File 0535-Change-efile_allocate-in-Linux-to-change-file-size.patch of Package erlang

From 49395ed9c10dfa8b4583d688e088994cc49d2e98 Mon Sep 17 00:00:00 2001
From: Julius Putra Tanu Setiaji <indocomsoft@gmail.com>
Date: Wed, 2 Oct 2019 10:30:01 +0800
Subject: [PATCH] Change efile_allocate in Linux to change file size

Skip allocate_file_size test if allocate is not supported
---
 erts/emulator/nifs/unix/unix_prim_file.c |  2 +-
 lib/kernel/doc/src/file.xml              |  5 +----
 lib/kernel/test/file_SUITE.erl           | 31 ++++++++++++++++++++-----------
 3 files changed, 22 insertions(+), 16 deletions(-)

diff --git a/erts/emulator/nifs/unix/unix_prim_file.c b/erts/emulator/nifs/unix/unix_prim_file.c
index e5099dd921..e6ddaa3479 100644
--- a/erts/emulator/nifs/unix/unix_prim_file.c
+++ b/erts/emulator/nifs/unix/unix_prim_file.c
@@ -562,7 +562,7 @@ int efile_allocate(efile_data_t *d, Sint64 offset, Sint64 length) {
 #if defined(HAVE_FALLOCATE)
     /* Linux-specific */
     do {
-        ret = fallocate(u->fd, FALLOC_FL_KEEP_SIZE, offset, length);
+        ret = fallocate(u->fd, 0, offset, length);
     } while(ret < 0 && errno == EINTR);
 #elif defined(F_PREALLOCATE)
     /* Mac-specific */
diff --git a/lib/kernel/doc/src/file.xml b/lib/kernel/doc/src/file.xml
index 2c09c84b25..c4073f13a2 100644
--- a/lib/kernel/doc/src/file.xml
+++ b/lib/kernel/doc/src/file.xml
@@ -202,10 +202,7 @@
       <desc>
         <p><c>allocate/3</c> can be used to preallocate space for a file.</p>
         <p>This function only succeeds in platforms that provide this
-          feature. When it succeeds, space is preallocated for the file but
-          the file size might not be updated. This behaviour depends on the
-          preallocation implementation. To guarantee that the file size is updated,
-          truncate the file to the new size.</p>
+          feature.</p>
       </desc>
     </func>
     <func>
diff --git a/lib/kernel/test/file_SUITE.erl b/lib/kernel/test/file_SUITE.erl
index e4299cd346..f432eec708 100644
--- a/lib/kernel/test/file_SUITE.erl
+++ b/lib/kernel/test/file_SUITE.erl
@@ -2233,24 +2233,33 @@ allocate_and_assert(Fd, Offset, Length) ->
 allocate_file_size(Config) when is_list(Config) ->
     case os:type() of
         {unix, darwin} ->
-            PrivDir = proplists:get_value(priv_dir, Config),
-            Allocate = filename:join(PrivDir, atom_to_list(?MODULE)++"_allocate_file"),
-
-            {ok, Fd} = ?FILE_MODULE:open(Allocate, [write]),
-            ok = ?FILE_MODULE:allocate(Fd, 0, 1024),
-            {ok, 1024} = ?FILE_MODULE:position(Fd, eof),
-            ok = ?FILE_MODULE:close(Fd),
-
-            [] = flush(),
-            ok;
+            do_allocate_file_size(Config);
         {unix, linux} ->
-            {skip, "file:allocate/3 on Linux does not change file size"};
+            do_allocate_file_size(Config);
         {win32, _} ->
             {skip, "Windows does not support file:allocate/3"};
         _ ->
             {skip, "Support for allocate/3 is spotty in our test platform at the moment."}
     end.
 
+do_allocate_file_size(Config) when is_list(Config) ->
+    PrivDir = proplists:get_value(priv_dir, Config),
+    Allocate = filename:join(PrivDir, atom_to_list(?MODULE)++"_allocate_file"),
+
+    {ok, Fd} = ?FILE_MODULE:open(Allocate, [write]),
+    Result =
+        case ?FILE_MODULE:allocate(Fd, 0, 1024) of
+            ok ->
+                {ok, 1024} = ?FILE_MODULE:position(Fd, eof),
+                ok;
+            {error, enotsup} ->
+                {skip, "Filesystem does not support file:allocate/3"}
+          end,
+    ok = ?FILE_MODULE:close(Fd),
+
+    [] = flush(),
+    Result.
+
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 
 delete(Config) when is_list(Config) ->
-- 
2.16.4