Merge branch 'xen-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/jeremy/xen
[linux-2.6] / 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/completion.h>
10 #include <linux/kthread.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 #include "internal.h"
22
23 static void nfs_do_free_delegation(struct nfs_delegation *delegation)
24 {
25         kfree(delegation);
26 }
27
28 static void nfs_free_delegation_callback(struct rcu_head *head)
29 {
30         struct nfs_delegation *delegation = container_of(head, struct nfs_delegation, rcu);
31
32         nfs_do_free_delegation(delegation);
33 }
34
35 static void nfs_free_delegation(struct nfs_delegation *delegation)
36 {
37         struct rpc_cred *cred;
38
39         cred = rcu_dereference(delegation->cred);
40         rcu_assign_pointer(delegation->cred, NULL);
41         call_rcu(&delegation->rcu, nfs_free_delegation_callback);
42         if (cred)
43                 put_rpccred(cred);
44 }
45
46 static int nfs_delegation_claim_locks(struct nfs_open_context *ctx, struct nfs4_state *state)
47 {
48         struct inode *inode = state->inode;
49         struct file_lock *fl;
50         int status;
51
52         for (fl = inode->i_flock; fl != 0; fl = fl->fl_next) {
53                 if (!(fl->fl_flags & (FL_POSIX|FL_FLOCK)))
54                         continue;
55                 if (nfs_file_open_context(fl->fl_file) != ctx)
56                         continue;
57                 status = nfs4_lock_delegation_recall(state, fl);
58                 if (status >= 0)
59                         continue;
60                 switch (status) {
61                         default:
62                                 printk(KERN_ERR "%s: unhandled error %d.\n",
63                                                 __FUNCTION__, status);
64                         case -NFS4ERR_EXPIRED:
65                                 /* kill_proc(fl->fl_pid, SIGLOST, 1); */
66                         case -NFS4ERR_STALE_CLIENTID:
67                                 nfs4_schedule_state_recovery(NFS_SERVER(inode)->nfs_client);
68                                 goto out_err;
69                 }
70         }
71         return 0;
72 out_err:
73         return status;
74 }
75
76 static void nfs_delegation_claim_opens(struct inode *inode, const nfs4_stateid *stateid)
77 {
78         struct nfs_inode *nfsi = NFS_I(inode);
79         struct nfs_open_context *ctx;
80         struct nfs4_state *state;
81         int err;
82
83 again:
84         spin_lock(&inode->i_lock);
85         list_for_each_entry(ctx, &nfsi->open_files, list) {
86                 state = ctx->state;
87                 if (state == NULL)
88                         continue;
89                 if (!test_bit(NFS_DELEGATED_STATE, &state->flags))
90                         continue;
91                 if (memcmp(state->stateid.data, stateid->data, sizeof(state->stateid.data)) != 0)
92                         continue;
93                 get_nfs_open_context(ctx);
94                 spin_unlock(&inode->i_lock);
95                 err = nfs4_open_delegation_recall(ctx, state, stateid);
96                 if (err >= 0)
97                         err = nfs_delegation_claim_locks(ctx, state);
98                 put_nfs_open_context(ctx);
99                 if (err != 0)
100                         return;
101                 goto again;
102         }
103         spin_unlock(&inode->i_lock);
104 }
105
106 /*
107  * Set up a delegation on an inode
108  */
109 void nfs_inode_reclaim_delegation(struct inode *inode, struct rpc_cred *cred, struct nfs_openres *res)
110 {
111         struct nfs_delegation *delegation = NFS_I(inode)->delegation;
112         struct rpc_cred *oldcred;
113
114         if (delegation == NULL)
115                 return;
116         memcpy(delegation->stateid.data, res->delegation.data,
117                         sizeof(delegation->stateid.data));
118         delegation->type = res->delegation_type;
