--- /dev/null
+--- /dev/null 2011-12-14 22:16:16.000000000 +0800
++++ linux-2.6.32-131.6.1-pdo/include/linux/htree_lock.h 2011-12-02 17:09:34.000000000 +0800
+@@ -0,0 +1,187 @@
++/*
++ * include/linux/htree_lock.h
++ *
++ * Copyright (c) 2011 Whamcloud, Inc.
++ *
++ * Author: Liang Zhen <liang@whamcloud.com>
++ */
++
++/*
++ * htree lock
++ *
++ * htree_lock is an advanced lock, it can support five lock modes (concept is
++ * taken from DLM) and it's a sleeping lock.
++ *
++ * most common use case is:
++ * - create a htree_lock_head for data
++ * - each thread (contender) creates it's own htree_lock
++ * - contender needs to call htree_lock(lock_node, mode) to protect data and
++ * call htree_unlock to release lock
++ *
++ * Also, there is advanced use-case which is more complex, user can have
++ * PW/PR lock on particular key, it's mostly used while user holding shared
++ * lock on the htree (CW, CR)
++ *
++ * htree_lock(lock_node, HTREE_LOCK_CR); lock the htree with CR
++ * htree_node_lock(lock_node, HTREE_LOCK_PR, key...); lock @key with PR
++ * ...
++ * htree_node_unlock(lock_node);; unlock the key
++ *
++ * Another tip is, we can have N-levels of this kind of keys, all we need to
++ * do is specifying N-levels while creating htree_lock_head, then we can
++ * lock/unlock a specific level by:
++ * htree_node_lock(lock_node, mode1, key1, level1...);
++ * do something;
++ * htree_node_lock(lock_node, mode1, key2, level2...);
++ * do something;
++ * htree_node_unlock(lock_node, level2);
++ * htree_node_unlock(lock_node, level1);
++ *
++ * NB: for multi-level, should be careful about locking order to avoid deadlock
++ */
++
++#ifndef _LINUX_HTREE_LOCK_H
++#define _LINUX_HTREE_LOCK_H
++
++#include <linux/list.h>
++#include <linux/spinlock.h>
++#include <linux/sched.h>
++
++/*
++ * Lock Modes
++ * more details can be found here:
++ * http://en.wikipedia.org/wiki/Distributed_lock_manager
++ */
++typedef enum {
++ HTREE_LOCK_EX = 0, /* exclusive lock: incompatible with all others */
++ HTREE_LOCK_PW, /* protected write: allows only CR users */
++ HTREE_LOCK_PR, /* protected read: allow PR, CR users */
++ HTREE_LOCK_CW, /* concurrent write: allow CR, CW users */
++ HTREE_LOCK_CR, /* concurrent read: allow all but EX users */
++ HTREE_LOCK_MAX, /* number of lock modes */
++} htree_lock_mode_t;
++
++#define HTREE_LOCK_NL HTREE_LOCK_MAX
++#define HTREE_LOCK_INVAL 0xdead10c
++
++enum {
++ HTREE_HBITS_MIN = 2,
++ HTREE_HBITS_DEF = 14,
++ HTREE_HBITS_MAX = 32,
++};
++
++enum {
++ HTREE_EVENT_DISABLE = (0),
++ HTREE_EVENT_RD = (1 << HTREE_LOCK_PR),
++ HTREE_EVENT_WR = (1 << HTREE_LOCK_PW),
++ HTREE_EVENT_RDWR = (HTREE_EVENT_RD | HTREE_EVENT_WR),
++};
++
++struct htree_lock;
++
++typedef void (*htree_event_cb_t)(void *target, void *event);
++
++struct htree_lock_child {
++ struct list_head lc_list; /* granted list */
++ htree_event_cb_t lc_callback; /* event callback */
++ unsigned lc_events; /* event types */
++};
++
++struct htree_lock_head {
++ unsigned long lh_lock; /* bits lock */
++ /* blocked lock list (htree_lock) */
++ struct list_head lh_blocked_list;
++ /* # key levels */
++ u16 lh_depth;
++ /* hash bits for key and limit number of locks */
++ u16 lh_hbits;
++ /* counters for blocked locks */
++ u16 lh_nblocked[HTREE_LOCK_MAX];
++ /* counters for granted locks */
++ u16 lh_ngranted[HTREE_LOCK_MAX];
++ /* private data */
++ void *lh_private;
++ /* array of children locks */
++ struct htree_lock_child lh_children[0];
++};
++
++/* htree_lock_node_t is child-lock for a specific key (ln_value) */
++struct htree_lock_node {
++ htree_lock_mode_t ln_mode;
++ /* major hash key */
++ u16 ln_major_key;
++ /* minor hash key */
++ u16 ln_minor_key;
++ struct list_head ln_major_list;
++ struct list_head ln_minor_list;
++ /* alive list, all locks (granted, blocked, listening) are on it */
++ struct list_head ln_alive_list;
++ /* blocked list */
++ struct list_head ln_blocked_list;
++ /* granted list */
++ struct list_head ln_granted_list;
++ void *ln_ev_target;
++};
++
++struct htree_lock {
++ struct task_struct *lk_task;
++ struct htree_lock_head *lk_head;
++ void *lk_private;
++ unsigned lk_depth;
++ htree_lock_mode_t lk_mode;
++ struct list_head lk_blocked_list;
++ struct htree_lock_node lk_nodes[0];
++};
++
++/* create a lock head, which stands for a resource */
++struct htree_lock_head *htree_lock_head_alloc(unsigned depth,
++ unsigned hbits, unsigned priv);
++/* free a lock head */
++void htree_lock_head_free(struct htree_lock_head *lhead);
++/* register event callback for child lock at level @depth */
++void htree_lock_event_attach(struct htree_lock_head *lhead, unsigned depth,
++ unsigned events, htree_event_cb_t callback);
++/* create a lock handle, which stands for a thread */
++struct htree_lock *htree_lock_alloc(unsigned depth, unsigned pbytes);
++/* free a lock handle */
++void htree_lock_free(struct htree_lock *lck);
++/* lock htree, when @wait is true, 0 is returned if the lock can't
++ * be granted immediately */
++int htree_lock_try(struct htree_lock *lck, struct htree_lock_head *lhead,
++ htree_lock_mode_t mode, int wait);
++/* unlock htree */
++void htree_unlock(struct htree_lock *lck);
++/* unlock and relock htree with @new_mode */
++int htree_change_lock_try(struct htree_lock *lck,
++ htree_lock_mode_t new_mode, int wait);
++void htree_change_mode(struct htree_lock *lck, htree_lock_mode_t mode);
++/* require child lock (key) of htree at level @dep, @event will be sent to all
++ * listeners on this @key while lock being granted */
++int htree_node_lock_try(struct htree_lock *lck, htree_lock_mode_t mode,
++ u32 key, unsigned dep, int wait, void *event);
++/* release child lock at level @dep, this lock will listen on it's key
++ * if @event isn't NULL, event_cb will be called against @lck while granting
++ * any other lock at level @dep with the same key */
++void htree_node_unlock(struct htree_lock *lck, unsigned dep, void *event);
++/* stop listening on child lock at level @dep */
++void htree_node_stop_listen(struct htree_lock *lck, unsigned dep);
++/* for debug */
++void htree_lock_stat_print(int depth);
++void htree_lock_stat_reset(void);
++
++#define htree_lock(lck, lh, mode) htree_lock_try(lck, lh, mode, 1)
++#define htree_change_lock(lck, mode) htree_change_lock_try(lck, mode, 1)
++
++#define htree_lock_mode(lck) ((lck)->lk_mode)
++
++#define htree_node_lock(lck, mode, key, dep) \
++ htree_node_lock_try(lck, mode, key, dep, 1, NULL)
++/* this is only safe in thread context of lock owner */
++#define htree_node_is_granted(lck, dep) \
++ ((lck)->lk_nodes[dep].ln_mode != HTREE_LOCK_INVAL && \
++ (lck)->lk_nodes[dep].ln_mode != HTREE_LOCK_NL)
++/* this is only safe in thread context of lock owner */
++#define htree_node_is_listening(lck, dep) \
++ ((lck)->lk_nodes[dep].ln_mode == HTREE_LOCK_NL)
++
++#endif
+--- /dev/null 2011-12-14 22:16:16.000000000 +0800
++++ linux-2.6.32-131.6.1-pdo/fs/ext4/htree_lock.c 2011-12-14 22:56:28.000000000 +0800
+@@ -0,0 +1,880 @@
++/*
++ * fs/ext4/htree_lock.c
++ *
++ * Copyright (c) 2011 Whamcloud, Inc.
++ *
++ * Author: Liang Zhen <liang@whamcloud.com>
++ */
++#include <linux/jbd2.h>
++#include <linux/hash.h>
++#include <linux/module.h>
++#include <linux/htree_lock.h>
++
++enum {
++ HTREE_LOCK_BIT_EX = (1 << HTREE_LOCK_EX),
++ HTREE_LOCK_BIT_PW = (1 << HTREE_LOCK_PW),
++ HTREE_LOCK_BIT_PR = (1 << HTREE_LOCK_PR),
++ HTREE_LOCK_BIT_CW = (1 << HTREE_LOCK_CW),
++ HTREE_LOCK_BIT_CR = (1 << HTREE_LOCK_CR),
++};
++
++enum {
++ HTREE_LOCK_COMPAT_EX = 0,
++ HTREE_LOCK_COMPAT_PW = HTREE_LOCK_COMPAT_EX | HTREE_LOCK_BIT_CR,
++ HTREE_LOCK_COMPAT_PR = HTREE_LOCK_COMPAT_PW | HTREE_LOCK_BIT_PR,
++ HTREE_LOCK_COMPAT_CW = HTREE_LOCK_COMPAT_PW | HTREE_LOCK_BIT_CW,
++ HTREE_LOCK_COMPAT_CR = HTREE_LOCK_COMPAT_CW | HTREE_LOCK_BIT_PR |
++ HTREE_LOCK_BIT_PW,
++};
++
++static int htree_lock_compat[] = {
++ [HTREE_LOCK_EX] HTREE_LOCK_COMPAT_EX,
++ [HTREE_LOCK_PW] HTREE_LOCK_COMPAT_PW,
++ [HTREE_LOCK_PR] HTREE_LOCK_COMPAT_PR,
++ [HTREE_LOCK_CW] HTREE_LOCK_COMPAT_CW,
++ [HTREE_LOCK_CR] HTREE_LOCK_COMPAT_CR,
++};
++
++/* max allowed htree-lock depth.
