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   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         /* Ensure we first revalidate the attributes and page cache! */
  89         if ((nfsi->cache_validity & (NFS_INO_REVAL_PAGECACHE|NFS_INO_INVALID_ATTR)))
  90                 __nfs_revalidate_inode(NFS_SERVER(inode), inode);
  91
  92         delegation = nfs_alloc_delegation();
  93         if (delegation == NULL)
  94                 return -ENOMEM;
  95         memcpy(delegation->stateid.data, res->delegation.data,
  96                         sizeof(delegation->stateid.data));
  97         delegation->type = res->delegation_type;
  98         delegation->maxsize = res->maxsize;
  99         delegation->cred = get_rpccred(cred);
 100         delegation->inode = inode;
 101
 102         spin_lock(&clp->cl_lock);
 103         if (nfsi->delegation == NULL) {
 104                 list_add(&delegation->super_list, &clp->cl_delegations);
 105                 nfsi->delegation = delegation;
 106                 nfsi->delegation_state = delegation->type;
 107                 delegation = NULL;
 108         } else {
 109                 if (memcmp(&delegation->stateid, &nfsi->delegation->stateid,
 110                                         sizeof(delegation->stateid)) != 0 ||
 111                                 delegation->type != nfsi->delegation->type) {
 112                         printk("%s: server %u.%u.%u.%u, handed out a duplicate delegation!\n",
 113                                         __FUNCTION__, NIPQUAD(clp->cl_addr));
 114                         status = -EIO;
 115                 }
 116         }
 117         spin_unlock(&clp->cl_lock);
 118         if (delegation != NULL)
 119                 kfree(delegation);
 120         return status;
 121 }
 122
 123 static int nfs_do_return_delegation(struct inode *inode, struct nfs_delegation *delegation)
 124 {
 125         int res = 0;
 126
 127         __nfs_revalidate_inode(NFS_SERVER(inode), inode);
 128
 129         res = nfs4_proc_delegreturn(inode, delegation->cred, &delegation->stateid);
 130         nfs_free_delegation(delegation);
 131         return res;
 132 }
 133
 134 /* Sync all data to disk upon delegation return */
 135 static void nfs_msync_inode(struct inode *inode)
 136 {
 137         filemap_fdatawrite(inode->i_mapping);
 138         nfs_wb_all(inode);
 139         filemap_fdatawait(inode->i_mapping);
 140 }
 141
 142 /*
 143  * Basic procedure for returning a delegation to the server
 144  */
 145 int __nfs_inode_return_delegation(struct inode *inode)
 146 {
 147         struct nfs4_client *clp = NFS_SERVER(inode)->nfs4_state;
 148         struct nfs_inode *nfsi = NFS_I(inode);
 149         struct nfs_delegation *delegation;
 150         int res = 0;
 151
 152         nfs_msync_inode(inode);
 153         down_read(&clp->cl_sem);
 154         /* Guard against new delegated open calls */
 155         down_write(&nfsi->rwsem);
 156         spin_lock(&clp->cl_lock);
 157         delegation = nfsi->delegation;
 158         if (delegation != NULL) {
 159                 list_del_init(&delegation->super_list);
 160                 nfsi->delegation = NULL;
 161                 nfsi->delegation_state = 0;
 162         }
 163         spin_unlock(&clp->cl_lock);
 164         nfs_delegation_claim_opens(inode);
 165         up_write(&nfsi->rwsem);
 166         up_read(&clp->cl_sem);
 167         nfs_msync_inode(inode);
 168
 169         if (delegation != NULL)
 170                 res = nfs_do_return_delegation(inode, delegation);
 171         return res;
 172 }
 173
 174 /*
 175  * Return all delegations associated to a super block
 176  */
 177 void nfs_return_all_delegations(struct super_block *sb)
 178 {
 179         struct nfs4_client *clp = NFS_SB(sb)->nfs4_state;
 180         struct nfs_delegation *delegation;
 181         struct inode *inode;
 182
 183         if (clp == NULL)
 184                 return;
 185 restart:
 186         spin_lock(&clp->cl_lock);
 187         list_for_each_entry(delegation, &clp->cl_delegations, super_list) {
 188                 if (delegation->inode->i_sb != sb)
 189                         continue;
 190                 inode = igrab(delegation->inode);
 191                 if (inode == NULL)
 192                         continue;
 193                 spin_unlock(&clp->cl_lock);
 194                 nfs_inode_return_delegation(inode);
 195                 iput(inode);
 196                 goto restart;
 197         }
 198         spin_unlock(&clp->cl_lock);
 199 }
 200
 201 /*
 202  * Return all delegations following an NFS4ERR_CB_PATH_DOWN error.
