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 --- include/sysemu/block-backend.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'include/sysemu') diff --git a/include/sysemu/block-backend.h b/include/sysemu/block-backend.h index 8203d7f6f9..880e903293 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); -- cgit v1.2.3-55-g7522