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

/*

 *  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,

};

/*

 * 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,

};

/*

 *  linux/fs/9p/vfs_file.c

 *

 * This file contians vfs file ops for 9P2000.

 *

 *  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/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) {