From a68f794bfd76b6ee5f517908233ce5fe8edcf9dc Mon Sep 17 00:00:00 2001 From: Kevin Wolf Date: Mon, 18 Jan 2021 13:34:47 +0100 Subject: [PATCH] block: Separate blk_is_writable() and blk_supports_write_perm() MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit Git-commit: 86b1cf322789b79c8ace977430ac6a443d491cc0 Currently, blk_is_read_only() tells whether a given BlockBackend can only be used in read-only mode because its root node is read-only. Some callers actually try to answer a slightly different question: Is the BlockBackend configured to be writable, by taking write permissions on the root node? This can differ, for example, for CD-ROM devices which don't take write permissions, but may be backed by a writable image file. scsi-cd allows write requests to the drive if blk_is_read_only() returns false. However, the write request will immediately run into an assertion failure because the write permission is missing. This patch introduces separate functions for both questions. blk_supports_write_perm() answers the question whether the block node/image file can support writable devices, whereas blk_is_writable() tells whether the BlockBackend is currently configured to be writable. All calls of blk_is_read_only() are converted to one of the two new functions. Fixes: https://bugs.launchpad.net/bugs/1906693 Cc: qemu-stable@nongnu.org Signed-off-by: Kevin Wolf Message-Id: <20210118123448.307825-2-kwolf@redhat.com> Reviewed-by: Philippe Mathieu-Daudé Reviewed-by: Max Reitz Signed-off-by: Kevin Wolf Signed-off-by: Bruce Rogers --- block/block-backend.c | 19 ++++++++++++++++--- hw/block/dataplane/xen-block.c | 2 +- hw/block/fdc.c | 9 +++++---- hw/block/m25p80.c | 6 +++--- hw/block/nand.c | 2 +- hw/block/nvme-ns.c | 7 ++++--- hw/block/onenand.c | 2 +- hw/block/pflash_cfi01.c | 2 +- hw/block/pflash_cfi02.c | 2 +- hw/block/swim.c | 6 +++--- hw/block/virtio-blk.c | 6 +++--- hw/block/xen-block.c | 2 +- hw/ide/core.c | 2 +- hw/misc/sifive_u_otp.c | 2 +- hw/ppc/pnv_pnor.c | 2 +- hw/scsi/scsi-disk.c | 10 +++++----- hw/scsi/scsi-generic.c | 4 ++-- hw/sd/sd.c | 6 +++--- hw/usb/dev-storage.c | 4 ++-- include/sysemu/block-backend.h | 3 ++- 20 files changed, 57 insertions(+), 41 deletions(-) diff --git a/block/block-backend.c b/block/block-backend.c index ce78d30..e493f17 100644 --- a/block/block-backend.c +++ b/block/block-backend.c @@ -1826,17 +1826,30 @@ void blk_error_action(BlockBackend *blk, BlockErrorAction action, } } -bool blk_is_read_only(BlockBackend *blk) +/* + * Returns true if the BlockBackend can support taking write permissions + * (because its root node is not read-only). + */ +bool blk_supports_write_perm(BlockBackend *blk) { BlockDriverState *bs = blk_bs(blk); if (bs) { - return bdrv_is_read_only(bs); + return !bdrv_is_read_only(bs); } else { - return blk->root_state.read_only; + return !blk->root_state.read_only; } } +/* + * Returns true if the BlockBackend can be written to in its current + * configuration (i.e. if write permission have been requested) + */ +bool blk_is_writable(BlockBackend *blk) +{ + return blk->perm & BLK_PERM_WRITE; +} + bool blk_is_sg(BlockBackend *blk) { BlockDriverState *bs = blk_bs(blk); diff --git a/hw/block/dataplane/xen-block.c b/hw/block/dataplane/xen-block.c index 71c337c..f5b4f4c 100644 --- a/hw/block/dataplane/xen-block.c +++ b/hw/block/dataplane/xen-block.c @@ -168,7 +168,7 @@ static int xen_block_parse_request(XenBlockRequest *request) }; if (request->req.operation != BLKIF_OP_READ && - blk_is_read_only(dataplane->blk)) { + !blk_is_writable(dataplane->blk)) { error_report("error: write req for ro device"); goto err; } diff --git a/hw/block/fdc.c b/hw/block/fdc.c index 4c2c35e..d6ba6c8 100644 --- a/hw/block/fdc.c +++ b/hw/block/fdc.c @@ -443,7 +443,7 @@ static void fd_revalidate(FDrive *drv) FLOPPY_DPRINTF("revalidate\n"); if (drv->blk != NULL) { - drv->ro = blk_is_read_only(drv->blk); + drv->ro = !blk_is_writable(drv->blk); if (!blk_is_inserted(drv->blk)) { FLOPPY_DPRINTF("No disk in drive\n"); drv->disk = FLOPPY_DRIVE_TYPE_NONE; @@ -478,8 +478,8 @@ static void fd_change_cb(void *opaque, bool load, Error **errp) blk_set_perm(drive->blk, 0, BLK_PERM_ALL, &error_abort); } else { if (!blkconf_apply_backend_options(drive->conf, - blk_is_read_only(drive->blk), false, - errp)) { + !blk_supports_write_perm(drive->blk), + false, errp)) { return; } } @@ -552,7 +552,8 @@ static void floppy_drive_realize(DeviceState *qdev, Error **errp) * read-only node later */ read_only = true; } else { - read_only = !blk_bs(dev->conf.blk) || blk_is_read_only(dev->conf.blk); + read_only = !blk_bs(dev->conf.blk) || + !blk_supports_write_perm(dev->conf.blk); } if (!blkconf_blocksizes(&dev->conf, errp)) { diff --git a/hw/block/m25p80.c b/hw/block/m25p80.c index 483925f..efe490a 100644 --- a/hw/block/m25p80.c +++ b/hw/block/m25p80.c @@ -499,7 +499,7 @@ static void flash_sync_page(Flash *s, int page) { QEMUIOVector *iov; - if (!s->blk || blk_is_read_only(s->blk)) { + if (!s->blk || !blk_is_writable(s->blk)) { return; } @@ -515,7 +515,7 @@ static inline void flash_sync_area(Flash *s, int64_t off, int64_t len) { QEMUIOVector *iov; - if (!s->blk || blk_is_read_only(s->blk)) { + if (!s->blk || !blk_is_writable(s->blk)) { return; } @@ -1278,7 +1278,7 @@ static void m25p80_realize(SSISlave *ss, Error **errp) if (s->blk) { uint64_t perm = BLK_PERM_CONSISTENT_READ | - (blk_is_read_only(s->blk) ? 0 : BLK_PERM_WRITE); + (blk_supports_write_perm(s->blk) ? BLK_PERM_WRITE : 0); ret = blk_set_perm(s->blk, perm, BLK_PERM_ALL, errp); if (ret < 0) { return; diff --git a/hw/block/nand.c b/hw/block/nand.c index 1d7a48a..8c5087f 100644 --- a/hw/block/nand.c +++ b/hw/block/nand.c @@ -409,7 +409,7 @@ static void nand_realize(DeviceState *dev, Error **errp) pagesize = 1 << s->oob_shift; s->mem_oob = 1; if (s->blk) { - if (blk_is_read_only(s->blk)) { + if (!blk_supports_write_perm(s->blk)) { error_setg(errp, "Can't use a read-only drive"); return; } diff --git a/hw/block/nvme-ns.c b/hw/block/nvme-ns.c index 31c80cd..2670787 100644 --- a/hw/block/nvme-ns.c +++ b/hw/block/nvme-ns.c @@ -48,13 +48,14 @@ static void nvme_ns_init(NvmeNamespace *ns) static int nvme_ns_init_blk(NvmeCtrl *n, NvmeNamespace *ns, Error **errp) { + bool read_only; + if (!blkconf_blocksizes(&ns->blkconf, errp)) { return -1; } - if (!blkconf_apply_backend_options(&ns->blkconf, - blk_is_read_only(ns->blkconf.blk), - false, errp)) { + read_only = !blk_supports_write_perm(ns->blkconf.blk); + if (!blkconf_apply_backend_options(&ns->blkconf, read_only, false, errp)) { return -1; } diff --git a/hw/block/onenand.c b/hw/block/onenand.c index 5ff7be8..08994ca 100644 --- a/hw/block/onenand.c +++ b/hw/block/onenand.c @@ -796,7 +796,7 @@ static void onenand_realize(DeviceState *dev, Error **errp) s->image = memset(g_malloc(size + (size >> 5)), 0xff, size + (size >> 5)); } else { - if (blk_is_read_only(s->blk)) { + if (!blk_supports_write_perm(s->blk)) { error_setg(errp, "Can't use a read-only drive"); return; } diff --git a/hw/block/pflash_cfi01.c b/hw/block/pflash_cfi01.c index daae965..af0bb6c 100644 --- a/hw/block/pflash_cfi01.c +++ b/hw/block/pflash_cfi01.c @@ -744,7 +744,7 @@ static void pflash_cfi01_realize(DeviceState *dev, Error **errp) if (pfl->blk) { uint64_t perm; - pfl->ro = blk_is_read_only(pfl->blk); + pfl->ro = !blk_supports_write_perm(pfl->blk); perm = BLK_PERM_CONSISTENT_READ | (pfl->ro ? 0 : BLK_PERM_WRITE); ret = blk_set_perm(pfl->blk, perm, BLK_PERM_ALL, errp); if (ret < 0) { diff --git a/hw/block/pflash_cfi02.c b/hw/block/pflash_cfi02.c index 1b3d94e..1a855c5 100644 --- a/hw/block/pflash_cfi02.c +++ b/hw/block/pflash_cfi02.c @@ -801,7 +801,7 @@ static void pflash_cfi02_realize(DeviceState *dev, Error **errp) if (pfl->blk) { uint64_t perm; - pfl->ro = blk_is_read_only(pfl->blk); + pfl->ro = !blk_supports_write_perm(pfl->blk); perm = BLK_PERM_CONSISTENT_READ | (pfl->ro ? 0 : BLK_PERM_WRITE); ret = blk_set_perm(pfl->blk, perm, BLK_PERM_ALL, errp); if (ret < 0) { diff --git a/hw/block/swim.c b/hw/block/swim.c index 20133a8..509c2f4 100644 --- a/hw/block/swim.c +++ b/hw/block/swim.c @@ -137,8 +137,8 @@ static void swim_change_cb(void *opaque, bool load, Error **errp) blk_set_perm(drive->blk, 0, BLK_PERM_ALL, &error_abort); } else { if (!blkconf_apply_backend_options(drive->conf, - blk_is_read_only(drive->blk), false, - errp)) { + !blk_supports_write_perm(drive->blk), + false, errp)) { return; } } @@ -210,7 +210,7 @@ static void swim_drive_realize(DeviceState *qdev, Error **errp) dev->conf.werror = BLOCKDEV_ON_ERROR_AUTO; if (!blkconf_apply_backend_options(&dev->conf, - blk_is_read_only(dev->conf.blk), + !blk_supports_write_perm(dev->conf.blk), false, errp)) { return; } diff --git a/hw/block/virtio-blk.c b/hw/block/virtio-blk.c index bac2d6f..e8600b0 100644 --- a/hw/block/virtio-blk.c +++ b/hw/block/virtio-blk.c @@ -1021,7 +1021,7 @@ static uint64_t virtio_blk_get_features(VirtIODevice *vdev, uint64_t features, virtio_has_feature(features, VIRTIO_BLK_F_CONFIG_WCE))) { virtio_add_feature(&features, VIRTIO_BLK_F_WCE); } - if (blk_is_read_only(s->blk)) { + if (!blk_is_writable(s->blk)) { virtio_add_feature(&features, VIRTIO_BLK_F_RO); } if (s->conf.num_queues > 1) { @@ -1175,8 +1175,8 @@ static void virtio_blk_device_realize(DeviceState *dev, Error **errp) } if (!blkconf_apply_backend_options(&conf->conf, - blk_is_read_only(conf->conf.blk), true, - errp)) { + !blk_supports_write_perm(conf->conf.blk), + true, errp)) { return; } s->original_wce = blk_enable_write_cache(conf->conf.blk); diff --git a/hw/block/xen-block.c b/hw/block/xen-block.c index 8a7a3f5..20b23c6 100644 --- a/hw/block/xen-block.c +++ b/hw/block/xen-block.c @@ -574,7 +574,7 @@ static void xen_disk_realize(XenBlockDevice *blockdev, Error **errp) return; } - blockdev->info = blk_is_read_only(conf->blk) ? VDISK_READONLY : 0; + blockdev->info = blk_supports_write_perm(conf->blk) ? 