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Re: [PATCH v2 1/2] file-posix: add the tracking of the zones wp
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From: |
Sam Li |
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Subject: |
Re: [PATCH v2 1/2] file-posix: add the tracking of the zones wp |
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Date: |
Wed, 5 Oct 2022 16:30:51 +0800 |
Damien Le Moal <damien.lemoal@opensource.wdc.com> 于2022年10月5日周三 15:34写道：
>
> On 10/5/22 10:44, Damien Le Moal wrote:
> > On 9/29/22 18:31, Sam Li wrote:
> >> Since Linux doesn't have a user API to issue zone append operations to
> >> zoned devices from user space, the file-posix driver is modified to add
> >> zone append emulation using regular writes. To do this, the file-posix
> >> driver tracks the wp location of all zones of the device. It uses an
> >> array of uint64_t. The most significant bit of each wp location indicates
> >> if the zone type is sequential write required.
> >>
> >> The zones wp can be changed due to the following operations issued:
> >> - zone reset: change the wp to the start offset of that zone
> >> - zone finish: change to the end location of that zone
> >> - write to a zone
> >> - zone append
> >>
> >> Signed-off-by: Sam Li <faithilikerun@gmail.com>
>
> Replying to myself to add some comments that I forgot.
>
> >> ---
> >> block/file-posix.c | 138 ++++++++++++++++++++++++++++++-
> >> include/block/block-common.h | 16 ++++
> >> include/block/block_int-common.h | 5 ++
> >> include/block/raw-aio.h | 4 +-
> >> 4 files changed, 159 insertions(+), 4 deletions(-)
> >>
> >> diff --git a/block/file-posix.c b/block/file-posix.c
> >> index 73656d87f2..33e81ac112 100755
> >> --- a/block/file-posix.c
> >> +++ b/block/file-posix.c
> >> @@ -206,6 +206,8 @@ typedef struct RawPosixAIOData {
> >> struct {
> >> struct iovec *iov;
> >> int niov;
> >> + int64_t *append_sector;
> >> + BlockZoneWps *wps;
> >> } io;
> >> struct {
> >> uint64_t cmd;
> >> @@ -1332,6 +1334,59 @@ static int hdev_get_max_segments(int fd, struct
> >> stat *st) {
> >> #endif
> >> }
> >>
> >> +#if defined(CONFIG_BLKZONED)
> >> +static int report_zone_wp(int64_t offset, int fd, BlockZoneWps *wps,
> >> + unsigned int nrz) {
> >
> > Maybe rename this to get_zones_wp() ?
> >
> >> + struct blk_zone *blkz;
> >> + int64_t rep_size;
> >> + int64_t sector = offset >> BDRV_SECTOR_BITS;
> >> + int ret, n = 0, i = 0;
> >> +
> >> + rep_size = sizeof(struct blk_zone_report) + nrz * sizeof(struct
> >> blk_zone);
> >> + g_autofree struct blk_zone_report *rep = NULL;
> >
> > To be cleaner, move this declaration above with the others ?
> >
> >> + rep = g_malloc(rep_size);
> >> +
> >> + blkz = (struct blk_zone *)(rep + 1);
> >> + while (n < nrz) {
> >> + memset(rep, 0, rep_size);
> >> + rep->sector = sector;
> >> + rep->nr_zones = nrz - n;
> >> +
> >> + do {
> >> + ret = ioctl(fd, BLKREPORTZONE, rep);
> >> + } while (ret != 0 && errno == EINTR);
> >> + if (ret != 0) {
> >> + error_report("%d: ioctl BLKREPORTZONE at %" PRId64 " failed
> >> %d",
> >> + fd, offset, errno);
> >> + return -errno;
> >> + }
> >> +
> >> + if (!rep->nr_zones) {
> >> + break;
> >> + }
> >> +
> >> + for (i = 0; i < rep->nr_zones; i++, n++) {
> >> + wps->wp[i] = blkz[i].wp << BDRV_SECTOR_BITS;
> >> + sector = blkz[i].start + blkz[i].len;
> >> +
> >> + /*
> >> + * In the wp tracking, it only cares if the zone type is
> >> sequential
> >> + * writes required so that the wp can advance to the right
> >> location.