++ * We only need depth=3 for ext4 although user can have higher value. */
++#define HTREE_LOCK_DEP_MAX 16
++
++#ifdef HTREE_LOCK_DEBUG
++
++static char *hl_name[] = {
++ [HTREE_LOCK_EX] "EX",
++ [HTREE_LOCK_PW] "PW",
++ [HTREE_LOCK_PR] "PR",
++ [HTREE_LOCK_CW] "CW",
++ [HTREE_LOCK_CR] "CR",
++};
++
++/* lock stats */
++struct htree_lock_node_stats {
++ unsigned long long blocked[HTREE_LOCK_MAX];
++ unsigned long long granted[HTREE_LOCK_MAX];
++ unsigned long long retried[HTREE_LOCK_MAX];
++ unsigned long long events;
++};
++
++struct htree_lock_stats {
++ struct htree_lock_node_stats nodes[HTREE_LOCK_DEP_MAX];
++ unsigned long long granted[HTREE_LOCK_MAX];
++ unsigned long long blocked[HTREE_LOCK_MAX];
++};
++
++static struct htree_lock_stats hl_stats;
++
++void htree_lock_stat_reset(void)
++{
++ memset(&hl_stats, 0, sizeof(hl_stats));
++}
++
++void htree_lock_stat_print(int depth)
++{
++ int i;
++ int j;
++
++ printk(KERN_DEBUG "HTREE LOCK STATS:\n");
++ for (i = 0; i < HTREE_LOCK_MAX; i++) {
++ printk(KERN_DEBUG "[%s]: G [%10llu], B [%10llu]\n",
++ hl_name[i], hl_stats.granted[i], hl_stats.blocked[i]);
++ }
++ for (i = 0; i < depth; i++) {
++ printk(KERN_DEBUG "HTREE CHILD [%d] STATS:\n", i);
++ for (j = 0; j < HTREE_LOCK_MAX; j++) {
++ printk(KERN_DEBUG
++ "[%s]: G [%10llu], B [%10llu], R [%10llu]\n",
++ hl_name[j], hl_stats.nodes[i].granted[j],
++ hl_stats.nodes[i].blocked[j],
++ hl_stats.nodes[i].retried[j]);
++ }
++ }
++}
++
++#define lk_grant_inc(m) do { hl_stats.granted[m]++; } while (0)
++#define lk_block_inc(m) do { hl_stats.blocked[m]++; } while (0)
++#define ln_grant_inc(d, m) do { hl_stats.nodes[d].granted[m]++; } while (0)
++#define ln_block_inc(d, m) do { hl_stats.nodes[d].blocked[m]++; } while (0)
++#define ln_retry_inc(d, m) do { hl_stats.nodes[d].retried[m]++; } while (0)
++#define ln_event_inc(d) do { hl_stats.nodes[d].events++; } while (0)
++
++#else /* !DEBUG */
++
++void htree_lock_stat_reset(void) {}
++void htree_lock_stat_print(int depth) {}
++
++#define lk_grant_inc(m) do {} while (0)
++#define lk_block_inc(m) do {} while (0)
++#define ln_grant_inc(d, m) do {} while (0)
++#define ln_block_inc(d, m) do {} while (0)
++#define ln_retry_inc(d, m) do {} while (0)
++#define ln_event_inc(d) do {} while (0)
++
++#endif /* DEBUG */
++
++EXPORT_SYMBOL(htree_lock_stat_reset);
++EXPORT_SYMBOL(htree_lock_stat_print);
++
++#define HTREE_DEP_ROOT (-1)
++
++#define htree_spin_lock(lhead, dep) \
++ bit_spin_lock((dep) + 1, &(lhead)->lh_lock)
++#define htree_spin_unlock(lhead, dep) \
++ bit_spin_unlock((dep) + 1, &(lhead)->lh_lock)
++
++#define htree_key_event_ignore(child, ln) \
++ (!((child)->lc_events & (1 << (ln)->ln_mode)))
++
++static int
++htree_key_list_empty(struct htree_lock_node *ln)
++{
++ return list_empty(&ln->ln_major_list) && list_empty(&ln->ln_minor_list);
++}
++
++static void
++htree_key_list_del_init(struct htree_lock_node *ln)
++{
++ struct htree_lock_node *tmp = NULL;
++
++ if (!list_empty(&ln->ln_minor_list)) {
++ tmp = list_entry(ln->ln_minor_list.next,
++ struct htree_lock_node, ln_minor_list);
++ list_del_init(&ln->ln_minor_list);
++ }
++
++ if (list_empty(&ln->ln_major_list))
++ return;
++
++ if (tmp == NULL) { /* not on minor key list */
++ list_del_init(&ln->ln_major_list);
++ } else {
++ BUG_ON(!list_empty(&tmp->ln_major_list));
++ list_replace_init(&ln->ln_major_list, &tmp->ln_major_list);
++ }
++}
++
++static void
++htree_key_list_replace_init(struct htree_lock_node *old,
++ struct htree_lock_node *new)
++{
++ if (!list_empty(&old->ln_major_list))
++ list_replace_init(&old->ln_major_list, &new->ln_major_list);
++
++ if (!list_empty(&old->ln_minor_list))
++ list_replace_init(&old->ln_minor_list, &new->ln_minor_list);
++}
++
++static void
++htree_key_event_enqueue(struct htree_lock_child *child,
++ struct htree_lock_node *ln, int dep, void *event)
++{
++ struct htree_lock_node *tmp;
++
++ /* NB: ALWAYS called holding lhead::lh_lock(dep) */
++ BUG_ON(ln->ln_mode == HTREE_LOCK_NL);
++ if (event == NULL || htree_key_event_ignore(child, ln))
++ return;
++
++ /* shouldn't be a very long list */
++ list_for_each_entry(tmp, &ln->ln_alive_list, ln_alive_list) {
++ if (tmp->ln_mode == HTREE_LOCK_NL) {
++ ln_event_inc(dep);
++ if (child->lc_callback != NULL)
++ child->lc_callback(tmp->ln_ev_target, event);
++ }
++ }
++}
++
++static int
++htree_node_lock_enqueue(struct htree_lock *newlk, struct htree_lock *curlk,
++ unsigned dep, int wait, void *event)
++{
++ struct htree_lock_child *child = &newlk->lk_head->lh_children[dep];
++ struct htree_lock_node *newln = &newlk->lk_nodes[dep];
++ struct htree_lock_node *curln = &curlk->lk_nodes[dep];
++
++ /* NB: ALWAYS called holding lhead::lh_lock(dep) */
++ /* NB: we only expect PR/PW lock mode at here, only these two modes are
++ * allowed for htree_node_lock(asserted in htree_node_lock_internal),
++ * NL is only used for listener, user can't directly require NL mode */
++ if ((curln->ln_mode == HTREE_LOCK_NL) ||
++ (curln->ln_mode != HTREE_LOCK_PW &&
++ newln->ln_mode != HTREE_LOCK_PW)) {
++ /* no conflict, attach it on granted list of @curlk */
++ if (curln->ln_mode != HTREE_LOCK_NL) {
++ list_add(&newln->ln_granted_list,
++ &curln->ln_granted_list);
++ } else {
++ /* replace key owner */
++ htree_key_list_replace_init(curln, newln);
++ }
++
++ list_add(&newln->ln_alive_list, &curln->ln_alive_list);
++ htree_key_event_enqueue(child, newln, dep, event);
++ ln_grant_inc(dep, newln->ln_mode);
++ return 1; /* still hold lh_lock */
++ }
++
++ if (!wait) { /* can't grant and don't want to wait */
++ ln_retry_inc(dep, newln->ln_mode);
++ newln->ln_mode = HTREE_LOCK_INVAL;
++ return -1; /* don't wait and just return -1 */
++ }
++
++ newlk->lk_task = current;
++ set_current_state(TASK_UNINTERRUPTIBLE);
++ /* conflict, attach it on blocked list of curlk */
++ list_add_tail(&newln->ln_blocked_list, &curln->ln_blocked_list);
++ list_add(&newln->ln_alive_list, &curln->ln_alive_list);
++ ln_block_inc(dep, newln->ln_mode);
++
++ htree_spin_unlock(newlk->lk_head, dep);
++ /* wait to be given the lock */
++ if (newlk->lk_task != NULL)
++ schedule();
++ /* granted, no doubt, wake up will set me RUNNING */
++ if (event == NULL || htree_key_event_ignore(child, newln))
++ return 0; /* granted without lh_lock */
++
++ htree_spin_lock(newlk->lk_head, dep);
++ htree_key_event_enqueue(child, newln, dep, event);
++ return 1; /* still hold lh_lock */
++}
++
++/*
++ * get PR/PW access to particular tree-node according to @dep and @key,
++ * it will return -1 if @wait is false and can't immediately grant this lock.
++ * All listeners(HTREE_LOCK_NL) on @dep and with the same @key will get
++ * @event if it's not NULL.
++ * NB: ALWAYS called holding lhead::lh_lock
++ */
++static int
++htree_node_lock_internal(struct htree_lock_head *lhead, struct htree_lock *lck,
++ htree_lock_mode_t mode, u32 key, unsigned dep,
++ int wait, void *event)
++{
++ LIST_HEAD (list);
++ struct htree_lock *tmp;
++ struct htree_lock *tmp2;
++ u16 major;
++ u16 minor;
++ u8 reverse;
++ u8 ma_bits;
++ u8 mi_bits;
++
++ BUG_ON(mode != HTREE_LOCK_PW && mode != HTREE_LOCK_PR);
++ BUG_ON(htree_node_is_granted(lck, dep));
++
++ key = hash_long(key, lhead->lh_hbits);
++
++ mi_bits = lhead->lh_hbits >> 1;
++ ma_bits = lhead->lh_hbits - mi_bits;
++
++ lck->lk_nodes[dep].ln_major_key = major = key & ((1U << ma_bits) - 1);
++ lck->lk_nodes[dep].ln_minor_key = minor = key >> ma_bits;
++ lck->lk_nodes[dep].ln_mode = mode;
++
++ /*
++ * The major key list is an ordered list, so searches are started
++ * at the end of the list that is numerically closer to major_key,
++ * so at most half of the list will be walked (for well-distributed
++ * keys). The list traversal aborts early if the expected key
++ * location is passed.
++ */
++ reverse = (major >= (1 << (ma_bits - 1)));
++
++ if (reverse) {
++ list_for_each_entry_reverse(tmp,
++ &lhead->lh_children[dep].lc_list,
++ lk_nodes[dep].ln_major_list) {
++ if (tmp->lk_nodes[dep].ln_major_key == major) {
++ goto search_minor;
++
++ } else if (tmp->lk_nodes[dep].ln_major_key < major) {
++ /* attach _after_ @tmp */
++ list_add(&lck->lk_nodes[dep].ln_major_list,
++ &tmp->lk_nodes[dep].ln_major_list);
++ goto out_grant_major;
++ }
++ }
++
++ list_add(&lck->lk_nodes[dep].ln_major_list,
++ &lhead->lh_children[dep].lc_list);
++ goto out_grant_major;
++
++ } else {
++ list_for_each_entry(tmp, &lhead->lh_children[dep].lc_list,
++ lk_nodes[dep].ln_major_list) {
++ if (tmp->lk_nodes[dep].ln_major_key == major) {
++ goto search_minor;
++
++ } else if (tmp->lk_nodes[dep].ln_major_key > major) {
++ /* insert _before_ @tmp */
++ list_add_tail(&lck->lk_nodes[dep].ln_major_list,
++ &tmp->lk_nodes[dep].ln_major_list);
++ goto out_grant_major;
++ }
++ }
++
++ list_add_tail(&lck->lk_nodes[dep].ln_major_list,
++ &lhead->lh_children[dep].lc_list);
++ goto out_grant_major;
++ }
++
++ search_minor:
++ /*
++ * NB: minor_key list doesn't have a "head", @list is just a
++ * temporary stub for helping list searching, make sure it's removed
++ * after searching.
++ * minor_key list is an ordered list too.
++ */
++ list_add_tail(&list, &tmp->lk_nodes[dep].ln_minor_list);
++
++ reverse = (minor >= (1 << (mi_bits - 1)));
++
++ if (reverse) {
++ list_for_each_entry_reverse(tmp2, &list,
++ lk_nodes[dep].ln_minor_list) {
++ if (tmp2->lk_nodes[dep].ln_minor_key == minor) {
++ goto out_enqueue;
++
++ } else if (tmp2->lk_nodes[dep].ln_minor_key < minor) {
++ /* attach _after_ @tmp2 */
++ list_add(&lck->lk_nodes[dep].ln_minor_list,
++ &tmp2->lk_nodes[dep].ln_minor_list);
++ goto out_grant_minor;
++ }
++ }
++
++ list_add(&lck->lk_nodes[dep].ln_minor_list, &list);
++
++ } else {
++ list_for_each_entry(tmp2, &list,
++ lk_nodes[dep].ln_minor_list) {
++ if (tmp2->lk_nodes[dep].ln_minor_key == minor) {
++ goto out_enqueue;
++
++ } else if (tmp2->lk_nodes[dep].ln_minor_key > minor) {
++ /* insert _before_ @tmp2 */
++ list_add_tail(&lck->lk_nodes[dep].ln_minor_list,
++ &tmp2->lk_nodes[dep].ln_minor_list);
++ goto out_grant_minor;
++ }
++ }
++
++ list_add_tail(&lck->lk_nodes[dep].ln_minor_list, &list);
++ }
++
++ out_grant_minor:
++ if (list.next == &lck->lk_nodes[dep].ln_minor_list) {
++ /* new lock @lck is the first one on minor_key list, which
++ * means it has the smallest minor_key and it should
++ * replace @tmp as minor_key owner */
++ list_replace_init(&tmp->lk_nodes[dep].ln_major_list,
++ &lck->lk_nodes[dep].ln_major_list);
++ }
++ /* remove the temporary head */
++ list_del(&list);
++
++ out_grant_major:
++ ln_grant_inc(dep, lck->lk_nodes[dep].ln_mode);
++ return 1; /* granted with holding lh_lock */
++
++ out_enqueue:
++ list_del(&list); /* remove temprary head */
++ return htree_node_lock_enqueue(lck, tmp2, dep, wait, event);
++}
++
++/*
++ * release the key of @lck at level @dep, and grant any blocked locks.
