Block layer patches

- Fix missing block_acct_setup() with -blockdev
 - Keep auto_backing_file post-migration
 - file-posix: Fixed O_DIRECT memory alignment
 - ide: Fix state after EXECUTE DEVICE DIAGNOSTIC and implement
   INITIALIZE DEVICE PARAMETERS
 - qemu-img: Wean documentation and help output off '?' for help
 - qcow2: fix memory leak and compiler warning
 - Code cleanups
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Merge tag 'for-upstream' of git://repo.or.cz/qemu/kevin into staging

Block layer patches

- Fix missing block_acct_setup() with -blockdev
- Keep auto_backing_file post-migration
- file-posix: Fixed O_DIRECT memory alignment
- ide: Fix state after EXECUTE DEVICE DIAGNOSTIC and implement
  INITIALIZE DEVICE PARAMETERS
- qemu-img: Wean documentation and help output off '?' for help
- qcow2: fix memory leak and compiler warning
- Code cleanups

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# gpg: Signature made Fri 30 Sep 2022 12:50:54 EDT
# gpg:                using RSA key DC3DEB159A9AF95D3D7456FE7F09B272C88F2FD6
# gpg:                issuer "kwolf@redhat.com"
# gpg: Good signature from "Kevin Wolf <kwolf@redhat.com>" [full]
# Primary key fingerprint: DC3D EB15 9A9A F95D 3D74  56FE 7F09 B272 C88F 2FD6

* tag 'for-upstream' of git://repo.or.cz/qemu/kevin:
  hw/ide/core.c: Implement ATA INITIALIZE_DEVICE_PARAMETERS command
  tests/qtest/ide-test: Verify that DIAGNOSTIC clears DEV to zero
  hw/ide/core: Clear LBA and drive bits for EXECUTE DEVICE DIAGNOSTIC
  tests/qtest/ide-test.c: Create disk image for use as a secondary
  piix_ide_reset: Use pci_set_* functions instead of direct access
  block: use the request length for iov alignment
  block: move bdrv_qiov_is_aligned to file-posix
  iotests/backing-file-invalidation: Add new test
  block/qed: Keep auto_backing_file if possible
  block/qcow2: Keep auto_backing_file if possible
  gluster: stop using .bdrv_needs_filename
  block: make serializing requests functions 'void'
  block: use bdrv_is_sg() helper instead of raw bs->sg reading
  block: add missed block_acct_setup with new block device init procedure
  block: pass OnOffAuto instead of bool to block_acct_setup()
  qemu-img: Wean documentation and help output off '?' for help
  block/qcow2-bitmap: Add missing cast to silent GCC error
  qcow2: fix memory leak in qcow2_read_extensions

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

block/accounting.c

@@ -38,13 +38,31 @@ void block_acct_init(BlockAcctStats *stats)
     if (qtest_enabled()) {
         clock_type = QEMU_CLOCK_VIRTUAL;
     }
+    stats->account_invalid = true;
+    stats->account_failed = true;
 }
 
-void block_acct_setup(BlockAcctStats *stats, bool account_invalid,
+static bool bool_from_onoffauto(OnOffAuto val, bool def)
-                      bool account_failed)
 {
-    stats->account_invalid = account_invalid;
+    switch (val) {
-    stats->account_failed = account_failed;
+    case ON_OFF_AUTO_AUTO:
+        return def;
+    case ON_OFF_AUTO_ON:
+        return true;
+    case ON_OFF_AUTO_OFF:
+        return false;
+    default:
+        abort();
+    }
+}
+
+void block_acct_setup(BlockAcctStats *stats, enum OnOffAuto account_invalid,
+                      enum OnOffAuto account_failed)
+{
+    stats->account_invalid = bool_from_onoffauto(account_invalid,
+                                                 stats->account_invalid);
+    stats->account_failed = bool_from_onoffauto(account_failed,
+                                                stats->account_failed);
 }
 
 void block_acct_cleanup(BlockAcctStats *stats)

block/file-posix.c

@@ -1295,7 +1295,7 @@ static void raw_refresh_limits(BlockDriverState *bs, Error **errp)
     }
 #endif
 
-    if (bs->sg || S_ISBLK(st.st_mode)) {
+    if (bdrv_is_sg(bs) || S_ISBLK(st.st_mode)) {
         int ret = hdev_get_max_hw_transfer(s->fd, &st);
 
         if (ret > 0 && ret <= BDRV_REQUEST_MAX_BYTES) {
@@ -2061,6 +2061,28 @@ static int coroutine_fn raw_thread_pool_submit(BlockDriverState *bs,
     return thread_pool_submit_co(pool, func, arg);
 }
 
+/*
+ * Check if all memory in this vector is sector aligned.
+ */
+static bool bdrv_qiov_is_aligned(BlockDriverState *bs, QEMUIOVector *qiov)
+{
+    int i;
+    size_t alignment = bdrv_min_mem_align(bs);
+    size_t len = bs->bl.request_alignment;
+    IO_CODE();
+
+    for (i = 0; i < qiov->niov; i++) {
+        if ((uintptr_t) qiov->iov[i].iov_base % alignment) {
+            return false;
+        }
+        if (qiov->iov[i].iov_len % len) {
+            return false;
+        }
+    }
+
+    return true;
+}
+
 static int coroutine_fn raw_co_prw(BlockDriverState *bs, uint64_t offset,
                                    uint64_t bytes, QEMUIOVector *qiov, int type)
 {

block/gluster.c

@@ -1555,7 +1555,6 @@ static BlockDriver bdrv_gluster = {
     .format_name                  = "gluster",
     .protocol_name                = "gluster",
     .instance_size                = sizeof(BDRVGlusterState),
-    .bdrv_needs_filename          = false,
     .bdrv_file_open               = qemu_gluster_open,
     .bdrv_reopen_prepare          = qemu_gluster_reopen_prepare,
     .bdrv_reopen_commit           = qemu_gluster_reopen_commit,
@@ -1585,7 +1584,6 @@ static BlockDriver bdrv_gluster_tcp = {
     .format_name                  = "gluster",
     .protocol_name                = "gluster+tcp",
     .instance_size                = sizeof(BDRVGlusterState),
-    .bdrv_needs_filename          = false,
     .bdrv_file_open               = qemu_gluster_open,
     .bdrv_reopen_prepare          = qemu_gluster_reopen_prepare,
     .bdrv_reopen_commit           = qemu_gluster_reopen_commit,
@@ -1615,7 +1613,6 @@ static BlockDriver bdrv_gluster_unix = {
     .format_name                  = "gluster",
     .protocol_name                = "gluster+unix",
     .instance_size                = sizeof(BDRVGlusterState),
-    .bdrv_needs_filename          = true,
     .bdrv_file_open               = qemu_gluster_open,
     .bdrv_reopen_prepare          = qemu_gluster_reopen_prepare,
     .bdrv_reopen_commit           = qemu_gluster_reopen_commit,
@@ -1651,7 +1648,6 @@ static BlockDriver bdrv_gluster_rdma = {
     .format_name                  = "gluster",
     .protocol_name                = "gluster+rdma",
     .instance_size                = sizeof(BDRVGlusterState),
-    .bdrv_needs_filename          = true,
     .bdrv_file_open               = qemu_gluster_open,
     .bdrv_reopen_prepare          = qemu_gluster_reopen_prepare,
     .bdrv_reopen_commit           = qemu_gluster_reopen_commit,

block/io.c

@@ -828,20 +828,16 @@ bdrv_find_conflicting_request(BdrvTrackedRequest *self)
 }
 
 /* Called with self->bs->reqs_lock held */
-static bool coroutine_fn
+static void coroutine_fn
 bdrv_wait_serialising_requests_locked(BdrvTrackedRequest *self)
 {
     BdrvTrackedRequest *req;
-    bool waited = false;
 
     while ((req = bdrv_find_conflicting_request(self))) {
         self->waiting_for = req;
         qemu_co_queue_wait(&req->wait_queue, &self->bs->reqs_lock);
         self->waiting_for = NULL;
-        waited = true;
     }
-
-    return waited;
 }
 
