[PATCH] mtools: fix race issue while mtools invoked frequently

[PATCH] mtools: fix race issue while mtools invoked frequently

[Hongxu Jia]

While invoking mtools frequently, the unblocking request
caused race issue. Here is an example of syslinux
[snip]
dd if=/dev/zero of=floppy.img bs=1024 count=144
losetup /dev/loop1 floppy.img
mkdosfs /dev/loop1
syslinux -i /dev/loop1
|plain floppy: device "/proc/6351/fd/3" busy (Resource temporarily unavailable):
|Cannot initialize 'S:'
|Bad target s:/ldlinux.sys
[snip]

The idea is from:
https://bugzilla.redhat.com/show_bug.cgi?id=1235016
https://groups.google.com/a/chromium.org/forum/#!msg/chromium-os-dev/bRPUCFHoBTQ/ZjB8kjjx1vUJ

Signed-off-by: Hongxu Jia <hongxu.jia@windriver.com>
---
 ...01-remove-LOCK_NB-to-use-blocking-request.patch | 44 ++++++++++++++++++++++
 meta/recipes-devtools/mtools/mtools_4.0.18.bb      |  1 +
 2 files changed, 45 insertions(+)
 create mode 100644 meta/recipes-devtools/mtools/mtools/0001-remove-LOCK_NB-to-use-blocking-request.patch

diff --git a/meta/recipes-devtools/mtools/mtools/0001-remove-LOCK_NB-to-use-blocking-request.patch b/meta/recipes-devtools/mtools/mtools/0001-remove-LOCK_NB-to-use-blocking-request.patch
new file mode 100644
index 0000000..47385a5
--- /dev/null
+++ b/meta/recipes-devtools/mtools/mtools/0001-remove-LOCK_NB-to-use-blocking-request.patch
@@ -0,0 +1,44 @@
+From 5bdbfe0a63fed48104b17412854b26ee2275869a Mon Sep 17 00:00:00 2001
+From: Hongxu Jia <hongxu.jia@windriver.com>
+Date: Wed, 22 Aug 2018 16:54:39 +0800
+Subject: [PATCH] remove LOCK_NB to use blocking request
+
+While invoking mtools frequently, the unblocking request
+caused race issue. Here is an example of syslinux
+[snip]
+dd if=/dev/zero of=floppy.img bs=1024 count=144
+losetup /dev/loop1 floppy.img
+mkdosfs /dev/loop1
+syslinux -i /dev/loop1
+|plain floppy: device "/proc/6351/fd/3" busy (Resource temporarily unavailable):
+|Cannot initialize 'S:'
+|Bad target s:/ldlinux.sys
+[snip]
+
+The idea is from:
+https://bugzilla.redhat.com/show_bug.cgi?id=1235016
+https://groups.google.com/a/chromium.org/forum/#!msg/chromium-os-dev/bRPUCFHoBTQ/ZjB8kjjx1vUJ
+
+Upstream-Status: Pending
+
+Signed-off-by: Hongxu Jia <hongxu.jia@windriver.com>
+---
+ lockdev.h | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/lockdev.h b/lockdev.h
+index 4467bc2..5a135ad 100644
+--- a/lockdev.h
++++ b/lockdev.h
+@@ -43,7 +43,7 @@ int lock_dev(int fd, int mode, struct device *dev)
+ 		return 0;
+ 
+ #if (defined(HAVE_FLOCK) && defined (LOCK_EX) && defined(LOCK_NB))
+-	if (flock(fd, (mode ? LOCK_EX : LOCK_SH)|LOCK_NB) < 0)
++	if (flock(fd, (mode ? LOCK_EX : LOCK_SH)) < 0)
+ #else /* FLOCK */
+ 
+ #if (defined(HAVE_LOCKF) && defined(F_TLOCK))
+-- 
+2.7.4
+
diff --git a/meta/recipes-devtools/mtools/mtools_4.0.18.bb b/meta/recipes-devtools/mtools/mtools_4.0.18.bb
index dcd32ed..91f7b7c 100644
--- a/meta/recipes-devtools/mtools/mtools_4.0.18.bb
+++ b/meta/recipes-devtools/mtools/mtools_4.0.18.bb
@@ -31,6 +31,7 @@ SRC_URI = "${GNU_MIRROR}/mtools/mtools-${PV}.tar.bz2 \
            file://mtools-makeinfo.patch \
            file://no-x11.gplv3.patch \
            file://0001-Continue-even-if-fs-size-is-not-divisible-by-sectors.patch \
+           file://0001-remove-LOCK_NB-to-use-blocking-request.patch \
            "
 
