Le Friday 17 Jan 2014 à 15:14:58 (+0100), Kevin Wolf a écrit :
> From: Paolo Bonzini <pbonz...@redhat.com>
>
> Add a bs->request_alignment field that contains the required
> offset/length alignment for I/O requests and fill it in the raw block
> drivers. Use ioctls if possible, else see what alignment it takes for
> O_DIRECT to succeed.
>
> While at it, also expose the memory alignment requirements, which may be
> (and in practice are) different from the disk alignment requirements.
>
> Signed-off-by: Paolo Bonzini <pbonz...@redhat.com>
> Signed-off-by: Kevin Wolf <kw...@redhat.com>
> Reviewed-by: Max Reitz <mre...@redhat.com>
> ---
> block.c | 3 ++
> block/raw-posix.c | 102
> ++++++++++++++++++++++++++++++++++++++--------
> block/raw-win32.c | 41 +++++++++++++++++++
> include/block/block_int.h | 3 ++
> 4 files changed, 132 insertions(+), 17 deletions(-)
>
> diff --git a/block.c b/block.c
> index b738abe..25ae896 100644
> --- a/block.c
> +++ b/block.c
> @@ -813,6 +813,7 @@ static int bdrv_open_common(BlockDriverState *bs,
> BlockDriverState *file,
>
> bs->open_flags = flags;
> bs->guest_block_size = 512;
> + bs->request_alignment = 512;
> bs->zero_beyond_eof = true;
> open_flags = bdrv_open_flags(bs, flags);
> bs->read_only = !(open_flags & BDRV_O_RDWR);
> @@ -881,6 +882,8 @@ static int bdrv_open_common(BlockDriverState *bs,
> BlockDriverState *file,
> }
>
> bdrv_refresh_limits(bs);
> + assert(bdrv_opt_mem_align(bs) != 0);
> + assert(bs->request_alignment != 0);
>
> #ifndef _WIN32
> if (bs->is_temporary) {
> diff --git a/block/raw-posix.c b/block/raw-posix.c
> index 0676037..126a634 100644
> --- a/block/raw-posix.c
> +++ b/block/raw-posix.c
> @@ -127,6 +127,8 @@ typedef struct BDRVRawState {
> int fd;
> int type;
> int open_flags;
> + size_t buf_align;
> +
> #if defined(__linux__)
> /* linux floppy specific */
> int64_t fd_open_time;
> @@ -213,6 +215,76 @@ static int raw_normalize_devicepath(const char
> **filename)
> }
> #endif
>
> +static void raw_probe_alignment(BlockDriverState *bs)
> +{
> + BDRVRawState *s = bs->opaque;
> + char *buf;
> + unsigned int sector_size;
> +
> + /* For /dev/sg devices the alignment is not really used.
> + With buffered I/O, we don't have any restrictions. */
> + if (bs->sg || !(s->open_flags & O_DIRECT)) {
> + bs->request_alignment = 1;
> + s->buf_align = 1;
> + return;
> + }
> +
> + /* Try a few ioctls to get the right size */
> + bs->request_alignment = 0;
> + s->buf_align = 0;
> +
> +#ifdef BLKSSZGET
> + if (ioctl(s->fd, BLKSSZGET, §or_size) >= 0) {
> + bs->request_alignment = sector_size;
> + }
> +#endif
> +#ifdef DKIOCGETBLOCKSIZE
> + if (ioctl(s->fd, DKIOCGETBLOCKSIZE, §or_size) >= 0) {
> + bs->request_alignment = sector_size;
> + }
> +#endif
> +#ifdef DIOCGSECTORSIZE
> + if (ioctl(s->fd, DIOCGSECTORSIZE, §or_size) >= 0) {
> + bs->request_alignment = sector_size;
> + }
> +#endif
> +#ifdef CONFIG_XFS
> + if (s->is_xfs) {
> + struct dioattr da;
> + if (xfsctl(NULL, s->fd, XFS_IOC_DIOINFO, &da) >= 0) {
