2005-06-14 Ulrich Drepper <drepper@redhat.com>

	[BZ #1083]
	* sysdeps/posix/posix_fallocate64.c: Use __libc_pread64 instead of
	__pread64.
2005-04-29  Jakub Jelinek  <jakub@redhat.com>

	[BZ #1083]
	* sysdeps/posix/posix_fallocate.c (posix_fallocate): If len == 0,
	call ftruncate if offset is bigger than current size.  Make sure
	the file is offset + len bytes long if that is more than current size.
	Don't overwrite previous content of the file.
	* sysdeps/posix/posix_fallocate64.c (__posix_fallocate64_l64):
	Likewise.

diff --git a/sysdeps/posix/posix_fallocate64.c b/sysdeps/posix/posix_fallocate64.c
index 0eba4161a5c66e737097fb82731ba290f5c0b974..64ca9ae83d49f149ffd9110cd4f161b87c953704 100644 (file)
--- a/sysdeps/posix/posix_fallocate64.c
+++ b/sysdeps/posix/posix_fallocate64.c
@@ -1,4 +1,4 @@
-/* Copyright (C) 2000, 2003, 2004 Free Software Foundation, Inc.
+/* Copyright (C) 2000, 2003, 2004, 2005 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
 
    The GNU C Library is free software; you can redistribute it and/or
@@ -29,9 +29,8 @@ __posix_fallocate64_l64 (int fd, __off64_t offset, __off64_t len)
 {
   struct stat64 st;
   struct statfs64 f;
-  size_t step;
 
-  /* `off64_t´ is a signed type.  Therefore we can determine whether
+  /* `off64_t' is a signed type.  Therefore we can determine whether
      OFFSET + LEN is too large if it is a negative value.  */
   if (offset < 0 || len < 0)
     return EINVAL;
@@ -47,24 +46,48 @@ __posix_fallocate64_l64 (int fd, __off64_t offset, __off64_t len)
   if (! S_ISREG (st.st_mode))
     return ENODEV;
 
+  if (len == 0)
+    {
+      if (st.st_size < offset)
+       {
+         int ret = __ftruncate64 (fd, offset);
+
+         if (ret != 0)
+           ret = errno;
+         return ret;
+       }
+      return 0;
+    }
+
   /* We have to know the block size of the filesystem to get at least some
      sort of performance.  */
   if (__fstatfs64 (fd, &f) != 0)
     return errno;
 
-  /* Align OFFSET to block size and adjust LEN.  */
-  step = (offset + f.f_bsize - 1) % ~f.f_bsize;
-  offset += step;
+  /* Try to play safe.  */
+  if (f.f_bsize == 0)
+    f.f_bsize = 512;
 
   /* Write something to every block.  */
-  while (len > step)
+  for (offset += (len - 1) % f.f_bsize; len > 0; offset += f.f_bsize)
     {
-      len -= step;
-
-      if (__pwrite64 (fd, "", 1, offset) != 1)
+      len -= f.f_bsize;
+
+      if (offset < st.st_size)
+       {
+         unsigned char c;
+         ssize_t rsize = __libc_pread64 (fd, &c, 1, offset);
+
+         if (rsize < 0)
+           return errno;
+         /* If there is a non-zero byte, the block must have been
+            allocated already.  */
+         else if (rsize == 1 && c != 0)
+           continue;
+       }
+
+      if (__libc_pwrite64 (fd, "", 1, offset) != 1)
        return errno;
-
-      offset += step;
     }
 
   return 0;