[PATCH 1/2] documentation: split and build smount.c

[PATCH 1/2] documentation: split and build smount.c

[Randy Dunlap]

From: Randy Dunlap <randy.dunlap@oracle.com>

Make smount.c source file and add that to Makefile so that its
build can be checked.

Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
cc: Miklos Szeredi <miklos@szeredi.hu>
---
 Documentation/Makefile                      |    2 
 Documentation/filesystems/00-INDEX          |    2 
 Documentation/filesystems/Makefile          |    8 ++
 Documentation/filesystems/sharedsubtree.txt |   82 +---------------------------
 Documentation/filesystems/smount.c          |   73 ++++++++++++++++++++++++
 5 files changed, 88 insertions(+), 79 deletions(-)

--- /dev/null
+++ lin2627-rc3g4-kerndoc/Documentation/filesystems/smount.c
@@ -0,0 +1,73 @@
+//
+//this code was developed my Miklos Szeredi <miklos@szeredi.hu>
+//and modified by Ram Pai <linuxram@us.ibm.com>
+// sample usage:
+//              smount /tmp shared
+//
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <string.h>
+#include <sys/mount.h>
+#include <sys/fsuid.h>
+
+#ifndef MS_REC
+#define MS_REC		0x4000	/* 16384: Recursive loopback */
+#endif
+
+#ifndef MS_SHARED
+#define MS_SHARED		1<<20	/* Shared */
+#endif
+
+#ifndef MS_PRIVATE
+#define MS_PRIVATE		1<<18	/* Private */
+#endif
+
+#ifndef MS_SLAVE
+#define MS_SLAVE		1<<19	/* Slave */
+#endif
+
+#ifndef MS_UNBINDABLE
+#define MS_UNBINDABLE		1<<17	/* Unbindable */
+#endif
+
+int main(int argc, char *argv[])
+{
+	int type;
+	if(argc != 3) {
+		fprintf(stderr, "usage: %s dir "
+		"<rshared|rslave|rprivate|runbindable|shared|slave"
+		"|private|unbindable>\n" , argv[0]);
+		return 1;
+	}
+
+	fprintf(stdout, "%s %s %s\n", argv[0], argv[1], argv[2]);
+
+	if (strcmp(argv[2],"rshared")==0)
+		type=(MS_SHARED|MS_REC);
+	else if (strcmp(argv[2],"rslave")==0)
+		type=(MS_SLAVE|MS_REC);
+	else if (strcmp(argv[2],"rprivate")==0)
+		type=(MS_PRIVATE|MS_REC);
+	else if (strcmp(argv[2],"runbindable")==0)
+		type=(MS_UNBINDABLE|MS_REC);
+	else if (strcmp(argv[2],"shared")==0)
+		type=MS_SHARED;
+	else if (strcmp(argv[2],"slave")==0)
+		type=MS_SLAVE;
+	else if (strcmp(argv[2],"private")==0)
+		type=MS_PRIVATE;
+	else if (strcmp(argv[2],"unbindable")==0)
+		type=MS_UNBINDABLE;
+	else {
+		fprintf(stderr, "invalid operation: %s\n", argv[2]);
+		return 1;
+	}
+	setfsuid(getuid());
+
+	if(mount("", argv[1], "dontcare", type, "") == -1) {
+		perror("mount");
+		return 1;
+	}
+	return 0;
+}
--- lin2627-rc3g4-kerndoc.orig/Documentation/filesystems/sharedsubtree.txt
+++ lin2627-rc3g4-kerndoc/Documentation/filesystems/sharedsubtree.txt
@@ -47,6 +47,7 @@ replicas continue to be exactly same.
 	note: mount command does not yet support the --make-shared flag.
 	I have included a small C program which does the same by executing
 	'smount /mnt shared'
+	[see Documentation/filesystems/smount.c]
 
 	#mount --bind /mnt /tmp
 	The above command replicates the mount at /mnt to the mountpoint /tmp
@@ -141,87 +142,12 @@ replicas continue to be exactly same.
 
 	Currently the mount command is not aware of shared subtree features.
 	Work is in progress to add the support in mount ( util-linux package ).
-	Till then use the following program.
+	Until then use the 'smount' program that is located in
+	"Documentation/filesystems/smount.c" and build it like:
 
-	------------------------------------------------------------------------
-	//
-	//this code was developed my Miklos Szeredi <miklos@szeredi.hu>
-	//and modified by Ram Pai <linuxram@us.ibm.com>
-	// sample usage:
-	//              smount /tmp shared
-	//
-	#include <stdio.h>
-	#include <stdlib.h>
-	#include <unistd.h>
-	#include <string.h>
-	#include <sys/mount.h>
-	#include <sys/fsuid.h>
-
-	#ifndef MS_REC
-	#define MS_REC		0x4000	/* 16384: Recursive loopback */
-	#endif
-
-	#ifndef MS_SHARED
-	#define MS_SHARED		1<<20	/* Shared */
-	#endif
-
-	#ifndef MS_PRIVATE
-	#define MS_PRIVATE		1<<18	/* Private */
-	#endif
-
-	#ifndef MS_SLAVE
-	#define MS_SLAVE		1<<19	/* Slave */
-	#endif
-
-	#ifndef MS_UNBINDABLE
-	#define MS_UNBINDABLE		1<<17	/* Unbindable */
-	#endif
-
-	int main(int argc, char *argv[])
-	{
-		int type;
-		if(argc != 3) {
-			fprintf(stderr, "usage: %s dir "
-			"<rshared|rslave|rprivate|runbindable|shared|slave"
-			"|private|unbindable>\n" , argv[0]);
-			return 1;
-		}
-
-		fprintf(stdout, "%s %s %s\n", argv[0], argv[1], argv[2]);
-
-		if (strcmp(argv[2],"rshared")==0)
-			type=(MS_SHARED|MS_REC);
-		else if (strcmp(argv[2],"rslave")==0)
-			type=(MS_SLAVE|MS_REC);
-		else if (strcmp(argv[2],"rprivate")==0)
-			type=(MS_PRIVATE|MS_REC);
-		else if (strcmp(argv[2],"runbindable")==0)
-			type=(MS_UNBINDABLE|MS_REC);
-		else if (strcmp(argv[2],"shared")==0)
-			type=MS_SHARED;
-		else if (strcmp(argv[2],"slave")==0)
-			type=MS_SLAVE;
-		else if (strcmp(argv[2],"private")==0)
-			type=MS_PRIVATE;
-		else if (strcmp(argv[2],"unbindable")==0)
-			type=MS_UNBINDABLE;
-		else {
-			fprintf(stderr, "invalid operation: %s\n", argv[2]);
-			return 1;
-		}
-		setfsuid(getuid());
-
-		if(mount("", argv[1], "dontcare", type, "") == -1) {
-			perror("mount");
-			return 1;
-		}
-		return 0;
-	}
-	-----------------------------------------------------------------------
-
-	Copy the above code snippet into smount.c
 	gcc -o smount smount.c
 