> >
> > Or sequential write preferred (host aware case)
> >
> >> + * Instead of the type of zone_type which is an 8-bit unsigned
> >> + * integer, use the first most significant bits of the wp
> >> location
> >> + * to indicate the zone type: 0 for SWR zones and 1 for the
> >> + * others.
> >> + */
> >> + if (!(blkz[i].type & BLK_ZONE_TYPE_SEQWRITE_REQ)) {
> >
> > This should be:
> >
> > if (blkz[i].type != BLK_ZONE_TYPE_CONVENTIONAL) {
> >
> > Note that the type field is not a bit-field. So you must compare values
> > instead of doing bit operations.
> >
> >> + wps->wp[i] += (uint64_t)1 << 63;
> >
> > You can simplify this:
> >
> > wps->wp[i] |= 1ULL << 63;
> >
> > Overall, I would rewrite this like this:
> >
> > for (i = 0; i < rep->nr_zones; i++, n++) {
> > /*
> > * The wp tracking cares only about sequential write required
> > * and sequential write preferred zones so that the wp can
> > * advance to the right location.
> > * Use the most significant bit of the wp location
> > * to indicate the zone type: 0 for SWR zones and 1 for
> > * conventional zones.
> > */
> > if (blkz[i].type == BLK_ZONE_TYPE_CONVENTIONAL) {
> > wps->wp[i] = 1ULL << 63;
> > else
> > wps->wp[i] = blkz[i].wp << BDRV_SECTOR_BITS;
> > }
> > sector = blkz[i - 1].start + blkz[i - 1].len;
> >
> > Which I think is a lot simpler.
> >
> >> + }
> >> + }
> >> + }
> >> +
> >> + return 0;
> >> +}
> >> +#endif
> >> +
> >> static void raw_refresh_limits(BlockDriverState *bs, Error **errp)
> >> {
> >> BDRVRawState *s = bs->opaque;
> >> @@ -1415,6 +1470,20 @@ static void raw_refresh_limits(BlockDriverState
> >> *bs, Error **errp)
> >> error_report("Invalid device capacity %" PRId64 " bytes ",
> >> bs->bl.capacity);
> >> return;
> >> }
> >> +
> >> + ret = get_sysfs_long_val(&st, "physical_block_size");
> >> + if (ret >= 0) {
> >> + bs->bl.write_granularity = ret;
> >> + }
> >
> > This change seems unrelated to the wp tracking. Should this be moved to a
> > different patch ?
> >
> >> +
> >> + bs->bl.wps = g_malloc(sizeof(BlockZoneWps) + sizeof(int64_t) *
> >> ret);
> >> + qemu_mutex_init(&bs->bl.wps->lock);
> >
> > Move this initialization after the if block. Doing so, you do not need to
> > call mutex destroy in case of error.
