From patchwork Wed Jun 26 18:46:24 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Zhijian Li (Fujitsu)\" via" X-Patchwork-Id: 11018467 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 3B6241575 for ; Wed, 26 Jun 2019 20:55:14 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 2BFC61FF29 for ; Wed, 26 Jun 2019 20:55:14 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 2063C283C9; Wed, 26 Jun 2019 20:55:14 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.0 required=2.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,MAILING_LIST_MULTI,RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 8CBA11FF29 for ; Wed, 26 Jun 2019 20:55:13 +0000 (UTC) Received: from localhost ([::1]:44862 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hgEwi-0005jv-Ke for patchwork-qemu-devel@patchwork.kernel.org; Wed, 26 Jun 2019 16:55:12 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:44896) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hgEsM-0003rk-UB for qemu-devel@nongnu.org; Wed, 26 Jun 2019 16:50:44 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hgEsL-0005h7-HH for qemu-devel@nongnu.org; Wed, 26 Jun 2019 16:50:42 -0400 Received: from lizzy.crudebyte.com ([91.194.90.13]:47527) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hgEsL-0004mM-A7 for qemu-devel@nongnu.org; Wed, 26 Jun 2019 16:50:41 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=crudebyte.com; s=lizzy; h=Subject:Date:Cc:To:From:References:In-Reply-To: Message-Id:Sender:Reply-To:MIME-Version:Content-Type: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=m+LzS1451scdkEEys2FRbJmpMFaBVTxicT3+nDaCl+8=; b=av+Ku9UiNZSfirr4HZuBKi1mf 4bCUE0bQkkgjJSa2sdyJk2D8ZT2ZR6JRlJyFf6qAm6tBpcwi8NqN1wJKnqyKKvejDIrQJGlfkIG4+ 2f0Ia/F1J60XLNhuoz+L2kA2wmtbi9MZy5bQLH7cCm2fKfxBOsuX5PYeLFOyVbhkVFPXKJVMRlZ3y nC80BLdPMu8bfXJNDVkfvpqH1GvqzKhZgoe4NQRE73M3PY1lOY/bJrH7BhHnh2/SP8Ca61Y/p217S MvXMHu152AgpaWb3y87ZgA/VfkHHFFVBS3q1gOk9uK8xoTfqOuubjtNwNvS+TLcUpvOIhS60Y+ucP 4nmfHNvsg==; Message-Id: In-Reply-To: References: To: qemu-devel@nongnu.org Date: Wed, 26 Jun 2019 20:46:24 +0200 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 91.194.90.13 Subject: [Qemu-devel] [PATCH v4 4/5] 9p: stat_to_qid: implement slow path X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-Patchwork-Original-From: Christian Schoenebeck via Qemu-devel From: "Zhijian Li (Fujitsu)\" via" Reply-To: Christian Schoenebeck Cc: =?unknown-8bit?q?=22Daniel_P=2E_Berrang=C3=A9=22_=3Cberrange=40redhat=2E?= =?unknown-8bit?q?com=3E=2C_Greg_Kurz_=3Cgroug=40kaod=2Eorg=3E=2C_Antonios_M?= =?unknown-8bit?q?otakis_=3Cantonios=2Emotakis=40huawei=2Ecom=3E?= Errors-To: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: "Qemu-devel" X-Virus-Scanned: ClamAV using ClamSMTP stat_to_qid attempts via qid_path_prefixmap to map unique files (which are identified by 64 bit inode nr and 32 bit device id) to a 64 QID path value. However this implementation makes some assumptions about inode number generation on the host. If qid_path_prefixmap fails, we still have 48 bits available in the QID path to fall back to a less memory efficient full mapping. Signed-off-by: Antonios Motakis Signed-off-by: Christian Schoenebeck --- hw/9pfs/9p.c | 63 +++++++++++++++++++++++++++++++++++++++++++++++++++++++----- hw/9pfs/9p.h | 9 +++++++++ 2 files changed, 67 insertions(+), 5 deletions(-) diff --git a/hw/9pfs/9p.c b/hw/9pfs/9p.c index 7ccc68a829..e6e410972f 100644 --- a/hw/9pfs/9p.c +++ b/hw/9pfs/9p.c @@ -579,23 +579,69 @@ static uint32_t qpp_hash(QppEntry e) return qemu_xxhash7(e.ino_prefix, e.dev, 0, 0, 0); } +static uint32_t qpf_hash(QpfEntry