xref: /openbmc/linux/fs/nfs/pnfs_dev.c (revision 96562c45)
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 #include "nfs4trace.h"
38 
39 #define NFSDBG_FACILITY		NFSDBG_PNFS
40 
41 /*
42  * Device ID RCU cache. A device ID is unique per server and layout type.
43  */
44 #define NFS4_DEVICE_ID_HASH_BITS	5
45 #define NFS4_DEVICE_ID_HASH_SIZE	(1 << NFS4_DEVICE_ID_HASH_BITS)
46 #define NFS4_DEVICE_ID_HASH_MASK	(NFS4_DEVICE_ID_HASH_SIZE - 1)
47 
48 
49 static struct hlist_head nfs4_deviceid_cache[NFS4_DEVICE_ID_HASH_SIZE];
50 static DEFINE_SPINLOCK(nfs4_deviceid_lock);
51 
52 #ifdef NFS_DEBUG
53 void
nfs4_print_deviceid(const struct nfs4_deviceid * id)54 nfs4_print_deviceid(const struct nfs4_deviceid *id)
55 {
56 	u32 *p = (u32 *)id;
57 
58 	dprintk("%s: device id= [%x%x%x%x]\n", __func__,
59 		p[0], p[1], p[2], p[3]);
60 }
61 EXPORT_SYMBOL_GPL(nfs4_print_deviceid);
62 #endif
63 
64 static inline u32
nfs4_deviceid_hash(const struct nfs4_deviceid * id)65 nfs4_deviceid_hash(const struct nfs4_deviceid *id)
66 {
67 	unsigned char *cptr = (unsigned char *)id->data;
68 	unsigned int nbytes = NFS4_DEVICEID4_SIZE;
69 	u32 x = 0;
70 
71 	while (nbytes--) {
72 		x *= 37;
73 		x += *cptr++;
74 	}
75 	return x & NFS4_DEVICE_ID_HASH_MASK;
76 }
77 
78 static struct nfs4_deviceid_node *
_lookup_deviceid(const struct pnfs_layoutdriver_type * ld,const struct nfs_client * clp,const struct nfs4_deviceid * id,long hash)79 _lookup_deviceid(const struct pnfs_layoutdriver_type *ld,
80 		 const struct nfs_client *clp, const struct nfs4_deviceid *id,
81 		 long hash)
82 {
83 	struct nfs4_deviceid_node *d;
84 
85 	hlist_for_each_entry_rcu(d, &nfs4_deviceid_cache[hash], node)
86 		if (d->ld == ld && d->nfs_client == clp &&
87 		    !memcmp(&d->deviceid, id, sizeof(*id))) {
88 			if (atomic_read(&d->ref))
89 				return d;
90 			else
91 				continue;
92 		}
93 	return NULL;
94 }
95 
96 static struct nfs4_deviceid_node *
nfs4_get_device_info(struct nfs_server * server,const struct nfs4_deviceid * dev_id,const struct cred * cred,gfp_t gfp_flags)97 nfs4_get_device_info(struct nfs_server *server,
98 		const struct nfs4_deviceid *dev_id,
99 		const struct cred *cred, gfp_t gfp_flags)
100 {
101 	struct nfs4_deviceid_node *d = NULL;
102 	struct pnfs_device *pdev = NULL;
103 	struct page **pages = NULL;
104 	u32 max_resp_sz;
105 	int max_pages;
106 	int rc, i;
107 
108 	/*
109 	 * Use the session max response size as the basis for setting
110 	 * GETDEVICEINFO's maxcount
111 	 */
112 	max_resp_sz = server->nfs_client->cl_session->fc_attrs.max_resp_sz;
113 	if (server->pnfs_curr_ld->max_deviceinfo_size &&
114 	    server->pnfs_curr_ld->max_deviceinfo_size < max_resp_sz)
115 		max_resp_sz = server->pnfs_curr_ld->max_deviceinfo_size;
116 	max_pages = nfs_page_array_len(0, max_resp_sz);
117 	dprintk("%s: server %p max_resp_sz %u max_pages %d\n",
118 		__func__, server, max_resp_sz, max_pages);
119 
120 	pdev = kzalloc(sizeof(*pdev), gfp_flags);
121 	if (!pdev)
122 		return NULL;
123 
124 	pages = kcalloc(max_pages, sizeof(struct page *), gfp_flags);
125 	if (!pages)
126 		goto out_free_pdev;
127 