> >
> >> + if (report_zone_wp(0, s->fd, bs->bl.wps, ret) < 0 ) {
> >> + error_report("report wps failed");
> >> + qemu_mutex_destroy(&bs->bl.wps->lock);
> >> + g_free(bs->bl.wps);
> >> + return;
> >> + }
> >> }
> >> }
> >>
> >> @@ -1582,7 +1651,7 @@ static ssize_t
> >> handle_aiocb_rw_vector(RawPosixAIOData *aiocb)
> >> ssize_t len;
> >>
> >> do {
> >> - if (aiocb->aio_type & QEMU_AIO_WRITE)
> >> + if (aiocb->aio_type & (QEMU_AIO_WRITE | QEMU_AIO_ZONE_APPEND))
> >> len = qemu_pwritev(aiocb->aio_fildes,
> >> aiocb->io.iov,
> >> aiocb->io.niov,
> >> @@ -1612,7 +1681,7 @@ static ssize_t
> >> handle_aiocb_rw_linear(RawPosixAIOData *aiocb, char *buf)
> >> ssize_t len;
> >>
> >> while (offset < aiocb->aio_nbytes) {
> >> - if (aiocb->aio_type & QEMU_AIO_WRITE) {
> >> + if (aiocb->aio_type & (QEMU_AIO_WRITE | QEMU_AIO_ZONE_APPEND)) {
> >> len = pwrite(aiocb->aio_fildes,
> >> (const char *)buf + offset,
> >> aiocb->aio_nbytes - offset,
> >> @@ -1705,7 +1774,7 @@ static int handle_aiocb_rw(void *opaque)
> >> }
> >>
> >> nbytes = handle_aiocb_rw_linear(aiocb, buf);
> >> - if (!(aiocb->aio_type & QEMU_AIO_WRITE)) {
> >> + if (!(aiocb->aio_type & (QEMU_AIO_WRITE | QEMU_AIO_ZONE_APPEND))) {
> >> char *p = buf;
> >> size_t count = aiocb->aio_nbytes, copy;
> >> int i;
> >> @@ -1726,6 +1795,23 @@ static int handle_aiocb_rw(void *opaque)
> >>
> >> out:
> >> if (nbytes == aiocb->aio_nbytes) {
> >> +#if defined(CONFIG_BLKZONED)
> >> + if (aiocb->aio_type & (QEMU_AIO_WRITE | QEMU_AIO_ZONE_APPEND)) {
> >> + BlockZoneWps *wps = aiocb->io.wps;
> >
> > Why adding this pointer to the aiocb struct ? You can get the array from
> > aiocb->bs->bl.wps, no ?
> >
> >> + int index = aiocb->aio_offset / aiocb->bs->bl.zone_size;
> >> + if (wps) {
> >> + if (BDRV_ZT_IS_SWR(wps->wp[index])) {
> >> + qemu_mutex_lock(&wps->lock);
> >> + wps->wp[index] += aiocb->aio_nbytes;
> >> + qemu_mutex_unlock(&wps->lock);
> >> + }
> >> +
> >> + if (aiocb->aio_type & QEMU_AIO_ZONE_APPEND) {
> >> + *aiocb->io.append_sector = wps->wp[index] >>
> >> BDRV_SECTOR_BITS;
> >
> > Bug: the append sector must be the first sector written, not the wp
> > (sector following the last written sector). So this must be done *before*
> > advancing the wp.
> >
> > You need to have wps->lock held here too since you are reading
> > wps->wp[index]. So the mutex lock/unlock needs to be around the 2 hunks
> > under "if (wps) {". Also, given that there cannot be any zone append
> > issued to conventional zones (they will fail), you can simplify:
> >
> > if (wps) {
> > qemu_mutex_lock(&wps->lock);
> > if (BDRV_ZT_IS_SWR(wps->wp[index])) {
> > if (aiocb->aio_type & QEMU_AIO_ZONE_APPEND) {
> > *aiocb->io.append_sector =
> > wps->wp[index] >> BDRV_SECTOR_BITS;
> > }
> > wps->wp[index] += aiocb->aio_nbytes;
> > }
> > qemu_mutex_unlock(&wps->lock);
> > }
> >
> > Now the last problem with this code is sequential write preferred zones.
> > For these, the write may actually be overwriting sectors that have already
> > been written, meaning that the wp may not necessarilly need to be
> > advanced. You can handle that case together with SWR case simply like this:
> >
> > if (wps) {
> > qemu_mutex_lock(&wps->lock);
> > if (BDRV_ZT_IS_SWR(wps->wp[index])) {
> > uint64_t wend_offset =
> > aiocb->aio_offset + aiocb->aio_nbytes;
> >
> > if (aiocb->aio_type & QEMU_AIO_ZONE_APPEND) {
> > *aiocb->io.append_sector =
> > wps->wp[index] >> BDRV_SECTOR_BITS;
> > }
> >
> > /* Advance the wp if needed */
> > if (wend_offset > wps->wp[index])
> > wps->wp[index] = wend_offset;
> > }
> > qemu_mutex_unlock(&wps->lock);
> > }
> >
>
> Note that you should not increment the wp if the zone is already full. But
> for such case, since write and zone append commands will fail, you can
> fail them immediately.
