Commit bc015cb8 authored by Steven Whitehouse's avatar Steven Whitehouse
Browse files

GFS2: Use RCU for glock hash table 



This has a number of advantages:

 - Reduces contention on the hash table lock
 - Makes the code smaller and simpler
 - Should speed up glock dumps when under load
 - Removes ref count changing in examine_bucket
 - No longer need hash chain lock in glock_put() in common case

There are some further changes which this enables and which
we may do in the future. One is to look at using SLAB_RCU,
and another is to look at using a per-cpu counter for the
per-sb glock counter, since that is touched twice in the
lifetime of each glock (but only used at umount time).

Signed-off-by: default avatarSteven Whitehouse <swhiteho@redhat.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
parent 2b1caf6e

fs/gfs2/glock.c

+147 −243
Original line number Diff line number Diff line
@@ -26,6 +26,9 @@ 
#include <linux/freezer.h>

#include <linux/workqueue.h>

#include <linux/jiffies.h>

#include <linux/rcupdate.h>

#include <linux/rculist_bl.h>

#include <linux/bit_spinlock.h>



#include "gfs2.h"

#include "incore.h"
@@ -41,10 +44,6 @@ 
#define CREATE_TRACE_POINTS

#include "trace_gfs2.h"



struct gfs2_gl_hash_bucket {

        struct hlist_head hb_list;

};



struct gfs2_glock_iter {

	int hash;			/* hash bucket index         */

	struct gfs2_sbd *sdp;		/* incore superblock         */
@@ -54,7 +53,6 @@ struct gfs2_glock_iter { 


typedef void (*glock_examiner) (struct gfs2_glock * gl);



static int gfs2_dump_lockstate(struct gfs2_sbd *sdp);

static int __dump_glock(struct seq_file *seq, const struct gfs2_glock *gl);

#define GLOCK_BUG_ON(gl,x) do { if (unlikely(x)) { __dump_glock(NULL, gl); BUG(); } } while(0)

static void do_xmote(struct gfs2_glock *gl, struct gfs2_holder *gh, unsigned int target);
@@ -70,57 +68,9 @@ static DEFINE_SPINLOCK(lru_lock); 
#define GFS2_GL_HASH_SIZE       (1 << GFS2_GL_HASH_SHIFT)

#define GFS2_GL_HASH_MASK       (GFS2_GL_HASH_SIZE - 1)



static struct gfs2_gl_hash_bucket gl_hash_table[GFS2_GL_HASH_SIZE];

static struct hlist_bl_head gl_hash_table[GFS2_GL_HASH_SIZE];

static struct dentry *gfs2_root;



/*

 * Despite what you might think, the numbers below are not arbitrary :-)

 * They are taken from the ipv4 routing hash code, which is well tested

 * and thus should be nearly optimal. Later on we might tweek the numbers

 * but for now this should be fine.

 *

 * The reason for putting the locks in a separate array from the list heads

 * is that we can have fewer locks than list heads and save memory. We use

 * the same hash function for both, but with a different hash mask.

 */

#if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK) || \

	defined(CONFIG_PROVE_LOCKING)



#ifdef CONFIG_LOCKDEP

# define GL_HASH_LOCK_SZ        256

#else

# if NR_CPUS >= 32

#  define GL_HASH_LOCK_SZ       4096

# elif NR_CPUS >= 16

#  define GL_HASH_LOCK_SZ       2048

# elif NR_CPUS >= 8

#  define GL_HASH_LOCK_SZ       1024

# elif NR_CPUS >= 4

#  define GL_HASH_LOCK_SZ       512

# else

#  define GL_HASH_LOCK_SZ       256

# endif

#endif



/* We never want more locks than chains */

#if GFS2_GL_HASH_SIZE < GL_HASH_LOCK_SZ

# undef GL_HASH_LOCK_SZ

# define GL_HASH_LOCK_SZ GFS2_GL_HASH_SIZE

#endif



static rwlock_t gl_hash_locks[GL_HASH_LOCK_SZ];



static inline rwlock_t *gl_lock_addr(unsigned int x)

