Add kernel side support for BIO_DELETE/TRIM on UFS.

The FS_TRIM fs flag indicates that administrator requested issuing of
TRIM commands for the volume. UFS will only send the command to disk
if the disk reports GEOM::candelete attribute.

Since disk queue is reordered, data block is marked as free in the bitmap
only after TRIM command completed. Due to need to sleep waiting for
i/o to finish, TRIM bio_done routine schedules taskqueue to set the
bitmap bit.

Based on the patch by:	mckusick
Reviewed by:	mckusick, pjd
Tested by:	pho
MFC after:	1 month

4 files changed, 117 insertions, 2 deletions

diff --git a/sys/ufs/ffs/ffs_alloc.c b/sys/ufs/ffs/ffs_alloc.c
index b740bbb..392c150 100644
--- a/sys/ufs/ffs/ffs_alloc.c
+++ b/sys/ufs/ffs/ffs_alloc.c
@@ -80,9 +80,12 @@ __FBSDID("$FreeBSD$");
 #include <sys/syscallsubr.h>
 #include <sys/sysctl.h>
 #include <sys/syslog.h>
+#include <sys/taskqueue.h>
 
 #include <security/audit/audit.h>
 
+#include <geom/geom.h>
+
 #include <ufs/ufs/dir.h>
 #include <ufs/ufs/extattr.h>
 #include <ufs/ufs/quota.h>
@@ -92,6 +95,7 @@ __FBSDID("$FreeBSD$");
 
 #include <ufs/ffs/fs.h>
 #include <ufs/ffs/ffs_extern.h>
+#include <ufs/ffs/softdep.h>
 
 typedef ufs2_daddr_t allocfcn_t(struct inode *ip, u_int cg, ufs2_daddr_t bpref,
 				  int size, int rsize);
@@ -99,6 +103,11 @@ typedef ufs2_daddr_t allocfcn_t(struct inode *ip, u_int cg, ufs2_daddr_t bpref,
 static ufs2_daddr_t ffs_alloccg(struct inode *, u_int, ufs2_daddr_t, int, int);
 static ufs2_daddr_t
 	      ffs_alloccgblk(struct inode *, struct buf *, ufs2_daddr_t, int);
+static void	ffs_blkfree_cg(struct ufsmount *, struct fs *,
+		    struct vnode *, ufs2_daddr_t, long, ino_t,
+		    struct workhead *);
+static void	ffs_blkfree_trim_completed(struct bio *);
+static void	ffs_blkfree_trim_task(void *ctx, int pending __unused);
 #ifdef INVARIANTS
 static int	ffs_checkblk(struct inode *, ufs2_daddr_t, long);
 #endif
@@ -1831,8 +1840,8 @@ gotit:
  * free map. If a fragment is deallocated, a possible
  * block reassembly is checked.
  */
-void
-ffs_blkfree(ump, fs, devvp, bno, size, inum, dephd)
+static void
+ffs_blkfree_cg(ump, fs, devvp, bno, size, inum, dephd)
 	struct ufsmount *ump;
 	struct fs *fs;
 	struct vnode *devvp;
@@ -1964,6 +1973,95 @@ ffs_blkfree(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;
+	struct vnode *devvp;
+	ufs2_daddr_t bno;
+	long size;
+	ino_t inum;
+	struct workhead *pdephd;
+	struct workhead dephd;
+};
+
+static void
+ffs_blkfree_trim_task(ctx, pending)
+	void *ctx;
+	int pending;
+{
+	struct ffs_blkfree_trim_params *tp;
+
+	tp = ctx;
+	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));
+	free(tp, M_TEMP);
+}
+
+static void
+ffs_blkfree_trim_completed(bip)
+	struct bio *bip;
+{
+	struct ffs_blkfree_trim_params *tp;
+
+	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);
+}
+
+void
+ffs_blkfree(ump, fs, devvp, bno, size, inum, dephd)
+	struct ufsmount *ump;
+	struct fs *fs;
+	struct vnode *devvp;
+	ufs2_daddr_t bno;
+	long size;
+	ino_t inum;
+	struct workhead *dephd;
+{
+	struct mount *mp;
+	struct bio *bip;
+	struct ffs_blkfree_trim_params *tp;
+
+	if (!ump->um_candelete) {
+		ffs_blkfree_cg(ump, fs, devvp, bno, size, inum, dephd);
+		return;
+	}
+
+	/*
+	 * Postpone the set of the free bit in the cg bitmap until the
+	 * BIO_DELETE is completed.  Otherwise, due to disk queue
+	 * reordering, TRIM might be issued after we reuse the block
+	 * and write some new data into it.
+	 */
+	tp = malloc(sizeof(struct ffs_blkfree_trim_params), M_TEMP, M_WAITOK);
+	tp->ump = ump;
+	tp->devvp = devvp;
+	tp->bno = bno;
+	tp->size = size;
+	tp->inum = inum;
+	if (dephd != NULL) {
+		LIST_INIT(&tp->dephd);
+		LIST_SWAP(dephd, &tp->dephd, worklist, wk_list);
+		tp->pdephd = &tp->dephd;
+	} else
+		tp->pdephd = NULL;
+
+	bip = g_alloc_bio();
+	bip->bio_cmd = BIO_DELETE;
+	bip->bio_offset = dbtob(fsbtodb(fs, bno));
+	bip->bio_done = ffs_blkfree_trim_completed;
+	bip->bio_length = size;
+	bip->bio_caller2 = tp;
+
+	mp = UFSTOVFS(ump);
+	vn_start_secondary_write(NULL, &mp, 0);
+	g_io_request(bip, (struct g_consumer *)devvp->v_bufobj.bo_private);
+}
+
 #ifdef INVARIANTS
 /*
  * Verify allocation of a block or fragment. Returns true if block or
diff --git a/sys/ufs/ffs/ffs_vfsops.c b/sys/ufs/ffs/ffs_vfsops.c
index 72f40da..f578382 100644
--- a/sys/ufs/ffs/ffs_vfsops.c
+++ b/sys/ufs/ffs/ffs_vfsops.c
@@ -895,6 +895,21 @@ ffs_mountfs(devvp, mp, td)
 		    mp->mnt_stat.f_mntonname);
 #endif
 	}
+	if ((fs->fs_flags & FS_TRIM) != 0) {
+		size = sizeof(int);
+		if (g_io_getattr("GEOM::candelete", cp, &size,
+		    &ump->um_candelete) == 0) {
+			if (!ump->um_candelete)
+				printf(
+"WARNING: %s: TRIM flag on fs but disk does not support TRIM\n",
+				    mp->mnt_stat.f_mntonname);
+		} else {
+			printf(
+"WARNING: %s: TRIM flag on fs but cannot get whether disk supports TRIM\n",
+			    mp->mnt_stat.f_mntonname);
+			ump->um_candelete = 0;
+		}
+	}
 
