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nvmet: add simple file backed ns support
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This patch adds simple file backed namespace support for NVMeOF target.

The new file io-cmd-file.c is responsible for handling the code for I/O
commands when ns is file backed. Also, we introduce mempools based slow
path using sync I/Os for file backed ns to ensure forward progress under
reclaim.

The old block device based implementation is moved to io-cmd-bdev.c and
use a "nvmet_bdev_" symbol prefix.  The enable/disable calls are also
move into the respective files.

Signed-off-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
[hch: updated changelog, fixed double req->ns lookup in bdev case]
Signed-off-by: Christoph Hellwig <hch@lst.de>
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Chaitanya Kulkarni authored and Christoph Hellwig committed May 25, 2018
1 parent 618cff4 commit d5eff33
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Showing 6 changed files with 413 additions and 52 deletions.
4 changes: 2 additions & 2 deletions drivers/nvme/target/Makefile
View file
Original file line number Diff line number Diff line change
Expand Up @@ -6,8 +6,8 @@ obj-$(CONFIG_NVME_TARGET_RDMA) += nvmet-rdma.o
obj-$(CONFIG_NVME_TARGET_FC) += nvmet-fc.o
obj-$(CONFIG_NVME_TARGET_FCLOOP) += nvme-fcloop.o

nvmet-y += core.o configfs.o admin-cmd.o io-cmd.o fabrics-cmd.o \
discovery.o
nvmet-y += core.o configfs.o admin-cmd.o fabrics-cmd.o \
discovery.o io-cmd-file.o io-cmd-bdev.o
nvme-loop-y += loop.o
nvmet-rdma-y += rdma.o
nvmet-fc-y += fc.o
Expand Down
8 changes: 8 additions & 0 deletions drivers/nvme/target/admin-cmd.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -45,6 +45,10 @@ static u16 nvmet_get_smart_log_nsid(struct nvmet_req *req,
return NVME_SC_INVALID_NS;
}

/* we don't have the right data for file backed ns */
if (!ns->bdev)
goto out;

host_reads = part_stat_read(ns->bdev->bd_part, ios[READ]);
data_units_read = part_stat_read(ns->bdev->bd_part, sectors[READ]);
host_writes = part_stat_read(ns->bdev->bd_part, ios[WRITE]);
Expand All @@ -54,6 +58,7 @@ static u16 nvmet_get_smart_log_nsid(struct nvmet_req *req,
put_unaligned_le64(data_units_read, &slog->data_units_read[0]);
put_unaligned_le64(host_writes, &slog->host_writes[0]);
put_unaligned_le64(data_units_written, &slog->data_units_written[0]);
out:
nvmet_put_namespace(ns);

return NVME_SC_SUCCESS;
Expand All @@ -71,6 +76,9 @@ static u16 nvmet_get_smart_log_all(struct nvmet_req *req,

rcu_read_lock();
list_for_each_entry_rcu(ns, &ctrl->subsys->namespaces, dev_link) {
/* we don't have the right data for file backed ns */
if (!ns->bdev)
continue;
host_reads += part_stat_read(ns->bdev->bd_part, ios[READ]);
data_units_read +=
part_stat_read(ns->bdev->bd_part, sectors[READ]);
Expand Down
50 changes: 33 additions & 17 deletions drivers/nvme/target/core.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -271,6 +271,12 @@ void nvmet_put_namespace(struct nvmet_ns *ns)
percpu_ref_put(&ns->ref);
}

static void nvmet_ns_dev_disable(struct nvmet_ns *ns)
{
nvmet_bdev_ns_disable(ns);
nvmet_file_ns_disable(ns);
}

int nvmet_ns_enable(struct nvmet_ns *ns)
{
struct nvmet_subsys *subsys = ns->subsys;
Expand All @@ -281,23 +287,16 @@ int nvmet_ns_enable(struct nvmet_ns *ns)
if (ns->enabled)
goto out_unlock;

ns->bdev = blkdev_get_by_path(ns->device_path, FMODE_READ | FMODE_WRITE,
NULL);
if (IS_ERR(ns->bdev)) {
pr_err("failed to open block device %s: (%ld)\n",
ns->device_path, PTR_ERR(ns->bdev));
ret = PTR_ERR(ns->bdev);
ns->bdev = NULL;
ret = nvmet_bdev_ns_enable(ns);
if (ret)
ret = nvmet_file_ns_enable(ns);
if (ret)
goto out_unlock;
}

