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| author | Pavel Emelyanov <xemul@openvz.org> | 2007-10-18 23:40:02 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-10-19 11:53:38 -0700 |
| commit | 8bf9725c29f2589237dd696d06a204230add0ba3 (patch) | |
| tree | abe1a29924a592808250121435dcd12789336e8a | |
| parent | 2e4a707269a409950c3f315010c20f9719c594e2 (diff) | |
| download | lwn-8bf9725c29f2589237dd696d06a204230add0ba3.tar.gz lwn-8bf9725c29f2589237dd696d06a204230add0ba3.zip | |
pid namespaces: introduce MS_KERNMOUNT flag
This flag tells the .get_sb callback that this is a kern_mount() call so that
it can trust *data pointer to be valid in-kernel one. If this flag is passed
from the user process, it is cleared since the *data pointer is not a valid
kernel object.
Running a few steps forward - this will be needed for proc to create the
superblock and store a valid pid namespace on it during the namespace
creation. The reason, why the namespace cannot live without proc mount is
described in the appropriate patch.
Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Sukadev Bhattiprolu <sukadev@us.ibm.com>
Cc: Paul Menage <menage@google.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | fs/namespace.c | 2 | ||||
| -rw-r--r-- | fs/super.c | 6 | ||||
| -rw-r--r-- | include/linux/fs.h | 4 |
3 files changed, 7 insertions, 5 deletions
diff --git a/fs/namespace.c b/fs/namespace.c index 07daa7972591..860752998fb3 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -1411,7 +1411,7 @@ long do_mount(char *dev_name, char *dir_name, char *type_page, mnt_flags |= MNT_RELATIME; flags &= ~(MS_NOSUID | MS_NOEXEC | MS_NODEV | MS_ACTIVE | - MS_NOATIME | MS_NODIRATIME | MS_RELATIME); + MS_NOATIME | MS_NODIRATIME | MS_RELATIME| MS_KERNMOUNT); /* ... and get the mountpoint */ retval = path_lookup(dir_name, LOOKUP_FOLLOW, &nd); diff --git a/fs/super.c b/fs/super.c index feaae7eeaffd..d28fde7e1cfb 100644 --- a/fs/super.c +++ b/fs/super.c @@ -944,9 +944,9 @@ do_kern_mount(const char *fstype, int flags, const char *name, void *data) return mnt; } -struct vfsmount *kern_mount(struct file_system_type *type) +struct vfsmount *kern_mount_data(struct file_system_type *type, void *data) { - return vfs_kern_mount(type, 0, type->name, NULL); + return vfs_kern_mount(type, MS_KERNMOUNT, type->name, data); } -EXPORT_SYMBOL(kern_mount); +EXPORT_SYMBOL_GPL(kern_mount_data); diff --git a/include/linux/fs.h b/include/linux/fs.h index 3efff12049c6..1657e995f72c 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -123,6 +123,7 @@ extern int dir_notify_enable; #define MS_SLAVE (1<<19) /* change to slave */ #define MS_SHARED (1<<20) /* change to shared */ #define MS_RELATIME (1<<21) /* Update atime relative to mtime/ctime. */ +#define MS_KERNMOUNT (1<<22) /* this is a kern_mount call */ #define MS_ACTIVE (1<<30) #define MS_NOUSER (1<<31) @@ -1459,7 +1460,8 @@ void unnamed_dev_init(void); extern int register_filesystem(struct file_system_type *); extern int unregister_filesystem(struct file_system_type *); -extern struct vfsmount *kern_mount(struct file_system_type *); +extern struct vfsmount *kern_mount_data(struct file_system_type *, void *data); +#define kern_mount(type) kern_mount_data(type, NULL) extern int may_umount_tree(struct vfsmount *); extern int may_umount(struct vfsmount *); extern void umount_tree(struct vfsmount *, int, struct list_head *); |