>
> >> + }
> >> + }
> >> + }
> >> +#endif
> >> return 0;
> >> } else if (nbytes >= 0 && nbytes < aiocb->aio_nbytes) {
> >> if (aiocb->aio_type & QEMU_AIO_WRITE) {
> >> @@ -1737,6 +1823,19 @@ out:
> >> }
> >> } else {
> >> assert(nbytes < 0);
> >> +#if defined(CONFIG_BLKZONED)
> >> + if (aiocb->aio_type == QEMU_AIO_ZONE_APPEND) {
> >
> > Why do this only for zone append ? Regular write error also need a refresh
> > of the zone wp.
> >
> >> + qemu_mutex_lock(&aiocb->bs->bl.wps->lock);
> >> + if (report_zone_wp(0, aiocb->aio_fildes, aiocb->bs->bl.wps,
> >> + aiocb->bs->bl.nr_zones) < 0) {
> >> + error_report("report zone wp failed");
> >> + qemu_mutex_destroy(&aiocb->bs->bl.wps->lock);
> >> + g_free(aiocb->bs->bl.wps);
> >> + return -EINVAL;
> >> + }
> >> + qemu_mutex_unlock(&aiocb->bs->bl.wps->lock);
> >
> > This really needs to be a helper function, e.g. update_zone_wp() or
> > something like this. Aslo, why nuke the entire zone array if the refresh
> > for this zone fails ? You could simply leave it as is. The next write may
> > again fail and another attempt at refreshing it done.
> >
> >> + }
> >> +#endif
> >> return nbytes;
> >> }
> >> }
> >> @@ -2027,12 +2126,16 @@ static int handle_aiocb_zone_report(void *opaque) {
> >> static int handle_aiocb_zone_mgmt(void *opaque) {
> >> #if defined(CONFIG_BLKZONED)
> >> RawPosixAIOData *aiocb = opaque;
> >> + BlockDriverState *bs = aiocb->bs;
> >> int fd = aiocb->aio_fildes;
> >> int64_t sector = aiocb->aio_offset / 512;
> >> int64_t nr_sectors = aiocb->aio_nbytes / 512;
> >> struct blk_zone_range range;
> >> int ret;
> >>
> >> + BlockZoneWps *wps = bs->bl.wps;
> >> + int index = aiocb->aio_offset / bs->bl.zone_size;
> >> +
> >> /* Execute the operation */
> >> range.sector = sector;
> >> range.nr_sectors = nr_sectors;
> >> @@ -2045,6 +2148,22 @@ static int handle_aiocb_zone_mgmt(void *opaque) {
> >> errno);
> >> return -errno;
> >> }
> >> +
> >> + if (aiocb->zone_mgmt.all) {
>
> This case should be integrated into the
> if (aiocb->zone_mgmt.zone_op == BLKRESETZONE)
The purpose of this all flag is to pass down the RESET_ALL request to
the file-posix so that it can reset t write pointers of all zones.
>
> >> + for (int i = 0; i < bs->bl.nr_zones; ++i) {
> >> + qemu_mutex_lock(&wps->lock);
> >> + wps->wp[i] = i * bs->bl.zone_size;
>
> You need to test the zone type bit and only change SWR or SWP zones.
