From: Miklos Szeredi <mszeredi@xxxxxxx>
Allow /proc/<pid>/mountinfo to use the root of <pid> to calculate
mountpoints.
- move definition of 'struct proc_mounts' to <linux/mnt_namespace.h>
- add the process's namespace and root to this structure
- pass a pointer to 'struct proc_mounts' into seq_operations
In addition the following cleanups are made:
- use a common open function for /proc/<pid>/{mounts,mountstat}
- surround namespace.c part of these proc files with #ifdef CONFIG_PROC_FS
- make the seq_operations structures const
Signed-off-by: Miklos Szeredi <mszeredi@xxxxxxx>
---
fs/namespace.c | 14 +++--
fs/proc/base.c | 108 +++++++++++++++++++-----------------------
include/linux/mnt_namespace.h | 11 ++++
3 files changed, 70 insertions(+), 63 deletions(-)
Index: vfs-2.6/fs/namespace.c
===================================================================
--- vfs-2.6.orig/fs/namespace.c 2008-03-26 21:39:49.000000000 +0100
+++ vfs-2.6/fs/namespace.c 2008-03-26 21:43:03.000000000 +0100
@@ -731,20 +731,21 @@ void save_mount_options(struct super_blo
}
EXPORT_SYMBOL(save_mount_options);
+#ifdef CONFIG_PROC_FS
/* iterator */
static void *m_start(struct seq_file *m, loff_t *pos)
{
- struct mnt_namespace *n = m->private;
+ struct proc_mounts *p = m->private;
down_read(&namespace_sem);
- return seq_list_start(&n->list, *pos);
+ return seq_list_start(&p->ns->list, *pos);
}
static void *m_next(struct seq_file *m, void *v, loff_t *pos)
{
- struct mnt_namespace *n = m->private;
+ struct proc_mounts *p = m->private;
- return seq_list_next(v, &n->list, pos);
+ return seq_list_next(v, &p->ns->list, pos);
}
static void m_stop(struct seq_file *m, void *v)
@@ -801,7 +802,7 @@ static int show_vfsmnt(struct seq_file *
return err;
}
-struct seq_operations mounts_op = {
+const struct seq_operations mounts_op = {
.start = m_start,
.next = m_next,
.stop = m_stop,
@@ -840,12 +841,13 @@ static int show_vfsstat(struct seq_file
return err;
}
-struct seq_operations mountstats_op = {
+const struct seq_operations mountstats_op = {
.start = m_start,
.next = m_next,
.stop = m_stop,
.show = show_vfsstat,
};
+#endif /* CONFIG_PROC_FS */
/**
* may_umount_tree - check if a mount tree is busy
Index: vfs-2.6/fs/proc/base.c
===================================================================
--- vfs-2.6.orig/fs/proc/base.c 2008-03-26 21:37:52.000000000 +0100
+++ vfs-2.6/fs/proc/base.c 2008-03-26 21:43:03.000000000 +0100
@@ -502,17 +502,14 @@ static const struct inode_operations pro
.setattr = proc_setattr,
};
-extern const 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_common(struct inode *inode, struct file *file,
+ const struct seq_operations *op)
{
struct task_struct *task = get_proc_task(inode);
struct nsproxy *nsp;
struct mnt_namespace *ns = NULL;
+ struct fs_struct *fs = NULL;
+ struct path root;
struct proc_mounts *p;
int ret = -EINVAL;
@@ -525,40 +522,61 @@ static int mounts_open(struct inode *ino
get_mnt_ns(ns);
}
rcu_read_unlock();
-
+ if (ns)
+ fs = get_fs_struct(task);
put_task_struct(task);
}
- if (ns) {
- ret = -ENOMEM;
- p = kmalloc(sizeof(struct proc_mounts), GFP_KERNEL);
- if (p) {
- file->private_data = &p->m;
- ret = seq_open(file, &mounts_op);
- if (!ret) {
- p->m.private = ns;
- p->event = ns->event;
- return 0;
- }
- kfree(p);
- }
- put_mnt_ns(ns);
- }
