tree 3a6cbb4a7e6bbb9365c8092541a04d3ea1f77ce6
parent cf6e693212263d33c5882e4653df89a2fca4c0c4
author Jeff Mahoney <jeffm@suse.com> 1256600996 -0700
committer Linus Torvalds <torvalds@linux-foundation.org> 1256827169 -0700

hfs: fix oops on mount with corrupted btree extent records

A particular fsfuzzer run caused an hfs file system to crash on mount.
This is due to a corrupted MDB extent record causing a miscalculation of
HFS_I(inode)->first_blocks for the extent tree.  If the extent records are
zereod out, it won't trigger the first_blocks special case.  Instead it
falls through to the extent code which we're still in the middle of
initializing.

This patch catches the 0 size extent records, reports the corruption, and
fails the mount.

Reported-by: Ramon de Carvalho Valle <rcvalle@linux.vnet.ibm.com>
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Cc: Valdis Kletnieks <Valdis.Kletnieks@vt.edu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>