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author | Trond Myklebust <Trond.Myklebust@netapp.com> | 2007-07-02 13:58:33 -0400 |
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committer | Trond Myklebust <Trond.Myklebust@netapp.com> | 2007-07-10 23:40:39 -0400 |
commit | 9f958ab8858c75df800e0121b1920182820cbc39 (patch) | |
tree | 754bb9d68aac077825b40796e2acf716bce5df08 /fs/nfs/nfs4state.c | |
parent | 88d9093997e1c73ca98db41b5605dbde7783845f (diff) | |
download | kernel_samsung_smdk4412-9f958ab8858c75df800e0121b1920182820cbc39.zip kernel_samsung_smdk4412-9f958ab8858c75df800e0121b1920182820cbc39.tar.gz kernel_samsung_smdk4412-9f958ab8858c75df800e0121b1920182820cbc39.tar.bz2 |
NFSv4: Reduce the chances of an open_owner identifier collision
Currently we just use a 32-bit counter.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Diffstat (limited to 'fs/nfs/nfs4state.c')
-rw-r--r-- | fs/nfs/nfs4state.c | 193 |
1 files changed, 154 insertions, 39 deletions
diff --git a/fs/nfs/nfs4state.c b/fs/nfs/nfs4state.c index 0f79d56..ab0b5ab 100644 --- a/fs/nfs/nfs4state.c +++ b/fs/nfs/nfs4state.c @@ -44,6 +44,7 @@ #include <linux/nfs_idmap.h> #include <linux/kthread.h> #include <linux/module.h> +#include <linux/random.h> #include <linux/workqueue.h> #include <linux/bitops.h> @@ -69,18 +70,14 @@ static int nfs4_init_client(struct nfs_client *clp, struct rpc_cred *cred) return status; } -u32 -nfs4_alloc_lockowner_id(struct nfs_client *clp) -{ - return clp->cl_lockowner_id ++; -} - struct rpc_cred *nfs4_get_renew_cred(struct nfs_client *clp) { struct nfs4_state_owner *sp; + struct rb_node *pos; struct rpc_cred *cred = NULL; - list_for_each_entry(sp, &clp->cl_state_owners, so_list) { + for (pos = rb_first(&clp->cl_state_owners); pos != NULL; pos = rb_next(pos)) { + sp = rb_entry(pos, struct nfs4_state_owner, so_client_node); if (list_empty(&sp->so_states)) continue; cred = get_rpccred(sp->so_cred); @@ -92,32 +89,129 @@ struct rpc_cred *nfs4_get_renew_cred(struct nfs_client *clp) static struct rpc_cred *nfs4_get_setclientid_cred(struct nfs_client *clp) { struct nfs4_state_owner *sp; + struct rb_node *pos; - if (!list_empty(&clp->cl_state_owners)) { - sp = list_entry(clp->cl_state_owners.next, - struct nfs4_state_owner, so_list); + pos = rb_first(&clp->cl_state_owners); + if (pos != NULL) { + sp = rb_entry(pos, struct nfs4_state_owner, so_client_node); return get_rpccred(sp->so_cred); } return NULL; } +static void nfs_alloc_unique_id(struct rb_root *root, struct nfs_unique_id *new, + __u64 minval, int maxbits) +{ + struct rb_node **p, *parent; + struct nfs_unique_id *pos; + __u64 mask = ~0ULL; + + if (maxbits < 64) + mask = (1ULL << maxbits) - 1ULL; + + /* Ensure distribution is more or less flat */ + get_random_bytes(&new->id, sizeof(new->id)); + new->id &= mask; + if (new->id < minval) + new->id += minval; +retry: + p = &root->rb_node; + parent = NULL; + + while (*p != NULL) { + parent = *p; + pos = rb_entry(parent, struct nfs_unique_id, rb_node); + + if (new->id < pos->id) + p = &(*p)->rb_left; + else if (new->id > pos->id) + p = &(*p)->rb_right; + else + goto id_exists; + } + rb_link_node(&new->rb_node, parent, p); + rb_insert_color(&new->rb_node, root); + return; +id_exists: + for (;;) { + new->id++; + if (new->id < minval || (new->id & mask) != new->id) { + new->id = minval; + break; + } + parent = rb_next(parent); + if (parent == NULL) + break; + pos = rb_entry(parent, struct nfs_unique_id, rb_node); + if (new->id < pos->id) + break; + } + goto retry; +} + +static void nfs_free_unique_id(struct rb_root *root, struct nfs_unique_id *id) +{ + rb_erase(&id->rb_node, root); +} + static struct nfs4_state_owner * nfs4_find_state_owner(struct nfs_client *clp, struct rpc_cred *cred) { + struct rb_node **p = &clp->cl_state_owners.rb_node, + *parent = NULL; struct nfs4_state_owner *sp, *res = NULL; - list_for_each_entry(sp, &clp->cl_state_owners, so_list) { - if (sp->so_cred != cred) - continue; - atomic_inc(&sp->so_count); - /* Move to the head of the list */ - list_move(&sp->so_list, &clp->cl_state_owners); - res = sp; - break; + while (*p != NULL) { + parent = *p; + sp = rb_entry(parent, struct nfs4_state_owner, so_client_node); + + if (cred < sp->so_cred) + p = &parent->rb_left; + else if (cred > sp->so_cred) + p = &parent->rb_right; + else { + atomic_inc(&sp->so_count); + res = sp; + break; + } } return res; } +static struct nfs4_state_owner * +nfs4_insert_state_owner(struct nfs_client *clp, struct nfs4_state_owner *new) +{ + struct rb_node **p = &clp->cl_state_owners.rb_node, + *parent = NULL; + struct nfs4_state_owner *sp; + + while (*p != NULL) { + parent = *p; + sp = rb_entry(parent, struct nfs4_state_owner, so_client_node); + + if (new->so_cred < sp->so_cred) + p = &parent->rb_left; + else if (new->so_cred > sp->so_cred) + p = &parent->rb_right; + else { + atomic_inc(&sp->so_count); + return sp; + } + } + nfs_alloc_unique_id(&clp->cl_openowner_id, &new->so_owner_id, 1, 64); + rb_link_node(&new->so_client_node, parent, p); + rb_insert_color(&new->so_client_node, &clp->cl_state_owners); + return new; +} + +static void +nfs4_remove_state_owner(struct nfs_client *clp, struct nfs4_state_owner *sp) +{ + if (!RB_EMPTY_NODE(&sp->so_client_node)) + rb_erase(&sp->so_client_node, &clp->cl_state_owners); + nfs_free_unique_id(&clp->cl_openowner_id, &sp->so_owner_id); +} + /* * nfs4_alloc_state_owner(): this is called on the OPEN or CREATE path to * create a new state_owner. @@ -145,10 +239,14 @@ nfs4_alloc_state_owner(void) void nfs4_drop_state_owner(struct nfs4_state_owner *sp) { - struct nfs_client *clp = sp->so_client; - spin_lock(&clp->cl_lock); - list_del_init(&sp->so_list); - spin_unlock(&clp->cl_lock); + if (!RB_EMPTY_NODE(&sp->so_client_node)) { + struct nfs_client *clp = sp->so_client; + + spin_lock(&clp->cl_lock); + rb_erase(&sp->so_client_node, &clp->cl_state_owners); + RB_CLEAR_NODE(&sp->so_client_node); + spin_unlock(&clp->cl_lock); + } } /* @@ -160,22 +258,24 @@ struct nfs4_state_owner *nfs4_get_state_owner(struct nfs_server *server, struct struct nfs_client *clp = server->nfs_client; struct nfs4_state_owner *sp, *new; - new = nfs4_alloc_state_owner(); spin_lock(&clp->cl_lock); sp = nfs4_find_state_owner(clp, cred); - if (sp == NULL && new != NULL) { - list_add(&new->so_list, &clp->cl_state_owners); - new->so_client = clp; - new->so_id = nfs4_alloc_lockowner_id(clp); - new->so_cred = get_rpccred(cred); - sp = new; - new = NULL; - } spin_unlock(&clp->cl_lock); - kfree(new); if (sp != NULL) return sp; - return NULL; + new = nfs4_alloc_state_owner(); + if (new == NULL) + return NULL; + new->so_client = clp; + new->so_cred = cred; + spin_lock(&clp->cl_lock); + sp = nfs4_insert_state_owner(clp, new); + spin_unlock(&clp->cl_lock); + if (sp == new) + get_rpccred(cred); + else + kfree(new); + return sp; } /* @@ -189,7 +289,7 @@ void nfs4_put_state_owner(struct nfs4_state_owner *sp) if (!atomic_dec_and_lock(&sp->so_count, &clp->cl_lock)) return; - list_del(&sp->so_list); + nfs4_remove_state_owner(clp, sp); spin_unlock(&clp->cl_lock); put_rpccred(cred); kfree(sp); @@ -386,12 +486,22 @@ static struct nfs4_lock_state *nfs4_alloc_lock_state(struct nfs4_state *state, f atomic_set(&lsp->ls_count, 1); lsp->ls_owner = fl_owner; spin_lock(&clp->cl_lock); - lsp->ls_id = nfs4_alloc_lockowner_id(clp); + nfs_alloc_unique_id(&clp->cl_lockowner_id, &lsp->ls_id, 1, 64); spin_unlock(&clp->cl_lock); INIT_LIST_HEAD(&lsp->ls_locks); return lsp; } +static void nfs4_free_lock_state(struct nfs4_lock_state *lsp) +{ + struct nfs_client *clp = lsp->ls_state->owner->so_client; + + spin_lock(&clp->cl_lock); + nfs_free_unique_id(&clp->cl_lockowner_id, &lsp->ls_id); + spin_unlock(&clp->cl_lock); + kfree(lsp); +} + /* * Return a compatible lock_state. If no initialized lock_state structure * exists, return an uninitialized one. @@ -421,7 +531,8 @@ static struct nfs4_lock_state *nfs4_get_lock_state(struct nfs4_state *state, fl_ return NULL; } spin_unlock(&state->state_lock); - kfree(new); + if (new != NULL) + nfs4_free_lock_state(new); return lsp; } @@ -442,7 +553,7 @@ void nfs4_put_lock_state(struct nfs4_lock_state *lsp) if (list_empty(&state->lock_states)) clear_bit(LK_STATE_IN_USE, &state->flags); spin_unlock(&state->state_lock); - kfree(lsp); + nfs4_free_lock_state(lsp); } static void nfs4_fl_copy_lock(struct file_lock *dst, struct file_lock *src) @@ -719,11 +830,13 @@ out_err: static void nfs4_state_mark_reclaim(struct nfs_client *clp) { struct nfs4_state_owner *sp; + struct rb_node *pos; struct nfs4_state *state; struct nfs4_lock_state *lock; /* Reset all sequence ids to zero */ - list_for_each_entry(sp, &clp->cl_state_owners, so_list) { + for (pos = rb_first(&clp->cl_state_owners); pos != NULL; pos = rb_next(pos)) { + sp = rb_entry(pos, struct nfs4_state_owner, so_client_node); sp->so_seqid.counter = 0; sp->so_seqid.flags = 0; spin_lock(&sp->so_lock); @@ -742,6 +855,7 @@ static int reclaimer(void *ptr) { struct nfs_client *clp = ptr; struct nfs4_state_owner *sp; + struct rb_node *pos; struct nfs4_state_recovery_ops *ops; struct rpc_cred *cred; int status = 0; @@ -787,7 +901,8 @@ restart_loop: /* Mark all delegations for reclaim */ nfs_delegation_mark_reclaim(clp); /* Note: list is protected by exclusive lock on cl->cl_sem */ - list_for_each_entry(sp, &clp->cl_state_owners, so_list) { + for (pos = rb_first(&clp->cl_state_owners); pos != NULL; pos = rb_next(pos)) { + sp = rb_entry(pos, struct nfs4_state_owner, so_client_node); status = nfs4_reclaim_open_state(ops, sp); if (status < 0) { if (status == -NFS4ERR_NO_GRACE) { |