 /* Called with req->bs->reqs_lock held */
@@ -934,36 +930,31 @@ void bdrv_dec_in_flight(BlockDriverState *bs)
     bdrv_wakeup(bs);
 }
 
-static bool coroutine_fn bdrv_wait_serialising_requests(BdrvTrackedRequest *self)
+static void coroutine_fn
+bdrv_wait_serialising_requests(BdrvTrackedRequest *self)
 {
     BlockDriverState *bs = self->bs;
-    bool waited = false;
 
     if (!qatomic_read(&bs->serialising_in_flight)) {
-        return false;
+        return;
     }
 
     qemu_co_mutex_lock(&bs->reqs_lock);
-    waited = bdrv_wait_serialising_requests_locked(self);
+    bdrv_wait_serialising_requests_locked(self);
     qemu_co_mutex_unlock(&bs->reqs_lock);
-
-    return waited;
 }
 
-bool coroutine_fn bdrv_make_request_serialising(BdrvTrackedRequest *req,
+void coroutine_fn bdrv_make_request_serialising(BdrvTrackedRequest *req,
                                                 uint64_t align)
 {
-    bool waited;
     IO_CODE();
 
     qemu_co_mutex_lock(&req->bs->reqs_lock);
 
     tracked_request_set_serialising(req, align);
-    waited = bdrv_wait_serialising_requests_locked(req);
+    bdrv_wait_serialising_requests_locked(req);
 
     qemu_co_mutex_unlock(&req->bs->reqs_lock);
-
-    return waited;
 }
 
 int bdrv_check_qiov_request(int64_t offset, int64_t bytes,
@@ -3236,27 +3227,6 @@ void *qemu_try_blockalign0(BlockDriverState *bs, size_t size)
     return mem;
 }
 
-/*
- * Check if all memory in this vector is sector aligned.
- */
-bool bdrv_qiov_is_aligned(BlockDriverState *bs, QEMUIOVector *qiov)
-{
-    int i;
-    size_t alignment = bdrv_min_mem_align(bs);
-    IO_CODE();
-
-    for (i = 0; i < qiov->niov; i++) {
-        if ((uintptr_t) qiov->iov[i].iov_base % alignment) {
-            return false;
-        }
-        if (qiov->iov[i].iov_len % alignment) {
-            return false;
-        }
-    }
-
-    return true;
-}
-
 void bdrv_io_plug(BlockDriverState *bs)
 {
     BdrvChild *child;

block/iscsi.c

@@ -2065,7 +2065,7 @@ static void iscsi_refresh_limits(BlockDriverState *bs, Error **errp)
     uint64_t max_xfer_len = iscsilun->use_16_for_rw ? 0xffffffff : 0xffff;
     unsigned int block_size = MAX(BDRV_SECTOR_SIZE, iscsilun->block_size);
 
-    assert(iscsilun->block_size >= BDRV_SECTOR_SIZE || bs->sg);
+    assert(iscsilun->block_size >= BDRV_SECTOR_SIZE || bdrv_is_sg(bs));
 
     bs->bl.request_alignment = block_size;
 

block/qcow2-bitmap.c

@@ -1208,7 +1208,7 @@ int qcow2_reopen_bitmaps_rw(BlockDriverState *bs, Error **errp)
         }
     }
 
-    g_slist_foreach(ro_dirty_bitmaps, set_readonly_helper, false);
+    g_slist_foreach(ro_dirty_bitmaps, set_readonly_helper, (gpointer)false);
     ret = 0;
 
 out:

block/qcow2.c

@@ -275,6 +275,7 @@ static int qcow2_read_extensions(BlockDriverState *bs, uint64_t start_offset,
                 if (ret < 0) {
                     error_setg_errno(errp, -ret, "ERROR: ext_feature_table: "
                                      "Could not read table");
+                    g_free(feature_table);
                     return ret;
                 }
 
@@ -1696,16 +1697,27 @@ static int coroutine_fn qcow2_do_open(BlockDriverState *bs, QDict *options,
             ret = -EINVAL;
             goto fail;
         }
+
+        s->image_backing_file = g_malloc(len + 1);
         ret = bdrv_pread(bs->file, header.backing_file_offset, len,
-                         bs->auto_backing_file, 0);
+                         s->image_backing_file, 0);
         if (ret < 0) {
             error_setg_errno(errp, -ret, "Could not read backing file name");
             goto fail;
         }
-        bs->auto_backing_file[len] = '\0';
+        s->image_backing_file[len] = '\0';
-        pstrcpy(bs->backing_file, sizeof(bs->backing_file),
+
-                bs->auto_backing_file);
+        /*
-        s->image_backing_file = g_strdup(bs->auto_backing_file);
+         * Update only when something has changed.  This function is called by
+         * qcow2_co_invalidate_cache(), and we do not want to reset
+         * auto_backing_file unless necessary.
+         */
+        if (!g_str_equal(s->image_backing_file, bs->backing_file)) {
+            pstrcpy(bs->backing_file, sizeof(bs->backing_file),
+                    s->image_backing_file);
+            pstrcpy(bs->auto_backing_file, sizeof(bs->auto_backing_file),
+                    s->image_backing_file);
+        }
     }
 
     /*

block/qed.c

@@ -445,6 +445,8 @@ static int coroutine_fn bdrv_qed_do_open(BlockDriverState *bs, QDict *options,
     }
 
     if ((s->header.features & QED_F_BACKING_FILE)) {
+        g_autofree char *backing_file_str = NULL;
+
         if ((uint64_t)s->header.backing_filename_offset +
             s->header.backing_filename_size >
             s->header.cluster_size * s->header.header_size) {
@@ -452,16 +454,21 @@ static int coroutine_fn bdrv_qed_do_open(BlockDriverState *bs, QDict *options,
             return -EINVAL;
         }
 
+        backing_file_str = g_malloc(sizeof(bs->backing_file));
         ret = qed_read_string(bs->file, s->header.backing_filename_offset,
                               s->header.backing_filename_size,
-                              bs->auto_backing_file,
+                              backing_file_str, sizeof(bs->backing_file));
-                              sizeof(bs->auto_backing_file));
         if (ret < 0) {
             error_setg(errp, "Failed to read backing filename");
             return ret;
         }
-        pstrcpy(bs->backing_file, sizeof(bs->backing_file),
+
-                bs->auto_backing_file);
+        if (!g_str_equal(backing_file_str, bs->backing_file)) {
+            pstrcpy(bs->backing_file, sizeof(bs->backing_file),
+                    backing_file_str);
+            pstrcpy(bs->auto_backing_file, sizeof(bs->auto_backing_file),
+                    backing_file_str);
+        }
 
         if (s->header.features & QED_F_BACKING_FORMAT_NO_PROBE) {
             pstrcpy(bs->backing_format, sizeof(bs->backing_format), "raw");

block/raw-format.c

@@ -463,7 +463,7 @@ static int raw_open(BlockDriverState *bs, QDict *options, int flags,
         return -EINVAL;
     }
 
