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pve-qemu-qoup/debian/patches/pve/0041-PVE-Use-non-recursive-locks.patch
Thomas Lamprecht b7e851a529 rebase patches onto v5.0.0-rc3 
Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>
2020-04-16 15:19:31 +02:00

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From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Stefan Reiter <s.reiter@proxmox.com>
Date: Thu, 16 Apr 2020 11:40:16 +0200
Subject: [PATCH] PVE: Use non-recursive locks
Release the lock on qemu_coroutine_yield, so coroutines don't deadlock.
Signed-off-by: Stefan Reiter <s.reiter@proxmox.com>
---
pve-backup.c | 82 +++++++++++++++++++++++++++-------------------------
vma-writer.c | 28 ++++++++++++++----
vma.h | 1 +
3 files changed, 66 insertions(+), 45 deletions(-)
diff --git a/pve-backup.c b/pve-backup.c
index 169f0c68d0..46a3d6f995 100644
--- a/pve-backup.c
+++ b/pve-backup.c
@@ -14,7 +14,7 @@
static struct PVEBackupState {
struct {
// Everithing accessed from qmp_backup_query command is protected using lock
- QemuRecMutex lock;
+ QemuMutex lock;
Error *error;
time_t start_time;
time_t end_time;
@@ -29,13 +29,13 @@ static struct PVEBackupState {
VmaWriter *vmaw;
ProxmoxBackupHandle *pbs;
GList *di_list;
- QemuRecMutex backup_mutex;
+ QemuMutex backup_mutex;
} backup_state;
static void pvebackup_init(void)
{
- qemu_rec_mutex_init(&backup_state.stat.lock);
- qemu_rec_mutex_init(&backup_state.backup_mutex);
+ qemu_mutex_init(&backup_state.stat.lock);
+ qemu_mutex_init(&backup_state.backup_mutex);
}
// initialize PVEBackupState at startup
@@ -72,26 +72,26 @@ lookup_active_block_job(PVEBackupDevInfo *di)
static void pvebackup_propagate_error(Error *err)
{
- qemu_rec_mutex_lock(&backup_state.stat.lock);
+ qemu_mutex_lock(&backup_state.stat.lock);
error_propagate(&backup_state.stat.error, err);
- qemu_rec_mutex_unlock(&backup_state.stat.lock);
+ qemu_mutex_unlock(&backup_state.stat.lock);
}
static bool pvebackup_error_or_canceled(void)
{
- qemu_rec_mutex_lock(&backup_state.stat.lock);
+ qemu_mutex_lock(&backup_state.stat.lock);
bool error_or_canceled = !!backup_state.stat.error;
- qemu_rec_mutex_unlock(&backup_state.stat.lock);
+ qemu_mutex_unlock(&backup_state.stat.lock);
return error_or_canceled;
}
static void pvebackup_add_transfered_bytes(size_t transferred, size_t zero_bytes)
{
- qemu_rec_mutex_lock(&backup_state.stat.lock);
+ qemu_mutex_lock(&backup_state.stat.lock);
backup_state.stat.zero_bytes += zero_bytes;
backup_state.stat.transferred += transferred;
- qemu_rec_mutex_unlock(&backup_state.stat.lock);
+ qemu_mutex_unlock(&backup_state.stat.lock);
}
// This may get called from multiple coroutines in multiple io-threads
@@ -114,16 +114,16 @@ pvebackup_co_dump_pbs_cb(
Error *local_err = NULL;
int pbs_res = -1;
- qemu_rec_mutex_lock(&backup_state.backup_mutex);
+ qemu_mutex_lock(&backup_state.backup_mutex);
// avoid deadlock if job is cancelled
if (pvebackup_error_or_canceled()) {
- qemu_rec_mutex_unlock(&backup_state.backup_mutex);
+ qemu_mutex_unlock(&backup_state.backup_mutex);
return -1;
}
pbs_res = proxmox_backup_co_write_data(backup_state.pbs, di->dev_id, buf, start, size, &local_err);
- qemu_rec_mutex_unlock(&backup_state.backup_mutex);
+ qemu_mutex_unlock(&backup_state.backup_mutex);
if (pbs_res < 0) {
pvebackup_propagate_error(local_err);
@@ -167,16 +167,16 @@ pvebackup_co_dump_vma_cb(
}
while (remaining > 0) {
