On Thu, Mar 23, 2023 at 01:19:04PM +0800, 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 conventional zones.
>
> 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 <faithilike...@gmail.com>
> ---
> block/file-posix.c | 168 ++++++++++++++++++++++++++++++-
> include/block/block-common.h | 14 +++
> include/block/block_int-common.h | 5 +
> 3 files changed, 183 insertions(+), 4 deletions(-)
>
> diff --git a/block/file-posix.c b/block/file-posix.c
> index 65efe5147e..0fb425dcae 100644
> --- a/block/file-posix.c
> +++ b/block/file-posix.c
> @@ -1324,6 +1324,85 @@ static int hdev_get_max_segments(int fd, struct stat
> *st)
> #endif
> }
>
> +#if defined(CONFIG_BLKZONED)
> +/*
> + * If the ra (reset_all) flag > 0, then the wp of that zone should be reset
> to
> + * the start sector. Else, take the real wp of the device.
> + */
> +static int get_zones_wp(int fd, BlockZoneWps *wps, int64_t offset,
> + unsigned int nrz, int ra) {
Please use bool for true/false and use clear variable names:
int ra -> bool reset_all
> + struct blk_zone *blkz;
> + size_t rep_size;
> + uint64_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;
> +
> + 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++) {
> + /*
> + * The wp tracking cares only about sequential writes 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/SWP zones and 1 for conventional zones.
> + */
> + if (blkz[i].type == BLK_ZONE_TYPE_CONVENTIONAL) {
> + wps->wp[i] &= 1ULL << 63;
> + } else {
> + switch(blkz[i].cond) {
> + case BLK_ZONE_COND_FULL:
> + case BLK_ZONE_COND_READONLY:
> + /* Zone not writable */
> + wps->wp[i] = (blkz[i].start + blkz[i].len) <<
> BDRV_SECTOR_BITS;
> + break;
> + case BLK_ZONE_COND_OFFLINE:
> + /* Zone not writable nor readable */
> + wps->wp[i] = (blkz[i].start) << BDRV_SECTOR_BITS;
> + break;
> + default:
> + if (ra > 0) {
> + wps->wp[i] = blkz[i].start << BDRV_SECTOR_BITS;
> + } else {
> + wps->wp[i] = blkz[i].wp << BDRV_SECTOR_BITS;
> + }
> + break;
> + }
> + }
> + }
> + sector = blkz[i - 1].start + blkz[i - 1].len;
> + }
> +
> + return 0;
> +}
> +
> +static void update_zones_wp(int fd, BlockZoneWps *wps, int64_t offset,
> + unsigned int nrz) {
QEMU coding style puts the opening curly bracket on a new line:
static void update_zones_wp(int fd, BlockZoneWps *wps, int64_t offset,
unsigned int nrz)
{
> + if (get_zones_wp(fd, wps, offset, nrz, 0) < 0) {
> + error_report("update zone wp failed");
> + }
> +}
> +#endif
> +
> static void raw_refresh_limits(BlockDriverState *bs, Error **errp)
> {
> BDRVRawState *s = bs->opaque;
> @@ -1413,6 +1492,21 @@ static void raw_refresh_limits(BlockDriverState *bs,
> Error **errp)
> if (ret >= 0) {
> bs->bl.max_active_zones = ret;
> }
> +
> + ret = get_sysfs_long_val(&st, "physical_block_size");
> + if (ret >= 0) {
> + bs->bl.write_granularity = ret;
> + }
> +
> + bs->bl.wps = g_malloc(sizeof(BlockZoneWps) +
> + sizeof(int64_t) * bs->bl.nr_zones);
This function can be called multiple times, so the old bs->bl.wps needs
to be freed to avoid a memory leak here.
> + ret = get_zones_wp(s->fd, bs->bl.wps, 0, bs->bl.nr_zones, 0);
> + if (ret < 0) {
> + error_setg_errno(errp, -ret, "report wps failed");
> + g_free(bs->bl.wps);
Please set it to NULL to reduce the risk of a double-free.
> + return;
> + }
> + qemu_co_mutex_init(&bs->bl.wps->colock);
I just noticed there is a problem with keeping the mutex and
heap-allocated wps inside bs.bl. bdrv_refresh_limits does this:
memset(&bs->bl, 0, sizeof(bs->bl));
It would be possible to exclude the wps and mutex from the memset, but
maybe they should be BlockDriverState fields instead. They are not
really limits.
