Hi, Le 31/08/2020 à 19:42, Jaegeuk Kim a écrit : > Hi, > > On 08/23, Didier Spaier wrote: >> Hi, >> >> thanks for your answer, which leads to more questions and a request. >> >> I will quote only the relevant parts of this answer below. >> >> Le 25/06/2020 à 02:35, Jaegeuk Kim a écrit : >>> On 06/25, Didier Spaier wrote: >> >>>> this email is a follow-up of: >>>> https://www.mail-archive.com/linux-f2fs-devel@lists.sourceforge.net/msg14390.html >> >> ... >> >>>> Q1: Comments about this choice of target devices for f2fs, knowing that >>>> I favor security over performances and that the "auto" option of the >>>> installer is intended for your grand-mother? I am a grand father myself >>>> <smile>. >>> >>> Which security and performance feature do you want to use in the system? >>> For example, mkfs.f2fs requires some options like: >>> - fscrypt : -O encrypt >>> - quota : -O quota >>> - fsverity : -O verity >>> - compression : -O compression -O extra_attr >>> - casefolding : -O casefold -C utf8 >> Do I understand well that these features are defined in f2fs.h? >> In Linux 5.4.60: >> #define F2FS_FEATURE_ENCRYPT 0x0001 >> #define F2FS_FEATURE_BLKZONED 0x0002 >> #define F2FS_FEATURE_ATOMIC_WRITE 0x0004 >> #define F2FS_FEATURE_EXTRA_ATTR 0x0008 >> #define F2FS_FEATURE_PRJQUOTA 0x0010 >> #define F2FS_FEATURE_INODE_CHKSUM 0x0020 >> #define F2FS_FEATURE_FLEXIBLE_INLINE_XATTR 0x0040 >> #define F2FS_FEATURE_QUOTA_INO 0x0080 >> #define F2FS_FEATURE_INODE_CRTIME 0x0100 >> #define F2FS_FEATURE_LOST_FOUND 0x0200 >> #define F2FS_FEATURE_VERITY 0x0400 >> #define F2FS_FEATURE_SB_CHKSUM 0x0800 >> #define F2FS_FEATURE_CASEFOLD 0x1000 >> >> I ask because I don't see them listed in a man page where I would have >> expected to find them, like mkfs.f2fs (8) or mount (8) >> >> I don't see them listed in: >> https://github.com/torvalds/linux/blob/master/Documentation/filesystems/f2fs.rst >> >> ... > > Sorry for inconvenience. Let me enhance documentation a bit.
Thanks in advance. I know that it takes time to update documentation and that you are busy enough already. >>>> Q3. What would be the safest options to include in the relevant line of >>>> /etc/fstab forthe root partition using f2fs? >>> >>> default + any features that you're interested in? >>> We've been using the below option for several years in Android. >>> https://android.googlesource.com/device/google/coral/+/refs/heads/master/fstab.hardware#11 >> >> The mount flags and options are described in f2fs.rst but I don't expect a >> casual user to read that. >> >> So I suggest that all the mount options specific to f2fs be listed in an >> document intended for end users (man f2fs?) as that could help favor its >> adoption by Linux distributions as an alternative to ext4 when relevant. >> >> Maybe you could consult with util-linux devs, as man mount is part of the >> util-linux package; to just add a line to the text quoted below? >> >> FILESYSTEM-SPECIFIC MOUNT OPTIONS >> This section lists options that are specific to particular >> filesystems. Where possible, you should first consult >> filesystem-specific manual pages for details. Some of those pages >> are listed in the following table. >> >> Filesystem(s) Manual page >> btrfs btrfs(5) >> cifs mount.cifs(8) >> ext2, ext3, ext4 ext4(5) >> fuse fuse(8) >> nfs nfs(5) >> tmpfs tmpfs(5) >> xfs xfs(5) >> >> the added line would just be for instance: >> >> f2fs f2fs(8) > > It seems recent "man mount(8)" moves to guide Documentation/filesystems as > well. > But, I think I need to prepare a sort of "man f2fs(5)" in f2fs-tools. I'd be glad for that, should be very useful. > FILESYSTEM-SPECIFIC MOUNT OPTIONS > You should consult the respective man page for the filesystem first. > If you want to know what options the ext4 > filesystem supports, then check the ext4(5) man page. If that > doesn't exist, you can also check the correspond‐ > ing mount page like mount.cifs(8). Note that you might have to > install the respective userland tools. > > The following options apply only to certain filesystems. We sort them > by filesystem. They all follow the -o > flag. > > What options are supported depends a bit on the running kernel. More > info may be found in the kernel source sub‐ > directory Documentation/filesystems. > >> >> Indeed >> >> I know I should propose to contribute writing man f2fs, unfortunately my >> knowledge of f2fs is very close to non existent. >> >> Incidentally, the options listed in >> https://android.googlesource.com/device/google/coral/+/refs/heads/master/fstab.hardware#11 >> indicate that f2fs is only used for the partition mounted as /data. >> >> I don't know Android at all but thought that /system is more or less the >> equivalent of root (/) in other Linux distributions. If that's the case, >> why not us also f2fs for it? Maybe I am fully wrong, please correct me. >> I would be grateful for any pointer to a document explaining the purposes >> of the various mount points in Android as they differ from the FHS: >> https://refspecs.linuxfoundation.org/fhs.shtml > > Android /system is a read-only partition which provides a device boot-up, > while > all the data for applications and users are stored in /data as read-write. > For now, there's no strong motivation to replace the filesystem for /system. > :) > >> >> Best regards, >> >> Didier _______________________________________________ Linux-f2fs-devel mailing list Linux-f2fs-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
