How to query mount propagation state?

Serge E. Hallyn serue at us.ibm.com
Mon Apr 16 12:16:00 PDT 2007


Quoting Ram Pai (linuxram at us.ibm.com):
> On Mon, 2007-04-16 at 12:34 +0200, Miklos Szeredi wrote:
> > Currently one of the difficulties with mount propagations is that
> > there's no way to know the current state of the propagation tree.
> > 
> > Has anyone thought about how this info could be queried from
> > userspace?
> 
> I am attaching two patches that I had done way back in Oct 2006 
> with Al Viro. I had sent these patches to Al Viro. But I forgot to
> follow them up, I guess so did Al Viro.
> 
> The first patch disambiguates multiple mount-instances of the same
> filesystem (or part of the same filesystem), by introducing a new
> interface /proc/mounts_new. 
> 
> The second patch introduces a new proc interface that exposes all the
> propagation trees within a namespace.  It does not show propagated
> mounts residing in a different namespace (for privacy reasons). Maybe
> one could modify the patch a little, to allow it; if the user has
> root priviledges. 
> 
> RP
> 
> PS: Sorry these are attachments instead of inline patches. I am scared
> of inlining in evolution. If needed I can send inline patches through
> mutt.
> 
> > 
> > Thanks,
> > Miklos

