diff options
Diffstat (limited to 'fs/nfs/pnfs.c')
| -rw-r--r-- | fs/nfs/pnfs.c | 783 |
1 files changed, 783 insertions, 0 deletions
diff --git a/fs/nfs/pnfs.c b/fs/nfs/pnfs.c new file mode 100644 index 0000000..db77342 --- /dev/null +++ b/fs/nfs/pnfs.c @@ -0,0 +1,783 @@ +/* + * pNFS functions to call and manage layout drivers. + * + * Copyright (c) 2002 [year of first publication] + * The Regents of the University of Michigan + * All Rights Reserved + * + * Dean Hildebrand <dhildebz@umich.edu> + * + * 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 <linux/nfs_fs.h> +#include "internal.h" +#include "pnfs.h" + +#define NFSDBG_FACILITY NFSDBG_PNFS + +/* Locking: + * + * pnfs_spinlock: + * protects pnfs_modules_tbl. + */ +static DEFINE_SPINLOCK(pnfs_spinlock); + +/* + * pnfs_modules_tbl holds all pnfs modules + */ +static LIST_HEAD(pnfs_modules_tbl); + +/* Return the registered pnfs layout driver module matching given id */ +static struct pnfs_layoutdriver_type * +find_pnfs_driver_locked(u32 id) +{ + struct pnfs_layoutdriver_type *local; + + list_for_each_entry(local, &pnfs_modules_tbl, pnfs_tblid) + if (local->id == id) + goto out; + local = NULL; +out: + dprintk("%s: Searching for id %u, found %p\n", __func__, id, local); + return local; +} + +static struct pnfs_layoutdriver_type * +find_pnfs_driver(u32 id) +{ + struct pnfs_layoutdriver_type *local; + + spin_lock(&pnfs_spinlock); + local = find_pnfs_driver_locked(id); + spin_unlock(&pnfs_spinlock); + return local; +} + +void +unset_pnfs_layoutdriver(struct nfs_server *nfss) +{ + if (nfss->pnfs_curr_ld) { + nfss->pnfs_curr_ld->clear_layoutdriver(nfss); + module_put(nfss->pnfs_curr_ld->owner); + } + nfss->pnfs_curr_ld = NULL; +} + +/* + * Try to set the server's pnfs module to the pnfs layout type specified by id. + * Currently only one pNFS layout driver per filesystem is supported. + * + * @id layout type. Zero (illegal layout type) indicates pNFS not in use. + */ +void +set_pnfs_layoutdriver(struct nfs_server *server, u32 id) +{ + struct pnfs_layoutdriver_type *ld_type = NULL; + + if (id == 0) + goto out_no_driver; + if (!(server->nfs_client->cl_exchange_flags & + (EXCHGID4_FLAG_USE_NON_PNFS | EXCHGID4_FLAG_USE_PNFS_MDS))) { + printk(KERN_ERR "%s: id %u cl_exchange_flags 0x%x\n", __func__, + id, server->nfs_client->cl_exchange_flags); + goto out_no_driver; + } + ld_type = find_pnfs_driver(id); + if (!ld_type) { + request_module("%s-%u", LAYOUT_NFSV4_1_MODULE_PREFIX, id); + ld_type = find_pnfs_driver(id); + if (!ld_type) { + dprintk("%s: No pNFS module found for %u.\n", + __func__, id); + goto out_no_driver; + } + } + if (!try_module_get(ld_type->owner)) { + dprintk("%s: Could not grab reference on module\n", __func__); + goto out_no_driver; + } + server->pnfs_curr_ld = ld_type; + if (ld_type->set_layoutdriver(server)) { + printk(KERN_ERR + "%s: Error initializing mount point for layout driver %u.\n", + __func__, id); + module_put(ld_type->owner); + goto out_no_driver; + } + dprintk("%s: pNFS module for %u set\n", __func__, id); + return; + +out_no_driver: + dprintk("%s: Using NFSv4 I/O\n", __func__); + server->pnfs_curr_ld = NULL; +} + +int +pnfs_register_layoutdriver(struct pnfs_layoutdriver_type *ld_type) +{ + int status = -EINVAL; + struct pnfs_layoutdriver_type *tmp; + + if (ld_type->id == 0) { + printk(KERN_ERR "%s id 0 is reserved\n", __func__); + return status; + } + if (!ld_type->alloc_lseg || !ld_type->free_lseg) { + printk(KERN_ERR "%s Layout driver must provide " + "alloc_lseg and free_lseg.