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When there is layout state on a filesystem that is being "unlocked" that
is now revoked, which involves closing the nfsd_file and releasing the
vfs lease.
To avoid races, ->ls_file can now be accessed either:
- under ->fi_lock for the state's sc_file or
- under rcu_read_lock() if nfsd_file_get() is used.
To support this, ->fence_client and nfsd4_cb_layout_fail() now take a
second argument being the nfsd_file.
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
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Revoking state through 'unlock_filesystem' now revokes any delegation
states found. When the stateids are then freed by the client, the
revoked stateids will be cleaned up correctly.
As there is already support for revoking delegations, we build on that
for admin-revoking.
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
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Revoking state through 'unlock_filesystem' now revokes any open states
found. When the stateids are then freed by the client, the revoked
stateids will be cleaned up correctly.
Possibly the related lock states should be revoked too, but a
subsequent patch will do that for all lock state on the superblock.
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
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Revoking state through 'unlock_filesystem' now revokes any lock states
found. When the stateids are then freed by the client, the revoked
stateids will be cleaned up correctly.
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
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For NFSv4.1 and later the client easily discovers if there is any
admin-revoked state and will then find and explicitly free it.
For NFSv4.0 there is no such mechanism. The client can only find that
state is admin-revoked if it tries to use that state, and there is no
way for it to explicitly free the state. So the server must hold on to
the stateid (at least) for an indefinite amount of time. A
RELEASE_LOCKOWNER request might justify forgetting some of these
stateids, as would the whole clients lease lapsing, but these are not
reliable.
This patch takes two approaches.
Whenever a client uses an revoked stateid, that stateid is then
discarded and will not be recognised again. This might confuse a client
which expect to get NFS4ERR_ADMIN_REVOKED consistently once it get it at
all, but should mostly work. Hopefully one error will lead to other
resources being closed (e.g. process exits), which will result in more
stateid being freed when a CLOSE attempt gets NFS4ERR_ADMIN_REVOKED.
Also, any admin-revoked stateids that have been that way for more than
one lease time are periodically revoke.
No actual freeing of state happens in this patch. That will come in
future patches which handle the different sorts of revoked state.
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
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Add "admin-revoked" to the status information for any states that have
been admin-revoked. This can be useful for confirming correct
behaviour.
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
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Change the "show" functions to show some content even if a file cannot
be found. This is the case for admin-revoked state.
This is primarily useful for debugging - to ensure states are being
removed eventually.
So change several seq_printf() to seq_puts(). Some of these are needed
to keep checkpatch happy. Others were done for consistency.
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
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The NFSv4 protocol allows state to be revoked by the admin and has error
codes which allow this to be communicated to the client.
This patch
- introduces a new state-id status SC_STATUS_ADMIN_REVOKED
which can be set on open, lock, or delegation state.
- reports NFS4ERR_ADMIN_REVOKED when these are accessed
- introduces a per-client counter of these states and returns
SEQ4_STATUS_ADMIN_STATE_REVOKED when the counter is not zero.
Decrements this when freeing any admin-revoked state.
- introduces stub code to find all interesting states for a given
superblock so they can be revoked via the 'unlock_filesystem'
file in /proc/fs/nfsd/
No actual states are handled yet.
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
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sc_type identifies the type of a state - open, lock, deleg, layout - and
also the status of a state - closed or revoked.
This is a bit untidy and could get worse when "admin-revoked" states are
added. So clean it up.
With this patch, the type is now all that is stored in sc_type. This is
zero when the state is first added to ->cl_stateids (causing it to be
ignored), and is then set appropriately once it is fully initialised.
It is set under ->cl_lock to ensure atomicity w.r.t lookup. It is now
never cleared.
sc_type is still a bit-set even though at most one bit is set. This allows
lookup functions to be given a bitmap of acceptable types.
sc_type is now an unsigned short rather than char. There is no value in
restricting to just 8 bits.
All the constants now start SC_TYPE_ matching the field in which they
are stored. Keeping the existing names and ensuring clear separation
from non-type flags would have required something like
NFS4_STID_TYPE_CLOSED which is cumbersome. The "NFS4" prefix is
redundant was they only appear in NFS4 code, so remove that and change
STID to SC to match the field.
