diff options
Diffstat (limited to 'drivers/block/xen-blkback/blkback.c')
| -rw-r--r-- | drivers/block/xen-blkback/blkback.c | 130 |
1 files changed, 109 insertions, 21 deletions
diff --git a/drivers/block/xen-blkback/blkback.c b/drivers/block/xen-blkback/blkback.c index 1540792b1e54..15ec4db194d1 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" + " | 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 @@ 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); +} + +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 @@ static void __end_block_io_op(struct pending_req *pending_req, int error) 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 @@ static void __end_block_io_op(struct pending_req *pending_req, int error) 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 @@ do_block_io_op(struct xen_blkif *blkif) 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 @@ static int dispatch_rw_block_io(struct xen_blkif *blkif, int i, nbio = 0; int operation; struct blk_plug plug; + bool drain = false; switch (req->operation) { case BLKIF_OP_READ: @@ -559,11 +627,16 @@ static int dispatch_rw_block_io(struct xen_blkif *blkif, 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 @@ 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); @@ -621,16 +695,25 @@ static int dispatch_rw_block_io(struct xen_blkif *blkif, } } + /* 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 @@ 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; + } } /* @@ -685,7 +775,7 @@ static int dispatch_rw_block_io(struct xen_blkif *blkif, 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 @@ static int __init xen_blkif_init(void) 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 @@ static int __init xen_blkif_init(void) 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); |