>
> >> + qemu_mutex_unlock(&wps->lock);
> >> + }
> >> + } else if (aiocb->zone_mgmt.zone_op == BLKRESETZONE) {
> >> + qemu_mutex_lock(&wps->lock);
> >> + wps->wp[index] = aiocb->aio_offset;
> >> + qemu_mutex_unlock(&wps->lock);
> >> + } else if (aiocb->zone_mgmt.zone_op == BLKFINISHZONE) {
> >> + qemu_mutex_lock(&wps->lock);
> >> + wps->wp[index] = aiocb->aio_offset + bs->bl.zone_size;
> >
> > This may be the last zone of the device, which may be smaller. So you need
> > to check that here. Same for the first case for reset all: you need to
> > handle the smaller last zone if there is one.
>
> You should fail any zone management commnand targetting a conventional
> zone. You are not checking that.
>
> Also, you can avoid issuing commands by testing if a zone is already full
> (no need to issue finish command) or empty (no need to do a reset).
Maybe the type check can be done before issuing the request and the
device can return VIRTIO_BLK_S_ZONE_INVALID_CMD to finish it.
The simplest way to do the state check I think is to compare the wp to
the start/end sector which can tell us if the zone is empty or full.
Therefore it should be done in the raw_co_zone_mgmt().
Thanks for reviewing! I can send the revision very soon.
>
> >
> >> + qemu_mutex_unlock(&wps->lock);
> >> + }
> >
> > Instead of the lock/unlock for each case here, take the mutex lock before
> > the if () and unlock it after it. Less lines :)
> >
> > Also, if the zone management command fails, you need to do a report zones
> > and refresh the wps array.
> >
> >> return ret;
> >> #else
> >> return -ENOTSUP;
> >> @@ -2355,6 +2474,8 @@ static int coroutine_fn raw_co_prw(BlockDriverState
> >> *bs, uint64_t offset,
> >> },
> >> };
> >>
> >> + BlockZoneWps *wps = bs->bl.wps;
> >> + acb.io.wps = wps;
> >
> > You do not need the pws variable. Simply do:
> >
> > acb.io.wps = bs->bl.wps;
> >
> >> assert(qiov->size == bytes);
> >> return raw_thread_pool_submit(bs, handle_aiocb_rw, &acb);
> >> }
> >> @@ -2465,6 +2586,12 @@ static void raw_close(BlockDriverState *bs)
> >> BDRVRawState *s = bs->opaque;
> >>
> >> if (s->fd >= 0) {
> >> +#if defined(CONFIG_BLKZONED)
> >> + if (bs->bl.wps) {
> >> + qemu_mutex_destroy(&bs->bl.wps->lock);
> >> + g_free(bs->bl.wps);
> >> + }
> >> +#endif
> >> qemu_close(s->fd);
> >> s->fd = -1;
> >> }
> >> @@ -3299,6 +3426,11 @@ static int coroutine_fn
> >> raw_co_zone_mgmt(BlockDriverState *bs, BlockZoneOp op,
> >> zone_op_name = "BLKRESETZONE";
> >> zone_op = BLKRESETZONE;
> >> break;
> >> + case BLK_ZO_RESET_ALL:
> >> + zone_op_name = "BLKRESETZONE";
> >> + zone_op = BLKRESETZONE;
> >> + is_all = true;
> >> + break;
> >
> > This change seems unrelated to the wp tracking. Different patch ?
> >
> >> default:
> >> g_assert_not_reached();
> >> }
> >> diff --git a/include/block/block-common.h b/include/block/block-common.h
> >> index 8efb6b0c43..43bfc484eb 100644
> >> --- a/include/block/block-common.h
> >> +++ b/include/block/block-common.h
> >> @@ -58,6 +58,7 @@ typedef enum BlockZoneOp {
> >> BLK_ZO_CLOSE,
> >> BLK_ZO_FINISH,
> >> BLK_ZO_RESET,
> >> + BLK_ZO_RESET_ALL,
> >
> > same here. Adding reset all support should be a different patch.
> >> } BlockZoneOp;
> >>
> >> typedef enum BlockZoneModel {
> >> @@ -96,6 +97,14 @@ typedef struct BlockZoneDescriptor {
> >> BlockZoneCondition cond;
> >> } BlockZoneDescriptor;
> >>
> >> +/*
> >> + * Track write pointers of a zone in bytes.