The status is stored in a separate unsigned short named "sc_status". It
has two flags: SC_STATUS_CLOSED and SC_STATUS_REVOKED.
CLOSED combines NFS4_CLOSED_STID, NFS4_CLOSED_DELEG_STID, and is used
for SC_TYPE_LOCK and SC_TYPE_LAYOUT instead of setting the sc_type to zero.
These flags are only ever set, never cleared.
For deleg stateids they are set under the global state_lock.
For open and lock stateids they are set under ->cl_lock.
For layout stateids they are set under ->ls_lock
nfs4_unhash_stid() has been removed, and we never set sc_type = 0. This
was only used for LOCK and LAYOUT stids and they now use
SC_STATUS_CLOSED.
Also TRACE_DEFINE_NUM() calls for the various STID #define have been
removed because these things are not enums, and so that call is
incorrect.
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
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NFS4_CLOSED_DELEG_STID and NFS4_REVOKED_DELEG_STID are similar in
purpose.
REVOKED is used for NFSv4.1 states which have been revoked because the
lease has expired. CLOSED is used in other cases.
The difference has two practical effects.
1/ REVOKED states are on the ->cl_revoked list
2/ REVOKED states result in nfserr_deleg_revoked from
nfsd4_verify_open_stid() and nfsd4_validate_stateid while
CLOSED states result in nfserr_bad_stid.
Currently a state that is being revoked is first set to "CLOSED" in
unhash_delegation_locked(), then possibly to "REVOKED" in
revoke_delegation(), at which point it is added to the cl_revoked list.
It is possible that a stateid test could see the CLOSED state
which really should be REVOKED, and so return the wrong error code. So
it is safest to remove this window of inconsistency.
With this patch, unhash_delegation_locked() always sets the state
correctly, and revoke_delegation() no longer changes the state.
Also remove a redundant test on minorversion when
NFS4_REVOKED_DELEG_STID is seen - it can only be seen when minorversion
is non-zero.
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
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Code like:
WARN_ON(foo())
looks like an assertion and might not be expected to have any side
effects.
When testing if a function with side-effects fails a construct like
if (foo())
WARN_ON(1);
makes the intent more obvious.
nfsd has several WARN_ON calls where the test has side effects, so it
would be good to change them. These cases don't really need the
WARN_ON. They have never failed in 8 years of usage so let's just
remove the WARN_ON wrapper.
Suggested-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
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The protocol for creating a new state in nfsd is to allocate the state
leaving it largely uninitialised, add that state to the ->cl_stateids
idr so as to reserve a state-id, then complete initialisation of the
state and only set ->sc_type to non-zero once the state is fully
initialised.
If a state is found in the idr with ->sc_type == 0, it is ignored.
The ->cl_lock lock is used to avoid races - it is held while checking
sc_type during lookup, and held when a non-zero value is stored in
->sc_type.
... except... hash_delegation_locked() finalises the initialisation of a
delegation state, but does NOT hold ->cl_lock.
So this patch takes ->cl_lock at the appropriate time w.r.t other locks,
and so ensures there are no races (which are extremely unlikely in any
case).
As ->fi_lock is often taken when ->cl_lock is held, we need to take
->cl_lock first of those two.
Currently ->cl_lock and state_lock are never both taken at the same time.
We need both for this patch so an arbitrary choice is needed concerning
which to take first. As state_lock is more global, it might be more
contended, so take it first.
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
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As we do now support write delegations, this comment is unhelpful and
misleading.
Reported-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
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As far as I can see, setting cb_seq_status in nfsd4_init_cb() is
superfluous because it is set again in nfsd4_cb_prepare().
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Benjamin Coddington <bcodding@redhat.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
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Don't kill the kworker thread, and don't panic while cl_lock is
held. There's no need for scorching the earth here.
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Benjamin Coddington <bcodding@redhat.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
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Convert a code comment into a real assertion.
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Benjamin Coddington <bcodding@redhat.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
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Reviewed-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Benjamin Coddington <bcodding@redhat.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
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Help observe the flow of callback operations.
bc_shutdown() records exactly when the backchannel RPC client is
destroyed and cl_cb_client is replaced with NULL.
