Clear QEMU eventfd handler to prevent crashes on attach/detach

debian/changelog

@@ -1,3 +1,9 @@
+pve-qemu-kvm (5.2.0-11+vitastor5) buster; urgency=medium
+
+  * Clear QEMU eventfd handler to prevent crashes on attach/detach
+
+ -- Vitaliy Filippov <vitalif@yourcmc.ru>  Sat, 22 Mar 2025 15:09:34 +0300
+
 pve-qemu-kvm (5.2.0-11+vitastor4) buster; urgency=medium
 
   * Fix truncation

debian/patches/pve-qemu-5.2-vitastor.patch

@@ -183,7 +183,7 @@ Index: a/block/vitastor.c
 ===================================================================
 --- /dev/null
 +++ a/block/vitastor.c
-@@ -0,0 +1,1075 @@
+@@ -0,0 +1,1105 @@
 +// Copyright (c) Vitaliy Filippov, 2019+
 +// License: VNPL-1.1 or GNU GPL-2.0+ (see README.md for details)
 +
@@ -202,7 +202,6 @@ Index: a/block/vitastor.c
 +#include "qapi/error.h"
 +#include "qapi/qmp/qdict.h"
 +#include "qapi/qmp/qerror.h"
-+#include "qemu/uri.h"
 +#include "qemu/error-report.h"
 +#include "qemu/module.h"
 +#include "qemu/option.h"
@@ -382,10 +381,11 @@ Index: a/block/vitastor.c
 +            !strcmp(name, "rdma-gid-index") ||
 +            !strcmp(name, "rdma-mtu"))
 +        {
-+            unsigned long long num_val;
 +#if QEMU_VERSION_MAJOR < 8 || QEMU_VERSION_MAJOR == 8 && QEMU_VERSION_MINOR < 1
++            unsigned long long num_val;
 +            if (parse_uint_full(value, &num_val, 0))
 +#else
++            uint64_t num_val;
 +            if (parse_uint_full(value, 0, &num_val))
 +#endif
 +            {
@@ -480,7 +480,9 @@ Index: a/block/vitastor.c
 +
 +    qemu_mutex_lock(&client->mutex);
 +    vitastor_c_watch_inode(client->proxy, client->image, vitastor_co_generic_cb, task);
++#if !defined VITASTOR_C_API_VERSION || VITASTOR_C_API_VERSION < 5
 +    vitastor_schedule_uring_handler(client);
++#endif
 +    qemu_mutex_unlock(&client->mutex);
 +
 +    while (!task->complete)
@@ -752,6 +754,22 @@ Index: a/block/vitastor.c
 +static void vitastor_close(BlockDriverState *bs)
 +{
 +    VitastorClient *client = bs->opaque;
++    if (client->uring_eventfd >= 0)
++    {
++        // clear the eventfd handler
++        universal_aio_set_fd_handler(client->ctx, client->uring_eventfd, NULL, NULL, NULL);
++        int wait_bh = 0;
++        qemu_mutex_lock(&client->mutex);
++        // clear uring_eventfd itself to prevent future scheduling of new B/H
++        client->uring_eventfd = -1;
++        wait_bh = client->bh_uring_scheduled;
++        qemu_mutex_unlock(&client->mutex);
++        if (wait_bh)
++        {
++            // wait until existing scheduled B/H is ran
++            BDRV_POLL_WHILE(bs, client->bh_uring_scheduled);
++        }
++    }
 +    vitastor_c_destroy(client->proxy);
 +    if (client->fds)
 +    {
@@ -935,7 +953,9 @@ Index: a/block/vitastor.c
 +    uint64_t inode = client->watch ? vitastor_c_inode_get_num(client->watch) : client->inode;
 +    qemu_mutex_lock(&client->mutex);
 +    vitastor_c_read(client->proxy, inode, offset, bytes, iov->iov, iov->niov, vitastor_co_read_cb, &task);
++#if !defined VITASTOR_C_API_VERSION || VITASTOR_C_API_VERSION < 5
 +    vitastor_schedule_uring_handler(client);
++#endif
 +    qemu_mutex_unlock(&client->mutex);
 +
 +    while (!task.complete)
@@ -969,7 +989,9 @@ Index: a/block/vitastor.c
 +    uint64_t inode = client->watch ? vitastor_c_inode_get_num(client->watch) : client->inode;
 +    qemu_mutex_lock(&client->mutex);
 +    vitastor_c_write(client->proxy, inode, offset, bytes, 0, iov->iov, iov->niov, vitastor_co_generic_cb, &task);
++#if !defined VITASTOR_C_API_VERSION || VITASTOR_C_API_VERSION < 5
 +    vitastor_schedule_uring_handler(client);
++#endif
 +    qemu_mutex_unlock(&client->mutex);
 +
 +    while (!task.complete)
@@ -1049,7 +1071,9 @@ Index: a/block/vitastor.c
 +        task.bitmap = client->last_bitmap = NULL;
 +        qemu_mutex_lock(&client->mutex);
 +        vitastor_c_read_bitmap(client->proxy, task.inode, task.offset, task.len, !client->skip_parents, vitastor_co_read_bitmap_cb, &task);
++#if !defined VITASTOR_C_API_VERSION || VITASTOR_C_API_VERSION < 5
 +        vitastor_schedule_uring_handler(client);
++#endif
 +        qemu_mutex_unlock(&client->mutex);
 +        while (!task.complete)
 +        {
@@ -1136,7 +1160,9 @@ Index: a/block/vitastor.c
 +
 +    qemu_mutex_lock(&client->mutex);
 +    vitastor_c_sync(client->proxy, vitastor_co_generic_cb, &task);
++#if !defined VITASTOR_C_API_VERSION || VITASTOR_C_API_VERSION < 5
 +    vitastor_schedule_uring_handler(client);
++#endif
 +    qemu_mutex_unlock(&client->mutex);
 +
 +    while (!task.complete)
@@ -1206,7 +1232,11 @@ Index: a/block/vitastor.c
 +    // FIXME: Implement it along with per-inode statistics
 +    //.bdrv_get_allocated_file_size   = vitastor_get_allocated_file_size,
 +
++#if QEMU_VERSION_MAJOR > 9 || QEMU_VERSION_MAJOR == 9 && QEMU_VERSION_MINOR > 0
++    .bdrv_open                      = vitastor_file_open,
++#else
 +    .bdrv_file_open                 = vitastor_file_open,
++#endif
 +    .bdrv_close                     = vitastor_close,
 +
 +    // Option list for the create operation