2007-10-21 23:42:19 +00:00
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/*
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* Copyright (C) Neil Brown 2002
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* Copyright (C) Christoph Hellwig 2007
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*
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* This file contains the code mapping from inodes to NFS file handles,
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* and for mapping back from file handles to dentries.
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*
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* For details on why we do all the strange and hairy things in here
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2009-10-27 18:41:35 +00:00
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* take a look at Documentation/filesystems/nfs/Exporting.
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2007-10-21 23:42:19 +00:00
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*/
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2007-07-17 11:04:28 +00:00
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#include <linux/exportfs.h>
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2005-04-16 22:20:36 +00:00
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#include <linux/fs.h>
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#include <linux/file.h>
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#include <linux/module.h>
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2007-07-17 11:04:30 +00:00
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#include <linux/mount.h>
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2005-04-16 22:20:36 +00:00
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#include <linux/namei.h>
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2008-11-13 23:39:22 +00:00
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#include <linux/sched.h>
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2005-04-16 22:20:36 +00:00
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2007-07-17 11:04:31 +00:00
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#define dprintk(fmt, args...) do{}while(0)
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2005-04-16 22:20:36 +00:00
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2012-06-26 17:58:53 +00:00
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static int get_name(const struct path *path, char *name, struct dentry *child);
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2007-07-17 11:04:31 +00:00
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2007-10-21 23:42:19 +00:00
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static int exportfs_get_name(struct vfsmount *mnt, struct dentry *dir,
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char *name, struct dentry *child)
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2007-07-17 11:04:31 +00:00
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{
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2007-10-21 23:42:17 +00:00
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const struct export_operations *nop = dir->d_sb->s_export_op;
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2012-06-26 17:58:53 +00:00
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struct path path = {.mnt = mnt, .dentry = dir};
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2007-07-17 11:04:31 +00:00
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if (nop->get_name)
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return nop->get_name(dir, name, child);
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else
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2012-06-26 17:58:53 +00:00
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return get_name(&path, name, child);
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2007-07-17 11:04:31 +00:00
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}
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2005-04-16 22:20:36 +00:00
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2007-07-17 11:04:32 +00:00
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/*
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* Check if the dentry or any of it's aliases is acceptable.
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*/
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2006-01-19 01:43:52 +00:00
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static struct dentry *
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find_acceptable_alias(struct dentry *result,
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int (*acceptable)(void *context, struct dentry *dentry),
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void *context)
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{
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struct dentry *dentry, *toput = NULL;
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2011-01-07 06:50:06 +00:00
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struct inode *inode;
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2006-01-19 01:43:52 +00:00
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2007-07-17 11:04:32 +00:00
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if (acceptable(context, result))
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return result;
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2011-01-07 06:50:06 +00:00
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inode = result->d_inode;
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spin_lock(&inode->i_lock);
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2014-10-26 23:19:16 +00:00
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hlist_for_each_entry(dentry, &inode->i_dentry, d_u.d_alias) {
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2011-01-07 06:49:43 +00:00
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dget(dentry);
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2011-01-07 06:50:06 +00:00
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spin_unlock(&inode->i_lock);
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2006-01-19 01:43:52 +00:00
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if (toput)
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dput(toput);
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if (dentry != result && acceptable(context, dentry)) {
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dput(result);
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return dentry;
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}
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2011-01-07 06:50:06 +00:00
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spin_lock(&inode->i_lock);
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2006-01-19 01:43:52 +00:00
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toput = dentry;
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}
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2011-01-07 06:50:06 +00:00
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spin_unlock(&inode->i_lock);
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2006-01-19 01:43:52 +00:00
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if (toput)
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dput(toput);
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return NULL;
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}
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2013-10-17 01:09:30 +00:00
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static bool dentry_connected(struct dentry *dentry)
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{
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dget(dentry);
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while (dentry->d_flags & DCACHE_DISCONNECTED) {
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struct dentry *parent = dget_parent(dentry);
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dput(dentry);
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if (IS_ROOT(dentry)) {
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dput(parent);
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return false;
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}
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dentry = parent;
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}
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dput(dentry);
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return true;
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}
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2013-09-09 20:15:13 +00:00
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static void clear_disconnected(struct dentry *dentry)
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{
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dget(dentry);
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while (dentry->d_flags & DCACHE_DISCONNECTED) {
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struct dentry *parent = dget_parent(dentry);
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WARN_ON_ONCE(IS_ROOT(dentry));
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spin_lock(&dentry->d_lock);
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dentry->d_flags &= ~DCACHE_DISCONNECTED;
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spin_unlock(&dentry->d_lock);
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dput(dentry);
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dentry = parent;
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}
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dput(dentry);
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}
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2013-10-17 15:13:00 +00:00
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/*
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* Reconnect a directory dentry with its parent.
