diff options
Diffstat (limited to 'fs/9p/fid.c')
| -rw-r--r-- | fs/9p/fid.c | 241 |
1 files changed, 241 insertions, 0 deletions
diff --git a/fs/9p/fid.c b/fs/9p/fid.c new file mode 100644 index 000000000000..821c9c4d76aa --- /dev/null +++ b/fs/9p/fid.c @@ -0,0 +1,241 @@ +/* + * V9FS FID Management + * + * Copyright (C) 2005 by Eric Van Hensbergen <ericvh@gmail.com> + * + * 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/config.h> +#include <linux/module.h> +#include <linux/errno.h> +#include <linux/fs.h> +#include <linux/idr.h> + +#include "debug.h" +#include "v9fs.h" +#include "9p.h" +#include "v9fs_vfs.h" +#include "transport.h" +#include "mux.h" +#include "conv.h" +#include "fid.h" + +/** + * v9fs_fid_insert - add a fid to a dentry + * @fid: fid to add + * @dentry: dentry that it is being added to + * + */ + +static int v9fs_fid_insert(struct v9fs_fid *fid, struct dentry *dentry) +{ + struct list_head *fid_list = (struct list_head *)dentry->d_fsdata; + dprintk(DEBUG_9P, "fid %d (%p) dentry %s (%p)\n", fid->fid, fid, + dentry->d_iname, dentry); + if (dentry->d_fsdata == NULL) { + dentry->d_fsdata = + kmalloc(sizeof(struct list_head), GFP_KERNEL); + if (dentry->d_fsdata == NULL) { + dprintk(DEBUG_ERROR, "Out of memory\n"); + return -ENOMEM; + } + fid_list = (struct list_head *)dentry->d_fsdata; + INIT_LIST_HEAD(fid_list); /* Initialize list head */ + } + + fid->uid = current->uid; + fid->pid = current->pid; + list_add(&fid->list, fid_list); + return 0; +} + +/** + * v9fs_fid_create - allocate a FID structure + * @dentry - dentry to link newly created fid to + * + */ + +struct v9fs_fid *v9fs_fid_create(struct dentry *dentry) +{ + struct v9fs_fid *new; + + new = kmalloc(sizeof(struct v9fs_fid), GFP_KERNEL); + if (new == NULL) { + dprintk(DEBUG_ERROR, "Out of Memory\n"); + return ERR_PTR(-ENOMEM); + } + + new->fid = -1; + new->fidopen = 0; + new->fidcreate = 0; + new->fidclunked = 0; + new->iounit = 0; + + if (v9fs_fid_insert(new, dentry) == 0) + return new; + else { + dprintk(DEBUG_ERROR, "Problems inserting to dentry\n"); + kfree(new); + return NULL; + } +} + +/** + * v9fs_fid_destroy - deallocate a FID structure + * @fid: fid to destroy + * + */ + +void v9fs_fid_destroy(struct v9fs_fid *fid) +{ + list_del(&fid->list); + kfree(fid); +} + +/** + * v9fs_fid_lookup - retrieve the right fid from a particular dentry + * @dentry: dentry to look for fid in + * @type: intent of lookup (operation or traversal) + * + * search list of fids associated with a dentry for a fid with a matching + * thread id or uid. If that fails, look up the dentry's parents to see if you + * can find a matching fid. + * + */ + +struct v9fs_fid *v9fs_fid_lookup(struct dentry *dentry, int type) +{ + struct list_head *fid_list = (struct list_head *)dentry->d_fsdata; + struct v9fs_fid *current_fid = NULL; + struct v9fs_fid *temp = NULL; + struct v9fs_fid *return_fid = NULL; + int found_parent = 0; + int found_user = 0; + + dprintk(DEBUG_9P, " dentry: %s (%p) type %d\n", dentry->d_iname, dentry, + type); + + if (fid_list && !list_empty(fid_list)) { + list_for_each_entry_safe(current_fid, temp, fid_list, list) { + if (current_fid->uid == current->uid) { + if (return_fid == NULL) { + if ((type == FID_OP) + || (!current_fid->fidopen)) { + return_fid = current_fid; + found_user = 1; + } + } + } + if (current_fid->pid == current->real_parent->pid) { + if ((return_fid == NULL) || (found_parent) + || (found_user)) { + if ((type == FID_OP) + || (!current_fid->fidopen)) { + return_fid = current_fid; + found_parent = 1; + found_user = 0; + } + } + } + if (current_fid->pid == current->pid) { + if ((type == FID_OP) || + (!current_fid->fidopen)) { + return_fid = current_fid; + found_parent = 0; + found_user = 0; + } + } + } + } + + /* we are at the root but didn't match */ + if ((!return_fid) && (dentry->d_parent == dentry)) { + /* TODO: clone attach with new uid */ + return_fid = current_fid; + } + + if (!return_fid) { + struct dentry *par = current->fs->pwd->d_parent; + int count = 1; + while (par != NULL) { + if (par == dentry) + break; + count++; + if (par == par->d_parent) { + dprintk(DEBUG_ERROR, + "got to root without finding dentry\n"); + break; + } + par = par->d_parent; + } + +/* XXX - there may be some duplication we can get rid of */ + if (par == dentry) { + /* we need to fid_lookup the starting point */ + int fidnum = -1; + int oldfid = -1; + int result = -1; + struct v9fs_session_info *v9ses = + v9fs_inode2v9ses(current->fs->pwd->d_inode); + + current_fid = + v9fs_fid_lookup(current->fs->pwd, FID_WALK); + if (current_fid == NULL) { + dprintk(DEBUG_ERROR, + "process cwd doesn't have a fid\n"); + return return_fid; + } + oldfid = current_fid->fid; + par = current->fs->pwd; + /* TODO: take advantage of multiwalk */ + + fidnum = v9fs_get_idpool(&v9ses->fidpool); + if (fidnum < 0) { + dprintk(DEBUG_ERROR, + "could not get a new fid num\n"); + return return_fid; + } + + while (par != dentry) { + result = + v9fs_t_walk(v9ses, oldfid, fidnum, "..", + NULL); + if (result < 0) { + dprintk(DEBUG_ERROR, + "problem walking to parent\n"); + + break; + } + oldfid = fidnum; + if (par == par->d_parent) { + dprintk(DEBUG_ERROR, + "can't find dentry\n"); + break; + } + par = par->d_parent; + } + if (par == dentry) { + return_fid = v9fs_fid_create(dentry); + return_fid->fid = fidnum; + } + } + } + + return return_fid; +} |