fs: protect inode->i_state with inode->i_lock

Protect inode state transitions and validity checks with the
inode->i_lock. This enables us to make inode state transitions
independently of the inode_lock and is the first step to peeling
away the inode_lock from the code.

This requires that __iget() is done atomically with i_state checks
during list traversals so that we don't race with another thread
marking the inode I_FREEING between the state check and grabbing the
reference.

Also remove the unlock_new_inode() memory barrier optimisation
required to avoid taking the inode_lock when clearing I_NEW.
Simplify the code by simply taking the inode->i_lock around the
state change and wakeup. Because the wakeup is no longer tricky,
remove the wake_up_inode() function and open code the wakeup where
necessary.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

11 files changed, 174 insertions, 74 deletions

diff --git a/fs/block_dev.c b/fs/block_dev.c
index 889287019599..bc39b18cf3d0 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -56,9 +56,11 @@ static void bdev_inode_switch_bdi(struct inode *inode,
                         struct backing_dev_info *dst)
 {
         spin_lock(&inode_lock);
+        spin_lock(&inode->i_lock);
         inode->i_data.backing_dev_info = dst;
         if (inode->i_state & I_DIRTY)
                 list_move(&inode->i_wb_list, &dst->wb.b_dirty);
+        spin_unlock(&inode->i_lock);
         spin_unlock(&inode_lock);
 }
 
diff --git a/fs/buffer.c b/fs/buffer.c
index 2219a76e2caf..da666f3148f9 100644
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -1144,7 +1144,7 @@ __getblk_slow(struct block_device *bdev, sector_t block, int size)
  * inode list.
  *
  * mark_buffer_dirty() is atomic.  It takes bh->b_page->mapping->private_lock,
- * mapping->tree_lock and the global inode_lock.
+ * mapping->tree_lock and mapping->host->i_lock.
  */
 void mark_buffer_dirty(struct buffer_head *bh)
 {
diff --git a/fs/drop_caches.c b/fs/drop_caches.c
index 816f88e6b9ce..6c6f73ba0868 100644
--- a/fs/drop_caches.c
+++ b/fs/drop_caches.c
@@ -18,11 +18,14 @@ static void drop_pagecache_sb(struct super_block *sb, void *unused)
 
         spin_lock(&inode_lock);
         list_for_each_entry(inode, &sb->s_inodes, i_sb_list) {
-                if (inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW))
-                        continue;
-                if (inode->i_mapping->nrpages == 0)
+                spin_lock(&inode->i_lock);
+                if ((inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW)) ||
+                    (inode->i_mapping->nrpages == 0)) {
+                        spin_unlock(&inode->i_lock);
                         continue;
+                }
                 __iget(inode);
+                spin_unlock(&inode->i_lock);
                 spin_unlock(&inode_lock);
                 invalidate_mapping_pages(inode->i_mapping, 0, -1);
                 iput(toput_inode);
diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index 59c6e4956786..efd1ebe879cc 100644
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -306,10 +306,12 @@ static void inode_wait_for_writeback(struct inode *inode)
         wait_queue_head_t *wqh;
 
         wqh = bit_waitqueue(&inode->i_state, __I_SYNC);
-         while (inode->i_state & I_SYNC) {
+        while (inode->i_state & I_SYNC) {
+                spin_unlock(&inode->i_lock);
                 spin_unlock(&inode_lock);
                 __wait_on_bit(wqh, &wq, inode_wait, TASK_UNINTERRUPTIBLE);
                 spin_lock(&inode_lock);
+                spin_lock(&inode->i_lock);
         }
 }
 
@@ -333,6 +335,7 @@ writeback_single_inode(struct inode *inode, struct writeback_control *wbc)
         unsigned dirty;
         int ret;
 