 	ump->um_mountp = mp;
 	ump->um_dev = dev;
diff --git a/sys/ufs/ffs/fs.h b/sys/ufs/ffs/fs.h
index ba98ed3..13d9ede 100644
--- a/sys/ufs/ffs/fs.h
+++ b/sys/ufs/ffs/fs.h
@@ -417,6 +417,7 @@ CTASSERT(sizeof(struct fs) == 1376);
 #define FS_FLAGS_UPDATED 0x0080	/* flags have been moved to new location */
 #define FS_NFS4ACLS	0x0100	/* file system has NFSv4 ACLs enabled */
 #define FS_INDEXDIRS	0x0200	/* kernel supports indexed directories */
+#define	FS_TRIM		0x0400	/* issue BIO_DELETE for deleted blocks */
 
 /*
  * Macros to access bits in the fs_active array.
diff --git a/sys/ufs/ufs/ufsmount.h b/sys/ufs/ufs/ufsmount.h
index 03edd73..b13db40 100644
--- a/sys/ufs/ufs/ufsmount.h
+++ b/sys/ufs/ufs/ufsmount.h
@@ -95,6 +95,7 @@ struct ufsmount {
 	time_t	um_itime[MAXQUOTAS];		/* inode quota time limit */
 	char	um_qflags[MAXQUOTAS];		/* quota specific flags */
 	int64_t	um_savedmaxfilesize;		/* XXX - limit maxfilesize */
+	int	um_candelete;			/* devvp supports TRIM */
 	int	(*um_balloc)(struct vnode *, off_t, int, struct ucred *, int, struct buf **);
 	int	(*um_blkatoff)(struct vnode *, off_t, char **, struct buf **);
 	int	(*um_truncate)(struct vnode *, off_t, int, struct ucred *, struct thread *);