ns->size = i_size_read(ns->bdev->bd_inode);
ns->blksize_shift = blksize_bits(bdev_logical_block_size(ns->bdev));

ret = percpu_ref_init(&ns->ref, nvmet_destroy_namespace,
0, GFP_KERNEL);
if (ret)
goto out_blkdev_put;
goto out_dev_put;

if (ns->nsid > subsys->max_nsid)
subsys->max_nsid = ns->nsid;
Expand Down Expand Up @@ -328,9 +327,8 @@ int nvmet_ns_enable(struct nvmet_ns *ns)
out_unlock:
mutex_unlock(&subsys->lock);
return ret;
out_blkdev_put:
blkdev_put(ns->bdev, FMODE_WRITE|FMODE_READ);
ns->bdev = NULL;
out_dev_put:
nvmet_ns_dev_disable(ns);
goto out_unlock;
}

Expand Down Expand Up @@ -366,8 +364,7 @@ void nvmet_ns_disable(struct nvmet_ns *ns)
list_for_each_entry(ctrl, &subsys->ctrls, subsys_entry)
nvmet_add_async_event(ctrl, NVME_AER_TYPE_NOTICE, 0, 0);

if (ns->bdev)
blkdev_put(ns->bdev, FMODE_WRITE|FMODE_READ);
nvmet_ns_dev_disable(ns);
out_unlock:
mutex_unlock(&subsys->lock);
}
Expand Down Expand Up @@ -499,6 +496,25 @@ int nvmet_sq_init(struct nvmet_sq *sq)
}
EXPORT_SYMBOL_GPL(nvmet_sq_init);

static u16 nvmet_parse_io_cmd(struct nvmet_req *req)
{
struct nvme_command *cmd = req->cmd;
u16 ret;

ret = nvmet_check_ctrl_status(req, cmd);
if (unlikely(ret))
return ret;

req->ns = nvmet_find_namespace(req->sq->ctrl, cmd->rw.nsid);
if (unlikely(!req->ns))
return NVME_SC_INVALID_NS | NVME_SC_DNR;

if (req->ns->file)
return nvmet_file_parse_io_cmd(req);
else
return nvmet_bdev_parse_io_cmd(req);
}

bool nvmet_req_init(struct nvmet_req *req, struct nvmet_cq *cq,
struct nvmet_sq *sq, const struct nvmet_fabrics_ops *ops)
{
Expand Down
75 changes: 44 additions & 31 deletions drivers/nvme/target/io-cmd.c → drivers/nvme/target/io-cmd-bdev.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -16,27 +16,49 @@
#include <linux/module.h>
#include "nvmet.h"

int nvmet_bdev_ns_enable(struct nvmet_ns *ns)
{
int ret;

ns->bdev = blkdev_get_by_path(ns->device_path,
FMODE_READ | FMODE_WRITE, NULL);
if (IS_ERR(ns->bdev)) {
ret = PTR_ERR(ns->bdev);
if (ret != -ENOTBLK) {
pr_err("failed to open block device %s: (%ld)\n",
ns->device_path, PTR_ERR(ns->bdev));
}
ns->bdev = NULL;
return ret;
}
ns->size = i_size_read(ns->bdev->bd_inode);
ns->blksize_shift = blksize_bits(bdev_logical_block_size(ns->bdev));
return 0;
}

void nvmet_bdev_ns_disable(struct nvmet_ns *ns)
{
if (ns->bdev) {
blkdev_put(ns->bdev, FMODE_WRITE | FMODE_READ);
ns->bdev = NULL;
}
}

static void nvmet_bio_done(struct bio *bio)
{
struct nvmet_req *req = bio->bi_private;

nvmet_req_complete(req,
bio->bi_status ? NVME_SC_INTERNAL | NVME_SC_DNR : 0);

if (bio != &req->inline_bio)
if (bio != &req->b.inline_bio)
bio_put(bio);
}

static inline u32 nvmet_rw_len(struct nvmet_req *req)
{
return ((u32)le16_to_cpu(req->cmd->rw.length) + 1) <<
req->ns->blksize_shift;
}