+        spin_lock(&inode->i_lock);
         if (!atomic_read(&inode->i_count))
                 WARN_ON(!(inode->i_state & (I_WILL_FREE|I_FREEING)));
         else
@@ -348,6 +351,7 @@ writeback_single_inode(struct inode *inode, struct writeback_control *wbc)
                  * completed a full scan of b_io.
                  */
                 if (wbc->sync_mode != WB_SYNC_ALL) {
+                        spin_unlock(&inode->i_lock);
                         requeue_io(inode);
                         return 0;
                 }
@@ -363,6 +367,7 @@ writeback_single_inode(struct inode *inode, struct writeback_control *wbc)
         /* Set I_SYNC, reset I_DIRTY_PAGES */
         inode->i_state |= I_SYNC;
         inode->i_state &= ~I_DIRTY_PAGES;
+        spin_unlock(&inode->i_lock);
         spin_unlock(&inode_lock);
 
         ret = do_writepages(mapping, wbc);
@@ -384,8 +389,10 @@ writeback_single_inode(struct inode *inode, struct writeback_control *wbc)
          * write_inode()
          */
         spin_lock(&inode_lock);
+        spin_lock(&inode->i_lock);
         dirty = inode->i_state & I_DIRTY;
         inode->i_state &= ~(I_DIRTY_SYNC | I_DIRTY_DATASYNC);
+        spin_unlock(&inode->i_lock);
         spin_unlock(&inode_lock);
         /* Don't write the inode if only I_DIRTY_PAGES was set */
         if (dirty & (I_DIRTY_SYNC | I_DIRTY_DATASYNC)) {
@@ -395,6 +402,7 @@ writeback_single_inode(struct inode *inode, struct writeback_control *wbc)
         }
 
         spin_lock(&inode_lock);
+        spin_lock(&inode->i_lock);
         inode->i_state &= ~I_SYNC;
         if (!(inode->i_state & I_FREEING)) {
                 if (mapping_tagged(mapping, PAGECACHE_TAG_DIRTY)) {
@@ -436,6 +444,7 @@ writeback_single_inode(struct inode *inode, struct writeback_control *wbc)
                 }
         }
         inode_sync_complete(inode);
+        spin_unlock(&inode->i_lock);
         return ret;
 }
 
@@ -506,7 +515,9 @@ static int writeback_sb_inodes(struct super_block *sb, struct bdi_writeback *wb,
                  * kind does not need peridic writeout yet, and for the latter
                  * kind writeout is handled by the freer.
                  */
+                spin_lock(&inode->i_lock);
                 if (inode->i_state & (I_NEW | I_FREEING | I_WILL_FREE)) {
+                        spin_unlock(&inode->i_lock);
                         requeue_io(inode);
                         continue;
                 }
@@ -515,10 +526,14 @@ static int writeback_sb_inodes(struct super_block *sb, struct bdi_writeback *wb,
                  * Was this inode dirtied after sync_sb_inodes was called?
                  * This keeps sync from extra jobs and livelock.
                  */
-                if (inode_dirtied_after(inode, wbc->wb_start))
+                if (inode_dirtied_after(inode, wbc->wb_start)) {
+                        spin_unlock(&inode->i_lock);
                         return 1;
+                }
 
                 __iget(inode);
+                spin_unlock(&inode->i_lock);
+
                 pages_skipped = wbc->pages_skipped;
                 writeback_single_inode(inode, wbc);
                 if (wbc->pages_skipped != pages_skipped) {
@@ -724,7 +739,9 @@ static long wb_writeback(struct bdi_writeback *wb,
                 if (!list_empty(&wb->b_more_io))  {
                         inode = wb_inode(wb->b_more_io.prev);
                         trace_wbc_writeback_wait(&wbc, wb->bdi);
+                        spin_lock(&inode->i_lock);
                         inode_wait_for_writeback(inode);
+                        spin_unlock(&inode->i_lock);
                 }
                 spin_unlock(&inode_lock);
         }
@@ -1017,6 +1034,7 @@ void __mark_inode_dirty(struct inode *inode, int flags)
                 block_dump___mark_inode_dirty(inode);
 
         spin_lock(&inode_lock);
+        spin_lock(&inode->i_lock);
         if ((inode->i_state & flags) != flags) {
                 const int was_dirty = inode->i_state & I_DIRTY;
 
@@ -1028,7 +1046,7 @@ void __mark_inode_dirty(struct inode *inode, int flags)
                  * superblock list, based upon its state.
                  */
                 if (inode->i_state & I_SYNC)
-                        goto out;
+                        goto out_unlock_inode;
 
