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#define PNFS_DEVICE_RETRY_TIMEOUT (120*HZ)
  47
  48static struct hlist_head nfs4_deviceid_cache[NFS4_DEVICE_ID_HASH_SIZE];
  49static DEFINE_SPINLOCK(nfs4_deviceid_lock);
  50
  51#ifdef NFS_DEBUG
  52void
  53nfs4_print_deviceid(const struct nfs4_deviceid *id)
  54{
  55        u32 *p = (u32 *)id;
  56
  57        dprintk("%s: device id= [%x%x%x%x]\n", __func__,
  58                p[0], p[1], p[2], p[3]);
  59}
  60EXPORT_SYMBOL_GPL(nfs4_print_deviceid);
  61#endif
  62
  63static inline u32
  64nfs4_deviceid_hash(const struct nfs4_deviceid *id)
  65{
  66        unsigned char *cptr = (unsigned char *)id->data;
  67        unsigned int nbytes = NFS4_DEVICEID4_SIZE;
  68        u32 x = 0;
  69
  70        while (nbytes--) {
  71                x *= 37;
  72                x += *cptr++;
  73        }
  74        return x & NFS4_DEVICE_ID_HASH_MASK;
  75}
  76
  77static struct nfs4_deviceid_node *
  78_lookup_deviceid(const struct pnfs_layoutdriver_type *ld,
  79                 const struct nfs_client *clp, const struct nfs4_deviceid *id,
  80                 long hash)
  81{
  82        struct nfs4_deviceid_node *d;
  83
  84        hlist_for_each_entry_rcu(d, &nfs4_deviceid_cache[hash], node)
  85                if (d->ld == ld && d->nfs_client == clp &&
  86                    !memcmp(&d->deviceid, id, sizeof(*id))) {
  87                        if (atomic_read(&d->ref))
  88                                return d;
  89                        else
  90                                continue;
  91                }
  92        return NULL;
  93}
  94
  95static struct nfs4_deviceid_node *
  96nfs4_get_device_info(struct nfs_server *server,
  97                const struct nfs4_deviceid *dev_id,
  98                struct rpc_cred *cred, gfp_t gfp_flags)
  99{
 100        struct nfs4_deviceid_node *d = NULL;
 101        struct pnfs_device *pdev = NULL;
 102        struct page **pages = NULL;
 103        u32 max_resp_sz;
 104        int max_pages;
 105        int rc, i;
 106
 107        /*
 108         * Use the session max response size as the basis for setting
 109         * GETDEVICEINFO's maxcount
 110         */
 111        max_resp_sz = server->nfs_client->cl_session->fc_attrs.max_resp_sz;
 112        if (server->pnfs_curr_ld->max_deviceinfo_size &&
 113            server->pnfs_curr_ld->max_deviceinfo_size < max_resp_sz)
 114                max_resp_sz = server->pnfs_curr_ld->max_deviceinfo_size;
 115        max_pages = nfs_page_array_len(0, max_resp_sz);
 116        dprintk("%s: server %p max_resp_sz %u max_pages %d\n",
 117                __func__, server, max_resp_sz, max_pages);
 118
 119        pdev = kzalloc(sizeof(*pdev), gfp_flags);
 120        if (!pdev)
 121                return NULL;
 122
 123        pages = kcalloc(max_pages, sizeof(struct page *), gfp_flags);
 124        if (!pages)
 125                goto out_free_pdev;
 126
 127        for (i = 0; i < max_pages; i++) {
 128                pages[i] = alloc_page(gfp_flags);
 129                if (!pages[i])
 130                        goto out_free_pages;
 131        }
 132
 133        memcpy(&pdev->dev_id, dev_id, sizeof(*dev_id));
 134        pdev->layout_type = server->pnfs_curr_ld->id;
 135        pdev->pages = pages;
 136        pdev->pgbase = 0;
 137        pdev->pglen = max_resp_sz;
 138        pdev->mincount = 0;
 139        pdev->maxcount = max_resp_sz - nfs41_maxgetdevinfo_overhead;
 140
 141        rc = nfs4_proc_getdeviceinfo(server, pdev, cred);
 142        dprintk("%s getdevice info returns %d\n", __func__, rc);
 143        if (rc)
 144                goto out_free_pages;
 145
 146        /*
 147         * Found new device, need to decode it and then add it to the
 148         * list of known devices for this mountpoint.