0 : VDISK_READONLY; } static void xen_disk_class_init(ObjectClass *class, void *data) diff --git a/hw/ide/core.c b/hw/ide/core.c index e858216..50758a9 100644 --- a/hw/ide/core.c +++ b/hw/ide/core.c @@ -2537,7 +2537,7 @@ int ide_init_drive(IDEState *s, BlockBackend *blk, IDEDriveKind kind, error_setg(errp, "Device needs media, but drive is empty"); return -1; } - if (blk_is_read_only(blk)) { + if (!blk_is_writable(blk)) { error_setg(errp, "Can't use a read-only drive"); return -1; } diff --git a/hw/misc/sifive_u_otp.c b/hw/misc/sifive_u_otp.c index 6006637..84547eb 100644 --- a/hw/misc/sifive_u_otp.c +++ b/hw/misc/sifive_u_otp.c @@ -218,7 +218,7 @@ static void sifive_u_otp_realize(DeviceState *dev, Error **errp) if (s->blk) { perm = BLK_PERM_CONSISTENT_READ | - (blk_is_read_only(s->blk) ? 0 : BLK_PERM_WRITE); + (blk_supports_write_perm(s->blk) ? BLK_PERM_WRITE : 0); ret = blk_set_perm(s->blk, perm, BLK_PERM_ALL, errp); if (ret < 0) { return; diff --git a/hw/ppc/pnv_pnor.c b/hw/ppc/pnv_pnor.c index c365ee5..cc2a6a3 100644 --- a/hw/ppc/pnv_pnor.c +++ b/hw/ppc/pnv_pnor.c @@ -85,7 +85,7 @@ static void pnv_pnor_realize(DeviceState *dev, Error **errp) if (s->blk) { uint64_t perm = BLK_PERM_CONSISTENT_READ | - (blk_is_read_only(s->blk) ? 0 : BLK_PERM_WRITE); + (blk_supports_write_perm(s->blk) ? BLK_PERM_WRITE : 0); ret = blk_set_perm(s->blk, perm, BLK_PERM_ALL, errp); if (ret < 0) { return; diff --git a/hw/scsi/scsi-disk.c b/hw/scsi/scsi-disk.c index 90841ad..7ab2be0 100644 --- a/hw/scsi/scsi-disk.c +++ b/hw/scsi/scsi-disk.c @@ -1269,7 +1269,7 @@ static int scsi_disk_emulate_mode_sense(SCSIDiskReq *r, uint8_t *outbuf) if (s->qdev.type == TYPE_DISK) { dev_specific_param = s->features & (1 << SCSI_DISK_F_DPOFUA) ? 0x10 : 0; - if (blk_is_read_only(s->qdev.conf.blk)) { + if (!blk_is_writable(s->qdev.conf.blk)) { dev_specific_param |= 0x80; /* Readonly. */ } } else { @@ -1703,7 +1703,7 @@ static void scsi_disk_emulate_unmap(SCSIDiskReq *r, uint8_t *inbuf) goto invalid_param_len; } - if (blk_is_read_only(s->qdev.conf.blk)) { + if (!blk_is_writable(s->qdev.conf.blk)) { block_acct_invalid(blk_get_stats(s->qdev.conf.blk), BLOCK_ACCT_UNMAP); scsi_check_condition(r, SENSE_CODE(WRITE_PROTECTED)); return; @@ -1794,7 +1794,7 @@ static void scsi_disk_emulate_write_same(SCSIDiskReq *r, uint8_t *inbuf) return; } - if (blk_is_read_only(s->qdev.conf.blk)) { + if (!blk_is_writable(s->qdev.conf.blk)) { scsi_check_condition(r, SENSE_CODE(WRITE_PROTECTED)); return; } @@ -2206,7 +2206,7 @@ static int32_t scsi_disk_dma_command(SCSIRequest *req, uint8_t *buf) case WRITE_VERIFY_10: case WRITE_VERIFY_12: case WRITE_VERIFY_16: - if (blk_is_read_only(s->qdev.conf.blk)) { + if (!blk_is_writable(s->qdev.conf.blk)) { scsi_check_condition(r, SENSE_CODE(WRITE_PROTECTED)); return 