From 8b33d9eeba91422ee2d73b6936ad57262d18cf5a Mon Sep 17 00:00:00 2001 From: Anthony Liguori Date: Wed, 8 Sep 2010 17:09:15 -0500 Subject: [PATCH] Revert "Make default invocation of block drivers safer (v3)" This reverts commit 79368c81bf8cf93864d7afc88b81b05d8f0a2c90. Conflicts: block.c I haven't been able to come up with a solution yet for the corruption caused by unaligned requests from the IDE disk so revert until a solution can be written. Signed-off-by: Anthony Liguori --- block.c | 4 -- block/raw.c | 130 ---------------------------------------------------- block_int.h | 1 - 3 files changed, 135 deletions(-) diff --git a/block.c b/block.c index a5514e361a..66bba875dd 100644 --- a/block.c +++ b/block.c @@ -523,7 +523,6 @@ int bdrv_open(BlockDriverState *bs, const char *filename, int flags, BlockDriver *drv) { int ret; - int probed = 0; if (flags & BDRV_O_SNAPSHOT) { BlockDriverState *bs1; @@ -584,7 +583,6 @@ int bdrv_open(BlockDriverState *bs, const char *filename, int flags, /* Find the right image format driver */ if (!drv) { ret = find_image_format(filename, &drv); - probed = 1; } if (!drv) { @@ -597,8 +595,6 @@ int bdrv_open(BlockDriverState *bs, const char *filename, int flags, goto unlink_and_fail; } - bs->probed = probed; - /* If there is a backing file, use it */ if ((flags & BDRV_O_NO_BACKING) == 0 && bs->backing_file[0] != '\0') { char backing_filename[PATH_MAX]; diff --git a/block/raw.c b/block/raw.c index 61e674856d..91087792fc 100644 --- a/block/raw.c +++ b/block/raw.c @@ -9,82 +9,15 @@ static int raw_open(BlockDriverState *bs, int flags) return 0; } -/* check for the user attempting to write something that looks like a - block format header to the beginning of the image and fail out. -*/ -static int check_for_block_signature(BlockDriverState *bs, const uint8_t *buf) -{ - static const uint8_t signatures[][4] = { - { 'Q', 'F', 'I', 0xfb }, /* qcow/qcow2 */ - { 'C', 'O', 'W', 'D' }, /* VMDK3 */ - { 'V', 'M', 'D', 'K' }, /* VMDK4 */ - { 'O', 'O', 'O', 'M' }, /* UML COW */ - {} - }; - int i; - - for (i = 0; signatures[i][0] != 0; i++) { - if (memcmp(buf, signatures[i], 4) == 0) { - return 1; - } - } - - return 0; -} - -static int check_write_unsafe(BlockDriverState *bs, int64_t sector_num, - const uint8_t *buf, int nb_sectors) -{ - /* assume that if the user specifies the format explicitly, then assume - that they will continue to do so and provide no safety net */ - if (!bs->probed) { - return 0; - } - - if (sector_num == 0 && nb_sectors > 0) { - return check_for_block_signature(bs, buf); - } - - return 0; -} - static int raw_read(BlockDriverState *bs, int64_t sector_num, uint8_t *buf, int nb_sectors) { return bdrv_read(bs->file, sector_num, buf, nb_sectors); } -static int raw_write_scrubbed_bootsect(BlockDriverState *bs, - const uint8_t *buf) -{ - uint8_t bootsect[512]; - - /* scrub the dangerous signature */ - memcpy(bootsect, buf, 512); - memset(bootsect, 0, 4); - - return bdrv_write(bs->file, 0, bootsect, 1); -} - static int raw_write(BlockDriverState *bs, int64_t sector_num, const uint8_t *buf, int nb_sectors) { - if (check_write_unsafe(bs, sector_num, buf, nb_sectors)) { - int ret; - - ret = raw_write_scrubbed_bootsect(bs, buf); - if (ret < 0) { - return ret; - } - - ret = bdrv_write(bs->file, 1, buf + 512, nb_sectors - 1); - if (ret < 0) { - return ret; - } - - return ret + 512; - } - return bdrv_write(bs->file, sector_num, buf, nb_sectors); } @@ -95,73 +28,10 @@ static BlockDriverAIOCB *raw_aio_readv(BlockDriverState *bs, return bdrv_aio_readv(bs->file, sector_num, qiov, nb_sectors, cb, opaque); } -typedef struct RawScrubberBounce -{ - BlockDriverCompletionFunc *cb; - void *opaque; - QEMUIOVector qiov; -} RawScrubberBounce; - -static void raw_aio_writev_scrubbed(void *opaque, int ret) -{ - RawScrubberBounce *b = opaque; - - if (ret < 0) { - b->cb(b->opaque, ret); - } else { - b->cb(b->opaque, ret + 512); - } - - qemu_iovec_destroy(&b->qiov); - qemu_free(b); -} - static BlockDriverAIOCB *raw_aio_writev(BlockDriverState *bs, int64_t sector_num, QEMUIOVector *qiov, int nb_sectors, BlockDriverCompletionFunc *cb, void *opaque) { - const uint8_t *first_buf; - int first_buf_index = 0, i; - - /* This is probably being paranoid, but handle cases of zero size - vectors. */ - for (i = 0; i < qiov->niov; i++) { - if (qiov->iov[i].iov_len) { - assert(qiov->iov[i].iov_len >= 512); - first_buf_index = i; - break; - } - } - - first_buf = qiov->iov[first_buf_index].iov_base; - - if (check_write_unsafe(bs, sector_num, first_buf, nb_sectors)) { - RawScrubberBounce *b; - int ret; - - /* write the first sector using sync I/O */ - ret = raw_write_scrubbed_bootsect(bs, first_buf); - if (ret < 0) { - return NULL; - } - - /* adjust request to be everything but first sector */ - - b = qemu_malloc(sizeof(*b)); - b->cb = cb; - b->opaque = opaque; - - qemu_iovec_init(&b->qiov, qiov->nalloc); - qemu_iovec_concat(&b->qiov, qiov, qiov->size); - - b->qiov.size -= 512; - b->qiov.iov[first_buf_index].iov_base += 512; - b->qiov.iov[first_buf_index].iov_len -= 512; - - return bdrv_aio_writev(bs->file, sector_num + 1, &b->qiov, - nb_sectors - 1, raw_aio_writev_scrubbed, b); - } - return bdrv_aio_writev(bs->file, sector_num, qiov, nb_sectors, cb, opaque); } diff --git a/block_int.h b/block_int.h index b863451774..e8e7156c92 100644 --- a/block_int.h +++ b/block_int.h @@ -148,7 +148,6 @@ struct BlockDriverState { int encrypted; /* if true, the media is encrypted */ int valid_key; /* if true, a valid encryption key has been set */ int sg; /* if true, the device is a /dev/sg* */ - int probed; /* if true, format was probed automatically */ /* event callback when inserting/removing */ void (*change_cb)(void *opaque); void *change_opaque;