tree 3ced44a52b09e6414501f686a12f77ca09bbd067
parent 93fa58cb831337fdf5d36b3b913441100a484dae
author Eric Van Hensbergen <[EMAIL PROTECTED]> Sat, 10 Sep 2005 03:04:18 -0700
committer Linus Torvalds <[EMAIL PROTECTED]> Sat, 10 Sep 2005 03:57:56 -0700

[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 <[EMAIL PROTECTED]>
Signed-off-by: Andrew Morton <[EMAIL PROTECTED]>
Signed-off-by: Linus Torvalds <[EMAIL PROTECTED]>

 fs/9p/vfs_dentry.c |  126 ++++++++++++++++
 fs/9p/vfs_dir.c    |  226 +++++++++++++++++++++++++++++
 fs/9p/vfs_file.c   |  401 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 753 insertions(+)

diff --git a/fs/9p/vfs_dentry.c b/fs/9p/vfs_dentry.c
new file mode 100644
--- /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 <[EMAIL PROTECTED]>
+ *  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,
+};
diff --git a/fs/9p/vfs_dir.c b/fs/9p/vfs_dir.c
new file mode 100644
--- /dev/null
+++ b/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 <[EMAIL PROTECTED]>
+ *  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,
+};
diff --git a/fs/9p/vfs_file.c b/fs/9p/vfs_file.c
new file mode 100644
--- /dev/null
+++ b/fs/9p/vfs_file.c
@@ -0,0 +1,401 @@
+/*
+ *  linux/fs/9p/vfs_file.c
+ *
+ * This file contians vfs file ops for 9P2000.
+ *
+ *  Copyright (C) 2004 by Eric Van Hensbergen <[EMAIL PROTECTED]>
+ *  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/version.h>
+#include <linux/list.h>
+#include <asm/uaccess.h>
+#include <linux/idr.h>
+
+#include "debug.h"
+#include "v9fs.h"
+#include "9p.h"
+#include "v9fs_vfs.h"
+#include "fid.h"
+
+/**
+ * v9fs_file_open - open a file (or directory)
+ * @inode: inode to be opened
+ * @file: file being opened
+ *
+ */
+
+int v9fs_file_open(struct inode *inode, struct file *file)
+{
+       struct v9fs_session_info *v9ses = v9fs_inode2v9ses(inode);
+       struct v9fs_fid *v9fid = v9fs_fid_lookup(file->f_dentry, FID_WALK);
+       struct v9fs_fid *v9newfid = NULL;
+       struct v9fs_fcall *fcall = NULL;
+       int open_mode = 0;
+       unsigned int iounit = 0;
+       int newfid = -1;
+       long result = -1;
+
+       dprintk(DEBUG_VFS, "inode: %p file: %p v9fid= %p\n", inode, file,
+               v9fid);
+
+       if (!v9fid) {
+               struct dentry *dentry = file->f_dentry;
+               dprintk(DEBUG_ERROR, "Couldn't resolve fid from dentry\n");
+
+               /* XXX - some duplication from lookup, generalize later */
+               /* basically vfs_lookup is too heavy weight */
+               v9fid = v9fs_fid_lookup(file->f_dentry, FID_OP);
+               if (!v9fid)
+                       return -EBADF;
+
+               v9fid = v9fs_fid_lookup(dentry->d_parent, FID_WALK);
+               if (!v9fid)
+                       return -EBADF;
+
+               newfid = v9fs_get_idpool(&v9ses->fidpool);
+               if (newfid < 0) {
+                       eprintk(KERN_WARNING, "newfid fails!\n");
+                       return -ENOSPC;
+               }
+
+               result =
+                   v9fs_t_walk(v9ses, v9fid->fid, newfid,
+                               (char *)file->f_dentry->d_name.name, NULL);
+               if (result < 0) {
+                       v9fs_put_idpool(newfid, &v9ses->fidpool);
+                       dprintk(DEBUG_ERROR, "rewalk didn't work\n");
+                       return -EBADF;
+               }
+
+               v9fid = v9fs_fid_create(dentry);
+               if (v9fid == NULL) {
+                       dprintk(DEBUG_ERROR, "couldn't insert\n");
+                       return -ENOMEM;
+               }
+               v9fid->fid = newfid;
+       }
+
+       if (v9fid->fidcreate) {
+               /* create case */
+               newfid = v9fid->fid;
+               iounit = v9fid->iounit;
+               v9fid->fidcreate = 0;
+       } else {
+               if (!S_ISDIR(inode->i_mode))
+                       newfid = v9fid->fid;
+               else {
+                       newfid = v9fs_get_idpool(&v9ses->fidpool);
+                       if (newfid < 0) {
+                               eprintk(KERN_WARNING, "allocation failed\n");
+                               return -ENOSPC;
+                       }
