zio: rename ZIO_TYPE_IOCTL to ZIO_TYPE_FLUSH

The only possible ioctl is a flush, and any other kind of meta-operation
introduced in the future is likely to have different semantics (much
like trim did). So, lets just call it what it is.

Sponsored-by: Klara, Inc.
Sponsored-by: Wasabi Technology, Inc.
Signed-off-by: Rob Norris <robn@despairlabs.com>

include/sys/fs/zfs.h

@@ -1094,11 +1094,17 @@ typedef enum zio_type {
 	ZIO_TYPE_WRITE,
 	ZIO_TYPE_FREE,
 	ZIO_TYPE_CLAIM,
-	ZIO_TYPE_IOCTL,
+	ZIO_TYPE_FLUSH,
 	ZIO_TYPE_TRIM,
 	ZIO_TYPES
 } zio_type_t;
 
+/*
+ * Compatbility: _IOCTL was renamed to _FLUSH; keep the old name available to
+ * user programs.
+ */
+#define	ZIO_TYPE_IOCTL	ZIO_TYPE_FLUSH
+
 /*
  * Pool statistics.  Note: all fields should be 64-bit because this
  * is passed between kernel and userland as an nvlist uint64 array.

include/sys/zio_impl.h

@@ -40,15 +40,15 @@ extern "C" {
  *
  * The ZFS I/O pipeline is comprised of various stages which are defined
  * in the zio_stage enum below. The individual stages are used to construct
- * these basic I/O operations: Read, Write, Free, Claim, Ioctl and Trim.
+ * these basic I/O operations: Read, Write, Free, Claim, Flush and Trim.
  *
  * I/O operations: (XXX - provide detail for each of the operations)
  *
  * Read:
  * Write:
  * Free:
  * Claim:
- * Ioctl:
+ * Flush:
  * Trim:
  *
  * Although the most common pipeline are used by the basic I/O operations
@@ -122,7 +122,7 @@ extern "C" {
  * zio pipeline stage definitions
  */
 enum zio_stage {
-	ZIO_STAGE_OPEN			= 1 << 0,	/* RWFCIT */
+	ZIO_STAGE_OPEN			= 1 << 0,	/* RWFCXT */
 
 	ZIO_STAGE_READ_BP_INIT		= 1 << 1,	/* R----- */
 	ZIO_STAGE_WRITE_BP_INIT		= 1 << 2,	/* -W---- */
@@ -150,15 +150,15 @@ enum zio_stage {
 	ZIO_STAGE_DVA_FREE		= 1 << 18,	/* --F--- */
 	ZIO_STAGE_DVA_CLAIM		= 1 << 19,	/* ---C-- */
 
-	ZIO_STAGE_READY			= 1 << 20,	/* RWFCIT */
+	ZIO_STAGE_READY			= 1 << 20,	/* RWFCXT */
 
-	ZIO_STAGE_VDEV_IO_START		= 1 << 21,	/* RW--IT */
+	ZIO_STAGE_VDEV_IO_START		= 1 << 21,	/* RW--XT */
 	ZIO_STAGE_VDEV_IO_DONE		= 1 << 22,	/* RW---T */
-	ZIO_STAGE_VDEV_IO_ASSESS	= 1 << 23,	/* RW--IT */
+	ZIO_STAGE_VDEV_IO_ASSESS	= 1 << 23,	/* RW--XT */
 
 	ZIO_STAGE_CHECKSUM_VERIFY	= 1 << 24,	/* R----- */
 
-	ZIO_STAGE_DONE			= 1 << 25	/* RWFCIT */
+	ZIO_STAGE_DONE			= 1 << 25	/* RWFCXT */
 };
 
 #define	ZIO_ROOT_PIPELINE			\
@@ -259,7 +259,7 @@ enum zio_stage {
 	(ZIO_INTERLOCK_STAGES |			\
 	ZIO_STAGE_DVA_CLAIM)
 
