introduce slave mounts

PATCH In review Al Viro 1 participant 1 message Nov 8, 2005 VFS

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Al Viro

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2005-11-08 02:01 UTC #0 lore raw

PATCH 15/18 introduce slave mounts

From: Ram Pai <[email protected]>
Date: 1131402048 -0500

A slave mount always has a master mount from which it receives mount/umount events. Unlike shared mount the event propagation does not flow from the slave mount to the master.

Signed-off-by Ram Pai ([email protected])

Signed-off-by Al Viro <[email protected]>

---

 fs/namespace.c        |    4 +++-
 fs/pnode.c            |   54 ++++++++++++++++++++++++++++++++++++++++++++++---
 fs/pnode.h            |    2 ++
 include/linux/fs.h    |    1 +
 include/linux/mount.h |    3 +++
 5 files changed, 60 insertions(+), 4 deletions(-)

f98429253bbedb8511dd1c0af294d95a4c5cbc5d

fs/namespace.c +3 -1

@@ -67,6 +67,8 @@ struct vfsmount *alloc_vfsmnt(const char
 		INIT_LIST_HEAD(&mnt->mnt_list);
 		INIT_LIST_HEAD(&mnt->mnt_expire);
 		INIT_LIST_HEAD(&mnt->mnt_share);
+		INIT_LIST_HEAD(&mnt->mnt_slave_list);
+		INIT_LIST_HEAD(&mnt->mnt_slave);
 		if (name) {
 			int size = strlen(name) + 1;
 			char *newname = kmalloc(size, GFP_KERNEL);

@@ -1243,7 +1245,7 @@ long do_mount(char *dev_name, char *dir_
 				    data_page);
 	else if (flags & MS_BIND)
 		retval = do_loopback(&nd, dev_name, flags & MS_REC);
-	else if (flags & (MS_SHARED | MS_PRIVATE))
+	else if (flags & (MS_SHARED | MS_PRIVATE | MS_SLAVE))
 		retval = do_change_type(&nd, flags);
 	else if (flags & MS_MOVE)
 		retval = do_move_mount(&nd, dev_name);

fs/pnode.c +51 -3

64 lines not on this page · raw message

fs/pnode.h +2 -0

@@ -12,10 +12,12 @@
 #include <linux/mount.h>
 
 #define IS_MNT_SHARED(mnt) (mnt->mnt_flags & MNT_SHARED)
+#define IS_MNT_SLAVE(mnt) (mnt->mnt_master)
 #define IS_MNT_NEW(mnt)  (!mnt->mnt_namespace)
 #define CLEAR_MNT_SHARED(mnt) (mnt->mnt_flags &= ~MNT_SHARED)
 
 #define CL_EXPIRE    		0x01
+#define CL_SLAVE     		0x02
 #define CL_COPY_ALL 		0x04
 #define CL_MAKE_SHARED 		0x08
 #define CL_PROPAGATION 		0x10

include/linux/fs.h +1 -0

@@ -105,6 +105,7 @@ extern int dir_notify_enable;
 #define MS_REC		16384
 #define MS_VERBOSE	32768
 #define MS_PRIVATE	(1<<18)	/* change to private */
+#define MS_SLAVE	(1<<19)	/* change to slave */
 #define MS_SHARED	(1<<20)	/* change to shared */
 #define MS_POSIXACL	(1<<16)	/* VFS does not apply the umask */
 #define MS_ACTIVE	(1<<30)

include/linux/mount.h +3 -0

@@ -38,6 +38,9 @@ struct vfsmount {
 	struct list_head mnt_list;
 	struct list_head mnt_expire;	/* link in fs-specific expiry list */
 	struct list_head mnt_share;	/* circular list of shared mounts */
+	struct list_head mnt_slave_list;/* list of slave mounts */
+	struct list_head mnt_slave;	/* slave list entry */
+	struct vfsmount *mnt_master;	/* slave is on master->mnt_slave_list */
 	struct namespace *mnt_namespace; /* containing namespace */
 	int mnt_pinned;
 };