> + bs->request_alignment = da.d_miniosz;
> + /* The kernel returns wrong information for d_mem */
> + /* s->buf_align = da.d_mem; */
> + }
> + }
> +#endif
> +
> + /* If we could not get the sizes so far, we can only guess them */
> + if (!s->buf_align) {
> + size_t align;
> + buf = qemu_memalign(MAX_BLOCKSIZE, 2 * MAX_BLOCKSIZE);
> + for (align = 512; align <= MAX_BLOCKSIZE; align <<= 1) {
> + if (pread(s->fd, buf + align, MAX_BLOCKSIZE, 0) >= 0) {
> + s->buf_align = align;
> + break;
> + }
> + }
> + qemu_vfree(buf);
> + }
> +
> + if (!bs->request_alignment) {
> + size_t align;
> + buf = qemu_memalign(s->buf_align, MAX_BLOCKSIZE);
> + for (align = 512; align <= MAX_BLOCKSIZE; align <<= 1) {
> + if (pread(s->fd, buf, align, 0) >= 0) {
> + bs->request_alignment = align;
> + break;
> + }
> + }
> + qemu_vfree(buf);
> + }
> +}
> +
> static void raw_parse_flags(int bdrv_flags, int *open_flags)
> {
> assert(open_flags != NULL);
> @@ -463,7 +535,6 @@ static int raw_reopen_prepare(BDRVReopenState *state,
> return ret;
> }
>
> -
> static void raw_reopen_commit(BDRVReopenState *state)
> {
> BDRVRawReopenState *raw_s = state->opaque;
> @@ -499,23 +570,15 @@ static void raw_reopen_abort(BDRVReopenState *state)
> state->opaque = NULL;
> }
>
> +static int raw_refresh_limits(BlockDriverState *bs)
> +{
> + BDRVRawState *s = bs->opaque;
>
> -/* XXX: use host sector size if necessary with:
> -#ifdef DIOCGSECTORSIZE
> - {
> - unsigned int sectorsize = 512;
> - if (!ioctl(fd, DIOCGSECTORSIZE, §orsize) &&
> - sectorsize > bufsize)
> - bufsize = sectorsize;
> - }
> -#endif
> -#ifdef CONFIG_COCOA
> - uint32_t blockSize = 512;
> - if ( !ioctl( fd, DKIOCGETBLOCKSIZE, &blockSize ) && blockSize >
> bufsize) {
> - bufsize = blockSize;
> - }
> -#endif
> -*/
> + raw_probe_alignment(bs);
> + bs->bl.opt_mem_alignment = s->buf_align;
> +
> + return 0;
> +}
>
> static ssize_t handle_aiocb_ioctl(RawPosixAIOData *aiocb)
> {
> @@ -1363,6 +1426,7 @@ static BlockDriver bdrv_file = {
> .bdrv_aio_writev = raw_aio_writev,
> .bdrv_aio_flush = raw_aio_flush,
> .bdrv_aio_discard = raw_aio_discard,
> + .bdrv_refresh_limits = raw_refresh_limits,
>
> .bdrv_truncate = raw_truncate,
> .bdrv_getlength = raw_getlength,
> @@ -1740,6 +1804,7 @@ static BlockDriver bdrv_host_device = {
> .bdrv_aio_writev = raw_aio_writev,
> .bdrv_aio_flush = raw_aio_flush,
> .bdrv_aio_discard = hdev_aio_discard,
> + .bdrv_refresh_limits = raw_refresh_limits,
>
> .bdrv_truncate = raw_truncate,
> .bdrv_getlength = raw_getlength,
> @@ -1871,6 +1936,7 @@ static BlockDriver bdrv_host_floppy = {
> .bdrv_aio_readv = raw_aio_readv,
> .bdrv_aio_writev = raw_aio_writev,
> .bdrv_aio_flush = raw_aio_flush,
> + .bdrv_refresh_limits = raw_refresh_limits,
>
> .bdrv_truncate = raw_truncate,
> .bdrv_getlength = raw_getlength,
> @@ -1981,6 +2047,7 @@ static BlockDriver bdrv_host_cdrom = {
> .bdrv_aio_readv = raw_aio_readv,
> .bdrv_aio_writev = raw_aio_writev,
> .bdrv_aio_flush = raw_aio_flush,