e) +{ + return qemu_xxhash7(e.ino, e.dev, 0, 0, 0); +} + static bool qpp_lookup_func(const void *obj, const void *userp) { const QppEntry *e1 = obj, *e2 = userp; return e1->dev == e2->dev && e1->ino_prefix == e2->ino_prefix; } -static void qpp_table_remove(void *p, uint32_t h, void *up) +static bool qpf_lookup_func(const void *obj, const void *userp) +{ + const QpfEntry *e1 = obj, *e2 = userp; + return e1->dev == e2->dev && e1->ino == e2->ino; +} + +static void qp_table_remove(void *p, uint32_t h, void *up) { g_free(p); } -static void qpp_table_destroy(struct qht *ht) +static void qp_table_destroy(struct qht *ht) { - qht_iter(ht, qpp_table_remove, NULL); + qht_iter(ht, qp_table_remove, NULL); qht_destroy(ht); } +static int qid_path_fullmap(V9fsPDU *pdu, const struct stat *stbuf, + uint64_t *path) +{ + QpfEntry lookup = { + .dev = stbuf->st_dev, + .ino = stbuf->st_ino + }, *val; + uint32_t hash = qpf_hash(lookup); + + /* most users won't need the fullmap, so init the table lazily */ + if (!pdu->s->qpf_table.map) { + qht_init(&pdu->s->qpf_table, qpf_lookup_func, 1 << 16, QHT_MODE_AUTO_RESIZE); + } + + val = qht_lookup(&pdu->s->qpf_table, &lookup, hash); + + if (!val) { + if (pdu->s->qp_fullpath_next == 0) { + /* no more files can be mapped :'( */ + return -ENFILE; + } + + val = g_malloc0(sizeof(QppEntry)); + *val = lookup; + + /* new unique inode and device combo */ + val->path = pdu->s->qp_fullpath_next++; + pdu->s->qp_fullpath_next &= QPATH_INO_MASK; + qht_insert(&pdu->s->qpf_table, val, hash, NULL); + } + + *path = val->path; + return 0; +} + /* stat_to_qid needs to map inode number (64 bits) and device id (32 bits) * to a unique QID path (64 bits). To avoid having to map and keep track * of up to 2^64 objects, we map only the 16 highest bits of the inode plus @@ -642,6 +688,10 @@ static int stat_to_qid(V9fsPDU *pdu, const struct stat *stbuf, V9fsQID *qidp) if (pdu->s->ctx.export_flags & V9FS_REMAP_INODES) { /* map inode+device to qid path (fast path) */ err = qid_path_prefixmap(pdu, stbuf, &qidp->path); + if (err == -ENFILE) { + /* fast path didn't work, fall back to full map */ + err = qid_path_fullmap(pdu, stbuf, &qidp->path); + } if (err) { return err; } @@ -3752,6 +3802,7 @@ int v9fs_device_realize_common(V9fsState *s, const V9fsTransport *t, /* QID path hash table. 1 entry ought to be enough for anybody ;) */ qht_init(&s->qpp_table, qpp_lookup_func, 1, QHT_MODE_AUTO_RESIZE); s->qp_prefix_next = 1; /* reserve 0 to detect overflow */ + s->qp_fullpath_next = 1; s->ctx.fst = &fse->fst; fsdev_throttle_init(s->ctx.fst); @@ -3766,7 +3817,8 @@ out: } g_free(s->tag); g_free(s->ctx.fs_root); - qpp_table_destroy(&s->qpp_table); + qp_table_destroy(&s->qpp_table); + qp_table_destroy(&s->qpf_table); v9fs_path_free(&path); } return rc; @@ -3779,7 +3831,8 @@ void v9fs_device_unrealize_common(V9fsState *s, Error **errp) } fsdev_throttle_cleanup(s->ctx.fst); g_free(s->tag); - qpp_table_destroy(&s->qpp_table); + qp_table_destroy(&s->qpp_table); + qp_table_destroy(&s->qpf_table); g_free(s->ctx.fs_root); } diff --git a/hw/9pfs/9p.h b/hw/9pfs/9p.h index 0200e04176..2b74561030 100644 --- a/hw/9pfs/9p.h +++ b/hw/9pfs/9p.h @@ -245,6 +245,13 @@ typedef struct { uint16_t qp_prefix; } QppEntry; +/* QID path full entry, as above */ +typedef struct { + dev_t dev; + ino_t ino; + uint64_t path; +} QpfEntry; + struct V9fsState { QLIST_HEAD(, V9fsPDU) free_list; @@ -268,7 +275,9 @@ struct V9fsState V9fsQID root_qid; dev_t dev_id; struct qht qpp_table; + struct qht qpf_table; uint16_t qp_prefix_next; + uint64_t qp_fullpath_next; }; /* 9p2000.L open flags */