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[2003:cf:d737:d0cf:29d5:15fb:d605:1d53]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-439dad8d968sm26247465f8f.6.2026.03.09.08.09.58 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 09 Mar 2026 08:09:58 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1773069003; 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=633uGYxCqCqS9HhKtlvq4s6urigO3aDNgdTdJUn3P34=; b=PqE8Arsvk8AuUT2S0dQcrebo56mN9TA/G3noeVg2mNNWlrehpvscpQc36aDItu1JtRi6eJ 1oum5UTb+nZoBLDsURmUqgikXPqPBaj0kM1oy6aNx19SE1OxIbqlLFgsKC8ZfD42O50cef RDRdj+CnRSiJT17mTaf2tdqafgR9j9Y= X-MC-Unique: 8Gx2_sfkPUiwY1z01t2gTw-1 X-Mimecast-MFC-AGG-ID: 8Gx2_sfkPUiwY1z01t2gTw_1773069000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=google; t=1773069000; x=1773673800; 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=633uGYxCqCqS9HhKtlvq4s6urigO3aDNgdTdJUn3P34=; b=m6+3NHEHwA1ipH/A2JBXPM080Dx9SZnHHgD1vfsaQZini2Cr3Rk9Llt1uTLgOGRWBX +BKGdA8ANtNyOGJ+rSXduOEf1UV2MQXYVw9uJKoov0aqxmMZLBt9gfQ8f8b2DEvgfQoG 9bu5L7IotdIKtVTduSdZVdAnP+1Fqz7v2UMcEzSUvpbF88B2n90UtjwDPuHzTvv4ZpZS 9hD6sOu8r32Mn6E8yYLuWGiE6uFY9kfSinVWgFtCe1cQuXvkYP6EH0FiZB2zjcVnWPa9 8ThhnuifOffnv0IP4B5zinKro3H1f7GuuhFYjwh2QLXABSVOhjlc9r6yKKhKGdbWsm9L A7ew== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1773069000; x=1773673800; 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=633uGYxCqCqS9HhKtlvq4s6urigO3aDNgdTdJUn3P34=; b=ngerMhb/86U85Y30pB8MpaM4t5brzWW+z17eNO6uK9YfW8HZtQjjxvlygPXZP8s6Fb CQm1+IiElCap5qF2UHKVCgBVe2IUGs7vwNQ0jc6nzrQF5oPEeyAoDAb06ub/OTOP+Usq jRe33otZLMCvXQe7bFA952srsIYhYD7/gwwz28M0p+d3di30PE0v7k+l+MgLsV/tfnPk 7YlUAu3rHL9BJzyTwTOWNAV/MJQ1Mqqq9KNcdEVsavfjw4MqTDz3unp+2WfelPRcbOV2 1ZuLquGjVdxae/FlHnmZFJkO9YagmZEbfZgqkMnjI5hGTetx98rDAdWU4yoaPUXP7xYM N1uw== X-Gm-Message-State: AOJu0YypYE7O/GTuURlOaFL4xCRpj84RbwX1N1KPG8vUJLvIaXP5yRg+ 5FVWYuykGfOw6KVEuRmVw6kUuJEmIRW53WsOxrHeBHP6QcgAXFOgTLCPzcM3BsZMgvUPY0ta03j FiGwIaOMwpAqcJdt0maXzZTUBLIxyCRK9ijXOrbJ1XAn8StZNykB3dvyD X-Gm-Gg: ATEYQzx/rk08IizyPB7UktTEskU3JX3nUPP3fcZT8svf1GLUHGws7a9dNzCnSTlx7n0 bJ/FaQ4w+7BMCtl5c2uK8+r2+wgDAZx9t/hcwxCWl2pp6kzgDB3C4MC+PbllDUPjbd6kmtrYn+b NkDoC7937Gn3MeWJqoNgQkvjs7jv2HA7HQ321xK3SqZIFXE3SPYcePmieUN397M+/3+owsmp5hV 0FCk4kaGzln9B5KkovjghUT8uoZnjjub34GpA8A4GUW1KM5c512cPkJBMdX6kuTmn0979fGunvw TojoSLaUKSzDduFt4xU+tJECS62AOwJA195ei+J3S78QlsMGnMOnw3KbBZNbz4gw0wCYY9nQR87 x4i8Zs921APmcfPgBFhO4ejjrLqQorm+sHUWyinqIwmFJFim9Cj2KKXcjY9OWKJnbymfqSbEir8 +cKAIc X-Received: by 2002:adf:ff89:0:b0:439:de1d:74c6 with SMTP id ffacd0b85a97d-439de1d76famr14581666f8f.19.1773069000323; Mon, 09 Mar 2026 08:10:00 -0700 (PDT) X-Received: by 2002:adf:ff89:0:b0:439:de1d:74c6 with SMTP id ffacd0b85a97d-439de1d76famr14581620f8f.19.1773068999863; Mon, 09 Mar 2026 08:09:59 -0700 (PDT) From: Hanna Czenczek To: qemu-block@nongnu.org Cc: qemu-devel@nongnu.org, Hanna Czenczek , Kevin Wolf , Brian Song Subject: [PATCH v5 22/25] fuse: Make shared export state atomic Date: Mon, 9 Mar 2026 16:08:53 +0100 Message-ID: <20260309150856.26800-23-hreitz@redhat.com> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260309150856.26800-1-hreitz@redhat.com> References: <20260309150856.26800-1-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=170.10.133.124; envelope-from=hreitz@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -3 X-Spam_score: -0.4 X-Spam_bar: / X-Spam_report: (-0.4 / 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=0.819, RCVD_IN_VALIDITY_SAFE_BLOCKED=0.903, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001 autolearn=no 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: 1773069073907154100 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 1c79411839..fe1b6ad5ff 100644 --- a/block/export/fuse.c +++ b/block/export/fuse.c @@ -156,6 +156,7 @@ 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; @@ -266,6 +267,7 @@ 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); @@ -334,12 +336,13 @@ 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 */ @@ -817,10 +820,10 @@ 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, @@ -903,15 +906,15 @@ 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