Date: Sat, 12 Apr 2003 17:04:31 -0700 From: Kirk McKusick <mckusick@mckusick.com> To: Marko Zec <zec@tel.fer.hr> Cc: freebsd-stable@freebsd.org Subject: Re: PATCH: Forcible delaying of UFS (soft)updates Message-ID: <200304130004.h3D04Vb5006635@beastie.mckusick.com> In-Reply-To: Your message of "Sat, 12 Apr 2003 03:41:17 %2B0200." <3E976EBD.C3E66EF8@tel.fer.hr>
next in thread | previous in thread | raw e-mail | index | archive | help
I am of the opinion that fsync should work. Applications like `vi' use fsync to ensure that the write of the new file is on stable store before removing the old copy. If that semantic is broken, it would be possible to have neither the old nor the new copy of your file after a crash. I do not consider that acceptable behavior. Further, the fsync call is used to ensure that link/unlink/rename have been completed. So more than just fsync is being affected by your change. Lastly, I often write out a file when I am about to suspend my laptop (for low battery or other reasons) and I really want that file on the disk now. I do not want to have to wait for it to decide at some future time to spin up the disk. I suggest that you make the disabling of fsync a separate option from the rest of your change so that people can decide for themselves whether they want partial savings with working semantics, or greater savings with broken semantics. I am also intrigued by the changes proposed by Ian Dowse that may better accomplish the same goals with less breakage. Kirk McKusick
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?200304130004.h3D04Vb5006635>