linux-toradex.git/Documentation/filesystems/nfs, branch v4.19-rc4 Linux kernel for Apalis and Colibri modules ipconfig: Write NTP server IPs to /proc/net/ipconfig/ntp_servers 2018-04-24T17:40:42+00:00 Chris Novakovic chris@chrisn.me.uk 2018-04-24T02:56:39+00:00 c04d2cb2009f87cba7431c4ed3d85a602f71658e 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> 
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>
ipconfig: Document /proc/net/pnp 2018-04-24T17:40:41+00:00 Chris Novakovic chris@chrisn.me.uk 2018-04-24T02:56:36+00:00 8b0b37c5644e1c0e0feac5bbf673337cefa3efb2 Fully document the format used by the /proc/net/pnp file written by ipconfig, explain where its values originate from, and clarify that the tertiary name server IP and DNS domain name are only written to the file when autoconfiguration is used. Signed-off-by: Chris Novakovic <chris@chrisn.me.uk> Signed-off-by: David S. Miller <davem@davemloft.net> 
Fully document the format used by the /proc/net/pnp file written by
ipconfig, explain where its values originate from, and clarify that the
tertiary name server IP and DNS domain name are only written to the file
when autoconfiguration is used.

Signed-off-by: Chris Novakovic <chris@chrisn.me.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
ipconfig: Document setting of NIS domain name 2018-04-24T17:40:41+00:00 Chris Novakovic chris@chrisn.me.uk 2018-04-24T02:56:32+00:00 660de409e25ba5bf34e8fdf2e13b69f1a7bd7213 ic_do_bootp_ext() is responsible for parsing the "ip=" and "nfsaddrs=" kernel parameters. If a "." character is found in parameter 4 (the client's hostname), everything before the first "." is used as the hostname, and everything after it is used as the NIS domain name (but not necessarily the DNS domain name). Document this behaviour in Documentation/filesystems/nfs/nfsroot.txt, as it is not made explicit. Signed-off-by: Chris Novakovic <chris@chrisn.me.uk> Signed-off-by: David S. Miller <davem@davemloft.net> 
ic_do_bootp_ext() is responsible for parsing the "ip=" and "nfsaddrs="
kernel parameters. If a "." character is found in parameter 4 (the
client's hostname), everything before the first "." is used as the
hostname, and everything after it is used as the NIS domain name (but
not necessarily the DNS domain name).

Document this behaviour in Documentation/filesystems/nfs/nfsroot.txt,
as it is not made explicit.

Signed-off-by: Chris Novakovic <chris@chrisn.me.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
VFS: don't keep disconnected dentries on d_anon 2017-12-26T01:22:07+00:00 NeilBrown neilb@suse.com 2017-12-20T22:45:40+00:00 f1ee616214cb22410e939d963bbb2349c2570f02 The original purpose of the per-superblock d_anon list was to keep disconnected dentries in the cache between consecutive requests to the NFS server. Dentries can be disconnected if a client holds a file open and repeatedly performs IO on it, and if the server drops the dentry, whether due to memory pressure, server restart, or "echo 3 > /proc/sys/vm/drop_caches". This purpose was thwarted by commit 75a6f82a0d10 ("freeing unlinked file indefinitely delayed") which caused disconnected dentries to be freed as soon as their refcount reached zero. This means that, when a dentry being used by nfsd gets disconnected, a new one needs to be allocated for every request (unless requests overlap). As the dentry has no name, no parent, and no children, there is little of value to cache. As small memory allocations are typically fast (from per-cpu free lists) this likely has little cost. This means that the original purpose of s_anon is no longer relevant: there is no longer any need to keep disconnected dentries on a list so they appear to be hashed. However, s_anon now has a new use. When you mount an NFS filesystem, the dentry stored in s_root is just a placebo. The "real" root dentry is allocated using d_obtain_root() and so it kept on the s_anon list. I don't know the reason for this, but suspect it related to NFSv4 where a mount of "server:/some/path" require NFS to look up the root filehandle on the server, then walk down "/some" and "/path" to get the filehandle to mount. Whatever the reason, NFS depends on the s_anon list and on shrink_dcache_for_umount() pruning all dentries on this list. So we cannot simply remove s_anon. We could just leave the code unchanged, but apart from that being potentially confusing, the (unfair) bit-spin-lock which protects s_anon can become a bottle neck when lots of disconnected dentries are being created. So this patch renames s_anon to s_roots, and stops storing disconnected dentries on the list. Only dentries obtained with d_obtain_root() are now stored on this list. There are many fewer of these (only NFS and NILFS2 use the call, and only during filesystem mount) so contention on the bit-lock will not be a problem. Possibly an alternate solution should be found for NFS and NILFS2, but that would require understanding their needs first. Signed-off-by: NeilBrown <neilb@suse.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> 
The original purpose of the per-superblock d_anon list was to
keep disconnected dentries in the cache between consecutive
requests to the NFS server.  Dentries can be disconnected if
a client holds a file open and repeatedly performs IO on it,
and if the server drops the dentry, whether due to memory
pressure, server restart, or "echo 3 > /proc/sys/vm/drop_caches".

