1 files changed, 337 insertions, 190 deletions

diff --git a/fs/inode.c b/fs/inode.c
index 86464332e590..ae2727ab0c3a 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -24,11 +24,11 @@
 #include <linux/mount.h>
 #include <linux/async.h>
 #include <linux/posix_acl.h>
+#include <linux/ima.h>
 
 /*
  * This is needed for the following functions:
  *  - inode_has_buffers
- *  - invalidate_inode_buffers
  *  - invalidate_bdev
  *
  * FIXME: remove all knowledge of the buffer layer from this file
@@ -72,8 +72,7 @@ static unsigned int i_hash_shift __read_mostly;
  * allowing for low-overhead inode sync() operations.
  */
 
-LIST_HEAD(inode_in_use);
-LIST_HEAD(inode_unused);
+static LIST_HEAD(inode_lru);
 static struct hlist_head *inode_hashtable __read_mostly;
 
 /*
@@ -103,8 +102,41 @@ static DECLARE_RWSEM(iprune_sem);
  */
 struct inodes_stat_t inodes_stat;
 
+static struct percpu_counter nr_inodes __cacheline_aligned_in_smp;
+static struct percpu_counter nr_inodes_unused __cacheline_aligned_in_smp;
+
 static struct kmem_cache *inode_cachep __read_mostly;
 
+static inline int get_nr_inodes(void)
+{
+        return percpu_counter_sum_positive(&nr_inodes);
+}
+
+static inline int get_nr_inodes_unused(void)
+{
+        return percpu_counter_sum_positive(&nr_inodes_unused);
+}
+
+int get_nr_dirty_inodes(void)
+{
+        int nr_dirty = get_nr_inodes() - get_nr_inodes_unused();
+        return nr_dirty > 0 ? nr_dirty : 0;
+
+}
+
+/*
+ * Handle nr_inode sysctl
+ */
+#ifdef CONFIG_SYSCTL
+int proc_nr_inodes(ctl_table *table, int write,
+                   void __user *buffer, size_t *lenp, loff_t *ppos)
+{
+        inodes_stat.nr_inodes = get_nr_inodes();
+        inodes_stat.nr_unused = get_nr_inodes_unused();
+        return proc_dointvec(table, write, buffer, lenp, ppos);
+}
+#endif
+
 static void wake_up_inode(struct inode *inode)
 {
         /*
@@ -192,6 +224,8 @@ int inode_init_always(struct super_block *sb, struct inode *inode)
         inode->i_fsnotify_mask = 0;
 #endif
 
+        percpu_counter_inc(&nr_inodes);
+
         return 0;
 out:
         return -ENOMEM;
@@ -232,11 +266,13 @@ void __destroy_inode(struct inode *inode)
         if (inode->i_default_acl && inode->i_default_acl != ACL_NOT_CACHED)
                 posix_acl_release(inode->i_default_acl);
 #endif
+        percpu_counter_dec(&nr_inodes);
 }
 EXPORT_SYMBOL(__destroy_inode);
 
-void destroy_inode(struct inode *inode)
+static void destroy_inode(struct inode *inode)
 {
+        BUG_ON(!list_empty(&inode->i_lru));
         __destroy_inode(inode);
         if (inode->i_sb->s_op->destroy_inode)
                 inode->i_sb->s_op->destroy_inode(inode);
@@ -255,6 +291,8 @@ void inode_init_once(struct inode *inode)
         INIT_HLIST_NODE(&inode->i_hash);
         INIT_LIST_HEAD(&inode->i_dentry);
         INIT_LIST_HEAD(&inode->i_devices);
+        INIT_LIST_HEAD(&inode->i_wb_list);
+        INIT_LIST_HEAD(&inode->i_lru);
         INIT_RADIX_TREE(&inode->i_data.page_tree, GFP_ATOMIC);
         spin_lock_init(&inode->i_data.tree_lock);
         spin_lock_init(&inode->i_data.i_mmap_lock);
@@ -281,14 +319,109 @@ static void init_once(void *foo)
  */
 void __iget(struct inode *inode)
 {
-        if (atomic_inc_return(&inode->i_count) != 1)
-                return;
+        atomic_inc(&inode->i_count);
+}
+
+/*
+ * get additional reference to inode; caller must already hold one.
+ */
+void ihold(struct inode *inode)
+{
+        WARN_ON(atomic_inc_return(&inode->i_count) < 2);
+}
+EXPORT_SYMBOL(ihold);
+
+static void inode_lru_list_add(struct inode *inode)
+{
+        if (list_empty(&inode->i_lru)) {
+                list_add(&inode->i_lru, &inode_lru);
+                percpu_counter_inc(&nr_inodes_unused);
+        }
+}
 
