[PATCH] hfs: fix logic of alloc/free b-tree node

[Viacheslav Dubeyko <slava@dubeyko.com>]

The hfs_bmap_alloc() and hfs_bmap_free() modify
the b-tree's counters and nodes' bitmap of b-tree.
However, hfs_btree_write() synchronizes the state of
in-core b-tree's counters and node's bitmap with
b-tree's descriptor in header node. Postponing this
synchronization could result in inconsistent state of
file system volume. Add calling of hfs_btree_write()
in hfs_bmap_alloc() and hfs_bmap_free() methods.

HFS port of the HFS+ commit:
commit 63584d76765b ("hfsplus: fix logic of alloc/free b-tree node").

Signed-off-by: Viacheslav Dubeyko <slava@dubeyko.com>
cc: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
cc: Yangtao Li <frank.li@vivo.com>
cc: linux-fsdevel@vger.kernel.org
---
 fs/hfs/btree.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/fs/hfs/btree.c b/fs/hfs/btree.c
index b140d8597474..27a515a3dd0c 100644
--- a/fs/hfs/btree.c
+++ b/fs/hfs/btree.c
@@ -458,6 +458,7 @@ struct hfs_bnode *hfs_bmap_alloc(struct hfs_btree *tree)
 						set_page_dirty(page);
 						kunmap_local(data);
 						tree->free_nodes--;
+						hfs_btree_write(tree);
 						mark_inode_dirty(tree->inode);
 						hfs_bnode_put(node);
 						return hfs_bnode_create(tree, idx);
@@ -478,6 +479,7 @@ struct hfs_bnode *hfs_bmap_alloc(struct hfs_btree *tree)
 		if (!nidx) {
 			printk(KERN_DEBUG "create new bmap node...\n");
 			next_node = hfs_bmap_new_bmap(node, idx);
+			hfs_btree_write(tree);
 		} else
 			next_node = hfs_bnode_find(tree, nidx);
 		hfs_bnode_put(node);
@@ -545,6 +547,7 @@ void hfs_bmap_free(struct hfs_bnode *node)
 			nidx, node->type);
 	} else {
 		tree->free_nodes++;
+		hfs_btree_write(tree);
 		mark_inode_dirty(tree->inode);
 	}
 
-- 
2.43.0