From 46f6dac259717551916405ee3388de89fb152bca Mon Sep 17 00:00:00 2001 From: Eric Van Hensbergen Date: Thu, 2 Mar 2006 02:54:33 -0800 Subject: [PATCH] v9fs: simplify fid mapping v9fs has been plagued by an over-complicated approach trying to map Linux dentry semantics to Plan 9 fid semantics. Our previous approach called for aggressive flushing of the dcache resulting in several problems (including wierd cwd behavior when running /bin/pwd). This patch dramatically simplifies our handling of this fid management. Fids will not be clunked as promptly, but the new approach is more functionally correct. We now clunk un-open fids only when their dentry ref_count reaches 0 (and d_delete is called). Another simplification is we no longer seek to match fids to the process-id or uid of the action initiator. The uid-matching will need to be revisited when we fix the security model. Signed-off-by: Eric Van Hensbergen Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/9p/fid.c | 94 ++++--------------------------------------------------------- 1 file changed, 6 insertions(+), 88 deletions(-) (limited to 'fs/9p/fid.c') diff --git a/fs/9p/fid.c b/fs/9p/fid.c index c27f546dd25b..c4d13bf904d2 100644 --- a/fs/9p/fid.c +++ b/fs/9p/fid.c @@ -1,7 +1,7 @@ /* * V9FS FID Management * - * Copyright (C) 2005 by Eric Van Hensbergen + * Copyright (C) 2005, 2006 by Eric Van Hensbergen * * 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 @@ -57,7 +57,6 @@ int v9fs_fid_insert(struct v9fs_fid *fid, struct dentry *dentry) } fid->uid = current->uid; - fid->pid = current->pid; list_add(&fid->list, fid_list); return 0; } @@ -88,7 +87,7 @@ struct v9fs_fid *v9fs_fid_create(struct v9fs_session_info *v9ses, int fid) new->rdir_fcall = NULL; INIT_LIST_HEAD(&new->list); - return new; + return new; } /** @@ -103,76 +102,14 @@ void v9fs_fid_destroy(struct v9fs_fid *fid) 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, *fid; - 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; - } - - fid = v9fs_fid_create(v9ses, fidnum); - if (fid) { - err = v9fs_fid_insert(fid, dentry); - if (err < 0) { - kfree(fid); - goto clunk_fid; - } - } - - return fid; - -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. + * find a fid in the dentry + * + * TODO: only match fids that have the same uid as current user * */ @@ -187,26 +124,7 @@ struct v9fs_fid *v9fs_fid_lookup(struct dentry *dentry) return_fid = list_entry(fid_list->next, struct v9fs_fid, list); 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; - } + dprintk(DEBUG_ERROR, "Couldn't find a fid in dentry\n"); } return return_fid; -- cgit v1.2.3