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yaml
---
r: 273833
b: refs/heads/master
c: b3cb0d6
h: refs/heads/master
i:
  273831: 63b960b
v: v3
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Li Dongyang authored and Konrad Rzeszutek Wilk committed Oct 13, 2011
1 parent 5540074 commit 5a54e56
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Showing 4 changed files with 207 additions and 32 deletions.
2 changes: 1 addition & 1 deletion [refs]
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Original file line number Diff line number Diff line change
@@ -1,2 +1,2 @@
---
refs/heads/master: 32a8d26cc9b96629269e04ee6c583e14398f6f47
refs/heads/master: b3cb0d6adc4bbc70b5e37e49a6068e973545ead7
86 changes: 72 additions & 14 deletions trunk/drivers/block/xen-blkback/blkback.c
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Original file line number Diff line number Diff line change
Expand Up @@ -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>
Expand Down Expand Up @@ -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"
" | ds %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_ds_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_ds_req = 0;
}

int xen_blkif_schedule(void *arg)
Expand Down Expand Up @@ -410,6 +416,42 @@ static int xen_blkbk_map(struct blkif_request *req,
return ret;
}

static void xen_blk_discard(struct xen_blkif *blkif, struct blkif_request *req)
{
int err = 0;
int status = BLKIF_RSP_OKAY;
struct block_device *bdev = blkif->vbd.bdev;

if (blkif->blk_backend_type == BLKIF_BACKEND_PHY)
/* just forward the discard request */
err = blkdev_issue_discard(bdev,
req->u.discard.sector_number,
req->u.discard.nr_sectors,
GFP_KERNEL, 0);
else if (blkif->blk_backend_type == BLKIF_BACKEND_FILE) {
/* 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,
req->u.discard.sector_number << 9,
req->u.discard.nr_sectors << 9);
else
err = -EOPNOTSUPP;
} else
err = -EOPNOTSUPP;

if (err == -EOPNOTSUPP) {
pr_debug(DRV_PFX "discard op failed, not supported\n");
status = BLKIF_RSP_EOPNOTSUPP;
} else if (err)
status = BLKIF_RSP_ERROR;

make_response(blkif, req->id, req->operation, status);
}

/*
* Completion callback on the bio's. Called as bh->b_end_io()
*/
Expand Down Expand Up @@ -563,6 +605,10 @@ static int dispatch_rw_block_io(struct xen_blkif *blkif,
blkif->st_f_req++;
operation = WRITE_FLUSH;
break;
case BLKIF_OP_DISCARD:
blkif->st_ds_req++;
operation = REQ_DISCARD;
break;
case BLKIF_OP_WRITE_BARRIER:
default:
operation = 0; /* make gcc happy */
Expand All @@ -572,7 +618,8 @@ 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 &&
operation != REQ_DISCARD) ||
unlikely(nseg > BLKIF_MAX_SEGMENTS_PER_REQUEST)) {
pr_debug(DRV_PFX "Bad number of segments in request (%d)\n",
nseg);
Expand Down Expand Up @@ -627,10 +674,14 @@ 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_DISCARD &&
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 (in "!bio") if we are handling a BLKIF_OP_DISCARD.
*/
xen_blkif_get(blkif);

for (i = 0; i < nseg; i++) {
Expand All @@ -654,18 +705,25 @@ 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 discard. */
if (!bio) {
BUG_ON(operation != WRITE_FLUSH);
BUG_ON(operation != WRITE_FLUSH && operation != 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) {
xen_blk_discard(blkif, req);
xen_blkif_put(blkif);
free_req(pending_req);
return 0;
}
}

/*
Expand Down
93 changes: 76 additions & 17 deletions trunk/drivers/block/xen-blkback/common.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -63,13 +63,26 @@ struct blkif_common_response {

