Remove sync_file_range()

After hearing horror stories from a trusted colleague, I don't think
this is the kind of API we want to be supporting. Also SQLite wisdom
regarding fdatasync() has been added to the documentation.

Author: jart

libc/calls/calls.h

@@ -201,7 +201,6 @@ int setresuid(unsigned, unsigned, unsigned);
 int getresgid(unsigned *, unsigned *, unsigned *);
 int getresuid(unsigned *, unsigned *, unsigned *);
 char *get_current_dir_name(void) __wur;
-int sync_file_range(int, int64_t, int64_t, unsigned);
 ssize_t splice(int, int64_t *, int, int64_t *, size_t, unsigned);
 int memfd_create(const char *, unsigned int);
 int execvpe(const char *, char *const[], char *const[]);

libc/calls/fdatasync.c

@@ -29,6 +29,11 @@
 /**
  * Blocks until kernel flushes non-metadata buffers for fd to disk.
  *
+ * NOTE: For `IsXnu()` it's recommended that `fcntl(F_FULLFSYNC)` be
+ * favored instead of this function, and if that fails, the fallback
+ * path should call `fsync()` see the SQLite codebase. In the future
+ * Cosmopolitan might do this automatically.
+ *
  * @return 0 on success, or -1 w/ errno
  * @raise ECANCELED if thread was cancelled in masked mode
  * @raise EROFS if `fd` is on a read-only filesystem e.g. /zip
@@ -37,8 +42,8 @@
  * @raise EBADF if `fd` isn't an open file
  * @raise EINTR if signal was delivered
  * @raise EIO if an i/o error happened
- * @see sync(), fsync(), sync_file_range()
  * @see __nosync to secretly disable
+ * @see sync(), fsync()
  * @cancelationpoint
  * @asyncsignalsafe
  */

libc/calls/fsync.c

@@ -37,8 +37,8 @@
  * @raise EBADF if `fd` isn't an open file
  * @raise EINTR if signal was delivered
  * @raise EIO if an i/o error happened
- * @see fdatasync(), sync_file_range()
  * @see __nosync to secretly disable
+ * @see fdatasync()
  * @cancelationpoint
  * @asyncsignalsafe
  */

libc/calls/sync_file_range.c

@@ -108,7 +108,6 @@ i32 sys_sigaction(i32, const void *, void *, i64, i64);
 i32 sys_sigaltstack(const void *, void *);
 i32 sys_symlinkat(const char *, i32, const char *);
 i32 sys_sync(void);
-i32 sys_sync_file_range(i32, i64, i64, u32);
 i32 sys_syncfs(i32);
 i32 sys_syslog(i32, char *, i32);
 i32 sys_tgkill(i32, i32, i32);

libc/calls/syscall-sysv.internal.h

@@ -35,6 +35,7 @@
 #include "libc/errno.h"
 #include "libc/fmt/itoa.h"
 #include "libc/intrin/bits.h"
+#include "libc/intrin/kprintf.h"
 #include "libc/intrin/strace.internal.h"
 #include "libc/limits.h"
 #include "libc/nt/dll.h"

libc/dlopen/dlopen.c

@@ -1461,10 +1461,6 @@ syscon	misc	EFD_CLOEXEC				0x080000		0x080000		0			0			0			0			0			0
 syscon	misc	EFD_NONBLOCK				0x0800			0x0800			0			0			0			0			0			0
 syscon	misc	EFD_SEMAPHORE				1			1			0			0			0			0			0			0
 
-syscon	misc	SYNC_FILE_RANGE_WAIT_AFTER		4			4			0			0			0			0			0			0
-syscon	misc	SYNC_FILE_RANGE_WAIT_BEFORE		1			1			0			0			0			0			0			0
-syscon	misc	SYNC_FILE_RANGE_WRITE			2			2			0			0			0			0			0			0
-
 syscon	misc	TEST_UNIT_READY				0			0			0			0			0			0			0			0
 syscon	misc	TFD_CLOEXEC				0x080000		0x080000		0			0			0			0			0			0
 syscon	misc	TFD_NONBLOCK				0x0800			0x0800			0			0			0			0			0			0
@@ -1807,7 +1803,6 @@ syscon	nr	__NR_faccessat				0x010d			0x0030			0x20001d2		0x01d2			0x01e9			0x013
 syscon	nr	__NR_unshare				0x0110			0x0061			0xfff			0xfff			0xfff			0xfff			0xfff			0xfff
 syscon	nr	__NR_splice				0x0113			0x004c			0xfff			0xfff			0xfff			0xfff			0xfff			0xfff
 syscon	nr	__NR_tee				0x0114			0x004d			0xfff			0xfff			0xfff			0xfff			0xfff			0xfff
-syscon	nr	__NR_sync_file_range			0x0115			0x0054			0xfff			0xfff			0xfff			0xfff			0xfff			0xfff
 syscon	nr	__NR_vmsplice				0x0116			0x004b			0xfff			0xfff			0xfff			0xfff			0xfff			0xfff
 syscon	nr	__NR_migrate_pages			0x0100			0x00ee			0xfff			0xfff			0xfff			0xfff			0xfff			0xfff
 syscon	nr	__NR_move_pages				0x0117			0x00ef			0xfff			0xfff			0xfff			0xfff			0xfff			0xfff