On Tue, Mar 05, 2024 at 09:45:22AM +1100, NeilBrown wrote:
> Currently find_openstateowner_str looks are done both in
> nfsd4_process_open1() and alloc_init_open_stateowner() - the latter
> possibly being a surprise based on its name.
>
> It would be easier to follow, and more conformant to common patterns, if
> the lookup was all in the one place.
>
> So replace alloc_init_open_stateowner() with
> find_or_alloc_open_stateowner() and use the latter in
> nfsd4_process_open1() without any calls to find_openstateowner_str().
>
> This means all finds are find_openstateowner_str_locked() and
> find_openstateowner_str() is no longer needed. So discard
> find_openstateowner_str() and rename find_openstateowner_str_locked() to
> find_openstateowner_str().
>
> Signed-off-by: NeilBrown <neilb@xxxxxxx>
> ---
> fs/nfsd/nfs4state.c | 93 +++++++++++++++++++--------------------------
> 1 file changed, 40 insertions(+), 53 deletions(-)
>
> diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
> index b9b3a2601675..0c1058e8cc4b 100644
> --- a/fs/nfsd/nfs4state.c
> +++ b/fs/nfsd/nfs4state.c
> @@ -541,7 +541,7 @@ same_owner_str(struct nfs4_stateowner *sop, struct xdr_netobj *owner)
> }
>
> static struct nfs4_openowner *
> -find_openstateowner_str_locked(unsigned int hashval, struct nfsd4_open *open,
> +find_openstateowner_str(unsigned int hashval, struct nfsd4_open *open,
> struct nfs4_client *clp)
> {
> struct nfs4_stateowner *so;
> @@ -558,18 +558,6 @@ find_openstateowner_str_locked(unsigned int hashval, struct nfsd4_open *open,
> return NULL;
> }
>
> -static struct nfs4_openowner *
> -find_openstateowner_str(unsigned int hashval, struct nfsd4_open *open,
> - struct nfs4_client *clp)
> -{
> - struct nfs4_openowner *oo;
> -
> - spin_lock(&clp->cl_lock);
> - oo = find_openstateowner_str_locked(hashval, open, clp);
> - spin_unlock(&clp->cl_lock);
> - return oo;
> -}
> -
> static inline u32
> opaque_hashval(const void *ptr, int nbytes)
> {
> @@ -4855,34 +4843,46 @@ nfsd4_find_and_lock_existing_open(struct nfs4_file *fp, struct nfsd4_open *open)
> }
>
> static struct nfs4_openowner *
> -alloc_init_open_stateowner(unsigned int strhashval, struct nfsd4_open *open,
> - struct nfsd4_compound_state *cstate)
> +find_or_alloc_open_stateowner(unsigned int strhashval, struct nfsd4_open *open,
> + struct nfsd4_compound_state *cstate)
> {
> struct nfs4_client *clp = cstate->clp;
> - struct nfs4_openowner *oo, *ret;
> + struct nfs4_openowner *oo, *new = NULL;
>
> - oo = alloc_stateowner(openowner_slab, &open->op_owner, clp);
> - if (!oo)
> - return NULL;
> - oo->oo_owner.so_ops = &openowner_ops;
> - oo->oo_owner.so_is_open_owner = 1;
> - oo->oo_owner.so_seqid = open->op_seqid;
> - oo->oo_flags = 0;
> - if (nfsd4_has_session(cstate))
> - oo->oo_flags |= NFS4_OO_CONFIRMED;
> - oo->oo_time = 0;
> - oo->oo_last_closed_stid = NULL;
> - INIT_LIST_HEAD(&oo->oo_close_lru);
> - spin_lock(&clp->cl_lock);
> - ret = find_openstateowner_str_locked(strhashval, open, clp);
> - if (ret == NULL) {
> - hash_openowner(oo, clp, strhashval);
> - ret = oo;
> - } else
> - nfs4_free_stateowner(&oo->oo_owner);
> + while (1) {
> + spin_lock(&clp->cl_lock);
> + oo = find_openstateowner_str(strhashval, open, clp);
> + if (oo && !(oo->oo_flags & NFS4_OO_CONFIRMED)) {
> + /* Replace unconfirmed owners without checking for replay. */
> + release_openowner(oo);
> + oo = NULL;
> + }
> + if (oo) {
> + spin_unlock(&clp->cl_lock);
> + if (new)
> + nfs4_free_stateowner(&new->oo_owner);
> + return oo;
> + }
> + if (new) {
> + hash_openowner(new, clp, strhashval);
> + spin_unlock(&clp->cl_lock);
> + return new;
> + }
> + spin_unlock(&clp->cl_lock);
>
> - spin_unlock(&clp->cl_lock);
> - return ret;
> + new = alloc_stateowner(openowner_slab, &open->op_owner, clp);
> + if (!new)
> + return NULL;
> + new->oo_owner.so_ops = &openowner_ops;
> + new->oo_owner.so_is_open_owner = 1;
> + new->oo_owner.so_seqid = open->op_seqid;
> + new->oo_flags = 0;
> + if (nfsd4_has_session(cstate))
> + new->oo_flags |= NFS4_OO_CONFIRMED;
> + new->oo_time = 0;
> + new->oo_last_closed_stid = NULL;
> + INIT_LIST_HEAD(&new->oo_close_lru);
> + }
> }
>
> static struct nfs4_ol_stateid *
> @@ -5331,28 +5331,15 @@ nfsd4_process_open1(struct nfsd4_compound_state *cstate,
> clp = cstate->clp;
>
> strhashval = ownerstr_hashval(&open->op_owner);
> - oo = find_openstateowner_str(strhashval, open, clp);
> + oo = find_or_alloc_open_stateowner(strhashval, open, cstate);
> open->op_openowner = oo;
> if (!oo)
> - goto new_owner;
> - if (!(oo->oo_flags & NFS4_OO_CONFIRMED)) {
> - /* Replace unconfirmed owners without checking for replay. */
> - release_openowner(oo);
> - open->op_openowner = NULL;
> - goto new_owner;
> - }
> + return nfserr_jukebox;
> nfsd4_cstate_assign_replay(cstate, &oo->oo_owner);
> status = nfsd4_check_seqid(cstate, &oo->oo_owner, open->op_seqid);
> if (status)
> return status;
> - goto alloc_stateid;
> -new_owner:
> - oo = alloc_init_open_stateowner(strhashval, open, cstate);
> - if (oo == NULL)
> - return nfserr_jukebox;
> - open->op_openowner = oo;
> - nfsd4_cstate_assign_replay(cstate, &oo->oo_owner);
> -alloc_stateid:
> +
> open->op_stp = nfs4_alloc_open_stateid(clp);
> if (!open->op_stp)
> return nfserr_jukebox;
> --
> 2.43.0
>
While running the NFSv4.0 pynfs tests with KASAN and lock debugging
enabled, I get a number of CPU soft lockup warnings on the test
server and then it wedges hard. I bisected to this patch.
Because we are just a day shy of the v6.9 merge window, I'm going to
drop these four patches for v6.9. We can try them again for v6.10.
--
Chuck Lever
