Merge master.kernel.org:/pub/scm/linux/kernel/git/bunk/trivial
[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/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 int nfs_delegation_claim_locks(struct nfs_open_context *ctx, struct nfs4_state *state)
35 {
36         struct inode *inode = state->inode;
37         struct file_lock *fl;
38         int status;
39
40         for (fl = inode->i_flock; fl != 0; fl = fl->fl_next) {
41                 if (!(fl->fl_flags & (FL_POSIX|FL_FLOCK)))
42                         continue;
43                 if ((struct nfs_open_context *)fl->fl_file->private_data != ctx)
44                         continue;
45                 status = nfs4_lock_delegation_recall(state, fl);
46                 if (status >= 0)
47                         continue;
48                 switch (status) {
49                         default:
50                                 printk(KERN_ERR "%s: unhandled error %d.\n",
51                                                 __FUNCTION__, status);
52                         case -NFS4ERR_EXPIRED:
53                                 /* kill_proc(fl->fl_pid, SIGLOST, 1); */
54                         case -NFS4ERR_STALE_CLIENTID:
55                                 nfs4_schedule_state_recovery(NFS_SERVER(inode)->nfs4_state);
56                                 goto out_err;
57                 }
58         }
59         return 0;
60 out_err:
61         return status;
62 }
63
64 static void nfs_delegation_claim_opens(struct inode *inode)
65 {
66         struct nfs_inode *nfsi = NFS_I(inode);
67         struct nfs_open_context *ctx;
68         struct nfs4_state *state;
69         int err;
70
71 again:
72         spin_lock(&inode->i_lock);
73         list_for_each_entry(ctx, &nfsi->open_files, list) {
74                 state = ctx->state;
75                 if (state == NULL)
76                         continue;
77                 if (!test_bit(NFS_DELEGATED_STATE, &state->flags))
78                         continue;
79                 get_nfs_open_context(ctx);
80                 spin_unlock(&inode->i_lock);
81                 err = nfs4_open_delegation_recall(ctx->dentry, state);
82                 if (err >= 0)
83                         err = nfs_delegation_claim_locks(ctx, state);
84                 put_nfs_open_context(ctx);
85                 if (err != 0)
86                         return;
87                 goto again;
88         }
89         spin_unlock(&inode->i_lock);
90 }
91
92 /*
93  * Set up a delegation on an inode
94  */
95 void nfs_inode_reclaim_delegation(struct inode *inode, struct rpc_cred *cred, struct nfs_openres *res)
96 {
97         struct nfs_delegation *delegation = NFS_I(inode)->delegation;
98
99         if (delegation == NULL)
100                 return;
101         memcpy(delegation->stateid.data, res->delegation.data,
102                         sizeof(delegation->stateid.data));
103         delegation->type = res->delegation_type;
104         delegation->maxsize = res->maxsize;
105         put_rpccred(cred);
106         delegation->cred = get_rpccred(cred);
107         delegation->flags &= ~NFS_DELEGATION_NEED_RECLAIM;
108         NFS_I(inode)->delegation_state = delegation->type;
109         smp_wmb();
110 }
111
112 /*
113  * Set up a delegation on an inode
114  */
115 int nfs_inode_set_delegation(struct inode *inode, struct rpc_cred *cred, struct nfs_openres *res)
116 {
117         struct nfs4_client *clp = NFS_SERVER(inode)->nfs4_state;
118         struct nfs_inode *nfsi = NFS_I(inode);
119         struct nfs_delegation *delegation;
120         int status = 0;
121
122         /* Ensure we first revalidate the attributes and page cache! */
123         if ((nfsi->cache_validity & (NFS_INO_REVAL_PAGECACHE|NFS_INO_INVALID_ATTR)))
124                 __nfs_revalidate_inode(NFS_SERVER(inode), inode);
125
126         delegation = nfs_alloc_delegation();
127         if (delegation == NULL)
128                 return -ENOMEM;
