On Fri, 16 Feb 2024, trondmy@xxxxxxxxxx wrote:
> From: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx>
>
> Commit bb4d53d66e4b broke the NFSv3 pre/post op attributes behaviour
> when doing a SETATTR rpc call by stripping out the calls to
> fh_fill_pre_attrs() and fh_fill_post_attrs().
>
> Fixes: bb4d53d66e4b ("NFSD: use (un)lock_inode instead of fh_(un)lock for file operations")
> Signed-off-by: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx>
> ---
> fs/nfsd/nfs4proc.c | 4 ++++
> fs/nfsd/vfs.c | 9 +++++++--
> 2 files changed, 11 insertions(+), 2 deletions(-)
>
> diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c
> index 14712fa08f76..e6d8624efc83 100644
> --- a/fs/nfsd/nfs4proc.c
> +++ b/fs/nfsd/nfs4proc.c
> @@ -1143,6 +1143,7 @@ nfsd4_setattr(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
> };
> struct inode *inode;
> __be32 status = nfs_ok;
> + bool save_no_wcc;
> int err;
>
> if (setattr->sa_iattr.ia_valid & ATTR_SIZE) {
> @@ -1168,8 +1169,11 @@ nfsd4_setattr(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
>
> if (status)
> goto out;
> + save_no_wcc = cstate->current_fh.fh_no_wcc;
> + cstate->current_fh.fh_no_wcc = true;
> status = nfsd_setattr(rqstp, &cstate->current_fh, &attrs,
> 0, (time64_t)0);
> + cstate->current_fh.fh_no_wcc = save_no_wcc;
This looks clumsy.
I think the background is that NFSv3 needs atomic wcc attributes for
file operations, but NFSv4 doesn't - it only has them for directory ops.
So NFSv4, like NFSv2, doesn't want fh_fill_pre_attrs() to be called by
nfsd_setattr().
NFSv2 avoids it by always setting ->fh_no_wcc. Here you temporarily set
fh_no_wcc to true for the same effect. So the code is correct.
But it is not obvious to the casual reader why this is happening.
I would rather a "wcc_wanted" flag or similar, but that can be done in a
separate clean-up patch later.
Thanks for finding and fixing this regression of mine.
Reviewed-by: NeilBrown <neilb@xxxxxxx>
NeilBrown
> if (!status)
> status = nfserrno(attrs.na_labelerr);
> if (!status)
> diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c
> index 6e7e37192461..58fab461bc00 100644
> --- a/fs/nfsd/vfs.c
> +++ b/fs/nfsd/vfs.c
> @@ -497,7 +497,7 @@ nfsd_setattr(struct svc_rqst *rqstp, struct svc_fh *fhp,
> int accmode = NFSD_MAY_SATTR;
> umode_t ftype = 0;
> __be32 err;
> - int host_err;
> + int host_err = 0;
> bool get_write_count;
> bool size_change = (iap->ia_valid & ATTR_SIZE);
> int retries;
> @@ -555,6 +555,9 @@ nfsd_setattr(struct svc_rqst *rqstp, struct svc_fh *fhp,
> }
>
> inode_lock(inode);
> + err = fh_fill_pre_attrs(fhp);
> + if (err)
> + goto out_unlock;
> for (retries = 1;;) {
> struct iattr attrs;
>
> @@ -582,13 +585,15 @@ nfsd_setattr(struct svc_rqst *rqstp, struct svc_fh *fhp,
> attr->na_aclerr = set_posix_acl(&nop_mnt_idmap,
> dentry, ACL_TYPE_DEFAULT,
> attr->na_dpacl);
> + fh_fill_post_attrs(fhp);
> +out_unlock:
> inode_unlock(inode);
> if (size_change)
> put_write_access(inode);
> out:
> if (!host_err)
> host_err = commit_metadata(fhp);
> - return nfserrno(host_err);
> + return err != 0 ? err : nfserrno(host_err);
> }
>
> #if defined(CONFIG_NFSD_V4)
> --
> 2.43.1
>
>
>