+                       /* This would be a somewhat critical clone */
+                       result =
+                           v9fs_t_walk(v9ses, v9fid->fid, newfid, NULL,
+                                       &fcall);
+                       if (result < 0) {
+                               dprintk(DEBUG_ERROR, "clone error: %s\n",
+                                       FCALL_ERROR(fcall));
+                               kfree(fcall);
+                               return result;
+                       }
+
+                       v9newfid = v9fs_fid_create(file->f_dentry);
+                       v9newfid->fid = newfid;
+                       v9newfid->qid = v9fid->qid;
+                       v9newfid->iounit = v9fid->iounit;
+                       v9newfid->fidopen = 0;
+                       v9newfid->fidclunked = 0;
+                       v9newfid->v9ses = v9ses;
+                       v9fid = v9newfid;
+                       kfree(fcall);
+               }
+
+               /* TODO: do special things for O_EXCL, O_NOFOLLOW, O_SYNC */
+               /* translate open mode appropriately */
+               open_mode = file->f_flags & 0x3;
+
+               if (file->f_flags & O_EXCL)
+                       open_mode |= V9FS_OEXCL;
+
+               if (v9ses->extended) {
+                       if (file->f_flags & O_TRUNC)
+                               open_mode |= V9FS_OTRUNC;
+
+                       if (file->f_flags & O_APPEND)
+                               open_mode |= V9FS_OAPPEND;
+               }
+
+               result = v9fs_t_open(v9ses, newfid, open_mode, &fcall);
+               if (result < 0) {
+                       dprintk(DEBUG_ERROR,
+                               "open failed, open_mode 0x%x: %s\n", open_mode,
+                               FCALL_ERROR(fcall));
+                       kfree(fcall);
+                       return result;
+               }
+
+               iounit = fcall->params.ropen.iounit;
+               kfree(fcall);
+       }
+
+
+       file->private_data = v9fid;
+
+       v9fid->rdir_pos = 0;
+       v9fid->rdir_fcall = NULL;
+       v9fid->fidopen = 1;
+       v9fid->filp = file;
+       v9fid->iounit = iounit;
+
+       return 0;
+}
+
+/**
+ * v9fs_file_lock - lock a file (or directory)
+ * @inode: inode to be opened
+ * @file: file being opened
+ *
+ * XXX - this looks like a local only lock, we should extend into 9P
+ *       by using open exclusive
+ */
+
+static int v9fs_file_lock(struct file *filp, int cmd, struct file_lock *fl)
+{
+       int res = 0;
+       struct inode *inode = filp->f_dentry->d_inode;
+
+       dprintk(DEBUG_VFS, "filp: %p lock: %p\n", filp, fl);
+
+       /* No mandatory locks */
+       if ((inode->i_mode & (S_ISGID | S_IXGRP)) == S_ISGID)
+               return -ENOLCK;
+
+       if ((IS_SETLK(cmd) || IS_SETLKW(cmd)) && fl->fl_type != F_UNLCK) {
+               filemap_fdatawrite(inode->i_mapping);
+               filemap_fdatawait(inode->i_mapping);
+               invalidate_inode_pages(&inode->i_data);
+       }
+
+       return res;
+}
+
+/**
+ * v9fs_read - read from a file (internal)
+ * @filep: file pointer to read
+ * @data: data buffer to read data into
+ * @count: size of buffer
+ * @offset: offset at which to read data
+ *
+ */
+
+static ssize_t
+v9fs_read(struct file *filp, char *buffer, size_t count, loff_t * offset)
+{
+       struct inode *inode = filp->f_dentry->d_inode;
+       struct v9fs_session_info *v9ses = v9fs_inode2v9ses(inode);
+       struct v9fs_fid *v9f = filp->private_data;
+       struct v9fs_fcall *fcall = NULL;
+       int fid = v9f->fid;
+       int rsize = 0;
+       int result = 0;
+       int total = 0;
+
+       dprintk(DEBUG_VFS, "\n");
+
+       rsize = v9ses->maxdata - V9FS_IOHDRSZ;
+       if (v9f->iounit != 0 && rsize > v9f->iounit)
+               rsize = v9f->iounit;
+
+       do {
+               if (count < rsize)
+                       rsize = count;
+
+               result = v9fs_t_read(v9ses, fid, *offset, rsize, &fcall);
+
+               if (result < 0) {
+                       printk(KERN_ERR "9P2000: v9fs_t_read returned %d\n",
+                              result);
+
+                       kfree(fcall);
+                       return total;