                 /*
                  * Only add valid (hashed) inodes to the superblock's
@@ -1036,11 +1054,12 @@ void __mark_inode_dirty(struct inode *inode, int flags)
                  */
                 if (!S_ISBLK(inode->i_mode)) {
                         if (inode_unhashed(inode))
-                                goto out;
+                                goto out_unlock_inode;
                 }
                 if (inode->i_state & I_FREEING)
-                        goto out;
+                        goto out_unlock_inode;
 
+                spin_unlock(&inode->i_lock);
                 /*
                  * If the inode was already on b_dirty/b_io/b_more_io, don't
                  * reposition it (that would break b_dirty time-ordering).
@@ -1065,7 +1084,10 @@ void __mark_inode_dirty(struct inode *inode, int flags)
                         inode->dirtied_when = jiffies;
                         list_move(&inode->i_wb_list, &bdi->wb.b_dirty);
                 }
+                goto out;
         }
+out_unlock_inode:
+        spin_unlock(&inode->i_lock);
 out:
         spin_unlock(&inode_lock);
 
@@ -1111,14 +1133,16 @@ static void wait_sb_inodes(struct super_block *sb)
          * we still have to wait for that writeout.
          */
         list_for_each_entry(inode, &sb->s_inodes, i_sb_list) {
-                struct address_space *mapping;
+                struct address_space *mapping = inode->i_mapping;
 
-                if (inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW))
-                        continue;
-                mapping = inode->i_mapping;
-                if (mapping->nrpages == 0)
+                spin_lock(&inode->i_lock);
+                if ((inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW)) ||
+                    (mapping->nrpages == 0)) {
+                        spin_unlock(&inode->i_lock);
                         continue;
+                }
                 __iget(inode);
+                spin_unlock(&inode->i_lock);
                 spin_unlock(&inode_lock);
                 /*
                  * We hold a reference to 'inode' so it couldn't have
diff --git a/fs/inode.c b/fs/inode.c
index 0b3da4a77704..14b12c4ee026 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -28,6 +28,17 @@
 #include <linux/cred.h>
 
 /*
+ * inode locking rules.
+ *
+ * inode->i_lock protects:
+ *   inode->i_state, inode->i_hash, __iget()
+ *
+ * Lock ordering:
+ * inode_lock
+ *   inode->i_lock
+ */
+
+/*
  * This is needed for the following functions:
  *  - inode_has_buffers
  *  - invalidate_bdev
@@ -137,15 +148,6 @@ int proc_nr_inodes(ctl_table *table, int write,
 }
 #endif
 
-static void wake_up_inode(struct inode *inode)
-{
-        /*
-         * Prevent speculative execution through spin_unlock(&inode_lock);
-         */
-        smp_mb();
-        wake_up_bit(&inode->i_state, __I_NEW);
-}
-
 /**
  * inode_init_always - perform inode structure intialisation
  * @sb: superblock inode belongs to
@@ -336,7 +338,7 @@ static void init_once(void *foo)
 }
 
 /*
- * inode_lock must be held
+ * inode->i_lock must be held
  */
 void __iget(struct inode *inode)
 {
@@ -413,7 +415,9 @@ 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);
+        spin_lock(&inode->i_lock);
         hlist_add_head(&inode->i_hash, b);
+        spin_unlock(&inode->i_lock);
         spin_unlock(&inode_lock);
 }
 EXPORT_SYMBOL(__insert_inode_hash);
@@ -438,7 +442,9 @@ static void __remove_inode_hash(struct inode *inode)
 void remove_inode_hash(struct inode *inode)
 {
         spin_lock(&inode_lock);
+        spin_lock(&inode->i_lock);
         hlist_del_init(&inode->i_hash);
+        spin_unlock(&inode->i_lock);
         spin_unlock(&inode_lock);
 }
 EXPORT_SYMBOL(remove_inode_hash);
@@ -495,7 +501,9 @@ static void dispose_list(struct list_head *head)
                 __inode_sb_list_del(inode);
                 spin_unlock(&inode_lock);
 
