MirrorHub/construct
0
0
Fork 0
mirror of https://github.com/matrix-construct/construct synced 2024-12-27 07:54:05 +01:00
Code Issues Releases Wiki Activity

ircd::fs: Runtime binding for pwritev(2)/pwritev2(2) based on kernel version.

Browse source
This commit is contained in:
Jason Volk 2019-04-17 18:12:43 -07:00
parent 6fbf882e16
commit 1eaff2e91e
2 changed files with 67 additions and 13 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

3
include/ircd/fs/fs.h
View file

@ -36,7 +36,8 @@ namespace ircd::fs
// may make forward-declared references to boost symbols.
namespace filesystem = boost::filesystem;
// RWF_ support
// Runtime-detected support lights.
extern const bool support_pwritev2;
extern const bool support_append;
extern const bool support_nowait;
extern const bool support_hipri;

77
ircd/fs.cc
View file

@ -32,6 +32,17 @@ ircd::fs::log
"fs"
};
decltype(ircd::fs::support_pwritev2)
ircd::fs::support_pwritev2
{
#if defined(HAVE_PWRITEV2)
info::kversion[0] >= 4 &&
info::kversion[1] >= 6
#else
false
#endif
};
decltype(ircd::fs::support_sync)
ircd::fs::support_sync
{
@ -934,10 +945,21 @@ ircd::fs::write(const string_view &path,
return write(fd, bufs, opts);
}
// Platform-specific write() implementations.
namespace ircd::fs
{
static int flags(const write_opts &opts);
static size_t _write(const fd &, const const_iovec_view &, const write_opts &);
static size_t _write__pwritev2(const fd &, const const_iovec_view &, const write_opts &);
static size_t _write__pwritev1(const fd &, const const_iovec_view &, const write_opts &);
extern "C" decltype(_write__pwritev1) *ircd_fs_write_pwritev__resolve();
extern size_t
_write_pwritev(const fd &,
const const_iovec_view &,
const write_opts &)
__attribute__((ifunc("ircd_fs_write_pwritev__resolve")));
static size_t write(const fd &, const const_iovec_view &, const write_opts &);
}
@ -998,14 +1020,43 @@ ircd::fs::write(const fd &fd,
return aio::write(fd, iov, opts);
#endif
return _write(fd, iov, opts);
return _write_pwritev(fd, iov, opts);
}
/// This function allows the linker to dynamically resolve the internal _write()
/// definition we'll be using during this execution. We check for the pwritev2
/// support flag which was initialized based on the kernel version.
extern "C" decltype(ircd::fs::_write__pwritev1) *
ircd::fs::ircd_fs_write_pwritev__resolve()
{
log::logf
{
log, support_pwritev2? log::DEBUG : log::DWARNING,
"This host '%s %s' %s the pwritev2(2) system call.",
info::kname,
info::kversion_str,
support_pwritev2? "SUPPORTS"_sv : "DOES NOT SUPPORT"_sv
};
return support_pwritev2? _write__pwritev2 : _write__pwritev1;
}
size_t
ircd::fs::_write__pwritev1(const fd &fd,
const const_iovec_view &iov,
const write_opts &opts)
{
return
opts.interruptible?
syscall(::pwritev, fd, iov.data(), iov.size(), opts.offset):
syscall_nointr(::pwritev, fd, iov.data(), iov.size(), opts.offset);
}
#ifdef HAVE_PWRITEV2
size_t
ircd::fs::_write(const fd &fd,
const const_iovec_view &iov,
const write_opts &opts)
ircd::fs::_write__pwritev2(const fd &fd,
const const_iovec_view &iov,
const write_opts &opts)
{
// Manpages sez that when appending with RWF_APPEND, the offset has no
// effect on the write; but if the value of the offset is -1 then the
@ -1027,14 +1078,16 @@ ircd::fs::_write(const fd &fd,
}
#else
size_t
ircd::fs::_write(const fd &fd,
const const_iovec_view &iov,
const write_opts &opts)
[[noreturn]]
ircd::fs::_write__pwritev2(const fd &fd,
const const_iovec_view &iov,
const write_opts &opts)
{
return
opts.interruptible?
syscall(::pwritev, fd, iov.data(), iov.size(), opts.offset):
syscall_nointr(::pwritev, fd, iov.data(), iov.size(), opts.offset);
ircd::terminate(panic
{
"This build does not support pwritev2()."
" This function should not have been selected."
});
}
#endif