-        if (!(inode->i_state & (I_DIRTY|I_SYNC)))
-                list_move(&inode->i_list, &inode_in_use);
-        inodes_stat.nr_unused--;
+static void inode_lru_list_del(struct inode *inode)
+{
+        if (!list_empty(&inode->i_lru)) {
+                list_del_init(&inode->i_lru);
+                percpu_counter_dec(&nr_inodes_unused);
+        }
+}
+
+static inline void __inode_sb_list_add(struct inode *inode)
+{
+        list_add(&inode->i_sb_list, &inode->i_sb->s_inodes);
 }
 
+/**
+ * inode_sb_list_add - add inode to the superblock list of inodes
+ * @inode: inode to add
+ */
+void inode_sb_list_add(struct inode *inode)
+{
+        spin_lock(&inode_lock);
+        __inode_sb_list_add(inode);
+        spin_unlock(&inode_lock);
+}
+EXPORT_SYMBOL_GPL(inode_sb_list_add);
+
+static inline void __inode_sb_list_del(struct inode *inode)
+{
+        list_del_init(&inode->i_sb_list);
+}
+
+static unsigned long hash(struct super_block *sb, unsigned long hashval)
+{
+        unsigned long tmp;
+
+        tmp = (hashval * (unsigned long)sb) ^ (GOLDEN_RATIO_PRIME + hashval) /
+                        L1_CACHE_BYTES;
+        tmp = tmp ^ ((tmp ^ GOLDEN_RATIO_PRIME) >> I_HASHBITS);
+        return tmp & I_HASHMASK;
+}
+
+/**
+ *      __insert_inode_hash - hash an inode
+ *      @inode: unhashed inode
+ *      @hashval: unsigned long value used to locate this object in the
+ *              inode_hashtable.
+ *
+ *      Add an inode to the inode hash for this superblock.
+ */
+void __insert_inode_hash(struct inode *inode, unsigned long hashval)
+{
+        struct hlist_head *b = inode_hashtable + hash(inode->i_sb, hashval);
+
+        spin_lock(&inode_lock);
+        hlist_add_head(&inode->i_hash, b);
+        spin_unlock(&inode_lock);
+}
+EXPORT_SYMBOL(__insert_inode_hash);
+
+/**
+ *      __remove_inode_hash - remove an inode from the hash
+ *      @inode: inode to unhash
+ *
+ *      Remove an inode from the superblock.
+ */
+static void __remove_inode_hash(struct inode *inode)
+{
+        hlist_del_init(&inode->i_hash);
+}
+
+/**
+ *      remove_inode_hash - remove an inode from the hash
+ *      @inode: inode to unhash
+ *
+ *      Remove an inode from the superblock.
+ */
+void remove_inode_hash(struct inode *inode)
+{
+        spin_lock(&inode_lock);
+        hlist_del_init(&inode->i_hash);
+        spin_unlock(&inode_lock);
+}
+EXPORT_SYMBOL(remove_inode_hash);
+
 void end_writeback(struct inode *inode)
 {
         might_sleep();
@@ -327,101 +460,113 @@ static void evict(struct inode *inode)
  */
 static void dispose_list(struct list_head *head)
 {
-        int nr_disposed = 0;
-
         while (!list_empty(head)) {
                 struct inode *inode;
 
