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ceph: protect access to d_parent

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d_parent is protected by d_lock: use it when looking up a dentry's parent
directory inode.  Also take a reference and drop it in the caller to avoid
a use-after-free.

Reported-by: Al Viro <viro@ZenIV.linux.org.uk>
Reviewed-by: Yehuda Sadeh <yehuda@hq.newdream.net>
Signed-off-by: Sage Weil <sage@newdream.net>
This commit is contained in:
Sage Weil
2011-07-26 11:30:29 -07:00
parent 48d0cbd124
commit 5f21c96dd5
6 changed files with 33 additions and 15 deletions
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8
fs/ceph/file.c
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@@ -122,7 +122,7 @@ int ceph_open(struct inode *inode, struct file *file)
struct ceph_mds_client *mdsc = fsc->mdsc;
struct ceph_mds_request *req;
struct ceph_file_info *cf = file->private_data;
struct inode *parent_inode = file->f_dentry->d_parent->d_inode;
struct inode *parent_inode = NULL;
int err;
int flags, fmode, wanted;
@@ -194,8 +194,10 @@ int ceph_open(struct inode *inode, struct file *file)
req->r_inode = inode;
ihold(inode);
req->r_num_caps = 1;
err = ceph_mdsc_do_request(mdsc, (flags & (O_CREAT|O_TRUNC)) ?
parent_inode : NULL, req);
if (flags & (O_CREAT|O_TRUNC))
parent_inode = ceph_get_dentry_parent_inode(file->f_dentry);
err = ceph_mdsc_do_request(mdsc, parent_inode, req);
iput(parent_inode);
if (!err)
err = ceph_init_file(inode, file, req->r_fmode);
ceph_mdsc_put_request(req);