+	-----------------------------------------------------------------------
 
 	(i) To mark all the mounts under /mnt as shared execute the following
 	command:
--- lin2627-rc3g4-kerndoc.orig/Documentation/Makefile
+++ lin2627-rc3g4-kerndoc/Documentation/Makefile
@@ -1,3 +1,3 @@
 obj-m := DocBook/ accounting/ auxdisplay/ connector/ \
-	filesystems/configfs/ ia64/ networking/ \
+	filesystems/ filesystems/configfs/ ia64/ networking/ \
 	pcmcia/ spi/ video4linux/ vm/ watchdog/src/
--- /dev/null
+++ lin2627-rc3g4-kerndoc/Documentation/filesystems/Makefile
@@ -0,0 +1,8 @@
+# kbuild trick to avoid linker error. Can be omitted if a module is built.
+obj- := dummy.o
+
+# List of programs to build
+hostprogs-y := smount
+
+# Tell kbuild to always build the programs
+always := $(hostprogs-y)
--- lin2627-rc3g4-kerndoc.orig/Documentation/filesystems/00-INDEX
+++ lin2627-rc3g4-kerndoc/Documentation/filesystems/00-INDEX
@@ -92,6 +92,8 @@ sharedsubtree.txt
 	- a description of shared subtrees for namespaces.
 smbfs.txt
 	- info on using filesystems with the SMB protocol (Win 3.11 and NT).
+smount.c
+	- sample source code for mounting shared subtrees
 spufs.txt
 	- info and mount options for the SPU filesystem used on Cell.
 sysfs-pci.txt


---
~Randy
Linux Plumbers Conference, 17-19 September 2008, Portland, Oregon USA
http://linuxplumbersconf.org/

Re: [PATCH 1/2] documentation: split and build smount.c

[Christoph Hellwig]

On Sun, Aug 17, 2008 at 09:44:42PM -0700, Randy Dunlap wrote:
> From: Randy Dunlap <randy.dunlap@oracle.com>
> 
> Make smount.c source file and add that to Makefile so that its
> build can be checked.