119         delegation->maxsize = res->maxsize;
120         oldcred = delegation->cred;
121         delegation->cred = get_rpccred(cred);
122         delegation->flags &= ~NFS_DELEGATION_NEED_RECLAIM;
123         NFS_I(inode)->delegation_state = delegation->type;
124         smp_wmb();
125         put_rpccred(oldcred);
126 }
127
128 /*
129  * Set up a delegation on an inode
130  */
131 int nfs_inode_set_delegation(struct inode *inode, struct rpc_cred *cred, struct nfs_openres *res)
132 {
133         struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
134         struct nfs_inode *nfsi = NFS_I(inode);
135         struct nfs_delegation *delegation;
136         int status = 0;
137
138         delegation = kmalloc(sizeof(*delegation), GFP_KERNEL);
139         if (delegation == NULL)
140                 return -ENOMEM;
141         memcpy(delegation->stateid.data, res->delegation.data,
142                         sizeof(delegation->stateid.data));
143         delegation->type = res->delegation_type;
144         delegation->maxsize = res->maxsize;
145         delegation->change_attr = nfsi->change_attr;
146         delegation->cred = get_rpccred(cred);
147         delegation->inode = inode;
148
149         spin_lock(&clp->cl_lock);
150         if (rcu_dereference(nfsi->delegation) == NULL) {
151                 list_add_rcu(&delegation->super_list, &clp->cl_delegations);
152                 nfsi->delegation_state = delegation->type;
153                 rcu_assign_pointer(nfsi->delegation, delegation);
154                 delegation = NULL;
155         } else {
156                 if (memcmp(&delegation->stateid, &nfsi->delegation->stateid,
157                                         sizeof(delegation->stateid)) != 0 ||
158                                 delegation->type != nfsi->delegation->type) {
159                         printk("%s: server %u.%u.%u.%u, handed out a duplicate delegation!\n",
160                                         __FUNCTION__, NIPQUAD(clp->cl_addr.sin_addr));
161                         status = -EIO;
162                 }
163         }
164
165         /* Ensure we revalidate the attributes and page cache! */
166         spin_lock(&inode->i_lock);
167         nfsi->cache_validity |= NFS_INO_REVAL_FORCED;
168         spin_unlock(&inode->i_lock);
169
170         spin_unlock(&clp->cl_lock);
171         kfree(delegation);
172         return status;
173 }
174
175 static int nfs_do_return_delegation(struct inode *inode, struct nfs_delegation *delegation)
176 {
177         int res = 0;
178
179         res = nfs4_proc_delegreturn(inode, delegation->cred, &delegation->stateid);
180         nfs_free_delegation(delegation);
181         return res;
182 }
183
184 /* Sync all data to disk upon delegation return */
185 static void nfs_msync_inode(struct inode *inode)
186 {
187         filemap_fdatawrite(inode->i_mapping);
188         nfs_wb_all(inode);
189         filemap_fdatawait(inode->i_mapping);
190 }
191
192 /*
193  * Basic procedure for returning a delegation to the server
194  */
195 static int __nfs_inode_return_delegation(struct inode *inode, struct nfs_delegation *delegation)
196 {
197         struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
198         struct nfs_inode *nfsi = NFS_I(inode);
199
200         nfs_msync_inode(inode);
201         down_read(&clp->cl_sem);
202         /* Guard against new delegated open calls */
203         down_write(&nfsi->rwsem);
204         nfs_delegation_claim_opens(inode, &delegation->stateid);
205         up_write(&nfsi->rwsem);
206         up_read(&clp->cl_sem);
207         nfs_msync_inode(inode);
208
209         return nfs_do_return_delegation(inode, delegation);
210 }
211
212 static struct nfs_delegation *nfs_detach_delegation_locked(struct nfs_inode *nfsi, const nfs4_stateid *stateid)
213 {
214         struct nfs_delegation *delegation = rcu_dereference(nfsi->delegation);
215
216         if (delegation == NULL)
217                 goto nomatch;
