Commit 18db4b4e authored by Theodore Ts'o's avatar Theodore Ts'o
Browse files

ext4: don't allow r/w mounts if metadata blocks overlap the superblock 



If some metadata block, such as an allocation bitmap, overlaps the
superblock, it's very likely that if the file system is mounted
read/write, the results will not be pretty.  So disallow r/w mounts
for file systems corrupted in this particular way.

Signed-off-by: default avatarTheodore Ts'o <tytso@mit.edu>
Cc: stable@vger.kernel.org
parent a45403b5

fs/ext4/super.c

+6 −0
Original line number Diff line number Diff line
@@ -2335,6 +2335,8 @@ static int ext4_check_descriptors(struct super_block *sb, 
			ext4_msg(sb, KERN_ERR, "ext4_check_descriptors: "

				 "Block bitmap for group %u overlaps "

				 "superblock", i);

			if (!sb_rdonly(sb))

				return 0;

		}

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

			ext4_msg(sb, KERN_ERR, "ext4_check_descriptors: "
@@ -2347,6 +2349,8 @@ static int ext4_check_descriptors(struct super_block *sb, 
			ext4_msg(sb, KERN_ERR, "ext4_check_descriptors: "

				 "Inode bitmap for group %u overlaps "

				 "superblock", i);

			if (!sb_rdonly(sb))

				return 0;

		}

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

			ext4_msg(sb, KERN_ERR, "ext4_check_descriptors: "
@@ -2359,6 +2363,8 @@ static int ext4_check_descriptors(struct super_block *sb, 
			ext4_msg(sb, KERN_ERR, "ext4_check_descriptors: "

				 "Inode table for group %u overlaps "

				 "superblock", i);

			if (!sb_rdonly(sb))

				return 0;

		}

		if (inode_table < first_block ||

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