[WIP PATCH 2/4] udf: Fix reading numFiles and numDirs from UDF 2.00+ VAT discs

[Pali Rohár <pali.rohar@xxxxxxxxx>]

These two fields are stored in VAT and override previous values stored in
LVIDIU.

This change contains only implementation for UDF 2.00+. For UDF 1.50 there
is an optional structure "Logical Volume Extended Information" which is not
implemented in this change yet.

Signed-off-by: Pali Rohár <pali.rohar@xxxxxxxxx>
---
 fs/udf/super.c  | 25 ++++++++++++++++++++++---
 fs/udf/udf_sb.h |  3 +++
 2 files changed, 25 insertions(+), 3 deletions(-)

diff --git a/fs/udf/super.c b/fs/udf/super.c
index 8df6e9962..e8661bf01 100644
--- a/fs/udf/super.c
+++ b/fs/udf/super.c
@@ -1202,6 +1202,8 @@ static int udf_load_vat(struct super_block *sb, int p_index, int type1_index)
 		map->s_type_specific.s_virtual.s_start_offset = 0;
 		map->s_type_specific.s_virtual.s_num_entries =
 			(sbi->s_vat_inode->i_size - 36) >> 2;
+		/* TODO: Add support for reading Logical Volume Extended Information (UDF 1.50 Errata, DCN 5003, 3.3.4.5.1.3) */
+		map->s_type_specific.s_virtual.s_has_additional_data = false;
 	} else if (map->s_partition_type == UDF_VIRTUAL_MAP20) {
 		vati = UDF_I(sbi->s_vat_inode);
 		if (vati->i_alloc_type != ICBTAG_FLAG_AD_IN_ICB) {
@@ -1215,6 +1217,12 @@ static int udf_load_vat(struct super_block *sb, int p_index, int type1_index)
 							vati->i_ext.i_data;
 		}
 
+		map->s_type_specific.s_virtual.s_has_additional_data =
+			true;
+		map->s_type_specific.s_virtual.s_num_files =
+			le32_to_cpu(vat20->numFiles);
+		map->s_type_specific.s_virtual.s_num_dirs =
+			le32_to_cpu(vat20->numDirs);
 		map->s_type_specific.s_virtual.s_start_offset =
 			le16_to_cpu(vat20->lengthHeader);
 		map->s_type_specific.s_virtual.s_num_entries =
@@ -2417,9 +2425,20 @@ static int udf_statfs(struct dentry *dentry, struct kstatfs *buf)
 	buf->f_blocks = sbi->s_partmaps[sbi->s_partition].s_partition_len;
 	buf->f_bfree = udf_count_free(sb);
 	buf->f_bavail = buf->f_bfree;
-	buf->f_files = (lvidiu != NULL ? (le32_to_cpu(lvidiu->numFiles) +
-					  le32_to_cpu(lvidiu->numDirs)) : 0)
-			+ buf->f_bfree;
+
+	if ((sbi->s_partmaps[sbi->s_partition].s_partition_type == UDF_VIRTUAL_MAP15 ||
+	     sbi->s_partmaps[sbi->s_partition].s_partition_type == UDF_VIRTUAL_MAP20) &&
+	     sbi->s_partmaps[sbi->s_partition].s_type_specific.s_virtual.s_has_additional_data)
+		buf->f_files = sbi->s_partmaps[sbi->s_partition].s_type_specific.s_virtual.s_num_files +
+			       sbi->s_partmaps[sbi->s_partition].s_type_specific.s_virtual.s_num_dirs +
+			       buf->f_bfree;
+	else if (lvidiu != NULL)
+		buf->f_files = le32_to_cpu(lvidiu->numFiles) +
+			       le32_to_cpu(lvidiu->numDirs) +
+			       buf->f_bfree;
+	else
+		buf->f_files = buf->f_bfree;
+
 	buf->f_ffree = buf->f_bfree;
 	buf->f_namelen = UDF_NAME_LEN;
 	buf->f_fsid.val[0] = (u32)id;
diff --git a/fs/udf/udf_sb.h b/fs/udf/udf_sb.h
index 6bd0d4430..c74abbc84 100644
--- a/fs/udf/udf_sb.h
+++ b/fs/udf/udf_sb.h
@@ -78,6 +78,9 @@ struct udf_sparing_data {
 struct udf_virtual_data {
 	__u32	s_num_entries;
 	__u16	s_start_offset;
+	bool	s_has_additional_data;
+	__u32	s_num_files;
+	__u32	s_num_dirs;
 };
 
 struct udf_bitmap {
-- 
2.20.1