-    bs->sg = bs->file->bs->sg;
+    bs->sg = bdrv_is_sg(bs->file->bs);
     bs->supported_write_flags = BDRV_REQ_WRITE_UNCHANGED |
         (BDRV_REQ_FUA & bs->file->bs->supported_write_flags);
     bs->supported_zero_flags = BDRV_REQ_WRITE_UNCHANGED |
@@ -489,7 +489,7 @@ static int raw_open(BlockDriverState *bs, QDict *options, int flags,
         return ret;
     }
 
-    if (bs->sg && (s->offset || s->has_size)) {
+    if (bdrv_is_sg(bs) && (s->offset || s->has_size)) {
         error_setg(errp, "Cannot use offset/size with SCSI generic devices");
         return -EINVAL;
     }

blockdev.c

@@ -455,6 +455,17 @@ static void extract_common_blockdev_options(QemuOpts *opts, int *bdrv_flags,
     }
 }
 
+static OnOffAuto account_get_opt(QemuOpts *opts, const char *name)
+{
+    if (!qemu_opt_find(opts, name)) {
+        return ON_OFF_AUTO_AUTO;
+    }
+    if (qemu_opt_get_bool(opts, name, true)) {
+        return ON_OFF_AUTO_ON;
+    }
+    return ON_OFF_AUTO_OFF;
+}
+
 /* Takes the ownership of bs_opts */
 static BlockBackend *blockdev_init(const char *file, QDict *bs_opts,
                                    Error **errp)
@@ -462,7 +473,7 @@ static BlockBackend *blockdev_init(const char *file, QDict *bs_opts,
     const char *buf;
     int bdrv_flags = 0;
     int on_read_error, on_write_error;
-    bool account_invalid, account_failed;
+    OnOffAuto account_invalid, account_failed;
     bool writethrough, read_only;
     BlockBackend *blk;
     BlockDriverState *bs;
@@ -496,8 +507,8 @@ static BlockBackend *blockdev_init(const char *file, QDict *bs_opts,
     /* extract parameters */
     snapshot = qemu_opt_get_bool(opts, "snapshot", 0);
 
-    account_invalid = qemu_opt_get_bool(opts, "stats-account-invalid", true);
+    account_invalid = account_get_opt(opts, "stats-account-invalid");
-    account_failed = qemu_opt_get_bool(opts, "stats-account-failed", true);
+    account_failed = account_get_opt(opts, "stats-account-failed");
 
     writethrough = !qemu_opt_get_bool(opts, BDRV_OPT_CACHE_WB, true);
 

docs/tools/qemu-img.rst

@@ -57,7 +57,7 @@ cases. See below for a description of the supported disk formats.
 *OUTPUT_FMT* is the destination format.
 
 *OPTIONS* is a comma separated list of format specific options in a
-name=value format. Use ``-o ?`` for an overview of the options supported
+name=value format. Use ``-o help`` for an overview of the options supported
 by the used format or see the format descriptions below for details.
 
 *SNAPSHOT_PARAM* is param used for internal snapshot, format is

hw/block/block.c

@@ -205,6 +205,8 @@ bool blkconf_apply_backend_options(BlockConf *conf, bool readonly,
     blk_set_enable_write_cache(blk, wce);
     blk_set_on_error(blk, rerror, werror);
 
+    block_acct_setup(blk_get_stats(blk), conf->account_invalid,
+                     conf->account_failed);
     return true;
 }
 

hw/ide/core.c

@@ -1340,6 +1340,11 @@ static void ide_reset(IDEState *s)
         s->pio_aiocb = NULL;
     }
 
+    if (s->reset_reverts) {
+        s->reset_reverts = false;
+        s->heads         = s->drive_heads;
+        s->sectors       = s->drive_sectors;
+    }
     if (s->drive_kind == IDE_CFATA)
         s->mult_sectors = 0;
     else
@@ -1618,6 +1623,20 @@ static bool cmd_check_power_mode(IDEState *s, uint8_t cmd)
     return true;
 }
 
+/* INITIALIZE DEVICE PARAMETERS */
+static bool cmd_specify(IDEState *s, uint8_t cmd)
+{
+    if (s->blk && s->drive_kind != IDE_CD) {
+        s->heads = (s->select & (ATA_DEV_HS)) + 1;
+        s->sectors = s->nsector;
+        ide_set_irq(s->bus);
+    } else {
+        ide_abort_command(s);
+    }
+
+    return true;
+}
+
 static bool cmd_set_features(IDEState *s, uint8_t cmd)
 {
     uint16_t *identify_data;
@@ -1641,7 +1660,11 @@ static bool cmd_set_features(IDEState *s, uint8_t cmd)
         ide_flush_cache(s);
         return false;
     case 0xcc: /* reverting to power-on defaults enable */
+        s->reset_reverts = true;
+        return true;
     case 0x66: /* reverting to power-on defaults disable */
+        s->reset_reverts = false;
+        return true;
     case 0xaa: /* read look-ahead enable */
     case 0x55: /* read look-ahead disable */
     case 0x05: /* set advanced power management mode */
@@ -1704,8 +1727,14 @@ static bool cmd_identify_packet(IDEState *s, uint8_t cmd)
     return false;
 }
 
+/* EXECUTE DEVICE DIAGNOSTIC */
 static bool cmd_exec_dev_diagnostic(IDEState *s, uint8_t cmd)
 {
+    /*
+     * Clear the device register per the ATA (v6) specification,
+     * because ide_set_signature does not clear LBA or drive bits.
+     */
+    s->select = (ATA_DEV_ALWAYS_ON);
     ide_set_signature(s);
 
     if (s->drive_kind == IDE_CD) {
@@ -2045,7 +2074,7 @@ static const struct {
     [WIN_SEEK]                    = { cmd_seek, HD_CFA_OK | SET_DSC },
     [CFA_TRANSLATE_SECTOR]        = { cmd_cfa_translate_sector, CFA_OK },
     [WIN_DIAGNOSE]                = { cmd_exec_dev_diagnostic, ALL_OK },
-    [WIN_SPECIFY]                 = { cmd_nop, HD_CFA_OK | SET_DSC },
+    [WIN_SPECIFY]                 = { cmd_specify, HD_CFA_OK | SET_DSC },
     [WIN_STANDBYNOW2]             = { cmd_nop, HD_CFA_OK },
     [WIN_IDLEIMMEDIATE2]          = { cmd_nop, HD_CFA_OK },
     [WIN_STANDBY2]                = { cmd_nop, HD_CFA_OK },
@@ -2535,8 +2564,8 @@ int ide_init_drive(IDEState *s, BlockBackend *blk, IDEDriveKind kind,
 
     blk_get_geometry(blk, &nb_sectors);
     s->cylinders = cylinders;
-    s->heads = heads;
+    s->heads = s->drive_heads = heads;
-    s->sectors = secs;
+    s->sectors = s->drive_sectors = secs;
     s->chs_trans = chs_trans;
     s->nb_sectors = nb_sectors;
     s->wwn = wwn;

hw/ide/piix.c

@@ -21,6 +21,10 @@
  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  * THE SOFTWARE.
+ *
+ * References:
+ *  [1] 82371FB (PIIX) AND 82371SB (PIIX3) PCI ISA IDE XCELERATOR,
+ *      290550-002, Intel Corporation, April 1997.
  */
 
