diff options
Diffstat (limited to 'fs/nsfs.c')
| -rw-r--r-- | fs/nsfs.c | 124 |
1 files changed, 42 insertions, 82 deletions
@@ -27,26 +27,17 @@ static const struct file_operations ns_file_operations = { static char *ns_dname(struct dentry *dentry, char *buffer, int buflen) { struct inode *inode = d_inode(dentry); - const struct proc_ns_operations *ns_ops = dentry->d_fsdata; + struct ns_common *ns = inode->i_private; + const struct proc_ns_operations *ns_ops = ns->ops; return dynamic_dname(buffer, buflen, "%s:[%lu]", ns_ops->name, inode->i_ino); } -static void ns_prune_dentry(struct dentry *dentry) -{ - struct inode *inode = d_inode(dentry); - if (inode) { - struct ns_common *ns = inode->i_private; - atomic_long_set(&ns->stashed, 0); - } -} - -const struct dentry_operations ns_dentry_operations = -{ - .d_prune = ns_prune_dentry, +const struct dentry_operations ns_dentry_operations = { .d_delete = always_delete_dentry, .d_dname = ns_dname, + .d_prune = stashed_dentry_prune, }; static void nsfs_evict(struct inode *inode) @@ -56,67 +47,16 @@ static void nsfs_evict(struct inode *inode) ns->ops->put(ns); } -static int __ns_get_path(struct path *path, struct ns_common *ns) -{ - struct vfsmount *mnt = nsfs_mnt; - struct dentry *dentry; - struct inode *inode; - unsigned long d; - - rcu_read_lock(); - d = atomic_long_read(&ns->stashed); - if (!d) - goto slow; - dentry = (struct dentry *)d; - if (!lockref_get_not_dead(&dentry->d_lockref)) - goto slow; - rcu_read_unlock(); - ns->ops->put(ns); -got_it: - path->mnt = mntget(mnt); - path->dentry = dentry; - return 0; -slow: - rcu_read_unlock(); - inode = new_inode_pseudo(mnt->mnt_sb); - if (!inode) { - ns->ops->put(ns); - return -ENOMEM; - } - inode->i_ino = ns->inum; - simple_inode_init_ts(inode); - inode->i_flags |= S_IMMUTABLE; - inode->i_mode = S_IFREG | S_IRUGO; - inode->i_fop = &ns_file_operations; - inode->i_private = ns; - - dentry = d_make_root(inode); /* not the normal use, but... */ - if (!dentry) - return -ENOMEM; - dentry->d_fsdata = (void *)ns->ops; - d = atomic_long_cmpxchg(&ns->stashed, 0, (unsigned long)dentry); - if (d) { - d_delete(dentry); /* make sure ->d_prune() does nothing */ - dput(dentry); - cpu_relax(); - return -EAGAIN; - } - goto got_it; -} - int ns_get_path_cb(struct path *path, ns_get_path_helper_t *ns_get_cb, void *private_data) { - int ret; + struct ns_common *ns; - do { - struct ns_common *ns = ns_get_cb(private_data); - if (!ns) - return -ENOENT; - ret = __ns_get_path(path, ns); - } while (ret == -EAGAIN); + ns = ns_get_cb(private_data); + if (!ns) + return -ENOENT; - return ret; + return path_from_stashed(&ns->stashed, nsfs_mnt, ns, path); } struct ns_get_path_task_args { @@ -146,6 +86,7 @@ int open_related_ns(struct ns_common *ns, struct ns_common *(*get_ns)(struct ns_common *ns)) { struct path path = {}; + struct ns_common *relative; struct file *f; int err; int fd; @@ -154,19 +95,14 @@ int open_related_ns(struct ns_common *ns, if (fd < 0) return fd; - do { - struct ns_common *relative; - - relative = get_ns(ns); - if (IS_ERR(relative)) { - put_unused_fd(fd); - return PTR_ERR(relative); - } - - err = __ns_get_path(&path, relative); - } while (err == -EAGAIN); + relative = get_ns(ns); + if (IS_ERR(relative)) { + put_unused_fd(fd); + return PTR_ERR(relative); + } - if (err) { + err = path_from_stashed(&relative->stashed, nsfs_mnt, relative, &path); + if (err < 0) { put_unused_fd(fd); return err; } @@ -249,7 +185,8 @@ bool ns_match(const struct ns_common *ns, dev_t dev, ino_t ino) static int nsfs_show_path(struct seq_file *seq, struct dentry *dentry) { struct inode *inode = d_inode(dentry); - const struct proc_ns_operations *ns_ops = dentry->d_fsdata; + const struct ns_common *ns = inode->i_private; + const struct proc_ns_operations *ns_ops = ns->ops; seq_printf(seq, "%s:[%lu]", ns_ops->name, inode->i_ino); return 0; @@ -261,6 +198,28 @@ static const struct super_operations nsfs_ops = { .show_path = nsfs_show_path, }; +static int nsfs_init_inode(struct inode *inode, void *data) +{ + struct ns_common *ns = data; + + inode->i_private = data; + inode->i_mode |= S_IRUGO; + inode->i_fop = &ns_file_operations; + inode->i_ino = ns->inum; + return 0; +} + +static void nsfs_put_data(void *data) +{ + struct ns_common *ns = data; + ns->ops->put(ns); +} + +static const struct stashed_operations nsfs_stashed_ops = { + .init_inode = nsfs_init_inode, + .put_data = nsfs_put_data, +}; + static int nsfs_init_fs_context(struct fs_context *fc) { struct pseudo_fs_context *ctx = init_pseudo(fc, NSFS_MAGIC); @@ -268,6 +227,7 @@ static int nsfs_init_fs_context(struct fs_context *fc) return -ENOMEM; ctx->ops = &nsfs_ops; ctx->dops = &ns_dentry_operations; + fc->s_fs_info = (void *)&nsfs_stashed_ops; return 0; } |