-                inode = list_first_entry(head, struct inode, i_list);
-                list_del(&inode->i_list);
+                inode = list_first_entry(head, struct inode, i_lru);
+                list_del_init(&inode->i_lru);
 
                 evict(inode);
 
                 spin_lock(&inode_lock);
-                hlist_del_init(&inode->i_hash);
-                list_del_init(&inode->i_sb_list);
+                __remove_inode_hash(inode);
+                __inode_sb_list_del(inode);
                 spin_unlock(&inode_lock);
 
                 wake_up_inode(inode);
                 destroy_inode(inode);
-                nr_disposed++;
         }
-        spin_lock(&inode_lock);
-        inodes_stat.nr_inodes -= nr_disposed;
-        spin_unlock(&inode_lock);
 }
 
-/*
- * Invalidate all inodes for a device.
+/**
+ * evict_inodes - evict all evictable inodes for a superblock
+ * @sb:         superblock to operate on
+ *
+ * Make sure that no inodes with zero refcount are retained.  This is
+ * called by superblock shutdown after having MS_ACTIVE flag removed,
+ * so any inode reaching zero refcount during or after that call will
+ * be immediately evicted.
  */
-static int invalidate_list(struct list_head *head, struct list_head *dispose)
+void evict_inodes(struct super_block *sb)
 {
-        struct list_head *next;
-        int busy = 0, count = 0;
-
-        next = head->next;
-        for (;;) {
-                struct list_head *tmp = next;
-                struct inode *inode;
+        struct inode *inode, *next;
+        LIST_HEAD(dispose);
 
-                /*
-                 * We can reschedule here without worrying about the list's
-                 * consistency because the per-sb list of inodes must not
-                 * change during umount anymore, and because iprune_sem keeps
-                 * shrink_icache_memory() away.
-                 */
-                cond_resched_lock(&inode_lock);
+        down_write(&iprune_sem);
 
-                next = next->next;
-                if (tmp == head)
-                        break;
-                inode = list_entry(tmp, struct inode, i_sb_list);
-                if (inode->i_state & I_NEW)
+        spin_lock(&inode_lock);
+        list_for_each_entry_safe(inode, next, &sb->s_inodes, i_sb_list) {
+                if (atomic_read(&inode->i_count))
                         continue;
-                invalidate_inode_buffers(inode);
-                if (!atomic_read(&inode->i_count)) {
-                        list_move(&inode->i_list, dispose);
-                        WARN_ON(inode->i_state & I_NEW);
-                        inode->i_state |= I_FREEING;
-                        count++;
+
+                if (inode->i_state & (I_NEW | I_FREEING | I_WILL_FREE)) {
+                        WARN_ON(1);
                         continue;
                 }
-                busy = 1;
+
+                inode->i_state |= I_FREEING;
+
+                /*
+                 * Move the inode off the IO lists and LRU once I_FREEING is
+                 * set so that it won't get moved back on there if it is dirty.
+                 */
+                list_move(&inode->i_lru, &dispose);
+                list_del_init(&inode->i_wb_list);
+                if (!(inode->i_state & (I_DIRTY | I_SYNC)))
+                        percpu_counter_dec(&nr_inodes_unused);
         }
-        /* only unused inodes may be cached with i_count zero */
-        inodes_stat.nr_unused -= count;
-        return busy;
+        spin_unlock(&inode_lock);
+
+        dispose_list(&dispose);
+        up_write(&iprune_sem);
 }
 
 /**
- *      invalidate_inodes       - discard the inodes on a device
- *      @sb: superblock
+ * invalidate_inodes    - attempt to free all inodes on a superblock
+ * @sb:         superblock to operate on
  *
- *      Discard all of the inodes for a given superblock. If the discard
- *      fails because there are busy inodes then a non zero value is returned.
- *      If the discard is successful all the inodes have been discarded.
+ * Attempts to free all inodes for a given superblock.  If there were any
+ * busy inodes return a non-zero value, else zero.
  */
 int invalidate_inodes(struct super_block *sb)
 {
-        int busy;
-        LIST_HEAD(throw_away);
+        int busy = 0;
+        struct inode *inode, *next;
+        LIST_HEAD(dispose);
 
