ext4: add ext4_group_t, and change all group variables to this type.

In many places variables for block group are of type int, which limits the
maximum number of block groups to 2^31.  Each block group can have up to
2^15 blocks, with a 4K block size,  and the max filesystem size is limited to
2^31 * (2^15 * 2^12) = 2^58  -- or 256 PB

This patch introduces a new type ext4_group_t, of type unsigned long, to
represent block group numbers in ext4.
All occurrences of block group variables are converted to type ext4_group_t.

Signed-off-by: Avantika Mathur <mathur@us.ibm.com>

1 files changed, 24 insertions, 22 deletions

diff --git a/fs/ext4/ialloc.c b/fs/ext4/ialloc.c
index c61f37fd3f0..64dea8689e1 100644
--- a/fs/ext4/ialloc.c
+++ b/fs/ext4/ialloc.c
@@ -64,8 +64,8 @@ void mark_bitmap_end(int start_bit, int end_bit, char *bitmap)
 }
 
 /* Initializes an uninitialized inode bitmap */
-unsigned ext4_init_inode_bitmap(struct super_block *sb,
-				struct buffer_head *bh, int block_group,
+unsigned ext4_init_inode_bitmap(struct super_block *sb, struct buffer_head *bh,
+				ext4_group_t block_group,
 				struct ext4_group_desc *gdp)
 {
 	struct ext4_sb_info *sbi = EXT4_SB(sb);
@@ -75,7 +75,7 @@ unsigned ext4_init_inode_bitmap(struct super_block *sb,
 	/* If checksum is bad mark all blocks and inodes use to prevent
 	 * allocation, essentially implementing a per-group read-only flag. */
 	if (!ext4_group_desc_csum_verify(sbi, block_group, gdp)) {
-		ext4_error(sb, __FUNCTION__, "Checksum bad for group %u\n",
+		ext4_error(sb, __FUNCTION__, "Checksum bad for group %lu\n",
 			   block_group);
 		gdp->bg_free_blocks_count = 0;
 		gdp->bg_free_inodes_count = 0;
@@ -98,7 +98,7 @@ unsigned ext4_init_inode_bitmap(struct super_block *sb,
  * Return buffer_head of bitmap on success or NULL.
  */
 static struct buffer_head *
-read_inode_bitmap(struct super_block * sb, unsigned long block_group)
+read_inode_bitmap(struct super_block *sb, ext4_group_t block_group)
 {
 	struct ext4_group_desc *desc;
 	struct buffer_head *bh = NULL;
@@ -152,7 +152,7 @@ void ext4_free_inode (handle_t *handle, struct inode * inode)
 	unsigned long ino;
 	struct buffer_head *bitmap_bh = NULL;
 	struct buffer_head *bh2;
-	unsigned long block_group;
+	ext4_group_t block_group;
 	unsigned long bit;
 	struct ext4_group_desc * gdp;
 	struct ext4_super_block * es;
@@ -260,12 +260,12 @@ error_return:
  * For other inodes, search forward from the parent directory\'s block
  * group to find a free inode.
  */
-static int find_group_dir(struct super_block *sb, struct inode *parent)
+static ext4_group_t find_group_dir(struct super_block *sb, struct inode *parent)
 {
-	int ngroups = EXT4_SB(sb)->s_groups_count;
+	ext4_group_t ngroups = EXT4_SB(sb)->s_groups_count;
 	unsigned int freei, avefreei;
 	struct ext4_group_desc *desc, *best_desc = NULL;
-	int group, best_group = -1;
+	ext4_group_t group, best_group = -1;
 
 	freei = percpu_counter_read_positive(&EXT4_SB(sb)->s_freeinodes_counter);
 	avefreei = freei / ngroups;
@@ -314,12 +314,13 @@ static int find_group_dir(struct super_block *sb, struct inode *parent)
 #define INODE_COST 64
 #define BLOCK_COST 256
 
