src/util/virfile.c | 7 +++++++ 1 file changed, 7 insertions(+)
>From d9f7ed2af581222804392f9b93dc6aaf7d8c8995 Mon Sep 17 00:00:00 2001
From: Bihong Yu <yubihong@huawei.com>
Date: Tue, 16 Jun 2020 22:08:55 +0800
Subject: [PATCH] utils: add mutex to avoid races in virfile
There are races condiction to make '/run/libvirt/qemu/dbus' directory in
virDirCreateNoFork() while concurrent start VMs, and get "failed to create
directory '/run/libvirt/qemu/dbus': File exists" error message. Add an
mutex to avoid races.
Signed-off-by:Bihong Yu <yubihong@huawei.com>
Reviewed-by:Chuan Zheng <zhengchuan@huawei.com>
Reviewed-by:alexchen <alex.chen@huawei.com>
---
src/util/virfile.c | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/src/util/virfile.c b/src/util/virfile.c
index 20260a2..ae02a6e 100644
--- a/src/util/virfile.c
+++ b/src/util/virfile.c
@@ -88,6 +88,7 @@
#include "virstring.h"
#include "virutil.h"
#include "virsocket.h"
+#include "virthread.h"
#define VIR_FROM_THIS VIR_FROM_NONE
@@ -108,6 +109,9 @@ VIR_LOG_INIT("util.file");
# define O_DIRECT 0
#endif
+/* Global mutex to avoid races */
+virMutex fileLock = VIR_MUTEX_INITIALIZER;
+
int virFileClose(int *fdptr, virFileCloseFlags flags)
{
int saved_errno = 0;
@@ -2612,15 +2616,18 @@ virDirCreateNoFork(const char *path,
struct stat st;
bool created = false;
+ virMutexLock(&fileLock);
if (!((flags & VIR_DIR_CREATE_ALLOW_EXIST) && virFileExists(path))) {
if (mkdir(path, mode) < 0) {
ret = -errno;
virReportSystemError(errno, _("failed to create directory '%s'"),
path);
+ virMutexUnlock(&fileLock);
goto error;
}
created = true;
}
+ virMutexUnlock(&fileLock);
if (stat(path, &st) == -1) {
ret = -errno;
--
1.8.3.1
From d9f7ed2af581222804392f9b93dc6aaf7d8c8995 Mon Sep 17 00:00:00 2001
From: Bihong Yu <yubihong@huawei.com>
Date: Tue, 16 Jun 2020 22:08:55 +0800
Subject: [PATCH] utils: add mutex to avoid races in virfile
There are races condiction to make '/run/libvirt/qemu/dbus' directory in
virDirCreateNoFork() while concurrent start VMs, and get "failed to create
directory '/run/libvirt/qemu/dbus': File exists" error message. Add an
mutex to avoid races.
Signed-off-by:Bihong Yu <yubihong@huawei.com>
Reviewed-by:Chuan Zheng <zhengchuan@huawei.com>
Reviewed-by:alexchen <alex.chen@huawei.com>
---
src/util/virfile.c | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/src/util/virfile.c b/src/util/virfile.c
index 20260a2..ae02a6e 100644
--- a/src/util/virfile.c
+++ b/src/util/virfile.c
@@ -88,6 +88,7 @@
#include "virstring.h"
#include "virutil.h"
#include "virsocket.h"
+#include "virthread.h"
#define VIR_FROM_THIS VIR_FROM_NONE
@@ -108,6 +109,9 @@ VIR_LOG_INIT("util.file");
# define O_DIRECT 0
#endif
+/* Global mutex to avoid races */
+virMutex fileLock = VIR_MUTEX_INITIALIZER;
+
int virFileClose(int *fdptr, virFileCloseFlags flags)
{
int saved_errno = 0;
@@ -2612,15 +2616,18 @@ virDirCreateNoFork(const char *path,
struct stat st;
bool created = false;
+ virMutexLock(&fileLock);
if (!((flags & VIR_DIR_CREATE_ALLOW_EXIST) && virFileExists(path))) {
if (mkdir(path, mode) < 0) {
ret = -errno;
virReportSystemError(errno, _("failed to create directory '%s'"),
path);
+ virMutexUnlock(&fileLock);
goto error;
}
created = true;
}
+ virMutexUnlock(&fileLock);
if (stat(path, &st) == -1) {
ret = -errno;
--
1.8.3.1
On Tue, Jun 16, 2020 at 10:39:46PM +0800, Bihong Yu wrote:
> >From d9f7ed2af581222804392f9b93dc6aaf7d8c8995 Mon Sep 17 00:00:00 2001
> From: Bihong Yu <yubihong@huawei.com>
> Date: Tue, 16 Jun 2020 22:08:55 +0800
> Subject: [PATCH] utils: add mutex to avoid races in virfile
>
> There are races condiction to make '/run/libvirt/qemu/dbus' directory in
> virDirCreateNoFork() while concurrent start VMs, and get "failed to create
> directory '/run/libvirt/qemu/dbus': File exists" error message. Add an
> mutex to avoid races.
