fs/nfs/delegation.c

   1 /*
   2  * linux/fs/nfs/delegation.c
   3  *
   4  * Copyright (C) 2004 Trond Myklebust
   5  *
   6  * NFS file delegation management
   7  *
   8  */
   9 #include <linux/config.h>
  10 #include <linux/completion.h>
  11 #include <linux/module.h>
  12 #include <linux/sched.h>
  13 #include <linux/spinlock.h>
  14
  15 #include <linux/nfs4.h>
  16 #include <linux/nfs_fs.h>
  17 #include <linux/nfs_xdr.h>
  18
  19 #include "nfs4_fs.h"
  20 #include "delegation.h"
  21
  22 static struct nfs_delegation *nfs_alloc_delegation(void)
  23 {
  24         return (struct nfs_delegation *)kmalloc(sizeof(struct nfs_delegation), GFP_KERNEL);
  25 }
  26
  27 static void nfs_free_delegation(struct nfs_delegation *delegation)
  28 {
  29         if (delegation->cred)
  30                 put_rpccred(delegation->cred);
  31         kfree(delegation);
  32 }
  33
  34 static void nfs_delegation_claim_opens(struct inode *inode)
  35 {
  36         struct nfs_inode *nfsi = NFS_I(inode);
  37         struct nfs_open_context *ctx;
  38         struct nfs4_state *state;
  39
  40 again:
  41         spin_lock(&inode->i_lock);
  42         list_for_each_entry(ctx, &nfsi->open_files, list) {
  43                 state = ctx->state;
  44                 if (state == NULL)
  45                         continue;
  46                 if (!test_bit(NFS_DELEGATED_STATE, &state->flags))
  47                         continue;
  48                 get_nfs_open_context(ctx);
  49                 spin_unlock(&inode->i_lock);
  50                 if (nfs4_open_delegation_recall(ctx->dentry, state) < 0)
  51                         return;
  52                 put_nfs_open_context(ctx);
  53                 goto again;
  54         }
  55         spin_unlock(&inode->i_lock);
  56 }
  57
  58 /*
  59  * Set up a delegation on an inode
  60  */
  61 void nfs_inode_reclaim_delegation(struct inode *inode, struct rpc_cred *cred, struct nfs_openres *res)
  62 {
  63         struct nfs_delegation *delegation = NFS_I(inode)->delegation;
  64
  65         if (delegation == NULL)
  66                 return;
  67         memcpy(delegation->stateid.data, res->delegation.data,
  68                         sizeof(delegation->stateid.data));
  69         delegation->type = res->delegation_type;
  70         delegation->maxsize = res->maxsize;
  71         put_rpccred(cred);
  72         delegation->cred = get_rpccred(cred);
  73         delegation->flags &= ~NFS_DELEGATION_NEED_RECLAIM;
  74         NFS_I(inode)->delegation_state = delegation->type;
  75         smp_wmb();
  76 }
  77
  78 /*
  79  * Set up a delegation on an inode
  80  */
  81 int nfs_inode_set_delegation(struct inode *inode, struct rpc_cred *cred, struct nfs_openres *res)
  82 {
  83         struct nfs4_client *clp = NFS_SERVER(inode)->nfs4_state;
  84         struct nfs_inode *nfsi = NFS_I(inode);
  85         struct nfs_delegation *delegation;
  86         int status = 0;
  87
  88         delegation = nfs_alloc_delegation();
  89         if (delegation == NULL)
  90                 return -ENOMEM;
  91         memcpy(delegation->stateid.data, res->delegation.data,
  92                         sizeof(delegation->stateid.data));
  93         delegation->type = res->delegation_type;
  94         delegation->maxsize = res->maxsize;
  95         delegation->cred = get_rpccred(cred);
  96         delegation->inode = inode;
  97
  98         spin_lock(&clp->cl_lock);
  99         if (nfsi->delegation == NULL) {
 100                 list_add(&delegation->super_list, &clp->cl_delegations);
 101                 nfsi->delegation = delegation;