129         memcpy(delegation->stateid.data, res->delegation.data,
130                         sizeof(delegation->stateid.data));
131         delegation->type = res->delegation_type;
132         delegation->maxsize = res->maxsize;
133         delegation->cred = get_rpccred(cred);
134         delegation->inode = inode;
135
136         spin_lock(&clp->cl_lock);
137         if (nfsi->delegation == NULL) {
138                 list_add(&delegation->super_list, &clp->cl_delegations);
139                 nfsi->delegation = delegation;
140                 nfsi->delegation_state = delegation->type;
141                 delegation = NULL;
142         } else {
143                 if (memcmp(&delegation->stateid, &nfsi->delegation->stateid,
144                                         sizeof(delegation->stateid)) != 0 ||
145                                 delegation->type != nfsi->delegation->type) {
146                         printk("%s: server %u.%u.%u.%u, handed out a duplicate delegation!\n",
147                                         __FUNCTION__, NIPQUAD(clp->cl_addr));
148                         status = -EIO;
149                 }
150         }
151         spin_unlock(&clp->cl_lock);
152         kfree(delegation);
153         return status;
154 }
155
156 static int nfs_do_return_delegation(struct inode *inode, struct nfs_delegation *delegation)
157 {
158         int res = 0;
159
160         __nfs_revalidate_inode(NFS_SERVER(inode), inode);
161
162         res = nfs4_proc_delegreturn(inode, delegation->cred, &delegation->stateid);
163         nfs_free_delegation(delegation);
164         return res;
165 }
166
167 /* Sync all data to disk upon delegation return */
168 static void nfs_msync_inode(struct inode *inode)
169 {
170         filemap_fdatawrite(inode->i_mapping);
171         nfs_wb_all(inode);
172         filemap_fdatawait(inode->i_mapping);
173 }
174
175 /*
176  * Basic procedure for returning a delegation to the server
177  */
178 int __nfs_inode_return_delegation(struct inode *inode)
179 {
180         struct nfs4_client *clp = NFS_SERVER(inode)->nfs4_state;
181         struct nfs_inode *nfsi = NFS_I(inode);
182         struct nfs_delegation *delegation;
183         int res = 0;
184
185         nfs_msync_inode(inode);
186         down_read(&clp->cl_sem);
187         /* Guard against new delegated open calls */
188         down_write(&nfsi->rwsem);
189         spin_lock(&clp->cl_lock);
190         delegation = nfsi->delegation;
191         if (delegation != NULL) {
192                 list_del_init(&delegation->super_list);
193                 nfsi->delegation = NULL;
194                 nfsi->delegation_state = 0;
195         }
196         spin_unlock(&clp->cl_lock);
197         nfs_delegation_claim_opens(inode);
198         up_write(&nfsi->rwsem);
199         up_read(&clp->cl_sem);
200         nfs_msync_inode(inode);
201
202         if (delegation != NULL)
203                 res = nfs_do_return_delegation(inode, delegation);
204         return res;
205 }
206
207 /*
208  * Return all delegations associated to a super block
209  */
210 void nfs_return_all_delegations(struct super_block *sb)
211 {
212         struct nfs4_client *clp = NFS_SB(sb)->nfs4_state;
213         struct nfs_delegation *delegation;
214         struct inode *inode;
215
216         if (clp == NULL)
217                 return;
218 restart:
219         spin_lock(&clp->cl_lock);
220         list_for_each_entry(delegation, &clp->cl_delegations, super_list) {
221                 if (delegation->inode->i_sb != sb)
222                         continue;
223                 inode = igrab(delegation->inode);
224                 if (inode == NULL)
225                         continue;
226                 spin_unlock(&clp->cl_lock);
227                 nfs_inode_return_delegation(inode);
228                 iput(inode);
229                 goto restart;
230         }
231         spin_unlock(&clp->cl_lock);
232 }
233
234 /*
235  * Return all delegations following an NFS4ERR_CB_PATH_DOWN error.
