1 files changed, 37 insertions, 26 deletions

diff --git a/fs/inode.c b/fs/inode.c
index da85e56378f..9910c039f02 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -84,16 +84,13 @@ static struct hlist_head *inode_hashtable __read_mostly;
 DEFINE_SPINLOCK(inode_lock);
 
 /*
- * iprune_sem provides exclusion between the kswapd or try_to_free_pages
- * icache shrinking path, and the umount path.  Without this exclusion,
- * by the time prune_icache calls iput for the inode whose pages it has
- * been invalidating, or by the time it calls clear_inode & destroy_inode
- * from its final dispose_list, the struct super_block they refer to
- * (for inode->i_sb->s_op) may already have been freed and reused.
+ * iprune_sem provides exclusion between the icache shrinking and the
+ * umount path.
  *
- * We make this an rwsem because the fastpath is icache shrinking. In
- * some cases a filesystem may be doing a significant amount of work in
- * its inode reclaim code, so this should improve parallelism.
+ * We don't actually need it to protect anything in the umount path,
+ * but only need to cycle through it to make sure any inode that
+ * prune_icache took off the LRU list has been fully torn down by the
+ * time we are past evict_inodes.
  */
 static DECLARE_RWSEM(iprune_sem);
 
@@ -295,6 +292,20 @@ static void destroy_inode(struct inode *inode)
                 call_rcu(&inode->i_rcu, i_callback);
 }
 
+void address_space_init_once(struct address_space *mapping)
+{
+        memset(mapping, 0, sizeof(*mapping));
+        INIT_RADIX_TREE(&mapping->page_tree, GFP_ATOMIC);
+        spin_lock_init(&mapping->tree_lock);
+        spin_lock_init(&mapping->i_mmap_lock);
+        INIT_LIST_HEAD(&mapping->private_list);
+        spin_lock_init(&mapping->private_lock);
+        INIT_RAW_PRIO_TREE_ROOT(&mapping->i_mmap);
+        INIT_LIST_HEAD(&mapping->i_mmap_nonlinear);
+        mutex_init(&mapping->unmap_mutex);
+}
+EXPORT_SYMBOL(address_space_init_once);
+
 /*
  * These are initializations that only need to be done
  * once, because the fields are idempotent across use
@@ -308,13 +319,7 @@ void inode_init_once(struct inode *inode)
         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);
-        INIT_LIST_HEAD(&inode->i_data.private_list);
-        spin_lock_init(&inode->i_data.private_lock);
-        INIT_RAW_PRIO_TREE_ROOT(&inode->i_data.i_mmap);
-        INIT_LIST_HEAD(&inode->i_data.i_mmap_nonlinear);
+        address_space_init_once(&inode->i_data);
         i_size_ordered_init(inode);
 #ifdef CONFIG_FSNOTIFY
         INIT_HLIST_HEAD(&inode->i_fsnotify_marks);
@@ -508,17 +513,12 @@ void evict_inodes(struct super_block *sb)
         struct inode *inode, *next;
         LIST_HEAD(dispose);
 
-        down_write(&iprune_sem);
-
         spin_lock(&inode_lock);
         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)) {
-                        WARN_ON(1);
+                if (inode->i_state & (I_NEW | I_FREEING | I_WILL_FREE))
                         continue;
-                }
 
                 inode->i_state |= I_FREEING;
 
@@ -534,28 +534,40 @@ void evict_inodes(struct super_block *sb)
         spin_unlock(&inode_lock);
 
         dispose_list(&dispose);
+
+        /*
+         * Cycle through iprune_sem to make sure any inode that prune_icache
+         * moved off the list before we took the lock has been fully torn
+         * down.
+         */
+        down_write(&iprune_sem);
         up_write(&iprune_sem);
 }
 
 /**
  * invalidate_inodes    - attempt to free all inodes on a superblock
  * @sb:         superblock to operate on
+ * @kill_dirty: flag to guide handling of dirty inodes
  *
  * Attempts to free all inodes for a given superblock.  If there were any
  * busy inodes return a non-zero value, else zero.
+ * If @kill_dirty is set, discard dirty inodes too, otherwise treat
+ * them as busy.
  */
-int invalidate_inodes(struct super_block *sb)
+int invalidate_inodes(struct super_block *sb, bool kill_dirty)
 {
         int busy = 0;
         struct inode *inode, *next;
         LIST_HEAD(dispose);
 
-        down_write(&iprune_sem);
-
         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))
                         continue;
+                if (inode->i_state & I_DIRTY && !kill_dirty) {
+                        busy = 1;
+                        continue;
+                }
                 if (atomic_read(&inode->i_count)) {
                         busy = 1;
                         continue;
@@ -575,7 +587,6 @@ int invalidate_inodes(struct super_block *sb)
         spin_unlock(&inode_lock);
 
         dispose_list(&dispose);
-        up_write(&iprune_sem);
 
         return busy;
 }