Messages in this thread | | | Date | Wed, 22 Jul 2020 21:10:26 +0200 | From | Greg KH <> | Subject | Re: [PATCH 1/2] f2fs: add sysfs symbolic link to kobject with volume name |
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On Wed, Jul 22, 2020 at 10:24:37AM -0700, Jaegeuk Kim wrote: > On 07/22, Greg KH wrote: > > On Wed, Jul 22, 2020 at 09:43:56AM -0700, Jaegeuk Kim wrote: > > > On 07/19, Greg KH wrote: > > > > On Sun, Jul 19, 2020 at 02:44:08PM +0900, Daeho Jeong wrote: > > > > > From: Daeho Jeong <daehojeong@google.com> > > > > > > > > > > Added a symbolic link directory pointing to its device name > > > > > directory using the volume name of the partition in sysfs. > > > > > (i.e., /sys/fs/f2fs/vol_#x -> /sys/fs/f2fs/sda1) > > > > > > > > No, please no. > > > > > > > > That is already created today for you in /dev/disk/ The kernel does not > > > > need to do this again. > > > > > > > > If your distro/system/whatever does not provide you with /dev/disk/ and > > > > all of the symlinks in there, then work with your distro/system/whatever > > > > to do so. > > > > > > I don't get the point, since /dev/disk points device node, not any sysfs entry. > > > Do you mean we need to create symlink to /sys/fs/f2fs/dm-X in /dev/disk? > > > > Huh, no! It's all done for you today automagically by userspace: > > > > $ tree /dev/disk/by-label/ > > /dev/disk/by-label/ > > ├── boot -> ../../sda1 > > ├── fast_disk -> ../../md0 > > ├── root -> ../../sda2 > > └── stuff -> ../../dm-0 > > > > Look on your laptop/desktop/server today for those, there's lots of > > symlinks in /dev/disk/ > > What I mean is "creating symlink from *userspace*", but the concern is > "/dev/" looks like being used for device nodes only, not sysfs.
That is correct, that is what /dev/ is for, not sysfs.
> > > > Again, no need to do this on a per-filesystem-basis when we already have > > > > this around for all filesystems, and have had it for 15+ years now. > > > > > > Could you point out where we can get this? And, the label support depends > > > on per-filesystem design. I'm not sure how this can be generic enough. > > > > Userspace knows how to read labels on a per-filesystem-basis and does so > > just fine. That's how it creates those symlinks, no kernel support is > > needed. > > > > This has been implemented for 15+ years now, it's not a new thing... > > > > Now if your embedded system doesn't support it, that's the userspace of > > that system's fault, it's not the kernel's fault at all. Go fix your > > userspace if you want those things. > > I'm not talking about whose fault tho. :) By any chance, could you please > suggest a good location to create a symlink for this sysfs entry?
There is no need for such a sysfs entry, that's what I am trying to say. Userspace already has all of the needed information here, do not try to add filesystem-specific stuff like this, unless you somehow are going to do it for all filesystems :)
thanks,
gregt k-h
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