         down_write(&iprune_sem);
+
         spin_lock(&inode_lock);
-        fsnotify_unmount_inodes(&sb->s_inodes);
-        busy = invalidate_list(&sb->s_inodes, &throw_away);
+        list_for_each_entry_safe(inode, next, &sb->s_inodes, i_sb_list) {
+                if (inode->i_state & (I_NEW | I_FREEING | I_WILL_FREE))
+                        continue;
+                if (atomic_read(&inode->i_count)) {
+                        busy = 1;
+                        continue;
+                }
+
+                inode->i_state |= I_FREEING;
+
+                /*
+                 * Move the inode off the IO lists and LRU once I_FREEING is
+                 * set so that it won't get moved back on there if it is dirty.
+                 */
+                list_move(&inode->i_lru, &dispose);
+                list_del_init(&inode->i_wb_list);
+                if (!(inode->i_state & (I_DIRTY | I_SYNC)))
+                        percpu_counter_dec(&nr_inodes_unused);
+        }
         spin_unlock(&inode_lock);
 
-        dispose_list(&throw_away);
+        dispose_list(&dispose);
         up_write(&iprune_sem);
 
         return busy;
 }
-EXPORT_SYMBOL(invalidate_inodes);
 
 static int can_unuse(struct inode *inode)
 {
-        if (inode->i_state)
+        if (inode->i_state & ~I_REFERENCED)
                 return 0;
         if (inode_has_buffers(inode))
                 return 0;
@@ -433,22 +578,24 @@ static int can_unuse(struct inode *inode)
 }
 
 /*
- * Scan `goal' inodes on the unused list for freeable ones. They are moved to
- * a temporary list and then are freed outside inode_lock by dispose_list().
+ * Scan `goal' inodes on the unused list for freeable ones. They are moved to a
+ * temporary list and then are freed outside inode_lock by dispose_list().
  *
  * Any inodes which are pinned purely because of attached pagecache have their
- * pagecache removed.  We expect the final iput() on that inode to add it to
- * the front of the inode_unused list.  So look for it there and if the
- * inode is still freeable, proceed.  The right inode is found 99.9% of the
- * time in testing on a 4-way.
+ * pagecache removed.  If the inode has metadata buffers attached to
+ * mapping->private_list then try to remove them.
  *
- * If the inode has metadata buffers attached to mapping->private_list then
- * try to remove them.
+ * If the inode has the I_REFERENCED flag set, then it means that it has been
+ * used recently - the flag is set in iput_final(). When we encounter such an
+ * inode, clear the flag and move it to the back of the LRU so it gets another
+ * pass through the LRU before it gets reclaimed. This is necessary because of
+ * the fact we are doing lazy LRU updates to minimise lock contention so the
+ * LRU does not have strict ordering. Hence we don't want to reclaim inodes
+ * with this flag set because they are the inodes that are out of order.
  */
 static void prune_icache(int nr_to_scan)
 {
         LIST_HEAD(freeable);
-        int nr_pruned = 0;
         int nr_scanned;
         unsigned long reap = 0;
 
@@ -457,13 +604,26 @@ static void prune_icache(int nr_to_scan)
         for (nr_scanned = 0; nr_scanned < nr_to_scan; nr_scanned++) {
                 struct inode *inode;
 
-                if (list_empty(&inode_unused))
+                if (list_empty(&inode_lru))
                         break;
 
-                inode = list_entry(inode_unused.prev, struct inode, i_list);
+                inode = list_entry(inode_lru.prev, struct inode, i_lru);
 
-                if (inode->i_state || atomic_read(&inode->i_count)) {
-                        list_move(&inode->i_list, &inode_unused);
+                /*
+                 * Referenced or dirty inodes are still in use. Give them
+                 * another pass through the LRU as we canot reclaim them now.
+                 */
+                if (atomic_read(&inode->i_count) ||
+                    (inode->i_state & ~I_REFERENCED)) {
+                        list_del_init(&inode->i_lru);
+                        percpu_counter_dec(&nr_inodes_unused);
+                        continue;
+                }
+
+                /* recently referenced inodes get one more pass */
+                if (inode->i_state & I_REFERENCED) {
+                        list_move(&inode->i_lru, &inode_lru);
+                        inode->i_state &= ~I_REFERENCED;
                         continue;
                 }
                 if (inode_has_buffers(inode) || inode->i_data.nrpages) {
@@ -475,18 +635,23 @@ static void prune_icache(int nr_to_scan)
                         iput(inode);
                         spin_lock(&inode_lock);
 
