diff --git a/block/accounting.c b/block/accounting.c
index 8d41c8a83a..3002444fa5 100644
--- a/block/accounting.c
+++ b/block/accounting.c
@@ -27,7 +27,9 @@
 #include "block/accounting.h"
 #include "block/block_int.h"
 #include "qemu/timer.h"
+#include "qemu/log.h"
 #include "sysemu/qtest.h"
+#include "sysemu/block-backend.h"
 
 static QEMUClockType clock_type = QEMU_CLOCK_REALTIME;
 static const int qtest_latency_ns = NANOSECONDS_PER_SECOND / 1000;
@@ -41,10 +43,11 @@ void block_acct_init(BlockAcctStats *stats)
 }
 
 void block_acct_setup(BlockAcctStats *stats, bool account_invalid,
-                      bool account_failed)
+                      bool account_failed, unsigned latency_log_threshold_ms)
 {
     stats->account_invalid = account_invalid;
     stats->account_failed = account_failed;
+    stats->latency_log_threshold_ms = latency_log_threshold_ms;
 }
 
 void block_acct_cleanup(BlockAcctStats *stats)
@@ -182,6 +185,58 @@ void block_latency_histograms_clear(BlockAcctStats *stats)
     }
 }
 
+static const char *block_account_type(enum BlockAcctType type)
+{
+    switch (type) {
+    case BLOCK_ACCT_READ:
+        return "READ";
+    case BLOCK_ACCT_WRITE:
+        return "WRITE";
+    case BLOCK_ACCT_FLUSH:
+        return "DISCARD";
+    case BLOCK_ACCT_UNMAP:
+        return "TRUNCATE";
+    case BLOCK_ACCT_NONE:
+        return "NONE";
+    case BLOCK_MAX_IOTYPE:
+        break;
+    }
+    return "UNKNOWN";
+}
+
+static void block_acct_report_long(BlockAcctStats *stats,
+                                   BlockAcctCookie *cookie, int64_t latency_ns)
+{
+    unsigned latency_ms = latency_ns / 1000000;
+    int64_t start_time_host_s;
+    char buf[64];
+    struct tm t;
+    BlockDriverState *bs;
+
+    if (cookie->type == BLOCK_ACCT_NONE) {
+        return;
+    }
+    if (stats->latency_log_threshold_ms == 0) {
+        return;
+    }
+    if (latency_ms < stats->latency_log_threshold_ms) {
+        return;
+    }
+
+    start_time_host_s = cookie->start_time_ns / 1000000000ull;
+    strftime(buf, sizeof(buf), "%m-%d %H:%M:%S",
+             localtime_r(&start_time_host_s, &t));
+
+    bs = blk_bs(blk_stats2blk(stats));
+    qemu_log("long %s[%ld] IO request: %d.03%d since %s.%03d bs: %s(%s, %s)\n",
+             block_account_type(cookie->type), cookie->bytes,
+             (int)(latency_ms / 1000), (int)(latency_ms % 1000), buf,
+             (int)((cookie->start_time_ns / 1000000) % 1000),
+             bs == NULL ? "unknown" : bdrv_get_node_name(bs),
+             bs == NULL ? "unknown" : bdrv_get_format_name(bs),
+             bs == NULL ? "unknown" : bs->filename);
+}
+
 static void block_account_one_io(BlockAcctStats *stats, BlockAcctCookie *cookie,
                                  bool failed)
 {
@@ -222,6 +277,8 @@ static void block_account_one_io(BlockAcctStats *stats, BlockAcctCookie *cookie,
 
     qemu_mutex_unlock(&stats->lock);
 
+    block_acct_report_long(stats, cookie, latency_ns);
+
     cookie->type = BLOCK_ACCT_NONE;
 }
 
diff --git a/blockdev.c b/blockdev.c
index 31d5eaf6bf..d87260958c 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -625,7 +625,8 @@ static BlockBackend *blockdev_init(const char *file, QDict *bs_opts,
 
         bs->detect_zeroes = detect_zeroes;
 
-        block_acct_setup(blk_get_stats(blk), account_invalid, account_failed);
+        block_acct_setup(blk_get_stats(blk), account_invalid, account_failed,
+                qemu_opt_get_number(opts, "latency-log-threshold", 0));
 
         if (!parse_stats_intervals(blk_get_stats(blk), interval_list, errp)) {
             blk_unref(blk);
@@ -3740,6 +3741,10 @@ QemuOptsList qemu_common_drive_opts = {
             .type = QEMU_OPT_BOOL,
             .help = "whether to account for failed I/O operations "
                     "in the statistics",
+        },{
+            .name = "latency-log-threshold",
+            .type = QEMU_OPT_STRING,
+            .help = "threshold for long I/O report (disabled if <=0), in ms",
         },
         { /* end of list */ }
     },
diff --git a/include/block/accounting.h b/include/block/accounting.h
index 878b4c3581..c3ea25f9aa 100644
--- a/include/block/accounting.h
+++ b/include/block/accounting.h
@@ -91,6 +91,9 @@ struct BlockAcctStats {
     bool account_invalid;
     bool account_failed;
     BlockLatencyHistogram latency_histogram[BLOCK_MAX_IOTYPE];
+
+    /* Threshold for long I/O detection, ms */
+    unsigned latency_log_threshold_ms;
 };
 
 typedef struct BlockAcctCookie {
@@ -101,7 +104,7 @@ typedef struct BlockAcctCookie {
 
 void block_acct_init(BlockAcctStats *stats);
 void block_acct_setup(BlockAcctStats *stats, bool account_invalid,
-                     bool account_failed);
+                      bool account_failed, unsigned latency_log_threshold_ms);
 void block_acct_cleanup(BlockAcctStats *stats);
 void block_acct_add_interval(BlockAcctStats *stats, unsigned interval_length);
 BlockAcctTimedStats *block_acct_interval_next(BlockAcctStats *stats,
