[PATCH 13/23] vfs: Teach ioctl to use file_hotplug_lock

Eric W. Biederman
2009-06-01T21:54:59Z

From: Eric W. Biederman <ebiederm@maxwell.arastra.com>

Signed-off-by: Eric W. Biederman <ebiederm@aristanetworks.com>
---
fs/compat_ioctl.c | 14 ++++++++++----
fs/ioctl.c | 8 +++++++-
2 files changed, 17 insertions(+), 5 deletions(-)

diff --git a/fs/compat_ioctl.c b/fs/compat_ioctl.c
index b83f6bc..fa654c5 100644
--- a/fs/compat_ioctl.c
+++ b/fs/compat_ioctl.c
@@ -2796,10 +2796,14 @@ asmlinkage long compat_sys_ioctl(unsigned int fd, unsigned int cmd,
if (!filp)
goto out;

+ error = -EIO;
+ if (!file_hotplug_read_trylock(filp))
+ goto out_fput;
+
/* RED-PEN how should LSM module know it's handling 32bit? */
error = security_file_ioctl(filp, cmd, arg);
if (error)
- goto out_fput;
+ goto out_unlock;

/*
* To allow the compat_ioctl handlers to be self contained
@@ -2825,7 +2829,7 @@ asmlinkage long compat_sys_ioctl(unsigned int fd, unsigned int cmd,
if (filp->f_op && filp->f_op->compat_ioctl) {
error = filp->f_op->compat_ioctl(filp, cmd, arg);
if (error != -ENOIOCTLCMD)
- goto out_fput;
+ goto out_unlock;
}

if (!filp->f_op ||
@@ -2853,18 +2857,20 @@ asmlinkage long compat_sys_ioctl(unsigned int fd, unsigned int cmd,
error = -EINVAL;
}

- goto out_fput;
+ goto out_unlock;

found_handler:
if (t->handler) {
lock_kernel();
error = t->handler(fd, cmd, arg, filp);
unlock_kernel();
- goto out_fput;
+ goto out_unlock;
}

do_ioctl:
error = do_vfs_ioctl(filp, fd, cmd, arg);
+ out_unlock:
+ file_hotplug_read_unlock(filp);
out_fput:
fput_light(filp, fput_needed);
out:
diff --git a/fs/ioctl.c b/fs/ioctl.c
index 82d9c42..2dad7ba 100644
--- a/fs/ioctl.c
+++ b/fs/ioctl.c
@@ -577,11 +577,17 @@ SYSCALL_DEFINE3(ioctl, unsigned int, fd, unsigned int, cmd, unsigned long, arg)
if (!filp)
goto out;

+ error = -EIO;
+ if (!file_hotplug_read_trylock(filp))
+ goto out_fput;
+
error = security_file_ioctl(filp, cmd, arg);
if (error)
- goto out_fput;
+ goto out_unlock;

error = do_vfs_ioctl(filp, fd, cmd, arg);
+ out_unlock:
+ file_hotplug_read_unlock(filp);
out_fput:
fput_light(filp, fput_needed);
out:
--
1.6.3.1.54.g99dd.dirty