static void nvmet_execute_rw(struct nvmet_req *req)
static void nvmet_bdev_execute_rw(struct nvmet_req *req)
{
int sg_cnt = req->sg_cnt;
struct bio *bio = &req->inline_bio;
struct bio *bio = &req->b.inline_bio;
struct scatterlist *sg;
sector_t sector;
blk_qc_t cookie;
Expand Down Expand Up @@ -89,9 +111,9 @@ static void nvmet_execute_rw(struct nvmet_req *req)
blk_poll(bdev_get_queue(req->ns->bdev), cookie);
}

static void nvmet_execute_flush(struct nvmet_req *req)
static void nvmet_bdev_execute_flush(struct nvmet_req *req)
{
struct bio *bio = &req->inline_bio;
struct bio *bio = &req->b.inline_bio;

bio_init(bio, req->inline_bvec, ARRAY_SIZE(req->inline_bvec));
bio_set_dev(bio, req->ns->bdev);
Expand All @@ -102,7 +124,7 @@ static void nvmet_execute_flush(struct nvmet_req *req)
submit_bio(bio);
}

static u16 nvmet_discard_range(struct nvmet_ns *ns,
static u16 nvmet_bdev_discard_range(struct nvmet_ns *ns,
struct nvme_dsm_range *range, struct bio **bio)
{
int ret;
Expand All @@ -116,7 +138,7 @@ static u16 nvmet_discard_range(struct nvmet_ns *ns,
return 0;
}

static void nvmet_execute_discard(struct nvmet_req *req)
static void nvmet_bdev_execute_discard(struct nvmet_req *req)
{
struct nvme_dsm_range range;
struct bio *bio = NULL;
Expand All @@ -129,7 +151,7 @@ static void nvmet_execute_discard(struct nvmet_req *req)
if (status)
break;

status = nvmet_discard_range(req->ns, &range, &bio);
status = nvmet_bdev_discard_range(req->ns, &range, &bio);
if (status)
break;
}
Expand All @@ -148,11 +170,11 @@ static void nvmet_execute_discard(struct nvmet_req *req)
}
}

static void nvmet_execute_dsm(struct nvmet_req *req)
static void nvmet_bdev_execute_dsm(struct nvmet_req *req)
{
switch (le32_to_cpu(req->cmd->dsm.attributes)) {
case NVME_DSMGMT_AD:
nvmet_execute_discard(req);
nvmet_bdev_execute_discard(req);
return;
case NVME_DSMGMT_IDR:
case NVME_DSMGMT_IDW:
Expand All @@ -163,7 +185,7 @@ static void nvmet_execute_dsm(struct nvmet_req *req)
}
}

static void nvmet_execute_write_zeroes(struct nvmet_req *req)
static void nvmet_bdev_execute_write_zeroes(struct nvmet_req *req)
{
struct nvme_write_zeroes_cmd *write_zeroes = &req->cmd->write_zeroes;
struct bio *bio = NULL;
Expand All @@ -189,36 +211,27 @@ static void nvmet_execute_write_zeroes(struct nvmet_req *req)
}
}

u16 nvmet_parse_io_cmd(struct nvmet_req *req)
u16 nvmet_bdev_parse_io_cmd(struct nvmet_req *req)
{
struct nvme_command *cmd = req->cmd;
u16 ret;

ret = nvmet_check_ctrl_status(req, cmd);
if (unlikely(ret))
return ret;

req->ns = nvmet_find_namespace(req->sq->ctrl, cmd->rw.nsid);
if (unlikely(!req->ns))
return NVME_SC_INVALID_NS | NVME_SC_DNR;

switch (cmd->common.opcode) {
case nvme_cmd_read:
case nvme_cmd_write:
req->execute = nvmet_execute_rw;
req->execute = nvmet_bdev_execute_rw;
req->data_len = nvmet_rw_len(req);
return 0;
case nvme_cmd_flush:
req->execute = nvmet_execute_flush;
req->execute = nvmet_bdev_execute_flush;
req->data_len = 0;
return 0;
case nvme_cmd_dsm:
req->execute = nvmet_execute_dsm;
req->execute = nvmet_bdev_execute_dsm;
req->data_len = (le32_to_cpu(cmd->dsm.nr) + 1) *
sizeof(struct nvme_dsm_range);
return 0;
case nvme_cmd_write_zeroes:
req->execute = nvmet_execute_write_zeroes;
req->execute = nvmet_bdev_execute_write_zeroes;
return 0;
default:
pr_err("unhandled cmd %d on qid %d\n", cmd->common.opcode,
Expand Down
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