Merge branch 'stable/for-jens-3.2' of git://oss.oracle.com/git/kwilk/xen into for-3.2/drivers
diff --git a/drivers/block/xen-blkback/blkback.c b/drivers/block/xen-blkback/blkback.c
index 2330a9a..79efec2 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 @@
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)
@@ -410,6 +416,59 @@
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);
+}
+
+static void xen_blk_drain_io(struct xen_blkif *blkif)
+{
+ atomic_set(&blkif->drain, 1);
+ do {
+ /* The initial value is one, and one refcnt taken at the
+ * start of the xen_blkif_schedule thread. */
+ if (atomic_read(&blkif->refcnt) <= 2)
+ break;
+ wait_for_completion_interruptible_timeout(
+ &blkif->drain_complete, HZ);
+
+ if (!atomic_read(&blkif->drain))
+ break;
+ } while (!kthread_should_stop());
+ atomic_set(&blkif->drain, 0);
+}
+
/*
* Completion callback on the bio's. Called as bh->b_end_io()
*/
@@ -422,6 +481,11 @@
pr_debug(DRV_PFX "flush diskcache op failed, not supported\n");
xen_blkbk_flush_diskcache(XBT_NIL, pending_req->blkif->be, 0);
pending_req->status = BLKIF_RSP_EOPNOTSUPP;
+ } else if ((pending_req->operation == BLKIF_OP_WRITE_BARRIER) &&
+ (error == -EOPNOTSUPP)) {
+ pr_debug(DRV_PFX "write barrier op failed, not supported\n");
+ xen_blkbk_barrier(XBT_NIL, pending_req->blkif->be, 0);
+ pending_req->status = BLKIF_RSP_EOPNOTSUPP;
} else if (error) {
pr_debug(DRV_PFX "Buffer not up-to-date at end of operation,"
" error=%d\n", error);
@@ -438,6 +502,10 @@
make_response(pending_req->blkif, pending_req->id,
pending_req->operation, pending_req->status);
xen_blkif_put(pending_req->blkif);
+ if (atomic_read(&pending_req->blkif->refcnt) <= 2) {
+ if (atomic_read(&pending_req->blkif->drain))
+ complete(&pending_req->blkif->drain_complete);
+ }
free_req(pending_req);
}
}
@@ -532,7 +600,6 @@
return more_to_do;
}
-
/*
* Transmutation of the 'struct blkif_request' to a proper 'struct bio'
* and call the 'submit_bio' to pass it to the underlying storage.
@@ -549,6 +616,7 @@
int i, nbio = 0;
int operation;
struct blk_plug plug;
+ bool drain = false;
switch (req->operation) {
case BLKIF_OP_READ:
@@ -559,11 +627,16 @@
blkif->st_wr_req++;
operation = WRITE_ODIRECT;
break;
+ case BLKIF_OP_WRITE_BARRIER:
+ drain = true;
case BLKIF_OP_FLUSH_DISKCACHE:
blkif->st_f_req++;
operation = WRITE_FLUSH;
break;
- case BLKIF_OP_WRITE_BARRIER:
+ case BLKIF_OP_DISCARD:
+ blkif->st_ds_req++;
+ operation = REQ_DISCARD;
+ break;
default:
operation = 0; /* make gcc happy */
goto fail_response;
@@ -572,7 +645,8 @@
/* 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);
@@ -621,16 +695,25 @@
}
}
+ /* Wait on all outstanding I/O's and once that has been completed
+ * issue the WRITE_FLUSH.
+ */
+ if (drain)
+ xen_blk_drain_io(pending_req->blkif);
+
/*
* If we have failed at this point, we need to undo the M2P override,
* set gnttab_set_unmap_op on all of the grant references and perform
* the hypercall to unmap the grants - that is all done in
* xen_blkbk_unmap.
