From de29d97cab7b97d776cbb1077079eff0bfc46186 Mon Sep 17 00:00:00 2001 From: Kevin Wolf Date: Tue, 29 Nov 2011 12:42:20 +0100 Subject: [PATCH 10/37] raw: Probe required direct I/O alignment Message-id: <1392117622-28812-11-git-send-email-kwolf@redhat.com> Patchwork-id: 57175 O-Subject: [RHEL-7.0 qemu-kvm PATCH v2 10/37] raw: Probe required direct I/O alignment Bugzilla: 748906 RH-Acked-by: Laszlo Ersek RH-Acked-by: Stefan Hajnoczi RH-Acked-by: Max Reitz From: Paolo Bonzini 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 Signed-off-by: Kevin Wolf Reviewed-by: Max Reitz (cherry picked from commit c25f53b06eba1575d5d0e92a0132455c97825b83) Signed-off-by: Kevin Wolf --- 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(-) --- 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 f2102bc..40a4a34 100644 --- a/block.c +++ b/block.c @@ -780,6 +780,7 @@ 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); @@ -845,6 +846,8 @@ 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 f410668..9ee5b8e 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); @@ -464,7 +536,6 @@ static int raw_reopen_prepare(BDRVReopenState *state, return ret; } - static void raw_reopen_commit(BDRVReopenState *state) { BDRVRawReopenState *raw_s = state->opaque; @@ -500,23 +571,15 @@ 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, @@ -1739,6 +1803,7 @@ 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, @@ -1869,6 +1934,7 @@ 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, @@ -1978,6 +2044,7 @@ 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, @@ -2105,6 +2172,7 @@ 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 6ac3797..ac20370 100644 --- a/block/raw-win32.c +++ b/block/raw-win32.c @@ -201,6 +201,35 @@ 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); @@ -268,6 +297,17 @@ 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]); + } + 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 0445e6b..e66bd5f 100644 --- a/include/block/block_int.h +++ b/include/block/block_int.h @@ -307,6 +307,9 @@ 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; -- 1.7.1