 SRC_URI_append_class-native = " file://disable-hardcoded-configs.patch"
-- 
2.7.4

Re: [PATCH] mtools: fix race issue while mtools invoked frequently

[Randy MacLeod]

On 08/22/2018 05:16 AM, Hongxu Jia wrote:
> While invoking mtools frequently, the unblocking request

s/unblocking/non-blocking/

I would read 'unblocking' as a request that results in the
system becoming unblocked whereas non-blocking is more
commonly used and refers to function calls that will
not result in calling blocking system calls.

Indeed the NB in LOCK_NB stand for non-blocking.

> caused race issue. Here is an example of syslinux
> [snip]
> dd if=/dev/zero of=floppy.img bs=1024 count=144
> losetup /dev/loop1 floppy.img
> mkdosfs /dev/loop1
> syslinux -i /dev/loop1
> |plain floppy: device "/proc/6351/fd/3" busy (Resource temporarily unavailable):
> |Cannot initialize 'S:'
> |Bad target s:/ldlinux.sys
> [snip]
> 
> The idea is from:
> https://bugzilla.redhat.com/show_bug.cgi?id=1235016
> https://groups.google.com/a/chromium.org/forum/#!msg/chromium-os-dev/bRPUCFHoBTQ/ZjB8kjjx1vUJ

I read though most of that and it seems that people think
that this may be a work-around. What do you think?

If I were used to using mtools and it never blocked,
the I'd certainly be upset that we patched it to block.
lockdev.h gets used by:

$ grep -r "lockdev.h" mtools-4.0.18/
mtools-4.0.18/plain_io.c:#include "lockdev.h"
mtools-4.0.18/floppyd.c:#include "lockdev.h"

so until you can explain what the root cause of the
problem is more clearly, and why this change won't cause
problems for users of mtools, I think you should continue
to work on this problem.

Or maybe the commit just needs a more details technical
explanation that summarizes the long thread that you linked
to...