-                wake_up_inode(inode);
+                spin_lock(&inode->i_lock);
+                wake_up_bit(&inode->i_state, __I_NEW);
+                spin_unlock(&inode->i_lock);
                 destroy_inode(inode);
         }
 }
@@ -518,10 +526,17 @@ void evict_inodes(struct super_block *sb)
         list_for_each_entry_safe(inode, next, &sb->s_inodes, i_sb_list) {
                 if (atomic_read(&inode->i_count))
                         continue;
-                if (inode->i_state & (I_NEW | I_FREEING | I_WILL_FREE))
+
+                spin_lock(&inode->i_lock);
+                if (inode->i_state & (I_NEW | I_FREEING | I_WILL_FREE)) {
+                        spin_unlock(&inode->i_lock);
                         continue;
+                }
 
                 inode->i_state |= I_FREEING;
+                if (!(inode->i_state & (I_DIRTY | I_SYNC)))
+                        inodes_stat.nr_unused--;
+                spin_unlock(&inode->i_lock);
 
                 /*
                  * Move the inode off the IO lists and LRU once I_FREEING is
@@ -529,8 +544,6 @@ void evict_inodes(struct super_block *sb)
                  */
                 list_move(&inode->i_lru, &dispose);
                 list_del_init(&inode->i_wb_list);
-                if (!(inode->i_state & (I_DIRTY | I_SYNC)))
-                        inodes_stat.nr_unused--;
         }
         spin_unlock(&inode_lock);
 
@@ -563,18 +576,26 @@ int invalidate_inodes(struct super_block *sb, bool kill_dirty)
 
         spin_lock(&inode_lock);
         list_for_each_entry_safe(inode, next, &sb->s_inodes, i_sb_list) {
-                if (inode->i_state & (I_NEW | I_FREEING | I_WILL_FREE))
+                spin_lock(&inode->i_lock);
+                if (inode->i_state & (I_NEW | I_FREEING | I_WILL_FREE)) {
+                        spin_unlock(&inode->i_lock);
                         continue;
+                }
                 if (inode->i_state & I_DIRTY && !kill_dirty) {
+                        spin_unlock(&inode->i_lock);
                         busy = 1;
                         continue;
                 }
                 if (atomic_read(&inode->i_count)) {
+                        spin_unlock(&inode->i_lock);
                         busy = 1;
                         continue;
                 }
 
                 inode->i_state |= I_FREEING;
+                if (!(inode->i_state & (I_DIRTY | I_SYNC)))
+                        inodes_stat.nr_unused--;
+                spin_unlock(&inode->i_lock);
 
                 /*
                  * Move the inode off the IO lists and LRU once I_FREEING is
@@ -582,8 +603,6 @@ int invalidate_inodes(struct super_block *sb, bool kill_dirty)
                  */
                 list_move(&inode->i_lru, &dispose);
                 list_del_init(&inode->i_wb_list);
-                if (!(inode->i_state & (I_DIRTY | I_SYNC)))
-                        inodes_stat.nr_unused--;
         }
         spin_unlock(&inode_lock);
 
@@ -641,8 +660,10 @@ static void prune_icache(int nr_to_scan)
                  * Referenced or dirty inodes are still in use. Give them
                  * another pass through the LRU as we canot reclaim them now.
                  */
+                spin_lock(&inode->i_lock);
                 if (atomic_read(&inode->i_count) ||
                     (inode->i_state & ~I_REFERENCED)) {
+                        spin_unlock(&inode->i_lock);
                         list_del_init(&inode->i_lru);
                         inodes_stat.nr_unused--;
                         continue;
@@ -650,12 +671,14 @@ static void prune_icache(int nr_to_scan)
 
                 /* 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;
+                        spin_unlock(&inode->i_lock);
+                        list_move(&inode->i_lru, &inode_lru);
                         continue;
                 }
                 if (inode_has_buffers(inode) || inode->i_data.nrpages) {
                         __iget(inode);
+                        spin_unlock(&inode->i_lock);
                         spin_unlock(&inode_lock);
                         if (remove_inode_buffers(inode))
                                 reap += invalidate_mapping_pages(&inode->i_data,
@@ -666,11 +689,15 @@ static void prune_icache(int nr_to_scan)
                         if (inode != list_entry(inode_lru.next,
                                                 struct inode, i_lru))
                                 continue;       /* wrong inode or list_empty */
-                        if (!can_unuse(inode))
+                        spin_lock(&inode->i_lock);
+                        if (!can_unuse(inode)) {
+                                spin_unlock(&inode->i_lock);
                                 continue;
+                        }
                 }
                 WARN_ON(inode->i_state & I_NEW);
                 inode->i_state |= I_FREEING;
+                spin_unlock(&inode->i_lock);
 