-                        if (inode != list_entry(inode_unused.next,
-                                                struct inode, i_list))
+                        if (inode != list_entry(inode_lru.next,
+                                                struct inode, i_lru))
                                 continue;       /* wrong inode or list_empty */
                         if (!can_unuse(inode))
                                 continue;
                 }
-                list_move(&inode->i_list, &freeable);
                 WARN_ON(inode->i_state & I_NEW);
                 inode->i_state |= I_FREEING;
-                nr_pruned++;
+
+                /*
+                 * Move the inode off the IO lists and LRU once I_FREEING is
+                 * set so that it won't get moved back on there if it is dirty.
+                 */
+                list_move(&inode->i_lru, &freeable);
+                list_del_init(&inode->i_wb_list);
+                percpu_counter_dec(&nr_inodes_unused);
         }
-        inodes_stat.nr_unused -= nr_pruned;
         if (current_is_kswapd())
                 __count_vm_events(KSWAPD_INODESTEAL, reap);
         else
@@ -518,7 +683,7 @@ static int shrink_icache_memory(struct shrinker *shrink, int nr, gfp_t gfp_mask)
                         return -1;
                 prune_icache(nr);
         }
-        return (inodes_stat.nr_unused / 100) * sysctl_vfs_cache_pressure;
+        return (get_nr_inodes_unused() / 100) * sysctl_vfs_cache_pressure;
 }
 
 static struct shrinker icache_shrinker = {
@@ -529,9 +694,6 @@ static struct shrinker icache_shrinker = {
 static void __wait_on_freeing_inode(struct inode *inode);
 /*
  * Called with the inode lock held.
- * NOTE: we are not increasing the inode-refcount, you must call __iget()
- * by hand after calling find_inode now! This simplifies iunique and won't
- * add any additional branch in the common code.
  */
 static struct inode *find_inode(struct super_block *sb,
                                 struct hlist_head *head,
@@ -551,9 +713,10 @@ repeat:
                         __wait_on_freeing_inode(inode);
                         goto repeat;
                 }
-                break;
+                __iget(inode);
+                return inode;
         }
-        return node ? inode : NULL;
+        return NULL;
 }
 
 /*
@@ -576,53 +739,49 @@ repeat:
                         __wait_on_freeing_inode(inode);
                         goto repeat;
                 }
-                break;
+                __iget(inode);
+                return inode;
         }
-        return node ? inode : NULL;
-}
-
-static unsigned long hash(struct super_block *sb, unsigned long hashval)
-{
-        unsigned long tmp;
-
-        tmp = (hashval * (unsigned long)sb) ^ (GOLDEN_RATIO_PRIME + hashval) /
-                        L1_CACHE_BYTES;
-        tmp = tmp ^ ((tmp ^ GOLDEN_RATIO_PRIME) >> I_HASHBITS);
-        return tmp & I_HASHMASK;
-}
-
-static inline void
-__inode_add_to_lists(struct super_block *sb, struct hlist_head *head,
-                        struct inode *inode)
-{
-        inodes_stat.nr_inodes++;
-        list_add(&inode->i_list, &inode_in_use);
-        list_add(&inode->i_sb_list, &sb->s_inodes);
-        if (head)
-                hlist_add_head(&inode->i_hash, head);
+        return NULL;
 }
 