{

	return &gl_hash_locks[x & (GL_HASH_LOCK_SZ-1)];

}

#else /* not SMP, so no spinlocks required */

static inline rwlock_t *gl_lock_addr(unsigned int x)

{

	return NULL;

}

#endif



/**

 * gl_hash() - Turn glock number into hash bucket number

 * @lock: The glock number
@@ -141,25 +91,30 @@ static unsigned int gl_hash(const struct gfs2_sbd *sdp, 
	return h;

}



/**

 * glock_free() - Perform a few checks and then release struct gfs2_glock

 * @gl: The glock to release

 *

 * Also calls lock module to release its internal structure for this glock.

 *

 */

static inline void spin_lock_bucket(unsigned int hash)

{

	struct hlist_bl_head *bl = &gl_hash_table[hash];

	bit_spin_lock(0, (unsigned long *)bl);

}



static void glock_free(struct gfs2_glock *gl)

static inline void spin_unlock_bucket(unsigned int hash)

{

	struct hlist_bl_head *bl = &gl_hash_table[hash];

	__bit_spin_unlock(0, (unsigned long *)bl);

}



void gfs2_glock_free(struct rcu_head *rcu)

{

	struct gfs2_glock *gl = container_of(rcu, struct gfs2_glock, gl_rcu);

	struct gfs2_sbd *sdp = gl->gl_sbd;

	struct address_space *mapping = gfs2_glock2aspace(gl);

	struct kmem_cache *cachep = gfs2_glock_cachep;



	GLOCK_BUG_ON(gl, mapping && mapping->nrpages);

	trace_gfs2_glock_put(gl);

	if (mapping)

		cachep = gfs2_glock_aspace_cachep;

	sdp->sd_lockstruct.ls_ops->lm_put_lock(cachep, gl);

	if (gl->gl_ops->go_flags & GLOF_ASPACE)

		kmem_cache_free(gfs2_glock_aspace_cachep, gl);

	else

		kmem_cache_free(gfs2_glock_cachep, gl);



	if (atomic_dec_and_test(&sdp->sd_glock_disposal))

		wake_up(&sdp->sd_glock_wait);

}



/**
@@ -185,35 +140,50 @@ static int demote_ok(const struct gfs2_glock *gl) 
{

	const struct gfs2_glock_operations *glops = gl->gl_ops;



	/* assert_spin_locked(&gl->gl_spin); */



	if (gl->gl_state == LM_ST_UNLOCKED)

		return 0;

	if (!list_empty(&gl->gl_holders))

	if (test_bit(GLF_LFLUSH, &gl->gl_flags))

		return 0;

	if ((gl->gl_name.ln_type != LM_TYPE_INODE) &&

	    !list_empty(&gl->gl_holders))

		return 0;

	if (glops->go_demote_ok)

		return glops->go_demote_ok(gl);

	return 1;

}





/**

 * gfs2_glock_schedule_for_reclaim - Add a glock to the reclaim list

 * __gfs2_glock_schedule_for_reclaim - Add a glock to the reclaim list

 * @gl: the glock

 *

 * If the glock is demotable, then we add it (or move it) to the end

 * of the glock LRU list.

 */



static void gfs2_glock_schedule_for_reclaim(struct gfs2_glock *gl)

static void __gfs2_glock_schedule_for_reclaim(struct gfs2_glock *gl)

{

	int may_reclaim;

	may_reclaim = (demote_ok(gl) &&

		       (atomic_read(&gl->gl_ref) == 1 ||

			(gl->gl_name.ln_type == LM_TYPE_INODE &&

			 atomic_read(&gl->gl_ref) <= 2)));

	if (demote_ok(gl)) {

		spin_lock(&lru_lock);

	if (list_empty(&gl->gl_lru) && may_reclaim) {

		list_add_tail(&gl->gl_lru, &lru_list);



		if (!list_empty(&gl->gl_lru))

			list_del_init(&gl->gl_lru);

		else

			atomic_inc(&lru_count);