/* i386 protocol version */
#pragma pack(push, 4)

struct blkif_x86_32_request_rw {
blkif_sector_t sector_number;/* start sector idx on disk (r/w only) */
struct blkif_request_segment seg[BLKIF_MAX_SEGMENTS_PER_REQUEST];
};

struct blkif_x86_32_request_discard {
blkif_sector_t sector_number;/* start sector idx on disk (r/w only) */
uint64_t nr_sectors;
};

struct blkif_x86_32_request {
uint8_t operation; /* BLKIF_OP_??? */
uint8_t nr_segments; /* number of segments */
blkif_vdev_t handle; /* only for read/write requests */
uint64_t id; /* private guest value, echoed in resp */
blkif_sector_t sector_number;/* start sector idx on disk (r/w only) */
struct blkif_request_segment seg[BLKIF_MAX_SEGMENTS_PER_REQUEST];
union {
struct blkif_x86_32_request_rw rw;
struct blkif_x86_32_request_discard discard;
} u;
};
struct blkif_x86_32_response {
uint64_t id; /* copied from request */
Expand All @@ -79,13 +92,26 @@ struct blkif_x86_32_response {
#pragma pack(pop)

/* x86_64 protocol version */

struct blkif_x86_64_request_rw {
blkif_sector_t sector_number;/* start sector idx on disk (r/w only) */
struct blkif_request_segment seg[BLKIF_MAX_SEGMENTS_PER_REQUEST];
};

struct blkif_x86_64_request_discard {
blkif_sector_t sector_number;/* start sector idx on disk (r/w only) */
uint64_t nr_sectors;
};

struct blkif_x86_64_request {
uint8_t operation; /* BLKIF_OP_??? */
uint8_t nr_segments; /* number of segments */
blkif_vdev_t handle; /* only for read/write requests */
uint64_t __attribute__((__aligned__(8))) id;
blkif_sector_t sector_number;/* start sector idx on disk (r/w only) */
struct blkif_request_segment seg[BLKIF_MAX_SEGMENTS_PER_REQUEST];
union {
struct blkif_x86_64_request_rw rw;
struct blkif_x86_64_request_discard discard;
} u;
};
struct blkif_x86_64_response {
uint64_t __attribute__((__aligned__(8))) id;
Expand Down Expand Up @@ -113,6 +139,11 @@ enum blkif_protocol {
BLKIF_PROTOCOL_X86_64 = 3,
};

enum blkif_backend_type {
BLKIF_BACKEND_PHY = 1,
BLKIF_BACKEND_FILE = 2,
};

struct xen_vbd {
/* What the domain refers to this vbd as. */
blkif_vdev_t handle;
Expand All @@ -138,6 +169,7 @@ struct xen_blkif {
unsigned int irq;
/* Comms information. */
enum blkif_protocol blk_protocol;
enum blkif_backend_type blk_backend_type;
union blkif_back_rings blk_rings;
struct vm_struct *blk_ring_area;
/* The VBD attached to this interface. */
Expand All @@ -159,6 +191,7 @@ struct xen_blkif {
int st_wr_req;
int st_oo_req;
int st_f_req;
int st_ds_req;
int st_rd_sect;
int st_wr_sect;

Expand All @@ -182,7 +215,7 @@ 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;
};
Expand All @@ -206,12 +239,25 @@ static inline void blkif_get_x86_32_req(struct blkif_request *dst,
dst->nr_segments = src->nr_segments;
dst->handle = src->handle;
dst->id = src->id;
dst->u.rw.sector_number = src->sector_number;
barrier();
if (n > dst->nr_segments)
n = dst->nr_segments;
for (i = 0; i < n; i++)
dst->u.rw.seg[i] = src->seg[i];
switch (src->operation) {
case BLKIF_OP_READ:
case BLKIF_OP_WRITE:
case BLKIF_OP_WRITE_BARRIER:
case BLKIF_OP_FLUSH_DISKCACHE:
dst->u.rw.sector_number = src->u.rw.sector_number;
barrier();
if (n > dst->nr_segments)
n = dst->nr_segments;
for (i = 0; i < n; i++)
dst->u.rw.seg[i] = src->u.rw.seg[i];
break;
case BLKIF_OP_DISCARD:
dst->u.discard.sector_number = src->u.discard.sector_number;
dst->u.discard.nr_sectors = src->u.discard.nr_sectors;
break;
default:
break;
}
}

