From e2b8247a322cd92945785edf25f09e6b3e8285f9 Mon Sep 17 00:00:00 2001 From: Jeff Cody Date: Fri, 7 Apr 2017 16:55:26 -0400 Subject: block: do not set BDS read_only if copy_on_read enabled A few block drivers will set the BDS read_only flag from their .bdrv_open() function. This means the bs->read_only flag could be set after we enable copy_on_read, as the BDRV_O_COPY_ON_READ flag check occurs prior to the call to bdrv->bdrv_open(). This adds an error return to bdrv_set_read_only(), and an error will be return if we try to set the BDS to read_only while copy_on_read is enabled. This patch also changes the behavior of vvfat. Before, vvfat could override the drive 'readonly' flag with its own, internal 'rw' flag. For instance, this -drive parameter would result in a writable image: "-drive format=vvfat,dir=/tmp/vvfat,rw,if=virtio,readonly=on" This is not correct. Now, attempting to use the above -drive parameter will result in an error (i.e., 'rw' is incompatible with 'readonly=on'). Signed-off-by: Jeff Cody Reviewed-by: Stefan Hajnoczi Reviewed-by: John Snow Message-id: 0c5b4c1cc2c651471b131f21376dfd5ea24d2196.1491597120.git.jcody@redhat.com --- block.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) (limited to 'block.c') diff --git a/block.c b/block.c index 6f21145..67ae35a 100644 --- a/block.c +++ b/block.c @@ -192,9 +192,17 @@ void path_combine(char *dest, int dest_size, } } -void bdrv_set_read_only(BlockDriverState *bs, bool read_only) +int bdrv_set_read_only(BlockDriverState *bs, bool read_only, Error **errp) { + /* Do not set read_only if copy_on_read is enabled */ + if (bs->copy_on_read && read_only) { + error_setg(errp, "Can't set node '%s' to r/o with copy-on-read enabled", + bdrv_get_device_or_node_name(bs)); + return -EINVAL; + } + bs->read_only = read_only; + return 0; } void bdrv_get_full_backing_filename_from_filename(const char *backed, -- cgit v1.1