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linux/fs/nfs/delegation.c
Trond Myklebust fc51b1cf39 NFS: Beware when dereferencing the delegation cred 
When we look up the delegation cred, we are usually doing so in
conjunction with a read of the stateid, and we want to ensure
that the look up is atomic with that read.

Fixes: 57f188e047 ("NFSv4: nfs_update_inplace_delegation() should update delegation cred")
[sfr@canb.auug.org.au: Fixed up borken Fixes: line from Trond :-)]
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2020-04-03 18:26:02 -04:00

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// SPDX-License-Identifier: GPL-2.0-only
/*
* linux/fs/nfs/delegation.c
*
* Copyright (C) 2004 Trond Myklebust
*
* NFS file delegation management
*
*/
#include <linux/completion.h>
#include <linux/kthread.h>
#include <linux/module.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/iversion.h>
#include <linux/nfs4.h>
#include <linux/nfs_fs.h>
#include <linux/nfs_xdr.h>
#include "nfs4_fs.h"
#include "nfs4session.h"
#include "delegation.h"
#include "internal.h"
#include "nfs4trace.h"
#define NFS_DEFAULT_DELEGATION_WATERMARK (5000U)
static atomic_long_t nfs_active_delegations;
static unsigned nfs_delegation_watermark = NFS_DEFAULT_DELEGATION_WATERMARK;
static void __nfs_free_delegation(struct nfs_delegation *delegation)
{
put_cred(delegation->cred);
delegation->cred = NULL;
kfree_rcu(delegation, rcu);
}
static void nfs_mark_delegation_revoked(struct nfs_delegation *delegation)
{
if (!test_and_set_bit(NFS_DELEGATION_REVOKED, &delegation->flags)) {
delegation->stateid.type = NFS4_INVALID_STATEID_TYPE;
atomic_long_dec(&nfs_active_delegations);
if (!test_bit(NFS_DELEGATION_RETURNING, &delegation->flags))
nfs_clear_verifier_delegated(delegation->inode);
}
}
static struct nfs_delegation *nfs_get_delegation(struct nfs_delegation *delegation)
{
refcount_inc(&delegation->refcount);
return delegation;
}
static void nfs_put_delegation(struct nfs_delegation *delegation)
{
if (refcount_dec_and_test(&delegation->refcount))
__nfs_free_delegation(delegation);
}
static void nfs_free_delegation(struct nfs_delegation *delegation)
{
nfs_mark_delegation_revoked(delegation);
nfs_put_delegation(delegation);
}
/**
* nfs_mark_delegation_referenced - set delegation's REFERENCED flag
* @delegation: delegation to process
*
*/
void nfs_mark_delegation_referenced(struct nfs_delegation *delegation)
{
set_bit(NFS_DELEGATION_REFERENCED, &delegation->flags);
}
static bool
nfs4_is_valid_delegation(const struct nfs_delegation *delegation,
fmode_t flags)
{
if (delegation != NULL && (delegation->type & flags) == flags &&
!test_bit(NFS_DELEGATION_REVOKED, &delegation->flags) &&
!test_bit(NFS_DELEGATION_RETURNING, &delegation->flags))
return true;
return false;
}
struct nfs_delegation *nfs4_get_valid_delegation(const struct inode *inode)
{
struct nfs_delegation *delegation;
delegation = rcu_dereference(NFS_I(inode)->delegation);
if (nfs4_is_valid_delegation(delegation, 0))
return delegation;
return NULL;
}
static int
nfs4_do_check_delegation(struct inode *inode, fmode_t flags, bool mark)
{
struct nfs_delegation *delegation;
int ret = 0;
flags &= FMODE_READ|FMODE_WRITE;
rcu_read_lock();
delegation = rcu_dereference(NFS_I(inode)->delegation);
if (nfs4_is_valid_delegation(delegation, flags)) {
if (mark)
nfs_mark_delegation_referenced(delegation);
ret = 1;
}
rcu_read_unlock();
return ret;
}
/**
* nfs_have_delegation - check if inode has a delegation, mark it
* NFS_DELEGATION_REFERENCED if there is one.
* @inode: inode to check
* @flags: delegation types to check for
*
* Returns one if inode has the indicated delegation, otherwise zero.
*/
int nfs4_have_delegation(struct inode *inode, fmode_t flags)
{
return nfs4_do_check_delegation(inode, flags, true);
}
/*
* nfs4_check_delegation - check if inode has a delegation, do not mark
* NFS_DELEGATION_REFERENCED if it has one.