                 /*
                  * Move the inode off the IO lists and LRU once I_FREEING is
@@ -737,11 +764,13 @@ repeat:
                         continue;
                 if (!test(inode, data))
                         continue;
+                spin_lock(&inode->i_lock);
                 if (inode->i_state & (I_FREEING|I_WILL_FREE)) {
                         __wait_on_freeing_inode(inode);
                         goto repeat;
                 }
                 __iget(inode);
+                spin_unlock(&inode->i_lock);
                 return inode;
         }
         return NULL;
@@ -763,11 +792,13 @@ repeat:
                         continue;
                 if (inode->i_sb != sb)
                         continue;
+                spin_lock(&inode->i_lock);
                 if (inode->i_state & (I_FREEING|I_WILL_FREE)) {
                         __wait_on_freeing_inode(inode);
                         goto repeat;
                 }
                 __iget(inode);
+                spin_unlock(&inode->i_lock);
                 return inode;
         }
         return NULL;
@@ -832,14 +863,23 @@ struct inode *new_inode(struct super_block *sb)
         inode = alloc_inode(sb);
         if (inode) {
                 spin_lock(&inode_lock);
-                __inode_sb_list_add(inode);
+                spin_lock(&inode->i_lock);
                 inode->i_state = 0;
+                spin_unlock(&inode->i_lock);
+                __inode_sb_list_add(inode);
                 spin_unlock(&inode_lock);
         }
         return inode;
 }
 EXPORT_SYMBOL(new_inode);
 
+/**
+ * unlock_new_inode - clear the I_NEW state and wake up any waiters
+ * @inode:      new inode to unlock
+ *
+ * Called when the inode is fully initialised to clear the new state of the
+ * inode and wake up anyone waiting for the inode to finish initialisation.
+ */
 void unlock_new_inode(struct inode *inode)
 {
 #ifdef CONFIG_DEBUG_LOCK_ALLOC
@@ -859,19 +899,11 @@ void unlock_new_inode(struct inode *inode)
                 }
         }
 #endif
-        /*
-         * This is special!  We do not need the spinlock when clearing I_NEW,
-         * because we're guaranteed that nobody else tries to do anything about
-         * the state of the inode when it is locked, as we just created it (so
-         * there can be no old holders that haven't tested I_NEW).
-         * However we must emit the memory barrier so that other CPUs reliably
-         * see the clearing of I_NEW after the other inode initialisation has
-         * completed.
-         */
-        smp_mb();
+        spin_lock(&inode->i_lock);
         WARN_ON(!(inode->i_state & I_NEW));
         inode->i_state &= ~I_NEW;
-        wake_up_inode(inode);
+        wake_up_bit(&inode->i_state, __I_NEW);
+        spin_unlock(&inode->i_lock);
 }
 EXPORT_SYMBOL(unlock_new_inode);
 
@@ -900,9 +932,11 @@ static struct inode *get_new_inode(struct super_block *sb,
                         if (set(inode, data))
                                 goto set_failed;
 
+                        spin_lock(&inode->i_lock);
+                        inode->i_state = I_NEW;
                         hlist_add_head(&inode->i_hash, head);
+                        spin_unlock(&inode->i_lock);
                         __inode_sb_list_add(inode);
-                        inode->i_state = I_NEW;
                         spin_unlock(&inode_lock);
 
                         /* Return the locked inode with I_NEW set, the
@@ -947,9 +981,11 @@ static struct inode *get_new_inode_fast(struct super_block *sb,
                 old = find_inode_fast(sb, head, ino);
                 if (!old) {
                         inode->i_ino = ino;
+                        spin_lock(&inode->i_lock);
+                        inode->i_state = I_NEW;
                         hlist_add_head(&inode->i_hash, head);
+                        spin_unlock(&inode->i_lock);
                         __inode_sb_list_add(inode);
-                        inode->i_state = I_NEW;
                         spin_unlock(&inode_lock);
 