-static int find_group_orlov(struct super_block *sb, struct inode *parent)
+static ext4_group_t find_group_orlov(struct super_block *sb,
+				      struct inode *parent)
 {
-	int parent_group = EXT4_I(parent)->i_block_group;
+	ext4_group_t parent_group = EXT4_I(parent)->i_block_group;
 	struct ext4_sb_info *sbi = EXT4_SB(sb);
 	struct ext4_super_block *es = sbi->s_es;
-	int ngroups = sbi->s_groups_count;
+	ext4_group_t ngroups = sbi->s_groups_count;
 	int inodes_per_group = EXT4_INODES_PER_GROUP(sb);
 	unsigned int freei, avefreei;
 	ext4_fsblk_t freeb, avefreeb;
@@ -327,7 +328,7 @@ static int find_group_orlov(struct super_block *sb, struct inode *parent)
 	unsigned int ndirs;
 	int max_debt, max_dirs, min_inodes;
 	ext4_grpblk_t min_blocks;
-	int group = -1, i;
+	ext4_group_t group = -1, i;
 	struct ext4_group_desc *desc;
 
 	freei = percpu_counter_read_positive(&sbi->s_freeinodes_counter);
@@ -340,7 +341,7 @@ static int find_group_orlov(struct super_block *sb, struct inode *parent)
 	if ((parent == sb->s_root->d_inode) ||
 	    (EXT4_I(parent)->i_flags & EXT4_TOPDIR_FL)) {
 		int best_ndir = inodes_per_group;
-		int best_group = -1;
+		ext4_group_t best_group = -1;
 
 		get_random_bytes(&group, sizeof(group));
 		parent_group = (unsigned)group % ngroups;
@@ -415,12 +416,13 @@ fallback:
 	return -1;
 }
 
-static int find_group_other(struct super_block *sb, struct inode *parent)
+static ext4_group_t find_group_other(struct super_block *sb,
+					struct inode *parent)
 {
-	int parent_group = EXT4_I(parent)->i_block_group;
-	int ngroups = EXT4_SB(sb)->s_groups_count;
+	ext4_group_t parent_group = EXT4_I(parent)->i_block_group;
+	ext4_group_t ngroups = EXT4_SB(sb)->s_groups_count;
 	struct ext4_group_desc *desc;
-	int group, i;
+	ext4_group_t group, i;
 
 	/*
 	 * Try to place the inode in its parent directory
@@ -487,7 +489,7 @@ struct inode *ext4_new_inode(handle_t *handle, struct inode * dir, int mode)
 	struct super_block *sb;
 	struct buffer_head *bitmap_bh = NULL;
 	struct buffer_head *bh2;
-	int group;
+	ext4_group_t group;
 	unsigned long ino = 0;
 	struct inode * inode;
 	struct ext4_group_desc * gdp = NULL;
@@ -583,7 +585,7 @@ got:
 	    ino > EXT4_INODES_PER_GROUP(sb)) {
 		ext4_error(sb, __FUNCTION__,
 			   "reserved inode or inode > inodes count - "
-			   "block_group = %d, inode=%lu", group,
+			   "block_group = %lu, inode=%lu", group,
 			   ino + group * EXT4_INODES_PER_GROUP(sb));
 		err = -EIO;
 		goto fail;
@@ -777,7 +779,7 @@ fail_drop:
 struct inode *ext4_orphan_get(struct super_block *sb, unsigned long ino)
 {
 	unsigned long max_ino = le32_to_cpu(EXT4_SB(sb)->s_es->s_inodes_count);
-	unsigned long block_group;
+	ext4_group_t block_group;
 	int bit;
 	struct buffer_head *bitmap_bh = NULL;
 	struct inode *inode = NULL;
@@ -833,7 +835,7 @@ unsigned long ext4_count_free_inodes (struct super_block * sb)
 {
 	unsigned long desc_count;
 	struct ext4_group_desc *gdp;
-	int i;
+	ext4_group_t i;
 #ifdef EXT4FS_DEBUG
 	struct ext4_super_block *es;
 	unsigned long bitmap_count, x;
@@ -879,7 +881,7 @@ unsigned long ext4_count_free_inodes (struct super_block * sb)
 unsigned long ext4_count_dirs (struct super_block * sb)
 {
 	unsigned long count = 0;
-	int i;
+	ext4_group_t i;
 
 	for (i = 0; i < EXT4_SB(sb)->s_groups_count; i++) {
 		struct ext4_group_desc *gdp = ext4_get_group_desc (sb, i, NULL);