Just remove it, and modern /bin/mount handles shared subtrees just fine

> 
> Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
> cc: Miklos Szeredi <miklos@szeredi.hu>
> ---
>  Documentation/Makefile                      |    2 
>  Documentation/filesystems/00-INDEX          |    2 
>  Documentation/filesystems/Makefile          |    8 ++
>  Documentation/filesystems/sharedsubtree.txt |   82 +---------------------------
>  Documentation/filesystems/smount.c          |   73 ++++++++++++++++++++++++
>  5 files changed, 88 insertions(+), 79 deletions(-)
> 
> --- /dev/null
> +++ lin2627-rc3g4-kerndoc/Documentation/filesystems/smount.c
> @@ -0,0 +1,73 @@
> +//
> +//this code was developed my Miklos Szeredi <miklos@szeredi.hu>
> +//and modified by Ram Pai <linuxram@us.ibm.com>
> +// sample usage:
> +//              smount /tmp shared
> +//
> +#include <stdio.h>
> +#include <stdlib.h>
> +#include <unistd.h>
> +#include <string.h>
> +#include <sys/mount.h>
> +#include <sys/fsuid.h>
> +
> +#ifndef MS_REC
> +#define MS_REC		0x4000	/* 16384: Recursive loopback */
> +#endif
> +
> +#ifndef MS_SHARED
> +#define MS_SHARED		1<<20	/* Shared */
> +#endif
> +
> +#ifndef MS_PRIVATE
> +#define MS_PRIVATE		1<<18	/* Private */
> +#endif
> +
> +#ifndef MS_SLAVE
> +#define MS_SLAVE		1<<19	/* Slave */
> +#endif
> +
> +#ifndef MS_UNBINDABLE
> +#define MS_UNBINDABLE		1<<17	/* Unbindable */
> +#endif
> +
> +int main(int argc, char *argv[])
> +{
> +	int type;
> +	if(argc != 3) {
> +		fprintf(stderr, "usage: %s dir "
> +		"<rshared|rslave|rprivate|runbindable|shared|slave"
> +		"|private|unbindable>\n" , argv[0]);
> +		return 1;
> +	}
> +
> +	fprintf(stdout, "%s %s %s\n", argv[0], argv[1], argv[2]);
> +
> +	if (strcmp(argv[2],"rshared")==0)
> +		type=(MS_SHARED|MS_REC);
> +	else if (strcmp(argv[2],"rslave")==0)
> +		type=(MS_SLAVE|MS_REC);
> +	else if (strcmp(argv[2],"rprivate")==0)
> +		type=(MS_PRIVATE|MS_REC);
> +	else if (strcmp(argv[2],"runbindable")==0)
> +		type=(MS_UNBINDABLE|MS_REC);
> +	else if (strcmp(argv[2],"shared")==0)
> +		type=MS_SHARED;
> +	else if (strcmp(argv[2],"slave")==0)
> +		type=MS_SLAVE;
> +	else if (strcmp(argv[2],"private")==0)
> +		type=MS_PRIVATE;
> +	else if (strcmp(argv[2],"unbindable")==0)
> +		type=MS_UNBINDABLE;
> +	else {
> +		fprintf(stderr, "invalid operation: %s\n", argv[2]);
> +		return 1;
> +	}
> +	setfsuid(getuid());
> +
> +	if(mount("", argv[1], "dontcare", type, "") == -1) {
> +		perror("mount");
> +		return 1;
> +	}
> +	return 0;
> +}
> --- lin2627-rc3g4-kerndoc.orig/Documentation/filesystems/sharedsubtree.txt
> +++ lin2627-rc3g4-kerndoc/Documentation/filesystems/sharedsubtree.txt
> @@ -47,6 +47,7 @@ replicas continue to be exactly same.
>  	note: mount command does not yet support the --make-shared flag.
>  	I have included a small C program which does the same by executing
>  	'smount /mnt shared'
> +	[see Documentation/filesystems/smount.c]
>  
>  	#mount --bind /mnt /tmp
>  	The above command replicates the mount at /mnt to the mountpoint /tmp
> @@ -141,87 +142,12 @@ replicas continue to be exactly same.
>  
>  	Currently the mount command is not aware of shared subtree features.
>  	Work is in progress to add the support in mount ( util-linux package ).
> -	Till then use the following program.
> +	Until then use the 'smount' program that is located in
> +	"Documentation/filesystems/smount.c" and build it like:
>  
> -	------------------------------------------------------------------------
> -	//
> -	//this code was developed my Miklos Szeredi <miklos@szeredi.hu>
> -	//and modified by Ram Pai <linuxram@us.ibm.com>
> -	// sample usage:
> -	//              smount /tmp shared
> -	//
> -	#include <stdio.h>
> -	#include <stdlib.h>
> -	#include <unistd.h>
> -	#include <string.h>
> -	#include <sys/mount.h>
> -	#include <sys/fsuid.h>
> -
> -	#ifndef MS_REC
> -	#define MS_REC		0x4000	/* 16384: Recursive loopback */
> -	#endif
> -
> -	#ifndef MS_SHARED
> -	#define MS_SHARED		1<<20	/* Shared */
> -	#endif
> -
> -	#ifndef MS_PRIVATE
> -	#define MS_PRIVATE		1<<18	/* Private */
> -	#endif
> -
> -	#ifndef MS_SLAVE
> -	#define MS_SLAVE		1<<19	/* Slave */
> -	#endif
> -
> -	#ifndef MS_UNBINDABLE
> -	#define MS_UNBINDABLE		1<<17	/* Unbindable */
> -	#endif
> -
> -	int main(int argc, char *argv[])
> -	{
> -		int type;
> -		if(argc != 3) {
> -			fprintf(stderr, "usage: %s dir "
> -			"<rshared|rslave|rprivate|runbindable|shared|slave"
> -			"|private|unbindable>\n" , argv[0]);
> -			return 1;
> -		}
> -
> -		fprintf(stdout, "%s %s %s\n", argv[0], argv[1], argv[2]);
> -
> -		if (strcmp(argv[2],"rshared")==0)
> -			type=(MS_SHARED|MS_REC);
> -		else if (strcmp(argv[2],"rslave")==0)
> -			type=(MS_SLAVE|MS_REC);
> -		else if (strcmp(argv[2],"rprivate")==0)
> -			type=(MS_PRIVATE|MS_REC);
> -		else if (strcmp(argv[2],"runbindable")==0)
> -			type=(MS_UNBINDABLE|MS_REC);
> -		else if (strcmp(argv[2],"shared")==0)
> -			type=MS_SHARED;
> -		else if (strcmp(argv[2],"slave")==0)
> -			type=MS_SLAVE;
> -		else if (strcmp(argv[2],"private")==0)
> -			type=MS_PRIVATE;
> -		else if (strcmp(argv[2],"unbindable")==0)
> -			type=MS_UNBINDABLE;
> -		else {
> -			fprintf(stderr, "invalid operation: %s\n", argv[2]);
> -			return 1;
> -		}
> -		setfsuid(getuid());
> -
> -		if(mount("", argv[1], "dontcare", type, "") == -1) {
> -			perror("mount");
> -			return 1;
> -		}
> -		return 0;
> -	}
> -	-----------------------------------------------------------------------
> -
> -	Copy the above code snippet into smount.c
>  	gcc -o smount smount.c
>  
> +	-----------------------------------------------------------------------
>  
>  	(i) To mark all the mounts under /mnt as shared execute the following
>  	command:
> --- lin2627-rc3g4-kerndoc.orig/Documentation/Makefile
> +++ lin2627-rc3g4-kerndoc/Documentation/Makefile
> @@ -1,3 +1,3 @@
>  obj-m := DocBook/ accounting/ auxdisplay/ connector/ \
> -	filesystems/configfs/ ia64/ networking/ \
> +	filesystems/ filesystems/configfs/ ia64/ networking/ \
>  	pcmcia/ spi/ video4linux/ vm/ watchdog/src/
> --- /dev/null
> +++ lin2627-rc3g4-kerndoc/Documentation/filesystems/Makefile
> @@ -0,0 +1,8 @@
> +# kbuild trick to avoid linker error. Can be omitted if a module is built.
> +obj- := dummy.o
> +
> +# List of programs to build
> +hostprogs-y := smount
> +
> +# Tell kbuild to always build the programs
> +always := $(hostprogs-y)
> --- lin2627-rc3g4-kerndoc.orig/Documentation/filesystems/00-INDEX
> +++ lin2627-rc3g4-kerndoc/Documentation/filesystems/00-INDEX
> @@ -92,6 +92,8 @@ sharedsubtree.txt
>  	- a description of shared subtrees for namespaces.
>  smbfs.txt
>  	- info on using filesystems with the SMB protocol (Win 3.11 and NT).
> +smount.c
> +	- sample source code for mounting shared subtrees
>  spufs.txt
>  	- info and mount options for the SPU filesystem used on Cell.
>  sysfs-pci.txt
> 
> 
> ---
> ~Randy
> Linux Plumbers Conference, 17-19 September 2008, Portland, Oregon USA
> http://linuxplumbersconf.org/
> --
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at  http://www.tux.org/lkml/
---end quoted text---

