18f4c64477
This avoids an indirect call in the VFS for each path component lookup. Well, at least as long as you own the directory in question, and the ACL check is unnecessary. Reviewed-by: James Morris <jmorris@namei.org> Acked-by: Serge Hallyn <serue@us.ibm.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
65 lines
1.9 KiB
C
65 lines
1.9 KiB
C
/*
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* JFFS2 -- Journalling Flash File System, Version 2.
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*
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* Copyright © 2001-2007 Red Hat, Inc.
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*
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* Created by David Woodhouse <dwmw2@infradead.org>
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*
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* For licensing information, see the file 'LICENCE' in this directory.
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*
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*/
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#include <linux/kernel.h>
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#include <linux/slab.h>
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#include <linux/fs.h>
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#include <linux/namei.h>
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#include "nodelist.h"
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static void *jffs2_follow_link(struct dentry *dentry, struct nameidata *nd);
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const struct inode_operations jffs2_symlink_inode_operations =
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{
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.readlink = generic_readlink,
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.follow_link = jffs2_follow_link,
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.check_acl = jffs2_check_acl,
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.setattr = jffs2_setattr,
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.setxattr = jffs2_setxattr,
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.getxattr = jffs2_getxattr,
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.listxattr = jffs2_listxattr,
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.removexattr = jffs2_removexattr
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};
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static void *jffs2_follow_link(struct dentry *dentry, struct nameidata *nd)
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{
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struct jffs2_inode_info *f = JFFS2_INODE_INFO(dentry->d_inode);
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char *p = (char *)f->target;
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/*
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* We don't acquire the f->sem mutex here since the only data we
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* use is f->target.
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*
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* 1. If we are here the inode has already built and f->target has
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* to point to the target path.
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* 2. Nobody uses f->target (if the inode is symlink's inode). The
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* exception is inode freeing function which frees f->target. But
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* it can't be called while we are here and before VFS has
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* stopped using our f->target string which we provide by means of
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* nd_set_link() call.
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*/
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if (!p) {
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printk(KERN_ERR "jffs2_follow_link(): can't find symlink target\n");
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p = ERR_PTR(-EIO);
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}
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D1(printk(KERN_DEBUG "jffs2_follow_link(): target path is '%s'\n", (char *) f->target));
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nd_set_link(nd, p);
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/*
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* We will unlock the f->sem mutex but VFS will use the f->target string. This is safe
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* since the only way that may cause f->target to be changed is iput() operation.
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* But VFS will not use f->target after iput() has been called.
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*/
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return NULL;
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}
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