lkml.org 
[lkml]   [2007]   [Nov]   [21]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: 2.6.24-rc3: find complains about /proc/net
    Eric W. Biederman wrote:
    > Below is a preliminary patch. It solves the directory issue but it doesn't
    > play well with proc_mnt and proc_flush_task. It works by simply caching the
    > network namespace when we mount proc so we don't have to be fancy and dynamic.

    Nice... Where should we apply this patch to?

    > Something for the discussion anyway.
    >
    > I will start sorting out what makes sense tomorrow.
    >
    > Eric
    >
    >
    >>From f359fde2469ba8be2123a465e788a83c7e6831e9 Mon Sep 17 00:00:00 2001
    > From: Eric W. Biederman <ebiederm@xmission.com>
    > Date: Tue, 20 Nov 2007 19:36:05 -0700
    > Subject: [PATCH] proc: Fix /proc/net directory listings.
    >
    > Having proc dynamically display the contents of /proc/net is
    > hard. So make life simpler by capturing the network namespace
    > when we mount proc and only displaying that network namespace.
    >
    > ---
    > fs/proc/base.c | 8 ++--
    > fs/proc/generic.c | 4 ++-
    > fs/proc/internal.h | 13 +++++++
    > fs/proc/proc_net.c | 89 ++++-------------------------------------------
    > fs/proc/root.c | 50 ++++++++++++++++++--------
    > include/linux/proc_fs.h | 4 ++
    > 6 files changed, 66 insertions(+), 102 deletions(-)
    >
    > diff --git a/fs/proc/base.c b/fs/proc/base.c
    > index aeaf0d0..9d4f06a 100644
    > --- a/fs/proc/base.c
    > +++ b/fs/proc/base.c
    > @@ -2395,7 +2395,7 @@ struct dentry *proc_pid_lookup(struct inode *dir, struct dentry * dentry, struct
    > if (tgid == ~0U)
    > goto out;
    >
    > - ns = dentry->d_sb->s_fs_info;
    > + ns = proc_sbi(dentry->d_sb)->pid_ns;
    > rcu_read_lock();
    > task = find_task_by_pid_ns(tgid, ns);
    > if (task)
    > @@ -2476,7 +2476,7 @@ int proc_pid_readdir(struct file * filp, void * dirent, filldir_t filldir)
    > goto out;
    > }
    >
    > - ns = filp->f_dentry->d_sb->s_fs_info;
    > + ns = proc_sbi(filp->f_dentry->d_sb)->pid_ns;
    > tgid = filp->f_pos - TGID_OFFSET;
    > for (task = next_tgid(tgid, ns);
    > task;
    > @@ -2615,7 +2615,7 @@ static struct dentry *proc_task_lookup(struct inode *dir, struct dentry * dentry
    > if (tid == ~0U)
    > goto out;
    >
    > - ns = dentry->d_sb->s_fs_info;
    > + ns = proc_sbi(dentry->d_sb)->pid_ns;
    > rcu_read_lock();
    > task = find_task_by_pid_ns(tid, ns);
    > if (task)
    > @@ -2758,7 +2758,7 @@ static int proc_task_readdir(struct file * filp, void * dirent, filldir_t filldi
    > /* f_version caches the tgid value that the last readdir call couldn't
    > * return. lseek aka telldir automagically resets f_version to 0.
