diff --git a/block.c b/block.c
index 50dab8e595..4582961965 100644
--- a/block.c
+++ b/block.c
@@ -580,6 +580,26 @@ static int refresh_total_sectors(BlockDriverState *bs, int64_t hint)
     return 0;
 }
 
+/**
+ * Set open flags for a given discard mode
+ *
+ * Return 0 on success, -1 if the discard mode was invalid.
+ */
+int bdrv_parse_discard_flags(const char *mode, int *flags)
+{
+    *flags &= ~BDRV_O_UNMAP;
+
+    if (!strcmp(mode, "off") || !strcmp(mode, "ignore")) {
+        /* do nothing */
+    } else if (!strcmp(mode, "on") || !strcmp(mode, "unmap")) {
+        *flags |= BDRV_O_UNMAP;
+    } else {
+        return -1;
+    }
+
+    return 0;
+}
+
 /**
  * Set open flags for a given cache mode
  *
@@ -2427,6 +2447,10 @@ int bdrv_truncate(BlockDriverState *bs, int64_t offset)
         return -EACCES;
     if (bdrv_in_use(bs))
         return -EBUSY;
+
+    /* There better not be any in-flight IOs when we truncate the device. */
+    bdrv_drain_all();
+
     ret = drv->bdrv_truncate(bs, offset);
     if (ret == 0) {
         ret = refresh_total_sectors(bs, offset >> BDRV_SECTOR_BITS);
@@ -2681,6 +2705,7 @@ int bdrv_has_zero_init(BlockDriverState *bs)
 
 typedef struct BdrvCoIsAllocatedData {
     BlockDriverState *bs;
+    BlockDriverState *base;
     int64_t sector_num;
     int nb_sectors;
     int *pnum;
@@ -2813,6 +2838,44 @@ int coroutine_fn bdrv_co_is_allocated_above(BlockDriverState *top,
     return 0;
 }
 
+/* Coroutine wrapper for bdrv_is_allocated_above() */
+static void coroutine_fn bdrv_is_allocated_above_co_entry(void *opaque)
+{
+    BdrvCoIsAllocatedData *data = opaque;
+    BlockDriverState *top = data->bs;
+    BlockDriverState *base = data->base;
+
+    data->ret = bdrv_co_is_allocated_above(top, base, data->sector_num,
+                                           data->nb_sectors, data->pnum);
+    data->done = true;
+}
+
+/*
+ * Synchronous wrapper around bdrv_co_is_allocated_above().
+ *
+ * See bdrv_co_is_allocated_above() for details.
+ */
+int bdrv_is_allocated_above(BlockDriverState *top, BlockDriverState *base,
+                            int64_t sector_num, int nb_sectors, int *pnum)
+{
+    Coroutine *co;
+    BdrvCoIsAllocatedData data = {
+        .bs = top,
+        .base = base,
+        .sector_num = sector_num,
+        .nb_sectors = nb_sectors,
+        .pnum = pnum,
+        .done = false,
+    };
+
+    co = qemu_coroutine_create(bdrv_is_allocated_above_co_entry);
+    qemu_coroutine_enter(co, &data);
+    while (!data.done) {
+        qemu_aio_wait();
+    }
+    return data.ret;
+}
+
 BlockInfo *bdrv_query_info(BlockDriverState *bs)
 {
     BlockInfo *info = g_malloc0(sizeof(*info));
@@ -4148,6 +4211,11 @@ int coroutine_fn bdrv_co_discard(BlockDriverState *bs, int64_t sector_num,
         bdrv_reset_dirty(bs, sector_num, nb_sectors);
     }
 
+    /* Do nothing if disabled.  */
+    if (!(bs->open_flags & BDRV_O_UNMAP)) {
+        return 0;
+    }
+
     if (bs->drv->bdrv_co_discard) {
         return bs->drv->bdrv_co_discard(bs, sector_num, nb_sectors);
     } else if (bs->drv->bdrv_aio_discard) {
@@ -4431,7 +4499,8 @@ bdrv_acct_done(BlockDriverState *bs, BlockAcctCookie *cookie)
 
 void bdrv_img_create(const char *filename, const char *fmt,
                      const char *base_filename, const char *base_fmt,
-                     char *options, uint64_t img_size, int flags, Error **errp)
+                     char *options, uint64_t img_size, int flags,
+                     Error **errp, bool quiet)
 {
     QEMUOptionParameter *param = NULL, *create_options = NULL;
     QEMUOptionParameter *backing_fmt, *backing_file, *size;
@@ -4540,10 +4609,11 @@ void bdrv_img_create(const char *filename, const char *fmt,
         }
     }
 
-    printf("Formatting '%s', fmt=%s ", filename, fmt);
-    print_option_parameters(param);
-    puts("");
-
+    if (!quiet) {
+        printf("Formatting '%s', fmt=%s ", filename, fmt);
+        print_option_parameters(param);
+        puts("");
+    }
     ret = bdrv_create(drv, filename, param);
     if (ret < 0) {
         if (ret == -ENOTSUP) {
diff --git a/block/qcow2-refcount.c b/block/qcow2-refcount.c
index bc1784c30e..55543edf77 100644
--- a/block/qcow2-refcount.c
+++ b/block/qcow2-refcount.c
@@ -914,6 +914,12 @@ static void inc_refcounts(BlockDriverState *bs,
     }
 }
 
+/* Flags for check_refcounts_l1() and check_refcounts_l2() */
+enum {
+    CHECK_OFLAG_COPIED = 0x1,   /* check QCOW_OFLAG_COPIED matches refcount */
+    CHECK_FRAG_INFO = 0x2,      /* update BlockFragInfo counters */
+};
+
 /*
  * Increases the refcount in the given refcount table for the all clusters
  * referenced in the L2 table. While doing so, performs some checks on L2
@@ -924,10 +930,11 @@ static void inc_refcounts(BlockDriverState *bs,
  */
 static int check_refcounts_l2(BlockDriverState *bs, BdrvCheckResult *res,
     uint16_t *refcount_table, int refcount_table_size, int64_t l2_offset,
-    int check_copied)
+    int flags)
 {
     BDRVQcowState *s = bs->opaque;
     uint64_t *l2_table, l2_entry;
+    uint64_t next_contiguous_offset = 0;
     int i, l2_size, nb_csectors, refcount;
 
     /* Read L2 table from disk */
@@ -958,6 +965,18 @@ static int check_refcounts_l2(BlockDriverState *bs, BdrvCheckResult *res,
             l2_entry &= s->cluster_offset_mask;
             inc_refcounts(bs, res, refcount_table, refcount_table_size,
                 l2_entry & ~511, nb_csectors * 512);
+
+            if (flags & CHECK_FRAG_INFO) {
+                res->bfi.allocated_clusters++;
+                res->bfi.compressed_clusters++;
+
+                /* Compressed clusters are fragmented by nature.  Since they
+                 * take up sub-sector space but we only have sector granularity
+                 * I/O we need to re-read the same sectors even for adjacent
+                 * compressed clusters.
+                 */
+                res->bfi.fragmented_clusters++;
+            }
             break;
 
         case QCOW2_CLUSTER_ZERO:
@@ -971,7 +990,7 @@ static int check_refcounts_l2(BlockDriverState *bs, BdrvCheckResult *res,
             /* QCOW_OFLAG_COPIED must be set iff refcount == 1 */
             uint64_t offset = l2_entry & L2E_OFFSET_MASK;
 
-            if (check_copied) {
+            if (flags & CHECK_OFLAG_COPIED) {
                 refcount = get_refcount(bs, offset >> s->cluster_bits);
                 if (refcount < 0) {
                     fprintf(stderr, "Can't get refcount for offset %"
@@ -985,6 +1004,15 @@ static int check_refcounts_l2(BlockDriverState *bs, BdrvCheckResult *res,
                 }
             }
 
+            if (flags & CHECK_FRAG_INFO) {
+                res->bfi.allocated_clusters++;
+                if (next_contiguous_offset &&
+                    offset != next_contiguous_offset) {
+                    res->bfi.fragmented_clusters++;
+                }
+                next_contiguous_offset = offset + s->cluster_size;
+            }
+
             /* Mark cluster as used */
             inc_refcounts(bs, res, refcount_table,refcount_table_size,
                 offset, s->cluster_size);
@@ -1028,7 +1056,7 @@ static int check_refcounts_l1(BlockDriverState *bs,
                               uint16_t *refcount_table,
                               int refcount_table_size,
                               int64_t l1_table_offset, int l1_size,
-                              int check_copied)
+                              int flags)
 {
     BDRVQcowState *s = bs->opaque;
     uint64_t *l1_table, l2_offset, l1_size2;
@@ -1057,7 +1085,7 @@ static int check_refcounts_l1(BlockDriverState *bs,
         l2_offset = l1_table[i];
         if (l2_offset) {
             /* QCOW_OFLAG_COPIED must be set iff refcount == 1 */
-            if (check_copied) {
+            if (flags & CHECK_OFLAG_COPIED) {
                 refcount = get_refcount(bs, (l2_offset & ~QCOW_OFLAG_COPIED)
                     >> s->cluster_bits);
                 if (refcount < 0) {
@@ -1086,7 +1114,7 @@ static int check_refcounts_l1(BlockDriverState *bs,
 
             /* Process and check L2 entries */
             ret = check_refcounts_l2(bs, res, refcount_table,
-                refcount_table_size, l2_offset, check_copied);
+                                     refcount_table_size, l2_offset, flags);
             if (ret < 0) {
                 goto fail;
             }
@@ -1112,7 +1140,7 @@ int qcow2_check_refcounts(BlockDriverState *bs, BdrvCheckResult *res,
                           BdrvCheckMode fix)
 {
     BDRVQcowState *s = bs->opaque;
-    int64_t size, i;
+    int64_t size, i, highest_cluster;
     int nb_clusters, refcount1, refcount2;
     QCowSnapshot *sn;
     uint16_t *refcount_table;
@@ -1120,6 +1148,7 @@ int qcow2_check_refcounts(BlockDriverState *bs, BdrvCheckResult *res,
 
     size = bdrv_getlength(bs->file);
     nb_clusters = size_to_clusters(s, size);
+    res->bfi.total_clusters = nb_clusters;
     refcount_table = g_malloc0(nb_clusters * sizeof(uint16_t));
 
     /* header */
@@ -1128,7 +1157,8 @@ int qcow2_check_refcounts(BlockDriverState *bs, BdrvCheckResult *res,
 
     /* current L1 table */
     ret = check_refcounts_l1(bs, res, refcount_table, nb_clusters,
-                       s->l1_table_offset, s->l1_size, 1);
+                             s->l1_table_offset, s->l1_size,
+                             CHECK_OFLAG_COPIED | CHECK_FRAG_INFO);
     if (ret < 0) {
         goto fail;
     }
@@ -1183,7 +1213,7 @@ int qcow2_check_refcounts(BlockDriverState *bs, BdrvCheckResult *res,
     }
 
     /* compare ref counts */
-    for(i = 0; i < nb_clusters; i++) {
+    for (i = 0, highest_cluster = 0; i < nb_clusters; i++) {
         refcount1 = get_refcount(bs, i);
         if (refcount1 < 0) {
             fprintf(stderr, "Can't get refcount for cluster %" PRId64 ": %s\n",
@@ -1193,6 +1223,11 @@ int qcow2_check_refcounts(BlockDriverState *bs, BdrvCheckResult *res,
         }
 
         refcount2 = refcount_table[i];
+
+        if (refcount1 > 0 || refcount2 > 0) {
+            highest_cluster = i;
+        }
+
         if (refcount1 != refcount2) {
 
             /* Check if we're allowed to fix the mismatch */
@@ -1227,6 +1262,7 @@ int qcow2_check_refcounts(BlockDriverState *bs, BdrvCheckResult *res,
         }
     }
 
+    res->image_end_offset = (highest_cluster + 1) * s->cluster_size;
     ret = 0;
 
 fail:
diff --git a/blockdev.c b/blockdev.c
index 63e6f1eafa..0e67d06330 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -255,7 +255,7 @@ static int parse_block_error_action(const char *buf, bool is_read)
     }
 }
 
-static bool do_check_io_limits(BlockIOLimit *io_limits)
+static bool do_check_io_limits(BlockIOLimit *io_limits, Error **errp)
 {
     bool bps_flag;
     bool iops_flag;
@@ -269,6 +269,18 @@ static bool do_check_io_limits(BlockIOLimit *io_limits)
                  && ((io_limits->iops[BLOCK_IO_LIMIT_READ] != 0)
                  || (io_limits->iops[BLOCK_IO_LIMIT_WRITE] != 0));
     if (bps_flag || iops_flag) {
+        error_setg(errp, "bps(iops) and bps_rd/bps_wr(iops_rd/iops_wr) "
+                         "cannot be used at the same time");
+        return false;
+    }
+
+    if (io_limits->bps[BLOCK_IO_LIMIT_TOTAL] < 0 ||
+        io_limits->bps[BLOCK_IO_LIMIT_WRITE] < 0 ||
+        io_limits->bps[BLOCK_IO_LIMIT_READ] < 0 ||
+        io_limits->iops[BLOCK_IO_LIMIT_TOTAL] < 0 ||
+        io_limits->iops[BLOCK_IO_LIMIT_WRITE] < 0 ||
+        io_limits->iops[BLOCK_IO_LIMIT_READ] < 0) {
+        error_setg(errp, "bps and iops values must be 0 or greater");
         return false;
     }
 
