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Thu, 04 Jul 2024 02:19:55 +0200 Message-ID: Date: Thu, 4 Jul 2024 09:49:52 +0930 Precedence: bulk X-Mailing-List: linux-btrfs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] btrfs-prog: scrub: print message when scrubbing a read-only filesystem without r option To: dsterba@suse.cz Cc: Li Zhang , linux-btrfs@vger.kernel.org References: <1720028821-3094-1-git-send-email-zhanglikernel@gmail.com> <20240704001309.GV21023@twin.jikos.cz> Content-Language: en-US From: Qu Wenruo Autocrypt: addr=quwenruo.btrfs@gmx.com; keydata= xsBNBFnVga8BCACyhFP3ExcTIuB73jDIBA/vSoYcTyysFQzPvez64TUSCv1SgXEByR7fju3o 8RfaWuHCnkkea5luuTZMqfgTXrun2dqNVYDNOV6RIVrc4YuG20yhC1epnV55fJCThqij0MRL 1NxPKXIlEdHvN0Kov3CtWA+R1iNN0RCeVun7rmOrrjBK573aWC5sgP7YsBOLK79H3tmUtz6b 9Imuj0ZyEsa76Xg9PX9Hn2myKj1hfWGS+5og9Va4hrwQC8ipjXik6NKR5GDV+hOZkktU81G5 gkQtGB9jOAYRs86QG/b7PtIlbd3+pppT0gaS+wvwMs8cuNG+Pu6KO1oC4jgdseFLu7NpABEB AAHNIlF1IFdlbnJ1byA8cXV3ZW5ydW8uYnRyZnNAZ214LmNvbT7CwJQEEwEIAD4CGwMFCwkI BwIGFQgJCgsCBBYCAwECHgECF4AWIQQt33LlpaVbqJ2qQuHCPZHzoSX+qAUCY00iVQUJDToH pgAKCRDCPZHzoSX+qNKACACkjDLzCvcFuDlgqCiS4ajHAo6twGra3uGgY2klo3S4JespWifr BLPPak74oOShqNZ8yWzB1Bkz1u93Ifx3c3H0r2vLWrImoP5eQdymVqMWmDAq+sV1Koyt8gXQ XPD2jQCrfR9nUuV1F3Z4Lgo+6I5LjuXBVEayFdz/VYK63+YLEAlSowCF72Lkz06TmaI0XMyj jgRNGM2MRgfxbprCcsgUypaDfmhY2nrhIzPUICURfp9t/65+/PLlV4nYs+DtSwPyNjkPX72+ LdyIdY+BqS8cZbPG5spCyJIlZonADojLDYQq4QnufARU51zyVjzTXMg5gAttDZwTH+8LbNI4 mm2YzsBNBFnVga8BCACqU+th4Esy/c8BnvliFAjAfpzhI1wH76FD1MJPmAhA3DnX5JDORcga CbPEwhLj1xlwTgpeT+QfDmGJ5B5BlrrQFZVE1fChEjiJvyiSAO4yQPkrPVYTI7Xj34FnscPj /IrRUUka68MlHxPtFnAHr25VIuOS41lmYKYNwPNLRz9Ik6DmeTG3WJO2BQRNvXA0pXrJH1fN GSsRb+pKEKHKtL1803x71zQxCwLh+zLP1iXHVM5j8gX9zqupigQR/Cel2XPS44zWcDW8r7B0 q1eW4Jrv0x19p4P923voqn+joIAostyNTUjCeSrUdKth9jcdlam9X2DziA/DHDFfS5eq4fEv ABEBAAHCwHwEGAEIACYCGwwWIQQt33LlpaVbqJ2qQuHCPZHzoSX+qAUCY00ibgUJDToHvwAK CRDCPZHzoSX+qK6vB/9yyZlsS+ijtsvwYDjGA2WhVhN07Xa5SBBvGCAycyGGzSMkOJcOtUUf tD+ADyrLbLuVSfRN1ke738UojphwkSFj4t9scG5A+U8GgOZtrlYOsY2+cG3R5vjoXUgXMP37 INfWh0KbJodf0G48xouesn08cbfUdlphSMXujCA8y5TcNyRuNv2q5Nizl8sKhUZzh4BascoK DChBuznBsucCTAGrwPgG4/ul6HnWE8DipMKvkV9ob1xJS2W4WJRPp6QdVrBWJ9cCdtpR6GbL iQi22uZXoSPv/0oUrGU+U5X4IvdnvT+8viPzszL5wXswJZfqfy8tmHM85yjObVdIG6AlnrrD In-Reply-To: <20240704001309.GV21023@twin.jikos.cz> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: quoted-printable X-Provags-ID: V03:K1:7X0lfkNZYpw/k/5Q8bpD0oYlRSqP5s/jCOLF/ZyLhI7GrfKAY0u U/OAjsxHOO/Pt/QCQudGq27A+2KxvoEKk0DcUU8jGst4hhnLGC+9Nj6yBgIXjVaswsBkAcV