Commit 689827cd authored by Trond Myklebust's avatar Trond Myklebust Committed by J. Bruce Fields
Browse files

nfsd: convert file cache to use over/underflow safe refcount 



Use the 'refcount_t' type instead of 'atomic_t' for improved
refcounting safety.

Signed-off-by: default avatarTrond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: default avatarJ. Bruce Fields <bfields@redhat.com>
parent c1928559

fs/nfsd/filecache.c

+11 −12
Original line number Diff line number Diff line
@@ -100,7 +100,7 @@ nfsd_file_mark_free(struct fsnotify_mark *mark) 
static struct nfsd_file_mark *

nfsd_file_mark_get(struct nfsd_file_mark *nfm)

{

	if (!atomic_inc_not_zero(&nfm->nfm_ref))

	if (!refcount_inc_not_zero(&nfm->nfm_ref))

		return NULL;

	return nfm;

}
@@ -108,8 +108,7 @@ nfsd_file_mark_get(struct nfsd_file_mark *nfm) 
static void

nfsd_file_mark_put(struct nfsd_file_mark *nfm)

{

	if (atomic_dec_and_test(&nfm->nfm_ref)) {



	if (refcount_dec_and_test(&nfm->nfm_ref)) {

		fsnotify_destroy_mark(&nfm->nfm_mark, nfsd_file_fsnotify_group);

		fsnotify_put_mark(&nfm->nfm_mark);

	}
@@ -148,7 +147,7 @@ nfsd_file_mark_find_or_create(struct nfsd_file *nf) 
			return NULL;

		fsnotify_init_mark(&new->nfm_mark, nfsd_file_fsnotify_group);

		new->nfm_mark.mask = FS_ATTRIB|FS_DELETE_SELF;

		atomic_set(&new->nfm_ref, 1);

		refcount_set(&new->nfm_ref, 1);



		err = fsnotify_add_inode_mark(&new->nfm_mark, inode, 0);
@@ -186,7 +185,7 @@ nfsd_file_alloc(struct inode *inode, unsigned int may, unsigned int hashval, 
		nf->nf_flags = 0;

		nf->nf_inode = inode;

		nf->nf_hashval = hashval;

		atomic_set(&nf->nf_ref, 1);

		refcount_set(&nf->nf_ref, 1);

		nf->nf_may = may & NFSD_FILE_MAY_MASK;

		if (may & NFSD_MAY_NOT_BREAK_LEASE) {

			if (may & NFSD_MAY_WRITE)
@@ -280,7 +279,7 @@ nfsd_file_unhash_and_release_locked(struct nfsd_file *nf, struct list_head *disp 
	if (!nfsd_file_unhash(nf))

		return false;

	/* keep final reference for nfsd_file_lru_dispose */

	if (atomic_add_unless(&nf->nf_ref, -1, 1))

	if (refcount_dec_not_one(&nf->nf_ref))

		return true;



	list_add(&nf->nf_lru, dispose);
@@ -292,7 +291,7 @@ nfsd_file_put_noref(struct nfsd_file *nf) 
{

	trace_nfsd_file_put(nf);



	if (atomic_dec_and_test(&nf->nf_ref)) {

	if (refcount_dec_and_test(&nf->nf_ref)) {

		WARN_ON(test_bit(NFSD_FILE_HASHED, &nf->nf_flags));

		nfsd_file_free(nf);

	}
@@ -304,7 +303,7 @@ nfsd_file_put(struct nfsd_file *nf) 
	bool is_hashed;



	set_bit(NFSD_FILE_REFERENCED, &nf->nf_flags);

	if (atomic_read(&nf->nf_ref) > 2 || !nf->nf_file) {

	if (refcount_read(&nf->nf_ref) > 2 || !nf->nf_file) {

		nfsd_file_put_noref(nf);

		return;

	}
@@ -321,7 +320,7 @@ nfsd_file_put(struct nfsd_file *nf) 
struct nfsd_file *

nfsd_file_get(struct nfsd_file *nf)

{

	if (likely(atomic_inc_not_zero(&nf->nf_ref)))

	if (likely(refcount_inc_not_zero(&nf->nf_ref)))

		return nf;

	return NULL;

}
@@ -347,7 +346,7 @@ nfsd_file_dispose_list_sync(struct list_head *dispose) 
	while(!list_empty(dispose)) {

		nf = list_first_entry(dispose, struct nfsd_file, nf_lru);

		list_del(&nf->nf_lru);

		if (!atomic_dec_and_test(&nf->nf_ref))

		if (!refcount_dec_and_test(&nf->nf_ref))

			continue;

		if (nfsd_file_free(nf))

			flush = true;
@@ -430,7 +429,7 @@ nfsd_file_lru_cb(struct list_head *item, struct list_lru_one *lru, 
	 * counter. Here we check the counter and then test and clear the flag.

	 * That order is deliberate to ensure that we can do this locklessly.

	 */

	if (atomic_read(&nf->nf_ref) > 1)

	if (refcount_read(&nf->nf_ref) > 1)

		goto out_skip;



	/*
@@ -1019,7 +1018,7 @@ out: 
open_file:

	nf = new;

	/* Take reference for the hashtable */

	atomic_inc(&nf->nf_ref);

	refcount_inc(&nf->nf_ref);

	__set_bit(NFSD_FILE_HASHED, &nf->nf_flags);

	__set_bit(NFSD_FILE_PENDING, &nf->nf_flags);

	list_lru_add(&nfsd_file_lru, &nf->nf_lru);

fs/nfsd/filecache.h

+2 −2
Original line number Diff line number Diff line
@@ -19,7 +19,7 @@ 
 */

struct nfsd_file_mark {

	struct fsnotify_mark	nfm_mark;

	atomic_t		nfm_ref;

	refcount_t		nfm_ref;

};



/*
@@ -43,7 +43,7 @@ struct nfsd_file { 
	unsigned long		nf_flags;

	struct inode		*nf_inode;

	unsigned int		nf_hashval;

	atomic_t		nf_ref;

	refcount_t		nf_ref;

	unsigned char		nf_may;

	struct nfsd_file_mark	*nf_mark;

	struct rw_semaphore	nf_rwsem;

fs/nfsd/trace.h

+2 −2
Original line number Diff line number Diff line
@@ -201,7 +201,7 @@ DECLARE_EVENT_CLASS(nfsd_file_class, 
	TP_fast_assign(

		__entry->nf_hashval = nf->nf_hashval;

		__entry->nf_inode = nf->nf_inode;

		__entry->nf_ref = atomic_read(&nf->nf_ref);

		__entry->nf_ref = refcount_read(&nf->nf_ref);

		__entry->nf_flags = nf->nf_flags;

		__entry->nf_may = nf->nf_may;

		__entry->nf_file = nf->nf_file;
@@ -250,7 +250,7 @@ TRACE_EVENT(nfsd_file_acquire, 
		__entry->hash = hash;

		__entry->inode = inode;

		__entry->may_flags = may_flags;

		__entry->nf_ref = nf ? atomic_read(&nf->nf_ref) : 0;

		__entry->nf_ref = nf ? refcount_read(&nf->nf_ref) : 0;

		__entry->nf_flags = nf ? nf->nf_flags : 0;

		__entry->nf_may = nf ? nf->nf_may : 0;

		__entry->nf_file = nf ? nf->nf_file : NULL;

CRA Git | Maintained and supported by SUSTech CRA and CCSE