 149         */
 150        d = server->pnfs_curr_ld->alloc_deviceid_node(server, pdev,
 151                        gfp_flags);
 152
 153out_free_pages:
 154        for (i = 0; i < max_pages; i++)
 155                __free_page(pages[i]);
 156        kfree(pages);
 157out_free_pdev:
 158        kfree(pdev);
 159        dprintk("<-- %s d %p\n", __func__, d);
 160        return d;
 161}
 162
 163/*
 164 * Lookup a deviceid in cache and get a reference count on it if found
 165 *
 166 * @clp nfs_client associated with deviceid
 167 * @id deviceid to look up
 168 */
 169static struct nfs4_deviceid_node *
 170__nfs4_find_get_deviceid(struct nfs_server *server,
 171                const struct nfs4_deviceid *id, long hash)
 172{
 173        struct nfs4_deviceid_node *d;
 174
 175        rcu_read_lock();
 176        d = _lookup_deviceid(server->pnfs_curr_ld, server->nfs_client, id,
 177                        hash);
 178        if (d != NULL)
 179                atomic_inc(&d->ref);
 180        rcu_read_unlock();
 181        return d;
 182}
 183
 184struct nfs4_deviceid_node *
 185nfs4_find_get_deviceid(struct nfs_server *server,
 186                const struct nfs4_deviceid *id, struct rpc_cred *cred,
 187                gfp_t gfp_mask)
 188{
 189        long hash = nfs4_deviceid_hash(id);
 190        struct nfs4_deviceid_node *d, *new;
 191
 192        d = __nfs4_find_get_deviceid(server, id, hash);
 193        if (d)
 194                return d;
 195
 196        new = nfs4_get_device_info(server, id, cred, gfp_mask);
 197        if (!new)
 198                return new;
 199
 200        spin_lock(&nfs4_deviceid_lock);
 201        d = __nfs4_find_get_deviceid(server, id, hash);
 202        if (d) {
 203                spin_unlock(&nfs4_deviceid_lock);
 204                server->pnfs_curr_ld->free_deviceid_node(new);
 205                return d;
 206        }
 207        hlist_add_head_rcu(&new->node, &nfs4_deviceid_cache[hash]);
 208        atomic_inc(&new->ref);
 209        spin_unlock(&nfs4_deviceid_lock);
 210
 211        return new;
 212}
 213EXPORT_SYMBOL_GPL(nfs4_find_get_deviceid);
 214
 215/*
 216 * Remove a deviceid from cache
 217 *
 218 * @clp nfs_client associated with deviceid
 219 * @id the deviceid to unhash
 220 *
 221 * @ret the unhashed node, if found and dereferenced to zero, NULL otherwise.