*/
- if (xen_blkbk_map(req, pending_req, seg))
+ if (operation != REQ_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++) {
@@ -654,18 +737,25 @@
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;
+ }
}
/*
@@ -685,7 +775,7 @@
if (operation == READ)
blkif->st_rd_sect += preq.nr_sects;
- else if (operation == WRITE || operation == WRITE_FLUSH)
+ else if (operation & WRITE)
blkif->st_wr_sect += preq.nr_sects;
return 0;
@@ -765,9 +855,9 @@
mmap_pages = xen_blkif_reqs * BLKIF_MAX_SEGMENTS_PER_REQUEST;
- blkbk->pending_reqs = kmalloc(sizeof(blkbk->pending_reqs[0]) *
+ blkbk->pending_reqs = kzalloc(sizeof(blkbk->pending_reqs[0]) *
xen_blkif_reqs, GFP_KERNEL);
- blkbk->pending_grant_handles = kzalloc(sizeof(blkbk->pending_grant_handles[0]) *
+ blkbk->pending_grant_handles = kmalloc(sizeof(blkbk->pending_grant_handles[0]) *
mmap_pages, GFP_KERNEL);
blkbk->pending_pages = kzalloc(sizeof(blkbk->pending_pages[0]) *
mmap_pages, GFP_KERNEL);
@@ -790,8 +880,6 @@
if (rc)
goto failed_init;
- memset(blkbk->pending_reqs, 0, sizeof(blkbk->pending_reqs));
-
INIT_LIST_HEAD(&blkbk->pending_free);
spin_lock_init(&blkbk->pending_free_lock);
init_waitqueue_head(&blkbk->pending_free_wq);
diff --git a/drivers/block/xen-blkback/common.h b/drivers/block/xen-blkback/common.h
index 9e40b28..e638457 100644
--- a/drivers/block/xen-blkback/common.h
+++ b/drivers/block/xen-blkback/common.h
@@ -46,7 +46,7 @@
#define DRV_PFX "xen-blkback:"
#define DPRINTK(fmt, args...) \
- pr_debug(DRV_PFX "(%s:%d) " fmt ".\n", \
+ pr_debug(DRV_PFX "(%s:%d) " fmt ".\n", \
__func__, __LINE__, ##args)
@@ -63,13 +63,26 @@
/* 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 */
@@ -79,13 +92,26 @@
#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;
@@ -113,6 +139,11 @@
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;
@@ -138,6 +169,7 @@
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. */
@@ -149,6 +181,9 @@
atomic_t refcnt;
wait_queue_head_t wq;
+ /* for barrier (drain) requests */
+ struct completion drain_complete;
+ atomic_t drain;
/* One thread per one blkif. */
struct task_struct *xenblkd;
unsigned int waiting_reqs;
@@ -159,6 +194,7 @@
int st_wr_req;
int st_oo_req;
int st_f_req;
+ int st_ds_req;
int st_rd_sect;
int st_wr_sect;
@@ -182,7 +218,7 @@
struct phys_req {
unsigned short dev;
- unsigned short nr_sects;
+ blkif_sector_t nr_sects;
struct block_device *bdev;
blkif_sector_t sector_number;
};
@@ -196,6 +232,8 @@
int xen_blkbk_flush_diskcache(struct xenbus_transaction xbt,
struct backend_info *be, int state);
+int xen_blkbk_barrier(struct xenbus_transaction xbt,
+ struct backend_info *be, int state);
struct xenbus_device *xen_blkbk_xenbus(struct backend_info *be);
static inline void blkif_get_x86_32_req(struct blkif_request *dst,
@@ -206,12 +244,25 @@
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,
@@ -222,12 +273,25 @@
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__ */
diff --git a/drivers/block/xen-blkback/xenbus.c b/drivers/block/xen-blkback/xenbus.c
index 3f129b4..a6d4303 100644
--- a/drivers/block/xen-blkback/xenbus.c
+++ b/drivers/block/xen-blkback/xenbus.c
@@ -114,6 +114,8 @@
spin_lock_init(&blkif->blk_ring_lock);
atomic_set(&blkif->refcnt, 1);
init_waitqueue_head(&blkif->wq);
+ init_completion(&blkif->drain_complete);
+ atomic_set(&blkif->drain, 0);
blkif->st_print = jiffies;
init_waitqueue_head(&blkif->waiting_to_free);
@@ -272,6 +274,7 @@
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);
@@ -280,6 +283,7 @@
&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
@@ -419,6 +423,73 @@
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;
+}
+int xen_blkbk_barrier(struct xenbus_transaction xbt,
+ struct backend_info *be, int state)
+{
+ struct xenbus_device *dev = be->dev;
+ int err;
+
+ err = xenbus_printf(xbt, dev->nodename, "feature-barrier",
+ "%d", state);
+ if (err)
+ xenbus_dev_fatal(dev, err, "writing feature-barrier");
+
+ 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
@@ -590,7 +661,7 @@
/*
* Enforce precondition before potential leak point.