	}



		list_add_tail(&gl->gl_lru, &lru_list);

		spin_unlock(&lru_lock);

	}

}



void gfs2_glock_schedule_for_reclaim(struct gfs2_glock *gl)

{

	spin_lock(&gl->gl_spin);

	__gfs2_glock_schedule_for_reclaim(gl);

	spin_unlock(&gl->gl_spin);

}



/**

 * gfs2_glock_put_nolock() - Decrement reference count on glock
@@ -227,7 +197,6 @@ void gfs2_glock_put_nolock(struct gfs2_glock *gl) 
{

	if (atomic_dec_and_test(&gl->gl_ref))

		GLOCK_BUG_ON(gl, 1);

	gfs2_glock_schedule_for_reclaim(gl);

}



/**
@@ -236,30 +205,26 @@ void gfs2_glock_put_nolock(struct gfs2_glock *gl) 
 *

 */



int gfs2_glock_put(struct gfs2_glock *gl)

void gfs2_glock_put(struct gfs2_glock *gl)

{

	int rv = 0;

	struct gfs2_sbd *sdp = gl->gl_sbd;

	struct address_space *mapping = gfs2_glock2aspace(gl);



	write_lock(gl_lock_addr(gl->gl_hash));

	if (atomic_dec_and_lock(&gl->gl_ref, &lru_lock)) {

		hlist_del(&gl->gl_list);

	if (atomic_dec_and_test(&gl->gl_ref)) {

		spin_lock_bucket(gl->gl_hash);

		hlist_bl_del_rcu(&gl->gl_list);

		spin_unlock_bucket(gl->gl_hash);

		spin_lock(&lru_lock);

		if (!list_empty(&gl->gl_lru)) {

			list_del_init(&gl->gl_lru);

			atomic_dec(&lru_count);

		}

		spin_unlock(&lru_lock);

		write_unlock(gl_lock_addr(gl->gl_hash));

		GLOCK_BUG_ON(gl, !list_empty(&gl->gl_holders));

		glock_free(gl);

		rv = 1;

		goto out;

		GLOCK_BUG_ON(gl, mapping && mapping->nrpages);

		trace_gfs2_glock_put(gl);

		sdp->sd_lockstruct.ls_ops->lm_put_lock(gl);

	}

	spin_lock(&gl->gl_spin);

	gfs2_glock_schedule_for_reclaim(gl);

	spin_unlock(&gl->gl_spin);

	write_unlock(gl_lock_addr(gl->gl_hash));

out:

	return rv;

}



/**
@@ -275,16 +240,14 @@ static struct gfs2_glock *search_bucket(unsigned int hash, 
					const struct lm_lockname *name)

{

	struct gfs2_glock *gl;

	struct hlist_node *h;

	struct hlist_bl_node *h;



	hlist_for_each_entry(gl, h, &gl_hash_table[hash].hb_list, gl_list) {

	hlist_bl_for_each_entry_rcu(gl, h, &gl_hash_table[hash], gl_list) {

		if (!lm_name_equal(&gl->gl_name, name))

			continue;

		if (gl->gl_sbd != sdp)

			continue;



		atomic_inc(&gl->gl_ref);



		if (atomic_inc_not_zero(&gl->gl_ref))

			return gl;

	}
@@ -743,10 +706,11 @@ int gfs2_glock_get(struct gfs2_sbd *sdp, u64 number, 
	struct gfs2_glock *gl, *tmp;

	unsigned int hash = gl_hash(sdp, &name);

	struct address_space *mapping;

	struct kmem_cache *cachep;



	read_lock(gl_lock_addr(hash));

	rcu_read_lock();

	gl = search_bucket(hash, sdp, &name);

	read_unlock(gl_lock_addr(hash));

	rcu_read_unlock();



