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authorAl Viro <viro@zeniv.linux.org.uk>2019-10-29 16:50:19 +0300
committerIlya Dryomov <idryomov@gmail.com>2019-10-30 00:29:54 +0300
commitaa8dd816732b2bab28c54bc4d2ccf3fc8a6e0892 (patch)
tree0805d90f6214b72791f9ca0cd12cc85b1dd6d3fa /fs
parentea60ed6fcf29eebc78f2ce91491e6309ee005a01 (diff)
downloadlinux-aa8dd816732b2bab28c54bc4d2ccf3fc8a6e0892.tar.xz
ceph: fix RCU case handling in ceph_d_revalidate()
For RCU case ->d_revalidate() is called with rcu_read_lock() and without pinning the dentry passed to it. Which means that it can't rely upon ->d_inode remaining stable; that's the reason for d_inode_rcu(), actually. Make sure we don't reload ->d_inode there. Cc: stable@vger.kernel.org Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Diffstat (limited to 'fs')
-rw-r--r--fs/ceph/dir.c15
1 files changed, 8 insertions, 7 deletions
diff --git a/fs/ceph/dir.c b/fs/ceph/dir.c
index 4ca0b8ff9a72..d17a789fd856 100644
--- a/fs/ceph/dir.c
+++ b/fs/ceph/dir.c
@@ -1553,36 +1553,37 @@ static int ceph_d_revalidate(struct dentry *dentry, unsigned int flags)
{
int valid = 0;
struct dentry *parent;
- struct inode *dir;
+ struct inode *dir, *inode;
if (flags & LOOKUP_RCU) {
parent = READ_ONCE(dentry->d_parent);
dir = d_inode_rcu(parent);
if (!dir)
return -ECHILD;
+ inode = d_inode_rcu(dentry);
} else {
parent = dget_parent(dentry);
dir = d_inode(parent);
+ inode = d_inode(dentry);
}
dout("d_revalidate %p '%pd' inode %p offset %lld\n", dentry,
- dentry, d_inode(dentry), ceph_dentry(dentry)->offset);
+ dentry, inode, ceph_dentry(dentry)->offset);
/* always trust cached snapped dentries, snapdir dentry */
if (ceph_snap(dir) != CEPH_NOSNAP) {
dout("d_revalidate %p '%pd' inode %p is SNAPPED\n", dentry,
- dentry, d_inode(dentry));
+ dentry, inode);
valid = 1;
- } else if (d_really_is_positive(dentry) &&
- ceph_snap(d_inode(dentry)) == CEPH_SNAPDIR) {
+ } else if (inode && ceph_snap(inode) == CEPH_SNAPDIR) {
valid = 1;
} else {
valid = dentry_lease_is_valid(dentry, flags);
if (valid == -ECHILD)
return valid;
if (valid || dir_lease_is_valid(dir, dentry)) {
- if (d_really_is_positive(dentry))
- valid = ceph_is_any_caps(d_inode(dentry));
+ if (inode)
+ valid = ceph_is_any_caps(inode);
else
valid = 1;
}