From 07b20889e3052c7e77d6a6a54e7e83446eb1ba84 Mon Sep 17 00:00:00 2001 From: Ram Pai Date: Mon, 7 Nov 2005 17:19:07 -0500 Subject: [PATCH] beginning of the shared-subtree proper A private mount does not forward or receive propagation. This patch provides user the ability to convert any mount to private. Signed-off-by: Ram Pai Signed-off-by: Al Viro Signed-off-by: Linus Torvalds --- fs/Makefile | 2 +- fs/namespace.c | 24 ++++++++++++++++++++++++ fs/pnode.c | 17 +++++++++++++++++ fs/pnode.h | 14 ++++++++++++++ include/linux/fs.h | 1 + include/linux/mount.h | 10 +++++----- 6 files changed, 62 insertions(+), 6 deletions(-) create mode 100644 fs/pnode.c create mode 100644 fs/pnode.h diff --git a/fs/Makefile b/fs/Makefile index 1972da1..4c26557 100644 --- a/fs/Makefile +++ b/fs/Makefile @@ -10,7 +10,7 @@ obj-y := open.o read_write.o file_table.o buffer.o bio.o super.o \ ioctl.o readdir.o select.o fifo.o locks.o dcache.o inode.o \ attr.o bad_inode.o file.o filesystems.o namespace.o aio.o \ seq_file.o xattr.o libfs.o fs-writeback.o mpage.o direct-io.o \ - ioprio.o + ioprio.o pnode.o obj-$(CONFIG_INOTIFY) += inotify.o obj-$(CONFIG_EPOLL) += eventpoll.o diff --git a/fs/namespace.c b/fs/namespace.c index 4abee9a..3782923 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -24,6 +24,7 @@ #include #include #include +#include "pnode.h" extern int __init init_rootfs(void); @@ -663,6 +664,27 @@ out_unlock: } /* + * recursively change the type of the mountpoint. + */ +static int do_change_type(struct nameidata *nd, int flag) +{ + struct vfsmount *m, *mnt = nd->mnt; + int recurse = flag & MS_REC; + int type = flag & ~MS_REC; + + if (nd->dentry != nd->mnt->mnt_root) + return -EINVAL; + + down_write(&namespace_sem); + spin_lock(&vfsmount_lock); + for (m = mnt; m; m = (recurse ? next_mnt(m, mnt) : NULL)) + change_mnt_propagation(m, type); + spin_unlock(&vfsmount_lock); + up_write(&namespace_sem); + return 0; +} + +/* * do loopback mount. */ static int do_loopback(struct nameidata *nd, char *old_name, int recurse) @@ -1091,6 +1113,8 @@ long do_mount(char *dev_name, char *dir_name, char *type_page, data_page); else if (flags & MS_BIND) retval = do_loopback(&nd, dev_name, flags & MS_REC); + else if (flags & MS_PRIVATE) + retval = do_change_type(&nd, flags); else if (flags & MS_MOVE) retval = do_move_mount(&nd, dev_name); else diff --git a/fs/pnode.c b/fs/pnode.c new file mode 100644 index 0000000..aaa0dff --- /dev/null +++ b/fs/pnode.c @@ -0,0 +1,17 @@ +/* + * linux/fs/pnode.c + * + * (C) Copyright IBM Corporation 2005. + * Released under GPL v2. + * Author : Ram Pai (linuxram@us.ibm.com) + * + */ +#include +#include +#include +#include "pnode.h" + +void change_mnt_propagation(struct vfsmount *mnt, int type) +{ + mnt->mnt_flags &= ~MNT_PNODE_MASK; +} diff --git a/fs/pnode.h b/fs/pnode.h new file mode 100644 index 0000000..33549a3 --- /dev/null +++ b/fs/pnode.h @@ -0,0 +1,14 @@ +/* + * linux/fs/pnode.h + * + * (C) Copyright IBM Corporation 2005. + * Released under GPL v2. + * + */ +#ifndef _LINUX_PNODE_H +#define _LINUX_PNODE_H + +#include +#include +void change_mnt_propagation(struct vfsmount *, int); +#endif /* _LINUX_PNODE_H */ diff --git a/include/linux/fs.h b/include/linux/fs.h index 9a593ef..6c43108 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -104,6 +104,7 @@ extern int dir_notify_enable; #define MS_MOVE 8192 #define MS_REC 16384 #define MS_VERBOSE 32768 +#define MS_PRIVATE (1<<18) /* change to private */ #define MS_POSIXACL (1<<16) /* VFS does not apply the umask */ #define MS_ACTIVE (1<<30) #define MS_NOUSER (1<<31) diff --git a/include/linux/mount.h b/include/linux/mount.h index ffb0b50..8eadd3b 100644 --- a/include/linux/mount.h +++ b/include/linux/mount.h @@ -17,12 +17,12 @@ #include #include -#define MNT_NOSUID 1 -#define MNT_NODEV 2 -#define MNT_NOEXEC 4 +#define MNT_NOSUID 0x01 +#define MNT_NODEV 0x02 +#define MNT_NOEXEC 0x04 +#define MNT_PNODE_MASK 0x30 /* propogation flag mask */ -struct vfsmount -{ +struct vfsmount { struct list_head mnt_hash; struct vfsmount *mnt_parent; /* fs we are mounted on */ struct dentry *mnt_mountpoint; /* dentry of mountpoint */ -- cgit v1.1