// 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 unsigned nfs_delegation_watermark = NFS_DEFAULT_DELEGATION_WATERMARK;

module_param_named(delegation_watermark, nfs_delegation_watermark, uint, 0644);

bool directory_delegations = true;

module_param(directory_delegations, bool, 0644);

MODULE_PARM_DESC(directory_delegations,

"Enable the use of directory delegations, defaults to on.");

static struct hlist_head *nfs_delegation_hash(struct nfs_server *server,

const struct nfs_fh *fhandle)

{

return server->delegation_hash_table +

(nfs_fhandle_hash(fhandle) & server->delegation_hash_mask);

}

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_server *server,

struct nfs_delegation *delegation)

{

bool put_ref = false;

if (test_and_set_bit(NFS_DELEGATION_REVOKED, &delegation->flags))

return;

delegation->stateid.type = NFS4_INVALID_STATEID_TYPE;

atomic_long_dec(&server->nr_active_delegations);

if (!test_bit(NFS_DELEGATION_RETURNING, &delegation->flags))

nfs_clear_verifier_delegated(delegation->inode);

spin_lock(&server->delegations_lock);

if (!list_empty(&delegation->entry)) {

list_del_init(&delegation->entry);

put_ref = true;

}

spin_unlock(&server->delegations_lock);

if (put_ref)

nfs_put_delegation(delegation);

}

void nfs_put_delegation(struct nfs_delegation *delegation)

{

if (refcount_dec_and_test(&delegation->refcount))

__nfs_free_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 void nfs_mark_return_delegation(struct nfs_server *server,

struct nfs_delegation *delegation)

{

spin_lock(&server->delegations_lock);

if (list_empty(&delegation->entry))

refcount_inc(&delegation->refcount);

list_move_tail(&delegation->entry, &server->delegations_return);

spin_unlock(&server->delegations_lock);

set_bit(NFS4CLNT_DELEGRETURN, &server->nfs_client->cl_state);

}

static bool nfs4_is_valid_delegation(const struct nfs_delegation *delegation,

fmode_t type)

{

if (delegation != NULL && (delegation->type & type) == type &&

!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;

rcu_read_lock();

delegation = rcu_dereference(NFS_I(inode)->delegation);

if (!nfs4_is_valid_delegation(delegation, 0) ||

!refcount_inc_not_zero(&delegation->refcount))

delegation = NULL;

rcu_read_unlock();

return delegation;

}

static int nfs4_do_check_delegation(struct inode *inode, fmode_t type,

int flags, bool mark)

{

struct nfs_delegation *delegation;

int ret = 0;

type &= FMODE_READ|FMODE_WRITE;

rcu_read_lock();

delegation = rcu_dereference(NFS_I(inode)->delegation);

if (nfs4_is_valid_delegation(delegation, type)) {

if (mark)

nfs_mark_delegation_referenced(delegation);

ret = 1;

if ((flags & NFS_DELEGATION_FLAG_TIME) &&

!test_bit(NFS_DELEGATION_DELEGTIME, &delegation->flags))

ret = 0;

}

rcu_read_unlock();

return ret;

}

/**

* nfs4_have_delegation - check if inode has a delegation, mark it

* NFS_DELEGATION_REFERENCED if there is one.

* @inode: inode to check

* @type: delegation types to check for

* @flags: various modifiers

*

* Returns one if inode has the indicated delegation, otherwise zero.

*/

int nfs4_have_delegation(struct inode *inode, fmode_t type, int flags)

{

if (S_ISDIR(inode->i_mode) && !directory_delegations)

nfs4_inode_set_return_delegation_on_close(inode);

return nfs4_do_check_delegation(inode, type, 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 type)

{

return nfs4_do_check_delegation(inode, type, 0, 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 = locks_inode_context(inode);

struct list_head *list;

int status = 0;

if (flctx == NULL)

goto out;

list = &flctx->flc_posix;

spin_lock(&flctx->flc_lock);

restart:

for_each_file_lock(fl, list) {

if (nfs_file_open_context(fl->c.flc_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;

