Date:	Fri, 19 Feb 2016 16:10:44 -0500
From:	Waiman Long <Waiman.Long@....com>
To:	Alexander Viro <viro@...iv.linux.org.uk>, Jan Kara <jack@...e.com>,
	Jeff Layton <jlayton@...chiereds.net>,
	"J. Bruce Fields" <bfields@...ldses.org>,
	Tejun Heo <tj@...nel.org>,
	Christoph Lameter <cl@...ux-foundation.org>
Cc:	linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org,
	Ingo Molnar <mingo@...hat.com>,
	Peter Zijlstra <peterz@...radead.org>,
	Andi Kleen <andi@...stfloor.org>,
	Dave Chinner <dchinner@...hat.com>,
	Scott J Norton <scott.norton@...com>,
	Douglas Hatch <doug.hatch@...com>,
	Waiman Long <Waiman.Long@....com>
Subject: [PATCH v2 2/3] vfs: Refactor sb->s_inodes iteration functions

This patch refactors the following superblock inode list (sb->s_inodes)
iteration functions in vfs:

 1. iterate_bdevs()
 2. drop_pagecache_sb()
 3. wait_sb_inodes()
 4. evict_inodes()
 5. invalidate_inodes()
 6. fsnotify_unmount_inodes()
 7. add_dquot_ref()
 8. remove_dquot_ref()

The per-inode processing codes of the above functions are extracted
out into inline functions to ease their conversion to use the per-cpu
list. There is no functional change.

Signed-off-by: Waiman Long <Waiman.Long@....com>
---
 fs/block_dev.c         |   59 +++++++++++---------
 fs/drop_caches.c       |   39 ++++++++-----
 fs/fs-writeback.c      |   73 +++++++++++++-----------
 fs/inode.c             |  108 ++++++++++++++++++++---------------
 fs/notify/inode_mark.c |  146 ++++++++++++++++++++++++++----------------------
 fs/quota/dquot.c       |  105 ++++++++++++++++++++--------------
 6 files changed, 298 insertions(+), 232 deletions(-)

diff --git a/fs/block_dev.c b/fs/block_dev.c
index 39b3a17..6eaeedf 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -1862,38 +1862,45 @@ int __invalidate_device(struct block_device *bdev, bool kill_dirty)
 }
 EXPORT_SYMBOL(__invalidate_device);
 
+static inline void
+__iterate_bdev(spinlock_t *lock, struct inode *inode, struct inode **old_inode,
+	       void (*func)(struct block_device *, void *), void *arg)
+{
+	struct address_space *mapping = inode->i_mapping;
+
+	spin_lock(&inode->i_lock);
+	if (inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW) ||
+	    mapping->nrpages == 0) {
+		spin_unlock(&inode->i_lock);
+		return;
+	}
+	__iget(inode);
+	spin_unlock(&inode->i_lock);
+	spin_unlock(lock);
+	/*
+	 * We hold a reference to 'inode' so it couldn't have been
+	 * removed from s_inodes list while we dropped the
+	 * pcpu_lock. We cannot iput the inode now as we can
+	 * be holding the last reference and we cannot iput it under
+	 * pcpu_lock. So we keep the reference and iput it later.
+	 */
+	iput(*old_inode);
+	*old_inode = inode;
+
+	func(I_BDEV(inode), arg);
+
+	spin_lock(lock);
+}
+
 void iterate_bdevs(void (*func)(struct block_device *, void *), void *arg)
 {
 	struct inode *inode, *old_inode = NULL;
 
 	spin_lock(&blockdev_superblock->s_inode_list_lock);
-	list_for_each_entry(inode, &blockdev_superblock->s_inodes, i_sb_list) {
-		struct address_space *mapping = inode->i_mapping;
-
-		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(&blockdev_superblock->s_inode_list_lock);
-		/*
-		 * We hold a reference to 'inode' so it couldn't have been
-		 * removed from s_inodes list while we dropped the
-		 * s_inode_list_lock  We cannot iput the inode now as we can
-		 * be holding the last reference and we cannot iput it under
-		 * s_inode_list_lock. So we keep the reference and iput it
-		 * later.
-		 */
-		iput(old_inode);
-		old_inode = inode;
+	list_for_each_entry(inode, &blockdev_superblock->s_inodes, i_sb_list)
+		__iterate_bdev(&blockdev_superblock->s_inode_list_lock,
+			       inode, &old_inode, func, arg);
 
