Bug 88512 - [patch] mount_ext2fs(8) man page has no details on large file and journaling support
Summary: [patch] mount_ext2fs(8) man page has no details on large file and journaling ...
Status: Open
Alias: None
Product: Documentation
Classification: Unclassified
Component: Manual Pages (show other bugs)
Version: Latest
Hardware: Any Any
: Normal Affects Only Me
Assignee: freebsd-doc (Nobody)
Depends on:
Reported: 2005-11-05 02:30 UTC by Ivan Voras
Modified: 2019-01-08 16:39 UTC (History)
2 users (show)

See Also:

file.diff (803 bytes, patch)
2005-11-05 02:30 UTC, Ivan Voras
no flags Details | Diff

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Description Ivan Voras 2005-11-05 02:30:16 UTC
mount_ext2fs(8) is not informative and doesn't mention issues with
large file and journaling support.

man mount_ext2fs
Comment 1 Tom Rhodes freebsd_committer 2008-01-21 20:22:14 UTC
Hi Ivan,

> --- mount_ext2fs.8_old  Mon Oct 31 20:43:17 2005
> +++ mount_ext2fs.8      Mon Oct 31 20:56:45 2005
> @@ -60,6 +60,21 @@
>  .Xr mount 8
>  man page for possible options and their meanings.
>  .El
> +.Sh BUGS
> +Unlike the original Linux implementation, the "large_file"
> +flag is not set automatically when first file larger than
> +2GB is created. Instead,
> +.Xr debugfs 8
> +utility from the e2fsprogs port must be used to manually
> +set the flag with `feature large_file` command. Other than
> +this, large files are fully supported.
> +
> +Support for journaling (ext3) is missing, and filesystems that
> +have it enabled are treated as plain ext2 filesystems.
> +This means that
> +.Xr e2fsck 8
> +will have to be used to repair the journal when the filesystem
> +is to be used in Linux.
>  .Xr mount 2 ,
>  .Xr unmount 2 ,

I'm not sure if this belongs in ext2fs(5) as an implementation
note, or in mount_ext2fs(8) as a compatibility section, or perhaps
just in the mount_ext2fs(8) manual page without it's own section.
But this really doesn't sound like a bug to me.  How about:

Files up to 2GB are supported, larger file support may be
gained by using the
.Nm debugfs
utility found in the e2fsprogs port.
See the
.Op feature
Journaling support is not available and ext3 file systems will
be treated as normal ext2 file systems.
When journal recovery is needed, the
.Nm e2fsck
utility may be used.

Sound good?  Thanks,

Tom Rhodes
Comment 2 Dylan Cochran 2008-01-27 21:52:09 UTC
It's not a bug that FreeBSD only has a ext2fs driver, so it should be
a sort of note for ext2fs(5), it supports ext2 filesystems only,
however, if e2fsck is ran on an ext3 filesystem, it becomes nearly
identical to an ext2 filesystem, and can be mounted. When the journal
feature is in use, it must always be e2fsck'd before mounting, due to
normal filesystem consistancy issues. There are corner cases where it
can be dangerous to not follow that exact procedure, due to a wide
range of ext2 filesystem driver implementations available for
different kernels.

It's become so common of an issue that I have an automatic 'run
e2fsck' response whenever 'ext3' and 'freebsd' are mentioned in the
same sentence.
Comment 3 Eitan Adler freebsd_committer freebsd_triage 2017-12-31 08:00:44 UTC
For bugs matching the following criteria:

Status: In Progress Changed: (is less than) 2014-06-01

Reset to default assignee and clear in-progress tags.

Mail being skipped
Comment 4 Pedro F. Giffuni freebsd_committer 2019-01-08 16:39:18 UTC
mount_ext2fs(8) doesn't exist anymore: ext2 now uses the "new" mount interface so the older manpage didn't correspond to reality.

r342632 did some updates to ext2fs(5) did some important updates mentioning  that journalling and encryption are currently not supported.

I think the handbook could use some updates though so I'll defer this PR to -docs.