++ * caller will still listen on @key if @event is not NULL, which means
++ * caller can see a event (by event_cb) while granting any lock with
++ * the same key at level @dep.
++ * NB: ALWAYS called holding lhead::lh_lock
++ * NB: listener will not block anyone because listening mode is HTREE_LOCK_NL
++ */
++static void
++htree_node_unlock_internal(struct htree_lock_head *lhead,
++ struct htree_lock *curlk, unsigned dep, void *event)
++{
++ struct htree_lock_node *curln = &curlk->lk_nodes[dep];
++ struct htree_lock *grtlk = NULL;
++ struct htree_lock_node *grtln;
++ struct htree_lock *poslk;
++ struct htree_lock *tmplk;
++
++ if (!htree_node_is_granted(curlk, dep))
++ return;
++
++ if (!list_empty(&curln->ln_granted_list)) {
++ /* there is another granted lock */
++ grtlk = list_entry(curln->ln_granted_list.next,
++ struct htree_lock,
++ lk_nodes[dep].ln_granted_list);
++ list_del_init(&curln->ln_granted_list);
++ }
++
++ if (grtlk == NULL && !list_empty(&curln->ln_blocked_list)) {
++ /*
++ * @curlk is the only granted lock, so we confirmed:
++ * a) curln is key owner (attached on major/minor_list),
++ * so if there is any blocked lock, it should be attached
++ * on curln->ln_blocked_list
++ * b) we always can grant the first blocked lock
++ */
++ grtlk = list_entry(curln->ln_blocked_list.next,
++ struct htree_lock,
++ lk_nodes[dep].ln_blocked_list);
++ BUG_ON(grtlk->lk_task == NULL);
++ wake_up_process(grtlk->lk_task);
++ }
++
++ if (event != NULL &&
++ lhead->lh_children[dep].lc_events != HTREE_EVENT_DISABLE) {
++ curln->ln_ev_target = event;
++ curln->ln_mode = HTREE_LOCK_NL; /* listen! */
++ } else {
++ curln->ln_mode = HTREE_LOCK_INVAL;
++ }
++
++ if (grtlk == NULL) { /* I must be the only one locking this key */
++ struct htree_lock_node *tmpln;
++
++ BUG_ON(htree_key_list_empty(curln));
++
++ if (curln->ln_mode == HTREE_LOCK_NL) /* listening */
++ return;
++
++ /* not listening */
++ if (list_empty(&curln->ln_alive_list)) { /* no more listener */
++ htree_key_list_del_init(curln);
++ return;
++ }
++
++ tmpln = list_entry(curln->ln_alive_list.next,
++ struct htree_lock_node, ln_alive_list);
++
++ BUG_ON(tmpln->ln_mode != HTREE_LOCK_NL);
++
++ htree_key_list_replace_init(curln, tmpln);
++ list_del_init(&curln->ln_alive_list);
++
++ return;
++ }
++
++ /* have a granted lock */
++ grtln = &grtlk->lk_nodes[dep];
++ if (!list_empty(&curln->ln_blocked_list)) {
++ /* only key owner can be on both lists */
++ BUG_ON(htree_key_list_empty(curln));
++
++ if (list_empty(&grtln->ln_blocked_list)) {
++ list_add(&grtln->ln_blocked_list,
++ &curln->ln_blocked_list);
++ }
++ list_del_init(&curln->ln_blocked_list);
++ }
++ /*
++ * NB: this is the tricky part:
++ * We have only two modes for child-lock (PR and PW), also,
++ * only owner of the key (attached on major/minor_list) can be on
++ * both blocked_list and granted_list, so @grtlk must be one
++ * of these two cases:
++ *
++ * a) @grtlk is taken from granted_list, which means we've granted
++ * more than one lock so @grtlk has to be PR, the first blocked
++ * lock must be PW and we can't grant it at all.
++ * So even @grtlk is not owner of the key (empty blocked_list),
++ * we don't care because we can't grant any lock.
++ * b) we just grant a new lock which is taken from head of blocked
++ * list, and it should be the first granted lock, and it should
++ * be the first one linked on blocked_list.
++ *
++ * Either way, we can get correct result by iterating blocked_list
++ * of @grtlk, and don't have to bother on how to find out
++ * owner of current key.
++ */
++ list_for_each_entry_safe(poslk, tmplk, &grtln->ln_blocked_list,
++ lk_nodes[dep].ln_blocked_list) {
++ if (grtlk->lk_nodes[dep].ln_mode == HTREE_LOCK_PW ||
++ poslk->lk_nodes[dep].ln_mode == HTREE_LOCK_PW)
++ break;
++ /* grant all readers */
++ list_del_init(&poslk->lk_nodes[dep].ln_blocked_list);
++ list_add(&poslk->lk_nodes[dep].ln_granted_list,
++ &grtln->ln_granted_list);
++
++ BUG_ON(poslk->lk_task == NULL);
++ wake_up_process(poslk->lk_task);
++ }
++
++ /* if @curln is the owner of this key, replace it with @grtln */
++ if (!htree_key_list_empty(curln))
++ htree_key_list_replace_init(curln, grtln);
++
++ if (curln->ln_mode == HTREE_LOCK_INVAL)
++ list_del_init(&curln->ln_alive_list);
++}
++
++/*
++ * it's just wrapper of htree_node_lock_internal, it returns 1 on granted
++ * and 0 only if @wait is false and can't grant it immediately
++ */
++int
++htree_node_lock_try(struct htree_lock *lck, htree_lock_mode_t mode,
++ u32 key, unsigned dep, int wait, void *event)
++{
++ struct htree_lock_head *lhead = lck->lk_head;
++ int rc;
++
++ BUG_ON(dep >= lck->lk_depth);
++ BUG_ON(lck->lk_mode == HTREE_LOCK_INVAL);
++
++ htree_spin_lock(lhead, dep);
++ rc = htree_node_lock_internal(lhead, lck, mode, key, dep, wait, event);
++ if (rc != 0)
++ htree_spin_unlock(lhead, dep);
++ return rc >= 0;
++}
++EXPORT_SYMBOL(htree_node_lock_try);
++
++/* it's wrapper of htree_node_unlock_internal */
++void
++htree_node_unlock(struct htree_lock *lck, unsigned dep, void *event)
++{
++ struct htree_lock_head *lhead = lck->lk_head;
++
++ BUG_ON(dep >= lck->lk_depth);
++ BUG_ON(lck->lk_mode == HTREE_LOCK_INVAL);
++
++ htree_spin_lock(lhead, dep);
++ htree_node_unlock_internal(lhead, lck, dep, event);
++ htree_spin_unlock(lhead, dep);
++}
++EXPORT_SYMBOL(htree_node_unlock);
++
++/* stop listening on child-lock level @dep */
++void
++htree_node_stop_listen(struct htree_lock *lck, unsigned dep)
++{
++ struct htree_lock_node *ln = &lck->lk_nodes[dep];
++ struct htree_lock_node *tmp;
++
++ BUG_ON(htree_node_is_granted(lck, dep));
++ BUG_ON(!list_empty(&ln->ln_blocked_list));
++ BUG_ON(!list_empty(&ln->ln_granted_list));
++
++ if (!htree_node_is_listening(lck, dep))
++ return;
++
++ htree_spin_lock(lck->lk_head, dep);
++ ln->ln_mode = HTREE_LOCK_INVAL;
++ ln->ln_ev_target = NULL;
++
++ if (htree_key_list_empty(ln)) { /* not owner */
++ list_del_init(&ln->ln_alive_list);
++ goto out;
++ }
++
++ /* I'm the owner... */
++ if (list_empty(&ln->ln_alive_list)) { /* no more listener */
++ htree_key_list_del_init(ln);
++ goto out;
++ }
++
++ tmp = list_entry(ln->ln_alive_list.next,
++ struct htree_lock_node, ln_alive_list);
++
++ BUG_ON(tmp->ln_mode != HTREE_LOCK_NL);
++ htree_key_list_replace_init(ln, tmp);
++ list_del_init(&ln->ln_alive_list);
++ out:
++ htree_spin_unlock(lck->lk_head, dep);
++}
++EXPORT_SYMBOL(htree_node_stop_listen);
++
++/* release all child-locks if we have any */
++static void
++htree_node_release_all(struct htree_lock *lck)
++{
++ int i;
++
++ for (i = 0; i < lck->lk_depth; i++) {
++ if (htree_node_is_granted(lck, i))
++ htree_node_unlock(lck, i, NULL);
++ else if (htree_node_is_listening(lck, i))
++ htree_node_stop_listen(lck, i);
++ }
++}
++
++/*
++ * obtain htree lock, it could be blocked inside if there's conflict
++ * with any granted or blocked lock and @wait is true.
++ * NB: ALWAYS called holding lhead::lh_lock
++ */
++static int
++htree_lock_internal(struct htree_lock *lck, int wait)
++{
++ struct htree_lock_head *lhead = lck->lk_head;
++ int granted = 0;
++ int blocked = 0;
++ int i;
++
++ for (i = 0; i < HTREE_LOCK_MAX; i++) {
++ if (lhead->lh_ngranted[i] != 0)
++ granted |= 1 << i;
++ if (lhead->lh_nblocked[i] != 0)
++ blocked |= 1 << i;
++ }
++ if ((htree_lock_compat[lck->lk_mode] & granted) != granted ||
++ (htree_lock_compat[lck->lk_mode] & blocked) != blocked) {
++ /* will block current lock even it just conflicts with any
++ * other blocked lock, so lock like EX wouldn't starve */
++ if (!wait)
++ return -1;
++ lhead->lh_nblocked[lck->lk_mode]++;
++ lk_block_inc(lck->lk_mode);
++
++ lck->lk_task = current;
++ list_add_tail(&lck->lk_blocked_list, &lhead->lh_blocked_list);
++
++ set_current_state(TASK_UNINTERRUPTIBLE);
++ htree_spin_unlock(lhead, HTREE_DEP_ROOT);
++ /* wait to be given the lock */
++ if (lck->lk_task != NULL)
++ schedule();
++ /* granted, no doubt. wake up will set me RUNNING */
++ return 0; /* without lh_lock */
++ }
++ lhead->lh_ngranted[lck->lk_mode]++;
++ lk_grant_inc(lck->lk_mode);
++ return 1;
++}
++
++/* release htree lock. NB: ALWAYS called holding lhead::lh_lock */
++static void
++htree_unlock_internal(struct htree_lock *lck)
++{
++ struct htree_lock_head *lhead = lck->lk_head;
++ struct htree_lock *tmp;
++ struct htree_lock *tmp2;
++ int granted = 0;
++ int i;
++
++ BUG_ON(lhead->lh_ngranted[lck->lk_mode] == 0);
++
++ lhead->lh_ngranted[lck->lk_mode]--;
++ lck->lk_mode = HTREE_LOCK_INVAL;
++
++ for (i = 0; i < HTREE_LOCK_MAX; i++) {
++ if (lhead->lh_ngranted[i] != 0)
++ granted |= 1 << i;
++ }
++ list_for_each_entry_safe(tmp, tmp2,
++ &lhead->lh_blocked_list, lk_blocked_list) {
++ /* conflict with any granted lock? */
++ if ((htree_lock_compat[tmp->lk_mode] & granted) != granted)
++ break;
++
++ list_del_init(&tmp->lk_blocked_list);
++
++ BUG_ON(lhead->lh_nblocked[tmp->lk_mode] == 0);
++
++ lhead->lh_nblocked[tmp->lk_mode]--;
++ lhead->lh_ngranted[tmp->lk_mode]++;
++ granted |= 1 << tmp->lk_mode;
++
++ BUG_ON(tmp->lk_task == NULL);
++ wake_up_process(tmp->lk_task);
++ }
++}
++
++/* it's wrapper of htree_lock_internal and exported interface.