	*glp = gl;

	if (gl)
@@ -755,9 +719,10 @@ int gfs2_glock_get(struct gfs2_sbd *sdp, u64 number, 
		return -ENOENT;



	if (glops->go_flags & GLOF_ASPACE)

		gl = kmem_cache_alloc(gfs2_glock_aspace_cachep, GFP_KERNEL);

		cachep = gfs2_glock_aspace_cachep;

	else

		gl = kmem_cache_alloc(gfs2_glock_cachep, GFP_KERNEL);

		cachep = gfs2_glock_cachep;

	gl = kmem_cache_alloc(cachep, GFP_KERNEL);

	if (!gl)

		return -ENOMEM;
@@ -790,15 +755,15 @@ int gfs2_glock_get(struct gfs2_sbd *sdp, u64 number, 
		mapping->writeback_index = 0;

	}



	write_lock(gl_lock_addr(hash));

	spin_lock_bucket(hash);

	tmp = search_bucket(hash, sdp, &name);

	if (tmp) {

		write_unlock(gl_lock_addr(hash));

		glock_free(gl);

		spin_unlock_bucket(hash);

		kmem_cache_free(cachep, gl);

		gl = tmp;

	} else {

		hlist_add_head(&gl->gl_list, &gl_hash_table[hash].hb_list);

		write_unlock(gl_lock_addr(hash));

		hlist_bl_add_head_rcu(&gl->gl_list, &gl_hash_table[hash]);

		spin_unlock_bucket(hash);

	}



	*glp = gl;
@@ -1113,6 +1078,7 @@ void gfs2_glock_dq(struct gfs2_holder *gh) 
		    !test_bit(GLF_DEMOTE, &gl->gl_flags))

			fast_path = 1;

	}

	__gfs2_glock_schedule_for_reclaim(gl);

	trace_gfs2_glock_queue(gh, 0);

	spin_unlock(&gl->gl_spin);

	if (likely(fast_path))
@@ -1440,42 +1406,30 @@ static struct shrinker glock_shrinker = { 
 * @sdp: the filesystem

 * @bucket: the bucket

 *

 * Returns: 1 if the bucket has entries

 */



static int examine_bucket(glock_examiner examiner, struct gfs2_sbd *sdp,

static void examine_bucket(glock_examiner examiner, const struct gfs2_sbd *sdp,

			  unsigned int hash)

{

	struct gfs2_glock *gl, *prev = NULL;

	int has_entries = 0;

	struct hlist_head *head = &gl_hash_table[hash].hb_list;

	struct gfs2_glock *gl;

	struct hlist_bl_head *head = &gl_hash_table[hash];

	struct hlist_bl_node *pos;



	read_lock(gl_lock_addr(hash));

	/* Can't use hlist_for_each_entry - don't want prefetch here */

	if (hlist_empty(head))

		goto out;

	gl = list_entry(head->first, struct gfs2_glock, gl_list);

	while(1) {

		if (!sdp || gl->gl_sbd == sdp) {

			gfs2_glock_hold(gl);

			read_unlock(gl_lock_addr(hash));

			if (prev)

				gfs2_glock_put(prev);

			prev = gl;

	rcu_read_lock();

	hlist_bl_for_each_entry_rcu(gl, pos, head, gl_list) {

		if ((gl->gl_sbd == sdp) && atomic_read(&gl->gl_ref))

			examiner(gl);

			has_entries = 1;

			read_lock(gl_lock_addr(hash));

	}

		if (gl->gl_list.next == NULL)

			break;

		gl = list_entry(gl->gl_list.next, struct gfs2_glock, gl_list);

	}

out:

	read_unlock(gl_lock_addr(hash));

	if (prev)

		gfs2_glock_put(prev);

	rcu_read_unlock();

	cond_resched();

	return has_entries;

}



static void glock_hash_walk(glock_examiner examiner, const struct gfs2_sbd *sdp)

{

	unsigned x;



	for (x = 0; x < GFS2_GL_HASH_SIZE; x++)

		examine_bucket(examiner, sdp, x);

