From f3c7691e8d30d88899b514675c7c86d19057b5fd Mon Sep 17 00:00:00 2001 From: "J. Bruce Fields" Date: Wed, 21 Sep 2011 10:58:13 -0400 Subject: leases: fix write-open/read-lease race In setlease, we use i_writecount to decide whether we can give out a read lease. In open, we break leases before incrementing i_writecount. There is therefore a window between the break lease and the i_writecount increment when setlease could add a new read lease. This would leave us with a simultaneous write open and read lease, which shouldn't happen. Signed-off-by: J. Bruce Fields Signed-off-by: Christoph Hellwig diff --git a/fs/namei.c b/fs/namei.c index 9061157..7657be4 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -2035,10 +2035,7 @@ static int may_open(struct path *path, int acc_mode, int flag) if (flag & O_NOATIME && !inode_owner_or_capable(inode)) return -EPERM; - /* - * Ensure there are no outstanding leases on the file. - */ - return break_lease(inode, flag); + return 0; } static int handle_truncate(struct file *filp) diff --git a/fs/open.c b/fs/open.c index f711921..22c41b5 100644 --- a/fs/open.c +++ b/fs/open.c @@ -685,6 +685,10 @@ static struct file *__dentry_open(struct dentry *dentry, struct vfsmount *mnt, if (error) goto cleanup_all; + error = break_lease(inode, f->f_flags); + if (error) + goto cleanup_all; + if (!open && f->f_op) open = f->f_op->open; if (open) { -- cgit v0.10.2