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*
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* This can return a dentry, or NULL, or an error.
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*
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* In the first case the returned dentry is the parent of the given
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* dentry, and may itself need to be reconnected to its parent.
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*
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* In the NULL case, a concurrent VFS operation has either renamed or
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* removed this directory. The concurrent operation has reconnected our
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* dentry, so we no longer need to.
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*/
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static struct dentry *reconnect_one(struct vfsmount *mnt,
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struct dentry *dentry, char *nbuf)
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{
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struct dentry *parent;
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struct dentry *tmp;
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int err;
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parent = ERR_PTR(-EACCES);
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2016-01-22 20:40:57 +00:00
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inode_lock(dentry->d_inode);
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2013-10-17 15:13:00 +00:00
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if (mnt->mnt_sb->s_export_op->get_parent)
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parent = mnt->mnt_sb->s_export_op->get_parent(dentry);
|
2016-01-22 20:40:57 +00:00
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inode_unlock(dentry->d_inode);
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2013-10-17 15:13:00 +00:00
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if (IS_ERR(parent)) {
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dprintk("%s: get_parent of %ld failed, err %d\n",
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__func__, dentry->d_inode->i_ino, PTR_ERR(parent));
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return parent;
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}
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dprintk("%s: find name of %lu in %lu\n", __func__,
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dentry->d_inode->i_ino, parent->d_inode->i_ino);
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err = exportfs_get_name(mnt, parent, nbuf, dentry);
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if (err == -ENOENT)
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goto out_reconnected;
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if (err)
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goto out_err;
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dprintk("%s: found name: %s\n", __func__, nbuf);
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2016-04-14 23:12:42 +00:00
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tmp = lookup_one_len_unlocked(nbuf, parent, strlen(nbuf));
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2013-10-17 15:13:00 +00:00
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if (IS_ERR(tmp)) {
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dprintk("%s: lookup failed: %d\n", __func__, PTR_ERR(tmp));
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goto out_err;
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}
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if (tmp != dentry) {
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2016-04-14 23:12:42 +00:00
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/*
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* Somebody has renamed it since exportfs_get_name();
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* great, since it could've only been renamed if it
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* got looked up and thus connected, and it would
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* remain connected afterwards. We are done.
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*/
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2013-10-17 15:13:00 +00:00
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dput(tmp);
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goto out_reconnected;
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}
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dput(tmp);
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if (IS_ROOT(dentry)) {
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err = -ESTALE;
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goto out_err;
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}
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return parent;
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out_err:
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dput(parent);
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return ERR_PTR(err);
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out_reconnected:
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dput(parent);
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/*
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* Someone must have renamed our entry into another parent, in
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* which case it has been reconnected by the rename.
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*
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* Or someone removed it entirely, in which case filehandle
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* lookup will succeed but the directory is now IS_DEAD and
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* subsequent operations on it will fail.
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*
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* Alternatively, maybe there was no race at all, and the
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* filesystem is just corrupt and gave us a parent that doesn't
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* actually contain any entry pointing to this inode. So,
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* double check that this worked and return -ESTALE if not:
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*/
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if (!dentry_connected(dentry))
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return ERR_PTR(-ESTALE);
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return NULL;
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}
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2007-07-17 11:04:33 +00:00
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/*
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* Make sure target_dir is fully connected to the dentry tree.