 #include "qemu/osdep.h"
@@ -114,14 +118,11 @@ static void piix_ide_reset(DeviceState *dev)
         ide_bus_reset(&d->bus[i]);
     }
 
-    /* TODO: this is the default. do not override. */
+    /* PCI command register default value (0000h) per [1, p.48].  */
-    pci_conf[PCI_COMMAND] = 0x00;
+    pci_set_word(pci_conf + PCI_COMMAND, 0x0000);
-    /* TODO: this is the default. do not override. */
+    pci_set_word(pci_conf + PCI_STATUS,
-    pci_conf[PCI_COMMAND + 1] = 0x00;
+                 PCI_STATUS_DEVSEL_MEDIUM | PCI_STATUS_FAST_BACK);
-    /* TODO: use pci_set_word */
+    pci_set_byte(pci_conf + 0x20, 0x01);  /* BMIBA: 20-23h */
-    pci_conf[PCI_STATUS] = PCI_STATUS_FAST_BACK;
-    pci_conf[PCI_STATUS + 1] = PCI_STATUS_DEVSEL_MEDIUM >> 8;
-    pci_conf[0x20] = 0x01; /* BMIBA: 20-23h */
 }
 
 static int pci_piix_init_ports(PCIIDEState *d)

include/block/accounting.h

@@ -27,7 +27,7 @@
 
 #include "qemu/timed-average.h"
 #include "qemu/thread.h"
-#include "qapi/qapi-builtin-types.h"
+#include "qapi/qapi-types-common.h"
 
 typedef struct BlockAcctTimedStats BlockAcctTimedStats;
 typedef struct BlockAcctStats BlockAcctStats;
@@ -100,8 +100,8 @@ typedef struct BlockAcctCookie {
 } BlockAcctCookie;
 
 void block_acct_init(BlockAcctStats *stats);
-void block_acct_setup(BlockAcctStats *stats, bool account_invalid,
+void block_acct_setup(BlockAcctStats *stats, enum OnOffAuto account_invalid,
-                     bool account_failed);
+                      enum OnOffAuto account_failed);
 void block_acct_cleanup(BlockAcctStats *stats);
 void block_acct_add_interval(BlockAcctStats *stats, unsigned interval_length);
 BlockAcctTimedStats *block_acct_interval_next(BlockAcctStats *stats,

include/block/block-io.h

@@ -150,7 +150,6 @@ void *qemu_blockalign(BlockDriverState *bs, size_t size);
 void *qemu_blockalign0(BlockDriverState *bs, size_t size);
 void *qemu_try_blockalign(BlockDriverState *bs, size_t size);
 void *qemu_try_blockalign0(BlockDriverState *bs, size_t size);
-bool bdrv_qiov_is_aligned(BlockDriverState *bs, QEMUIOVector *qiov);
 
 void bdrv_enable_copy_on_read(BlockDriverState *bs);
 void bdrv_disable_copy_on_read(BlockDriverState *bs);

include/block/block_int-io.h

@@ -73,7 +73,7 @@ static inline int coroutine_fn bdrv_co_pwrite(BdrvChild *child,
     return bdrv_co_pwritev(child, offset, bytes, &qiov, flags);
 }
 
-bool coroutine_fn bdrv_make_request_serialising(BdrvTrackedRequest *req,
+void coroutine_fn bdrv_make_request_serialising(BdrvTrackedRequest *req,
                                                 uint64_t align);
 BdrvTrackedRequest *coroutine_fn bdrv_co_get_self_request(BlockDriverState *bs);
 

include/hw/block/block.h

@@ -31,6 +31,7 @@ typedef struct BlockConf {
     uint32_t lcyls, lheads, lsecs;
     OnOffAuto wce;
     bool share_rw;
+    OnOffAuto account_invalid, account_failed;
     BlockdevOnError rerror;
     BlockdevOnError werror;
 } BlockConf;
@@ -61,7 +62,11 @@ static inline unsigned int get_physical_block_exp(BlockConf *conf)
                        _conf.discard_granularity, -1),                  \
     DEFINE_PROP_ON_OFF_AUTO("write-cache", _state, _conf.wce,           \
                             ON_OFF_AUTO_AUTO),                          \
-    DEFINE_PROP_BOOL("share-rw", _state, _conf.share_rw, false)
+    DEFINE_PROP_BOOL("share-rw", _state, _conf.share_rw, false),        \
+    DEFINE_PROP_ON_OFF_AUTO("account-invalid", _state,                  \
+                            _conf.account_invalid, ON_OFF_AUTO_AUTO),   \
+    DEFINE_PROP_ON_OFF_AUTO("account-failed", _state,                   \
+                            _conf.account_failed, ON_OFF_AUTO_AUTO)
 
 #define DEFINE_BLOCK_PROPERTIES(_state, _conf)                          \
     DEFINE_PROP_DRIVE("drive", _state, _conf.blk),                      \

include/hw/ide/internal.h

@@ -375,6 +375,7 @@ struct IDEState {
     uint8_t unit;
     /* ide config */
     IDEDriveKind drive_kind;
+    int drive_heads, drive_sectors;
     int cylinders, heads, sectors, chs_trans;
     int64_t nb_sectors;
     int mult_sectors;
@@ -401,6 +402,8 @@ struct IDEState {
     uint8_t select;
     uint8_t status;
 
+    bool reset_reverts;
+
     /* set for lba48 access */
     uint8_t lba48;
     BlockBackend *blk;

qemu-img.c

@@ -164,8 +164,8 @@ void help(void)
            "  'output_filename' is the destination disk image filename\n"
            "  'output_fmt' is the destination format\n"
            "  'options' is a comma separated list of format specific options in a\n"
-           "    name=value format. Use -o ? for an overview of the options supported by the\n"
+           "    name=value format. Use -o help for an overview of the options supported by\n"
-           "    used format\n"
+           "    the used format\n"
            "  'snapshot_param' is param used for internal snapshot, format\n"
            "    is 'snapshot.id=[ID],snapshot.name=[NAME]', or\n"
            "    '[ID_OR_NAME]'\n"

tests/qemu-iotests/172.out

@@ -28,6 +28,8 @@ Testing:
                 discard_granularity = 4294967295 (4 GiB)
                 write-cache = "auto"
                 share-rw = false
+                account-invalid = "auto"
+                account-failed = "auto"
                 drive-type = "288"
 
