This is done to match the type of the LSN struct members in layout.h.
The effect of this change is that while these members were declared with
the le64 type previously, leLSN resolves to sle64. I.e. what was
previously unsigned fields are now signed.
Following this change we also need to switch over a few macros from
unsigned to signed versions in the code that uses these struct
definitions.
Strict checking of endian-specific types mean that types that have a
fixed endianness in the data representation of the value are now defined
as complex types, enabling the compiler to catch mixed usage of these
types with native-endian types. This allows us to catch most issues
relating to usage on big-endian systems since we cannot anymore assign a
fixed-endian value to a native-endian variable and vice-versa without a
compiler error.
The downside is that we aren't able to apply simple binary operators to
the fixed-endian types anymore since they are complex... so all
combining fixed-endian constants and values with |, &, etc. and
comparison with ==, !=, <=, etc. must be replaced with a macro which
unpacks the wrapped value and performs the operation. Lots of changes,
lots of work but in the interest of good code quality it's justified.
There were multiple cases of little-endian fields being used as
CPU-endian without byte swapping. This would result in incorrect
behaviour on big-endian systems.
On big-endian systems the result of the '!=' operation would be
endian-swapped rather than the first argument (which must have been the
intended action).
This is harmless except when we do strict endianness checking, in which
case this results in a compile error. Fixed by converting values to
CPU endianness before comparing them.
In 'dump_resident_attr_val', 'i' was sometimes used as a native-endian
'int'-precision string length value and sometimes used as a little-
endian 16-bit flags value. This type of mixed usage is bad practice and
results in a hard error when strict endianness checking is used.
Fixed by introducing new variable 'flags' to hold the little-endian 16-
bit flags value.
If the attribute type is specified by the user, 'attr_type' was assigned
a CPU-endian value, however if the attribute type was not specified it
would be assigned the attribute type AT_DATA, which is a little-endian
value. The rest of the code seems to assume that 'attr_type' is
CPU-endian, so this is clearly a bug.
Resolved by fixing the endianness of the variable at little-endian,
converting the input value to little-endian when specified.
In 'dump_attr_record' the variable 'u' was first used to store a
CPU-endian 32-bit value, and then to store a 16-bit little-endian value.
This is bad practice and results in a hard error when strict endian type
checking is used.
Fixed by storing the 16-bit little-endian flags value in a new variable
'flags'.
This commit addresses issues where little-endian variables are emitted
raw to a log or output stream which is to be interpreted by the user.
Outputting data in non-native endianness can cause confusion for anybody
attempting to debug issues with a file system.
Erik Larsson