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authorAl Viro <viro@zeniv.linux.org.uk>2018-03-11 20:15:46 +0100
committerAl Viro <viro@zeniv.linux.org.uk>2018-03-29 21:07:49 +0200
commit42177007aa277af3e37bf2ae3efdfe795c81d700 (patch)
tree225e98af6cdea24f5d38ddbfe3b16a2eebaab047 /fs/dcache.c
parentmake non-exchanging __d_move() copy ->d_parent rather than swap them (diff)
downloadlinux-42177007aa277af3e37bf2ae3efdfe795c81d700.tar.xz
linux-42177007aa277af3e37bf2ae3efdfe795c81d700.zip
fold dentry_lock_for_move() into its sole caller and clean it up
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'fs/dcache.c')
-rw-r--r--fs/dcache.c49
1 files changed, 23 insertions, 26 deletions
diff --git a/fs/dcache.c b/fs/dcache.c
index 0a58038091f2..c159a4b304cf 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -2773,25 +2773,6 @@ static void copy_name(struct dentry *dentry, struct dentry *target)
kfree_rcu(old_name, u.head);
}
-static void dentry_lock_for_move(struct dentry *dentry, struct dentry *target)
-{
- if (IS_ROOT(dentry) || dentry->d_parent == target->d_parent)
- spin_lock(&target->d_parent->d_lock);
- else {
- if (d_ancestor(dentry->d_parent, target->d_parent)) {
- spin_lock(&dentry->d_parent->d_lock);
- spin_lock_nested(&target->d_parent->d_lock,
- DENTRY_D_LOCK_NESTED);
- } else {
- spin_lock(&target->d_parent->d_lock);
- spin_lock_nested(&dentry->d_parent->d_lock,
- DENTRY_D_LOCK_NESTED);
- }
- }
- spin_lock_nested(&dentry->d_lock, 2);
- spin_lock_nested(&target->d_lock, 3);
-}
-
/*
* __d_move - move a dentry
* @dentry: entry to move
@@ -2806,16 +2787,34 @@ static void dentry_lock_for_move(struct dentry *dentry, struct dentry *target)
static void __d_move(struct dentry *dentry, struct dentry *target,
bool exchange)
{
- struct dentry *old_parent;
+ struct dentry *old_parent, *p;
struct inode *dir = NULL;
unsigned n;
- if (!dentry->d_inode)
- printk(KERN_WARNING "VFS: moving negative dcache entry\n");
- BUG_ON(d_ancestor(dentry, target));
+ WARN_ON(!dentry->d_inode);
+ if (WARN_ON(dentry == target))
+ return;
+
BUG_ON(d_ancestor(target, dentry));
+ old_parent = dentry->d_parent;
+ p = d_ancestor(old_parent, target);
+ if (IS_ROOT(dentry)) {
+ BUG_ON(p);
+ spin_lock(&target->d_parent->d_lock);
+ } else if (!p) {
+ /* target is not a descendent of dentry->d_parent */
+ spin_lock(&target->d_parent->d_lock);
+ spin_lock_nested(&old_parent->d_lock, DENTRY_D_LOCK_NESTED);
+ } else {
+ BUG_ON(p == dentry);
+ spin_lock(&old_parent->d_lock);
+ if (p != target)
+ spin_lock_nested(&target->d_parent->d_lock,
+ DENTRY_D_LOCK_NESTED);
+ }
+ spin_lock_nested(&dentry->d_lock, 2);
+ spin_lock_nested(&target->d_lock, 3);
- dentry_lock_for_move(dentry, target);
if (unlikely(d_in_lookup(target))) {
dir = target->d_parent->d_inode;
n = start_dir_add(dir);
@@ -2825,8 +2824,6 @@ static void __d_move(struct dentry *dentry, struct dentry *target,
write_seqcount_begin(&dentry->d_seq);
write_seqcount_begin_nested(&target->d_seq, DENTRY_D_LOCK_NESTED);
- old_parent = dentry->d_parent;
-
/* unhash both */
if (!d_unhashed(dentry))
___d_drop(dentry);