-/**
- * inode_add_to_lists - add a new inode to relevant lists
- * @sb: superblock inode belongs to
- * @inode: inode to mark in use
+/*
+ * Each cpu owns a range of LAST_INO_BATCH numbers.
+ * 'shared_last_ino' is dirtied only once out of LAST_INO_BATCH allocations,
+ * to renew the exhausted range.
  *
- * When an inode is allocated it needs to be accounted for, added to the in use
- * list, the owning superblock and the inode hash. This needs to be done under
- * the inode_lock, so export a function to do this rather than the inode lock
- * itself. We calculate the hash list to add to here so it is all internal
- * which requires the caller to have already set up the inode number in the
- * inode to add.
+ * This does not significantly increase overflow rate because every CPU can
+ * consume at most LAST_INO_BATCH-1 unused inode numbers. So there is
+ * NR_CPUS*(LAST_INO_BATCH-1) wastage. At 4096 and 1024, this is ~0.1% of the
+ * 2^32 range, and is a worst-case. Even a 50% wastage would only increase
+ * overflow rate by 2x, which does not seem too significant.
+ *
+ * On a 32bit, non LFS stat() call, glibc will generate an EOVERFLOW
+ * error if st_ino won't fit in target struct field. Use 32bit counter
+ * here to attempt to avoid that.
  */
-void inode_add_to_lists(struct super_block *sb, struct inode *inode)
+#define LAST_INO_BATCH 1024
+static DEFINE_PER_CPU(unsigned int, last_ino);
+
+unsigned int get_next_ino(void)
 {
-        struct hlist_head *head = inode_hashtable + hash(sb, inode->i_ino);
+        unsigned int *p = &get_cpu_var(last_ino);
+        unsigned int res = *p;
 
-        spin_lock(&inode_lock);
-        __inode_add_to_lists(sb, head, inode);
-        spin_unlock(&inode_lock);
+#ifdef CONFIG_SMP
+        if (unlikely((res & (LAST_INO_BATCH-1)) == 0)) {
+                static atomic_t shared_last_ino;
+                int next = atomic_add_return(LAST_INO_BATCH, &shared_last_ino);
+
+                res = next - LAST_INO_BATCH;
+        }
+#endif
+
+        *p = ++res;
+        put_cpu_var(last_ino);
+        return res;
 }
-EXPORT_SYMBOL_GPL(inode_add_to_lists);
+EXPORT_SYMBOL(get_next_ino);
 
 /**
  *      new_inode       - obtain an inode
@@ -638,12 +797,6 @@ EXPORT_SYMBOL_GPL(inode_add_to_lists);
  */
 struct inode *new_inode(struct super_block *sb)
 {
-        /*
-         * On a 32bit, non LFS stat() call, glibc will generate an EOVERFLOW
-         * error if st_ino won't fit in target struct field. Use 32bit counter
-         * here to attempt to avoid that.
-         */
-        static unsigned int last_ino;
         struct inode *inode;
 
         spin_lock_prefetch(&inode_lock);
@@ -651,8 +804,7 @@ struct inode *new_inode(struct super_block *sb)
         inode = alloc_inode(sb);
         if (inode) {
                 spin_lock(&inode_lock);
-                __inode_add_to_lists(sb, NULL, inode);
-                inode->i_ino = ++last_ino;
+                __inode_sb_list_add(inode);
                 inode->i_state = 0;
                 spin_unlock(&inode_lock);
         }
@@ -663,7 +815,7 @@ EXPORT_SYMBOL(new_inode);
 void unlock_new_inode(struct inode *inode)
 {
 #ifdef CONFIG_DEBUG_LOCK_ALLOC
-        if (inode->i_mode & S_IFDIR) {
+        if (S_ISDIR(inode->i_mode)) {
                 struct file_system_type *type = inode->i_sb->s_type;
 
                 /* Set new key only if filesystem hasn't already changed it */
@@ -720,7 +872,8 @@ static struct inode *get_new_inode(struct super_block *sb,
                         if (set(inode, data))
                                 goto set_failed;
 
-                        __inode_add_to_lists(sb, head, inode);
+                        hlist_add_head(&inode->i_hash, head);
+                        __inode_sb_list_add(inode);
                         inode->i_state = I_NEW;
                         spin_unlock(&inode_lock);
 