}
@@ -1529,10 +1483,21 @@ static void clear_glock(struct gfs2_glock *gl) 


void gfs2_glock_thaw(struct gfs2_sbd *sdp)

{

	unsigned x;

	glock_hash_walk(thaw_glock, sdp);

}



	for (x = 0; x < GFS2_GL_HASH_SIZE; x++)

		examine_bucket(thaw_glock, sdp, x);

static int dump_glock(struct seq_file *seq, struct gfs2_glock *gl)

{

	int ret;

	spin_lock(&gl->gl_spin);

	ret = __dump_glock(seq, gl);

	spin_unlock(&gl->gl_spin);

	return ret;

}



static void dump_glock_func(struct gfs2_glock *gl)

{

	dump_glock(NULL, gl);

}



/**
@@ -1545,13 +1510,10 @@ void gfs2_glock_thaw(struct gfs2_sbd *sdp) 


void gfs2_gl_hash_clear(struct gfs2_sbd *sdp)

{

	unsigned int x;



	for (x = 0; x < GFS2_GL_HASH_SIZE; x++)

		examine_bucket(clear_glock, sdp, x);

	glock_hash_walk(clear_glock, sdp);

	flush_workqueue(glock_workqueue);

	wait_event(sdp->sd_glock_wait, atomic_read(&sdp->sd_glock_disposal) == 0);

	gfs2_dump_lockstate(sdp);

	glock_hash_walk(dump_glock_func, sdp);

}



void gfs2_glock_finish_truncate(struct gfs2_inode *ip)
@@ -1717,66 +1679,15 @@ out: 
	return error;

}



static int dump_glock(struct seq_file *seq, struct gfs2_glock *gl)

{

	int ret;

	spin_lock(&gl->gl_spin);

	ret = __dump_glock(seq, gl);

	spin_unlock(&gl->gl_spin);

	return ret;

}



/**

 * gfs2_dump_lockstate - print out the current lockstate

 * @sdp: the filesystem

 * @ub: the buffer to copy the information into

 *

 * If @ub is NULL, dump the lockstate to the console.

 *

 */



static int gfs2_dump_lockstate(struct gfs2_sbd *sdp)

{

	struct gfs2_glock *gl;

	struct hlist_node *h;

	unsigned int x;

	int error = 0;



	for (x = 0; x < GFS2_GL_HASH_SIZE; x++) {



		read_lock(gl_lock_addr(x));



		hlist_for_each_entry(gl, h, &gl_hash_table[x].hb_list, gl_list) {

			if (gl->gl_sbd != sdp)

				continue;



			error = dump_glock(NULL, gl);

			if (error)

				break;

		}



		read_unlock(gl_lock_addr(x));



		if (error)

			break;

	}





	return error;

}





int __init gfs2_glock_init(void)

{

	unsigned i;

	for(i = 0; i < GFS2_GL_HASH_SIZE; i++) {

		INIT_HLIST_HEAD(&gl_hash_table[i].hb_list);

	}

#ifdef GL_HASH_LOCK_SZ

	for(i = 0; i < GL_HASH_LOCK_SZ; i++) {

		rwlock_init(&gl_hash_locks[i]);

		INIT_HLIST_BL_HEAD(&gl_hash_table[i]);

	}

#endif



	glock_workqueue = alloc_workqueue("glock_workqueue", WQ_MEM_RECLAIM |

					  WQ_HIGHPRI | WQ_FREEZEABLE, 0);
@@ -1802,48 +1713,41 @@ void gfs2_glock_exit(void) 
	destroy_workqueue(gfs2_delete_workqueue);

}



static inline struct gfs2_glock *glock_hash_chain(unsigned hash)

{

	return hlist_bl_entry(hlist_bl_first_rcu(&gl_hash_table[hash]),

			      struct gfs2_glock, gl_list);

}



static inline struct gfs2_glock *glock_hash_next(struct gfs2_glock *gl)

{

	return hlist_bl_entry(rcu_dereference_raw(gl->gl_list.next),

			      struct gfs2_glock, gl_list);

