Messages in this thread | | | Date | Thu, 12 Feb 2009 22:23:04 +0100 | From | Jan Kara <> | Subject | Re: vfs: Add MS_FLUSHONFSYNC mount flag |
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On Thu 12-02-09 11:13:37, Eric Sandeen wrote: > Fernando Luis Vázquez Cao wrote: > > This mount flag will be used to determine whether the block device's write > > cache should be flush or not on fsync()/fdatasync(). > > > > Signed-off-by: Fernando Luis Vazquez Cao <fernando@oss.ntt.co.jp> > > --- > > Again, apologies for chiming in late. > > But wouldn't it be better to make this a block device property rather > than a new filesystem mount option? Hum, that's an interesting idea. Yes, probably it makes even more sence than a global mount option.
> That way the filesystem can always do "the right thing" and call the > blkdev flush on fsync. > > The block device *could* choose to ignore this in hardware if it knows > it's built with a nonvolatile write cache or if it has no write cache. > > Somewhere in the middle, if an administrator knows they have a UPS they > trust and hardware that stays connected to it, they could tune the bdev > to ignore these flush requests. > > Also that way if you have 8 partitions on a battery-backed blockdev, you > can tune it once, instead of needing to mount all 8 filesystems with the > new option. Yes, but OTOH we should give sysadmin a possibility to enable / disable it on just some partitions. I don't see a reasonable use for that but people tend to do strange things ;) and here isn't probably a strong reason to not allow them.
Honza -- Jan Kara <jack@suse.cz> SUSE Labs, CR -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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