From 65d21bc73bda6515fd9b4ff5b2e90454f7a0b419 Mon Sep 17 00:00:00 2001 From: Markus Armbruster Date: Mon, 28 Jun 2010 10:25:20 +0200 Subject: [PATCH] raw-posix: Fix test for host CD-ROM raw_pread_aligned() retries up to two times if the block device backs a virtual CD-ROM (a drive with media=cdrom and if=ide, scsi, xen or none). This makes no sense. Whether retrying reads can correct read errors can only depend on what we're reading, not on how the result gets used. We need to check what whether we're reading from a physical CD-ROM or floppy here. I doubt retrying is useful even then. Left for another day. Impact: * Virtual CD-ROM backed by host_cdrom behaves the same. * Virtual CD-ROM backed by file or host_device no longer retries. * A drive backed by host_cdrom now retries even if it's not a virtual CD-ROM. * Any drive backed by host_floppy now retries. While there, clean up gratuitous use of goto. Signed-off-by: Markus Armbruster Signed-off-by: Kevin Wolf --- block/raw-posix.c | 17 ++++++----------- 1 file changed, 6 insertions(+), 11 deletions(-) diff --git a/block/raw-posix.c b/block/raw-posix.c index 3f0701b8a4..291699fbc3 100644 --- a/block/raw-posix.c +++ b/block/raw-posix.c @@ -242,15 +242,14 @@ static int raw_pread_aligned(BlockDriverState *bs, int64_t offset, ret = pread(s->fd, buf, count, offset); if (ret == count) - goto label__raw_read__success; + return ret; /* Allow reads beyond the end (needed for pwrite) */ if ((ret == 0) && bs->growable) { int64_t size = raw_getlength(bs); if (offset >= size) { memset(buf, 0, count); - ret = count; - goto label__raw_read__success; + return count; } } @@ -260,13 +259,13 @@ static int raw_pread_aligned(BlockDriverState *bs, int64_t offset, bs->total_sectors, ret, errno, strerror(errno)); /* Try harder for CDrom. */ - if (bs->type == BDRV_TYPE_CDROM) { + if (s->type != FTYPE_FILE) { ret = pread(s->fd, buf, count, offset); if (ret == count) - goto label__raw_read__success; + return ret; ret = pread(s->fd, buf, count, offset); if (ret == count) - goto label__raw_read__success; + return ret; DEBUG_BLOCK_PRINT("raw_pread(%d:%s, %" PRId64 ", %p, %d) [%" PRId64 "] retry read failed %d : %d = %s\n", @@ -274,8 +273,6 @@ static int raw_pread_aligned(BlockDriverState *bs, int64_t offset, bs->total_sectors, ret, errno, strerror(errno)); } -label__raw_read__success: - return (ret < 0) ? -errno : ret; } @@ -298,15 +295,13 @@ static int raw_pwrite_aligned(BlockDriverState *bs, int64_t offset, ret = pwrite(s->fd, buf, count, offset); if (ret == count) - goto label__raw_write__success; + return ret; DEBUG_BLOCK_PRINT("raw_pwrite(%d:%s, %" PRId64 ", %p, %d) [%" PRId64 "] write failed %d : %d = %s\n", s->fd, bs->filename, offset, buf, count, bs->total_sectors, ret, errno, strerror(errno)); -label__raw_write__success: - return (ret < 0) ? -errno : ret; }