[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>

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,
+};

fs/9p/vfs_dir.c

@@ -0,0 +1,226 @@
+/*
+ * linux/fs/9p/vfs_dir.c
+ *
+ * This file contains vfs directory 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/stat.h>
+#include <linux/string.h>
+#include <linux/smp_lock.h>
+#include <linux/inet.h>
+#include <linux/idr.h>
+
+#include "debug.h"
+#include "v9fs.h"
+#include "9p.h"
+#include "v9fs_vfs.h"
+#include "conv.h"
+#include "fid.h"
+
+/**
+ * dt_type - return file type
+ * @mistat: mistat structure
+ *
+ */
+
+static inline int dt_type(struct v9fs_stat *mistat)
+{
+	unsigned long perm = mistat->mode;
+	int rettype = DT_REG;
+
+	if (perm & V9FS_DMDIR)
+		rettype = DT_DIR;
+	if (perm & V9FS_DMSYMLINK)
+		rettype = DT_LNK;
+
+	return rettype;
+}
+
+/**
+ * v9fs_dir_readdir - read a directory
+ * @filep: opened file structure
+ * @dirent: directory structure ???
+ * @filldir: function to populate directory structure ???
+ *
+ */
+
+static int v9fs_dir_readdir(struct file *filp, void *dirent, filldir_t filldir)
+{
+	struct v9fs_fcall *fcall = NULL;
+	struct inode *inode = filp->f_dentry->d_inode;
+	struct v9fs_session_info *v9ses = v9fs_inode2v9ses(inode);
+	struct v9fs_fid *file = filp->private_data;
+	unsigned int i, n;
+	int fid = -1;
+	int ret = 0;
+	struct v9fs_stat *mi = NULL;
+	int over = 0;
+
+	dprintk(DEBUG_VFS, "name %s\n", filp->f_dentry->d_name.name);
+
+	fid = file->fid;
+
+	mi = kmalloc(v9ses->maxdata, GFP_KERNEL);
+	if (!mi)
+		return -ENOMEM;
+
+	if (file->rdir_fcall && (filp->f_pos != file->rdir_pos)) {
+		kfree(file->rdir_fcall);
+		file->rdir_fcall = NULL;
+	}
+
+	if (file->rdir_fcall) {
+		n = file->rdir_fcall->params.rread.count;
+		i = file->rdir_fpos;
+		while (i < n) {
+			int s = v9fs_deserialize_stat(v9ses,
+				  file->rdir_fcall->params.rread.data + i,
+			          n - i, mi, v9ses->maxdata);
+
+			if (s == 0) {
+				dprintk(DEBUG_ERROR,
+					"error while deserializing mistat\n");
+				ret = -EIO;
+				goto FreeStructs;
+			}
+
+			over = filldir(dirent, mi->name, strlen(mi->name),
+				    filp->f_pos, v9fs_qid2ino(&mi->qid),
+				    dt_type(mi));
+
+			if (over) {
+				file->rdir_fpos = i;
+				file->rdir_pos = filp->f_pos;
+				break;
+			}
+
+			i += s;
+			filp->f_pos += s;
+		}
+
+		if (!over) {
+			kfree(file->rdir_fcall);
+			file->rdir_fcall = NULL;
+		}
+	}
+
+	while (!over) {
+		ret = v9fs_t_read(v9ses, fid, filp->f_pos,
+					    v9ses->maxdata-V9FS_IOHDRSZ, &fcall);
+		if (ret < 0) {
+			dprintk(DEBUG_ERROR, "error while reading: %d: %p\n",
+				ret, fcall);
+			goto FreeStructs;
+		} else if (ret == 0)
+			break;
+
+		n = ret;
+		i = 0;
+		while (i < n) {
+			int s = v9fs_deserialize_stat(v9ses,
+			          fcall->params.rread.data + i, n - i, mi,
+			          v9ses->maxdata);
+
+			if (s == 0) {
+				dprintk(DEBUG_ERROR,
+					"error while deserializing mistat\n");
+				return -EIO;
+			}
+
+			over = filldir(dirent, mi->name, strlen(mi->name),
+				    filp->f_pos, v9fs_qid2ino(&mi->qid),
+				    dt_type(mi));
+
+			if (over) {
+				file->rdir_fcall = fcall;
+				file->rdir_fpos = i;
+				file->rdir_pos = filp->f_pos;
+				fcall = NULL;
+				break;
+			}
+
+			i += s;
+			filp->f_pos += s;
+		}
+
+		kfree(fcall);
+	}
+
+      FreeStructs:
+	kfree(fcall);
+	kfree(mi);
+	return ret;
+}
+
+/**
+ * v9fs_dir_release - close a directory
+ * @inode: inode of the directory
+ * @filp: file pointer to a directory
+ *
+ */
+
+int v9fs_dir_release(struct inode *inode, struct file *filp)
+{
+	struct v9fs_session_info *v9ses = v9fs_inode2v9ses(inode);
+	struct v9fs_fid *fid = filp->private_data;
+	int fidnum = -1;
+
+	dprintk(DEBUG_VFS, "inode: %p filp: %p fid: %d\n", inode, filp,
+		fid->fid);
+	fidnum = fid->fid;
+
+	filemap_fdatawrite(inode->i_mapping);
+	filemap_fdatawait(inode->i_mapping);
+
+	if (fidnum >= 0) {
+		fid->fidopen--;
+		dprintk(DEBUG_VFS, "fidopen: %d v9f->fid: %d\n", fid->fidopen,
+			fid->fid);
+
+		if (fid->fidopen == 0) {
+			if (v9fs_t_clunk(v9ses, fidnum, NULL))
+				dprintk(DEBUG_ERROR, "clunk failed\n");
+
+			v9fs_put_idpool(fid->fid, &v9ses->fidpool);
+		}
+
+		kfree(fid->rdir_fcall);
+
+		filp->private_data = NULL;
+		v9fs_fid_destroy(fid);
+	}
+
+	d_drop(filp->f_dentry);
+	return 0;
+}
+
+struct file_operations v9fs_dir_operations = {
+	.read = generic_read_dir,
+	.readdir = v9fs_dir_readdir,
+	.open = v9fs_file_open,
+	.release = v9fs_dir_release,
+};