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