                         /* Return the locked inode with I_NEW set, the
@@ -1034,15 +1070,19 @@ EXPORT_SYMBOL(iunique);
 struct inode *igrab(struct inode *inode)
 {
         spin_lock(&inode_lock);
-        if (!(inode->i_state & (I_FREEING|I_WILL_FREE)))
+        spin_lock(&inode->i_lock);
+        if (!(inode->i_state & (I_FREEING|I_WILL_FREE))) {
                 __iget(inode);
-        else
+                spin_unlock(&inode->i_lock);
+        } else {
+                spin_unlock(&inode->i_lock);
                 /*
                  * Handle the case where s_op->clear_inode is not been
                  * called yet, and somebody is calling igrab
                  * while the inode is getting freed.
                  */
                 inode = NULL;
+        }
         spin_unlock(&inode_lock);
         return inode;
 }
@@ -1271,7 +1311,6 @@ int insert_inode_locked(struct inode *inode)
         ino_t ino = inode->i_ino;
         struct hlist_head *head = inode_hashtable + hash(sb, ino);
 
-        inode->i_state |= I_NEW;
         while (1) {
                 struct hlist_node *node;
                 struct inode *old = NULL;
@@ -1281,16 +1320,23 @@ int insert_inode_locked(struct inode *inode)
                                 continue;
                         if (old->i_sb != sb)
                                 continue;
-                        if (old->i_state & (I_FREEING|I_WILL_FREE))
+                        spin_lock(&old->i_lock);
+                        if (old->i_state & (I_FREEING|I_WILL_FREE)) {
+                                spin_unlock(&old->i_lock);
                                 continue;
+                        }
                         break;
                 }
                 if (likely(!node)) {
+                        spin_lock(&inode->i_lock);
+                        inode->i_state |= I_NEW;
                         hlist_add_head(&inode->i_hash, head);
+                        spin_unlock(&inode->i_lock);
                         spin_unlock(&inode_lock);
                         return 0;
                 }
                 __iget(old);
+                spin_unlock(&old->i_lock);
                 spin_unlock(&inode_lock);
                 wait_on_inode(old);
                 if (unlikely(!inode_unhashed(old))) {
@@ -1308,8 +1354,6 @@ int insert_inode_locked4(struct inode *inode, unsigned long hashval,
         struct super_block *sb = inode->i_sb;
         struct hlist_head *head = inode_hashtable + hash(sb, hashval);
 
-        inode->i_state |= I_NEW;
-
         while (1) {
                 struct hlist_node *node;
                 struct inode *old = NULL;
@@ -1320,16 +1364,23 @@ int insert_inode_locked4(struct inode *inode, unsigned long hashval,
                                 continue;
                         if (!test(old, data))
                                 continue;
-                        if (old->i_state & (I_FREEING|I_WILL_FREE))
+                        spin_lock(&old->i_lock);
+                        if (old->i_state & (I_FREEING|I_WILL_FREE)) {
+                                spin_unlock(&old->i_lock);
                                 continue;
+                        }
                         break;
                 }
                 if (likely(!node)) {
+                        spin_lock(&inode->i_lock);
+                        inode->i_state |= I_NEW;
                         hlist_add_head(&inode->i_hash, head);
+                        spin_unlock(&inode->i_lock);
                         spin_unlock(&inode_lock);
                         return 0;
                 }
                 __iget(old);
+                spin_unlock(&old->i_lock);
                 spin_unlock(&inode_lock);
                 wait_on_inode(old);
                 if (unlikely(!inode_unhashed(old))) {
@@ -1375,6 +1426,9 @@ static void iput_final(struct inode *inode)
         const struct super_operations *op = inode->i_sb->s_op;
         int drop;
 
