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Thu, 01 Feb 2024 21:51:02 +0100 Message-ID: Date: Fri, 2 Feb 2024 07:20:58 +1030 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 RFC] btrfs-progs: mkfs: optimize file descriptor usage in mkfs.btrfs To: dsterba@suse.cz, Qu Wenruo Cc: Josef Bacik , Anand Jain , linux-btrfs@vger.kernel.org References: <06b40e351b544a314178909772281994bb9de259.1706714983.git.anand.jain@oracle.com> <20240131204800.GB3203388@perftesting> <04a9a9cf-0c77-4f1e-b9f3-12cceeb7ef57@gmx.com> <20240201190712.GW31555@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: <20240201190712.GW31555@twin.jikos.cz> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: quoted-printable X-Provags-ID: V03:K1:VWSbskWjHr1FXN/6VgV1tIa/D26FLK6nHEUcmiKIPKN6BtVK9md lg3Lkole/wjIhNkBDb8zlM5rNLV7Nf/cAc1/p36yH3ThtUmPrmbO4vo6tAsJht9LNB8dyk5 CUSBSkep8pmBBbZEghW88RJXKEZe5Zp15u0/qTNzeNoQuawERPpBNt5pHN3O6U0DYZ0+2Zs 0qvb38UDZ9p+fVMDW+/RA== X-Spam-Flag: NO UI-OutboundReport: notjunk:1;M01:P0:gCW2ViVVOxY=;TrrQl6AbMjzxoo7p5j0m0lbSOjP 0cPD1kW/1yILgLbPP2fquzSxTaWCtfeFK4QXeq1TXVB5wRtMLTbSdvFZuLXlB/tmReimD2FAj Z+4r2uu3khfNvxKlkLMu8JU67ge+4gUjxD/0zNLArNVIsxLA+aYG0eyUFqMULzmuqKXsFTTOn 5LmRUxmfD3VqicJPz0N0SZ5Bv+W3shOwKGjZwv7W2CBu2rVmPEhVmf/MOgbQ2966P6ZVwu8Vs 5t5ElFByY3QmBkwtRxkHZkvEW5NwyBDDlGTkcrnMlp0hI4wntS0Nt/aL2ExwvSGsUq0bKAQWc x4X5eb160odSkxCKVXEyWMLj7hFk2zkVWU06OP/KU7bC1NrN5I2k6Hvq9am8tZH/Vjf0gcQZA wxrFUwGKnZi0Bg+xN6OlPRll/zh1/cQN6E7wCXIT7gtm/i9SmTOFqARM2whjutyuGE/3E+wrY nVnpn2i+Sr+EaNCCiLmROAUXna6QutrthusTjcwC61H4uqhKUNrzZOfz5ZKlrxiwBKaOC8MsZ 2EefELjQpqhJJlD1djnjjXXTsw1vqe+202LIEiSWc9osYM4y49RMrh6Fz8+mwUYm36uzUgWak Az5WGy2WGLFyxpFuqn98W6tIqBLP6YK/73CKMDYrryQ4ysdhp+X59pyybbQGawZGXLuz90Woe 4ceKyBdxy2SSOYeoRgdDovp59CeEPrMemcUpd8Dn8Wnw1xuYJxNlArPCEPigdC8HbDvjMSuy7 WCO6f96L8rm1CdG7xsE/ZcDvTBAvziMcDo8DWky6M7r0Sz+KoWTulCAzLFE+cFLdpi3gmpmTv y/8+ba6fwJOHpG3IptLxdOD35wyHuPpGy7Wf7HY/5lKEw= On 2024/2/2 05:37, David Sterba wrote: > On Thu, Feb 01, 2024 at 07:19:15PM +1030, Qu Wenruo wrote: >> The problem is, even if we change the sequence, it doesn't make much >> difference. >> >> There are several things involved, and most of them are out of our cont= rol: >> >> - The udev scan is triggered on writable fd close(). >> - The udev scan is always executed on the parent block device >> Not the partition device. >> - The udev scan the whole disk, not just the partition >> >> With those involved, changing the nested behavior would not change anyt= hing. >> >> The write in another partition of the same parent block device can stil= l >> triggered a scan meanwhile we're making fs on our partition. > > So this means that creating ext4 on /dev/sda1 and btrfs on /dev/sda2 can > trigger the udev events? And when both mkfs utilities would lock the > device then running them concurrently will fail, right? This could > happen in installation tools that can create different filesystems at > the same time. For ext4, I didn't see any direct flock call, maybe they are using some helpers to do the same work but I'm not 100% sure. > > I wonder if we should add options to assert, skip locking or wait until > it's free. > The "udevadm lock" has various options to do that. I'm pretty sure we can add options like --wait to implement the same deadline behavior for mkfs.btrfs. Thanks, Qu