On 1/20/2011 12:59 AM, Stefan Hajnoczi wrote:
> On Tue, Jan 18, 2011 at 01:54:16PM +0530, M. Mohan Kumar wrote:
>> After creating a file object, its permission and ownership details are
>> updated
>> as per client's request for both passthrough and none security model. But
>> with
>> chrooted environment its not required for passthrough security model. Move
>> all
>> post file creation changes to none security model
>>
>> Signed-off-by: M. Mohan Kumar <mo...@in.ibm.com>
>> ---
>> hw/9pfs/virtio-9p-local.c | 19 ++++++-------------
>> 1 files changed, 6 insertions(+), 13 deletions(-)
>>
>> diff --git a/hw/9pfs/virtio-9p-local.c b/hw/9pfs/virtio-9p-local.c
>> index 08fd67f..d2e32e2 100644
>> --- a/hw/9pfs/virtio-9p-local.c
>> +++ b/hw/9pfs/virtio-9p-local.c
>> @@ -208,21 +208,14 @@ static int local_set_xattr(const char *path, FsCred
>> *credp)
>> return 0;
>> }
>>
>> -static int local_post_create_passthrough(FsContext *fs_ctx, const char
>> *path,
>> +static int local_post_create_none(FsContext *fs_ctx, const char *path,
>> FsCred *credp)
>> {
>> + int retval;
>> if (chmod(rpath(fs_ctx, path), credp->fc_mode & 07777) < 0) {
>> return -1;
>> }
>> - if (lchown(rpath(fs_ctx, path), credp->fc_uid, credp->fc_gid) < 0) {
>> - /*
>> - * If we fail to change ownership and if we are
>> - * using security model none. Ignore the error
>> - */
>> - if (fs_ctx->fs_sm != SM_NONE) {
>> - return -1;
>> - }
>> - }
>> + retval = lchown(rpath(fs_ctx, path), credp->fc_uid, credp->fc_gid);
>> return 0;
>> }
>
> retval is unused.
>
> Can multiple virtio-9p requests execute at a time? chmod() and lchown()
> after creation is a race condition if other requests can execute
> concurrently.
If some level of serialization is needed it will be done at the client/guest
inode level.
Are you worried about filesystem semantics? or do you see some corruption if
they
get executed in parallel?
JV
>
> Stefan
>
