}
EXPORT_SYMBOL(path_get);
-/**
- * path_get_long - get a long reference to a path
- * @path: path to get the reference to
- *
- * Given a path increment the reference count to the dentry and the vfsmount.
- */
-void path_get_long(struct path *path)
-{
- mntget_long(path->mnt);
- dget(path->dentry);
-}
-
/**
* path_put - put a reference to a path
* @path: path to put the reference to
}
EXPORT_SYMBOL(path_put);
-/**
- * path_put_long - put a long reference to a path
- * @path: path to put the reference to
- *
- * Given a path decrement the reference count to the dentry and the vfsmount.
- */
-void path_put_long(struct path *path)
-{
- dput(path->dentry);
- mntput_long(path->mnt);
-}
-
/**
* nameidata_drop_rcu - drop this nameidata out of rcu-walk
* @nd: nameidata pathwalk data to drop
touch_atime(link->mnt, dentry);
nd_set_link(nd, NULL);
- if (link->mnt != nd->path.mnt) {
- path_to_nameidata(link, nd);
- nd->inode = nd->path.dentry->d_inode;
- dget(dentry);
- }
- mntget(link->mnt);
+ if (link->mnt == nd->path.mnt)
+ mntget(link->mnt);
nd->last_type = LAST_BIND;
*p = dentry->d_inode->i_op->follow_link(dentry, nd);
bool *need_mntput)
{
struct vfsmount *mnt;
+ int err;
if (!path->dentry->d_op || !path->dentry->d_op->d_automount)
return -EREMOTE;
+ /* We don't want to mount if someone supplied AT_NO_AUTOMOUNT
+ * and this is the terminal part of the path.
+ */
+ if ((flags & LOOKUP_NO_AUTOMOUNT) && !(flags & LOOKUP_CONTINUE))
+ return -EISDIR; /* we actually want to stop here */
+
/* We want to mount if someone is trying to open/create a file of any
* type under the mountpoint, wants to traverse through the mountpoint
* or wants to open the mounted directory.
return -EREMOTE;
return PTR_ERR(mnt);
}
+
if (!mnt) /* mount collision */
return 0;
- if (mnt->mnt_sb == path->mnt->mnt_sb &&
- mnt->mnt_root == path->dentry) {
- mntput(mnt);
- return -ELOOP;
+ err = finish_automount(mnt, path);
+
+ switch (err) {
+ case -EBUSY:
+ /* Someone else made a mount here whilst we were busy */
+ return 0;
+ case 0:
+ dput(path->dentry);
+ if (*need_mntput)
+ mntput(path->mnt);
+ path->mnt = mnt;
+ path->dentry = dget(mnt->mnt_root);
+ *need_mntput = true;
+ return 0;
+ default:
+ return err;
}
- dput(path->dentry);
- if (*need_mntput)
- mntput(path->mnt);
- path->mnt = mnt;
- path->dentry = dget(mnt->mnt_root);
- *need_mntput = true;
- return 0;
}
/*
* Handle a dentry that is managed in some way.
+ * - Flagged for transit management (autofs)
* - Flagged as mountpoint
* - Flagged as automount point
*
while (managed = ACCESS_ONCE(path->dentry->d_flags),
managed &= DCACHE_MANAGED_DENTRY,
unlikely(managed != 0)) {
+ /* Allow the filesystem to manage the transit without i_mutex
+ * being held. */
+ if (managed & DCACHE_MANAGE_TRANSIT) {
+ BUG_ON(!path->dentry->d_op);
+ BUG_ON(!path->dentry->d_op->d_manage);
+ ret = path->dentry->d_op->d_manage(path->dentry,
+ false, false);
+ if (ret < 0)
+ return ret == -EISDIR ? 0 : ret;
+ }
+
/* Transit to a mounted filesystem. */
if (managed & DCACHE_MOUNTED) {
struct vfsmount *mounted = lookup_mnt(path);
return 0;
}
-int follow_down(struct path *path)
+int follow_down_one(struct path *path)
{
struct vfsmount *mounted;
/*
* Skip to top of mountpoint pile in rcuwalk mode. We abort the rcu-walk if we
- * meet an automount point and we're not walking to "..". True is returned to
+ * meet a managed dentry and we're not walking to "..". True is returned to
* continue, false to abort.