218         if (stateid != NULL && memcmp(delegation->stateid.data, stateid->data,
219                                 sizeof(delegation->stateid.data)) != 0)
220                 goto nomatch;
221         list_del_rcu(&delegation->super_list);
222         nfsi->delegation_state = 0;
223         rcu_assign_pointer(nfsi->delegation, NULL);
224         return delegation;
225 nomatch:
226         return NULL;
227 }
228
229 int nfs_inode_return_delegation(struct inode *inode)
230 {
231         struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
232         struct nfs_inode *nfsi = NFS_I(inode);
233         struct nfs_delegation *delegation;
234         int err = 0;
235
236         if (rcu_dereference(nfsi->delegation) != NULL) {
237                 spin_lock(&clp->cl_lock);
238                 delegation = nfs_detach_delegation_locked(nfsi, NULL);
239                 spin_unlock(&clp->cl_lock);
240                 if (delegation != NULL)
241                         err = __nfs_inode_return_delegation(inode, delegation);
242         }
243         return err;
244 }
245
246 /*
247  * Return all delegations associated to a super block
248  */
249 void nfs_return_all_delegations(struct super_block *sb)
250 {
251         struct nfs_client *clp = NFS_SB(sb)->nfs_client;
252         struct nfs_delegation *delegation;
253         struct inode *inode;
254
255         if (clp == NULL)
256                 return;
257 restart:
258         rcu_read_lock();
259         list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
260                 if (delegation->inode->i_sb != sb)
261                         continue;
262                 inode = igrab(delegation->inode);
263                 if (inode == NULL)
264                         continue;
265                 spin_lock(&clp->cl_lock);
266                 delegation = nfs_detach_delegation_locked(NFS_I(inode), NULL);
267                 spin_unlock(&clp->cl_lock);
268                 rcu_read_unlock();
269                 if (delegation != NULL)
270                         __nfs_inode_return_delegation(inode, delegation);
271                 iput(inode);
272                 goto restart;
273         }
274         rcu_read_unlock();
275 }
276
277 static int nfs_do_expire_all_delegations(void *ptr)
278 {
279         struct nfs_client *clp = ptr;
280         struct nfs_delegation *delegation;
281         struct inode *inode;
282
283         allow_signal(SIGKILL);
284 restart:
285         if (test_bit(NFS4CLNT_STATE_RECOVER, &clp->cl_state) != 0)
286                 goto out;
287         if (test_bit(NFS4CLNT_LEASE_EXPIRED, &clp->cl_state) == 0)
288                 goto out;
289         rcu_read_lock();
290         list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
291                 inode = igrab(delegation->inode);
292                 if (inode == NULL)
293                         continue;
294                 spin_lock(&clp->cl_lock);
295                 delegation = nfs_detach_delegation_locked(NFS_I(inode), NULL);
296                 spin_unlock(&clp->cl_lock);
297                 rcu_read_unlock();
298                 if (delegation)
299                         __nfs_inode_return_delegation(inode, delegation);
300                 iput(inode);
301                 goto restart;
302         }
303         rcu_read_unlock();
304 out:
305         nfs_put_client(clp);
306         module_put_and_exit(0);
307 }
308
309 void nfs_expire_all_delegations(struct nfs_client *clp)
310 {
311         struct task_struct *task;
312
313         __module_get(THIS_MODULE);
314         atomic_inc(&clp->cl_count);
315         task = kthread_run(nfs_do_expire_all_delegations, clp,
316                         "%u.%u.%u.%u-delegreturn",
317                         NIPQUAD(clp->cl_addr.sin_addr));
318         if (!IS_ERR(task))
319                 return;
320         nfs_put_client(clp);
321         module_put(THIS_MODULE);
322 }
323
324 /*
325  * Return all delegations following an NFS4ERR_CB_PATH_DOWN error.
