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dd00aaeb34
Add the GL_NOBLOCK flag to the locking requests in gfs2_permission() and gfs2_drevalidate() when called with the MAY_NOT_BLOCK flag and LOOKUP_RCU flag, respectively. This will cause the locking requests to be handled without sleeping if possible. We bail out with -ECHILD if we can't grant the glock immediately. Make sure not to dget() + dput() the parent dentry in gfs2_drevalidate() in LOOKUP_RCU mode; dput() is a sleeping operation. Signed-off-by: Abhi Das <adas@redhat.com> Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
114 lines
2.4 KiB
C
114 lines
2.4 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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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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#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 = NULL;
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struct gfs2_sbd *sdp;
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struct gfs2_inode *dip;
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struct inode *dinode, *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, valid = 0;
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int had_lock = 0;
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if (flags & LOOKUP_RCU) {
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dinode = d_inode_rcu(READ_ONCE(dentry->d_parent));
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if (!dinode)
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return -ECHILD;
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} else {
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parent = dget_parent(dentry);
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dinode = d_inode(parent);
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}
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sdp = GFS2_SB(dinode);
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dip = GFS2_I(dinode);
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inode = d_inode(dentry);
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if (inode) {
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if (is_bad_inode(inode))
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goto out;
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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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valid = 1;
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goto out;
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}
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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,
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flags & LOOKUP_RCU ? GL_NOBLOCK : 0, &d_gh);
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if (error)
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goto out;
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}
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error = gfs2_dir_check(d_inode(parent), &dentry->d_name, ip);
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valid = inode ? !error : (error == -ENOENT);
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if (!had_lock)
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gfs2_glock_dq_uninit(&d_gh);
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out:
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dput(parent);
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return valid;
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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 (d_really_is_negative(dentry))
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return 0;
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ginode = GFS2_I(d_inode(dentry));
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if (!gfs2_holder_initialized(&ginode->i_iopen_gh))
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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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