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2005-04-16 22:20:36 +00:00
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*
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2013-10-23 00:59:19 +00:00
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* On successful return, DCACHE_DISCONNECTED will be cleared on
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* target_dir, and target_dir->d_parent->...->d_parent will reach the
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* root of the filesystem.
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*
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* Whenever DCACHE_DISCONNECTED is unset, target_dir is fully connected.
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* But the converse is not true: target_dir may have DCACHE_DISCONNECTED
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* set but already be connected. In that case we'll verify the
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* connection to root and then clear the flag.
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*
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* Note that target_dir could be removed by a concurrent operation. In
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* that case reconnect_path may still succeed with target_dir fully
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* connected, but further operations using the filehandle will fail when
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* necessary (due to S_DEAD being set on the directory).
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2005-04-16 22:20:36 +00:00
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*/
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2007-07-17 11:04:33 +00:00
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static int
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2008-08-11 16:39:47 +00:00
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reconnect_path(struct vfsmount *mnt, struct dentry *target_dir, char *nbuf)
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2005-04-16 22:20:36 +00:00
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{
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2013-10-18 01:34:21 +00:00
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struct dentry *dentry, *parent;
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2005-04-16 22:20:36 +00:00
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2013-10-18 01:34:21 +00:00
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dentry = dget(target_dir);
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2005-04-16 22:20:36 +00:00
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2013-10-18 01:34:21 +00:00
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while (dentry->d_flags & DCACHE_DISCONNECTED) {
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2013-10-18 01:42:35 +00:00
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BUG_ON(dentry == mnt->mnt_sb->s_root);
|
2013-10-16 19:48:53 +00:00
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2013-10-18 01:34:21 +00:00
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if (IS_ROOT(dentry))
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parent = reconnect_one(mnt, dentry, nbuf);
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else
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parent = dget_parent(dentry);
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if (!parent)
|
2013-09-09 20:15:13 +00:00
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break;
|
2013-10-18 01:42:35 +00:00
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dput(dentry);
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2013-10-18 01:34:21 +00:00
|
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|
if (IS_ERR(parent))
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return PTR_ERR(parent);
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dentry = parent;
|
2005-04-16 22:20:36 +00:00
|
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}
|
2013-10-18 01:34:21 +00:00
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dput(dentry);
|
2013-10-17 01:09:30 +00:00
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clear_disconnected(target_dir);
|
2007-07-17 11:04:33 +00:00
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return 0;
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}
|
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|
2005-04-16 22:20:36 +00:00
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struct getdents_callback {
|
2013-05-15 17:52:59 +00:00
|
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struct dir_context ctx;
|
2005-04-16 22:20:36 +00:00
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char *name; /* name that was found. It already points to a
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buffer NAME_MAX+1 is size */
|
2013-09-10 15:41:12 +00:00
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u64 ino; /* the inum we are looking for */
|
2005-04-16 22:20:36 +00:00
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int found; /* inode matched? */
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int sequence; /* sequence counter */
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};
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|
|
|
|
|
|
/*
|
|
|
|
* A rather strange filldir function to capture
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|
|
|
* the name matching the specified inode number.
