vfs: take path_get_longterm() out of write_seqcount scope
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/fs_struct.c b/fs/fs_struct.c
index 27114b4..6324c42 100644
--- a/fs/fs_struct.c
+++ b/fs/fs_struct.c
@@ -26,11 +26,11 @@
{
struct path old_root;
+ path_get_longterm(path);
spin_lock(&fs->lock);
write_seqcount_begin(&fs->seq);
old_root = fs->root;
fs->root = *path;
- path_get_longterm(path);
write_seqcount_end(&fs->seq);
spin_unlock(&fs->lock);
if (old_root.dentry)
@@ -45,11 +45,11 @@
{
struct path old_pwd;
+ path_get_longterm(path);
spin_lock(&fs->lock);
write_seqcount_begin(&fs->seq);
old_pwd = fs->pwd;
fs->pwd = *path;
- path_get_longterm(path);
write_seqcount_end(&fs->seq);
spin_unlock(&fs->lock);
@@ -57,6 +57,14 @@
path_put_longterm(&old_pwd);
}
+static inline int replace_path(struct path *p, const struct path *old, const struct path *new)
+{
+ if (likely(p->dentry != old->dentry || p->mnt != old->mnt))
+ return 0;
+ *p = *new;
+ return 1;
+}
+
void chroot_fs_refs(struct path *old_root, struct path *new_root)
{
struct task_struct *g, *p;
@@ -68,21 +76,16 @@
task_lock(p);
fs = p->fs;
if (fs) {
+ int hits = 0;
spin_lock(&fs->lock);
write_seqcount_begin(&fs->seq);
- if (fs->root.dentry == old_root->dentry
- && fs->root.mnt == old_root->mnt) {
- path_get_longterm(new_root);
- fs->root = *new_root;
- count++;
- }
- if (fs->pwd.dentry == old_root->dentry
- && fs->pwd.mnt == old_root->mnt) {
- path_get_longterm(new_root);
- fs->pwd = *new_root;
- count++;
- }
+ hits += replace_path(&fs->root, old_root, new_root);
+ hits += replace_path(&fs->pwd, old_root, new_root);
write_seqcount_end(&fs->seq);
+ while (hits--) {
+ count++;
+ path_get_longterm(new_root);
+ }
spin_unlock(&fs->lock);
}
task_unlock(p);