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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH V2 3/3] xen-blkback: handle trim request in backend driver
Now blkback driver can handle the trim request from guest, we will
forward the request to phy device if it really has trim support, or we'll
punch a hole on the image file.
Signed-off-by: Li Dongyang <lidongyang@xxxxxxxxxx>
---
drivers/block/xen-blkback/blkback.c | 85 +++++++++++++++++++++++++++++------
drivers/block/xen-blkback/common.h | 4 +-
drivers/block/xen-blkback/xenbus.c | 61 +++++++++++++++++++++++++
3 files changed, 135 insertions(+), 15 deletions(-)
diff --git a/drivers/block/xen-blkback/blkback.c
b/drivers/block/xen-blkback/blkback.c
index 2330a9a..5acc37a 100644
--- a/drivers/block/xen-blkback/blkback.c
+++ b/drivers/block/xen-blkback/blkback.c
@@ -39,6 +39,9 @@
#include <linux/list.h>
#include <linux/delay.h>
#include <linux/freezer.h>
+#include <linux/loop.h>
+#include <linux/falloc.h>
+#include <linux/fs.h>
#include <xen/events.h>
#include <xen/page.h>
@@ -258,13 +261,16 @@ irqreturn_t xen_blkif_be_int(int irq, void *dev_id)
static void print_stats(struct xen_blkif *blkif)
{
- pr_info("xen-blkback (%s): oo %3d | rd %4d | wr %4d | f %4d\n",
+ pr_info("xen-blkback (%s): oo %3d | rd %4d | wr %4d | f %4d"
+ " | tr %4d\n",
current->comm, blkif->st_oo_req,
- blkif->st_rd_req, blkif->st_wr_req, blkif->st_f_req);
+ blkif->st_rd_req, blkif->st_wr_req,
+ blkif->st_f_req, blkif->st_tr_req);
blkif->st_print = jiffies + msecs_to_jiffies(10 * 1000);
blkif->st_rd_req = 0;
blkif->st_wr_req = 0;
blkif->st_oo_req = 0;
+ blkif->st_tr_req = 0;
}
int xen_blkif_schedule(void *arg)
@@ -563,6 +569,10 @@ static int dispatch_rw_block_io(struct xen_blkif *blkif,
blkif->st_f_req++;
operation = WRITE_FLUSH;
break;
+ case BLKIF_OP_TRIM:
+ blkif->st_tr_req++;
+ operation = REQ_DISCARD;
+ break;
case BLKIF_OP_WRITE_BARRIER:
default:
operation = 0; /* make gcc happy */
@@ -572,7 +582,7 @@ static int dispatch_rw_block_io(struct xen_blkif *blkif,
/* Check that the number of segments is sane. */
nseg = req->nr_segments;
- if (unlikely(nseg == 0 && operation != WRITE_FLUSH) ||
+ if (unlikely(nseg == 0 && operation != (WRITE_FLUSH | REQ_DISCARD)) ||
unlikely(nseg > BLKIF_MAX_SEGMENTS_PER_REQUEST)) {
pr_debug(DRV_PFX "Bad number of segments in request (%d)\n",
nseg);
@@ -627,10 +637,13 @@ static int dispatch_rw_block_io(struct xen_blkif *blkif,
* the hypercall to unmap the grants - that is all done in
* xen_blkbk_unmap.
*/
- if (xen_blkbk_map(req, pending_req, seg))
+ if (operation != BLKIF_OP_TRIM && xen_blkbk_map(req, pending_req, seg))
goto fail_flush;
- /* This corresponding xen_blkif_put is done in __end_block_io_op */
+ /*
+ * This corresponding xen_blkif_put is done in __end_block_io_op, or
+ * below if we are handling a BLKIF_OP_TRIM.
+ */
xen_blkif_get(blkif);
for (i = 0; i < nseg; i++) {
@@ -654,18 +667,62 @@ static int dispatch_rw_block_io(struct xen_blkif *blkif,
preq.sector_number += seg[i].nsec;
}
- /* This will be hit if the operation was a flush. */
+ /* This will be hit if the operation was a flush or trim. */
if (!bio) {
- BUG_ON(operation != WRITE_FLUSH);
+ BUG_ON(operation != (WRITE_FLUSH | REQ_DISCARD));
- bio = bio_alloc(GFP_KERNEL, 0);
- if (unlikely(bio == NULL))
- goto fail_put_bio;
+ if (operation == WRITE_FLUSH) {
+ bio = bio_alloc(GFP_KERNEL, 0);
+ if (unlikely(bio == NULL))
+ goto fail_put_bio;
- biolist[nbio++] = bio;
- bio->bi_bdev = preq.bdev;
- bio->bi_private = pending_req;
- bio->bi_end_io = end_block_io_op;
+ biolist[nbio++] = bio;
+ bio->bi_bdev = preq.bdev;
+ bio->bi_private = pending_req;
+ bio->bi_end_io = end_block_io_op;
+ } else if (operation == REQ_DISCARD) {
+ int err = 0;
+ int status = BLKIF_RSP_OKAY;
+ struct block_device *bdev = blkif->vbd.bdev;
+
+ preq.nr_sects = req->u.trim.nr_sectors;
+ if (blkif->vbd.type & VDISK_PHY_BACKEND)
+ /* just forward the trim request */
+ err = blkdev_issue_discard(bdev,
+ preq.sector_number,
+ preq.nr_sects,
+ GFP_KERNEL, 0);