-		func(I_BDEV(inode), arg);
-
-		spin_lock(&blockdev_superblock->s_inode_list_lock);
-	}
 	spin_unlock(&blockdev_superblock->s_inode_list_lock);
 	iput(old_inode);
 }
diff --git a/fs/drop_caches.c b/fs/drop_caches.c
index d72d52b..d3449d5 100644
--- a/fs/drop_caches.c
+++ b/fs/drop_caches.c
@@ -13,28 +13,35 @@
 /* A global variable is a bit ugly, but it keeps the code simple */
 int sysctl_drop_caches;
 
+static inline void __drop_pagecache_sb(spinlock_t *lock, struct inode *inode,
+				       struct inode **toput_inode)
+{
+	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);
+		return;
+	}
+	__iget(inode);
+	spin_unlock(&inode->i_lock);
+	spin_unlock(lock);
+
+	invalidate_mapping_pages(inode->i_mapping, 0, -1);
+	iput(*toput_inode);
+	*toput_inode = inode;
+
+	spin_lock(lock);
+}
+
 static void drop_pagecache_sb(struct super_block *sb, void *unused)
 {
 	struct inode *inode, *toput_inode = NULL;
 
 	spin_lock(&sb->s_inode_list_lock);
-	list_for_each_entry(inode, &sb->s_inodes, i_sb_list) {
-		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(&sb->s_inode_list_lock);
+	list_for_each_entry(inode, &sb->s_inodes, i_sb_list)
+		__drop_pagecache_sb(&sb->s_inode_list_lock, inode,
+				    &toput_inode);
 
-		invalidate_mapping_pages(inode->i_mapping, 0, -1);
-		iput(toput_inode);
-		toput_inode = inode;
-
-		spin_lock(&sb->s_inode_list_lock);
-	}
 	spin_unlock(&sb->s_inode_list_lock);
 	iput(toput_inode);
 }
diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index 6915c95..5ad6eda 100644
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -2095,6 +2095,43 @@ out_unlock_inode:
 }
 EXPORT_SYMBOL(__mark_inode_dirty);
 
+static inline void __wait_sb_inode(spinlock_t *lock, struct inode *inode,
+				   struct inode **old_inode)
+{
+	struct address_space *mapping = inode->i_mapping;
+
+	spin_lock(&inode->i_lock);
+	if ((inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW)) ||
+	    (mapping->nrpages == 0)) {
+		spin_unlock(&inode->i_lock);
+		return;
+	}
+	__iget(inode);
+	spin_unlock(&inode->i_lock);
+	spin_unlock(lock);
+
+	/*
+	 * We hold a reference to 'inode' so it couldn't have been
+	 * removed from s_inodes list while we dropped the
+	 * pcpu_lock.  We cannot iput the inode now as we can
+	 * be holding the last reference and we cannot iput it under
+	 * pcpu_lock. So we keep the reference and iput it later.
+	 */
+	iput(*old_inode);
+	*old_inode = inode;
+
+	/*
+	 * We keep the error status of individual mapping so that
+	 * applications can catch the writeback error using fsync(2).
+	 * See filemap_fdatawait_keep_errors() for details.
+	 */
+	filemap_fdatawait_keep_errors(mapping);
+
+	cond_resched();
+
+	spin_lock(lock);
+}
+
 /*
  * The @s_sync_lock is used to serialise concurrent sync operations
  * to avoid lock contention problems with concurrent wait_sb_inodes() calls.
@@ -2124,41 +2161,9 @@ static void wait_sb_inodes(struct super_block *sb)
 	 * In which case, the inode may not be on the dirty list, but
 	 * we still have to wait for that writeout.
 	 */
-	list_for_each_entry(inode, &sb->s_inodes, i_sb_list) {
-		struct address_space *mapping = inode->i_mapping;
-
-		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(&sb->s_inode_list_lock);
+	list_for_each_entry(inode, &sb->s_inodes, i_sb_list)
+		__wait_sb_inode(&sb->s_inode_list_lock, inode, &old_inode);
 