}



static int gfs2_glock_iter_next(struct gfs2_glock_iter *gi)

{

	struct gfs2_glock *gl;



restart:

	read_lock(gl_lock_addr(gi->hash));

	do {

		gl = gi->gl;

		if (gl) {

		gi->gl = hlist_entry(gl->gl_list.next,

				     struct gfs2_glock, gl_list);

			gi->gl = glock_hash_next(gl);

		} else {

		gi->gl = hlist_entry(gl_hash_table[gi->hash].hb_list.first,

				     struct gfs2_glock, gl_list);

			gi->gl = glock_hash_chain(gi->hash);

		}

	if (gi->gl)

		gfs2_glock_hold(gi->gl);

	read_unlock(gl_lock_addr(gi->hash));

	if (gl)

		gfs2_glock_put(gl);

		while (gi->gl == NULL) {

			gi->hash++;

		if (gi->hash >= GFS2_GL_HASH_SIZE)

			if (gi->hash >= GFS2_GL_HASH_SIZE) {

				rcu_read_unlock();

				return 1;

		read_lock(gl_lock_addr(gi->hash));

		gi->gl = hlist_entry(gl_hash_table[gi->hash].hb_list.first,

				     struct gfs2_glock, gl_list);

		if (gi->gl)

			gfs2_glock_hold(gi->gl);

		read_unlock(gl_lock_addr(gi->hash));

			}



	if (gi->sdp != gi->gl->gl_sbd)

		goto restart;



	return 0;

			gi->gl = glock_hash_chain(gi->hash);

		}

	/* Skip entries for other sb and dead entries */

	} while (gi->sdp != gi->gl->gl_sbd || atomic_read(&gi->gl->gl_ref) == 0);



static void gfs2_glock_iter_free(struct gfs2_glock_iter *gi)

{

	if (gi->gl)

		gfs2_glock_put(gi->gl);

	gi->gl = NULL;

	return 0;

}



static void *gfs2_glock_seq_start(struct seq_file *seq, loff_t *pos)
@@ -1852,12 +1756,11 @@ static void *gfs2_glock_seq_start(struct seq_file *seq, loff_t *pos) 
	loff_t n = *pos;



	gi->hash = 0;

	rcu_read_lock();



	do {

		if (gfs2_glock_iter_next(gi)) {

			gfs2_glock_iter_free(gi);

		if (gfs2_glock_iter_next(gi))

			return NULL;

		}

	} while (n--);



	return gi->gl;
@@ -1870,10 +1773,8 @@ static void *gfs2_glock_seq_next(struct seq_file *seq, void *iter_ptr, 


	(*pos)++;



	if (gfs2_glock_iter_next(gi)) {

		gfs2_glock_iter_free(gi);

	if (gfs2_glock_iter_next(gi))

		return NULL;

	}



	return gi->gl;

}
@@ -1881,7 +1782,10 @@ static void *gfs2_glock_seq_next(struct seq_file *seq, void *iter_ptr, 
static void gfs2_glock_seq_stop(struct seq_file *seq, void *iter_ptr)

{

	struct gfs2_glock_iter *gi = seq->private;

	gfs2_glock_iter_free(gi);



	if (gi->gl)

		rcu_read_unlock();

	gi->gl = NULL;

}



static int gfs2_glock_seq_show(struct seq_file *seq, void *iter_ptr)

fs/gfs2/glock.h

+18 −21
Original line number Diff line number Diff line
@@ -118,7 +118,7 @@ struct lm_lockops { 
	int (*lm_mount) (struct gfs2_sbd *sdp, const char *fsname);

 	void (*lm_unmount) (struct gfs2_sbd *sdp);

	void (*lm_withdraw) (struct gfs2_sbd *sdp);

	void (*lm_put_lock) (struct kmem_cache *cachep, struct gfs2_glock *gl);

	void (*lm_put_lock) (struct gfs2_glock *gl);