@@ -297,6 +309,7 @@ DriveInfo *drive_init(QemuOpts *opts, BlockInterfaceType block_default_type)
     int snapshot = 0;
     bool copy_on_read;
     int ret;
+    Error *error = NULL;
 
     translation = BIOS_ATA_TRANSLATION_AUTO;
     media = MEDIA_DISK;
@@ -378,6 +391,13 @@ DriveInfo *drive_init(QemuOpts *opts, BlockInterfaceType block_default_type)
 	}
     }
 
+    if ((buf = qemu_opt_get(opts, "discard")) != NULL) {
+        if (bdrv_parse_discard_flags(buf, &bdrv_flags) != 0) {
+            error_report("invalid discard option");
+            return NULL;
+        }
+    }
+
     bdrv_flags |= BDRV_O_CACHE_WB;
     if ((buf = qemu_opt_get(opts, "cache")) != NULL) {
         if (bdrv_parse_cache_flags(buf, &bdrv_flags) != 0) {
@@ -427,9 +447,9 @@ DriveInfo *drive_init(QemuOpts *opts, BlockInterfaceType block_default_type)
     io_limits.iops[BLOCK_IO_LIMIT_WRITE] =
                            qemu_opt_get_number(opts, "iops_wr", 0);
 
-    if (!do_check_io_limits(&io_limits)) {
-        error_report("bps(iops) and bps_rd/bps_wr(iops_rd/iops_wr) "
-                     "cannot be used at the same time");
+    if (!do_check_io_limits(&io_limits, &error)) {
+        error_report("%s", error_get_pretty(error));
+        error_free(error);
         return NULL;
     }
 
@@ -791,7 +811,7 @@ void qmp_transaction(BlockdevActionList *dev_list, Error **errp)
             bdrv_img_create(new_image_file, format,
                             states->old_bs->filename,
                             states->old_bs->drv->format_name,
-                            NULL, -1, flags, &local_err);
+                            NULL, -1, flags, &local_err, false);
             if (error_is_set(&local_err)) {
                 error_propagate(errp, local_err);
                 goto delete_and_fail;
@@ -975,8 +995,7 @@ void qmp_block_set_io_throttle(const char *device, int64_t bps, int64_t bps_rd,
     io_limits.iops[BLOCK_IO_LIMIT_READ] = iops_rd;
     io_limits.iops[BLOCK_IO_LIMIT_WRITE]= iops_wr;
 
-    if (!do_check_io_limits(&io_limits)) {
-        error_set(errp, QERR_INVALID_PARAMETER_COMBINATION);
+    if (!do_check_io_limits(&io_limits, errp)) {
         return;
     }
 
@@ -1284,7 +1303,7 @@ void qmp_drive_mirror(const char *device, const char *target,
         /* create new image w/o backing file */
         assert(format && drv);
         bdrv_img_create(target, format,
-                        NULL, NULL, NULL, size, flags, &local_err);
+                        NULL, NULL, NULL, size, flags, &local_err, false);
     } else {
         switch (mode) {
         case NEW_IMAGE_MODE_EXISTING:
@@ -1295,7 +1314,7 @@ void qmp_drive_mirror(const char *device, const char *target,
             bdrv_img_create(target, format,
                             source->filename,
                             source->drv->format_name,
-                            NULL, size, flags, &local_err);
+                            NULL, size, flags, &local_err, false);
             break;
         default:
             abort();
@@ -1488,6 +1507,10 @@ QemuOptsList qemu_drive_opts = {
             .name = "file",
             .type = QEMU_OPT_STRING,
             .help = "disk image",
+        },{
+            .name = "discard",
+            .type = QEMU_OPT_STRING,
+            .help = "discard operation (ignore/off, unmap/on)",
         },{
             .name = "cache",
             .type = QEMU_OPT_STRING,
diff --git a/coroutine-sigaltstack.c b/coroutine-sigaltstack.c
index 1fb41c9f14..3de0bb33bd 100644
--- a/coroutine-sigaltstack.c
+++ b/coroutine-sigaltstack.c
@@ -33,15 +33,6 @@
 #include "qemu-common.h"
 #include "block/coroutine_int.h"
 
-enum {
-    /* Maximum free pool size prevents holding too many freed coroutines */
-    POOL_MAX_SIZE = 64,
-};
-
-/** Free list to speed up creation */
-static QSLIST_HEAD(, Coroutine) pool = QSLIST_HEAD_INITIALIZER(pool);
-static unsigned int pool_size;
-
 typedef struct {
     Coroutine base;
     void *stack;
@@ -85,17 +76,6 @@ static void qemu_coroutine_thread_cleanup(void *opaque)
     g_free(s);
 }
 
-static void __attribute__((destructor)) coroutine_cleanup(void)
-{
-    Coroutine *co;
-    Coroutine *tmp;
-
-    QSLIST_FOREACH_SAFE(co, &pool, pool_next, tmp) {
-        g_free(DO_UPCAST(CoroutineUContext, base, co)->stack);
-        g_free(co);
-    }
-}
-
 static void __attribute__((constructor)) coroutine_init(void)
 {
     int ret;
@@ -164,7 +144,7 @@ static void coroutine_trampoline(int signal)
     coroutine_bootstrap(self, co);
 }
 
-static Coroutine *coroutine_new(void)
+Coroutine *qemu_coroutine_new(void)
 {
     const size_t stack_size = 1 << 20;
     CoroutineUContext *co;
@@ -272,31 +252,10 @@ static Coroutine *coroutine_new(void)
     return &co->base;
 }
 
-Coroutine *qemu_coroutine_new(void)
-{
-    Coroutine *co;
-
-    co = QSLIST_FIRST(&pool);
-    if (co) {
-        QSLIST_REMOVE_HEAD(&pool, pool_next);
-        pool_size--;
-    } else {
-        co = coroutine_new();
-    }
-    return co;
-}
-
 void qemu_coroutine_delete(Coroutine *co_)
 {
     CoroutineUContext *co = DO_UPCAST(CoroutineUContext, base, co_);
 
-    if (pool_size < POOL_MAX_SIZE) {
-        QSLIST_INSERT_HEAD(&pool, &co->base, pool_next);
-        co->base.caller = NULL;
-        pool_size++;
-        return;
-    }
-
     g_free(co->stack);
     g_free(co);
 }
diff --git a/coroutine-ucontext.c b/coroutine-ucontext.c
index bd20e384b7..867a662de0 100644
--- a/coroutine-ucontext.c
+++ b/coroutine-ucontext.c
@@ -34,15 +34,6 @@
 #include <valgrind/valgrind.h>
 #endif
 
-enum {
-    /* Maximum free pool size prevents holding too many freed coroutines */
-    POOL_MAX_SIZE = 64,
-};
-
-/** Free list to speed up creation */
-static QSLIST_HEAD(, Coroutine) pool = QSLIST_HEAD_INITIALIZER(pool);
-static unsigned int pool_size;
-
 typedef struct {
     Coroutine base;
     void *stack;
@@ -96,17 +87,6 @@ static void qemu_coroutine_thread_cleanup(void *opaque)
     g_free(s);
 }
 
-static void __attribute__((destructor)) coroutine_cleanup(void)
-{
-    Coroutine *co;
-    Coroutine *tmp;
-
-    QSLIST_FOREACH_SAFE(co, &pool, pool_next, tmp) {
-        g_free(DO_UPCAST(CoroutineUContext, base, co)->stack);
-        g_free(co);
-    }
-}
-
 static void __attribute__((constructor)) coroutine_init(void)
 {
     int ret;
@@ -140,7 +120,7 @@ static void coroutine_trampoline(int i0, int i1)
     }
 }
 
-static Coroutine *coroutine_new(void)
+Coroutine *qemu_coroutine_new(void)
 {
     const size_t stack_size = 1 << 20;
     CoroutineUContext *co;
@@ -186,20 +166,6 @@ static Coroutine *coroutine_new(void)
     return &co->base;
 }
 
-Coroutine *qemu_coroutine_new(void)
-{
-    Coroutine *co;
-
-    co = QSLIST_FIRST(&pool);
-    if (co) {
-        QSLIST_REMOVE_HEAD(&pool, pool_next);
-        pool_size--;
-    } else {
-        co = coroutine_new();
-    }
-    return co;
-}
-
 #ifdef CONFIG_VALGRIND_H
 #ifdef CONFIG_PRAGMA_DIAGNOSTIC_AVAILABLE
 /* Work around an unused variable in the valgrind.h macro... */
@@ -218,13 +184,6 @@ void qemu_coroutine_delete(Coroutine *co_)
 {
     CoroutineUContext *co = DO_UPCAST(CoroutineUContext, base, co_);
 
-    if (pool_size < POOL_MAX_SIZE) {
-        QSLIST_INSERT_HEAD(&pool, &co->base, pool_next);
-        co->base.caller = NULL;
-        pool_size++;
-        return;
-    }
-
 #ifdef CONFIG_VALGRIND_H
     valgrind_stack_deregister(co);
 #endif
diff --git a/hw/block-common.h b/hw/block-common.h
index bb808f7f56..dd115320c9 100644
--- a/hw/block-common.h
+++ b/hw/block-common.h
@@ -50,7 +50,7 @@ static inline unsigned int get_physical_block_exp(BlockConf *conf)
     DEFINE_PROP_UINT32("opt_io_size", _state, _conf.opt_io_size, 0),    \
     DEFINE_PROP_INT32("bootindex", _state, _conf.bootindex, -1),        \
     DEFINE_PROP_UINT32("discard_granularity", _state, \
-                       _conf.discard_granularity, 0)
+                       _conf.discard_granularity, -1)
 
 #define DEFINE_BLOCK_CHS_PROPERTIES(_state, _conf)      \
     DEFINE_PROP_UINT32("cyls", _state, _conf.cyls, 0),  \
diff --git a/hw/ide/qdev.c b/hw/ide/qdev.c
index c436b38bcb..fd06da7003 100644
--- a/hw/ide/qdev.c
+++ b/hw/ide/qdev.c
@@ -143,7 +143,10 @@ static int ide_dev_initfn(IDEDevice *dev, IDEDriveKind kind)
     IDEBus *bus = DO_UPCAST(IDEBus, qbus, dev->qdev.parent_bus);
     IDEState *s = bus->ifs + dev->unit;
 
-    if (dev->conf.discard_granularity && dev->conf.discard_granularity != 512) {
+    if (dev->conf.discard_granularity == -1) {
+        dev->conf.discard_granularity = 512;
+    } else if (dev->conf.discard_granularity &&
+               dev->conf.discard_granularity != 512) {
         error_report("discard_granularity must be 512 for ide");
         return -1;
     }
diff --git a/hw/pc.h b/hw/pc.h
index fbcf43d717..da1b102ef1 100644
--- a/hw/pc.h
+++ b/hw/pc.h
@@ -187,4 +187,35 @@ void pc_system_firmware_init(MemoryRegion *rom_memory);
 
 int e820_add_entry(uint64_t, uint64_t, uint32_t);
 
+#define PC_COMPAT_1_4 \
+        {\
+            .driver   = "scsi-hd",\
+            .property = "discard_granularity",\
+            .value    = stringify(0),\
+	},{\
+            .driver   = "scsi-cd",\
+            .property = "discard_granularity",\
+            .value    = stringify(0),\
+	},{\
+            .driver   = "scsi-disk",\
+            .property = "discard_granularity",\
+            .value    = stringify(0),\
+	},{\
+            .driver   = "ide-hd",\
+            .property = "discard_granularity",\
+            .value    = stringify(0),\
+	},{\
+            .driver   = "ide-cd",\
+            .property = "discard_granularity",\
+            .value    = stringify(0),\
+	},{\
+            .driver   = "ide-drive",\
+            .property = "discard_granularity",\
+            .value    = stringify(0),\
+	},{\
+            .driver   = "virtio-blk-pci",\
+            .property = "discard_granularity",\
+            .value    = stringify(0),\
+	}
+
 #endif
diff --git a/hw/pc_piix.c b/hw/pc_piix.c
index 0af436cfaf..aa9cc81a2d 100644
--- a/hw/pc_piix.c
+++ b/hw/pc_piix.c
@@ -294,8 +294,8 @@ static void pc_xen_hvm_init(QEMUMachineInitArgs *args)
 }
 #endif
 
-static QEMUMachine pc_i440fx_machine_v1_4 = {
-    .name = "pc-i440fx-1.4",
+static QEMUMachine pc_i440fx_machine_v1_5 = {
+    .name = "pc-i440fx-1.5",
     .alias = "pc",
     .desc = "Standard PC (i440FX + PIIX, 1996)",
     .init = pc_init_pci,
@@ -304,7 +304,20 @@ static QEMUMachine pc_i440fx_machine_v1_4 = {
     DEFAULT_MACHINE_OPTIONS,
 };
 