[PATCH v2] documentation: split and build smount.c

[Randy Dunlap]

On Mon, 18 Aug 2008 01:04:31 -0400 Christoph Hellwig wrote:

> Just remove it, and modern /bin/mount handles shared subtrees just fine

Miklos... ?

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
From: Randy Dunlap <randy.dunlap@oracle.com>

mount(8) handles shared subtrees just fine, so remove the smount
program from Documentation/filesystems/sharedsubtree.txt.

Fix annoying "Lets" -> "Let's".

Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
cc: Miklos Szeredi <miklos@szeredi.hu>
---
 Documentation/filesystems/sharedsubtree.txt |  192 +++-------------------------
 1 file changed, 25 insertions(+), 167 deletions(-)

--- lin2627-rc3g4-kerndoc.orig/Documentation/filesystems/sharedsubtree.txt
+++ lin2627-rc3g4-kerndoc/Documentation/filesystems/sharedsubtree.txt
@@ -41,12 +41,11 @@ replicas continue to be exactly same.
 
 	Here is an example:
 
-	Lets say /mnt has a mount that is shared.
+	Let's say /mnt has a mount that is shared.
 	mount --make-shared /mnt
 
-	note: mount command does not yet support the --make-shared flag.
-	I have included a small C program which does the same by executing
-	'smount /mnt shared'
+	Note: mount(8) command now supports the --make-shared flag,
+	so the sample 'smount' program is no longer needed.
 
 	#mount --bind /mnt /tmp
 	The above command replicates the mount at /mnt to the mountpoint /tmp
@@ -58,7 +57,7 @@ replicas continue to be exactly same.
 	#ls /tmp
 	a b c
 
-	Now lets say we mount a device at /tmp/a
+	Now let's say we mount a device at /tmp/a
 	#mount /dev/sd0  /tmp/a
 
 	#ls /tmp/a
@@ -80,20 +79,19 @@ replicas continue to be exactly same.
 
 	Here is an example:
 
-	Lets say /mnt has a mount which is shared.
+	Let's say /mnt has a mount which is shared.
 	#mount --make-shared /mnt
 
-	Lets bind mount /mnt to /tmp
+	Let's bind mount /mnt to /tmp
 	#mount --bind /mnt /tmp
 
 	the new mount at /tmp becomes a shared mount and it is a replica of
 	the mount at /mnt.
 
-	Now lets make the mount at /tmp; a slave of /mnt
+	Now let's make the mount at /tmp; a slave of /mnt
 	#mount --make-slave /tmp
-	[or smount /tmp slave]
 
-	lets mount /dev/sd0 on /mnt/a
+	let's mount /dev/sd0 on /mnt/a
 	#mount /dev/sd0 /mnt/a
 
 	#ls /mnt/a
@@ -104,7 +102,7 @@ replicas continue to be exactly same.
 
 	Note the mount event has propagated to the mount at /tmp
 
-	However lets see what happens if we mount something on the mount at /tmp
+	However let's see what happens if we mount something on the mount at /tmp
 
 	#mount /dev/sd1 /tmp/b
 
@@ -124,12 +122,11 @@ replicas continue to be exactly same.
 
 2d) A unbindable mount is a unbindable private mount
 
-	lets say we have a mount at /mnt and we make is unbindable
+	let's say we have a mount at /mnt and we make is unbindable
 
 	#mount --make-unbindable /mnt
-	 [ smount /mnt  unbindable ]
 
-	 Lets try to bind mount this mount somewhere else.
+	 Let's try to bind mount this mount somewhere else.
 	 # mount --bind /mnt /tmp
 	 mount: wrong fs type, bad option, bad superblock on /mnt,
 	        or too many mounted file systems
@@ -139,147 +136,8 @@ replicas continue to be exactly same.
 
