block: return EPERM on writes or discards to read-only devices

This is the behavior in the operating system, for example Linux's
blkdev_write_iter has the following:

        if (bdev_read_only(I_BDEV(bd_inode)))
                return -EPERM;

This does not apply to opening a device for read/write, when the
device only supports read-only operation.  In this case any of
EACCES, EPERM or EROFS is acceptable depending on why writing is
not possible.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-id: 1431013548-22492-1-git-send-email-pbonzini@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
This commit is contained in:
Paolo Bonzini 2015-05-07 17:45:48 +02:00 committed by Stefan Hajnoczi
parent fd0e60530f
commit eaf5fe2dd4

View File

@ -1205,7 +1205,7 @@ static int coroutine_fn bdrv_co_do_pwritev(BlockDriverState *bs,
return -ENOMEDIUM; return -ENOMEDIUM;
} }
if (bs->read_only) { if (bs->read_only) {
return -EACCES; return -EPERM;
} }
ret = bdrv_check_byte_request(bs, offset, bytes); ret = bdrv_check_byte_request(bs, offset, bytes);
@ -2340,7 +2340,7 @@ int coroutine_fn bdrv_co_discard(BlockDriverState *bs, int64_t sector_num,
if (ret < 0) { if (ret < 0) {
return ret; return ret;
} else if (bs->read_only) { } else if (bs->read_only) {
return -EROFS; return -EPERM;
} }
bdrv_reset_dirty(bs, sector_num, nb_sectors); bdrv_reset_dirty(bs, sector_num, nb_sectors);