Examples include:
nfsd-955 [004] 650.013997: nfsd_cb_queue: addr=192.168.122.6:0 client 65b3c5b8:f541f749 cb=0xffff8881134b02f8 (first try)
kworker/u21:4-497 [004] 650.014050: nfsd_cb_seq_status: task:00000001@00000001 sessionid=65b3c5b8:f541f749:00000001:00000000 tk_status=-107 seq_status=1
kworker/u21:4-497 [004] 650.014051: nfsd_cb_restart: addr=192.168.122.6:0 client 65b3c5b8:f541f749 cb=0xffff88810e39f400 (first try)
kworker/u21:4-497 [004] 650.014066: nfsd_cb_queue: addr=192.168.122.6:0 client 65b3c5b8:f541f749 cb=0xffff88810e39f400 (need restart)
kworker/u16:0-10 [006] 650.065750: nfsd_cb_start: addr=192.168.122.6:0 client 65b3c5b8:f541f749 state=UNKNOWN
kworker/u16:0-10 [006] 650.065752: nfsd_cb_bc_update: addr=192.168.122.6:0 client 65b3c5b8:f541f749 cb=0xffff8881134b02f8 (first try)
kworker/u16:0-10 [006] 650.065754: nfsd_cb_bc_shutdown: addr=192.168.122.6:0 client 65b3c5b8:f541f749 cb=0xffff8881134b02f8 (first try)
kworker/u16:0-10 [006] 650.065810: nfsd_cb_new_state: addr=192.168.122.6:0 client 65b3c5b8:f541f749 state=DOWN
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Benjamin Coddington <bcodding@redhat.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
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Make it clear where backchannel state is updated.
Example trace point output:
kworker/u16:0-10 [006] 2800.080404: nfsd_cb_new_state: addr=192.168.122.6:0 client 65b3c5b8:f541f749 state=UP
nfsd-940 [003] 2800.478368: nfsd_cb_new_state: addr=192.168.122.6:0 client 65b3c5b8:f541f749 state=UNKNOWN
kworker/u16:0-10 [003] 2800.478828: nfsd_cb_new_state: addr=192.168.122.6:0 client 65b3c5b8:f541f749 state=DOWN
kworker/u16:0-10 [005] 2802.039724: nfsd_cb_start: addr=192.168.122.6:0 client 65b3c5b8:f541f749 state=UP
kworker/u16:0-10 [005] 2810.611452: nfsd_cb_start: addr=192.168.122.6:0 client 65b3c5b8:f541f749 state=FAULT
kworker/u16:0-10 [005] 2810.616832: nfsd_cb_start: addr=192.168.122.6:0 client 65b3c5b8:f541f749 state=UNKNOWN
kworker/u16:0-10 [005] 2810.616931: nfsd_cb_start: addr=192.168.122.6:0 client 65b3c5b8:f541f749 state=DOWN
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Benjamin Coddington <bcodding@redhat.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
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Improve observability of backchannel session operation.
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Benjamin Coddington <bcodding@redhat.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
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Add a trace point that records SEQ4_STATUS flags returned in an
NFSv4.1 SEQUENCE response. SEQ4_STATUS flags report backchannel
issues and changes to lease state to clients. Knowing what the
server is reporting to clients is useful for debugging both
configuration and operational issues in real time.
For example, upcoming patches will enable server administrators to
revoke parts of a client's lease; that revocation is indicated to
the client when a subsequent SEQUENCE operation has one or more
SEQ4_STATUS flags that are set.
Sample trace records:
nfsd-927 [006] 615.581821: nfsd_seq4_status: xid=0x095ded07 sessionid=65a032c3:b7845faf:00000001:00000000 status_flags=BACKCHANNEL_FAULT
nfsd-927 [006] 615.588043: nfsd_seq4_status: xid=0x0a5ded07 sessionid=65a032c3:b7845faf:00000001:00000000 status_flags=BACKCHANNEL_FAULT
nfsd-928 [003] 615.588448: nfsd_seq4_status: xid=0x0b5ded07 sessionid=65a032c3:b7845faf:00000001:00000000 status_flags=BACKCHANNEL_FAULT
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Benjamin Coddington <bcodding@redhat.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
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NFSv4.1 clients assume that if they disconnect, that will force the
server to resend pending callback operations once a fresh connection
has been established.
Turns out NFSD has not been resending after reconnect.