 102                 nfsi->delegation_state = delegation->type;
 103                 delegation = NULL;
 104         } else {
 105                 if (memcmp(&delegation->stateid, &nfsi->delegation->stateid,
 106                                         sizeof(delegation->stateid)) != 0 ||
 107                                 delegation->type != nfsi->delegation->type) {
 108                         printk("%s: server %u.%u.%u.%u, handed out a duplicate delegation!\n",
 109                                         __FUNCTION__, NIPQUAD(clp->cl_addr));
 110                         status = -EIO;
 111                 }
 112         }
 113         spin_unlock(&clp->cl_lock);
 114         if (delegation != NULL)
 115                 kfree(delegation);
 116         return status;
 117 }
 118
 119 static int nfs_do_return_delegation(struct inode *inode, struct nfs_delegation *delegation)
 120 {
 121         int res = 0;
 122
 123         __nfs_revalidate_inode(NFS_SERVER(inode), inode);
 124
 125         res = nfs4_proc_delegreturn(inode, delegation->cred, &delegation->stateid);
 126         nfs_free_delegation(delegation);
 127         return res;
 128 }
 129
 130 /* Sync all data to disk upon delegation return */
 131 static void nfs_msync_inode(struct inode *inode)
 132 {
 133         filemap_fdatawrite(inode->i_mapping);
 134         nfs_wb_all(inode);
 135         filemap_fdatawait(inode->i_mapping);
 136 }
 137
 138 /*
 139  * Basic procedure for returning a delegation to the server
 140  */
 141 int nfs_inode_return_delegation(struct inode *inode)
 142 {
 143         struct nfs4_client *clp = NFS_SERVER(inode)->nfs4_state;
 144         struct nfs_inode *nfsi = NFS_I(inode);
 145         struct nfs_delegation *delegation;
 146         int res = 0;
 147
 148         nfs_msync_inode(inode);
 149         down_read(&clp->cl_sem);
 150         /* Guard against new delegated open calls */
 151         down_write(&nfsi->rwsem);
 152         spin_lock(&clp->cl_lock);
 153         delegation = nfsi->delegation;
 154         if (delegation != NULL) {
 155                 list_del_init(&delegation->super_list);
 156                 nfsi->delegation = NULL;
 157                 nfsi->delegation_state = 0;
 158         }
 159         spin_unlock(&clp->cl_lock);
 160         nfs_delegation_claim_opens(inode);
 161         up_write(&nfsi->rwsem);
 162         up_read(&clp->cl_sem);
 163         nfs_msync_inode(inode);
 164
 165         if (delegation != NULL)
 166                 res = nfs_do_return_delegation(inode, delegation);
 167         return res;
 168 }
 169
 170 /*
 171  * Return all delegations associated to a super block
 172  */
 173 void nfs_return_all_delegations(struct super_block *sb)
 174 {
 175         struct nfs4_client *clp = NFS_SB(sb)->nfs4_state;
 176         struct nfs_delegation *delegation;
 177         struct inode *inode;
 178
 179         if (clp == NULL)
 180                 return;
 181 restart:
 182         spin_lock(&clp->cl_lock);
 183         list_for_each_entry(delegation, &clp->cl_delegations, super_list) {
 184                 if (delegation->inode->i_sb != sb)
 185                         continue;
 186                 inode = igrab(delegation->inode);
 187                 if (inode == NULL)
 188                         continue;
 189                 spin_unlock(&clp->cl_lock);
 190                 nfs_inode_return_delegation(inode);
 191                 iput(inode);
 192                 goto restart;
 193         }
 194         spin_unlock(&clp->cl_lock);
 195 }
 196
 197 /*
 198  * Return all delegations following an NFS4ERR_CB_PATH_DOWN error.
