From d70ef97baf048412c395bb5d65791d8fe133a52b Mon Sep 17 00:00:00 2001 From: Pavel Emelyanov Date: Mon, 31 Oct 2011 17:10:04 -0700 Subject: fs/pipe.c: add ->statfs callback for pipefs Currently a statfs on a pipe's /proc//fd/ link returns -ENOSYS. Wire pipfs up so that the statfs succeeds. This is required by checkpoint-restart in the userspace to make it possible to distinguish pipes from fifos. When we dump information about task's open files we use the /proc/pid/fd directoy's symlinks and the fact that opening any of them gives us exactly the same dentry->inode pair as the original process has. Now if a task we're dumping has opened pipe and fifo we need to detect this and act accordingly. Knowing that an fd with type S_ISFIFO resides on a pipefs is the most precise way. Signed-off-by: Pavel Emelyanov Reviewed-by: Tejun Heo Acked-by: Serge Hallyn Signed-off-by: Cyrill Gorcunov Cc: Al Viro Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/pipe.c | 1 + 1 file changed, 1 insertion(+) (limited to 'fs/pipe.c') diff --git a/fs/pipe.c b/fs/pipe.c index 0e0be1dc0f8e..4065f07366b3 100644 --- a/fs/pipe.c +++ b/fs/pipe.c @@ -1254,6 +1254,7 @@ out: static const struct super_operations pipefs_ops = { .destroy_inode = free_inode_nonrcu, + .statfs = simple_statfs, }; /* -- cgit v1.2.3-55-g7522