diff options
Diffstat (limited to 'fs/9p/vfs_dentry.c')
| -rw-r--r-- | fs/9p/vfs_dentry.c | 126 |
1 files changed, 126 insertions, 0 deletions
diff --git a/fs/9p/vfs_dentry.c b/fs/9p/vfs_dentry.c new file mode 100644 index 00000000000..306c96741f8 --- /dev/null +++ b/fs/9p/vfs_dentry.c @@ -0,0 +1,126 @@ +/* + * 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, + ¤t_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, +}; |