[PATCH] v9fs: VFS file, dentry, and directory operations

This part of the patch contains the VFS file, dentry & directory interfaces.

Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 126 insertions, 0 deletions

diff --git a/fs/9p/vfs_dentry.c b/fs/9p/vfs_dentry.c
new file mode 100644
index 000000000000..306c96741f81
--- /dev/null
+++ b/fs/9p/vfs_dentry.c
@@ -0,0 +1,126 @@
+/*
+ *  linux/fs/9p/vfs_dentry.c
+ *
+ * This file contians vfs dentry ops for the 9P2000 protocol.
+ *
+ *  Copyright (C) 2004 by Eric Van Hensbergen <ericvh@gmail.com>
+ *  Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov>
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, write to:
+ *  Free Software Foundation
+ *  51 Franklin Street, Fifth Floor
+ *  Boston, MA  02111-1301  USA
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/errno.h>
+#include <linux/fs.h>
+#include <linux/file.h>
+#include <linux/pagemap.h>
+#include <linux/stat.h>
+#include <linux/string.h>
+#include <linux/smp_lock.h>
+#include <linux/inet.h>
+#include <linux/namei.h>
+#include <linux/idr.h>
+
+#include "debug.h"
+#include "v9fs.h"
+#include "9p.h"
+#include "v9fs_vfs.h"
+#include "conv.h"
+#include "fid.h"
+
+/**
+ * v9fs_dentry_validate - VFS dcache hook to validate cache
+ * @dentry:  dentry that is being validated
+ * @nd: path data
+ *
+ * dcache really shouldn't be used for 9P2000 as at all due to
+ * potential attached semantics to directory traversal (walk).
+ *
+ * FUTURE: look into how to use dcache to allow multi-stage
+ * walks in Plan 9 & potential for better dcache operation which
+ * would remain valid for Plan 9 semantics.  Older versions
+ * had validation via stat for those interested.  However, since
+ * stat has the same approximate overhead as walk there really
+ * is no difference.  The only improvement would be from a
+ * time-decay cache like NFS has and that undermines the
+ * synchronous nature of 9P2000.
+ *
+ */
+
+static int v9fs_dentry_validate(struct dentry *dentry, struct nameidata *nd)
+{
+        struct dentry *dc = current->fs->pwd;
+
+        dprintk(DEBUG_VFS, "dentry: %s (%p)\n", dentry->d_iname, dentry);
+        if (v9fs_fid_lookup(dentry, FID_OP)) {
+                dprintk(DEBUG_VFS, "VALID\n");
+                return 1;
+        }
+
+        while (dc != NULL) {
+                if (dc == dentry) {
+                        dprintk(DEBUG_VFS, "VALID\n");
+                        return 1;
+                }
+                if (dc == dc->d_parent)
+                        break;
+
+                dc = dc->d_parent;
+        }
+
+        dprintk(DEBUG_VFS, "INVALID\n");
+        return 0;
+}
+
+/**
+ * v9fs_dentry_release - called when dentry is going to be freed
+ * @dentry:  dentry that is being release
+ *
+ */
+
+void v9fs_dentry_release(struct dentry *dentry)
+{
+        dprintk(DEBUG_VFS, " dentry: %s (%p)\n", dentry->d_iname, dentry);
+
+        if (dentry->d_fsdata != NULL) {
+                struct list_head *fid_list = dentry->d_fsdata;
+                struct v9fs_fid *temp = NULL;
+                struct v9fs_fid *current_fid = NULL;
+                struct v9fs_fcall *fcall = NULL;
+
+                list_for_each_entry_safe(current_fid, temp, fid_list, list) {
+                        if (v9fs_t_clunk
+                            (current_fid->v9ses, current_fid->fid, &fcall))
+                                dprintk(DEBUG_ERROR, "clunk failed: %s\n",
+                                        FCALL_ERROR(fcall));
+
+                        v9fs_put_idpool(current_fid->fid,
+                                        &current_fid->v9ses->fidpool);
+
+                        kfree(fcall);
+                        v9fs_fid_destroy(current_fid);
+                }
+
+                kfree(dentry->d_fsdata);        /* free the list_head */
+        }
+}
+
+struct dentry_operations v9fs_dentry_operations = {
+        .d_revalidate = v9fs_dentry_validate,
+        .d_release = v9fs_dentry_release,
+};