> This patch disambiguates multiple mount-instances of the same
> filesystem (or part of the same filesystem), by introducing a new
> interface /proc/mounts_new. The interface has the following format.
> 
> ------------------------------------------------------------
> FSID  mntpt  root-dentry  fstype fs-options
> ------------------------------------------------------------
> 
> NOTE: root-dentry is the path to the dentry w.r.t to the root dentry of the
> same filesystem.
> 
> for example: lets say we attempt the following commands
> mount --bind /var /mnt
> mount --bind /mnt/tmp /tmp1
> 
> 'cat /proc/mounts' shows the following:
> /dev/root /mnt ext2 rw 0 0
> /dev/root /tmp1 ext2 rw 0 0
> 
> NOTE: The above mount entries, do not indicate that /tmp1 contains the same
> directory tree as /var/tmp.
> 
> But 'cat /proc/mounts_new' shows us the following:
> 0x6200 /mnt /var ext2 rw 0 0
> 0x6200 /tmp1 /var/tmp ext2 rw 0 0
> 
> The above entries clearly indicates that /var/tmp directory of the ext2
> filesystem with fsid=0x6200 is the directory tree that resides under /tmp1
> 
> Signed-off-by: Ram Pai <linuxram at us.ibm.com>
> 
> ---
>  fs/dcache.c              |   53 ++++++++++++++++++++++++++++++++
>  fs/namespace.c           |   35 ++++++++++++++++++---
>  fs/proc/base.c           |   32 +++++++++++++++++--
>  fs/proc/proc_misc.c      |    1 
>  fs/seq_file.c            |   77 ++++++++++++++++++++++++++++++++++-------------
>  include/linux/dcache.h   |    1 
>  include/linux/seq_file.h |    1 
>  7 files changed, 172 insertions(+), 28 deletions(-)
> 
> Index: linux-2.6.17.10/fs/proc/base.c
> ===================================================================
> --- linux-2.6.17.10.orig/fs/proc/base.c
> +++ linux-2.6.17.10/fs/proc/base.c
> @@ -104,6 +104,7 @@ enum pid_directory_inos {
>  	PROC_TGID_MAPS,
>  	PROC_TGID_NUMA_MAPS,
>  	PROC_TGID_MOUNTS,
> +	PROC_TGID_MOUNTS_NEW,
>  	PROC_TGID_MOUNTSTATS,
>  	PROC_TGID_WCHAN,
>  #ifdef CONFIG_MMU
> @@ -145,6 +146,7 @@ enum pid_directory_inos {
>  	PROC_TID_MAPS,
>  	PROC_TID_NUMA_MAPS,
>  	PROC_TID_MOUNTS,
> +	PROC_TID_MOUNTS_NEW,
>  	PROC_TID_MOUNTSTATS,
>  	PROC_TID_WCHAN,
>  #ifdef CONFIG_MMU
> @@ -203,6 +205,7 @@ static struct pid_entry tgid_base_stuff[
>  	E(PROC_TGID_ROOT,      "root",    S_IFLNK|S_IRWXUGO),
>  	E(PROC_TGID_EXE,       "exe",     S_IFLNK|S_IRWXUGO),
>  	E(PROC_TGID_MOUNTS,    "mounts",  S_IFREG|S_IRUGO),
> +	E(PROC_TGID_MOUNTS_NEW,"mounts_new",  S_IFREG|S_IRUGO),
>  	E(PROC_TGID_MOUNTSTATS, "mountstats", S_IFREG|S_IRUSR),
>  #ifdef CONFIG_MMU
>  	E(PROC_TGID_SMAPS,     "smaps",   S_IFREG|S_IRUGO),
> @@ -246,6 +249,7 @@ static struct pid_entry tid_base_stuff[]
>  	E(PROC_TID_ROOT,       "root",    S_IFLNK|S_IRWXUGO),
>  	E(PROC_TID_EXE,        "exe",     S_IFLNK|S_IRWXUGO),
>  	E(PROC_TID_MOUNTS,     "mounts",  S_IFREG|S_IRUGO),
> +	E(PROC_TID_MOUNTS_NEW, "mounts_new",  S_IFREG|S_IRUGO),
>  #ifdef CONFIG_MMU
>  	E(PROC_TID_SMAPS,      "smaps",   S_IFREG|S_IRUGO),
>  #endif
> @@ -692,13 +696,13 @@ static struct file_operations proc_smaps
>  };
>  #endif
> 
> -extern struct seq_operations mounts_op;
>  struct proc_mounts {
>  	struct seq_file m;
>  	int event;
>  };
> 
> -static int mounts_open(struct inode *inode, struct file *file)