 3) smount command
 
-	Currently the mount command is not aware of shared subtree features.
-	Work is in progress to add the support in mount ( util-linux package ).
-	Till then use the following program.
-
-	------------------------------------------------------------------------
-	//
-	//this code was developed my Miklos Szeredi <miklos@szeredi.hu>
-	//and modified by Ram Pai <linuxram@us.ibm.com>
-	// sample usage:
-	//              smount /tmp shared
-	//
-	#include <stdio.h>
-	#include <stdlib.h>
-	#include <unistd.h>
-	#include <string.h>
-	#include <sys/mount.h>
-	#include <sys/fsuid.h>
-
-	#ifndef MS_REC
-	#define MS_REC		0x4000	/* 16384: Recursive loopback */
-	#endif
-
-	#ifndef MS_SHARED
-	#define MS_SHARED		1<<20	/* Shared */
-	#endif
-
-	#ifndef MS_PRIVATE
-	#define MS_PRIVATE		1<<18	/* Private */
-	#endif
-
-	#ifndef MS_SLAVE
-	#define MS_SLAVE		1<<19	/* Slave */
-	#endif
-
-	#ifndef MS_UNBINDABLE
-	#define MS_UNBINDABLE		1<<17	/* Unbindable */
-	#endif
-
-	int main(int argc, char *argv[])
-	{
-		int type;
-		if(argc != 3) {
-			fprintf(stderr, "usage: %s dir "
-			"<rshared|rslave|rprivate|runbindable|shared|slave"
-			"|private|unbindable>\n" , argv[0]);
-			return 1;
-		}
-
-		fprintf(stdout, "%s %s %s\n", argv[0], argv[1], argv[2]);
-
-		if (strcmp(argv[2],"rshared")==0)
-			type=(MS_SHARED|MS_REC);
-		else if (strcmp(argv[2],"rslave")==0)
-			type=(MS_SLAVE|MS_REC);
-		else if (strcmp(argv[2],"rprivate")==0)
-			type=(MS_PRIVATE|MS_REC);
-		else if (strcmp(argv[2],"runbindable")==0)
-			type=(MS_UNBINDABLE|MS_REC);
-		else if (strcmp(argv[2],"shared")==0)
-			type=MS_SHARED;
-		else if (strcmp(argv[2],"slave")==0)
-			type=MS_SLAVE;
-		else if (strcmp(argv[2],"private")==0)
-			type=MS_PRIVATE;
-		else if (strcmp(argv[2],"unbindable")==0)
-			type=MS_UNBINDABLE;
-		else {
-			fprintf(stderr, "invalid operation: %s\n", argv[2]);
-			return 1;
-		}
-		setfsuid(getuid());
-
-		if(mount("", argv[1], "dontcare", type, "") == -1) {
-			perror("mount");
-			return 1;
-		}
-		return 0;
-	}
-	-----------------------------------------------------------------------
-
-	Copy the above code snippet into smount.c
-	gcc -o smount smount.c
-
-
-	(i) To mark all the mounts under /mnt as shared execute the following
-	command:
-
-	 	smount /mnt rshared
-		the corresponding syntax planned for mount command is
-		mount --make-rshared /mnt
-
-	    just to mark a mount /mnt as shared, execute the following
-	    command:
-	 	smount /mnt shared
-		the corresponding syntax planned for mount command is
-		mount --make-shared /mnt
-
-	(ii) To mark all the shared mounts under /mnt as slave execute the
-	following
-
-	     command:
-		smount /mnt rslave
-		the corresponding syntax planned for mount command is
-		mount --make-rslave /mnt
-
-	    just to mark a mount /mnt as slave, execute the following
-	    command:
-	 	smount /mnt slave
-		the corresponding syntax planned for mount command is
-		mount --make-slave /mnt
-
-	(iii) To mark all the mounts under /mnt as private execute the
-	following command:
-
-		smount /mnt rprivate
-		the corresponding syntax planned for mount command is
-		mount --make-rprivate /mnt
-
-	    just to mark a mount /mnt as private, execute the following
-	    command:
-	 	smount /mnt private
-		the corresponding syntax planned for mount command is
-		mount --make-private /mnt
-
-	      NOTE: by default all the mounts are created as private. But if
-	      you want to change some shared/slave/unbindable  mount as
-	      private at a later point in time, this command can help.
-
-	(iv) To mark all the mounts under /mnt as unbindable execute the
-	following
-
-	     command:
-		smount /mnt runbindable
-		the corresponding syntax planned for mount command is
-		mount --make-runbindable /mnt
-
-	    just to mark a mount /mnt as unbindable, execute the following
-	    command:
-	 	smount /mnt unbindable
-		the corresponding syntax planned for mount command is
-		mount --make-unbindable /mnt
+	Modern mount(8) command is aware of shared subtree features,
+	so use it instead of the 'smount' command. [source code removed]
 
 
 4) Use cases
@@ -558,7 +416,7 @@ replicas continue to be exactly same.
 	then the subtree under the unbindable mount is pruned in the new
 	location.
 
-	eg: lets say we have the following mount tree.
+	eg: let's say we have the following mount tree.
 
 		A
 	      /   \
@@ -566,7 +424,7 @@ replicas continue to be exactly same.
 	     / \ / \
 	     D E F G
 
-	     Lets say all the mount except the mount C in the tree are
+	     Let's say all the mount except the mount C in the tree are
 	     of a type other than unbindable.
 
 	     If this tree is rbound to say Z
@@ -683,13 +541,13 @@ replicas continue to be exactly same.
 	'b' on mounts that receive propagation from mount 'B' and does not have
 	sub-mounts within them are unmounted.
 
-	Example: Lets say 'B1', 'B2', 'B3' are shared mounts that propagate to
+	Example: Let's say 'B1', 'B2', 'B3' are shared mounts that propagate to
 	each other.
 
-	lets say 'A1', 'A2', 'A3' are first mounted at dentry 'b' on mount
+	let's say 'A1', 'A2', 'A3' are first mounted at dentry 'b' on mount
 	'B1', 'B2' and 'B3' respectively.
 
-	lets say 'C1', 'C2', 'C3' are next mounted at the same dentry 'b' on
+	let's say 'C1', 'C2', 'C3' are next mounted at the same dentry 'b' on
 	mount 'B1', 'B2' and 'B3' respectively.
 
 	if 'C1' is unmounted, all the mounts that are most-recently-mounted on
@@ -710,7 +568,7 @@ replicas continue to be exactly same.
 	A cloned namespace contains all the mounts as that of the parent
 	namespace.
 