-		/*
-		 * We hold a reference to 'inode' so it couldn't have been
-		 * removed from s_inodes list while we dropped the
-		 * s_inode_list_lock.  We cannot iput the inode now as we can
-		 * be holding the last reference and we cannot iput it under
-		 * s_inode_list_lock. So we keep the reference and iput it
-		 * later.
-		 */
-		iput(old_inode);
-		old_inode = inode;
-
-		/*
-		 * We keep the error status of individual mapping so that
-		 * applications can catch the writeback error using fsync(2).
-		 * See filemap_fdatawait_keep_errors() for details.
-		 */
-		filemap_fdatawait_keep_errors(mapping);
-
-		cond_resched();
-
-		spin_lock(&sb->s_inode_list_lock);
-	}
 	spin_unlock(&sb->s_inode_list_lock);
 	iput(old_inode);
 	mutex_unlock(&sb->s_sync_lock);
diff --git a/fs/inode.c b/fs/inode.c
index 9f62db3..6dd609e 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -579,6 +579,37 @@ static void dispose_list(struct list_head *head)
 	}
 }
 
+static inline int __evict_inode(spinlock_t *lock, struct inode *inode,
+				struct list_head *dispose)
+{
+	if (atomic_read(&inode->i_count))
+		return 0;
+
+	spin_lock(&inode->i_lock);
+	if (inode->i_state & (I_NEW | I_FREEING | I_WILL_FREE)) {
+		spin_unlock(&inode->i_lock);
+		return 0;
+	}
+
+	inode->i_state |= I_FREEING;
+	inode_lru_list_del(inode);
+	spin_unlock(&inode->i_lock);
+	list_add(&inode->i_lru, dispose);
+
+	/*
+	 * We can have a ton of inodes to evict at unmount time given
+	 * enough memory, check to see if we need to go to sleep for a
+	 * bit so we don't livelock.
+	 */
+	if (need_resched()) {
+		spin_unlock(lock);
+		cond_resched();
+		dispose_list(dispose);
+		return 1;	/* Redo it again */
+	}
+	return 0;
+}
+
 /**
  * evict_inodes	- evict all evictable inodes for a superblock
  * @sb:		superblock to operate on
@@ -596,35 +627,39 @@ void evict_inodes(struct super_block *sb)
 again:
 	spin_lock(&sb->s_inode_list_lock);
 	list_for_each_entry_safe(inode, next, &sb->s_inodes, i_sb_list) {
-		if (atomic_read(&inode->i_count))
-			continue;
+		if (__evict_inode(&sb->s_inode_list_lock, inode, &dispose))
+			goto again;
+	}
+	spin_unlock(&sb->s_inode_list_lock);
 
-		spin_lock(&inode->i_lock);
-		if (inode->i_state & (I_NEW | I_FREEING | I_WILL_FREE)) {
-			spin_unlock(&inode->i_lock);
-			continue;
-		}
+	dispose_list(&dispose);
+}
 
-		inode->i_state |= I_FREEING;
-		inode_lru_list_del(inode);
+static inline void __invalidate_inode(struct inode *inode, bool kill_dirty,
+				      struct list_head *dispose, int *busy)
+{
+	spin_lock(&inode->i_lock);
+	if (inode->i_state & (I_NEW | I_FREEING | I_WILL_FREE)) {
 		spin_unlock(&inode->i_lock);
-		list_add(&inode->i_lru, &dispose);
+		return;
+	}
 
-		/*
-		 * We can have a ton of inodes to evict at unmount time given
-		 * enough memory, check to see if we need to go to sleep for a
-		 * bit so we don't livelock.
-		 */
-		if (need_resched()) {
-			spin_unlock(&sb->s_inode_list_lock);
-			cond_resched();
-			dispose_list(&dispose);
-			goto again;
-		}
+	if (inode->i_state & I_DIRTY_ALL && !kill_dirty) {
+		spin_unlock(&inode->i_lock);
+		*busy = 1;
+		return;
 	}
-	spin_unlock(&sb->s_inode_list_lock);
 
-	dispose_list(&dispose);
+	if (atomic_read(&inode->i_count)) {
+		spin_unlock(&inode->i_lock);
+		*busy = 1;
+		return;
+	}
+
+	inode->i_state |= I_FREEING;
+	inode_lru_list_del(inode);
+	spin_unlock(&inode->i_lock);
+	list_add(&inode->i_lru, dispose);
 }
 
