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Linux/fs/nfs/pnfs_dev.c

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  1 /*
  2  *  Device operations for the pnfs client.
  3  *
  4  *  Copyright (c) 2002
  5  *  The Regents of the University of Michigan
  6  *  All Rights Reserved
  7  *
  8  *  Dean Hildebrand <dhildebz@umich.edu>
  9  *  Garth Goodson   <Garth.Goodson@netapp.com>
 10  *
 11  *  Permission is granted to use, copy, create derivative works, and
 12  *  redistribute this software and such derivative works for any purpose,
 13  *  so long as the name of the University of Michigan is not used in
 14  *  any advertising or publicity pertaining to the use or distribution
 15  *  of this software without specific, written prior authorization. If
 16  *  the above copyright notice or any other identification of the
 17  *  University of Michigan is included in any copy of any portion of
 18  *  this software, then the disclaimer below must also be included.
 19  *
 20  *  This software is provided as is, without representation or warranty
 21  *  of any kind either express or implied, including without limitation
 22  *  the implied warranties of merchantability, fitness for a particular
 23  *  purpose, or noninfringement.  The Regents of the University of
 24  *  Michigan shall not be liable for any damages, including special,
 25  *  indirect, incidental, or consequential damages, with respect to any
 26  *  claim arising out of or in connection with the use of the software,
 27  *  even if it has been or is hereafter advised of the possibility of
 28  *  such damages.
 29  */
 30 
 31 #include <linux/export.h>
 32 #include <linux/nfs_fs.h>
 33 #include "nfs4session.h"
 34 #include "internal.h"
 35 #include "pnfs.h"
 36 
 37 #define NFSDBG_FACILITY         NFSDBG_PNFS
 38 
 39 /*
 40  * Device ID RCU cache. A device ID is unique per server and layout type.
 41  */
 42 #define NFS4_DEVICE_ID_HASH_BITS        5
 43 #define NFS4_DEVICE_ID_HASH_SIZE        (1 << NFS4_DEVICE_ID_HASH_BITS)
 44 #define NFS4_DEVICE_ID_HASH_MASK        (NFS4_DEVICE_ID_HASH_SIZE - 1)
 45 
 46 
 47 static struct hlist_head nfs4_deviceid_cache[NFS4_DEVICE_ID_HASH_SIZE];
 48 static DEFINE_SPINLOCK(nfs4_deviceid_lock);
 49 
 50 #ifdef NFS_DEBUG
 51 void
 52 nfs4_print_deviceid(const struct nfs4_deviceid *id)
 53 {
 54         u32 *p = (u32 *)id;
 55 
 56         dprintk("%s: device id= [%x%x%x%x]\n", __func__,
 57                 p[0], p[1], p[2], p[3]);
 58 }
 59 EXPORT_SYMBOL_GPL(nfs4_print_deviceid);
 60 #endif
 61 
 62 static inline u32
 63 nfs4_deviceid_hash(const struct nfs4_deviceid *id)
 64 {
 65         unsigned char *cptr = (unsigned char *)id->data;
 66         unsigned int nbytes = NFS4_DEVICEID4_SIZE;
 67         u32 x = 0;
 68 
 69         while (nbytes--) {
 70                 x *= 37;
 71                 x += *cptr++;
 72         }
 73         return x & NFS4_DEVICE_ID_HASH_MASK;
 74 }
 75 
 76 static struct nfs4_deviceid_node *
 77 _lookup_deviceid(const struct pnfs_layoutdriver_type *ld,
 78                  const struct nfs_client *clp, const struct nfs4_deviceid *id,
 79                  long hash)
 80 {
 81         struct nfs4_deviceid_node *d;
 82 
 83         hlist_for_each_entry_rcu(d, &nfs4_deviceid_cache[hash], node)
 84                 if (d->ld == ld && d->nfs_client == clp &&
 85                     !memcmp(&d->deviceid, id, sizeof(*id))) {
 86                         if (atomic_read(&d->ref))
 87                                 return d;
 88                         else
 89                                 continue;
 90                 }
 91         return NULL;
 92 }
 93 
 94 static struct nfs4_deviceid_node *
 95 nfs4_get_device_info(struct nfs_server *server,
 96                 const struct nfs4_deviceid *dev_id,
 97                 struct rpc_cred *cred, gfp_t gfp_flags)
 98 {
 99         struct nfs4_deviceid_node *d = NULL;
100         struct pnfs_device *pdev = NULL;
101         struct page **pages = NULL;
102         u32 max_resp_sz;
103         int max_pages;
104         int rc, i;
105 
106         /*
107          * Use the session max response size as the basis for setting
108          * GETDEVICEINFO's maxcount
109          */
110         max_resp_sz = server->nfs_client->cl_session->fc_attrs.max_resp_sz;
111         if (server->pnfs_curr_ld->max_deviceinfo_size &&
112             server->pnfs_curr_ld->max_deviceinfo_size < max_resp_sz)
113                 max_resp_sz = server->pnfs_curr_ld->max_deviceinfo_size;
114         max_pages = nfs_page_array_len(0, max_resp_sz);
115         dprintk("%s: server %p max_resp_sz %u max_pages %d\n",
116                 __func__, server, max_resp_sz, max_pages);
117 
118         pdev = kzalloc(sizeof(*pdev), gfp_flags);
119         if (!pdev)
120                 return NULL;
121 
122         pages = kcalloc(max_pages, sizeof(struct page *), gfp_flags);
123         if (!pages)
124                 goto out_free_pdev;
125 
126         for (i = 0; i < max_pages; i++) {
127                 pages[i] = alloc_page(gfp_flags);
128                 if (!pages[i])
129                         goto out_free_pages;
130         }
131 
132         memcpy(&pdev->dev_id, dev_id, sizeof(*dev_id));
133         pdev->layout_type = server->pnfs_curr_ld->id;
134         pdev->pages = pages;
135         pdev->pgbase = 0;
136         pdev->pglen = max_resp_sz;
137         pdev->mincount = 0;
138         pdev->maxcount = max_resp_sz - nfs41_maxgetdevinfo_overhead;
139 
140         rc = nfs4_proc_getdeviceinfo(server, pdev, cred);
141         dprintk("%s getdevice info returns %d\n", __func__, rc);
142         if (rc)
143                 goto out_free_pages;
144 
145         /*
146          * Found new device, need to decode it and then add it to the
147          * list of known devices for this mountpoint.