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);

err = nfs4_open_delegation_recall(ctx, state, stateid);

if (!err)

err = nfs_delegation_claim_locks(state, stateid);

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"

* @deleg_type: raw delegation type

*

*/

void nfs_inode_reclaim_delegation(struct inode *inode, const struct cred *cred,

fmode_t type, const nfs4_stateid *stateid,

unsigned long pagemod_limit, u32 deleg_type)

{

struct nfs_delegation *delegation;

const struct cred *oldcred = NULL;

rcu_read_lock();

delegation = rcu_dereference(NFS_I(inode)->delegation);

if (!delegation) {

rcu_read_unlock();

nfs_inode_set_delegation(inode, cred, type, stateid,

pagemod_limit, deleg_type);

return;

}

spin_lock(&delegation->lock);

nfs4_stateid_copy(&delegation->stateid, stateid);

delegation->type = type;

delegation->pagemod_limit = pagemod_limit;

oldcred = delegation->cred;

delegation->cred = get_cred(cred);

switch (deleg_type) {

case NFS4_OPEN_DELEGATE_READ_ATTRS_DELEG:

case NFS4_OPEN_DELEGATE_WRITE_ATTRS_DELEG:

set_bit(NFS_DELEGATION_DELEGTIME, &delegation->flags);

break;

default:

clear_bit(NFS_DELEGATION_DELEGTIME, &delegation->flags);

}

clear_bit(NFS_DELEGATION_NEED_RECLAIM, &delegation->flags);

if (test_and_clear_bit(NFS_DELEGATION_REVOKED, &delegation->flags))

atomic_long_inc(&NFS_SERVER(inode)->nr_active_delegations);

spin_unlock(&delegation->lock);

rcu_read_unlock();

put_cred(oldcred);

trace_nfs4_reclaim_delegation(inode, type);

}

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,

delegation, 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);

spin_unlock(&delegation->lock);

return inode;

}

static struct nfs_delegation *

nfs_start_delegation_return(struct nfs_inode *nfsi)

{

struct nfs_delegation *delegation;

bool return_now = false;

rcu_read_lock();

delegation = rcu_dereference(nfsi->delegation);

if (!delegation || !refcount_inc_not_zero(&delegation->refcount)) {

rcu_read_unlock();

return NULL;

}

rcu_read_unlock();

spin_lock(&delegation->lock);

if (delegation->inode &&

!test_and_set_bit(NFS_DELEGATION_RETURNING, &delegation->flags))

return_now = true;

spin_unlock(&delegation->lock);

if (!return_now) {

nfs_put_delegation(delegation);

return NULL;

}

nfs_clear_verifier_delegated(&nfsi->vfs_inode);

return delegation;

}

static bool

nfs_detach_delegations_locked(struct nfs_inode *nfsi,

struct nfs_delegation *delegation,

struct nfs_client *clp)

{

lockdep_assert_held(&clp->cl_lock);

trace_nfs4_detach_delegation(&nfsi->vfs_inode, delegation->type);

spin_lock(&delegation->lock);

if (!delegation->inode) {

spin_unlock(&delegation->lock);

return false;

}

hlist_del_init_rcu(&delegation->hash);

list_del_rcu(&delegation->super_list);

delegation->inode = NULL;

rcu_assign_pointer(nfsi->delegation, NULL);

spin_unlock(&delegation->lock);

clear_bit(NFS_INO_REQ_DIR_DELEG, &nfsi->flags);

return true;

}

static bool nfs_detach_delegation(struct nfs_inode *nfsi,

struct nfs_delegation *delegation,

struct nfs_server *server)

{

struct nfs_client *clp = server->nfs_client;

struct nfs_delegation *deleg_cur;

bool ret = false;

spin_lock(&clp->cl_lock);

deleg_cur = rcu_dereference_protected(nfsi->delegation,

lockdep_is_held(&clp->cl_lock));

if (delegation == deleg_cur)

ret = nfs_detach_delegations_locked(nfsi, delegation, clp);

spin_unlock(&clp->cl_lock);

return ret;

}

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_server *server,

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(&server->nr_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"

* @deleg_type: raw delegation type

*

* 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, u32 deleg_type)