+static QEMUMachine pc_i440fx_machine_v1_4 = {
+    .name = "pc-i440fx-1.4",
+    .desc = "Standard PC (i440FX + PIIX, 1996)",
+    .init = pc_init_pci,
+    .max_cpus = 255,
+    .compat_props = (GlobalProperty[]) {
+        PC_COMPAT_1_4,
+        { /* end of list */ }
+    },
+    DEFAULT_MACHINE_OPTIONS,
+};
+
 #define PC_COMPAT_1_3 \
+	PC_COMPAT_1_4, \
         {\
             .driver   = "usb-tablet",\
             .property = "usb_version",\
@@ -679,6 +692,7 @@ static QEMUMachine xenfv_machine = {
 
 static void pc_machine_init(void)
 {
+    qemu_register_machine(&pc_i440fx_machine_v1_5);
     qemu_register_machine(&pc_i440fx_machine_v1_4);
     qemu_register_machine(&pc_machine_v1_3);
     qemu_register_machine(&pc_machine_v1_2);
diff --git a/hw/pc_q35.c b/hw/pc_q35.c
index 6f5ff8dcae..e22fb9891d 100644
--- a/hw/pc_q35.c
+++ b/hw/pc_q35.c
@@ -209,8 +209,8 @@ static void pc_q35_init(QEMUMachineInitArgs *args)
     }
 }
 
-static QEMUMachine pc_q35_machine = {
-    .name = "pc-q35-1.4",
+static QEMUMachine pc_q35_machine_v1_5 = {
+    .name = "pc-q35-1.5",
     .alias = "q35",
     .desc = "Standard PC (Q35 + ICH9, 2009)",
     .init = pc_q35_init,
@@ -218,9 +218,22 @@ static QEMUMachine pc_q35_machine = {
     DEFAULT_MACHINE_OPTIONS,
 };
 
+static QEMUMachine pc_q35_machine_v1_4 = {
+    .name = "pc-q35-1.4",
+    .desc = "Standard PC (Q35 + ICH9, 2009)",
+    .init = pc_q35_init,
+    .max_cpus = 255,
+    .compat_props = (GlobalProperty[]) {
+        PC_COMPAT_1_4,
+        { /* end of list */ }
+    },
+    DEFAULT_MACHINE_OPTIONS,
+};
+
 static void pc_q35_machine_init(void)
 {
-    qemu_register_machine(&pc_q35_machine);
+    qemu_register_machine(&pc_q35_machine_v1_5);
+    qemu_register_machine(&pc_q35_machine_v1_4);
 }
 
 machine_init(pc_q35_machine_init);
diff --git a/hw/scsi-disk.c b/hw/scsi-disk.c
index 28e75bbf5b..d41158693e 100644
--- a/hw/scsi-disk.c
+++ b/hw/scsi-disk.c
@@ -41,9 +41,11 @@ do { printf("scsi-disk: " fmt , ## __VA_ARGS__); } while (0)
 #include <scsi/sg.h>
 #endif
 
-#define SCSI_DMA_BUF_SIZE    131072
-#define SCSI_MAX_INQUIRY_LEN 256
-#define SCSI_MAX_MODE_LEN    256
+#define SCSI_DMA_BUF_SIZE           131072
+#define SCSI_MAX_INQUIRY_LEN        256
+#define SCSI_MAX_MODE_LEN           256
+
+#define DEFAULT_DISCARD_GRANULARITY 4096
 
 typedef struct SCSIDiskState SCSIDiskState;
 
@@ -2059,6 +2061,11 @@ static int scsi_initfn(SCSIDevice *dev)
         return -1;
     }
 
+    if (s->qdev.conf.discard_granularity == -1) {
+        s->qdev.conf.discard_granularity =
+            MAX(s->qdev.conf.logical_block_size, DEFAULT_DISCARD_GRANULARITY);
+    }
+
     if (!s->version) {
         s->version = g_strdup(qemu_get_version());
     }
diff --git a/include/block/block.h b/include/block/block.h
index 5c3b911c1b..0f750d7da3 100644
--- a/include/block/block.h
+++ b/include/block/block.h
@@ -24,6 +24,7 @@ typedef struct BlockFragInfo {
     uint64_t allocated_clusters;
     uint64_t total_clusters;
     uint64_t fragmented_clusters;
+    uint64_t compressed_clusters;
 } BlockFragInfo;
 
 typedef struct QEMUSnapshotInfo {
@@ -83,6 +84,7 @@ typedef struct BlockDevOps {
 #define BDRV_O_INCOMING    0x0800  /* consistency hint for incoming migration */
 #define BDRV_O_CHECK       0x1000  /* open solely for consistency check */
 #define BDRV_O_ALLOW_RDWR  0x2000  /* allow reopen to change from r/o to r/w */
+#define BDRV_O_UNMAP       0x4000  /* execute guest UNMAP/TRIM operations */
 
 #define BDRV_O_CACHE_MASK  (BDRV_O_NOCACHE | BDRV_O_CACHE_WB | BDRV_O_NO_FLUSH)
 
@@ -132,6 +134,7 @@ void bdrv_swap(BlockDriverState *bs_new, BlockDriverState *bs_old);
 void bdrv_append(BlockDriverState *bs_new, BlockDriverState *bs_top);
 void bdrv_delete(BlockDriverState *bs);
 int bdrv_parse_cache_flags(const char *mode, int *flags);
+int bdrv_parse_discard_flags(const char *mode, int *flags);
 int bdrv_file_open(BlockDriverState **pbs, const char *filename, int flags);
 int bdrv_open_backing_file(BlockDriverState *bs);
 int bdrv_open(BlockDriverState *bs, const char *filename, int flags,
@@ -213,6 +216,7 @@ typedef struct BdrvCheckResult {
     int check_errors;
     int corruptions_fixed;
     int leaks_fixed;
+    int64_t image_end_offset;
     BlockFragInfo bfi;
 } BdrvCheckResult;
 
@@ -278,6 +282,8 @@ int bdrv_co_discard(BlockDriverState *bs, int64_t sector_num, int nb_sectors);
 int bdrv_has_zero_init(BlockDriverState *bs);
 int bdrv_is_allocated(BlockDriverState *bs, int64_t sector_num, int nb_sectors,
                       int *pnum);
+int bdrv_is_allocated_above(BlockDriverState *top, BlockDriverState *base,
+                            int64_t sector_num, int nb_sectors, int *pnum);
 
 void bdrv_set_on_error(BlockDriverState *bs, BlockdevOnError on_read_error,
                        BlockdevOnError on_write_error);
@@ -349,7 +355,8 @@ int bdrv_load_vmstate(BlockDriverState *bs, uint8_t *buf,
 
 void bdrv_img_create(const char *filename, const char *fmt,
                      const char *base_filename, const char *base_fmt,
-                     char *options, uint64_t img_size, int flags, Error **errp);
+                     char *options, uint64_t img_size, int flags,
+                     Error **errp, bool quiet);
 
 void bdrv_set_buffer_alignment(BlockDriverState *bs, int align);
 void *qemu_blockalign(BlockDriverState *bs, size_t size);
diff --git a/qapi-schema.json b/qapi-schema.json
index cd7ea25e4c..28b070f16b 100644
--- a/qapi-schema.json
+++ b/qapi-schema.json
@@ -244,6 +244,56 @@
            '*backing-filename': 'str', '*full-backing-filename': 'str',
            '*backing-filename-format': 'str', '*snapshots': ['SnapshotInfo'] } }
 
+##
+# @ImageCheck:
+#
+# Information about a QEMU image file check
+#
+# @filename: name of the image file checked
+#
+# @format: format of the image file checked
+#
+# @check-errors: number of unexpected errors occurred during check
+#
+# @image-end-offset: #optional offset (in bytes) where the image ends, this
+#                    field is present if the driver for the image format
+#                    supports it
+#
+# @corruptions: #optional number of corruptions found during the check if any
+#
+# @leaks: #optional number of leaks found during the check if any
+#
+# @corruptions-fixed: #optional number of corruptions fixed during the check
+#                     if any
+#
+# @leaks-fixed: #optional number of leaks fixed during the check if any
+#
+# @total-clusters: #optional total number of clusters, this field is present
+#                  if the driver for the image format supports it
+#
+# @allocated-clusters: #optional total number of allocated clusters, this
+#                      field is present if the driver for the image format
+#                      supports it
+#
+# @fragmented-clusters: #optional total number of fragmented clusters, this
+#                       field is present if the driver for the image format
+#                       supports it
+#
+# @compressed-clusters: #optional total number of compressed clusters, this
+#                       field is present if the driver for the image format
+#                       supports it
+#
+# Since: 1.4
+#
+##
+
+{ 'type': 'ImageCheck',
+  'data': {'filename': 'str', 'format': 'str', 'check-errors': 'int',
+           '*image-end-offset': 'int', '*corruptions': 'int', '*leaks': 'int',
+           '*corruptions-fixed': 'int', '*leaks-fixed': 'int',
+           '*total-clusters': 'int', '*allocated-clusters': 'int',
+           '*fragmented-clusters': 'int', '*compressed-clusters': 'int' } }
+
 ##
 # @StatusInfo:
 #
diff --git a/qemu-coroutine.c b/qemu-coroutine.c
index 0f6e268574..25a14c605d 100644
--- a/qemu-coroutine.c
+++ b/qemu-coroutine.c
@@ -17,13 +17,54 @@
 #include "block/coroutine.h"
 #include "block/coroutine_int.h"
 
+enum {
+    /* Maximum free pool size prevents holding too many freed coroutines */
+    POOL_MAX_SIZE = 64,
+};
+
+/** Free list to speed up creation */
+static QSLIST_HEAD(, Coroutine) pool = QSLIST_HEAD_INITIALIZER(pool);
+static unsigned int pool_size;
+
 Coroutine *qemu_coroutine_create(CoroutineEntry *entry)
 {
-    Coroutine *co = qemu_coroutine_new();
+    Coroutine *co;
+
+    co = QSLIST_FIRST(&pool);
+    if (co) {
+        QSLIST_REMOVE_HEAD(&pool, pool_next);
+        pool_size--;
+    } else {
+        co = qemu_coroutine_new();
+    }
+
     co->entry = entry;
     return co;
 }
 
+static void coroutine_delete(Coroutine *co)
+{
+    if (pool_size < POOL_MAX_SIZE) {
+        QSLIST_INSERT_HEAD(&pool, co, pool_next);
+        co->caller = NULL;
+        pool_size++;
+        return;
+    }
+
+    qemu_coroutine_delete(co);
+}
+
+static void __attribute__((destructor)) coroutine_cleanup(void)
+{
+    Coroutine *co;
+    Coroutine *tmp;
+
+    QSLIST_FOREACH_SAFE(co, &pool, pool_next, tmp) {
+        QSLIST_REMOVE_HEAD(&pool, pool_next);
+        qemu_coroutine_delete(co);
+    }
+}
+
 static void coroutine_swap(Coroutine *from, Coroutine *to)
 {
     CoroutineAction ret;
@@ -35,7 +76,7 @@ static void coroutine_swap(Coroutine *from, Coroutine *to)
         return;
     case COROUTINE_TERMINATE:
         trace_qemu_coroutine_terminate(to);
-        qemu_coroutine_delete(to);
+        coroutine_delete(to);
         return;
     default:
         abort();
diff --git a/qemu-img-cmds.hx b/qemu-img-cmds.hx
index a18136302d..4ca7e95655 100644
--- a/qemu-img-cmds.hx
+++ b/qemu-img-cmds.hx
@@ -10,27 +10,33 @@ STEXI
 ETEXI
 
 DEF("check", img_check,
-    "check [-f fmt] [-r [leaks | all]] filename")
+    "check [-q] [-f fmt] [--output=ofmt]  [-r [leaks | all]] filename")
 STEXI
-@item check [-f @var{fmt}] [-r [leaks | all]] @var{filename}
+@item check [-q] [-f @var{fmt}] [--output=@var{ofmt}] [-r [leaks | all]] @var{filename}
 ETEXI
 
 DEF("create", img_create,
-    "create [-f fmt] [-o options] filename [size]")
+    "create [-q] [-f fmt] [-o options] filename [size]")
 STEXI
-@item create [-f @var{fmt}] [-o @var{options}] @var{filename} [@var{size}]
+@item create [-q] [-f @var{fmt}] [-o @var{options}] @var{filename} [@var{size}]
 ETEXI
 
 DEF("commit", img_commit,
-    "commit [-f fmt] [-t cache] filename")
+    "commit [-q] [-f fmt] [-t cache] filename")
 STEXI
-@item commit [-f @var{fmt}] [-t @var{cache}] @var{filename}
+@item commit [-q] [-f @var{fmt}] [-t @var{cache}] @var{filename}
+ETEXI
+
+DEF("compare", img_compare,
+    "compare [-f fmt] [-F fmt] [-p] [-q] [-s] filename1 filename2")
+STEXI
+@item compare [-f @var{fmt}] [-F @var{fmt}] [-p] [-q] [-s] @var{filename1} @var{filename2}
 ETEXI
 
 DEF("convert", img_convert,
-    "convert [-c] [-p] [-f fmt] [-t cache] [-O output_fmt] [-o options] [-s snapshot_name] [-S sparse_size] filename [filename2 [...]] output_filename")
+    "convert [-c] [-p] [-q] [-f fmt] [-t cache] [-O output_fmt] [-o options] [-s snapshot_name] [-S sparse_size] filename [filename2 [...]] output_filename")
 STEXI
-@item convert [-c] [-p] [-f @var{fmt}] [-t @var{cache}] [-O @var{output_fmt}] [-o @var{options}] [-s @var{snapshot_name}] [-S @var{sparse_size}] @var{filename} [@var{filename2} [...]] @var{output_filename}
+@item convert [-c] [-p] [-q] [-f @var{fmt}] [-t @var{cache}] [-O @var{output_fmt}] [-o @var{options}] [-s @var{snapshot_name}] [-S @var{sparse_size}] @var{filename} [@var{filename2} [...]] @var{output_filename}
 ETEXI
 
