* Re: [RFC PATCH] hugetlbfs: fix the hugetlbfs can not be mounted
@ 2016-11-03 19:17 ` Andrew Morton
0 siblings, 0 replies; 10+ messages in thread
From: Andrew Morton @ 2016-11-03 19:17 UTC (permalink / raw)
To: zhongjiang
Cc: nyc, n-horiguchi, mike.kravetz, rientjes, hillf.zj, linux-kernel,
linux-mm, Paul Gortmaker
On Sat, 29 Oct 2016 14:08:31 +0800 zhongjiang <zhongjiang@huawei.com> wrote:
> From: zhong jiang <zhongjiang@huawei.com>
>
> Since 'commit 3e89e1c5ea84 ("hugetlb: make mm and fs code explicitly non-modular")'
> bring in the mainline. mount hugetlbfs will result in the following issue.
>
> mount: unknown filesystme type 'hugetlbfs'
>
> because previous patch remove the module_alias_fs, when we mount the fs type,
> the caller get_fs_type can not find the filesystem.
>
> The patch just recover the module_alias_fs to identify the hugetlbfs.
hm, 3e89e1c5ea84 ("hugetlb: make mm and fs code explicitly
non-modular") was merged almost a year ago. And you are apparently the
first person to discover this regression. Can you think why that is?
> index 4fb7b10..b63e7de 100644
> --- a/fs/hugetlbfs/inode.c
> +++ b/fs/hugetlbfs/inode.c
> @@ -35,6 +35,7 @@
> #include <linux/security.h>
> #include <linux/magic.h>
> #include <linux/migrate.h>
> +#include <linux/module.h>
> #include <linux/uio.h>
>
> #include <asm/uaccess.h>
> @@ -1209,6 +1210,7 @@ static struct dentry *hugetlbfs_mount(struct file_system_type *fs_type,
> .mount = hugetlbfs_mount,
> .kill_sb = kill_litter_super,
> };
> +MODULE_ALIAS_FS("hugetlbfs");
>
> static struct vfsmount *hugetlbfs_vfsmount[HUGE_MAX_HSTATE];
>
--
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^ permalink raw reply [flat|nested] 10+ messages in thread* Re: [RFC PATCH] hugetlbfs: fix the hugetlbfs can not be mounted
2016-11-03 19:17 ` Andrew Morton
@ 2016-11-03 20:54 ` Paul Gortmaker
-1 siblings, 0 replies; 10+ messages in thread
From: Paul Gortmaker @ 2016-11-03 20:54 UTC (permalink / raw)
To: Andrew Morton
Cc: zhongjiang, nyc, n-horiguchi, mike.kravetz, rientjes, hillf.zj,
linux-kernel, linux-mm
[Re: [RFC PATCH] hugetlbfs: fix the hugetlbfs can not be mounted] On 03/11/2016 (Thu 12:17) Andrew Morton wrote:
> On Sat, 29 Oct 2016 14:08:31 +0800 zhongjiang <zhongjiang@huawei.com> wrote:
>
> > From: zhong jiang <zhongjiang@huawei.com>
> >
> > Since 'commit 3e89e1c5ea84 ("hugetlb: make mm and fs code explicitly non-modular")'
> > bring in the mainline. mount hugetlbfs will result in the following issue.
> >
> > mount: unknown filesystme type 'hugetlbfs'
The fact that the above has a typo makes me doubt it was real output
from "mount". In any case, that just means they didn't enable the
Kconfig option for it and hence it is not in /proc/filesystems as they
can easily verify.
> >
> > because previous patch remove the module_alias_fs, when we mount the fs type,
> > the caller get_fs_type can not find the filesystem.
> >
> > The patch just recover the module_alias_fs to identify the hugetlbfs.
>
> hm, 3e89e1c5ea84 ("hugetlb: make mm and fs code explicitly
> non-modular") was merged almost a year ago. And you are apparently the
> first person to discover this regression. Can you think why that is?
