struct fs_struct *fs = current->fs;
struct dentry *parent = nd->path.dentry;
- /*
- * It can be possible to revalidate the dentry that we started
- * the path walk with. force_reval_path may also revalidate the
- * dentry already committed to the nameidata.
- */
- if (unlikely(parent == dentry))
- return nameidata_drop_rcu(nd);
-
BUG_ON(!(nd->flags & LOOKUP_RCU));
if (nd->root.mnt) {
spin_lock(&fs->lock);
}
}
-/*
- * Call d_revalidate and handle filesystems that request rcu-walk
- * to be dropped. This may be called and return in rcu-walk mode,
- * regardless of success or error. If -ECHILD is returned, the caller
- * must return -ECHILD back up the path walk stack so path walk may
- * be restarted in ref-walk mode.
- */
-static int d_revalidate(struct dentry *dentry, struct nameidata *nd)
+static inline int d_revalidate(struct dentry *dentry, struct nameidata *nd)
{
- int status;
-
- status = dentry->d_op->d_revalidate(dentry, nd);
- if (status == -ECHILD) {
- if (nameidata_dentry_drop_rcu(nd, dentry))
- return status;
- status = dentry->d_op->d_revalidate(dentry, nd);
- }
-
- return status;
+ return dentry->d_op->d_revalidate(dentry, nd);
}
-static inline struct dentry *
+static struct dentry *
do_revalidate(struct dentry *dentry, struct nameidata *nd)
{
- int status;
-
- status = d_revalidate(dentry, nd);
+ int status = d_revalidate(dentry, nd);
if (unlikely(status <= 0)) {
/*
* The dentry failed validation.
* to return a fail status.
*/
if (status < 0) {
- /* If we're in rcu-walk, we don't have a ref */
- if (!(nd->flags & LOOKUP_RCU))
- dput(dentry);
+ dput(dentry);
dentry = ERR_PTR(status);
-
- } else {
- /* Don't d_invalidate in rcu-walk mode */
- if (nameidata_dentry_drop_rcu_maybe(nd, dentry))
- return ERR_PTR(-ECHILD);
- if (!d_invalidate(dentry)) {
- dput(dentry);
- dentry = NULL;
- }
+ } else if (!d_invalidate(dentry)) {
+ dput(dentry);
+ dentry = NULL;
}
}
return dentry;
}
+static inline struct dentry *
+do_revalidate_rcu(struct dentry *dentry, struct nameidata *nd)
+{
+ int status = d_revalidate(dentry, nd);
+ if (likely(status > 0))
+ return dentry;
+ if (status == -ECHILD) {
+ if (nameidata_dentry_drop_rcu(nd, dentry))
+ return ERR_PTR(-ECHILD);
+ return do_revalidate(dentry, nd);
+ }
+ if (status < 0)
+ return ERR_PTR(status);
+ /* Don't d_invalidate in rcu-walk mode */
+ if (nameidata_dentry_drop_rcu(nd, dentry))
+ return ERR_PTR(-ECHILD);
+ if (!d_invalidate(dentry)) {
+ dput(dentry);
+ dentry = NULL;
+ }
+ return dentry;
+}
+
static inline int need_reval_dot(struct dentry *dentry)
{
if (likely(!(dentry->d_flags & DCACHE_OP_REVALIDATE)))
* Without that kind of total limit, nasty chains of consecutive
* symlinks can cause almost arbitrarily long lookups.
