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author | Benny Halevy <bhalevy@panasas.com> | 2011-05-20 04:14:47 +0200 |
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committer | Boaz Harrosh <bharrosh@panasas.com> | 2011-05-29 11:09:48 +0200 |
commit | a1eaecbc4c8307e27772d6584ef85a2e93250661 (patch) | |
tree | 940549d45db98a5bcfe22501de0bbe9c96de4c8e /fs/nfs/pnfs_dev.c | |
parent | pnfs: resolve header dependency in pnfs.h (diff) | |
download | linux-a1eaecbc4c8307e27772d6584ef85a2e93250661.tar.xz linux-a1eaecbc4c8307e27772d6584ef85a2e93250661.zip |
NFSv4.1: make deviceid cache global
Move deviceid cache from the pnfs files layout driver to the
generic layer in preparation for the objects layout driver.
Signed-off-by: Benny Halevy <bhalevy@panasas.com>
Diffstat (limited to 'fs/nfs/pnfs_dev.c')
-rw-r--r-- | fs/nfs/pnfs_dev.c | 156 |
1 files changed, 156 insertions, 0 deletions
diff --git a/fs/nfs/pnfs_dev.c b/fs/nfs/pnfs_dev.c new file mode 100644 index 000000000000..bf05189a7cbf --- /dev/null +++ b/fs/nfs/pnfs_dev.c @@ -0,0 +1,156 @@ +/* + * 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; +} + +/* + * 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 * +nfs4_find_get_deviceid(const struct nfs_client *clp, const struct nfs4_deviceid *id) +{ + struct nfs4_deviceid_node *d; + struct hlist_node *n; + long hash = nfs4_deviceid_hash(id); + + rcu_read_lock(); + 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_inc_not_zero(&d->ref)) + goto fail; + rcu_read_unlock(); + return d; + } + } +fail: + rcu_read_unlock(); + return NULL; +} +EXPORT_SYMBOL_GPL(nfs4_find_get_deviceid); + +void +nfs4_init_deviceid_node(struct nfs4_deviceid_node *d, + const struct nfs_client *nfs_client, + const struct nfs4_deviceid *id) +{ + d->nfs_client = nfs_client; + d->deviceid = *id; +} +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 new->nfs_client and 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); + d = nfs4_find_get_deviceid(new->nfs_client, &new->deviceid); + if (d) { + spin_unlock(&nfs4_deviceid_lock); + return d; + } + + INIT_HLIST_NODE(&new->node); + atomic_set(&new->ref, 1); + hash = nfs4_deviceid_hash(&new->deviceid); + 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(); + return true; +} +EXPORT_SYMBOL_GPL(nfs4_put_deviceid_node); |