+               } else
+                       *offset += result;
+
+               /* XXX - extra copy */
+               memcpy(buffer, fcall->params.rread.data, result);
+               count -= result;
+               buffer += result;
+               total += result;
+
+               kfree(fcall);
+
+               if (result < rsize)
+                       break;
+       } while (count);
+
+       return total;
+}
+
+/**
+ * v9fs_file_read - read from a file
+ * @filep: file pointer to read
+ * @data: data buffer to read data into
+ * @count: size of buffer
+ * @offset: offset at which to read data
+ *
+ */
+
+static ssize_t
+v9fs_file_read(struct file *filp, char __user * data, size_t count,
+              loff_t * offset)
+{
+       int retval = -1;
+       int ret = 0;
+       char *buffer;
+
+       buffer = kmalloc(count, GFP_KERNEL);
+       if (!buffer)
+               return -ENOMEM;
+
+       retval = v9fs_read(filp, buffer, count, offset);
+       if (retval > 0) {
+               if ((ret = copy_to_user(data, buffer, retval)) != 0) {
+                       dprintk(DEBUG_ERROR, "Problem copying to user %d\n",
+                               ret);
+                       retval = ret;
+               }
+       }
+
+       kfree(buffer);
+
+       return retval;
+}
+
+/**
+ * v9fs_write - write to a file
+ * @filep: file pointer to write
+ * @data: data buffer to write data from
+ * @count: size of buffer
+ * @offset: offset at which to write data
+ *
+ */
+
+static ssize_t
+v9fs_write(struct file *filp, char *buffer, size_t count, loff_t * offset)
+{
+       struct inode *inode = filp->f_dentry->d_inode;
+       struct v9fs_session_info *v9ses = v9fs_inode2v9ses(inode);
+       struct v9fs_fid *v9fid = filp->private_data;
+       struct v9fs_fcall *fcall;
+       int fid = v9fid->fid;
+       int result = -EIO;
+       int rsize = 0;
+       int total = 0;
+
+       dprintk(DEBUG_VFS, "data %p count %d offset %x\n", buffer, (int)count,
+               (int)*offset);
+       rsize = v9ses->maxdata - V9FS_IOHDRSZ;
+       if (v9fid->iounit != 0 && rsize > v9fid->iounit)
+               rsize = v9fid->iounit;
+
+       dump_data(buffer, count);
+
+       do {
+               if (count < rsize)
+                       rsize = count;
+
+               result =
+                   v9fs_t_write(v9ses, fid, *offset, rsize, buffer, &fcall);
+               if (result < 0) {
+                       eprintk(KERN_ERR, "error while writing: %s(%d)\n",
+                               FCALL_ERROR(fcall), result);
+                       kfree(fcall);
+                       return result;
+               } else
+                       *offset += result;
+
+               kfree(fcall);
+
+               if (result != rsize) {
+                       eprintk(KERN_ERR,
+                               "short write: v9fs_t_write returned %d\n",
+                               result);
+                       break;
+               }
+
+               count -= result;
+               buffer += result;
+               total += result;
+       } while (count);
+
+       return total;
+}
+
+/**
+ * v9fs_file_write - write to a file
+ * @filep: file pointer to write
+ * @data: data buffer to write data from
+ * @count: size of buffer
+ * @offset: offset at which to write data
+ *
+ */
+
+static ssize_t
+v9fs_file_write(struct file *filp, const char __user * data,
+               size_t count, loff_t * offset)
+{
+       int ret = -1;
+       char *buffer;
+
+       buffer = kmalloc(count, GFP_KERNEL);
+       if (buffer == NULL)
+               return -ENOMEM;
+
+       ret = copy_from_user(buffer, data, count);
+       if (ret) {
+               dprintk(DEBUG_ERROR, "Problem copying from user\n");
+               ret = -EFAULT;
+       } else {
+               ret = v9fs_write(filp, buffer, count, offset);
+       }
+
+       kfree(buffer);
+
+       return ret;
+}
+
+struct file_operations v9fs_file_operations = {
+       .llseek = generic_file_llseek,
+       .read = v9fs_file_read,
+       .write = v9fs_file_write,
+       .open = v9fs_file_open,
+       .release = v9fs_dir_release,
+       .lock = v9fs_file_lock,
+};
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