> return;
> }
> out:
> @@ -2338,9 +2432,15 @@ static int coroutine_fn raw_co_prw(BlockDriverState
> *bs, uint64_t offset,
> {
> BDRVRawState *s = bs->opaque;
> RawPosixAIOData acb;
> + int ret;
>
> if (fd_open(bs) < 0)
> return -EIO;
> +#if defined(CONFIG_BLKZONED)
> + if (type & QEMU_AIO_WRITE && bs->bl.wps) {
> + qemu_co_mutex_lock(&bs->bl.wps->colock);
> + }
> +#endif
>
> /*
> * When using O_DIRECT, the request must be aligned to be able to use
> @@ -2354,14 +2454,16 @@ static int coroutine_fn raw_co_prw(BlockDriverState
> *bs, uint64_t offset,
> } else if (s->use_linux_io_uring) {
> LuringState *aio = aio_get_linux_io_uring(bdrv_get_aio_context(bs));
> assert(qiov->size == bytes);
> - return luring_co_submit(bs, aio, s->fd, offset, qiov, type);
> + ret = luring_co_submit(bs, aio, s->fd, offset, qiov, type);
> + goto out;
> #endif
> #ifdef CONFIG_LINUX_AIO
> } else if (s->use_linux_aio) {
> LinuxAioState *aio = aio_get_linux_aio(bdrv_get_aio_context(bs));
> assert(qiov->size == bytes);
> - return laio_co_submit(bs, aio, s->fd, offset, qiov, type,
> + ret = laio_co_submit(bs, aio, s->fd, offset, qiov, type,
> s->aio_max_batch);
> + goto out;
> #endif
> }
>
> @@ -2378,7 +2480,32 @@ static int coroutine_fn raw_co_prw(BlockDriverState
> *bs, uint64_t offset,
> };
>
> assert(qiov->size == bytes);
> - return raw_thread_pool_submit(bs, handle_aiocb_rw, &acb);
> + ret = raw_thread_pool_submit(bs, handle_aiocb_rw, &acb);
> +
> +out:
> +#if defined(CONFIG_BLKZONED)
> + BlockZoneWps *wps = bs->bl.wps;
> + if (ret == 0) {
> + if (type & QEMU_AIO_WRITE && wps && bs->bl.zone_size) {
> + uint64_t *wp = &wps->wp[offset / bs->bl.zone_size];
> + if (!BDRV_ZT_IS_CONV(*wp)) {
> + /* Advance the wp if needed */
> + if (offset + bytes > *wp) {
> + *wp = offset + bytes;
> + }
> + }
> + }
> + } else {
> + if (type & QEMU_AIO_WRITE) {
> + update_zones_wp(s->fd, bs->bl.wps, 0, 1);
> + }
> + }
> +
> + if (type & QEMU_AIO_WRITE && wps) {
> + qemu_co_mutex_unlock(&wps->colock);
> + }
> +#endif
> + return ret;
> }
>
> static int coroutine_fn raw_co_preadv(BlockDriverState *bs, int64_t offset,
> @@ -2486,6 +2613,11 @@ static void raw_close(BlockDriverState *bs)
> BDRVRawState *s = bs->opaque;
>
> if (s->fd >= 0) {
> +#if defined(CONFIG_BLKZONED)
> + if (bs->bl.wps) {
> + g_free(bs->bl.wps);
> + }
The if statement can be replaced with an unconditional
g_free(bs->bl.wps) call. g_free(NULL) is valid and just returns
immediately.
> +#endif
> qemu_close(s->fd);
> s->fd = -1;
> }
> @@ -3283,6 +3415,7 @@ static int coroutine_fn
> raw_co_zone_mgmt(BlockDriverState *bs, BlockZoneOp op,
> const char *op_name;
> unsigned long zo;
> int ret;
> + BlockZoneWps *wps = bs->bl.wps;
> int64_t capacity = bs->total_sectors << BDRV_SECTOR_BITS;
>
> zone_size = bs->bl.zone_size;
> @@ -3300,6 +3433,15 @@ static int coroutine_fn
> raw_co_zone_mgmt(BlockDriverState *bs, BlockZoneOp op,
> return -EINVAL;
> }
>
> + qemu_co_mutex_lock(&wps->colock);
I suggest using:
QEMU_LOCK_GUARD(&wps->colock);
...
or:
WITH_QEMU_LOCK_GUARD(&wps->colock) {
...