*/
static bool __follow_mount_rcu(struct nameidata *nd, struct path *path,
{
while (d_mountpoint(path->dentry)) {
struct vfsmount *mounted;
+ if (unlikely(path->dentry->d_flags & DCACHE_MANAGE_TRANSIT) &&
+ !reverse_transit &&
+ path->dentry->d_op->d_manage(path->dentry, false, true) < 0)
+ return false;
mounted = __lookup_mnt(path->mnt, path->dentry, 1);
if (!mounted)
break;
return 0;
}
+/*
+ * Follow down to the covering mount currently visible to userspace. At each
+ * point, the filesystem owning that dentry may be queried as to whether the
+ * caller is permitted to proceed or not.
+ *
+ * Care must be taken as namespace_sem may be held (indicated by mounting_here
+ * being true).
+ */
+int follow_down(struct path *path, bool mounting_here)
+{
+ unsigned managed;
+ int ret;
+
+ while (managed = ACCESS_ONCE(path->dentry->d_flags),
+ unlikely(managed & DCACHE_MANAGED_DENTRY)) {
+ /* Allow the filesystem to manage the transit without i_mutex
+ * being held.
+ *
+ * We indicate to the filesystem if someone is trying to mount
+ * something here. This gives autofs the chance to deny anyone
+ * other than its daemon the right to mount on its
+ * superstructure.
+ *
+ * The filesystem may sleep at this point.
+ */
+ if (managed & DCACHE_MANAGE_TRANSIT) {
+ BUG_ON(!path->dentry->d_op);
+ BUG_ON(!path->dentry->d_op->d_manage);
+ ret = path->dentry->d_op->d_manage(
+ path->dentry, mounting_here, false);
+ if (ret < 0)
+ return ret == -EISDIR ? 0 : ret;
+ }
+
+ /* Transit to a mounted filesystem. */
+ if (managed & DCACHE_MOUNTED) {
+ struct vfsmount *mounted = lookup_mnt(path);
+ if (!mounted)
+ break;
+ dput(path->dentry);
+ mntput(path->mnt);
+ path->mnt = mounted;
+ path->dentry = dget(mounted->mnt_root);
+ continue;
+ }
+
+ /* Don't handle automount points here */
+ break;
+ }
+ return 0;
+}
+
/*
* Skip to top of mountpoint pile in refwalk mode for follow_dotdot()
*/
path->mnt = mnt;
path->dentry = dentry;
err = follow_managed(path, nd->flags);
- if (unlikely(err < 0))
+ if (unlikely(err < 0)) {
+ path_put_conditional(path, nd);
return err;
+ }
*inode = path->dentry->d_inode;
return 0;
return PTR_ERR(dentry);
}
-/*
- * This is a temporary kludge to deal with "automount" symlinks; proper
- * solution is to trigger them on follow_mount(), so that do_lookup()
- * would DTRT. To be killed before 2.6.34-final.
- */
-static inline int follow_on_final(struct inode *inode, unsigned lookup_flags)
-{
- return inode && unlikely(inode->i_op->follow_link) &&
- ((lookup_flags & LOOKUP_FOLLOW) || S_ISDIR(inode->i_mode));
-}
-
/*
* Name resolution.
* This is the basic name resolution function, turning a pathname into
err = do_lookup(nd, &this, &next, &inode);
if (err)
break;
- if (follow_on_final(inode, lookup_flags)) {
+ if (inode && unlikely(inode->i_op->follow_link) &&
+ (lookup_flags & LOOKUP_FOLLOW)) {
if (nameidata_dentry_drop_rcu_maybe(nd, next.dentry))
return -ECHILD;
BUG_ON(inode != next.dentry->d_inode);
struct inode *linki = link.dentry->d_inode;
void *cookie;
error = -ELOOP;
- /* S_ISDIR part is a temporary automount kludge */
- if (!(nd.flags & LOOKUP_FOLLOW) && !S_ISDIR(linki->i_mode))
+ if (!(nd.flags & LOOKUP_FOLLOW))
goto exit_dput;
if (count++ == 32)
goto exit_dput;
};
EXPORT_SYMBOL(user_path_at);
+EXPORT_SYMBOL(follow_down_one);
EXPORT_SYMBOL(follow_down);
EXPORT_SYMBOL(follow_up);
EXPORT_SYMBOL(get_write_access); /* binfmt_aout */
git.openpandora.org / pandora-kernel.git / blobdiff