Commit 31d4f3a2 authored Mar 11, 2012 by Theodore Ts'o

ext4: check for zero length extent

Explicitly test for an extent whose length is zero, and flag that as a
corrupted extent.

This avoids a kernel BUG_ON assertion failure.

Tested: Without this patch, the file system image found in
tests/f_ext_zero_len/image.gz in the latest e2fsprogs sources causes a
kernel panic.  With this patch, an ext4 file system error is noted
instead, and the file system is marked as being corrupted.

https://bugzilla.kernel.org/show_bug.cgi?id=42859



Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: stable@kernel.org

parent 4188188b

fs/ext4/extents.c

+2 −0

Original line number	Diff line number	Diff line
		@@ -300,6 +300,8 @@ static int ext4_valid_extent(struct inode inode, struct ext4_extent ext)
		ext4_fsblk_t block = ext4_ext_pblock(ext);
		int len = ext4_ext_get_actual_len(ext);

		if (len == 0)
		return 0;
		return ext4_data_block_valid(EXT4_SB(inode->i_sb), block, len);
		}