|
|
|
|
*/
|
2014-10-30 16:37:34 +00:00
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static int filldir_one(struct dir_context *ctx, const char *name, int len,
|
2006-10-03 08:13:46 +00:00
|
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|
loff_t pos, u64 ino, unsigned int d_type)
|
2005-04-16 22:20:36 +00:00
|
|
|
{
|
2014-10-30 16:37:34 +00:00
|
|
|
struct getdents_callback *buf =
|
|
|
|
container_of(ctx, struct getdents_callback, ctx);
|
2005-04-16 22:20:36 +00:00
|
|
|
int result = 0;
|
|
|
|
|
|
|
|
buf->sequence++;
|
2013-09-06 20:55:36 +00:00
|
|
|
if (buf->ino == ino && len <= NAME_MAX) {
|
2005-04-16 22:20:36 +00:00
|
|
|
memcpy(buf->name, name, len);
|
|
|
|
buf->name[len] = '\0';
|
|
|
|
buf->found = 1;
|
|
|
|
result = -1;
|
|
|
|
}
|
|
|
|
return result;
|
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* get_name - default export_operations->get_name function
|
2014-06-04 23:11:15 +00:00
|
|
|
* @path: the directory in which to find a name
|
2005-04-16 22:20:36 +00:00
|
|
|
* @name: a pointer to a %NAME_MAX+1 char buffer to store the name
|
|
|
|
* @child: the dentry for the child directory.
|
|
|
|
*
|
|
|
|
* calls readdir on the parent until it finds an entry with
|
|
|
|
* the same inode number as the child, and returns that.
|
|
|
|
*/
|
2012-06-26 17:58:53 +00:00
|
|
|
static int get_name(const struct path *path, char *name, struct dentry *child)
|
2005-04-16 22:20:36 +00:00
|
|
|
{
|
2008-11-13 23:39:22 +00:00
|
|
|
const struct cred *cred = current_cred();
|
2012-06-26 17:58:53 +00:00
|
|
|
struct inode *dir = path->dentry->d_inode;
|
2005-04-16 22:20:36 +00:00
|
|
|
int error;
|
|
|
|
struct file *file;
|
2013-09-10 15:41:12 +00:00
|
|
|
struct kstat stat;
|
|
|
|
struct path child_path = {
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|
|
|
.mnt = path->mnt,
|
|
|
|
.dentry = child,
|
|
|
|
};
|
2013-05-23 02:22:04 +00:00
|
|
|
struct getdents_callback buffer = {
|
|
|
|
.ctx.actor = filldir_one,
|
|
|
|
.name = name,
|
|
|
|
};
|
2005-04-16 22:20:36 +00:00
|
|
|
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|
|
|
error = -ENOTDIR;
|
|
|
|
if (!dir || !S_ISDIR(dir->i_mode))
|
|
|
|
goto out;
|
|
|
|
error = -EINVAL;
|
|
|
|
if (!dir->i_fop)
|
|
|
|
goto out;
|
2013-09-10 15:41:12 +00:00
|
|
|
/*
|
|
|
|
* inode->i_ino is unsigned long, kstat->ino is u64, so the
|
|
|
|
* former would be insufficient on 32-bit hosts when the
|
|
|
|
* filesystem supports 64-bit inode numbers. So we need to
|
|
|
|
* actually call ->getattr, not just read i_ino:
|
|
|
|
*/
|
|
|
|
error = vfs_getattr_nosec(&child_path, &stat);
|
|
|
|
if (error)
|
|
|
|
return error;
|
|
|
|
buffer.ino = stat.ino;
|
2005-04-16 22:20:36 +00:00
|
|
|
/*
|
|
|
|
* Open the directory ...
