From 87dda67e7386ba7d2164391ea58b34e028d8157b Mon Sep 17 00:00:00 2001 From: Trond Myklebust Date: Tue, 20 Nov 2012 19:49:20 -0500 Subject: NFSv4.1: Allow SEQUENCE to resize the slot table on the fly Instead of an array of slots, use a singly linked list of slots that can be dynamically appended to or shrunk. Signed-off-by: Trond Myklebust --- fs/nfs/nfs4proc.c | 174 +++++++++++++++++++++++++++++++++++------------------- 1 file changed, 114 insertions(+), 60 deletions(-) (limited to 'fs/nfs/nfs4proc.c') diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c index 1792ece8b53c..fc65300172e1 100644 --- a/fs/nfs/nfs4proc.c +++ b/fs/nfs/nfs4proc.c @@ -396,6 +396,27 @@ static void renew_lease(const struct nfs_server *server, unsigned long timestamp #if defined(CONFIG_NFS_V4_1) +/* + * nfs4_shrink_slot_table - free retired slots from the slot table + */ +static void nfs4_shrink_slot_table(struct nfs4_slot_table *tbl, u32 newsize) +{ + struct nfs4_slot **p; + if (newsize >= tbl->max_slots) + return; + + p = &tbl->slots; + while (newsize--) + p = &(*p)->next; + while (*p) { + struct nfs4_slot *slot = *p; + + *p = slot->next; + kfree(slot); + tbl->max_slots--; + } +} + /* * nfs4_free_slot - free a slot and efficiently update slot table. * @@ -499,7 +520,7 @@ static void nfs41_set_target_slotid_locked(struct nfs4_slot_table *tbl, tbl->target_highest_slotid = target_highest_slotid; tbl->generation++; - max_slotid = min(tbl->max_slots - 1, tbl->target_highest_slotid); + max_slotid = min(NFS4_MAX_SLOT_TABLE - 1, tbl->target_highest_slotid); for (i = tbl->max_slotid + 1; i <= max_slotid; i++) rpc_wake_up_next(&tbl->slot_tbl_waitq); tbl->max_slotid = max_slotid; @@ -516,16 +537,12 @@ void nfs41_set_target_slotid(struct nfs4_slot_table *tbl, static void nfs41_set_server_slotid_locked(struct nfs4_slot_table *tbl, u32 highest_slotid) { - unsigned int max_slotid, i; - if (tbl->server_highest_slotid == highest_slotid) return; if (tbl->highest_used_slotid > highest_slotid) return; - max_slotid = min(tbl->max_slots - 1, highest_slotid); - /* Reset the seq_nr for deallocated slots */ - for (i = tbl->server_highest_slotid + 1; i <= max_slotid; i++) - tbl->slots[i].seq_nr = 1; + /* Deallocate slots */ + nfs4_shrink_slot_table(tbl, highest_slotid + 1); tbl->server_highest_slotid = highest_slotid; } @@ -612,6 +629,42 @@ static int nfs4_sequence_done(struct rpc_task *task, return nfs41_sequence_done(task, res); } +static struct nfs4_slot *nfs4_new_slot(struct nfs4_slot_table *tbl, + u32 slotid, u32 seq_init, gfp_t gfp_mask) +{ + struct nfs4_slot *slot; + + slot = kzalloc(sizeof(*slot), gfp_mask); + if (slot) { + slot->table = tbl; + slot->slot_nr = slotid; + slot->seq_nr = seq_init; + } + return slot; +} + +static struct nfs4_slot *nfs4_find_or_create_slot(struct nfs4_slot_table *tbl, + u32 slotid, u32 seq_init, gfp_t gfp_mask) +{ + struct nfs4_slot **p, *slot; + + p = &tbl->slots; + for (;;) { + if (*p == NULL) { + *p = nfs4_new_slot(tbl, tbl->max_slots, + seq_init, gfp_mask); + if (*p == NULL) + break; + tbl->max_slots++; + } + slot = *p; + if (slot->slot_nr == slotid) + return slot; + p = &slot->next; + } + return NULL; +} + /* * nfs4_alloc_slot - efficiently look for a free slot * @@ -628,15 +681,17 @@ static struct nfs4_slot *nfs4_alloc_slot(struct nfs4_slot_table *tbl) dprintk("--> %s used_slots=%04lx highest_used=%u max_slots=%u\n", __func__, tbl->used_slots[0], tbl->highest_used_slotid, - tbl->max_slots); + tbl->max_slotid + 1); slotid = find_first_zero_bit(tbl->used_slots, tbl->max_slotid + 1); if (slotid > tbl->max_slotid) goto out; + ret = nfs4_find_or_create_slot(tbl, slotid, 1, GFP_NOWAIT); + if (ret == NULL) + goto out; __set_bit(slotid, tbl->used_slots); if (slotid > tbl->highest_used_slotid || tbl->highest_used_slotid == NFS4_NO_SLOT) tbl->highest_used_slotid = slotid; - ret = &tbl->slots[slotid]; ret->renewal_time = jiffies; ret->generation = tbl->generation; @@ -5718,67 +5773,56 @@ int nfs4_proc_get_lease_time(struct nfs_client *clp, struct nfs_fsinfo *fsinfo) return status; } -struct nfs4_slot *nfs4_alloc_slots(struct nfs4_slot_table *table, - u32 max_slots, gfp_t gfp_flags) +static int nfs4_grow_slot_table(struct nfs4_slot_table *tbl, + u32 max_reqs, u32 ivalue) { - struct nfs4_slot *tbl; - u32 i; - - tbl = kmalloc_array(max_slots, sizeof(*tbl), gfp_flags); - if (tbl != NULL) { - for (i = 0; i < max_slots; i++) { - tbl[i].table = table; - tbl[i].slot_nr = i; - } - } - return tbl; + if (max_reqs <= tbl->max_slots) + return 0; + if (nfs4_find_or_create_slot(tbl, max_reqs - 1, ivalue, GFP_NOFS)) + return 0; + return -ENOMEM; } -static void nfs4_add_and_init_slots(struct nfs4_slot_table *tbl, - struct nfs4_slot *new, - u32 max_slots, +static void nfs4_reset_slot_table(struct nfs4_slot_table *tbl, + u32 server_highest_slotid, u32 ivalue) { - struct nfs4_slot *old = NULL; - u32 i; + struct nfs4_slot **p; - spin_lock(&tbl->slot_tbl_lock); - if (new) { - old = tbl->slots; - tbl->slots = new; - tbl->max_slots = max_slots; + nfs4_shrink_slot_table(tbl, server_highest_slotid + 1); + p = &tbl->slots; + while (*p) { + (*p)->seq_nr = ivalue; + p = &(*p)->next; } tbl->highest_used_slotid = NFS4_NO_SLOT; - tbl->target_highest_slotid = max_slots - 1; - tbl->server_highest_slotid = max_slots - 1; - tbl->max_slotid = max_slots - 1; - for (i = 0; i < tbl->max_slots; i++) - tbl->slots[i].seq_nr = ivalue; - spin_unlock(&tbl->slot_tbl_lock); - kfree(old); + tbl->target_highest_slotid = server_highest_slotid; + tbl->server_highest_slotid = server_highest_slotid; + tbl->max_slotid = server_highest_slotid; } /* * (re)Initialise a slot table */ -static int nfs4_realloc_slot_table(struct nfs4_slot_table *tbl, u32 max_reqs, - u32 ivalue) +static int nfs4_realloc_slot_table(struct nfs4_slot_table *tbl, + u32 max_reqs, u32 ivalue) { - struct nfs4_slot *new = NULL; - int ret = -ENOMEM; + int ret; dprintk("--> %s: max_reqs=%u, tbl->max_slots %d\n", __func__, max_reqs, tbl->max_slots); - /* Does the newly negotiated max_reqs match the existing slot table? */ - if (max_reqs != tbl->max_slots) { - new = nfs4_alloc_slots(tbl, max_reqs, GFP_NOFS); - if (!new) - goto out; - } - ret = 0; + if (max_reqs > NFS4_MAX_SLOT_TABLE) + max_reqs = NFS4_MAX_SLOT_TABLE; + + ret = nfs4_grow_slot_table(tbl, max_reqs, ivalue); + if (ret) + goto out; + + spin_lock(&tbl->slot_tbl_lock); + nfs4_reset_slot_table(tbl, max_reqs - 1, ivalue); + spin_unlock(&tbl->slot_tbl_lock); - nfs4_add_and_init_slots(tbl, new, max_reqs, ivalue); dprintk("%s: tbl=%p slots=%p max_slots=%d\n", __func__, tbl, tbl->slots, tbl->max_slots); out: @@ -5786,18 +5830,28 @@ out: return ret; } +int nfs4_resize_slot_table(struct nfs4_slot_table *tbl, + u32 max_reqs, u32 ivalue) +{ + int ret; + + if (max_reqs > NFS4_MAX_SLOT_TABLE) + max_reqs = NFS4_MAX_SLOT_TABLE; + ret = nfs4_grow_slot_table(tbl, max_reqs, ivalue); + if (ret) + return ret; + spin_lock(&tbl->slot_tbl_lock); + nfs4_shrink_slot_table(tbl, max_reqs); + tbl->max_slotid = max_reqs - 1; + spin_unlock(&tbl->slot_tbl_lock); + return 0; +} + /* Destroy the slot table */ static void nfs4_destroy_slot_tables(struct nfs4_session *session) { - if (session->fc_slot_table.slots != NULL) { - kfree(session->fc_slot_table.slots); - session->fc_slot_table.slots = NULL; - } - if (session->bc_slot_table.slots != NULL) { - kfree(session->bc_slot_table.slots); - session->bc_slot_table.slots = NULL; - } - return; + nfs4_shrink_slot_table(&session->fc_slot_table, 0); + nfs4_shrink_slot_table(&session->bc_slot_table, 0); } /* -- cgit v1.2.3