- * blkif_disconnect() is idempotent.
+ * xen_blkif_disconnect() is idempotent.
*/
xen_blkif_disconnect(be->blkif);
@@ -611,7 +682,7 @@
break;
/* fall through if not online */
case XenbusStateUnknown:
- /* implies blkif_disconnect() via blkback_remove() */
+ /* implies xen_blkif_disconnect() via xen_blkbk_remove() */
device_unregister(&dev->dev);
break;
@@ -650,6 +721,11 @@
if (err)
goto abort;
+ err = xen_blkbk_discard(xbt, be);
+
+ /* If we can't advertise it is OK. */
+ err = xen_blkbk_barrier(xbt, be, be->blkif->vbd.flush_support);
+
err = xenbus_printf(xbt, dev->nodename, "sectors", "%llu",
(unsigned long long)vbd_sz(&be->blkif->vbd));
if (err) {
diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c
index b536a9c..773da7d 100644
--- a/drivers/block/xen-blkfront.c
+++ b/drivers/block/xen-blkfront.c
@@ -98,6 +98,9 @@
unsigned long shadow_free;
unsigned int feature_flush;
unsigned int flush_op;
+ unsigned int feature_discard;
+ unsigned int discard_granularity;
+ unsigned int discard_alignment;
int is_ready;
};
@@ -302,29 +305,36 @@
ring_req->operation = info->flush_op;
}
- ring_req->nr_segments = blk_rq_map_sg(req->q, req, info->sg);
- BUG_ON(ring_req->nr_segments > BLKIF_MAX_SEGMENTS_PER_REQUEST);
+ if (unlikely(req->cmd_flags & REQ_DISCARD)) {
+ /* id, sector_number and handle are set above. */
+ ring_req->operation = BLKIF_OP_DISCARD;
+ ring_req->nr_segments = 0;
+ ring_req->u.discard.nr_sectors = blk_rq_sectors(req);
+ } else {
+ ring_req->nr_segments = blk_rq_map_sg(req->q, req, info->sg);
+ BUG_ON(ring_req->nr_segments > BLKIF_MAX_SEGMENTS_PER_REQUEST);
- for_each_sg(info->sg, sg, ring_req->nr_segments, i) {
- buffer_mfn = pfn_to_mfn(page_to_pfn(sg_page(sg)));
- fsect = sg->offset >> 9;
- lsect = fsect + (sg->length >> 9) - 1;
- /* install a grant reference. */
- ref = gnttab_claim_grant_reference(&gref_head);
- BUG_ON(ref == -ENOSPC);
+ for_each_sg(info->sg, sg, ring_req->nr_segments, i) {
+ buffer_mfn = pfn_to_mfn(page_to_pfn(sg_page(sg)));
+ fsect = sg->offset >> 9;
+ lsect = fsect + (sg->length >> 9) - 1;
+ /* install a grant reference. */
+ ref = gnttab_claim_grant_reference(&gref_head);
+ BUG_ON(ref == -ENOSPC);
- gnttab_grant_foreign_access_ref(
- ref,
- info->xbdev->otherend_id,
- buffer_mfn,
- rq_data_dir(req) );
+ gnttab_grant_foreign_access_ref(
+ ref,
+ info->xbdev->otherend_id,
+ buffer_mfn,
+ rq_data_dir(req));
- info->shadow[id].frame[i] = mfn_to_pfn(buffer_mfn);
- ring_req->u.rw.seg[i] =
- (struct blkif_request_segment) {
- .gref = ref,
- .first_sect = fsect,
- .last_sect = lsect };
+ info->shadow[id].frame[i] = mfn_to_pfn(buffer_mfn);