- qemu_rec_mutex_lock(&backup_state.backup_mutex);
+ qemu_mutex_lock(&backup_state.backup_mutex);
// avoid deadlock if job is cancelled
if (pvebackup_error_or_canceled()) {
- qemu_rec_mutex_unlock(&backup_state.backup_mutex);
+ qemu_mutex_unlock(&backup_state.backup_mutex);
return -1;
}
size_t zero_bytes = 0;
ret = vma_writer_write(backup_state.vmaw, di->dev_id, cluster_num, buf, &zero_bytes);
- qemu_rec_mutex_unlock(&backup_state.backup_mutex);
+ qemu_mutex_unlock(&backup_state.backup_mutex);
++cluster_num;
if (buf) {
@@ -207,11 +207,11 @@ static void coroutine_fn pvebackup_co_cleanup(void *unused)
{
assert(qemu_in_coroutine());
- qemu_rec_mutex_lock(&backup_state.backup_mutex);
+ qemu_mutex_lock(&backup_state.backup_mutex);
- qemu_rec_mutex_lock(&backup_state.stat.lock);
+ qemu_mutex_lock(&backup_state.stat.lock);
backup_state.stat.end_time = time(NULL);
- qemu_rec_mutex_unlock(&backup_state.stat.lock);
+ qemu_mutex_unlock(&backup_state.stat.lock);
if (backup_state.vmaw) {
Error *local_err = NULL;
@@ -239,7 +239,7 @@ static void coroutine_fn pvebackup_co_cleanup(void *unused)
g_list_free(backup_state.di_list);
backup_state.di_list = NULL;
- qemu_rec_mutex_unlock(&backup_state.backup_mutex);
+ qemu_mutex_unlock(&backup_state.backup_mutex);
}
static void coroutine_fn pvebackup_complete_stream(void *opaque)
@@ -267,7 +267,7 @@ static void pvebackup_complete_cb(void *opaque, int ret)
PVEBackupDevInfo *di = opaque;
- qemu_rec_mutex_lock(&backup_state.backup_mutex);
+ qemu_mutex_lock(&backup_state.backup_mutex);
di->completed = true;
@@ -288,7 +288,7 @@ static void pvebackup_complete_cb(void *opaque, int ret)
g_free(di);
- qemu_rec_mutex_unlock(&backup_state.backup_mutex);
+ qemu_mutex_unlock(&backup_state.backup_mutex);
pvebackup_run_next_job();
}
@@ -299,7 +299,7 @@ static void pvebackup_cancel(void)
error_setg(&cancel_err, "backup canceled");
pvebackup_propagate_error(cancel_err);
- qemu_rec_mutex_lock(&backup_state.backup_mutex);
+ qemu_mutex_lock(&backup_state.backup_mutex);
if (backup_state.vmaw) {
/* make sure vma writer does not block anymore */
@@ -310,13 +310,13 @@ static void pvebackup_cancel(void)
proxmox_backup_abort(backup_state.pbs, "backup canceled");
}
- qemu_rec_mutex_unlock(&backup_state.backup_mutex);
+ qemu_mutex_unlock(&backup_state.backup_mutex);
for(;;) {
BlockJob *next_job = NULL;
- qemu_rec_mutex_lock(&backup_state.backup_mutex);
+ qemu_mutex_lock(&backup_state.backup_mutex);
GList *l = backup_state.di_list;
while (l) {
@@ -330,7 +330,7 @@ static void pvebackup_cancel(void)
}
}
- qemu_rec_mutex_unlock(&backup_state.backup_mutex);
+ qemu_mutex_unlock(&backup_state.backup_mutex);
if (next_job) {
AioContext *aio_context = next_job->job.aio_context;
@@ -403,7 +403,7 @@ static void pvebackup_run_next_job(void)
{
assert(!qemu_in_coroutine());
- qemu_rec_mutex_lock(&backup_state.backup_mutex);
+ qemu_mutex_lock(&backup_state.backup_mutex);
GList *l = backup_state.di_list;
while (l) {
@@ -413,7 +413,7 @@ static void pvebackup_run_next_job(void)
BlockJob *job = lookup_active_block_job(di);
if (job) {
- qemu_rec_mutex_unlock(&backup_state.backup_mutex);
+ qemu_mutex_unlock(&backup_state.backup_mutex);
AioContext *aio_context = job->job.aio_context;
aio_context_acquire(aio_context);
@@ -431,7 +431,7 @@ static void pvebackup_run_next_job(void)
}
}
- qemu_rec_mutex_unlock(&backup_state.backup_mutex);
+ qemu_mutex_unlock(&backup_state.backup_mutex);
