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/vfs_dentry.c | 45 ++++++++------------------------------------- 1 file changed, 8 insertions(+), 37 deletions(-) (limited to 'fs/9p/vfs_dentry.c') diff --git a/fs/9p/vfs_dentry.c b/fs/9p/vfs_dentry.c index 2dd806dac9f1..12c9cc926b71 100644 --- a/fs/9p/vfs_dentry.c +++ b/fs/9p/vfs_dentry.c @@ -43,47 +43,18 @@ #include "fid.h" /** - * v9fs_dentry_validate - VFS dcache hook to validate cache - * @dentry: dentry that is being validated - * @nd: path data + * v9fs_dentry_delete - called when dentry refcount equals 0 + * @dentry: dentry in question * - * 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. + * By returning 1 here we should remove cacheing of unused + * dentry components. * */ -static int v9fs_dentry_validate(struct dentry *dentry, struct nameidata *nd) +int v9fs_dentry_delete(struct dentry *dentry) { - struct dentry *dc = current->fs->pwd; - - dprintk(DEBUG_VFS, "dentry: %s (%p)\n", dentry->d_iname, dentry); - if (v9fs_fid_lookup(dentry)) { - 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; + dprintk(DEBUG_VFS, " dentry: %s (%p)\n", dentry->d_iname, dentry); + return 1; } /** @@ -118,6 +89,6 @@ void v9fs_dentry_release(struct dentry *dentry) } struct dentry_operations v9fs_dentry_operations = { - .d_revalidate = v9fs_dentry_validate, + .d_delete = v9fs_dentry_delete, .d_release = v9fs_dentry_release, }; -- cgit v1.2.3