 
@@ -55,6 +57,8 @@ Testing: -fda TEST_DIR/t.qcow2
                 discard_granularity = 4294967295 (4 GiB)
                 write-cache = "auto"
                 share-rw = false
+                account-invalid = "auto"
+                account-failed = "auto"
                 drive-type = "144"
 floppy0 (NODE_NAME): TEST_DIR/t.qcow2 (qcow2)
     Attached to:      /machine/unattached/device[N]
@@ -92,6 +96,8 @@ Testing: -fdb TEST_DIR/t.qcow2
                 discard_granularity = 4294967295 (4 GiB)
                 write-cache = "auto"
                 share-rw = false
+                account-invalid = "auto"
+                account-failed = "auto"
                 drive-type = "144"
               dev: floppy, id ""
                 unit = 0 (0x0)
@@ -104,6 +110,8 @@ Testing: -fdb TEST_DIR/t.qcow2
                 discard_granularity = 4294967295 (4 GiB)
                 write-cache = "auto"
                 share-rw = false
+                account-invalid = "auto"
+                account-failed = "auto"
                 drive-type = "288"
 floppy1 (NODE_NAME): TEST_DIR/t.qcow2 (qcow2)
     Attached to:      /machine/unattached/device[N]
@@ -145,6 +153,8 @@ Testing: -fda TEST_DIR/t.qcow2 -fdb TEST_DIR/t.qcow2.2
                 discard_granularity = 4294967295 (4 GiB)
                 write-cache = "auto"
                 share-rw = false
+                account-invalid = "auto"
+                account-failed = "auto"
                 drive-type = "144"
               dev: floppy, id ""
                 unit = 0 (0x0)
@@ -157,6 +167,8 @@ Testing: -fda TEST_DIR/t.qcow2 -fdb TEST_DIR/t.qcow2.2
                 discard_granularity = 4294967295 (4 GiB)
                 write-cache = "auto"
                 share-rw = false
+                account-invalid = "auto"
+                account-failed = "auto"
                 drive-type = "144"
 floppy0 (NODE_NAME): TEST_DIR/t.qcow2 (qcow2)
     Attached to:      /machine/unattached/device[N]
@@ -199,6 +211,8 @@ Testing: -fdb
                 discard_granularity = 4294967295 (4 GiB)
                 write-cache = "auto"
                 share-rw = false
+                account-invalid = "auto"
+                account-failed = "auto"
                 drive-type = "288"
               dev: floppy, id ""
                 unit = 0 (0x0)
@@ -211,6 +225,8 @@ Testing: -fdb
                 discard_granularity = 4294967295 (4 GiB)
                 write-cache = "auto"
                 share-rw = false
+                account-invalid = "auto"
+                account-failed = "auto"
                 drive-type = "288"
 
 
@@ -238,6 +254,8 @@ Testing: -drive if=floppy,file=TEST_DIR/t.qcow2
                 discard_granularity = 4294967295 (4 GiB)
                 write-cache = "auto"
                 share-rw = false
+                account-invalid = "auto"
+                account-failed = "auto"
                 drive-type = "144"
 floppy0 (NODE_NAME): TEST_DIR/t.qcow2 (qcow2)
     Attached to:      /machine/unattached/device[N]
@@ -275,6 +293,8 @@ Testing: -drive if=floppy,file=TEST_DIR/t.qcow2,index=1
                 discard_granularity = 4294967295 (4 GiB)
                 write-cache = "auto"
                 share-rw = false
+                account-invalid = "auto"
+                account-failed = "auto"
                 drive-type = "144"
               dev: floppy, id ""
                 unit = 0 (0x0)
@@ -287,6 +307,8 @@ Testing: -drive if=floppy,file=TEST_DIR/t.qcow2,index=1
                 discard_granularity = 4294967295 (4 GiB)
                 write-cache = "auto"
                 share-rw = false
+                account-invalid = "auto"
+                account-failed = "auto"
                 drive-type = "288"
 floppy1 (NODE_NAME): TEST_DIR/t.qcow2 (qcow2)
     Attached to:      /machine/unattached/device[N]
@@ -328,6 +350,8 @@ Testing: -drive if=floppy,file=TEST_DIR/t.qcow2 -drive if=floppy,file=TEST_DIR/t
                 discard_granularity = 4294967295 (4 GiB)
                 write-cache = "auto"
                 share-rw = false
+                account-invalid = "auto"
+                account-failed = "auto"
                 drive-type = "144"
               dev: floppy, id ""
                 unit = 0 (0x0)
@@ -340,6 +364,8 @@ Testing: -drive if=floppy,file=TEST_DIR/t.qcow2 -drive if=floppy,file=TEST_DIR/t
                 discard_granularity = 4294967295 (4 GiB)
                 write-cache = "auto"
                 share-rw = false
+                account-invalid = "auto"
+                account-failed = "auto"
                 drive-type = "144"
 floppy0 (NODE_NAME): TEST_DIR/t.qcow2 (qcow2)
     Attached to:      /machine/unattached/device[N]
@@ -385,6 +411,8 @@ Testing: -drive if=none,file=TEST_DIR/t.qcow2 -device floppy,drive=none0
                 discard_granularity = 4294967295 (4 GiB)
                 write-cache = "auto"
                 share-rw = false
+                account-invalid = "auto"
+                account-failed = "auto"
                 drive-type = "144"
 none0 (NODE_NAME): TEST_DIR/t.qcow2 (qcow2)
     Attached to:      /machine/peripheral-anon/device[N]
@@ -422,6 +450,8 @@ Testing: -drive if=none,file=TEST_DIR/t.qcow2 -device floppy,drive=none0,unit=1
                 discard_granularity = 4294967295 (4 GiB)
                 write-cache = "auto"
                 share-rw = false
+                account-invalid = "auto"
+                account-failed = "auto"
                 drive-type = "144"
 none0 (NODE_NAME): TEST_DIR/t.qcow2 (qcow2)
     Attached to:      /machine/peripheral-anon/device[N]
@@ -459,6 +489,8 @@ Testing: -drive if=none,file=TEST_DIR/t.qcow2 -drive if=none,file=TEST_DIR/t.qco
                 discard_granularity = 4294967295 (4 GiB)
                 write-cache = "auto"
                 share-rw = false
+                account-invalid = "auto"
+                account-failed = "auto"
                 drive-type = "144"
               dev: floppy, id ""
                 unit = 0 (0x0)
@@ -471,6 +503,8 @@ Testing: -drive if=none,file=TEST_DIR/t.qcow2 -drive if=none,file=TEST_DIR/t.qco
                 discard_granularity = 4294967295 (4 GiB)
                 write-cache = "auto"