 DEF("info", img_info,
@@ -40,20 +46,20 @@ STEXI
 ETEXI
 
 DEF("snapshot", img_snapshot,
-    "snapshot [-l | -a snapshot | -c snapshot | -d snapshot] filename")
+    "snapshot [-q] [-l | -a snapshot | -c snapshot | -d snapshot] filename")
 STEXI
-@item snapshot [-l | -a @var{snapshot} | -c @var{snapshot} | -d @var{snapshot}] @var{filename}
+@item snapshot [-q] [-l | -a @var{snapshot} | -c @var{snapshot} | -d @var{snapshot}] @var{filename}
 ETEXI
 
 DEF("rebase", img_rebase,
-    "rebase [-f fmt] [-t cache] [-p] [-u] -b backing_file [-F backing_fmt] filename")
+    "rebase [-q] [-f fmt] [-t cache] [-p] [-u] -b backing_file [-F backing_fmt] filename")
 STEXI
-@item rebase [-f @var{fmt}] [-t @var{cache}] [-p] [-u] -b @var{backing_file} [-F @var{backing_fmt}] @var{filename}
+@item rebase [-q] [-f @var{fmt}] [-t @var{cache}] [-p] [-u] -b @var{backing_file} [-F @var{backing_fmt}] @var{filename}
 ETEXI
 
 DEF("resize", img_resize,
-    "resize filename [+ | -]size")
+    "resize [-q] filename [+ | -]size")
 STEXI
-@item resize @var{filename} [+ | -]@var{size}
+@item resize [-q] @var{filename} [+ | -]@var{size}
 @end table
 ETEXI
diff --git a/qemu-img.c b/qemu-img.c
index 85d3740b9c..471de7d646 100644
--- a/qemu-img.c
+++ b/qemu-img.c
@@ -32,6 +32,7 @@
 #include "block/block_int.h"
 #include <getopt.h>
 #include <stdio.h>
+#include <stdarg.h>
 
 #ifdef _WIN32
 #include <windows.h>
@@ -42,6 +43,16 @@ typedef struct img_cmd_t {
     int (*handler)(int argc, char **argv);
 } img_cmd_t;
 
+enum {
+    OPTION_OUTPUT = 256,
+    OPTION_BACKING_CHAIN = 257,
+};
+
+typedef enum OutputFormat {
+    OFORMAT_JSON,
+    OFORMAT_HUMAN,
+} OutputFormat;
+
 /* Default to cache=writeback as data integrity is not important for qemu-tcg. */
 #define BDRV_O_FLAGS BDRV_O_CACHE_WB
 #define BDRV_DEFAULT_CACHE "writeback"
@@ -86,6 +97,7 @@ static void help(void)
            "       rebasing in this case (useful for renaming the backing file)\n"
            "  '-h' with or without a command shows this help and lists the supported formats\n"
            "  '-p' show progress of command (only certain commands)\n"
+           "  '-q' use Quiet mode - do not print any output (except errors)\n"
            "  '-S' indicates the consecutive number of bytes that must contain only zeros\n"
            "       for qemu-img to create a sparse image during conversion\n"
            "  '--output' takes the format in which the output must be done (human or json)\n"
@@ -101,7 +113,12 @@ static void help(void)
            "  '-a' applies a snapshot (revert disk to saved state)\n"
            "  '-c' creates a snapshot\n"
            "  '-d' deletes a snapshot\n"
-           "  '-l' lists all snapshots in the given image\n";
+           "  '-l' lists all snapshots in the given image\n"
+           "\n"
+           "Parameters to compare subcommand:\n"
+           "  '-f' first image format\n"
+           "  '-F' second image format\n"
+           "  '-s' run in Strict mode - fail on different image size or sector allocation\n";
 
     printf("%s\nSupported formats:", help_msg);
     bdrv_iterate_format(format_print, NULL);
@@ -109,6 +126,18 @@ static void help(void)
     exit(1);
 }
 
+static int qprintf(bool quiet, const char *fmt, ...)
+{
+    int ret = 0;
+    if (!quiet) {
+        va_list args;
+        va_start(args, fmt);
+        ret = vprintf(fmt, args);
+        va_end(args);
+    }
+    return ret;
+}
+
 #if defined(WIN32)
 /* XXX: put correct support for win32 */
 static int read_password(char *buf, int buf_size)
@@ -227,7 +256,8 @@ static int print_block_option_help(const char *filename, const char *fmt)
 static BlockDriverState *bdrv_new_open(const char *filename,
                                        const char *fmt,
                                        int flags,
-                                       bool require_io)
+                                       bool require_io,
+                                       bool quiet)
 {
     BlockDriverState *bs;
     BlockDriver *drv;
@@ -253,7 +283,7 @@ static BlockDriverState *bdrv_new_open(const char *filename,
     }
 
     if (bdrv_is_encrypted(bs) && require_io) {
-        printf("Disk image '%s' is encrypted.\n", filename);
+        qprintf(quiet, "Disk image '%s' is encrypted.\n", filename);
         if (read_password(password, sizeof(password)) < 0) {
             error_report("No password given");
             goto fail;
@@ -302,9 +332,10 @@ static int img_create(int argc, char **argv)
     const char *base_filename = NULL;
     char *options = NULL;
     Error *local_err = NULL;
+    bool quiet = false;
 
     for(;;) {
-        c = getopt(argc, argv, "F:b:f:he6o:");
+        c = getopt(argc, argv, "F:b:f:he6o:q");
         if (c == -1) {
             break;
         }
@@ -333,6 +364,9 @@ static int img_create(int argc, char **argv)
         case 'o':
             options = optarg;
             break;
+        case 'q':
+            quiet = true;
+            break;
         }
     }
 
@@ -365,7 +399,7 @@ static int img_create(int argc, char **argv)
     }
 
     bdrv_img_create(filename, fmt, base_filename, base_fmt,
-                    options, img_size, BDRV_O_FLAGS, &local_err);
+                    options, img_size, BDRV_O_FLAGS, &local_err, quiet);
     if (error_is_set(&local_err)) {
         error_report("%s", error_get_pretty(local_err));
         error_free(local_err);
@@ -375,6 +409,105 @@ static int img_create(int argc, char **argv)
     return 0;
 }
 
+static void dump_json_image_check(ImageCheck *check, bool quiet)
+{
+    Error *errp = NULL;
+    QString *str;
+    QmpOutputVisitor *ov = qmp_output_visitor_new();
+    QObject *obj;
+    visit_type_ImageCheck(qmp_output_get_visitor(ov),
+                          &check, NULL, &errp);
+    obj = qmp_output_get_qobject(ov);
+    str = qobject_to_json_pretty(obj);
+    assert(str != NULL);
+    qprintf(quiet, "%s\n", qstring_get_str(str));
+    qobject_decref(obj);
+    qmp_output_visitor_cleanup(ov);
+    QDECREF(str);
+}
+
+static void dump_human_image_check(ImageCheck *check, bool quiet)
+{
+    if (!(check->corruptions || check->leaks || check->check_errors)) {
+        qprintf(quiet, "No errors were found on the image.\n");
+    } else {
+        if (check->corruptions) {
+            qprintf(quiet, "\n%" PRId64 " errors were found on the image.\n"
+                    "Data may be corrupted, or further writes to the image "
+                    "may corrupt it.\n",
+                    check->corruptions);
+        }
+
+        if (check->leaks) {
+            qprintf(quiet,
+                    "\n%" PRId64 " leaked clusters were found on the image.\n"
+                    "This means waste of disk space, but no harm to data.\n",
+                    check->leaks);
+        }
+
+        if (check->check_errors) {
+            qprintf(quiet,
+                    "\n%" PRId64
+                    " internal errors have occurred during the check.\n",
+                    check->check_errors);
+        }
+    }
+
+    if (check->total_clusters != 0 && check->allocated_clusters != 0) {
+        qprintf(quiet, "%" PRId64 "/%" PRId64 " = %0.2f%% allocated, "
+                "%0.2f%% fragmented, %0.2f%% compressed clusters\n",
+                check->allocated_clusters, check->total_clusters,
+                check->allocated_clusters * 100.0 / check->total_clusters,
+                check->fragmented_clusters * 100.0 / check->allocated_clusters,
+                check->compressed_clusters * 100.0 /
+                check->allocated_clusters);
+    }
+
+    if (check->image_end_offset) {
+        qprintf(quiet,
+                "Image end offset: %" PRId64 "\n", check->image_end_offset);
+    }
+}
+
+static int collect_image_check(BlockDriverState *bs,
+                   ImageCheck *check,
+                   const char *filename,
+                   const char *fmt,
+                   int fix)
+{
+    int ret;
+    BdrvCheckResult result;
+
+    ret = bdrv_check(bs, &result, fix);
+    if (ret < 0) {
+        return ret;
+    }
+
+    check->filename                 = g_strdup(filename);
+    check->format                   = g_strdup(bdrv_get_format_name(bs));
+    check->check_errors             = result.check_errors;
+    check->corruptions              = result.corruptions;
+    check->has_corruptions          = result.corruptions != 0;
+    check->leaks                    = result.leaks;
+    check->has_leaks                = result.leaks != 0;
+    check->corruptions_fixed        = result.corruptions_fixed;
+    check->has_corruptions_fixed    = result.corruptions != 0;
+    check->leaks_fixed              = result.leaks_fixed;
+    check->has_leaks_fixed          = result.leaks != 0;
+    check->image_end_offset         = result.image_end_offset;
+    check->has_image_end_offset     = result.image_end_offset != 0;
+    check->total_clusters           = result.bfi.total_clusters;
+    check->has_total_clusters       = result.bfi.total_clusters != 0;
+    check->allocated_clusters       = result.bfi.allocated_clusters;
+    check->has_allocated_clusters   = result.bfi.allocated_clusters != 0;
+    check->fragmented_clusters      = result.bfi.fragmented_clusters;
+    check->has_fragmented_clusters  = result.bfi.fragmented_clusters != 0;
+    check->compressed_clusters      = result.bfi.compressed_clusters;
+    check->has_compressed_clusters  = result.bfi.compressed_clusters != 0;
+
+    return 0;
+}
+
 /*
  * Checks an image for consistency. Exit codes:
  *
@@ -386,15 +519,27 @@ static int img_create(int argc, char **argv)
 static int img_check(int argc, char **argv)
 {
     int c, ret;
-    const char *filename, *fmt;
+    OutputFormat output_format = OFORMAT_HUMAN;
+    const char *filename, *fmt, *output;
     BlockDriverState *bs;
-    BdrvCheckResult result;
     int fix = 0;
     int flags = BDRV_O_FLAGS | BDRV_O_CHECK;
+    ImageCheck *check;
+    bool quiet = false;
 
     fmt = NULL;
+    output = NULL;
     for(;;) {
-        c = getopt(argc, argv, "f:hr:");
+        int option_index = 0;
+        static const struct option long_options[] = {
+            {"help", no_argument, 0, 'h'},
+            {"format", required_argument, 0, 'f'},
+            {"repair", no_argument, 0, 'r'},
+            {"output", required_argument, 0, OPTION_OUTPUT},
+            {0, 0, 0, 0}
+        };
+        c = getopt_long(argc, argv, "f:hr:q",
+                        long_options, &option_index);
         if (c == -1) {
             break;
         }
@@ -417,6 +562,12 @@ static int img_check(int argc, char **argv)
                 help();
             }
             break;
+        case OPTION_OUTPUT:
+            output = optarg;
+            break;
+        case 'q':
+            quiet = true;
+            break;
         }
     }
     if (optind >= argc) {
@@ -424,73 +575,80 @@ static int img_check(int argc, char **argv)
     }
     filename = argv[optind++];
 
-    bs = bdrv_new_open(filename, fmt, flags, true);
+    if (output && !strcmp(output, "json")) {
+        output_format = OFORMAT_JSON;
+    } else if (output && !strcmp(output, "human")) {
+        output_format = OFORMAT_HUMAN;
+    } else if (output) {
+        error_report("--output must be used with human or json as argument.");
+        return 1;
+    }
+
+    bs = bdrv_new_open(filename, fmt, flags, true, quiet);
     if (!bs) {
         return 1;
     }
-    ret = bdrv_check(bs, &result, fix);
+
+    check = g_new0(ImageCheck, 1);
+    ret = collect_image_check(bs, check, filename, fmt, fix);
 
     if (ret == -ENOTSUP) {
-        error_report("This image format does not support checks");
-        bdrv_delete(bs);
-        return 1;
+        if (output_format == OFORMAT_HUMAN) {
+            error_report("This image format does not support checks");
+        }
+        ret = 1;
+        goto fail;
     }
 