*/
int nfs4_check_delegation(struct inode *inode, fmode_t flags)
{
return nfs4_do_check_delegation(inode, flags, false);
}
static int nfs_delegation_claim_locks(struct nfs4_state *state, const nfs4_stateid *stateid)
{
struct inode *inode = state->inode;
struct file_lock *fl;
struct file_lock_context *flctx = inode->i_flctx;
struct list_head *list;
int status = 0;
if (flctx == NULL)
goto out;
list = &flctx->flc_posix;
spin_lock(&flctx->flc_lock);
restart:
list_for_each_entry(fl, list, fl_list) {
if (nfs_file_open_context(fl->fl_file)->state != state)
continue;
spin_unlock(&flctx->flc_lock);
status = nfs4_lock_delegation_recall(fl, state, stateid);
if (status < 0)
goto out;
spin_lock(&flctx->flc_lock);
}
if (list == &flctx->flc_posix) {
list = &flctx->flc_flock;
goto restart;
}
spin_unlock(&flctx->flc_lock);
out:
return status;
}
static int nfs_delegation_claim_opens(struct inode *inode,
const nfs4_stateid *stateid, fmode_t type)
{
struct nfs_inode *nfsi = NFS_I(inode);
struct nfs_open_context *ctx;
struct nfs4_state_owner *sp;
struct nfs4_state *state;
unsigned int seq;
int err;
again:
rcu_read_lock();
list_for_each_entry_rcu(ctx, &nfsi->open_files, list) {
state = ctx->state;
if (state == NULL)
continue;
if (!test_bit(NFS_DELEGATED_STATE, &state->flags))
continue;
if (!nfs4_valid_open_stateid(state))
continue;
if (!nfs4_stateid_match(&state->stateid, stateid))
continue;
if (!get_nfs_open_context(ctx))
continue;
rcu_read_unlock();
sp = state->owner;
/* Block nfs4_proc_unlck */
mutex_lock(&sp->so_delegreturn_mutex);
seq = raw_seqcount_begin(&sp->so_reclaim_seqcount);
err = nfs4_open_delegation_recall(ctx, state, stateid);
if (!err)
err = nfs_delegation_claim_locks(state, stateid);
if (!err && read_seqcount_retry(&sp->so_reclaim_seqcount, seq))
err = -EAGAIN;
mutex_unlock(&sp->so_delegreturn_mutex);
put_nfs_open_context(ctx);
if (err != 0)
return err;
goto again;
}
rcu_read_unlock();
return 0;
}
/**
* nfs_inode_reclaim_delegation - process a delegation reclaim request
* @inode: inode to process
* @cred: credential to use for request
* @type: delegation type
* @stateid: delegation stateid
* @pagemod_limit: write delegation "space_limit"
*
*/
void nfs_inode_reclaim_delegation(struct inode *inode, const struct cred *cred,
fmode_t type,
const nfs4_stateid *stateid,
unsigned long pagemod_limit)
{
struct nfs_delegation *delegation;
const struct cred *oldcred = NULL;
rcu_read_lock();
delegation = rcu_dereference(NFS_I(inode)->delegation);
if (delegation != NULL) {
spin_lock(&delegation->lock);
if (nfs4_is_valid_delegation(delegation, 0)) {
nfs4_stateid_copy(&delegation->stateid, stateid);
delegation->type = type;
delegation->pagemod_limit = pagemod_limit;
oldcred = delegation->cred;
delegation->cred = get_cred(cred);
clear_bit(NFS_DELEGATION_NEED_RECLAIM,
&delegation->flags);
spin_unlock(&delegation->lock);
rcu_read_unlock();
put_cred(oldcred);
trace_nfs4_reclaim_delegation(inode, type);
return;
}
/* We appear to have raced with a delegation return. */
spin_unlock(&delegation->lock);
}
rcu_read_unlock();
nfs_inode_set_delegation(inode, cred, type, stateid, pagemod_limit);
}
static int nfs_do_return_delegation(struct inode *inode, struct nfs_delegation *delegation, int issync)
{
const struct cred *cred;
int res = 0;
if (!test_bit(NFS_DELEGATION_REVOKED, &delegation->flags)) {
spin_lock(&delegation->lock);
cred = get_cred(delegation->cred);
spin_unlock(&delegation->lock);
res = nfs4_proc_delegreturn(inode, cred,
&delegation->stateid,
issync);
put_cred(cred);
}
return res;
}
static struct inode *nfs_delegation_grab_inode(struct nfs_delegation *delegation)
{
struct inode *inode = NULL;
spin_lock(&delegation->lock);
if (delegation->inode != NULL)
inode = igrab(delegation->inode);
if (!inode)
set_bit(NFS_DELEGATION_INODE_FREEING, &delegation->flags);
spin_unlock(&delegation->lock);
return inode;
}
static struct nfs_delegation *
nfs_start_delegation_return_locked(struct nfs_inode *nfsi)
{
struct nfs_delegation *ret = NULL;
struct nfs_delegation *delegation = rcu_dereference(nfsi->delegation);
if (delegation == NULL)
goto out;
spin_lock(&delegation->lock);
if (!test_and_set_bit(NFS_DELEGATION_RETURNING, &delegation->flags)) {
/* Refcount matched in nfs_end_delegation_return() */
ret = nfs_get_delegation(delegation);
}
spin_unlock(&delegation->lock);
if (ret)
nfs_clear_verifier_delegated(&nfsi->vfs_inode);
out:
return ret;
}
static struct nfs_delegation *
nfs_start_delegation_return(struct nfs_inode *nfsi)
{
