Re: VFS 64-bit clean

Theodore Y. Ts'o (tytso@MIT.EDU)
Fri, 27 Feb 1998 20:25:46 -0500

Date: Thu, 26 Feb 1998 23:57:20 GMT
From: "Stephen C. Tweedie" <>

I would strongly recommend that we use i_faddr instead of i_dir_acl for
this, since fragments are currently *completely* unused in all ext2fs
variants, whereas there are patches waiting to be merged which use the
acl fields.

I would agree with Albert Calahan that we should use i_dir_acl. We can
make sure the patches don't break by using #define's for i_dir_acl.

I'm opposed to implementing fragments in ext2fs since we can get good
performance even at smaller block sizes by using the intelligent IO
clustering code, so there's no reason to go out of our way performing
the amazing hack which is ffs fragments. If we don't care about
fragments, then this field is completely open to our reuse.

I agree with you that we shouldn't ever do fragments, but rather improve
our block allocation strategies and use extents to reduce the need for
indirect blocks and just use small block sizes.

However, I'd prefer to keep i_faddr in reserve for some future extension
when we really need the extra 32-bit field in the inode, since space in
the inode rather precious. Albert is right that we'll never need
directories greater than 2GB, so reusing i_dir_acl for non-directory
inodes seems like the most efficient way to use that inode field.

- Ted

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