> >> + */
> >> +typedef struct BlockZoneWps {
> >> + QemuMutex lock;
> >> + uint64_t wp[];
> >> +} BlockZoneWps;
> >> +
> >> typedef struct BlockDriverInfo {
> >> /* in bytes, 0 if irrelevant */
> >> int cluster_size;
> >> @@ -209,6 +218,13 @@ typedef enum {
> >> #define BDRV_SECTOR_BITS 9
> >> #define BDRV_SECTOR_SIZE (1ULL << BDRV_SECTOR_BITS)
> >>
> >> +/*
> >> + * Get the first most significant bit of WP. If it is zero, then
> >> + * the zone type is SWR.
> >> + */
> >> +#define BDRV_ZT_IS_SWR(WP) ((WP & 0x8000000000000000) == 0) ? (true) :
> >> \
> >> + (false)
> >
> > Simplify:
> >
> > #define BDRV_ZT_IS_SWR(wp) (!((wp) & (1ULL << 63))
> >
> > But since this must be used for both SWR and SWP zones, I would reverse
> > this into:
> >
> > #define BDRV_ZONE_IS_CONV(wp) ((wp) & (1ULL << 63))
> >
> > Which is a lot simpler.
> >
> >> +
> >> #define BDRV_REQUEST_MAX_SECTORS MIN_CONST(SIZE_MAX >> BDRV_SECTOR_BITS, \
> >> INT_MAX >> BDRV_SECTOR_BITS)
> >> #define BDRV_REQUEST_MAX_BYTES (BDRV_REQUEST_MAX_SECTORS <<
> >> BDRV_SECTOR_BITS)
> >> diff --git a/include/block/block_int-common.h
> >> b/include/block/block_int-common.h
> >> index 37dddc603c..59c2d1316d 100644
> >> --- a/include/block/block_int-common.h
> >> +++ b/include/block/block_int-common.h
> >> @@ -857,6 +857,11 @@ typedef struct BlockLimits {
> >>
> >> /* device capacity expressed in bytes */
> >> int64_t capacity;
> >> +
> >> + /* array of write pointers' location of each zone in the zoned
> >> device. */
> >> + BlockZoneWps *wps;
> >> +
> >> + int64_t write_granularity;
> >> } BlockLimits;
> >>
> >> typedef struct BdrvOpBlocker BdrvOpBlocker;
> >> diff --git a/include/block/raw-aio.h b/include/block/raw-aio.h
> >> index 3d26929cdd..f13cc1887b 100644
> >> --- a/include/block/raw-aio.h
> >> +++ b/include/block/raw-aio.h
> >> @@ -31,6 +31,7 @@
> >> #define QEMU_AIO_TRUNCATE 0x0080
> >> #define QEMU_AIO_ZONE_REPORT 0x0100
> >> #define QEMU_AIO_ZONE_MGMT 0x0200
> >> +#define QEMU_AIO_ZONE_APPEND 0x0400
> >> #define QEMU_AIO_TYPE_MASK \
> >> (QEMU_AIO_READ | \
> >> QEMU_AIO_WRITE | \
> >> @@ -41,7 +42,8 @@
> >> QEMU_AIO_COPY_RANGE | \
> >> QEMU_AIO_TRUNCATE | \
> >> QEMU_AIO_ZONE_REPORT | \
> >> - QEMU_AIO_ZONE_MGMT)
> >> + QEMU_AIO_ZONE_MGMT | \
> >> + QEMU_AIO_ZONE_APPEND)
> >
> > This should be introduced in patch 2. This patch should be only about zone
> > wp tracking with regular writes and zone management ops. The second patch
> > can implement zone append emulation thanks to this patch. So separate.
> >
> >>
> >> /* AIO flags */
> >> #define QEMU_AIO_MISALIGNED 0x1000
> >
>
> --
> Damien Le Moal
> Western Digital Research
>