128 	for (i = 0; i < max_pages; i++) {
129 		pages[i] = alloc_page(gfp_flags);
130 		if (!pages[i])
131 			goto out_free_pages;
132 	}
133 
134 	memcpy(&pdev->dev_id, dev_id, sizeof(*dev_id));
135 	pdev->layout_type = server->pnfs_curr_ld->id;
136 	pdev->pages = pages;
137 	pdev->pgbase = 0;
138 	pdev->pglen = max_resp_sz;
139 	pdev->mincount = 0;
140 	pdev->maxcount = max_resp_sz - nfs41_maxgetdevinfo_overhead;
141 
142 	rc = nfs4_proc_getdeviceinfo(server, pdev, cred);
143 	dprintk("%s getdevice info returns %d\n", __func__, rc);
144 	if (rc)
145 		goto out_free_pages;
146 
147 	/*
148 	 * Found new device, need to decode it and then add it to the
149 	 * list of known devices for this mountpoint.
150 	 */
151 	d = server->pnfs_curr_ld->alloc_deviceid_node(server, pdev,
152 			gfp_flags);
153 	if (d && pdev->nocache)
154 		set_bit(NFS_DEVICEID_NOCACHE, &d->flags);
155 
156 out_free_pages:
157 	while (--i >= 0)
158 		__free_page(pages[i]);
159 	kfree(pages);
160 out_free_pdev:
161 	kfree(pdev);
162 	dprintk("<-- %s d %p\n", __func__, d);
163 	return d;
164 }
165 
166 /*
167  * Lookup a deviceid in cache and get a reference count on it if found
168  *
169  * @clp nfs_client associated with deviceid
170  * @id deviceid to look up
171  */
172 static struct nfs4_deviceid_node *
__nfs4_find_get_deviceid(struct nfs_server * server,const struct nfs4_deviceid * id,long hash)173 __nfs4_find_get_deviceid(struct nfs_server *server,
174 		const struct nfs4_deviceid *id, long hash)
175 {
176 	struct nfs4_deviceid_node *d;
177 
178 	rcu_read_lock();
179 	d = _lookup_deviceid(server->pnfs_curr_ld, server->nfs_client, id,
180 			hash);
181 	if (d != NULL && !atomic_inc_not_zero(&d->ref))
182 		d = NULL;
183 	rcu_read_unlock();
184 	return d;
185 }
186 
187 struct nfs4_deviceid_node *
nfs4_find_get_deviceid(struct nfs_server * server,const struct nfs4_deviceid * id,const struct cred * cred,gfp_t gfp_mask)188 nfs4_find_get_deviceid(struct nfs_server *server,
189 		const struct nfs4_deviceid *id, const struct cred *cred,
190 		gfp_t gfp_mask)
191 {
192 	long hash = nfs4_deviceid_hash(id);
193 	struct nfs4_deviceid_node *d, *new;
194 
195 	d = __nfs4_find_get_deviceid(server, id, hash);
196 	if (d)
197 		goto found;
198 
199 	new = nfs4_get_device_info(server, id, cred, gfp_mask);
200 	if (!new) {
201 		trace_nfs4_find_deviceid(server, id, -ENOENT);
202 		return new;
203 	}
204 
205 	spin_lock(&nfs4_deviceid_lock);
206 	d = __nfs4_find_get_deviceid(server, id, hash);
207 	if (d) {
208 		spin_unlock(&nfs4_deviceid_lock);
209 		server->pnfs_curr_ld->free_deviceid_node(new);
210 	} else {
211 		atomic_inc(&new->ref);
212 		hlist_add_head_rcu(&new->node, &nfs4_deviceid_cache[hash]);
213 		spin_unlock(&nfs4_deviceid_lock);
214 		d = new;
215 	}
216 found:
217 	trace_nfs4_find_deviceid(server, id, 0);
218 	return d;
219 }
220 EXPORT_SYMBOL_GPL(nfs4_find_get_deviceid);
221 
222 /*
223  * Remove a deviceid from cache
224  *
225  * @clp nfs_client associated with deviceid
226  * @id the deviceid to unhash
227  *
228  * @ret the unhashed node, if found and dereferenced to zero, NULL otherwise.
