subject: [Cluster-devel] [GFS2 PATCH 04/12] GFS2: Add do_xmote states to state machine In-Reply-To: <20180709175028.17090-1-rpeterso@redhat.com> References: <20180709175028.17090-1-rpeterso@redhat.com> Message-ID: <20180709175028.17090-5-rpeterso@redhat.com> List-Id: To: cluster-devel.redhat.com MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit 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 --- 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