 /**
@@ -644,28 +679,9 @@ int invalidate_inodes(struct super_block *sb, bool kill_dirty)
 	LIST_HEAD(dispose);
 
 	spin_lock(&sb->s_inode_list_lock);
-	list_for_each_entry_safe(inode, next, &sb->s_inodes, i_sb_list) {
-		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_ALL && !kill_dirty) {
-			spin_unlock(&inode->i_lock);
-			busy = 1;
-			continue;
-		}
-		if (atomic_read(&inode->i_count)) {
-			spin_unlock(&inode->i_lock);
-			busy = 1;
-			continue;
-		}
+	list_for_each_entry_safe(inode, next, &sb->s_inodes, i_sb_list)
+		__invalidate_inode(inode, kill_dirty, &dispose, &busy);
 
-		inode->i_state |= I_FREEING;
-		inode_lru_list_del(inode);
-		spin_unlock(&inode->i_lock);
-		list_add(&inode->i_lru, &dispose);
-	}
 	spin_unlock(&sb->s_inode_list_lock);
 
 	dispose_list(&dispose);
diff --git a/fs/notify/inode_mark.c b/fs/notify/inode_mark.c
index 741077d..ec52dcb 100644
--- a/fs/notify/inode_mark.c
+++ b/fs/notify/inode_mark.c
@@ -141,86 +141,98 @@ int fsnotify_add_inode_mark(struct fsnotify_mark *mark,
 	return ret;
 }
 
-/**
- * fsnotify_unmount_inodes - an sb is unmounting.  handle any watched inodes.
- * @sb: superblock being unmounted.
- *
- * Called during unmount with no locks held, so needs to be safe against
- * concurrent modifiers. We temporarily drop sb->s_inode_list_lock and CAN block.
- */
-void fsnotify_unmount_inodes(struct super_block *sb)
+static inline void
+__fsnotify_unmount_inode(spinlock_t *lock, struct inode *inode,
+			 struct list_head *head, struct inode **pnext,
+			 struct inode **need_iput)
 {
-	struct inode *inode, *next_i, *need_iput = NULL;
-
-	spin_lock(&sb->s_inode_list_lock);
-	list_for_each_entry_safe(inode, next_i, &sb->s_inodes, i_sb_list) {
-		struct inode *need_iput_tmp;
+	struct inode *need_iput_tmp;
+	struct inode *next_i = *pnext;
 
-		/*
-		 * We cannot __iget() an inode in state I_FREEING,
-		 * I_WILL_FREE, or I_NEW which is fine because by that point
-		 * the inode cannot have any associated watches.
-		 */
-		spin_lock(&inode->i_lock);
-		if (inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW)) {
-			spin_unlock(&inode->i_lock);
-			continue;
-		}
+	/*
+	 * We cannot __iget() an inode in state I_FREEING,
+	 * I_WILL_FREE, or I_NEW which is fine because by that point
+	 * the inode cannot have any associated watches.
+	 */
+	spin_lock(&inode->i_lock);
+	if (inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW)) {
+		spin_unlock(&inode->i_lock);
+		return;
+	}
 
-		/*
-		 * If i_count is zero, the inode cannot have any watches and
-		 * doing an __iget/iput with MS_ACTIVE clear would actually
-		 * 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)) {
-			spin_unlock(&inode->i_lock);
-			continue;
-		}
+	/*
+	 * If i_count is zero, the inode cannot have any watches and
+	 * doing an __iget/iput with MS_ACTIVE clear would actually
+	 * 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)) {
+		spin_unlock(&inode->i_lock);
+		return;
+	}
 
-		need_iput_tmp = need_iput;
-		need_iput = NULL;
+	need_iput_tmp = *need_iput;
+	*need_iput = NULL;
 
-		/* In case fsnotify_inode_delete() drops a reference. */
-		if (inode != need_iput_tmp)
-			__iget(inode);
-		else
-			need_iput_tmp = NULL;
-		spin_unlock(&inode->i_lock);
+	/* In case fsnotify_inode_delete() drops a reference. */
+	if (inode != need_iput_tmp)
+		__iget(inode);
+	else
+		need_iput_tmp = NULL;
+	spin_unlock(&inode->i_lock);
 