struct nfs_delegation *delegation;
rcu_read_lock();
delegation = nfs_start_delegation_return_locked(nfsi);
rcu_read_unlock();
return delegation;
}
static void
nfs_abort_delegation_return(struct nfs_delegation *delegation,
struct nfs_client *clp)
{
spin_lock(&delegation->lock);
clear_bit(NFS_DELEGATION_RETURNING, &delegation->flags);
set_bit(NFS_DELEGATION_RETURN, &delegation->flags);
spin_unlock(&delegation->lock);
set_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state);
}
static struct nfs_delegation *
nfs_detach_delegation_locked(struct nfs_inode *nfsi,
struct nfs_delegation *delegation,
struct nfs_client *clp)
{
struct nfs_delegation *deleg_cur =
rcu_dereference_protected(nfsi->delegation,
lockdep_is_held(&clp->cl_lock));
if (deleg_cur == NULL || delegation != deleg_cur)
return NULL;
spin_lock(&delegation->lock);
if (!delegation->inode) {
spin_unlock(&delegation->lock);
return NULL;
}
list_del_rcu(&delegation->super_list);
delegation->inode = NULL;
rcu_assign_pointer(nfsi->delegation, NULL);
spin_unlock(&delegation->lock);
return delegation;
}
static struct nfs_delegation *nfs_detach_delegation(struct nfs_inode *nfsi,
struct nfs_delegation *delegation,
struct nfs_server *server)
{
struct nfs_client *clp = server->nfs_client;
spin_lock(&clp->cl_lock);
delegation = nfs_detach_delegation_locked(nfsi, delegation, clp);
spin_unlock(&clp->cl_lock);
return delegation;
}
static struct nfs_delegation *
nfs_inode_detach_delegation(struct inode *inode)
{
struct nfs_inode *nfsi = NFS_I(inode);
struct nfs_server *server = NFS_SERVER(inode);
struct nfs_delegation *delegation;
rcu_read_lock();
delegation = rcu_dereference(nfsi->delegation);
if (delegation != NULL)
delegation = nfs_detach_delegation(nfsi, delegation, server);
rcu_read_unlock();
return delegation;
}
static void
nfs_update_delegation_cred(struct nfs_delegation *delegation,
const struct cred *cred)
{
const struct cred *old;
if (cred_fscmp(delegation->cred, cred) != 0) {
old = xchg(&delegation->cred, get_cred(cred));
put_cred(old);
}
}
static void
nfs_update_inplace_delegation(struct nfs_delegation *delegation,
const struct nfs_delegation *update)
{
if (nfs4_stateid_is_newer(&update->stateid, &delegation->stateid)) {
delegation->stateid.seqid = update->stateid.seqid;
smp_wmb();
delegation->type = update->type;
delegation->pagemod_limit = update->pagemod_limit;
if (test_bit(NFS_DELEGATION_REVOKED, &delegation->flags)) {
delegation->change_attr = update->change_attr;
nfs_update_delegation_cred(delegation, update->cred);
/* smp_mb__before_atomic() is implicit due to xchg() */
clear_bit(NFS_DELEGATION_REVOKED, &delegation->flags);
atomic_long_inc(&nfs_active_delegations);
}
}
}
/**
* nfs_inode_set_delegation - set up a delegation on an inode
* @inode: inode to which delegation applies
* @cred: cred to use for subsequent delegation processing
* @type: delegation type
* @stateid: delegation stateid
* @pagemod_limit: write delegation "space_limit"
*
* Returns zero on success, or a negative errno value.
*/
int nfs_inode_set_delegation(struct inode *inode, const struct cred *cred,
fmode_t type,
const nfs4_stateid *stateid,
unsigned long pagemod_limit)
{
struct nfs_server *server = NFS_SERVER(inode);
struct nfs_client *clp = server->nfs_client;
struct nfs_inode *nfsi = NFS_I(inode);
struct nfs_delegation *delegation, *old_delegation;
struct nfs_delegation *freeme = NULL;
int status = 0;
delegation = kmalloc(sizeof(*delegation), GFP_NOFS);
if (delegation == NULL)
return -ENOMEM;
nfs4_stateid_copy(&delegation->stateid, stateid);
refcount_set(&delegation->refcount, 1);
delegation->type = type;
delegation->pagemod_limit = pagemod_limit;
delegation->change_attr = inode_peek_iversion_raw(inode);
delegation->cred = get_cred(cred);
delegation->inode = inode;
delegation->flags = 1<<NFS_DELEGATION_REFERENCED;
spin_lock_init(&delegation->lock);
spin_lock(&clp->cl_lock);
old_delegation = rcu_dereference_protected(nfsi->delegation,
lockdep_is_held(&clp->cl_lock));
if (old_delegation == NULL)
goto add_new;
/* Is this an update of the existing delegation? */
if (nfs4_stateid_match_other(&old_delegation->stateid,
&delegation->stateid)) {
spin_lock(&old_delegation->lock);
nfs_update_inplace_delegation(old_delegation,
delegation);
spin_unlock(&old_delegation->lock);
goto out;
}
if (!test_bit(NFS_DELEGATION_REVOKED, &old_delegation->flags)) {
/*
* Deal with broken servers that hand out two
* delegations for the same file.
* Allow for upgrades to a WRITE delegation, but
* nothing else.
