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Diffstat (limited to 'sysdeps/posix/posix_fallocate.c')
-rw-r--r--sysdeps/posix/posix_fallocate.c43
1 files changed, 33 insertions, 10 deletions
diff --git a/sysdeps/posix/posix_fallocate.c b/sysdeps/posix/posix_fallocate.c
index 838e7a0..cbaeb49 100644
--- a/sysdeps/posix/posix_fallocate.c
+++ b/sysdeps/posix/posix_fallocate.c
@@ -1,4 +1,4 @@
-/* Copyright (C) 2000, 2003 Free Software Foundation, Inc.
+/* Copyright (C) 2000, 2003, 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_fallocate (int fd, __off_t offset, __off_t len)
{
struct stat64 st;
struct statfs f;
- size_t step;
- /* `off_tī is a signed type. Therefore we can determine whether
+ /* `off_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_fallocate (int fd, __off_t offset, __off_t len)
if (! S_ISREG (st.st_mode))
return ENODEV;
+ if (len == 0)
+ {
+ if (st.st_size < offset)
+ {
+ int ret = __ftruncate (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 (__fstatfs (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;
+ len -= f.f_bsize;
+
+ if (offset < st.st_size)
+ {
+ unsigned char c;
+ ssize_t rsize = __pread (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 (__pwrite (fd, "", 1, offset) != 1)
return errno;
-
- offset += step;
}
return 0;