| /* |
| * Device operations for the pnfs client. |
| * |
| * Copyright (c) 2002 |
| * The Regents of the University of Michigan |
| * All Rights Reserved |
| * |
| * Dean Hildebrand <dhildebz@umich.edu> |
| * Garth Goodson <Garth.Goodson@netapp.com> |
| * |
| * Permission is granted to use, copy, create derivative works, and |
| * redistribute this software and such derivative works for any purpose, |
| * so long as the name of the University of Michigan is not used in |
| * any advertising or publicity pertaining to the use or distribution |
| * of this software without specific, written prior authorization. If |
| * the above copyright notice or any other identification of the |
| * University of Michigan is included in any copy of any portion of |
| * this software, then the disclaimer below must also be included. |
| * |
| * This software is provided as is, without representation or warranty |
| * of any kind either express or implied, including without limitation |
| * the implied warranties of merchantability, fitness for a particular |
| * purpose, or noninfringement. The Regents of the University of |
| * Michigan shall not be liable for any damages, including special, |
| * indirect, incidental, or consequential damages, with respect to any |
| * claim arising out of or in connection with the use of the software, |
| * even if it has been or is hereafter advised of the possibility of |
| * such damages. |
| */ |
| |
| #include "pnfs.h" |
| |
| #define NFSDBG_FACILITY NFSDBG_PNFS |
| |
| /* |
| * Device ID RCU cache. A device ID is unique per server and layout type. |
| */ |
| #define NFS4_DEVICE_ID_HASH_BITS 5 |
| #define NFS4_DEVICE_ID_HASH_SIZE (1 << NFS4_DEVICE_ID_HASH_BITS) |
| #define NFS4_DEVICE_ID_HASH_MASK (NFS4_DEVICE_ID_HASH_SIZE - 1) |
| |
| static struct hlist_head nfs4_deviceid_cache[NFS4_DEVICE_ID_HASH_SIZE]; |
| static DEFINE_SPINLOCK(nfs4_deviceid_lock); |
| |
| void |
| nfs4_print_deviceid(const struct nfs4_deviceid *id) |
| { |
| u32 *p = (u32 *)id; |
| |
| dprintk("%s: device id= [%x%x%x%x]\n", __func__, |
| p[0], p[1], p[2], p[3]); |
| } |
| EXPORT_SYMBOL_GPL(nfs4_print_deviceid); |
| |
| static inline u32 |
| nfs4_deviceid_hash(const struct nfs4_deviceid *id) |
| { |
| unsigned char *cptr = (unsigned char *)id->data; |
| unsigned int nbytes = NFS4_DEVICEID4_SIZE; |
| u32 x = 0; |
| |
| while (nbytes--) { |
| x *= 37; |
| x += *cptr++; |
| } |
| return x & NFS4_DEVICE_ID_HASH_MASK; |
| } |
| |
| static struct nfs4_deviceid_node * |
| _lookup_deviceid(const struct nfs_client *clp, const struct nfs4_deviceid *id, |
| long hash) |
| { |
| struct nfs4_deviceid_node *d; |
| struct hlist_node *n; |
| |
| hlist_for_each_entry_rcu(d, n, &nfs4_deviceid_cache[hash], node) |
| if (d->nfs_client == clp && !memcmp(&d->deviceid, id, sizeof(*id))) { |
| if (atomic_read(&d->ref)) |
| return d; |
| else |
| continue; |
| } |
| return NULL; |
| } |
| |
| /* |
| * Lookup a deviceid in cache and get a reference count on it if found |
| * |
| * @clp nfs_client associated with deviceid |
| * @id deviceid to look up |
| */ |
| struct nfs4_deviceid_node * |
| _find_get_deviceid(const struct nfs_client *clp, const struct nfs4_deviceid *id, |
| long hash) |
| { |
| struct nfs4_deviceid_node *d; |
| |
| rcu_read_lock(); |
| d = _lookup_deviceid(clp, id, hash); |
| if (d && !atomic_inc_not_zero(&d->ref)) |
| d = NULL; |
| rcu_read_unlock(); |
| return d; |
| } |
| |
| struct nfs4_deviceid_node * |
| nfs4_find_get_deviceid(const struct nfs_client *clp, const struct nfs4_deviceid *id) |
| { |
| return _find_get_deviceid(clp, id, nfs4_deviceid_hash(id)); |
| } |
| EXPORT_SYMBOL_GPL(nfs4_find_get_deviceid); |
| |
| /* |
| * Unhash and put deviceid |
| * |
| * @clp nfs_client associated with deviceid |
| * @id the deviceid to unhash |
| * |