@@ -735,7 +888,6 @@ static struct inode *get_new_inode(struct super_block *sb,
                  * us. Use the old inode instead of the one we just
                  * allocated.
                  */
-                __iget(old);
                 spin_unlock(&inode_lock);
                 destroy_inode(inode);
                 inode = old;
@@ -767,7 +919,8 @@ static struct inode *get_new_inode_fast(struct super_block *sb,
                 old = find_inode_fast(sb, head, ino);
                 if (!old) {
                         inode->i_ino = ino;
-                        __inode_add_to_lists(sb, head, inode);
+                        hlist_add_head(&inode->i_hash, head);
+                        __inode_sb_list_add(inode);
                         inode->i_state = I_NEW;
                         spin_unlock(&inode_lock);
 
@@ -782,7 +935,6 @@ static struct inode *get_new_inode_fast(struct super_block *sb,
                  * us. Use the old inode instead of the one we just
                  * allocated.
                  */
-                __iget(old);
                 spin_unlock(&inode_lock);
                 destroy_inode(inode);
                 inode = old;
@@ -791,6 +943,27 @@ static struct inode *get_new_inode_fast(struct super_block *sb,
         return inode;
 }
 
+/*
+ * search the inode cache for a matching inode number.
+ * If we find one, then the inode number we are trying to
+ * allocate is not unique and so we should not use it.
+ *
+ * Returns 1 if the inode number is unique, 0 if it is not.
+ */
+static int test_inode_iunique(struct super_block *sb, unsigned long ino)
+{
+        struct hlist_head *b = inode_hashtable + hash(sb, ino);
+        struct hlist_node *node;
+        struct inode *inode;
+
+        hlist_for_each_entry(inode, node, b, i_hash) {
+                if (inode->i_ino == ino && inode->i_sb == sb)
+                        return 0;
+        }
+
+        return 1;
+}
+
 /**
  *      iunique - get a unique inode number
  *      @sb: superblock
@@ -812,19 +985,18 @@ ino_t iunique(struct super_block *sb, ino_t max_reserved)
          * error if st_ino won't fit in target struct field. Use 32bit counter
          * here to attempt to avoid that.
          */
+        static DEFINE_SPINLOCK(iunique_lock);
         static unsigned int counter;
-        struct inode *inode;
-        struct hlist_head *head;
         ino_t res;
 
         spin_lock(&inode_lock);
+        spin_lock(&iunique_lock);
         do {
                 if (counter <= max_reserved)
                         counter = max_reserved + 1;
                 res = counter++;
-                head = inode_hashtable + hash(sb, res);
-                inode = find_inode_fast(sb, head, res);
-        } while (inode != NULL);
+        } while (!test_inode_iunique(sb, res));
+        spin_unlock(&iunique_lock);
         spin_unlock(&inode_lock);
 
         return res;
@@ -876,7 +1048,6 @@ static struct inode *ifind(struct super_block *sb,
         spin_lock(&inode_lock);
         inode = find_inode(sb, head, test, data);
         if (inode) {
-                __iget(inode);
                 spin_unlock(&inode_lock);
                 if (likely(wait))
                         wait_on_inode(inode);
@@ -909,7 +1080,6 @@ static struct inode *ifind_fast(struct super_block *sb,
         spin_lock(&inode_lock);
         inode = find_inode_fast(sb, head, ino);
         if (inode) {
-                __iget(inode);
                 spin_unlock(&inode_lock);
                 wait_on_inode(inode);
                 return inode;
@@ -1095,7 +1265,7 @@ int insert_inode_locked(struct inode *inode)
                 __iget(old);
                 spin_unlock(&inode_lock);
                 wait_on_inode(old);
-                if (unlikely(!hlist_unhashed(&old->i_hash))) {
+                if (unlikely(!inode_unhashed(old))) {
                         iput(old);
                         return -EBUSY;
                 }
@@ -1134,7 +1304,7 @@ int insert_inode_locked4(struct inode *inode, unsigned long hashval,
                 __iget(old);
                 spin_unlock(&inode_lock);
                 wait_on_inode(old);
-                if (unlikely(!hlist_unhashed(&old->i_hash))) {
+                if (unlikely(!inode_unhashed(old))) {
                         iput(old);
                         return -EBUSY;
                 }
@@ -1143,36 +1313,6 @@ int insert_inode_locked4(struct inode *inode, unsigned long hashval,
 }
 EXPORT_SYMBOL(insert_inode_locked4);
 
