From: NeilBrown <neilb@suse.de>
Date: Mon, 7 Mar 2011 05:48:37 +0000 (+1100)
Subject: Add 'filesys' pointer to lafs_inode
X-Git-Url: http://git.neil.brown.name/?a=commitdiff_plain;h=077a81d6e714d7413a2fc2e1c3fd1e17919a5bae;p=LaFS.git

Add 'filesys' pointer to lafs_inode

This is the first patch in a series to switch from having one
struct super_block for each subset filesystem, to only having one
for each snapshot.  i.e. one which is writable and some number
which are read-only snapshots.
The struct super_block described the primary filesystem and
all of the subset filesystems.

Signed-off-by: NeilBrown <neilb@suse.de>
---

diff --git a/inode.c b/inode.c
index 9948ede..e385afe 100644
--- a/inode.c
+++ b/inode.c
@@ -149,6 +149,8 @@ lafs_iget(struct super_block *sb, ino_t inum, int async)
 		return ERR_PTR(-ENOENT);
 	}
 
+	LAFSI(ino)->filesys = igrab(inodefile);
+
 	/* surprisingly the inode bdi does not default to the
 	 * super_blocks bdi...
 	 */
diff --git a/roll.c b/roll.c
index 664884b..f1dd269 100644
--- a/roll.c
+++ b/roll.c
@@ -793,6 +793,7 @@ lafs_mount(struct fs *fs)
 
 	fs->rolled = 0;
 	fs->ss[0].root = ino = iget_locked(fs->prime_sb, 0);
+	LAFSI(ino)->filesys = ino;
 	k->root = ino;
 
 	err = -ENOMEM;
diff --git a/snapshot.c b/snapshot.c
index 1bdeb97..4489ed3 100644
--- a/snapshot.c
+++ b/snapshot.c
@@ -168,6 +168,7 @@ lafs_snap_get_sb(struct file_system_type *fstype,
 		atomic_inc(&fs->prime_sb->s_active);
 
 		fs->ss[s].root = sk->k.root = iget_locked(sb, 0);
+		LAFSI(fs->ss[s].root)->filesys = fs->ss[s].root;
 		b = lafs_get_block(fs->ss[s].root, 0, NULL, GFP_KERNEL,
 				   MKREF(snap));
 		b->b.physaddr = fs->ss[s].root_addr;
diff --git a/state.h b/state.h
index 8f27841..903682a 100644
--- a/state.h
+++ b/state.h
@@ -554,6 +554,7 @@ enum {
 /* indexing info stays in the block, not in the inode */
 struct lafs_inode {
 	struct inode	vfs_inode;
+	struct inode	*filesys;	/* Inode of containing TypeInodeFile */
 	struct indexblock	*iblock;
 	struct datablock	*dblock;
 	long	cblocks, /* data blocks which are commited to this file */
diff --git a/super.c b/super.c
index 68f0c35..3137913 100644
--- a/super.c
+++ b/super.c
@@ -1336,6 +1336,7 @@ static void kfree_inode(struct rcu_head *head)
 void lafs_destroy_inode(struct inode *inode)
 {
 	struct datablock *db;
+	struct inode *fsys = LAFSI(inode)->filesys;
 
 	BUG_ON(!list_empty(&inode->i_sb_list));
 	// Cannot test i_list as dispose_list just does list_del
@@ -1345,6 +1346,10 @@ void lafs_destroy_inode(struct inode *inode)
 		set_bit(I_Destroyed, &LAFSI(inode)->iflags);
 		putdref(db, MKREF(destroy));
 	} else {
+		if (fsys != inode)
+			iput(fsys);
+		LAFSI(inode)->filesys = NULL;
+
 		spin_lock(&inode->i_data.private_lock);
 		if (LAFSI(inode)->iblock)
 			LAFS_BUG(atomic_read(&LAFSI(inode)->iblock->b.refcnt),