>
> Signed-off-by:Bihong Yu <yubihong@huawei.com>
> Reviewed-by:Chuan Zheng <zhengchuan@huawei.com>
> Reviewed-by:alexchen <alex.chen@huawei.com>
> ---
> src/util/virfile.c | 7 +++++++
> 1 file changed, 7 insertions(+)
>
> diff --git a/src/util/virfile.c b/src/util/virfile.c
> index 20260a2..ae02a6e 100644
> --- a/src/util/virfile.c
> +++ b/src/util/virfile.c
> @@ -88,6 +88,7 @@
> #include "virstring.h"
> #include "virutil.h"
> #include "virsocket.h"
> +#include "virthread.h"
>
> #define VIR_FROM_THIS VIR_FROM_NONE
>
> @@ -108,6 +109,9 @@ VIR_LOG_INIT("util.file");
> # define O_DIRECT 0
> #endif
>
> +/* Global mutex to avoid races */
> +virMutex fileLock = VIR_MUTEX_INITIALIZER;
> +
> int virFileClose(int *fdptr, virFileCloseFlags flags)
> {
> int saved_errno = 0;
> @@ -2612,15 +2616,18 @@ virDirCreateNoFork(const char *path,
> struct stat st;
> bool created = false;
>
> + virMutexLock(&fileLock);
> if (!((flags & VIR_DIR_CREATE_ALLOW_EXIST) && virFileExists(path))) {
> if (mkdir(path, mode) < 0) {
Instead of adding a mutex we should get rid of the virFileExists check
entirely. Instead check "errno == EEXIST && (flags & VIR_DIR_CREATE_ALLOW_EXIST)"
before reporting an error.
> ret = -errno;
> virReportSystemError(errno, _("failed to create directory '%s'"),
> path);
> + virMutexUnlock(&fileLock);
> goto error;
> }
> created = true;
> }
> + virMutexUnlock(&fileLock);
>
> if (stat(path, &st) == -1) {
> ret = -errno;
Regards,
Daniel
--
|: https://berrange.com -o- https://www.flickr.com/photos/dberrange :|
|: https://libvirt.org -o- https://fstop138.berrange.com :|
|: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|
Yes, it a good idea. I will fix it.
On 2020/6/16 23:16, Daniel P. Berrangé wrote:
> On Tue, Jun 16, 2020 at 10:39:46PM +0800, Bihong Yu wrote:
>> >From d9f7ed2af581222804392f9b93dc6aaf7d8c8995 Mon Sep 17 00:00:00 2001
>> From: Bihong Yu <yubihong@huawei.com>
>> Date: Tue, 16 Jun 2020 22:08:55 +0800
>> Subject: [PATCH] utils: add mutex to avoid races in virfile
>>
>> There are races condiction to make '/run/libvirt/qemu/dbus' directory in
>> virDirCreateNoFork() while concurrent start VMs, and get "failed to create
>> directory '/run/libvirt/qemu/dbus': File exists" error message. Add an
>> mutex to avoid races.
>>
>> Signed-off-by:Bihong Yu <yubihong@huawei.com>
>> Reviewed-by:Chuan Zheng <zhengchuan@huawei.com>
>> Reviewed-by:alexchen <alex.chen@huawei.com>
>> ---
>> src/util/virfile.c | 7 +++++++
>> 1 file changed, 7 insertions(+)
>>
>> diff --git a/src/util/virfile.c b/src/util/virfile.c
>> index 20260a2..ae02a6e 100644
>> --- a/src/util/virfile.c
>> +++ b/src/util/virfile.c
>> @@ -88,6 +88,7 @@
>> #include "virstring.h"
>> #include "virutil.h"
>> #include "virsocket.h"
>> +#include "virthread.h"
>>
>> #define VIR_FROM_THIS VIR_FROM_NONE
>>
>> @@ -108,6 +109,9 @@ VIR_LOG_INIT("util.file");
>> # define O_DIRECT 0
>> #endif
>>
>> +/* Global mutex to avoid races */
>> +virMutex fileLock = VIR_MUTEX_INITIALIZER;
>> +
>> int virFileClose(int *fdptr, virFileCloseFlags flags)
>> {
>> int saved_errno = 0;
>> @@ -2612,15 +2616,18 @@ virDirCreateNoFork(const char *path,
>> struct stat st;
>> bool created = false;
>>
>> + virMutexLock(&fileLock);
>> if (!((flags & VIR_DIR_CREATE_ALLOW_EXIST) && virFileExists(path))) {
>> if (mkdir(path, mode) < 0) {
>
> Instead of adding a mutex we should get rid of the virFileExists check
> entirely. Instead check "errno == EEXIST && (flags & VIR_DIR_CREATE_ALLOW_EXIST)"
> before reporting an error.
>
>> ret = -errno;
>> virReportSystemError(errno, _("failed to create directory '%s'"),
>> path);
>> + virMutexUnlock(&fileLock);
>> goto error;
>> }
>> created = true;
>> }
>> + virMutexUnlock(&fileLock);
>>
>> if (stat(path, &st) == -1) {
>> ret = -errno;
>
> Regards,
> Daniel
>
© 2016 - 2024 Red Hat, Inc.