{

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_obj(*delegation, GFP_KERNEL_ACCOUNT);

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;

INIT_LIST_HEAD(&delegation->entry);

switch (deleg_type) {

case NFS4_OPEN_DELEGATE_READ_ATTRS_DELEG:

case NFS4_OPEN_DELEGATE_WRITE_ATTRS_DELEG:

delegation->flags |= BIT(NFS_DELEGATION_DELEGTIME);

}

delegation->test_gen = 0;

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(server, 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;

}

if (!nfs_detach_delegations_locked(nfsi, old_delegation, clp))

goto out;

freeme = old_delegation;

add_new:

/*

* If we didn't revalidate the change attribute before setting

* the delegation, then pre-emptively ask for a full attribute

* cache revalidation.

*/

spin_lock(&inode->i_lock);

if (NFS_I(inode)->cache_validity & NFS_INO_INVALID_CHANGE)

nfs_set_cache_invalid(inode,

NFS_INO_INVALID_ATIME | NFS_INO_INVALID_CTIME |

NFS_INO_INVALID_MTIME | NFS_INO_INVALID_SIZE |

NFS_INO_INVALID_BLOCKS | NFS_INO_INVALID_NLINK |

NFS_INO_INVALID_OTHER | NFS_INO_INVALID_DATA |

NFS_INO_INVALID_ACCESS | NFS_INO_INVALID_ACL |

NFS_INO_INVALID_XATTR);

spin_unlock(&inode->i_lock);

list_add_tail_rcu(&delegation->super_list, &server->delegations);

hlist_add_head_rcu(&delegation->hash,

nfs_delegation_hash(server, &NFS_I(inode)->fh));

rcu_assign_pointer(nfsi->delegation, delegation);

delegation = NULL;

atomic_long_inc(&server->nr_active_delegations);

trace_nfs4_set_delegation(inode, type);

/* If we hold writebacks and have delegated mtime then update */

if (deleg_type == NFS4_OPEN_DELEGATE_WRITE_ATTRS_DELEG &&

nfs_have_writebacks(inode))

nfs_update_delegated_mtime(inode);

out:

spin_unlock(&clp->cl_lock);

if (delegation != NULL)

__nfs_free_delegation(delegation);

if (freeme != NULL) {

nfs_do_return_delegation(inode, freeme, 0);

nfs_mark_delegation_revoked(server, freeme);

nfs_put_delegation(freeme);

}

return status;

}

/*

* Basic procedure for returning a delegation to the server.

* If @issync is set, wait until state recovery has finished. Otherwise

* return -EAGAIN to the caller if we need more time.

*/

static int nfs_end_delegation_return(struct inode *inode,

struct nfs_delegation *delegation, bool issync)

{

struct nfs_server *server = NFS_SERVER(inode);

unsigned int mode = O_WRONLY | O_RDWR;

int err = 0;

/* Directory delegations don't require any state recovery */

if (!S_ISREG(inode->i_mode))

goto out_return;

if (!issync)

mode |= O_NONBLOCK;

/* Recall of any remaining application leases */

err = break_lease(inode, mode);

while (err == 0) {

if (test_bit(NFS_DELEGATION_REVOKED, &delegation->flags))

break;

err = nfs_delegation_claim_opens(inode, &delegation->stateid,

delegation->type);

if (!err)

break;

if (err != -EAGAIN)

goto abort;

if (!issync)

goto delay;

/*

* Guard against state recovery

*/

err = nfs4_wait_clnt_recover(server->nfs_client);

}

out_return:

return nfs_do_return_delegation(inode, delegation, issync);

delay:

spin_lock(&server->delegations_lock);

if (list_empty(&delegation->entry))

refcount_inc(&delegation->refcount);

list_move_tail(&delegation->entry, &server->delegations_return);

spin_unlock(&server->delegations_lock);

set_bit(NFS4CLNT_DELEGRETURN_DELAYED, &server->nfs_client->cl_state);

abort:

clear_bit(NFS_DELEGATION_RETURNING, &delegation->flags);

return err;

}

static int nfs_return_one_delegation(struct nfs_server *server)