jp86jugr9GDXy4qWoqUQquRzeK9RzCMjxvFdAwYqLJyygOeD5U+X/WYsxunRcoTdxevHCkB n1tg6TUOToA0GYxiHoJ3w== X-Spam-Flag: NO UI-OutboundReport: notjunk:1;M01:P0:oGw7dua7khw=;gpbV0rex05FnCYesNsET41wAuVG Q2fJgU0Pbza2mNnKLemQTXf1O0hIhwEcJmLdhL8IvoA2thHtRHo6h/hm+YPvUbsdeRirmQaEY Ye2UJId4IMjxb4dw2hwv8zZDz/xO26uAT0zWmiiY5KBSfyUS96/pf/baNsHZGTH0bQByGI/ur jNE7RkW7hSfUmNsYF7WtQIBK3f+QDZizLBPL6Pa/yLuLdAE693Eu8zK8pewdP963iFjCp33AW AXnZY5/DErtRMlgWePVd/T3l8/IDbvfIe4DkdVi5YnRJ+vCZcy8NF8ciTZ+KaFEyjSvHqZ75r 78Or/ot7jck8L734NJXqsejefP3cpRUVLugtrnBx0kWB1ize13c4cdomePx0yirxz+6JsdECu ClQEQX0Y3TRCYhOERSFrKBlRrgEVNbcvfgrtVm7Epg74eiRM5RV5OlqkMokOYBB8B/GaVK7LS LWVYSntKiSyOeCBdlE9GPZdloin5rQ19v8fB9R0+cQopiaCXvL8NT7rZzZgPItVlZ9Ga5wMTC 3mDWiueZhmU1WgNfia5W7u1ou3Emr9Z+mheoBXN7gi6pFQqp9dxGid44OVnQQq3d1SyX8a2TV hqxjiM0LB3z6bOHsAHsN84vxAvUUshIDkegq6IaX88UyiHseSBV+W74YTXA+ivq7RweL4A4Mr 3oYJycNOQPHqDoevLDjf1AAtc7aNAUDAnlLMAkWkRqXtDyAv8Tm1f1RpjIroqb3cahltvn6So LTesomskwdkP9UWInLLiXWYLi3Ci2PGYNXQIOwT9WN949KwfXFGmeYmZTeF6wDcE3TneU1Tnf EV5k0l+i4Q64ArHhSLp3vGsqObEdN7PoInLeeVzupFqns= =E5=9C=A8 2024/7/4 09:43, David Sterba =E5=86=99=E9=81=93: > On Thu, Jul 04, 2024 at 08:56:47AM +0930, Qu Wenruo wrote: >>> --- a/cmds/scrub.c >>> +++ b/cmds/scrub.c >>> @@ -957,7 +957,10 @@ static void *scrub_one_dev(void *ctx) >>> warning("setting ioprio failed: %m (ignored)"); >>> >>> ret =3D ioctl(sp->fd, BTRFS_IOC_SCRUB, &sp->scrub_args); >>> - pr_verbose(LOG_DEFAULT, "scrub ioctl devid:%llu ret:%d errno:= %d\n",sp->scrub_args.devid, ret, errno); >>> + if (ret){ >>> + pr_verbose(LOG_DEFAULT, "scrub on devid %llu failed ret=3D%d errno= =3D%d (%m)\n", >>> + sp->scrub_args.devid, ret, errno); >>> + } >> >> Doing direct output inside a thread can lead to race of the output. > > We'd have to communicate the ioctl start errors back to the main thread, > or rely on internal locking of printf, that it can race is possible but > as long as the string is printed in one go we'll get only lines > reordered. > >> And we do not know if the scrub ioctl would return error early or run >> for a long long time, that's the dilemma. >> >> I'm wondering if it's possible to do a blkid/mountinfo based probe. >> Then it would avoid the possible output race and error out earilier. > > We can detet read/write status of the block devices. I'm not sure about > the mount info, what function can we use for that? > E.g, setmntent() and getmntent() used inside check_mounted_where()? Since mntent structure provides mnt_opts, it should not be that hard to find if the destination mount point is mounted ro? Thanks, Qu