326  */
327 void nfs_handle_cb_pathdown(struct nfs_client *clp)
328 {
329         struct nfs_delegation *delegation;
330         struct inode *inode;
331
332         if (clp == NULL)
333                 return;
334 restart:
335         rcu_read_lock();
336         list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
337                 inode = igrab(delegation->inode);
338                 if (inode == NULL)
339                         continue;
340                 spin_lock(&clp->cl_lock);
341                 delegation = nfs_detach_delegation_locked(NFS_I(inode), NULL);
342                 spin_unlock(&clp->cl_lock);
343                 rcu_read_unlock();
344                 if (delegation != NULL)
345                         __nfs_inode_return_delegation(inode, delegation);
346                 iput(inode);
347                 goto restart;
348         }
349         rcu_read_unlock();
350 }
351
352 struct recall_threadargs {
353         struct inode *inode;
354         struct nfs_client *clp;
355         const nfs4_stateid *stateid;
356
357         struct completion started;
358         int result;
359 };
360
361 static int recall_thread(void *data)
362 {
363         struct recall_threadargs *args = (struct recall_threadargs *)data;
364         struct inode *inode = igrab(args->inode);
365         struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
366         struct nfs_inode *nfsi = NFS_I(inode);
367         struct nfs_delegation *delegation;
368
369         daemonize("nfsv4-delegreturn");
370
371         nfs_msync_inode(inode);
372         down_read(&clp->cl_sem);
373         down_write(&nfsi->rwsem);
374         spin_lock(&clp->cl_lock);
375         delegation = nfs_detach_delegation_locked(nfsi, args->stateid);
376         if (delegation != NULL)
377                 args->result = 0;
378         else
379                 args->result = -ENOENT;
380         spin_unlock(&clp->cl_lock);
381         complete(&args->started);
382         nfs_delegation_claim_opens(inode, args->stateid);
383         up_write(&nfsi->rwsem);
384         up_read(&clp->cl_sem);
385         nfs_msync_inode(inode);
386
387         if (delegation != NULL)
388                 nfs_do_return_delegation(inode, delegation);
389         iput(inode);
390         module_put_and_exit(0);
391 }
392
393 /*
394  * Asynchronous delegation recall!
395  */
396 int nfs_async_inode_return_delegation(struct inode *inode, const nfs4_stateid *stateid)
397 {
398         struct recall_threadargs data = {
399                 .inode = inode,
400                 .stateid = stateid,
401         };
402         int status;
403
404         init_completion(&data.started);
405         __module_get(THIS_MODULE);
406         status = kernel_thread(recall_thread, &data, CLONE_KERNEL);
407         if (status < 0)
408                 goto out_module_put;
409         wait_for_completion(&data.started);
410         return data.result;
411 out_module_put:
412         module_put(THIS_MODULE);
413         return status;
414 }
415
416 /*
417  * Retrieve the inode associated with a delegation
418  */
419 struct inode *nfs_delegation_find_inode(struct nfs_client *clp, const struct nfs_fh *fhandle)
420 {
421         struct nfs_delegation *delegation;
422         struct inode *res = NULL;
423         rcu_read_lock();
424         list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
425                 if (nfs_compare_fh(fhandle, &NFS_I(delegation->inode)->fh) == 0) {
426                         res = igrab(delegation->inode);
427                         break;
428                 }
429         }
430         rcu_read_unlock();
431         return res;
432 }
433
434 /*
435  * Mark all delegations as needing to be reclaimed
436  */
437 void nfs_delegation_mark_reclaim(struct nfs_client *clp)
438 {
439         struct nfs_delegation *delegation;
440         rcu_read_lock();
441         list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list)
442                 delegation->flags |= NFS_DELEGATION_NEED_RECLAIM;
443         rcu_read_unlock();
444 }
445
446 /*
447  * Reap all unclaimed delegations after reboot recovery is done
448  */
449 void nfs_delegation_reap_unclaimed(struct nfs_client *clp)
450 {
451         struct nfs_delegation *delegation;
452 restart:
453         rcu_read_lock();
454         list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
455                 if ((delegation->flags & NFS_DELEGATION_NEED_RECLAIM) == 0)
456                         continue;
457                 spin_lock(&clp->cl_lock);
458                 delegation = nfs_detach_delegation_locked(NFS_I(delegation->inode), NULL);
459                 spin_unlock(&clp->cl_lock);
460                 rcu_read_unlock();
461                 if (delegation != NULL)
462                         nfs_free_delegation(delegation);
463                 goto restart;
464         }
465         rcu_read_unlock();
466 }
467
468 int nfs4_copy_delegation_stateid(nfs4_stateid *dst, struct inode *inode)
469 {
470         struct nfs_inode *nfsi = NFS_I(inode);
471         struct nfs_delegation *delegation;
472         int ret = 0;
473
474         rcu_read_lock();
475         delegation = rcu_dereference(nfsi->delegation);
476         if (delegation != NULL) {
477                 memcpy(dst->data, delegation->stateid.data, sizeof(dst->data));
478                 ret = 1;
479         }
480         rcu_read_unlock();
481         return ret;
482 }