1 files changed, 112 insertions, 25 deletions

diff --git a/fs/gfs2/glock.c b/fs/gfs2/glock.c
index d0eceaff3cea..29f9b6684b74 100644
--- a/fs/gfs2/glock.c
+++ b/fs/gfs2/glock.c
@@ -133,6 +133,33 @@ static void gfs2_glock_dealloc(struct rcu_head *rcu)
 	}
 }
 
+/**
+ * glock_blocked_by_withdraw - determine if we can still use a glock
+ * @gl: the glock
+ *
+ * We need to allow some glocks to be enqueued, dequeued, promoted, and demoted
+ * when we're withdrawn. For example, to maintain metadata integrity, we should
+ * disallow the use of inode and rgrp glocks when withdrawn. Other glocks, like
+ * iopen or the transaction glocks may be safely used because none of their
+ * metadata goes through the journal. So in general, we should disallow all
+ * glocks that are journaled, and allow all the others. One exception is:
+ * we need to allow our active journal to be promoted and demoted so others
+ * may recover it and we can reacquire it when they're done.
+ */
+static bool glock_blocked_by_withdraw(struct gfs2_glock *gl)
+{
+	struct gfs2_sbd *sdp = gl->gl_name.ln_sbd;
+
+	if (likely(!gfs2_withdrawn(sdp)))
+		return false;
+	if (gl->gl_ops->go_flags & GLOF_NONDISK)
+		return false;
+	if (!sdp->sd_jdesc ||
+	    gl->gl_name.ln_number == sdp->sd_jdesc->jd_no_addr)
+		return false;
+	return true;
+}
+
 void gfs2_glock_free(struct gfs2_glock *gl)
 {
 	struct gfs2_sbd *sdp = gl->gl_name.ln_sbd;
@@ -244,7 +271,7 @@ static void __gfs2_glock_put(struct gfs2_glock *gl)
 	gfs2_glock_remove_from_lru(gl);
 	spin_unlock(&gl->gl_lockref.lock);
 	GLOCK_BUG_ON(gl, !list_empty(&gl->gl_holders));
-	GLOCK_BUG_ON(gl, mapping && mapping->nrpages);
+	GLOCK_BUG_ON(gl, mapping && mapping->nrpages && !gfs2_withdrawn(sdp));
 	trace_gfs2_glock_put(gl);
 	sdp->sd_lockstruct.ls_ops->lm_put_lock(gl);
 }
@@ -281,7 +308,7 @@ void gfs2_glock_put(struct gfs2_glock *gl)
 
 static inline int may_grant(const struct gfs2_glock *gl, const struct gfs2_holder *gh)
 {
-	const struct gfs2_holder *gh_head = list_entry(gl->gl_holders.next, const struct gfs2_holder, gh_list);
+	const struct gfs2_holder *gh_head = list_first_entry(&gl->gl_holders, const struct gfs2_holder, gh_list);
 	if ((gh->gh_state == LM_ST_EXCLUSIVE ||
 	     gh_head->gh_state == LM_ST_EXCLUSIVE) && gh != gh_head)
 		return 0;
@@ -549,8 +576,8 @@ __acquires(&gl->gl_lockref.lock)
 	unsigned int lck_flags = (unsigned int)(gh ? gh->gh_flags : 0);
 	int ret;
 
