From: Eric Blake Date: Tue, 3 May 2016 22:39:06 +0000 (-0600) Subject: block: Make supported_write_flags a per-bds property X-Git-Tag: v2.7.0-rc0~189^2~6 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=4df863f336b76faf55f796eed7cd7f7c55ec0130;p=thirdparty%2Fqemu.git block: Make supported_write_flags a per-bds property Pre-patch, .supported_write_flags lives at the driver level, which means we are blindly declaring that all block devices using a given driver will either equally support FUA, or that we need a fallback at the block layer. But there are drivers where FUA support is a per-block decision: the NBD block driver is dependent on the remote server advertising NBD_FLAG_SEND_FUA (and has fallback code to duplicate the flush that the block layer would do if NBD had not set .supported_write_flags); and the iscsi block driver is dependent on the mode sense bits advertised by the underlying device (and is currently silently ignoring FUA requests if the underlying device does not support FUA). The fix is to make supported flags as a per-BDS option, set during .bdrv_open(). This patch moves the variable and fixes NBD and iscsi to set it only conditionally; later patches will then further simplify the NBD driver to quit duplicating work done at the block layer, as well as tackle the fact that SCSI does not support FUA semantics on WRITESAME(10/16) but only on WRITE(10/16). Signed-off-by: Eric Blake Reviewed-by: Fam Zheng Acked-by: Stefan Hajnoczi Signed-off-by: Kevin Wolf --- diff --git a/block/io.c b/block/io.c index 0db1146159b..1fb7afeaf0c 100644 --- a/block/io.c +++ b/block/io.c @@ -841,9 +841,10 @@ static int coroutine_fn bdrv_driver_pwritev(BlockDriverState *bs, if (drv->bdrv_co_writev_flags) { ret = drv->bdrv_co_writev_flags(bs, sector_num, nb_sectors, qiov, - flags); + flags & bs->supported_write_flags); + flags &= ~bs->supported_write_flags; } else if (drv->bdrv_co_writev) { - assert(drv->supported_write_flags == 0); + assert(!bs->supported_write_flags); ret = drv->bdrv_co_writev(bs, sector_num, nb_sectors, qiov); } else { BlockAIOCB *acb; @@ -862,9 +863,7 @@ static int coroutine_fn bdrv_driver_pwritev(BlockDriverState *bs, } emulate_flags: - if (ret == 0 && (flags & BDRV_REQ_FUA) && - !(drv->supported_write_flags & BDRV_REQ_FUA)) - { + if (ret == 0 && (flags & BDRV_REQ_FUA)) { ret = bdrv_co_flush(bs); } diff --git a/block/iscsi.c b/block/iscsi.c index 4f7520463e4..6d5c1f6cebb 100644 --- a/block/iscsi.c +++ b/block/iscsi.c @@ -456,8 +456,11 @@ iscsi_co_writev_flags(BlockDriverState *bs, int64_t sector_num, int nb_sectors, struct IscsiTask iTask; uint64_t lba; uint32_t num_sectors; - bool fua; + bool fua = flags & BDRV_REQ_FUA; + if (fua) { + assert(iscsilun->dpofua); + } if (!is_request_lun_aligned(sector_num, nb_sectors, iscsilun)) { return -EINVAL; } @@ -472,7 +475,6 @@ iscsi_co_writev_flags(BlockDriverState *bs, int64_t sector_num, int nb_sectors, num_sectors = sector_qemu2lun(nb_sectors, iscsilun); iscsi_co_init_iscsitask(iscsilun, &iTask); retry: - fua = iscsilun->dpofua && (flags & BDRV_REQ_FUA); if (iscsilun->use_16_for_rw) { iTask.task = iscsi_write16_task(iscsilun->iscsi, iscsilun->lun, lba, NULL, num_sectors * iscsilun->block_size, @@ -1548,6 +1550,9 @@ static int iscsi_open(BlockDriverState *bs, QDict *options, int flags, task = NULL; iscsi_modesense_sync(iscsilun); + if (iscsilun->dpofua) { + bs->supported_write_flags = BDRV_REQ_FUA; + } /* Check the write protect flag of the LUN if we want to write */ if (iscsilun->type == TYPE_DISK && (flags & BDRV_O_RDWR) && @@ -1841,7 +1846,6 @@ static BlockDriver bdrv_iscsi = { .bdrv_co_write_zeroes = iscsi_co_write_zeroes, .bdrv_co_readv = iscsi_co_readv, .bdrv_co_writev_flags = iscsi_co_writev_flags, - .supported_write_flags = BDRV_REQ_FUA, .bdrv_co_flush_to_disk = iscsi_co_flush, #ifdef __linux__ diff --git a/block/nbd-client.c b/block/nbd-client.c index 878e879ace7..5fc96e98565 100644 --- a/block/nbd-client.c +++ b/block/nbd-client.c @@ -414,6 +414,9 @@ int nbd_client_init(BlockDriverState *bs, logout("Failed to negotiate with the NBD server\n"); return ret; } + if (client->nbdflags & NBD_FLAG_SEND_FUA) { + bs->supported_write_flags = BDRV_REQ_FUA; + } qemu_co_mutex_init(&client->send_mutex); qemu_co_mutex_init(&client->free_sema); diff --git a/block/nbd.c b/block/nbd.c index fccbfef5851..a4fba911c36 100644 --- a/block/nbd.c +++ b/block/nbd.c @@ -471,7 +471,6 @@ static BlockDriver bdrv_nbd = { .bdrv_file_open = nbd_open, .bdrv_co_readv = nbd_co_readv, .bdrv_co_writev_flags = nbd_co_writev_flags, - .supported_write_flags = BDRV_REQ_FUA, .bdrv_close = nbd_close, .bdrv_co_flush_to_os = nbd_co_flush, .bdrv_co_discard = nbd_co_discard, @@ -490,7 +489,6 @@ static BlockDriver bdrv_nbd_tcp = { .bdrv_file_open = nbd_open, .bdrv_co_readv = nbd_co_readv, .bdrv_co_writev_flags = nbd_co_writev_flags, - .supported_write_flags = BDRV_REQ_FUA, .bdrv_close = nbd_close, .bdrv_co_flush_to_os = nbd_co_flush, .bdrv_co_discard = nbd_co_discard, @@ -509,7 +507,6 @@ static BlockDriver bdrv_nbd_unix = { .bdrv_file_open = nbd_open, .bdrv_co_readv = nbd_co_readv, .bdrv_co_writev_flags = nbd_co_writev_flags, - .supported_write_flags = BDRV_REQ_FUA, .bdrv_close = nbd_close, .bdrv_co_flush_to_os = nbd_co_flush, .bdrv_co_discard = nbd_co_discard, diff --git a/block/raw_bsd.c b/block/raw_bsd.c index 5e65fb02d48..1a1618ef073 100644 --- a/block/raw_bsd.c +++ b/block/raw_bsd.c @@ -204,6 +204,7 @@ static int raw_open(BlockDriverState *bs, QDict *options, int flags, Error **errp) { bs->sg = bs->file->bs->sg; + bs->supported_write_flags = BDRV_REQ_FUA; if (bs->probed && !bdrv_is_read_only(bs)) { fprintf(stderr, @@ -250,7 +251,6 @@ BlockDriver bdrv_raw = { .bdrv_create = &raw_create, .bdrv_co_readv = &raw_co_readv, .bdrv_co_writev_flags = &raw_co_writev_flags, - .supported_write_flags = BDRV_REQ_FUA, .bdrv_co_write_zeroes = &raw_co_write_zeroes, .bdrv_co_discard = &raw_co_discard, .bdrv_co_get_block_status = &raw_co_get_block_status, diff --git a/include/block/block_int.h b/include/block/block_int.h index 6fbe6482314..10f4962fe8b 100644 --- a/include/block/block_int.h +++ b/include/block/block_int.h @@ -158,8 +158,6 @@ struct BlockDriver { int coroutine_fn (*bdrv_co_pwritev)(BlockDriverState *bs, uint64_t offset, uint64_t bytes, QEMUIOVector *qiov, int flags); - int supported_write_flags; - /* * Efficiently zero a region of the disk image. Typically an image format * would use a compact metadata representation to implement this. This @@ -445,6 +443,8 @@ struct BlockDriverState { /* Alignment requirement for offset/length of I/O requests */ unsigned int request_alignment; + /* Flags honored during pwrite (so far: BDRV_REQ_FUA) */ + unsigned int supported_write_flags; /* the following member gives a name to every node on the bs graph. */ char node_name[32];