Agreed -- I'd like to know just how this conclusion was reached. Maybe
they are running some out-of-tree patches to make it modular? Who
knows. It would be nice if we hear back, but I don't have high hopes.
In any case, 3e89e1c5ea84 commit log says:
Also note that MODULE_ALIAS is a no-op for non-modular code.
This isn't fundamentally hard to verify; the macros are:
#define MODULE_ALIAS_FS(NAME) MODULE_ALIAS("fs-" NAME)
#define MODULE_ALIAS(_alias) MODULE_INFO(alias, _alias)
#define MODULE_INFO(tag, info) __MODULE_INFO(tag, tag, info)
...and then finally:
#ifdef MODULE
#define __MODULE_INFO(tag, name, info) \
static const char __UNIQUE_ID(name)[] \
__used __attribute__((section(".modinfo"), unused, aligned(1))) \
= __stringify(tag) "=" info
#else /* !MODULE */
/* This struct is here for syntactic coherency, it is not used */
#define __MODULE_INFO(tag, name, info) \
struct __UNIQUE_ID(name) {}
#endif
...so a commit like this would have to explain how the patch does anything in
the !MODULE case, when the syntax comment above even indicates it is not used.
I remember this commit since there was patch order issue that the kbuild
robot uncovered (as listed in the commit log) in an earlier version of it.
So I can assure the patch poster that hugetlbfs was mounted for testing,
and they should revisit the logic that led to this no-op patch.
Paul.
--
>
> > index 4fb7b10..b63e7de 100644
> > --- a/fs/hugetlbfs/inode.c
> > +++ b/fs/hugetlbfs/inode.c
> > @@ -35,6 +35,7 @@
> > #include <linux/security.h>
> > #include <linux/magic.h>
> > #include <linux/migrate.h>
> > +#include <linux/module.h>
> > #include <linux/uio.h>
> >
> > #include <asm/uaccess.h>
> > @@ -1209,6 +1210,7 @@ static struct dentry *hugetlbfs_mount(struct file_system_type *fs_type,
> > .mount = hugetlbfs_mount,
> > .kill_sb = kill_litter_super,
> > };
> > +MODULE_ALIAS_FS("hugetlbfs");
> >
> > static struct vfsmount *hugetlbfs_vfsmount[HUGE_MAX_HSTATE];
> >
>
^ permalink raw reply [flat|nested] 10+ messages in thread* Re: [RFC PATCH] hugetlbfs: fix the hugetlbfs can not be mounted
@ 2016-11-03 20:54 ` Paul Gortmaker
0 siblings, 0 replies; 10+ messages in thread
From: Paul Gortmaker @ 2016-11-03 20:54 UTC (permalink / raw)
To: Andrew Morton
Cc: zhongjiang, nyc, n-horiguchi, mike.kravetz, rientjes, hillf.zj,
linux-kernel, linux-mm
[Re: [RFC PATCH] hugetlbfs: fix the hugetlbfs can not be mounted] On 03/11/2016 (Thu 12:17) Andrew Morton wrote:
> On Sat, 29 Oct 2016 14:08:31 +0800 zhongjiang <zhongjiang@huawei.com> wrote:
>
> > From: zhong jiang <zhongjiang@huawei.com>
> >
> > Since 'commit 3e89e1c5ea84 ("hugetlb: make mm and fs code explicitly non-modular")'
> > bring in the mainline. mount hugetlbfs will result in the following issue.
> >
> > mount: unknown filesystme type 'hugetlbfs'
The fact that the above has a typo makes me doubt it was real output
from "mount". In any case, that just means they didn't enable the
Kconfig option for it and hence it is not in /proc/filesystems as they
can easily verify.
> >
> > because previous patch remove the module_alias_fs, when we mount the fs type,
> > the caller get_fs_type can not find the filesystem.
> >
> > The patch just recover the module_alias_fs to identify the hugetlbfs.
