@@ -139,14 +139,19 @@ struct p9_fid *v9fs_fid_lookup(struct dentry *dentry)
fid = v9fs_fid_find(dentry, uid, any);
if (fid)
return fid;
-
+ /*
+ * we don't have a matching fid. To do a TWALK we need
+ * parent fid. We need to prevent rename when we want to
+ * look at the parent.
+ */
+ read_lock(&v9ses->rename_lock);
ds = dentry->d_parent;
fid = v9fs_fid_find(ds, uid, any);
if (!fid) { /* walk from the root */
n = 0;
for (ds = dentry; !IS_ROOT(ds); ds = ds->d_parent)
n++;
-
+ read_unlock(&v9ses->rename_lock);
fid = v9fs_fid_find(ds, uid, any);
if (!fid) { /* the user is not attached to the fs yet */
if (access == V9FS_ACCESS_SINGLE)
@@ -165,9 +170,11 @@ struct p9_fid *v9fs_fid_lookup(struct dentry *dentry)
v9fs_fid_add(ds, fid);
}
- } else /* walk from the parent */
+ } else {
+ /* walk from the parent */
n = 1;
-
+ read_unlock(&v9ses->rename_lock);
+ }
if (ds == dentry)
return fid;
@@ -175,8 +182,10 @@ struct p9_fid *v9fs_fid_lookup(struct dentry *dentry)
if (!wnames)
return ERR_PTR(-ENOMEM);
+ read_lock(&v9ses->rename_lock);
for (d = dentry, i = (n-1); i >= 0; i--, d = d->d_parent)
wnames[i] = (char *) d->d_name.name;
+ read_unlock(&v9ses->rename_lock);
clone = 1;
i = 0;
@@ -199,7 +208,6 @@ struct p9_fid *v9fs_fid_lookup(struct dentry *dentry)
i += l;
clone = 0;
}
-
kfree(wnames);
v9fs_fid_add(dentry, fid);
return fid;
@@ -237,6 +237,7 @@ struct p9_fid *v9fs_session_init(struct v9fs_session_info *v9ses,
__putname(v9ses->uname);
return ERR_PTR(-ENOMEM);
}
+ rwlock_init(&v9ses->rename_lock);
rc = bdi_setup_and_register(&v9ses->bdi, "9p", BDI_CAP_MAP_COPY);
if (rc) {
@@ -104,6 +104,7 @@ struct v9fs_session_info {
struct p9_client *clnt; /* 9p client */
struct list_head slist; /* list of sessions registered with v9fs */
struct backing_dev_info bdi;
+ rwlock_t rename_lock;
};
struct p9_fid *v9fs_session_init(struct v9fs_session_info *, const char *,
@@ -678,6 +678,7 @@ static struct dentry *v9fs_vfs_lookup(struct inode *dir, struct dentry *dentry,
sb = dir->i_sb;
v9ses = v9fs_inode2v9ses(dir);
+ /* We can walk d_parent because we hold the dir->i_mutex */
dfid = v9fs_fid_lookup(dentry->d_parent);
if (IS_ERR(dfid))
return ERR_CAST(dfid);
@@ -763,7 +764,7 @@ v9fs_vfs_rename(struct inode *old_dir, struct dentry *old_dentry,
struct p9_fid *olddirfid;
struct p9_fid *newdirfid;
struct p9_wstat wstat;
- int retval;
+ int retval, cross_dir_rename;
P9_DPRINTK(P9_DEBUG_VFS, "\n");
retval = 0;
@@ -784,7 +785,7 @@ v9fs_vfs_rename(struct inode *old_dir, struct dentry *old_dentry,
retval = PTR_ERR(newdirfid);
goto clunk_olddir;
}
-
+ cross_dir_rename = (old_dentry->d_parent != new_dentry->d_parent);
if (v9fs_proto_dotl(v9ses)) {
retval = p9_client_rename(oldfid, newdirfid,
(char *) new_dentry->d_name.name);
@@ -806,6 +807,11 @@ v9fs_vfs_rename(struct inode *old_dir, struct dentry *old_dentry,
retval = p9_client_wstat(oldfid, &wstat);
clunk_newdir:
+ if (cross_dir_rename)
+ write_lock(&v9ses->rename_lock);
+ d_move(old_dentry, new_dentry);
+ if (cross_dir_rename)
+ write_unlock(&v9ses->rename_lock);
p9_client_clunk(newdirfid);
clunk_olddir:
@@ -278,4 +278,5 @@ struct file_system_type v9fs_fs_type = {
.get_sb = v9fs_get_sb,
.kill_sb = v9fs_kill_super,
.owner = THIS_MODULE,
+ .fs_flags = FS_RENAME_DOES_D_MOVE,
};