mm: fix refcounting in swapon

Grab a reference to bdev before calling blkdev_get(), which expects
the refcount to be already incremented and either returns success or
decrements the refcount and returns an error.

The bug was introduced by e525fd89 (block: make blkdev_get/put()
handle exclusive access), which didn't take into account this behavior
of blkdev_get().

Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Miklos Szeredi 2011-02-24 15:49:53 +01:00 committed by Linus Torvalds
parent 3c522cedb5
commit 8074b26f67

View File

@ -1940,7 +1940,7 @@ SYSCALL_DEFINE2(swapon, const char __user *, specialfile, int, swap_flags)
error = -EINVAL;
if (S_ISBLK(inode->i_mode)) {
bdev = I_BDEV(inode);
bdev = bdgrab(I_BDEV(inode));
error = blkdev_get(bdev, FMODE_READ | FMODE_WRITE | FMODE_EXCL,
sys_swapon);
if (error < 0) {