Messages in this thread | | | Date | Sun, 26 Oct 2008 12:26:35 +0000 (GMT) | From | Hugh Dickins <> | Subject | Re: tmpfs support of xattrs? |
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On Sat, 25 Oct 2008, Rob MacKinnon wrote:
> The background: So during the initial configuration of a box I enabled > the xattr flags for ext3 and options of xattr in coreutils, and at the > time didn't realize that I'd hit a snag that would finally annoy me > enough after a month of getting a non-fatal error messages from cp "cp: > listing attributes of `/dev/null`: Invalid argument" to spend half a day > researching the cause and a potential solution. > > Setup: udev mounts a tmpfs to /dev then fills it with device nodes. > Problem: the resulting tmpfs has no xattr support. > Therefore: Tmpfs without xattrs, and coreutils and everywhere else with > xattr support, cp freaks. > > Is there sometime in the forseable future when the tmpfs module will > support for xattrs in the stable branch, or should I "holler at the > maintainers of coreutils to fix their broken code in cp". Even better > (and I like this option the most) a little of both?
I've not seen "cp: listing attributes of `/dev/null': Invalid argument" messages (or.. do I have a dim recollection of them once upon a time?). I would certainly get irritated by them if I did, and want to fix them. I tried "cp /dev/null temp" on a few distros just now but not seen it.
I never paid much attention to xattrs myself, but my understanding was that tmpfs has supported xattrs since 2.6.10: from 2.6.10 to 2.6.13 there was CONFIG_TMPFS_XATTR to enable it, then from 2.6.14 to 2.6.18 it was using generic security fallbacks, then from 2.6.19 onwards using generic security fallbacks plus its own enabled by CONFIG_TMPFS_POSIX_ACL.
There's probably various pieces of info we need from you: what distro? what kernel? what coreutils? CONFIG_TMPFS_POSIX_ACL=y? CONFIG_SHMEM=y? what does "attr -l /dev/null" say?
But I may well be missing the _right_ questions to ask: Cc'ed Stephen who made the 2.6.14 changes and Andreas who made the 2.6.19 changes, they may jump to the answer immediately.
Hugh
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