-		/* In case the dropping of a reference would nuke next_i. */
-		while (&next_i->i_sb_list != &sb->s_inodes) {
-			spin_lock(&next_i->i_lock);
-			if (!(next_i->i_state & (I_FREEING | I_WILL_FREE)) &&
-						atomic_read(&next_i->i_count)) {
-				__iget(next_i);
-				need_iput = next_i;
-				spin_unlock(&next_i->i_lock);
-				break;
-			}
+	/* In case the dropping of a reference would nuke next_i. */
+	while (&next_i->i_sb_list != head) {
+		spin_lock(&next_i->i_lock);
+		if (!(next_i->i_state & (I_FREEING | I_WILL_FREE)) &&
+					atomic_read(&next_i->i_count)) {
+			__iget(next_i);
+			*need_iput = next_i;
 			spin_unlock(&next_i->i_lock);
-			next_i = list_next_entry(next_i, i_sb_list);
+			break;
 		}
+		spin_unlock(&next_i->i_lock);
+		next_i = list_next_entry(next_i, i_sb_list);
+	}
+	*pnext = next_i;
 
-		/*
-		 * We can safely drop s_inode_list_lock here because either
-		 * we actually hold references on both inode and next_i or
-		 * end of list.  Also no new inodes will be added since the
-		 * umount has begun.
-		 */
-		spin_unlock(&sb->s_inode_list_lock);
+	/*
+	 * We can safely drop pcpu_lock  here because either
+	 * we actually hold references on both inode and next_i or
+	 * end of list.  Also no new inodes will be added since the
+	 * umount has begun.
+	 */
+	spin_unlock(lock);
 
-		if (need_iput_tmp)
-			iput(need_iput_tmp);
+	if (need_iput_tmp)
+		iput(need_iput_tmp);
 
-		/* for each watch, send FS_UNMOUNT and then remove it */
-		fsnotify(inode, FS_UNMOUNT, inode, FSNOTIFY_EVENT_INODE, NULL, 0);
+	/* for each watch, send FS_UNMOUNT and then remove it */
+	fsnotify(inode, FS_UNMOUNT, inode, FSNOTIFY_EVENT_INODE, NULL, 0);
 
-		fsnotify_inode_delete(inode);
+	fsnotify_inode_delete(inode);
 
-		iput(inode);
+	iput(inode);
+
+	spin_lock(lock);
+}
+
+/**
+ * fsnotify_unmount_inodes - an sb is unmounting.  handle any watched inodes.
+ * @sb: superblock being unmounted.
+ *
+ * Called during unmount with no locks held, so needs to be safe against
+ * concurrent modifiers. We temporarily drop sb->s_inodes_cpu->lock and CAN
+ * block.
+ */
+void fsnotify_unmount_inodes(struct super_block *sb)
+{
+	struct inode *inode, *next_i, *need_iput = NULL;
+
+	spin_lock(&sb->s_inode_list_lock);
+	list_for_each_entry_safe(inode, next_i, &sb->s_inodes, i_sb_list)
+		__fsnotify_unmount_inode(&sb->s_inode_list_lock, inode,
+					 &sb->s_inodes, &next_i, &need_iput);
 
-		spin_lock(&sb->s_inode_list_lock);
-	}
 	spin_unlock(&sb->s_inode_list_lock);
 }
diff --git a/fs/quota/dquot.c b/fs/quota/dquot.c
index 3c3b81b..143183b 100644
--- a/fs/quota/dquot.c
+++ b/fs/quota/dquot.c
@@ -920,6 +920,42 @@ static int dqinit_needed(struct inode *inode, int type)
 	return 0;
 }
 