|
|
|
|
*/
|
2012-06-26 17:58:53 +00:00
|
|
|
file = dentry_open(path, O_RDONLY, cred);
|
2005-04-16 22:20:36 +00:00
|
|
|
error = PTR_ERR(file);
|
|
|
|
if (IS_ERR(file))
|
|
|
|
goto out;
|
|
|
|
|
|
|
|
error = -EINVAL;
|
2013-05-23 01:44:23 +00:00
|
|
|
if (!file->f_op->iterate)
|
2005-04-16 22:20:36 +00:00
|
|
|
goto out_close;
|
|
|
|
|
|
|
|
buffer.sequence = 0;
|
|
|
|
while (1) {
|
|
|
|
int old_seq = buffer.sequence;
|
|
|
|
|
2013-05-15 17:52:59 +00:00
|
|
|
error = iterate_dir(file, &buffer.ctx);
|
2008-08-24 11:29:52 +00:00
|
|
|
if (buffer.found) {
|
|
|
|
error = 0;
|
|
|
|
break;
|
|
|
|
}
|
2005-04-16 22:20:36 +00:00
|
|
|
|
|
|
|
if (error < 0)
|
|
|
|
break;
|
|
|
|
|
|
|
|
error = -ENOENT;
|
|
|
|
if (old_seq == buffer.sequence)
|
|
|
|
break;
|
|
|
|
}
|
|
|
|
|
|
|
|
out_close:
|
|
|
|
fput(file);
|
|
|
|
out:
|
|
|
|
return error;
|
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* export_encode_fh - default export_operations->encode_fh function
|
2012-04-02 18:34:06 +00:00
|
|
|
* @inode: the object to encode
|
2014-06-04 23:11:15 +00:00
|
|
|
* @fid: where to store the file handle fragment
|
2005-04-16 22:20:36 +00:00
|
|
|
* @max_len: maximum length to store there
|
2012-04-02 18:34:06 +00:00
|
|
|
* @parent: parent directory inode, if wanted
|
2005-04-16 22:20:36 +00:00
|
|
|
*
|
|
|
|
* This default encode_fh function assumes that the 32 inode number
|
|
|
|
* is suitable for locating an inode, and that the generation number
|
|
|
|
* can be used to check that it is still valid. It places them in the
|
|
|
|
* filehandle fragment where export_decode_fh expects to find them.
|
|
|
|
*/
|
2012-04-02 18:34:06 +00:00
|
|
|
static int export_encode_fh(struct inode *inode, struct fid *fid,
|
|
|
|
int *max_len, struct inode *parent)
|
2005-04-16 22:20:36 +00:00
|
|
|
{
|
|
|
|
int len = *max_len;
|
2007-10-21 23:42:03 +00:00
|
|
|
int type = FILEID_INO32_GEN;
|
2011-01-29 13:13:25 +00:00
|
|
|
|
2012-04-02 18:34:06 +00:00
|
|
|
if (parent && (len < 4)) {
|
2011-01-29 13:13:25 +00:00
|
|
|
*max_len = 4;
|
2012-08-29 14:10:10 +00:00
|
|
|
return FILEID_INVALID;
|
2011-01-29 13:13:25 +00:00
|
|
|
} else if (len < 2) {
|
|
|
|
*max_len = 2;
|
2012-08-29 14:10:10 +00:00
|
|
|
return FILEID_INVALID;
|
2011-01-29 13:13:25 +00:00
|
|
|
}
|
2005-04-16 22:20:36 +00:00
|
|
|
|
|
|
|
len = 2;
|
2007-10-21 23:42:03 +00:00
|
|
|
fid->i32.ino = inode->i_ino;
|
|
|
|
fid->i32.gen = inode->i_generation;
|
2012-04-02 18:34:06 +00:00
|
|
|
if (parent) {
|
2007-10-21 23:42:03 +00:00
|
|
|
fid->i32.parent_ino = parent->i_ino;
|
|
|
|
fid->i32.parent_gen = parent->i_generation;
|
2005-04-16 22:20:36 +00:00
|
|
|
len = 4;
|
2007-10-21 23:42:03 +00:00
|
|
|
type = FILEID_INO32_GEN_PARENT;
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
|
|
|
*max_len = len;
|
|
|
|
return type;
|
|
|
|
}
|
|
|
|
|
2012-12-18 00:05:08 +00:00
|
|
|
int exportfs_encode_inode_fh(struct inode *inode, struct fid *fid,
|
|
|
|
int *max_len, struct inode *parent)
|
|
|
|
{
|
|
|
|
const struct export_operations *nop = inode->i_sb->s_export_op;
|
|
|
|
|
|
|
|
if (nop && nop->encode_fh)
|
|
|
|
return nop->encode_fh(inode, fid->raw, max_len, parent);
|
|
|
|
|
|
|
|
return export_encode_fh(inode, fid, max_len, parent);
|
|
|
|
}
|
|
|
|
EXPORT_SYMBOL_GPL(exportfs_encode_inode_fh);
|
|
|
|
|
2007-10-21 23:42:03 +00:00
|
|
|
int exportfs_encode_fh(struct dentry *dentry, struct fid *fid, int *max_len,
|
2007-07-17 11:04:30 +00:00
|
|
|
int connectable)
|
|
|
|
{
|
2007-07-17 11:04:31 +00:00
|
|
|
int error;
|
2012-04-02 18:34:06 +00:00
|
|
|
struct dentry *p = NULL;
|
|
|
|
struct inode *inode = dentry->d_inode, *parent = NULL;
|
2007-07-17 11:04:30 +00:00
|
|
|
|
2012-04-02 18:34:06 +00:00
|
|
|
if (connectable && !S_ISDIR(inode->i_mode)) {
|
|
|
|
p = dget_parent(dentry);
|
|
|
|
/*
|
|
|
|
* note that while p might've ceased to be our parent already,
|
|
|
|
* it's still pinned by and still positive.
