git: sys/vfs/hammer: Use bitwise OR to generate ondisk localization

[Tomohiro Kusumi]

commit 7e52af608f079f188f697efc1c0effd28763aff9
Author: Tomohiro Kusumi <kusumi.tomohiro at gmail.com>
Date:   Sat Dec 5 16:32:38 2015 +0900

    sys/vfs/hammer: Use bitwise OR to generate ondisk localization
    
    Use |= to generate localization field for B-Tree elements and
    cursor keys instead of +=, since lower 16 bits are bitfields
    (or safer to treat INODE=0x1 and MISC=0x2 as bitfields).
    
    The typical code to generate ondisk localization value is to
    do either of the followings.
    
      ondisk_lo = local_variable          + {INODE or MISC};
      ondisk_lo = ip->obj_localization    + {INODE or MISC};
      ondisk_lo = HAMMER_XXX_LOCALIZATION + {INODE or MISC};
                  ^^^^^^^^^^^^^^^^^^^^^^^   ^^^^^^^^^^^^^^^
                  (A)32 bits localization   (B)lower 16 bits
                     with usually 0 for
                     lower 16 bits for type
    
    Adding (A) and (B) to synthesize PFS id and localization type
    could lead to a potential bug if (A) already has type bits set
    to either INODE or MISC. For example if (A) had INODE for type
    bits and the code is to += INODE for (B), then type bits turn
    into MISC (1+1=2) which is not the intention of the code.
    
    This could potentially occur with the first example of above
    three where (A) is a local variable or a function argument.
    It is not too obvious from the code whether that local variable
    has 0 for the lower 16 bits (which basically should be).
    If the code just always uses |= no such thing will happen.

Summary of changes:
 sbin/newfs_hammer/newfs_hammer.c  |  4 ++--
 sys/vfs/hammer/hammer.h           |  4 ++--
 sys/vfs/hammer/hammer_btree.h     | 11 ++++++++---
 sys/vfs/hammer/hammer_inode.c     | 14 +++++++-------
 sys/vfs/hammer/hammer_ioctl.c     | 22 +++++++++++-----------
 sys/vfs/hammer/hammer_mirror.c    | 18 +++++++++---------
 sys/vfs/hammer/hammer_object.c    | 10 +++++-----
 sys/vfs/hammer/hammer_pfs.c       |  6 +++---
 sys/vfs/hammer/hammer_prune.c     |  4 ++--
 sys/vfs/hammer/hammer_rebalance.c |  6 +++---
 sys/vfs/hammer/hammer_reblock.c   |  6 +++---
 sys/vfs/hammer/hammer_vfsops.c    |  2 +-
 sys/vfs/hammer/hammer_vnops.c     | 16 ++++++++--------
 13 files changed, 64 insertions(+), 59 deletions(-)

http://gitweb.dragonflybsd.org/dragonfly.git/commitdiff/7e52af608f079f188f697efc1c0effd28763aff9


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