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