On Oct 7, 2011, at 10:20 AM, Kasatkin, Dmitry wrote: >> With ext4 the >> time to run pass 1 was significantly reduced. > > Yes... It is really noticeable.. > I assume it is achieved not by compromising check quality... > What is the reason? The use of extents significantly reduces the amount of metadata (specifically indirect blocks/double indirect blocks/triple indirect blocks) which required a lot of seeking during the pass 1 scan. In addition, because we are using checksums to protect the block group descriptors against accidental corruption, we can afford to avoid scanning parts of the inode table which are unused. Of course, we never worried about deliberately malicious attackers; so if you're going to depend on e2fsck's pass1 checks for IMA protection, we would need to add a check in ext4_get_inode_loc() in the kernel to flag the file system as containing an error (and you would have to require remounting the file system read-only in that circumstances) if there was an attempt to read in an inode which exceeds the high watermark of used inodes for the block group. -- Ted -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
