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2024-02-20 102a0743326a03cd1a1202ceda21e175b7d3575c

 kernel/fs/ext4/balloc.c
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@@ -303,6 +303,36 @@
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 	return desc;
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 }
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+static ext4_fsblk_t ext4_valid_block_bitmap_padding(struct super_block *sb,
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+						    ext4_group_t block_group,
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+						    struct buffer_head *bh)
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+{
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+	ext4_grpblk_t next_zero_bit;
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+	unsigned long bitmap_size = sb->s_blocksize * 8;
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+	unsigned int offset = num_clusters_in_group(sb, block_group);
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+
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+	if (bitmap_size <= offset)
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+		return 0;
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+
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+	next_zero_bit = ext4_find_next_zero_bit(bh->b_data, bitmap_size, offset);
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+
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+	return (next_zero_bit < bitmap_size ? next_zero_bit : 0);
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+}
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+
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+struct ext4_group_info *ext4_get_group_info(struct super_block *sb,
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+					    ext4_group_t group)
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+{
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+	struct ext4_group_info **grp_info;
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+	long indexv, indexh;
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+
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+	if (unlikely(group >= EXT4_SB(sb)->s_groups_count))
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+		return NULL;
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+	indexv = group >> (EXT4_DESC_PER_BLOCK_BITS(sb));
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+	indexh = group & ((EXT4_DESC_PER_BLOCK(sb)) - 1);
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+	grp_info = sbi_array_rcu_deref(EXT4_SB(sb), s_group_info, indexv);
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+	return grp_info[indexh];
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+}
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+
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 /*
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  * Return the block number which was discovered to be invalid, or 0 if
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  * the block bitmap is valid.
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@@ -377,7 +407,7 @@
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 	if (buffer_verified(bh))
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 		return 0;
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-	if (EXT4_MB_GRP_BBITMAP_CORRUPT(grp))
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+	if (!grp || EXT4_MB_GRP_BBITMAP_CORRUPT(grp))
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 		return -EFSCORRUPTED;
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 	ext4_lock_group(sb, block_group);
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@@ -399,6 +429,15 @@
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 			   block_group, blk);
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 		ext4_mark_group_bitmap_corrupted(sb, block_group,
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 					EXT4_GROUP_INFO_BBITMAP_CORRUPT);
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+		return -EFSCORRUPTED;
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+	}
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+	blk = ext4_valid_block_bitmap_padding(sb, block_group, bh);
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+	if (unlikely(blk != 0)) {
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+		ext4_unlock_group(sb, block_group);
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+		ext4_error(sb, "bg %u: block %llu: padding at end of block bitmap is not set",
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+			   block_group, blk);
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+		ext4_mark_group_bitmap_corrupted(sb, block_group,
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+						 EXT4_GROUP_INFO_BBITMAP_CORRUPT);
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 		return -EFSCORRUPTED;
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 	}
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 	set_buffer_verified(bh);
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@@ -864,11 +903,11 @@
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 }
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 /*
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- * This function returns the number of file system metadata clusters at
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+ * This function returns the number of file system metadata blocks at
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  * the beginning of a block group, including the reserved gdt blocks.
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  */
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-static unsigned ext4_num_base_meta_clusters(struct super_block *sb,
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-				     ext4_group_t block_group)
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+unsigned int ext4_num_base_meta_blocks(struct super_block *sb,
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+				       ext4_group_t block_group)
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 {
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 	struct ext4_sb_info *sbi = EXT4_SB(sb);
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 	unsigned num;
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@@ -886,8 +925,15 @@
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 	} else { /* For META_BG_BLOCK_GROUPS */
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 		num += ext4_bg_num_gdb(sb, block_group);
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 	}
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-	return EXT4_NUM_B2C(sbi, num);
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+	return num;
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 }
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+
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+static unsigned int ext4_num_base_meta_clusters(struct super_block *sb,
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+						ext4_group_t block_group)
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+{
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+	return EXT4_NUM_B2C(EXT4_SB(sb), ext4_num_base_meta_blocks(sb, block_group));
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+}
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+
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 /**
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  *	ext4_inode_to_goal_block - return a hint for block allocation
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  *	@inode: inode for block allocation