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[2003:cf:d74f:9db6:ee80:35b8:6ef7:36e5]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-43d440ed793sm209097485e9.39.2025.03.25.09.07.22 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 25 Mar 2025 09:07:22 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1742918848; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=/gh+riUJHAn43i3neBpAg2kBaqXyzek2lfyG6O1xMac=; b=EGVbQHfMX60THwjfqEH5cRQJs78GQ3QodrOyvSSSChSC4TLn+W02AAyaM1U5xaYucEzvv/ arilaS01RGjF6OCvwypPOsQSjMvpA6+5SzjQ4Vp52eCVkv7kkJra56fKcM8jOASnxs1qqD PWpP7dSM+CHyUXCzml75H+t0FoemveI= X-MC-Unique: I8NwrMEjMb2gAv-656oELw-1 X-Mimecast-MFC-AGG-ID: I8NwrMEjMb2gAv-656oELw_1742918845 X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1742918845; x=1743523645; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=/gh+riUJHAn43i3neBpAg2kBaqXyzek2lfyG6O1xMac=; b=l1vdMMF4LdzXLY9U6viGGEci1ZA52z9Nz6UVRr+Nip4UqYRNjHPtvfcuBAUZgyDyqm j7+AHgpX70PeqtxU4dKR4XTqnC/4oPPl0Z+hcHbg71TfKOAJIlKbf3XFme99YCFT2Uth 2Z9o0Ge/7Ovzpw5Hz5XpVS22SoLnDOq4fMnwbSe7pDubXU5VNoQZD0195WLue+IWw1kJ 8XJpm8pXZQv0nzTbNRpyOtrD4obON/3UtoD1WCMNvvReGnGqwJe6tBSfqF9fSA+7Ig9y G1IvR9eFI6RM8oK/pb9qeKV4dLGs3nSWpU3gxV3eo8ap3fKD1sQyDFxS/xkdS+EBumJh av/g== X-Gm-Message-State: AOJu0YyyF5ULO2WaPA/OmLHtk9vFkvTd8qKoFE6MKEyqmNEEIFQ5bPTj 9FAUeHrANokYj85fqX8nB2ODZ0DS3GujoZPvEyrO2/WI5fyftOTyBh8rHYApvqrsQ31j1CL5GI5 DGGABVH2UEUiEDcwUS66WATdIdQs8DFmIlLAPOWANvhF55C+bM2hv X-Gm-Gg: ASbGncunhfjF+32Rm4MXQSxLAuabOt+4GDPD2dTjpONbrsS2HdXwKxYtSKDyjOrQRsQ xfAa259Kw6SdEioVQtFOWM4CuzxjiqYIX/29gxgPkpUHl3MtiKPPy87vPbD3Xjbfs2isfDhNz7h oZeOFv2bu/zOiR/5YUeOrUq4E2KyNUcAfflxdKL5OlX5rCyXEGkZyn4XA8mWA1bY+8gsVhcqGQl cNXtab8XfgFGJNWpes/AwY4cMKw0uJyA1NV36ytKk3F/klXjPFT4Vxr2uQBXVxhaBr0J/+LLfs2 Cw/yf6jaSJYDNmH78WAKeEggV+hDle6wkRL6RIAeU1faeMgEcrmRRZL9fIcjNtLG2HdK0rjbOA= = X-Received: by 2002:a5d:5f8c:0:b0:391:275a:273f with SMTP id ffacd0b85a97d-3997f8f6089mr14869808f8f.4.1742918845110; Tue, 25 Mar 2025 09:07:25 -0700 (PDT) X-Google-Smtp-Source: AGHT+IF5D0xrWkxlEClrr2p2DL62m+X3C+u0kcvDOMwMgPl9A6x+og7fc3oMXy9l4SSs2p5R7lp33A== X-Received: by 2002:a5d:5f8c:0:b0:391:275a:273f with SMTP id ffacd0b85a97d-3997f8f6089mr14869757f8f.4.1742918844634; Tue, 25 Mar 2025 09:07:24 -0700 (PDT) From: Hanna Czenczek To: qemu-block@nongnu.org Cc: qemu-devel@nongnu.org, Hanna Czenczek , Kevin Wolf Subject: [PATCH 10/15] fuse: Add halted flag Date: Tue, 25 Mar 2025 17:06:50 +0100 Message-ID: <20250325160655.119407-9-hreitz@redhat.com> X-Mailer: git-send-email 2.48.1 In-Reply-To: <20250325160529.117543-1-hreitz@redhat.com> References: <20250325160529.117543-1-hreitz@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=170.10.129.124; envelope-from=hreitz@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H5=0.001, RCVD_IN_MSPIKE_WL=0.001, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, RCVD_IN_VALIDITY_SAFE_BLOCKED=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=unavailable autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: qemu-devel-bounces+importer=patchew.org@nongnu.org X-ZohoMail-DKIM: pass (identity @redhat.com) X-ZM-MESSAGEID: 1742918892031019100 Content-Type: text/plain; charset="utf-8" This is a flag that we will want when processing FUSE requests ourselves: When the kernel sends us e.g. a truncated request (i.e. we receive less data than the request's indicated length), we cannot rely on subsequent data to be valid. Then, we are going to set this flag, halting all FUSE request processing. We plan to only use this flag in cases that would effectively be kernel bugs. (Right now, the flag is unused because libfuse still does our request processing.) Signed-off-by: Hanna Czenczek Reviewed-by: Stefan Hajnoczi --- block/export/fuse.c | 30 ++++++++++++++++++++++++++++++ 1 file changed, 30 insertions(+) diff --git a/block/export/fuse.c b/block/export/fuse.c index e50dd91d3e..3dd50badb3 100644 --- a/block/export/fuse.c +++ b/block/export/fuse.c @@ -53,6 +53,13 @@ typedef struct FuseExport { unsigned int in_flight; /* atomic */ bool mounted, fd_handler_set_up; =20 + /* + * Set when there was an unrecoverable error and no requests should be= read + * from the device anymore (basically only in case of something we wou= ld + * consider a kernel bug) + */ + bool halted; + char *mountpoint; bool writable; bool growable; @@ -69,6 +76,7 @@ static const struct fuse_lowlevel_ops fuse_ops; =20 static void fuse_export_shutdown(BlockExport *exp); static void fuse_export_delete(BlockExport *exp); +static void fuse_export_halt(FuseExport *exp) G_GNUC_UNUSED; =20 static void init_exports_table(void); =20 @@ -99,6 +107,10 @@ static void fuse_dec_in_flight(FuseExport *exp) =20 static void fuse_attach_handlers(FuseExport *exp) { + if (exp->halted) { + return; + } + aio_set_fd_handler(exp->common.ctx, fuse_session_fd(exp->fuse_session), read_from_fuse_export, NULL, NULL, NULL, exp); @@ -316,6 +328,10 @@ static void read_from_fuse_export(void *opaque) FuseExport *exp =3D opaque; int ret; =20 + if (unlikely(exp->halted)) { + return; + } + fuse_inc_in_flight(exp); =20 do { @@ -374,6 +390,20 @@ static void fuse_export_delete(BlockExport *blk_exp) g_free(exp->mountpoint); } =20 +/** + * Halt the export: Detach FD handlers, and set exp->halted to true, preve= nting + * fuse_attach_handlers() from re-attaching them, therefore stopping all f= urther + * request processing. + * + * Call this function when an unrecoverable error happens that makes proce= ssing + * all future requests unreliable. + */ +static void fuse_export_halt(FuseExport *exp) +{ + exp->halted =3D true; + fuse_detach_handlers(exp); +} + /** * Check whether @path points to a regular file. If not, put an * appropriate message into *errp. --=20 2.48.1