+        spin_lock(&inode->i_lock);
+        WARN_ON(inode->i_state & I_NEW);
+
         if (op && op->drop_inode)
                 drop = op->drop_inode(inode);
         else
@@ -1386,21 +1440,23 @@ static void iput_final(struct inode *inode)
                         if (!(inode->i_state & (I_DIRTY|I_SYNC))) {
                                 inode_lru_list_add(inode);
                         }
+                        spin_unlock(&inode->i_lock);
                         spin_unlock(&inode_lock);
                         return;
                 }
-                WARN_ON(inode->i_state & I_NEW);
                 inode->i_state |= I_WILL_FREE;
+                spin_unlock(&inode->i_lock);
                 spin_unlock(&inode_lock);
                 write_inode_now(inode, 1);
                 spin_lock(&inode_lock);
+                spin_lock(&inode->i_lock);
                 WARN_ON(inode->i_state & I_NEW);
                 inode->i_state &= ~I_WILL_FREE;
                 __remove_inode_hash(inode);
         }
 
-        WARN_ON(inode->i_state & I_NEW);
         inode->i_state |= I_FREEING;
+        spin_unlock(&inode->i_lock);
 
         /*
          * Move the inode off the IO lists and LRU once I_FREEING is
@@ -1413,8 +1469,10 @@ static void iput_final(struct inode *inode)
         spin_unlock(&inode_lock);
         evict(inode);
         remove_inode_hash(inode);
-        wake_up_inode(inode);
+        spin_lock(&inode->i_lock);
+        wake_up_bit(&inode->i_state, __I_NEW);
         BUG_ON(inode->i_state != (I_FREEING | I_CLEAR));
+        spin_unlock(&inode->i_lock);
         destroy_inode(inode);
 }
 
@@ -1611,9 +1669,8 @@ EXPORT_SYMBOL(inode_wait);
  * to recheck inode state.
  *
  * It doesn't matter if I_NEW is not set initially, a call to
- * wake_up_inode() after removing from the hash list will DTRT.
- *
- * This is called with inode_lock held.
+ * wake_up_bit(&inode->i_state, __I_NEW) after removing from the hash list
+ * will DTRT.
  */
 static void __wait_on_freeing_inode(struct inode *inode)
 {
@@ -1621,6 +1678,7 @@ static void __wait_on_freeing_inode(struct inode *inode)
         DEFINE_WAIT_BIT(wait, &inode->i_state, __I_NEW);
         wq = bit_waitqueue(&inode->i_state, __I_NEW);
         prepare_to_wait(wq, &wait.wait, TASK_UNINTERRUPTIBLE);
+        spin_unlock(&inode->i_lock);
         spin_unlock(&inode_lock);
         schedule();
         finish_wait(wq, &wait.wait);
diff --git a/fs/notify/inode_mark.c b/fs/notify/inode_mark.c
index 4c29fcf557d1..4dd53fb44124 100644
--- a/fs/notify/inode_mark.c
+++ b/fs/notify/inode_mark.c
@@ -254,8 +254,11 @@ void fsnotify_unmount_inodes(struct list_head *list)
                  * I_WILL_FREE, or I_NEW which is fine because by that point
                  * the inode cannot have any associated watches.
                  */
-                if (inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW))
+                spin_lock(&inode->i_lock);
+                if (inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW)) {
+                        spin_unlock(&inode->i_lock);
                         continue;
+                }
 
                 /*
                  * If i_count is zero, the inode cannot have any watches and
@@ -263,8 +266,10 @@ void fsnotify_unmount_inodes(struct list_head *list)
                  * evict all inodes with zero i_count from icache which is
                  * unnecessarily violent and may in fact be illegal to do.
                  */
-                if (!atomic_read(&inode->i_count))
+                if (!atomic_read(&inode->i_count)) {
+                        spin_unlock(&inode->i_lock);
                         continue;
+                }
 
                 need_iput_tmp = need_iput;
                 need_iput = NULL;
@@ -274,13 +279,17 @@ void fsnotify_unmount_inodes(struct list_head *list)
                         __iget(inode);
                 else
                         need_iput_tmp = NULL;
+                spin_unlock(&inode->i_lock);
 
