hard links to files on other filesystems disallowed: why?
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From: Rahul on 21 Feb 2010 21:41 Marten Kemp <marten.kemp(a)thisplanet-link.net> wrote in news:hlrcc1$720$1 @speranza.aioe.org: > > Cross-FS-hardlinks could be special entries containing the volser > where the FS is to be found and the inode within the FS. > > I'd be willing to wager that cross-FS-hardlinks weren't implemented > because that would create a special type of pointer. > Now that's an interesting line of thought: Are cross-FS hardlinks frowned upon in most other OS's too besides Linux? How about other *nix es? Or even totally different OS's. -- Rahul
From: Rahul on 21 Feb 2010 21:46 Florian Diesch <diesch(a)spamfence.net> wrote in news:712957-cmg.ln1 @mid.florian-diesch.de: > That's often done because creating symlinks is an atomic action (in > contrast to writing the data into a file). > What about just "touching" a file. Isn't that an equally atomic operation? -- Rahul
From: Robert Heller on 22 Feb 2010 08:24 At Mon, 22 Feb 2010 02:46:52 +0000 (UTC) Rahul <nospam(a)nospam.invalid> wrote: > > Florian Diesch <diesch(a)spamfence.net> wrote in news:712957-cmg.ln1 > @mid.florian-diesch.de: > > > That's often done because creating symlinks is an atomic action (in > > contrast to writing the data into a file). > > > > What about just "touching" a file. Isn't that an equally atomic operation? No. And merely touching the file stores no information. Creating a symlink to 'nowhere' not only creates the link, it also creates the path-like datum *at the same time*. Compare: #include <unistd.h> char *makesomedatum(); int status = symlink(makesomedataum(),"path/to/data"); with #include <stdio.h> char *makesomedatum(); FILE *fp = fopen("path/to/data","w"); fprintf(fp,"%s\n",makesomedatum()); fclose(fp); > -- Robert Heller -- 978-544-6933 Deepwoods Software -- Download the Model Railroad System http://www.deepsoft.com/ -- Binaries for Linux and MS-Windows heller(a)deepsoft.com -- http://www.deepsoft.com/ModelRailroadSystem/
From: Marten Kemp on 22 Feb 2010 08:43 John Hasler wrote: > Marten writes: >> Use a 'volser' (volume serial number) to identify partitions as is >> done in some mainframe OSen. > > Linux already has filesystem UUIDs. > >> I'd much rather deal with 'doofus-root' than with 'hda1' in fstab, for >> example. > > Use volume labels. Yes. -- -- Marten Kemp (Fix ISP to reply) You can't help being ignorant 'cause there's always something you don't know; what you can't be is stupid.
From: Marten Kemp on 22 Feb 2010 09:08
Rahul wrote: > Marten Kemp <marten.kemp(a)thisplanet-link.net> wrote in news:hlrcc1$720$1 > @speranza.aioe.org: > >> Cross-FS-hardlinks could be special entries containing the volser >> where the FS is to be found and the inode within the FS. >> >> I'd be willing to wager that cross-FS-hardlinks weren't implemented >> because that would create a special type of pointer. > > Now that's an interesting line of thought: Are cross-FS hardlinks frowned > upon in most other OS's too besides Linux? How about other *nix es? Or even > totally different OS's. zVM doesn't have multi-volume user file systems[0]; neither does zOS (except possibly for TEMP files), in my limited and quite outdated knowledge. I don't know enough about OS400 to make a guess. [0] Well, there's the Shared File System but that's more like a LVM 'volume.' -- -- Marten Kemp (Fix ISP to reply) You can't help being ignorant 'cause there's always something you don't know; what you can't be is stupid. |