*/
dfprintk(FILE, "%s: server %s handed out "
"a duplicate delegation!\n",
__func__, clp->cl_hostname);
if (delegation->type == old_delegation->type ||
!(delegation->type & FMODE_WRITE)) {
freeme = delegation;
delegation = NULL;
goto out;
}
if (test_and_set_bit(NFS_DELEGATION_RETURNING,
&old_delegation->flags))
goto out;
}
freeme = nfs_detach_delegation_locked(nfsi, old_delegation, clp);
if (freeme == NULL)
goto out;
add_new:
list_add_tail_rcu(&delegation->super_list, &server->delegations);
rcu_assign_pointer(nfsi->delegation, delegation);
delegation = NULL;
atomic_long_inc(&nfs_active_delegations);
trace_nfs4_set_delegation(inode, type);
spin_lock(&inode->i_lock);
if (NFS_I(inode)->cache_validity & (NFS_INO_INVALID_ATTR|NFS_INO_INVALID_ATIME))
NFS_I(inode)->cache_validity |= NFS_INO_REVAL_FORCED;
spin_unlock(&inode->i_lock);
out:
spin_unlock(&clp->cl_lock);
if (delegation != NULL)
__nfs_free_delegation(delegation);
if (freeme != NULL) {
nfs_do_return_delegation(inode, freeme, 0);
nfs_free_delegation(freeme);
}
return status;
}
/*
* Basic procedure for returning a delegation to the server
*/
static int nfs_end_delegation_return(struct inode *inode, struct nfs_delegation *delegation, int issync)
{
struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
int err = 0;
if (delegation == NULL)
return 0;
do {
if (test_bit(NFS_DELEGATION_REVOKED, &delegation->flags))
break;
err = nfs_delegation_claim_opens(inode, &delegation->stateid,
delegation->type);
if (!issync || err != -EAGAIN)
break;
/*
* Guard against state recovery
*/
err = nfs4_wait_clnt_recover(clp);
} while (err == 0);
if (err) {
nfs_abort_delegation_return(delegation, clp);
goto out;
}
err = nfs_do_return_delegation(inode, delegation, issync);
out:
/* Refcount matched in nfs_start_delegation_return_locked() */
nfs_put_delegation(delegation);
return err;
}
static bool nfs_delegation_need_return(struct nfs_delegation *delegation)
{
bool ret = false;
if (test_and_clear_bit(NFS_DELEGATION_RETURN, &delegation->flags))
ret = true;
else if (test_bit(NFS_DELEGATION_RETURN_IF_CLOSED, &delegation->flags)) {
struct inode *inode;
spin_lock(&delegation->lock);
inode = delegation->inode;
if (inode && list_empty(&NFS_I(inode)->open_files))
ret = true;
spin_unlock(&delegation->lock);
}
if (ret)
clear_bit(NFS_DELEGATION_RETURN_IF_CLOSED, &delegation->flags);
if (test_bit(NFS_DELEGATION_RETURNING, &delegation->flags) ||
test_bit(NFS_DELEGATION_REVOKED, &delegation->flags))
ret = false;
return ret;
}
static int nfs_server_return_marked_delegations(struct nfs_server *server,
void __always_unused *data)
{
struct nfs_delegation *delegation;
struct nfs_delegation *prev;
struct inode *inode;
struct inode *place_holder = NULL;
struct nfs_delegation *place_holder_deleg = NULL;
int err = 0;
restart:
/*
* To avoid quadratic looping we hold a reference
* to an inode place_holder. Each time we restart, we
* list delegation in the server from the delegations
* of that inode.
* prev is an RCU-protected pointer to a delegation which
* wasn't marked for return and might be a good choice for
* the next place_holder.
*/
prev = NULL;
delegation = NULL;
rcu_read_lock();
if (place_holder)
delegation = rcu_dereference(NFS_I(place_holder)->delegation);
if (!delegation || delegation != place_holder_deleg)
delegation = list_entry_rcu(server->delegations.next,
struct nfs_delegation, super_list);
list_for_each_entry_from_rcu(delegation, &server->delegations, super_list) {
struct inode *to_put = NULL;
if (test_bit(NFS_DELEGATION_INODE_FREEING, &delegation->flags))
continue;
if (!nfs_delegation_need_return(delegation)) {
if (nfs4_is_valid_delegation(delegation, 0))
prev = delegation;
continue;
}
if (prev) {
struct inode *tmp = nfs_delegation_grab_inode(prev);
if (tmp) {
to_put = place_holder;
place_holder = tmp;
place_holder_deleg = prev;
}
}
inode = nfs_delegation_grab_inode(delegation);
if (inode == NULL) {
rcu_read_unlock();
iput(to_put);
goto restart;
}
delegation = nfs_start_delegation_return_locked(NFS_I(inode));
rcu_read_unlock();
iput(to_put);
err = nfs_end_delegation_return(inode, delegation, 0);
iput(inode);
cond_resched();
if (!err)
goto restart;
set_bit(NFS4CLNT_DELEGRETURN, &server->nfs_client->cl_state);
goto out;
}
rcu_read_unlock();
out:
iput(place_holder);
return err;
}
/**
* nfs_client_return_marked_delegations - return previously marked delegations
* @clp: nfs_client to process
*
* Note that this function is designed to be called by the state
* manager thread. For this reason, it cannot flush the dirty data,
* since that could deadlock in case of a state recovery error.
*
* Returns zero on success, or a negative errno value.
*/
int nfs_client_return_marked_delegations(struct nfs_client *clp)
{
return nfs_client_for_each_server(clp,
nfs_server_return_marked_delegations, NULL);
}
/**
* nfs_inode_evict_delegation - return delegation, don't reclaim opens
* @inode: inode to process
*
* Does not protect against delegation reclaims, therefore really only safe
* to be called from nfs4_clear_inode(). Guaranteed to always free
* the delegation structure.
*/
void nfs_inode_evict_delegation(struct inode *inode)
{
struct nfs_delegation *delegation;
delegation = nfs_inode_detach_delegation(inode);
if (delegation != NULL) {
set_bit(NFS_DELEGATION_RETURNING, &delegation->flags);
set_bit(NFS_DELEGATION_INODE_FREEING, &delegation->flags);
nfs_do_return_delegation(inode, delegation, 1);
nfs_free_delegation(delegation);
}
}
/**
* nfs_inode_return_delegation - synchronously return a delegation
* @inode: inode to process
*
* This routine will always flush any dirty data to disk on the
* assumption that if we need to return the delegation, then
* we should stop caching.
