Commit a0ce4837 authored by J. Bruce Fields's avatar J. Bruce Fields Committed by Chuck Lever
Browse files

nfsd: track filehandle aliasing in nfs4_files 



It's unusual but possible for multiple filehandles to point to the same
file.  In that case, we may end up with multiple nfs4_files referencing
the same inode.

For delegation purposes it will turn out to be useful to flag those
cases.

Signed-off-by: default avatarJ. Bruce Fields <bfields@redhat.com>
Signed-off-by: default avatarChuck Lever <chuck.lever@oracle.com>
parent f9b60e22

fs/nfsd/nfs4state.c

+28 −9
Original line number Diff line number Diff line
@@ -4086,6 +4086,8 @@ static void nfsd4_init_file(struct svc_fh *fh, unsigned int hashval, 
	fp->fi_share_deny = 0;

	memset(fp->fi_fds, 0, sizeof(fp->fi_fds));

	memset(fp->fi_access, 0, sizeof(fp->fi_access));

	fp->fi_aliased = false;

	fp->fi_inode = d_inode(fh->fh_dentry);

#ifdef CONFIG_NFSD_PNFS

	INIT_LIST_HEAD(&fp->fi_lo_states);

	atomic_set(&fp->fi_lo_recalls, 0);
@@ -4438,6 +4440,31 @@ find_file_locked(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)

{

	struct nfs4_file *fp;

	struct nfs4_file *ret = NULL;

	bool alias_found = false;



	spin_lock(&state_lock);

	hlist_for_each_entry_rcu(fp, &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 (likely(ret == NULL)) {

		nfsd4_init_file(fh, hashval, new);

		new->fi_aliased = alias_found;

		ret = new;

	}

	spin_unlock(&state_lock);

	return ret;

}



static struct nfs4_file * find_file(struct svc_fh *fh)

{

	struct nfs4_file *fp;
@@ -4461,15 +4488,7 @@ find_or_add_file(struct nfs4_file *new, struct svc_fh *fh) 
	if (fp)

		return fp;



	spin_lock(&state_lock);

	fp = find_file_locked(fh, hashval);

	if (likely(fp == NULL)) {

		nfsd4_init_file(fh, hashval, new);

		fp = new;

	}

	spin_unlock(&state_lock);



	return fp;

	return insert_file(new, fh, hashval);

}



/*

fs/nfsd/state.h

+2 −0
Original line number Diff line number Diff line
@@ -516,6 +516,8 @@ struct nfs4_clnt_odstate { 
 */

struct nfs4_file {

	refcount_t		fi_ref;

	struct inode *		fi_inode;

	bool			fi_aliased;

	spinlock_t		fi_lock;

	struct hlist_node       fi_hash;	/* hash on fi_fhandle */

	struct list_head        fi_stateids;