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>

4 files changed, 55 insertions, 2 deletions

diff --git a/fs/hfsplus/catalog.c b/fs/hfsplus/catalog.c
index 968ce411db53..32602c667b4a 100644
--- a/fs/hfsplus/catalog.c
+++ b/fs/hfsplus/catalog.c
@@ -103,6 +103,8 @@ static int hfsplus_cat_build_record(hfsplus_cat_entry *entry,
                 folder = &entry->folder;
                 memset(folder, 0, sizeof(*folder));
                 folder->type = cpu_to_be16(HFSPLUS_FOLDER);
+                if (test_bit(HFSPLUS_SB_HFSX, &sbi->flags))
+                        folder->flags |= cpu_to_be16(HFSPLUS_HAS_FOLDER_COUNT);
                 folder->id = cpu_to_be32(inode->i_ino);
                 HFSPLUS_I(inode)->create_date =
                         folder->create_date =
@@ -203,6 +205,36 @@ int hfsplus_find_cat(struct super_block *sb, u32 cnid,
         return hfs_brec_find(fd, hfs_find_rec_by_key);
 }
 
+static void hfsplus_subfolders_inc(struct inode *dir)
+{
+        struct hfsplus_sb_info *sbi = HFSPLUS_SB(dir->i_sb);
+
+        if (test_bit(HFSPLUS_SB_HFSX, &sbi->flags)) {
+                /*
+                 * Increment subfolder count. Note, the value is only meaningful
+                 * for folders with HFSPLUS_HAS_FOLDER_COUNT flag set.
+                 */
+                HFSPLUS_I(dir)->subfolders++;
+        }
+}
+
+static void hfsplus_subfolders_dec(struct inode *dir)
+{
+        struct hfsplus_sb_info *sbi = HFSPLUS_SB(dir->i_sb);
+
+        if (test_bit(HFSPLUS_SB_HFSX, &sbi->flags)) {
+                /*
+                 * Decrement subfolder count. Note, the value is only meaningful
+                 * for folders with HFSPLUS_HAS_FOLDER_COUNT flag set.
+                 *
+                 * Check for zero. Some subfolders may have been created
+                 * by an implementation ignorant of this counter.
+                 */
+                if (HFSPLUS_I(dir)->subfolders)
+                        HFSPLUS_I(dir)->subfolders--;
+        }
+}
+
 int hfsplus_create_cat(u32 cnid, struct inode *dir,
                 struct qstr *str, struct inode *inode)
 {
@@ -247,6 +279,8 @@ int hfsplus_create_cat(u32 cnid, struct inode *dir,
                 goto err1;
 
         dir->i_size++;
+        if (S_ISDIR(inode->i_mode))
+                hfsplus_subfolders_inc(dir);
         dir->i_mtime = dir->i_ctime = CURRENT_TIME_SEC;
         hfsplus_mark_inode_dirty(dir, HFSPLUS_I_CAT_DIRTY);
 
@@ -336,6 +370,8 @@ int hfsplus_delete_cat(u32 cnid, struct inode *dir, struct qstr *str)
                 goto out;
 
         dir->i_size--;
+        if (type == HFSPLUS_FOLDER)
+                hfsplus_subfolders_dec(dir);
         dir->i_mtime = dir->i_ctime = CURRENT_TIME_SEC;
         hfsplus_mark_inode_dirty(dir, HFSPLUS_I_CAT_DIRTY);
 
@@ -380,6 +416,7 @@ int hfsplus_rename_cat(u32 cnid,
 
         hfs_bnode_read(src_fd.bnode, &entry, src_fd.entryoffset,
                                 src_fd.entrylength);
+        type = be16_to_cpu(entry.type);
 
         /* create new dir entry with the data from the old entry */
         hfsplus_cat_build_key(sb, dst_fd.search_key, dst_dir->i_ino, dst_name);
@@ -394,6 +431,8 @@ int hfsplus_rename_cat(u32 cnid,
         if (err)
                 goto out;
         dst_dir->i_size++;
+        if (type == HFSPLUS_FOLDER)
+                hfsplus_subfolders_inc(dst_dir);
         dst_dir->i_mtime = dst_dir->i_ctime = CURRENT_TIME_SEC;
 
         /* finally remove the old entry */
@@ -405,6 +444,8 @@ int hfsplus_rename_cat(u32 cnid,
         if (err)
                 goto out;
         src_dir->i_size--;
+        if (type == HFSPLUS_FOLDER)
+                hfsplus_subfolders_dec(src_dir);
         src_dir->i_mtime = src_dir->i_ctime = CURRENT_TIME_SEC;
 
         /* remove old thread entry */
diff --git a/fs/hfsplus/hfsplus_fs.h b/fs/hfsplus/hfsplus_fs.h
index 08846425b67f..62d571eb69ba 100644
--- a/fs/hfsplus/hfsplus_fs.h
+++ b/fs/hfsplus/hfsplus_fs.h
@@ -242,6 +242,7 @@ struct hfsplus_inode_info {
          */
         sector_t fs_blocks;
         u8 userflags;           /* BSD user file flags */
+        u32 subfolders;         /* Subfolder count (HFSX only) */
         struct list_head open_dir_list;
         loff_t phys_size;
 
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 {
diff --git a/fs/hfsplus/inode.c b/fs/hfsplus/inode.c
index fa929f325f87..a4f45bd88a63 100644
--- a/fs/hfsplus/inode.c
+++ b/fs/hfsplus/inode.c
@@ -375,6 +375,7 @@ struct inode *hfsplus_new_inode(struct super_block *sb, umode_t mode)
         hip->extent_state = 0;
         hip->flags = 0;
         hip->userflags = 0;
+        hip->subfolders = 0;
         memset(hip->first_extents, 0, sizeof(hfsplus_extent_rec));
         memset(hip->cached_extents, 0, sizeof(hfsplus_extent_rec));
         hip->alloc_blocks = 0;
@@ -494,6 +495,10 @@ int hfsplus_cat_read_inode(struct inode *inode, struct hfs_find_data *fd)
                 inode->i_ctime = hfsp_mt2ut(folder->attribute_mod_date);
                 HFSPLUS_I(inode)->create_date = folder->create_date;
                 HFSPLUS_I(inode)->fs_blocks = 0;
+                if (folder->flags & cpu_to_be16(HFSPLUS_HAS_FOLDER_COUNT)) {
+                        HFSPLUS_I(inode)->subfolders =
+                                be32_to_cpu(folder->subfolders);
+                }
                 inode->i_op = &hfsplus_dir_inode_operations;
                 inode->i_fop = &hfsplus_dir_operations;
         } else if (type == HFSPLUS_FILE) {
@@ -566,6 +571,10 @@ int hfsplus_cat_write_inode(struct inode *inode)
                 folder->content_mod_date = hfsp_ut2mt(inode->i_mtime);
                 folder->attribute_mod_date = hfsp_ut2mt(inode->i_ctime);
                 folder->valence = cpu_to_be32(inode->i_size - 2);
+                if (folder->flags & cpu_to_be16(HFSPLUS_HAS_FOLDER_COUNT)) {
+                        folder->subfolders =
+                                cpu_to_be32(HFSPLUS_I(inode)->subfolders);
+                }
                 hfs_bnode_write(fd.bnode, &entry, fd.entryoffset,
                                          sizeof(struct hfsplus_cat_folder));
         } else if (HFSPLUS_IS_RSRC(inode)) {