../Randy


> 
> Signed-off-by: Hongxu Jia <hongxu.jia@windriver.com>
> ---
>   ...01-remove-LOCK_NB-to-use-blocking-request.patch | 44 ++++++++++++++++++++++
>   meta/recipes-devtools/mtools/mtools_4.0.18.bb      |  1 +
>   2 files changed, 45 insertions(+)
>   create mode 100644 meta/recipes-devtools/mtools/mtools/0001-remove-LOCK_NB-to-use-blocking-request.patch
> 
> diff --git a/meta/recipes-devtools/mtools/mtools/0001-remove-LOCK_NB-to-use-blocking-request.patch b/meta/recipes-devtools/mtools/mtools/0001-remove-LOCK_NB-to-use-blocking-request.patch
> new file mode 100644
> index 0000000..47385a5
> --- /dev/null
> +++ b/meta/recipes-devtools/mtools/mtools/0001-remove-LOCK_NB-to-use-blocking-request.patch
> @@ -0,0 +1,44 @@
> +From 5bdbfe0a63fed48104b17412854b26ee2275869a Mon Sep 17 00:00:00 2001
> +From: Hongxu Jia <hongxu.jia@windriver.com>
> +Date: Wed, 22 Aug 2018 16:54:39 +0800
> +Subject: [PATCH] remove LOCK_NB to use blocking request
> +
> +While invoking mtools frequently, the unblocking request
> +caused race issue. Here is an example of syslinux
> +[snip]
> +dd if=/dev/zero of=floppy.img bs=1024 count=144
> +losetup /dev/loop1 floppy.img
> +mkdosfs /dev/loop1
> +syslinux -i /dev/loop1
> +|plain floppy: device "/proc/6351/fd/3" busy (Resource temporarily unavailable):
> +|Cannot initialize 'S:'
> +|Bad target s:/ldlinux.sys
> +[snip]
> +
> +The idea is from:
> +https://bugzilla.redhat.com/show_bug.cgi?id=1235016
> +https://groups.google.com/a/chromium.org/forum/#!msg/chromium-os-dev/bRPUCFHoBTQ/ZjB8kjjx1vUJ
> +
> +Upstream-Status: Pending
> +
> +Signed-off-by: Hongxu Jia <hongxu.jia@windriver.com>
> +---
> + lockdev.h | 2 +-
> + 1 file changed, 1 insertion(+), 1 deletion(-)
> +
> +diff --git a/lockdev.h b/lockdev.h
> +index 4467bc2..5a135ad 100644
> +--- a/lockdev.h
> ++++ b/lockdev.h
> +@@ -43,7 +43,7 @@ int lock_dev(int fd, int mode, struct device *dev)
> + 		return 0;
> +
> + #if (defined(HAVE_FLOCK) && defined (LOCK_EX) && defined(LOCK_NB))
> +-	if (flock(fd, (mode ? LOCK_EX : LOCK_SH)|LOCK_NB) < 0)
> ++	if (flock(fd, (mode ? LOCK_EX : LOCK_SH)) < 0)

> + #else /* FLOCK */
> +
> + #if (defined(HAVE_LOCKF) && defined(F_TLOCK))
> +--
> +2.7.4
> +
> diff --git a/meta/recipes-devtools/mtools/mtools_4.0.18.bb b/meta/recipes-devtools/mtools/mtools_4.0.18.bb
> index dcd32ed..91f7b7c 100644
> --- a/meta/recipes-devtools/mtools/mtools_4.0.18.bb
> +++ b/meta/recipes-devtools/mtools/mtools_4.0.18.bb
> @@ -31,6 +31,7 @@ SRC_URI = "${GNU_MIRROR}/mtools/mtools-${PV}.tar.bz2 \
>              file://mtools-makeinfo.patch \
>              file://no-x11.gplv3.patch \
>              file://0001-Continue-even-if-fs-size-is-not-divisible-by-sectors.patch \
> +           file://0001-remove-LOCK_NB-to-use-blocking-request.patch \
>              "
>   
>   SRC_URI_append_class-native = " file://disable-hardcoded-configs.patch"
> 


-- 
# Randy MacLeod
# Wind River Linux

Re: [PATCH] mtools: fix race issue while mtools invoked frequently

[Hongxu Jia]

On 2018年08月24日 04:47, Randy MacLeod wrote:
> On 08/22/2018 05:16 AM, Hongxu Jia wrote:
>> While invoking mtools frequently, the unblocking request
>
> s/unblocking/non-blocking/
>
> I would read 'unblocking' as a request that results in the
> system becoming unblocked whereas non-blocking is more
> commonly used and refers to function calls that will
> not result in calling blocking system calls.
>