+ if (!ns)
+ goto err;
+ if (!fs)
+ goto err_put_ns;
+
+ read_lock(&fs->lock);
+ root = fs->root;
+ path_get(&root);
+ read_unlock(&fs->lock);
+ put_fs_struct(fs);
+
+ ret = -ENOMEM;
+ p = kmalloc(sizeof(struct proc_mounts), GFP_KERNEL);
+ if (!p)
+ goto err_put_path;
+
+ file->private_data = &p->m;
+ ret = seq_open(file, op);
+ if (ret)
+ goto err_free;
+
+ p->m.private = p;
+ p->ns = ns;
+ p->root = root;
+ p->event = ns->event;
+
+ return 0;
+
+ err_free:
+ kfree(p);
+ err_put_path:
+ path_put(&root);
+ err_put_ns:
+ put_mnt_ns(ns);
+ err:
return ret;
}
static int mounts_release(struct inode *inode, struct file *file)
{
- struct seq_file *m = file->private_data;
- struct mnt_namespace *ns = m->private;
- put_mnt_ns(ns);
+ struct proc_mounts *p = file->private_data;
+ path_put(&p->root);
+ put_mnt_ns(p->ns);
return seq_release(inode, file);
}
static unsigned mounts_poll(struct file *file, poll_table *wait)
{
struct proc_mounts *p = file->private_data;
- struct mnt_namespace *ns = p->m.private;
+ struct mnt_namespace *ns = p->ns;
unsigned res = 0;
poll_wait(file, &ns->poll, wait);
@@ -573,6 +591,11 @@ static unsigned mounts_poll(struct file
return res;
}
+static int mounts_open(struct inode *inode, struct file *file)
+{
+ return mounts_open_common(inode, file, &mounts_op);
+}
+
static const struct file_operations proc_mounts_operations = {
.open = mounts_open,
.read = seq_read,
@@ -581,38 +604,9 @@ static const struct file_operations proc
.poll = mounts_poll,
};
-extern const struct seq_operations mountstats_op;
static int mountstats_open(struct inode *inode, struct file *file)
{
- int ret = seq_open(file, &mountstats_op);
-
- if (!ret) {
- struct seq_file *m = file->private_data;
- struct nsproxy *nsp;
- struct mnt_namespace *mnt_ns = NULL;
- struct task_struct *task = get_proc_task(inode);
-
- if (task) {
- rcu_read_lock();
- nsp = task_nsproxy(task);
- if (nsp) {
- mnt_ns = nsp->mnt_ns;
- if (mnt_ns)
- get_mnt_ns(mnt_ns);
- }
- rcu_read_unlock();
-
- put_task_struct(task);
- }
-
- if (mnt_ns)
- m->private = mnt_ns;
- else {
- seq_release(inode, file);
- ret = -EINVAL;
- }
- }
- return ret;
+ return mounts_open_common(inode, file, &mountstats_op);
}
static const struct file_operations proc_mountstats_operations = {
Index: vfs-2.6/include/linux/mnt_namespace.h
===================================================================
--- vfs-2.6.orig/include/linux/mnt_namespace.h 2008-03-26 21:37:52.000000000 +0100
+++ vfs-2.6/include/linux/mnt_namespace.h 2008-03-26 21:43:03.000000000 +0100
@@ -5,6 +5,7 @@
#include <linux/mount.h>
#include <linux/sched.h>
#include <linux/nsproxy.h>
+#include <linux/seq_file.h>
struct mnt_namespace {
atomic_t count;
@@ -14,6 +15,13 @@ struct mnt_namespace {
int event;
};
+struct proc_mounts {
+ struct seq_file m; /* must be the first element */
+ struct mnt_namespace *ns;
+ struct path root;
+ int event;
+};
+
extern struct mnt_namespace *copy_mnt_ns(unsigned long, struct mnt_namespace *,
struct fs_struct *);
extern void __put_mnt_ns(struct mnt_namespace *ns);
@@ -37,5 +45,8 @@ static inline void get_mnt_ns(struct mnt
atomic_inc(&ns->count);
}
+extern const struct seq_operations mounts_op;
+extern const struct seq_operations mountstats_op;
+
#endif
#endif
--
--
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