++ * It always return 1 with granted lock if @wait is true, it can return 0
++ * if @wait is false and locking request can't be granted immediately */
++int
++htree_lock_try(struct htree_lock *lck, struct htree_lock_head *lhead,
++ htree_lock_mode_t mode, int wait)
++{
++ int rc;
++
++ BUG_ON(lck->lk_depth > lhead->lh_depth);
++ BUG_ON(lck->lk_head != NULL);
++ BUG_ON(lck->lk_task != NULL);
++
++ lck->lk_head = lhead;
++ lck->lk_mode = mode;
++
++ htree_spin_lock(lhead, HTREE_DEP_ROOT);
++ rc = htree_lock_internal(lck, wait);
++ if (rc != 0)
++ htree_spin_unlock(lhead, HTREE_DEP_ROOT);
++ return rc >= 0;
++}
++EXPORT_SYMBOL(htree_lock_try);
++
++/* it's wrapper of htree_unlock_internal and exported interface.
++ * It will release all htree_node_locks and htree_lock */
++void
++htree_unlock(struct htree_lock *lck)
++{
++ BUG_ON(lck->lk_head == NULL);
++ BUG_ON(lck->lk_mode == HTREE_LOCK_INVAL);
++
++ htree_node_release_all(lck);
++
++ htree_spin_lock(lck->lk_head, HTREE_DEP_ROOT);
++ htree_unlock_internal(lck);
++ htree_spin_unlock(lck->lk_head, HTREE_DEP_ROOT);
++ lck->lk_head = NULL;
++ lck->lk_task = NULL;
++}
++EXPORT_SYMBOL(htree_unlock);
++
++/* change lock mode */
++void
++htree_change_mode(struct htree_lock *lck, htree_lock_mode_t mode)
++{
++ BUG_ON(lck->lk_mode == HTREE_LOCK_INVAL);
++ lck->lk_mode = mode;
++}
++EXPORT_SYMBOL(htree_change_mode);
++
++/* release htree lock, and lock it again with new mode.
++ * This function will first release all htree_node_locks and htree_lock,
++ * then try to gain htree_lock with new @mode.
++ * It always return 1 with granted lock if @wait is true, it can return 0
++ * if @wait is false and locking request can't be granted immediately */
++int
++htree_change_lock_try(struct htree_lock *lck, htree_lock_mode_t mode, int wait)
++{
++ struct htree_lock_head *lhead = lck->lk_head;
++ int rc;
++
++ BUG_ON(lhead == NULL);
++ BUG_ON(lck->lk_mode == mode);
++ BUG_ON(lck->lk_mode == HTREE_LOCK_INVAL || mode == HTREE_LOCK_INVAL);
++
++ htree_node_release_all(lck);
++
++ htree_spin_lock(lhead, HTREE_DEP_ROOT);
++ htree_unlock_internal(lck);
++ lck->lk_mode = mode;
++ rc = htree_lock_internal(lck, wait);
++ if (rc != 0)
++ htree_spin_unlock(lhead, HTREE_DEP_ROOT);
++ return rc >= 0;
++}
++EXPORT_SYMBOL(htree_change_lock_try);
++
++/* create a htree_lock head with @depth levels (number of child-locks),
++ * it is a per resoruce structure */
++struct htree_lock_head *
++htree_lock_head_alloc(unsigned depth, unsigned hbits, unsigned priv)
++{
++ struct htree_lock_head *lhead;
++ int i;
++
++ if (depth > HTREE_LOCK_DEP_MAX) {
++ printk(KERN_ERR "%d is larger than max htree_lock depth %d\n",
++ depth, HTREE_LOCK_DEP_MAX);
++ return NULL;
++ }
++
++ lhead = kzalloc(offsetof(struct htree_lock_head,
++ lh_children[depth]) + priv, GFP_NOFS);
++ if (lhead == NULL)
++ return NULL;
++
++ if (hbits < HTREE_HBITS_MIN)
++ lhead->lh_hbits = HTREE_HBITS_MIN;
++ else if (hbits > HTREE_HBITS_MAX)
++ lhead->lh_hbits = HTREE_HBITS_MAX;
++
++ lhead->lh_lock = 0;
++ lhead->lh_depth = depth;
++ INIT_LIST_HEAD(&lhead->lh_blocked_list);
++ if (priv > 0) {
++ lhead->lh_private = (void *)lhead +
++ offsetof(struct htree_lock_head, lh_children[depth]);
++ }
++
++ for (i = 0; i < depth; i++) {
++ INIT_LIST_HEAD(&lhead->lh_children[i].lc_list);
++ lhead->lh_children[i].lc_events = HTREE_EVENT_DISABLE;
++ }
++ return lhead;
++}
++EXPORT_SYMBOL(htree_lock_head_alloc);
++
++/* free the htree_lock head */
++void
++htree_lock_head_free(struct htree_lock_head *lhead)
++{
++ int i;
++
++ BUG_ON(!list_empty(&lhead->lh_blocked_list));
++ for (i = 0; i < lhead->lh_depth; i++)
++ BUG_ON(!list_empty(&lhead->lh_children[i].lc_list));
++ kfree(lhead);
++}
++EXPORT_SYMBOL(htree_lock_head_free);
++
++/* register event callback for @events of child-lock at level @dep */
++void
++htree_lock_event_attach(struct htree_lock_head *lhead, unsigned dep,
++ unsigned events, htree_event_cb_t callback)
++{
++ BUG_ON(lhead->lh_depth <= dep);
++ lhead->lh_children[dep].lc_events = events;
++ lhead->lh_children[dep].lc_callback = callback;
++}
++EXPORT_SYMBOL(htree_lock_event_attach);
++
++/* allocate a htree_lock, which is per-thread structure, @pbytes is some
++ * extra-bytes as private data for caller */
++struct htree_lock *
++htree_lock_alloc(unsigned depth, unsigned pbytes)
++{
++ struct htree_lock *lck;
++ int i = offsetof(struct htree_lock, lk_nodes[depth]);
++
++ if (depth > HTREE_LOCK_DEP_MAX) {
++ printk(KERN_ERR "%d is larger than max htree_lock depth %d\n",
++ depth, HTREE_LOCK_DEP_MAX);
++ return NULL;
++ }
++ lck = kzalloc(i + pbytes, GFP_NOFS);
++ if (lck == NULL)
++ return NULL;
++
++ if (pbytes != 0)
++ lck->lk_private = (void *)lck + i;
++ lck->lk_mode = HTREE_LOCK_INVAL;
++ lck->lk_depth = depth;
++ INIT_LIST_HEAD(&lck->lk_blocked_list);
++
++ for (i = 0; i < depth; i++) {
++ struct htree_lock_node *node = &lck->lk_nodes[i];
++
++ node->ln_mode = HTREE_LOCK_INVAL;
++ INIT_LIST_HEAD(&node->ln_major_list);
++ INIT_LIST_HEAD(&node->ln_minor_list);
++ INIT_LIST_HEAD(&node->ln_alive_list);
++ INIT_LIST_HEAD(&node->ln_blocked_list);
++ INIT_LIST_HEAD(&node->ln_granted_list);
++ }
++
++ return lck;
++}
++EXPORT_SYMBOL(htree_lock_alloc);
++
++/* free htree_lock node */
++void
++htree_lock_free(struct htree_lock *lck)
++{
++ BUG_ON(lck->lk_mode != HTREE_LOCK_INVAL);
++ kfree(lck);
++}
++EXPORT_SYMBOL(htree_lock_free);
+--- linux-2.6.32-131.6.1/fs/ext4/ext4.h 2011-10-06 20:10:49.000000000 +0800
++++ linux-2.6.32-131.6.1-pdo/fs/ext4/ext4.h 2011-12-08 18:25:00.000000000 +0800
+@@ -28,6 +28,7 @@
+ #include <linux/mutex.h>
+ #include <linux/timer.h>
+ #include <linux/wait.h>
++#include <linux/htree_lock.h>
+ #include <linux/blockgroup_lock.h>
+ #include <linux/percpu_counter.h>
+ #ifdef __KERNEL__
+@@ -1277,6 +1278,7 @@ EXT4_INODE_BIT_FNS(state, state_flags)
+ #define EXT4_FEATURE_INCOMPAT_MMP 0x0100
+ #define EXT4_FEATURE_INCOMPAT_FLEX_BG 0x0200
+ #define EXT4_FEATURE_INCOMPAT_DIRDATA 0x1000
++#define EXT4_FEATURE_INCOMPAT_LARGEDIR 0x4000
+
+ #define EXT4_FEATURE_COMPAT_SUPP EXT2_FEATURE_COMPAT_EXT_ATTR
+ #define EXT4_FEATURE_INCOMPAT_SUPP (EXT4_FEATURE_INCOMPAT_FILETYPE| \
+@@ -1286,7 +1288,8 @@ EXT4_INODE_BIT_FNS(state, state_flags)
+ EXT4_FEATURE_INCOMPAT_64BIT| \
+ EXT4_FEATURE_INCOMPAT_FLEX_BG| \
+ EXT4_FEATURE_INCOMPAT_MMP| \
+- EXT4_FEATURE_INCOMPAT_DIRDATA)
++ EXT4_FEATURE_INCOMPAT_DIRDATA| \
++ EXT4_FEATURE_INCOMPAT_LARGEDIR)
+
+ #define EXT4_FEATURE_RO_COMPAT_SUPP (EXT4_FEATURE_RO_COMPAT_SPARSE_SUPER| \
+ EXT4_FEATURE_RO_COMPAT_LARGE_FILE| \
+@@ -1536,6 +1539,76 @@ ext4_group_first_block_no(struct super_b
+ */
+ #define ERR_BAD_DX_DIR -75000
+
++/* htree levels for ext4 */
++#define EXT4_HTREE_LEVEL_COMPAT 2
++#define EXT4_HTREE_LEVEL 3
++
++static inline int
++ext4_dir_htree_level(struct super_block *sb)
++{
++ return EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_LARGEDIR) ?