| * @ret the unhashed node, if found and dereferenced to zero, NULL otherwise. |
| */ |
| struct nfs4_deviceid_node * |
| nfs4_unhash_put_deviceid(const struct nfs_client *clp, const struct nfs4_deviceid *id) |
| { |
| struct nfs4_deviceid_node *d; |
| |
| spin_lock(&nfs4_deviceid_lock); |
| rcu_read_lock(); |
| d = _lookup_deviceid(clp, id, nfs4_deviceid_hash(id)); |
| rcu_read_unlock(); |
| if (!d) { |
| spin_unlock(&nfs4_deviceid_lock); |
| return NULL; |
| } |
| hlist_del_init_rcu(&d->node); |
| spin_unlock(&nfs4_deviceid_lock); |
| synchronize_rcu(); |
| |
| /* balance the initial ref set in pnfs_insert_deviceid */ |
| if (atomic_dec_and_test(&d->ref)) |
| return d; |
| |
| return NULL; |
| } |
| EXPORT_SYMBOL_GPL(nfs4_unhash_put_deviceid); |
| |
| /* |
| * Delete a deviceid from cache |
| * |
| * @clp struct nfs_client qualifying the deviceid |
| * @id deviceid to delete |
| */ |
| void |
| nfs4_delete_deviceid(const struct nfs_client *clp, const struct nfs4_deviceid *id) |
| { |
| struct nfs4_deviceid_node *d; |
| |
| d = nfs4_unhash_put_deviceid(clp, id); |
| if (!d) |
| return; |
| d->ld->free_deviceid_node(d); |
| } |
| EXPORT_SYMBOL_GPL(nfs4_delete_deviceid); |
| |
| void |
| nfs4_init_deviceid_node(struct nfs4_deviceid_node *d, |
| const struct pnfs_layoutdriver_type *ld, |
| const struct nfs_client *nfs_client, |
| const struct nfs4_deviceid *id) |
| { |
| INIT_HLIST_NODE(&d->node); |
| d->ld = ld; |
| d->nfs_client = nfs_client; |
| d->deviceid = *id; |
| atomic_set(&d->ref, 1); |
| } |
| EXPORT_SYMBOL_GPL(nfs4_init_deviceid_node); |
| |
| /* |
| * Uniquely initialize and insert a deviceid node into cache |
| * |
| * @new new deviceid node |
| * Note that the caller must set up the following members: |
| * new->ld |
| * new->nfs_client |
| * new->deviceid |
| * |
| * @ret the inserted node, if none found, otherwise, the found entry. |
| */ |
| struct nfs4_deviceid_node * |
| nfs4_insert_deviceid_node(struct nfs4_deviceid_node *new) |
| { |
| struct nfs4_deviceid_node *d; |
| long hash; |
| |
| spin_lock(&nfs4_deviceid_lock); |
| hash = nfs4_deviceid_hash(&new->deviceid); |
| d = _find_get_deviceid(new->nfs_client, &new->deviceid, hash); |
| if (d) { |
| spin_unlock(&nfs4_deviceid_lock); |
| return d; |
| } |
| |
| hlist_add_head_rcu(&new->node, &nfs4_deviceid_cache[hash]); |
| spin_unlock(&nfs4_deviceid_lock); |
| |
| return new; |
| } |
| EXPORT_SYMBOL_GPL(nfs4_insert_deviceid_node); |
| |
| /* |
| * Dereference a deviceid node and delete it when its reference count drops |
| * to zero. |
| * |
| * @d deviceid node to put |
| * |
| * @ret true iff the node was deleted |
| */ |
| bool |
| nfs4_put_deviceid_node(struct nfs4_deviceid_node *d) |
| { |
| if (!atomic_dec_and_lock(&d->ref, &nfs4_deviceid_lock)) |
| return false; |
| hlist_del_init_rcu(&d->node); |
| spin_unlock(&nfs4_deviceid_lock); |
| synchronize_rcu(); |
| d->ld->free_deviceid_node(d); |
| return true; |
| } |
| EXPORT_SYMBOL_GPL(nfs4_put_deviceid_node); |
| |
| static void |
| _deviceid_purge_client(const struct nfs_client *clp, long hash) |
| { |
| struct nfs4_deviceid_node *d; |
| struct hlist_node *n, *next; |
| HLIST_HEAD(tmp); |
| |
| rcu_read_lock(); |
| hlist_for_each_entry_rcu(d, n, &nfs4_deviceid_cache[hash], node) |
| if (d->nfs_client == clp && atomic_read(&d->ref)) { |
| hlist_del_init_rcu(&d->node); |
| hlist_add_head(&d->node, &tmp); |
| } |
| rcu_read_unlock(); |
| |
| if (hlist_empty(&tmp)) |
| return; |
| |
| synchronize_rcu(); |
| hlist_for_each_entry_safe(d, n, next, &tmp, node) |
| if (atomic_dec_and_test(&d->ref)) |
| d->ld->free_deviceid_node(d); |
| } |
| |
| void |
| nfs4_deviceid_purge_client(const struct nfs_client *clp) |
| { |
| long h; |
| |
| spin_lock(&nfs4_deviceid_lock); |
| for (h = 0; h < NFS4_DEVICE_ID_HASH_SIZE; h++) |
| _deviceid_purge_client(clp, h); |
| spin_unlock(&nfs4_deviceid_lock); |
| } |