-	if (unlikely(gfs2_withdrawn(sdp)) &&
-	    target != LM_ST_UNLOCKED)
+	if (target != LM_ST_UNLOCKED && glock_blocked_by_withdraw(gl) &&
+	    gh && !(gh->gh_flags & LM_FLAG_NOEXP))
 		return;
 	lck_flags &= (LM_FLAG_TRY | LM_FLAG_TRY_1CB | LM_FLAG_NOEXP |
 		      LM_FLAG_PRIORITY);
@@ -575,13 +602,64 @@ __acquires(&gl->gl_lockref.lock)
 	    (lck_flags & (LM_FLAG_TRY|LM_FLAG_TRY_1CB)))
 		clear_bit(GLF_BLOCKING, &gl->gl_flags);
 	spin_unlock(&gl->gl_lockref.lock);
-	if (glops->go_sync)
-		glops->go_sync(gl);
-	if (test_bit(GLF_INVALIDATE_IN_PROGRESS, &gl->gl_flags))
+	if (glops->go_sync) {
+		ret = glops->go_sync(gl);
+		/* If we had a problem syncing (due to io errors or whatever,
+		 * we should not invalidate the metadata or tell dlm to
+		 * release the glock to other nodes.
+		 */
+		if (ret) {
+			if (cmpxchg(&sdp->sd_log_error, 0, ret)) {
+				fs_err(sdp, "Error %d syncing glock \n", ret);
+				gfs2_dump_glock(NULL, gl, true);
+			}
+			return;
+		}
+	}
+	if (test_bit(GLF_INVALIDATE_IN_PROGRESS, &gl->gl_flags)) {
+		/*
+		 * The call to go_sync should have cleared out the ail list.
+		 * If there are still items, we have a problem. We ought to
+		 * withdraw, but we can't because the withdraw code also uses
+		 * glocks. Warn about the error, dump the glock, then fall
+		 * through and wait for logd to do the withdraw for us.
+		 */
+		if ((atomic_read(&gl->gl_ail_count) != 0) &&
+		    (!cmpxchg(&sdp->sd_log_error, 0, -EIO))) {
+			gfs2_assert_warn(sdp, !atomic_read(&gl->gl_ail_count));
+			gfs2_dump_glock(NULL, gl, true);
+		}
 		glops->go_inval(gl, target == LM_ST_DEFERRED ? 0 : DIO_METADATA);
-	clear_bit(GLF_INVALIDATE_IN_PROGRESS, &gl->gl_flags);
+		clear_bit(GLF_INVALIDATE_IN_PROGRESS, &gl->gl_flags);
+	}
 
 	gfs2_glock_hold(gl);
+	/*
+	 * Check for an error encountered since we called go_sync and go_inval.
+	 * If so, we can't withdraw from the glock code because the withdraw
+	 * code itself uses glocks (see function signal_our_withdraw) to
+	 * change the mount to read-only. Most importantly, we must not call
+	 * dlm to unlock the glock until the journal is in a known good state
+	 * (after journal replay) otherwise other nodes may use the object
+	 * (rgrp or dinode) and then later, journal replay will corrupt the
+	 * file system. The best we can do here is wait for the logd daemon
+	 * to see sd_log_error and withdraw, and in the meantime, requeue the
+	 * work for later.
+	 *
+	 * However, if we're just unlocking the lock (say, for unmount, when
+	 * gfs2_gl_hash_clear calls clear_glock) and recovery is complete
+	 * then it's okay to tell dlm to unlock it.
+	 */
+	if (unlikely(sdp->sd_log_error && !gfs2_withdrawn(sdp)))
+		gfs2_withdraw_delayed(sdp);
+	if (glock_blocked_by_withdraw(gl)) {
+		if (target != LM_ST_UNLOCKED ||
+		    test_bit(SDF_WITHDRAW_RECOVERY, &sdp->sd_flags)) {
+			gfs2_glock_queue_work(gl, GL_GLOCK_DFT_HOLD);
+			goto out;
+		}
+	}
+
 	if (sdp->sd_lockstruct.ls_ops->lm_lock)	{
 		/* lock_dlm */
 		ret = sdp->sd_lockstruct.ls_ops->lm_lock(gl, target, lck_flags);
@@ -590,8 +668,7 @@ __acquires(&gl->gl_lockref.lock)
 		    test_bit(SDF_SKIP_DLM_UNLOCK, &sdp->sd_flags)) {
 			finish_xmote(gl, target);
 			gfs2_glock_queue_work(gl, 0);
-		}
-		else if (ret) {
+		} else if (ret) {
 			fs_err(sdp, "lm_lock ret %d\n", ret);
 			GLOCK_BUG_ON(gl, !gfs2_withdrawn(sdp));
 		}
@@ -599,7 +676,7 @@ __acquires(&gl->gl_lockref.lock)
 		finish_xmote(gl, target);
 		gfs2_glock_queue_work(gl, 0);
 	}
-
+out:
 	spin_lock(&gl->gl_lockref.lock);
 }
 
@@ -613,7 +690,7 @@ static inline struct gfs2_holder *find_first_holder(const struct gfs2_glock *gl)
 	struct gfs2_holder *gh;
 
