vfs: split generic_forget_inode() so that hugetlbfs does not have to copy it

Hugetlbfs needs to do special things instead of truncate_inode_pages().
 Currently, it copied generic_forget_inode() except for
truncate_inode_pages() call which is asking for trouble (the code there
isn't trivial).  So create a separate function generic_detach_inode()
which does all the list magic done in generic_forget_inode() and call
it from hugetlbfs_forget_inode().

Signed-off-by: Jan Kara <jack@suse.cz>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 4 insertions, 29 deletions

diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c
index eba6d552d9c..478a169a262 100644
--- a/fs/hugetlbfs/inode.c
+++ b/fs/hugetlbfs/inode.c
@@ -380,36 +380,11 @@ static void hugetlbfs_delete_inode(struct inode *inode)
 
 static void hugetlbfs_forget_inode(struct inode *inode) __releases(inode_lock)
 {
-	struct super_block *sb = inode->i_sb;
-
-	if (!hlist_unhashed(&inode->i_hash)) {
-		if (!(inode->i_state & (I_DIRTY|I_SYNC)))
-			list_move(&inode->i_list, &inode_unused);
-		inodes_stat.nr_unused++;
-		if (!sb || (sb->s_flags & MS_ACTIVE)) {
-			spin_unlock(&inode_lock);
-			return;
-		}
-		inode->i_state |= I_WILL_FREE;
-		spin_unlock(&inode_lock);
-		/*
-		 * write_inode_now is a noop as we set BDI_CAP_NO_WRITEBACK
-		 * in our backing_dev_info.
-		 */
-		write_inode_now(inode, 1);
-		spin_lock(&inode_lock);
-		inode->i_state &= ~I_WILL_FREE;
-		inodes_stat.nr_unused--;
-		hlist_del_init(&inode->i_hash);
+	if (generic_detach_inode(inode)) {
+		truncate_hugepages(inode, 0);
+		clear_inode(inode);
+		destroy_inode(inode);
 	}
-	list_del_init(&inode->i_list);
-	list_del_init(&inode->i_sb_list);
-	inode->i_state |= I_FREEING;
-	inodes_stat.nr_inodes--;
-	spin_unlock(&inode_lock);
-	truncate_hugepages(inode, 0);
-	clear_inode(inode);
-	destroy_inode(inode);
 }
 
 static void hugetlbfs_drop_inode(struct inode *inode)