hfsplus: add HFSX subfolder count support

Adds support for HFSX 'HasFolderCount' flag and a corresponding
'folderCount' field in folder records.  (For reference see
HFS_FOLDERCOUNT and kHFSHasFolderCountBit/kHFSHasFolderCountMask in
Apple's source code.)

Ignoring subfolder count leads to fs errors found by Mac:

  ...
  Checking catalog hierarchy.
  HasFolderCount flag needs to be set (id = 105)
  (It should be 0x10 instead of 0)
  Incorrect folder count in a directory (id = 2)
  (It should be 7 instead of 6)
  ...

Steps to reproduce:
 Format with "newfs_hfs -s /dev/diskXXX".
 Mount in Linux.
 Create a new directory in root.
 Unmount.
 Run "fsck_hfs /dev/diskXXX".

The patch handles directory creation, deletion, and rename.

Signed-off-by: Sergei Antonov <saproj@gmail.com>
Reviewed-by: Vyacheslav Dubeyko <slava@dubeyko.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 4 insertions, 2 deletions

diff --git a/fs/hfsplus/hfsplus_raw.h b/fs/hfsplus/hfsplus_raw.h
index 8ffb3a8ffe75..5a126828d85e 100644
--- a/fs/hfsplus/hfsplus_raw.h
+++ b/fs/hfsplus/hfsplus_raw.h
@@ -261,7 +261,7 @@ struct hfsplus_cat_folder {
         struct DInfo user_info;
         struct DXInfo finder_info;
         __be32 text_encoding;
-        u32 reserved;
+        __be32 subfolders;      /* Subfolder count in HFSX. Reserved in HFS+. */
 } __packed;
 
 /* HFS file info (stolen from hfs.h) */
@@ -301,11 +301,13 @@ struct hfsplus_cat_file {
         struct hfsplus_fork_raw rsrc_fork;
 } __packed;
 
-/* File attribute bits */
+/* File and folder flag bits */
 #define HFSPLUS_FILE_LOCKED             0x0001
 #define HFSPLUS_FILE_THREAD_EXISTS      0x0002
 #define HFSPLUS_XATTR_EXISTS            0x0004
 #define HFSPLUS_ACL_EXISTS              0x0008
+#define HFSPLUS_HAS_FOLDER_COUNT        0x0010  /* Folder has subfolder count
+                                                 * (HFSX only) */
 
 /* HFS+ catalog thread (part of a cat_entry) */
 struct hfsplus_cat_thread {