On 06/02/2010 11:02 AM, Sunil Mushran wrote: > On 06/02/2010 12:28 AM, H. Peter Anvin wrote: >> On 06/01/2010 12:49 PM, tytso@xxxxxxx wrote: >>> On Tue, Jun 01, 2010 at 12:32:29PM -0700, Sunil Mushran wrote: >>>> >>>> We (ocfs2) are looking to add a new attribute to denote files that >>>> have a fixed allocation on disk. But at the same time, allow writes >>>> that do not change the allocation on disk. No truncating, extending, >>>> filling holes, etc. We were thinking of calling it "Static" files. >>> >>> That's an interesting set of semantics, and it might make sense to >>> conflate that with a local disk "don't move or defrag" the file >>> option. I'm not crazy with the name "static", since it could mean a >>> number of other things in other contexts, but I admit I can't think of >>> a better name. >>> >> >> For what it's worth, this sort of seems to be what one would expect if >> a file is *both* "fixed" and "immutable". > > "Immutable" means the contents do not change. But the file mappings > could change. > > "Fixed mapping" means the mappings do not change but contents > could (as long as the ondisk mappings don't). > > "Fixed metadata" means the entire inode (mappings included) cannot > change but the contents could (as long as the ondisk mappings don't). > (This does have the side effect of allowing writes without touching the > mtime. Like XFS' invisible i/o.) > Actually, if you're going to have three flags you might as well make them orthogonal. That is, separate "fixed contents", "fixed mappings", "fixed metadata" -- and don't consider the mapping as metadata for this purpose. -hpa -- 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