> +static int __mounts_open(struct inode *inode, struct file *file,
> +			struct seq_operations *mounts_op)
>  {
>  	struct task_struct *task = proc_task(inode);
>  	struct namespace *namespace;
> @@ -716,7 +720,7 @@ static int mounts_open(struct inode *ino
>  		p = kmalloc(sizeof(struct proc_mounts), GFP_KERNEL);
>  		if (p) {
>  			file->private_data = &p->m;
> -			ret = seq_open(file, &mounts_op);
> +			ret = seq_open(file, mounts_op);
>  			if (!ret) {
>  				p->m.private = namespace;
>  				p->event = namespace->event;
> @@ -729,6 +733,16 @@ static int mounts_open(struct inode *ino
>  	return ret;
>  }
> 
> +extern struct seq_operations mounts_op, mounts_new_op;
> +static int mounts_open(struct inode *inode, struct file *file)
> +{
> +	return (__mounts_open(inode, file, &mounts_op));
> +}
> +static int mounts_new_open(struct inode *inode, struct file *file)
> +{
> +	return __mounts_open(inode, file, &mounts_new_op);
> +}
> +
>  static int mounts_release(struct inode *inode, struct file *file)
>  {
>  	struct seq_file *m = file->private_data;
> @@ -763,6 +777,14 @@ static struct file_operations proc_mount
>  	.poll		= mounts_poll,
>  };
> 
> +static struct file_operations proc_mounts_new_operations = {
> +	.open		= mounts_new_open,
> +	.read		= seq_read,
> +	.llseek		= seq_lseek,
> +	.release	= mounts_release,
> +	.poll		= mounts_poll,
> +};
> +
>  extern struct seq_operations mountstats_op;
>  static int mountstats_open(struct inode *inode, struct file *file)
>  {
> @@ -1799,6 +1821,10 @@ static struct dentry *proc_pident_lookup
>  		case PROC_TGID_MOUNTS:
>  			inode->i_fop = &proc_mounts_operations;
>  			break;
> +		case PROC_TID_MOUNTS_NEW:
> +		case PROC_TGID_MOUNTS_NEW:
> +			inode->i_fop = &proc_mounts_new_operations;
> +			break;
>  #ifdef CONFIG_MMU
>  		case PROC_TID_SMAPS:
>  		case PROC_TGID_SMAPS:
> Index: linux-2.6.17.10/fs/dcache.c
> ===================================================================
> --- linux-2.6.17.10.orig/fs/dcache.c
> +++ linux-2.6.17.10/fs/dcache.c
> @@ -1477,6 +1477,59 @@ char * d_path(struct dentry *dentry, str
>  	return res;
>  }
> 
> +static inline int prepend(char **buffer, int *buflen, const char *str,
> +					int namelen)
> +{
> +	if ((*buflen -= namelen) < 0)
> +		return 1;
> +	*buffer -= namelen;
> +	memcpy(*buffer, str, namelen);
> +	return 0;
> +}
> +
> +/*
> + * write full pathname into buffer and return start of pathname.
> + * If @vfsmnt is not specified return the path relative to the
> + * its filesystem's root.
> + */
> +char * dentry_path(struct dentry *dentry, char *buf, int buflen)
> +{
> +	char * end = buf+buflen;
> +	char * retval;
> +
> +	spin_lock(&dcache_lock);
> +	prepend(&end, &buflen, "\0", 1);
> +	if (!IS_ROOT(dentry) && d_unhashed(dentry)) {
> +		if (prepend(&end, &buflen, "//deleted", 10))
> +			goto Elong;
> +	}
> +	/* Get '/' right */
> +	retval = end-1;
> +	*retval = '/';
> +
> +	for (;;) {
> +		struct dentry * parent;
> +		if (IS_ROOT(dentry))
> +			break;
> +
> +		parent = dentry->d_parent;
> +		prefetch(parent);
> +
> +		if (prepend(&end, &buflen, dentry->d_name.name,
> +				dentry->d_name.len) ||
> +	            prepend(&end, &buflen, "/", 1))
> +			goto Elong;
> +
> +		retval = end;
> +		dentry = parent;
