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nfsd4: use idr for stateid's
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The idr system is designed exactly for generating id and looking up
integer id's.  Thanks to Trond for pointing it out.

Signed-off-by: J. Bruce Fields <bfields@redhat.com>
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J. Bruce Fields committed Sep 26, 2011
1 parent 2a74aba commit 6136d2b
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Showing 2 changed files with 73 additions and 52 deletions.
124 changes: 73 additions & 51 deletions fs/nfsd/nfs4state.c
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Original file line number Diff line number Diff line change
Expand Up @@ -32,6 +32,7 @@
*
*/

#include <linux/idr.h>
#include <linux/file.h>
#include <linux/fs.h>
#include <linux/slab.h>
Expand All @@ -49,7 +50,6 @@
time_t nfsd4_lease = 90; /* default lease time */
time_t nfsd4_grace = 90;
static time_t boot_time;
static u32 current_stateid = 1;
static stateid_t zerostateid; /* bits all 0 */
static stateid_t onestateid; /* bits all 1 */
static u64 current_sessionid = 1;
Expand Down Expand Up @@ -149,24 +149,15 @@ static struct list_head open_ownerstr_hashtbl[OPEN_OWNER_HASH_SIZE];
#define FILE_HASH_BITS 8
#define FILE_HASH_SIZE (1 << FILE_HASH_BITS)

/* hash table for (open)nfs4_ol_stateid */
#define STATEID_HASH_BITS 10
#define STATEID_HASH_SIZE (1 << STATEID_HASH_BITS)
#define STATEID_HASH_MASK (STATEID_HASH_SIZE - 1)
struct idr stateids;

static unsigned int file_hashval(struct inode *ino)
{
/* XXX: why are we hashing on inode pointer, anyway? */
return hash_ptr(ino, FILE_HASH_BITS);
}

static unsigned int stateid_hashval(stateid_t *s)
{
return opaque_hashval(&s->si_opaque, sizeof(stateid_opaque_t)) & STATEID_HASH_MASK;
}

static struct list_head file_hashtbl[FILE_HASH_SIZE];
static struct list_head stateid_hashtbl[STATEID_HASH_SIZE];

static void __nfs4_file_get_access(struct nfs4_file *fp, int oflag)
{
Expand Down Expand Up @@ -215,33 +206,60 @@ static void nfs4_file_put_access(struct nfs4_file *fp, int oflag)
__nfs4_file_put_access(fp, oflag);
}

static inline void hash_stid(struct nfs4_stid *stid)
static inline int get_new_stid(struct nfs4_stid *stid)
{
stateid_t *s = &stid->sc_stateid;
unsigned int hashval;
static int min_stateid = 0;
int new_stid;
int error;

if (!idr_pre_get(&stateids, GFP_KERNEL))
return -ENOMEM;

error = idr_get_new_above(&stateids, stid, min_stateid, &new_stid);
/*
* All this code is currently serialized; the preallocation
* above should still be ours:
*/
BUG_ON(error);
/*
* It shouldn't be a problem to reuse an opaque stateid value.
* I don't think it is for 4.1. But with 4.0 I worry that, for
* example, a stray write retransmission could be accepted by
* the server when it should have been rejected. Therefore,
* adopt a trick from the sctp code to attempt to maximize the
* amount of time until an id is reused, by ensuring they always
* "increase" (mod INT_MAX):
*/

hashval = stateid_hashval(s);
list_add(&stid->sc_hash, &stateid_hashtbl[hashval]);
min_stateid = new_stid+1;
if (min_stateid == INT_MAX)
min_stateid = 0;
return new_stid;
}

static void init_stid(struct nfs4_stid *stid, struct nfs4_client *cl, unsigned char type)
static inline __be32 init_stid(struct nfs4_stid *stid, struct nfs4_client *cl, unsigned char type)
{
stateid_t *s = &stid->sc_stateid;
int new_id;

stid->sc_type = type;
stid->sc_client = cl;
s->si_opaque.so_clid = cl->cl_clientid;
s->si_opaque.so_id = current_stateid++;
new_id = get_new_stid(stid);
if (new_id < 0)
return nfserr_jukebox;
s->si_opaque.so_id = (u32)new_id;
/* Will be incremented before return to client: */
s->si_generation = 0;
hash_stid(stid);
return 0;
}

