If bdrv_truncate() is called, but the requested size is the same as
before, don't call posix_fallocate(), which returns -EINVAL for length
zero and would therefore make bdrv_truncate() fail.
The problem can be triggered by creating a zero-sized raw image with
'falloc' preallocation mode.
Signed-off-by: Kevin Wolf <kw...@redhat.com>
Reviewed-by: Max Reitz <mre...@redhat.com>
Reviewed-by: Eric Blake <ebl...@redhat.com>
---
block/file-posix.c | 14 +++++++++-----
1 file changed, 9 insertions(+), 5 deletions(-)
diff --git a/block/file-posix.c b/block/file-posix.c
index ba14ed9459..6aed5bca0b 100644
--- a/block/file-posix.c
+++ b/block/file-posix.c
@@ -1686,11 +1686,15 @@ static int raw_regular_truncate(int fd, int64_t offset,
PreallocMode prealloc,
* file systems that do not support fallocate(), trying to check if a
* block is allocated before allocating it, so don't do that here.
*/
- result = -posix_fallocate(fd, current_length, offset - current_length);
- if (result != 0) {
- /* posix_fallocate() doesn't set errno. */
- error_setg_errno(errp, -result,
- "Could not preallocate new data");
+ if (offset != current_length) {
+ result = -posix_fallocate(fd, current_length, offset -
current_length);
+ if (result != 0) {
+ /* posix_fallocate() doesn't set errno. */
+ error_setg_errno(errp, -result,
+ "Could not preallocate new data");
+ }
+ } else {
+ result = 0;
}
goto out;
#endif
--
2.13.6
