These are all the ext4 patches that were tagged for -stable and failed to apply to 3.18.y.
Side note: Patch e15dc99dbb9c ("ALSA: pcm: Fix endless loop for XRUN recovery in OSS emulation") which was tagged for -stable is not required on 3.18.y so I have skipped the backport.
Theodore Ts'o (4): ext4: add validity checks for bitmap block numbers ext4: fail ext4_iget for root directory if unallocated ext4: don't allow r/w mounts if metadata blocks overlap the superblock ext4: force revalidation of directory pointer after seekdir(2)
fs/ext4/balloc.c | 16 ++++++++++++++-- fs/ext4/dir.c | 8 +++++--- fs/ext4/ialloc.c | 7 +++++++ fs/ext4/inode.c | 6 ++++++ fs/ext4/super.c | 6 ++++++ 5 files changed, 38 insertions(+), 5 deletions(-)