> +	}
> +	spin_unlock(&dcache_lock);
> +	return retval;
> +Elong:
> +	spin_unlock(&dcache_lock);
> +	return ERR_PTR(-ENAMETOOLONG);
> +}
> +
>  /*
>   * NOTE! The user-level library version returns a
>   * character pointer. The kernel system call just
> Index: linux-2.6.17.10/fs/seq_file.c
> ===================================================================
> --- linux-2.6.17.10.orig/fs/seq_file.c
> +++ linux-2.6.17.10/fs/seq_file.c
> @@ -338,38 +338,75 @@ int seq_printf(struct seq_file *m, const
>  }
>  EXPORT_SYMBOL(seq_printf);
> 
> -int seq_path(struct seq_file *m,
> -	     struct vfsmount *mnt, struct dentry *dentry,
> +static inline char *mangle_path(char *s, char *p, char *esc)
> +{
> +	while (s <= p) {
> +		char c = *p++;
> +		if (!c) {
> +			return s;
> +		} else if (!strchr(esc, c)) {
> +			*s++ = c;
> +		} else if (s + 4 > p) {
> +			break;
> +		} else {
> +			*s++ = '\\';
> +			*s++ = '0' + ((c & 0300) >> 6);
> +			*s++ = '0' + ((c & 070) >> 3);
> +			*s++ = '0' + (c & 07);
> +		}
> +	}
> +	return NULL;
> +}
> +
> +/*
> + * return the absolute path of 'dentry' residing in mount 'mnt'.
> + */
> +int seq_path(struct seq_file *m, struct vfsmount *mnt, struct dentry *dentry,
>  	     char *esc)
>  {
> +	char *p = NULL;
>  	if (m->count < m->size) {
>  		char *s = m->buf + m->count;
> -		char *p = d_path(dentry, mnt, s, m->size - m->count);
> +		p = d_path(dentry, mnt, s, m->size - m->count);
>  		if (!IS_ERR(p)) {
> -			while (s <= p) {
> -				char c = *p++;
> -				if (!c) {
> -					p = m->buf + m->count;
> -					m->count = s - m->buf;
> -					return s - p;
> -				} else if (!strchr(esc, c)) {
> -					*s++ = c;
> -				} else if (s + 4 > p) {
> -					break;
> -				} else {
> -					*s++ = '\\';
> -					*s++ = '0' + ((c & 0300) >> 6);
> -					*s++ = '0' + ((c & 070) >> 3);
> -					*s++ = '0' + (c & 07);
> -				}
> +			s = mangle_path(s, p, esc);
> +			if (s) {
> +				p = m->buf + m->count;
> +				m->count = s - m->buf;
> +				return s - p;
>  			}
>  		}
>  	}
>  	m->count = m->size;
> -	return -1;
> +	return p == ERR_PTR(-ENAMETOOLONG) ? 0 : -1;
>  }
> +
>  EXPORT_SYMBOL(seq_path);
> 
> +/*
> + * returns the path of the 'dentry' from the root of its filesystem.
> + */
> +int seq_dentry(struct seq_file *m, struct dentry *dentry, char *esc)
> +{
> +	char *p = NULL;
> +	if (m->count < m->size) {
> +		char *s = m->buf + m->count;
> +		p = dentry_path(dentry, s, m->size - m->count);
> +		if (!IS_ERR(p)) {
> +			s = mangle_path(s, p, esc);
> +			if (s) {
> +				p = m->buf + m->count;
> +				m->count = s - m->buf;
> +				return s - p;
> +			}
> +		}
> +	}
> +	m->count = m->size;
> +	return p == ERR_PTR(-ENAMETOOLONG) ? 0 : -1;
> +}
> +
> +EXPORT_SYMBOL(seq_dentry);
> +
>  static void *single_start(struct seq_file *p, loff_t *pos)
>  {
>  	return NULL + (*pos == 0);
> Index: linux-2.6.17.10/fs/proc/proc_misc.c
> ===================================================================
> --- linux-2.6.17.10.orig/fs/proc/proc_misc.c
> +++ linux-2.6.17.10/fs/proc/proc_misc.c
> @@ -675,6 +675,7 @@ void __init proc_misc_init(void)
>  		create_proc_read_entry(p->name, 0, NULL, p->read_proc, NULL);
> 
>  	proc_symlink("mounts", NULL, "self/mounts");
> +	proc_symlink("mounts_new", NULL, "self/mounts_new");
