cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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locks.c (2671B)

      1// SPDX-License-Identifier: GPL-2.0-or-later
      2/*
      3 * locks.c
      4 *
      5 * Userspace file locking support
      6 *
      7 * Copyright (C) 2007 Oracle.  All rights reserved.
      8 */
      9
     10#include <linux/fs.h>
     11#include <linux/fcntl.h>
     12
     13#include <cluster/masklog.h>
     14
     15#include "ocfs2.h"
     16
     17#include "dlmglue.h"
     18#include "file.h"
     19#include "inode.h"
     20#include "locks.h"
     21
     22static int ocfs2_do_flock(struct file *file, struct inode *inode,
     23			  int cmd, struct file_lock *fl)
     24{
     25	int ret = 0, level = 0, trylock = 0;
     26	struct ocfs2_file_private *fp = file->private_data;
     27	struct ocfs2_lock_res *lockres = &fp->fp_flock;
     28
     29	if (fl->fl_type == F_WRLCK)
     30		level = 1;
     31	if (!IS_SETLKW(cmd))
     32		trylock = 1;
     33
     34	mutex_lock(&fp->fp_mutex);
     35
     36	if (lockres->l_flags & OCFS2_LOCK_ATTACHED &&
     37	    lockres->l_level > LKM_NLMODE) {
     38		int old_level = 0;
     39		struct file_lock request;
     40
     41		if (lockres->l_level == LKM_EXMODE)
     42			old_level = 1;
     43
     44		if (level == old_level)
     45			goto out;
     46
     47		/*
     48		 * Converting an existing lock is not guaranteed to be
     49		 * atomic, so we can get away with simply unlocking
     50		 * here and allowing the lock code to try at the new
     51		 * level.
     52		 */
     53
     54		locks_init_lock(&request);
     55		request.fl_type = F_UNLCK;
     56		request.fl_flags = FL_FLOCK;
     57		locks_lock_file_wait(file, &request);
     58
     59		ocfs2_file_unlock(file);
     60	}
     61
     62	ret = ocfs2_file_lock(file, level, trylock);
     63	if (ret) {
     64		if (ret == -EAGAIN && trylock)
     65			ret = -EWOULDBLOCK;
     66		else
     67			mlog_errno(ret);
     68		goto out;
     69	}
     70
     71	ret = locks_lock_file_wait(file, fl);
     72	if (ret)
     73		ocfs2_file_unlock(file);
     74
     75out:
     76	mutex_unlock(&fp->fp_mutex);
     77
     78	return ret;
     79}
     80
     81static int ocfs2_do_funlock(struct file *file, int cmd, struct file_lock *fl)
     82{
     83	int ret;
     84	struct ocfs2_file_private *fp = file->private_data;
     85
     86	mutex_lock(&fp->fp_mutex);
     87	ocfs2_file_unlock(file);
     88	ret = locks_lock_file_wait(file, fl);
     89	mutex_unlock(&fp->fp_mutex);
     90
     91	return ret;
     92}
     93
     94/*
     95 * Overall flow of ocfs2_flock() was influenced by gfs2_flock().
     96 */
     97int ocfs2_flock(struct file *file, int cmd, struct file_lock *fl)
     98{
     99	struct inode *inode = file->f_mapping->host;
    100	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
    101
    102	if (!(fl->fl_flags & FL_FLOCK))
    103		return -ENOLCK;
    104
    105	if ((osb->s_mount_opt & OCFS2_MOUNT_LOCALFLOCKS) ||
    106	    ocfs2_mount_local(osb))
    107		return locks_lock_file_wait(file, fl);
    108
    109	if (fl->fl_type == F_UNLCK)
    110		return ocfs2_do_funlock(file, cmd, fl);
    111	else
    112		return ocfs2_do_flock(file, inode, cmd, fl);
    113}
    114
    115int ocfs2_lock(struct file *file, int cmd, struct file_lock *fl)
    116{
    117	struct inode *inode = file->f_mapping->host;
    118	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
    119
    120	if (!(fl->fl_flags & FL_POSIX))
    121		return -ENOLCK;
    122
    123	return ocfs2_plock(osb->cconn, OCFS2_I(inode)->ip_blkno, file, cmd, fl);
    124}