-    if (result.corruptions_fixed || result.leaks_fixed) {
-        printf("The following inconsistencies were found and repaired:\n\n"
-               "    %d leaked clusters\n"
-               "    %d corruptions\n\n"
-               "Double checking the fixed image now...\n",
-               result.leaks_fixed,
-               result.corruptions_fixed);
-        ret = bdrv_check(bs, &result, 0);
+    if (check->corruptions_fixed || check->leaks_fixed) {
+        int corruptions_fixed, leaks_fixed;
+
+        leaks_fixed         = check->leaks_fixed;
+        corruptions_fixed   = check->corruptions_fixed;
+
+        if (output_format == OFORMAT_HUMAN) {
+            qprintf(quiet,
+                    "The following inconsistencies were found and repaired:\n\n"
+                    "    %" PRId64 " leaked clusters\n"
+                    "    %" PRId64 " corruptions\n\n"
+                    "Double checking the fixed image now...\n",
+                    check->leaks_fixed,
+                    check->corruptions_fixed);
+        }
+
+        ret = collect_image_check(bs, check, filename, fmt, 0);
+
+        check->leaks_fixed          = leaks_fixed;
+        check->corruptions_fixed    = corruptions_fixed;
     }
 
-    if (!(result.corruptions || result.leaks || result.check_errors)) {
-        printf("No errors were found on the image.\n");
+    switch (output_format) {
+    case OFORMAT_HUMAN:
+        dump_human_image_check(check, quiet);
+        break;
+    case OFORMAT_JSON:
+        dump_json_image_check(check, quiet);
+        break;
+    }
+
+    if (ret || check->check_errors) {
+        ret = 1;
+        goto fail;
+    }
+
+    if (check->corruptions) {
+        ret = 2;
+    } else if (check->leaks) {
+        ret = 3;
     } else {
-        if (result.corruptions) {
-            printf("\n%d errors were found on the image.\n"
-                "Data may be corrupted, or further writes to the image "
-                "may corrupt it.\n",
-                result.corruptions);
-        }
-
-        if (result.leaks) {
-            printf("\n%d leaked clusters were found on the image.\n"
-                "This means waste of disk space, but no harm to data.\n",
-                result.leaks);
-        }
-
-        if (result.check_errors) {
-            printf("\n%d internal errors have occurred during the check.\n",
-                result.check_errors);
-        }
-    }
-
-    if (result.bfi.total_clusters != 0 && result.bfi.allocated_clusters != 0) {
-        printf("%" PRId64 "/%" PRId64 "= %0.2f%% allocated, %0.2f%% fragmented\n",
-        result.bfi.allocated_clusters, result.bfi.total_clusters,
-        result.bfi.allocated_clusters * 100.0 / result.bfi.total_clusters,
-        result.bfi.fragmented_clusters * 100.0 / result.bfi.allocated_clusters);
+        ret = 0;
     }
 
+fail:
+    qapi_free_ImageCheck(check);
     bdrv_delete(bs);
 
-    if (ret < 0 || result.check_errors) {
-        printf("\nAn error has occurred during the check: %s\n"
-            "The check is not complete and may have missed error.\n",
-            strerror(-ret));
-        return 1;
-    }
-
-    if (result.corruptions) {
-        return 2;
-    } else if (result.leaks) {
-        return 3;
-    } else {
-        return 0;
-    }
+    return ret;
 }
 
 static int img_commit(int argc, char **argv)
@@ -498,11 +656,12 @@ static int img_commit(int argc, char **argv)
     int c, ret, flags;
     const char *filename, *fmt, *cache;
     BlockDriverState *bs;
+    bool quiet = false;
 
     fmt = NULL;
     cache = BDRV_DEFAULT_CACHE;
     for(;;) {
-        c = getopt(argc, argv, "f:ht:");
+        c = getopt(argc, argv, "f:ht:q");
         if (c == -1) {
             break;
         }
@@ -517,6 +676,9 @@ static int img_commit(int argc, char **argv)
         case 't':
             cache = optarg;
             break;
+        case 'q':
+            quiet = true;
+            break;
         }
     }
     if (optind >= argc) {
@@ -531,14 +693,14 @@ static int img_commit(int argc, char **argv)
         return -1;
     }
 
-    bs = bdrv_new_open(filename, fmt, flags, true);
+    bs = bdrv_new_open(filename, fmt, flags, true, quiet);
     if (!bs) {
         return 1;
     }
     ret = bdrv_commit(bs);
     switch(ret) {
     case 0:
-        printf("Image committed.\n");
+        qprintf(quiet, "Image committed.\n");
         break;
     case -ENOENT:
         error_report("No disk inserted");
@@ -663,6 +825,289 @@ static int compare_sectors(const uint8_t *buf1, const uint8_t *buf2, int n,
 
 #define IO_BUF_SIZE (2 * 1024 * 1024)
 
+static int64_t sectors_to_bytes(int64_t sectors)
+{
+    return sectors << BDRV_SECTOR_BITS;
+}
+
+static int64_t sectors_to_process(int64_t total, int64_t from)
+{
+    return MIN(total - from, IO_BUF_SIZE >> BDRV_SECTOR_BITS);
+}
+
+/*
+ * Check if passed sectors are empty (not allocated or contain only 0 bytes)
+ *
+ * Returns 0 in case sectors are filled with 0, 1 if sectors contain non-zero
+ * data and negative value on error.
+ *
+ * @param bs:  Driver used for accessing file
+ * @param sect_num: Number of first sector to check
+ * @param sect_count: Number of sectors to check
+ * @param filename: Name of disk file we are checking (logging purpose)
+ * @param buffer: Allocated buffer for storing read data
+ * @param quiet: Flag for quiet mode
+ */
+static int check_empty_sectors(BlockDriverState *bs, int64_t sect_num,
+                               int sect_count, const char *filename,
+                               uint8_t *buffer, bool quiet)
+{
+    int pnum, ret = 0;
+    ret = bdrv_read(bs, sect_num, buffer, sect_count);
+    if (ret < 0) {
+        error_report("Error while reading offset %" PRId64 " of %s: %s",
+                     sectors_to_bytes(sect_num), filename, strerror(-ret));
+        return ret;
+    }
+    ret = is_allocated_sectors(buffer, sect_count, &pnum);
+    if (ret || pnum != sect_count) {
+        qprintf(quiet, "Content mismatch at offset %" PRId64 "!\n",
+                sectors_to_bytes(ret ? sect_num : sect_num + pnum));
+        return 1;
+    }
+
+    return 0;
+}
+
+/*
+ * Compares two images. Exit codes:
+ *
+ * 0 - Images are identical
+ * 1 - Images differ
+ * >1 - Error occurred
+ */
+static int img_compare(int argc, char **argv)
+{
+    const char *fmt1 = NULL, *fmt2 = NULL, *filename1, *filename2;
+    BlockDriverState *bs1, *bs2;
+    int64_t total_sectors1, total_sectors2;
+    uint8_t *buf1 = NULL, *buf2 = NULL;
+    int pnum1, pnum2;
+    int allocated1, allocated2;
+    int ret = 0; /* return value - 0 Ident, 1 Different, >1 Error */
+    bool progress = false, quiet = false, strict = false;
+    int64_t total_sectors;
+    int64_t sector_num = 0;
+    int64_t nb_sectors;
+    int c, pnum;
+    uint64_t bs_sectors;
+    uint64_t progress_base;
+
+    for (;;) {
+        c = getopt(argc, argv, "hpf:F:sq");
+        if (c == -1) {
+            break;
+        }
+        switch (c) {
+        case '?':
+        case 'h':
+            help();
+            break;
+        case 'f':
+            fmt1 = optarg;
+            break;
+        case 'F':
+            fmt2 = optarg;
+            break;
+        case 'p':
+            progress = true;
+            break;
+        case 'q':
+            quiet = true;
+            break;
+        case 's':
+            strict = true;
+            break;
+        }
+    }
+
+    /* Progress is not shown in Quiet mode */
+    if (quiet) {
+        progress = false;
+    }
+
+
+    if (optind > argc - 2) {
+        help();
+    }
+    filename1 = argv[optind++];
+    filename2 = argv[optind++];
+
+    /* Initialize before goto out */
+    qemu_progress_init(progress, 2.0);
+
+    bs1 = bdrv_new_open(filename1, fmt1, BDRV_O_FLAGS, true, quiet);
+    if (!bs1) {
+        error_report("Can't open file %s", filename1);
+        ret = 2;
+        goto out3;
+    }
+
+    bs2 = bdrv_new_open(filename2, fmt2, BDRV_O_FLAGS, true, quiet);
+    if (!bs2) {
+        error_report("Can't open file %s", filename2);
+        ret = 2;
+        goto out2;
+    }
+
+    buf1 = qemu_blockalign(bs1, IO_BUF_SIZE);
+    buf2 = qemu_blockalign(bs2, IO_BUF_SIZE);
+    bdrv_get_geometry(bs1, &bs_sectors);
+    total_sectors1 = bs_sectors;
+    bdrv_get_geometry(bs2, &bs_sectors);
+    total_sectors2 = bs_sectors;
+    total_sectors = MIN(total_sectors1, total_sectors2);
+    progress_base = MAX(total_sectors1, total_sectors2);
+
+    qemu_progress_print(0, 100);
+
+    if (strict && total_sectors1 != total_sectors2) {
+        ret = 1;
+        qprintf(quiet, "Strict mode: Image size mismatch!\n");
+        goto out;
+    }
+
+    for (;;) {
+        nb_sectors = sectors_to_process(total_sectors, sector_num);
+        if (nb_sectors <= 0) {
+            break;
+        }
+        allocated1 = bdrv_is_allocated_above(bs1, NULL, sector_num, nb_sectors,
+                                             &pnum1);
+        if (allocated1 < 0) {
+            ret = 3;
+            error_report("Sector allocation test failed for %s", filename1);
+            goto out;
+        }
+
+        allocated2 = bdrv_is_allocated_above(bs2, NULL, sector_num, nb_sectors,
+                                             &pnum2);
+        if (allocated2 < 0) {
+            ret = 3;
+            error_report("Sector allocation test failed for %s", filename2);
+            goto out;
+        }
+        nb_sectors = MIN(pnum1, pnum2);
+
+        if (allocated1 == allocated2) {
+            if (allocated1) {
+                ret = bdrv_read(bs1, sector_num, buf1, nb_sectors);
+                if (ret < 0) {
+                    error_report("Error while reading offset %" PRId64 " of %s:"
+                                 " %s", sectors_to_bytes(sector_num), filename1,
+                                 strerror(-ret));
+                    ret = 4;
+                    goto out;
+                }
+                ret = bdrv_read(bs2, sector_num, buf2, nb_sectors);
+                if (ret < 0) {
+                    error_report("Error while reading offset %" PRId64
+                                 " of %s: %s", sectors_to_bytes(sector_num),
+                                 filename2, strerror(-ret));
+                    ret = 4;
+                    goto out;
+                }
+                ret = compare_sectors(buf1, buf2, nb_sectors, &pnum);
+                if (ret || pnum != nb_sectors) {
+                    ret = 1;
+                    qprintf(quiet, "Content mismatch at offset %" PRId64 "!\n",
+                            sectors_to_bytes(
+                                ret ? sector_num : sector_num + pnum));
+                    goto out;
+                }
+            }
+        } else {
+            if (strict) {
+                ret = 1;
+                qprintf(quiet, "Strict mode: Offset %" PRId64
+                        " allocation mismatch!\n",
+                        sectors_to_bytes(sector_num));
+                goto out;
+            }
+
+            if (allocated1) {
+                ret = check_empty_sectors(bs1, sector_num, nb_sectors,
+                                          filename1, buf1, quiet);
+            } else {
+                ret = check_empty_sectors(bs2, sector_num, nb_sectors,
+                                          filename2, buf1, quiet);
+            }
+            if (ret) {
+                if (ret < 0) {
+                    ret = 4;
+                    error_report("Error while reading offset %" PRId64 ": %s",
+                                 sectors_to_bytes(sector_num), strerror(-ret));
+                }
+                goto out;
+            }
+        }
+        sector_num += nb_sectors;
+        qemu_progress_print(((float) nb_sectors / progress_base)*100, 100);
+    }
+
+    if (total_sectors1 != total_sectors2) {
+        BlockDriverState *bs_over;
+        int64_t total_sectors_over;
+        const char *filename_over;
+
+        qprintf(quiet, "Warning: Image size mismatch!\n");
+        if (total_sectors1 > total_sectors2) {
+            total_sectors_over = total_sectors1;
+            bs_over = bs1;
+            filename_over = filename1;
+        } else {
+            total_sectors_over = total_sectors2;
+            bs_over = bs2;
+            filename_over = filename2;
+        }
+
+        for (;;) {
+            nb_sectors = sectors_to_process(total_sectors_over, sector_num);
+            if (nb_sectors <= 0) {
+                break;
+            }
+            ret = bdrv_is_allocated_above(bs_over, NULL, sector_num,
+                                          nb_sectors, &pnum);
+            if (ret < 0) {
+                ret = 3;
+                error_report("Sector allocation test failed for %s",
+                             filename_over);
+                goto out;
+
+            }
+            nb_sectors = pnum;
+            if (ret) {
+                ret = check_empty_sectors(bs_over, sector_num, nb_sectors,
+                                          filename_over, buf1, quiet);
+                if (ret) {
+                    if (ret < 0) {
+                        ret = 4;
+                        error_report("Error while reading offset %" PRId64
+                                     " of %s: %s", sectors_to_bytes(sector_num),
+                                     filename_over, strerror(-ret));
+                    }
+                    goto out;
+                }
+            }
+            sector_num += nb_sectors;
+            qemu_progress_print(((float) nb_sectors / progress_base)*100, 100);
+        }
+    }
+
+    qprintf(quiet, "Images are identical.\n");
+    ret = 0;
+
+out:
+    bdrv_delete(bs2);
+    qemu_vfree(buf1);
+    qemu_vfree(buf2);
+out2:
+    bdrv_delete(bs1);
+out3:
+    qemu_progress_end();
+    return ret;
+}
+
 static int img_convert(int argc, char **argv)
 {
     int c, ret = 0, n, n1, bs_n, bs_i, compress, cluster_size, cluster_sectors;
@@ -681,6 +1126,7 @@ static int img_convert(int argc, char **argv)
     const char *snapshot_name = NULL;
     float local_progress = 0;
     int min_sparse = 8; /* Need at least 4k of zeros for sparse detection */
+    bool quiet = false;
 
     fmt = NULL;
     out_fmt = "raw";
@@ -688,7 +1134,7 @@ static int img_convert(int argc, char **argv)
     out_baseimg = NULL;
     compress = 0;
     for(;;) {
-        c = getopt(argc, argv, "f:O:B:s:hce6o:pS:t:");
+        c = getopt(argc, argv, "f:O:B:s:hce6o:pS:t:q");
         if (c == -1) {
             break;
         }
@@ -742,9 +1188,16 @@ static int img_convert(int argc, char **argv)
         case 't':
             cache = optarg;
             break;
+        case 'q':
+            quiet = true;
+            break;
         }
     }
 