-/**
- *      __insert_inode_hash - hash an inode
- *      @inode: unhashed inode
- *      @hashval: unsigned long value used to locate this object in the
- *              inode_hashtable.
- *
- *      Add an inode to the inode hash for this superblock.
- */
-void __insert_inode_hash(struct inode *inode, unsigned long hashval)
-{
-        struct hlist_head *head = inode_hashtable + hash(inode->i_sb, hashval);
-        spin_lock(&inode_lock);
-        hlist_add_head(&inode->i_hash, head);
-        spin_unlock(&inode_lock);
-}
-EXPORT_SYMBOL(__insert_inode_hash);
-
-/**
- *      remove_inode_hash - remove an inode from the hash
- *      @inode: inode to unhash
- *
- *      Remove an inode from the superblock.
- */
-void remove_inode_hash(struct inode *inode)
-{
-        spin_lock(&inode_lock);
-        hlist_del_init(&inode->i_hash);
-        spin_unlock(&inode_lock);
-}
-EXPORT_SYMBOL(remove_inode_hash);
 
 int generic_delete_inode(struct inode *inode)
 {
@@ -1187,7 +1327,7 @@ EXPORT_SYMBOL(generic_delete_inode);
  */
 int generic_drop_inode(struct inode *inode)
 {
-        return !inode->i_nlink || hlist_unhashed(&inode->i_hash);
+        return !inode->i_nlink || inode_unhashed(inode);
 }
 EXPORT_SYMBOL_GPL(generic_drop_inode);
 
@@ -1213,10 +1353,11 @@ static void iput_final(struct inode *inode)
                 drop = generic_drop_inode(inode);
 
         if (!drop) {
-                if (!(inode->i_state & (I_DIRTY|I_SYNC)))
-                        list_move(&inode->i_list, &inode_unused);
-                inodes_stat.nr_unused++;
                 if (sb->s_flags & MS_ACTIVE) {
+                        inode->i_state |= I_REFERENCED;
+                        if (!(inode->i_state & (I_DIRTY|I_SYNC))) {
+                                inode_lru_list_add(inode);
+                        }
                         spin_unlock(&inode_lock);
                         return;
                 }
@@ -1227,19 +1368,23 @@ static void iput_final(struct inode *inode)
                 spin_lock(&inode_lock);
                 WARN_ON(inode->i_state & I_NEW);
                 inode->i_state &= ~I_WILL_FREE;
-                inodes_stat.nr_unused--;
-                hlist_del_init(&inode->i_hash);
+                __remove_inode_hash(inode);
         }
-        list_del_init(&inode->i_list);
-        list_del_init(&inode->i_sb_list);
+
         WARN_ON(inode->i_state & I_NEW);
         inode->i_state |= I_FREEING;
-        inodes_stat.nr_inodes--;
+
+        /*
+         * Move the inode off the IO lists and LRU once I_FREEING is
+         * set so that it won't get moved back on there if it is dirty.
+         */
+        inode_lru_list_del(inode);
+        list_del_init(&inode->i_wb_list);
+
+        __inode_sb_list_del(inode);
         spin_unlock(&inode_lock);
         evict(inode);
-        spin_lock(&inode_lock);
-        hlist_del_init(&inode->i_hash);
-        spin_unlock(&inode_lock);
+        remove_inode_hash(inode);
         wake_up_inode(inode);
         BUG_ON(inode->i_state != (I_FREEING | I_CLEAR));
         destroy_inode(inode);
@@ -1503,6 +1648,8 @@ void __init inode_init(void)
                                          SLAB_MEM_SPREAD),
                                          init_once);
         register_shrinker(&icache_shrinker);
+        percpu_counter_init(&nr_inodes, 0);
+        percpu_counter_init(&nr_inodes_unused, 0);
 
         /* Hash may have been set up in inode_init_early */
         if (!hashdist)