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authorEric Van Hensbergen <ericvh@gmail.com>2006-03-02 02:54:33 -0800
committerLinus Torvalds <torvalds@g5.osdl.org>2006-03-02 08:33:07 -0800
commit46f6dac259717551916405ee3388de89fb152bca (patch)
tree0e6c8b4505339e90c05ec8326220286fd19fe1f4 /fs/9p/fid.c
parent74b8054c730785cd9db093e48f53337e521b6270 (diff)
[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 <ericvh@gmail.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'fs/9p/fid.c')
-rw-r--r--fs/9p/fid.c94
1 files changed, 6 insertions, 88 deletions
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 <ericvh@gmail.com>
+ * 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 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;
}
/**
@@ -104,75 +103,13 @@ void v9fs_fid_destroy(struct v9fs_fid *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;