/* * 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 "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_session_info *v9ses, int fid, int create) { struct v9fs_fid *new; dprintk(DEBUG_9P, "fid create dentry %p, fid %d, create %d\n", dentry, fid, create); new = kmalloc(sizeof(struct v9fs_fid), GFP_KERNEL); if (new == NULL) { dprintk(DEBUG_ERROR, "Out of Memory\n"); return ERR_PTR(-ENOMEM); } new->fid = fid; new->v9ses = v9ses; new->fidopen = 0; new->fidcreate = create; new->fidclunked = 0; new->iounit = 0; new->rdir_pos = 0; new->rdir_fcall = NULL; 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_walk_up - walks from the process current directory * up to the specified dentry. */ static struct v9fs_fid *v9fs_fid_walk_up(struct dentry *dentry) { int fidnum, cfidnum, err; struct v9fs_fid *cfid; struct dentry *cde; struct v9fs_session_info *v9ses; v9ses = v9fs_inode2v9ses(current->fs->pwd->d_inode); cfid = v9fs_fid_lookup(current->fs->pwd); if (cfid == NULL) { dprintk(DEBUG_ERROR, "process cwd doesn't have a fid\n"); return ERR_PTR(-ENOENT); } cfidnum = cfid->fid; cde = 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"); err = -ENOENT; goto clunk_fid; } while (cde != dentry) { if (cde == cde->d_parent) { dprintk(DEBUG_ERROR, "can't find dentry\n"); err = -ENOENT; goto clunk_fid; } err = v9fs_t_walk(v9ses, cfidnum, fidnum, "..", NULL); if (err < 0) { dprintk(DEBUG_ERROR, "problem walking to parent\n"); goto clunk_fid; } cfidnum = fidnum; cde = cde->d_parent; } return v9fs_fid_create(dentry, v9ses, fidnum, 0); clunk_fid: v9fs_t_clunk(v9ses, fidnum); return ERR_PTR(err); } /** * 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) { 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; dprintk(DEBUG_9P, " dentry: %s (%p)\n", dentry->d_iname, dentry); if (fid_list) { list_for_each_entry_safe(current_fid, temp, fid_list, list) { if (!current_fid->fidcreate) { return_fid = current_fid; break; } } if (!return_fid) return_fid = current_fid; } /* 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) { return_fid = v9fs_fid_walk_up(dentry); if (IS_ERR(return_fid)) return_fid = NULL; } } return return_fid; } struct v9fs_fid *v9fs_fid_get_created(struct dentry *dentry) { struct list_head *fid_list; struct v9fs_fid *fid, *ftmp, *ret; dprintk(DEBUG_9P, " dentry: %s (%p)\n", dentry->d_iname, dentry); fid_list = (struct list_head *)dentry->d_fsdata; ret = NULL; if (fid_list) { list_for_each_entry_safe(fid, ftmp, fid_list, list) { if (fid->fidcreate && fid->pid == current->pid) { list_del(&fid->list); ret = fid; break; } } } dprintk(DEBUG_9P, "return %p\n", ret); return ret; }