 199  */
 200 void nfs_handle_cb_pathdown(struct nfs4_client *clp)
 201 {
 202         struct nfs_delegation *delegation;
 203         struct inode *inode;
 204
 205         if (clp == NULL)
 206                 return;
 207 restart:
 208         spin_lock(&clp->cl_lock);
 209         list_for_each_entry(delegation, &clp->cl_delegations, super_list) {
 210                 inode = igrab(delegation->inode);
 211                 if (inode == NULL)
 212                         continue;
 213                 spin_unlock(&clp->cl_lock);
 214                 nfs_inode_return_delegation(inode);
 215                 iput(inode);
 216                 goto restart;
 217         }
 218         spin_unlock(&clp->cl_lock);
 219 }
 220
 221 struct recall_threadargs {
 222         struct inode *inode;
 223         struct nfs4_client *clp;
 224         const nfs4_stateid *stateid;
 225
 226         struct completion started;
 227         int result;
 228 };
 229
 230 static int recall_thread(void *data)
 231 {
 232         struct recall_threadargs *args = (struct recall_threadargs *)data;
 233         struct inode *inode = igrab(args->inode);
 234         struct nfs4_client *clp = NFS_SERVER(inode)->nfs4_state;
 235         struct nfs_inode *nfsi = NFS_I(inode);
 236         struct nfs_delegation *delegation;
 237
 238         daemonize("nfsv4-delegreturn");
 239
 240         nfs_msync_inode(inode);
 241         down_read(&clp->cl_sem);
 242         down_write(&nfsi->rwsem);
 243         spin_lock(&clp->cl_lock);
 244         delegation = nfsi->delegation;
 245         if (delegation != NULL && memcmp(delegation->stateid.data,
 246                                 args->stateid->data,
 247                                 sizeof(delegation->stateid.data)) == 0) {
 248                 list_del_init(&delegation->super_list);
 249                 nfsi->delegation = NULL;
 250                 nfsi->delegation_state = 0;
 251                 args->result = 0;
 252         } else {
 253                 delegation = NULL;
 254                 args->result = -ENOENT;
 255         }
 256         spin_unlock(&clp->cl_lock);
 257         complete(&args->started);
 258         nfs_delegation_claim_opens(inode);
 259         up_write(&nfsi->rwsem);
 260         up_read(&clp->cl_sem);
 261         nfs_msync_inode(inode);
 262
 263         if (delegation != NULL)
 264                 nfs_do_return_delegation(inode, delegation);
 265         iput(inode);
 266         module_put_and_exit(0);
 267 }
 268
 269 /*
 270  * Asynchronous delegation recall!
 271  */
 272 int nfs_async_inode_return_delegation(struct inode *inode, const nfs4_stateid *stateid)
 273 {
 274         struct recall_threadargs data = {
 275                 .inode = inode,
 276                 .stateid = stateid,
 277         };
 278         int status;
 279
 280         init_completion(&data.started);
 281         __module_get(THIS_MODULE);
 282         status = kernel_thread(recall_thread, &data, CLONE_KERNEL);
 283         if (status < 0)
 284                 goto out_module_put;
 285         wait_for_completion(&data.started);
 286         return data.result;
 287 out_module_put:
 288         module_put(THIS_MODULE);
 289         return status;
 290 }
 291
 292 /*
 293  * Retrieve the inode associated with a delegation
 294  */
 295 struct inode *nfs_delegation_find_inode(struct nfs4_client *clp, const struct nfs_fh *fhandle)
 296 {
 297         struct nfs_delegation *delegation;
 298         struct inode *res = NULL;
 299         spin_lock(&clp->cl_lock);
 300         list_for_each_entry(delegation, &clp->cl_delegations, super_list) {
 301                 if (nfs_compare_fh(fhandle, &NFS_I(delegation->inode)->fh) == 0) {
 302                         res = igrab(delegation->inode);
 303                         break;
 304                 }
 305         }
 306         spin_unlock(&clp->cl_lock);
 307         return res;
 308 }
 309
 310 /*
 311  * Mark all delegations as needing to be reclaimed
 312  */
 313 void nfs_delegation_mark_reclaim(struct nfs4_client *clp)
 314 {
 315         struct nfs_delegation *delegation;
 316         spin_lock(&clp->cl_lock);
 317         list_for_each_entry(delegation, &clp->cl_delegations, super_list)
 318                 delegation->flags |= NFS_DELEGATION_NEED_RECLAIM;
 319         spin_unlock(&clp->cl_lock);
 320 }
 321
 322 /*
 323  * Reap all unclaimed delegations after reboot recovery is done
 324  */
 325 void nfs_delegation_reap_unclaimed(struct nfs4_client *clp)
 326 {
 327         struct nfs_delegation *delegation, *n;
 328         LIST_HEAD(head);
 329         spin_lock(&clp->cl_lock);
 330         list_for_each_entry_safe(delegation, n, &clp->cl_delegations, super_list) {
 331                 if ((delegation->flags & NFS_DELEGATION_NEED_RECLAIM) == 0)
 332                         continue;
 333                 list_move(&delegation->super_list, &head);
 334                 NFS_I(delegation->inode)->delegation = NULL;
 335                 NFS_I(delegation->inode)->delegation_state = 0;
 336         }
 337         spin_unlock(&clp->cl_lock);
 338         while(!list_empty(&head)) {
 339                 delegation = list_entry(head.next, struct nfs_delegation, super_list);
 340                 list_del(&delegation->super_list);
 341                 nfs_free_delegation(delegation);
 342         }
 343 }