> 
>  	/* And now for trickier ones */
>  	entry = create_proc_entry("kmsg", S_IRUSR, &proc_root);
> Index: linux-2.6.17.10/fs/namespace.c
> ===================================================================
> --- linux-2.6.17.10.orig/fs/namespace.c
> +++ linux-2.6.17.10/fs/namespace.c
> @@ -349,7 +349,7 @@ static inline void mangle(struct seq_fil
>  	seq_escape(m, s, " \t\n\\");
>  }
> 
> -static int show_vfsmnt(struct seq_file *m, void *v)
> +static int show_options(struct seq_file *m, void *v)
>  {
>  	struct vfsmount *mnt = v;
>  	int err = 0;
> @@ -372,10 +372,6 @@ static int show_vfsmnt(struct seq_file *
>  	};
>  	struct proc_fs_info *fs_infop;
> 
> -	mangle(m, mnt->mnt_devname ? mnt->mnt_devname : "none");
> -	seq_putc(m, ' ');
> -	seq_path(m, mnt, mnt->mnt_root, " \t\n\\");
> -	seq_putc(m, ' ');
>  	mangle(m, mnt->mnt_sb->s_type->name);
>  	seq_puts(m, mnt->mnt_sb->s_flags & MS_RDONLY ? " ro" : " rw");
>  	for (fs_infop = fs_info; fs_infop->flag; fs_infop++) {
> @@ -392,6 +388,28 @@ static int show_vfsmnt(struct seq_file *
>  	return err;
>  }
> 
> +static int show_vfsmnt(struct seq_file *m, void *v)
> +{
> +	struct vfsmount *mnt = v;
> +	mangle(m, mnt->mnt_devname ? mnt->mnt_devname : "none");
> +	seq_putc(m, ' ');
> +	seq_path(m, mnt, mnt->mnt_root, " \t\n\\");
> +	seq_putc(m, ' ');
> +	return show_options(m, v);
> +}
> +
> +static int show_vfsmnt_new(struct seq_file *m, void *v)
> +{
> +	struct vfsmount *mnt = v;
> +	seq_printf(m, "0x%x", new_encode_dev(mnt->mnt_sb->s_dev));
> +	seq_putc(m, ' ');
> +	seq_path(m, mnt, mnt->mnt_root, " \t\n\\");
> +	seq_putc(m, ' ');
> +	seq_dentry(m, mnt->mnt_root, " \t\n\\");
> +	seq_putc(m, ' ');
> +	return show_options(m, v);
> +}
> +
>  struct seq_operations mounts_op = {
>  	.start	= m_start,
>  	.next	= m_next,
> @@ -399,6 +417,13 @@ struct seq_operations mounts_op = {
>  	.show	= show_vfsmnt
>  };
> 
> +struct seq_operations mounts_new_op = {
> +	.start	= m_start,
> +	.next	= m_next,
> +	.stop	= m_stop,
> +	.show	= show_vfsmnt_new
> +};
> +
>  static int show_vfsstat(struct seq_file *m, void *v)
>  {
>  	struct vfsmount *mnt = v;
> Index: linux-2.6.17.10/include/linux/dcache.h
> ===================================================================
> --- linux-2.6.17.10.orig/include/linux/dcache.h
> +++ linux-2.6.17.10/include/linux/dcache.h
> @@ -281,6 +281,7 @@ extern struct dentry * d_hash_and_lookup
>  extern int d_validate(struct dentry *, struct dentry *);
> 
>  extern char * d_path(struct dentry *, struct vfsmount *, char *, int);
> +extern char * dentry_path(struct dentry *, char *, int);
>    
>  /* Allocation counts.. */
> 
> Index: linux-2.6.17.10/include/linux/seq_file.h
> ===================================================================
> --- linux-2.6.17.10.orig/include/linux/seq_file.h
> +++ linux-2.6.17.10/include/linux/seq_file.h
> @@ -43,6 +43,7 @@ int seq_printf(struct seq_file *, const 
>  	__attribute__ ((format (printf,2,3)));
> 
>  int seq_path(struct seq_file *, struct vfsmount *, struct dentry *, char *);
> +int seq_dentry(struct seq_file *, struct dentry *, char *);
> 
>  int single_open(struct file *, int (*)(struct seq_file *, void *), void *);
>  int single_release(struct inode *, struct file *);