>
> hm, 3e89e1c5ea84 ("hugetlb: make mm and fs code explicitly
> non-modular") was merged almost a year ago. And you are apparently the
> first person to discover this regression. Can you think why that is?
Agreed -- I'd like to know just how this conclusion was reached. Maybe
they are running some out-of-tree patches to make it modular? Who
knows. It would be nice if we hear back, but I don't have high hopes.
In any case, 3e89e1c5ea84 commit log says:
Also note that MODULE_ALIAS is a no-op for non-modular code.
This isn't fundamentally hard to verify; the macros are:
#define MODULE_ALIAS_FS(NAME) MODULE_ALIAS("fs-" NAME)
#define MODULE_ALIAS(_alias) MODULE_INFO(alias, _alias)
#define MODULE_INFO(tag, info) __MODULE_INFO(tag, tag, info)
...and then finally:
#ifdef MODULE
#define __MODULE_INFO(tag, name, info) \
static const char __UNIQUE_ID(name)[] \
__used __attribute__((section(".modinfo"), unused, aligned(1))) \
= __stringify(tag) "=" info
#else /* !MODULE */
/* This struct is here for syntactic coherency, it is not used */
#define __MODULE_INFO(tag, name, info) \
struct __UNIQUE_ID(name) {}
#endif
...so a commit like this would have to explain how the patch does anything in
the !MODULE case, when the syntax comment above even indicates it is not used.
I remember this commit since there was patch order issue that the kbuild
robot uncovered (as listed in the commit log) in an earlier version of it.
So I can assure the patch poster that hugetlbfs was mounted for testing,
and they should revisit the logic that led to this no-op patch.
Paul.
--
>
> > index 4fb7b10..b63e7de 100644
> > --- a/fs/hugetlbfs/inode.c
> > +++ b/fs/hugetlbfs/inode.c
> > @@ -35,6 +35,7 @@
> > #include <linux/security.h>
> > #include <linux/magic.h>
> > #include <linux/migrate.h>
> > +#include <linux/module.h>
> > #include <linux/uio.h>
> >
> > #include <asm/uaccess.h>
> > @@ -1209,6 +1210,7 @@ static struct dentry *hugetlbfs_mount(struct file_system_type *fs_type,
> > .mount = hugetlbfs_mount,
> > .kill_sb = kill_litter_super,
> > };
> > +MODULE_ALIAS_FS("hugetlbfs");
> >
> > static struct vfsmount *hugetlbfs_vfsmount[HUGE_MAX_HSTATE];
> >
>
--
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^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [RFC PATCH] hugetlbfs: fix the hugetlbfs can not be mounted
2016-11-03 19:17 ` Andrew Morton
@ 2016-11-04 2:22 ` zhong jiang
-1 siblings, 0 replies; 10+ messages in thread
From: zhong jiang @ 2016-11-04 2:22 UTC (permalink / raw)
To: Andrew Morton
Cc: nyc, n-horiguchi, mike.kravetz, rientjes, hillf.zj, linux-kernel,
linux-mm, Paul Gortmaker
On 2016/11/4 3:17, Andrew Morton wrote:
> On Sat, 29 Oct 2016 14:08:31 +0800 zhongjiang <zhongjiang@huawei.com> wrote:
>
>> From: zhong jiang <zhongjiang@huawei.com>
>>
>> Since 'commit 3e89e1c5ea84 ("hugetlb: make mm and fs code explicitly non-modular")'
>> bring in the mainline. mount hugetlbfs will result in the following issue.
>>
>> mount: unknown filesystme type 'hugetlbfs'
>>
>> because previous patch remove the module_alias_fs, when we mount the fs type,
>> the caller get_fs_type can not find the filesystem.
>>
>> The patch just recover the module_alias_fs to identify the hugetlbfs.
