nfs-server-generator: handle 'noauto' mounts correctly.
diff mbox

Message ID 87poitv3p4.fsf@notabene.neil.brown.name
State New
Headers show

Commit Message

NeilBrown Feb. 8, 2017, 2:03 a.m. UTC
When this code was written, the systemd documentation stated
that "RequiresMountsFor" ignored mountpoints marked as "noauto".
Unfortunately this is incorrect.  Consquently a filesystem marked
as noauto that is also NFS exported will currently be mounted when
the NFS server is started. This is not what people expect.

So add a check for the noauto flag.  If any ancestor of a given
export point has the noauto flag, no RequiresMountsFor will be
generated for that point.

Also skip RequiresMountsFor for exports marked 'mountpoint', as their
absence is, theoretically, already handled by mountd.

URL: https://github.com/systemd/systemd/issues/5249
Signed-off-by: NeilBrown <neilb@suse.com>
---
 systemd/nfs-server-generator.c | 26 ++++++++++++++++++++++++++
 1 file changed, 26 insertions(+)

Comments

Steve Dickson Feb. 16, 2017, 10:23 a.m. UTC | #1
On 02/07/2017 09:03 PM, NeilBrown wrote:
> When this code was written, the systemd documentation stated
> that "RequiresMountsFor" ignored mountpoints marked as "noauto".
> Unfortunately this is incorrect.  Consquently a filesystem marked
> as noauto that is also NFS exported will currently be mounted when
> the NFS server is started. This is not what people expect.
>
> So add a check for the noauto flag.  If any ancestor of a given
> export point has the noauto flag, no RequiresMountsFor will be
> generated for that point.
>
> Also skip RequiresMountsFor for exports marked 'mountpoint', as their
> absence is, theoretically, already handled by mountd.
>
> URL: https://github.com/systemd/systemd/issues/5249
> Signed-off-by: NeilBrown <neilb@suse.com>
Committed...

steved.
> ---
>  systemd/nfs-server-generator.c | 26 ++++++++++++++++++++++++++
>  1 file changed, 26 insertions(+)
>
> diff --git a/systemd/nfs-server-generator.c b/systemd/nfs-server-generator.c
> index cc99969e9922..4aa65094ca07 100644
> --- a/systemd/nfs-server-generator.c
> +++ b/systemd/nfs-server-generator.c
> @@ -84,6 +84,28 @@ static void systemd_escape(FILE *f, char *path)
>  	}
>  }
>  
> +static int has_noauto_flag(char *path)
> +{
> +	FILE		*fstab;
> +	struct mntent	*mnt;
> +
> +	fstab = setmntent("/etc/fstab", "r");
> +	if (!fstab)
> +		return 0;
> +
> +	while ((mnt = getmntent(fstab)) != NULL) {
> +		int l = strlen(mnt->mnt_dir);
> +		if (strncmp(mnt->mnt_dir, path, l) != 0)
> +			continue;
> +		if (path[l] && path[l] != '/')
> +			continue;
> +		if (hasmntopt(mnt, "noauto"))
> +			break;
> +	}
> +	fclose(fstab);
> +	return mnt != NULL;
> +}
> +
>  int main(int argc, char *argv[])
>  {
>  	char		*path;
> @@ -124,6 +146,10 @@ int main(int argc, char *argv[])
>  		for (exp = exportlist[i].p_head; exp; exp = exp->m_next) {
>  			if (!is_unique(&list, exp->m_export.e_path))
>  				continue;
> +			if (exp->m_export.e_mountpoint)
> +				continue;
> +			if (has_noauto_flag(exp->m_export.e_path))
> +				continue;
>  			if (strchr(exp->m_export.e_path, ' '))
>  				fprintf(f, "RequiresMountsFor=\"%s\"\n",
>  					exp->m_export.e_path);

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ChunYu Wang April 4, 2017, 10:26 a.m. UTC | #2
Hi, Neil,

Thanks for your patch! But seems there still exists same problem on my
fedora 25 with a patched nfs-utils version, am I made something wrong
or we just need more patches for fedora family..?

-- I just try it with most simple steps:
[root@bootp-73-5-219 ~]# cat /etc/fstab |grep boot
UUID=932047db-24e7-4043-8373-6e87333b9ce1 /boot                   ext4
   noauto        1 2
^^ Set flag to 'noauto'

[root@bootp-73-5-219 ~]# umount /boot; mount -a; mountpoint /boot
/boot is not a mountpoint
^^ umount ready

[root@bootp-73-5-219 ~]# cat /lib/systemd/system/nfs-server.service |grep boot
RequiresMountsFor= /boot

[root@bootp-73-5-219 ~]# systemctl restart nfs-server

[root@bootp-73-5-219 ~]# mountpoint /boot/
/boot/ is a mountpoint
[root@bootp-73-5-219 ~]# mount |grep boot
/dev/sda1 on /boot type ext4 (rw,relatime,seclabel,data=ordered)
^^ mount again automatically
--