*/
-static inline int do_follow_link(struct path *path, struct nameidata *nd)
+static inline int do_follow_link(struct inode *inode, struct path *path, struct nameidata *nd)
{
void *cookie;
int err = -ELOOP;
/* We drop rcu-walk here */
if (nameidata_dentry_drop_rcu_maybe(nd, path->dentry))
return -ECHILD;
+ BUG_ON(inode != path->dentry->d_inode);
if (current->link_count >= MAX_NESTED_LINKS)
goto loop;
return -ECHILD;
nd->seq = seq;
- if (dentry->d_flags & DCACHE_OP_REVALIDATE)
- goto need_revalidate;
-done2:
+ if (unlikely(dentry->d_flags & DCACHE_OP_REVALIDATE)) {
+ dentry = do_revalidate_rcu(dentry, nd);
+ if (!dentry)
+ goto need_lookup;
+ if (IS_ERR(dentry))
+ goto fail;
+ if (!(nd->flags & LOOKUP_RCU))
+ goto done;
+ }
path->mnt = mnt;
path->dentry = dentry;
if (likely(__follow_mount_rcu(nd, path, inode, false)))
if (!dentry)
goto need_lookup;
found:
- if (dentry->d_flags & DCACHE_OP_REVALIDATE)
- goto need_revalidate;
+ if (unlikely(dentry->d_flags & DCACHE_OP_REVALIDATE)) {
+ dentry = do_revalidate(dentry, nd);
+ if (!dentry)
+ goto need_lookup;
+ if (IS_ERR(dentry))
+ goto fail;
+ }
done:
path->mnt = mnt;
path->dentry = dentry;
mutex_unlock(&dir->i_mutex);
goto found;
-need_revalidate:
- dentry = do_revalidate(dentry, nd);
- if (!dentry)
- goto need_lookup;
- if (IS_ERR(dentry))
- goto fail;
- if (nd->flags & LOOKUP_RCU)
- goto done2;
- goto done;
-
fail:
return PTR_ERR(dentry);
}
goto out_dput;
if (inode->i_op->follow_link) {
- BUG_ON(inode != next.dentry->d_inode);
- err = do_follow_link(&next, nd);
+ err = do_follow_link(inode, &next, nd);
if (err)
goto return_err;
nd->inode = nd->path.dentry->d_inode;
break;
if (inode && unlikely(inode->i_op->follow_link) &&
(lookup_flags & LOOKUP_FOLLOW)) {
- BUG_ON(inode != next.dentry->d_inode);
- err = do_follow_link(&next, nd);
+ err = do_follow_link(inode, &next, nd);
if (err)
goto return_err;
nd->inode = nd->path.dentry->d_inode;
* We may need to check the cached dentry for staleness.
*/
if (need_reval_dot(nd->path.dentry)) {
+ if (nameidata_drop_rcu_last_maybe(nd))
+ return -ECHILD;
/* Note: we do not d_invalidate() */
err = d_revalidate(nd->path.dentry, nd);
if (!err)
err = -ESTALE;
if (err < 0)
break;
+ return 0;
}
return_base:
if (nameidata_drop_rcu_last_maybe(nd))
/* nd->path had been dropped */
current->total_link_count = 0;
nd->path = save;
+ nd->inode = save.dentry->d_inode;
path_get(&nd->path);
nd->flags |= LOOKUP_REVAL;
result = link_path_walk(name, nd);
/* !O_CREAT, simple open */
error = do_path_lookup(dfd, pathname, flags, &nd);
if (unlikely(error))
- goto out_filp;
+ goto out_filp2;
error = -ELOOP;
if (!(nd.flags & LOOKUP_FOLLOW)) {
if (nd.inode->i_op->follow_link)
- goto out_path;
+ goto out_path2;
}
error = -ENOTDIR;
if (nd.flags & LOOKUP_DIRECTORY) {
if (!nd.inode->i_op->lookup)
- goto out_path;
+ goto out_path2;
}
audit_inode(pathname, nd.path.dentry);
filp = finish_open(&nd, open_flag, acc_mode);
+out2:
release_open_intent(&nd);
return filp;
+out_path2:
+ path_put(&nd.path);
+out_filp2:
+ filp = ERR_PTR(error);
+ goto out2;
+
creat:
/* OK, have to create the file. Find the parent. */
error = path_init_rcu(dfd, pathname,
projects / mv-sheeva.git / blobdiff