OK, thanks  to point it out

> Indeed the NB in LOCK_NB stand for non-blocking.
>
>> caused race issue. Here is an example of syslinux
>> [snip]
>> dd if=/dev/zero of=floppy.img bs=1024 count=144
>> losetup /dev/loop1 floppy.img
>> mkdosfs /dev/loop1
>> syslinux -i /dev/loop1
>> |plain floppy: device "/proc/6351/fd/3" busy (Resource temporarily 
>> unavailable):
>> |Cannot initialize 'S:'
>> |Bad target s:/ldlinux.sys
>> [snip]
>>
>> The idea is from:
>> https://bugzilla.redhat.com/show_bug.cgi?id=1235016
>> https://groups.google.com/a/chromium.org/forum/#!msg/chromium-os-dev/bRPUCFHoBTQ/ZjB8kjjx1vUJ 
>>
>
> I read though most of that and it seems that people think
> that this may be a work-around. What do you think?
>
> If I were used to using mtools and it never blocked,
> the I'd certainly be upset that we patched it to block.
> lockdev.h gets used by:
>
> $ grep -r "lockdev.h" mtools-4.0.18/
> mtools-4.0.18/plain_io.c:#include "lockdev.h"
> mtools-4.0.18/floppyd.c:#include "lockdev.h"
>
> so until you can explain what the root cause of the
> problem is more clearly, and why this change won't cause
> problems for users of mtools, I think you should continue
> to work on this problem.
>
> Or maybe the commit just needs a more details technical
> explanation that summarizes the long thread that you linked
> to...
>

 From the thread, and my confirm, the last update of mtools is 2013-01-09,
and Ubuntu 1604/1804 has the same issue on `syslinux -i /dev/loop1'.

With some digging on mtools, the user of mtools usually have a mtools.conf
to customize it, and use `nolock' for specific device to workaround
flock invoking (such as `drive c: file="/dev/sda1" nolock=1'). but 
unfortunately
syslinux does not follow the rule (it is hardly to know `/proc/***/fd/3' 
before
invoking syslinux )

[snip]
  42         if(IS_NOLOCK(dev))
  43                 return 0;
  44
  45 #if (defined(HAVE_FLOCK) && defined (LOCK_EX) && defined(LOCK_NB))
  46         if (flock(fd, (mode ? LOCK_EX : LOCK_SH)) < 0)
[snip]

On the other side, the error of `plain floppy: device "***" busy' 
exactly comes
from the error of flock invoking (not actual resource busy), so the fix 
is safe
for re-entry of mtools
[snip]
         /* lock the device on writes */
         if (locked && lock_dev(This->fd, mode == O_RDWR, dev)) {
                 if(errmsg)
#ifdef HAVE_SNPRINTF
                         snprintf(errmsg,199,
                                 "plain floppy: device \"%s\" busy (%s):",
                                 dev ? dev->name : "unknown", 
strerror(errno));
[snip]

I think long time no maintenance of mtools, and not to fix this 
obviously issue.

