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278 lines
7.3 KiB
C
278 lines
7.3 KiB
C
/*
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* Device operations for the pnfs client.
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*
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* Copyright (c) 2002
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* The Regents of the University of Michigan
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* All Rights Reserved
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*
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* Dean Hildebrand <dhildebz@umich.edu>
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* Garth Goodson <Garth.Goodson@netapp.com>
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*
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* Permission is granted to use, copy, create derivative works, and
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* redistribute this software and such derivative works for any purpose,
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* so long as the name of the University of Michigan is not used in
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* any advertising or publicity pertaining to the use or distribution
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* of this software without specific, written prior authorization. If
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* the above copyright notice or any other identification of the
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* University of Michigan is included in any copy of any portion of
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* this software, then the disclaimer below must also be included.
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*
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* This software is provided as is, without representation or warranty
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* of any kind either express or implied, including without limitation
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* the implied warranties of merchantability, fitness for a particular
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* purpose, or noninfringement. The Regents of the University of
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* Michigan shall not be liable for any damages, including special,
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* indirect, incidental, or consequential damages, with respect to any
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* claim arising out of or in connection with the use of the software,
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* even if it has been or is hereafter advised of the possibility of
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* such damages.
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*/
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#include <linux/export.h>
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#include "pnfs.h"
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#define NFSDBG_FACILITY NFSDBG_PNFS
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/*
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* Device ID RCU cache. A device ID is unique per server and layout type.
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*/
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#define NFS4_DEVICE_ID_HASH_BITS 5
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#define NFS4_DEVICE_ID_HASH_SIZE (1 << NFS4_DEVICE_ID_HASH_BITS)
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#define NFS4_DEVICE_ID_HASH_MASK (NFS4_DEVICE_ID_HASH_SIZE - 1)
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static struct hlist_head nfs4_deviceid_cache[NFS4_DEVICE_ID_HASH_SIZE];
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static DEFINE_SPINLOCK(nfs4_deviceid_lock);
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#ifdef NFS_DEBUG
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void
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nfs4_print_deviceid(const struct nfs4_deviceid *id)
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{
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u32 *p = (u32 *)id;
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dprintk("%s: device id= [%x%x%x%x]\n", __func__,
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p[0], p[1], p[2], p[3]);
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}
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EXPORT_SYMBOL_GPL(nfs4_print_deviceid);
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#endif
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static inline u32
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nfs4_deviceid_hash(const struct nfs4_deviceid *id)
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{
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unsigned char *cptr = (unsigned char *)id->data;
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unsigned int nbytes = NFS4_DEVICEID4_SIZE;
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u32 x = 0;
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while (nbytes--) {
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x *= 37;
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x += *cptr++;
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}
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return x & NFS4_DEVICE_ID_HASH_MASK;
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}
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static struct nfs4_deviceid_node *
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_lookup_deviceid(const struct pnfs_layoutdriver_type *ld,
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const struct nfs_client *clp, const struct nfs4_deviceid *id,
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long hash)
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{
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struct nfs4_deviceid_node *d;
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struct hlist_node *n;
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hlist_for_each_entry_rcu(d, n, &nfs4_deviceid_cache[hash], node)
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if (d->ld == ld && d->nfs_client == clp &&
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!memcmp(&d->deviceid, id, sizeof(*id))) {
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if (atomic_read(&d->ref))
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return d;
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else
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continue;
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}
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return NULL;
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}
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/*
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* Lookup a deviceid in cache and get a reference count on it if found
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*
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* @clp nfs_client associated with deviceid
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* @id deviceid to look up
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*/
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static struct nfs4_deviceid_node *
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_find_get_deviceid(const struct pnfs_layoutdriver_type *ld,
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const struct nfs_client *clp, const struct nfs4_deviceid *id,
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long hash)
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{
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struct nfs4_deviceid_node *d;
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rcu_read_lock();
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d = _lookup_deviceid(ld, clp, id, hash);
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if (d != NULL)
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atomic_inc(&d->ref);
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rcu_read_unlock();
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return d;
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}
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struct nfs4_deviceid_node *
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nfs4_find_get_deviceid(const struct pnfs_layoutdriver_type *ld,
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const struct nfs_client *clp, const struct nfs4_deviceid *id)
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{
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return _find_get_deviceid(ld, clp, id, nfs4_deviceid_hash(id));
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}
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EXPORT_SYMBOL_GPL(nfs4_find_get_deviceid);
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/*
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* Remove a deviceid from cache
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*
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* @clp nfs_client associated with deviceid
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* @id the deviceid to unhash
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*
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* @ret the unhashed node, if found and dereferenced to zero, NULL otherwise.