static struct nfs4_delegation *
alloc_init_deleg(struct nfs4_client *clp, struct nfs4_ol_stateid *stp, struct svc_fh *current_fh, u32 type)
{
struct nfs4_delegation *dp;
struct nfs4_file *fp = stp->st_file;
__be32 status;

dprintk("NFSD alloc_init_deleg\n");
/*
Expand All @@ -258,11 +276,15 @@ alloc_init_deleg(struct nfs4_client *clp, struct nfs4_ol_stateid *stp, struct sv
dp = kmem_cache_alloc(deleg_slab, GFP_KERNEL);
if (dp == NULL)
return dp;
init_stid(&dp->dl_stid, clp, NFS4_DELEG_STID);
status = init_stid(&dp->dl_stid, clp, NFS4_DELEG_STID);
if (status) {
kmem_cache_free(deleg_slab, dp);
return NULL;
}
/*
* delegation seqid's are never incremented. The 4.1 special
* meaning of seqid 0 isn't really meaningful, really, but let's
* avoid 0 anyway just for consistency and use 1:
* meaning of seqid 0 isn't meaningful, really, but let's avoid
* 0 anyway just for consistency and use 1:
*/
dp->dl_stid.sc_stateid.si_generation = 1;
num_delegations++;
Expand Down Expand Up @@ -300,11 +322,16 @@ static void nfs4_put_deleg_lease(struct nfs4_file *fp)
}
}

static void unhash_stid(struct nfs4_stid *s)
{
idr_remove(&stateids, s->sc_stateid.si_opaque.so_id);
}

/* Called under the state lock. */
static void
unhash_delegation(struct nfs4_delegation *dp)
{
list_del_init(&dp->dl_stid.sc_hash);
unhash_stid(&dp->dl_stid);
list_del_init(&dp->dl_perclnt);
spin_lock(&recall_lock);
list_del_init(&dp->dl_perfile);
Expand Down Expand Up @@ -457,7 +484,7 @@ static void release_lock_stateid(struct nfs4_ol_stateid *stp)
struct file *file;

unhash_generic_stateid(stp);
list_del(&stp->st_stid.sc_hash);
unhash_stid(&stp->st_stid);
file = find_any_file(stp->st_file);
if (file)
locks_remove_posix(file, (fl_owner_t)lockowner(stp->st_stateowner));
Expand Down Expand Up @@ -506,7 +533,7 @@ static void unhash_open_stateid(struct nfs4_ol_stateid *stp)
static void release_open_stateid(struct nfs4_ol_stateid *stp)
{
unhash_open_stateid(stp);
list_del(&stp->st_stid.sc_hash);
unhash_stid(&stp->st_stid);
free_generic_stateid(stp);
}

Expand All @@ -528,7 +555,7 @@ static void release_last_closed_stateid(struct nfs4_openowner *oo)
struct nfs4_ol_stateid *s = oo->oo_last_closed_stid;

if (s) {
list_del_init(&s->st_stid.sc_hash);
unhash_stid(&s->st_stid);
free_generic_stateid(s);
oo->oo_last_closed_stid = NULL;
}
Expand Down Expand Up @@ -1099,23 +1126,9 @@ static void gen_confirm(struct nfs4_client *clp)
*p++ = i++;
}

static int
same_stateid(stateid_t *id_one, stateid_t *id_two)
{
return 0 == memcmp(&id_one->si_opaque, &id_two->si_opaque,
sizeof(stateid_opaque_t));
}

static struct nfs4_stid *find_stateid(stateid_t *t)
{
struct nfs4_stid *s;
unsigned int hashval;

hashval = stateid_hashval(t);
list_for_each_entry(s, &stateid_hashtbl[hashval], sc_hash)
if (same_stateid(&s->sc_stateid, t))
return s;
return NULL;
return idr_find(&stateids, t->si_opaque.so_id);
}