|
|
|
|
*/
|
|
|
|
parent = p->d_inode;
|
|
|
|
}
|
2012-12-18 00:05:08 +00:00
|
|
|
|
|
|
|
error = exportfs_encode_inode_fh(inode, fid, max_len, parent);
|
2012-04-02 18:34:06 +00:00
|
|
|
dput(p);
|
2007-07-17 11:04:31 +00:00
|
|
|
|
|
|
|
return error;
|
2007-07-17 11:04:30 +00:00
|
|
|
}
|
|
|
|
EXPORT_SYMBOL_GPL(exportfs_encode_fh);
|
|
|
|
|
2007-10-21 23:42:03 +00:00
|
|
|
struct dentry *exportfs_decode_fh(struct vfsmount *mnt, struct fid *fid,
|
|
|
|
int fh_len, int fileid_type,
|
|
|
|
int (*acceptable)(void *, struct dentry *), void *context)
|
2007-07-17 11:04:30 +00:00
|
|
|
{
|
2007-10-21 23:42:17 +00:00
|
|
|
const struct export_operations *nop = mnt->mnt_sb->s_export_op;
|
2007-10-21 23:42:05 +00:00
|
|
|
struct dentry *result, *alias;
|
2008-08-11 16:39:47 +00:00
|
|
|
char nbuf[NAME_MAX+1];
|
2007-10-21 23:42:05 +00:00
|
|
|
int err;
|
2007-07-17 11:04:30 +00:00
|
|
|
|
2007-10-21 23:42:05 +00:00
|
|
|
/*
|
|
|
|
* Try to get any dentry for the given file handle from the filesystem.
|
|
|
|
*/
|
2011-01-29 13:13:26 +00:00
|
|
|
if (!nop || !nop->fh_to_dentry)
|
|
|
|
return ERR_PTR(-ESTALE);
|
2007-10-21 23:42:05 +00:00
|
|
|
result = nop->fh_to_dentry(mnt->mnt_sb, fid, fh_len, fileid_type);
|
2008-12-08 23:24:18 +00:00
|
|
|
if (!result)
|
|
|
|
result = ERR_PTR(-ESTALE);
|
2007-10-21 23:42:05 +00:00
|
|
|
if (IS_ERR(result))
|
|
|
|
return result;
|
|
|
|
|
VFS: (Scripted) Convert S_ISLNK/DIR/REG(dentry->d_inode) to d_is_*(dentry)
Convert the following where appropriate:
(1) S_ISLNK(dentry->d_inode) to d_is_symlink(dentry).
(2) S_ISREG(dentry->d_inode) to d_is_reg(dentry).
(3) S_ISDIR(dentry->d_inode) to d_is_dir(dentry). This is actually more
complicated than it appears as some calls should be converted to
d_can_lookup() instead. The difference is whether the directory in
question is a real dir with a ->lookup op or whether it's a fake dir with
a ->d_automount op.
