Commit 950e0118 authored by Trond Myklebust's avatar Trond Myklebust Committed by J. Bruce Fields
Browse files

nfsd: Protect addition to the file_hashtbl 



Current code depends on the client_mutex to guarantee a single struct
nfs4_file per inode in the file_hashtbl and make addition atomic with
respect to lookup.  Rely instead on the state_Lock, to make it easier to
stop taking the client_mutex here later.

To prevent an i_lock/state_lock inversion, change nfsd4_init_file to
use ihold instead if igrab. That's also more efficient anyway as we
definitely hold a reference to the inode at that point.

Signed-off-by: default avatarTrond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: default avatarJeff Layton <jlayton@primarydata.com>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarJ. Bruce Fields <bfields@redhat.com>
parent 7e6a72e5

fs/nfsd/nfs4state.c

+37 −12
Original line number Diff line number Diff line
@@ -2611,17 +2611,18 @@ static void nfsd4_init_file(struct nfs4_file *fp, struct inode *ino) 
{

	unsigned int hashval = file_hashval(ino);



	lockdep_assert_held(&state_lock);



	atomic_set(&fp->fi_ref, 1);

	INIT_LIST_HEAD(&fp->fi_stateids);

	INIT_LIST_HEAD(&fp->fi_delegations);

	fp->fi_inode = igrab(ino);

	ihold(ino);

	fp->fi_inode = ino;

	fp->fi_had_conflict = false;

	fp->fi_lease = NULL;

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

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

	spin_lock(&state_lock);

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

	spin_unlock(&state_lock);

}



void
@@ -2787,21 +2788,47 @@ find_openstateowner_str(unsigned int hashval, struct nfsd4_open *open, 


/* search file_hashtbl[] for file */

static struct nfs4_file *

find_file(struct inode *ino)

find_file_locked(struct inode *ino)

{

	unsigned int hashval = file_hashval(ino);

	struct nfs4_file *fp;



	spin_lock(&state_lock);

	lockdep_assert_held(&state_lock);



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

		if (fp->fi_inode == ino) {

			get_nfs4_file(fp);

			return fp;

		}

	}

	return NULL;

}



static struct nfs4_file *

find_file(struct inode *ino)

{

	struct nfs4_file *fp;



	spin_lock(&state_lock);

	fp = find_file_locked(ino);

	spin_unlock(&state_lock);

	return fp;

}



static struct nfs4_file *

find_or_add_file(struct inode *ino, struct nfs4_file *new)

{

	struct nfs4_file *fp;



	spin_lock(&state_lock);

	fp = find_file_locked(ino);

	if (fp == NULL) {

		nfsd4_init_file(new, ino);

		fp = new;

	}

	spin_unlock(&state_lock);

	return NULL;



	return fp;

}



/*
@@ -3325,21 +3352,19 @@ 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_file(ino);

	if (fp) {

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

	if (fp != open->op_file) {

		if ((status = nfs4_check_open(fp, open, &stp)))

			goto out;

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

		if (status)

			goto out;

	} else {

		open->op_file = NULL;

		status = nfserr_bad_stateid;

		if (nfsd4_is_deleg_cur(open))

			goto out;

		status = nfserr_jukebox;

		fp = open->op_file;

		open->op_file = NULL;

		nfsd4_init_file(fp, ino);

	}



	/*

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