/* * V9FS FID Management * * Copyright (C) 2005, 2006 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 version 2 * as published by the Free Software Foundation. * * 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/sched.h> #include <linux/idr.h> #include <asm/semaphore.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 * */ 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; 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 v9fs_session_info *v9ses, int fid) { struct v9fs_fid *new; dprintk(DEBUG_9P, "fid create fid %d\n", fid); 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->fidclunked = 0; new->iounit = 0; new->rdir_pos = 0; new->rdir_fcall = NULL; init_MUTEX(&new->lock); INIT_LIST_HEAD(&new->list); return new; } /** * 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 - return a locked fid from a dentry * @dentry: dentry to look for fid in * * find a fid in the dentry, obtain its semaphore and return a reference to it. * code calling lookup is responsible for releasing lock * * TODO: only match fids that have the same uid as current user * */ struct v9fs_fid *v9fs_fid_lookup(struct dentry *dentry) { struct list_head *fid_list = (struct list_head *)dentry->d_fsdata; struct v9fs_fid *return_fid = NULL; dprintk(DEBUG_9P, " dentry: %s (%p)\n", dentry->d_iname, dentry); if (fid_list) return_fid = list_entry(fid_list->next, struct v9fs_fid, list); if (!return_fid) { dprintk(DEBUG_ERROR, "Couldn't find a fid in dentry\n"); return_fid = ERR_PTR(-EBADF); } if(down_interruptible(&return_fid->lock)) return ERR_PTR(-EINTR); return return_fid; } /** * v9fs_fid_clone - lookup the fid for a dentry, clone a private copy and * release it * @dentry: dentry to look for fid in * * find a fid in the dentry and then clone to a new private fid * * TODO: only match fids that have the same uid as current user * */ struct v9fs_fid *v9fs_fid_clone(struct dentry *dentry) { struct v9fs_session_info *v9ses = v9fs_inode2v9ses(dentry->d_inode); struct v9fs_fid *base_fid, *new_fid = ERR_PTR(-EBADF); struct v9fs_fcall *fcall = NULL; int fid, err; base_fid = v9fs_fid_lookup(dentry); if(IS_ERR(base_fid)) return base_fid; if(base_fid) { /* clone fid */ fid = v9fs_get_idpool(&v9ses->fidpool); if (fid < 0) { eprintk(KERN_WARNING, "newfid fails!\n"); new_fid = ERR_PTR(-ENOSPC); goto Release_Fid; } err = v9fs_t_walk(v9ses, base_fid->fid, fid, NULL, &fcall); if (err < 0) { dprintk(DEBUG_ERROR, "clone walk didn't work\n"); v9fs_put_idpool(fid, &v9ses->fidpool); new_fid = ERR_PTR(err); goto Free_Fcall; } new_fid = v9fs_fid_create(v9ses, fid); if (new_fid == NULL) { dprintk(DEBUG_ERROR, "out of memory\n"); new_fid = ERR_PTR(-ENOMEM); } Free_Fcall: kfree(fcall); } Release_Fid: up(&base_fid->lock); return new_fid; } void v9fs_fid_clunk(struct v9fs_session_info *v9ses, struct v9fs_fid *fid) { v9fs_t_clunk(v9ses, fid->fid); v9fs_fid_destroy(fid); }