Messages in this thread Patch in this message | | | From | (Eric W. Biederman) | Date | Thu, 06 Nov 2008 02:48:35 -0800 | Subject | [PATCH 2/7] proc: Implement support for automounts in task directories |
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This is a genearl mechanism that is capable of removing any unused mounts on /proc in any directory. As we flush the mounts when a processes dies this mechanism is tailored for flushing mounts in the per task and per task group directories.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> --- fs/proc/Makefile | 1 + fs/proc/automount.c | 29 +++++++++++++++++++++++++++++ fs/proc/internal.h | 3 +++ include/linux/proc_fs.h | 1 + kernel/exit.c | 1 + 5 files changed, 35 insertions(+), 0 deletions(-) create mode 100644 fs/proc/automount.c
diff --git a/fs/proc/Makefile b/fs/proc/Makefile index 63d9651..862a8fe 100644 --- a/fs/proc/Makefile +++ b/fs/proc/Makefile @@ -18,6 +18,7 @@ proc-y += meminfo.o proc-y += stat.o proc-y += uptime.o proc-y += version.o +proc-y += automount.o proc-$(CONFIG_PROC_SYSCTL) += proc_sysctl.o proc-$(CONFIG_NET) += proc_net.o proc-$(CONFIG_PROC_KCORE) += kcore.o diff --git a/fs/proc/automount.c b/fs/proc/automount.c new file mode 100644 index 0000000..a1fabf2 --- /dev/null +++ b/fs/proc/automount.c @@ -0,0 +1,29 @@ +#include <linux/workqueue.h> +#include <linux/mount.h> +#include <linux/vfs.h> +#include "internal.h" + +LIST_HEAD(proc_automounts); + +static void proc_expire_automounts(struct work_struct *work); + +static DECLARE_DELAYED_WORK(proc_automount_task, proc_expire_automounts); +static int proc_automount_timeout = 500 * HZ; + +void proc_shrink_automounts(void) +{ + struct list_head *list = &proc_automounts; + + mark_mounts_for_expiry(list); + mark_mounts_for_expiry(list); + if (list_empty(list)) + return; + + schedule_delayed_work(&proc_automount_task, proc_automount_timeout); +} + +static void proc_expire_automounts(struct work_struct *work) +{ + proc_shrink_automounts(); +} + diff --git a/fs/proc/internal.h b/fs/proc/internal.h index 3e8aeb8..2a8eabb 100644 --- a/fs/proc/internal.h +++ b/fs/proc/internal.h @@ -93,3 +93,6 @@ struct pde_opener { int (*release)(struct inode *, struct file *); struct list_head lh; }; + +extern struct list_head proc_automounts; + diff --git a/include/linux/proc_fs.h b/include/linux/proc_fs.h index b8bdb96..3505a72 100644 --- a/include/linux/proc_fs.h +++ b/include/linux/proc_fs.h @@ -101,6 +101,7 @@ extern spinlock_t proc_subdir_lock; extern void proc_root_init(void); +void proc_shrink_automounts(void); void proc_flush_task(struct task_struct *task); struct dentry *proc_pid_lookup(struct inode *dir, struct dentry * dentry, struct nameidata *); int proc_pid_readdir(struct file * filp, void * dirent, filldir_t filldir); diff --git a/kernel/exit.c b/kernel/exit.c index 80137a5..8a8badb 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -161,6 +161,7 @@ void release_task(struct task_struct * p) repeat: tracehook_prepare_release_task(p); atomic_dec(&p->user->processes); + proc_shrink_automounts(); proc_flush_task(p); write_lock_irq(&tasklist_lock); tracehook_finish_release_task(p); -- 1.5.3.rc6.17.g1911
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