}
instead of qemu_co_mutex_lock/unlock().
That way the lock is guaranteed to be unlocked when the function returns
and you don't need to convert the error code paths to use goto.
> + uint32_t i = offset / bs->bl.zone_size;
> + uint64_t *wp = &wps->wp[i];
> + if (BDRV_ZT_IS_CONV(*wp) && len != capacity) {
> + error_report("zone mgmt operations are not allowed for conventional
> zones");
> + ret = -EIO;
> + goto out;
> + }
> +
> switch (op) {
> case BLK_ZO_OPEN:
> op_name = "BLKOPENZONE";
> @@ -3319,7 +3461,8 @@ static int coroutine_fn
> raw_co_zone_mgmt(BlockDriverState *bs, BlockZoneOp op,
> break;
> default:
> error_report("Unsupported zone op: 0x%x", op);
> - return -ENOTSUP;
> + ret = -ENOTSUP;
> + goto out;
> }
>
> acb = (RawPosixAIOData) {
> @@ -3337,10 +3480,27 @@ static int coroutine_fn
> raw_co_zone_mgmt(BlockDriverState *bs, BlockZoneOp op,
> len >> BDRV_SECTOR_BITS);
> ret = raw_thread_pool_submit(bs, handle_aiocb_zone_mgmt, &acb);
> if (ret != 0) {
> + update_zones_wp(s->fd, wps, offset, i);
> ret = -errno;
> error_report("ioctl %s failed %d", op_name, ret);
> + goto out;
> + }
> +
> + if (zo == BLKRESETZONE && len == capacity) {
> + ret = get_zones_wp(s->fd, wps, 0, bs->bl.nr_zones, 1);
> + if (ret < 0) {
> + error_report("reporting single wp failed");
> + return ret;
> + }
> + } else if (zo == BLKRESETZONE) {
> + *wp = offset;
> + } else if (zo == BLKFINISHZONE) {
> + /* The zoned device allows the last zone smaller that the zone size.
> */
> + *wp = offset + len;
> }
The BLKRESETZONE and BLKFINISHZONE only update one zone's wp, but
[offset, offset+len) can cover multiple zones.
A loop is needed to update wps for multiple zones:
} else if (zo == BLKRESETZONE) {
for each zone {
wp[i] = offset + i * zone_size;
}
} else if (zo == BLKFINISHZONE) {
for each zone {
/* The last zone may be short */
wp[i] = MIN(offset + (i + 1) * zone_size, offset + len);
}
}
>
> +out:
> + qemu_co_mutex_unlock(&wps->colock);
> return ret;
> }
> #endif
> diff --git a/include/block/block-common.h b/include/block/block-common.h
> index 1576fcf2ed..93196229ac 100644
> --- a/include/block/block-common.h
> +++ b/include/block/block-common.h
> @@ -118,6 +118,14 @@ typedef struct BlockZoneDescriptor {
> BlockZoneState state;
> } BlockZoneDescriptor;
>
> +/*
> + * Track write pointers of a zone in bytes.
> + */
> +typedef struct BlockZoneWps {
> + CoMutex colock;
> + uint64_t wp[];
> +} BlockZoneWps;
> +
> typedef struct BlockDriverInfo {
> /* in bytes, 0 if irrelevant */
> int cluster_size;
> @@ -240,6 +248,12 @@ 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_CONV(wp) (wp & (1ULL << 63))
> +
> #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 1bd2aef4d5..69d1c3e6dd 100644
> --- a/include/block/block_int-common.h
> +++ b/include/block/block_int-common.h
> @@ -884,6 +884,11 @@ typedef struct BlockLimits {
>
> /* maximum number of active zones */
> int64_t max_active_zones;
> +
> + /* array of write pointers' location of each zone in the zoned device. */
> + BlockZoneWps *wps;
> +
> + int64_t write_granularity;
What is this limit? Is it specific to zones?
> } BlockLimits;
>
> typedef struct BdrvOpBlocker BdrvOpBlocker;
> --
> 2.39.2
>
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