    > */
    > - ns = filp->f_dentry->d_sb->s_fs_info;
    > + ns = proc_sbi(filp->f_dentry->d_sb)->pid_ns;
    > tid = (int)filp->f_version;
    > filp->f_version = 0;
    > for (task = first_tid(leader, tid, pos - 2, ns);
    > diff --git a/fs/proc/generic.c b/fs/proc/generic.c
    > index 1bdb624..b58f0ec 100644
    > --- a/fs/proc/generic.c
    > +++ b/fs/proc/generic.c
    > @@ -398,7 +398,9 @@ struct dentry *proc_lookup(struct inode * dir, struct dentry *dentry, struct nam
    > continue;
    > if (!memcmp(dentry->d_name.name, de->name, de->namelen)) {
    > unsigned int ino = de->low_ino;
    > -
    > +
    > + if (de->shadow_proc)
    > + de = de->shadow_proc(dentry->d_sb, de);
    > de_get(de);
    > spin_unlock(&proc_subdir_lock);
    > error = -EINVAL;
    > diff --git a/fs/proc/internal.h b/fs/proc/internal.h
    > index 1820eb2..a26f115 100644
    > --- a/fs/proc/internal.h
    > +++ b/fs/proc/internal.h
    > @@ -11,6 +11,18 @@
    >
    > #include <linux/proc_fs.h>
    >
    > +struct pid_namespace;
    > +struct net;
    > +struct proc_sb_info {
    > + struct pid_namespace *pid_ns;
    > + struct net *net_ns;
    > +};
    > +
    > +static inline struct proc_sb_info *proc_sbi(struct super_block *sb)
    > +{
    > + return sb->s_fs_info;
    > +}
    > +
    > #ifdef CONFIG_PROC_SYSCTL
    > extern int proc_sys_init(void);
    > #else
    > @@ -78,3 +90,4 @@ static inline int proc_fd(struct inode *inode)
    > {
    > return PROC_I(inode)->fd;
    > }
    > +
    > diff --git a/fs/proc/proc_net.c b/fs/proc/proc_net.c
    > index 131f9c6..8a82e29 100644
    > --- a/fs/proc/proc_net.c
    > +++ b/fs/proc/proc_net.c
    > @@ -50,89 +50,15 @@ struct net *get_proc_net(const struct inode *inode)
    > }
    > EXPORT_SYMBOL_GPL(get_proc_net);
    >
    > -static struct proc_dir_entry *proc_net_shadow;
    > +static struct proc_dir_entry *shadow_pde;
    >
    > -static struct dentry *proc_net_shadow_dentry(struct dentry *parent,
    > - struct proc_dir_entry *de)
    > +static struct proc_dir_entry *proc_net_shadow(struct super_block *sb,
    > + struct proc_dir_entry *de)
    > {
    > - struct dentry *shadow = NULL;
    > - struct inode *inode;
    > - if (!de)
    > - goto out;
    > - de_get(de);
    > - inode = proc_get_inode(parent->d_inode->i_sb, de->low_ino, de);
    > - if (!inode)
    > - goto out_de_put;
    > - shadow = d_alloc_name(parent, de->name);
    > - if (!shadow)
    > - goto out_iput;
    > - shadow->d_op = parent->d_op; /* proc_dentry_operations */
    > - d_instantiate(shadow, inode);
    > -out:
    > - return shadow;
    > -out_iput:
    > - iput(inode);
    > -out_de_put:
    > - de_put(de);
    > - goto out;
    > -}
    > -
    > -static void *proc_net_follow_link(struct dentry *parent, struct nameidata *nd)
    > -{
    > - struct net *net = current->nsproxy->net_ns;
    > - struct dentry *shadow;
    > - shadow = proc_net_shadow_dentry(parent, net->proc_net);
    > - if (!shadow)
    > - return ERR_PTR(-ENOENT);
    > -
    > - dput(nd->dentry);
    > - /* My dentry count is 1 and that should be enough as the
    > - * shadow dentry is thrown away immediately.