 	if (!list_empty(&gl->gl_holders)) {
-		gh = list_entry(gl->gl_holders.next, struct gfs2_holder, gh_list);
+		gh = list_first_entry(&gl->gl_holders, struct gfs2_holder, gh_list);
 		if (test_bit(HIF_HOLDER, &gh->gh_iflags))
 			return gh;
 	}
@@ -645,6 +722,9 @@ __acquires(&gl->gl_lockref.lock)
 			goto out_unlock;
 		if (nonblock)
 			goto out_sched;
+		smp_mb();
+		if (atomic_read(&gl->gl_revokes) != 0)
+			goto out_sched;
 		set_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags);
 		GLOCK_BUG_ON(gl, gl->gl_demote_state == LM_ST_EXCLUSIVE);
 		gl->gl_target = gl->gl_demote_state;
@@ -1160,7 +1240,7 @@ fail:
 	}
 	list_add_tail(&gh->gh_list, insert_pt);
 do_cancel:
-	gh = list_entry(gl->gl_holders.next, struct gfs2_holder, gh_list);
+	gh = list_first_entry(&gl->gl_holders, struct gfs2_holder, gh_list);
 	if (!(gh->gh_flags & LM_FLAG_PRIORITY)) {
 		spin_unlock(&gl->gl_lockref.lock);
 		if (sdp->sd_lockstruct.ls_ops->lm_cancel)
@@ -1194,10 +1274,9 @@ trap_recursive:
 int gfs2_glock_nq(struct gfs2_holder *gh)
 {
 	struct gfs2_glock *gl = gh->gh_gl;
-	struct gfs2_sbd *sdp = gl->gl_name.ln_sbd;
 	int error = 0;
 
-	if (unlikely(gfs2_withdrawn(sdp)))
+	if (glock_blocked_by_withdraw(gl) && !(gh->gh_flags & LM_FLAG_NOEXP))
 		return -EIO;
 
 	if (test_bit(GLF_LRU, &gl->gl_flags))
@@ -1241,24 +1320,32 @@ int gfs2_glock_poll(struct gfs2_holder *gh)
 void gfs2_glock_dq(struct gfs2_holder *gh)
 {
 	struct gfs2_glock *gl = gh->gh_gl;
-	const struct gfs2_glock_operations *glops = gl->gl_ops;
+	struct gfs2_sbd *sdp = gl->gl_name.ln_sbd;
 	unsigned delay = 0;
 	int fast_path = 0;
 
 	spin_lock(&gl->gl_lockref.lock);
+	/*
+	 * If we're in the process of file system withdraw, we cannot just
+	 * dequeue any glocks until our journal is recovered, lest we
+	 * introduce file system corruption. We need two exceptions to this
+	 * rule: We need to allow unlocking of nondisk glocks and the glock
+	 * for our own journal that needs recovery.
+	 */
+	if (test_bit(SDF_WITHDRAW_RECOVERY, &sdp->sd_flags) &&
+	    glock_blocked_by_withdraw(gl) &&
+	    gh->gh_gl != sdp->sd_jinode_gl) {
+		sdp->sd_glock_dqs_held++;
+		might_sleep();
+		wait_on_bit(&sdp->sd_flags, SDF_WITHDRAW_RECOVERY,
+			    TASK_UNINTERRUPTIBLE);
+	}
 	if (gh->gh_flags & GL_NOCACHE)
 		handle_callback(gl, LM_ST_UNLOCKED, 0, false);
 
 	list_del_init(&gh->gh_list);
 	clear_bit(HIF_HOLDER, &gh->gh_iflags);
 	if (find_first_holder(gl) == NULL) {
-		if (glops->go_unlock) {
-			GLOCK_BUG_ON(gl, test_and_set_bit(GLF_LOCK, &gl->gl_flags));
-			spin_unlock(&gl->gl_lockref.lock);
-			glops->go_unlock(gh);
-			spin_lock(&gl->gl_lockref.lock);
-			clear_bit(GLF_LOCK, &gl->gl_flags);
-		}
 		if (list_empty(&gl->gl_holders) &&
 		    !test_bit(GLF_PENDING_DEMOTE, &gl->gl_flags) &&
 		    !test_bit(GLF_DEMOTE, &gl->gl_flags))
@@ -1555,7 +1642,7 @@ __acquires(&lru_lock)
 	list_sort(NULL, list, glock_cmp);
 
 	while(!list_empty(list)) {
-		gl = list_entry(list->next, struct gfs2_glock, gl_lru);
+		gl = list_first_entry(list, struct gfs2_glock, gl_lru);
 		list_del_init(&gl->gl_lru);
 		if (!spin_trylock(&gl->gl_lockref.lock)) {
 add_back_to_lru:
@@ -1596,7 +1683,7 @@ static long gfs2_scan_glock_lru(int nr)
 
 	spin_lock(&lru_lock);
 	while ((nr-- >= 0) && !list_empty(&lru_list)) {
-		gl = list_entry(lru_list.next, struct gfs2_glock, gl_lru);
+		gl = list_first_entry(&lru_list, struct gfs2_glock, gl_lru);
 
 		/* Test for being demotable */
 		if (!test_bit(GLF_LOCK, &gl->gl_flags)) {