++ EXT4_HTREE_LEVEL : EXT4_HTREE_LEVEL_COMPAT;
++}
++
++/* assume name-hash is protected by upper layer */
++#define EXT4_HTREE_LOCK_HASH 0
++
++enum ext4_pdo_lk_types {
++#if EXT4_HTREE_LOCK_HASH
++ EXT4_LK_HASH,
++#endif
++ EXT4_LK_DX, /* index block */
++ EXT4_LK_DE, /* directory entry block */
++ EXT4_LK_SPIN, /* spinlock */
++ EXT4_LK_MAX,
++};
++
++/* read-only bit */
++#define EXT4_LB_RO(b) (1 << (b))
++/* read + write, high bits for writer */
++#define EXT4_LB_RW(b) ((1 << (b)) | (1 << (EXT4_LK_MAX + (b))))
++
++enum ext4_pdo_lock_bits {
++ /* DX lock bits */
++ EXT4_LB_DX_RO = EXT4_LB_RO(EXT4_LK_DX),
++ EXT4_LB_DX = EXT4_LB_RW(EXT4_LK_DX),
++ /* DE lock bits */
++ EXT4_LB_DE_RO = EXT4_LB_RO(EXT4_LK_DE),
++ EXT4_LB_DE = EXT4_LB_RW(EXT4_LK_DE),
++ /* DX spinlock bits */
++ EXT4_LB_SPIN_RO = EXT4_LB_RO(EXT4_LK_SPIN),
++ EXT4_LB_SPIN = EXT4_LB_RW(EXT4_LK_SPIN),
++ /* accurate searching */
++ EXT4_LB_EXACT = EXT4_LB_RO(EXT4_LK_MAX << 1),
++};
++
++enum ext4_pdo_lock_opc {
++ /* external */
++ EXT4_HLOCK_READDIR = (EXT4_LB_DE_RO | EXT4_LB_DX_RO),
++ EXT4_HLOCK_LOOKUP = (EXT4_LB_DE_RO | EXT4_LB_SPIN_RO |
++ EXT4_LB_EXACT),
++ EXT4_HLOCK_DEL = (EXT4_LB_DE | EXT4_LB_SPIN_RO |
++ EXT4_LB_EXACT),
++ EXT4_HLOCK_ADD = (EXT4_LB_DE | EXT4_LB_SPIN_RO),
++
++ /* internal */
++ EXT4_HLOCK_LOOKUP_SAFE = (EXT4_LB_DE_RO | EXT4_LB_DX_RO |
++ EXT4_LB_EXACT),
++ EXT4_HLOCK_DEL_SAFE = (EXT4_LB_DE | EXT4_LB_DX_RO | EXT4_LB_EXACT),
++ EXT4_HLOCK_SPLIT = (EXT4_LB_DE | EXT4_LB_DX | EXT4_LB_SPIN),
++};
++
++extern struct htree_lock_head *ext4_htree_lock_head_alloc(unsigned hbits);
++#define ext4_htree_lock_head_free(lhead) htree_lock_head_free(lhead)
++
++extern struct htree_lock *ext4_htree_lock_alloc(void);
++#define ext4_htree_lock_free(lck) htree_lock_free(lck)
++
++extern void ext4_htree_lock(struct htree_lock *lck,
++ struct htree_lock_head *lhead,
++ struct inode *dir, unsigned flags);
++#define ext4_htree_unlock(lck) htree_unlock(lck)
++
+ void ext4_get_group_no_and_offset(struct super_block *sb, ext4_fsblk_t blocknr,
+ ext4_group_t *blockgrpp, ext4_grpblk_t *offsetp);
+
+@@ -1769,14 +1842,16 @@ extern int ext4_htree_fill_tree(struct f
+ extern struct inode *ext4_create_inode(handle_t *handle,
+ struct inode * dir, int mode);
+ extern int ext4_add_entry(handle_t *handle, struct dentry *dentry,
+- struct inode *inode);
++ struct inode *inode, struct htree_lock *lck);
+ extern int ext4_delete_entry(handle_t *handle, struct inode * dir,
+ struct ext4_dir_entry_2 * de_del,
+ struct buffer_head * bh);
+ extern struct buffer_head * ext4_find_entry(struct inode *dir,
+ const struct qstr *d_name,
+- struct ext4_dir_entry_2 ** res_dir);
+-#define ll_ext4_find_entry(inode, dentry, res_dir) ext4_find_entry(inode, &(dentry)->d_name, res_dir)
++ struct ext4_dir_entry_2 **res_dir,
++ struct htree_lock *lck);
++#define ll_ext4_find_entry(inode, dentry, res_dir, lck) \
++ ext4_find_entry(inode, &(dentry)->d_name, res_dir, lck)
+ extern int ext4_add_dot_dotdot(handle_t *handle, struct inode *dir,
+ struct inode *inode, const void *, const void *);
+ extern struct buffer_head *ext4_append(handle_t *handle,
+@@ -1893,13 +1968,15 @@ static inline void ext4_r_blocks_count_s
+ es->s_r_blocks_count_hi = cpu_to_le32(blk >> 32);
+ }
+
+-static inline loff_t ext4_isize(struct ext4_inode *raw_inode)
++static inline loff_t ext4_isize(struct super_block *sb,
++ struct ext4_inode *raw_inode)
+ {
+- if (S_ISREG(le16_to_cpu(raw_inode->i_mode)))
++ if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_LARGEDIR) ||
++ S_ISREG(le16_to_cpu(raw_inode->i_mode)))
+ return ((loff_t)le32_to_cpu(raw_inode->i_size_high) << 32) |
+ le32_to_cpu(raw_inode->i_size_lo);
+- else
+- return (loff_t) le32_to_cpu(raw_inode->i_size_lo);
++
++ return (loff_t) le32_to_cpu(raw_inode->i_size_lo);
+ }
+
+ static inline void ext4_isize_set(struct ext4_inode *raw_inode, loff_t i_size)
+--- linux-2.6.32-131.6.1/fs/ext4/namei.c 2011-10-06 20:10:49.000000000 +0800
++++ linux-2.6.32-131.6.1-pdo/fs/ext4/namei.c 2011-12-14 22:55:28.000000000 +0800
+@@ -176,7 +176,7 @@ static struct dx_frame *dx_probe(const s
+ struct inode *dir,
+ struct dx_hash_info *hinfo,
+ struct dx_frame *frame,
+- int *err);
++ struct htree_lock *lck, int *err);
+ static void dx_release(struct dx_frame *frames);
+ static int dx_make_map(struct ext4_dir_entry_2 *de, unsigned blocksize,
+ struct dx_hash_info *hinfo, struct dx_map_entry map[]);
+@@ -189,13 +189,13 @@ static void dx_insert_block(struct dx_fr
+ static int ext4_htree_next_block(struct inode *dir, __u32 hash,
+ struct dx_frame *frame,
+ struct dx_frame *frames,
+- __u32 *start_hash);
++ __u32 *start_hash, struct htree_lock *lck);
+ static struct buffer_head * ext4_dx_find_entry(struct inode *dir,
+ const struct qstr *d_name,
+ struct ext4_dir_entry_2 **res_dir,
+- int *err);
++ struct htree_lock *lck, int *err);
+ static int ext4_dx_add_entry(handle_t *handle, struct dentry *dentry,
+- struct inode *inode);
++ struct inode *inode, struct htree_lock *lck);
+
+ /*
+ * p is at least 6 bytes before the end of page
+@@ -225,7 +225,7 @@ struct dx_root_info * dx_get_dx_info(str
+
+ static inline ext4_lblk_t dx_get_block(struct dx_entry *entry)
+ {
+- return le32_to_cpu(entry->block) & 0x00ffffff;
++ return le32_to_cpu(entry->block) & 0x0fffffff;
+ }
+
+ static inline void dx_set_block(struct dx_entry *entry, ext4_lblk_t value)
+@@ -368,6 +368,223 @@ struct stats dx_show_entries(struct dx_h
+ }
+ #endif /* DX_DEBUG */
+
++/* private data for htree_lock */
++struct ext4_dir_lock_data {
++ unsigned ld_flags; /* bits-map for lock types */
++ unsigned ld_count; /* # entries of the last DX block */
++ struct dx_entry ld_at_entry; /* copy of leaf dx_entry */
++ struct dx_entry *ld_at; /* position of leaf dx_entry */
++};
++
++#define ext4_htree_lock_data(l) ((struct ext4_dir_lock_data *)(l)->lk_private)
++
++/* NB: ext4_lblk_t is 32 bits so we use high bits to identify invalid blk */
++#define EXT4_HTREE_NODE_CHANGED (0xcafeULL << 32)
++
++static void ext4_htree_event_cb(void *target, void *event)
++{
++ u64 *block = (u64 *)target;
++
++ if (*block == dx_get_block((struct dx_entry *)event))
++ *block = EXT4_HTREE_NODE_CHANGED;
++}
++
++struct htree_lock_head *ext4_htree_lock_head_alloc(unsigned hbits)
++{
++ struct htree_lock_head *lhead;
++
++ lhead = htree_lock_head_alloc(EXT4_LK_MAX, hbits, 0);
++ if (lhead != NULL) {
++ htree_lock_event_attach(lhead, EXT4_LK_SPIN, HTREE_EVENT_WR,
++ ext4_htree_event_cb);
++ }
++ return lhead;
++}
++EXPORT_SYMBOL(ext4_htree_lock_head_alloc);
++
++struct htree_lock *ext4_htree_lock_alloc(void)
++{
++ return htree_lock_alloc(EXT4_LK_MAX,
++ sizeof(struct ext4_dir_lock_data));
++}
++EXPORT_SYMBOL(ext4_htree_lock_alloc);
++
++static htree_lock_mode_t ext4_htree_mode(unsigned flags)
++{
++ switch (flags) {
++ default: /* 0 or unknown flags require EX lock */
++ return HTREE_LOCK_EX;
++ case EXT4_HLOCK_READDIR:
++ return HTREE_LOCK_PR;
++ case EXT4_HLOCK_LOOKUP:
++ return HTREE_LOCK_CR;
++ case EXT4_HLOCK_DEL:
++ case EXT4_HLOCK_ADD:
++ return HTREE_LOCK_CW;
++ }
++}
++
++/* return PR for read-only operations, otherwise return EX */
++static inline htree_lock_mode_t ext4_htree_safe_mode(unsigned flags)
++{
++ int writer = (flags & EXT4_LB_DE) == EXT4_LB_DE;
++
++ /* 0 requires EX lock */
++ return (flags == 0 || writer) ? HTREE_LOCK_EX : HTREE_LOCK_PR;
++}
++
++static int ext4_htree_safe_locked(struct htree_lock *lck)
++{
++ int writer;
++
++ if (lck == NULL || lck->lk_mode == HTREE_LOCK_EX)
++ return 1;
++
++ writer = (ext4_htree_lock_data(lck)->ld_flags & EXT4_LB_DE) ==
++ EXT4_LB_DE;
++ if (writer) /* all readers & writers are excluded? */
++ return lck->lk_mode == HTREE_LOCK_EX;
++
++ /* all writers are excluded? */
++ return lck->lk_mode == HTREE_LOCK_PR ||
++ lck->lk_mode == HTREE_LOCK_PW ||
++ lck->lk_mode == HTREE_LOCK_EX;
++}
++
++/* relock htree_lock with EX mode if it's change operation, otherwise
++ * relock it with PR mode. It's noop if PDO is disabled. */
++static void ext4_htree_safe_relock(struct htree_lock *lck)
++{
++ if (!ext4_htree_safe_locked(lck)) {
++ unsigned flags = ext4_htree_lock_data(lck)->ld_flags;
++
++ htree_change_lock(lck, ext4_htree_safe_mode(flags));
++ }
++}
++
++void ext4_htree_lock(struct htree_lock *lck, struct htree_lock_head *lhead,
++ struct inode *dir, unsigned flags)
++{
++ htree_lock_mode_t mode = is_dx(dir) ? ext4_htree_mode(flags) :
++ ext4_htree_safe_mode(flags);
++
++ ext4_htree_lock_data(lck)->ld_flags = flags;
++ htree_lock(lck, lhead, mode);
++ if (!is_dx(dir))
++ ext4_htree_safe_relock(lck); /* make sure it's safe locked */
++}
++EXPORT_SYMBOL(ext4_htree_lock);
++
++static int ext4_htree_node_lock(struct htree_lock *lck, struct dx_entry *at,
++ unsigned lmask, int wait, void *ev)
++{
++ u32 key = (at == NULL) ? 0 : dx_get_block(at);
++ u32 mode;
++
++ /* NOOP if htree is well protected or caller doesn't require the lock */
++ if (ext4_htree_safe_locked(lck) ||
++ !(ext4_htree_lock_data(lck)->ld_flags & lmask))
++ return 1;
++
++ mode = (ext4_htree_lock_data(lck)->ld_flags & lmask) == lmask ?