This purpose was thwarted by commit 75a6f82a0d10 ("freeing unlinked
file indefinitely delayed") which caused disconnected dentries
to be freed as soon as their refcount reached zero.

This means that, when a dentry being used by nfsd gets disconnected, a
new one needs to be allocated for every request (unless requests
overlap).  As the dentry has no name, no parent, and no children,
there is little of value to cache.  As small memory allocations are
typically fast (from per-cpu free lists) this likely has little cost.

This means that the original purpose of s_anon is no longer relevant:
there is no longer any need to keep disconnected dentries on a list so
they appear to be hashed.

However, s_anon now has a new use.  When you mount an NFS filesystem,
the dentry stored in s_root is just a placebo.  The "real" root dentry
is allocated using d_obtain_root() and so it kept on the s_anon list.
I don't know the reason for this, but suspect it related to NFSv4
where a mount of "server:/some/path" require NFS to look up the root
filehandle on the server, then walk down "/some" and "/path" to get
the filehandle to mount.

Whatever the reason, NFS depends on the s_anon list and on
shrink_dcache_for_umount() pruning all dentries on this list.  So we
cannot simply remove s_anon.

We could just leave the code unchanged, but apart from that being
potentially confusing, the (unfair) bit-spin-lock which protects
s_anon can become a bottle neck when lots of disconnected dentries are
being created.

So this patch renames s_anon to s_roots, and stops storing
disconnected dentries on the list.  Only dentries obtained with
d_obtain_root() are now stored on this list.  There are many fewer of
these (only NFS and NILFS2 use the call, and only during filesystem
mount) so contention on the bit-lock will not be a problem.

Possibly an alternate solution should be found for NFS and NILFS2, but
that would require understanding their needs first.

Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
doc: ReSTify keys-request-key.txt 2017-05-18T16:33:51+00:00 Kees Cook keescook@chromium.org 2017-05-13T11:51:52+00:00 3db38ed76890565772fcca3279cc8d454ea6176b Adjusts for ReST markup and moves under keys security devel index. Cc: David Howells <dhowells@redhat.com> Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: Jonathan Corbet <corbet@lwn.net> 
Adjusts for ReST markup and moves under keys security devel index.