+    if (quiet) {
+        progress = 0;
+    }
+
     bs_n = argc - optind - 1;
     if (bs_n < 1) {
         help();
@@ -773,7 +1226,8 @@ static int img_convert(int argc, char **argv)
 
     total_sectors = 0;
     for (bs_i = 0; bs_i < bs_n; bs_i++) {
-        bs[bs_i] = bdrv_new_open(argv[optind + bs_i], fmt, BDRV_O_FLAGS, true);
+        bs[bs_i] = bdrv_new_open(argv[optind + bs_i], fmt, BDRV_O_FLAGS, true,
+                                 quiet);
         if (!bs[bs_i]) {
             error_report("Could not open '%s'", argv[optind + bs_i]);
             ret = -1;
@@ -892,7 +1346,7 @@ static int img_convert(int argc, char **argv)
         return -1;
     }
 
-    out_bs = bdrv_new_open(out_filename, out_fmt, flags, true);
+    out_bs = bdrv_new_open(out_filename, out_fmt, flags, true, quiet);
     if (!out_bs) {
         ret = -1;
         goto out;
@@ -1355,7 +1809,7 @@ static ImageInfoList *collect_image_info_list(const char *filename,
         g_hash_table_insert(filenames, (gpointer)filename, NULL);
 
         bs = bdrv_new_open(filename, fmt, BDRV_O_FLAGS | BDRV_O_NO_BACKING,
-                           false);
+                           false, false);
         if (!bs) {
             goto err;
         }
@@ -1392,16 +1846,6 @@ err:
     return NULL;
 }
 
-enum {
-    OPTION_OUTPUT = 256,
-    OPTION_BACKING_CHAIN = 257,
-};
-
-typedef enum OutputFormat {
-    OFORMAT_JSON,
-    OFORMAT_HUMAN,
-} OutputFormat;
-
 static int img_info(int argc, char **argv)
 {
     int c;
@@ -1491,11 +1935,12 @@ static int img_snapshot(int argc, char **argv)
     int c, ret = 0, bdrv_oflags;
     int action = 0;
     qemu_timeval tv;
+    bool quiet = false;
 
     bdrv_oflags = BDRV_O_FLAGS | BDRV_O_RDWR;
     /* Parse commandline parameters */
     for(;;) {
-        c = getopt(argc, argv, "la:c:d:h");
+        c = getopt(argc, argv, "la:c:d:hq");
         if (c == -1) {
             break;
         }
@@ -1536,6 +1981,9 @@ static int img_snapshot(int argc, char **argv)
             action = SNAPSHOT_DELETE;
             snapshot_name = optarg;
             break;
+        case 'q':
+            quiet = true;
+            break;
         }
     }
 
@@ -1545,7 +1993,7 @@ static int img_snapshot(int argc, char **argv)
     filename = argv[optind++];
 
     /* Open the image */
-    bs = bdrv_new_open(filename, NULL, bdrv_oflags, true);
+    bs = bdrv_new_open(filename, NULL, bdrv_oflags, true, quiet);
     if (!bs) {
         return 1;
     }
@@ -1605,6 +2053,7 @@ static int img_rebase(int argc, char **argv)
     int c, flags, ret;
     int unsafe = 0;
     int progress = 0;
+    bool quiet = false;
 
     /* Parse commandline parameters */
     fmt = NULL;
@@ -1612,7 +2061,7 @@ static int img_rebase(int argc, char **argv)
     out_baseimg = NULL;
     out_basefmt = NULL;
     for(;;) {
-        c = getopt(argc, argv, "uhf:F:b:pt:");
+        c = getopt(argc, argv, "uhf:F:b:pt:q");
         if (c == -1) {
             break;
         }
@@ -1639,9 +2088,16 @@ static int img_rebase(int argc, char **argv)
         case 't':
             cache = optarg;
             break;
+        case 'q':
+            quiet = true;
+            break;
         }
     }
 
+    if (quiet) {
+        progress = 0;
+    }
+
     if ((optind >= argc) || (!unsafe && !out_baseimg)) {
         help();
     }
@@ -1663,7 +2119,7 @@ static int img_rebase(int argc, char **argv)
      * Ignore the old backing file for unsafe rebase in case we want to correct
      * the reference to a renamed or moved backing file.
      */
-    bs = bdrv_new_open(filename, fmt, flags, true);
+    bs = bdrv_new_open(filename, fmt, flags, true, quiet);
     if (!bs) {
         return 1;
     }
@@ -1875,6 +2331,7 @@ static int img_resize(int argc, char **argv)
     int c, ret, relative;
     const char *filename, *fmt, *size;
     int64_t n, total_size;
+    bool quiet = false;
     BlockDriverState *bs = NULL;
     QemuOpts *param;
     static QemuOptsList resize_options = {
@@ -1903,7 +2360,7 @@ static int img_resize(int argc, char **argv)
     /* Parse getopt arguments */
     fmt = NULL;
     for(;;) {
-        c = getopt(argc, argv, "f:h");
+        c = getopt(argc, argv, "f:hq");
         if (c == -1) {
             break;
         }
@@ -1915,6 +2372,9 @@ static int img_resize(int argc, char **argv)
         case 'f':
             fmt = optarg;
             break;
+        case 'q':
+            quiet = true;
+            break;
         }
     }
     if (optind >= argc) {
@@ -1948,7 +2408,7 @@ static int img_resize(int argc, char **argv)
     n = qemu_opt_get_size(param, BLOCK_OPT_SIZE, 0);
     qemu_opts_del(param);
 
-    bs = bdrv_new_open(filename, fmt, BDRV_O_FLAGS | BDRV_O_RDWR, true);
+    bs = bdrv_new_open(filename, fmt, BDRV_O_FLAGS | BDRV_O_RDWR, true, quiet);
     if (!bs) {
         ret = -1;
         goto out;
@@ -1968,7 +2428,7 @@ static int img_resize(int argc, char **argv)
     ret = bdrv_truncate(bs, total_size);
     switch (ret) {
     case 0:
-        printf("Image resized.\n");
+        qprintf(quiet, "Image resized.\n");
         break;
     case -ENOTSUP:
         error_report("This image does not support resize");
diff --git a/qemu-img.texi b/qemu-img.texi
index 00fca8da86..69f1bda6ae 100644
--- a/qemu-img.texi
+++ b/qemu-img.texi
@@ -54,6 +54,9 @@ indicates that target image must be compressed (qcow format only)
 with or without a command shows help and lists the supported formats
 @item -p
 display progress bar (convert and rebase commands only)
+@item -q
+Quiet mode - do not print any output (except errors). There's no progress bar
+in case both @var{-q} and @var{-p} options are used.
 @item -S @var{size}
 indicates the consecutive number of bytes that must contain only zeros
 for qemu-img to create a sparse image during conversion. This value is rounded
@@ -81,12 +84,25 @@ deletes a snapshot
 lists all snapshots in the given image
 @end table
 
+Parameters to compare subcommand:
+
+@table @option
+
+@item -f
+First image format
+@item -F
+Second image format
+@item -s
+Strict mode - fail on on different image size or sector allocation
+@end table
+
 Command description:
 
 @table @option
-@item check [-f @var{fmt}] [-r [leaks | all]] @var{filename}
+@item check [-f @var{fmt}] [--output=@var{ofmt}] [-r [leaks | all]] @var{filename}
 
-Perform a consistency check on the disk image @var{filename}.
+Perform a consistency check on the disk image @var{filename}. The command can
+output in the format @var{ofmt} which is either @code{human} or @code{json}.
 
 If @code{-r} is specified, qemu-img tries to repair any inconsistencies found
 during the check. @code{-r leaks} repairs only cluster leaks, whereas
@@ -114,6 +130,47 @@ it doesn't need to be specified separately in this case.
 
 Commit the changes recorded in @var{filename} in its base image.
 
+@item compare [-f @var{fmt}] [-F @var{fmt}] [-p] [-s] [-q] @var{filename1} @var{filename2}
+
+Check if two images have the same content. You can compare images with
+different format or settings.
+
+The format is probed unless you specify it by @var{-f} (used for
+@var{filename1}) and/or @var{-F} (used for @var{filename2}) option.
+
+By default, images with different size are considered identical if the larger
+image contains only unallocated and/or zeroed sectors in the area after the end
+of the other image. In addition, if any sector is not allocated in one image
+and contains only zero bytes in the second one, it is evaluated as equal. You
+can use Strict mode by specifying the @var{-s} option. When compare runs in
+Strict mode, it fails in case image size differs or a sector is allocated in
+one image and is not allocated in the second one.
+
+By default, compare prints out a result message. This message displays
+information that both images are same or the position of the first different
+byte. In addition, result message can report different image size in case
+Strict mode is used.
+
+Compare exits with @code{0} in case the images are equal and with @code{1}
+in case the images differ. Other exit codes mean an error occurred during
+execution and standard error output should contain an error message.
+The following table sumarizes all exit codes of the compare subcommand:
+
+@table @option
+
+@item 0
+Images are identical
+@item 1
+Images differ
+@item 2
+Error on opening an image
+@item 3
+Error on checking a sector allocation
+@item 4
+Error on reading data
+
+@end table
+
 @item convert [-c] [-p] [-f @var{fmt}] [-t @var{cache}] [-O @var{output_fmt}] [-o @var{options}] [-s @var{snapshot_name}] [-S @var{sparse_size}] @var{filename} [@var{filename2} [...]] @var{output_filename}
 
 Convert the disk image @var{filename} or a snapshot @var{snapshot_name} to disk image @var{output_filename}
diff --git a/qemu-io.c b/qemu-io.c
index 61880932b3..7b3de42773 100644
--- a/qemu-io.c
+++ b/qemu-io.c
@@ -1899,7 +1899,7 @@ int main(int argc, char **argv)
 {
     int readonly = 0;
     int growable = 0;
-    const char *sopt = "hVc:rsnmgkt:T:";
+    const char *sopt = "hVc:d:rsnmgkt:T:";
     const struct option lopt[] = {
         { "help", 0, NULL, 'h' },
         { "version", 0, NULL, 'V' },
@@ -1911,13 +1911,14 @@ int main(int argc, char **argv)
         { "misalign", 0, NULL, 'm' },
         { "growable", 0, NULL, 'g' },
         { "native-aio", 0, NULL, 'k' },
+        { "discard", 1, NULL, 'd' },
         { "cache", 1, NULL, 't' },
         { "trace", 1, NULL, 'T' },
         { NULL, 0, NULL, 0 }
     };
     int c;
     int opt_index = 0;
-    int flags = 0;
+    int flags = BDRV_O_UNMAP;
 
     progname = basename(argv[0]);
 
@@ -1929,6 +1930,12 @@ int main(int argc, char **argv)
         case 'n':
             flags |= BDRV_O_NOCACHE | BDRV_O_CACHE_WB;
             break;
+        case 'd':
+            if (bdrv_parse_discard_flags(optarg, &flags) < 0) {
+                error_report("Invalid discard option: %s", optarg);
+                exit(1);
+            }
+            break;
         case 'c':
             add_user_command(optarg);
             break;
diff --git a/qemu-nbd.c b/qemu-nbd.c
index 0a6091b6a8..e7268d0a9f 100644
--- a/qemu-nbd.c
+++ b/qemu-nbd.c
@@ -33,9 +33,10 @@
 #include <libgen.h>
 #include <pthread.h>
 