{

struct nfs_delegation *delegation;

struct inode *inode;

int err = 0;

spin_lock(&server->delegations_lock);

delegation = list_first_entry_or_null(&server->delegations_return,

struct nfs_delegation, entry);

if (!delegation) {

spin_unlock(&server->delegations_lock);

return 0; /* no more delegations */

}

list_del_init(&delegation->entry);

spin_unlock(&server->delegations_lock);

spin_lock(&delegation->lock);

inode = delegation->inode;

if (!inode || !igrab(inode)) {

spin_unlock(&delegation->lock);

goto out_put_delegation;

}

if (test_bit(NFS_DELEGATION_REVOKED, &delegation->flags) ||

test_and_set_bit(NFS_DELEGATION_RETURNING, &delegation->flags)) {

spin_unlock(&delegation->lock);

goto out_put_inode;

}

spin_unlock(&delegation->lock);

nfs_clear_verifier_delegated(inode);

err = nfs_end_delegation_return(inode, delegation, false);

out_put_inode:

iput(inode);

out_put_delegation:

nfs_put_delegation(delegation);

if (err)

return err;

return 1; /* keep going */

}

static int nfs_server_return_marked_delegations(struct nfs_server *server,

void __always_unused *data)

{

int err;

while ((err = nfs_return_one_delegation(server)) > 0)

cond_resched();

return err;

}

static inline bool nfs_delegations_over_limit(struct nfs_server *server)

{

return !list_empty_careful(&server->delegations_lru) &&

atomic_long_read(&server->nr_active_delegations) >

nfs_delegation_watermark;

}

static void nfs_delegations_return_from_lru(struct nfs_server *server)

{

struct nfs_delegation *d, *n;

unsigned int pass = 0;

bool moved = false;

retry:

spin_lock(&server->delegations_lock);

list_for_each_entry_safe(d, n, &server->delegations_lru, entry) {

if (!nfs_delegations_over_limit(server))

break;

if (pass == 0 && test_bit(NFS_DELEGATION_REFERENCED, &d->flags))

continue;

list_move_tail(&d->entry, &server->delegations_return);

moved = true;

}

spin_unlock(&server->delegations_lock);

/*

* If we are still over the limit, try to reclaim referenced delegations

* as well.

*/

if (pass == 0 && nfs_delegations_over_limit(server)) {

pass++;

goto retry;

}

if (moved) {

set_bit(NFS4CLNT_DELEGRETURN, &server->nfs_client->cl_state);

nfs4_schedule_state_manager(server->nfs_client);

}

}

static void nfs_delegation_add_lru(struct nfs_server *server,

struct nfs_delegation *delegation)

{

spin_lock(&server->delegations_lock);

if (list_empty(&delegation->entry)) {

list_add_tail(&delegation->entry, &server->delegations_lru);

refcount_inc(&delegation->refcount);

}

spin_unlock(&server->delegations_lock);

if (nfs_delegations_over_limit(server))

nfs_delegations_return_from_lru(server);

}

static bool nfs_server_clear_delayed_delegations(struct nfs_server *server)

{

bool ret = false;

if (list_empty_careful(&server->delegations_delayed))

return false;

spin_lock(&server->delegations_lock);

if (!list_empty(&server->delegations_delayed)) {

list_splice_tail_init(&server->delegations_delayed,

&server->delegations_return);

ret = true;

}

spin_unlock(&server->delegations_lock);

return ret;

}

static bool nfs_client_clear_delayed_delegations(struct nfs_client *clp)

{

struct nfs_server *server;

bool ret = false;

if (!test_and_clear_bit(NFS4CLNT_DELEGRETURN_DELAYED, &clp->cl_state))

return false;

rcu_read_lock();

list_for_each_entry_rcu (server, &clp->cl_superblocks, client_link) {

if (nfs_server_clear_delayed_delegations(server))

ret = true;

}

rcu_read_unlock();

if (ret)

set_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state);

return ret;

}

/**

* 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)

{

int err = nfs_client_for_each_server(

clp, nfs_server_return_marked_delegations, NULL);

if (err)

return err;

/* If a return was delayed, sleep to prevent hard looping */

if (nfs_client_clear_delayed_delegations(clp))

ssleep(1);

return 0;

}

/**

* 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_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 && !nfs_detach_delegation(nfsi, delegation, server))

delegation = NULL;

rcu_read_unlock();

if (!delegation)

return;

set_bit(NFS_DELEGATION_RETURNING, &delegation->flags);

nfs_do_return_delegation(inode, delegation, 1);

nfs_mark_delegation_revoked(server, delegation);

nfs_put_delegation(delegation);

}

/**

* nfs4_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.