 222 */
 223void
 224nfs4_delete_deviceid(const struct pnfs_layoutdriver_type *ld,
 225                         const struct nfs_client *clp, const struct nfs4_deviceid *id)
 226{
 227        struct nfs4_deviceid_node *d;
 228
 229        spin_lock(&nfs4_deviceid_lock);
 230        rcu_read_lock();
 231        d = _lookup_deviceid(ld, clp, id, nfs4_deviceid_hash(id));
 232        rcu_read_unlock();
 233        if (!d) {
 234                spin_unlock(&nfs4_deviceid_lock);
 235                return;
 236        }
 237        hlist_del_init_rcu(&d->node);
 238        spin_unlock(&nfs4_deviceid_lock);
 239        synchronize_rcu();
 240
 241        /* balance the initial ref set in pnfs_insert_deviceid */
 242        if (atomic_dec_and_test(&d->ref))
 243                d->ld->free_deviceid_node(d);
 244}
 245EXPORT_SYMBOL_GPL(nfs4_delete_deviceid);
 246
 247void
 248nfs4_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}
 259EXPORT_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 */
 271bool
 272nfs4_put_deviceid_node(struct nfs4_deviceid_node *d)
 273{
 274        if (!atomic_dec_and_test(&d->ref))
 275                return false;
 276        d->ld->free_deviceid_node(d);
 277        return true;
 278}
 279EXPORT_SYMBOL_GPL(nfs4_put_deviceid_node);
 280
 281void
 282nfs4_mark_deviceid_unavailable(struct nfs4_deviceid_node *node)
 283{
 284        node->timestamp_unavailable = jiffies;
 285        set_bit(NFS_DEVICEID_UNAVAILABLE, &node->flags);
 286}
 287EXPORT_SYMBOL_GPL(nfs4_mark_deviceid_unavailable);
 288
 289bool
 290nfs4_test_deviceid_unavailable(struct nfs4_deviceid_node *node)
 291{
 292        if (test_bit(NFS_DEVICEID_UNAVAILABLE, &node->flags)) {
 293                unsigned long start, end;
 294
 295                end = jiffies;
 296                start = end - PNFS_DEVICE_RETRY_TIMEOUT;
 297                if (time_in_range(node->timestamp_unavailable, start, end))
 298                        return true;
 299                clear_bit(NFS_DEVICEID_UNAVAILABLE, &node->flags);
 300        }
 301        return false;
 302}
 303EXPORT_SYMBOL_GPL(nfs4_test_deviceid_unavailable);
 304
 305static void
 306_deviceid_purge_client(const struct nfs_client *clp, long hash)
 307{
 308        struct nfs4_deviceid_node *d;
 309        HLIST_HEAD(tmp);
 310
 311        spin_lock(&nfs4_deviceid_lock);
 312        rcu_read_lock();
 313        hlist_for_each_entry_rcu(d, &nfs4_deviceid_cache[hash], node)
 314                if (d->nfs_client == clp && atomic_read(&d->ref)) {
 315                        hlist_del_init_rcu(&d->node);
 316                        hlist_add_head(&d->tmpnode, &tmp);
 317                }
 318        rcu_read_unlock();
 319        spin_unlock(&nfs4_deviceid_lock);
 320
 321        if (hlist_empty(&tmp))
 322                return;
 323
 324        synchronize_rcu();
 325        while (!hlist_empty(&tmp)) {
 326                d = hlist_entry(tmp.first, struct nfs4_deviceid_node, tmpnode);
 327                hlist_del(&d->tmpnode);
 328                if (atomic_dec_and_test(&d->ref))
 329                        d->ld->free_deviceid_node(d);
 330        }
 331}
 332
 333void
 334nfs4_deviceid_purge_client(const struct nfs_client *clp)
 335{
 336        long h;
 337
 338        if (!(clp->cl_exchange_flags & EXCHGID4_FLAG_USE_PNFS_MDS))
 339                return;
 340        for (h = 0; h < NFS4_DEVICE_ID_HASH_SIZE; h++)
 341                _deviceid_purge_client(clp, h);
 342}
 343
 344/*
 345 * Stop use of all deviceids associated with an nfs_client
 346 */
 347void
 348nfs4_deviceid_mark_client_invalid(struct nfs_client *clp)
 349{
 350        struct nfs4_deviceid_node *d;
 351        int i;
 352
 353        rcu_read_lock();
 354        for (i = 0; i < NFS4_DEVICE_ID_HASH_SIZE; i ++){
 355                hlist_for_each_entry_rcu(d, &nfs4_deviceid_cache[i], node)
 356                        if (d->nfs_client == clp)
 357                                set_bit(NFS_DEVICEID_INVALID, &d->flags);
 358        }
 359        rcu_read_unlock();
 360}
 361