From 61ed73cff427206b3a959b18a4877952f566279b Mon Sep 17 00:00:00 2001 From: Stefan Hajnoczi Date: Thu, 21 Aug 2014 13:44:07 +0100 Subject: raw-posix: fix O_DIRECT short reads The following O_DIRECT read from a <512 byte file fails: $ truncate -s 320 test.img $ qemu-io -n -c 'read -P 0 0 512' test.img qemu-io: can't open device test.img: Could not read image for determining its format: Invalid argument Note that qemu-io completes successfully without the -n (O_DIRECT) option. This patch fixes qemu-iotests ./check -nocache -vmdk 059. Cc: qemu-stable@nongnu.org Suggested-by: Kevin Wolf Reported-by: Markus Armbruster Signed-off-by: Stefan Hajnoczi Signed-off-by: Kevin Wolf --- block/raw-posix.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/block/raw-posix.c b/block/raw-posix.c index 5c745b9a18..d737f3a0c5 100644 --- a/block/raw-posix.c +++ b/block/raw-posix.c @@ -747,6 +747,15 @@ static ssize_t handle_aiocb_rw_linear(RawPosixAIOData *aiocb, char *buf) } if (len == -1 && errno == EINTR) { continue; + } else if (len == -1 && errno == EINVAL && + (aiocb->bs->open_flags & BDRV_O_NOCACHE) && + !(aiocb->aio_type & QEMU_AIO_WRITE) && + offset > 0) { + /* O_DIRECT pread() may fail with EINVAL when offset is unaligned + * after a short read. Assume that O_DIRECT short reads only occur + * at EOF. Therefore this is a short read, not an I/O error. + */ + break; } else if (len == -1) { offset = -errno; break; -- cgit v1.2.1