*/

void nfs4_inode_return_delegation(struct inode *inode)

{

struct nfs_inode *nfsi = NFS_I(inode);

struct nfs_delegation *delegation;

delegation = nfs_start_delegation_return(nfsi);

if (!delegation)

return;

/* Synchronous recall of any application leases */

break_lease(inode, O_WRONLY | O_RDWR);

if (S_ISREG(inode->i_mode))

nfs_wb_all(inode);

nfs_end_delegation_return(inode, delegation, true);

nfs_put_delegation(delegation);

}

/**

* nfs4_inode_set_return_delegation_on_close - asynchronously return a delegation

* @inode: inode to process

*

* This routine is called to request that the delegation be returned as soon

* as the file is closed. If the file is already closed, the delegation is

* immediately returned.

*/

void nfs4_inode_set_return_delegation_on_close(struct inode *inode)

{

struct nfs_delegation *delegation;

bool return_now = false;

if (!inode)

return;

delegation = nfs4_get_valid_delegation(inode);

if (!delegation)

return;

spin_lock(&delegation->lock);

if (!delegation->inode)

goto out_unlock;

if (list_empty(&NFS_I(inode)->open_files) &&

!test_and_set_bit(NFS_DELEGATION_RETURNING, &delegation->flags))

return_now = true;

else

set_bit(NFS_DELEGATION_RETURN_IF_CLOSED, &delegation->flags);

out_unlock:

spin_unlock(&delegation->lock);

if (return_now) {

nfs_clear_verifier_delegated(inode);

nfs_end_delegation_return(inode, delegation, false);

}

nfs_put_delegation(delegation);

}

/**

* nfs4_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_server *server = NFS_SERVER(inode);

struct nfs_delegation *delegation;

bool return_now = false;

delegation = nfs4_get_valid_delegation(inode);

if (!delegation)

return;

if (test_bit(NFS_DELEGATION_RETURN_IF_CLOSED, &delegation->flags)) {

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);

return_now = true;

}

spin_unlock(&delegation->lock);

}

if (return_now) {

nfs_clear_verifier_delegated(inode);

nfs_end_delegation_return(inode, delegation, false);

} else {

nfs_delegation_add_lru(server, delegation);

}

nfs_put_delegation(delegation);

}

/**

* nfs4_inode_make_writeable

* @inode: pointer to inode

*

* Make the inode writeable by returning the delegation if necessary

*/

void nfs4_inode_make_writeable(struct inode *inode)

{

struct nfs_delegation *delegation;

delegation = nfs4_get_valid_delegation(inode);

if (!delegation)

return;

if (!nfs4_has_session(NFS_SERVER(inode)->nfs_client) ||

!(delegation->type & FMODE_WRITE))

nfs4_inode_return_delegation(inode);

nfs_put_delegation(delegation);

}

static void

nfs_mark_return_if_closed_delegation(struct nfs_server *server,

struct nfs_delegation *delegation)

{

struct inode *inode;

if (!list_empty_careful(&server->delegations_return) ||

test_bit(NFS_DELEGATION_RETURN_IF_CLOSED, &delegation->flags))

return;

spin_lock(&delegation->lock);

inode = delegation->inode;

if (!inode)

goto out;

if (list_empty(&NFS_I(inode)->open_files))

nfs_mark_return_delegation(server, delegation);

else

set_bit(NFS_DELEGATION_RETURN_IF_CLOSED, &delegation->flags);

out:

spin_unlock(&delegation->lock);

}

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_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)

{

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();

nfs_delegation_run_state_manager(clp);

}

/**

* nfs_server_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;