> This patch introduces a new proc interface that exposes all the propagation 
> trees within the namespace.
> 
> It walks through each off the mounts in the namespace, and prints the following information.
> 
> mount-id: a unique mount identifier
> dev-id : the unique device used to identify the device containing the filesystem
> path-from-root: mount point of the mount from /
> path-from-root-of-its-sb: path from its own root dentry.
> propagation-flag: SHARED, SLAVE, UNBINDABLE, PRIVATE
> peer-mount-id: the mount-id of its peer mount (if this mount is shared)
> master-mount-id: the mount-id of its master mount (if this mount is slave)
> 
> Using the above information one could easily write a script that can
> draw all the propagation trees in the namespace.
> 
> 
> Example:
> Here is a sample output of cat /proc/$$/mounts_propagation
> 
> 0xa917800 0x1 / / PRIVATE
> 0xa917200 0x6200 / / PRIVATE
> 0xa917180 0x3 /proc / PRIVATE
> 0xa917f80 0xa /dev/pts / PRIVATE
> 0xa917100 0x6210 /mnt / SHARED peer:0xa917100
> 0xa917f00 0x6210 /tmp /1 SLAVE master:0xa917100
> 0xa917900 0x6220 /mnt/2 / SHARED peer:0xa917900
> 
> line 5 indicates that the mount with id 0xa917100 is mounted at /mnt is shared
> and it is the only mount in its peer group.
> 
> line 6 indicates that the mount with id 0xa917f00 is mounted at /tmp, its 
> root is the dentry 1 present under its root directory. This mount is a
> slave mount and its master is the mount with id 0xa917100.
> 
> line 7 indicates that the mount with id 0xa917900 is mounted at /mnt/2, its 
> root is the dentry / of its filesystem. This mount is a
> shared and it is the only mount in its peer group.
> 
> one could write a script which runs through these lines and draws 4
> individual satellite mounts and two propagation trees, the first propagation
> tree has a shared mount and a slave mount.  and the second propagation tree has
> just one shared mount.
> 
> 	
> Signed-off-by: Ram Pai <linuxram at us.ibm.com>
> ---
>  fs/namespace.c |   42 ++++++++++++++++++++++++++++++++++++++++++
>  fs/pnode.c     |    6 ------
>  fs/pnode.h     |    6 ++++++
>  fs/proc/base.c |   22 +++++++++++++++++++++-
>  4 files changed, 69 insertions(+), 7 deletions(-)
> 
> Index: linux-2.6.17.10/fs/namespace.c
> ===================================================================
> --- linux-2.6.17.10.orig/fs/namespace.c
> +++ linux-2.6.17.10/fs/namespace.c
> @@ -410,6 +410,41 @@ static int show_vfsmnt_new(struct seq_fi
>  	return show_options(m, v);
>  }
> 
> +static int show_vfsmnt_propagation(struct seq_file *m, void *v)
> +{
> +	struct vfsmount *mnt = v;
> +	seq_printf(m, "0x%x", (int)mnt);
> +	seq_putc(m, ' ');
> +	seq_printf(m, "0x%x", new_encode_dev(mnt->mnt_sb->s_dev));
> +	seq_putc(m, ' ');
> +	seq_path(m, mnt, mnt->mnt_root, " \t\n\\");
> +	seq_putc(m, ' ');
> +	seq_dentry(m, mnt->mnt_root, " \t\n\\");
> +	seq_putc(m, ' ');
> +
> +	if (IS_MNT_SHARED(mnt)) {
> +		seq_printf(m, "%s ", "SHARED");
> +		if (IS_MNT_SLAVE(mnt)) {
> +			seq_printf(m, "%s ", "SLAVE");
> +		}
> +	} else if (IS_MNT_SLAVE(mnt)) {
> +		seq_printf(m, "%s ", "SLAVE");
> +	} else if (IS_MNT_UNBINDABLE(mnt)) {
> +		seq_printf(m, "%s ", "UNBINDABLE");
> +	} else {
> +		seq_printf(m, "%s ", "PRIVATE");
> +	}
> +
> +	if (IS_MNT_SHARED(mnt)) {
> +		seq_printf(m, "peer:0x%x ", (int)next_peer(mnt));