Cc: David Howells <dhowells@redhat.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Merge tag 'nfs-for-4.12-1' of git://git.linux-nfs.org/projects/trondmy/linux-nfs 2017-05-10T20:03:38+00:00 Linus Torvalds torvalds@linux-foundation.org 2017-05-10T20:03:38+00:00 73ccb023a2f25b72c4b95499ca24760588014614 Pull NFS client updates from Trond Myklebust: "Highlights include: Stable bugfixes: - Fix use after free in write error path - Use GFP_NOIO for two allocations in writeback - Fix a hang in OPEN related to server reboot - Check the result of nfs4_pnfs_ds_connect - Fix an rcu lock leak Features: - Removal of the unmaintained and unused OSD pNFS layout - Cleanup and removal of lots of unnecessary dprintk()s - Cleanup and removal of some memory failure paths now that GFP_NOFS is guaranteed to never fail. - Remove the v3-only data server limitation on pNFS/flexfiles Bugfixes: - RPC/RDMA connection handling bugfixes - Copy offload: fixes to ensure the copied data is COMMITed to disk. - Readdir: switch back to using the ->iterate VFS interface - File locking fixes from Ben Coddington - Various use-after-free and deadlock issues in pNFS - Write path bugfixes" * tag 'nfs-for-4.12-1' of git://git.linux-nfs.org/projects/trondmy/linux-nfs: (89 commits) pNFS/flexfiles: Always attempt to call layoutstats when flexfiles is enabled NFSv4.1: Work around a Linux server bug... NFS append COMMIT after synchronous COPY NFSv4: Fix exclusive create attributes encoding NFSv4: Fix an rcu lock leak nfs: use kmap/kunmap directly NFS: always treat the invocation of nfs_getattr as cache hit when noac is on Fix nfs_client refcounting if kmalloc fails in nfs4_proc_exchange_id and nfs4_proc_async_renew NFSv4.1: RECLAIM_COMPLETE must handle NFS4ERR_CONN_NOT_BOUND_TO_SESSION pNFS: Fix NULL dereference in pnfs_generic_alloc_ds_commits pNFS: Fix a typo in pnfs_generic_alloc_ds_commits pNFS: Fix a deadlock when coalescing writes and returning the layout pNFS: Don't clear the layout return info if there are segments to return pNFS: Ensure we commit the layout if it has been invalidated pNFS: Don't send COMMITs to the DSes if the server invalidated our layout pNFS/flexfiles: Fix up the ff_layout_write_pagelist failure path pNFS: Ensure we check layout validity before marking it for return NFS4.1 handle interrupted slot reuse from ERR_DELAY NFSv4: check return value of xdr_inline_decode nfs/filelayout: fix NULL pointer dereference in fl_pnfs_update_layout() ... 
Pull NFS client updates from Trond Myklebust:
 "Highlights include:

  Stable bugfixes:
   - Fix use after free in write error path
   - Use GFP_NOIO for two allocations in writeback
   - Fix a hang in OPEN related to server reboot
   - Check the result of nfs4_pnfs_ds_connect
   - Fix an rcu lock leak

  Features:
   - Removal of the unmaintained and unused OSD pNFS layout
   - Cleanup and removal of lots of unnecessary dprintk()s
   - Cleanup and removal of some memory failure paths now that GFP_NOFS
     is guaranteed to never fail.
   - Remove the v3-only data server limitation on pNFS/flexfiles

  Bugfixes:
   - RPC/RDMA connection handling bugfixes
   - Copy offload: fixes to ensure the copied data is COMMITed to disk.
   - Readdir: switch back to using the ->iterate VFS interface
   - File locking fixes from Ben Coddington
   - Various use-after-free and deadlock issues in pNFS
   - Write path bugfixes"

* tag 'nfs-for-4.12-1' of git://git.linux-nfs.org/projects/trondmy/linux-nfs: (89 commits)
  pNFS/flexfiles: Always attempt to call layoutstats when flexfiles is enabled
  NFSv4.1: Work around a Linux server bug...
  NFS append COMMIT after synchronous COPY
  NFSv4: Fix exclusive create attributes encoding
  NFSv4: Fix an rcu lock leak
  nfs: use kmap/kunmap directly
  NFS: always treat the invocation of nfs_getattr as cache hit when noac is on
  Fix nfs_client refcounting if kmalloc fails in nfs4_proc_exchange_id and nfs4_proc_async_renew
  NFSv4.1: RECLAIM_COMPLETE must handle NFS4ERR_CONN_NOT_BOUND_TO_SESSION
  pNFS: Fix NULL dereference in pnfs_generic_alloc_ds_commits
  pNFS: Fix a typo in pnfs_generic_alloc_ds_commits
  pNFS: Fix a deadlock when coalescing writes and returning the layout
  pNFS: Don't clear the layout return info if there are segments to return
  pNFS: Ensure we commit the layout if it has been invalidated
  pNFS: Don't send COMMITs to the DSes if the server invalidated our layout
  pNFS/flexfiles: Fix up the ff_layout_write_pagelist failure path
  pNFS: Ensure we check layout validity before marking it for return
  NFS4.1 handle interrupted slot reuse from ERR_DELAY
  NFSv4: check return value of xdr_inline_decode
  nfs/filelayout: fix NULL pointer dereference in fl_pnfs_update_layout()
  ...
nfs: remove the objlayout driver 2017-04-20T19:51:23+00:00 Christoph Hellwig hch@lst.de 2017-04-12T16:01:08+00:00 6d22323b2e9f95f99aa6f3e93c302f8100277078 The objlayout code has been in the tree, but it's been unmaintained and no server product for it actually ever shipped. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com> 
The objlayout code has been in the tree, but it's been unmaintained and
no server product for it actually ever shipped.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Documentation: Fix dead URLs to ftp.kernel.org 2017-03-29T21:46:06+00:00 SeongJae Park sj38.park@gmail.com 2017-03-27T13:05:34+00:00 3bdadc86dca07c792c01b966575f00cfc25da4a3 As ftp.kernel.org is closed [0], this commit fixes dead URLs in documents to use www.kernel.org instead. [0] https://www.kernel.org/shutting-down-ftp-services.html Signed-off-by: SeongJae Park <sj38.park@gmail.com> Acked-by: Theodore Ts'o <tytso@mit.edu> Acked-by: David S. Miller <davem@davemloft.net> Reviewed-by: Mauro Carvalho Chehab <mchehab@s-opensource.com> Signed-off-by: Jonathan Corbet <corbet@lwn.net> 
As ftp.kernel.org is closed [0], this commit fixes dead URLs in
documents to use www.kernel.org instead.