-#define	ZIO_IOCTL_PIPELINE			\
+#define	ZIO_FLUSH_PIPELINE			\
 	(ZIO_INTERLOCK_STAGES |			\
 	ZIO_STAGE_VDEV_IO_START |		\
 	ZIO_STAGE_VDEV_IO_ASSESS)

man/man8/zpool-events.8

@@ -364,7 +364,7 @@ that is, the bits set in the good data which are cleared in the bad data.
 .Sh I/O STAGES
 The ZFS I/O pipeline is comprised of various stages which are defined below.
 The individual stages are used to construct these basic I/O
-operations: Read, Write, Free, Claim, Ioctl and Trim.
+operations: Read, Write, Free, Claim, Flush and Trim.
 These stages may be
 set on an event to describe the life cycle of a given I/O request.
 .Pp
@@ -373,7 +373,7 @@ tab(:);
 l l l .
 Stage:Bit Mask:Operations
 _:_:_
-ZIO_STAGE_OPEN:0x00000001:RWFCIT
+ZIO_STAGE_OPEN:0x00000001:RWFCXT
 
 ZIO_STAGE_READ_BP_INIT:0x00000002:R-----
 ZIO_STAGE_WRITE_BP_INIT:0x00000004:-W----
@@ -403,13 +403,13 @@ ZIO_STAGE_DVA_CLAIM:0x00080000:---C--
 
 ZIO_STAGE_READY:0x00100000:RWFCIT
 
-ZIO_STAGE_VDEV_IO_START:0x00200000:RW--IT
+ZIO_STAGE_VDEV_IO_START:0x00200000:RW--XT
 ZIO_STAGE_VDEV_IO_DONE:0x00400000:RW---T
-ZIO_STAGE_VDEV_IO_ASSESS:0x00800000:RW--IT
+ZIO_STAGE_VDEV_IO_ASSESS:0x00800000:RW--XT
 
 ZIO_STAGE_CHECKSUM_VERIFY:0x01000000:R-----
 
-ZIO_STAGE_DONE:0x02000000:RWFCIT
+ZIO_STAGE_DONE:0x02000000:RWFCXT
 .TE
 .
 .Sh I/O FLAGS

module/os/freebsd/zfs/vdev_file.c

@@ -247,7 +247,7 @@ vdev_file_io_start(zio_t *zio)
 	vdev_t *vd = zio->io_vd;
 	vdev_file_t *vf = vd->vdev_tsd;
 
-	if (zio->io_type == ZIO_TYPE_IOCTL) {
+	if (zio->io_type == ZIO_TYPE_FLUSH) {
 		/* XXPOLICY */
 		if (!vdev_readable(vd)) {
 			zio->io_error = SET_ERROR(ENXIO);

module/os/freebsd/zfs/vdev_geom.c

@@ -1053,7 +1053,7 @@ vdev_geom_io_intr(struct bio *bp)
 	/*
 	 * We have to split bio freeing into two parts, because the ABD code
 	 * cannot be called in this context and vdev_op_io_done is not called
-	 * for ZIO_TYPE_IOCTL zio-s.
+	 * for ZIO_TYPE_FLUSH zio-s.
 	 */
 	if (zio->io_type != ZIO_TYPE_READ && zio->io_type != ZIO_TYPE_WRITE) {
 		g_destroy_bio(bp);
@@ -1153,7 +1153,7 @@ vdev_geom_io_start(zio_t *zio)
 
 	vd = zio->io_vd;
 
-	if (zio->io_type == ZIO_TYPE_IOCTL) {
+	if (zio->io_type == ZIO_TYPE_FLUSH) {
 		/* XXPOLICY */
 		if (!vdev_readable(vd)) {
 			zio->io_error = SET_ERROR(ENXIO);
@@ -1181,7 +1181,7 @@ vdev_geom_io_start(zio_t *zio)
 	ASSERT(zio->io_type == ZIO_TYPE_READ ||
 	    zio->io_type == ZIO_TYPE_WRITE ||
 	    zio->io_type == ZIO_TYPE_TRIM ||
-	    zio->io_type == ZIO_TYPE_IOCTL);
+	    zio->io_type == ZIO_TYPE_FLUSH);
 
