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da53be12bb
Instances either don't look at it at all (the majority of cases) or only want it to find the superblock (which can be had as dentry->d_sb). A few cases that want more are actually safe with dentry->d_inode - the only precaution needed is the check that it hadn't been replaced with NULL by rmdir() or by overwriting rename(), which case should be simply treated as cache miss. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
141 lines
2.8 KiB
C
141 lines
2.8 KiB
C
/*
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* Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved.
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* Copyright (C) 2004-2006 Red Hat, Inc. All rights reserved.
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*
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* This copyrighted material is made available to anyone wishing to use,
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* modify, copy, or redistribute it subject to the terms and conditions
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* of the GNU General Public License version 2.
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*/
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#include <linux/spinlock.h>
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#include <linux/completion.h>
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#include <linux/buffer_head.h>
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#include <linux/gfs2_ondisk.h>
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#include <linux/namei.h>
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#include <linux/crc32.h>
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#include "gfs2.h"
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#include "incore.h"
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#include "dir.h"
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#include "glock.h"
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#include "super.h"
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#include "util.h"
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#include "inode.h"
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/**
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* gfs2_drevalidate - Check directory lookup consistency
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* @dentry: the mapping to check
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* @flags: lookup flags
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*
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* Check to make sure the lookup necessary to arrive at this inode from its
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* parent is still good.
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*
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* Returns: 1 if the dentry is ok, 0 if it isn't
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*/
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static int gfs2_drevalidate(struct dentry *dentry, unsigned int flags)
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{
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struct dentry *parent;
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struct gfs2_sbd *sdp;
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struct gfs2_inode *dip;
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struct inode *inode;
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struct gfs2_holder d_gh;
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struct gfs2_inode *ip = NULL;
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int error;
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int had_lock = 0;
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if (flags & LOOKUP_RCU)
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return -ECHILD;
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parent = dget_parent(dentry);
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sdp = GFS2_SB(parent->d_inode);
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dip = GFS2_I(parent->d_inode);
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inode = dentry->d_inode;
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if (inode) {
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if (is_bad_inode(inode))
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goto invalid;
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ip = GFS2_I(inode);
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}
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if (sdp->sd_lockstruct.ls_ops->lm_mount == NULL)
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goto valid;
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had_lock = (gfs2_glock_is_locked_by_me(dip->i_gl) != NULL);
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if (!had_lock) {
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error = gfs2_glock_nq_init(dip->i_gl, LM_ST_SHARED, 0, &d_gh);
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if (error)
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goto fail;
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}
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error = gfs2_dir_check(parent->d_inode, &dentry->d_name, ip);
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switch (error) {
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case 0:
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if (!inode)
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goto invalid_gunlock;
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break;
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case -ENOENT:
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if (!inode)
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goto valid_gunlock;
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goto invalid_gunlock;
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default:
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goto fail_gunlock;
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}
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valid_gunlock:
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if (!had_lock)
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gfs2_glock_dq_uninit(&d_gh);
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valid:
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dput(parent);
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return 1;
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invalid_gunlock:
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if (!had_lock)
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gfs2_glock_dq_uninit(&d_gh);
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invalid:
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if (inode && S_ISDIR(inode->i_mode)) {
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if (have_submounts(dentry))
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goto valid;
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shrink_dcache_parent(dentry);
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}
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d_drop(dentry);
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dput(parent);
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return 0;
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fail_gunlock:
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gfs2_glock_dq_uninit(&d_gh);
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fail:
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dput(parent);
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return 0;
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}
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static int gfs2_dhash(const struct dentry *dentry, struct qstr *str)
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{
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str->hash = gfs2_disk_hash(str->name, str->len);
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return 0;
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}
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static int gfs2_dentry_delete(const struct dentry *dentry)
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{
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struct gfs2_inode *ginode;
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if (!dentry->d_inode)
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return 0;
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ginode = GFS2_I(dentry->d_inode);
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if (!ginode->i_iopen_gh.gh_gl)
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return 0;
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if (test_bit(GLF_DEMOTE, &ginode->i_iopen_gh.gh_gl->gl_flags))
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return 1;
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return 0;
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}
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const struct dentry_operations gfs2_dops = {
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.d_revalidate = gfs2_drevalidate,
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.d_hash = gfs2_dhash,
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.d_delete = gfs2_dentry_delete,
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};
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