DAOS-16556 client: call fstat() before mmap() to update file status i…

…n kernel (#15244)

Signed-off-by: Lei Huang <lei.huang@intel.com>

src/client/dfuse/pil4dfs/int_dfs.c

@@ -6302,6 +6302,14 @@ new_mmap(void *addr, size_t length, int prot, int flags, int fd, off_t offset)
 
 	atomic_fetch_add_relaxed(&num_mmap, 1);
 
+	if ((fd < FD_FILE_BASE) && (fd_directed >= FD_FILE_BASE) && d_compatible_mode) {
+		/* DAOS-14494: Force the kernel to update the size before mapping. */
+		rc = next_fxstat(1, fd, &stat_buf);
+		if (rc == -1)
+			return MAP_FAILED;
+		return next_mmap(addr, length, prot, flags, fd, offset);
+	}
+
 	addr_ret = next_mmap(addr, length, prot, flags | MAP_ANONYMOUS, -1, offset);
 	if (addr_ret == MAP_FAILED)
 		return MAP_FAILED;
@@ -7086,10 +7094,8 @@ init_myhook(void)
 
 	register_a_hook("libc", "fcntl", (void *)new_fcntl, (long int *)(&libc_fcntl));
 
-	if (d_compatible_mode == false) {
-		register_a_hook("libc", "mmap", (void *)new_mmap, (long int *)(&next_mmap));
-		register_a_hook("libc", "munmap", (void *)new_munmap, (long int *)(&next_munmap));
-	}
+	register_a_hook("libc", "mmap", (void *)new_mmap, (long int *)(&next_mmap));
+	register_a_hook("libc", "munmap", (void *)new_munmap, (long int *)(&next_munmap));
 
 	register_a_hook("libc", "exit", (void *)new_exit, (long int *)(&next_exit));
 	register_a_hook("libc", "dup3", (void *)new_dup3, (long int *)(&libc_dup3));