++ HTREE_LOCK_PW : HTREE_LOCK_PR;
++ while (1) {
++ if (htree_node_lock_try(lck, mode, key, ffz(~lmask), wait, ev))
++ return 1;
++ if (!(lmask & EXT4_LB_SPIN)) /* not a spinlock */
++ return 0;
++ cpu_relax(); /* spin until granted */
++ }
++}
++
++static int ext4_htree_node_locked(struct htree_lock *lck, unsigned lmask)
++{
++ return ext4_htree_safe_locked(lck) ||
++ htree_node_is_granted(lck, ffz(~lmask));
++}
++
++static void ext4_htree_node_unlock(struct htree_lock *lck,
++ unsigned lmask, void *buf)
++{
++ /* NB: it's safe to call mutiple times or even it's not locked */
++ if (!ext4_htree_safe_locked(lck) &&
++ htree_node_is_granted(lck, ffz(~lmask)))
++ htree_node_unlock(lck, ffz(~lmask), buf);
++}
++
++#define ext4_htree_dx_lock(lck, key) \
++ ext4_htree_node_lock(lck, key, EXT4_LB_DX, 1, NULL)
++#define ext4_htree_dx_lock_try(lck, key) \
++ ext4_htree_node_lock(lck, key, EXT4_LB_DX, 0, NULL)
++#define ext4_htree_dx_unlock(lck) \
++ ext4_htree_node_unlock(lck, EXT4_LB_DX, NULL)
++#define ext4_htree_dx_locked(lck) \
++ ext4_htree_node_locked(lck, EXT4_LB_DX)
++
++static void ext4_htree_dx_need_lock(struct htree_lock *lck)
++{
++ struct ext4_dir_lock_data *ld;
++
++ if (ext4_htree_safe_locked(lck))
++ return;
++
++ ld = ext4_htree_lock_data(lck);
++ switch (ld->ld_flags) {
++ default:
++ return;
++ case EXT4_HLOCK_LOOKUP:
++ ld->ld_flags = EXT4_HLOCK_LOOKUP_SAFE;
++ return;
++ case EXT4_HLOCK_DEL:
++ ld->ld_flags = EXT4_HLOCK_DEL_SAFE;
++ return;
++ case EXT4_HLOCK_ADD:
++ ld->ld_flags = EXT4_HLOCK_SPLIT;
++ return;
++ }
++}
++
++#define ext4_htree_de_lock(lck, key) \
++ ext4_htree_node_lock(lck, key, EXT4_LB_DE, 1, NULL)
++#define ext4_htree_de_unlock(lck) \
++ ext4_htree_node_unlock(lck, EXT4_LB_DE, NULL)
++
++#define ext4_htree_spin_lock(lck, key, event) \
++ ext4_htree_node_lock(lck, key, EXT4_LB_SPIN, 0, event)
++#define ext4_htree_spin_unlock(lck) \
++ ext4_htree_node_unlock(lck, EXT4_LB_SPIN, NULL)
++#define ext4_htree_spin_unlock_listen(lck, p) \
++ ext4_htree_node_unlock(lck, EXT4_LB_SPIN, p)
++
++static void ext4_htree_spin_stop_listen(struct htree_lock *lck)
++{
++ if (!ext4_htree_safe_locked(lck) &&
++ htree_node_is_listening(lck, ffz(~EXT4_LB_SPIN)))
++ htree_node_stop_listen(lck, ffz(~EXT4_LB_SPIN));
++}
++
++enum {
++ DX_HASH_COL_IGNORE, /* ignore collision while probing frames */
++ DX_HASH_COL_YES, /* there is collision and it does matter */
++ DX_HASH_COL_NO, /* there is no collision */
++};
++
++static int dx_probe_hash_collision(struct htree_lock *lck,
++ struct dx_entry *entries,
++ struct dx_entry *at, u32 hash)
++{
++ if (!(ext4_htree_lock_data(lck)->ld_flags & EXT4_LB_EXACT)) {
++ return DX_HASH_COL_IGNORE; /* don't care about collision */
++
++ } else if (at == entries + dx_get_count(entries) - 1) {
++ return DX_HASH_COL_IGNORE; /* not in any leaf of this DX */
++
++ } else { /* hash collision? */
++ return ((dx_get_hash(at + 1) & ~1) == hash) ?
++ DX_HASH_COL_YES : DX_HASH_COL_NO;
++ }
++}
++
+ /*
+ * Probe for a directory leaf block to search.
+ *
+@@ -379,16 +596,17 @@ struct stats dx_show_entries(struct dx_h
+ */
+ static struct dx_frame *
+ dx_probe(const struct qstr *d_name, struct inode *dir,
+- struct dx_hash_info *hinfo, struct dx_frame *frame_in, int *err)
++ struct dx_hash_info *hinfo, struct dx_frame *frame_in,
++ struct htree_lock *lck, int *err)
+ {
+ unsigned count, indirect;
+- struct dx_entry *at, *entries, *p, *q, *m;
++ struct dx_entry *at, *entries, *p, *q, *m, *dx = NULL;
+ struct dx_root_info * info;
+ struct buffer_head *bh;
+ struct dx_frame *frame = frame_in;
+ u32 hash;
+
+- frame->bh = NULL;
++ memset(frame_in, 0, EXT4_HTREE_LEVEL * sizeof(frame_in[0]));
+ if (!(bh = ext4_bread (NULL,dir, 0, 0, err)))
+ goto fail;
+
+@@ -418,9 +636,16 @@ dx_probe(const struct qstr *d_name, stru
+ goto fail;
+ }
+
+- if ((indirect = info->indirect_levels) > 1) {
+- ext4_warning(dir->i_sb, "Unimplemented inode hash depth: %#06x",
+- info->indirect_levels);
++ indirect = info->indirect_levels;
++ if (indirect >= ext4_dir_htree_level(dir->i_sb)) {
++ ext4_warning(dir->i_sb,
++ "Directory (ino: %lu) htree depth %#06x exceed "
++ "supported value", dir->i_ino,
++ ext4_dir_htree_level(dir->i_sb));
++ if (ext4_dir_htree_level(dir->i_sb) < EXT4_HTREE_LEVEL) {
++ ext4_warning(dir->i_sb, "Enable large directory "
++ "feature to access it");
++ }
+ brelse(bh);
+ *err = ERR_BAD_DX_DIR;
+ goto fail;
+@@ -440,8 +665,15 @@ dx_probe(const struct qstr *d_name, stru
+ dxtrace(printk("Look up %x", hash));
+ while (1)
+ {
++ if (indirect == 0) { /* the last index level */
++ /* NB: ext4_htree_dx_lock() could be noop if
++ * DX-lock flag is not set for current operation */
++ ext4_htree_dx_lock(lck, dx);
++ ext4_htree_spin_lock(lck, dx, NULL);
++ }
+ count = dx_get_count(entries);
+- if (!count || count > dx_get_limit(entries)) {
++ if (count == 0 || count > dx_get_limit(entries)) {
++ ext4_htree_spin_unlock(lck); /* release spin */
+ ext4_warning(dir->i_sb,
+ "dx entry: no count or count > limit");
+ brelse(bh);
+@@ -482,9 +714,73 @@ dx_probe(const struct qstr *d_name, stru
+ frame->bh = bh;
+ frame->entries = entries;
+ frame->at = at;
+- if (!indirect--) return frame;
++
++ if (indirect == 0) { /* the last index level */
++ struct ext4_dir_lock_data *ld;
++ u64 myblock;
++
++ /* By default we only lock DE-block, however, we will
++ * also lock the last level DX-block if:
++ * a) there is hash collision
++ * we will set DX-lock flag (a few lines below)
++ * and redo to lock DX-block
++ * see detail in dx_probe_hash_collision()
++ * b) it's a retry from splitting
++ * we need to lock the last level DX-block so nobody
++ * else can split any leaf blocks under the same
++ * DX-block, see detail in ext4_dx_add_entry()
++ */
++ if (ext4_htree_dx_locked(lck)) {
++ /* DX-block is locked, just lock DE-block
++ * and return */
++ ext4_htree_spin_unlock(lck);
++ if (!ext4_htree_safe_locked(lck))
++ ext4_htree_de_lock(lck, frame->at);
++ return frame;
++ }
++ /* it's pdirop and no DX lock */
++ if (dx_probe_hash_collision(lck, entries, at, hash) ==
++ DX_HASH_COL_YES) {
++ /* found hash collision, set DX-lock flag
++ * and retry to abtain DX-lock */
++ ext4_htree_spin_unlock(lck);
++ ext4_htree_dx_need_lock(lck);
++ continue;
++ }
++ ld = ext4_htree_lock_data(lck);
++ /* because I don't lock DX, so @at can't be trusted
++ * after I release spinlock so I have to save it */
++ ld->ld_at = at;
++ ld->ld_at_entry = *at;
++ ld->ld_count = dx_get_count(entries);
++
++ frame->at = &ld->ld_at_entry;
++ myblock = dx_get_block(at);
++
++ /* NB: ordering locking */
++ ext4_htree_spin_unlock_listen(lck, &myblock);
++ /* other thread can split this DE-block because:
++ * a) I don't have lock for the DE-block yet
++ * b) I released spinlock on DX-block
++ * if it happened I can detect it by listening
++ * splitting event on this DE-block */
++ ext4_htree_de_lock(lck, frame->at);
++ ext4_htree_spin_stop_listen(lck);
++
++ if (myblock == EXT4_HTREE_NODE_CHANGED) {
++ /* someone split this DE-block before
++ * I locked it, I need to retry and lock
++ * valid DE-block */
++ ext4_htree_de_unlock(lck);
++ continue;
++ }
++ return frame;
++ }
++ dx = at;
++ indirect--;
+ if (!(bh = ext4_bread (NULL,dir, dx_get_block(at), 0, err)))
+ goto fail2;
++
+ at = entries = ((struct dx_node *) bh->b_data)->entries;
+ if (dx_get_limit(entries) != dx_node_limit (dir)) {
+ ext4_warning(dir->i_sb,
+@@ -512,13 +808,18 @@ fail:
+ static void dx_release (struct dx_frame *frames)
+ {
+ struct dx_root_info *info;
++ int i;
++
+ if (frames[0].bh == NULL)
+ return;
+
+ info = dx_get_dx_info((struct ext4_dir_entry_2*)frames[0].bh->b_data);
+- if (info->indirect_levels)
+- brelse(frames[1].bh);
+- brelse(frames[0].bh);
++ for (i = 0; i <= info->indirect_levels; i++) {
++ if (frames[i].bh == NULL)
++ break;
++ brelse(frames[i].bh);
++ frames[i].bh = NULL;
++ }
+ }
+
+ /*
+@@ -541,7 +842,7 @@ static void dx_release (struct dx_frame
+ static int ext4_htree_next_block(struct inode *dir, __u32 hash,
+ struct dx_frame *frame,
+ struct dx_frame *frames,
+- __u32 *start_hash)
++ __u32 *start_hash, struct htree_lock *lck)
+ {
+ struct dx_frame *p;
+ struct buffer_head *bh;
+@@ -556,12 +857,22 @@ static int ext4_htree_next_block(struct
+ * this loop, num_frames indicates the number of interior
+ * nodes need to be read.
+ */
++ ext4_htree_de_unlock(lck);
+ while (1) {
+- if (++(p->at) < p->entries + dx_get_count(p->entries))
+- break;
++ if (num_frames > 0 || ext4_htree_dx_locked(lck)) {
++ /* num_frames > 0 :
++ * DX block
++ * ext4_htree_dx_locked:
++ * frame->at is reliable pointer returned by dx_probe,
++ * otherwise dx_probe already knew no collision */
++ if (++(p->at) < p->entries + dx_get_count(p->entries))
++ break;
++ }
+ if (p == frames)
+ return 0;
+ num_frames++;
++ if (num_frames == 1)
++ ext4_htree_dx_unlock(lck);
+ p--;
+ }
+
+@@ -584,6 +895,13 @@ static int ext4_htree_next_block(struct
+ * block so no check is necessary
+ */
+ while (num_frames--) {
++ if (num_frames == 0) {
++ /* it's not always necessary, we just don't want to
++ * detect hash collision again */
++ ext4_htree_dx_need_lock(lck);
++ ext4_htree_dx_lock(lck, p->at);
++ }
++
+ if (!(bh = ext4_bread(NULL, dir, dx_get_block(p->at),
+ 0, &err)))
+ return err; /* Failure */
+@@ -592,6 +910,7 @@ static int ext4_htree_next_block(struct
+ p->bh = bh;
+ p->at = p->entries = ((struct dx_node *) bh->b_data)->entries;
+ }
++ ext4_htree_de_lock(lck, p->at);
+ return 1;
+ }
+
+@@ -661,7 +980,7 @@ int ext4_htree_fill_tree(struct file *di
+ {
+ struct dx_hash_info hinfo;
+ struct ext4_dir_entry_2 *de;
+- struct dx_frame frames[2], *frame;
++ struct dx_frame frames[EXT4_HTREE_LEVEL], *frame;
+ struct inode *dir;
+ ext4_lblk_t block;
+ int count = 0;
+@@ -684,10 +1003,10 @@ int ext4_htree_fill_tree(struct file *di
+ }
+ hinfo.hash = start_hash;
+ hinfo.minor_hash = 0;
+- frame = dx_probe(NULL, dir, &hinfo, frames, &err);
++ /* assume it's PR locked */
++ frame = dx_probe(NULL, dir, &hinfo, frames, NULL, &err);
+ if (!frame)
+ return err;
+-
+ /* Add '.' and '..' from the htree header */
+ if (!start_hash && !start_minor_hash) {
+ de = (struct ext4_dir_entry_2 *) frames[0].bh->b_data;
+@@ -714,7 +1033,7 @@ int ext4_htree_fill_tree(struct file *di
+ count += ret;
+ hashval = ~0;
+ ret = ext4_htree_next_block(dir, HASH_NB_ALWAYS,
+- frame, frames, &hashval);
++ frame, frames, &hashval, NULL);
+ *next_hash = hashval;
+ if (ret < 0) {
+ err = ret;
+@@ -814,9 +1133,17 @@ static void dx_insert_block(struct dx_fr
+
+ static void ext4_update_dx_flag(struct inode *inode)
+ {
++ /* Disable it for ldiskfs, because going from a DX directory to
++ * a non-DX directory while it is in use will completely break
++ * the htree-locking.