                 share-rw = false
+                account-invalid = "auto"
+                account-failed = "auto"
                 drive-type = "144"
 none0 (NODE_NAME): TEST_DIR/t.qcow2 (qcow2)
     Attached to:      /machine/peripheral-anon/device[N]
@@ -522,6 +556,8 @@ Testing: -fda TEST_DIR/t.qcow2 -drive if=none,file=TEST_DIR/t.qcow2.2 -device fl
                 discard_granularity = 4294967295 (4 GiB)
                 write-cache = "auto"
                 share-rw = false
+                account-invalid = "auto"
+                account-failed = "auto"
                 drive-type = "144"
               dev: floppy, id ""
                 unit = 0 (0x0)
@@ -534,6 +570,8 @@ Testing: -fda TEST_DIR/t.qcow2 -drive if=none,file=TEST_DIR/t.qcow2.2 -device fl
                 discard_granularity = 4294967295 (4 GiB)
                 write-cache = "auto"
                 share-rw = false
+                account-invalid = "auto"
+                account-failed = "auto"
                 drive-type = "144"
 floppy0 (NODE_NAME): TEST_DIR/t.qcow2 (qcow2)
     Attached to:      /machine/unattached/device[N]
@@ -576,6 +614,8 @@ Testing: -fda TEST_DIR/t.qcow2 -drive if=none,file=TEST_DIR/t.qcow2.2 -device fl
                 discard_granularity = 4294967295 (4 GiB)
                 write-cache = "auto"
                 share-rw = false
+                account-invalid = "auto"
+                account-failed = "auto"
                 drive-type = "144"
               dev: floppy, id ""
                 unit = 0 (0x0)
@@ -588,6 +628,8 @@ Testing: -fda TEST_DIR/t.qcow2 -drive if=none,file=TEST_DIR/t.qcow2.2 -device fl
                 discard_granularity = 4294967295 (4 GiB)
                 write-cache = "auto"
                 share-rw = false
+                account-invalid = "auto"
+                account-failed = "auto"
                 drive-type = "144"
 floppy0 (NODE_NAME): TEST_DIR/t.qcow2 (qcow2)
     Attached to:      /machine/unattached/device[N]
@@ -630,6 +672,8 @@ Testing: -fdb TEST_DIR/t.qcow2 -drive if=none,file=TEST_DIR/t.qcow2.2 -device fl
                 discard_granularity = 4294967295 (4 GiB)
                 write-cache = "auto"
                 share-rw = false
+                account-invalid = "auto"
+                account-failed = "auto"
                 drive-type = "144"
               dev: floppy, id ""
                 unit = 1 (0x1)
@@ -642,6 +686,8 @@ Testing: -fdb TEST_DIR/t.qcow2 -drive if=none,file=TEST_DIR/t.qcow2.2 -device fl
                 discard_granularity = 4294967295 (4 GiB)
                 write-cache = "auto"
                 share-rw = false
+                account-invalid = "auto"
+                account-failed = "auto"
                 drive-type = "144"
 floppy1 (NODE_NAME): TEST_DIR/t.qcow2 (qcow2)
     Attached to:      /machine/unattached/device[N]
@@ -684,6 +730,8 @@ Testing: -fdb TEST_DIR/t.qcow2 -drive if=none,file=TEST_DIR/t.qcow2.2 -device fl
                 discard_granularity = 4294967295 (4 GiB)
                 write-cache = "auto"
                 share-rw = false
+                account-invalid = "auto"
+                account-failed = "auto"
                 drive-type = "144"
               dev: floppy, id ""
                 unit = 1 (0x1)
@@ -696,6 +744,8 @@ Testing: -fdb TEST_DIR/t.qcow2 -drive if=none,file=TEST_DIR/t.qcow2.2 -device fl
                 discard_granularity = 4294967295 (4 GiB)
                 write-cache = "auto"
                 share-rw = false
+                account-invalid = "auto"
+                account-failed = "auto"
                 drive-type = "144"
 floppy1 (NODE_NAME): TEST_DIR/t.qcow2 (qcow2)
     Attached to:      /machine/unattached/device[N]
@@ -747,6 +797,8 @@ Testing: -drive if=floppy,file=TEST_DIR/t.qcow2 -drive if=none,file=TEST_DIR/t.q
                 discard_granularity = 4294967295 (4 GiB)
                 write-cache = "auto"
                 share-rw = false
+                account-invalid = "auto"
+                account-failed = "auto"
                 drive-type = "144"
               dev: floppy, id ""
                 unit = 0 (0x0)
@@ -759,6 +811,8 @@ Testing: -drive if=floppy,file=TEST_DIR/t.qcow2 -drive if=none,file=TEST_DIR/t.q
                 discard_granularity = 4294967295 (4 GiB)
                 write-cache = "auto"
                 share-rw = false
+                account-invalid = "auto"
+                account-failed = "auto"
                 drive-type = "144"
 floppy0 (NODE_NAME): TEST_DIR/t.qcow2 (qcow2)
     Attached to:      /machine/unattached/device[N]
@@ -801,6 +855,8 @@ Testing: -drive if=floppy,file=TEST_DIR/t.qcow2 -drive if=none,file=TEST_DIR/t.q
                 discard_granularity = 4294967295 (4 GiB)
                 write-cache = "auto"
                 share-rw = false
+                account-invalid = "auto"
+                account-failed = "auto"
                 drive-type = "144"
               dev: floppy, id ""
                 unit = 0 (0x0)
@@ -813,6 +869,8 @@ Testing: -drive if=floppy,file=TEST_DIR/t.qcow2 -drive if=none,file=TEST_DIR/t.q
                 discard_granularity = 4294967295 (4 GiB)
                 write-cache = "auto"
                 share-rw = false
+                account-invalid = "auto"
+                account-failed = "auto"
                 drive-type = "144"
 floppy0 (NODE_NAME): TEST_DIR/t.qcow2 (qcow2)
     Attached to:      /machine/unattached/device[N]
@@ -861,6 +919,8 @@ Testing: -drive if=none,file=TEST_DIR/t.qcow2 -global floppy.drive=none0 -device
                 discard_granularity = 4294967295 (4 GiB)
                 write-cache = "auto"
                 share-rw = false
+                account-invalid = "auto"
+                account-failed = "auto"
                 drive-type = "144"
 none0 (NODE_NAME): TEST_DIR/t.qcow2 (qcow2)
     Attached to:      /machine/peripheral-anon/device[N]
@@ -928,6 +988,8 @@ Testing: -device floppy
                 discard_granularity = 4294967295 (4 GiB)
                 write-cache = "auto"
                 share-rw = false
+                account-invalid = "auto"
+                account-failed = "auto"
                 drive-type = "288"
 
