From d45ea86792db9679ed010b2c3df3db32b2ce5bde Mon Sep 17 00:00:00 2001 From: Miklos Szeredi Date: Mon, 21 May 2012 17:30:09 +0200 Subject: vfs: make follow_link check RCU safe This will allow this code to be used in RCU mode. Signed-off-by: Miklos Szeredi Signed-off-by: Al Viro --- fs/namei.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) diff --git a/fs/namei.c b/fs/namei.c index 41445e7fd339..c6b996817bb3 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -2201,6 +2201,7 @@ static struct file *do_last(struct nameidata *nd, struct path *path, int acc_mode = op->acc_mode; struct file *filp; struct inode *inode; + int symlink_ok = 0; int error; nd->flags &= ~LOOKUP_PARENT; @@ -2232,7 +2233,6 @@ static struct file *do_last(struct nameidata *nd, struct path *path, } if (!(open_flag & O_CREAT)) { - int symlink_ok = 0; if (nd->last.name[nd->last.len]) nd->flags |= LOOKUP_FOLLOW | LOOKUP_DIRECTORY; if (open_flag & O_PATH && !(nd->flags & LOOKUP_FOLLOW)) @@ -2364,8 +2364,16 @@ static struct file *do_last(struct nameidata *nd, struct path *path, if (!inode) goto exit_dput; - if (inode->i_op->follow_link) + if (should_follow_link(inode, !symlink_ok)) { + if (nd->flags & LOOKUP_RCU) { + if (unlikely(unlazy_walk(nd, path->dentry))) { + error = -ECHILD; + goto exit; + } + } + BUG_ON(inode != path->dentry->d_inode); return NULL; + } path_to_nameidata(path, nd); nd->inode = inode; -- cgit v1.2.3-59-g8ed1b