-#define SOCKET_PATH         "/var/lock/qemu-nbd-%s"
-#define QEMU_NBD_OPT_CACHE  1
-#define QEMU_NBD_OPT_AIO    2
+#define SOCKET_PATH          "/var/lock/qemu-nbd-%s"
+#define QEMU_NBD_OPT_CACHE   1
+#define QEMU_NBD_OPT_AIO     2
+#define QEMU_NBD_OPT_DISCARD 3
 
 static NBDExport *exp;
 static int verbose;
@@ -330,6 +331,7 @@ int main(int argc, char **argv)
 #ifdef CONFIG_LINUX_AIO
         { "aio", 1, NULL, QEMU_NBD_OPT_AIO },
 #endif
+        { "discard", 1, NULL, QEMU_NBD_OPT_DISCARD },
         { "shared", 1, NULL, 'e' },
         { "persistent", 0, NULL, 't' },
         { "verbose", 0, NULL, 'v' },
@@ -344,6 +346,7 @@ int main(int argc, char **argv)
     int ret;
     int fd;
     bool seen_cache = false;
+    bool seen_discard = false;
 #ifdef CONFIG_LINUX_AIO
     bool seen_aio = false;
 #endif
@@ -389,6 +392,15 @@ int main(int argc, char **argv)
             }
             break;
 #endif
+        case QEMU_NBD_OPT_DISCARD:
+            if (seen_discard) {
+                errx(EXIT_FAILURE, "--discard can only be specified once");
+            }
+            seen_discard = true;
+            if (bdrv_parse_discard_flags(optarg, &flags) == -1) {
+                errx(EXIT_FAILURE, "Invalid discard mode `%s'", optarg);
+            }
+            break;
         case 'b':
             bindto = optarg;
             break;
diff --git a/qemu-nbd.texi b/qemu-nbd.texi
index 3e57200e76..5f3f3e3276 100644
--- a/qemu-nbd.texi
+++ b/qemu-nbd.texi
@@ -35,6 +35,10 @@ Export QEMU disk image using NBD protocol.
 @item --aio=@var{aio}
   choose asynchronous I/O mode between @samp{threads} (the default)
   and @samp{native} (Linux only).
+@item --discard=@var{discard}
+  toggles whether @dfn{discard} (also known as @dfn{trim} or @dfn{unmap})
+  requests are ignored or passed to the filesystem.  The default is no
+  (@samp{--discard=ignore}).
 @item -c, --connect=@var{dev}
   connect @var{filename} to NBD device @var{dev}
 @item -d, --disconnect
diff --git a/qemu-options.hx b/qemu-options.hx
index 2832d82148..51ff726490 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -440,6 +440,8 @@ These options have the same definition as they have in @option{-hdachs}.
 @var{cache} is "none", "writeback", "unsafe", "directsync" or "writethrough" and controls how the host cache is used to access block data.
 @item aio=@var{aio}
 @var{aio} is "threads", or "native" and selects between pthread based disk I/O and native Linux AIO.
+@item discard=@var{discard}
+@var{discard} is one of "ignore" (or "off") or "unmap" (or "on") and controls whether @dfn{discard} (also known as @dfn{trim} or @dfn{unmap}) requests are ignored or passed to the filesystem.  Some machine types may not support discard requests.
 @item format=@var{format}
 Specify which disk @var{format} will be used rather than detecting
 the format.  Can be used to specifiy format=raw to avoid interpreting
diff --git a/tests/qemu-iotests/026 b/tests/qemu-iotests/026
index 1602ccd2a5..107a3ff2f6 100755
--- a/tests/qemu-iotests/026
+++ b/tests/qemu-iotests/026
@@ -102,7 +102,7 @@ if [ "$event" == "l2_load" ]; then
     $QEMU_IO -c "read $vmstate 0 128k " $BLKDBG_TEST_IMG | _filter_qemu_io
 fi
 
-$QEMU_IMG check $TEST_IMG 2>&1 | grep -v "refcount=1 reference=0"
+_check_test_img 2>&1 | grep -v "refcount=1 reference=0"
 
 done
 done
@@ -147,7 +147,7 @@ echo
 echo "Event: $event; errno: $errno; imm: $imm; once: $once; write $vmstate"
 $QEMU_IO -c "write $vmstate 0 64M" $BLKDBG_TEST_IMG | _filter_qemu_io
 
-$QEMU_IMG check $TEST_IMG 2>&1 | grep -v "refcount=1 reference=0"
+_check_test_img 2>&1 | grep -v "refcount=1 reference=0"
 
 done
 done
@@ -186,7 +186,7 @@ echo
 echo "Event: $event; errno: $errno; imm: $imm; once: $once"
 $QEMU_IO -c "write -b 0 64k" $BLKDBG_TEST_IMG | _filter_qemu_io
 
-$QEMU_IMG check $TEST_IMG 2>&1 | grep -v "refcount=1 reference=0"
+_check_test_img 2>&1 | grep -v "refcount=1 reference=0"
 
 done
 done
diff --git a/tests/qemu-iotests/036 b/tests/qemu-iotests/036
index 329533e9ea..4dbfc5724c 100755
--- a/tests/qemu-iotests/036
+++ b/tests/qemu-iotests/036
@@ -59,7 +59,8 @@ _make_test_img 64M
 echo
 echo === Repair image ===
 echo
-$QEMU_IMG check -r all $TEST_IMG
+_check_test_img -r all
+
 ./qcow2.py $TEST_IMG dump-header
 
 # success, all done
diff --git a/tests/qemu-iotests/039 b/tests/qemu-iotests/039
index c5ae806ecb..ae3517575c 100755
--- a/tests/qemu-iotests/039
+++ b/tests/qemu-iotests/039
@@ -86,7 +86,7 @@ $QEMU_IO -r -c "read -P 0x5a 0 512" $TEST_IMG | _filter_qemu_io
 echo
 echo "== Repairing the image file must succeed =="
 