Fixes: 7ba6cad6c88f ("nfsd: New helper nfsd4_cb_sequence_done() for processing more cb errors")
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Benjamin Coddington <bcodding@redhat.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
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As part of managing a client disconnect, NFSD closes down and
replaces the backchannel rpc_clnt.
If a callback operation is pending when the backchannel rpc_clnt is
shut down, currently nfsd4_run_cb_work() just discards that
callback. But there are multiple cases to deal with here:
o The client's lease is getting destroyed. Throw the CB away.
o The client disconnected. It might be forcing a retransmit of
CB operations, or it could have disconnected for other reasons.
Reschedule the CB so it is retransmitted when the client
reconnects.
Since callback operations can now be rescheduled, ensure that
cb_ops->prepare can be called only once by moving the
cb_ops->prepare paragraph down to just before the rpc_call_async()
call.
Fixes: 2bbfed98a4d8 ("nfsd: Fix races between nfsd4_cb_release() and nfsd4_shutdown_callback()")
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Benjamin Coddington <bcodding@redhat.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
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Normally, NFSv4 callback operations are supposed to be sent to the
client as soon as they are queued up.
In a moment, I will introduce a recovery path where the server has
to wait for the client to reconnect. We don't want a hard busy wait
here -- the callback should be requeued to try again in several
milliseconds.
For now, convert nfsd4_callback from struct work_struct to struct
delayed_work, and queue with a zero delay argument. This should
avoid behavior changes for current operation.
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Benjamin Coddington <bcodding@redhat.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
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I noticed that once an NFSv4.1 callback operation gets a
NFS4ERR_DELAY status on CB_SEQUENCE and then the connection is lost,
the callback client loops, resending it indefinitely.
The switch arm in nfsd4_cb_sequence_done() that handles
NFS4ERR_DELAY uses rpc_restart_call() to rearm the RPC state machine
for the retransmit, but that path does not call the rpc_prepare_call
callback again. Thus cb_seq_status is set to -10008 by the first
NFS4ERR_DELAY result, but is never set back to 1 for the retransmits.
nfsd4_cb_sequence_done() thinks it's getting nothing but a
long series of CB_SEQUENCE NFS4ERR_DELAY replies.
Fixes: 7ba6cad6c88f ("nfsd: New helper nfsd4_cb_sequence_done() for processing more cb errors")
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Benjamin Coddington <bcodding@redhat.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
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The final bit of stats that is global is the rpc svc_stat. Move this
into the nfsd_net struct and use that everywhere instead of the global
struct. Remove the unused global struct.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
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This is the last global stat, take it out of the nfsd_stats struct and
make it a global part of nfsd, report it the same as always.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
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We have a global set of counters that we modify for all of the nfsd
operations, but now that we're exposing these stats across all network
namespaces we need to make the stats also be per-network namespace. We
already have some caching stats that are per-network namespace, so move
these definitions into the same counter and then adjust all the helpers
and users of these stats to provide the appropriate nfsd_net struct so
that the stats are maintained for the per-network namespace objects.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
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We are running nfsd servers inside of containers with their own network
namespace, and we want to monitor these services using the stats found
in /proc. However these are not exposed in the proc inside of the
container, so we have to bind mount the host /proc into our containers
to get at this information.
Separate out the stat counters init and the proc registration, and move
the proc registration into the pernet operations entry and exit points
so that these stats can be exposed inside of network namespaces.
This is an intermediate step, this just exposes the global counters in
the network namespace. Subsequent patches will move these counters into
the per-network namespace container.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
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We're going to merge the stats all into per network namespace in
subsequent patches, rename these nn counters to be consistent with the
rest of the stats.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
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Now that this isn't used anywhere, remove it.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
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Since only one service actually reports the rpc stats there's not much
of a reason to have a pointer to it in the svc_program struct. Adjust
the svc_create_pooled function to take the sv_stats as an argument and
pass the struct through there as desired instead of getting it from the
svc_program->pg_stats.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
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A lot of places are setting a blank svc_stats in ->pg_stats and never
utilizing these stats. Remove all of these extra structs as we're not
reporting these stats anywhere.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
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The maxcount is the maximum number of bytes for the LISTXATTRS4resok
result. This includes the cookie and the count for the name array,
thus subtract 12 bytes from the maxcount: 8 (cookie) + 4 (array count)
when filling up the name array.