++ * If we really want to support this operation in the future,
++ * we need to exclusively lock the directory at here which will
++ * increase complexity of code */
++#if 0
+ if (!EXT4_HAS_COMPAT_FEATURE(inode->i_sb,
+ EXT4_FEATURE_COMPAT_DIR_INDEX))
+ ext4_clear_inode_flag(inode, EXT4_INODE_INDEX);
++#endif
+ }
+
+ /*
+@@ -889,8 +1216,9 @@ static inline int search_dirblock(struct
+ * to brelse() it when appropriate.
+ */
+ struct buffer_head * ext4_find_entry(struct inode *dir,
+- const struct qstr *d_name,
+- struct ext4_dir_entry_2 ** res_dir)
++ const struct qstr *d_name,
++ struct ext4_dir_entry_2 **res_dir,
++ struct htree_lock *lck)
+ {
+ struct super_block *sb;
+ struct buffer_head *bh_use[NAMEI_RA_SIZE];
+@@ -911,7 +1239,7 @@ struct buffer_head * ext4_find_entry(str
+ if (namelen > EXT4_NAME_LEN)
+ return NULL;
+ if (is_dx(dir)) {
+- bh = ext4_dx_find_entry(dir, d_name, res_dir, &err);
++ bh = ext4_dx_find_entry(dir, d_name, res_dir, lck, &err);
+ /*
+ * On success, or if the error was file not found,
+ * return. Otherwise, fall back to doing a search the
+@@ -921,6 +1249,7 @@ struct buffer_head * ext4_find_entry(str
+ return bh;
+ dxtrace(printk(KERN_DEBUG "ext4_find_entry: dx failed, "
+ "falling back\n"));
++ ext4_htree_safe_relock(lck);
+ }
+ nblocks = dir->i_size >> EXT4_BLOCK_SIZE_BITS(sb);
+ start = EXT4_I(dir)->i_dir_start_lookup;
+@@ -998,13 +1327,15 @@ cleanup_and_exit:
+ }
+ EXPORT_SYMBOL(ext4_find_entry);
+
+-static struct buffer_head * ext4_dx_find_entry(struct inode *dir, const struct qstr *d_name,
+- struct ext4_dir_entry_2 **res_dir, int *err)
++static struct buffer_head * ext4_dx_find_entry(struct inode *dir,
++ const struct qstr *d_name,
++ struct ext4_dir_entry_2 **res_dir,
++ struct htree_lock *lck, int *err)
+ {
+ struct super_block * sb;
+ struct dx_hash_info hinfo;
+ u32 hash;
+- struct dx_frame frames[2], *frame;
++ struct dx_frame frames[EXT4_HTREE_LEVEL], *frame;
+ struct ext4_dir_entry_2 *de, *top;
+ struct buffer_head *bh;
+ ext4_lblk_t block;
+@@ -1015,13 +1346,16 @@ static struct buffer_head * ext4_dx_find
+ sb = dir->i_sb;
+ /* NFS may look up ".." - look at dx_root directory block */
+ if (namelen > 2 || name[0] != '.'||(name[1] != '.' && name[1] != '\0')){
+- if (!(frame = dx_probe(d_name, dir, &hinfo, frames, err)))
++ if (!(frame = dx_probe(d_name, dir, &hinfo, frames, lck, err)))
+ return NULL;
+ } else {
+ frame = frames;
+ frame->bh = NULL; /* for dx_release() */
+ frame->at = (struct dx_entry *)frames; /* hack for zero entry*/
+ dx_set_block(frame->at, 0); /* dx_root block is 0 */
++ /* "." and ".." are stored in root DX lock */
++ ext4_htree_dx_need_lock(lck);
++ ext4_htree_dx_lock(lck, NULL);
+ }
+ hash = hinfo.hash;
+ do {
+@@ -1050,7 +1384,7 @@ static struct buffer_head * ext4_dx_find
+ brelse(bh);
+ /* Check to see if we should continue to search */
+ retval = ext4_htree_next_block(dir, hash, frame,
+- frames, NULL);
++ frames, NULL, lck);
+ if (retval < 0) {
+ ext4_warning(sb,
+ "error reading index page in directory #%lu",
+@@ -1076,7 +1410,7 @@ static struct dentry *ext4_lookup(struct
+ if (dentry->d_name.len > EXT4_NAME_LEN)
+ return ERR_PTR(-ENAMETOOLONG);
+
+- bh = ext4_find_entry(dir, &dentry->d_name, &de);
++ bh = ext4_find_entry(dir, &dentry->d_name, &de, NULL);
+ inode = NULL;
+ if (bh) {
+ __u32 ino = le32_to_cpu(de->inode);
+@@ -1144,7 +1478,7 @@ struct dentry *ext4_get_parent(struct de
+ struct ext4_dir_entry_2 * de;
+ struct buffer_head *bh;
+
+- bh = ext4_find_entry(child->d_inode, &dotdot, &de);
++ bh = ext4_find_entry(child->d_inode, &dotdot, &de, NULL);
+ inode = NULL;
+ if (!bh)
+ return ERR_PTR(-ENOENT);
+@@ -1233,8 +1567,9 @@ static struct ext4_dir_entry_2* dx_pack_
+ * Returns pointer to de in block into which the new entry will be inserted.
+ */
+ static struct ext4_dir_entry_2 *do_split(handle_t *handle, struct inode *dir,
+- struct buffer_head **bh,struct dx_frame *frame,
+- struct dx_hash_info *hinfo, int *error)
++ struct buffer_head **bh, struct dx_frame *frames,
++ struct dx_frame *frame, struct dx_hash_info *hinfo,
++ struct htree_lock *lck, int *error)
+ {
+ unsigned blocksize = dir->i_sb->s_blocksize;
+ unsigned count, continued;
+@@ -1291,7 +1626,14 @@ static struct ext4_dir_entry_2 *do_split
+ hash2, split, count-split));
+
+ /* Fancy dance to stay within two buffers */
+- de2 = dx_move_dirents(data1, data2, map + split, count - split, blocksize);
++ if (hinfo->hash < hash2) {
++ de2 = dx_move_dirents(data1, data2, map + split,
++ count - split, blocksize);
++ } else {
++ /* make sure we will add entry to the same block which
++ * we have already locked */
++ de2 = dx_move_dirents(data1, data2, map, split, blocksize);
++ }
+ de = dx_pack_dirents(data1, blocksize);
+ de->rec_len = ext4_rec_len_to_disk(data1 + blocksize - (char *) de,
+ blocksize);
+@@ -1300,13 +1642,21 @@ static struct ext4_dir_entry_2 *do_split
+ dxtrace(dx_show_leaf (hinfo, (struct ext4_dir_entry_2 *) data1, blocksize, 1));
+ dxtrace(dx_show_leaf (hinfo, (struct ext4_dir_entry_2 *) data2, blocksize, 1));
+
+- /* Which block gets the new entry? */
+- if (hinfo->hash >= hash2)
+- {
+- swap(*bh, bh2);
+- de = de2;
++ ext4_htree_spin_lock(lck, frame > frames ? (frame - 1)->at : NULL,
++ frame->at); /* notify block is being split */
++ if (hinfo->hash < hash2) {
++ dx_insert_block(frame, hash2 + continued, newblock);
++
++ } else {
++ /* switch block number */
++ dx_insert_block(frame, hash2 + continued,
++ dx_get_block(frame->at));
++ dx_set_block(frame->at, newblock);
++ (frame->at)++;
+ }
+- dx_insert_block(frame, hash2 + continued, newblock);
++ ext4_htree_spin_unlock(lck);
++ ext4_htree_dx_unlock(lck);
++
+ err = ext4_handle_dirty_metadata(handle, dir, bh2);
+ if (err)
+ goto journal_error;
+@@ -1418,7 +1768,7 @@ static int add_dirent_to_buf(handle_t *h
+ if (!IS_NOCMTIME(dir))
+ dir->i_mtime = dir->i_ctime = ext4_current_time(dir);
+ ext4_update_dx_flag(dir);
+- dir->i_version++;
++ inode_inc_iversion(dir);
+ ext4_mark_inode_dirty(handle, dir);
+ BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
+ err = ext4_handle_dirty_metadata(handle, dir, bh);
+@@ -1438,7 +1788,7 @@ static int make_indexed_dir(handle_t *ha
+ const char *name = dentry->d_name.name;
+ int namelen = dentry->d_name.len;
+ struct buffer_head *bh2;
+- struct dx_frame frames[2], *frame;
++ struct dx_frame frames[EXT4_HTREE_LEVEL], *frame;
+ struct dx_entry *entries;
+ struct ext4_dir_entry_2 *de, *de2, *dot_de, *dotdot_de;
+ char *data1, *top;
+@@ -1517,7 +1867,7 @@ static int make_indexed_dir(handle_t *ha
+ frame->at = entries;
+ frame->bh = bh;
+ bh = bh2;
+- de = do_split(handle,dir, &bh, frame, &hinfo, &retval);
++ de = do_split(handle,dir, &bh, frames, frame, &hinfo, NULL, &retval);
+ dx_release (frames);
+ if (!(de))
+ return retval;
+@@ -1616,7 +1966,7 @@ out:
+ * the entry, as someone else might have used it while you slept.
