Messages in this thread | | | Date | Tue, 22 Nov 2005 13:56:52 -0600 | From | Chris Adams <> | Subject | Re: what is our answer to ZFS? |
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Once upon a time, Alan Cox <alan@lxorguk.ukuu.org.uk> said: > It was a nice try but there is a giant gotcha most people forget. Its > only safe to make this assumption while you have all of the > files/directories in question open.
Tru64 adds a "st_gen" field to struct stat. It is an unsigned int that is a "generation" counter for a particular inode. To get a collision while creating and removing files, you'd have to remove and create a file with the same inode 2^32 times while tar (or whatever) is running. Here's what stat(2) says:
Two structure members in <sys/stat.h> uniquely identify a file in a file system: st_ino, the file serial number, and st_dev, the device id for the directory that contains the file.
[Tru64 UNIX] However, in the rare case when a user application has been deleting open files, and a file serial number is reused, a third structure member in <sys/stat.h>, the file generation number, is needed to uniquely identify a file. This member, st_gen, is used in addition to st_ino and st_dev.
-- Chris Adams <cmadams@hiwaay.net> Systems and Network Administrator - HiWAAY Internet Services I don't speak for anybody but myself - that's enough trouble. - 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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