Fixes: 23e50fe3a5e6 ("nfsd: implement the xattr functions and en/decode logic")
Signed-off-by: Jorge Mora <mora@netapp.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
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If the XDR buffer is not large enough to fit all attributes
and the remaining bytes left in the XDR buffer (xdrleft) is
equal to the number of bytes for the current attribute, then
the loop will prematurely exit without setting eof to FALSE.
Also in this case, adding the eof flag to the buffer will
make the reply 4 bytes larger than lsxa_maxcount.
Need to check if there are enough bytes to fit not only the
next attribute name but also the eof as well.
Fixes: 23e50fe3a5e6 ("nfsd: implement the xattr functions and en/decode logic")
Signed-off-by: Jorge Mora <mora@netapp.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
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Function nfsd4_listxattr_validate_cookie() expects the cookie
as an offset to the list thus it needs to be encoded in big-endian.
Fixes: 23e50fe3a5e6 ("nfsd: implement the xattr functions and en/decode logic")
Signed-off-by: Jorge Mora <mora@netapp.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
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If LISTXATTRS is sent with a correct cookie but a small maxcount,
this could lead function nfsd4_listxattr_validate_cookie to
return NFS4ERR_BAD_COOKIE. If maxcount = 20, then second check
on function gives RHS = 3 thus any cookie larger than 3 returns
NFS4ERR_BAD_COOKIE.
There is no need to validate the cookie on the return XDR buffer
since attribute referenced by cookie will be the first in the
return buffer.
Fixes: 23e50fe3a5e6 ("nfsd: implement the xattr functions and en/decode logic")
Signed-off-by: Jorge Mora <mora@netapp.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
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Calling fput() directly or though filp_close() from a kernel thread like
nfsd causes the final __fput() (if necessary) to be called from a
workqueue. This means that nfsd is not forced to wait for any work to
complete. If the ->release or ->destroy_inode function is slow for any
reason, this can result in nfsd closing files more quickly than the
workqueue can complete the close and the queue of pending closes can
grow without bounces (30 million has been seen at one customer site,
though this was in part due to a slowness in xfs which has since been
fixed).
nfsd does not need this. It is quite appropriate and safe for nfsd to
do its own close work. There is no reason that close should ever wait
for nfsd, so no deadlock can occur.
It should be safe and sensible to change all fput() calls to
__fput_sync(). However in the interests of caution this patch only
changes two - the two that can be most directly affected by client
behaviour and could occur at high frequency.
- the fput() implicitly in flip_close() is changed to __fput_sync()
by calling get_file() first to ensure filp_close() doesn't do
the final fput() itself. If is where files opened for IO are closed.
- the fput() in nfsd_read() is also changed. This is where directories
opened for readdir are closed.
This ensure that minimal fput work is queued to the workqueue.
This removes the need for the flush_delayed_fput() call in
nfsd_file_close_inode_sync()
Signed-off-by: NeilBrown <neilb@suse.de>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
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The work of closing a file can have non-trivial cost. Doing it in a
separate work queue thread means that cost isn't imposed on the nfsd
threads and an imbalance can be created. This can result in files being
queued for the work queue more quickly that the work queue can process
them, resulting in unbounded growth of the queue and memory exhaustion.
To avoid this work imbalance that exhausts memory, this patch moves all
closing of files into the nfsd threads. This means that when the work
imposes a cost, that cost appears where it would be expected - in the
work of the nfsd thread. A subsequent patch will ensure the final
__fput() is called in the same (nfsd) thread which calls filp_close().
Files opened for NFSv3 are never explicitly closed by the client and are
kept open by the server in the "filecache", which responds to memory
pressure, is garbage collected even when there is no pressure, and
sometimes closes files when there is particular need such as for rename.
These files currently have filp_close() called in a dedicated work
queue, so their __fput() can have no effect on nfsd threads.
This patch discards the work queue and instead has each nfsd thread call
flip_close() on as many as 8 files from the filecache each time it acts
on a client request (or finds there are no pending client requests). If
there are more to be closed, more threads are woken. This spreads the
work of __fput() over multiple threads and imposes any cost on those
threads.
