On Fri, May 18, 2012 at 11:23:27AM -0700, Linus Torvalds wrote:
> On Fri, May 18, 2012 at 11:18 AM, Linus Torvalds
> <torvalds@xxxxxxxxxxxxxxxxxxxx> wrote:
> >
> > Doing it at getattr() time does sound good.
> >
> > Let me try to cook something up.
>
> Ugh. It's a much bigger patch, because we share the inode operations
> with other cases too.
>
> So I think that would fall under the "further cleanup" heading, and
> I'm not going to do it now. Not with 3.4 imminent.
>
> But if you were to do such a cleanup later...
It's actually not big. Completely untested minimal variant (without
touching ->d_revalidate()):
diff --git a/fs/proc/base.c b/fs/proc/base.c
index 1c8b280..b2a8b8f 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -1491,6 +1491,44 @@ static const struct inode_operations proc_pid_link_inode_operations = {
.setattr = proc_setattr,
};
+static int proc_fd_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat)
+{
+ struct inode *inode = dentry->d_inode;
+ struct files_struct *files;
+ struct task_struct *task;
+ struct file *file;
+ fmode_t mode = 0;
+
+ generic_fillattr(inode, stat);
+
+ rcu_read_lock();
+ task = pid_task(proc_pid(inode), PIDTYPE_PID);
+ files = task ? get_files_struct(task) : NULL;
+ file = files ? fcheck_files(files, PROC_I(inode)->fd) : NULL;
+ if (file)
+ mode = file->f_mode;
+ rcu_read_unlock();
+
+ if (files)
+ put_files_struct(files);
+ if (!file)
+ return -ENOENT;
+
+ if (mode & FMODE_READ)
+ stat->mode |= S_IRUSR | S_IXUSR;
+ if (mode & FMODE_WRITE)
+ stat->mode |= S_IWUSR | S_IXUSR;
+ stat->size = 64;
+ return 0;
+}
+
+static const struct inode_operations proc_pid_fd_inode_operations = {
+ .readlink = proc_pid_readlink,
+ .follow_link = proc_pid_follow_link,
+ .setattr = proc_setattr,
+ .getattr = proc_fd_getattr,
+};
+
/* building an inode */
@@ -1851,25 +1889,16 @@ static struct dentry *proc_fd_instantiate(struct inode *dir,
files = get_files_struct(task);
if (!files)
goto out_iput;
- inode->i_mode = S_IFLNK;
- /*
- * We are not taking a ref to the file structure, so we must
- * hold ->file_lock.
- */
- spin_lock(&files->file_lock);
+ rcu_read_lock();
file = fcheck_files(files, fd);
- if (!file)
- goto out_unlock;
- if (file->f_mode & FMODE_READ)
- inode->i_mode |= S_IRUSR | S_IXUSR;
- if (file->f_mode & FMODE_WRITE)
- inode->i_mode |= S_IWUSR | S_IXUSR;
- spin_unlock(&files->file_lock);
+ rcu_read_unlock();
put_files_struct(files);
+ if (!file)
+ goto out_iput;
- inode->i_op = &proc_pid_link_inode_operations;
- inode->i_size = 64;
+ inode->i_mode = S_IFLNK;
+ inode->i_op = &proc_pid_fd_inode_operations;
ei->op.proc_get_link = proc_fd_link;
d_set_d_op(dentry, &tid_fd_dentry_operations);
d_add(dentry, inode);
@@ -1879,9 +1908,6 @@ static struct dentry *proc_fd_instantiate(struct inode *dir,
out:
return error;
-out_unlock:
- spin_unlock(&files->file_lock);
- put_files_struct(files);
out_iput:
iput(inode);
goto out;
--
To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
