> ...
> Would that (replace slash with space) help?
That sounds perfect. I can change our tooling to replace spaces with
slashes in the protofile. Theoretically you could also have newlines
and tabs and such in filenames but I don't think we need to support
that since it's pretty insane to do in the first place.
On Thu, 2 Feb 2023 at 01:56, Darrick J. Wong <djwong@xxxxxxxxxx> wrote:
>
> On Wed, Jan 25, 2023 at 12:09:28PM +0100, Daan De Meyer wrote:
> > > ...
> >
> > While a "-d" switch would be great to have, it'd also be great if we
> > could make the protofile format work with escaped spaces. That way we
> > can just add escaping for spaces in our tooling that calls mkfs.xfs
> > and we don't have to do ugly version checks on the mkfs binary version
> > to figure out which option to use.
>
> ...which comes at a cost of making *us* figure out some gross hack to
> retrofit that into the protofile format.
>
> The easiest hack I can think of is to amend the protofile parser to
> change any slash in the name to a space before creating the directory
> entry. Slashes aren't allowed (and right now produce a corrupt
> filesystem) so I guess that's the easy way out:
>
> # cat /tmp/protofile
> /
> 0 0
> d--775 1000 1000
> : Descending path /code/t/fstests
> get/isk.sh ---775 1000 1000 /code/t/fstests/getdisk.sh
> ext4.ftrace ---664 1000 1000 /code/t/fstests/ext4.ftrace
> ocfs2.ftrace ---664 1000 1000 /code/t/fstests/ocfs2.ftrace
> xfs.ftrace ---644 1000 1000 /code/t/fstests/xfs.ftrace
> $
> # mkfs.xfs -p /tmp/protofile /dev/sda -f
> meta-data=/dev/sda isize=512 agcount=4, agsize=1298176
> # xfs_db -c 'ls /' /dev/sda
> /:
> 8 128 directory 0x0000002e 1 . (good)
> 10 128 directory 0x0000172e 2 .. (good)
> 12 131 regular 0xd8830694 10 get/isk.sh
> (corrupt)
> 15 132 regular 0x3a30d3ae 11 ext4.ftrace
> (good)
> 18 133 regular 0x3d313221 12 ocfs2.ftrace
> (good)
> 21 134 regular 0x28becaee 10 xfs.ftrace
> (good)
> # xfs_repair -n /dev/sda
> Phase 1 - find and verify superblock...
> Phase 2 - using internal log
> - zero log...
> - scan filesystem freespace and inode maps...
> - found root inode chunk
> Phase 3 - for each AG...
> - scan (but don't clear) agi unlinked lists...
> - process known inodes and perform inode discovery...
> - agno = 0
> entry contains illegal character in shortform dir 128
> would have junked entry "get/isk.sh" in directory inode 128
> - agno = 1
> - agno = 2
> - agno = 3
> - process newly discovered inodes...
> Phase 4 - check for duplicate blocks...
> - setting up duplicate extent list...
> - check for inodes claiming duplicate blocks...
> - agno = 0
> entry contains illegal character in shortform dir 128
> would have junked entry "get/isk.sh" in directory inode 128
> - agno = 2
> - agno = 1
> - agno = 3
> No modify flag set, skipping phase 5
> Phase 6 - check inode connectivity...
> - traversing filesystem ...
> - traversal finished ...
> - moving disconnected inodes to lost+found ...
> Phase 7 - verify link counts...
> No modify flag set, skipping filesystem flush and exiting.
>
> Would that (replace slash with space) help?
>
> --D
>
> > On Wed, 25 Jan 2023 at 02:53, Darrick J. Wong <djwong@xxxxxxxxxx> wrote:
> > >
> > > On Mon, Jan 23, 2023 at 10:13:12PM +0100, Daan De Meyer wrote:
> > > > Hi,
> > > >
> > > > We're trying to use mkfs.xfs's "-p" protofile option for unprivileged
> > > > population of XFS filesystems. However, the man page does not specify
> > > > how to encode filenames with spaces in them. Spaces are used as the
> > > > token delimiter so I was wondering if there's some way to escape
> > > > filenames with spaces in them?
> > >
> > > Spaces in filenames apparently weren't common when protofiles were
> > > introduced in the Fourth Edition Unix in November 1973[1], so that
> > > wasn't part of the specification for them:
> > >
> > > "The prototype file contains tokens separated by spaces or new
> > > lines."
> > >
> > > The file format seems to have spread to other filesystems (minix, xenix,
> > > afs, jfs, aix, etc.) without anybody adding support for spaces in
> > > filenames.
> > >
> > > One could make the argument that the protofile parsing code should
> > > implicitly 's/\// /g' in the filename token since no Unix supports
> > > slashes in directory entries, but that's not what people have been
> > > doing for the past several decades.
> > >
> > > At this point, 50 years later, it probably would make more sense to
> > > clone the mke2fs -d functionality ("slurp up this directory tree") if
> > > there's interest? Admittedly, at this point it's so old that we ought
> > > to rev the entire format.
> > >
> > > [1] https://dspinellis.github.io/unix-v4man/v4man.pdf (page 274)
> > > or https://man.cat-v.org/unix-6th/8/mkfs
> > >
> > > --D
> > >
> > > > Cheers,
> > > >
> > > > Daan De Meyer