> + .bdrv_refresh_limits = raw_refresh_limits,
>
> .bdrv_truncate = raw_truncate,
> .bdrv_getlength = raw_getlength,
> @@ -2110,6 +2177,7 @@ static BlockDriver bdrv_host_cdrom = {
> .bdrv_aio_readv = raw_aio_readv,
> .bdrv_aio_writev = raw_aio_writev,
> .bdrv_aio_flush = raw_aio_flush,
> + .bdrv_refresh_limits = raw_refresh_limits,
>
> .bdrv_truncate = raw_truncate,
> .bdrv_getlength = raw_getlength,
> diff --git a/block/raw-win32.c b/block/raw-win32.c
> index ce314fd..beb7f23 100644
> --- a/block/raw-win32.c
> +++ b/block/raw-win32.c
> @@ -202,6 +202,35 @@ static int set_sparse(int fd)
> NULL, 0, NULL, 0, &returned, NULL);
> }
>
> +static void raw_probe_alignment(BlockDriverState *bs)
> +{
> + BDRVRawState *s = bs->opaque;
> + DWORD sectorsPerCluster, freeClusters, totalClusters, count;
> + DISK_GEOMETRY_EX dg;
> + BOOL status;
> +
> + if (s->type == FTYPE_CD) {
> + bs->request_alignment = 2048;
> + return;
> + }
> + if (s->type == FTYPE_HARDDISK) {
> + status = DeviceIoControl(s->hfile, IOCTL_DISK_GET_DRIVE_GEOMETRY_EX,
> + NULL, 0, &dg, sizeof(dg), &count, NULL);
> + if (status != 0) {
> + bs->request_alignment = dg.Geometry.BytesPerSector;
> + return;
> + }
> + /* try GetDiskFreeSpace too */
> + }
> +
> + if (s->drive_path[0]) {
> + GetDiskFreeSpace(s->drive_path, §orsPerCluster,
> + &dg.Geometry.BytesPerSector,
> + &freeClusters, &totalClusters);
> + bs->request_alignment = dg.Geometry.BytesPerSector;
> + }
> +}
> +
> static void raw_parse_flags(int flags, int *access_flags, DWORD *overlapped)
> {
> assert(access_flags != NULL);
> @@ -269,6 +298,17 @@ static int raw_open(BlockDriverState *bs, QDict
> *options, int flags,
> }
> }
>
> + if (filename[0] && filename[1] == ':') {
> + snprintf(s->drive_path, sizeof(s->drive_path), "%c:\\", filename[0]);
> + } else if (filename[0] == '\\' && filename[1] == '\\') {
> + s->drive_path[0] = 0;
> + } else {
> + /* Relative path. */
> + char buf[MAX_PATH];
> + GetCurrentDirectory(MAX_PATH, buf);
> + snprintf(s->drive_path, sizeof(s->drive_path), "%c:\\", buf[0]);
> + }
> +
This is not really alignment related.
Does this really belong to this patch ?
Best regards
Benoît
> s->hfile = CreateFile(filename, access_flags,
> FILE_SHARE_READ, NULL,
> OPEN_EXISTING, overlapped, NULL);
> @@ -293,6 +333,7 @@ static int raw_open(BlockDriverState *bs, QDict *options,
> int flags,
> s->aio = aio;
> }
>
> + raw_probe_alignment(bs);
> ret = 0;
> fail:
> qemu_opts_del(opts);
> diff --git a/include/block/block_int.h b/include/block/block_int.h
> index 36c068f..fb1d355 100644
> --- a/include/block/block_int.h
> +++ b/include/block/block_int.h
> @@ -319,6 +319,9 @@ struct BlockDriverState {
> /* Whether produces zeros when read beyond eof */
> bool zero_beyond_eof;
>
> + /* Alignment requirement for offset/length of I/O requests */
> + unsigned int request_alignment;
> +
> /* the block size for which the guest device expects atomicity */
> int guest_block_size;
>
> --
> 1.8.1.4
>
>