In some circumstances, we can subsume checks for dentry->d_inode not being
NULL into this, provided we the code isn't in a filesystem that expects
d_inode to be NULL if the dirent really *is* negative (ie. if we're going to
use d_inode() rather than d_backing_inode() to get the inode pointer).
Note that the dentry type field may be set to something other than
DCACHE_MISS_TYPE when d_inode is NULL in the case of unionmount, where the VFS
manages the fall-through from a negative dentry to a lower layer. In such a
case, the dentry type of the negative union dentry is set to the same as the
type of the lower dentry.
However, if you know d_inode is not NULL at the call site, then you can use
the d_is_xxx() functions even in a filesystem.
There is one further complication: a 0,0 chardev dentry may be labelled
DCACHE_WHITEOUT_TYPE rather than DCACHE_SPECIAL_TYPE. Strictly, this was
intended for special directory entry types that don't have attached inodes.
The following perl+coccinelle script was used:
use strict;
my @callers;
open($fd, 'git grep -l \'S_IS[A-Z].*->d_inode\' |') ||
die "Can't grep for S_ISDIR and co. callers";
@callers = <$fd>;
close($fd);
unless (@callers) {
print "No matches\n";
exit(0);
}
my @cocci = (
'@@',
'expression E;',
'@@',
'',
'- S_ISLNK(E->d_inode->i_mode)',
'+ d_is_symlink(E)',
'',
'@@',
'expression E;',
'@@',
'',
'- S_ISDIR(E->d_inode->i_mode)',
'+ d_is_dir(E)',
'',
'@@',
'expression E;',
'@@',
'',
'- S_ISREG(E->d_inode->i_mode)',
'+ d_is_reg(E)' );
my $coccifile = "tmp.sp.cocci";
open($fd, ">$coccifile") || die $coccifile;
print($fd "$_\n") || die $coccifile foreach (@cocci);
close($fd);
foreach my $file (@callers) {
chomp $file;
print "Processing ", $file, "\n";
system("spatch", "--sp-file", $coccifile, $file, "--in-place", "--no-show-diff") == 0 ||
die "spatch failed";
}
[AV: overlayfs parts skipped]
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-01-29 12:02:35 +00:00
|
|
|
if (d_is_dir(result)) {
|
2007-10-21 23:42:05 +00:00
|
|
|
/*
|
|
|
|
* This request is for a directory.
|
|
|
|
*
|
|
|
|
* On the positive side there is only one dentry for each
|
|
|
|
* directory inode. On the negative side this implies that we
|
|
|
|
* to ensure our dentry is connected all the way up to the
|
|
|
|
* filesystem root.
|
|
|
|
*/
|
|
|
|
if (result->d_flags & DCACHE_DISCONNECTED) {
|
2008-08-11 16:39:47 +00:00
|
|
|
err = reconnect_path(mnt, result, nbuf);
|
2007-10-21 23:42:05 +00:00
|
|
|
if (err)
|
|
|
|
goto err_result;
|
|
|
|
}
|
|
|
|
|
|
|
|
if (!acceptable(context, result)) {
|
|
|
|
err = -EACCES;
|
|
|
|
goto err_result;
|
|
|
|
}
|
|
|
|
|
|
|
|
return result;
|
2007-07-17 11:04:31 +00:00
|
|
|
} else {
|
2007-10-21 23:42:05 +00:00
|
|
|
/*
|
|
|
|
* It's not a directory. Life is a little more complicated.
|
|
|
|
*/
|
|
|
|
struct dentry *target_dir, *nresult;
|
|
|
|
|
|
|
|
/*
|
|
|
|
* See if either the dentry we just got from the filesystem
|
|
|
|
* or any alias for it is acceptable. This is always true
|
|
|
|
* if this filesystem is exported without the subtreecheck
|
|
|
|
* option. If the filesystem is exported with the subtree
|
|
|
|
* check option there's a fair chance we need to look at
|
|
|
|
* the parent directory in the file handle and make sure
|
|
|
|
* it's connected to the filesystem root.
