Commit 4d1ea845 authored by Chuck Lever's avatar Chuck Lever
Browse files

NFSD: Add an NFSD_FILE_GC flag to enable nfsd_file garbage collection 

NFSv4 operations manage the lifetime of nfsd_file items they use by
means of NFSv4 OPEN and CLOSE. Hence there's no need for them to be
garbage collected.

Introduce a mechanism to enable garbage collection for nfsd_file
items used only by NFSv2/3 callers.

Note that the change in nfsd_file_put() ensures that both CLOSE and
DELEGRETURN will actually close out and free an nfsd_file on last
reference of a non-garbage-collected file.

Link: https://bugzilla.linux-nfs.org/show_bug.cgi?id=394


Suggested-by: default avatarTrond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: default avatarChuck Lever <chuck.lever@oracle.com>
Tested-by: default avatarJeff Layton <jlayton@kernel.org>
Reviewed-by: default avatarNeilBrown <neilb@suse.de>
Reviewed-by: default avatarJeff Layton <jlayton@kernel.org>
parent dcf3f809

fs/nfsd/filecache.c

+55 −8
Original line number Diff line number Diff line
@@ -63,6 +63,7 @@ struct nfsd_file_lookup_key { 
	struct net			*net;

	const struct cred		*cred;

	unsigned char			need;

	bool				gc;

	enum nfsd_file_lookup_type	type;

};
@@ -162,6 +163,8 @@ static int nfsd_file_obj_cmpfn(struct rhashtable_compare_arg *arg, 
			return 1;

		if (!nfsd_match_cred(nf->nf_cred, key->cred))

			return 1;

		if (!!test_bit(NFSD_FILE_GC, &nf->nf_flags) != key->gc)

			return 1;

		if (test_bit(NFSD_FILE_HASHED, &nf->nf_flags) == 0)

			return 1;

		break;
@@ -297,6 +300,8 @@ nfsd_file_alloc(struct nfsd_file_lookup_key *key, unsigned int may) 
		nf->nf_flags = 0;

		__set_bit(NFSD_FILE_HASHED, &nf->nf_flags);

		__set_bit(NFSD_FILE_PENDING, &nf->nf_flags);

		if (key->gc)

			__set_bit(NFSD_FILE_GC, &nf->nf_flags);

		nf->nf_inode = key->inode;

		/* nf_ref is pre-incremented for hash table */

		refcount_set(&nf->nf_ref, 2);
@@ -428,16 +433,27 @@ nfsd_file_put_noref(struct nfsd_file *nf) 
	}

}



static void

nfsd_file_unhash_and_put(struct nfsd_file *nf)

{

	if (nfsd_file_unhash(nf))

		nfsd_file_put_noref(nf);

}



void

nfsd_file_put(struct nfsd_file *nf)

{

	might_sleep();



	if (test_bit(NFSD_FILE_GC, &nf->nf_flags))

		nfsd_file_lru_add(nf);

	if (test_bit(NFSD_FILE_HASHED, &nf->nf_flags) == 0) {

	else if (refcount_read(&nf->nf_ref) == 2)

		nfsd_file_unhash_and_put(nf);



	if (!test_bit(NFSD_FILE_HASHED, &nf->nf_flags)) {

		nfsd_file_flush(nf);

		nfsd_file_put_noref(nf);

	} else if (nf->nf_file) {

	} else if (nf->nf_file && test_bit(NFSD_FILE_GC, &nf->nf_flags)) {

		nfsd_file_put_noref(nf);

		nfsd_file_schedule_laundrette();

	} else
@@ -1016,12 +1032,14 @@ nfsd_file_is_cached(struct inode *inode) 


static __be32

nfsd_file_do_acquire(struct svc_rqst *rqstp, struct svc_fh *fhp,

		     unsigned int may_flags, struct nfsd_file **pnf, bool open)

		     unsigned int may_flags, struct nfsd_file **pnf,

		     bool open, bool want_gc)

{

	struct nfsd_file_lookup_key key = {

		.type	= NFSD_FILE_KEY_FULL,

		.need	= may_flags & NFSD_FILE_MAY_MASK,

		.net	= SVC_NET(rqstp),

		.gc	= want_gc,

	};

	bool open_retry = true;

	struct nfsd_file *nf;
@@ -1117,14 +1135,35 @@ nfsd_file_do_acquire(struct svc_rqst *rqstp, struct svc_fh *fhp, 
	 * then unhash.

	 */

	if (status != nfs_ok || key.inode->i_nlink == 0)

		if (nfsd_file_unhash(nf))

			nfsd_file_put_noref(nf);

		nfsd_file_unhash_and_put(nf);

	clear_bit_unlock(NFSD_FILE_PENDING, &nf->nf_flags);

	smp_mb__after_atomic();

	wake_up_bit(&nf->nf_flags, NFSD_FILE_PENDING);

	goto out;

}



/**

 * nfsd_file_acquire_gc - Get a struct nfsd_file with an open file

 * @rqstp: the RPC transaction being executed

 * @fhp: the NFS filehandle of the file to be opened

 * @may_flags: NFSD_MAY_ settings for the file

 * @pnf: OUT: new or found "struct nfsd_file" object

 *

 * The nfsd_file object returned by this API is reference-counted

 * and garbage-collected. The object is retained for a few

 * seconds after the final nfsd_file_put() in case the caller

 * wants to re-use it.

 *

 * Returns nfs_ok and sets @pnf on success; otherwise an nfsstat in

 * network byte order is returned.