+ ring_req->u.rw.seg[i] =
+ (struct blkif_request_segment) {
+ .gref = ref,
+ .first_sect = fsect,
+ .last_sect = lsect };
+ }
}
info->ring.req_prod_pvt++;
@@ -370,7 +380,9 @@
blk_start_request(req);
- if (req->cmd_type != REQ_TYPE_FS) {
+ if ((req->cmd_type != REQ_TYPE_FS) ||
+ ((req->cmd_flags & (REQ_FLUSH | REQ_FUA)) &&
+ !info->flush_op)) {
__blk_end_request_all(req, -EIO);
continue;
}
@@ -399,6 +411,7 @@
static int xlvbd_init_blk_queue(struct gendisk *gd, u16 sector_size)
{
struct request_queue *rq;
+ struct blkfront_info *info = gd->private_data;
rq = blk_init_queue(do_blkif_request, &blkif_io_lock);
if (rq == NULL)
@@ -406,6 +419,13 @@
queue_flag_set_unlocked(QUEUE_FLAG_VIRT, rq);
+ if (info->feature_discard) {
+ queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, rq);
+ blk_queue_max_discard_sectors(rq, get_capacity(gd));
+ rq->limits.discard_granularity = info->discard_granularity;
+ rq->limits.discard_alignment = info->discard_alignment;
+ }
+
/* Hard sector size and max sectors impersonate the equiv. hardware. */
blk_queue_logical_block_size(rq, sector_size);
blk_queue_max_hw_sectors(rq, 512);
@@ -722,6 +742,17 @@
error = (bret->status == BLKIF_RSP_OKAY) ? 0 : -EIO;
switch (bret->operation) {
+ case BLKIF_OP_DISCARD:
+ if (unlikely(bret->status == BLKIF_RSP_EOPNOTSUPP)) {
+ struct request_queue *rq = info->rq;
+ printk(KERN_WARNING "blkfront: %s: discard op failed\n",
+ info->gd->disk_name);
+ error = -EOPNOTSUPP;
+ info->feature_discard = 0;
+ queue_flag_clear(QUEUE_FLAG_DISCARD, rq);
+ }
+ __blk_end_request_all(req, error);
+ break;
case BLKIF_OP_FLUSH_DISKCACHE:
case BLKIF_OP_WRITE_BARRIER:
if (unlikely(bret->status == BLKIF_RSP_EOPNOTSUPP)) {
@@ -1098,6 +1129,33 @@
bdput(bdev);
}
+static void blkfront_setup_discard(struct blkfront_info *info)
+{
+ int err;
+ char *type;
+ unsigned int discard_granularity;
+ unsigned int discard_alignment;
+
+ type = xenbus_read(XBT_NIL, info->xbdev->otherend, "type", NULL);
+ if (IS_ERR(type))
+ return;
+
+ if (strncmp(type, "phy", 3) == 0) {
+ err = xenbus_gather(XBT_NIL, info->xbdev->otherend,
+ "discard-granularity", "%u", &discard_granularity,
+ "discard-alignment", "%u", &discard_alignment,
+ NULL);
+ if (!err) {
+ info->feature_discard = 1;
+ info->discard_granularity = discard_granularity;
+ info->discard_alignment = discard_alignment;
+ }
+ } else if (strncmp(type, "file", 4) == 0)
+ info->feature_discard = 1;
+
+ kfree(type);
+}
+
/*
* Invoked when the backend is finally 'ready' (and has told produced
* the details about the physical device - #sectors, size, etc).
