From: Thomas Huth Date: Thu, 27 May 2021 17:20:20 +0000 (+0200) Subject: block/file-posix: Try other fallbacks after invalid FALLOC_FL_ZERO_RANGE X-Git-Tag: v6.1.0-rc0~89^2~11 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=fa95e9fbab2c19fc07ba82988b1690f8a6ff171b;p=thirdparty%2Fqemu.git block/file-posix: Try other fallbacks after invalid FALLOC_FL_ZERO_RANGE If fallocate(... FALLOC_FL_ZERO_RANGE ...) returns EINVAL, it's likely an indication that the file system is buggy and does not implement unaligned accesses right. We still might be lucky with the other fallback fallocate() calls later in this function, though, so we should not return immediately and try the others first. Since FALLOC_FL_ZERO_RANGE could also return EINVAL if the file descriptor is not a regular file, we ignore this filesystem bug silently, without printing an error message for the user. Signed-off-by: Thomas Huth Message-Id: <20210527172020.847617-3-thuth@redhat.com> Signed-off-by: Kevin Wolf --- diff --git a/block/file-posix.c b/block/file-posix.c index 6e24083f3fc..f37dfc10b39 100644 --- a/block/file-posix.c +++ b/block/file-posix.c @@ -1625,17 +1625,17 @@ static int handle_aiocb_write_zeroes(void *opaque) if (s->has_write_zeroes) { int ret = do_fallocate(s->fd, FALLOC_FL_ZERO_RANGE, aiocb->aio_offset, aiocb->aio_nbytes); - if (ret == -EINVAL) { - /* - * Allow falling back to pwrite for file systems that - * do not support fallocate() for an unaligned byte range. - */ - return -ENOTSUP; - } - if (ret == 0 || ret != -ENOTSUP) { + if (ret == -ENOTSUP) { + s->has_write_zeroes = false; + } else if (ret == 0 || ret != -EINVAL) { return ret; } - s->has_write_zeroes = false; + /* + * Note: Some file systems do not like unaligned byte ranges, and + * return EINVAL in such a case, though they should not do it according + * to the man-page of fallocate(). Thus we simply ignore this return + * value and try the other fallbacks instead. + */ } #endif