/* * 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/nfs4.h> #include <linux/nfs_fs.h> #include <linux/nfs_xdr.h> #include "nfs4_fs.h" #include "delegation.h" #include "internal.h" static void nfs_free_delegation(struct nfs_delegation *delegation) { if (delegation->cred) { put_rpccred(delegation->cred); delegation->cred = NULL; } kfree_rcu(delegation, rcu); } /** * 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); } /** * nfs_have_delegation - check if inode has a delegation * @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) { struct nfs_delegation *delegation; int ret = 0; flags &= FMODE_READ|FMODE_WRITE; rcu_read_lock(); delegation = rcu_dereference(NFS_I(inode)->delegation); if (delegation != NULL && (delegation->type & flags) == flags) { nfs_mark_delegation_referenced(delegation); ret = 1; } rcu_read_unlock(); return ret; } static int nfs_delegation_claim_locks(struct nfs_open_context *ctx, struct nfs4_state *state) { struct inode *inode = state->inode; struct file_lock *fl; int status = 0; if (inode->i_flock == NULL) goto out; /* Protect inode->i_flock using the file locks lock */ lock_flocks(); for (fl = inode->i_flock; fl != NULL; fl = fl->fl_next) { if (!(fl->fl_flags & (FL_POSIX|FL_FLOCK))) continue; if (nfs_file_open_context(fl->fl_file) != ctx) continue; unlock_flocks(); status = nfs4_lock_delegation_recall(state, fl); if (status < 0) goto out; lock_flocks(); } unlock_flocks(); out: return status; } static int nfs_delegation_claim_opens(struct inode *inode, const nfs4_stateid *stateid) { struct nfs_inode *nfsi = NFS_I(inode); struct nfs_open_context *ctx; struct nfs4_state *state; int err; again: spin_lock(&inode->i_lock); list_for_each_entry(ctx, &nfsi->open_files, list) { state = ctx->state; if (state == NULL) continue; if (!test_bit(NFS_DELEGATED_STATE, &state->flags)) continue; if (!nfs4_stateid_match(&state->stateid, stateid)) continue; get_nfs_open_context(ctx); spin_unlock(&inode->i_lock); err = nfs4_open_delegation_recall(ctx, state, stateid); if (err >= 0) err = nfs_delegation_claim_locks(ctx, state); put_nfs_open_context(ctx); if (err != 0) return err; goto again; } spin_unlock(&inode->i_lock); return 0; } /** * nfs_inode_reclaim_delegation - process a delegation reclaim request * @inode: inode to process * @cred: credential to use for request * @res: new delegation state from server * */ void nfs_inode_reclaim_delegation(struct inode *inode, struct rpc_cred *cred, struct nfs_openres *res) { struct nfs_delegation *delegation; struct rpc_cred *oldcred = NULL; rcu_read_lock(); delegation = rcu_dereference(NFS_I(inode)->delegation); if (delegation != NULL) { spin_lock(&delegation->lock); if (delegation->inode != NULL) { nfs4_stateid_copy(&delegation->stateid, &res->delegation); delegation->type = res->delegation_type; delegation->maxsize = res->maxsize; oldcred = delegation->cred; delegation->cred = get_rpccred(cred); clear_bit(NFS_DELEGATION_NEED_RECLAIM, &delegation->flags); NFS_I(inode)->delegation_state = delegation->type; spin_unlock(&delegation->lock); put_rpccred(oldcred); rcu_read_unlock(); } else { /* We appear to have raced with a delegation return. */ spin_unlock(&delegation->lock); rcu_read_unlock(); nfs_inode_set_delegation(inode, cred, res); } } else { rcu_read_unlock(); } } static int nfs_do_return_delegation(struct inode *inode, struct nfs_delegation *delegation, int issync) { int res = 0; res = nfs4_proc_delegreturn(inode, delegation->cred, &delegation->stateid, issync); nfs_free_delegation(delegation); 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_detach_delegation_locked(struct nfs_inode *nfsi, struct nfs_server *server) { struct nfs_delegation *delegation = rcu_dereference_protected(nfsi->delegation, lockdep_is_held(&server->nfs_client->cl_lock)); if (delegation == NULL) goto nomatch; spin_lock(&delegation->lock); list_del_rcu(&delegation->super_list); delegation->inode = NULL; nfsi->delegation_state = 0; rcu_assign_pointer(nfsi->delegation, NULL); spin_unlock(&delegation->lock); return