    > - */
    > - nd->dentry = shadow;
    > - return NULL;
    > + struct proc_sb_info *sbi = proc_sbi(sb);
    > + return sbi->net_ns->proc_net;
    > }
    >
    > -static struct dentry *proc_net_lookup(struct inode *dir, struct dentry *dentry,
    > - struct nameidata *nd)
    > -{
    > - struct net *net = current->nsproxy->net_ns;
    > - struct dentry *shadow;
    > -
    > - shadow = proc_net_shadow_dentry(nd->dentry, net->proc_net);
    > - if (!shadow)
    > - return ERR_PTR(-ENOENT);
    > -
    > - dput(nd->dentry);
    > - nd->dentry = shadow;
    > -
    > - return shadow->d_inode->i_op->lookup(shadow->d_inode, dentry, nd);
    > -}
    > -
    > -static int proc_net_setattr(struct dentry *dentry, struct iattr *iattr)
    > -{
    > - struct net *net = current->nsproxy->net_ns;
    > - struct dentry *shadow;
    > - int ret;
    > -
    > - shadow = proc_net_shadow_dentry(dentry->d_parent, net->proc_net);
    > - if (!shadow)
    > - return -ENOENT;
    > - ret = shadow->d_inode->i_op->setattr(shadow, iattr);
    > - dput(shadow);
    > - return ret;
    > -}
    > -
    > -static const struct file_operations proc_net_dir_operations = {
    > - .read = generic_read_dir,
    > -};
    > -
    > -static struct inode_operations proc_net_dir_inode_operations = {
    > - .follow_link = proc_net_follow_link,
    > - .lookup = proc_net_lookup,
    > - .setattr = proc_net_setattr,
    > -};
    > -
    > static __net_init int proc_net_ns_init(struct net *net)
    > {
    > struct proc_dir_entry *root, *netd, *net_statd;
    > @@ -185,9 +111,8 @@ static struct pernet_operations __net_initdata proc_net_ns_ops = {
    >
    > int __init proc_net_init(void)
    > {
    > - proc_net_shadow = proc_mkdir("net", NULL);
    > - proc_net_shadow->proc_iops = &proc_net_dir_inode_operations;
    > - proc_net_shadow->proc_fops = &proc_net_dir_operations;
    > + shadow_pde = proc_mkdir("net", NULL);
    > + shadow_pde->shadow_proc = proc_net_shadow;
    >
    > return register_pernet_subsys(&proc_net_ns_ops);
    > }
    > diff --git a/fs/proc/root.c b/fs/proc/root.c
    > index ec9cb3b..e60ac83 100644
    > --- a/fs/proc/root.c
    > +++ b/fs/proc/root.c
    > @@ -19,6 +19,7 @@
    > #include <linux/smp_lock.h>
    > #include <linux/mount.h>
    > #include <linux/pid_namespace.h>
    > +#include <net/net_namespace.h>
    >
    > #include "internal.h"
    >
    > @@ -26,15 +27,23 @@ struct proc_dir_entry *proc_bus, *proc_root_fs, *proc_root_driver;
    >
    > static int proc_test_super(struct super_block *sb, void *data)
    > {
    > - return sb->s_fs_info == data;
    > + struct proc_sb_info *sbi = proc_sbi(sb), *info = data;
    > + return (sbi->pid_ns == info->pid_ns) &&
    > + (sbi->net_ns == info->net_ns);
    > }
    >
    > static int proc_set_super(struct super_block *sb, void *data)
    > {
    > - struct pid_namespace *ns;
    > -
    > - ns = (struct pid_namespace *)data;
    > - sb->s_fs_info = get_pid_ns(ns);
    > +
    > + struct proc_sb_info *new, *info = data;
    > +
    > + new = kzalloc(sizeof(*new), GFP_KERNEL);
    > + if (!new)
    > + return -ENOMEM;
    > + *new = *info;
    > + get_pid_ns(new->pid_ns);
    > + get_net(new->net_ns);
    > + sb->s_fs_info = new;
    > return set_anon_super(sb, NULL);
    > }
    >
    > @@ -43,7 +52,7 @@ static int proc_get_sb(struct file_system_type *fs_type,
    > {
    > int err;
    > struct super_block *sb;
    > - struct pid_namespace *ns;
    > + struct proc_sb_info info, *sbi;
    > struct proc_inode *ei;
    >
    > if (proc_mnt) {
    > @@ -57,12 +66,14 @@ static int proc_get_sb(struct file_system_type *fs_type,
    > ei->pid = find_get_pid(1);
    > }
    >
    > + info.pid_ns = current->nsproxy->pid_ns;