236  */
237 void nfs_handle_cb_pathdown(struct nfs4_client *clp)
238 {
239         struct nfs_delegation *delegation;
240         struct inode *inode;
241
242         if (clp == NULL)
243                 return;
244 restart:
245         spin_lock(&clp->cl_lock);
246         list_for_each_entry(delegation, &clp->cl_delegations, super_list) {
247                 inode = igrab(delegation->inode);
248                 if (inode == NULL)
249                         continue;
250                 spin_unlock(&clp->cl_lock);
251                 nfs_inode_return_delegation(inode);
252                 iput(inode);
253                 goto restart;
254         }
255         spin_unlock(&clp->cl_lock);
256 }
257
258 struct recall_threadargs {
259         struct inode *inode;
260         struct nfs4_client *clp;
261         const nfs4_stateid *stateid;
262
263         struct completion started;
264         int result;
265 };
266
267 static int recall_thread(void *data)
268 {
269         struct recall_threadargs *args = (struct recall_threadargs *)data;
270         struct inode *inode = igrab(args->inode);
271         struct nfs4_client *clp = NFS_SERVER(inode)->nfs4_state;
272         struct nfs_inode *nfsi = NFS_I(inode);
273         struct nfs_delegation *delegation;
274
275         daemonize("nfsv4-delegreturn");
276
277         nfs_msync_inode(inode);
278         down_read(&clp->cl_sem);
279         down_write(&nfsi->rwsem);
280         spin_lock(&clp->cl_lock);
281         delegation = nfsi->delegation;
282         if (delegation != NULL && memcmp(delegation->stateid.data,
283                                 args->stateid->data,
284                                 sizeof(delegation->stateid.data)) == 0) {
285                 list_del_init(&delegation->super_list);
286                 nfsi->delegation = NULL;
287                 nfsi->delegation_state = 0;
288                 args->result = 0;
289         } else {
290                 delegation = NULL;
291                 args->result = -ENOENT;
292         }
293         spin_unlock(&clp->cl_lock);
294         complete(&args->started);
295         nfs_delegation_claim_opens(inode);
296         up_write(&nfsi->rwsem);
297         up_read(&clp->cl_sem);
298         nfs_msync_inode(inode);
299
300         if (delegation != NULL)
301                 nfs_do_return_delegation(inode, delegation);
302         iput(inode);
303         module_put_and_exit(0);
304 }
305
306 /*
307  * Asynchronous delegation recall!
308  */
309 int nfs_async_inode_return_delegation(struct inode *inode, const nfs4_stateid *stateid)
310 {
311         struct recall_threadargs data = {
312                 .inode = inode,
313                 .stateid = stateid,
314         };
315         int status;
316
317         init_completion(&data.started);
318         __module_get(THIS_MODULE);
319         status = kernel_thread(recall_thread, &data, CLONE_KERNEL);
320         if (status < 0)
321                 goto out_module_put;
322         wait_for_completion(&data.started);
323         return data.result;
324 out_module_put:
325         module_put(THIS_MODULE);
326         return status;
327 }
328
329 /*
330  * Retrieve the inode associated with a delegation
331  */
332 struct inode *nfs_delegation_find_inode(struct nfs4_client *clp, const struct nfs_fh *fhandle)
333 {
334         struct nfs_delegation *delegation;
335         struct inode *res = NULL;
336         spin_lock(&clp->cl_lock);
337         list_for_each_entry(delegation, &clp->cl_delegations, super_list) {
338                 if (nfs_compare_fh(fhandle, &NFS_I(delegation->inode)->fh) == 0) {
339                         res = igrab(delegation->inode);
340                         break;
341                 }
342         }
343         spin_unlock(&clp->cl_lock);
344         return res;
345 }
346
347 /*
348  * Mark all delegations as needing to be reclaimed
349  */
350 void nfs_delegation_mark_reclaim(struct nfs4_client *clp)
351 {
352         struct nfs_delegation *delegation;
353         spin_lock(&clp->cl_lock);
354         list_for_each_entry(delegation, &clp->cl_delegations, super_list)
355                 delegation->flags |= NFS_DELEGATION_NEED_RECLAIM;
356         spin_unlock(&clp->cl_lock);
357 }
358
359 /*
360  * Reap all unclaimed delegations after reboot recovery is done
361  */
362 void nfs_delegation_reap_unclaimed(struct nfs4_client *clp)
363 {
364         struct nfs_delegation *delegation, *n;
365         LIST_HEAD(head);
366         spin_lock(&clp->cl_lock);
367         list_for_each_entry_safe(delegation, n, &clp->cl_delegations, super_list) {
368                 if ((delegation->flags & NFS_DELEGATION_NEED_RECLAIM) == 0)
369                         continue;
370                 list_move(&delegation->super_list, &head);
371                 NFS_I(delegation->inode)->delegation = NULL;
372                 NFS_I(delegation->inode)->delegation_state = 0;
373         }
374         spin_unlock(&clp->cl_lock);
375         while(!list_empty(&head)) {
376                 delegation = list_entry(head.next, struct nfs_delegation, super_list);
377                 list_del(&delegation->super_list);
378                 nfs_free_delegation(delegation);
379         }
380 }