From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-11.6 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C5493C3A5A1 for ; Thu, 22 Aug 2019 21:59:25 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 6DE1921655 for ; Thu, 22 Aug 2019 21:59:25 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=crudebyte.com header.i=@crudebyte.com header.b="bMI2h6a6" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6DE1921655 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=nongnu.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:48134 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1i0v76-0006gc-Hy for qemu-devel@archiver.kernel.org; Thu, 22 Aug 2019 17:59:24 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:43056) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from <2f8ddf611be0b69ce936e4bd1bf3b18156a22995@lizzy.crudebyte.com>) id 1i0v5y-0005rP-7W for qemu-devel@nongnu.org; Thu, 22 Aug 2019 17:58:15 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from <2f8ddf611be0b69ce936e4bd1bf3b18156a22995@lizzy.crudebyte.com>) id 1i0v5w-0006ar-QY for qemu-devel@nongnu.org; Thu, 22 Aug 2019 17:58:14 -0400 Received: from lizzy.crudebyte.com ([91.194.90.13]:38799) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from <2f8ddf611be0b69ce936e4bd1bf3b18156a22995@lizzy.crudebyte.com>) id 1i0v5w-0006I3-K8 for qemu-devel@nongnu.org; Thu, 22 Aug 2019 17:58:12 -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=t+Ow+NmaIpgO7UyfrCCEQHSXZ9UqtAyOsPA67TZO4Rk=; b=bMI2h6a62H01nlUY0OxJkbeJt aP4CnMyDXelbnxpiBXcObWurXAVpLJVT5UTBa9/vpLIgeB32RyGFLI/UiP1cUj0cfX8C4skhZwAv5 MCS2gdHgiY4LhzJCVoXucctW92Z0gmi7kNtIuZbNLYWftw+TjZHCihvcaeBuUWPXQqJ8mn34wTbtM CjN8Th0Rc/18OvIqgViKm8tB6fjN5qSwwUO9V2BHP+kqyi5C90o3dfXtc5lvkQMuawUS9RnUaah6r ClcYyBmqA8JhAGan3hupRyrpmnCfg1QTcIcdX34aJHaO33CL5wGbrIqGMeqg7y3SGzrA1lZHPo2Iw 546ki2kzw==; Message-Id: <2f8ddf611be0b69ce936e4bd1bf3b18156a22995.1566503584.git.qemu_oss@crudebyte.com> In-Reply-To: References: To: qemu-devel@nongnu.org Date: Thu, 22 Aug 2019 21:44:28 +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 v6 3/4] 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: , From: Christian Schoenebeck via Qemu-devel Reply-To: Christian Schoenebeck Cc: Stefan Hajnoczi , Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= , Greg Kurz , Antonios Motakis , "Dr. David Alan Gilbert" Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" 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 [CS: - Rebased to https://github.com/gkurz/qemu/commits/9p-next (SHA1 177fd3b6a8). - Updated hash calls to new xxhash API. - Removed unnecessary parantheses in qpf_lookup_func(). - Removed unnecessary g_malloc0() result checks. - Log error message when running out of prefixes in qid_path_fullmap(). - Log error message about potential degraded performance in qid_path_prefixmap(). - Fixed typo in comment. ] Signed-off-by: Christian Schoenebeck --- hw/9pfs/9p.c | 70 ++++++++++++++++++++++++++++++++++++++++++++++++++++++------ hw/9pfs/9p.h | 9 ++++++++ 2 files changed, 72 insertions(+), 7 deletions(-) diff --git a/hw/9pfs/9p.c b/hw/9pfs/9p.c index c96ea51116..728641fb7f 100644 --- a/hw/9pfs/9p.c +++ b/hw/9pfs/9p.c @@ -579,23 +579,73 @@ 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 :'( */ + error_report_once( + "9p: No more prefixes available for remapping inodes from " + "host to guest." + ); + 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 @@ -621,8 +671,7 @@ static int qid_path_prefixmap(V9fsPDU *pdu, const struct stat *stbuf, if (pdu->s->qp_prefix_next == 0) { /* we ran out of prefixes */ error_report_once( - "9p: No more prefixes available for remapping inodes from " - "host to guest." + "9p: Potential degraded performance of inode remapping" ); return -ENFILE; } @@ -647,6 +696,10 @@ 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; } @@ -3813,6 +3866,7 @@ 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); @@ -3827,7 +3881,8 @@ 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; @@ -3840,7 +3895,8 @@ 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 a283b0193e..f044a88a41 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; @@ -269,7 +276,9 @@ struct V9fsState ino_t root_ino; 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 */ -- 2.11.0