@@ -97,6 +97,48 @@ static struct p9_fid *v9fs_fid_find(struct dentry *dentry, u32 uid, int any)
return ret;
}
+static int build_path_from_dentry(struct v9fs_session_info *v9ses,
+ struct dentry *dentry, char ***names)
+{
+ char **wnames;
+ int n = 0, i = 0;
+ struct dentry *ds;
+
+ read_lock(&v9ses->rename_lock);
+ for (ds = dentry; !IS_ROOT(ds); ds = ds->d_parent)
+ n++;
+
+ wnames = kmalloc(sizeof(char *) * n, GFP_KERNEL);
+ if (!wnames) {
+ n = 0;
+ goto err_out;
+ }
+ for (ds = dentry, i = (n-1); i >= 0; i--, ds = ds->d_parent) {
+ wnames[i] = kmalloc(strlen(ds->d_name.name) + 1, GFP_KERNEL);
+ if (!wnames[i])
+ goto err_out;
+
+ strcpy(wnames[i], ds->d_name.name);
+ }
+ *names = wnames;
+ read_unlock(&v9ses->rename_lock);
+ return n;
+err_out:
+ read_unlock(&v9ses->rename_lock);
+ for (; i < n; i++)
+ kfree(wnames[i]);
+ kfree(wnames);
+ return -ENOMEM;
+}
+
+static void kfree_wnames(char **wnames, int n)
+{
+ int i;
+ for (i = 0; i < n; i++)
+ kfree(wnames[i]);
+ kfree(wnames);
+}
+
/**
* v9fs_fid_lookup - lookup for a fid, try to walk if not found
* @dentry: dentry to look for fid in
@@ -112,7 +154,7 @@ struct p9_fid *v9fs_fid_lookup(struct dentry *dentry)
int i, n, l, clone, any, access;
u32 uid;
struct p9_fid *fid, *old_fid = NULL;
- struct dentry *d, *ds;
+ struct dentry *ds;
struct v9fs_session_info *v9ses;
char **wnames, *uname;
@@ -139,46 +181,62 @@ 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++;
-
- fid = v9fs_fid_find(ds, uid, any);
- if (!fid) { /* the user is not attached to the fs yet */
- if (access == V9FS_ACCESS_SINGLE)
- return ERR_PTR(-EPERM);
-
- if (v9fs_proto_dotu(v9ses) ||
- v9fs_proto_dotl(v9ses))
+ if (fid) {
+ /*
+ * Found the parent fid do a lookup with that.
+ * We want to do the walk without holding rename_lock
+ */
+ char *dentry_name;
+ dentry_name = kmalloc(strlen(dentry->d_name.name) + 1,
+ GFP_KERNEL);
+ if (dentry_name) {
+ strcpy(dentry_name, dentry->d_name.name);
+ read_unlock(&v9ses->rename_lock);
+ fid = p9_client_walk(fid, 1, (char **)&dentry_name, 1);
+ kfree(dentry_name);
+ goto dentry_out;
+ } else {
+ read_unlock(&v9ses->rename_lock);
+ return ERR_PTR(-ENOMEM);
+ }
+ }
+ read_unlock(&v9ses->rename_lock);
+ /* start from the root and try to do a lookup */
+ fid = v9fs_fid_find(dentry->d_sb->s_root, uid, any);
+ if (!fid) {
+ /* the user is not attached to the fs yet */
+ if (access == V9FS_ACCESS_SINGLE)
+ return ERR_PTR(-EPERM);
+
+ if (v9fs_proto_dotu(v9ses) || v9fs_proto_dotl(v9ses))
uname = NULL;
- else
- uname = v9ses->uname;
-
- fid = p9_client_attach(v9ses->clnt, NULL, uname, uid,
- v9ses->aname);
+ else
+ uname = v9ses->uname;
- if (IS_ERR(fid))
- return fid;
-
- v9fs_fid_add(ds, fid);
- }
- } else /* walk from the parent */
- n = 1;
+ fid = p9_client_attach(v9ses->clnt, NULL, uname, uid,
+ v9ses->aname);
+ if (IS_ERR(fid))
+ return fid;
- if (ds == dentry)
+ v9fs_fid_add(dentry->d_sb->s_root, fid);
+ }
+ /* If we are root just return the fid */
+ if (dentry->d_sb->s_root == dentry)
return fid;
- wnames = kmalloc(sizeof(char *) * n, GFP_KERNEL);
- if (!wnames)
- return ERR_PTR(-ENOMEM);
-
- for (d = dentry, i = (n-1); i >= 0; i--, d = d->d_parent)
- wnames[i] = (char *) d->d_name.name;
-
+ n = build_path_from_dentry(v9ses, dentry, &wnames);
+ if (n < 0) {
+ fid = ERR_PTR(n);
+ goto err_out;
+ }
clone = 1;
i = 0;
while (i < n) {
@@ -193,16 +251,18 @@ struct p9_fid *v9fs_fid_lookup(struct dentry *dentry)
*/
p9_client_clunk(old_fid);
}
- kfree(wnames);
- return fid;
+ kfree_wnames(wnames, n);
+ goto err_out;
}
old_fid = fid;
i += l;
clone = 0;
}
+ kfree_wnames(wnames, n);
- kfree(wnames);
+dentry_out:
v9fs_fid_add(dentry, fid);
+err_out:
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 *,
@@ -750,6 +750,7 @@ 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);
@@ -856,28 +857,34 @@ v9fs_vfs_rename(struct inode *old_dir, struct dentry *old_dentry,
retval = PTR_ERR(newdirfid);
goto clunk_olddir;
}
-
if (v9fs_proto_dotl(v9ses)) {
retval = p9_client_rename(oldfid, newdirfid,
(char *) new_dentry->d_name.name);
if (retval != -ENOSYS)
goto clunk_newdir;
}
+ if (old_dentry->d_parent != new_dentry->d_parent) {
+ /*
+ * 9P .u can only handle file rename in the same directory
+ */
- /* 9P can only handle file rename in the same directory */
- if (memcmp(&olddirfid->qid, &newdirfid->qid, sizeof(newdirfid->qid))) {
P9_DPRINTK(P9_DEBUG_ERROR,
"old dir and new dir are different\n");
retval = -EXDEV;
goto clunk_newdir;
}
-
v9fs_blank_wstat(&wstat);
wstat.muid = v9ses->uname;
wstat.name = (char *) new_dentry->d_name.name;
retval = p9_client_wstat(oldfid, &wstat);
clunk_newdir:
+ if (!retval) {
+ write_lock(&v9ses->rename_lock);
+ /* successful rename */
+ d_move(old_dentry, new_dentry);
+ write_unlock(&v9ses->rename_lock);
+ }
p9_client_clunk(newdirfid);
clunk_olddir:
@@ -285,4 +285,5 @@ 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,
};