//Hongxu

> ../Randy
>
>
>>
>> Signed-off-by: Hongxu Jia <hongxu.jia@windriver.com>
>> ---
>>   ...01-remove-LOCK_NB-to-use-blocking-request.patch | 44 
>> ++++++++++++++++++++++
>>   meta/recipes-devtools/mtools/mtools_4.0.18.bb      |  1 +
>>   2 files changed, 45 insertions(+)
>>   create mode 100644 
>> meta/recipes-devtools/mtools/mtools/0001-remove-LOCK_NB-to-use-blocking-request.patch
>>
>> diff --git 
>> a/meta/recipes-devtools/mtools/mtools/0001-remove-LOCK_NB-to-use-blocking-request.patch 
>> b/meta/recipes-devtools/mtools/mtools/0001-remove-LOCK_NB-to-use-blocking-request.patch 
>>
>> new file mode 100644
>> index 0000000..47385a5
>> --- /dev/null
>> +++ 
>> b/meta/recipes-devtools/mtools/mtools/0001-remove-LOCK_NB-to-use-blocking-request.patch
>> @@ -0,0 +1,44 @@
>> +From 5bdbfe0a63fed48104b17412854b26ee2275869a Mon Sep 17 00:00:00 2001
>> +From: Hongxu Jia <hongxu.jia@windriver.com>
>> +Date: Wed, 22 Aug 2018 16:54:39 +0800
>> +Subject: [PATCH] remove LOCK_NB to use blocking request
>> +
>> +While invoking mtools frequently, the unblocking request
>> +caused race issue. Here is an example of syslinux
>> +[snip]
>> +dd if=/dev/zero of=floppy.img bs=1024 count=144
>> +losetup /dev/loop1 floppy.img
>> +mkdosfs /dev/loop1
>> +syslinux -i /dev/loop1
>> +|plain floppy: device "/proc/6351/fd/3" busy (Resource temporarily 
>> unavailable):
>> +|Cannot initialize 'S:'
>> +|Bad target s:/ldlinux.sys
>> +[snip]
>> +
>> +The idea is from:
>> +https://bugzilla.redhat.com/show_bug.cgi?id=1235016
>> +https://groups.google.com/a/chromium.org/forum/#!msg/chromium-os-dev/bRPUCFHoBTQ/ZjB8kjjx1vUJ 
>>
>> +
>> +Upstream-Status: Pending
>> +
>> +Signed-off-by: Hongxu Jia <hongxu.jia@windriver.com>
>> +---
>> + lockdev.h | 2 +-
>> + 1 file changed, 1 insertion(+), 1 deletion(-)
>> +
>> +diff --git a/lockdev.h b/lockdev.h
>> +index 4467bc2..5a135ad 100644
>> +--- a/lockdev.h
>> ++++ b/lockdev.h
>> +@@ -43,7 +43,7 @@ int lock_dev(int fd, int mode, struct device *dev)
>> +         return 0;
>> +
>> + #if (defined(HAVE_FLOCK) && defined (LOCK_EX) && defined(LOCK_NB))
>> +-    if (flock(fd, (mode ? LOCK_EX : LOCK_SH)|LOCK_NB) < 0)
>> ++    if (flock(fd, (mode ? LOCK_EX : LOCK_SH)) < 0)
>
>> + #else /* FLOCK */
>> +
>> + #if (defined(HAVE_LOCKF) && defined(F_TLOCK))
>> +--
>> +2.7.4
>> +
>> diff --git a/meta/recipes-devtools/mtools/mtools_4.0.18.bb 
>> b/meta/recipes-devtools/mtools/mtools_4.0.18.bb
>> index dcd32ed..91f7b7c 100644
>> --- a/meta/recipes-devtools/mtools/mtools_4.0.18.bb
>> +++ b/meta/recipes-devtools/mtools/mtools_4.0.18.bb
>> @@ -31,6 +31,7 @@ SRC_URI = "${GNU_MIRROR}/mtools/mtools-${PV}.tar.bz2 \
>>              file://mtools-makeinfo.patch \
>>              file://no-x11.gplv3.patch \
>> file://0001-Continue-even-if-fs-size-is-not-divisible-by-sectors.patch \
>> + file://0001-remove-LOCK_NB-to-use-blocking-request.patch \
>>              "
>>     SRC_URI_append_class-native = " 
>> file://disable-hardcoded-configs.patch"
>>
>
>

Re: [PATCH] mtools: fix race issue while mtools invoked frequently

[Randy MacLeod]

