[PATCH 1/2] ntdll: Implement alloc_size support in NtCreateFile.

[Patrick Hibbs]

Use posix_fallocate to reserve space for files.
Function will print a warning at runtime if posix_fallocate isn't supported.

Wine-Bug: https://bugs.winehq.org/show_bug.cgi?id=52171
Signed-off-by: Patrick Hibbs <hibbsncc1701 at gmail.com>
---
 dlls/ntdll/unix/file.c | 73 ++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 70 insertions(+), 3 deletions(-)

diff --git a/dlls/ntdll/unix/file.c b/dlls/ntdll/unix/file.c
index 51c92df57e3..07204a8553d 100644
--- a/dlls/ntdll/unix/file.c
+++ b/dlls/ntdll/unix/file.c
@@ -3743,6 +3743,10 @@ NTSTATUS WINAPI NtCreateFile( HANDLE *handle, ACCESS_MASK access, OBJECT_ATTRIBU
     char *unix_name;
     BOOL created = FALSE;
     NTSTATUS status;
+    ULONG new_attributes, new_disposition;
+    struct stat st;
+    LARGE_INTEGER remaining_bytes;
+    int perr, unix_handle;
 
     TRACE( "handle=%p access=%08x name=%s objattr=%08x root=%p sec=%p io=%p alloc_size=%p "
            "attr=%08x sharing=%08x disp=%d options=%08x ea=%p.0x%08x\n",
@@ -3753,8 +3757,6 @@ NTSTATUS WINAPI NtCreateFile( HANDLE *handle, ACCESS_MASK access, OBJECT_ATTRIBU
     *handle = 0;
     if (!attr || !attr->ObjectName) return STATUS_INVALID_PARAMETER;
 
-    if (alloc_size) FIXME( "alloc_size not supported\n" );
-
     new_attr = *attr;
     if (options & FILE_OPEN_BY_FILE_ID)
     {
@@ -3781,10 +3783,75 @@ NTSTATUS WINAPI NtCreateFile( HANDLE *handle, ACCESS_MASK access, OBJECT_ATTRIBU
         status = STATUS_SUCCESS;
     }
 
+#ifdef HAVE_POSIX_FALLOCATE
+    /* Windows doesn't care about the requested access permissions
+     * when performing space reservation. (Windows will trim / grow
+     * the reserved space even if a caller requests read-only
+     * access.)
+     *
+     * Windows *does* care about the disposition given and whether
+     * or not an overwrite will actually occur. (Windows will return
+     * STATUS_OBJECT_NAME_NOT_FOUND if disposition is FILE_OVERWRITE
+     * and the file doesn't exist.)
+     *
+     * POSIX cares about the requested permissions all of the time.
+     * We need to make sure that we ask for enough permissions to
+     * perform the disk space reservation. Afterwards reopen the file
+     * with the desired permissions. As this temporary fd isn't going
+     * to be kept anyway, avoid the round trips to the server by doing
+     * the work here. */
+    if (alloc_size && alloc_size->QuadPart > 0 &&
+        disposition != FILE_OPEN &&
+        (created || (disposition != FILE_OVERWRITE ||
+        status != STATUS_OBJECT_NAME_NOT_FOUND)))
+    {
+        remaining_bytes.QuadPart = 0;
+        new_disposition = FILE_OPEN;
+
+        if (created)
+            remaining_bytes.QuadPart = alloc_size->QuadPart;
+        else
+        {
+            if (get_file_info( unix_name, &st, &new_attributes ) == -1)
+                status = errno_to_status( errno );
+            else
+            {
+                if ((S_ISREG(st.st_mode)) && ((st.st_blocks * 512) < alloc_size->QuadPart))
+                    remaining_bytes.QuadPart = (alloc_size->QuadPart - (st.st_blocks * 512));
+            }
+        }
+
+        if (remaining_bytes.QuadPart > 0)
+        {
+            if (created || disposition == FILE_SUPERSEDE || disposition == FILE_OVERWRITE)
+                unix_handle = open( unix_name, O_RDWR | O_CREAT | O_TRUNC | O_DIRECT | O_SYNC, S_IRWXU );
+            else
+                unix_handle = open( unix_name, O_RDWR | O_DIRECT | O_SYNC, S_IRWXU );
+
+            if (unix_handle == -1)
+                status = errno_to_status( errno );
+            else
+            {
+                perr = posix_fallocate( unix_handle, 0, remaining_bytes.QuadPart );
+                if (perr)
+                    status = errno_to_status( perr );
+
+                close( unix_handle );
+            }
+        }
+    }
+    else
+    {
+        new_disposition = disposition;
+    }
+#else
+        WARN_ONCE("Preallocating files is not supported!\n");
+#endif
+
     if (status == STATUS_SUCCESS)
     {
         status = open_unix_file( handle, unix_name, access, &new_attr, attributes,
-                                 sharing, disposition, options, ea_buffer, ea_length );
+                                 sharing, new_disposition, options, ea_buffer, ea_length );
         free( unix_name );
     }
     else WARN( "%s not found (%x)\n", debugstr_us(attr->ObjectName), status );
-- 
2.30.2