-- Already patched:
[root@bootp-73-5-219 ~]# rpm -q nfs-utils
nfs-utils-2.1.1-2.rc1.fc25.x86_64
[root@bootp-73-5-219 nfs-utils]# grep nfs-server-generator -r ./*.patch
./nfs-utils-2.1.2-rc1.patch:diff --git
a/systemd/nfs-server-generator.c b/systemd/nfs-server-generator.c
...
[root@bootp-73-5-219 nfs-utils]# cat ./nfs-utils.spec |grep -i patch001
Patch001: nfs-utils-2.1.2-rc1.patch
%patch001 -p1
--

Thanks,
ChunYu Wang





On Wed, Feb 8, 2017 at 10:03 AM, NeilBrown <neilb@suse.com> wrote:
>
> When this code was written, the systemd documentation stated
> that "RequiresMountsFor" ignored mountpoints marked as "noauto".
> Unfortunately this is incorrect.  Consquently a filesystem marked
> as noauto that is also NFS exported will currently be mounted when
> the NFS server is started. This is not what people expect.
>
> So add a check for the noauto flag.  If any ancestor of a given
> export point has the noauto flag, no RequiresMountsFor will be
> generated for that point.
>
> Also skip RequiresMountsFor for exports marked 'mountpoint', as their
> absence is, theoretically, already handled by mountd.
>
> URL: https://github.com/systemd/systemd/issues/5249
> Signed-off-by: NeilBrown <neilb@suse.com>
> ---
>  systemd/nfs-server-generator.c | 26 ++++++++++++++++++++++++++
>  1 file changed, 26 insertions(+)
>
> diff --git a/systemd/nfs-server-generator.c b/systemd/nfs-server-generator.c
> index cc99969e9922..4aa65094ca07 100644
> --- a/systemd/nfs-server-generator.c
> +++ b/systemd/nfs-server-generator.c
> @@ -84,6 +84,28 @@ static void systemd_escape(FILE *f, char *path)
>         }
>  }
>
> +static int has_noauto_flag(char *path)
> +{
> +       FILE            *fstab;
> +       struct mntent   *mnt;
> +
> +       fstab = setmntent("/etc/fstab", "r");
> +       if (!fstab)
> +               return 0;
> +
> +       while ((mnt = getmntent(fstab)) != NULL) {
> +               int l = strlen(mnt->mnt_dir);
> +               if (strncmp(mnt->mnt_dir, path, l) != 0)
> +                       continue;
> +               if (path[l] && path[l] != '/')
> +                       continue;
> +               if (hasmntopt(mnt, "noauto"))
> +                       break;
> +       }
> +       fclose(fstab);
> +       return mnt != NULL;
> +}
> +
>  int main(int argc, char *argv[])
>  {
>         char            *path;
> @@ -124,6 +146,10 @@ int main(int argc, char *argv[])
>                 for (exp = exportlist[i].p_head; exp; exp = exp->m_next) {
>                         if (!is_unique(&list, exp->m_export.e_path))
>                                 continue;
> +                       if (exp->m_export.e_mountpoint)
> +                               continue;
> +                       if (has_noauto_flag(exp->m_export.e_path))
> +                               continue;
>                         if (strchr(exp->m_export.e_path, ' '))
>                                 fprintf(f, "RequiresMountsFor=\"%s\"\n",
>                                         exp->m_export.e_path);
> --
> 2.11.0
>
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NeilBrown April 4, 2017, 9:57 p.m. UTC | #3
On Tue, Apr 04 2017, ChunYu Wang wrote:

> Hi, Neil,
>
> Thanks for your patch! But seems there still exists same problem on my
> fedora 25 with a patched nfs-utils version, am I made something wrong
> or we just need more patches for fedora family..?
>
> -- I just try it with most simple steps:
> [root@bootp-73-5-219 ~]# cat /etc/fstab |grep boot
> UUID=932047db-24e7-4043-8373-6e87333b9ce1 /boot                   ext4
>    noauto        1 2
> ^^ Set flag to 'noauto'
>
> [root@bootp-73-5-219 ~]# umount /boot; mount -a; mountpoint /boot
> /boot is not a mountpoint
> ^^ umount ready
>
> [root@bootp-73-5-219 ~]# cat /lib/systemd/system/nfs-server.service |grep boot
> RequiresMountsFor= /boot

Why do you have this line in this file?  This is what is causing /boot
to be mounted.
It seems that you don't understand the point of the patch.
The patch modifies the nfs-server systemd generator to *not* including
this line in the generated file if the noauto option is present.