 Testing: -device floppy,drive-type=120
@@ -952,6 +1014,8 @@ Testing: -device floppy,drive-type=120
                 discard_granularity = 4294967295 (4 GiB)
                 write-cache = "auto"
                 share-rw = false
+                account-invalid = "auto"
+                account-failed = "auto"
                 drive-type = "120"
 
 Testing: -device floppy,drive-type=144
@@ -976,6 +1040,8 @@ Testing: -device floppy,drive-type=144
                 discard_granularity = 4294967295 (4 GiB)
                 write-cache = "auto"
                 share-rw = false
+                account-invalid = "auto"
+                account-failed = "auto"
                 drive-type = "144"
 
 Testing: -device floppy,drive-type=288
@@ -1000,6 +1066,8 @@ Testing: -device floppy,drive-type=288
                 discard_granularity = 4294967295 (4 GiB)
                 write-cache = "auto"
                 share-rw = false
+                account-invalid = "auto"
+                account-failed = "auto"
                 drive-type = "288"
 
 
@@ -1027,6 +1095,8 @@ Testing: -drive if=none,file=TEST_DIR/t.qcow2 -device floppy,drive=none0,drive-t
                 discard_granularity = 4294967295 (4 GiB)
                 write-cache = "auto"
                 share-rw = false
+                account-invalid = "auto"
+                account-failed = "auto"
                 drive-type = "120"
 none0 (NODE_NAME): TEST_DIR/t.qcow2 (qcow2)
     Attached to:      /machine/peripheral-anon/device[N]
@@ -1064,6 +1134,8 @@ Testing: -drive if=none,file=TEST_DIR/t.qcow2 -device floppy,drive=none0,drive-t
                 discard_granularity = 4294967295 (4 GiB)
                 write-cache = "auto"
                 share-rw = false
+                account-invalid = "auto"
+                account-failed = "auto"
                 drive-type = "288"
 none0 (NODE_NAME): TEST_DIR/t.qcow2 (qcow2)
     Attached to:      /machine/peripheral-anon/device[N]
@@ -1104,6 +1176,8 @@ Testing: -drive if=none,file=TEST_DIR/t.qcow2 -device floppy,drive=none0,logical
                 discard_granularity = 4294967295 (4 GiB)
                 write-cache = "auto"
                 share-rw = false
+                account-invalid = "auto"
+                account-failed = "auto"
                 drive-type = "144"
 none0 (NODE_NAME): TEST_DIR/t.qcow2 (qcow2)
     Attached to:      /machine/peripheral-anon/device[N]
@@ -1141,6 +1215,8 @@ Testing: -drive if=none,file=TEST_DIR/t.qcow2 -device floppy,drive=none0,physica
                 discard_granularity = 4294967295 (4 GiB)
                 write-cache = "auto"
                 share-rw = false
+                account-invalid = "auto"
+                account-failed = "auto"
                 drive-type = "144"
 none0 (NODE_NAME): TEST_DIR/t.qcow2 (qcow2)
     Attached to:      /machine/peripheral-anon/device[N]

tests/qemu-iotests/227.out

@@ -188,7 +188,7 @@ Testing: -blockdev driver=null-co,read-zeroes=on,node-name=null -device virtio-b
                 ],
                 "failed_unmap_operations": 0,
                 "failed_flush_operations": 0,
-                "account_invalid": false,
+                "account_invalid": true,
                 "rd_total_time_ns": 0,
                 "invalid_unmap_operations": 0,
                 "flush_operations": 0,
@@ -198,7 +198,7 @@ Testing: -blockdev driver=null-co,read-zeroes=on,node-name=null -device virtio-b
                 "rd_bytes": 0,
                 "unmap_total_time_ns": 0,
                 "invalid_flush_operations": 0,
-                "account_failed": false,
+                "account_failed": true,
                 "rd_operations": 0,
                 "invalid_wr_operations": 0,
                 "invalid_rd_operations": 0

tests/qemu-iotests/tests/backing-file-invalidation

@@ -0,0 +1,152 @@
+#!/usr/bin/env python3
+# group: rw migration
+#
+# Migrate a VM with a BDS with backing nodes, which runs
+# bdrv_invalidate_cache(), which for qcow2 and qed triggers reading the
+# backing file string from the image header.  Check whether this
+# interferes with bdrv_backing_overridden().
+#
+# Copyright (C) 2022 Red Hat, Inc.
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+#
+
+import json
+import os
+from typing import Optional
+
+import iotests
+from iotests import qemu_img_create, qemu_img_info
+
+
+image_size = 1 * 1024 * 1024
+imgs = [os.path.join(iotests.test_dir, f'{i}.img') for i in range(0, 4)]
+
+mig_sock = os.path.join(iotests.sock_dir, 'mig.sock')
+
+
+class TestPostMigrateFilename(iotests.QMPTestCase):
+    vm_s: Optional[iotests.VM] = None
+    vm_d: Optional[iotests.VM] = None
+
+    def setUp(self) -> None:
+        # Create backing chain of three images, where the backing file strings
+        # are json:{} filenames
+        qemu_img_create('-f', iotests.imgfmt, imgs[0], str(image_size))
+        for i in range(1, 3):
+            backing = {
+                'driver': iotests.imgfmt,
+                'file': {
+                    'driver': 'file',
+                    'filename': imgs[i - 1]
+                }
+            }
+            qemu_img_create('-f', iotests.imgfmt, '-F', iotests.imgfmt,
+                            '-b', 'json:' + json.dumps(backing),
+                            imgs[i], str(image_size))
+
+    def tearDown(self) -> None:
+        if self.vm_s is not None:
+            self.vm_s.shutdown()
+        if self.vm_d is not None:
+            self.vm_d.shutdown()
+
+        for img in imgs:
+            try:
+                os.remove(img)
+            except OSError:
+                pass
+        try:
+            os.remove(mig_sock)
+        except OSError:
+            pass
+
+    def test_migration(self) -> None:
+        """
+        Migrate a VM with the backing chain created in setUp() attached.  At
+        the end of the migration process, the destination will run
+        bdrv_invalidate_cache(), which for some image formats (qcow2 and qed)
+        means the backing file string is re-read from the image header.  If
+        this overwrites bs->auto_backing_file, doing so may cause
+        bdrv_backing_overridden() to become true: The image header reports a
+        json:{} filename, but when opening it, bdrv_refresh_filename() will
+        simplify it to a plain simple filename; and when bs->auto_backing_file
+        and bs->backing->bs->filename differ, bdrv_backing_overridden() becomes
+        true.
+        If bdrv_backing_overridden() is true, the BDS will be forced to get a
+        json:{} filename, which in general is not the end of the world, but not
+        great.  Check whether that happens, i.e. whether migration changes the
+        node's filename.
+        """
+
+        blockdev = {
+            'node-name': 'node0',
+            'driver': iotests.imgfmt,
+            'file': {
+                'driver': 'file',
+                'filename': imgs[2]
+            }
+        }
+
+        self.vm_s = iotests.VM(path_suffix='a') \
+                           .add_blockdev(json.dumps(blockdev))
+        self.vm_d = iotests.VM(path_suffix='b') \
+                           .add_blockdev(json.dumps(blockdev)) \
+                           .add_incoming(f'unix:{mig_sock}')
+
+        assert self.vm_s is not None
+        assert self.vm_d is not None
+
+        self.vm_s.launch()
+        self.vm_d.launch()
+
+        pre_mig_filename = self.vm_s.node_info('node0')['file']
+
+        self.vm_s.qmp('migrate', uri=f'unix:{mig_sock}')
+
+        # Wait for migration to be done
+        self.vm_s.event_wait('STOP')
+        self.vm_d.event_wait('RESUME')
+
+        post_mig_filename = self.vm_d.node_info('node0')['file']
+
+        # Verify that the filename hasn't changed from before the migration
+        self.assertEqual(pre_mig_filename, post_mig_filename)
+
+        self.vm_s.shutdown()
+        self.vm_s = None
+
+        # For good measure, try creating an overlay and check its backing
+        # chain below.  This is how the issue was originally found.
+        result = self.vm_d.qmp('blockdev-snapshot-sync',
+                               format=iotests.imgfmt,
+                               snapshot_file=imgs[3],
+                               node_name='node0',
+                               snapshot_node_name='node0-overlay')
+        self.assert_qmp(result, 'return', {})
+
+        self.vm_d.shutdown()
+        self.vm_d = None
+
+        # Check the newly created overlay's backing chain
+        chain = qemu_img_info('--backing-chain', imgs[3])
+        for index, image in enumerate(chain):
+            self.assertEqual(image['filename'], imgs[3 - index])
+
+
+if __name__ == '__main__':
+    # These are the image formats that run their open() function from their
+    # .bdrv_co_invaliate_cache() implementations, so test them
+    iotests.main(supported_fmts=['qcow2', 'qed'],
+                 supported_protocols=['file'])

tests/qemu-iotests/tests/backing-file-invalidation.out

@@ -0,0 +1,5 @@
+.
+----------------------------------------------------------------------
+Ran 1 tests
+
+OK

tests/qtest/ide-test.c

@@ -90,6 +90,7 @@ enum {
 
 enum {
     CMD_DSM         = 0x06,
+    CMD_DIAGNOSE    = 0x90,
     CMD_READ_DMA    = 0xc8,
     CMD_WRITE_DMA   = 0xca,
     CMD_FLUSH_CACHE = 0xe7,
@@ -121,7 +122,7 @@ enum {
 static QPCIBus *pcibus = NULL;
 static QGuestAllocator guest_malloc;
 
