On 28 apr 2010, at 14.06, Edward Ned Harvey wrote: >> From: zfs-discuss-boun...@opensolaris.org [mailto:zfs-discuss- >> boun...@opensolaris.org] On Behalf Of Edward Ned Harvey >> >> Look up the inode number of README. (for example, ls -i README) >> (suppose it’s inode 12345) >> find /tank/.zfs/snapshot -inum 12345 >> >> Problem is, the find command will run for a long time. >> >> Is there any faster way to find the file name(s) when all you know is >> the inode number? (Actually, all you know is all the info that’s in >> the present directory, which is not limited to inode number; but, inode >> number is the only information that I personally know could be useful.) > > Due to lack of response, and based on my personal knowledge, and lack of any > useful response anywhere else I've asked this question, I'm drawing the > conclusion it's not possible to quickly lookup the name(s) of an inode. > > Which means in ZFS, if you want to find the previous snapshots of some > file/directory that was renamed/moved, there are only two possibilities: > > Assume the name and location didn't change. So you can quickly "ls" or > "stat" specific already-known name(s) in the snapshot directories. > - or - > Walk all the trees of all the snapshots searching for inode X. Which would > be probably extremely slow. (Probably many hours to complete, in a typical > small business fileserver, linearly dependent on number of files in the > filesystem and number of snapshots to traverse.) > > BTW, this is not an issue for Ontap. Which is to say, yes it's absolutely > possible to maintain reverse inode lookup tables too, but apparently not > implemented in ... other filesystems including ZFS.
What indicators do you have that ONTAP/WAFL has inode->name lookup functionality? I don't think it has any such thing - WAFL is pretty much an UFS/FFS that does COW instead of in-place writing, the main difference is that inodes are written to special inode files rather than specific static areas. Directories I believe works very much like UFS/FFS directories. But I may have misunderstood something and be wrong. > I think an inode --> name lookup table would be useful in something like > zhist. And it's one way of solving this problem without violating any > Ontap-style .snapshot directory patents. So maybe this would be a good > thing to request in future versions of ZFS. I must be missing something or maybe I am just plain stupid (both are probable), and just out of curiosity: What is the exact problem you are trying to solve? Providing a move/rename history? Is there a specific use case? /ragge _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