@@ -1108,7 +1166,7 @@
unsigned long sector_size;
unsigned int binfo;
int err;
- int barrier, flush;
+ int barrier, flush, discard;
switch (info->connected) {
case BLKIF_STATE_CONNECTED:
@@ -1178,7 +1236,14 @@
info->feature_flush = REQ_FLUSH;
info->flush_op = BLKIF_OP_FLUSH_DISKCACHE;
}
-
+
+ err = xenbus_gather(XBT_NIL, info->xbdev->otherend,
+ "feature-discard", "%d", &discard,
+ NULL);
+
+ if (!err && discard)
+ blkfront_setup_discard(info);
+
err = xlvbd_alloc_gendisk(sectors, info, binfo, sector_size);
if (err) {
xenbus_dev_fatal(info->xbdev, err, "xlvbd_add at %s",
@@ -1385,6 +1450,8 @@
static int __init xlblk_init(void)
{
+ int ret;
+
if (!xen_domain())
return -ENODEV;
@@ -1394,7 +1461,13 @@
return -ENODEV;
}
- return xenbus_register_frontend(&blkfront);
+ ret = xenbus_register_frontend(&blkfront);
+ if (ret) {
+ unregister_blkdev(XENVBD_MAJOR, DEV_NAME);
+ return ret;
+ }
+
+ return 0;
}
module_init(xlblk_init);
diff --git a/include/xen/interface/io/blkif.h b/include/xen/interface/io/blkif.h
index 3d5d6db..9324488 100644
--- a/include/xen/interface/io/blkif.h
+++ b/include/xen/interface/io/blkif.h
@@ -57,6 +57,36 @@
* "feature-flush-cache" node!
*/
#define BLKIF_OP_FLUSH_DISKCACHE 3
+
+/*
+ * Recognised only if "feature-discard" is present in backend xenbus info.
+ * The "feature-discard" node contains a boolean indicating whether trim
+ * (ATA) or unmap (SCSI) - conviently called discard requests are likely
+ * to succeed or fail. Either way, a discard request
+ * may fail at any time with BLKIF_RSP_EOPNOTSUPP if it is unsupported by
+ * the underlying block-device hardware. The boolean simply indicates whether
+ * or not it is worthwhile for the frontend to attempt discard requests.
+ * If a backend does not recognise BLKIF_OP_DISCARD, it should *not*
+ * create the "feature-discard" node!
+ *
+ * Discard operation is a request for the underlying block device to mark
+ * extents to be erased. However, discard does not guarantee that the blocks
+ * will be erased from the device - it is just a hint to the device
+ * controller that these blocks are no longer in use. What the device
+ * controller does with that information is left to the controller.
+ * Discard operations are passed with sector_number as the
+ * sector index to begin discard operations at and nr_sectors as the number of
+ * sectors to be discarded. The specified sectors should be discarded if the
+ * underlying block device supports trim (ATA) or unmap (SCSI) operations,
+ * or a BLKIF_RSP_EOPNOTSUPP should be returned.
+ * More information about trim/unmap operations at:
+ * http://t13.org/Documents/UploadedDocuments/docs2008/
+ * e07154r6-Data_Set_Management_Proposal_for_ATA-ACS2.doc
+ * http://www.seagate.com/staticfiles/support/disc/manuals/
+ * Interface%20manuals/100293068c.pdf
+ */
+#define BLKIF_OP_DISCARD 5
+
/*
* Maximum scatter/gather segments per request.
* This is carefully chosen so that sizeof(struct blkif_ring) <= PAGE_SIZE.
@@ -74,6 +104,11 @@
} seg[BLKIF_MAX_SEGMENTS_PER_REQUEST];
};
+struct blkif_request_discard {
+ blkif_sector_t sector_number;
+ uint64_t nr_sectors;
+};
+
struct blkif_request {
uint8_t operation; /* BLKIF_OP_??? */
uint8_t nr_segments; /* number of segments */
@@ -81,6 +116,7 @@
uint64_t id; /* private guest value, echoed in resp */
union {
struct blkif_request_rw rw;
+ struct blkif_request_discard discard;
} u;
};