nfsd4: use recall_lock for delegation hashing
This fixes a bug in the handling of the fi_delegations list. nfs4_setlease does not hold the recall_lock when adding to it. The client_mutex is held, which prevents against concurrent list changes, but nfsd_break_deleg_cb does not hold while walking it. New delegations could theoretically creep onto the list while we're walking it there. Signed-off-by: Benny Halevy <bhalevy@primarydata.com> Signed-off-by: Jeff Layton <jlayton@primarydata.com> Cc: stable@vger.kernel.org Signed-off-by: J. Bruce Fields <bfields@redhat.com>
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@ -433,12 +433,21 @@ static void unhash_stid(struct nfs4_stid *s)
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s->sc_type = 0;
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}
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static void
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hash_delegation_locked(struct nfs4_delegation *dp, struct nfs4_file *fp)
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{
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lockdep_assert_held(&recall_lock);
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list_add(&dp->dl_perfile, &fp->fi_delegations);
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list_add(&dp->dl_perclnt, &dp->dl_stid.sc_client->cl_delegations);
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}
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/* Called under the state lock. */
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static void
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unhash_delegation(struct nfs4_delegation *dp)
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{
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list_del_init(&dp->dl_perclnt);
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spin_lock(&recall_lock);
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list_del_init(&dp->dl_perclnt);
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list_del_init(&dp->dl_perfile);
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list_del_init(&dp->dl_recall_lru);
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spin_unlock(&recall_lock);
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@ -3065,11 +3074,12 @@ static int nfs4_setlease(struct nfs4_delegation *dp)
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status = vfs_setlease(fl->fl_file, fl->fl_type, &fl);
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if (status)
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goto out_free;
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list_add(&dp->dl_perclnt, &dp->dl_stid.sc_client->cl_delegations);
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fp->fi_lease = fl;
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fp->fi_deleg_file = get_file(fl->fl_file);
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atomic_set(&fp->fi_delegees, 1);
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list_add(&dp->dl_perfile, &fp->fi_delegations);
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spin_lock(&recall_lock);
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hash_delegation_locked(dp, fp);
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spin_unlock(&recall_lock);
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return 0;
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out_free:
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locks_free_lock(fl);
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@ -3090,9 +3100,8 @@ static int nfs4_set_delegation(struct nfs4_delegation *dp, struct nfs4_file *fp)
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spin_unlock(&recall_lock);
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return -EAGAIN;
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}
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list_add(&dp->dl_perfile, &fp->fi_delegations);
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hash_delegation_locked(dp, fp);
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spin_unlock(&recall_lock);
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list_add(&dp->dl_perclnt, &dp->dl_stid.sc_client->cl_delegations);
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return 0;
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}
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@ -4903,6 +4912,7 @@ static u64 nfsd_find_all_delegations(struct nfs4_client *clp, u64 max,
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struct nfs4_delegation *dp, *next;
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u64 count = 0;
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lockdep_assert_held(&recall_lock);
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list_for_each_entry_safe(dp, next, &clp->cl_delegations, dl_perclnt) {
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if (victims)
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list_move(&dp->dl_recall_lru, victims);
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