NeilBrown


>
> [root@bootp-73-5-219 ~]# systemctl restart nfs-server
>
> [root@bootp-73-5-219 ~]# mountpoint /boot/
> /boot/ is a mountpoint
> [root@bootp-73-5-219 ~]# mount |grep boot
> /dev/sda1 on /boot type ext4 (rw,relatime,seclabel,data=ordered)
> ^^ mount again automatically
> --
>
> -- Already patched:
> [root@bootp-73-5-219 ~]# rpm -q nfs-utils
> nfs-utils-2.1.1-2.rc1.fc25.x86_64
> [root@bootp-73-5-219 nfs-utils]# grep nfs-server-generator -r ./*.patch
> ./nfs-utils-2.1.2-rc1.patch:diff --git
> a/systemd/nfs-server-generator.c b/systemd/nfs-server-generator.c
> ...
> [root@bootp-73-5-219 nfs-utils]# cat ./nfs-utils.spec |grep -i patch001
> Patch001: nfs-utils-2.1.2-rc1.patch
> %patch001 -p1
> --
>
> Thanks,
> ChunYu Wang
>
>
>
>
>
> On Wed, Feb 8, 2017 at 10:03 AM, NeilBrown <neilb@suse.com> wrote:
>>
>> When this code was written, the systemd documentation stated
>> that "RequiresMountsFor" ignored mountpoints marked as "noauto".
>> Unfortunately this is incorrect.  Consquently a filesystem marked
>> as noauto that is also NFS exported will currently be mounted when
>> the NFS server is started. This is not what people expect.
>>
>> So add a check for the noauto flag.  If any ancestor of a given
>> export point has the noauto flag, no RequiresMountsFor will be
>> generated for that point.
>>
>> Also skip RequiresMountsFor for exports marked 'mountpoint', as their
>> absence is, theoretically, already handled by mountd.
>>
>> URL: https://github.com/systemd/systemd/issues/5249
>> Signed-off-by: NeilBrown <neilb@suse.com>
>> ---
>>  systemd/nfs-server-generator.c | 26 ++++++++++++++++++++++++++
>>  1 file changed, 26 insertions(+)
>>
>> diff --git a/systemd/nfs-server-generator.c b/systemd/nfs-server-generator.c
>> index cc99969e9922..4aa65094ca07 100644
>> --- a/systemd/nfs-server-generator.c
>> +++ b/systemd/nfs-server-generator.c
>> @@ -84,6 +84,28 @@ static void systemd_escape(FILE *f, char *path)
>>         }
>>  }
>>
>> +static int has_noauto_flag(char *path)
>> +{
>> +       FILE            *fstab;
>> +       struct mntent   *mnt;
>> +
>> +       fstab = setmntent("/etc/fstab", "r");
>> +       if (!fstab)
>> +               return 0;
>> +
>> +       while ((mnt = getmntent(fstab)) != NULL) {
>> +               int l = strlen(mnt->mnt_dir);
>> +               if (strncmp(mnt->mnt_dir, path, l) != 0)
>> +                       continue;
>> +               if (path[l] && path[l] != '/')
>> +                       continue;
>> +               if (hasmntopt(mnt, "noauto"))
>> +                       break;
>> +       }
>> +       fclose(fstab);
>> +       return mnt != NULL;
>> +}
>> +
>>  int main(int argc, char *argv[])
>>  {
>>         char            *path;
>> @@ -124,6 +146,10 @@ int main(int argc, char *argv[])
>>                 for (exp = exportlist[i].p_head; exp; exp = exp->m_next) {
>>                         if (!is_unique(&list, exp->m_export.e_path))
>>                                 continue;
>> +                       if (exp->m_export.e_mountpoint)
>> +                               continue;
>> +                       if (has_noauto_flag(exp->m_export.e_path))
>> +                               continue;
>>                         if (strchr(exp->m_export.e_path, ' '))
>>                                 fprintf(f, "RequiresMountsFor=\"%s\"\n",
>>                                         exp->m_export.e_path);
>> --
>> 2.11.0
>>

Patch
diff mbox

diff --git a/systemd/nfs-server-generator.c b/systemd/nfs-server-generator.c
index cc99969e9922..4aa65094ca07 100644
--- a/systemd/nfs-server-generator.c
+++ b/systemd/nfs-server-generator.c
@@ -84,6 +84,28 @@  static void systemd_escape(FILE *f, char *path)
 	}
 }
 
+static int has_noauto_flag(char *path)
+{
+	FILE		*fstab;
+	struct mntent	*mnt;
+
+	fstab = setmntent("/etc/fstab", "r");
+	if (!fstab)
+		return 0;
+
+	while ((mnt = getmntent(fstab)) != NULL) {
+		int l = strlen(mnt->mnt_dir);
+		if (strncmp(mnt->mnt_dir, path, l) != 0)
+			continue;
+		if (path[l] && path[l] != '/')
+			continue;
+		if (hasmntopt(mnt, "noauto"))
+			break;
+	}
+	fclose(fstab);
+	return mnt != NULL;
+}
+
 int main(int argc, char *argv[])
 {
 	char		*path;
@@ -124,6 +146,10 @@  int main(int argc, char *argv[])
 		for (exp = exportlist[i].p_head; exp; exp = exp->m_next) {
 			if (!is_unique(&list, exp->m_export.e_path))
 				continue;
+			if (exp->m_export.e_mountpoint)
+				continue;
+			if (has_noauto_flag(exp->m_export.e_path))
+				continue;
 			if (strchr(exp->m_export.e_path, ' '))
 				fprintf(f, "RequiresMountsFor=\"%s\"\n",
 					exp->m_export.e_path);