#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"
#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 */
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);
#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
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);
+ }
+
+ static void gfs2_glock_dealloc(struct rcu_head *rcu)
+ {
+ struct gfs2_glock *gl = container_of(rcu, struct gfs2_glock, gl_rcu);
+
+ if (gl->gl_ops->go_flags & GLOF_ASPACE)
+ kmem_cache_free(gfs2_glock_aspace_cachep, gl);
+ else
+ kmem_cache_free(gfs2_glock_cachep, gl);
+ }
+
+ void gfs2_glock_free(struct gfs2_glock *gl)
{
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);
+ call_rcu(&gl->gl_rcu, gfs2_glock_dealloc);
+ if (atomic_dec_and_test(&sdp->sd_glock_disposal))
+ wake_up(&sdp->sd_glock_wait);
}
/**
{
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)));
- spin_lock(&lru_lock);
- if (list_empty(&gl->gl_lru) && may_reclaim) {
+ if (demote_ok(gl)) {
+ spin_lock(&lru_lock);
+
+ 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);
- atomic_inc(&lru_count);
+ spin_unlock(&lru_lock);
}
- 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);
}
/**
{
if (atomic_dec_and_test(&gl->gl_ref))
GLOCK_BUG_ON(gl, 1);
- gfs2_glock_schedule_for_reclaim(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;
}
/**
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);
-
- return gl;
+ if (atomic_inc_not_zero(&gl->gl_ref))
+ return gl;
}
return NULL;
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)
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;
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);
+ atomic_dec(&sdp->sd_glock_disposal);
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;
insert_pt = &gh2->gh_list;
}
set_bit(GLF_QUEUED, &gl->gl_flags);
+ trace_gfs2_glock_queue(gh, 1);
if (likely(insert_pt == NULL)) {
list_add_tail(&gh->gh_list, &gl->gl_holders);
if (unlikely(gh->gh_flags & LM_FLAG_PRIORITY))
goto do_cancel;
return;
}
- trace_gfs2_glock_queue(gh, 1);
list_add_tail(&gh->gh_list, insert_pt);
do_cancel:
gh = list_entry(gl->gl_holders.next, struct gfs2_holder, gh_list);
!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))
void gfs2_glock_dq_m(unsigned int num_gh, struct gfs2_holder *ghs)
{
- unsigned int x;
-
- for (x = 0; x < num_gh; x++)
- gfs2_glock_dq(&ghs[x]);
+ while (num_gh--)
+ gfs2_glock_dq(&ghs[num_gh]);
}
/**
void gfs2_glock_dq_uninit_m(unsigned int num_gh, struct gfs2_holder *ghs)
{
- unsigned int x;
-
- for (x = 0; x < num_gh; x++)
- gfs2_glock_dq_uninit(&ghs[x]);
+ while (num_gh--)
+ gfs2_glock_dq_uninit(&ghs[num_gh]);
}
void gfs2_glock_cb(struct gfs2_glock *gl, unsigned int state)
* @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);
}
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);
}
/**
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)
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);
+ WQ_HIGHPRI | WQ_FREEZABLE, 0);
if (IS_ERR(glock_workqueue))
return PTR_ERR(glock_workqueue);
gfs2_delete_workqueue = alloc_workqueue("delete_workqueue",
- WQ_MEM_RECLAIM | WQ_FREEZEABLE,
+ WQ_MEM_RECLAIM | WQ_FREEZABLE,
0);
if (IS_ERR(gfs2_delete_workqueue)) {
destroy_workqueue(glock_workqueue);
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(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));
- gl = gi->gl;
- if (gl) {
- gi->gl = hlist_entry(gl->gl_list.next,
- struct gfs2_glock, gl_list);
- } else {
- 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 (gl)
- gfs2_glock_put(gl);
- while (gi->gl == NULL) {
- gi->hash++;
- if (gi->hash >= GFS2_GL_HASH_SIZE)
- 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;
+ do {
+ gl = gi->gl;
+ if (gl) {
+ gi->gl = glock_hash_next(gl);
+ } else {
+ gi->gl = glock_hash_chain(gi->hash);
+ }
+ while (gi->gl == NULL) {
+ gi->hash++;
+ if (gi->hash >= GFS2_GL_HASH_SIZE) {
+ rcu_read_unlock();
+ return 1;
+ }
+ 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);
return 0;
}
- static void gfs2_glock_iter_free(struct gfs2_glock_iter *gi)
- {
- if (gi->gl)
- gfs2_glock_put(gi->gl);
- gi->gl = NULL;
- }
-
static void *gfs2_glock_seq_start(struct seq_file *seq, loff_t *pos)
{
struct gfs2_glock_iter *gi = seq->private;
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;
(*pos)++;
- if (gfs2_glock_iter_next(gi)) {
- gfs2_glock_iter_free(gi);
+ if (gfs2_glock_iter_next(gi))
return NULL;
- }
return gi->gl;
}
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)
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