    > + info.net_ns = current->nsproxy->net_ns;
    > if (flags & MS_KERNMOUNT)
    > - ns = (struct pid_namespace *)data;
    > + sbi = data;
    > else
    > - ns = current->nsproxy->pid_ns;
    > + sbi = &info;
    >
    > - sb = sget(fs_type, proc_test_super, proc_set_super, ns);
    > + sb = sget(fs_type, proc_test_super, proc_set_super, sbi);
    > if (IS_ERR(sb))
    > return PTR_ERR(sb);
    >
    > @@ -78,12 +89,13 @@ static int proc_get_sb(struct file_system_type *fs_type,
    > ei = PROC_I(sb->s_root->d_inode);
    > if (!ei->pid) {
    > rcu_read_lock();
    > - ei->pid = get_pid(find_pid_ns(1, ns));
    > + ei->pid = get_pid(find_pid_ns(1, sbi->pid_ns));
    > rcu_read_unlock();
    > }
    >
    > sb->s_flags |= MS_ACTIVE;
    > - ns->proc_mnt = mnt;
    > + if (!sbi->pid_ns->proc_mnt)
    > + sbi->pid_ns->proc_mnt = mnt;
    > }
    >
    > return simple_set_mnt(mnt, sb);
    > @@ -91,11 +103,13 @@ static int proc_get_sb(struct file_system_type *fs_type,
    >
    > static void proc_kill_sb(struct super_block *sb)
    > {
    > - struct pid_namespace *ns;
    > + struct proc_sb_info *sbi;
    >
    > - ns = (struct pid_namespace *)sb->s_fs_info;
    > + sbi = proc_sbi(sb);
    > kill_anon_super(sb);
    > - put_pid_ns(ns);
    > + put_pid_ns(sbi->pid_ns);
    > + put_net(sbi->net_ns);
    > + kfree(sbi);
    > }
    >
    > static struct file_system_type proc_fs_type = {
    > @@ -106,13 +120,16 @@ static struct file_system_type proc_fs_type = {
    >
    > void __init proc_root_init(void)
    > {
    > + struct proc_sb_info info;
    > int err = proc_init_inodecache();
    > if (err)
    > return;
    > err = register_filesystem(&proc_fs_type);
    > if (err)
    > return;
    > - proc_mnt = kern_mount_data(&proc_fs_type, &init_pid_ns);
    > + info.pid_ns = &init_pid_ns;
    > + info.net_ns = current->nsproxy->net_ns;
    > + proc_mnt = kern_mount_data(&proc_fs_type, &info);
    > err = PTR_ERR(proc_mnt);
    > if (IS_ERR(proc_mnt)) {
    > unregister_filesystem(&proc_fs_type);
    > @@ -214,8 +231,11 @@ struct proc_dir_entry proc_root = {
    >
    > int pid_ns_prepare_proc(struct pid_namespace *ns)
    > {
    > + struct proc_sb_info info;
    > struct vfsmount *mnt;
    >
    > + info.pid_ns = ns;
    > + info.net_ns = current->nsproxy->net_ns;
    > mnt = kern_mount_data(&proc_fs_type, ns);
    > if (IS_ERR(mnt))
    > return PTR_ERR(mnt);
    > diff --git a/include/linux/proc_fs.h b/include/linux/proc_fs.h
    > index 2b3c1d8..c22c558 100644
    > --- a/include/linux/proc_fs.h
    > +++ b/include/linux/proc_fs.h
    > @@ -48,6 +48,9 @@ typedef int (read_proc_t)(char *page, char **start, off_t off,
    > typedef int (write_proc_t)(struct file *file, const char __user *buffer,
    > unsigned long count, void *data);
    > typedef int (get_info_t)(char *, char **, off_t, int);
    > +struct proc_dir_entry;
    > +typedef struct proc_dir_entry *(shadow_proc_t)(struct super_block *sb,
    > + struct proc_dir_entry *pde);
    >
    > struct proc_dir_entry {
    > unsigned int low_ino;
    > @@ -79,6 +82,7 @@ struct proc_dir_entry {
    > int pde_users; /* number of callers into module in progress */
    > spinlock_t pde_unload_lock; /* proc_fops checks and pde_users bumps */
    > struct completion *pde_unload_completion;
    > + shadow_proc_t *shadow_proc;
    > };
    >
    > struct kcore_list {

    -
    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to majordomo@vger.kernel.org
    More majordomo info at http://vger.kernel.org/majordomo-info.html
    Please read the FAQ at http://www.tux.org/lkml/

    \
     
     \ /
      Last update: 2007-11-21 10:41    [W:0.052 / U:249.660 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site