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*/
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void
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nfs4_delete_deviceid(const struct pnfs_layoutdriver_type *ld,
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const struct nfs_client *clp, const struct nfs4_deviceid *id)
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{
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struct nfs4_deviceid_node *d;
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spin_lock(&nfs4_deviceid_lock);
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rcu_read_lock();
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d = _lookup_deviceid(ld, clp, id, nfs4_deviceid_hash(id));
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rcu_read_unlock();
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if (!d) {
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spin_unlock(&nfs4_deviceid_lock);
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return;
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}
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hlist_del_init_rcu(&d->node);
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spin_unlock(&nfs4_deviceid_lock);
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synchronize_rcu();
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/* balance the initial ref set in pnfs_insert_deviceid */
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if (atomic_dec_and_test(&d->ref))
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d->ld->free_deviceid_node(d);
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}
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EXPORT_SYMBOL_GPL(nfs4_delete_deviceid);
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void
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nfs4_init_deviceid_node(struct nfs4_deviceid_node *d,
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const struct pnfs_layoutdriver_type *ld,
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const struct nfs_client *nfs_client,
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const struct nfs4_deviceid *id)
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{
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INIT_HLIST_NODE(&d->node);
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INIT_HLIST_NODE(&d->tmpnode);
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d->ld = ld;
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d->nfs_client = nfs_client;
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d->flags = 0;
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d->deviceid = *id;
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atomic_set(&d->ref, 1);
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}
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EXPORT_SYMBOL_GPL(nfs4_init_deviceid_node);
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/*
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* Uniquely initialize and insert a deviceid node into cache
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*
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* @new new deviceid node
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* Note that the caller must set up the following members:
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* new->ld
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* new->nfs_client
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* new->deviceid
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*
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* @ret the inserted node, if none found, otherwise, the found entry.
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*/
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struct nfs4_deviceid_node *
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nfs4_insert_deviceid_node(struct nfs4_deviceid_node *new)
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{
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struct nfs4_deviceid_node *d;
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long hash;
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spin_lock(&nfs4_deviceid_lock);
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hash = nfs4_deviceid_hash(&new->deviceid);
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d = _find_get_deviceid(new->ld, new->nfs_client, &new->deviceid, hash);
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if (d) {
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spin_unlock(&nfs4_deviceid_lock);
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return d;
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}
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hlist_add_head_rcu(&new->node, &nfs4_deviceid_cache[hash]);
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spin_unlock(&nfs4_deviceid_lock);
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atomic_inc(&new->ref);
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return new;
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}
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EXPORT_SYMBOL_GPL(nfs4_insert_deviceid_node);
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/*
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* Dereference a deviceid node and delete it when its reference count drops
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* to zero.
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*
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* @d deviceid node to put
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*
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* return true iff the node was deleted
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* Note that since the test for d->ref == 0 is sufficient to establish
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* that the node is no longer hashed in the global device id cache.
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*/
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bool
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nfs4_put_deviceid_node(struct nfs4_deviceid_node *d)
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{
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if (!atomic_dec_and_test(&d->ref))
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return false;
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d->ld->free_deviceid_node(d);
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return true;
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}
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EXPORT_SYMBOL_GPL(nfs4_put_deviceid_node);
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static void
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_deviceid_purge_client(const struct nfs_client *clp, long hash)
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{
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struct nfs4_deviceid_node *d;
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struct hlist_node *n;
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HLIST_HEAD(tmp);
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spin_lock(&nfs4_deviceid_lock);
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rcu_read_lock();
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hlist_for_each_entry_rcu(d, n, &nfs4_deviceid_cache[hash], node)
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if (d->nfs_client == clp && atomic_read(&d->ref)) {
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hlist_del_init_rcu(&d->node);
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hlist_add_head(&d->tmpnode, &tmp);
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}
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rcu_read_unlock();
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spin_unlock(&nfs4_deviceid_lock);
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if (hlist_empty(&tmp))
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return;
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synchronize_rcu();
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while (!hlist_empty(&tmp)) {
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d = hlist_entry(tmp.first, struct nfs4_deviceid_node, tmpnode);
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hlist_del(&d->tmpnode);
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if (atomic_dec_and_test(&d->ref))
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d->ld->free_deviceid_node(d);
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}
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}
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void
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nfs4_deviceid_purge_client(const struct nfs_client *clp)
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{
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long h;
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if (!(clp->cl_exchange_flags & EXCHGID4_FLAG_USE_PNFS_MDS))
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return;
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for (h = 0; h < NFS4_DEVICE_ID_HASH_SIZE; h++)
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_deviceid_purge_client(clp, h);
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}
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/*
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* Stop use of all deviceids associated with an nfs_client
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*/
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void
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nfs4_deviceid_mark_client_invalid(struct nfs_client *clp)
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{
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struct nfs4_deviceid_node *d;
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struct hlist_node *n;
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int i;
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rcu_read_lock();
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for (i = 0; i < NFS4_DEVICE_ID_HASH_SIZE; i ++){
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hlist_for_each_entry_rcu(d, n, &nfs4_deviceid_cache[i], node)
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if (d->nfs_client == clp)
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set_bit(NFS_DEVICEID_INVALID, &d->flags);
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}
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rcu_read_unlock();
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}
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