 	cp = vd->vdev_tsd;
 	if (cp == NULL) {
@@ -1233,7 +1233,7 @@ vdev_geom_io_start(zio_t *zio)
 		bp->bio_offset = zio->io_offset;
 		bp->bio_length = zio->io_size;
 		break;
-	case ZIO_TYPE_IOCTL:
+	case ZIO_TYPE_FLUSH:
 		bp->bio_cmd = BIO_FLUSH;
 		bp->bio_data = NULL;
 		bp->bio_offset = cp->provider->mediasize;

module/os/linux/zfs/vdev_disk.c

@@ -1351,7 +1351,7 @@ vdev_disk_io_start(zio_t *zio)
 	}
 
 	switch (zio->io_type) {
-	case ZIO_TYPE_IOCTL:
+	case ZIO_TYPE_FLUSH:
 
 		if (!vdev_readable(v)) {
 			rw_exit(&vd->vd_lock);

module/os/linux/zfs/vdev_file.c

@@ -242,7 +242,7 @@ vdev_file_io_start(zio_t *zio)
 	vdev_t *vd = zio->io_vd;
 	vdev_file_t *vf = vd->vdev_tsd;
 
-	if (zio->io_type == ZIO_TYPE_IOCTL) {
+	if (zio->io_type == ZIO_TYPE_FLUSH) {
 		/* XXPOLICY */
 		if (!vdev_readable(vd)) {
 			zio->io_error = SET_ERROR(ENXIO);

module/zfs/spa.c

@@ -180,7 +180,7 @@ static zio_taskq_info_t zio_taskqs[ZIO_TYPES][ZIO_TASKQ_TYPES] = {
 	{ ZTI_SYNC,	ZTI_N(5),	ZTI_SCALE,	ZTI_N(5) }, /* WRITE */
 	{ ZTI_SCALE,	ZTI_NULL,	ZTI_ONE,	ZTI_NULL }, /* FREE */
 	{ ZTI_ONE,	ZTI_NULL,	ZTI_ONE,	ZTI_NULL }, /* CLAIM */
-	{ ZTI_ONE,	ZTI_NULL,	ZTI_ONE,	ZTI_NULL }, /* IOCTL */
+	{ ZTI_ONE,	ZTI_NULL,	ZTI_ONE,	ZTI_NULL }, /* FLUSH */
 	{ ZTI_N(4),	ZTI_NULL,	ZTI_ONE,	ZTI_NULL }, /* TRIM */
 };
 

module/zfs/vdev.c

@@ -4924,11 +4924,11 @@ vdev_stat_update(zio_t *zio, uint64_t psize)
 
 			/*
 			 * TRIM ops and bytes are reported to user space as
-			 * ZIO_TYPE_IOCTL.  This is done to preserve the
+			 * ZIO_TYPE_FLUSH.  This is done to preserve the
 			 * vdev_stat_t structure layout for user space.
 			 */
 			if (type == ZIO_TYPE_TRIM)
-				vs_type = ZIO_TYPE_IOCTL;
+				vs_type = ZIO_TYPE_FLUSH;
 
