vfs: dont chain pipe/anon/socket on superblock s_inodes list

[mirror_ubuntu-artful-kernel.git] / fs / inode.c

diff --git a/fs/inode.c b/fs/inode.c
index 96c77b81167c81b75bfdbaf6f8c1ea0566892748..319b93b555709b14e69e2f750274522ee1e0d27b 100644 (file)
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -362,9 +362,11 @@ EXPORT_SYMBOL_GPL(inode_sb_list_add);
 
 static inline void inode_sb_list_del(struct inode *inode)
 {
-       spin_lock(&inode_sb_list_lock);
-       list_del_init(&inode->i_sb_list);
-       spin_unlock(&inode_sb_list_lock);
+       if (!list_empty(&inode->i_sb_list)) {
+               spin_lock(&inode_sb_list_lock);
+               list_del_init(&inode->i_sb_list);
+               spin_unlock(&inode_sb_list_lock);
+       }
 }
 
 static unsigned long hash(struct super_block *sb, unsigned long hashval)
@@ -796,6 +798,29 @@ unsigned int get_next_ino(void)
 }
 EXPORT_SYMBOL(get_next_ino);
 
+/**
+ *     new_inode_pseudo        - obtain an inode
+ *     @sb: superblock
+ *
+ *     Allocates a new inode for given superblock.
+ *     Inode wont be chained in superblock s_inodes list
+ *     This means :
+ *     - fs can't be unmount
+ *     - quotas, fsnotify, writeback can't work
+ */
+struct inode *new_inode_pseudo(struct super_block *sb)
+{
+       struct inode *inode = alloc_inode(sb);
+
+       if (inode) {
+               spin_lock(&inode->i_lock);
+               inode->i_state = 0;
+               spin_unlock(&inode->i_lock);
+               INIT_LIST_HEAD(&inode->i_sb_list);
+       }
+       return inode;
+}
+
 /**
  *     new_inode       - obtain an inode
  *     @sb: superblock
@@ -814,13 +839,9 @@ struct inode *new_inode(struct super_block *sb)
 
        spin_lock_prefetch(&inode_sb_list_lock);
 
-       inode = alloc_inode(sb);
-       if (inode) {
-               spin_lock(&inode->i_lock);
-               inode->i_state = 0;
-               spin_unlock(&inode->i_lock);
+       inode = new_inode_pseudo(sb);
+       if (inode)
                inode_sb_list_add(inode);
-       }
        return inode;
 }
 EXPORT_SYMBOL(new_inode);