drbd: increase module count on /proc/drbd access

If someone holds /proc/drbd open, previously rmmod would
"succeed" in starting the unload, but then block on remove_proc_entry,
leading to a situation where the lsmod does not show drbd anymore,
but /proc/drbd being still there (but no longer accessible).

I'd rather have rmmod fail up front in this case.

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
This commit is contained in:
Lars Ellenberg 2010-11-24 10:33:02 +01:00 committed by Philipp Reisner
parent c507f46f26
commit 3da127fa88
1 changed files with 11 additions and 2 deletions

View File

@ -34,6 +34,7 @@
#include "drbd_int.h"
static int drbd_proc_open(struct inode *inode, struct file *file);
static int drbd_proc_release(struct inode *inode, struct file *file);
struct proc_dir_entry *drbd_proc;
@ -42,7 +43,7 @@ const struct file_operations drbd_proc_fops = {
.open = drbd_proc_open,
.read = seq_read,
.llseek = seq_lseek,
.release = single_release,
.release = drbd_proc_release,
};
void seq_printf_with_thousands_grouping(struct seq_file *seq, long v)
@ -304,7 +305,15 @@ static int drbd_seq_show(struct seq_file *seq, void *v)
static int drbd_proc_open(struct inode *inode, struct file *file)
{
return single_open(file, drbd_seq_show, PDE(inode)->data);
if (try_module_get(THIS_MODULE))
return single_open(file, drbd_seq_show, PDE(inode)->data);
return -ENODEV;
}
static int drbd_proc_release(struct inode *inode, struct file *file)
{
module_put(THIS_MODULE);
return single_release(inode, file);
}
/* PROC FS stuff end */