From: Al Viro <[email protected]> 3.12-stable review patch. If anyone has any objections, please let me know.
=============== commit 31dec1327e377b6d91a8a6c92b5cd8513939a233 upstream. There used to be a bunch of tree-walkers in dcache.c, all alike. try_to_ascend() had been introduced to abstract a piece of logics duplicated in all of them. These days all these tree-walkers are implemented via the same iterator (d_walk()), which is the only remaining caller of try_to_ascend(), so let's fold it back... Signed-off-by: Al Viro <[email protected]> Signed-off-by: Jiri Slaby <[email protected]> --- fs/dcache.c | 49 ++++++++++++++++++------------------------------- 1 file changed, 18 insertions(+), 31 deletions(-) diff --git a/fs/dcache.c b/fs/dcache.c index 7839720ce9f2..116af43494e6 100644 --- a/fs/dcache.c +++ b/fs/dcache.c @@ -465,7 +465,7 @@ static struct dentry *d_kill(struct dentry *dentry, struct dentry *parent) { list_del(&dentry->d_u.d_child); /* - * Inform try_to_ascend() that we are no longer attached to the + * Inform d_walk() that we are no longer attached to the * dentry tree */ dentry->d_flags |= DCACHE_DENTRY_KILLED; @@ -1060,34 +1060,6 @@ void shrink_dcache_sb(struct super_block *sb) } EXPORT_SYMBOL(shrink_dcache_sb); -/* - * This tries to ascend one level of parenthood, but - * we can race with renaming, so we need to re-check - * the parenthood after dropping the lock and check - * that the sequence number still matches. - */ -static struct dentry *try_to_ascend(struct dentry *old, unsigned seq) -{ - struct dentry *new = old->d_parent; - - rcu_read_lock(); - spin_unlock(&old->d_lock); - spin_lock(&new->d_lock); - - /* - * might go back up the wrong parent if we have had a rename - * or deletion - */ - if (new != old->d_parent || - (old->d_flags & DCACHE_DENTRY_KILLED) || - need_seqretry(&rename_lock, seq)) { - spin_unlock(&new->d_lock); - new = NULL; - } - rcu_read_unlock(); - return new; -} - /** * enum d_walk_ret - action to talke during tree walk * @D_WALK_CONTINUE: contrinue walk @@ -1176,9 +1148,24 @@ resume: */ if (this_parent != parent) { struct dentry *child = this_parent; - this_parent = try_to_ascend(this_parent, seq); - if (!this_parent) + this_parent = child->d_parent; + + rcu_read_lock(); + spin_unlock(&child->d_lock); + spin_lock(&this_parent->d_lock); + + /* + * might go back up the wrong parent if we have had a rename + * or deletion + */ + if (this_parent != child->d_parent || + (child->d_flags & DCACHE_DENTRY_KILLED) || + need_seqretry(&rename_lock, seq)) { + spin_unlock(&this_parent->d_lock); + rcu_read_unlock(); goto rename_retry; + } + rcu_read_unlock(); next = child->d_u.d_child.next; goto resume; } -- 2.1.2 -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