*
* Returns zero on success, or a negative errno value.
*/
int nfs4_inode_return_delegation(struct inode *inode)
{
struct nfs_inode *nfsi = NFS_I(inode);
struct nfs_delegation *delegation;
int err = 0;
nfs_wb_all(inode);
delegation = nfs_start_delegation_return(nfsi);
if (delegation != NULL)
err = nfs_end_delegation_return(inode, delegation, 1);
return err;
}
/**
* nfs_inode_return_delegation_on_close - asynchronously return a delegation
* @inode: inode to process
*
* This routine is called on file close in order to determine if the
* inode delegation needs to be returned immediately.
*/
void nfs4_inode_return_delegation_on_close(struct inode *inode)
{
struct nfs_delegation *delegation;
struct nfs_delegation *ret = NULL;
if (!inode)
return;
rcu_read_lock();
delegation = nfs4_get_valid_delegation(inode);
if (!delegation)
goto out;
if (test_bit(NFS_DELEGATION_RETURN_IF_CLOSED, &delegation->flags) ||
atomic_long_read(&nfs_active_delegations) >= nfs_delegation_watermark) {
spin_lock(&delegation->lock);
if (delegation->inode &&
list_empty(&NFS_I(inode)->open_files) &&
!test_and_set_bit(NFS_DELEGATION_RETURNING, &delegation->flags)) {
clear_bit(NFS_DELEGATION_RETURN_IF_CLOSED, &delegation->flags);
/* Refcount matched in nfs_end_delegation_return() */
ret = nfs_get_delegation(delegation);
}
spin_unlock(&delegation->lock);
if (ret)
nfs_clear_verifier_delegated(inode);
}
out:
rcu_read_unlock();
nfs_end_delegation_return(inode, ret, 0);
}
/**
* nfs4_inode_make_writeable
* @inode: pointer to inode
*
* Make the inode writeable by returning the delegation if necessary
*
* Returns zero on success, or a negative errno value.
*/
int nfs4_inode_make_writeable(struct inode *inode)
{
struct nfs_delegation *delegation;
rcu_read_lock();
delegation = nfs4_get_valid_delegation(inode);
if (delegation == NULL ||
(nfs4_has_session(NFS_SERVER(inode)->nfs_client) &&
(delegation->type & FMODE_WRITE))) {
rcu_read_unlock();
return 0;
}
rcu_read_unlock();
return nfs4_inode_return_delegation(inode);
}
static void nfs_mark_return_if_closed_delegation(struct nfs_server *server,
struct nfs_delegation *delegation)
{
set_bit(NFS_DELEGATION_RETURN_IF_CLOSED, &delegation->flags);
set_bit(NFS4CLNT_DELEGRETURN, &server->nfs_client->cl_state);
}
static void nfs_mark_return_delegation(struct nfs_server *server,
struct nfs_delegation *delegation)
{
set_bit(NFS_DELEGATION_RETURN, &delegation->flags);
set_bit(NFS4CLNT_DELEGRETURN, &server->nfs_client->cl_state);
}
static bool nfs_server_mark_return_all_delegations(struct nfs_server *server)
{
struct nfs_delegation *delegation;
bool ret = false;
list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
nfs_mark_return_delegation(server, delegation);
ret = true;
}
return ret;
}
static void nfs_client_mark_return_all_delegations(struct nfs_client *clp)
{
struct nfs_server *server;
rcu_read_lock();
list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
nfs_server_mark_return_all_delegations(server);
rcu_read_unlock();
}
static void nfs_delegation_run_state_manager(struct nfs_client *clp)
{
if (test_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state))
nfs4_schedule_state_manager(clp);
}
/**
* nfs_expire_all_delegations
* @clp: client to process
*
*/
void nfs_expire_all_delegations(struct nfs_client *clp)
{
nfs_client_mark_return_all_delegations(clp);
nfs_delegation_run_state_manager(clp);
}
/**
* nfs_super_return_all_delegations - return delegations for one superblock
* @server: pointer to nfs_server to process
*
*/
void nfs_server_return_all_delegations(struct nfs_server *server)
{
struct nfs_client *clp = server->nfs_client;
bool need_wait;
if (clp == NULL)
return;
rcu_read_lock();
need_wait = nfs_server_mark_return_all_delegations(server);
rcu_read_unlock();
if (need_wait) {
nfs4_schedule_state_manager(clp);
nfs4_wait_clnt_recover(clp);
}
}
static void nfs_mark_return_unused_delegation_types(struct nfs_server *server,
fmode_t flags)
{
struct nfs_delegation *delegation;
list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
if ((delegation->type == (FMODE_READ|FMODE_WRITE)) && !(flags & FMODE_WRITE))
continue;
if (delegation->type & flags)
nfs_mark_return_if_closed_delegation(server, delegation);
}
}
static void nfs_client_mark_return_unused_delegation_types(struct nfs_client *clp,
fmode_t flags)
{
struct nfs_server *server;
rcu_read_lock();
list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
nfs_mark_return_unused_delegation_types(server, flags);
rcu_read_unlock();
}
static void nfs_revoke_delegation(struct inode *inode,
const nfs4_stateid *stateid)
