linux/Documentation/filesystems
Chris Novakovic c04d2cb200 ipconfig: Write NTP server IPs to /proc/net/ipconfig/ntp_servers
Distributed filesystems are most effective when the server and client
clocks are synchronised. Embedded devices often use NFS for their
root filesystem but typically do not contain an RTC, so the clocks of
the NFS server and the embedded device will be out-of-sync when the root
filesystem is mounted (and may not be synchronised until late in the
boot process).

Extend ipconfig with the ability to export IP addresses of NTP servers
it discovers to /proc/net/ipconfig/ntp_servers. They can be supplied as
follows:

 - If ipconfig is configured manually via the "ip=" or "nfsaddrs="
   kernel command line parameters, one NTP server can be specified in
   the new "<ntp0-ip>" parameter.
 - If ipconfig is autoconfigured via DHCP, request DHCP option 42 in
   the DHCPDISCOVER message, and record the IP addresses of up to three
   NTP servers sent by the responding DHCP server in the subsequent
   DHCPOFFER message.

ipconfig will only write the NTP server IP addresses it discovers to
/proc/net/ipconfig/ntp_servers, one per line (in the order received from
the DHCP server, if DHCP autoconfiguration is used); making use of these
NTP servers is the responsibility of a user space process (e.g. an
initrd/initram script that invokes an NTP client before mounting an NFS
root filesystem).

Signed-off-by: Chris Novakovic <chris@chrisn.me.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-04-24 13:40:42 -04:00
..
caching fscache: Pass object size in rather than calling back for it 2018-04-06 14:05:14 +01:00
cifs Update README file for cifs.ko 2018-04-01 20:24:39 -05:00
configfs
nfs ipconfig: Write NTP server IPs to /proc/net/ipconfig/ntp_servers 2018-04-24 13:40:42 -04:00
pohmelfs
00-INDEX
9p.txt
adfs.txt
affs.txt
afs.txt afs: Implement @sys substitution handling 2018-04-09 21:12:31 +01:00
autofs4-mount-control.txt
autofs4.txt Fix up over-eager 'wait_queue_t' renaming 2017-07-10 11:40:19 -07:00
automount-support.txt
befs.txt
bfs.txt Tigran has moved 2017-05-12 15:57:15 -07:00
btrfs.txt
ceph.txt ceph: quota: report root dir quota usage in statfs 2018-04-02 11:17:53 +02:00
coda.txt
conf.py docs-rst: convert filesystems book to ReST 2017-05-16 08:44:08 -03:00
cramfs.txt cramfs: rehabilitate it 2017-10-15 00:47:23 -04:00
dax.txt powerpc/cell: Remove axonram driver 2018-01-28 17:00:36 +11:00
debugfs.txt
devpts.txt
directory-locking
dlmfs.txt
dnotify.txt Documentation: fix selftests related file refs 2017-10-19 12:58:21 -06:00
ecryptfs.txt
efivarfs.txt
exofs.txt
ext2.txt fs/*/Kconfig: drop links to 404-compliant http://acl.bestbits.at 2018-01-01 12:45:37 -07:00
ext3.txt
ext4.txt Only miscellaneous cleanups and bug fixes for ext4 this cycle. 2018-02-03 13:49:22 -08:00
f2fs.txt f2fs: introduce a new mount option test_dummy_encryption 2018-03-17 14:02:57 +09:00
fiemap.txt
files.txt
fscrypt.rst fscrypt: document symlink length restriction 2018-01-11 23:30:09 -05:00
fuse.txt
gfs2-glocks.txt GFS2: Minor improvements to comments and documentation 2018-04-12 10:07:51 -07:00
gfs2-uevents.txt
gfs2.txt
hfs.txt
hfsplus.txt
hpfs.txt
index.rst fscrypt: add a documentation file for filesystem-level encryption 2017-10-31 13:49:24 -04:00
inotify.txt
isofs.txt
jfs.txt
Locking vfs: add flags to d_real() 2017-09-04 21:42:22 +02:00
locks.txt
mandatory-locking.txt
ncpfs.txt
nilfs2.txt MAINTAINERS, nilfs2: change project home URLs 2018-01-13 10:42:48 -08:00
ntfs.txt
ocfs2-online-filecheck.txt
ocfs2.txt
omfs.txt
orangefs.txt Orangefs: documentation updates 2018-04-04 14:05:48 -04:00
overlayfs.txt ovl: update documentation w.r.t "xino" feature 2018-04-12 12:04:51 +02:00
path-lookup.md locking/atomics, doc/filesystems: Convert ACCESS_ONCE() references 2017-10-25 11:01:05 +02:00
path-lookup.txt
porting vfs: grab the lock instead of blocking in __fd_install during resizing 2017-11-05 18:58:07 -05:00
proc.txt proc, coredump: add CoreDumping flag to /proc/pid/status 2017-11-17 16:10:00 -08:00
qnx6.txt
quota.txt
ramfs-rootfs-initramfs.txt
relay.txt
romfs.txt
seq_file.txt
sharedsubtree.txt
spufs.txt
squashfs.txt
sysfs-pci.txt PCI: Add pci_mmap_resource_range() and use it for ARM64 2017-04-20 08:47:47 -05:00
sysfs-tagging.txt
sysfs.txt kallsyms: remove print_symbol() function 2018-01-16 16:59:55 +01:00
sysv-fs.txt
tmpfs.txt
ubifs.txt
udf.txt udf: Remove never implemented mount options 2018-02-27 10:25:33 +01:00
ufs.txt
vfat.txt Documentation/filesystems/vfat.txt: fix a remark that implies UCS2 2017-12-21 13:39:28 -07:00
vfs.txt Merge branch 'overlayfs-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs 2017-09-13 09:11:44 -07:00
xfs-delayed-logging-design.txt
xfs-self-describing-metadata.txt
xfs.txt xfs: Change URL for the project in xfs.txt 2018-03-21 09:33:04 -06:00