diff options
Diffstat (limited to 'fs/nfs/delegation.c')
| -rw-r--r-- | fs/nfs/delegation.c | 1629 |
1 files changed, 1629 insertions, 0 deletions
diff --git a/fs/nfs/delegation.c b/fs/nfs/delegation.c new file mode 100644 index 000000000..ab3e44146 --- /dev/null +++ b/fs/nfs/delegation.c @@ -0,0 +1,1629 @@ +// 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 nfs_inode *nfsi = NFS_I(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; + + /* Guard against reclaim and new lock/unlock calls */ + down_write(&nfsi->rwsem); + 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) { + up_write(&nfsi->rwsem); + goto out; + } + spin_lock(&flctx->flc_lock); + } + if (list == &flctx->flc_posix) { + list = &flctx->flc_flock; + goto restart; + } + spin_unlock(&flctx->flc_lock); + up_write(&nfsi->rwsem); +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; + bool orphaned = false; + int status = 0; + + delegation = kmalloc_obj(*delegation, GFP_KERNEL_ACCOUNT); + if (delegation == NULL) { + nfs4_proc_delegreturn(inode, cred, stateid, NULL, 0); + 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)) { + orphaned = true; + goto out; + } + } + if (!nfs_detach_delegations_locked(nfsi, old_delegation, clp)) { + orphaned = true; + 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) { + if (orphaned) + nfs_do_return_delegation(inode, delegation, 0); + __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_delayed); + 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; + if (delegation->type & flags) + nfs_mark_return_if_closed_delegation(server, delegation); + } +} + +void nfs_expire_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(); + + nfs_delegation_run_state_manager(clp); +} + +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(NFS_SERVER(inode), delegation); + ret = true; +out: + rcu_read_unlock(); + if (ret) + nfs_inode_find_state_and_recover(inode, stateid); +} + +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(NFS_SERVER(inode), delegation); + clear_bit(NFS_DELEGATION_RETURNING, &delegation->flags); + spin_unlock(&delegation->lock); + if (nfs_detach_delegation(NFS_I(inode), delegation, NFS_SERVER(inode))) + nfs_put_delegation(delegation); + goto out_rcu_unlock; + +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_remove_bad_delegation - handle delegations that are unusable + * @inode: inode to process + * @stateid: the delegation's stateid + * + * If the server ACK-ed our FREE_STATEID then clean + * up the delegation, else mark and keep the revoked state. + */ +void nfs_remove_bad_delegation(struct inode *inode, + const nfs4_stateid *stateid) +{ + if (stateid && stateid->type == NFS4_FREED_STATEID_TYPE) + nfs_delegation_mark_returned(inode, stateid); + else + nfs_revoke_delegation(inode, stateid); +} +EXPORT_SYMBOL_GPL(nfs_remove_bad_delegation); + +static bool nfs_mark_return_unreferenced_delegations(struct nfs_server *server) +{ + struct nfs_delegation *d, *n; + bool marked = false; + + spin_lock(&server->delegations_lock); + list_for_each_entry_safe(d, n, &server->delegations_lru, entry) { + if (test_and_clear_bit(NFS_DELEGATION_REFERENCED, &d->flags)) + continue; + list_move_tail(&d->entry, &server->delegations_return); + marked = true; + } + spin_unlock(&server->delegations_lock); + + return marked; +} + +/** + * 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; + bool marked = false; + + rcu_read_lock(); + list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) + marked |= nfs_mark_return_unreferenced_delegations(server); + rcu_read_unlock(); + + if (marked) { + set_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state); + nfs4_schedule_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; + + delegation = nfs4_get_valid_delegation(inode); + if (!delegation) + return -ENOENT; + + if (stateid != NULL && + !clp->cl_mvops->match_stateid(&delegation->stateid, stateid)) { + nfs_put_delegation(delegation); + return -ENOENT; + } + + nfs_mark_return_delegation(server, delegation); + nfs_put_delegation(delegation); + + /* If there are any application leases or delegations, recall them */ + break_lease(inode, O_WRONLY | O_RDWR | O_NONBLOCK); + + nfs_delegation_run_state_manager(clp); + return 0; +} + +static struct inode * +nfs_delegation_find_inode_server(struct nfs_server *server, + const struct nfs_fh *fhandle) +{ + struct hlist_head *head = nfs_delegation_hash(server, fhandle); + struct nfs_delegation *delegation; + struct super_block *freeme = NULL; + struct inode *res = NULL; + + hlist_for_each_entry_rcu(delegation, head, hash) { + 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) { + if (nfs_sb_active(server->super)) { + freeme = server->super; + res = igrab(delegation->inode); + } + spin_unlock(&delegation->lock); + if (res != NULL) + return res; + if (freeme) { + rcu_read_unlock(); + nfs_sb_deactive(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(); + list_for_each_entry_rcu(delegation, &server->delegations, super_list) { + if (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) + continue; + delegation = nfs_start_delegation_return(NFS_I(inode)); + rcu_read_unlock(); + if (delegation != NULL) { + if (nfs_detach_delegation(NFS_I(inode), delegation, + server)) { + nfs_mark_delegation_revoked(server, delegation); + nfs_put_delegation(delegation); + } + /* Match nfs_start_delegation_return */ + 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(NFS4SERV_DELEGATION_EXPIRED, &server->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; + unsigned long gen = ++server->delegation_gen; + + if (!test_and_clear_bit(NFS4SERV_DELEGATION_EXPIRED, + &server->delegation_flags)) + return 0; +restart: + rcu_read_lock(); + list_for_each_entry_rcu(delegation, &server->delegations, super_list) { + if (test_bit(NFS_DELEGATION_RETURNING, + &delegation->flags) || + test_bit(NFS_DELEGATION_TEST_EXPIRED, + &delegation->flags) == 0 || + delegation->test_gen == gen) + continue; + inode = nfs_delegation_grab_inode(delegation); + if (inode == NULL) + continue; + spin_lock(&delegation->lock); + cred = get_cred_rcu(delegation->cred); + nfs4_stateid_copy(&stateid, &delegation->stateid); + spin_unlock(&delegation->lock); + delegation->test_gen = gen; + 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); + set_bit(NFS4SERV_DELEGATION_EXPIRED, &server->delegation_flags); + set_bit(NFS4CLNT_DELEGATION_EXPIRED, + &server->nfs_client->cl_state); + 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 (atomic_long_read(&server->nr_active_delegations) > 0) { + 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; +} + +int nfs4_delegation_hash_alloc(struct nfs_server *server) +{ + int delegation_buckets, i; + + delegation_buckets = roundup_pow_of_two(nfs_delegation_watermark / 16); + server->delegation_hash_mask = delegation_buckets - 1; + server->delegation_hash_table = kmalloc_objs(*server->delegation_hash_table, + delegation_buckets); + if (!server->delegation_hash_table) + return -ENOMEM; + for (i = 0; i < delegation_buckets; i++) + INIT_HLIST_HEAD(&server->delegation_hash_table[i]); + return 0; +} |