Re: [PATCH] fs/nfsd: Fix creation time serialization order

From: Jeff Layton
Date: Tue Jun 27 2023 - 12:09:39 EST


On Fri, 2023-06-23 at 17:09 -0400, tavianator@xxxxxxxxxxxxxx wrote:
> From: Tavian Barnes <tavianator@xxxxxxxxxxxxxx>
>
> In nfsd4_encode_fattr(), TIME_CREATE was being written out after all
> other times. However, they should be written out in an order that
> matches the bit flags in bmval1, which in this case are
>
> #define FATTR4_WORD1_TIME_ACCESS (1UL << 15)
> #define FATTR4_WORD1_TIME_CREATE (1UL << 18)
> #define FATTR4_WORD1_TIME_DELTA (1UL << 19)
> #define FATTR4_WORD1_TIME_METADATA (1UL << 20)
> #define FATTR4_WORD1_TIME_MODIFY (1UL << 21)
>
> so TIME_CREATE should come second.
>
> I noticed this on a FreeBSD NFSv4.2 client, which supports creation
> times. On this client, file times were weirdly permuted. With this
> patch applied on the server, times looked normal on the client.
>
> Fixes: e377a3e698fb ("nfsd: Add support for the birth time attribute")
> Link: https://unix.stackexchange.com/q/749605/56202
> Signed-off-by: Tavian Barnes <tavianator@xxxxxxxxxxxxxx>
> ---
> fs/nfsd/nfs4xdr.c | 14 +++++++-------
> 1 file changed, 7 insertions(+), 7 deletions(-)
>
> diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
> index 76db2fe29624..3037c5b0623e 100644
> --- a/fs/nfsd/nfs4xdr.c
> +++ b/fs/nfsd/nfs4xdr.c
> @@ -3354,6 +3354,13 @@ nfsd4_encode_fattr(struct xdr_stream *xdr, struct svc_fh *fhp,
> p = xdr_encode_hyper(p, (s64)stat.atime.tv_sec);
> *p++ = cpu_to_be32(stat.atime.tv_nsec);
> }
> + if (bmval1 & FATTR4_WORD1_TIME_CREATE) {
> + p = xdr_reserve_space(xdr, 12);
> + if (!p)
> + goto out_resource;
> + p = xdr_encode_hyper(p, (s64)stat.btime.tv_sec);
> + *p++ = cpu_to_be32(stat.btime.tv_nsec);
> + }
> if (bmval1 & FATTR4_WORD1_TIME_DELTA) {
> p = xdr_reserve_space(xdr, 12);
> if (!p)
> @@ -3374,13 +3381,6 @@ nfsd4_encode_fattr(struct xdr_stream *xdr, struct svc_fh *fhp,
> p = xdr_encode_hyper(p, (s64)stat.mtime.tv_sec);
> *p++ = cpu_to_be32(stat.mtime.tv_nsec);
> }
> - if (bmval1 & FATTR4_WORD1_TIME_CREATE) {
> - p = xdr_reserve_space(xdr, 12);
> - if (!p)
> - goto out_resource;
> - p = xdr_encode_hyper(p, (s64)stat.btime.tv_sec);
> - *p++ = cpu_to_be32(stat.btime.tv_nsec);
> - }
> if (bmval1 & FATTR4_WORD1_MOUNTED_ON_FILEID) {
> u64 ino = stat.ino;
>

Reviewed-by: Jeff Layton <jlayton@xxxxxxxxxx>