{
struct nfs_delegation *delegation;
nfs4_stateid tmp;
bool ret = false;
rcu_read_lock();
delegation = rcu_dereference(NFS_I(inode)->delegation);
if (delegation == NULL)
goto out;
if (stateid == NULL) {
nfs4_stateid_copy(&tmp, &delegation->stateid);
stateid = &tmp;
} else {
if (!nfs4_stateid_match_other(stateid, &delegation->stateid))
goto out;
spin_lock(&delegation->lock);
if (stateid->seqid) {
if (nfs4_stateid_is_newer(&delegation->stateid, stateid)) {
spin_unlock(&delegation->lock);
goto out;
}
delegation->stateid.seqid = stateid->seqid;
}
spin_unlock(&delegation->lock);
}
nfs_mark_delegation_revoked(delegation);
ret = true;
out:
rcu_read_unlock();
if (ret)
nfs_inode_find_state_and_recover(inode, stateid);
}
void nfs_remove_bad_delegation(struct inode *inode,
const nfs4_stateid *stateid)
{
nfs_revoke_delegation(inode, stateid);
}
EXPORT_SYMBOL_GPL(nfs_remove_bad_delegation);
void nfs_delegation_mark_returned(struct inode *inode,
const nfs4_stateid *stateid)
{
struct nfs_delegation *delegation;
if (!inode)
return;
rcu_read_lock();
delegation = rcu_dereference(NFS_I(inode)->delegation);
if (!delegation)
goto out_rcu_unlock;
spin_lock(&delegation->lock);
if (!nfs4_stateid_match_other(stateid, &delegation->stateid))
goto out_spin_unlock;
if (stateid->seqid) {
/* If delegation->stateid is newer, dont mark as returned */
if (nfs4_stateid_is_newer(&delegation->stateid, stateid))
goto out_clear_returning;
if (delegation->stateid.seqid != stateid->seqid)
delegation->stateid.seqid = stateid->seqid;
}
nfs_mark_delegation_revoked(delegation);
out_clear_returning:
clear_bit(NFS_DELEGATION_RETURNING, &delegation->flags);
out_spin_unlock:
spin_unlock(&delegation->lock);
out_rcu_unlock:
rcu_read_unlock();
nfs_inode_find_state_and_recover(inode, stateid);
}
/**
* nfs_expire_unused_delegation_types
* @clp: client to process
* @flags: delegation types to expire
*
*/
void nfs_expire_unused_delegation_types(struct nfs_client *clp, fmode_t flags)
{
nfs_client_mark_return_unused_delegation_types(clp, flags);
nfs_delegation_run_state_manager(clp);
}
static void nfs_mark_return_unreferenced_delegations(struct nfs_server *server)
{
struct nfs_delegation *delegation;
list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
if (test_and_clear_bit(NFS_DELEGATION_REFERENCED, &delegation->flags))
continue;
nfs_mark_return_if_closed_delegation(server, delegation);
}
}
/**
* nfs_expire_unreferenced_delegations - Eliminate unused delegations
* @clp: nfs_client to process
*
*/
void nfs_expire_unreferenced_delegations(struct nfs_client *clp)
{
struct nfs_server *server;
rcu_read_lock();
list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
nfs_mark_return_unreferenced_delegations(server);
rcu_read_unlock();
nfs_delegation_run_state_manager(clp);
}
/**
* nfs_async_inode_return_delegation - asynchronously return a delegation
* @inode: inode to process
* @stateid: state ID information
*
* Returns zero on success, or a negative errno value.
*/
int nfs_async_inode_return_delegation(struct inode *inode,
const nfs4_stateid *stateid)
{
struct nfs_server *server = NFS_SERVER(inode);
struct nfs_client *clp = server->nfs_client;
struct nfs_delegation *delegation;
rcu_read_lock();
delegation = nfs4_get_valid_delegation(inode);
if (delegation == NULL)
goto out_enoent;
if (stateid != NULL &&
!clp->cl_mvops->match_stateid(&delegation->stateid, stateid))
goto out_enoent;
nfs_mark_return_delegation(server, delegation);
rcu_read_unlock();
nfs_delegation_run_state_manager(clp);
return 0;
out_enoent:
rcu_read_unlock();
return -ENOENT;
}
static struct inode *
nfs_delegation_find_inode_server(struct nfs_server *server,
const struct nfs_fh *fhandle)
{
struct nfs_delegation *delegation;
struct inode *freeme, *res = NULL;
list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
spin_lock(&delegation->lock);
if (delegation->inode != NULL &&
!test_bit(NFS_DELEGATION_REVOKED, &delegation->flags) &&
nfs_compare_fh(fhandle, &NFS_I(delegation->inode)->fh) == 0) {
freeme = igrab(delegation->inode);
if (freeme && nfs_sb_active(freeme->i_sb))
res = freeme;
spin_unlock(&delegation->lock);
if (res != NULL)
return res;
if (freeme) {
rcu_read_unlock();
iput(freeme);
rcu_read_lock();
}
return ERR_PTR(-EAGAIN);
}
spin_unlock(&delegation->lock);
}
return ERR_PTR(-ENOENT);
}
/**
* nfs_delegation_find_inode - retrieve the inode associated with a delegation
* @clp: client state handle
* @fhandle: filehandle from a delegation recall
*
* Returns pointer to inode matching "fhandle," or NULL if a matching inode
* cannot be found.
