On 20 February 2015 at 13:32, Andreas Dilger <adilger@xxxxxxxxx> wrote: > On Feb 20, 2015, at 1:50 AM, Michael Kerrisk <mtk.manpages@xxxxxxxxx> wrote: >> >> Hello Ted, >> >> Based on your commit message 0ae45f63d4e, I I wrote the documentation >> below for MS_LAZYTIME, to go into the mount(2) man page. Could you >> please check it over and let me know if it's accurate. In particular, >> I added pieces marked with "*" below that were not part of the commit >> message and I'd like confirmation that they're accurate. >> >> Thanks, >> >> Michael >> >> [[ >> MS_LAZYTIME (since Linux 3.20) >> Only update filetimes (atime, mtime, ctime) on the in- >> memory version of the file inode. The on-disk time‐ >> stamps are updated only when: >> >> (a) the inode needs to be updated for some change unre‐ >> lated to file timestamps; >> >> (b) the application employs fsync(2), syncfs(2), or >> sync(2); >> >> (c) an undeleted inode is evicted from memory; or >> >> * (d) more than 24 hours have passed since the i-node was >> * written to disk. >> >> This mount option significantly reduces writes to the >> inode table for workloads that perform frequent random >> writes to preallocated files. >> >> * As at Linux 3.20, this option is supported only on ext4. > > I _think_ that the lazytime mount option is generic for all filesystems. > I believe ext4 has an extra optimization for it, but that's it. Ah yes, looking at the code again, that makes sense. I think you're right, and I've struck that last sentence. Thanks, Andreas. Cheers, Michael -- Michael Kerrisk Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/ Linux/UNIX System Programming Training: http://man7.org/training/ -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