 			/*
 			 * Solely for the purposes of 'zpool iostat -lqrw'
@@ -6239,12 +6239,12 @@ vdev_prop_get(vdev_t *vd, nvlist_t *innvl, nvlist_t *outnvl)
 			case VDEV_PROP_OPS_TRIM:
 				/*
 				 * TRIM ops and bytes are reported to user
-				 * space as ZIO_TYPE_IOCTL.  This is done to
+				 * space as ZIO_TYPE_FLUSH.  This is done to
 				 * preserve the vdev_stat_t structure layout
 				 * for user space.
 				 */
 				vdev_prop_add_list(outnvl, propname, NULL,
-				    vd->vdev_stat.vs_ops[ZIO_TYPE_IOCTL],
+				    vd->vdev_stat.vs_ops[ZIO_TYPE_FLUSH],
 				    ZPROP_SRC_NONE);
 				continue;
 			case VDEV_PROP_BYTES_NULL:
@@ -6275,12 +6275,12 @@ vdev_prop_get(vdev_t *vd, nvlist_t *innvl, nvlist_t *outnvl)
 			case VDEV_PROP_BYTES_TRIM:
 				/*
 				 * TRIM ops and bytes are reported to user
-				 * space as ZIO_TYPE_IOCTL.  This is done to
+				 * space as ZIO_TYPE_FLUSH.  This is done to
 				 * preserve the vdev_stat_t structure layout
 				 * for user space.
 				 */
 				vdev_prop_add_list(outnvl, propname, NULL,
-				    vd->vdev_stat.vs_bytes[ZIO_TYPE_IOCTL],
+				    vd->vdev_stat.vs_bytes[ZIO_TYPE_FLUSH],
 				    ZPROP_SRC_NONE);
 				continue;
 			case VDEV_PROP_REMOVING:

module/zfs/vdev_draid.c

@@ -2548,11 +2548,11 @@ vdev_draid_read_config_spare(vdev_t *vd)
 }
 
 /*
- * Handle any ioctl requested of the distributed spare.  Only flushes
- * are supported in which case all children must be flushed.
+ * Handle any flush requested of the distributed spare. All children must be
+ * flushed.
  */
 static int
-vdev_draid_spare_ioctl(zio_t *zio)
+vdev_draid_spare_flush(zio_t *zio)
 {
 	vdev_t *vd = zio->io_vd;
 	int error = 0;
@@ -2592,8 +2592,8 @@ vdev_draid_spare_io_start(zio_t *zio)
 	}
 
 	switch (zio->io_type) {
-	case ZIO_TYPE_IOCTL:
-		zio->io_error = vdev_draid_spare_ioctl(zio);
+	case ZIO_TYPE_FLUSH:
+		zio->io_error = vdev_draid_spare_flush(zio);
 		break;
 
 	case ZIO_TYPE_WRITE:

module/zfs/zio.c

@@ -63,7 +63,7 @@ const char *const zio_type_name[ZIO_TYPES] = {
 	 * Note: Linux kernel thread name length is limited
 	 * so these names will differ from upstream open zfs.
 	 */
-	"z_null", "z_rd", "z_wr", "z_fr", "z_cl", "z_ioctl", "z_trim"
+	"z_null", "z_rd", "z_wr", "z_fr", "z_cl", "z_flush", "z_trim"
 };
 
 int zio_dva_throttle_enabled = B_TRUE;
@@ -1632,8 +1632,8 @@ zio_flush(zio_t *pio, vdev_t *vd)
 
 	if (vd->vdev_children == 0) {
 		zio_nowait(zio_create(pio, pio->io_spa, 0, NULL, NULL, 0, 0,
-		    NULL, NULL, ZIO_TYPE_IOCTL, ZIO_PRIORITY_NOW, flags, vd, 0,
-		    NULL, ZIO_STAGE_OPEN, ZIO_IOCTL_PIPELINE));
+		    NULL, NULL, ZIO_TYPE_FLUSH, ZIO_PRIORITY_NOW, flags, vd, 0,
+		    NULL, ZIO_STAGE_OPEN, ZIO_FLUSH_PIPELINE));
 	} else {
 		for (uint64_t c = 0; c < vd->vdev_children; c++)
 			zio_flush(pio, vd->vdev_child[c]);
@@ -4236,7 +4236,7 @@ zio_vdev_io_assess(zio_t *zio)
 	 * boolean flag so that we don't bother with it in the future.
 	 */
 	if ((zio->io_error == ENOTSUP || zio->io_error == ENOTTY) &&
-	    zio->io_type == ZIO_TYPE_IOCTL && vd != NULL)
+	    zio->io_type == ZIO_TYPE_FLUSH && vd != NULL)
 		vd->vdev_nowritecache = B_TRUE;
 
 	if (zio->io_error)