Commit 64107dc0 authored by Kevin Wolf's avatar Kevin Wolf
Browse files

file-posix: Support auto-read-only option 



If read-only=off, but auto-read-only=on is given, open the file
read-write if we have the permissions, but instead of erroring out for
read-only files, just degrade to read-only.

Signed-off-by: default avatarKevin Wolf <kwolf@redhat.com>
Reviewed-by: default avatarEric Blake <eblake@redhat.com>
parent 6c2e581d

block/file-posix.c

+16 −3
Original line number Diff line number Diff line
@@ -527,9 +527,22 @@ static int raw_open_common(BlockDriverState *bs, QDict *options, 


    s->fd = -1;

    fd = qemu_open(filename, s->open_flags, 0644);

    if (fd < 0) {

        ret = -errno;

        error_setg_errno(errp, errno, "Could not open '%s'", filename);

    ret = fd < 0 ? -errno : 0;



    if (ret == -EACCES || ret == -EROFS) {

        /* Try to degrade to read-only, but if it doesn't work, still use the

         * normal error message. */

        if (bdrv_apply_auto_read_only(bs, NULL, NULL) == 0) {

            bdrv_flags &= ~BDRV_O_RDWR;

            raw_parse_flags(bdrv_flags, &s->open_flags);

            assert(!(s->open_flags & O_CREAT));

            fd = qemu_open(filename, s->open_flags);

            ret = fd < 0 ? -errno : 0;

        }

    }



    if (ret < 0) {

        error_setg_errno(errp, -ret, "Could not open '%s'", filename);

        if (ret == -EROFS) {

            ret = -EACCES;

        }