*/
struct inode *nfs_delegation_find_inode(struct nfs_client *clp,
const struct nfs_fh *fhandle)
{
struct nfs_server *server;
struct inode *res;
rcu_read_lock();
list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
res = nfs_delegation_find_inode_server(server, fhandle);
if (res != ERR_PTR(-ENOENT)) {
rcu_read_unlock();
return res;
}
}
rcu_read_unlock();
return ERR_PTR(-ENOENT);
}
static void nfs_delegation_mark_reclaim_server(struct nfs_server *server)
{
struct nfs_delegation *delegation;
list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
/*
* If the delegation may have been admin revoked, then we
* cannot reclaim it.
*/
if (test_bit(NFS_DELEGATION_TEST_EXPIRED, &delegation->flags))
continue;
set_bit(NFS_DELEGATION_NEED_RECLAIM, &delegation->flags);
}
}
/**
* nfs_delegation_mark_reclaim - mark all delegations as needing to be reclaimed
* @clp: nfs_client to process
*
*/
void nfs_delegation_mark_reclaim(struct nfs_client *clp)
{
struct nfs_server *server;
rcu_read_lock();
list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
nfs_delegation_mark_reclaim_server(server);
rcu_read_unlock();
}
static int nfs_server_reap_unclaimed_delegations(struct nfs_server *server,
void __always_unused *data)
{
struct nfs_delegation *delegation;
struct inode *inode;
restart:
rcu_read_lock();
restart_locked:
list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
if (test_bit(NFS_DELEGATION_INODE_FREEING,
&delegation->flags) ||
test_bit(NFS_DELEGATION_RETURNING,
&delegation->flags) ||
test_bit(NFS_DELEGATION_NEED_RECLAIM,
&delegation->flags) == 0)
continue;
inode = nfs_delegation_grab_inode(delegation);
if (inode == NULL)
goto restart_locked;
delegation = nfs_start_delegation_return_locked(NFS_I(inode));
rcu_read_unlock();
if (delegation != NULL) {
if (nfs_detach_delegation(NFS_I(inode), delegation,
server) != NULL)
nfs_free_delegation(delegation);
/* Match nfs_start_delegation_return_locked */
nfs_put_delegation(delegation);
}
iput(inode);
cond_resched();
goto restart;
}
rcu_read_unlock();
return 0;
}
/**
* nfs_delegation_reap_unclaimed - reap unclaimed delegations after reboot recovery is done
* @clp: nfs_client to process
*
*/
void nfs_delegation_reap_unclaimed(struct nfs_client *clp)
{
nfs_client_for_each_server(clp, nfs_server_reap_unclaimed_delegations,
NULL);
}
static inline bool nfs4_server_rebooted(const struct nfs_client *clp)
{
return (clp->cl_state & (BIT(NFS4CLNT_CHECK_LEASE) |
BIT(NFS4CLNT_LEASE_EXPIRED) |
BIT(NFS4CLNT_SESSION_RESET))) != 0;
}
static void nfs_mark_test_expired_delegation(struct nfs_server *server,
struct nfs_delegation *delegation)
{
if (delegation->stateid.type == NFS4_INVALID_STATEID_TYPE)
return;
clear_bit(NFS_DELEGATION_NEED_RECLAIM, &delegation->flags);
set_bit(NFS_DELEGATION_TEST_EXPIRED, &delegation->flags);
set_bit(NFS4CLNT_DELEGATION_EXPIRED, &server->nfs_client->cl_state);
}
static void nfs_inode_mark_test_expired_delegation(struct nfs_server *server,
struct inode *inode)
{
struct nfs_delegation *delegation;
rcu_read_lock();
delegation = rcu_dereference(NFS_I(inode)->delegation);
if (delegation)
nfs_mark_test_expired_delegation(server, delegation);
rcu_read_unlock();
}
static void nfs_delegation_mark_test_expired_server(struct nfs_server *server)
{
struct nfs_delegation *delegation;
list_for_each_entry_rcu(delegation, &server->delegations, super_list)
nfs_mark_test_expired_delegation(server, delegation);
}
/**
* nfs_mark_test_expired_all_delegations - mark all delegations for testing
* @clp: nfs_client to process
*
* Iterates through all the delegations associated with this server and
* marks them as needing to be checked for validity.
*/
void nfs_mark_test_expired_all_delegations(struct nfs_client *clp)
{
struct nfs_server *server;
rcu_read_lock();
list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
nfs_delegation_mark_test_expired_server(server);
rcu_read_unlock();
}
/**
* nfs_test_expired_all_delegations - test all delegations for a client
* @clp: nfs_client to process
*
* Helper for handling "recallable state revoked" status from server.
