Split the global taskqueue used to process all UFS trim completions,

into per-mount taskqueue with the private taskqueue processing thread.
This allows to drain the taskqueue on unmount, to ensure that all
TRIMs are finished before mount structures are freed.

But just draining the taskqueue where TRIM biodone geom-up completions
are processed is not enough, since ffs_blkfree(), called by the task,
might result in more writes.  Count inflight delayed blkfree's and
pause() unmount until the counter drains as well.

Reported by:	Nick Evans <nevans@talkpoint.com>
Tested by:	Nick Evans <nevans@talkpoint.com>, pho
Sponsored by:	The FreeBSD Foundation
MFC after:	2 weeks

2 files changed, 16 insertions, 3 deletions

diff --git a/sys/ufs/ffs/ffs_alloc.c b/sys/ufs/ffs/ffs_alloc.c
index 19c00de..799efe3 100644
--- a/sys/ufs/ffs/ffs_alloc.c
+++ b/sys/ufs/ffs/ffs_alloc.c
@@ -2270,8 +2270,6 @@ ffs_blkfree_cg(ump, fs, devvp, bno, size, inum, dephd)
 	bdwrite(bp);
 }
 
-TASKQUEUE_DEFINE_THREAD(ffs_trim);
-
 struct ffs_blkfree_trim_params {
 	struct task task;
 	struct ufsmount *ump;
@@ -2294,6 +2292,7 @@ ffs_blkfree_trim_task(ctx, pending)
 	ffs_blkfree_cg(tp->ump, tp->ump->um_fs, tp->devvp, tp->bno, tp->size,
 	    tp->inum, tp->pdephd);
 	vn_finished_secondary_write(UFSTOVFS(tp->ump));
+	atomic_add_int(&tp->ump->um_trim_inflight, -1);
 	free(tp, M_TEMP);
 }
 
@@ -2306,7 +2305,7 @@ ffs_blkfree_trim_completed(bip)
 	tp = bip->bio_caller2;
 	g_destroy_bio(bip);
 	TASK_INIT(&tp->task, 0, ffs_blkfree_trim_task, tp);
-	taskqueue_enqueue(taskqueue_ffs_trim, &tp->task);
+	taskqueue_enqueue(tp->ump->um_trim_tq, &tp->task);
 }
 
 void
@@ -2350,6 +2349,7 @@ ffs_blkfree(ump, fs, devvp, bno, size, inum, vtype, dephd)
 	 * reordering, TRIM might be issued after we reuse the block
 	 * and write some new data into it.
 	 */
+	atomic_add_int(&ump->um_trim_inflight, 1);
 	tp = malloc(sizeof(struct ffs_blkfree_trim_params), M_TEMP, M_WAITOK);
 	tp->ump = ump;
 	tp->devvp = devvp;
diff --git a/sys/ufs/ffs/ffs_vfsops.c b/sys/ufs/ffs/ffs_vfsops.c
index a82ef61..b89dc33 100644
--- a/sys/ufs/ffs/ffs_vfsops.c
+++ b/sys/ufs/ffs/ffs_vfsops.c
@@ -42,6 +42,7 @@ __FBSDID("$FreeBSD$");
 #include <sys/namei.h>
 #include <sys/priv.h>
 #include <sys/proc.h>
+#include <sys/taskqueue.h>
 #include <sys/kernel.h>
 #include <sys/vnode.h>
 #include <sys/mount.h>
@@ -1005,6 +1006,12 @@ ffs_mountfs(devvp, mp, td)
 			    mp->mnt_stat.f_mntonname);
 			ump->um_candelete = 0;
 		}
+		if (ump->um_candelete) {
+			ump->um_trim_tq = taskqueue_create("trim", M_WAITOK,
+			    taskqueue_thread_enqueue, &ump->um_trim_tq);
+			taskqueue_start_threads(&ump->um_trim_tq, 1, PVFS,
+			    "%s trim", mp->mnt_stat.f_mntonname);
+		}
 	}
 
 	ump->um_mountp = mp;
@@ -1260,6 +1267,12 @@ ffs_unmount(mp, mntflags)
 	}
 	if (susp)
 		vfs_write_resume(mp, VR_START_WRITE);
+	if (ump->um_trim_tq != NULL) {
+		while (ump->um_trim_inflight != 0)
+			pause("ufsutr", hz);
+		taskqueue_drain_all(ump->um_trim_tq);
+		taskqueue_free(ump->um_trim_tq);
+	}
 	DROP_GIANT();
 	g_topology_lock();
 	if (ump->um_fsckpid > 0) {