|
|
|
|
*/
|
|
|
|
alias = find_acceptable_alias(result, acceptable, context);
|
|
|
|
if (alias)
|
|
|
|
return alias;
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Try to extract a dentry for the parent directory from the
|
|
|
|
* file handle. If this fails we'll have to give up.
|
|
|
|
*/
|
|
|
|
err = -ESTALE;
|
|
|
|
if (!nop->fh_to_parent)
|
|
|
|
goto err_result;
|
|
|
|
|
|
|
|
target_dir = nop->fh_to_parent(mnt->mnt_sb, fid,
|
|
|
|
fh_len, fileid_type);
|
2008-12-08 23:24:18 +00:00
|
|
|
if (!target_dir)
|
|
|
|
goto err_result;
|
2007-10-21 23:42:05 +00:00
|
|
|
err = PTR_ERR(target_dir);
|
|
|
|
if (IS_ERR(target_dir))
|
|
|
|
goto err_result;
|
|
|
|
|
|
|
|
/*
|
|
|
|
* And as usual we need to make sure the parent directory is
|
|
|
|
* connected to the filesystem root. The VFS really doesn't
|
|
|
|
* like disconnected directories..
|
|
|
|
*/
|
2008-08-11 16:39:47 +00:00
|
|
|
err = reconnect_path(mnt, target_dir, nbuf);
|
2007-10-21 23:42:05 +00:00
|
|
|
if (err) {
|
|
|
|
dput(target_dir);
|
|
|
|
goto err_result;
|
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Now that we've got both a well-connected parent and a
|
|
|
|
* dentry for the inode we're after, make sure that our
|
|
|
|
* inode is actually connected to the parent.
|
|
|
|
*/
|
2007-10-21 23:42:19 +00:00
|
|
|
err = exportfs_get_name(mnt, target_dir, nbuf, result);
|
2007-10-21 23:42:05 +00:00
|
|
|
if (!err) {
|
2016-01-22 20:40:57 +00:00
|
|
|
inode_lock(target_dir->d_inode);
|
2007-10-21 23:42:05 +00:00
|
|
|
nresult = lookup_one_len(nbuf, target_dir,
|
|
|
|
strlen(nbuf));
|
2016-01-22 20:40:57 +00:00
|
|
|
inode_unlock(target_dir->d_inode);
|
2007-10-21 23:42:05 +00:00
|
|
|
if (!IS_ERR(nresult)) {
|
|
|
|
if (nresult->d_inode) {
|
|
|
|
dput(result);
|
|
|
|
result = nresult;
|
|
|
|
} else
|
|
|
|
dput(nresult);
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* At this point we are done with the parent, but it's pinned
|
|
|
|
* by the child dentry anyway.
|
|
|
|
*/
|
|
|
|
dput(target_dir);
|
|
|
|
|
|
|
|
/*
|
|
|
|
* And finally make sure the dentry is actually acceptable
|
|
|
|
* to NFSD.
|
|
|
|
*/
|
|
|
|
alias = find_acceptable_alias(result, acceptable, context);
|
|
|
|
if (!alias) {
|
|
|
|
err = -EACCES;
|
|
|
|
goto err_result;
|
|
|
|
}
|
|
|
|
|
|
|
|
return alias;
|
2007-07-17 11:04:31 +00:00
|
|
|
}
|
|
|
|
|
2007-10-21 23:42:05 +00:00
|
|
|
err_result:
|
|
|
|
dput(result);
|
|
|
|
return ERR_PTR(err);
|
2007-07-17 11:04:30 +00:00
|
|
|
}
|
|
|
|
EXPORT_SYMBOL_GPL(exportfs_decode_fh);
|
|
|
|
|
2005-04-16 22:20:36 +00:00
|
|
|
MODULE_LICENSE("GPL");
|