-	Lets say 'A' and 'B' are the corresponding mounts in the parent and the
+	Let's say 'A' and 'B' are the corresponding mounts in the parent and the
 	child namespace.
 
 	If 'A' is shared, then 'B' is also shared and 'A' and 'B' propagate to
@@ -759,11 +617,11 @@ replicas continue to be exactly same.
 		mount --make-slave /mnt
 
 		At this point we have the first mount at /tmp and
-		its root dentry is 1. Lets call this mount 'A'
+		its root dentry is 1. Let's call this mount 'A'
 		And then we have a second mount at /tmp1 with root
-		dentry 2. Lets call this mount 'B'
+		dentry 2. Let's call this mount 'B'
 		Next we have a third mount at /mnt with root dentry
-		mnt. Lets call this mount 'C'
+		mnt. Let's call this mount 'C'
 
 		'B' is the slave of 'A' and 'C' is a slave of 'B'
 		A -> B -> C
@@ -794,7 +652,7 @@ replicas continue to be exactly same.
 
 	Q3 Why is unbindable mount needed?
 
-		Lets say we want to replicate the mount tree at multiple
+		Let's say we want to replicate the mount tree at multiple
 		locations within the same subtree.
 
 		if one rbind mounts a tree within the same subtree 'n' times
@@ -803,7 +661,7 @@ replicas continue to be exactly same.
 		mounts. Here is a example.
 
 		step 1:
-		   lets say the root tree has just two directories with
+		   let's say the root tree has just two directories with
 		   one vfsmount.
 				    root
 				   /    \
@@ -875,7 +733,7 @@ replicas continue to be exactly same.
 		Unclonable mounts come in handy here.
 
 		step 1:
-		   lets say the root tree has just two directories with
+		   let's say the root tree has just two directories with
 		   one vfsmount.
 				    root
 				   /    \

Re: [PATCH v2] documentation: split and build smount.c

[Karel Zak]

On Mon, Aug 18, 2008 at 06:14:09PM -0700, Randy Dunlap wrote:
> On Mon, 18 Aug 2008 01:04:31 -0400 Christoph Hellwig wrote:
> 
> > Just remove it, and modern /bin/mount handles shared subtrees just fine
> 
> Miklos... ?
> 
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> From: Randy Dunlap <randy.dunlap@oracle.com>
> 
> mount(8) handles shared subtrees just fine, so remove the smount
> program from Documentation/filesystems/sharedsubtree.txt.
[...]
> +	Note: mount(8) command now supports the --make-shared flag,

 Right, ACK ;-)

>  	#mount --bind /mnt /tmp

 BTW, people usually use a space between prompt and command, so:

   # mount --bind /mnt /tmp


    Karel


-- 
 Karel Zak  <kzak@redhat.com>

Re: [PATCH v2] documentation: split and build smount.c

[Randy Dunlap]

On Wed, 20 Aug 2008 00:56:25 +0200 Karel Zak wrote:

> On Mon, Aug 18, 2008 at 06:14:09PM -0700, Randy Dunlap wrote:
> > On Mon, 18 Aug 2008 01:04:31 -0400 Christoph Hellwig wrote:
> > 
> > > Just remove it, and modern /bin/mount handles shared subtrees just fine
> > 
> > Miklos... ?
> > 
> > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> > From: Randy Dunlap <randy.dunlap@oracle.com>
> > 
> > mount(8) handles shared subtrees just fine, so remove the smount
> > program from Documentation/filesystems/sharedsubtree.txt.
> [...]
> > +	Note: mount(8) command now supports the --make-shared flag,
> 
>  Right, ACK ;-)
> 
> >  	#mount --bind /mnt /tmp
> 
>  BTW, people usually use a space between prompt and command, so:
> 
>    # mount --bind /mnt /tmp

Done for upcoming patch.  Thanks.

---
~Randy

Re: [PATCH v2] documentation: split and build smount.c

[Miklos Szeredi]

On Mon, 18 Aug 2008, Randy Dunlap wrote:
> On Mon, 18 Aug 2008 01:04:31 -0400 Christoph Hellwig wrote:
> 
> > Just remove it, and modern /bin/mount handles shared subtrees just fine
> 
> Miklos... ?

Yes, ACK from me too.  Thanks Randy!