[0] https://www.kernel.org/shutting-down-ftp-services.html

Signed-off-by: SeongJae Park <sj38.park@gmail.com>
Acked-by: Theodore Ts'o <tytso@mit.edu>
Acked-by: David S. Miller <davem@davemloft.net>
Reviewed-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
docs: fix locations of several documents that got moved 2016-10-24T10:12:35+00:00 Mauro Carvalho Chehab mchehab@s-opensource.com 2016-10-18T12:12:27+00:00 8c27ceff3604b249a9efafbd1bd8b141b79e619d The previous patch renamed several files that are cross-referenced along the Kernel documentation. Adjust the links to point to the right places. Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com> 
The previous patch renamed several files that are cross-referenced
along the Kernel documentation. Adjust the links to point to
the right places.

Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Merge tag 'nfsd-4.6-1' of git://linux-nfs.org/~bfields/linux 2016-03-25T02:50:32+00:00 Linus Torvalds torvalds@linux-foundation.org 2016-03-25T02:50:32+00:00 8b306a2e7c8b23d65682fd70d861e2ba2ae10926 Pull more nfsd updates from Bruce Fields: "Apologies for the previous request, which omitted the top 8 commits from my for-next branch (including the SCSI layout commits). Thanks to Trond for spotting my error!" This actually includes the new layout types, so here's that part of the pull message repeated: "Support for a new pnfs layout type from Christoph Hellwig. The new layout type is a variant of the block layout which uses SCSI features to offer improved fencing and device identification. Note this pull request also includes the client side of SCSI layout, with Trond's permission" * tag 'nfsd-4.6-1' of git://linux-nfs.org/~bfields/linux: nfsd: use short read as well as i_size to set eof nfsd: better layoutupdate bounds-checking nfsd: block and scsi layout drivers need to depend on CONFIG_BLOCK nfsd: add SCSI layout support nfsd: move some blocklayout code nfsd: add a new config option for the block layout driver nfs/blocklayout: add SCSI layout support nfs4.h: add SCSI layout definitions 
Pull more nfsd updates from Bruce Fields:
 "Apologies for the previous request, which omitted the top 8 commits
  from my for-next branch (including the SCSI layout commits).  Thanks
  to Trond for spotting my error!"

This actually includes the new layout types, so here's that part of
the pull message repeated:

 "Support for a new pnfs layout type from Christoph Hellwig.  The new
  layout type is a variant of the block layout which uses SCSI features
  to offer improved fencing and device identification.

  Note this pull request also includes the client side of SCSI layout,
  with Trond's permission"

* tag 'nfsd-4.6-1' of git://linux-nfs.org/~bfields/linux:
  nfsd: use short read as well as i_size to set eof
  nfsd: better layoutupdate bounds-checking
  nfsd: block and scsi layout drivers need to depend on CONFIG_BLOCK
  nfsd: add SCSI layout support
  nfsd: move some blocklayout code
  nfsd: add a new config option for the block layout driver
  nfs/blocklayout: add SCSI layout support
  nfs4.h: add SCSI layout definitions