229  */
230 void
nfs4_delete_deviceid(const struct pnfs_layoutdriver_type * ld,const struct nfs_client * clp,const struct nfs4_deviceid * id)231 nfs4_delete_deviceid(const struct pnfs_layoutdriver_type *ld,
232 			 const struct nfs_client *clp, const struct nfs4_deviceid *id)
233 {
234 	struct nfs4_deviceid_node *d;
235 
236 	spin_lock(&nfs4_deviceid_lock);
237 	rcu_read_lock();
238 	d = _lookup_deviceid(ld, clp, id, nfs4_deviceid_hash(id));
239 	rcu_read_unlock();
240 	if (!d) {
241 		spin_unlock(&nfs4_deviceid_lock);
242 		return;
243 	}
244 	hlist_del_init_rcu(&d->node);
245 	clear_bit(NFS_DEVICEID_NOCACHE, &d->flags);
246 	spin_unlock(&nfs4_deviceid_lock);
247 
248 	/* balance the initial ref set in pnfs_insert_deviceid */
249 	nfs4_put_deviceid_node(d);
250 }
251 EXPORT_SYMBOL_GPL(nfs4_delete_deviceid);
252 
253 void
nfs4_init_deviceid_node(struct nfs4_deviceid_node * d,struct nfs_server * server,const struct nfs4_deviceid * id)254 nfs4_init_deviceid_node(struct nfs4_deviceid_node *d, struct nfs_server *server,
255 			const struct nfs4_deviceid *id)
256 {
257 	INIT_HLIST_NODE(&d->node);
258 	INIT_HLIST_NODE(&d->tmpnode);
259 	d->ld = server->pnfs_curr_ld;
260 	d->nfs_client = server->nfs_client;
261 	d->flags = 0;
262 	d->deviceid = *id;
263 	atomic_set(&d->ref, 1);
264 }
265 EXPORT_SYMBOL_GPL(nfs4_init_deviceid_node);
266 
267 /*
268  * Dereference a deviceid node and delete it when its reference count drops
269  * to zero.
270  *
271  * @d deviceid node to put
272  *
273  * return true iff the node was deleted
274  * Note that since the test for d->ref == 0 is sufficient to establish
275  * that the node is no longer hashed in the global device id cache.