The number 8 is somewhat arbitrary. It needs to be greater than 1 to
ensure that files are closed more quickly than they can be added to the
cache. It needs to be small enough to limit the per-request delays that
will be imposed on clients when all threads are busy closing files.
Signed-off-by: NeilBrown <neilb@suse.de>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
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Move hardcoded IMA function calls (not appraisal-specific functions) from
various places in the kernel to the LSM infrastructure, by introducing a
new LSM named 'ima' (at the end of the LSM list and always enabled like
'integrity').
Having IMA before EVM in the Makefile is sufficient to preserve the
relative order of the new 'ima' LSM in respect to the upcoming 'evm' LSM,
and thus the order of IMA and EVM function calls as when they were
hardcoded.
Make moved functions as static (except ima_post_key_create_or_update(),
which is not in ima_main.c), and register them as implementation of the
respective hooks in the new function init_ima_lsm().
Select CONFIG_SECURITY_PATH, to ensure that the path-based LSM hook
path_post_mknod is always available and ima_post_path_mknod() is always
executed to mark files as new, as before the move.
A slight difference is that IMA and EVM functions registered for the
inode_post_setattr, inode_post_removexattr, path_post_mknod,
inode_post_create_tmpfile, inode_post_set_acl and inode_post_remove_acl
won't be executed for private inodes. Since those inodes are supposed to be
fs-internal, they should not be of interest to IMA or EVM. The S_PRIVATE
flag is used for anonymous inodes, hugetlbfs, reiserfs xattrs, XFS scrub
and kernel-internal tmpfs files.
Conditionally register ima_post_key_create_or_update() if
CONFIG_IMA_MEASURE_ASYMMETRIC_KEYS is enabled. Also, conditionally register
ima_kernel_module_request() if CONFIG_INTEGRITY_ASYMMETRIC_KEYS is enabled.
Finally, add the LSM_ID_IMA case in lsm_list_modules_test.c.
Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
Acked-by: Chuck Lever <chuck.lever@oracle.com>
Acked-by: Casey Schaufler <casey@schaufler-ca.com>
Acked-by: Christian Brauner <brauner@kernel.org>
Reviewed-by: Stefan Berger <stefanb@linux.ibm.com>
Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
Acked-by: Mimi Zohar <zohar@linux.ibm.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
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In preparation to move IMA and EVM to the LSM infrastructure, introduce the
file_post_open hook. Also, export security_file_post_open() for NFS.
Based on policy, IMA calculates the digest of the file content and
extends the TPM with the digest, verifies the file's integrity based on
the digest, and/or includes the file digest in the audit log.
LSMs could similarly take action depending on the file content and the
access mask requested with open().
The new hook returns a value and can cause the open to be aborted.
Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
Reviewed-by: Stefan Berger <stefanb@linux.ibm.com>
Acked-by: Casey Schaufler <casey@schaufler-ca.com>
Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
Acked-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Paul Moore <paul@paul-moore.com>
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git://git.kernel.org/pub/scm/linux/kernel/git/cel/linux
Pull nfsd fix from Chuck Lever:
- Address a deadlock regression in RELEASE_LOCKOWNER
* tag 'nfsd-6.8-3' of git://git.kernel.org/pub/scm/linux/kernel/git/cel/linux:
nfsd: don't take fi_lock in nfsd_break_deleg_cb()
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A recent change to check_for_locks() changed it to take ->flc_lock while
holding ->fi_lock. This creates a lock inversion (reported by lockdep)
because there is a case where ->fi_lock is taken while holding
->flc_lock.
->flc_lock is held across ->fl_lmops callbacks, and
nfsd_break_deleg_cb() is one of those and does take ->fi_lock. However
it doesn't need to.
Prior to v4.17-rc1~110^2~22 ("nfsd: create a separate lease for each
delegation") nfsd_break_deleg_cb() would walk the ->fi_delegations list
and so needed the lock. Since then it doesn't walk the list and doesn't
need the lock.
Two actions are performed under the lock. One is to call
nfsd_break_one_deleg which calls nfsd4_run_cb(). These doesn't act on
the nfs4_file at all, so don't need the lock.
The other is to set ->fi_had_conflict which is in the nfs4_file.
This field is only ever set here (except when initialised to false)
so there is no possible problem will multiple threads racing when
setting it.
