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Commit 77260807 authored by Theodore Ts'o's avatar Theodore Ts'o
Browse files

ext4: make sure bitmaps and the inode table don't overlap with bg descriptors 

It's really bad when the allocation bitmaps and the inode table
overlap with the block group descriptors, since it causes random
corruption of the bg descriptors.  So we really want to head those off
at the pass.

https://bugzilla.kernel.org/show_bug.cgi?id=199865



Signed-off-by: default avatarTheodore Ts'o <tytso@mit.edu>
Cc: stable@kernel.org
parent 819b23f1

fs/ext4/super.c

+25 −0
Original line number Diff line number Diff line
@@ -2348,6 +2348,7 @@ static int ext4_check_descriptors(struct super_block *sb, 
	struct ext4_sb_info *sbi = EXT4_SB(sb);

	ext4_fsblk_t first_block = le32_to_cpu(sbi->s_es->s_first_data_block);

	ext4_fsblk_t last_block;

	ext4_fsblk_t last_bg_block = sb_block + ext4_bg_num_gdb(sb, 0) + 1;

	ext4_fsblk_t block_bitmap;

	ext4_fsblk_t inode_bitmap;

	ext4_fsblk_t inode_table;
@@ -2380,6 +2381,14 @@ static int ext4_check_descriptors(struct super_block *sb, 
			if (!sb_rdonly(sb))

				return 0;

		}

		if (block_bitmap >= sb_block + 1 &&

		    block_bitmap <= last_bg_block) {

			ext4_msg(sb, KERN_ERR, "ext4_check_descriptors: "

				 "Block bitmap for group %u overlaps "

				 "block group descriptors", i);

			if (!sb_rdonly(sb))

				return 0;

		}

		if (block_bitmap < first_block || block_bitmap > last_block) {

			ext4_msg(sb, KERN_ERR, "ext4_check_descriptors: "

			       "Block bitmap for group %u not in group "
@@ -2394,6 +2403,14 @@ static int ext4_check_descriptors(struct super_block *sb, 
			if (!sb_rdonly(sb))

				return 0;

		}

		if (inode_bitmap >= sb_block + 1 &&

		    inode_bitmap <= last_bg_block) {

			ext4_msg(sb, KERN_ERR, "ext4_check_descriptors: "

				 "Inode bitmap for group %u overlaps "

				 "block group descriptors", i);

			if (!sb_rdonly(sb))

				return 0;

		}

		if (inode_bitmap < first_block || inode_bitmap > last_block) {

			ext4_msg(sb, KERN_ERR, "ext4_check_descriptors: "

			       "Inode bitmap for group %u not in group "
@@ -2408,6 +2425,14 @@ static int ext4_check_descriptors(struct super_block *sb, 
			if (!sb_rdonly(sb))

				return 0;

		}

		if (inode_table >= sb_block + 1 &&

		    inode_table <= last_bg_block) {

			ext4_msg(sb, KERN_ERR, "ext4_check_descriptors: "

				 "Inode table for group %u overlaps "

				 "block group descriptors", i);

			if (!sb_rdonly(sb))

				return 0;

		}

		if (inode_table < first_block ||

		    inode_table + sbi->s_itb_per_group - 1 > last_block) {

			ext4_msg(sb, KERN_ERR, "ext4_check_descriptors: "