1 files changed, 28 insertions, 16 deletions

diff --git a/fs/ext2/super.c b/fs/ext2/super.c
index 73b2d528237f..0128010a0874 100644
--- a/fs/ext2/super.c
+++ b/fs/ext2/super.c
@@ -757,7 +757,8 @@ static loff_t ext2_max_size(int bits)
 {
 	loff_t res = EXT2_NDIR_BLOCKS;
 	int meta_blocks;
-	loff_t upper_limit;
+	unsigned int upper_limit;
+	unsigned int ppb = 1 << (bits-2);
 
 	/* This is calculated to be the largest file size for a
 	 * dense, file such that the total number of
@@ -771,24 +772,34 @@ static loff_t ext2_max_size(int bits)
 	/* total blocks in file system block size */
 	upper_limit >>= (bits - 9);
 
+	/* Compute how many blocks we can address by block tree */
+	res += 1LL << (bits-2);
+	res += 1LL << (2*(bits-2));
+	res += 1LL << (3*(bits-2));
+	/* Does block tree limit file size? */
+	if (res < upper_limit)
+		goto check_lfs;
 
+	res = upper_limit;
+	/* How many metadata blocks are needed for addressing upper_limit? */
+	upper_limit -= EXT2_NDIR_BLOCKS;
 	/* indirect blocks */
 	meta_blocks = 1;
+	upper_limit -= ppb;
 	/* double indirect blocks */
-	meta_blocks += 1 + (1LL << (bits-2));
-	/* tripple indirect blocks */
-	meta_blocks += 1 + (1LL << (bits-2)) + (1LL << (2*(bits-2)));
-
-	upper_limit -= meta_blocks;
-	upper_limit <<= bits;
-
-	res += 1LL << (bits-2);
-	res += 1LL << (2*(bits-2));
-	res += 1LL << (3*(bits-2));
+	if (upper_limit < ppb * ppb) {
+		meta_blocks += 1 + DIV_ROUND_UP(upper_limit, ppb);
+		res -= meta_blocks;
+		goto check_lfs;
+	}
+	meta_blocks += 1 + ppb;
+	upper_limit -= ppb * ppb;
+	/* tripple indirect blocks for the rest */
+	meta_blocks += 1 + DIV_ROUND_UP(upper_limit, ppb) +
+		DIV_ROUND_UP(upper_limit, ppb*ppb);
+	res -= meta_blocks;
+check_lfs:
 	res <<= bits;
-	if (res > upper_limit)
-		res = upper_limit;
-
 	if (res > MAX_LFS_FILESIZE)
 		res = MAX_LFS_FILESIZE;
 
@@ -1024,8 +1035,6 @@ static int ext2_fill_super(struct super_block *sb, void *data, int silent)
 	sbi->s_frags_per_group = le32_to_cpu(es->s_frags_per_group);
 	sbi->s_inodes_per_group = le32_to_cpu(es->s_inodes_per_group);
 
-	if (EXT2_INODE_SIZE(sb) == 0)
-		goto cantfind_ext2;
 	sbi->s_inodes_per_block = sb->s_blocksize / EXT2_INODE_SIZE(sb);
 	if (sbi->s_inodes_per_block == 0 || sbi->s_inodes_per_group == 0)
 		goto cantfind_ext2;
@@ -1087,12 +1096,14 @@ static int ext2_fill_super(struct super_block *sb, void *data, int silent)
 					   sizeof(struct buffer_head *),
 					   GFP_KERNEL);
 	if (sbi->s_group_desc == NULL) {
+		ret = -ENOMEM;
 		ext2_msg(sb, KERN_ERR, "error: not enough memory");
 		goto failed_mount;
 	}
 	bgl_lock_init(sbi->s_blockgroup_lock);
 	sbi->s_debts = kcalloc(sbi->s_groups_count, sizeof(*sbi->s_debts), GFP_KERNEL);
 	if (!sbi->s_debts) {
+		ret = -ENOMEM;
 		ext2_msg(sb, KERN_ERR, "error: not enough memory");
 		goto failed_mount_group_desc;
 	}
@@ -1148,6 +1159,7 @@ static int ext2_fill_super(struct super_block *sb, void *data, int silent)
 #ifdef CONFIG_EXT2_FS_XATTR
 	sbi->s_ea_block_cache = ext2_xattr_create_cache();
 	if (!sbi->s_ea_block_cache) {
+		ret = -ENOMEM;
 		ext2_msg(sb, KERN_ERR, "Failed to create ea_block_cache");
 		goto failed_mount3;
 	}