From 3ac216270a62418519c08e88c17005a8f1539cf2 Mon Sep 17 00:00:00 2001 From: Peter Lieven Date: Fri, 28 Jun 2013 12:47:42 +0200 Subject: [PATCH] block: change default of .has_zero_init to 0 .has_zero_init defaults to 1 for all formats and protocols. this is a dangerous default since this means that all new added drivers need to manually overwrite it to 0 if they do not ensure that a device is zero initialized after bdrv_create(). if a driver needs to explicitly set this value to 1 its easier to verify the correctness in the review process. during review of the existing drivers it turned out that ssh and gluster had a wrong default of 1. both protocols support host_devices as backend which are not by default zero initialized. this wrong assumption will lead to possible corruption if qemu-img convert is used to write to such a backend. vpc and vmdk also defaulted to 1 altough they support fixed respectively flat extends. this has to be addresses in separate patches. both formats as well as the mentioned ssh and gluster are turned to the default of 0 with this patch for safety. a similar problem with the wrong default existed for iscsi most likely because the driver developer did oversee the default value of 1. Signed-off-by: Peter Lieven Signed-off-by: Kevin Wolf --- block.c | 8 +++++++- block/cow.c | 1 + block/qcow.c | 1 + block/qcow2.c | 1 + block/qed.c | 1 + block/raw-posix.c | 10 +--------- block/raw-win32.c | 7 +------ block/rbd.c | 1 + block/sheepdog.c | 1 + block/vdi.c | 1 + include/block/block.h | 1 + 11 files changed, 17 insertions(+), 16 deletions(-) diff --git a/block.c b/block.c index 0898f6b4b6..6c493ad457 100644 --- a/block.c +++ b/block.c @@ -2911,6 +2911,11 @@ void bdrv_flush_all(void) } } +int bdrv_has_zero_init_1(BlockDriverState *bs) +{ + return 1; +} + int bdrv_has_zero_init(BlockDriverState *bs) { assert(bs->drv); @@ -2919,7 +2924,8 @@ int bdrv_has_zero_init(BlockDriverState *bs) return bs->drv->bdrv_has_zero_init(bs); } - return 1; + /* safe default */ + return 0; } typedef struct BdrvCoIsAllocatedData { diff --git a/block/cow.c b/block/cow.c index 9f94599661..1cc2e89c7c 100644 --- a/block/cow.c +++ b/block/cow.c @@ -340,6 +340,7 @@ static BlockDriver bdrv_cow = { .bdrv_open = cow_open, .bdrv_close = cow_close, .bdrv_create = cow_create, + .bdrv_has_zero_init = bdrv_has_zero_init_1, .bdrv_read = cow_co_read, .bdrv_write = cow_co_write, diff --git a/block/qcow.c b/block/qcow.c index e2a64c79b1..5239bd68f1 100644 --- a/block/qcow.c +++ b/block/qcow.c @@ -892,6 +892,7 @@ static BlockDriver bdrv_qcow = { .bdrv_close = qcow_close, .bdrv_reopen_prepare = qcow_reopen_prepare, .bdrv_create = qcow_create, + .bdrv_has_zero_init = bdrv_has_zero_init_1, .bdrv_co_readv = qcow_co_readv, .bdrv_co_writev = qcow_co_writev, diff --git a/block/qcow2.c b/block/qcow2.c index 9383990193..0eceefe2cd 100644 --- a/block/qcow2.c +++ b/block/qcow2.c @@ -1785,6 +1785,7 @@ static BlockDriver bdrv_qcow2 = { .bdrv_close = qcow2_close, .bdrv_reopen_prepare = qcow2_reopen_prepare, .bdrv_create = qcow2_create, + .bdrv_has_zero_init = bdrv_has_zero_init_1, .bdrv_co_is_allocated = qcow2_co_is_allocated, .bdrv_set_key = qcow2_set_key, .bdrv_make_empty = qcow2_make_empty, diff --git a/block/qed.c b/block/qed.c index 4651403fef..f767b0528c 100644 --- a/block/qed.c +++ b/block/qed.c @@ -1574,6 +1574,7 @@ static BlockDriver bdrv_qed = { .bdrv_close = bdrv_qed_close, .bdrv_reopen_prepare = bdrv_qed_reopen_prepare, .bdrv_create = bdrv_qed_create, + .bdrv_has_zero_init = bdrv_has_zero_init_1, .bdrv_co_is_allocated = bdrv_qed_co_is_allocated, .bdrv_make_empty = bdrv_qed_make_empty, .bdrv_aio_readv = bdrv_qed_aio_readv, diff --git a/block/raw-posix.c b/block/raw-posix.c index 90ce9f86af..ba721d3f5b 100644 --- a/block/raw-posix.c +++ b/block/raw-posix.c @@ -1199,6 +1199,7 @@ static BlockDriver bdrv_file = { .bdrv_reopen_abort = raw_reopen_abort, .bdrv_close = raw_close, .bdrv_create = raw_create, + .bdrv_has_zero_init = bdrv_has_zero_init_1, .bdrv_co_is_allocated = raw_co_is_allocated, .bdrv_aio_readv = raw_aio_readv, @@ -1527,11 +1528,6 @@ static int hdev_create(const char *filename, QEMUOptionParameter *options) return ret; } -static int hdev_has_zero_init(BlockDriverState *bs) -{ - return 0; -} - static BlockDriver bdrv_host_device = { .format_name = "host_device", .protocol_name = "host_device", @@ -1544,7 +1540,6 @@ static BlockDriver bdrv_host_device = { .bdrv_reopen_abort = raw_reopen_abort, .bdrv_create = hdev_create, .create_options = raw_create_options, - .bdrv_has_zero_init = hdev_has_zero_init, .bdrv_aio_readv = raw_aio_readv, .bdrv_aio_writev = raw_aio_writev, @@ -1669,7 +1664,6 @@ static BlockDriver bdrv_host_floppy = { .bdrv_reopen_abort = raw_reopen_abort, .bdrv_create = hdev_create, .create_options = raw_create_options, - .bdrv_has_zero_init = hdev_has_zero_init, .bdrv_aio_readv = raw_aio_readv, .bdrv_aio_writev = raw_aio_writev, @@ -1771,7 +1765,6 @@ static BlockDriver bdrv_host_cdrom = { .bdrv_reopen_abort = raw_reopen_abort, .bdrv_create = hdev_create, .create_options = raw_create_options, - .bdrv_has_zero_init = hdev_has_zero_init, .bdrv_aio_readv = raw_aio_readv, .bdrv_aio_writev = raw_aio_writev, @@ -1893,7 +1886,6 @@ static BlockDriver bdrv_host_cdrom = { .bdrv_reopen_abort = raw_reopen_abort, .bdrv_create = hdev_create, .create_options = raw_create_options, - .bdrv_has_zero_init = hdev_has_zero_init, .bdrv_aio_readv = raw_aio_readv, .bdrv_aio_writev = raw_aio_writev, diff --git a/block/raw-win32.c b/block/raw-win32.c index 7c03b6df52..9b5b2af4e8 100644 --- a/block/raw-win32.c +++ b/block/raw-win32.c @@ -459,6 +459,7 @@ static BlockDriver bdrv_file = { .bdrv_file_open = raw_open, .bdrv_close = raw_close, .bdrv_create = raw_create, + .bdrv_has_zero_init = bdrv_has_zero_init_1, .bdrv_aio_readv = raw_aio_readv, .bdrv_aio_writev = raw_aio_writev, @@ -570,11 +571,6 @@ static int hdev_open(BlockDriverState *bs, QDict *options, int flags) return 0; } -static int hdev_has_zero_init(BlockDriverState *bs) -{ - return 0; -} - static BlockDriver bdrv_host_device = { .format_name = "host_device", .protocol_name = "host_device", @@ -582,7 +578,6 @@ static BlockDriver bdrv_host_device = { .bdrv_probe_device = hdev_probe_device, .bdrv_file_open = hdev_open, .bdrv_close = raw_close, - .bdrv_has_zero_init = hdev_has_zero_init, .bdrv_aio_readv = raw_aio_readv, .bdrv_aio_writev = raw_aio_writev, diff --git a/block/rbd.c b/block/rbd.c index 0f2608b287..cb71751218 100644 --- a/block/rbd.c +++ b/block/rbd.c @@ -996,6 +996,7 @@ static BlockDriver bdrv_rbd = { .bdrv_file_open = qemu_rbd_open, .bdrv_close = qemu_rbd_close, .bdrv_create = qemu_rbd_create, + .bdrv_has_zero_init = bdrv_has_zero_init_1, .bdrv_get_info = qemu_rbd_getinfo, .create_options = qemu_rbd_create_options, .bdrv_getlength = qemu_rbd_getlength, diff --git a/block/sheepdog.c b/block/sheepdog.c index 1b7c3f19b0..b397b5b4d3 100644 --- a/block/sheepdog.c +++ b/block/sheepdog.c @@ -2401,6 +2401,7 @@ static BlockDriver bdrv_sheepdog_unix = { .bdrv_file_open = sd_open, .bdrv_close = sd_close, .bdrv_create = sd_create, + .bdrv_has_zero_init = bdrv_has_zero_init_1, .bdrv_getlength = sd_getlength, .bdrv_truncate = sd_truncate, diff --git a/block/vdi.c b/block/vdi.c index 2662d89af6..8a915257e8 100644 --- a/block/vdi.c +++ b/block/vdi.c @@ -779,6 +779,7 @@ static BlockDriver bdrv_vdi = { .bdrv_close = vdi_close, .bdrv_reopen_prepare = vdi_reopen_prepare, .bdrv_create = vdi_create, + .bdrv_has_zero_init = bdrv_has_zero_init_1, .bdrv_co_is_allocated = vdi_co_is_allocated, .bdrv_make_empty = vdi_make_empty, diff --git a/include/block/block.h b/include/block/block.h index 2307f67b0e..dd8eca1be1 100644 --- a/include/block/block.h +++ b/include/block/block.h @@ -272,6 +272,7 @@ void bdrv_drain_all(void); int bdrv_discard(BlockDriverState *bs, int64_t sector_num, int nb_sectors); int bdrv_co_discard(BlockDriverState *bs, int64_t sector_num, int nb_sectors); +int bdrv_has_zero_init_1(BlockDriverState *bs); int bdrv_has_zero_init(BlockDriverState *bs); int bdrv_is_allocated(BlockDriverState *bs, int64_t sector_num, int nb_sectors, int *pnum);