A generically useful library for finding and managing contiguous areas of disk space. Getting the interface right is non-trivial, but there are a lot of concepts which are independent of on-disk file system layout which could be reused. Good starting points are the ext3 reservation code and/or the XFS extent allocation code (the ext2 preallocation code is NOT a good place to start). Short of that, finish and test the port of the ext3 reservation code to ext2, started here: http://infohost.nmt.edu/~val/patches/resv_only_patch Contact: valh
Some kind of hook into the disk EIO reporting which allows file systems to register a handler which does things like set the "fsck me now" bit. Contact: valh
Simple block bitmap sanity checking for ext2/3/4. When a new block bitmap is read from disk in read_block_bitmap() there are a few bits that should ALWAYS be set for each group. In particular, the blocks given by desc->bg_block_bitmap, desc->bg_inode_bitmap, and {desc->bg_inode_table, +sbi->s_itb_per_group}. If any of those those bits (shifted to be relative to the current group, of course) are not set then the on-disk group descriptor is corrupt, or there is some problem reading it from disk and an ext3_error() should be called (possibly making the filesystem read-only).