-$QEMU_IMG check -r all $TEST_IMG
+_check_test_img -r all
 
 # The dirty bit must not be set
 ./qcow2.py $TEST_IMG dump-header | grep incompatible_features
diff --git a/tests/qemu-iotests/044.out b/tests/qemu-iotests/044.out
index 7a4007137d..5eed3f87a3 100644
--- a/tests/qemu-iotests/044.out
+++ b/tests/qemu-iotests/044.out
@@ -1,4 +1,6 @@
 No errors were found on the image.
+7292415/8391499= 86.90% allocated, 0.00% fragmented, 0.00% compressed clusters
+Image end offset: 4296447488
 .
 ----------------------------------------------------------------------
 Ran 1 tests
diff --git a/tests/qemu-iotests/048 b/tests/qemu-iotests/048
new file mode 100755
index 0000000000..7cce049d2d
--- /dev/null
+++ b/tests/qemu-iotests/048
@@ -0,0 +1,78 @@
+#!/bin/bash
+##
+## qemu-img compare test
+##
+##
+## Copyright (C) 2013 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/>.
+##
+#
+# creator
+owner=mrezanin@redhat.com
+
+seq=`basename $0`
+echo "QA output created by $seq"
+
+status=1        # failure is the default!
+
+_cleanup()
+{
+    echo "Cleanup"
+    _cleanup_test_img
+    rm ${TEST_IMG2}
+}
+trap "_cleanup; exit \$status" 0 1 2 3 15
+
+_compare()
+{
+    $QEMU_IMG compare "$@" $TEST_IMG ${TEST_IMG2}
+    echo $?
+}
+
+# get standard environment, filters and checks
+. ./common.rc
+. ./common.filter
+. ./common.pattern
+
+_supported_fmt raw qcow qcow2 qed
+_supported_proto file
+_supported_os Linux
+
+# Setup test basic parameters
+TEST_IMG2=$TEST_IMG.2
+CLUSTER_SIZE=4096
+size=1024M
+
+_make_test_img $size
+io_pattern write 524288 $CLUSTER_SIZE $CLUSTER_SIZE 4 45
+
+# Compare identical images
+cp $TEST_IMG ${TEST_IMG2}
+_compare
+_compare -q
+
+# Compare images with different size
+$QEMU_IMG resize $TEST_IMG +512M
+_compare
+_compare -s
+
+# Compare images with different content
+io_pattern write 1228800 $CLUSTER_SIZE 0 1 67
+_compare
+io_pattern write 0 $CLUSTER_SIZE 0 1 123
+_compare
+
+# Cleanup
+status=0
diff --git a/tests/qemu-iotests/048.out b/tests/qemu-iotests/048.out
new file mode 100644
index 0000000000..68f65d5e19
--- /dev/null
+++ b/tests/qemu-iotests/048.out
@@ -0,0 +1,31 @@
+QA output created by 048
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=1073741824
+=== IO: pattern 45
+qemu-io> wrote 4096/4096 bytes at offset 524288
+4 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> wrote 4096/4096 bytes at offset 528384
+4 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> wrote 4096/4096 bytes at offset 532480
+4 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> wrote 4096/4096 bytes at offset 536576
+4 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> Images are identical.
+0
+0
+Image resized.
+Warning: Image size mismatch!
+Images are identical.
+0
+Strict mode: Image size mismatch!
+1
+=== IO: pattern 67
+qemu-io> wrote 4096/4096 bytes at offset 1228800
+4 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> Content mismatch at offset 1228800!
+1
+=== IO: pattern 123
+qemu-io> wrote 4096/4096 bytes at offset 0
+4 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> Content mismatch at offset 0!
+1
+Cleanup
diff --git a/tests/qemu-iotests/049 b/tests/qemu-iotests/049
new file mode 100755
index 0000000000..6c6017e2d2
--- /dev/null
+++ b/tests/qemu-iotests/049
@@ -0,0 +1,123 @@
+#!/bin/bash
+#
+# Check qemu-img option parsing
+#
+# Copyright (C) 2013 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/>.
+#
+
+# creator
+owner=kwolf@redhat.com
+
+seq=`basename $0`
+echo "QA output created by $seq"
+
+here=`pwd`
+tmp=/tmp/$$
+status=1	# failure is the default!
+
+_cleanup()
+{
+	_cleanup_test_img
+}
+trap "_cleanup; exit \$status" 0 1 2 3 15
+
+# get standard environment, filters and checks
+. ./common.rc
+. ./common.filter
+
+_supported_fmt qcow2
+_supported_proto file
+_supported_os Linux
+
+function filter_test_dir()
+{
+    sed -e "s#$IMGPROTO:$TEST_DIR#TEST_DIR#g" \
+        -e "s#$TEST_DIR#TEST_DIR#g"
+}
+
+function test_qemu_img()
+{
+    echo qemu-img "$@" | filter_test_dir
+    $QEMU_IMG "$@" 2>&1 | filter_test_dir
+    echo
+}
+
+echo "=== Check correct interpretation of suffixes for image size ==="
+echo
+sizes="1024 1024b 1k 1K 1M 1G 1T "
+sizes+="1024.0 1024.0b 1.5k 1.5K 1.5M 1.5G 1.5T"
+
+echo "== 1. Traditional size parameter =="
+echo
+for s in $sizes; do
+    test_qemu_img create -f $IMGFMT $TEST_IMG $s
+done
+
+echo "== 2. Specifying size via -o =="
+echo
+for s in $sizes; do
+    test_qemu_img create -f $IMGFMT -o size=$s $TEST_IMG
+done
+
+echo "== 3. Invalid sizes =="
+echo
+sizes="-1024 -1k 1kilobyte foobar"
+
+for s in $sizes; do
+    test_qemu_img create -f $IMGFMT $TEST_IMG -- $s
+    test_qemu_img create -f $IMGFMT -o size=$s $TEST_IMG
+done
+
+echo "== Check correct interpretation of suffixes for cluster size =="
+echo
+sizes="1024 1024b 1k 1K 1M "
+sizes+="1024.0 1024.0b 0.5k 0.5K 0.5M"
+
+for s in $sizes; do
+    test_qemu_img create -f $IMGFMT -o cluster_size=$s $TEST_IMG 64M
+done
+
+echo "== Check compat level option =="
+echo
+test_qemu_img create -f $IMGFMT -o compat=0.10 $TEST_IMG 64M
+test_qemu_img create -f $IMGFMT -o compat=1.1 $TEST_IMG 64M
+
+test_qemu_img create -f $IMGFMT -o compat=0.42 $TEST_IMG 64M
+test_qemu_img create -f $IMGFMT -o compat=foobar $TEST_IMG 64M
+
+echo "== Check preallocation option =="
+echo
+test_qemu_img create -f $IMGFMT -o preallocation=off $TEST_IMG 64M
+test_qemu_img create -f $IMGFMT -o preallocation=metadata $TEST_IMG 64M
+test_qemu_img create -f $IMGFMT -o preallocation=1234 $TEST_IMG 64M
+
+echo "== Check encryption option =="
+echo
+test_qemu_img create -f $IMGFMT -o encryption=off $TEST_IMG 64M
+test_qemu_img create -f $IMGFMT -o encryption=on $TEST_IMG 64M
+
+echo "== Check lazy_refcounts option (only with v3) =="
+echo
+test_qemu_img create -f $IMGFMT -o compat=1.1,lazy_refcounts=off $TEST_IMG 64M
+test_qemu_img create -f $IMGFMT -o compat=1.1,lazy_refcounts=on $TEST_IMG 64M
+
+test_qemu_img create -f $IMGFMT -o compat=0.10,lazy_refcounts=off $TEST_IMG 64M
+test_qemu_img create -f $IMGFMT -o compat=0.10,lazy_refcounts=on $TEST_IMG 64M
+
+# success, all done
+echo "*** done"
+rm -f $seq.full
+status=0
diff --git a/tests/qemu-iotests/049.out b/tests/qemu-iotests/049.out
new file mode 100644
index 0000000000..72db13f8d2
--- /dev/null
+++ b/tests/qemu-iotests/049.out
@@ -0,0 +1,212 @@
+QA output created by 049
+=== Check correct interpretation of suffixes for image size ===
+
+== 1. Traditional size parameter ==
+
+qemu-img create -f qcow2 TEST_DIR/t.qcow2 1024
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1024 encryption=off cluster_size=65536 lazy_refcounts=off 
+
+qemu-img create -f qcow2 TEST_DIR/t.qcow2 1024b
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1024 encryption=off cluster_size=65536 lazy_refcounts=off 
+
+qemu-img create -f qcow2 TEST_DIR/t.qcow2 1k
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1024 encryption=off cluster_size=65536 lazy_refcounts=off 
+
+qemu-img create -f qcow2 TEST_DIR/t.qcow2 1K
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1024 encryption=off cluster_size=65536 lazy_refcounts=off 
+
+qemu-img create -f qcow2 TEST_DIR/t.qcow2 1M
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1048576 encryption=off cluster_size=65536 lazy_refcounts=off 
+
+qemu-img create -f qcow2 TEST_DIR/t.qcow2 1G
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1073741824 encryption=off cluster_size=65536 lazy_refcounts=off 
+
+qemu-img create -f qcow2 TEST_DIR/t.qcow2 1T
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1099511627776 encryption=off cluster_size=65536 lazy_refcounts=off 
+
+qemu-img create -f qcow2 TEST_DIR/t.qcow2 1024.0
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1024 encryption=off cluster_size=65536 lazy_refcounts=off 
+
+qemu-img create -f qcow2 TEST_DIR/t.qcow2 1024.0b
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1024 encryption=off cluster_size=65536 lazy_refcounts=off 
+
+qemu-img create -f qcow2 TEST_DIR/t.qcow2 1.5k
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1536 encryption=off cluster_size=65536 lazy_refcounts=off 
+
+qemu-img create -f qcow2 TEST_DIR/t.qcow2 1.5K
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1536 encryption=off cluster_size=65536 lazy_refcounts=off 
+
+qemu-img create -f qcow2 TEST_DIR/t.qcow2 1.5M
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1572864 encryption=off cluster_size=65536 lazy_refcounts=off 
+
+qemu-img create -f qcow2 TEST_DIR/t.qcow2 1.5G
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1610612736 encryption=off cluster_size=65536 lazy_refcounts=off 
+
+qemu-img create -f qcow2 TEST_DIR/t.qcow2 1.5T
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1649267441664 encryption=off cluster_size=65536 lazy_refcounts=off 
+
+== 2. Specifying size via -o ==
+
+qemu-img create -f qcow2 -o size=1024 TEST_DIR/t.qcow2
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1024 encryption=off cluster_size=65536 lazy_refcounts=off 
+
+qemu-img create -f qcow2 -o size=1024b TEST_DIR/t.qcow2
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1024 encryption=off cluster_size=65536 lazy_refcounts=off 
+
+qemu-img create -f qcow2 -o size=1k TEST_DIR/t.qcow2
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1024 encryption=off cluster_size=65536 lazy_refcounts=off 
+
+qemu-img create -f qcow2 -o size=1K TEST_DIR/t.qcow2
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1024 encryption=off cluster_size=65536 lazy_refcounts=off 
+
+qemu-img create -f qcow2 -o size=1M TEST_DIR/t.qcow2
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1048576 encryption=off cluster_size=65536 lazy_refcounts=off 
+
+qemu-img create -f qcow2 -o size=1G TEST_DIR/t.qcow2
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1073741824 encryption=off cluster_size=65536 lazy_refcounts=off 
+
+qemu-img create -f qcow2 -o size=1T TEST_DIR/t.qcow2
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1099511627776 encryption=off cluster_size=65536 lazy_refcounts=off 
+
+qemu-img create -f qcow2 -o size=1024.0 TEST_DIR/t.qcow2
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1024 encryption=off cluster_size=65536 lazy_refcounts=off 
+
+qemu-img create -f qcow2 -o size=1024.0b TEST_DIR/t.qcow2
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1024 encryption=off cluster_size=65536 lazy_refcounts=off 
+
+qemu-img create -f qcow2 -o size=1.5k TEST_DIR/t.qcow2
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1536 encryption=off cluster_size=65536 lazy_refcounts=off 
+
+qemu-img create -f qcow2 -o size=1.5K TEST_DIR/t.qcow2
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1536 encryption=off cluster_size=65536 lazy_refcounts=off 
+
+qemu-img create -f qcow2 -o size=1.5M TEST_DIR/t.qcow2
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1572864 encryption=off cluster_size=65536 lazy_refcounts=off 
+
+qemu-img create -f qcow2 -o size=1.5G TEST_DIR/t.qcow2
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1610612736 encryption=off cluster_size=65536 lazy_refcounts=off 
+
+qemu-img create -f qcow2 -o size=1.5T TEST_DIR/t.qcow2
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1649267441664 encryption=off cluster_size=65536 lazy_refcounts=off 
+
+== 3. Invalid sizes ==
+
+qemu-img create -f qcow2 TEST_DIR/t.qcow2 -- -1024
+qemu-img: Image size must be less than 8 EiB!
+
+qemu-img create -f qcow2 -o size=-1024 TEST_DIR/t.qcow2
+qemu-img: qcow2 doesn't support shrinking images yet
+qemu-img: Formatting or formatting option not supported for file format 'qcow2'
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=-1024 encryption=off cluster_size=65536 lazy_refcounts=off 
+
+qemu-img create -f qcow2 TEST_DIR/t.qcow2 -- -1k
+qemu-img: Image size must be less than 8 EiB!
+
+qemu-img create -f qcow2 -o size=-1k TEST_DIR/t.qcow2
+qemu-img: qcow2 doesn't support shrinking images yet
+qemu-img: Formatting or formatting option not supported for file format 'qcow2'
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=-1024 encryption=off cluster_size=65536 lazy_refcounts=off 
+
+qemu-img create -f qcow2 TEST_DIR/t.qcow2 -- 1kilobyte
+qemu-img: Invalid image size specified! You may use k, M, G or T suffixes for 
+qemu-img: kilobytes, megabytes, gigabytes and terabytes.
+
+qemu-img create -f qcow2 -o size=1kilobyte TEST_DIR/t.qcow2
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1024 encryption=off cluster_size=65536 lazy_refcounts=off 
+
+qemu-img create -f qcow2 TEST_DIR/t.qcow2 -- foobar
+qemu-img: Invalid image size specified! You may use k, M, G or T suffixes for 
+qemu-img: kilobytes, megabytes, gigabytes and terabytes.
+
+qemu-img create -f qcow2 -o size=foobar TEST_DIR/t.qcow2
+qemu-img: Parameter 'size' expects a size
+qemu-img: Invalid options for file format 'qcow2'.
+
+== Check correct interpretation of suffixes for cluster size ==
+
+qemu-img create -f qcow2 -o cluster_size=1024 TEST_DIR/t.qcow2 64M
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 encryption=off cluster_size=1024 lazy_refcounts=off 
+
+qemu-img create -f qcow2 -o cluster_size=1024b TEST_DIR/t.qcow2 64M
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 encryption=off cluster_size=1024 lazy_refcounts=off 
+
+qemu-img create -f qcow2 -o cluster_size=1k TEST_DIR/t.qcow2 64M
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 encryption=off cluster_size=1024 lazy_refcounts=off 
+
+qemu-img create -f qcow2 -o cluster_size=1K TEST_DIR/t.qcow2 64M
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 encryption=off cluster_size=1024 lazy_refcounts=off 
+
+qemu-img create -f qcow2 -o cluster_size=1M TEST_DIR/t.qcow2 64M
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 encryption=off cluster_size=1048576 lazy_refcounts=off 
+
+qemu-img create -f qcow2 -o cluster_size=1024.0 TEST_DIR/t.qcow2 64M
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 encryption=off cluster_size=1024 lazy_refcounts=off 
+
+qemu-img create -f qcow2 -o cluster_size=1024.0b TEST_DIR/t.qcow2 64M
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 encryption=off cluster_size=1024 lazy_refcounts=off 
+
+qemu-img create -f qcow2 -o cluster_size=0.5k TEST_DIR/t.qcow2 64M
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 encryption=off cluster_size=512 lazy_refcounts=off 
+
+qemu-img create -f qcow2 -o cluster_size=0.5K TEST_DIR/t.qcow2 64M
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 encryption=off cluster_size=512 lazy_refcounts=off 
+
+qemu-img create -f qcow2 -o cluster_size=0.5M TEST_DIR/t.qcow2 64M
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 encryption=off cluster_size=524288 lazy_refcounts=off 
+
+== Check compat level option ==
+
+qemu-img create -f qcow2 -o compat=0.10 TEST_DIR/t.qcow2 64M
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 compat='0.10' encryption=off cluster_size=65536 lazy_refcounts=off 
+
+qemu-img create -f qcow2 -o compat=1.1 TEST_DIR/t.qcow2 64M
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 compat='1.1' encryption=off cluster_size=65536 lazy_refcounts=off 
+
+qemu-img create -f qcow2 -o compat=0.42 TEST_DIR/t.qcow2 64M
+Invalid compatibility level: '0.42'
+qemu-img: TEST_DIR/t.qcow2: error while creating qcow2: Invalid argument
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 compat='0.42' encryption=off cluster_size=65536 lazy_refcounts=off 
+
+qemu-img create -f qcow2 -o compat=foobar TEST_DIR/t.qcow2 64M
+Invalid compatibility level: 'foobar'
+qemu-img: TEST_DIR/t.qcow2: error while creating qcow2: Invalid argument
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 compat='foobar' encryption=off cluster_size=65536 lazy_refcounts=off 
+
+== Check preallocation option ==
+
+qemu-img create -f qcow2 -o preallocation=off TEST_DIR/t.qcow2 64M
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 encryption=off cluster_size=65536 preallocation='off' lazy_refcounts=off 
+
+qemu-img create -f qcow2 -o preallocation=metadata TEST_DIR/t.qcow2 64M
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 encryption=off cluster_size=65536 preallocation='metadata' lazy_refcounts=off 
+
+qemu-img create -f qcow2 -o preallocation=1234 TEST_DIR/t.qcow2 64M
+Invalid preallocation mode: '1234'
+qemu-img: TEST_DIR/t.qcow2: error while creating qcow2: Invalid argument
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 encryption=off cluster_size=65536 preallocation='1234' lazy_refcounts=off 
+
+== Check encryption option ==
+
+qemu-img create -f qcow2 -o encryption=off TEST_DIR/t.qcow2 64M
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 encryption=off cluster_size=65536 lazy_refcounts=off 
+
+qemu-img create -f qcow2 -o encryption=on TEST_DIR/t.qcow2 64M
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 encryption=on cluster_size=65536 lazy_refcounts=off 
+
+== Check lazy_refcounts option (only with v3) ==
+
+qemu-img create -f qcow2 -o compat=1.1,lazy_refcounts=off TEST_DIR/t.qcow2 64M
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 compat='1.1' encryption=off cluster_size=65536 lazy_refcounts=off 
+
+qemu-img create -f qcow2 -o compat=1.1,lazy_refcounts=on TEST_DIR/t.qcow2 64M
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 compat='1.1' encryption=off cluster_size=65536 lazy_refcounts=on 
+
+qemu-img create -f qcow2 -o compat=0.10,lazy_refcounts=off TEST_DIR/t.qcow2 64M
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 compat='0.10' encryption=off cluster_size=65536 lazy_refcounts=off 
+
+qemu-img create -f qcow2 -o compat=0.10,lazy_refcounts=on TEST_DIR/t.qcow2 64M
+Lazy refcounts only supported with compatibility level 1.1 and above (use compat=1.1 or greater)
+qemu-img: TEST_DIR/t.qcow2: error while creating qcow2: Invalid argument
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 compat='0.10' encryption=off cluster_size=65536 lazy_refcounts=on 
+
+*** done
diff --git a/tests/qemu-iotests/common.rc b/tests/qemu-iotests/common.rc
index aef5f52b4f..e522d617aa 100644
--- a/tests/qemu-iotests/common.rc
+++ b/tests/qemu-iotests/common.rc
@@ -161,9 +161,10 @@ _cleanup_test_img()
 
 _check_test_img()
 {
-    $QEMU_IMG check -f $IMGFMT $TEST_IMG 2>&1 | \
-        grep -v "fragmented$" | \
-    	sed -e 's/qemu-img\: This image format does not support checks/No errors were found on the image./'
+    $QEMU_IMG check "$@" -f $IMGFMT $TEST_IMG 2>&1 | \
+        sed -e '/allocated.*fragmented.*compressed clusters/d' \
+            -e 's/qemu-img: This image format does not support checks/No errors were found on the image./' \
+            -e '/Image end offset: [0-9]\+/d'
 }
 
 _img_info()
diff --git a/tests/qemu-iotests/group b/tests/qemu-iotests/group
index 1bbd2bf929..fcf57e0510 100644
--- a/tests/qemu-iotests/group
+++ b/tests/qemu-iotests/group
@@ -54,3 +54,5 @@
 045 rw auto
 046 rw auto aio
 047 rw auto
+048 img auto quick
+049 rw auto
diff --git a/tests/test-coroutine.c b/tests/test-coroutine.c
index 4c6cc81fb9..39be046ec7 100644
--- a/tests/test-coroutine.c
+++ b/tests/test-coroutine.c
@@ -183,7 +183,7 @@ static void perf_nesting(void)
     double duration;
 
     maxcycles = 100000000;
-    maxnesting = 20000;
+    maxnesting = 1000;
     Coroutine *root;
     NestData nd = {
         .n_enter  = 0,