\n", __func__); + return status; + } + + spin_lock(&pnfs_spinlock); + tmp = find_pnfs_driver_locked(ld_type->id); + if (!tmp) { + list_add(&ld_type->pnfs_tblid, &pnfs_modules_tbl); + status = 0; + dprintk("%s Registering id:%u name:%s\n", __func__, ld_type->id, + ld_type->name); + } else { + printk(KERN_ERR "%s Module with id %d already loaded!\n", + __func__, ld_type->id); + } + spin_unlock(&pnfs_spinlock); + + return status; +} +EXPORT_SYMBOL_GPL(pnfs_register_layoutdriver); + +void +pnfs_unregister_layoutdriver(struct pnfs_layoutdriver_type *ld_type) +{ + dprintk("%s Deregistering id:%u\n", __func__, ld_type->id); + spin_lock(&pnfs_spinlock); + list_del(&ld_type->pnfs_tblid); + spin_unlock(&pnfs_spinlock); +} +EXPORT_SYMBOL_GPL(pnfs_unregister_layoutdriver); + +/* + * pNFS client layout cache + */ + +static void +get_layout_hdr_locked(struct pnfs_layout_hdr *lo) +{ + assert_spin_locked(&lo->inode->i_lock); + lo->refcount++; +} + +static void +put_layout_hdr_locked(struct pnfs_layout_hdr *lo) +{ + assert_spin_locked(&lo->inode->i_lock); + BUG_ON(lo->refcount == 0); + + lo->refcount--; + if (!lo->refcount) { + dprintk("%s: freeing layout cache %p\n", __func__, lo); + BUG_ON(!list_empty(&lo->layouts)); + NFS_I(lo->inode)->layout = NULL; + kfree(lo); + } +} + +void +put_layout_hdr(struct inode *inode) +{ + spin_lock(&inode->i_lock); + put_layout_hdr_locked(NFS_I(inode)->layout); + spin_unlock(&inode->i_lock); +} + +static void +init_lseg(struct pnfs_layout_hdr *lo, struct pnfs_layout_segment *lseg) +{ + INIT_LIST_HEAD(&lseg->fi_list); + kref_init(&lseg->kref); + lseg->layout = lo; +} + +/* Called without i_lock held, as the free_lseg call may sleep */ +static void +destroy_lseg(struct kref *kref) +{ + struct pnfs_layout_segment *lseg = + container_of(kref, struct pnfs_layout_segment, kref); + struct inode *ino = lseg->layout->inode; + + dprintk("--> %s\n", __func__); + NFS_SERVER(ino)->pnfs_curr_ld->free_lseg(lseg); + /* Matched by get_layout_hdr_locked in pnfs_insert_layout */ + put_layout_hdr(ino); +} + +static void +put_lseg(struct pnfs_layout_segment *lseg) +{ + if (!lseg) + return; + + dprintk("%s: lseg %p ref %d\n", __func__, lseg, + atomic_read(&lseg->kref.refcount)); + kref_put(&lseg->kref, destroy_lseg); +} + +static void +pnfs_clear_lseg_list(struct pnfs_layout_hdr *lo, struct list_head *tmp_list) +{ + struct pnfs_layout_segment *lseg, *next; + struct nfs_client *clp; + + dprintk("%s:Begin lo %p\n", __func__, lo); + + assert_spin_locked(&lo->inode->i_lock); + list_for_each_entry_safe(lseg, next, &lo->segs, fi_list) { + dprintk("%s: freeing lseg %p\n", __func__, lseg); + list_move(&lseg->fi_list, tmp_list); + } + clp = NFS_SERVER(lo->inode)->nfs_client; + spin_lock(&clp->cl_lock); + /* List does not take a reference, so no need for put here */ + list_del_init(&lo->layouts); + spin_unlock(&clp->cl_lock); + write_seqlock(&lo->seqlock); + clear_bit(NFS_LAYOUT_STATEID_SET, &lo->state); + write_sequnlock(&lo->seqlock); + + dprintk("%s:Return\n", __func__); +} + +static void +pnfs_free_lseg_list(struct list_head *tmp_list) +{ + struct pnfs_layout_segment *lseg; + + while (!list_empty(tmp_list)) { + lseg = list_entry(tmp_list->next, struct pnfs_layout_segment, + fi_list); + dprintk("%s calling put_lseg on %p\n", __func__, lseg); + list_del(&lseg->fi_list); + put_lseg(lseg); + } +} + +void +pnfs_destroy_layout(struct nfs_inode *nfsi) +{ + struct pnfs_layout_hdr *lo; + LIST_HEAD(tmp_list); + + spin_lock(&nfsi->vfs_inode.i_lock); + lo = nfsi->layout; + if (lo) { + pnfs_clear_lseg_list(lo, &tmp_list); + /* Matched by refcount set to 1 in alloc_init_layout_hdr */ + put_layout_hdr_locked(lo); + } + spin_unlock(&nfsi->vfs_inode.i_lock); + pnfs_free_lseg_list(&tmp_list); +} + +/* + * Called by the state manger to remove all layouts established under an + * expired lease. + */ +void +pnfs_destroy_all_layouts(struct nfs_client *clp) +{ + struct pnfs_layout_hdr *lo; + LIST_HEAD(tmp_list); + + spin_lock(&clp->cl_lock); + list_splice_init(&clp->cl_layouts, &tmp_list); + spin_unlock(&clp->cl_lock); + + while (!list_empty(&tmp_list)) { + lo = list_entry(tmp_list.next, struct pnfs_layout_hdr, + layouts); + dprintk("%s freeing layout for inode %lu\n", __func__, + lo->inode->i_ino); + pnfs_destroy_layout(NFS_I(lo->inode)); + } +} + +/* update lo->stateid with new if is more recent + * + * lo->stateid could be the open stateid, in which case we just use what given. + */ +static void +pnfs_set_layout_stateid(struct pnfs_layout_hdr *lo, + const nfs4_stateid *new) +{ + nfs4_stateid *old = &lo->stateid; + bool overwrite = false; + + write_seqlock(&lo->seqlock); + if (!test_bit(NFS_LAYOUT_STATEID_SET, &lo->state) || + memcmp(old->stateid.other, new->stateid.other, sizeof(new->stateid.other))) + overwrite = true; + else { + u32 oldseq, newseq; + + oldseq = be32_to_cpu(old->stateid.seqid); + newseq = be32_to_cpu(new->stateid.seqid); + if ((int)(newseq - oldseq) > 0) + overwrite = true; + } + if (overwrite) + memcpy(&old->stateid, &new->stateid, sizeof(new->stateid)); + write_sequnlock(&lo->seqlock); +} + +static void +pnfs_layout_from_open_stateid(struct pnfs_layout_hdr *lo, + struct nfs4_state *state) +{ + int seq; + + dprintk("--> %s\n", __func__); + write_seqlock(&lo->seqlock); + do { + seq = read_seqbegin(&state->seqlock); + memcpy(lo->stateid.data, state->stateid.data, + sizeof(state->stateid.data)); + } while (read_seqretry(&state->seqlock, seq)); + set_bit(NFS_LAYOUT_STATEID_SET, &lo->state); + write_sequnlock(&lo->seqlock); + dprintk("<-- %s\n", __func__); +} + +void +pnfs_get_layout_stateid(nfs4_stateid *dst, struct pnfs_layout_hdr *lo, + struct nfs4_state *open_state) +{ + int seq; + + dprintk("--> %s\n", __func__); + do { + seq = read_seqbegin(&lo->seqlock); + if (!test_bit(NFS_LAYOUT_STATEID_SET, &lo->state)) { + /* This will trigger retry of the read */ + pnfs_layout_from_open_stateid(lo, open_state); + } else + memcpy(dst->data, lo->stateid.data, + sizeof(lo->stateid.data)); + } while (read_seqretry(&lo->seqlock, seq)); + dprintk("<-- %s\n", __func__); +} + +/* +* Get layout from server. +* for now, assume that whole file layouts are requested. +* arg->offset: 0 +* arg->length: all ones +*/ +static struct pnfs_layout_segment * +send_layoutget(struct pnfs_layout_hdr *lo, + struct nfs_open_context *ctx, + u32 iomode) +{ + struct inode *ino = lo->inode; + struct nfs_server *server = NFS_SERVER(ino); + struct nfs4_layoutget *lgp; + struct