> hm, 3e89e1c5ea84 ("hugetlb: make mm and fs code explicitly
> non-modular") was merged almost a year ago. And you are apparently the
> first person to discover this regression. Can you think why that is?
when I pull the upstream patch in 4.9-rc2. I find that I cannot mount the hugetlbfs.
but when I pull the upstream remain patch in the next day. I test again. it work well.
so I reply the mail right now, please ignore the patch. The detailed reason is not digged.
I am sorry for wasting your time.
Thanks you
zhongjiang
>> index 4fb7b10..b63e7de 100644
>> --- a/fs/hugetlbfs/inode.c
>> +++ b/fs/hugetlbfs/inode.c
>> @@ -35,6 +35,7 @@
>> #include <linux/security.h>
>> #include <linux/magic.h>
>> #include <linux/migrate.h>
>> +#include <linux/module.h>
>> #include <linux/uio.h>
>>
>> #include <asm/uaccess.h>
>> @@ -1209,6 +1210,7 @@ static struct dentry *hugetlbfs_mount(struct file_system_type *fs_type,
>> .mount = hugetlbfs_mount,
>> .kill_sb = kill_litter_super,
>> };
>> +MODULE_ALIAS_FS("hugetlbfs");
>>
>> static struct vfsmount *hugetlbfs_vfsmount[HUGE_MAX_HSTATE];
>>
>
> .
>
^ permalink raw reply [flat|nested] 10+ messages in thread* Re: [RFC PATCH] hugetlbfs: fix the hugetlbfs can not be mounted
@ 2016-11-04 2:22 ` zhong jiang
0 siblings, 0 replies; 10+ messages in thread
From: zhong jiang @ 2016-11-04 2:22 UTC (permalink / raw)
To: Andrew Morton
Cc: nyc, n-horiguchi, mike.kravetz, rientjes, hillf.zj, linux-kernel,
linux-mm, Paul Gortmaker
On 2016/11/4 3:17, Andrew Morton wrote:
> On Sat, 29 Oct 2016 14:08:31 +0800 zhongjiang <zhongjiang@huawei.com> wrote:
>
>> From: zhong jiang <zhongjiang@huawei.com>
>>
>> Since 'commit 3e89e1c5ea84 ("hugetlb: make mm and fs code explicitly non-modular")'
>> bring in the mainline. mount hugetlbfs will result in the following issue.
>>
>> mount: unknown filesystme type 'hugetlbfs'
>>
>> because previous patch remove the module_alias_fs, when we mount the fs type,
>> the caller get_fs_type can not find the filesystem.
>>
>> The patch just recover the module_alias_fs to identify the hugetlbfs.
> hm, 3e89e1c5ea84 ("hugetlb: make mm and fs code explicitly
> non-modular") was merged almost a year ago. And you are apparently the
> first person to discover this regression. Can you think why that is?
when I pull the upstream patch in 4.9-rc2. I find that I cannot mount the hugetlbfs.
but when I pull the upstream remain patch in the next day. I test again. it work well.
so I reply the mail right now, please ignore the patch. The detailed reason is not digged.
I am sorry for wasting your time.
Thanks you
zhongjiang
>> index 4fb7b10..b63e7de 100644
>> --- a/fs/hugetlbfs/inode.c
>> +++ b/fs/hugetlbfs/inode.c
>> @@ -35,6 +35,7 @@
>> #include <linux/security.h>
>> #include <linux/magic.h>
>> #include <linux/migrate.h>
>> +#include <linux/module.h>
>> #include <linux/uio.h>
>>
>> #include <asm/uaccess.h>
>> @@ -1209,6 +1210,7 @@ static struct dentry *hugetlbfs_mount(struct file_system_type *fs_type,
>> .mount = hugetlbfs_mount,
>> .kill_sb = kill_litter_super,
>> };
>> +MODULE_ALIAS_FS("hugetlbfs");
>>
>> static struct vfsmount *hugetlbfs_vfsmount[HUGE_MAX_HSTATE];
>>
>
> .
>
--
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^ permalink raw reply [flat|nested] 10+ messages in thread