static inline void blkif_get_x86_64_req(struct blkif_request *dst,
Expand All @@ -222,12 +268,25 @@ static inline void blkif_get_x86_64_req(struct blkif_request *dst,
dst->nr_segments = src->nr_segments;
dst->handle = src->handle;
dst->id = src->id;
dst->u.rw.sector_number = src->sector_number;
barrier();
if (n > dst->nr_segments)
n = dst->nr_segments;
for (i = 0; i < n; i++)
dst->u.rw.seg[i] = src->seg[i];
switch (src->operation) {
case BLKIF_OP_READ:
case BLKIF_OP_WRITE:
case BLKIF_OP_WRITE_BARRIER:
case BLKIF_OP_FLUSH_DISKCACHE:
dst->u.rw.sector_number = src->u.rw.sector_number;
barrier();
if (n > dst->nr_segments)
n = dst->nr_segments;
for (i = 0; i < n; i++)
dst->u.rw.seg[i] = src->u.rw.seg[i];
break;
case BLKIF_OP_DISCARD:
dst->u.discard.sector_number = src->u.discard.sector_number;
dst->u.discard.nr_sectors = src->u.discard.nr_sectors;
break;
default:
break;
}
}

#endif /* __XEN_BLKIF__BACKEND__COMMON_H__ */
58 changes: 58 additions & 0 deletions trunk/drivers/block/xen-blkback/xenbus.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -272,6 +272,7 @@ 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(ds_req, "%d\n", be->blkif->st_ds_req);
VBD_SHOW(rd_sect, "%d\n", be->blkif->st_rd_sect);
VBD_SHOW(wr_sect, "%d\n", be->blkif->st_wr_sect);

Expand All @@ -280,6 +281,7 @@ static struct attribute *xen_vbdstat_attrs[] = {
&dev_attr_rd_req.attr,
&dev_attr_wr_req.attr,
&dev_attr_f_req.attr,
&dev_attr_ds_req.attr,
&dev_attr_rd_sect.attr,
&dev_attr_wr_sect.attr,
NULL
Expand Down Expand Up @@ -419,6 +421,60 @@ int xen_blkbk_flush_diskcache(struct xenbus_transaction xbt,
return err;
}

int xen_blkbk_discard(struct xenbus_transaction xbt, struct backend_info *be)
{
struct xenbus_device *dev = be->dev;
struct xen_blkif *blkif = be->blkif;
char *type;
int err;
int state = 0;

type = xenbus_read(XBT_NIL, dev->nodename, "type", NULL);
if (!IS_ERR(type)) {
if (strncmp(type, "file", 4) == 0) {
state = 1;
blkif->blk_backend_type = BLKIF_BACKEND_FILE;
}
if (strncmp(type, "phy", 3) == 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;
blkif->blk_backend_type = BLKIF_BACKEND_PHY;
}
}
} else {
err = PTR_ERR(type);
xenbus_dev_fatal(dev, err, "reading type");
goto out;
}

err = xenbus_printf(xbt, dev->nodename, "feature-discard",
"%d", state);
if (err)
xenbus_dev_fatal(dev, err, "writing feature-discard");
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
Expand Down Expand Up @@ -650,6 +706,8 @@ static void connect(struct backend_info *be)
if (err)
goto abort;

err = xen_blkbk_discard(xbt, be);

err = xenbus_printf(xbt, dev->nodename, "sectors", "%llu",
(unsigned long long)vbd_sz(&be->blkif->vbd));
if (err) {
Expand Down

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