Commit 9270fc51 authored by Chuck Lever's avatar Chuck Lever
Browse files

NFSD: Clean up find_or_add_file() 



Remove the call to find_file_locked() in insert_nfs4_file(). Tracing
shows that over 99% of these calls return NULL. Thus it is not worth
the expense of the extra bucket list traversal. insert_file() already
deals correctly with the case where the item is already in the hash
bucket.

Since nfsd4_file_hash_insert() is now just a wrapper around
insert_file(), move the meat of insert_file() into
nfsd4_file_hash_insert() and get rid of it.

Signed-off-by: default avatarChuck Lever <chuck.lever@oracle.com>
Reviewed-by: default avatarNeilBrown <neilb@suse.de>
parent 3341678f

fs/nfsd/nfs4state.c

+28 −36
Original line number Diff line number Diff line
@@ -4698,24 +4698,42 @@ find_file_locked(const struct svc_fh *fh, unsigned int hashval) 
	return NULL;

}



static struct nfs4_file *insert_file(struct nfs4_file *new, struct svc_fh *fh,

				     unsigned int hashval)

static struct nfs4_file * find_file(struct svc_fh *fh)

{

	struct nfs4_file *fp;

	unsigned int hashval = file_hashval(fh);



	rcu_read_lock();

	fp = find_file_locked(fh, hashval);

	rcu_read_unlock();

	return fp;

}



/*

 * On hash insertion, identify entries with the same inode but

 * distinct filehandles. They will all be in the same hash bucket

 * because nfs4_file's are hashed by the address in the fi_inode

 * field.

 */

static noinline_for_stack struct nfs4_file *

nfsd4_file_hash_insert(struct nfs4_file *new, const struct svc_fh *fhp)

{

	unsigned int hashval = file_hashval(fhp);

	struct nfs4_file *ret = NULL;

	bool alias_found = false;

	struct nfs4_file *fi;



	spin_lock(&state_lock);

	hlist_for_each_entry_rcu(fp, &file_hashtbl[hashval], fi_hash,

	hlist_for_each_entry_rcu(fi, &file_hashtbl[hashval], fi_hash,

				 lockdep_is_held(&state_lock)) {

		if (fh_match(&fp->fi_fhandle, &fh->fh_handle)) {

			if (refcount_inc_not_zero(&fp->fi_ref))

				ret = fp;

		} else if (d_inode(fh->fh_dentry) == fp->fi_inode)

			fp->fi_aliased = alias_found = true;

		if (fh_match(&fi->fi_fhandle, &fhp->fh_handle)) {

			if (refcount_inc_not_zero(&fi->fi_ref))

				ret = fi;

		} else if (d_inode(fhp->fh_dentry) == fi->fi_inode)

			fi->fi_aliased = alias_found = true;

	}

	if (likely(ret == NULL)) {

		nfsd4_file_init(fh, new);

		nfsd4_file_init(fhp, new);

		hlist_add_head_rcu(&new->fi_hash, &file_hashtbl[hashval]);

		new->fi_aliased = alias_found;

		ret = new;
@@ -4724,32 +4742,6 @@ static struct nfs4_file *insert_file(struct nfs4_file *new, struct svc_fh *fh, 
	return ret;

}



static struct nfs4_file * find_file(struct svc_fh *fh)

{

	struct nfs4_file *fp;

	unsigned int hashval = file_hashval(fh);



	rcu_read_lock();

	fp = find_file_locked(fh, hashval);

	rcu_read_unlock();

	return fp;

}



static struct nfs4_file *

find_or_add_file(struct nfs4_file *new, struct svc_fh *fh)

{

	struct nfs4_file *fp;

	unsigned int hashval = file_hashval(fh);



	rcu_read_lock();

	fp = find_file_locked(fh, hashval);

	rcu_read_unlock();

	if (fp)

		return fp;



	return insert_file(new, fh, hashval);

}



static noinline_for_stack void nfsd4_file_hash_remove(struct nfs4_file *fi)

{

	hlist_del_rcu(&fi->fi_hash);
@@ -5641,7 +5633,7 @@ nfsd4_process_open2(struct svc_rqst *rqstp, struct svc_fh *current_fh, struct nf 
	 * and check for delegations in the process of being recalled.

	 * If not found, create the nfs4_file struct

	 */

	fp = find_or_add_file(open->op_file, current_fh);

	fp = nfsd4_file_hash_insert(open->op_file, current_fh);

	if (fp != open->op_file) {

		status = nfs4_check_deleg(cl, open, &dp);

		if (status)