pnfs_layout_segment *lseg = NULL; + + dprintk("--> %s\n", __func__); + + BUG_ON(ctx == NULL); + lgp = kzalloc(sizeof(*lgp), GFP_KERNEL); + if (lgp == NULL) { + put_layout_hdr(lo->inode); + return NULL; + } + lgp->args.minlength = NFS4_MAX_UINT64; + lgp->args.maxcount = PNFS_LAYOUT_MAXSIZE; + lgp->args.range.iomode = iomode; + lgp->args.range.offset = 0; + lgp->args.range.length = NFS4_MAX_UINT64; + lgp->args.type = server->pnfs_curr_ld->id; + lgp->args.inode = ino; + lgp->args.ctx = get_nfs_open_context(ctx); + lgp->lsegpp = &lseg; + + /* Synchronously retrieve layout information from server and + * store in lseg. + */ + nfs4_proc_layoutget(lgp); + if (!lseg) { + /* remember that LAYOUTGET failed and suspend trying */ + set_bit(lo_fail_bit(iomode), &lo->state); + } + return lseg; +} + +/* + * Compare two layout segments for sorting into layout cache. + * We want to preferentially return RW over RO layouts, so ensure those + * are seen first. + */ +static s64 +cmp_layout(u32 iomode1, u32 iomode2) +{ + /* read > read/write */ + return (int)(iomode2 == IOMODE_READ) - (int)(iomode1 == IOMODE_READ); +} + +static void +pnfs_insert_layout(struct pnfs_layout_hdr *lo, + struct pnfs_layout_segment *lseg) +{ + struct pnfs_layout_segment *lp; + int found = 0; + + dprintk("%s:Begin\n", __func__); + + assert_spin_locked(&lo->inode->i_lock); + if (list_empty(&lo->segs)) { + struct nfs_client *clp = NFS_SERVER(lo->inode)->nfs_client; + + spin_lock(&clp->cl_lock); + BUG_ON(!list_empty(&lo->layouts)); + list_add_tail(&lo->layouts, &clp->cl_layouts); + spin_unlock(&clp->cl_lock); + } + list_for_each_entry(lp, &lo->segs, fi_list) { + if (cmp_layout(lp->range.iomode, lseg->range.iomode) > 0) + continue; + list_add_tail(&lseg->fi_list, &lp->fi_list); + dprintk("%s: inserted lseg %p " + "iomode %d offset %llu length %llu before " + "lp %p iomode %d offset %llu length %llu\n", + __func__, lseg, lseg->range.iomode, + lseg->range.offset, lseg->range.length, + lp, lp->range.iomode, lp->range.offset, + lp->range.length); + found = 1; + break; + } + if (!found) { + list_add_tail(&lseg->fi_list, &lo->segs); + dprintk("%s: inserted lseg %p " + "iomode %d offset %llu length %llu at tail\n", + __func__, lseg, lseg->range.iomode, + lseg->range.offset, lseg->range.length); + } + get_layout_hdr_locked(lo); + + dprintk("%s:Return\n", __func__); +} + +static struct pnfs_layout_hdr * +alloc_init_layout_hdr(struct inode *ino) +{ + struct pnfs_layout_hdr *lo; + + lo = kzalloc(sizeof(struct pnfs_layout_hdr), GFP_KERNEL); + if (!lo) + return NULL; + lo->refcount = 1; + INIT_LIST_HEAD(&lo->layouts); + INIT_LIST_HEAD(&lo->segs); + seqlock_init(&lo->seqlock); + lo->inode = ino; + return lo; +} + +static struct pnfs_layout_hdr * +pnfs_find_alloc_layout(struct inode *ino) +{ + struct nfs_inode *nfsi = NFS_I(ino); + struct pnfs_layout_hdr *new = NULL; + + dprintk("%s Begin ino=%p layout=%p\n", __func__, ino, nfsi->layout); + + assert_spin_locked(&ino->i_lock); + if (nfsi->layout) + return nfsi->layout; + + spin_unlock(&ino->i_lock); + new = alloc_init_layout_hdr(ino); + spin_lock(&ino->i_lock); + + if (likely(nfsi->layout == NULL)) /* Won the race? */ + nfsi->layout = new; + else + kfree(new); + return nfsi->layout; +} + +/* + * iomode matching rules: + * iomode lseg match + * ----- ----- ----- + * ANY READ true + * ANY