+ else if (blkif->vbd.type & VDISK_FILE_BACKEND) {
+ /* punch a hole in the backing file */
+ struct loop_device *lo =
+ bdev->bd_disk->private_data;
+ struct file *file = lo->lo_backing_file;
+
+ if (file->f_op->fallocate)
+ err = file->f_op->fallocate(file,
+ FALLOC_FL_KEEP_SIZE |
+ FALLOC_FL_PUNCH_HOLE,
+ preq.sector_number << 9,
+ preq.nr_sects << 9);
+ else
+ err = -EOPNOTSUPP;
+ } else
+ status = BLKIF_RSP_EOPNOTSUPP;
+
+ if (err == -EOPNOTSUPP) {
+ DPRINTK("blkback: discard op failed, "
+ "not supported\n");
+ status = BLKIF_RSP_EOPNOTSUPP;
+ } else if (err)
+ status = BLKIF_RSP_ERROR;
+
+ if (status == BLKIF_RSP_OKAY)
+ blkif->st_tr_sect += preq.nr_sects;
+ make_response(blkif, req->id, req->operation, status);
+ xen_blkif_put(blkif);
+ free_req(pending_req);
+ return 0;
+ }
}
/*
diff --git a/drivers/block/xen-blkback/common.h
b/drivers/block/xen-blkback/common.h
index 9e40b28..1fef727 100644
--- a/drivers/block/xen-blkback/common.h
+++ b/drivers/block/xen-blkback/common.h
@@ -159,8 +159,10 @@ struct xen_blkif {
int st_wr_req;
int st_oo_req;
int st_f_req;
+ int st_tr_req;
int st_rd_sect;
int st_wr_sect;
+ int st_tr_sect;
wait_queue_head_t waiting_to_free;
@@ -182,7 +184,7 @@ struct xen_blkif {
struct phys_req {
unsigned short dev;
- unsigned short nr_sects;
+ blkif_sector_t nr_sects;
struct block_device *bdev;
blkif_sector_t sector_number;
};
diff --git a/drivers/block/xen-blkback/xenbus.c
b/drivers/block/xen-blkback/xenbus.c
index 3f129b4..05ea8e0 100644
--- a/drivers/block/xen-blkback/xenbus.c
+++ b/drivers/block/xen-blkback/xenbus.c
@@ -272,16 +272,20 @@ VBD_SHOW(oo_req, "%d\n", be->blkif->st_oo_req);
VBD_SHOW(rd_req, "%d\n", be->blkif->st_rd_req);
VBD_SHOW(wr_req, "%d\n", be->blkif->st_wr_req);
VBD_SHOW(f_req, "%d\n", be->blkif->st_f_req);
+VBD_SHOW(tr_req, "%d\n", be->blkif->st_tr_req);
VBD_SHOW(rd_sect, "%d\n", be->blkif->st_rd_sect);
VBD_SHOW(wr_sect, "%d\n", be->blkif->st_wr_sect);
+VBD_SHOW(tr_sect, "%d\n", be->blkif->st_tr_sect);
static struct attribute *xen_vbdstat_attrs[] = {
&dev_attr_oo_req.attr,
&dev_attr_rd_req.attr,
&dev_attr_wr_req.attr,
&dev_attr_f_req.attr,
+ &dev_attr_tr_req.attr,
&dev_attr_rd_sect.attr,
&dev_attr_wr_sect.attr,
+ &dev_attr_tr_sect.attr,
NULL
};
@@ -419,6 +423,59 @@ int xen_blkbk_flush_diskcache(struct xenbus_transaction
xbt,
return err;
}
+int xen_blkbk_trim(struct xenbus_transaction xbt, struct backend_info *be)
+{
+ struct xenbus_device *dev = be->dev;
+ struct xen_vbd *vbd = &be->blkif->vbd;
+ char *type;
+ int err;
+ int state = 0;
+
+ type = xenbus_read(XBT_NIL, dev->nodename, "type", NULL);
+ if (!IS_ERR(type)) {
+ if (strcmp(type, "file") == 0)
+ state = 1;
+ vbd->type |= VDISK_FILE_BACKEND;
+ if (strcmp(type, "phy") == 0) {
+ struct block_device *bdev = be->blkif->vbd.bdev;
+ struct request_queue *q = bdev_get_queue(bdev);
+ if (blk_queue_discard(q)) {
+ err = xenbus_printf(xbt, dev->nodename,
+ "discard_granularity", "%u",
+ q->limits.discard_granularity);
+ if (err) {
+ xenbus_dev_fatal(dev, err,
+ "writing discard_granularity");
+ goto kfree;
+ }
+ err = xenbus_printf(xbt, dev->nodename,
+ "discard_alignment", "%u",
+ q->limits.discard_alignment);
+ if (err) {
+ xenbus_dev_fatal(dev, err,
+ "writing discard_alignment");
+ goto kfree;
+ }
+ state = 1;
+ vbd->type |= VDISK_PHY_BACKEND;
+ }
+ }
+ } else {
+ err = PTR_ERR(type);
+ xenbus_dev_fatal(dev, err, "reading type");
+ goto out;
+ }
+
+ err = xenbus_printf(xbt, dev->nodename, "feature-trim",
+ "%d", state);
+ if (err)
+ xenbus_dev_fatal(dev, err, "writing feature-trim");
+kfree:
+ kfree(type);
+out:
+ return err;
+}
+
/*
* Entry point to this code when a new device is created. Allocate the basic
* structures, and watch the store waiting for the hotplug scripts to tell us
@@ -650,6 +707,10 @@ again:
if (err)
goto abort;
+ err = xen_blkbk_trim(xbt, be);
+ if (err)
+ goto abort;
+
err = xenbus_printf(xbt, dev->nodename, "sectors", "%llu",
(unsigned long long)vbd_sz(&be->blkif->vbd));
if (err) {
--
1.7.6
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