The field is tested twice in nfs4_set_delegation(). The first test does
not hold a lock and is documented as an opportunistic optimisation, so
it doesn't impose any need to hold ->fi_lock while setting
->fi_had_conflict.
The second test in nfs4_set_delegation() *is* make under ->fi_lock, so
removing the locking when ->fi_had_conflict is set could make a change.
The change could only be interesting if ->fi_had_conflict tested as
false even though nfsd_break_one_deleg() ran before ->fi_lock was
unlocked. i.e. while hash_delegation_locked() was running.
As hash_delegation_lock() doesn't interact in any way with nfs4_run_cb()
there can be no importance to this interaction.
So this patch removes the locking from nfsd_break_one_deleg() and moves
the final test on ->fi_had_conflict out of the locked region to make it
clear that locking isn't important to the test. It is still tested
*after* vfs_setlease() has succeeded. This might be significant and as
vfs_setlease() takes ->flc_lock, and nfsd_break_one_deleg() is called
under ->flc_lock this "after" is a true ordering provided by a spinlock.
Fixes: edcf9725150e ("nfsd: fix RELEASE_LOCKOWNER")
Signed-off-by: NeilBrown <neilb@suse.de>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
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Zdenek reported seeing some AVC denials due to nfsd trying to set
delegations:
type=AVC msg=audit(09.11.2023 09:03:46.411:496) : avc: denied { lease } for pid=5127 comm=rpc.nfsd capability=lease scontext=system_u:system_r:nfsd_t:s0 tcontext=system_u:system_r:nfsd_t:s0 tclass=capability permissive=0
When setting delegations on behalf of nfsd, we don't want to do all of
the normal capabilty and LSM checks. nfsd is a kernel thread and runs
with CAP_LEASE set, so the uid checks end up being a no-op in most cases
anyway.
Some nfsd functions can end up running in normal process context when
tearing down the server. At that point, the CAP_LEASE check can fail and
cause the client to not tear down delegations when expected.
Also, the way the per-fs ->setlease handlers work today is a little
convoluted. The non-trivial ones are wrappers around generic_setlease,
so when they fail due to permission problems they usually they end up
doing a little extra work only to determine that they can't set the
lease anyway. It would be more efficient to do those checks earlier.
Transplant the permission checking from generic_setlease to
vfs_setlease, which will make the permission checking happen earlier on
filesystems that have a ->setlease operation. Add a new kernel_setlease
function that bypasses these checks, and switch nfsd to use that instead
of vfs_setlease.
There is one behavioral change here: prior this patch the
setlease_notifier would fire even if the lease attempt was going to fail
the security checks later. With this change, it doesn't fire until the
caller has passed them. I think this is a desirable change overall. nfsd
is the only user of the setlease_notifier and it doesn't benefit from
being notified about failed attempts.
Cc: Ondrej Mosnáček <omosnacek@gmail.com>
Reported-by: Zdenek Pytela <zpytela@redhat.com>
Closes: https://bugzilla.redhat.com/show_bug.cgi?id=2248830
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Link: https://lore.kernel.org/r/20240205-bz2248830-v1-1-d0ec0daecba1@kernel.org
Acked-by: Tom Talpey <tom@talpey.com>
Reviewed-by: NeilBrown <neilb@suse.de>
Signed-off-by: Christian Brauner <brauner@kernel.org>
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Add a new struct file_lease and move the lease-specific fields from
struct file_lock to it. Convert the appropriate API calls to take
struct file_lease instead, and convert the callers to use them.
There is zero overlap between the lock manager operations for file
locks and the ones for file leases, so split the lease-related
operations off into a new lease_manager_operations struct.
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Link: https://lore.kernel.org/r/20240131-flsplit-v3-47-c6129007ee8d@kernel.org
Reviewed-by: NeilBrown <neilb@suse.de>
Signed-off-by: Christian Brauner <brauner@kernel.org>
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Most of the existing APIs have remained the same, but subsystems that
access file_lock fields directly need to reach into struct
file_lock_core now.
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Link: https://lore.kernel.org/r/20240131-flsplit-v3-42-c6129007ee8d@kernel.org
Reviewed-by: NeilBrown <neilb@suse.de>
Signed-off-by: Christian Brauner <brauner@kernel.org>
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In a future patch, we're going to split file leases into their own
structure. Since a lot of the underlying machinery uses the same fields
move those into a new file_lock_core, and embed that inside struct
file_lock.