*/
void nfs_test_expired_all_delegations(struct nfs_client *clp)
{
nfs_mark_test_expired_all_delegations(clp);
nfs4_schedule_state_manager(clp);
}
static void
nfs_delegation_test_free_expired(struct inode *inode,
nfs4_stateid *stateid,
const struct cred *cred)
{
struct nfs_server *server = NFS_SERVER(inode);
const struct nfs4_minor_version_ops *ops = server->nfs_client->cl_mvops;
int status;
if (!cred)
return;
status = ops->test_and_free_expired(server, stateid, cred);
if (status == -NFS4ERR_EXPIRED || status == -NFS4ERR_BAD_STATEID)
nfs_remove_bad_delegation(inode, stateid);
}
static int nfs_server_reap_expired_delegations(struct nfs_server *server,
void __always_unused *data)
{
struct nfs_delegation *delegation;
struct inode *inode;
const struct cred *cred;
nfs4_stateid stateid;
restart:
rcu_read_lock();
restart_locked:
list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
if (test_bit(NFS_DELEGATION_INODE_FREEING,
&delegation->flags) ||
test_bit(NFS_DELEGATION_RETURNING,
&delegation->flags) ||
test_bit(NFS_DELEGATION_TEST_EXPIRED,
&delegation->flags) == 0)
continue;
inode = nfs_delegation_grab_inode(delegation);
if (inode == NULL)
goto restart_locked;
spin_lock(&delegation->lock);
cred = get_cred_rcu(delegation->cred);
nfs4_stateid_copy(&stateid, &delegation->stateid);
spin_unlock(&delegation->lock);
clear_bit(NFS_DELEGATION_TEST_EXPIRED, &delegation->flags);
rcu_read_unlock();
nfs_delegation_test_free_expired(inode, &stateid, cred);
put_cred(cred);
if (!nfs4_server_rebooted(server->nfs_client)) {
iput(inode);
cond_resched();
goto restart;
}
nfs_inode_mark_test_expired_delegation(server,inode);
iput(inode);
return -EAGAIN;
}
rcu_read_unlock();
return 0;
}
/**
* nfs_reap_expired_delegations - reap expired delegations
* @clp: nfs_client to process
*
* Iterates through all the delegations associated with this server and
* checks if they have may have been revoked. This function is usually
* expected to be called in cases where the server may have lost its
* lease.
*/
void nfs_reap_expired_delegations(struct nfs_client *clp)
{
nfs_client_for_each_server(clp, nfs_server_reap_expired_delegations,
NULL);
}
void nfs_inode_find_delegation_state_and_recover(struct inode *inode,
const nfs4_stateid *stateid)
{
struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
struct nfs_delegation *delegation;
bool found = false;
rcu_read_lock();
delegation = rcu_dereference(NFS_I(inode)->delegation);
if (delegation &&
nfs4_stateid_match_or_older(&delegation->stateid, stateid) &&
!test_bit(NFS_DELEGATION_REVOKED, &delegation->flags)) {
nfs_mark_test_expired_delegation(NFS_SERVER(inode), delegation);
found = true;
}
rcu_read_unlock();
if (found)
nfs4_schedule_state_manager(clp);
}
/**
* nfs_delegations_present - check for existence of delegations
* @clp: client state handle
*
* Returns one if there are any nfs_delegation structures attached
* to this nfs_client.
*/
int nfs_delegations_present(struct nfs_client *clp)
{
struct nfs_server *server;
int ret = 0;
rcu_read_lock();
list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
if (!list_empty(&server->delegations)) {
ret = 1;
break;
}
rcu_read_unlock();
return ret;
}
/**
* nfs4_refresh_delegation_stateid - Update delegation stateid seqid
* @dst: stateid to refresh
* @inode: inode to check
*
* Returns "true" and updates "dst->seqid" * if inode had a delegation
* that matches our delegation stateid. Otherwise "false" is returned.
*/
bool nfs4_refresh_delegation_stateid(nfs4_stateid *dst, struct inode *inode)
{
struct nfs_delegation *delegation;
bool ret = false;
if (!inode)
goto out;
rcu_read_lock();
delegation = rcu_dereference(NFS_I(inode)->delegation);
if (delegation != NULL &&
nfs4_stateid_match_other(dst, &delegation->stateid) &&
nfs4_stateid_is_newer(&delegation->stateid, dst) &&
!test_bit(NFS_DELEGATION_REVOKED, &delegation->flags)) {
dst->seqid = delegation->stateid.seqid;
ret = true;
}
rcu_read_unlock();
out:
return ret;
}
/**
* nfs4_copy_delegation_stateid - Copy inode's state ID information
* @inode: inode to check
* @flags: delegation type requirement
* @dst: stateid data structure to fill in
* @cred: optional argument to retrieve credential
*
* Returns "true" and fills in "dst->data" * if inode had a delegation,
* otherwise "false" is returned.
*/
bool nfs4_copy_delegation_stateid(struct inode *inode, fmode_t flags,
nfs4_stateid *dst, const struct cred **cred)
{
struct nfs_inode *nfsi = NFS_I(inode);
struct nfs_delegation *delegation;
bool ret = false;
flags &= FMODE_READ|FMODE_WRITE;
rcu_read_lock();
delegation = rcu_dereference(nfsi->delegation);
if (!delegation)
goto out;
spin_lock(&delegation->lock);
ret = nfs4_is_valid_delegation(delegation, flags);
if (ret) {
nfs4_stateid_copy(dst, &delegation->stateid);
nfs_mark_delegation_referenced(delegation);
if (cred)
*cred = get_cred(delegation->cred);
}
spin_unlock(&delegation->lock);
out:
rcu_read_unlock();
return ret;
}
/**
* nfs4_delegation_flush_on_close - Check if we must flush file on close
* @inode: inode to check
*
* This function checks the number of outstanding writes to the file
* against the delegation 'space_limit' field to see if
* the spec requires us to flush the file on close.
*/
bool nfs4_delegation_flush_on_close(const struct inode *inode)
{
struct nfs_inode *nfsi = NFS_I(inode);
struct nfs_delegation *delegation;
bool ret = true;
rcu_read_lock();
delegation = rcu_dereference(nfsi->delegation);
if (delegation == NULL || !(delegation->type & FMODE_WRITE))
goto out;
if (atomic_long_read(&nfsi->nrequests) < delegation->pagemod_limit)
ret = false;
out:
rcu_read_unlock();
return ret;
}
module_param_named(delegation_watermark, nfs_delegation_watermark, uint, 0644);
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