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https://gitlab.com/qemu-project/qemu
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block: Require auto-read-only for existing fallbacks
Some block drivers have traditionally changed their node to read-only mode without asking the user. This behaviour has been marked deprecated since 2.11, expecting users to provide an explicit read-only=on option. Now that we have auto-read-only=on, enable these drivers to make use of the option. This is the only use of bdrv_set_read_only(), so we can make it a bit more specific and turn it into a bdrv_apply_auto_read_only() that is more convenient for drivers to use. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com>
This commit is contained in:
parent
a51b9c4862
commit
eaa2410f1e
40
block.c
40
block.c
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@ -266,29 +266,41 @@ int bdrv_can_set_read_only(BlockDriverState *bs, bool read_only,
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return 0;
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}
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/* TODO Remove (deprecated since 2.11)
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* Block drivers are not supposed to automatically change bs->read_only.
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* Instead, they should just check whether they can provide what the user
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* explicitly requested and error out if read-write is requested, but they can
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* only provide read-only access. */
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int bdrv_set_read_only(BlockDriverState *bs, bool read_only, Error **errp)
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/*
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* Called by a driver that can only provide a read-only image.
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*
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* Returns 0 if the node is already read-only or it could switch the node to
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* read-only because BDRV_O_AUTO_RDONLY is set.
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*
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* Returns -EACCES if the node is read-write and BDRV_O_AUTO_RDONLY is not set
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* or bdrv_can_set_read_only() forbids making the node read-only. If @errmsg
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* is not NULL, it is used as the error message for the Error object.
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*/
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int bdrv_apply_auto_read_only(BlockDriverState *bs, const char *errmsg,
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Error **errp)
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{
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int ret = 0;
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ret = bdrv_can_set_read_only(bs, read_only, false, errp);
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if (!(bs->open_flags & BDRV_O_RDWR)) {
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return 0;
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}
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if (!(bs->open_flags & BDRV_O_AUTO_RDONLY)) {
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goto fail;
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}
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ret = bdrv_can_set_read_only(bs, true, false, NULL);
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if (ret < 0) {
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return ret;
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goto fail;
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}
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bs->read_only = read_only;
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if (read_only) {
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bs->read_only = true;
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bs->open_flags &= ~BDRV_O_RDWR;
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} else {
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bs->open_flags |= BDRV_O_RDWR;
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}
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return 0;
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fail:
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error_setg(errp, "%s", errmsg ?: "Image is read-only");
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return -EACCES;
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}
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void bdrv_get_full_backing_filename_from_filename(const char *backed,
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@ -105,23 +105,18 @@ static int bochs_open(BlockDriverState *bs, QDict *options, int flags,
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struct bochs_header bochs;
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int ret;
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/* No write support yet */
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ret = bdrv_apply_auto_read_only(bs, NULL, errp);
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if (ret < 0) {
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return ret;
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}
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bs->file = bdrv_open_child(NULL, options, "file", bs, &child_file,
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false, errp);
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if (!bs->file) {
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return -EINVAL;
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}
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if (!bdrv_is_read_only(bs)) {
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error_report("Opening bochs images without an explicit read-only=on "
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"option is deprecated. Future versions will refuse to "
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"open the image instead of automatically marking the "
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"image read-only.");
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ret = bdrv_set_read_only(bs, true, errp); /* no write support yet */
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if (ret < 0) {
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return ret;
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}
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}
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ret = bdrv_pread(bs->file, 0, &bochs, sizeof(bochs));
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if (ret < 0) {
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return ret;
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@ -67,23 +67,17 @@ static int cloop_open(BlockDriverState *bs, QDict *options, int flags,
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uint32_t offsets_size, max_compressed_block_size = 1, i;
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int ret;
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ret = bdrv_apply_auto_read_only(bs, NULL, errp);
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if (ret < 0) {
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return ret;
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}
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bs->file = bdrv_open_child(NULL, options, "file", bs, &child_file,
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false, errp);
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if (!bs->file) {
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return -EINVAL;
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}
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if (!bdrv_is_read_only(bs)) {
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error_report("Opening cloop images without an explicit read-only=on "
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"option is deprecated. Future versions will refuse to "
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"open the image instead of automatically marking the "
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"image read-only.");
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ret = bdrv_set_read_only(bs, true, errp);
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if (ret < 0) {
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return ret;
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}
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}
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/* read header */
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ret = bdrv_pread(bs->file, 128, &s->block_size, 4);
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if (ret < 0) {
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16
block/dmg.c
16
block/dmg.c
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@ -413,23 +413,17 @@ static int dmg_open(BlockDriverState *bs, QDict *options, int flags,
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int64_t offset;
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int ret;
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ret = bdrv_apply_auto_read_only(bs, NULL, errp);
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if (ret < 0) {
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return ret;
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}
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bs->file = bdrv_open_child(NULL, options, "file", bs, &child_file,
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false, errp);
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if (!bs->file) {
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return -EINVAL;
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}
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if (!bdrv_is_read_only(bs)) {
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error_report("Opening dmg images without an explicit read-only=on "
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"option is deprecated. Future versions will refuse to "
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"open the image instead of automatically marking the "
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"image read-only.");
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ret = bdrv_set_read_only(bs, true, errp);
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if (ret < 0) {
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return ret;
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}
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}
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block_module_load_one("dmg-bz2");
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s->n_chunks = 0;
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@ -780,19 +780,12 @@ static int qemu_rbd_open(BlockDriverState *bs, QDict *options, int flags,
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/* If we are using an rbd snapshot, we must be r/o, otherwise
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* leave as-is */
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if (s->snap != NULL) {
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if (!bdrv_is_read_only(bs)) {
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error_report("Opening rbd snapshots without an explicit "
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"read-only=on option is deprecated. Future versions "
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"will refuse to open the image instead of "
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"automatically marking the image read-only.");
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r = bdrv_set_read_only(bs, true, &local_err);
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r = bdrv_apply_auto_read_only(bs, "rbd snapshots are read-only", errp);
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if (r < 0) {
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rbd_close(s->image);
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error_propagate(errp, local_err);
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goto failed_open;
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}
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}
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}
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r = 0;
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goto out;
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@ -1262,15 +1262,9 @@ static int vvfat_open(BlockDriverState *bs, QDict *options, int flags,
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"Unable to set VVFAT to 'rw' when drive is read-only");
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goto fail;
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}
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} else if (!bdrv_is_read_only(bs)) {
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error_report("Opening non-rw vvfat images without an explicit "
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"read-only=on option is deprecated. Future versions "
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"will refuse to open the image instead of "
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"automatically marking the image read-only.");
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/* read only is the default for safety */
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ret = bdrv_set_read_only(bs, true, &local_err);
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} else {
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ret = bdrv_apply_auto_read_only(bs, NULL, errp);
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if (ret < 0) {
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error_propagate(errp, local_err);
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goto fail;
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}
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}
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@ -438,7 +438,8 @@ int bdrv_is_allocated_above(BlockDriverState *top, BlockDriverState *base,
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bool bdrv_is_read_only(BlockDriverState *bs);
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int bdrv_can_set_read_only(BlockDriverState *bs, bool read_only,
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bool ignore_allow_rdw, Error **errp);
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int bdrv_set_read_only(BlockDriverState *bs, bool read_only, Error **errp);
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int bdrv_apply_auto_read_only(BlockDriverState *bs, const char *errmsg,
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Error **errp);
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bool bdrv_is_writable(BlockDriverState *bs);
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bool bdrv_is_sg(BlockDriverState *bs);
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bool bdrv_is_inserted(BlockDriverState *bs);
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