For now, add some macros to ensure that we can continue to build while
the conversion is in progress.
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Link: https://lore.kernel.org/r/20240131-flsplit-v3-17-c6129007ee8d@kernel.org
Reviewed-by: NeilBrown <neilb@suse.de>
Signed-off-by: Christian Brauner <brauner@kernel.org>
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Convert to using the new file locking helper functions. Also, in later
patches we're going to introduce some macros with names that clash with
the variable names in nfsd4_lock. Rename them.
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Link: https://lore.kernel.org/r/20240131-flsplit-v3-12-c6129007ee8d@kernel.org
Reviewed-by: NeilBrown <neilb@suse.de>
Signed-off-by: Christian Brauner <brauner@kernel.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/cel/linux
Pull nfsd fixes from Chuck Lever:
- Fix in-kernel RPC UDP transport
- Fix NFSv4.0 RELEASE_LOCKOWNER
* tag 'nfsd-6.8-1' of git://git.kernel.org/pub/scm/linux/kernel/git/cel/linux:
nfsd: fix RELEASE_LOCKOWNER
SUNRPC: use request size to initialize bio_vec in svc_udp_sendto()
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The test on so_count in nfsd4_release_lockowner() is nonsense and
harmful. Revert to using check_for_locks(), changing that to not sleep.
First: harmful.
As is documented in the kdoc comment for nfsd4_release_lockowner(), the
test on so_count can transiently return a false positive resulting in a
return of NFS4ERR_LOCKS_HELD when in fact no locks are held. This is
clearly a protocol violation and with the Linux NFS client it can cause
incorrect behaviour.
If RELEASE_LOCKOWNER is sent while some other thread is still
processing a LOCK request which failed because, at the time that request
was received, the given owner held a conflicting lock, then the nfsd
thread processing that LOCK request can hold a reference (conflock) to
the lock owner that causes nfsd4_release_lockowner() to return an
incorrect error.
The Linux NFS client ignores that NFS4ERR_LOCKS_HELD error because it
never sends NFS4_RELEASE_LOCKOWNER without first releasing any locks, so
it knows that the error is impossible. It assumes the lock owner was in
fact released so it feels free to use the same lock owner identifier in
some later locking request.
When it does reuse a lock owner identifier for which a previous RELEASE
failed, it will naturally use a lock_seqid of zero. However the server,
which didn't release the lock owner, will expect a larger lock_seqid and
so will respond with NFS4ERR_BAD_SEQID.
So clearly it is harmful to allow a false positive, which testing
so_count allows.
The test is nonsense because ... well... it doesn't mean anything.
so_count is the sum of three different counts.
1/ the set of states listed on so_stateids
2/ the set of active vfs locks owned by any of those states
3/ various transient counts such as for conflicting locks.
When it is tested against '2' it is clear that one of these is the
transient reference obtained by find_lockowner_str_locked(). It is not
clear what the other one is expected to be.
In practice, the count is often 2 because there is precisely one state
on so_stateids. If there were more, this would fail.
In my testing I see two circumstances when RELEASE_LOCKOWNER is called.
In one case, CLOSE is called before RELEASE_LOCKOWNER. That results in
all the lock states being removed, and so the lockowner being discarded
(it is removed when there are no more references which usually happens
when the lock state is discarded). When nfsd4_release_lockowner() finds
that the lock owner doesn't exist, it returns success.
The other case shows an so_count of '2' and precisely one state listed
in so_stateid. It appears that the Linux client uses a separate lock
owner for each file resulting in one lock state per lock owner, so this
test on '2' is safe. For another client it might not be safe.
So this patch changes check_for_locks() to use the (newish)
find_any_file_locked() so that it doesn't take a reference on the
nfs4_file and so never calls nfsd_file_put(), and so never sleeps. With
this check is it safe to restore the use of check_for_locks() rather
than testing so_count against the mysterious '2'.
Fixes: ce3c4ad7f4ce ("NFSD: Fix possible sleep during nfsd4_release_lockowner()")
Signed-off-by: NeilBrown <neilb@suse.de>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Cc: stable@vger.kernel.org # v6.2+
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
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