From 86b1cf322789b79c8ace977430ac6a443d491cc0 Mon Sep 17 00:00:00 2001 From: Kevin Wolf Date: Mon, 18 Jan 2021 13:34:47 +0100 Subject: block: Separate blk_is_writable() and blk_supports_write_perm() 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 --- hw/scsi/scsi-disk.c | 10 +++++----- hw/scsi/scsi-generic.c | 4 ++-- 2 files changed, 7 insertions(+), 7 deletions(-) (limited to 'hw/scsi') diff --git a/hw/scsi/scsi-disk.c b/hw/scsi/scsi-disk.c index 29504ea081..ed52fcd49f 100644 --- a/hw/scsi/scsi-disk.c +++ b/hw/scsi/scsi-disk.c @@ -1270,7 +1270,7 @@ 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 { @@ -1704,7 +1704,7 @@ 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; @@ -1795,7 +1795,7 @@ 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; } @@ -2207,7 +2207,7 @@ 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; } @@ -2380,7 +2380,7 @@ 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 9740f7e36a..ab220141f5 100644 --- a/hw/scsi/scsi-generic.c +++ b/hw/scsi/scsi-generic.c @@ -306,7 +306,7 @@ 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) { @@ -694,7 +694,7 @@ 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; } -- cgit v1.2.3-55-g7522