From ff17fa561a04b5fdb25997fda98a2313bb471be6 Mon Sep 17 00:00:00 2001 From: Al Viro Date: Sun, 15 Apr 2018 18:21:47 -0400 Subject: [PATCH] d_invalidate(): unhash immediately Once that is done, we can just hunt mountpoints down one by one; no new mountpoints can be added from now on, so we don't need anything tricky in finish() callback, etc. Signed-off-by: Al Viro --- fs/dcache.c | 62 ++++++++++++++--------------------------------------- 1 file changed, 16 insertions(+), 46 deletions(-) diff --git a/fs/dcache.c b/fs/dcache.c index 86d2de63461e..449d0f895e6f 100644 --- a/fs/dcache.c +++ b/fs/dcache.c @@ -1542,78 +1542,48 @@ void shrink_dcache_for_umount(struct super_block *sb) } } -struct detach_data { - struct select_data select; - struct dentry *mountpoint; -}; -static enum d_walk_ret detach_and_collect(void *_data, struct dentry *dentry) +static enum d_walk_ret find_submount(void *_data, struct dentry *dentry) { - struct detach_data *data = _data; - + struct dentry **victim = _data; if (d_mountpoint(dentry)) { __dget_dlock(dentry); - data->mountpoint = dentry; + *victim = dentry; return D_WALK_QUIT; } - - return select_collect(&data->select, dentry); -} - -static void check_and_drop(void *_data) -{ - struct detach_data *data = _data; - - if (!data->mountpoint && list_empty(&data->select.dispose)) - __d_drop(data->select.start); + return D_WALK_CONTINUE; } /** * d_invalidate - detach submounts, prune dcache, and drop * @dentry: dentry to invalidate (aka detach, prune and drop) - * - * no dcache lock. - * - * The final d_drop is done as an atomic operation relative to - * rename_lock ensuring there are no races with d_set_mounted. This - * ensures there are no unhashed dentries on the path to a mountpoint. */ void d_invalidate(struct dentry *dentry) { - /* - * If it's already been dropped, return OK. - */ + bool had_submounts = false; spin_lock(&dentry->d_lock); if (d_unhashed(dentry)) { spin_unlock(&dentry->d_lock); return; } + __d_drop(dentry); spin_unlock(&dentry->d_lock); /* Negative dentries can be dropped without further checks */ - if (!dentry->d_inode) { - d_drop(dentry); + if (!dentry->d_inode) return; - } + shrink_dcache_parent(dentry); for (;;) { - struct detach_data data; - - data.mountpoint = NULL; - INIT_LIST_HEAD(&data.select.dispose); - data.select.start = dentry; - data.select.found = 0; - - d_walk(dentry, &data, detach_and_collect, check_and_drop); - - if (!list_empty(&data.select.dispose)) - shrink_dentry_list(&data.select.dispose); - else if (!data.mountpoint) + struct dentry *victim = NULL; + d_walk(dentry, &victim, find_submount, NULL); + if (!victim) { + if (had_submounts) + shrink_dcache_parent(dentry); return; - - if (data.mountpoint) { - detach_mounts(data.mountpoint); - dput(data.mountpoint); } + had_submounts = true; + detach_mounts(victim); + dput(victim); } } EXPORT_SYMBOL(d_invalidate); -- 2.30.2