                 /* In case the dropping of a reference would nuke next_i. */
                 if ((&next_i->i_sb_list != list) &&
-                    atomic_read(&next_i->i_count) &&
-                    !(next_i->i_state & (I_FREEING | I_WILL_FREE))) {
-                        __iget(next_i);
-                        need_iput = next_i;
+                    atomic_read(&next_i->i_count)) {
+                        spin_lock(&next_i->i_lock);
+                        if (!(next_i->i_state & (I_FREEING | I_WILL_FREE))) {
+                                __iget(next_i);
+                                need_iput = next_i;
+                        }
+                        spin_unlock(&next_i->i_lock);
                 }
 
                 /*
diff --git a/fs/quota/dquot.c b/fs/quota/dquot.c
index a2a622e079f0..a1470fda366c 100644
--- a/fs/quota/dquot.c
+++ b/fs/quota/dquot.c
@@ -902,18 +902,19 @@ static void add_dquot_ref(struct super_block *sb, int type)
 
         spin_lock(&inode_lock);
         list_for_each_entry(inode, &sb->s_inodes, i_sb_list) {
-                if (inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW))
+                spin_lock(&inode->i_lock);
+                if ((inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW)) ||
+                    !atomic_read(&inode->i_writecount) ||
+                    !dqinit_needed(inode, type)) {
+                        spin_unlock(&inode->i_lock);
                         continue;
+                }
 #ifdef CONFIG_QUOTA_DEBUG
                 if (unlikely(inode_get_rsv_space(inode) > 0))
                         reserved = 1;
 #endif
-                if (!atomic_read(&inode->i_writecount))
-                        continue;
-                if (!dqinit_needed(inode, type))
-                        continue;
-
                 __iget(inode);
+                spin_unlock(&inode->i_lock);
                 spin_unlock(&inode_lock);
 
                 iput(old_inode);
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 4dda076c24a1..ed6fdcc1484c 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1647,7 +1647,7 @@ struct super_operations {
 };
 
 /*
- * Inode state bits.  Protected by inode_lock.
+ * Inode state bits.  Protected by inode->i_lock
  *
  * Three bits determine the dirty state of the inode, I_DIRTY_SYNC,
  * I_DIRTY_DATASYNC and I_DIRTY_PAGES.
diff --git a/include/linux/quotaops.h b/include/linux/quotaops.h
index eb354f6f26b3..26f9e3612e0f 100644
--- a/include/linux/quotaops.h
+++ b/include/linux/quotaops.h
@@ -277,7 +277,7 @@ static inline int dquot_alloc_space(struct inode *inode, qsize_t nr)
                 /*
                  * Mark inode fully dirty. Since we are allocating blocks, inode
                  * would become fully dirty soon anyway and it reportedly
-                 * reduces inode_lock contention.
+                 * reduces lock contention.
                  */
                 mark_inode_dirty(inode);
         }
diff --git a/mm/filemap.c b/mm/filemap.c
index f807afda86f2..499e9aa91450 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -99,7 +99,9 @@
  *    ->private_lock            (page_remove_rmap->set_page_dirty)
  *    ->tree_lock               (page_remove_rmap->set_page_dirty)
  *    ->inode_lock              (page_remove_rmap->set_page_dirty)
+ *    ->inode->i_lock           (page_remove_rmap->set_page_dirty)
  *    ->inode_lock              (zap_pte_range->set_page_dirty)
+ *    ->inode->i_lock           (zap_pte_range->set_page_dirty)
  *    ->private_lock            (zap_pte_range->__set_page_dirty_buffers)
  *
  *  (code doesn't rely on that order, so you could switch it around)
diff --git a/mm/rmap.c b/mm/rmap.c
index 4a8e99a0fb97..7dada0456448 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -32,6 +32,7 @@
  *               mmlist_lock (in mmput, drain_mmlist and others)
  *               mapping->private_lock (in __set_page_dirty_buffers)
  *               inode_lock (in set_page_dirty's __mark_inode_dirty)
+ *               inode->i_lock (in set_page_dirty's __mark_inode_dirty)
  *                 sb_lock (within inode_lock in fs/fs-writeback.c)
  *                 mapping->tree_lock (widely used, in set_page_dirty,
  *                           in arch-dependent flush_dcache_mmap_lock,