1 /* 2 * V9FS FID Management 3 * 4 * Copyright (C) 2005, 2006 by Eric Van Hensbergen <ericvh@gmail.com> 5 * 6 * This program is free software; you can redistribute it and/or modify 7 * it under the terms of the GNU General Public License version 2 8 * as published by the Free Software Foundation. 9 * 10 * This program is distributed in the hope that it will be useful, 11 * but WITHOUT ANY WARRANTY; without even the implied warranty of 12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 13 * GNU General Public License for more details. 14 * 15 * You should have received a copy of the GNU General Public License 16 * along with this program; if not, write to: 17 * Free Software Foundation 18 * 51 Franklin Street, Fifth Floor 19 * Boston, MA 02111-1301 USA 20 * 21 */ 22 23 #include <linux/module.h> 24 #include <linux/errno.h> 25 #include <linux/fs.h> 26 #include <linux/sched.h> 27 #include <linux/idr.h> 28 #include <asm/semaphore.h> 29 #include <net/9p/9p.h> 30 #include <net/9p/client.h> 31 32 #include "v9fs.h" 33 #include "v9fs_vfs.h" 34 #include "fid.h" 35 36 /** 37 * v9fs_fid_insert - add a fid to a dentry 38 * @fid: fid to add 39 * @dentry: dentry that it is being added to 40 * 41 */ 42 43 int v9fs_fid_add(struct dentry *dentry, struct p9_fid *fid) 44 { 45 struct v9fs_dentry *dent; 46 47 P9_DPRINTK(P9_DEBUG_VFS, "fid %d dentry %s\n", 48 fid->fid, dentry->d_iname); 49 50 dent = dentry->d_fsdata; 51 if (!dent) { 52 dent = kmalloc(sizeof(struct v9fs_dentry), GFP_KERNEL); 53 if (!dent) 54 return -ENOMEM; 55 56 spin_lock_init(&dent->lock); 57 INIT_LIST_HEAD(&dent->fidlist); 58 dentry->d_fsdata = dent; 59 } 60 61 spin_lock(&dent->lock); 62 list_add(&fid->dlist, &dent->fidlist); 63 spin_unlock(&dent->lock); 64 65 return 0; 66 } 67 68 /** 69 * v9fs_fid_lookup - return a locked fid from a dentry 70 * @dentry: dentry to look for fid in 71 * 72 * find a fid in the dentry, obtain its semaphore and return a reference to it. 73 * code calling lookup is responsible for releasing lock 74 * 75 * TODO: only match fids that have the same uid as current user 76 * 77 */ 78 79 struct p9_fid *v9fs_fid_lookup(struct dentry *dentry) 80 { 81 struct v9fs_dentry *dent; 82 struct p9_fid *fid; 83 84 P9_DPRINTK(P9_DEBUG_VFS, " dentry: %s (%p)\n", dentry->d_iname, dentry); 85 dent = dentry->d_fsdata; 86 if (dent) 87 fid = list_entry(dent->fidlist.next, struct p9_fid, dlist); 88 else 89 fid = ERR_PTR(-EBADF); 90 91 P9_DPRINTK(P9_DEBUG_VFS, " fid: %p\n", fid); 92 return fid; 93 } 94 95 /** 96 * v9fs_fid_clone - lookup the fid for a dentry, clone a private copy and 97 * release it 98 * @dentry: dentry to look for fid in 99 * 100 * find a fid in the dentry and then clone to a new private fid 101 * 102 * TODO: only match fids that have the same uid as current user 103 * 104 */ 105 106 struct p9_fid *v9fs_fid_clone(struct dentry *dentry) 107 { 108 struct p9_fid *ofid, *fid; 109 110 P9_DPRINTK(P9_DEBUG_VFS, " dentry: %s (%p)\n", dentry->d_iname, dentry); 111 ofid = v9fs_fid_lookup(dentry); 112 if (IS_ERR(ofid)) 113 return ofid; 114 115 fid = p9_client_walk(ofid, 0, NULL, 1); 116 return fid; 117 } 118