Miklos

> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> From: Randy Dunlap <randy.dunlap@oracle.com>
> 
> mount(8) handles shared subtrees just fine, so remove the smount
> program from Documentation/filesystems/sharedsubtree.txt.
> 
> Fix annoying "Lets" -> "Let's".
> 
> Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
> cc: Miklos Szeredi <miklos@szeredi.hu>
> ---
>  Documentation/filesystems/sharedsubtree.txt |  192 +++-------------------------
>  1 file changed, 25 insertions(+), 167 deletions(-)
> 
> --- lin2627-rc3g4-kerndoc.orig/Documentation/filesystems/sharedsubtree.txt
> +++ lin2627-rc3g4-kerndoc/Documentation/filesystems/sharedsubtree.txt
> @@ -41,12 +41,11 @@ replicas continue to be exactly same.
>  
>  	Here is an example:
>  
> -	Lets say /mnt has a mount that is shared.
> +	Let's say /mnt has a mount that is shared.
>  	mount --make-shared /mnt
>  
> -	note: mount command does not yet support the --make-shared flag.
> -	I have included a small C program which does the same by executing
> -	'smount /mnt shared'
> +	Note: mount(8) command now supports the --make-shared flag,
> +	so the sample 'smount' program is no longer needed.
>  
>  	#mount --bind /mnt /tmp
>  	The above command replicates the mount at /mnt to the mountpoint /tmp
> @@ -58,7 +57,7 @@ replicas continue to be exactly same.
>  	#ls /tmp
>  	a b c
>  
> -	Now lets say we mount a device at /tmp/a
> +	Now let's say we mount a device at /tmp/a
>  	#mount /dev/sd0  /tmp/a
>  
>  	#ls /tmp/a
> @@ -80,20 +79,19 @@ replicas continue to be exactly same.
>  
>  	Here is an example:
>  
> -	Lets say /mnt has a mount which is shared.
> +	Let's say /mnt has a mount which is shared.
>  	#mount --make-shared /mnt
>  
> -	Lets bind mount /mnt to /tmp
> +	Let's bind mount /mnt to /tmp
>  	#mount --bind /mnt /tmp
>  
>  	the new mount at /tmp becomes a shared mount and it is a replica of
>  	the mount at /mnt.
>  
> -	Now lets make the mount at /tmp; a slave of /mnt
> +	Now let's make the mount at /tmp; a slave of /mnt
>  	#mount --make-slave /tmp
> -	[or smount /tmp slave]
>  
> -	lets mount /dev/sd0 on /mnt/a
> +	let's mount /dev/sd0 on /mnt/a
>  	#mount /dev/sd0 /mnt/a
>  
>  	#ls /mnt/a
> @@ -104,7 +102,7 @@ replicas continue to be exactly same.
>  
>  	Note the mount event has propagated to the mount at /tmp
>  
> -	However lets see what happens if we mount something on the mount at /tmp
> +	However let's see what happens if we mount something on the mount at /tmp
>  
>  	#mount /dev/sd1 /tmp/b
>  
> @@ -124,12 +122,11 @@ replicas continue to be exactly same.
>  
>  2d) A unbindable mount is a unbindable private mount
>  
> -	lets say we have a mount at /mnt and we make is unbindable
> +	let's say we have a mount at /mnt and we make is unbindable
>  
>  	#mount --make-unbindable /mnt
> -	 [ smount /mnt  unbindable ]
>  
> -	 Lets try to bind mount this mount somewhere else.
> +	 Let's try to bind mount this mount somewhere else.
>  	 # mount --bind /mnt /tmp
>  	 mount: wrong fs type, bad option, bad superblock on /mnt,
>  	        or too many mounted file systems
> @@ -139,147 +136,8 @@ replicas continue to be exactly same.
>  
>  3) smount command
>  
> -	Currently the mount command is not aware of shared subtree features.
> -	Work is in progress to add the support in mount ( util-linux package ).
> -	Till then use the following program.
> -
> -	------------------------------------------------------------------------
> -	//
> -	//this code was developed my Miklos Szeredi <miklos@szeredi.hu>
> -	//and modified by Ram Pai <linuxram@us.ibm.com>
> -	// sample usage:
> -	//              smount /tmp shared
> -	//
> -	#include <stdio.h>
> -	#include <stdlib.h>
> -	#include <unistd.h>
> -	#include <string.h>
> -	#include <sys/mount.h>
> -	#include <sys/fsuid.h>
> -
> -	#ifndef MS_REC
> -	#define MS_REC		0x4000	/* 16384: Recursive loopback */
> -	#endif
> -
> -	#ifndef MS_SHARED
> -	#define MS_SHARED		1<<20	/* Shared */
> -	#endif
> -
> -	#ifndef MS_PRIVATE
> -	#define MS_PRIVATE		1<<18	/* Private */
> -	#endif
> -
> -	#ifndef MS_SLAVE
> -	#define MS_SLAVE		1<<19	/* Slave */
> -	#endif
> -
> -	#ifndef MS_UNBINDABLE
> -	#define MS_UNBINDABLE		1<<17	/* Unbindable */
> -	#endif
> -
> -	int main(int argc, char *argv[])
> -	{
> -		int type;
> -		if(argc != 3) {
> -			fprintf(stderr, "usage: %s dir "
> -			"<rshared|rslave|rprivate|runbindable|shared|slave"
> -			"|private|unbindable>\n" , argv[0]);
> -			return 1;
> -		}
> -
> -		fprintf(stdout, "%s %s %s\n", argv[0], argv[1], argv[2]);
> -
> -		if (strcmp(argv[2],"rshared")==0)
> -			type=(MS_SHARED|MS_REC);
> -		else if (strcmp(argv[2],"rslave")==0)
> -			type=(MS_SLAVE|MS_REC);
> -		else if (strcmp(argv[2],"rprivate")==0)
> -			type=(MS_PRIVATE|MS_REC);
> -		else if (strcmp(argv[2],"runbindable")==0)
> -			type=(MS_UNBINDABLE|MS_REC);
> -		else if (strcmp(argv[2],"shared")==0)
> -			type=MS_SHARED;
> -		else if (strcmp(argv[2],"slave")==0)
> -			type=MS_SLAVE;
> -		else if (strcmp(argv[2],"private")==0)
> -			type=MS_PRIVATE;
> -		else if (strcmp(argv[2],"unbindable")==0)
> -			type=MS_UNBINDABLE;
> -		else {
> -			fprintf(stderr, "invalid operation: %s\n", argv[2]);
> -			return 1;
> -		}
> -		setfsuid(getuid());
> -
> -		if(mount("", argv[1], "dontcare", type, "") == -1) {
> -			perror("mount");
> -			return 1;
> -		}
> -		return 0;
> -	}
> -	-----------------------------------------------------------------------
> -
