This moves the Rust sources out of rust_src/ and into the top level.
Running the bcachefs executable out of the development tree is now:
$ ./target/release/bcachefs command
or
$ cargo run --profile release -- command
instead of "./bcachefs command".
Building and installing is still:
$ make && make install
Signed-off-by: Thomas Bertschinger <tahbertschinger@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
bcachefs format on a big-endian (s390x) machine crashes down in the
rhashtable code imported from the kernel. The reason this occurs
lies within the rht_lock() -> bit_spin_lock() code, the latter of
which casts bitmaps down to 32-bits to satisfy the requirements of
the futex interface.
The specific problem here is that a 64 -> 32 bit cast doesn't refer
to the lower 8 bytes on a big endian machine, which means setting
bit number 0 in the 32-bit map actually corresponds to bit 32 in the
64-bit map. The rhashtable code specifically uses bit zero of the
bucket pointer for exclusion and uses native bitops elsewhere (i.e.
__rht_ptr()) to identify NULL pointers. If bit 32 of the pointer is
set by the locking code instead of bit 0, an otherwise NULL pointer
looks like a non-NULL value and results in a segfault.
The bit spinlock code imported by the kernel is originally intended
to work with unsigned long. The kernel code is able to throttle the
cpu directly when under lock contention, while the userspace
implementation relies on the futex primitives to emulate reliable
blocking. Since the futex interface introduces the 32-bit
requirement, isolate the associated userspace hack to that
particular code.
Restore the native bitmap behavior of the bit spinlock code to
address the rhashtable problem described above. Since this is not
compatible with the futex interface, create a futex wrapper
specifically to convert the native bitmap type to a 32-bit virtual
address and mask value for the purposes of waiting/waking when under
lock contention.
Signed-off-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Hi
Here I'm sending a small compile fix for bcachefs-tools.
Without this patch, I get this error:
cargo build --release --manifest-path rust-src/Cargo.toml
Compiling bch_bindgen v0.1.0
(/usr/src/git/bcachefs-tools/rust-src/bch_bindgen)
error: failed to run custom build command for `bch_bindgen v0.1.0
(/usr/src/git/bcachefs-tools/rust-src/bch_bindgen)`
Caused by:
process didn't exit successfully:
`/usr/src/git/bcachefs-tools/rust-src/target/release/build/bch_bindgen-733e88995ce9eab7/build-script-build`
(exit status: 101)
--- stderr
warning: optimization flag '-fkeep-inline-functions' is not supported
[-Wignored-optimization-argument]
../../include/linux/bit_spinlock.h:20:3: error: call to undeclared
function 'futex'; ISO C99 and later do not support implicit function
declarations [-Wimplicit-function-declaration]
../../include/linux/bit_spinlock.h:28:2: error: call to undeclared
function 'futex'; ISO C99 and later do not support implicit function
declarations [-Wimplicit-function-declaration]
../../include/linux/bit_spinlock.h:39:2: error: call to undeclared
function 'futex'; ISO C99 and later do not support implicit function
declarations [-Wimplicit-function-declaration]
The futex() function is declared in
/usr/include/x86_64-linux-gnu/urcu/futex.h
It is not declared in linux/futex.h, so we need to include urcu/futex.h
Mikulas
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