-static char *tmp_path;
+static char *tmp_path[2];
 static char *debug_path;
 
 static QTestState *ide_test_start(const char *cmdline_fmt, ...)
@@ -310,7 +311,7 @@ static QTestState *test_bmdma_setup(void)
     qts = ide_test_start(
         "-drive file=%s,if=ide,cache=writeback,format=raw "
         "-global ide-hd.serial=%s -global ide-hd.ver=%s",
-        tmp_path, "testdisk", "version");
+        tmp_path[0], "testdisk", "version");
     qtest_irq_intercept_in(qts, "ioapic");
 
     return qts;
@@ -574,7 +575,7 @@ static void test_identify(void)
     qts = ide_test_start(
         "-drive file=%s,if=ide,cache=writeback,format=raw "
         "-global ide-hd.serial=%s -global ide-hd.ver=%s",
-        tmp_path, "testdisk", "version");
+        tmp_path[0], "testdisk", "version");
 
     dev = get_pci_device(qts, &bmdma_bar, &ide_bar);
 
@@ -614,6 +615,36 @@ static void test_identify(void)
     free_pci_device(dev);
 }
 
+static void test_diagnostic(void)
+{
+    QTestState *qts;
+    QPCIDevice *dev;
+    QPCIBar bmdma_bar, ide_bar;
+    uint8_t data;
+
+    qts = ide_test_start(
+        "-blockdev driver=file,node-name=hda,filename=%s "
+        "-blockdev driver=file,node-name=hdb,filename=%s "
+        "-device ide-hd,drive=hda,bus=ide.0,unit=0 "
+        "-device ide-hd,drive=hdb,bus=ide.0,unit=1 ",
+        tmp_path[0], tmp_path[1]);
+
+    dev = get_pci_device(qts, &bmdma_bar, &ide_bar);
+
+    /* DIAGNOSE command on device 1 */
+    qpci_io_writeb(dev, ide_bar, reg_device, DEV);
+    data = qpci_io_readb(dev, ide_bar, reg_device);
+    g_assert_cmphex(data & DEV, ==, DEV);
+    qpci_io_writeb(dev, ide_bar, reg_command, CMD_DIAGNOSE);
+
+    /* Verify that DEVICE is now 0 */
+    data = qpci_io_readb(dev, ide_bar, reg_device);
+    g_assert_cmphex(data & DEV, ==, 0);
+
+    ide_test_quit(qts);
+    free_pci_device(dev);
+}
+
 /*
  * Write sector 1 with random data to make IDE storage dirty
  * Needed for flush tests so that flushes actually go though the block layer
@@ -662,7 +693,7 @@ static void test_flush(void)
 
     qts = ide_test_start(
         "-drive file=blkdebug::%s,if=ide,cache=writeback,format=raw",
-        tmp_path);
+        tmp_path[0]);
 
     dev = get_pci_device(qts, &bmdma_bar, &ide_bar);
 
@@ -713,7 +744,7 @@ static void test_pci_retry_flush(void)
     qts = ide_test_start(
         "-drive file=blkdebug:%s:%s,if=ide,cache=writeback,format=raw,"
         "rerror=stop,werror=stop",
-        debug_path, tmp_path);
+        debug_path, tmp_path[0]);
 
     dev = get_pci_device(qts, &bmdma_bar, &ide_bar);
 
@@ -892,14 +923,14 @@ static void cdrom_pio_impl(int nblocks)
 
     /* Prepopulate the CDROM with an interesting pattern */
     generate_pattern(pattern, patt_len, ATAPI_BLOCK_SIZE);
-    fh = fopen(tmp_path, "wb+");
+    fh = fopen(tmp_path[0], "wb+");
     ret = fwrite(pattern, ATAPI_BLOCK_SIZE, patt_blocks, fh);
     g_assert_cmpint(ret, ==, patt_blocks);
     fclose(fh);
 
     qts = ide_test_start(
             "-drive if=none,file=%s,media=cdrom,format=raw,id=sr0,index=0 "
-            "-device ide-cd,drive=sr0,bus=ide.0", tmp_path);
+            "-device ide-cd,drive=sr0,bus=ide.0", tmp_path[0]);
     dev = get_pci_device(qts, &bmdma_bar, &ide_bar);
     qtest_irq_intercept_in(qts, "ioapic");
 
@@ -985,7 +1016,7 @@ static void test_cdrom_dma(void)
 
     qts = ide_test_start(
             "-drive if=none,file=%s,media=cdrom,format=raw,id=sr0,index=0 "
-            "-device ide-cd,drive=sr0,bus=ide.0", tmp_path);
+            "-device ide-cd,drive=sr0,bus=ide.0", tmp_path[0]);
     qtest_irq_intercept_in(qts, "ioapic");
 
     guest_buf = guest_alloc(&guest_malloc, len);
@@ -993,7 +1024,7 @@ static void test_cdrom_dma(void)
     prdt[0].size = cpu_to_le32(len | PRDT_EOT);
 
     generate_pattern(pattern, ATAPI_BLOCK_SIZE * 16, ATAPI_BLOCK_SIZE);
-    fh = fopen(tmp_path, "wb+");
+    fh = fopen(tmp_path[0], "wb+");
     ret = fwrite(pattern, ATAPI_BLOCK_SIZE, 16, fh);
     g_assert_cmpint(ret, ==, 16);
     fclose(fh);
@@ -1012,6 +1043,7 @@ static void test_cdrom_dma(void)
 int main(int argc, char **argv)
 {
     const char *base;
+    int i;
     int fd;
     int ret;
 
@@ -1035,18 +1067,22 @@ int main(int argc, char **argv)
     close(fd);
 
     /* Create a temporary raw image */
-    tmp_path = g_strdup_printf("%s/qtest.XXXXXX", base);
+    for (i = 0; i < 2; ++i) {
-    fd = g_mkstemp(tmp_path);
+        tmp_path[i] = g_strdup_printf("%s/qtest.XXXXXX", base);
-    g_assert(fd >= 0);
+        fd = g_mkstemp(tmp_path[i]);
-    ret = ftruncate(fd, TEST_IMAGE_SIZE);
+        g_assert(fd >= 0);
-    g_assert(ret == 0);
+        ret = ftruncate(fd, TEST_IMAGE_SIZE);
-    close(fd);
+        g_assert(ret == 0);
+        close(fd);
+    }
 
     /* Run the tests */
     g_test_init(&argc, &argv, NULL);
 
     qtest_add_func("/ide/identify", test_identify);
 
+    qtest_add_func("/ide/diagnostic", test_diagnostic);
+
     qtest_add_func("/ide/bmdma/simple_rw", test_bmdma_simple_rw);
     qtest_add_func("/ide/bmdma/trim", test_bmdma_trim);
     qtest_add_func("/ide/bmdma/various_prdts", test_bmdma_various_prdts);
@@ -1064,8 +1100,10 @@ int main(int argc, char **argv)
     ret = g_test_run();
 
     /* Cleanup */
-    unlink(tmp_path);
+    for (i = 0; i < 2; ++i) {
-    g_free(tmp_path);
+        unlink(tmp_path[i]);
+        g_free(tmp_path[i]);
+    }
     unlink(debug_path);
     g_free(debug_path);