148          */
149         d = server->pnfs_curr_ld->alloc_deviceid_node(server, pdev,
150                         gfp_flags);
151         if (d && pdev->nocache)
152                 set_bit(NFS_DEVICEID_NOCACHE, &d->flags);
153 
154 out_free_pages:
155         for (i = 0; i < max_pages; i++)
156                 __free_page(pages[i]);
157         kfree(pages);
158 out_free_pdev:
159         kfree(pdev);
160         dprintk("<-- %s d %p\n", __func__, d);
161         return d;
162 }
163 
164 /*
165  * Lookup a deviceid in cache and get a reference count on it if found
166  *
167  * @clp nfs_client associated with deviceid
168  * @id deviceid to look up
169  */
170 static struct nfs4_deviceid_node *
171 __nfs4_find_get_deviceid(struct nfs_server *server,
172                 const struct nfs4_deviceid *id, long hash)
173 {
174         struct nfs4_deviceid_node *d;
175 
176         rcu_read_lock();
177         d = _lookup_deviceid(server->pnfs_curr_ld, server->nfs_client, id,
178                         hash);
179         if (d != NULL && !atomic_inc_not_zero(&d->ref))
180                 d = NULL;
181         rcu_read_unlock();
182         return d;
183 }
184 
185 struct nfs4_deviceid_node *
186 nfs4_find_get_deviceid(struct nfs_server *server,
187                 const struct nfs4_deviceid *id, struct rpc_cred *cred,
188                 gfp_t gfp_mask)
189 {
190         long hash = nfs4_deviceid_hash(id);
191         struct nfs4_deviceid_node *d, *new;
192 
193         d = __nfs4_find_get_deviceid(server, id, hash);
194         if (d)
195                 return d;
196 
197         new = nfs4_get_device_info(server, id, cred, gfp_mask);
198         if (!new)
199                 return new;
200 
201         spin_lock(&nfs4_deviceid_lock);
202         d = __nfs4_find_get_deviceid(server, id, hash);
203         if (d) {
204                 spin_unlock(&nfs4_deviceid_lock);
205                 server->pnfs_curr_ld->free_deviceid_node(new);
206                 return d;
207         }
208         hlist_add_head_rcu(&new->node, &nfs4_deviceid_cache[hash]);
209         atomic_inc(&new->ref);
210         spin_unlock(&nfs4_deviceid_lock);
211 
212         return new;
213 }
214 EXPORT_SYMBOL_GPL(nfs4_find_get_deviceid);
215 
216 /*
217  * Remove a deviceid from cache
218  *
219  * @clp nfs_client associated with deviceid
220  * @id the deviceid to unhash
221  *
222  * @ret the unhashed node, if found and dereferenced to zero, NULL otherwise.
