This allows to flush dcache entries of a task on multiple procfs mounts per pid namespace.
Maybe this patch is nedded since this is just an optimization and maybe it contains bugs. Signed-off-by: Djalal Harouni <[email protected]> --- fs/proc/base.c | 28 ++++++++++++++++++++++------ fs/proc/inode.c | 13 +++++++++++-- fs/proc/root.c | 13 +++++++++++++ include/linux/pid_namespace.h | 42 ++++++++++++++++++++++++++++++++++++++++++ include/linux/proc_fs.h | 5 +++++ 5 files changed, 93 insertions(+), 8 deletions(-) diff --git a/fs/proc/base.c b/fs/proc/base.c index fd16566..0b96eb1 100644 --- a/fs/proc/base.c +++ b/fs/proc/base.c @@ -1739,7 +1739,6 @@ int pid_getattr(const struct path *path, struct kstat *stat, struct task_struct *task; struct inode *inode = d_inode(path->dentry); struct proc_fs_info *fs_info = proc_sb(inode->i_sb); - struct pid_namespace *pid = fs_info->pid_ns; generic_fillattr(inode, stat); @@ -2967,7 +2966,8 @@ static const struct inode_operations proc_tgid_base_inode_operations = { .permission = proc_pid_permission, }; -static void proc_flush_task_mnt(struct vfsmount *mnt, pid_t pid, pid_t tgid) +static void proc_flush_task_mnt_root(struct dentry *mnt_root, + pid_t pid, pid_t tgid) { struct dentry *dentry, *leader, *dir; char buf[PROC_NUMBUF]; @@ -2976,7 +2976,7 @@ static void proc_flush_task_mnt(struct vfsmount *mnt, pid_t pid, pid_t tgid) name.name = buf; name.len = snprintf(buf, sizeof(buf), "%d", pid); /* no ->d_hash() rejects on procfs */ - dentry = d_hash_and_lookup(mnt->mnt_root, &name); + dentry = d_hash_and_lookup(mnt_root, &name); if (dentry) { d_invalidate(dentry); dput(dentry); @@ -2987,7 +2987,7 @@ static void proc_flush_task_mnt(struct vfsmount *mnt, pid_t pid, pid_t tgid) name.name = buf; name.len = snprintf(buf, sizeof(buf), "%d", tgid); - leader = d_hash_and_lookup(mnt->mnt_root, &name); + leader = d_hash_and_lookup(mnt_root, &name); if (!leader) goto out; @@ -3042,14 +3042,30 @@ void proc_flush_task(struct task_struct *task) int i; struct pid *pid, *tgid; struct upid *upid; + struct proc_fs_info *fs_info_entry; + struct pid_namespace *pid_ns; + struct dentry *mnt_root; pid = task_pid(task); tgid = task_tgid(task); for (i = 0; i <= pid->level; i++) { upid = &pid->numbers[i]; - proc_flush_task_mnt(upid->ns->proc_mnt, upid->nr, - tgid->numbers[i].nr); + pid_ns = upid->ns; + + pidns_procfs_lock_shared(pid_ns); + list_for_each_entry(fs_info_entry, &pid_ns->procfs_mounts, + pidns_entry) { + if (proc_fs_get_unshare(fs_info_entry) == PROC_FS_V2) { + mnt_root = fs_info_entry->sb->s_root; + proc_flush_task_mnt_root(mnt_root, upid->nr, + tgid->numbers[i].nr); + } + } + pidns_procfs_unlock_shared(pid_ns); + + mnt_root = pid_ns->proc_mnt->mnt_root; + proc_flush_task_mnt_root(mnt_root, upid->nr, tgid->numbers[i].nr); } } diff --git a/fs/proc/inode.c b/fs/proc/inode.c index 5f7557d..73e49b3 100644 --- a/fs/proc/inode.c +++ b/fs/proc/inode.c @@ -478,10 +478,19 @@ struct inode *proc_get_inode(struct super_block *sb, struct proc_dir_entry *de) int proc_fill_super(struct super_block *s, void *data, int silent) { struct proc_fs_info *fs_info = proc_sb(s); + struct pid_namespace *ns = get_pid_ns(fs_info->pid_ns); struct inode *root_inode; - int