On 08/23/2018 11:06 PM, Hongxu Jia wrote:
> On 2018年08月24日 04:47, Randy MacLeod wrote:
>> On 08/22/2018 05:16 AM, Hongxu Jia wrote:
>>> While invoking mtools frequently, the unblocking request
>>
>> s/unblocking/non-blocking/
>>
>> I would read 'unblocking' as a request that results in the
>> system becoming unblocked whereas non-blocking is more
>> commonly used and refers to function calls that will
>> not result in calling blocking system calls.
>>
> 
> OK, thanks  to point it out
> 
>> Indeed the NB in LOCK_NB stand for non-blocking.
>>
>>> caused race issue. Here is an example of syslinux
>>> [snip]
>>> dd if=/dev/zero of=floppy.img bs=1024 count=144
>>> losetup /dev/loop1 floppy.img
>>> mkdosfs /dev/loop1
>>> syslinux -i /dev/loop1
>>> |plain floppy: device "/proc/6351/fd/3" busy (Resource temporarily 
>>> unavailable):
>>> |Cannot initialize 'S:'
>>> |Bad target s:/ldlinux.sys
>>> [snip]
>>>
>>> The idea is from:
>>> https://bugzilla.redhat.com/show_bug.cgi?id=1235016
>>> https://groups.google.com/a/chromium.org/forum/#!msg/chromium-os-dev/bRPUCFHoBTQ/ZjB8kjjx1vUJ 
>>>
>>
>> I read though most of that and it seems that people think
>> that this may be a work-around. What do you think?
>>
>> If I were used to using mtools and it never blocked,
>> the I'd certainly be upset that we patched it to block.
>> lockdev.h gets used by:
>>
>> $ grep -r "lockdev.h" mtools-4.0.18/
>> mtools-4.0.18/plain_io.c:#include "lockdev.h"
>> mtools-4.0.18/floppyd.c:#include "lockdev.h"
>>
>> so until you can explain what the root cause of the
>> problem is more clearly, and why this change won't cause
>> problems for users of mtools, I think you should continue
>> to work on this problem.
>>
>> Or maybe the commit just needs a more details technical
>> explanation that summarizes the long thread that you linked
>> to...
>>
> 
>  From the thread, and my confirm, the last update of mtools is 2013-01-09,
> and Ubuntu 1604/1804 has the same issue on `syslinux -i /dev/loop1'.
> 
> With some digging on mtools, the user of mtools usually have a mtools.conf
> to customize it, and use `nolock' for specific device to workaround
> flock invoking (such as `drive c: file="/dev/sda1" nolock=1'). but 
> unfortunately
> syslinux does not follow the rule (it is hardly to know `/proc/***/fd/3' 
> before
> invoking syslinux )
> 
> [snip]
>   42         if(IS_NOLOCK(dev))
>   43                 return 0;
>   44
>   45 #if (defined(HAVE_FLOCK) && defined (LOCK_EX) && defined(LOCK_NB))
>   46         if (flock(fd, (mode ? LOCK_EX : LOCK_SH)) < 0)
> [snip]
> 
> On the other side, the error of `plain floppy: device "***" busy' 
> exactly comes
> from the error of flock invoking (not actual resource busy), so the fix 
> is safe
> for re-entry of mtools
> [snip]
>          /* lock the device on writes */
>          if (locked && lock_dev(This->fd, mode == O_RDWR, dev)) {
>                  if(errmsg)
> #ifdef HAVE_SNPRINTF
>                          snprintf(errmsg,199,
>                                  "plain floppy: device \"%s\" busy (%s):",
>                                  dev ? dev->name : "unknown", 
> strerror(errno));
> [snip]

Ok, thanks for explaining that.

> 
> I think long time no maintenance of mtools, and not to fix this 
> obviously issue.

Yeah, they don't even have a git repo for the project.

