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Commit 8b671b80 authored by J. Bruce Fields's avatar J. Bruce Fields
Browse files

nfsd4: remove use of mutex for file_hashtable 



As part of reducing the scope of the client_mutex, and in order to
remove the need for mutexes from the callback code (so that callbacks
can be done as asynchronous rpc calls), move manipulations of the
file_hashtable under the recall_lock.

Update the relevant comments while we're here.

Signed-off-by: default avatarJ. Bruce Fields <bfields@citi.umich.edu>
Cc: Alexandros Batsakis <batsakis@netapp.com>
Reviewed-by: default avatarBenny Halevy <bhalevy@panasas.com>
parent d7fdcfe0

fs/nfsd/nfs4callback.c

+0 −2
Original line number Diff line number Diff line
@@ -491,8 +491,6 @@ nfsd4_cb_recall(struct nfs4_delegation *dp) 
	 * or deleg_return.

	 */

	put_nfs4_client(clp);

	nfs4_lock_state();

	nfs4_put_delegation(dp);

	nfs4_unlock_state();

	return;

}

fs/nfsd/nfs4state.c

+23 −24
Original line number Diff line number Diff line
@@ -78,14 +78,18 @@ static struct nfs4_delegation * find_delegation_stateid(struct inode *ino, state 
static char user_recovery_dirname[PATH_MAX] = "/var/lib/nfs/v4recovery";

static void nfs4_set_recdir(char *recdir);



/* Locking:

 *

 * client_mutex:

 * 	protects clientid_hashtbl[], clientstr_hashtbl[],

 * 	unconfstr_hashtbl[], uncofid_hashtbl[].

 */

/* Locking: */



/* Currently used for almost all code touching nfsv4 state: */

static DEFINE_MUTEX(client_mutex);



/*

 * Currently used for the del_recall_lru and file hash table.  In an

 * effort to decrease the scope of the client_mutex, this spinlock may

 * eventually cover more:

 */

static DEFINE_SPINLOCK(recall_lock);



static struct kmem_cache *stateowner_slab = NULL;

static struct kmem_cache *file_slab = NULL;

static struct kmem_cache *stateid_slab = NULL;
@@ -116,33 +120,23 @@ opaque_hashval(const void *ptr, int nbytes) 
	return x;

}



/*

 * Delegation state

 */



/* recall_lock protects the del_recall_lru */

static DEFINE_SPINLOCK(recall_lock);

static struct list_head del_recall_lru;



static void

free_nfs4_file(struct kref *kref)

{

	struct nfs4_file *fp = container_of(kref, struct nfs4_file, fi_ref);

	list_del(&fp->fi_hash);

	iput(fp->fi_inode);

	kmem_cache_free(file_slab, fp);

}



static inline void

put_nfs4_file(struct nfs4_file *fi)

{

	kref_put(&fi->fi_ref, free_nfs4_file);

	if (atomic_dec_and_lock(&fi->fi_ref, &recall_lock)) {

		list_del(&fi->fi_hash);

		spin_unlock(&recall_lock);

		iput(fi->fi_inode);

		kmem_cache_free(file_slab, fi);

	}

}



static inline void

get_nfs4_file(struct nfs4_file *fi)

{

	kref_get(&fi->fi_ref);

	atomic_inc(&fi->fi_ref);

}



static int num_delegations;
@@ -1000,11 +994,13 @@ alloc_init_file(struct inode *ino) 


	fp = kmem_cache_alloc(file_slab, GFP_KERNEL);

	if (fp) {

		kref_init(&fp->fi_ref);

		atomic_set(&fp->fi_ref, 1);

		INIT_LIST_HEAD(&fp->fi_hash);

		INIT_LIST_HEAD(&fp->fi_stateids);

		INIT_LIST_HEAD(&fp->fi_delegations);

		spin_lock(&recall_lock);

		list_add(&fp->fi_hash, &file_hashtbl[hashval]);

		spin_unlock(&recall_lock);

		fp->fi_inode = igrab(ino);

		fp->fi_id = current_fileid++;

		fp->fi_had_conflict = false;
@@ -1177,12 +1173,15 @@ find_file(struct inode *ino) 
	unsigned int hashval = file_hashval(ino);

	struct nfs4_file *fp;



	spin_lock(&recall_lock);

	list_for_each_entry(fp, &file_hashtbl[hashval], fi_hash) {

		if (fp->fi_inode == ino) {

			get_nfs4_file(fp);

			spin_unlock(&recall_lock);

			return fp;

		}

	}

	spin_unlock(&recall_lock);

	return NULL;

}

include/linux/nfsd/state.h

+1 −1
Original line number Diff line number Diff line
@@ -214,7 +214,7 @@ struct nfs4_stateowner { 
*      share_acces, share_deny on the file.

*/

struct nfs4_file {

	struct kref		fi_ref;

	atomic_t		fi_ref;

	struct list_head        fi_hash;    /* hash by "struct inode *" */

	struct list_head        fi_stateids;

	struct list_head	fi_delegations;