0; } @@ -2379,7 +2379,7 @@ static void scsi_realize(SCSIDevice *dev, Error **errp) } } - read_only = blk_is_read_only(s->qdev.conf.blk); + read_only = !blk_supports_write_perm(s->qdev.conf.blk); if (dev->type == TYPE_ROM) { read_only = true; } diff --git a/hw/scsi/scsi-generic.c b/hw/scsi/scsi-generic.c index 2cb23ca..836479a 100644 --- a/hw/scsi/scsi-generic.c +++ b/hw/scsi/scsi-generic.c @@ -305,7 +305,7 @@ static void scsi_read_complete(void * opaque, int ret) * readonly. */ if ((s->type == TYPE_DISK || s->type == TYPE_TAPE || s->type == TYPE_ZBC) && - blk_is_read_only(s->conf.blk) && + !blk_is_writable(s->conf.blk) && (r->req.cmd.buf[0] == MODE_SENSE || r->req.cmd.buf[0] == MODE_SENSE_10) && (r->req.cmd.buf[1] & 0x8) == 0) { @@ -693,7 +693,7 @@ static void scsi_generic_realize(SCSIDevice *s, Error **errp) return; } if (!blkconf_apply_backend_options(&s->conf, - blk_is_read_only(s->conf.blk), + !blk_supports_write_perm(s->conf.blk), true, errp)) { return; } diff --git a/hw/sd/sd.c b/hw/sd/sd.c index 1842c03..5cdcd54 100644 --- a/hw/sd/sd.c +++ b/hw/sd/sd.c @@ -583,7 +583,7 @@ static void sd_reset(DeviceState *dev) sd_set_sdstatus(sd); g_free(sd->wp_groups); - sd->wp_switch = sd->blk ? blk_is_read_only(sd->blk) : false; + sd->wp_switch = sd->blk ? !blk_is_writable(sd->blk) : false; sd->wpgrps_size = sect; sd->wp_groups = bitmap_new(sd->wpgrps_size); memset(sd->function_group, 0, sizeof(sd->function_group)); @@ -751,7 +751,7 @@ void sd_set_cb(SDState *sd, qemu_irq readonly, qemu_irq insert) { sd->readonly_cb = readonly; sd->inserted_cb = insert; - qemu_set_irq(readonly, sd->blk ? blk_is_read_only(sd->blk) : 0); + qemu_set_irq(readonly, sd->blk ? !blk_is_writable(sd->blk) : 0); qemu_set_irq(insert, sd->blk ? blk_is_inserted(sd->blk) : 0); } @@ -2155,7 +2155,7 @@ static void sd_realize(DeviceState *dev, Error **errp) if (sd->blk) { int64_t blk_size; - if (blk_is_read_only(sd->blk)) { + if (!blk_supports_write_perm(sd->blk)) { error_setg(errp, "Cannot use read-only drive as SD card"); return; } diff --git a/hw/usb/dev-storage.c b/hw/usb/dev-storage.c index f0f0058..c49e8b8 100644 --- a/hw/usb/dev-storage.c +++ b/hw/usb/dev-storage.c @@ -613,8 +613,8 @@ static void usb_msd_storage_realize(USBDevice *dev, Error **errp) return; } - if (!blkconf_apply_backend_options(&s->conf, blk_is_read_only(blk), true, - errp)) { + if (!blkconf_apply_backend_options(&s->conf, !blk_supports_write_perm(blk), + true, errp)) { return; } diff --git a/include/sysemu/block-backend.h b/include/sysemu/block-backend.h index 8203d7f..880e903 100644 --- a/include/sysemu/block-backend.h +++ b/include/sysemu/block-backend.h @@ -191,7 +191,8 @@ BlockErrorAction blk_get_error_action(BlockBackend *blk, bool is_read, int error); void blk_error_action(BlockBackend *blk, BlockErrorAction action, bool is_read, int error); -bool blk_is_read_only(BlockBackend *blk); +bool blk_supports_write_perm(BlockBackend *blk); +bool blk_is_writable(BlockBackend *blk); bool blk_is_sg(BlockBackend *blk); bool blk_enable_write_cache(BlockBackend *blk); void blk_set_enable_write_cache(BlockBackend *blk, bool wce); -- 2.7.4