block_on_coroutine_fn(pvebackup_co_cleanup, NULL); // no more jobs, run cleanup
}
@@ -543,10 +543,10 @@ static void coroutine_fn pvebackup_co_prepare(void *opaque)
const char *config_name = "qemu-server.conf";
const char *firewall_name = "qemu-server.fw";
- qemu_rec_mutex_lock(&backup_state.backup_mutex);
+ qemu_mutex_lock(&backup_state.backup_mutex);
if (backup_state.di_list) {
- qemu_rec_mutex_unlock(&backup_state.backup_mutex);
+ qemu_mutex_unlock(&backup_state.backup_mutex);
error_set(task->errp, ERROR_CLASS_GENERIC_ERROR,
"previous backup not finished");
return;
@@ -689,6 +689,8 @@ static void coroutine_fn pvebackup_co_prepare(void *opaque)
goto err;
}
+ vma_writer_set_external_lock(vmaw, &backup_state.backup_mutex);
+
/* register all devices for vma writer */
l = di_list;
while (l) {
@@ -760,7 +762,7 @@ static void coroutine_fn pvebackup_co_prepare(void *opaque)
}
/* initialize global backup_state now */
- qemu_rec_mutex_lock(&backup_state.stat.lock);
+ qemu_mutex_lock(&backup_state.stat.lock);
if (backup_state.stat.error) {
error_free(backup_state.stat.error);
@@ -783,7 +785,7 @@ static void coroutine_fn pvebackup_co_prepare(void *opaque)
backup_state.stat.transferred = 0;
backup_state.stat.zero_bytes = 0;
- qemu_rec_mutex_unlock(&backup_state.stat.lock);
+ qemu_mutex_unlock(&backup_state.stat.lock);
backup_state.speed = (task->has_speed && task->speed > 0) ? task->speed : 0;
@@ -792,7 +794,7 @@ static void coroutine_fn pvebackup_co_prepare(void *opaque)
backup_state.di_list = di_list;
- qemu_rec_mutex_unlock(&backup_state.backup_mutex);
+ qemu_mutex_unlock(&backup_state.backup_mutex);
uuid_info = g_malloc0(sizeof(*uuid_info));
uuid_info->UUID = uuid_str;
@@ -836,7 +838,7 @@ err:
rmdir(backup_dir);
}
- qemu_rec_mutex_unlock(&backup_state.backup_mutex);
+ qemu_mutex_unlock(&backup_state.backup_mutex);
task->result = NULL;
return;
@@ -884,9 +886,9 @@ UuidInfo *qmp_backup(
block_on_coroutine_fn(pvebackup_co_prepare, &task);
if (*errp == NULL) {
- qemu_rec_mutex_lock(&backup_state.backup_mutex);
+ qemu_mutex_lock(&backup_state.backup_mutex);
create_backup_jobs();
- qemu_rec_mutex_unlock(&backup_state.backup_mutex);
+ qemu_mutex_unlock(&backup_state.backup_mutex);
pvebackup_run_next_job();
}
@@ -897,11 +899,11 @@ BackupStatus *qmp_query_backup(Error **errp)
{
BackupStatus *info = g_malloc0(sizeof(*info));
- qemu_rec_mutex_lock(&backup_state.stat.lock);
+ qemu_mutex_lock(&backup_state.stat.lock);
if (!backup_state.stat.start_time) {
/* not started, return {} */
- qemu_rec_mutex_unlock(&backup_state.stat.lock);
+ qemu_mutex_unlock(&backup_state.stat.lock);
return info;
}
@@ -938,7 +940,7 @@ BackupStatus *qmp_query_backup(Error **errp)
info->has_transferred = true;
info->transferred = backup_state.stat.transferred;
- qemu_rec_mutex_unlock(&backup_state.stat.lock);
+ qemu_mutex_unlock(&backup_state.stat.lock);
return info;
}
diff --git a/vma-writer.c b/vma-writer.c
index fe86b18a60..f3fa8e3b4c 100644
--- a/vma-writer.c
+++ b/vma-writer.c
@@ -68,8 +68,14 @@ struct VmaWriter {
uint32_t config_names[VMA_MAX_CONFIGS]; /* offset into blob_buffer table */
uint32_t config_data[VMA_MAX_CONFIGS]; /* offset into blob_buffer table */
uint32_t config_count;
+
+ QemuMutex *external_lock;
};
+void vma_writer_set_external_lock(VmaWriter *vmaw, QemuMutex *lock) {
+ vmaw->external_lock = lock;
+}
+
void vma_writer_set_error(VmaWriter *vmaw, const char *fmt, ...)