delegation; nomatch: return NULL; } static struct nfs_delegation *nfs_detach_delegation(struct nfs_inode *nfsi, struct nfs_server *server) { struct nfs_client *clp = server->nfs_client; struct nfs_delegation *delegation; spin_lock(&clp->cl_lock); delegation = nfs_detach_delegation_locked(nfsi, server); spin_unlock(&clp->cl_lock); return delegation; } /** * 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 * @res: new delegation state from server * * Returns zero on success, or a negative errno value. */ int nfs_inode_set_delegation(struct inode *inode, struct rpc_cred *cred, struct nfs_openres *res) { 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, &res->delegation); delegation->type = res->delegation_type; delegation->maxsize = res->maxsize; delegation->change_attr = inode->i_version; delegation->cred = get_rpccred(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) { if (nfs4_stateid_match(&delegation->stateid, &old_delegation->stateid) && delegation->type == old_delegation->type) { goto out; } /* * 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; } freeme = nfs_detach_delegation_locked(nfsi, server); } list_add_rcu(&delegation->super_list, &server->delegations); nfsi->delegation_state = delegation->type; rcu_assign_pointer(nfsi->delegation, delegation); delegation = NULL; /* Ensure we revalidate the attributes and page cache! */ spin_lock(&inode->i_lock); nfsi->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); return status; } /* * Basic procedure for returning a delegation to the server */ static int __nfs_inode_return_delegation(struct inode *inode, struct nfs_delegation *delegation, int issync) { struct nfs_inode *nfsi = NFS_I(inode); int err; /* * Guard against new delegated open/lock/unlock calls and against * state recovery */ down_write(&nfsi->rwsem); err = nfs_delegation_claim_opens(inode, &delegation->stateid); up_write(&nfsi->rwsem); if (err) goto out; err = nfs_do_return_delegation(inode, delegation, issync); out: 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) { struct nfs_delegation *delegation; struct nfs_server *server; struct inode *inode; int err = 0; restart: rcu_read_lock(); list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) { list_for_each_entry_rcu(delegation, &server->delegations, super_list) { if (!test_and_clear_bit(NFS_DELEGATION_RETURN, &delegation->flags)) continue; inode = nfs_delegation_grab_inode(delegation); if (inode == NULL) continue; delegation = nfs_detach_delegation(NFS_I(inode), server); rcu_read_unlock(); if (delegation != NULL) err = __nfs_inode_return_delegation(inode, delegation, 0); iput(inode); if (!err) goto restart; set_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state); return err; } } rcu_read_unlock(); return 0; } /** * nfs_inode_return_delegation_noreclaim - 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(). */ void nfs_inode_return_delegation_noreclaim(struct inode *inode) { struct nfs_server *server = NFS_SERVER(inode); struct nfs_inode *nfsi = NFS_I(inode); struct nfs_delegation *delegation; if (rcu_access_pointer(nfsi->delegation) != NULL) { delegation = nfs_detach_delegation(nfsi, server); if (delegation != NULL) nfs_do_return_delegation(inode, delegation, 0); } } /** * 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_server *server = NFS_SERVER(inode); struct nfs_inode *nfsi = NFS_I(inode); struct nfs_delegation *delegation; int err = 0; nfs_wb_all(inode); if (rcu_access_pointer(nfsi->delegation) != NULL) { delegation = nfs_detach_delegation(nfsi, server); if (delegation != NULL) { err = __nfs_inode_return_delegation(inode, delegation, 1); } } return err; } 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); } /** * nfs_super_return_all_delegations - return delegations for one superblock * @sb: sb to process * */ void nfs_server_return_all_delegations(struct nfs_server *server) { struct nfs_client *clp = server->nfs_client; struct nfs_delegation *delegation; if (clp == NULL) return; rcu_read_lock(); list_for_each_entry_rcu(delegation, &server->delegations, super_list) { spin_lock(&delegation->lock); set_bit(NFS_DELEGATION_RETURN, &delegation->flags); spin_unlock(&delegation->lock); } rcu_read_unlock(); if (nfs_client_return_marked_delegations(clp) != 0) nfs4_schedule_state_manager(clp); } static void nfs_mark_return_all_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_delegation(server, delegation); } } static void nfs_client_mark_return_all_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_all_delegation_types(server, flags); 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); } void nfs_remove_bad_delegation(struct inode *inode) { struct nfs_delegation *delegation; delegation = nfs_detach_delegation(NFS_I(inode), NFS_SERVER(inode)); if (delegation) { nfs_inode_find_state_and_recover(inode, &delegation->stateid); nfs_free_delegation(delegation); } } EXPORT_SYMBOL_GPL(nfs_remove_bad_delegation); /** * nfs_expire_all_delegation_types * @clp: client to process * @flags: delegation types to expire * */ void nfs_expire_all_delegation_types(struct nfs_client *clp, fmode_t flags) { nfs_client_mark_return_all_delegation_types(clp, flags); nfs_delegation_run_state_manager(clp); } /** * nfs_expire_all_delegations * @clp: client to process * */ void nfs_expire_all_delegations(struct nfs_client *clp) { nfs_expire_all_delegation_types(clp, FMODE_READ|FMODE_WRITE); } 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_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; filemap_flush(inode->i_mapping); rcu_read_lock(); delegation = rcu_dereference(NFS_I(inode)->delegation); if (!clp->cl_mvops->match_stateid(&delegation->stateid, stateid)) { rcu_read_unlock(); return -ENOENT; } nfs_mark_return_delegation(server, delegation); rcu_read_unlock(); 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 nfs_delegation *delegation; struct inode *res = NULL; list_for_each_entry_rcu(delegation, &server->delegations, super_list) { spin_lock(&delegation->lock); if (delegation->inode != NULL && nfs_compare_fh(fhandle, &NFS_I(delegation->inode)->fh) == 0) { res = igrab(delegation->inode); } spin_unlock(&delegation->lock); if (res != NULL) break; } return res; } /** * 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 = NULL; rcu_read_lock(); list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) { res = nfs_delegation_find_inode_server(server, fhandle); if (res != NULL) break; } rcu_read_unlock(); return res; } 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) 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(); } /** * 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) { struct nfs_delegation *delegation; struct nfs_server *server; struct inode *inode; restart: rcu_read_lock(); list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) { list_for_each_entry_rcu(delegation, &server->delegations, super_list) { if (test_bit(NFS_DELEGATION_NEED_RECLAIM, &delegation->flags) == 0) continue; inode = nfs_delegation_grab_inode(delegation); if (inode == NULL) continue; delegation = nfs_detach_delegation(NFS_I(inode), server); rcu_read_unlock(); if (delegation != NULL) nfs_free_delegation(delegation); iput(inode); goto restart; } } rcu_read_unlock(); } /** * 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_copy_delegation_stateid - Copy inode's state ID information * @dst: stateid data structure to fill in * @inode: inode to check * @flags: delegation type requirement * * Returns "true" and fills in "dst->data" * if inode had a delegation, * otherwise "false" is returned. */ bool nfs4_copy_delegation_stateid(nfs4_stateid *dst, struct inode *inode, fmode_t flags) { struct nfs_inode *nfsi = NFS_I(inode); struct nfs_delegation *delegation; bool ret; flags &= FMODE_READ|FMODE_WRITE; rcu_read_lock(); delegation = rcu_dereference(nfsi->delegation); ret = (delegation != NULL && (delegation->type & flags) == flags); if (ret) { nfs4_stateid_copy(dst, &delegation->stateid); nfs_mark_delegation_referenced(delegation); } rcu_read_unlock(); return ret; }