> -	Copy the above code snippet into smount.c
> -	gcc -o smount smount.c
> -
> -
> -	(i) To mark all the mounts under /mnt as shared execute the following
> -	command:
> -
> -	 	smount /mnt rshared
> -		the corresponding syntax planned for mount command is
> -		mount --make-rshared /mnt
> -
> -	    just to mark a mount /mnt as shared, execute the following
> -	    command:
> -	 	smount /mnt shared
> -		the corresponding syntax planned for mount command is
> -		mount --make-shared /mnt
> -
> -	(ii) To mark all the shared mounts under /mnt as slave execute the
> -	following
> -
> -	     command:
> -		smount /mnt rslave
> -		the corresponding syntax planned for mount command is
> -		mount --make-rslave /mnt
> -
> -	    just to mark a mount /mnt as slave, execute the following
> -	    command:
> -	 	smount /mnt slave
> -		the corresponding syntax planned for mount command is
> -		mount --make-slave /mnt
> -
> -	(iii) To mark all the mounts under /mnt as private execute the
> -	following command:
> -
> -		smount /mnt rprivate
> -		the corresponding syntax planned for mount command is
> -		mount --make-rprivate /mnt
> -
> -	    just to mark a mount /mnt as private, execute the following
> -	    command:
> -	 	smount /mnt private
> -		the corresponding syntax planned for mount command is
> -		mount --make-private /mnt
> -
> -	      NOTE: by default all the mounts are created as private. But if
> -	      you want to change some shared/slave/unbindable  mount as
> -	      private at a later point in time, this command can help.
> -
> -	(iv) To mark all the mounts under /mnt as unbindable execute the
> -	following
> -
> -	     command:
> -		smount /mnt runbindable
> -		the corresponding syntax planned for mount command is
> -		mount --make-runbindable /mnt
> -
> -	    just to mark a mount /mnt as unbindable, execute the following
> -	    command:
> -	 	smount /mnt unbindable
> -		the corresponding syntax planned for mount command is
> -		mount --make-unbindable /mnt
> +	Modern mount(8) command is aware of shared subtree features,
> +	so use it instead of the 'smount' command. [source code removed]
>  
>  
>  4) Use cases
> @@ -558,7 +416,7 @@ replicas continue to be exactly same.
>  	then the subtree under the unbindable mount is pruned in the new
>  	location.
>  
> -	eg: lets say we have the following mount tree.
> +	eg: let's say we have the following mount tree.
>  
>  		A
>  	      /   \
> @@ -566,7 +424,7 @@ replicas continue to be exactly same.
>  	     / \ / \
>  	     D E F G
>  
> -	     Lets say all the mount except the mount C in the tree are
> +	     Let's say all the mount except the mount C in the tree are
>  	     of a type other than unbindable.
>  
>  	     If this tree is rbound to say Z
> @@ -683,13 +541,13 @@ replicas continue to be exactly same.
>  	'b' on mounts that receive propagation from mount 'B' and does not have
>  	sub-mounts within them are unmounted.
>  
> -	Example: Lets say 'B1', 'B2', 'B3' are shared mounts that propagate to
> +	Example: Let's say 'B1', 'B2', 'B3' are shared mounts that propagate to
>  	each other.
>  
> -	lets say 'A1', 'A2', 'A3' are first mounted at dentry 'b' on mount
> +	let's say 'A1', 'A2', 'A3' are first mounted at dentry 'b' on mount
>  	'B1', 'B2' and 'B3' respectively.
>  
> -	lets say 'C1', 'C2', 'C3' are next mounted at the same dentry 'b' on
> +	let's say 'C1', 'C2', 'C3' are next mounted at the same dentry 'b' on
>  	mount 'B1', 'B2' and 'B3' respectively.
>  
>  	if 'C1' is unmounted, all the mounts that are most-recently-mounted on
> @@ -710,7 +568,7 @@ replicas continue to be exactly same.
>  	A cloned namespace contains all the mounts as that of the parent
>  	namespace.
>  
> -	Lets say 'A' and 'B' are the corresponding mounts in the parent and the
> +	Let's say 'A' and 'B' are the corresponding mounts in the parent and the
>  	child namespace.
>  
>  	If 'A' is shared, then 'B' is also shared and 'A' and 'B' propagate to
> @@ -759,11 +617,11 @@ replicas continue to be exactly same.
>  		mount --make-slave /mnt
>  
>  		At this point we have the first mount at /tmp and
> -		its root dentry is 1. Lets call this mount 'A'
> +		its root dentry is 1. Let's call this mount 'A'
>  		And then we have a second mount at /tmp1 with root
> -		dentry 2. Lets call this mount 'B'
> +		dentry 2. Let's call this mount 'B'
>  		Next we have a third mount at /mnt with root dentry
> -		mnt. Lets call this mount 'C'
> +		mnt. Let's call this mount 'C'
>  
>  		'B' is the slave of 'A' and 'C' is a slave of 'B'
>  		A -> B -> C
> @@ -794,7 +652,7 @@ replicas continue to be exactly same.
>  
>  	Q3 Why is unbindable mount needed?
>  
> -		Lets say we want to replicate the mount tree at multiple
> +		Let's say we want to replicate the mount tree at multiple
>  		locations within the same subtree.
>  
>  		if one rbind mounts a tree within the same subtree 'n' times
> @@ -803,7 +661,7 @@ replicas continue to be exactly same.
>  		mounts. Here is a example.
>  
>  		step 1:
> -		   lets say the root tree has just two directories with
> +		   let's say the root tree has just two directories with
>  		   one vfsmount.
>  				    root
>  				   /    \
> @@ -875,7 +733,7 @@ replicas continue to be exactly same.
>  		Unclonable mounts come in handy here.
>  
>  		step 1:
> -		   lets say the root tree has just two directories with
> +		   let's say the root tree has just two directories with
>  		   one vfsmount.
>  				    root
>  				   /    \
>