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charset="UTF-8" X-BeenThere: linux-erofs@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Development of Linux EROFS file system List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Latchesar Ionkov , Martin Brandenburg , Konstantin Komarov , linux-xfs@vger.kernel.org, "Darrick J. Wong" , Dominique Martinet , Christian Schoenebeck , linux-unionfs@vger.kernel.org, David Howells , Chris Mason , Andreas Dilger , Hans de Goede , Marc Dionne , codalist@coda.cs.cmu.edu, linux-afs@lists.infradead.org, linux-mtd@lists.infradead.org, Mike Marshall , Paulo Alcantara , Amir Goldstein , Eric Van Hensbergen , bug-gnulib@gnu.org, Andreas Gruenbacher , Miklos Szeredi , Richard Weinberger , Mark Fasheh , Hugh Dickins , Benjamin Coddington , Tyl er Hicks , cluster-devel@redhat.com, coda@cs.cmu.edu, linux-mm@kvack.org, Iurii Zaikin , Namjae Jeon , Trond Myklebust , Xi Ruoyao , Shyam Prasad N , ecryptfs@vger.kernel.org, Kees Cook , ocfs2-devel@lists.linux.dev, linux-cifs@vger.kernel.org, Josef Bacik , Tom Talpey , Tejun Heo , Yue Hu , Alexander Viro , Ronnie Sahlberg , David Sterba , Jaegeuk Kim , ceph-devel@vger.kernel.org, Xiubo Li , Ilya Dryomov , OGAWA Hirofumi , Jan Harkes , linux-nfs@vger.kernel.org, linux-ext4@vger.kernel.org, Theodore Ts'o , Joseph Qi , Greg Kroa h-Hartman , v9fs@lists.linux.dev, ntfs3@lists.linux.dev, samba-technical@lists.samba.org, linux-kernel@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net, Steve French , Sergey Senozhatsky , Luis Chamberlain , devel@lists.orangefs.org, Anna Schumaker , Jan Kara , Bo b Peterson , linux-fsdevel@vger.kernel.org, Andrew Morton , Sungjong Seo , linux-erofs@lists.ozlabs.org, linux-btrfs@vger.kernel.org, Joel Becker Errors-To: linux-erofs-bounces+linux-erofs=archiver.kernel.org@lists.ozlabs.org Sender: "Linux-erofs" Jeff Layton wrote: > > Surely this is a safe choice as it moves the responsibility to the sysa= dmin > > and the cases where finegrained timestamps are required. But I kind of > > wonder how is the sysadmin going to decide whether mgtime is safe for h= is > > system or not? Because the possible breakage needn't be obvious at the > > first sight... >=20 > That's the main reason I really didn't want to go with a mount option. > Documenting that may be difficult. You could document it like this: The mgtime option enables more precise modification times (mtime) on some files, together with an optimization that limits the amount of metadata changes. Note that this option may, in some cases, after writing to file F1 and then writing to file F2, report a lower mtime for F2 than for F2. Enabling this option may be useful on file systems shared via NFS. The safe choice is to disable this option. =46or me as a user, there's no need to go into more details than that. It's important to have this mount option, for people who want maximum reliability. Personally, I always enable the 'strictatime' option on all ext4 mounts, since 'relatime' optimizes too much for my use-cases. If I fear wrong results of "make" runs, I will definitely opt for the safe choice regarding mgtime as well =E2=80=94 since I don't want to spend hours debugging binaries that were built incorrectly from correct source code. Bruno