{
va_list ap;
@@ -199,13 +205,20 @@ int vma_writer_register_stream(VmaWriter *vmaw, const char *devname,
return n;
}
-static void coroutine_fn yield_until_fd_writable(int fd)
+static void coroutine_fn yield_until_fd_writable(int fd, QemuMutex *external_lock)
{
assert(qemu_in_coroutine());
AioContext *ctx = qemu_get_current_aio_context();
aio_set_fd_handler(ctx, fd, false, NULL, (IOHandler *)qemu_coroutine_enter,
NULL, qemu_coroutine_self());
+ if (external_lock) {
+ /* still protected from re-entering via flush_lock */
+ qemu_mutex_unlock(external_lock);
+ }
qemu_coroutine_yield();
+ if (!external_lock) {
+ qemu_mutex_lock(external_lock);
+ }
aio_set_fd_handler(ctx, fd, false, NULL, NULL, NULL, NULL);
}
@@ -227,11 +240,16 @@ vma_queue_write(VmaWriter *vmaw, const void *buf, size_t bytes)
while (done < bytes) {
if (vmaw->status < 0) {
- DPRINTF("vma_queue_write detected canceled backup\n");
+ DPRINTF("vma_queue_write detected cancelled backup\n");
+ done = -1;
+ break;
+ }
+ yield_until_fd_writable(vmaw->fd, vmaw->external_lock);
+ if (vmaw->closed || vmaw->status < 0) {
+ DPRINTF("vma_queue_write backup cancelled after waiting for fd\n");
done = -1;
break;
}
- yield_until_fd_writable(vmaw->fd);
ret = write(vmaw->fd, buf + done, bytes - done);
if (ret > 0) {
done += ret;
@@ -501,7 +519,7 @@ vma_writer_flush_output(VmaWriter *vmaw)
int ret = vma_writer_flush(vmaw);
qemu_co_mutex_unlock(&vmaw->flush_lock);
if (ret < 0) {
- vma_writer_set_error(vmaw, "vma_writer_flush_header failed");
+ vma_writer_set_error(vmaw, "vma_writer_flush_output failed");
}
return ret;
}
@@ -570,7 +588,7 @@ static int vma_writer_get_buffer(VmaWriter *vmaw)
while (vmaw->outbuf_count >= (VMA_BLOCKS_PER_EXTENT - 1)) {
ret = vma_writer_flush(vmaw);
if (ret < 0) {
- vma_writer_set_error(vmaw, "vma_writer_get_buffer: flush failed");
+ vma_writer_set_error(vmaw, "vma_writer_get_header: flush failed");
break;
}
}
diff --git a/vma.h b/vma.h
index c895c97f6d..ec6f09e83e 100644
--- a/vma.h
+++ b/vma.h
@@ -115,6 +115,7 @@ typedef struct VmaDeviceInfo {
} VmaDeviceInfo;
VmaWriter *vma_writer_create(const char *filename, uuid_t uuid, Error **errp);
+void vma_writer_set_external_lock(VmaWriter *vmaw, QemuMutex *lock);
int vma_writer_close(VmaWriter *vmaw, Error **errp);
void vma_writer_error_propagate(VmaWriter *vmaw, Error **errp);
void vma_writer_destroy(VmaWriter *vmaw);
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