ret; + int ret, version; - get_pid_ns(fs_info->pid_ns); + fs_info->sb = s; + + version = proc_fs_get_unshare(fs_info); + + if (version == PROC_FS_V2) { + pidns_procfs_lock(ns); + list_add_tail(&fs_info->pidns_entry, &ns->procfs_mounts); + pidns_procfs_unlock(ns); + } if (!proc_parse_options(data, fs_info)) return -EINVAL; diff --git a/fs/proc/root.c b/fs/proc/root.c index 7a8f425..73f972f 100644 --- a/fs/proc/root.c +++ b/fs/proc/root.c @@ -222,6 +222,7 @@ static struct dentry *proc_mount(struct file_system_type *fs_type, static void proc_destroy_sb(struct super_block *sb) { + int version; struct proc_fs_info *fs_info = proc_sb(sb); struct pid_namespace *ns = (struct pid_namespace *)fs_info->pid_ns; @@ -229,6 +230,15 @@ static void proc_destroy_sb(struct super_block *sb) dput(ns->proc_self); if (ns->proc_thread_self) dput(ns->proc_thread_self); + + version = proc_fs_get_unshare(fs_info); + + if (version == PROC_FS_V2) { + pidns_procfs_lock(ns); + list_del(&fs_info->pidns_entry); + pidns_procfs_unlock(ns); + } + kill_anon_super(sb); put_pid_ns(ns); kfree(fs_info); @@ -352,6 +362,9 @@ int pid_ns_prepare_proc(struct pid_namespace *ns) return PTR_ERR(mnt); ns->proc_mnt = mnt; + init_rwsem(&ns->rw_procfs_mnts); + INIT_LIST_HEAD(&ns->procfs_mounts); + return 0; } diff --git a/include/linux/pid_namespace.h b/include/linux/pid_namespace.h index c2a989d..05639c8 100644 --- a/include/linux/pid_namespace.h +++ b/include/linux/pid_namespace.h @@ -41,6 +41,8 @@ struct pid_namespace { struct vfsmount *proc_mnt; struct dentry *proc_self; struct dentry *proc_thread_self; + struct rw_semaphore rw_procfs_mnts; + struct list_head procfs_mounts; /* list of separated procfs mounts */ #endif #ifdef CONFIG_BSD_PROCESS_ACCT struct fs_pin *bacct; @@ -107,4 +109,44 @@ extern struct pid_namespace *task_active_pid_ns(struct task_struct *tsk); void pidhash_init(void); void pidmap_init(void); +#ifdef CONFIG_PROC_FS +static inline void pidns_procfs_lock(struct pid_namespace *pid_ns) +{ + down_write(&pid_ns->rw_procfs_mnts); +} + +static inline void pidns_procfs_unlock(struct pid_namespace *pid_ns) +{ + up_write(&pid_ns->rw_procfs_mnts); +} + +static inline void pidns_procfs_lock_shared(struct pid_namespace *pid_ns) +{ + down_read(&pid_ns->rw_procfs_mnts); +} + +static inline void pidns_procfs_unlock_shared(struct pid_namespace *pid_ns) +{ + up_read(&pid_ns->rw_procfs_mnts); +} +#else /* !CONFIG_PROC_FS */ + +static inline void pidns_procfs_lock(struct pid_namespace *pid_ns) +{ +} + +static inline void pidns_procfs_unlock(struct pid_namespace *pid_ns) +{ +} + +static inline void pidns_procfs_lock_shared(struct pid_namespace *pid_ns) +{ +} + +static inline void pidns_procfs_unlock_shared(struct pid_namespace *pid_ns) +{ +} + +#endif /* CONFIG_PROC_FS */ + #endif /* _LINUX_PID_NS_H */ diff --git a/include/linux/proc_fs.h b/include/linux/proc_fs.h index e3a78a5..b2200e3 100644 --- a/include/linux/proc_fs.h +++ b/include/linux/proc_fs.h @@ -15,7 +15,12 @@ enum { struct proc_fs_info { refcount_t users; + + struct super_block *sb; struct pid_namespace *pid_ns; + + struct list_head pidns_entry; /* Node in procfs_mounts of a pidns */ + kgid_t pid_gid; int hide_pid; int version; -- 2.10.2