223  */
224 void
225 nfs4_delete_deviceid(const struct pnfs_layoutdriver_type *ld,
226                          const struct nfs_client *clp, const struct nfs4_deviceid *id)
227 {
228         struct nfs4_deviceid_node *d;
229 
230         spin_lock(&nfs4_deviceid_lock);
231         rcu_read_lock();
232         d = _lookup_deviceid(ld, clp, id, nfs4_deviceid_hash(id));
233         rcu_read_unlock();
234         if (!d) {
235                 spin_unlock(&nfs4_deviceid_lock);
236                 return;
237         }
238         hlist_del_init_rcu(&d->node);
239         clear_bit(NFS_DEVICEID_NOCACHE, &d->flags);
240         spin_unlock(&nfs4_deviceid_lock);
241 
242         /* balance the initial ref set in pnfs_insert_deviceid */
243         nfs4_put_deviceid_node(d);
244 }
245 EXPORT_SYMBOL_GPL(nfs4_delete_deviceid);
246 
247 void
248 nfs4_init_deviceid_node(struct nfs4_deviceid_node *d, struct nfs_server *server,
249                         const struct nfs4_deviceid *id)
250 {
251         INIT_HLIST_NODE(&d->node);
252         INIT_HLIST_NODE(&d->tmpnode);
253         d->ld = server->pnfs_curr_ld;
254         d->nfs_client = server->nfs_client;
255         d->flags = 0;
256         d->deviceid = *id;
257         atomic_set(&d->ref, 1);
258 }
259 EXPORT_SYMBOL_GPL(nfs4_init_deviceid_node);
260 
261 /*
262  * Dereference a deviceid node and delete it when its reference count drops
263  * to zero.
264  *
265  * @d deviceid node to put
266  *
267  * return true iff the node was deleted
268  * Note that since the test for d->ref == 0 is sufficient to establish
269  * that the node is no longer hashed in the global device id cache.
270  */
271 bool
272 nfs4_put_deviceid_node(struct nfs4_deviceid_node *d)
273 {
274         if (test_bit(NFS_DEVICEID_NOCACHE, &d->flags)) {
275                 if (atomic_add_unless(&d->ref, -1, 2))
276                         return false;
277                 nfs4_delete_deviceid(d->ld, d->nfs_client, &d->deviceid);
278         }
279         if (!atomic_dec_and_test(&d->ref))
280                 return false;
281         d->ld->free_deviceid_node(d);
282         return true;
283 }
284 EXPORT_SYMBOL_GPL(nfs4_put_deviceid_node);
285 
286 void
287 nfs4_mark_deviceid_unavailable(struct nfs4_deviceid_node *node)
288 {
289         node->timestamp_unavailable = jiffies;
290         set_bit(NFS_DEVICEID_UNAVAILABLE, &node->flags);
291 }
292 EXPORT_SYMBOL_GPL(nfs4_mark_deviceid_unavailable);
293 
294 bool
295 nfs4_test_deviceid_unavailable(struct nfs4_deviceid_node *node)
296 {
297         if (test_bit(NFS_DEVICEID_UNAVAILABLE, &node->flags)) {
298                 unsigned long start, end;
299 
300                 end = jiffies;
301                 start = end - PNFS_DEVICE_RETRY_TIMEOUT;
302                 if (time_in_range(node->timestamp_unavailable, start, end))
303                         return true;
304                 clear_bit(NFS_DEVICEID_UNAVAILABLE, &node->flags);
305         }
306         return false;
307 }
308 EXPORT_SYMBOL_GPL(nfs4_test_deviceid_unavailable);
309 
310 static void
311 _deviceid_purge_client(const struct nfs_client *clp, long hash)
312 {
313         struct nfs4_deviceid_node *d;
314         HLIST_HEAD(tmp);
315 
316         spin_lock(&nfs4_deviceid_lock);
317         rcu_read_lock();
318         hlist_for_each_entry_rcu(d, &nfs4_deviceid_cache[hash], node)
319                 if (d->nfs_client == clp && atomic_read(&d->ref)) {
320                         hlist_del_init_rcu(&d->node);
321                         hlist_add_head(&d->tmpnode, &tmp);
322                         clear_bit(NFS_DEVICEID_NOCACHE, &d->flags);
323                 }
324         rcu_read_unlock();
325         spin_unlock(&nfs4_deviceid_lock);
326 
327         if (hlist_empty(&tmp))
328                 return;
329 
330         while (!hlist_empty(&tmp)) {
331                 d = hlist_entry(tmp.first, struct nfs4_deviceid_node, tmpnode);
332                 hlist_del(&d->tmpnode);
333                 nfs4_put_deviceid_node(d);
334         }
335 }
336 
337 void
338 nfs4_deviceid_purge_client(const struct nfs_client *clp)
339 {
340         long h;
341 
342         if (!(clp->cl_exchange_flags & EXCHGID4_FLAG_USE_PNFS_MDS))
343                 return;
344         for (h = 0; h < NFS4_DEVICE_ID_HASH_SIZE; h++)
345                 _deviceid_purge_client(clp, h);
346 }
347 
348 /*
349  * Stop use of all deviceids associated with an nfs_client
350  */
351 void
352 nfs4_deviceid_mark_client_invalid(struct nfs_client *clp)
353 {
354         struct nfs4_deviceid_node *d;
355         int i;
356 
357         rcu_read_lock();
358         for (i = 0; i < NFS4_DEVICE_ID_HASH_SIZE; i ++){
359                 hlist_for_each_entry_rcu(d, &nfs4_deviceid_cache[i], node)
360                         if (d->nfs_client == clp)
361                                 set_bit(NFS_DEVICEID_INVALID, &d->flags);
362         }
363         rcu_read_unlock();
364 }
365 

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