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[2003:cf:d737:d029:edef:7b8d:a744:1ac2]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-48370ac3564sm362444415e9.5.2026.02.18.05.27.34 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 18 Feb 2026 05:27:34 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1771421565; 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=eC1GpsxsI4aDAAkTkGGQOGTuPmmj07fAx5eTswWosPE=; b=OlGT7XtUsRNEtvKfd2F/5rDRX1GO+rdKGkh/q9p2VesNCjAMc8wiBMcZQQQn/gRsnHZRVH TO9OaW5ozcS1FcjwLatoPUn06bgJQOxouoT4gIDSZDmUWMDTVyiHv5H7XKUfxaWbQIGTqR ELNZHakvs2XXRX+1KylXBFG2zwmZkiw= X-MC-Unique: A9ZZAotrOOORghMIuIAPWA-1 X-Mimecast-MFC-AGG-ID: A9ZZAotrOOORghMIuIAPWA_1771421257 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=google; t=1771421257; x=1772026057; darn=nongnu.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=eC1GpsxsI4aDAAkTkGGQOGTuPmmj07fAx5eTswWosPE=; b=stytBGEO65PwvMt2foNCp+nVnTiADfmkjdav+su3jB0OdCqoumzr0/u7KeDaMvMHwf 3l2+FitUfbDdrsjewzkmqPjs7/YdffnP9Ao76YcQSBpXeAa0BaWTCZDi+n8AzFa9NKYA YmhGq/OxhUnc2phke2h5MwwdVirRCi1Q2KcIRLTkqXcbBE7d+H6N6enVrqa0GEGx8C5U kWsFiFhqC75ys9k47qJeuSbagHdnDdkIIiiJHG/UA6IgazGBA1uhojIlR39bbxvtBcp5 GCUYQyCT86SGE0txYuOIgW9WdfWkOMS3wuiSr3airaOy0vtStoKwZeC3BwV6OFQSXOf9 R6oA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1771421257; x=1772026057; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-gg:x-gm-message-state:from :to:cc:subject:date:message-id:reply-to; bh=eC1GpsxsI4aDAAkTkGGQOGTuPmmj07fAx5eTswWosPE=; b=LUkSGu3wYBknwMF6g79GpfVeFZCG9uky/ha1CDN1XrgI7wSsYX8ofpxQl9mzw96SRC sVZXaokm3L4cdl8Du4ktOUaiE7QRAH6FQJGD+TGnaxNaa+7ZotFD/WKP3l9TN/7ovjaz MiEoVimrrS1JV/HumXrlGHASEeYiKohnIN/HhGYL95dTXnm4gQ3dKf5HBmq/YEjmHB/f IGqS8xccs0Uq1Vaa+BjVUB/bbc9UIHzpqGmvuvWjnaSKSjfuQ7KlqLTMKQRflo2Bqz+q 3c6TOZ5o2oZObQUheXuoxJkVmZt7jxh3LDvAGt3IYCrtRjrlNgEeW2bqgR1+wIJQWVep EX3g== X-Gm-Message-State: AOJu0YxtjjTfp8g87JsK4/tNW4/Nr9E7j5YT3UOmaV/Cd+O8vYT8ZPjF Ghnf7MaD9jLIOv27NFqwY8XlT0sCmVfsTebrttaGBs8aC0AbRTWL38pWDfnwRYIiuYwvbJxPlYa zMULVwx99MQE3923v7OQh4kO5WZJICeeWEzGV2UzQVaAIJqtCY8TbmNiS X-Gm-Gg: AZuq6aKyGW8g+crMaCSXj1uLih6jwhGNjYTHCHwiITjdzaN1hVXSBvaK4hseMYo6oVT rQbRPfYP1C5gkjlwIza9Jemd0p4g06JHzFdguqx1ORdfqFLWqaFS6VQFk/1uhfNKA81EQvpqvB6 wQ0TbjNe2LgmsJADgJL8tGVW17qNqwB3Nax+a12vix3wTKPluxly2HbxP1VoQnGfwOs5B9BKWI5 SDkEfIYw/WnsoN02v8NN7obuLnTwyU9J1W8ilwz7WG8vzhebdXe0IeceuXBEuRshsDDbtxeZiQX EVuZH/1kBDQG08JL6ILX1umnUTSELbvezjfeRswr15JjpgHKtdkYOZcKzqZk5Q4jmUIZpTMNkb+ xdK6wzbfOhHb+9k0SQcCjPSUrl0rxndMPvLMw1xWIAk9whmkBt7L41mSq1W8B07rr9eVJVVG1Ao ZaKG7N X-Received: by 2002:a05:600c:620d:b0:480:3bba:1cac with SMTP id 5b1f17b1804b1-48371043046mr263552445e9.6.1771421256833; Wed, 18 Feb 2026 05:27:36 -0800 (PST) X-Received: by 2002:a05:600c:620d:b0:480:3bba:1cac with SMTP id 5b1f17b1804b1-48371043046mr263552055e9.6.1771421256341; Wed, 18 Feb 2026 05:27:36 -0800 (PST) From: Hanna Czenczek To: qemu-block@nongnu.org Cc: qemu-devel@nongnu.org, Hanna Czenczek , Kevin Wolf , Brian Song Subject: [PATCH v4 21/24] fuse: Make shared export state atomic Date: Wed, 18 Feb 2026 14:26:30 +0100 Message-ID: <20260218132633.29748-22-hreitz@redhat.com> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260218132633.29748-1-hreitz@redhat.com> References: <20260218132633.29748-1-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=-0.043, 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_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, RCVD_IN_VALIDITY_SAFE_BLOCKED=0.001, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: qemu development 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: 1771421728862158500 Content-Type: text/plain; charset="utf-8" The next commit is going to allow multi-threaded access to a FUSE export. In order to allow safe concurrent SETATTR operations that can modify the shared st_mode, st_uid, and st_gid, make any access to those fields atomic operations. Signed-off-by: Hanna Czenczek --- block/export/fuse.c | 23 +++++++++++++---------- 1 file changed, 13 insertions(+), 10 deletions(-) diff --git a/block/export/fuse.c b/block/export/fuse.c index aa4f1c0307..162cbdacfc 100644 --- a/block/export/fuse.c +++ b/block/export/fuse.c @@ -157,6 +157,7 @@ typedef struct FuseExport { /* Whether allow_other was used as a mount option or not */ bool allow_other; =20 + /* All atomic */ mode_t st_mode; uid_t st_uid; gid_t st_gid; @@ -267,6 +268,7 @@ static int fuse_export_create(BlockExport *blk_exp, ERRP_GUARD(); /* ensure clean-up even with error_fatal */ FuseExport *exp =3D container_of(blk_exp, FuseExport, common); BlockExportOptionsFuse *args =3D &blk_exp_args->u.fuse; + uint32_t st_mode; int ret; =20 assert(blk_exp_args->type =3D=3D BLOCK_EXPORT_TYPE_FUSE); @@ -335,12 +337,13 @@ static int fuse_export_create(BlockExport *blk_exp, args->allow_other =3D FUSE_EXPORT_ALLOW_OTHER_AUTO; } =20 - exp->st_mode =3D S_IFREG | S_IRUSR; + st_mode =3D S_IFREG | S_IRUSR; if (exp->writable) { - exp->st_mode |=3D S_IWUSR; + st_mode |=3D S_IWUSR; } - exp->st_uid =3D getuid(); - exp->st_gid =3D getgid(); + qatomic_set(&exp->st_mode, st_mode); + qatomic_set(&exp->st_uid, getuid()); + qatomic_set(&exp->st_gid, getgid()); =20 if (args->allow_other =3D=3D FUSE_EXPORT_ALLOW_OTHER_AUTO) { /* Try allow_other =3D=3D true first, ignore errors */ @@ -818,10 +821,10 @@ fuse_co_getattr(FuseExport *exp, struct fuse_attr_out= *out) .attr_valid =3D 1, .attr =3D { .ino =3D 1, - .mode =3D exp->st_mode, + .mode =3D qatomic_read(&exp->st_mode), .nlink =3D 1, - .uid =3D exp->st_uid, - .gid =3D exp->st_gid, + .uid =3D qatomic_read(&exp->st_uid), + .gid =3D qatomic_read(&exp->st_gid), .size =3D length, .blksize =3D blk_bs(exp->common.blk)->bl.request_alignment, .blocks =3D allocated_blocks, @@ -934,15 +937,15 @@ fuse_co_setattr(FuseExport *exp, struct fuse_attr_out= *out, uint32_t to_set, =20 if (to_set & FATTR_MODE) { /* Ignore FUSE-supplied file type, only change the mode */ - exp->st_mode =3D (mode & 07777) | S_IFREG; + qatomic_set(&exp->st_mode, (mode & 07777) | S_IFREG); } =20 if (to_set & FATTR_UID) { - exp->st_uid =3D uid; + qatomic_set(&exp->st_uid, uid); } =20 if (to_set & FATTR_GID) { - exp->st_gid =3D gid; + qatomic_set(&exp->st_gid, gid); } =20 return fuse_co_getattr(exp, out); --=20 2.53.0