hfsplus: implement attributes file creation functionality

Implement functionality of creation AttributesFile metadata file on HFS+
volume in the case of absence of it.

It makes trying to open AttributesFile's B-tree during mount of HFS+
volume.  If HFS+ volume hasn't AttributesFile then a pointer on
AttributesFile's B-tree keeps as NULL.  Thereby, when it is discovered
absence of AttributesFile on HFS+ volume in the begin of xattr creation
operation then AttributesFile will be created.

The creation of AttributesFile will have success in the case of
availability (2 * clump) free blocks on HFS+ volume.  Otherwise,
creation operation is ended with error (-ENOSPC).

Signed-off-by: Vyacheslav Dubeyko <slava@dubeyko.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@infradead.org>
Acked-by: Hin-Tak Leung <htl10@users.sourceforge.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 2 insertions, 0 deletions

diff --git a/fs/hfsplus/super.c b/fs/hfsplus/super.c
index 4c4d142cf890..80875aa640ef 100644
--- a/fs/hfsplus/super.c
+++ b/fs/hfsplus/super.c
@@ -474,12 +474,14 @@ static int hfsplus_fill_super(struct super_block *sb, void *data, int silent)
 		pr_err("failed to load catalog file\n");
 		goto out_close_ext_tree;
 	}
+	atomic_set(&sbi->attr_tree_state, HFSPLUS_EMPTY_ATTR_TREE);
 	if (vhdr->attr_file.total_blocks != 0) {
 		sbi->attr_tree = hfs_btree_open(sb, HFSPLUS_ATTR_CNID);
 		if (!sbi->attr_tree) {
 			pr_err("failed to load attributes file\n");
 			goto out_close_cat_tree;
 		}
+		atomic_set(&sbi->attr_tree_state, HFSPLUS_VALID_ATTR_TREE);
 	}
 	sb->s_xattr = hfsplus_xattr_handlers;