Messages in this thread |  | | Date | Thu, 8 Nov 2001 01:26:10 +0000 | From | Stephen Tweedie <> | Subject | Re: [Acl-Devel] Re: [RFC][PATCH] extended attributes |
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Hi,
On Wed, Nov 07, 2001 at 02:19:56PM +1100, Nathan Scott wrote: > On Wed, Nov 07, 2001 at 02:32:18AM +0100, Andi Kleen wrote: > > EA_FIRST_ENTRY to reset the fd the first entry, EA_READ_ENTRY to > > read the next one. > > I'm not sure this would work for the extattr/lextattr variants where > we don't have an fd to hold the state.
> eg. the opening of the file before allowing a list operation could > have implications for XFSs DMAPI support (open might recall data from > tape),
There are other much more immediate obstacles: opening /dev/* is not possible if the devices beneath the inodes don't exist.
O_OPENONLY (implying neither read nor write access) to get a stub file handle for such inodes is possible, if a bit hackish. There's a problem in the kernel there --- kernel file descriptor operations on "special" inodes such as named sockets/pipes or device nodes don't pass file operations on to the underlying filesystem.
As long as you're doing the ACL stuff via inode operations internally, that's not a problem. However, inode operations generally don't take a file descriptor as an argument so you don't have access to the cursor in that case.
The DMAPI and special inode problems go away if you don't demand a file descriptor to the file. (Having a file descriptor that specifically belongs to the ACL stream is a different matter entirely.)
--Stephen - 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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