 */

__be32

nfsd_file_acquire_gc(struct svc_rqst *rqstp, struct svc_fh *fhp,

		     unsigned int may_flags, struct nfsd_file **pnf)

{

	return nfsd_file_do_acquire(rqstp, fhp, may_flags, pnf, true, true);

}



/**

 * nfsd_file_acquire - Get a struct nfsd_file with an open file

 * @rqstp: the RPC transaction being executed
@@ -1132,6 +1171,10 @@ nfsd_file_do_acquire(struct svc_rqst *rqstp, struct svc_fh *fhp, 
 * @may_flags: NFSD_MAY_ settings for the file

 * @pnf: OUT: new or found "struct nfsd_file" object

 *

 * The nfsd_file_object returned by this API is reference-counted

 * but not garbage-collected. The object is unhashed after the

 * final nfsd_file_put().

 *

 * Returns nfs_ok and sets @pnf on success; otherwise an nfsstat in

 * network byte order is returned.

 */
@@ -1139,7 +1182,7 @@ __be32 
nfsd_file_acquire(struct svc_rqst *rqstp, struct svc_fh *fhp,

		  unsigned int may_flags, struct nfsd_file **pnf)

{

	return nfsd_file_do_acquire(rqstp, fhp, may_flags, pnf, true);

	return nfsd_file_do_acquire(rqstp, fhp, may_flags, pnf, true, false);

}



/**
@@ -1149,6 +1192,10 @@ nfsd_file_acquire(struct svc_rqst *rqstp, struct svc_fh *fhp, 
 * @may_flags: NFSD_MAY_ settings for the file

 * @pnf: OUT: new or found "struct nfsd_file" object

 *

 * The nfsd_file_object returned by this API is reference-counted

 * but not garbage-collected. The object is released immediately

 * one RCU grace period after the final nfsd_file_put().

 *

 * Returns nfs_ok and sets @pnf on success; otherwise an nfsstat in

 * network byte order is returned.

 */
@@ -1156,7 +1203,7 @@ __be32 
nfsd_file_create(struct svc_rqst *rqstp, struct svc_fh *fhp,

		 unsigned int may_flags, struct nfsd_file **pnf)

{

	return nfsd_file_do_acquire(rqstp, fhp, may_flags, pnf, false);

	return nfsd_file_do_acquire(rqstp, fhp, may_flags, pnf, false, false);

}



/*

fs/nfsd/filecache.h

+3 −0
Original line number Diff line number Diff line
@@ -38,6 +38,7 @@ struct nfsd_file { 
#define NFSD_FILE_HASHED	(0)

#define NFSD_FILE_PENDING	(1)

#define NFSD_FILE_REFERENCED	(2)

#define NFSD_FILE_GC		(3)

	unsigned long		nf_flags;

	struct inode		*nf_inode;	/* don't deref */

	refcount_t		nf_ref;
@@ -55,6 +56,8 @@ void nfsd_file_put(struct nfsd_file *nf); 
struct nfsd_file *nfsd_file_get(struct nfsd_file *nf);

void nfsd_file_close_inode_sync(struct inode *inode);

bool nfsd_file_is_cached(struct inode *inode);

__be32 nfsd_file_acquire_gc(struct svc_rqst *rqstp, struct svc_fh *fhp,

		  unsigned int may_flags, struct nfsd_file **nfp);

__be32 nfsd_file_acquire(struct svc_rqst *rqstp, struct svc_fh *fhp,

		  unsigned int may_flags, struct nfsd_file **nfp);

__be32 nfsd_file_create(struct svc_rqst *rqstp, struct svc_fh *fhp,

fs/nfsd/nfs3proc.c

+2 −2
Original line number Diff line number Diff line
@@ -772,7 +772,7 @@ nfsd3_proc_commit(struct svc_rqst *rqstp) 
				(unsigned long long) argp->offset);



	fh_copy(&resp->fh, &argp->fh);

	resp->status = nfsd_file_acquire(rqstp, &resp->fh, NFSD_MAY_WRITE |

	resp->status = nfsd_file_acquire_gc(rqstp, &resp->fh, NFSD_MAY_WRITE |

					    NFSD_MAY_NOT_BREAK_LEASE, &nf);

	if (resp->status)

		goto out;

fs/nfsd/trace.h

+2 −1
Original line number Diff line number Diff line
@@ -817,7 +817,8 @@ DEFINE_CLID_EVENT(confirmed_r); 
	__print_flags(val, "|",						\

		{ 1 << NFSD_FILE_HASHED,	"HASHED" },		\

		{ 1 << NFSD_FILE_PENDING,	"PENDING" },		\

		{ 1 << NFSD_FILE_REFERENCED,	"REFERENCED"})

		{ 1 << NFSD_FILE_REFERENCED,	"REFERENCED"},		\

		{ 1 << NFSD_FILE_GC,		"GC"})



DECLARE_EVENT_CLASS(nfsd_file_class,

	TP_PROTO(struct nfsd_file *nf),

fs/nfsd/vfs.c

+2 −2
Original line number Diff line number Diff line
@@ -1148,7 +1148,7 @@ __be32 nfsd_read(struct svc_rqst *rqstp, struct svc_fh *fhp, 
	__be32 err;



	trace_nfsd_read_start(rqstp, fhp, offset, *count);

	err = nfsd_file_acquire(rqstp, fhp, NFSD_MAY_READ, &nf);

	err = nfsd_file_acquire_gc(rqstp, fhp, NFSD_MAY_READ, &nf);

	if (err)

		return err;
@@ -1180,7 +1180,7 @@ nfsd_write(struct svc_rqst *rqstp, struct svc_fh *fhp, loff_t offset, 


	trace_nfsd_write_start(rqstp, fhp, offset, *cnt);



	err = nfsd_file_acquire(rqstp, fhp, NFSD_MAY_WRITE, &nf);

	err = nfsd_file_acquire_gc(rqstp, fhp, NFSD_MAY_WRITE, &nf);

	if (err)

		goto out;