 203  */
 204 void nfs_handle_cb_pathdown(struct nfs4_client *clp)
 205 {
 206         struct nfs_delegation *delegation;
 207         struct inode *inode;
 208
 209         if (clp == NULL)
 210                 return;
 211 restart:
 212         spin_lock(&clp->cl_lock);
 213         list_for_each_entry(delegation, &clp->cl_delegations, super_list) {
 214                 inode = igrab(delegation->inode);
 215                 if (inode == NULL)
 216                         continue;
 217                 spin_unlock(&clp->cl_lock);
 218                 nfs_inode_return_delegation(inode);
 219                 iput(inode);
 220                 goto restart;
 221         }
 222         spin_unlock(&clp->cl_lock);
 223 }
 224
 225 struct recall_threadargs {
 226         struct inode *inode;
 227         struct nfs4_client *clp;
 228         const nfs4_stateid *stateid;
 229
 230         struct completion started;
 231         int result;
 232 };
 233
 234 static int recall_thread(void *data)
 235 {
 236         struct recall_threadargs *args = (struct recall_threadargs *)data;
 237         struct inode *inode = igrab(args->inode);
 238         struct nfs4_client *clp = NFS_SERVER(inode)->nfs4_state;
 239         struct nfs_inode *nfsi = NFS_I(inode);
 240         struct nfs_delegation *delegation;
 241
 242         daemonize("nfsv4-delegreturn");
 243
 244         nfs_msync_inode(inode);
 245         down_read(&clp->cl_sem);
 246         down_write(&nfsi->rwsem);
 247         spin_lock(&clp->cl_lock);
 248         delegation = nfsi->delegation;
 249         if (delegation != NULL && memcmp(delegation->stateid.data,
 250                                 args->stateid->data,
 251                                 sizeof(delegation->stateid.data)) == 0) {
 252                 list_del_init(&delegation->super_list);
 253                 nfsi->delegation = NULL;
 254                 nfsi->delegation_state = 0;
 255                 args->result = 0;
 256         } else {
 257                 delegation = NULL;
 258                 args->result = -ENOENT;
 259         }
 260         spin_unlock(&clp->cl_lock);
 261         complete(&args->started);
 262         nfs_delegation_claim_opens(inode);
 263         up_write(&nfsi->rwsem);
 264         up_read(&clp->cl_sem);
 265         nfs_msync_inode(inode);
 266
 267         if (delegation != NULL)
 268                 nfs_do_return_delegation(inode, delegation);
 269         iput(inode);
 270         module_put_and_exit(0);
 271 }
 272
 273 /*
 274  * Asynchronous delegation recall!
 275  */
 276 int nfs_async_inode_return_delegation(struct inode *inode, const nfs4_stateid *stateid)
 277 {
 278         struct recall_threadargs data = {
 279                 .inode = inode,
 280                 .stateid = stateid,
 281         };
 282         int status;
 283
 284         init_completion(&data.started);
 285         __module_get(THIS_MODULE);
 286         status = kernel_thread(recall_thread, &data, CLONE_KERNEL);
 287         if (status < 0)
 288                 goto out_module_put;
 289         wait_for_completion(&data.started);
 290         return data.result;
 291 out_module_put:
 292         module_put(THIS_MODULE);
 293         return status;
 294 }
 295
 296 /*
 297  * Retrieve the inode associated with a delegation
 298  */
 299 struct inode *nfs_delegation_find_inode(struct nfs4_client *clp, const struct nfs_fh *fhandle)
 300 {
 301         struct nfs_delegation *delegation;
 302         struct inode *res = NULL;
 303         spin_lock(&clp->cl_lock);
 304         list_for_each_entry(delegation, &clp->cl_delegations, super_list) {
 305                 if (nfs_compare_fh(fhandle, &NFS_I(delegation->inode)->fh) == 0) {
 306                         res = igrab(delegation->inode);
 307                         break;
 308                 }
 309         }
 310         spin_unlock(&clp->cl_lock);
 311         return res;
 312 }
 313
 314 /*
 315  * Mark all delegations as needing to be reclaimed
 316  */
 317 void nfs_delegation_mark_reclaim(struct nfs4_client *clp)
 318 {
 319         struct nfs_delegation *delegation;
 320         spin_lock(&clp->cl_lock);
 321         list_for_each_entry(delegation, &clp->cl_delegations, super_list)
 322                 delegation->flags |= NFS_DELEGATION_NEED_RECLAIM;
 323         spin_unlock(&clp->cl_lock);
 324 }
 325
 326 /*
 327  * Reap all unclaimed delegations after reboot recovery is done
 328  */
 329 void nfs_delegation_reap_unclaimed(struct nfs4_client *clp)
 330 {
 331         struct nfs_delegation *delegation, *n;
 332         LIST_HEAD(head);
 333         spin_lock(&clp->cl_lock);
 334         list_for_each_entry_safe(delegation, n, &clp->cl_delegations, super_list) {
 335                 if ((delegation->flags & NFS_DELEGATION_NEED_RECLAIM) == 0)
 336                         continue;
 337                 list_move(&delegation->super_list, &head);
 338                 NFS_I(delegation->inode)->delegation = NULL;
 339                 NFS_I(delegation->inode)->delegation_state = 0;
 340         }
 341         spin_unlock(&clp->cl_lock);
 342         while(!list_empty(&head)) {
 343                 delegation = list_entry(head.next, struct nfs_delegation, super_list);
 344                 list_del(&delegation->super_list);
 345                 nfs_free_delegation(delegation);
 346         }
 347 }