Thanks,
../Randy

> 
> //Hongxu
> 
>> ../Randy
>>
>>
>>>
>>> Signed-off-by: Hongxu Jia <hongxu.jia@windriver.com>
>>> ---
>>>   ...01-remove-LOCK_NB-to-use-blocking-request.patch | 44 
>>> ++++++++++++++++++++++
>>>   meta/recipes-devtools/mtools/mtools_4.0.18.bb      |  1 +
>>>   2 files changed, 45 insertions(+)
>>>   create mode 100644 
>>> meta/recipes-devtools/mtools/mtools/0001-remove-LOCK_NB-to-use-blocking-request.patch 
>>>
>>>
>>> diff --git 
>>> a/meta/recipes-devtools/mtools/mtools/0001-remove-LOCK_NB-to-use-blocking-request.patch 
>>> b/meta/recipes-devtools/mtools/mtools/0001-remove-LOCK_NB-to-use-blocking-request.patch 
>>>
>>> new file mode 100644
>>> index 0000000..47385a5
>>> --- /dev/null
>>> +++ 
>>> b/meta/recipes-devtools/mtools/mtools/0001-remove-LOCK_NB-to-use-blocking-request.patch 
>>>
>>> @@ -0,0 +1,44 @@
>>> +From 5bdbfe0a63fed48104b17412854b26ee2275869a Mon Sep 17 00:00:00 2001
>>> +From: Hongxu Jia <hongxu.jia@windriver.com>
>>> +Date: Wed, 22 Aug 2018 16:54:39 +0800
>>> +Subject: [PATCH] remove LOCK_NB to use blocking request
>>> +
>>> +While invoking mtools frequently, the unblocking request
>>> +caused race issue. Here is an example of syslinux
>>> +[snip]
>>> +dd if=/dev/zero of=floppy.img bs=1024 count=144
>>> +losetup /dev/loop1 floppy.img
>>> +mkdosfs /dev/loop1
>>> +syslinux -i /dev/loop1
>>> +|plain floppy: device "/proc/6351/fd/3" busy (Resource temporarily 
>>> unavailable):
>>> +|Cannot initialize 'S:'
>>> +|Bad target s:/ldlinux.sys
>>> +[snip]
>>> +
>>> +The idea is from:
>>> +https://bugzilla.redhat.com/show_bug.cgi?id=1235016
>>> +https://groups.google.com/a/chromium.org/forum/#!msg/chromium-os-dev/bRPUCFHoBTQ/ZjB8kjjx1vUJ 
>>>
>>> +
>>> +Upstream-Status: Pending
>>> +
>>> +Signed-off-by: Hongxu Jia <hongxu.jia@windriver.com>
>>> +---
>>> + lockdev.h | 2 +-
>>> + 1 file changed, 1 insertion(+), 1 deletion(-)
>>> +
>>> +diff --git a/lockdev.h b/lockdev.h
>>> +index 4467bc2..5a135ad 100644
>>> +--- a/lockdev.h
>>> ++++ b/lockdev.h
>>> +@@ -43,7 +43,7 @@ int lock_dev(int fd, int mode, struct device *dev)
>>> +         return 0;
>>> +
>>> + #if (defined(HAVE_FLOCK) && defined (LOCK_EX) && defined(LOCK_NB))
>>> +-    if (flock(fd, (mode ? LOCK_EX : LOCK_SH)|LOCK_NB) < 0)
>>> ++    if (flock(fd, (mode ? LOCK_EX : LOCK_SH)) < 0)
>>
>>> + #else /* FLOCK */
>>> +
>>> + #if (defined(HAVE_LOCKF) && defined(F_TLOCK))
>>> +--
>>> +2.7.4
>>> +
>>> diff --git a/meta/recipes-devtools/mtools/mtools_4.0.18.bb 
>>> b/meta/recipes-devtools/mtools/mtools_4.0.18.bb
>>> index dcd32ed..91f7b7c 100644
>>> --- a/meta/recipes-devtools/mtools/mtools_4.0.18.bb
>>> +++ b/meta/recipes-devtools/mtools/mtools_4.0.18.bb
>>> @@ -31,6 +31,7 @@ SRC_URI = "${GNU_MIRROR}/mtools/mtools-${PV}.tar.bz2 \
>>>              file://mtools-makeinfo.patch \
>>>              file://no-x11.gplv3.patch \
>>> file://0001-Continue-even-if-fs-size-is-not-divisible-by-sectors.patch \
>>> + file://0001-remove-LOCK_NB-to-use-blocking-request.patch \
>>>              "
>>>     SRC_URI_append_class-native = " 
>>> file://disable-hardcoded-configs.patch"
>>>
>>
>>
> 


-- 
# Randy MacLeod
# Wind River Linux