+static inline void
+__add_dquot_ref(spinlock_t *lock, struct inode *inode, int type,
+#ifdef CONFIG_QUOTA_DEBUG
+		int *reserved,
+#endif
+		struct inode **old_inode)
+{
+	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);
+		return;
+	}
+	__iget(inode);
+	spin_unlock(&inode->i_lock);
+	spin_unlock(lock);
+
+#ifdef CONFIG_QUOTA_DEBUG
+	if (unlikely(inode_get_rsv_space(inode) > 0))
+		*reserved = 1;
+#endif
+	iput(*old_inode);
+	__dquot_initialize(inode, type);
+
+	/*
+	 * We hold a reference to 'inode' so it couldn't have been
+	 * removed from s_inodes list while we dropped the
+	 * pcpu_lock. We cannot iput the inode now as we can be
+	 * holding the last reference and we cannot iput it under
+	 * pcpu_lock. So we keep the reference and iput it later.
+	 */
+	*old_inode = inode;
+	spin_lock(lock);
+}
+
 /* This routine is guarded by dqonoff_mutex mutex */
 static void add_dquot_ref(struct super_block *sb, int type)
 {
@@ -929,36 +965,12 @@ static void add_dquot_ref(struct super_block *sb, int type)
 #endif
 
 	spin_lock(&sb->s_inode_list_lock);
-	list_for_each_entry(inode, &sb->s_inodes, i_sb_list) {
-		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;
-		}
-		__iget(inode);
-		spin_unlock(&inode->i_lock);
-		spin_unlock(&sb->s_inode_list_lock);
-
+	list_for_each_entry(inode, &sb->s_inodes, i_sb_list)
+		__add_dquot_ref(&sb->s_inode_list_lock, inode, type,
 #ifdef CONFIG_QUOTA_DEBUG
-		if (unlikely(inode_get_rsv_space(inode) > 0))
-			reserved = 1;
+				&reserved,
 #endif
-		iput(old_inode);
-		__dquot_initialize(inode, type);
-
-		/*
-		 * We hold a reference to 'inode' so it couldn't have been
-		 * removed from s_inodes list while we dropped the
-		 * s_inode_list_lock. We cannot iput the inode now as we can be
-		 * holding the last reference and we cannot iput it under
-		 * s_inode_list_lock. So we keep the reference and iput it
-		 * later.
-		 */
-		old_inode = inode;
-		spin_lock(&sb->s_inode_list_lock);
-	}
+				&old_inode);
 	spin_unlock(&sb->s_inode_list_lock);
 	iput(old_inode);
 
@@ -1022,6 +1034,25 @@ static void put_dquot_list(struct list_head *tofree_head)
 	}
 }
 
+static inline void
+__remove_dquot_ref(struct inode *inode, int type,
+		   struct list_head *tofree_head, int *reserved)
+{
+	/*
+	 *  We have to scan also I_NEW inodes because they can already
+	 *  have quota pointer initialized. Luckily, we need to touch
+	 *  only quota pointers and these have separate locking
+	 *  (dq_data_lock).
+	 */
+	spin_lock(&dq_data_lock);
+	if (!IS_NOQUOTA(inode)) {
+		if (unlikely(inode_get_rsv_space(inode) > 0))
+			*reserved = 1;
+		remove_inode_dquot_ref(inode, type, tofree_head);
+	}
+	spin_unlock(&dq_data_lock);
+}
+
 static void remove_dquot_ref(struct super_block *sb, int type,
 		struct list_head *tofree_head)
 {
@@ -1029,21 +1060,9 @@ static void remove_dquot_ref(struct super_block *sb, int type,
 	int reserved = 0;
 
 	spin_lock(&sb->s_inode_list_lock);
-	list_for_each_entry(inode, &sb->s_inodes, i_sb_list) {
-		/*
-		 *  We have to scan also I_NEW inodes because they can already
-		 *  have quota pointer initialized. Luckily, we need to touch
-		 *  only quota pointers and these have separate locking
-		 *  (dq_data_lock).
-		 */
-		spin_lock(&dq_data_lock);
-		if (!IS_NOQUOTA(inode)) {
-			if (unlikely(inode_get_rsv_space(inode) > 0))
-				reserved = 1;
-			remove_inode_dquot_ref(inode, type, tofree_head);
-		}
-		spin_unlock(&dq_data_lock);
-	}
+	list_for_each_entry(inode, &sb->s_inodes, i_sb_list)
+		__remove_dquot_ref(inode, type, tofree_head, &reserved);
+
 	spin_unlock(&sb->s_inode_list_lock);
 #ifdef CONFIG_QUOTA_DEBUG
 	if (reserved) {
-- 
1.7.1

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