276  */
277 bool
nfs4_put_deviceid_node(struct nfs4_deviceid_node * d)278 nfs4_put_deviceid_node(struct nfs4_deviceid_node *d)
279 {
280 	if (test_bit(NFS_DEVICEID_NOCACHE, &d->flags)) {
281 		if (atomic_add_unless(&d->ref, -1, 2))
282 			return false;
283 		nfs4_delete_deviceid(d->ld, d->nfs_client, &d->deviceid);
284 	}
285 	if (!atomic_dec_and_test(&d->ref))
286 		return false;
287 	trace_nfs4_deviceid_free(d->nfs_client, &d->deviceid);
288 	d->ld->free_deviceid_node(d);
289 	return true;
290 }
291 EXPORT_SYMBOL_GPL(nfs4_put_deviceid_node);
292 
293 void
nfs4_mark_deviceid_available(struct nfs4_deviceid_node * node)294 nfs4_mark_deviceid_available(struct nfs4_deviceid_node *node)
295 {
296 	if (test_bit(NFS_DEVICEID_UNAVAILABLE, &node->flags)) {
297 		clear_bit(NFS_DEVICEID_UNAVAILABLE, &node->flags);
298 		smp_mb__after_atomic();
299 	}
300 }
301 EXPORT_SYMBOL_GPL(nfs4_mark_deviceid_available);
302 
303 void
nfs4_mark_deviceid_unavailable(struct nfs4_deviceid_node * node)304 nfs4_mark_deviceid_unavailable(struct nfs4_deviceid_node *node)
305 {
306 	node->timestamp_unavailable = jiffies;
307 	smp_mb__before_atomic();
308 	set_bit(NFS_DEVICEID_UNAVAILABLE, &node->flags);
309 	smp_mb__after_atomic();
310 }
311 EXPORT_SYMBOL_GPL(nfs4_mark_deviceid_unavailable);
312 
313 bool
nfs4_test_deviceid_unavailable(struct nfs4_deviceid_node * node)314 nfs4_test_deviceid_unavailable(struct nfs4_deviceid_node *node)
315 {
316 	if (test_bit(NFS_DEVICEID_UNAVAILABLE, &node->flags)) {
317 		unsigned long start, end;
318 
319 		end = jiffies;
320 		start = end - PNFS_DEVICE_RETRY_TIMEOUT;
321 		if (time_in_range(node->timestamp_unavailable, start, end))
322 			return true;
323 		clear_bit(NFS_DEVICEID_UNAVAILABLE, &node->flags);
324 		smp_mb__after_atomic();
325 	}
326 	return false;
327 }
328 EXPORT_SYMBOL_GPL(nfs4_test_deviceid_unavailable);
329 
330 static void
_deviceid_purge_client(const struct nfs_client * clp,long hash)331 _deviceid_purge_client(const struct nfs_client *clp, long hash)
332 {
333 	struct nfs4_deviceid_node *d;
334 	HLIST_HEAD(tmp);
335 
336 	spin_lock(&nfs4_deviceid_lock);
337 	rcu_read_lock();
338 	hlist_for_each_entry_rcu(d, &nfs4_deviceid_cache[hash], node)
339 		if (d->nfs_client == clp && atomic_read(&d->ref)) {
340 			hlist_del_init_rcu(&d->node);
341 			hlist_add_head(&d->tmpnode, &tmp);
342 			clear_bit(NFS_DEVICEID_NOCACHE, &d->flags);
343 		}
344 	rcu_read_unlock();
345 	spin_unlock(&nfs4_deviceid_lock);
346 
347 	if (hlist_empty(&tmp))
348 		return;
349 
350 	while (!hlist_empty(&tmp)) {
351 		d = hlist_entry(tmp.first, struct nfs4_deviceid_node, tmpnode);
352 		hlist_del(&d->tmpnode);
353 		nfs4_put_deviceid_node(d);
354 	}
355 }
356 
357 void
nfs4_deviceid_purge_client(const struct nfs_client * clp)358 nfs4_deviceid_purge_client(const struct nfs_client *clp)
359 {
360 	long h;
361 
362 	if (!(clp->cl_exchange_flags & EXCHGID4_FLAG_USE_PNFS_MDS))
363 		return;
364 	for (h = 0; h < NFS4_DEVICE_ID_HASH_SIZE; h++)
365 		_deviceid_purge_client(clp, h);
366 }
367 
368 /*
369  * Stop use of all deviceids associated with an nfs_client
370  */
371 void
nfs4_deviceid_mark_client_invalid(struct nfs_client * clp)372 nfs4_deviceid_mark_client_invalid(struct nfs_client *clp)
373 {
374 	struct nfs4_deviceid_node *d;
375 	int i;
376 
377 	rcu_read_lock();
378 	for (i = 0; i < NFS4_DEVICE_ID_HASH_SIZE; i ++){
379 		hlist_for_each_entry_rcu(d, &nfs4_deviceid_cache[i], node)
380 			if (d->nfs_client == clp)
381 				set_bit(NFS_DEVICEID_INVALID, &d->flags);
382 	}
383 	rcu_read_unlock();
384 }
385