+ */
+ int ext4_add_entry(handle_t *handle, struct dentry *dentry,
+- struct inode *inode)
++ struct inode *inode, struct htree_lock *lck)
+ {
+ struct inode *dir = dentry->d_parent->d_inode;
+ struct buffer_head *bh;
+@@ -1635,9 +1985,10 @@ int ext4_add_entry(handle_t *handle, str
+ if (dentry->d_name.len == 2 &&
+ memcmp(dentry->d_name.name, "..", 2) == 0)
+ return ext4_update_dotdot(handle, dentry, inode);
+- retval = ext4_dx_add_entry(handle, dentry, inode);
++ retval = ext4_dx_add_entry(handle, dentry, inode, lck);
+ if (!retval || (retval != ERR_BAD_DX_DIR))
+ return retval;
++ ext4_htree_safe_relock(lck);
+ ext4_clear_inode_flag(dir, EXT4_INODE_INDEX);
+ dx_fallback++;
+ ext4_mark_inode_dirty(handle, dir);
+@@ -1674,18 +2025,21 @@ EXPORT_SYMBOL(ext4_add_entry);
+ * Returns 0 for success, or a negative error value
+ */
+ static int ext4_dx_add_entry(handle_t *handle, struct dentry *dentry,
+- struct inode *inode)
++ struct inode *inode, struct htree_lock *lck)
+ {
+- struct dx_frame frames[2], *frame;
++ struct dx_frame frames[EXT4_HTREE_LEVEL], *frame;
+ struct dx_entry *entries, *at;
+ struct dx_hash_info hinfo;
+ struct buffer_head *bh;
+ struct inode *dir = dentry->d_parent->d_inode;
+ struct super_block *sb = dir->i_sb;
+ struct ext4_dir_entry_2 *de;
++ int restart;
+ int err;
+
+- frame = dx_probe(&dentry->d_name, dir, &hinfo, frames, &err);
++again:
++ restart = 0;
++ frame = dx_probe(&dentry->d_name, dir, &hinfo, frames, lck, &err);
+ if (!frame)
+ return err;
+ entries = frame->entries;
+@@ -1694,33 +2048,53 @@ static int ext4_dx_add_entry(handle_t *h
+ if (!(bh = ext4_bread(handle,dir, dx_get_block(frame->at), 0, &err)))
+ goto cleanup;
+
+- BUFFER_TRACE(bh, "get_write_access");
+- err = ext4_journal_get_write_access(handle, bh);
+- if (err)
+- goto journal_error;
+-
+ err = add_dirent_to_buf(handle, dentry, inode, NULL, bh);
+ if (err != -ENOSPC)
+ goto cleanup;
+
++ err = 0;
+ /* Block full, should compress but for now just split */
+ dxtrace(printk(KERN_DEBUG "using %u of %u node entries\n",
+ dx_get_count(entries), dx_get_limit(entries)));
+ /* Need to split index? */
+ if (dx_get_count(entries) == dx_get_limit(entries)) {
+ ext4_lblk_t newblock;
+- unsigned icount = dx_get_count(entries);
+- int levels = frame - frames;
++ int levels = frame - frames + 1;
++ unsigned icount;
++ int add_level = 1;
+ struct dx_entry *entries2;
+ struct dx_node *node2;
+ struct buffer_head *bh2;
+
+- if (levels && (dx_get_count(frames->entries) ==
+- dx_get_limit(frames->entries))) {
+- ext4_warning(sb, "Directory index full!");
++ if (!ext4_htree_safe_locked(lck)) { /* retry with EX lock */
++ ext4_htree_safe_relock(lck);
++ restart = 1;
++ goto cleanup;
++ }
++ while (frame > frames) {
++ if (dx_get_count((frame - 1)->entries) <
++ dx_get_limit((frame - 1)->entries)) {
++ add_level = 0;
++ break;
++ }
++ frame--; /* split higher index block */
++ at = frame->at;
++ entries = frame->entries;
++ restart = 1;
++ }
++ if (add_level && levels == ext4_dir_htree_level(sb)) {
++ ext4_warning(sb, "Directory (ino: %lu) index full, "
++ "reach max htree level :%d",
++ dir->i_ino, levels);
++ if (ext4_dir_htree_level(sb) < EXT4_HTREE_LEVEL) {
++ ext4_warning(sb, "Large directory feature is"
++ "not enabled on this "
++ "filesystem");
++ }
+ err = -ENOSPC;
+ goto cleanup;
+ }
++ icount = dx_get_count(entries);
+ bh2 = ext4_append (handle, dir, &newblock, &err);
+ if (!(bh2))
+ goto cleanup;
+@@ -1733,7 +2107,7 @@ static int ext4_dx_add_entry(handle_t *h
+ err = ext4_journal_get_write_access(handle, frame->bh);
+ if (err)
+ goto journal_error;
+- if (levels) {
++ if (!add_level) {
+ unsigned icount1 = icount/2, icount2 = icount - icount1;
+ unsigned hash2 = dx_get_hash(entries + icount1);
+ dxtrace(printk(KERN_DEBUG "Split index %i/%i\n",
+@@ -1741,7 +2115,7 @@ static int ext4_dx_add_entry(handle_t *h
+
+ BUFFER_TRACE(frame->bh, "get_write_access"); /* index root */
+ err = ext4_journal_get_write_access(handle,
+- frames[0].bh);
++ (frame - 1)->bh);
+ if (err)
+ goto journal_error;
+
+@@ -1757,18 +2131,24 @@ static int ext4_dx_add_entry(handle_t *h
+ frame->entries = entries = entries2;
+ swap(frame->bh, bh2);
+ }
+- dx_insert_block(frames + 0, hash2, newblock);
+- dxtrace(dx_show_index("node", frames[1].entries));
++ dx_insert_block((frame - 1), hash2, newblock);
++ dxtrace(dx_show_index("node", frame->entries));
+ dxtrace(dx_show_index("node",
+ ((struct dx_node *) bh2->b_data)->entries));
+ err = ext4_handle_dirty_metadata(handle, inode, bh2);
+ if (err)
+ goto journal_error;
+ brelse (bh2);
++ ext4_handle_dirty_metadata(handle, inode,
++ (frame - 1)->bh);
++ if (restart) {
++ ext4_handle_dirty_metadata(handle, inode,
++ frame->bh);
++ goto cleanup;
++ }
+ } else {
+ struct dx_root_info * info;
+- dxtrace(printk(KERN_DEBUG
+- "Creating second level index...\n"));
++
+ memcpy((char *) entries2, (char *) entries,
+ icount * sizeof(struct dx_entry));
+ dx_set_limit(entries2, dx_node_limit(dir));
+@@ -1778,32 +2158,60 @@ static int ext4_dx_add_entry(handle_t *h
+ dx_set_block(entries + 0, newblock);
+ info = dx_get_dx_info((struct ext4_dir_entry_2*)
+ frames[0].bh->b_data);
+- info->indirect_levels = 1;
++ info->indirect_levels += 1;
++ dxtrace(printk(KERN_DEBUG
++ "Creating %d level index...\n",
++ info->indirect_levels));
++ ext4_handle_dirty_metadata(handle, inode, frame->bh);
++ ext4_handle_dirty_metadata(handle, inode, bh2);
++ brelse(bh2);
++ restart = 1;
++ goto cleanup;
++ }
++ } else if (!ext4_htree_dx_locked(lck)) {
++ struct ext4_dir_lock_data *ld = ext4_htree_lock_data(lck);
+
+- /* Add new access path frame */
+- frame = frames + 1;
+- frame->at = at = at - entries + entries2;
+- frame->entries = entries = entries2;
+- frame->bh = bh2;
+- err = ext4_journal_get_write_access(handle,
+- frame->bh);
+- if (err)
+- goto journal_error;
++ /* not well protected, require DX lock */
++ ext4_htree_dx_need_lock(lck);
++ at = frame > frames ? (frame - 1)->at : NULL;
++
++ /* NB: no risk of deadlock because it's just a try.
++ *
++ * NB: we check ld_count for twice, the first time before
++ * having DX lock, the second time after holding DX lock.
++ *
++ * NB: We never free blocks for directory so far, which
++ * means value returned by dx_get_count() should equal to
++ * ld->ld_count if nobody split any DE-block under @at,
++ * and ld->ld_at still points to valid dx_entry. */
++ if ((ld->ld_count != dx_get_count(entries)) ||
++ !ext4_htree_dx_lock_try(lck, at) ||
++ (ld->ld_count != dx_get_count(entries))) {
++ restart = 1;
++ goto cleanup;
+ }
+- ext4_handle_dirty_metadata(handle, inode, frames[0].bh);
++ /* OK, I've got DX lock and nothing changed */
++ frame->at = ld->ld_at;
+ }
+- de = do_split(handle, dir, &bh, frame, &hinfo, &err);
++ de = do_split(handle, dir, &bh, frames, frame, &hinfo, lck, &err);
+ if (!de)
+ goto cleanup;
++
+ err = add_dirent_to_buf(handle, dentry, inode, de, bh);
+ goto cleanup;
+
+ journal_error:
+ ext4_std_error(dir->i_sb, err);
+ cleanup:
++ ext4_htree_dx_unlock(lck);
++ ext4_htree_de_unlock(lck);
+ if (bh)
+ brelse(bh);
+ dx_release(frames);
++ /* @restart is true means htree-path has been changed, we need to
++ * repeat dx_probe() to find out valid htree-path */
++ if (restart && err == 0)
++ goto again;
+ return err;
+ }
+
+@@ -1838,7 +2246,7 @@ int ext4_delete_entry(handle_t *handle,
+ blocksize);
+ else
+ de->inode = 0;
+- dir->i_version++;
++ inode_inc_iversion(dir);
+ BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
+ ext4_handle_dirty_metadata(handle, dir, bh);
+ return 0;
+@@ -1882,7 +2290,7 @@ static void ext4_dec_count(handle_t *han
+ static int ext4_add_nondir(handle_t *handle,
+ struct dentry *dentry, struct inode *inode)
+ {
+- int err = ext4_add_entry(handle, dentry, inode);
++ int err = ext4_add_entry(handle, dentry, inode, NULL);
+ if (!err) {
+ ext4_mark_inode_dirty(handle, inode);
+ d_instantiate(dentry, inode);
+@@ -2112,7 +2520,7 @@ retry:
+ goto out_stop;
+ }
+
+- err = ext4_add_entry(handle, dentry, inode);
++ err = ext4_add_entry(handle, dentry, inode, NULL);
+ if (err) {
+ clear_nlink(inode);
+ unlock_new_inode(inode);
+@@ -2381,7 +2789,7 @@ static int ext4_rmdir(struct inode *dir,
+ return PTR_ERR(handle);
+
+ retval = -ENOENT;
+- bh = ext4_find_entry(dir, &dentry->d_name, &de);
++ bh = ext4_find_entry(dir, &dentry->d_name, &de, NULL);
+ if (!bh)
+ goto end_rmdir;
+
+@@ -2443,7 +2851,7 @@ static int ext4_unlink(struct inode *dir
+ ext4_handle_sync(handle);
+
+ retval = -ENOENT;
+- bh = ext4_find_entry(dir, &dentry->d_name, &de);
++ bh = ext4_find_entry(dir, &dentry->d_name, &de, NULL);
+ if (!bh)
+ goto end_unlink;
+
+@@ -2567,7 +2975,7 @@ retry:
+ ext4_inc_count(handle, inode);
+ atomic_inc(&inode->i_count);
+
+- err = ext4_add_entry(handle, dentry, inode);
++ err = ext4_add_entry(handle, dentry, inode, NULL);
+ if (!err) {
+ ext4_mark_inode_dirty(handle, inode);
+ d_instantiate(dentry, inode);
+@@ -2612,7 +3020,7 @@ static int ext4_rename(struct inode *old
+ if (IS_DIRSYNC(old_dir) || IS_DIRSYNC(new_dir))
+ ext4_handle_sync(handle);
+
+- old_bh = ext4_find_entry(old_dir, &old_dentry->d_name, &old_de);
++ old_bh = ext4_find_entry(old_dir, &old_dentry->d_name, &old_de, NULL);
+ /*
+ * Check for inode number is _not_ due to possible IO errors.
+ * We might rmdir the source, keep it as pwd of some process
+@@ -2625,7 +3033,7 @@ static int ext4_rename(struct inode *old
+ goto end_rename;
+
+ new_inode = new_dentry->d_inode;
+- new_bh = ext4_find_entry(new_dir, &new_dentry->d_name, &new_de);
++ new_bh = ext4_find_entry(new_dir, &new_dentry->d_name, &new_de, NULL);
+ if (new_bh) {
+ if (!new_inode) {
+ brelse(new_bh);
+@@ -2651,7 +3059,7 @@ static int ext4_rename(struct inode *old
+ goto end_rename;
+ }
+ if (!new_bh) {
+- retval = ext4_add_entry(handle, new_dentry, old_inode);
++ retval = ext4_add_entry(handle, new_dentry, old_inode, NULL);
+ if (retval)
+ goto end_rename;
+ } else {
+@@ -2693,7 +3101,8 @@ static int ext4_rename(struct inode *old
+ struct buffer_head *old_bh2;
+ struct ext4_dir_entry_2 *old_de2;
+
+- old_bh2 = ext4_find_entry(old_dir, &old_dentry->d_name, &old_de2);
++ old_bh2 = ext4_find_entry(old_dir, &old_dentry->d_name,
++ &old_de2, NULL);
+ if (old_bh2) {
+ retval = ext4_delete_entry(handle, old_dir,
+ old_de2, old_bh2);
+--- linux-2.6.32-131.6.1/fs/ext4/inode.c 2011-10-06 20:10:49.000000000 +0800
++++ linux-2.6.32-131.6.1-pdo/fs/ext4/inode.c 2011-12-01 22:02:11.000000000 +0800
+@@ -5112,7 +5112,7 @@ struct inode *ext4_iget(struct super_blo
+ if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_64BIT))
+ ei->i_file_acl |=
+ ((__u64)le16_to_cpu(raw_inode->i_file_acl_high)) << 32;
+- inode->i_size = ext4_isize(raw_inode);
++ inode->i_size = ext4_isize(sb, raw_inode);
+ ei->i_disksize = inode->i_size;
+ #ifdef CONFIG_QUOTA
+ ei->i_reserved_quota = 0;
+--- linux-2.6.32-131.6.1/fs/ext4/Makefile 2011-10-06 20:10:49.000000000 +0800
++++ linux-2.6.32-131.6.1-pdo/fs/ext4/Makefile 2011-10-06 12:21:30.000000000 +0800
+@@ -7,7 +7,7 @@ obj-$(CONFIG_EXT4_FS) += ext4.o
+ ext4-y := balloc.o bitmap.o dir.o file.o fsync.o ialloc.o inode.o \
+ ioctl.o namei.o super.o symlink.o hash.o resize.o extents.o \
+ ext4_jbd2.o migrate.o mballoc.o block_validity.o move_extent.o \
+- mmp.o dynlocks.o
++ htree_lock.o mmp.o dynlocks.o
+
+ ext4-$(CONFIG_EXT4_FS_XATTR) += xattr.o xattr_user.o xattr_trusted.o
+ ext4-$(CONFIG_EXT4_FS_POSIX_ACL) += acl.o
git://git.whamcloud.com / fs / lustre-release.git / commitdiff