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@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Sage Weil <sage@xxxxxxxxxxxx>
---
fs/ceph/dir.c | 15 +++++++++++++++
fs/ceph/file.c | 8 +++++---
fs/ceph/inode.c | 4 +++-
fs/ceph/ioctl.c | 4 +++-
fs/ceph/super.h | 9 +--------
fs/ceph/xattr.c | 8 ++++++--
6 files changed, 33 insertions(+), 15 deletions(-)
diff --git a/fs/ceph/dir.c b/fs/ceph/dir.c
index 58ec879..e90315b 100644
--- a/fs/ceph/dir.c
+++ b/fs/ceph/dir.c
@@ -69,6 +69,21 @@ out_unlock:
return 0;
}
+struct inode *ceph_get_dentry_parent_inode(struct dentry *dentry)
+{
+ struct inode *inode = NULL;
+
+ if (!dentry)
+ return NULL;
+
+ spin_lock(&dentry->d_lock);
+ if (dentry->d_parent) {
+ inode = dentry->d_parent->d_inode;
+ ihold(inode);
+ }
+ spin_unlock(&dentry->d_lock);
+ return inode;
+}
/*
diff --git a/fs/ceph/file.c b/fs/ceph/file.c
index f34d47d..45fbd69 100644
--- a/fs/ceph/file.c
+++ b/fs/ceph/file.c
@@ -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);
diff --git a/fs/ceph/inode.c b/fs/ceph/inode.c
index 2717dc4..a7db56f 100644
--- a/fs/ceph/inode.c
+++ b/fs/ceph/inode.c
@@ -1562,7 +1562,7 @@ int ceph_setattr(struct dentry *dentry, struct iattr *attr)
{
struct inode *inode = dentry->d_inode;
struct ceph_inode_info *ci = ceph_inode(inode);
- struct inode *parent_inode = dentry->d_parent->d_inode;
+ struct inode *parent_inode;
const unsigned int ia_valid = attr->ia_valid;
struct ceph_mds_request *req;
struct ceph_mds_client *mdsc = ceph_sb_to_client(dentry->d_sb)->mdsc;
@@ -1745,7 +1745,9 @@ int ceph_setattr(struct dentry *dentry, struct iattr *attr)
req->r_inode_drop = release;
req->r_args.setattr.mask = cpu_to_le32(mask);
req->r_num_caps = 1;
+ parent_inode = ceph_get_dentry_parent_inode(dentry);
err = ceph_mdsc_do_request(mdsc, parent_inode, req);
+ iput(parent_inode);
}
dout("setattr %p result=%d (%s locally, %d remote)\n", inode, err,
ceph_cap_string(dirtied), mask);
diff --git a/fs/ceph/ioctl.c b/fs/ceph/ioctl.c
index a757a56..3b256b5 100644
--- a/fs/ceph/ioctl.c
+++ b/fs/ceph/ioctl.c
@@ -38,7 +38,7 @@ static long ceph_ioctl_get_layout(struct file *file, void __user *arg)
static long ceph_ioctl_set_layout(struct file *file, void __user *arg)
{
struct inode *inode = file->f_dentry->d_inode;
- struct inode *parent_inode = file->f_dentry->d_parent->d_inode;
+ struct inode *parent_inode;
struct ceph_mds_client *mdsc = ceph_sb_to_client(inode->i_sb)->mdsc;
struct ceph_mds_request *req;
struct ceph_ioctl_layout l;
@@ -87,7 +87,9 @@ static long ceph_ioctl_set_layout(struct file *file, void __user *arg)
req->r_args.setlayout.layout.fl_pg_preferred =
cpu_to_le32(l.preferred_osd);
+ parent_inode = ceph_get_dentry_parent_inode(file->f_dentry);
err = ceph_mdsc_do_request(mdsc, parent_inode, req);
+ iput(parent_inode);
ceph_mdsc_put_request(req);
return err;
}
diff --git a/fs/ceph/super.h b/fs/ceph/super.h
index c24891a..c1eb9a0 100644
--- a/fs/ceph/super.h
+++ b/fs/ceph/super.h
@@ -801,6 +801,7 @@ extern void ceph_dentry_lru_touch(struct dentry *dn);
extern void ceph_dentry_lru_del(struct dentry *dn);
extern void ceph_invalidate_dentry_lease(struct dentry *dentry);
extern unsigned ceph_dentry_hash(struct dentry *dn);
+extern struct inode *ceph_get_dentry_parent_inode(struct dentry *dentry);
/*
* our d_ops vary depending on whether the inode is live,
@@ -823,14 +824,6 @@ extern int ceph_encode_locks(struct inode *i, struct ceph_pagelist *p,
int p_locks, int f_locks);
extern int lock_to_ceph_filelock(struct file_lock *fl, struct ceph_filelock *c);
-static inline struct inode *get_dentry_parent_inode(struct dentry *dentry)
-{
- if (dentry && dentry->d_parent)
- return dentry->d_parent->d_inode;
-
- return NULL;
-}
-
/* debugfs.c */
extern int ceph_fs_debugfs_init(struct ceph_fs_client *client);
extern void ceph_fs_debugfs_cleanup(struct ceph_fs_client *client);
diff --git a/fs/ceph/xattr.c b/fs/ceph/xattr.c
index f42d730..96c6739 100644
--- a/fs/ceph/xattr.c
+++ b/fs/ceph/xattr.c
@@ -629,7 +629,7 @@ static int ceph_sync_setxattr(struct dentry *dentry, const char *name,
struct ceph_fs_client *fsc = ceph_sb_to_client(dentry->d_sb);
struct inode *inode = dentry->d_inode;
struct ceph_inode_info *ci = ceph_inode(inode);
- struct inode *parent_inode = dentry->d_parent->d_inode;
+ struct inode *parent_inode;
struct ceph_mds_request *req;
struct ceph_mds_client *mdsc = fsc->mdsc;
int err;
@@ -677,7 +677,9 @@ static int ceph_sync_setxattr(struct dentry *dentry, const char *name,
req->r_data_len = size;
dout("xattr.ver (before): %lld\n", ci->i_xattrs.version);
+ parent_inode = ceph_get_dentry_parent_inode(dentry);
err = ceph_mdsc_do_request(mdsc, parent_inode, req);
+ iput(parent_inode);
ceph_mdsc_put_request(req);
dout("xattr.ver (after): %lld\n", ci->i_xattrs.version);
@@ -788,7 +790,7 @@ static int ceph_send_removexattr(struct dentry *dentry, const char *name)
struct ceph_fs_client *fsc = ceph_sb_to_client(dentry->d_sb);
struct ceph_mds_client *mdsc = fsc->mdsc;
struct inode *inode = dentry->d_inode;
- struct inode *parent_inode = dentry->d_parent->d_inode;
+ struct inode *parent_inode;
struct ceph_mds_request *req;
int err;
@@ -802,7 +804,9 @@ static int ceph_send_removexattr(struct dentry *dentry, const char *name)
req->r_num_caps = 1;
req->r_path2 = kstrdup(name, GFP_NOFS);
+ parent_inode = ceph_get_dentry_parent_inode(dentry);
err = ceph_mdsc_do_request(mdsc, parent_inode, req);
+ iput(parent_inode);
ceph_mdsc_put_request(req);
return err;
}
--
1.7.0
--
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