NFS: Fix sysfs server name memory leak

Free the formatted server index string after it has been duplicated by
kobject_rename().

Fixes: 1c7251187dc0 ("NFS: add superblock sysfs entries")
Reported-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: Benjamin Coddington <bcodding@redhat.com>
Tested-by: Ido Schimmel <idosch@nvidia.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

NFS: Cancel all existing RPC tasks when shutdown

Walk existing RPC tasks and cancel them with -EIO when the client is
shutdown.

Signed-off-by: Benjamin Coddington <bcodding@redhat.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

NFS: add sysfs shutdown knob

Within each nfs_server sysfs tree, add an entry named "shutdown". Writing
1 to this file will set the cl_shutdown bit on the rpc_clnt structs
associated with that mount. If cl_shutdown is set, the task scheduler
immediately returns -EIO for new tasks.

Signed-off-by: Benjamin Coddington <bcodding@redhat.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

NFS: Add sysfs links to sunrpc clients for nfs_clients

For the general and state management nfs_client under each mount, create
symlinks to their respective rpc_client sysfs entries.

Signed-off-by: Benjamin Coddington <bcodding@redhat.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

NFS: add superblock sysfs entries

Create a sysfs directory for each mount that corresponds to the mount's
nfs_server struct. As the mount is being constructed, use the name
"server-n", but rename it to the "MAJOR:MINOR" of the mount after assigning
a device_id. The rename approach allows us to populate the mount's directory
with links to the various rpc_client objects during the mount's
construction. The naming convention (MAJOR:MINOR) can be used to reference
a particular NFS mount's sysfs tree.

Signed-off-by: Benjamin Coddington <bcodding@redhat.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

NFS: Make all of /sys/fs/nfs network-namespace unique

Expand the NFS network-namespaced sysfs from /sys/fs/nfs/net down one level
into /sys/fs/nfs by moving the "net" kobject onto struct
nfs_netns_client and setting it up during network namespace init.

This prepares the way for superblock kobjects within /sys/fs/nfs that will
only be visible to matching network namespaces.

Signed-off-by: Benjamin Coddington <bcodding@redhat.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

NFS: Open-code the nfs_kset kset_create_and_add()

In preparation to make objects below /sys/fs/nfs namespace aware, we need
to define our own kobj_type for the nfs kset so that we can add the
.child_ns_type member in a following patch. No functional change here, only
the unrolling of kset_create_and_add().

Signed-off-by: Benjamin Coddington <bcodding@redhat.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

NFS: rename nfs_client_kobj to nfs_net_kobj

Match the variable names to the sysfs structure.

Signed-off-by: Benjamin Coddington <bcodding@redhat.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

NFS: rename nfs_client_kset to nfs_kset

Be brief and match the subsystem name. There's no need to distinguish this
kset variable from the server.

Signed-off-by: Benjamin Coddington <bcodding@redhat.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

kobject: make kobject_get_ownership() take a constant kobject *

The call, kobject_get_ownership(), does not modify the kobject passed
into it, so make it const. This propagates down into the kobj_type
function callbacks so make the kobject passed into them also const,
ensuring that nothing in the kobject is being changed here.

This helps make it more obvious what calls and callbacks do, and do not,
modify structures passed to them.

Cc: Trond Myklebust <trond.myklebust@hammerspace.com>
Cc: Anna Schumaker <anna@kernel.org>
Cc: Roopa Prabhu <roopa@nvidia.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Paolo Abeni <pabeni@redhat.com>
Cc: Chuck Lever <chuck.lever@oracle.com>
Cc: Jeff Layton <jlayton@kernel.org>
Cc: linux-nfs@vger.kernel.org
Cc: bridge@lists.linux-foundation.org
Cc: netdev@vger.kernel.org
Acked-by: Jakub Kicinski <kuba@kernel.org>
Acked-by: Rafael J. Wysocki <rafael@kernel.org>
Acked-by: Nikolay Aleksandrov <razor@blackwall.org>
Link: https://lore.kernel.org/r/20221121094649.1556002-1-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

fs: nfs: sysfs: use sysfs_emit() to instead of scnprintf()

Follow the advice of the Documentation/filesystems/sysfs.rst and show()
should only use sysfs_emit() or sysfs_emit_at() when formatting the
value to be returned to user space.

Signed-off-by: ye xingchen <ye.xingchen@zte.com.cn>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

Revert "NFSv4: use unique client identifiers in network namespaces"

This reverts commit 50c790a0b69bdc420f00f30bdf348d6c90194c78.

The functionality is believed to be capable of causing regressions in
existing setups, so the author has requested that it be reverted.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

NFSv4: use unique client identifiers in network namespaces

In order to differentiate client state, assign a random uuid to the
uniquifing portion of the client identifier when a network namespace is
created. Containers may still override this value if they wish to maintain
stable client identifiers by writing to /sys/fs/nfs/net/client/identifier,
either by udev rules or other means.

Signed-off-by: Benjamin Coddington <bcodding@redhat.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

NFS: use default_groups in kobj_type

There are currently 2 ways to create a set of sysfs files for a
kobj_type, through the default_attrs field, and the default_groups
field. Move the NFS code to use default_groups field which has been the
preferred way since aa30f47cf666 ("kobject: Add support for default
attribute groups to kobj_type") so that we can soon get rid of the
obsolete default_attrs field.

Cc: Trond Myklebust <trond.myklebust@hammerspace.com>
Cc: Anna Schumaker <anna.schumaker@netapp.com>
Cc: linux-nfs@vger.kernel.org
Link: https://lore.kernel.org/r/20211228144138.389888-1-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

NFS: use default_groups in kobj_type

There are currently 2 ways to create a set of sysfs files for a
kobj_type, through the default_attrs field, and the default_groups
field. Move the NFS code to use default_groups field which has been the
preferred way since aa30f47cf666 ("kobject: Add support for default
attribute groups to kobj_type") so that we can soon get rid of the
obsolete default_attrs field.

Cc: Trond Myklebust <trond.myklebust@hammerspace.com>
Cc: Anna Schumaker <anna.schumaker@netapp.com>
Cc: linux-nfs@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

NFSv4: Fix up RCU annotations for struct nfs_netns_client

The identifier is read as an RCU protected string. Its value may
be changed during the lifetime of the network namespace by writing
a new string into the sysfs pseudofile (at which point, we free the
old string only after a call to synchronize_rcu()).

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

fs: nfs: sysfs: Remove NULL check before kfree

Remove NULL check before kfree, NULL check is taken care
on kfree.

Signed-off-by: Saurav Girepunje <saurav.girepunje@gmail.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

NFS: Add sysfs support for per-container identifier

In order to identify containers to the NFS client, we add a per-net
sysfs attribute that udev can fill with the appropriate identifier.
The identifier could be a unique hostname, but in most cases it
will probably be a persisted uuid.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

NFS: Create a root NFS directory in /sys/fs/nfs

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>