static struct nfs4_stid *find_stateid_by_type(stateid_t *t, char typemask)
Expand Down Expand Up @@ -2342,12 +2355,14 @@ alloc_init_open_stateowner(unsigned int strhashval, struct nfs4_client *clp, str
return oo;
}

static inline void
init_open_stateid(struct nfs4_ol_stateid *stp, struct nfs4_file *fp, struct nfsd4_open *open) {
static inline __be32 init_open_stateid(struct nfs4_ol_stateid *stp, struct nfs4_file *fp, struct nfsd4_open *open) {
struct nfs4_openowner *oo = open->op_openowner;
struct nfs4_client *clp = oo->oo_owner.so_client;
__be32 status;

init_stid(&stp->st_stid, clp, NFS4_OPEN_STID);
status = init_stid(&stp->st_stid, clp, NFS4_OPEN_STID);
if (status)
return status;
INIT_LIST_HEAD(&stp->st_lockowners);
list_add(&stp->st_perstateowner, &oo->oo_owner.so_stateids);
list_add(&stp->st_perfile, &fp->fi_stateids);
Expand All @@ -2360,6 +2375,7 @@ init_open_stateid(struct nfs4_ol_stateid *stp, struct nfs4_file *fp, struct nfsd
&stp->st_access_bmap);
__set_bit(open->op_share_deny, &stp->st_deny_bmap);
stp->st_openstp = NULL;
return nfs_ok;
}

static void
Expand Down Expand Up @@ -2949,7 +2965,11 @@ nfsd4_process_open2(struct svc_rqst *rqstp, struct svc_fh *current_fh, struct nf
status = nfs4_new_open(rqstp, &stp, fp, current_fh, open);
if (status)
goto out;
init_open_stateid(stp, fp, open);
status = init_open_stateid(stp, fp, open);
if (status) {
release_open_stateid(stp);
goto out;
}
status = nfsd4_truncate(rqstp, current_fh, open);
if (status) {
release_open_stateid(stp);
Expand Down Expand Up @@ -3824,11 +3844,16 @@ alloc_init_lock_stateid(struct nfs4_lockowner *lo, struct nfs4_file *fp, struct
{
struct nfs4_ol_stateid *stp;
struct nfs4_client *clp = lo->lo_owner.so_client;
__be32 status;

stp = nfs4_alloc_stateid();
if (stp == NULL)
goto out;
init_stid(&stp->st_stid, clp, NFS4_LOCK_STID);
return NULL;
status = init_stid(&stp->st_stid, clp, NFS4_LOCK_STID);
if (status) {
free_generic_stateid(stp);
return NULL;
}
list_add(&stp->st_perfile, &fp->fi_stateids);
list_add(&stp->st_perstateowner, &lo->lo_owner.so_stateids);
stp->st_stateowner = &lo->lo_owner;
Expand All @@ -3837,8 +3862,6 @@ alloc_init_lock_stateid(struct nfs4_lockowner *lo, struct nfs4_file *fp, struct
stp->st_access_bmap = 0;
stp->st_deny_bmap = open_stp->st_deny_bmap;
stp->st_openstp = open_stp;

out:
return stp;
}

Expand Down Expand Up @@ -4386,8 +4409,7 @@ nfs4_state_init(void)
for (i = 0; i < OPEN_OWNER_HASH_SIZE; i++) {
INIT_LIST_HEAD(&open_ownerstr_hashtbl[i]);
}
for (i = 0; i < STATEID_HASH_SIZE; i++)
INIT_LIST_HEAD(&stateid_hashtbl[i]);
idr_init(&stateids);
for (i = 0; i < LOCK_HASH_SIZE; i++) {
INIT_LIST_HEAD(&lock_ownerstr_hashtbl[i]);
}
Expand Down
1 change: 0 additions & 1 deletion fs/nfsd/state.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -79,7 +79,6 @@ struct nfs4_stid {
/* For an open stateid kept around *only* to process close replays: */
#define NFS4_CLOSED_STID 8
unsigned char sc_type;
struct list_head sc_hash;
stateid_t sc_stateid;
struct nfs4_client *sc_client;
};
Expand Down

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