RW true + * RW READ false + * RW RW true + * READ READ true + * READ RW true + */ +static int +is_matching_lseg(struct pnfs_layout_segment *lseg, u32 iomode) +{ + return (iomode != IOMODE_RW || lseg->range.iomode == IOMODE_RW); +} + +/* + * lookup range in layout + */ +static struct pnfs_layout_segment * +pnfs_has_layout(struct pnfs_layout_hdr *lo, u32 iomode) +{ + struct pnfs_layout_segment *lseg, *ret = NULL; + + dprintk("%s:Begin\n", __func__); + + assert_spin_locked(&lo->inode->i_lock); + list_for_each_entry(lseg, &lo->segs, fi_list) { + if (is_matching_lseg(lseg, iomode)) { + ret = lseg; + break; + } + if (cmp_layout(iomode, lseg->range.iomode) > 0) + break; + } + + dprintk("%s:Return lseg %p ref %d\n", + __func__, ret, ret ? atomic_read(&ret->kref.refcount) : 0); + return ret; +} + +/* + * Layout segment is retreived from the server if not cached. + * The appropriate layout segment is referenced and returned to the caller. + */ +struct pnfs_layout_segment * +pnfs_update_layout(struct inode *ino, + struct nfs_open_context *ctx, + enum pnfs_iomode iomode) +{ + struct nfs_inode *nfsi = NFS_I(ino); + struct pnfs_layout_hdr *lo; + struct pnfs_layout_segment *lseg = NULL; + + if (!pnfs_enabled_sb(NFS_SERVER(ino))) + return NULL; + spin_lock(&ino->i_lock); + lo = pnfs_find_alloc_layout(ino); + if (lo == NULL) { + dprintk("%s ERROR: can't get pnfs_layout_hdr\n", __func__); + goto out_unlock; + } + + /* Check to see if the layout for the given range already exists */ + lseg = pnfs_has_layout(lo, iomode); + if (lseg) { + dprintk("%s: Using cached lseg %p for iomode %d)\n", + __func__, lseg, iomode); + goto out_unlock; + } + + /* if LAYOUTGET already failed once we don't try again */ + if (test_bit(lo_fail_bit(iomode), &nfsi->layout->state)) + goto out_unlock; + + get_layout_hdr_locked(lo); /* Matched in nfs4_layoutget_release */ + spin_unlock(&ino->i_lock); + + lseg = send_layoutget(lo, ctx, iomode); +out: + dprintk("%s end, state 0x%lx lseg %p\n", __func__, + nfsi->layout->state, lseg); + return lseg; +out_unlock: + spin_unlock(&ino->i_lock); + goto out; +} + +int +pnfs_layout_process(struct nfs4_layoutget *lgp) +{ + struct pnfs_layout_hdr *lo = NFS_I(lgp->args.inode)->layout; + struct nfs4_layoutget_res *res = &lgp->res; + struct pnfs_layout_segment *lseg; + struct inode *ino = lo->inode; + int status = 0; + + /* Inject layout blob into I/O device driver */ + lseg = NFS_SERVER(ino)->pnfs_curr_ld->alloc_lseg(lo, res); + if (!lseg || IS_ERR(lseg)) { + if (!lseg) + status = -ENOMEM; + else + status = PTR_ERR(lseg); + dprintk("%s: Could not allocate layout: error %d\n", + __func__, status); + goto out; + } + + spin_lock(&ino->i_lock); + init_lseg(lo, lseg); + lseg->range = res->range; + *lgp->lsegpp = lseg; + pnfs_insert_layout(lo, lseg); + + /* Done processing layoutget. Set the layout stateid */ + pnfs_set_layout_stateid(lo, &res->stateid); + spin_unlock(&ino->i_lock); +out: + return status; +} + +/* + * Device ID cache. Currently supports one layout type per struct nfs_client. + * Add layout type to the lookup key to expand to support multiple types. + */ +int +pnfs_alloc_init_deviceid_cache(struct nfs_client *clp, + void (*free_callback)(struct pnfs_deviceid_node *)) +{ + struct pnfs_deviceid_cache *c; + + c = kzalloc(sizeof(struct pnfs_deviceid_cache), GFP_KERNEL); + if (!c) + return -ENOMEM; + spin_lock(&clp->cl_lock); + if (clp->cl_devid_cache != NULL) { + atomic_inc(&clp->cl_devid_cache->dc_ref); + dprintk("%s [kref [%d]]\n", __func__, + atomic_read(&clp->cl_devid_cache->dc_ref)); + kfree(c); + } else { + /* kzalloc initializes hlists */ + spin_lock_init(&c->dc_lock); + atomic_set(&c->dc_ref, 1); + c->dc_free_callback = free_callback; + clp->cl_devid_cache = c; + dprintk("%s [new]\n", __func__); + } + spin_unlock(&clp->cl_lock); + return 0; +} +EXPORT_SYMBOL_GPL(pnfs_alloc_init_deviceid_cache); + +/* + * Called from pnfs_layoutdriver_type->free_lseg + * last layout segment reference frees deviceid + */ +void +pnfs_put_deviceid(struct pnfs_deviceid_cache *c, + struct pnfs_deviceid_node *devid) +{ + struct nfs4_deviceid *id = &devid->de_id; + struct pnfs_deviceid_node *d; + struct hlist_node *n; + long h = nfs4_deviceid_hash(id); + + dprintk("%s [%d]\n", __func__, atomic_read(&devid->de_ref)); + if (!atomic_dec_and_lock(&devid->de_ref, &c->dc_lock)) + return; + + hlist_for_each_entry_rcu(d, n, &c->dc_deviceids[h], de_node) + if (!memcmp(&d->de_id, id, sizeof(*id))) { + hlist_del_rcu(&d->de_node); + spin_unlock(&c->dc_lock); + synchronize_rcu(); + c->dc_free_callback(devid); + return; + } + spin_unlock(&c->dc_lock); + /* Why wasn't it found in the list? */ + BUG(); +} +EXPORT_SYMBOL_GPL(pnfs_put_deviceid); + +/* Find and reference a deviceid */ +struct pnfs_deviceid_node * +pnfs_find_get_deviceid(struct pnfs_deviceid_cache *c, struct nfs4_deviceid *id) +{ + struct pnfs_deviceid_node *d; + struct hlist_node *n; + long hash = nfs4_deviceid_hash(id); + + dprintk("--> %s hash %ld\n", __func__, hash); + rcu_read_lock(); + hlist_for_each_entry_rcu(d, n, &c->dc_deviceids[hash], de_node) { + if (!memcmp(&d->de_id, id, sizeof(*id))) { + if (!atomic_inc_not_zero(&d->de_ref)) { + goto fail; + } else { + rcu_read_unlock(); + return d; + } + } + } +fail: + rcu_read_unlock(); + return NULL; +} +EXPORT_SYMBOL_GPL(pnfs_find_get_deviceid); + +/* + * Add a deviceid to the cache. + * GETDEVICEINFOs for same deviceid can race. If deviceid is found, discard new + */ +struct pnfs_deviceid_node * +pnfs_add_deviceid(struct pnfs_deviceid_cache *c, struct pnfs_deviceid_node *new) +{ + struct pnfs_deviceid_node *d; + long hash = nfs4_deviceid_hash(&new->de_id); + + dprintk("--> %s hash %ld\n", __func__, hash); + spin_lock(&c->dc_lock); + d = pnfs_find_get_deviceid(c, &new->de_id); + if (d) { + spin_unlock(&c->dc_lock); + dprintk("%s [discard]\n", __func__); + c->dc_free_callback(new); + return d; + } + INIT_HLIST_NODE(&new->de_node); + atomic_set(&new->de_ref, 1); + hlist_add_head_rcu(&new->de_node, &c->dc_deviceids[hash]); + spin_unlock(&c->dc_lock); + dprintk("%s [new]\n", __func__); + return new; +} +EXPORT_SYMBOL_GPL(pnfs_add_deviceid); + +void +pnfs_put_deviceid_cache(struct nfs_client *clp) +{ + struct pnfs_deviceid_cache *local = clp->cl_devid_cache; + + dprintk("--> %s cl_devid_cache %p\n", __func__, clp->cl_devid_cache); + if (atomic_dec_and_lock(&local->dc_ref, &clp->cl_lock)) { + int i; + /* Verify cache is empty */ + for (i = 0; i < NFS4_DEVICE_ID_HASH_SIZE; i++) + BUG_ON(!hlist_empty(&local->dc_deviceids[i])); + clp->cl_devid_cache = NULL; + spin_unlock(&clp->cl_lock); + kfree(local); + } +} +EXPORT_SYMBOL_GPL(pnfs_put_deviceid_cache); |