Ok, so if the sequence of events was

	mount --make-shared /mnt
	(some user logs in and gets a cloned namespace, so his /mnt
	becomes the next peer of /mnt)
	mount --bind /mnt /tmp
	(some other user logs in and gets cloned namespace...)

or some such sequence of events, we could lose all information
about /mnt and /tmp being peers, right?  Should a new
next_peer_in_same_namespace(mnt) be used rather than next_peer()?

Somewhat similarly,

> +	}
> +	if (IS_MNT_SLAVE(mnt)) {
> +		seq_printf(m, "master:0x%x ", (int)mnt->mnt_master);

Should we for privacy reasons not print out the address mnt->mnt_master
is in a different namespace (perhaps if !CAP_SYS_ADMIN)?

Otherwise I like this.

thanks,
-serge

> +	}
> +	seq_puts(m, "\n");
> +	return 0;
> +}
> +
>  struct seq_operations mounts_op = {
>  	.start	= m_start,
>  	.next	= m_next,
> @@ -424,6 +459,13 @@ struct seq_operations mounts_new_op = {
>  	.show	= show_vfsmnt_new
>  };
> 
> +struct seq_operations mounts_propagation_op = {
> +	.start	= m_start,
> +	.next	= m_next,
> +	.stop	= m_stop,
> +	.show	= show_vfsmnt_propagation
> +};
> +
>  static int show_vfsstat(struct seq_file *m, void *v)
>  {
>  	struct vfsmount *mnt = v;
> Index: linux-2.6.17.10/fs/proc/base.c
> ===================================================================
> --- linux-2.6.17.10.orig/fs/proc/base.c
> +++ linux-2.6.17.10/fs/proc/base.c
> @@ -105,6 +105,7 @@ enum pid_directory_inos {
>  	PROC_TGID_NUMA_MAPS,
>  	PROC_TGID_MOUNTS,
>  	PROC_TGID_MOUNTS_NEW,
> +	PROC_TGID_MOUNTS_PROPAGATION,
>  	PROC_TGID_MOUNTSTATS,
>  	PROC_TGID_WCHAN,
>  #ifdef CONFIG_MMU
> @@ -146,6 +147,7 @@ enum pid_directory_inos {
>  	PROC_TID_MAPS,
>  	PROC_TID_NUMA_MAPS,
>  	PROC_TID_MOUNTS,
> +	PROC_TID_MOUNTS_PROPAGATION,
>  	PROC_TID_MOUNTS_NEW,
>  	PROC_TID_MOUNTSTATS,
>  	PROC_TID_WCHAN,
> @@ -206,6 +208,7 @@ static struct pid_entry tgid_base_stuff[
>  	E(PROC_TGID_EXE,       "exe",     S_IFLNK|S_IRWXUGO),
>  	E(PROC_TGID_MOUNTS,    "mounts",  S_IFREG|S_IRUGO),
>  	E(PROC_TGID_MOUNTS_NEW,"mounts_new",  S_IFREG|S_IRUGO),
> +	E(PROC_TGID_MOUNTS_PROPAGATION,"mounts_propagation",  S_IFREG|S_IRUGO),
>  	E(PROC_TGID_MOUNTSTATS, "mountstats", S_IFREG|S_IRUSR),
>  #ifdef CONFIG_MMU
>  	E(PROC_TGID_SMAPS,     "smaps",   S_IFREG|S_IRUGO),
> @@ -250,6 +253,7 @@ static struct pid_entry tid_base_stuff[]
>  	E(PROC_TID_EXE,        "exe",     S_IFLNK|S_IRWXUGO),
>  	E(PROC_TID_MOUNTS,     "mounts",  S_IFREG|S_IRUGO),
>  	E(PROC_TID_MOUNTS_NEW, "mounts_new",  S_IFREG|S_IRUGO),
> +	E(PROC_TID_MOUNTS_PROPAGATION,"mounts_propagation",  S_IFREG|S_IRUGO),
>  #ifdef CONFIG_MMU
>  	E(PROC_TID_SMAPS,      "smaps",   S_IFREG|S_IRUGO),
>  #endif
> @@ -733,7 +737,7 @@ static int __mounts_open(struct inode *i
>  	return ret;
>  }
> 
> -extern struct seq_operations mounts_op, mounts_new_op;
> +extern struct seq_operations mounts_op, mounts_new_op, mounts_propagation_op;
>  static int mounts_open(struct inode *inode, struct file *file)
>  {
>  	return (__mounts_open(inode, file, &mounts_op));
> @@ -742,6 +746,10 @@ static int mounts_new_open(struct inode 
>  {
>  	return __mounts_open(inode, file, &mounts_new_op);
>  }
> +static int mounts_propagation_open(struct inode *inode, struct file *file)
> +{
> +	return __mounts_open(inode, file, &mounts_propagation_op);
> +}
> 
>  static int mounts_release(struct inode *inode, struct file *file)
>  {
> @@ -785,6 +793,14 @@ static struct file_operations proc_mount
>  	.poll		= mounts_poll,
>  };
> 
> +static struct file_operations proc_propagation_operations = {
> +	.open		= mounts_propagation_open,
> +	.read		= seq_read,
> +	.llseek		= seq_lseek,
> +	.release	= mounts_release,
> +	.poll		= mounts_poll,
> +};
> +
>  extern struct seq_operations mountstats_op;
>  static int mountstats_open(struct inode *inode, struct file *file)
>  {
> @@ -1825,6 +1841,10 @@ static struct dentry *proc_pident_lookup
>  		case PROC_TGID_MOUNTS_NEW:
>  			inode->i_fop = &proc_mounts_new_operations;
>  			break;
> +		case PROC_TID_MOUNTS_PROPAGATION:
> +		case PROC_TGID_MOUNTS_PROPAGATION:
> +			inode->i_fop = &proc_propagation_operations;
> +			break;
>  #ifdef CONFIG_MMU
>  		case PROC_TID_SMAPS:
>  		case PROC_TGID_SMAPS:
> Index: linux-2.6.17.10/fs/pnode.c
> ===================================================================
> --- linux-2.6.17.10.orig/fs/pnode.c
> +++ linux-2.6.17.10/fs/pnode.c
> @@ -11,12 +11,6 @@
>  #include <linux/fs.h>
>  #include "pnode.h"
> 
> -/* return the next shared peer mount of @p */
> -static inline struct vfsmount *next_peer(struct vfsmount *p)
> -{
> -	return list_entry(p->mnt_share.next, struct vfsmount, mnt_share);
> -}
> -
>  static inline struct vfsmount *first_slave(struct vfsmount *p)
>  {
>  	return list_entry(p->mnt_slave_list.next, struct vfsmount, mnt_slave);
> Index: linux-2.6.17.10/fs/pnode.h
> ===================================================================
> --- linux-2.6.17.10.orig/fs/pnode.h
> +++ linux-2.6.17.10/fs/pnode.h
> @@ -29,6 +29,12 @@ static inline void set_mnt_shared(struct
>  	mnt->mnt_flags |= MNT_SHARED;
>  }
> 
> +/* return the next shared peer mount of @p */
> +static inline struct vfsmount *next_peer(struct vfsmount *p)
> +{
> +	return list_entry(p->mnt_share.next, struct vfsmount, mnt_share);
> +}
> +
>  void change_mnt_propagation(struct vfsmount *, int);
>  int propagate_mnt(struct vfsmount *, struct dentry *, struct vfsmount *,
>  		struct list_head *);




More information about the Containers mailing list