	int (*lm_lock) (struct gfs2_glock *gl, unsigned int req_state,

			unsigned int flags);

	void (*lm_cancel) (struct gfs2_glock *gl);
@@ -174,7 +174,7 @@ int gfs2_glock_get(struct gfs2_sbd *sdp, 
		   int create, struct gfs2_glock **glp);

void gfs2_glock_hold(struct gfs2_glock *gl);

void gfs2_glock_put_nolock(struct gfs2_glock *gl);

int gfs2_glock_put(struct gfs2_glock *gl);

void gfs2_glock_put(struct gfs2_glock *gl);

void gfs2_holder_init(struct gfs2_glock *gl, unsigned int state, unsigned flags,

		      struct gfs2_holder *gh);

void gfs2_holder_reinit(unsigned int state, unsigned flags,
@@ -223,25 +223,22 @@ static inline int gfs2_glock_nq_init(struct gfs2_glock *gl, 
	return error;

}



/*  Lock Value Block functions  */



int gfs2_lvb_hold(struct gfs2_glock *gl);

void gfs2_lvb_unhold(struct gfs2_glock *gl);



void gfs2_glock_cb(struct gfs2_glock *gl, unsigned int state);

void gfs2_glock_complete(struct gfs2_glock *gl, int ret);

void gfs2_reclaim_glock(struct gfs2_sbd *sdp);

void gfs2_gl_hash_clear(struct gfs2_sbd *sdp);

void gfs2_glock_finish_truncate(struct gfs2_inode *ip);

void gfs2_glock_thaw(struct gfs2_sbd *sdp);



int __init gfs2_glock_init(void);

void gfs2_glock_exit(void);



int gfs2_create_debugfs_file(struct gfs2_sbd *sdp);

void gfs2_delete_debugfs_file(struct gfs2_sbd *sdp);

int gfs2_register_debugfs(void);

void gfs2_unregister_debugfs(void);

extern void gfs2_glock_cb(struct gfs2_glock *gl, unsigned int state);

extern void gfs2_glock_complete(struct gfs2_glock *gl, int ret);

extern void gfs2_reclaim_glock(struct gfs2_sbd *sdp);

extern void gfs2_gl_hash_clear(struct gfs2_sbd *sdp);

extern void gfs2_glock_finish_truncate(struct gfs2_inode *ip);

extern void gfs2_glock_thaw(struct gfs2_sbd *sdp);

extern void gfs2_glock_schedule_for_reclaim(struct gfs2_glock *gl);

extern void gfs2_glock_free(struct rcu_head *rcu);



extern int __init gfs2_glock_init(void);

extern void gfs2_glock_exit(void);



extern int gfs2_create_debugfs_file(struct gfs2_sbd *sdp);

extern void gfs2_delete_debugfs_file(struct gfs2_sbd *sdp);

extern int gfs2_register_debugfs(void);

extern void gfs2_unregister_debugfs(void);



extern const struct lm_lockops gfs2_dlm_ops;

fs/gfs2/glops.c

+9 −14
Original line number Diff line number Diff line
@@ -206,8 +206,17 @@ static void inode_go_inval(struct gfs2_glock *gl, int flags) 
static int inode_go_demote_ok(const struct gfs2_glock *gl)

{

	struct gfs2_sbd *sdp = gl->gl_sbd;

	struct gfs2_holder *gh;



	if (sdp->sd_jindex == gl->gl_object || sdp->sd_rindex == gl->gl_object)

		return 0;



	if (!list_empty(&gl->gl_holders)) {

		gh = list_entry(gl->gl_holders.next, struct gfs2_holder, gh_list);

		if (gh->gh_list.next != &gl->gl_holders)

			return 0;

	}



	return 1;

}
@@ -271,19 +280,6 @@ static int inode_go_dump(struct seq_file *seq, const struct gfs2_glock *gl) 
	return 0;

