Messages in this thread | | | Date | Fri, 10 Feb 2006 10:32:23 -0500 | From | Chris Shoemaker <> | Subject | Re: CD writing in future Linux (stirring up a hornets' nest) |
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On Fri, Feb 10, 2006 at 09:13:44AM -0600, Christopher Friesen wrote: > Joerg Schilling wrote: > >"Christopher Friesen" <cfriesen@nortel.com> wrote: > > >>There's nothing there that says the mapping cannot change with > >>time...just that it has to be unique. > > > > > >If it changes over the runtime of a program, it is not unique from the > >view of that program. > > That depends on what "uniquely identified" actually means.
"The st_ino and st_dev fields taken together uniquely identify the file within the system."
> One possible definition is that at any time, a particular path maps to a > single unique st_ino/st_dev tuple.
The quoted sentence certainly implies _at_least_ that much.
> The other possibility (and this is what you seem to be advocating) is > that a st_ino/st_dev tuple always maps to the same file over the entire > runtime of the system.
However, I don't think this is a reasonable interpretation, and it's clearly _not_ the one that Joerg is implying.
Joerg is claiming that the quoted sentence also implies that _different_ st_ino/st_dev pairs will _always_ identify different files. Taken in just the immediate context of stat.h, this is a very reasonable interpretation.
> This second possibility seems easily disproved. If you delete and > recreate files on a filesystem (assuming nobody has open files in the > filesystem), at some point a new file will end up with the same inode as > an old (deleted) file. The two files are different, but have the same > st_ino/st_dev tuple. > > This leaves the first possibility as the only choice...
If you want to show that his interpretation is incorrent (which it may be for all I know), you need a better argument than this.
-chris
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