}



/**

 * rgrp_go_demote_ok - Check to see if it's ok to unlock a RG's glock

 * @gl: the glock

 *

 * Returns: 1 if it's ok

 */



static int rgrp_go_demote_ok(const struct gfs2_glock *gl)

{

	const struct address_space *mapping = (const struct address_space *)(gl + 1);

	return !mapping->nrpages;

}



/**

 * rgrp_go_lock - operation done after an rgrp lock is locked by

 *    a first holder on this node.
@@ -410,7 +406,6 @@ const struct gfs2_glock_operations gfs2_inode_glops = { 
const struct gfs2_glock_operations gfs2_rgrp_glops = {

	.go_xmote_th = rgrp_go_sync,

	.go_inval = rgrp_go_inval,

	.go_demote_ok = rgrp_go_demote_ok,

	.go_lock = rgrp_go_lock,

	.go_unlock = rgrp_go_unlock,

	.go_dump = gfs2_rgrp_dump,

fs/gfs2/incore.h

+4 −1
Original line number Diff line number Diff line
@@ -15,6 +15,8 @@ 
#include <linux/workqueue.h>

#include <linux/dlm.h>

#include <linux/buffer_head.h>

#include <linux/rcupdate.h>

#include <linux/rculist_bl.h>



#define DIO_WAIT	0x00000010

#define DIO_METADATA	0x00000020
@@ -201,7 +203,7 @@ enum { 
};



struct gfs2_glock {

	struct hlist_node gl_list;

	struct hlist_bl_node gl_list;

	unsigned long gl_flags;		/* GLF_... */

	struct lm_lockname gl_name;

	atomic_t gl_ref;
@@ -234,6 +236,7 @@ struct gfs2_glock { 
	atomic_t gl_ail_count;

	struct delayed_work gl_work;

	struct work_struct gl_delete;

	struct rcu_head gl_rcu;

};



#define GFS2_MIN_LVB_SIZE 32	/* Min size of LVB that gfs2 supports */

fs/gfs2/lock_dlm.c

+3 −11
Original line number Diff line number Diff line
@@ -22,7 +22,6 @@ static void gdlm_ast(void *arg) 
{

	struct gfs2_glock *gl = arg;

	unsigned ret = gl->gl_state;

	struct gfs2_sbd *sdp = gl->gl_sbd;



	BUG_ON(gl->gl_lksb.sb_flags & DLM_SBF_DEMOTED);
@@ -31,12 +30,7 @@ static void gdlm_ast(void *arg) 


	switch (gl->gl_lksb.sb_status) {

	case -DLM_EUNLOCK: /* Unlocked, so glock can be freed */

		if (gl->gl_ops->go_flags & GLOF_ASPACE)

			kmem_cache_free(gfs2_glock_aspace_cachep, gl);

		else

			kmem_cache_free(gfs2_glock_cachep, gl);

		if (atomic_dec_and_test(&sdp->sd_glock_disposal))

			wake_up(&sdp->sd_glock_wait);

		call_rcu(&gl->gl_rcu, gfs2_glock_free);

		return;

	case -DLM_ECANCEL: /* Cancel while getting lock */

		ret |= LM_OUT_CANCELED;
@@ -164,16 +158,14 @@ static int gdlm_lock(struct gfs2_glock *gl, unsigned int req_state, 
			GDLM_STRNAME_BYTES - 1, 0, gdlm_ast, gl, gdlm_bast);

}



static void gdlm_put_lock(struct kmem_cache *cachep, struct gfs2_glock *gl)

static void gdlm_put_lock(struct gfs2_glock *gl)

{

	struct gfs2_sbd *sdp = gl->gl_sbd;

	struct lm_lockstruct *ls = &sdp->sd_lockstruct;

	int error;



	if (gl->gl_lksb.sb_lkid == 0) {

		kmem_cache_free(cachep, gl);

		if (atomic_dec_and_test(&sdp->sd_glock_disposal))

			wake_up(&sdp->sd_glock_wait);

		call_rcu(&gl->gl_rcu, gfs2_glock_free);

		return;

	}

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