示例#1
0
文件: xfs_dquot.c 项目: avagin/linux
/*
 * Look up the dquot in the in-core cache.  If found, the dquot is returned
 * locked and ready to go.
 */
static struct xfs_dquot *
xfs_qm_dqget_cache_lookup(
	struct xfs_mount	*mp,
	struct xfs_quotainfo	*qi,
	struct radix_tree_root	*tree,
	xfs_dqid_t		id)
{
	struct xfs_dquot	*dqp;

restart:
	mutex_lock(&qi->qi_tree_lock);
	dqp = radix_tree_lookup(tree, id);
	if (!dqp) {
		mutex_unlock(&qi->qi_tree_lock);
		XFS_STATS_INC(mp, xs_qm_dqcachemisses);
		return NULL;
	}

	xfs_dqlock(dqp);
	if (dqp->dq_flags & XFS_DQ_FREEING) {
		xfs_dqunlock(dqp);
		mutex_unlock(&qi->qi_tree_lock);
		trace_xfs_dqget_freeing(dqp);
		delay(1);
		goto restart;
	}

	dqp->q_nrefs++;
	mutex_unlock(&qi->qi_tree_lock);

	trace_xfs_dqget_hit(dqp);
	XFS_STATS_INC(mp, xs_qm_dqcachehits);
	return dqp;
}
示例#2
0
/*
 * Given the file system, inode OR id, and type (UDQUOT/GDQUOT), return a
 * a locked dquot, doing an allocation (if requested) as needed.
 * When both an inode and an id are given, the inode's id takes precedence.
 * That is, if the id changes while we don't hold the ilock inside this
 * function, the new dquot is returned, not necessarily the one requested
 * in the id argument.
 */
int
xfs_qm_dqget(
	xfs_mount_t	*mp,
	xfs_inode_t	*ip,	  /* locked inode (optional) */
	xfs_dqid_t	id,	  /* uid/projid/gid depending on type */
	uint		type,	  /* XFS_DQ_USER/XFS_DQ_PROJ/XFS_DQ_GROUP */
	uint		flags,	  /* DQALLOC, DQSUSER, DQREPAIR, DOWARN */
	xfs_dquot_t	**O_dqpp) /* OUT : locked incore dquot */
{
	struct xfs_quotainfo	*qi = mp->m_quotainfo;
	struct radix_tree_root *tree = xfs_dquot_tree(qi, type);
	struct xfs_dquot	*dqp;
	int			error;

	ASSERT(XFS_IS_QUOTA_RUNNING(mp));
	if ((! XFS_IS_UQUOTA_ON(mp) && type == XFS_DQ_USER) ||
	    (! XFS_IS_PQUOTA_ON(mp) && type == XFS_DQ_PROJ) ||
	    (! XFS_IS_GQUOTA_ON(mp) && type == XFS_DQ_GROUP)) {
		return (ESRCH);
	}

#ifdef DEBUG
	if (xfs_do_dqerror) {
		if ((xfs_dqerror_target == mp->m_ddev_targp) &&
		    (xfs_dqreq_num++ % xfs_dqerror_mod) == 0) {
			xfs_debug(mp, "Returning error in dqget");
			return (EIO);
		}
	}

	ASSERT(type == XFS_DQ_USER ||
	       type == XFS_DQ_PROJ ||
	       type == XFS_DQ_GROUP);
	if (ip) {
		ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL));
		ASSERT(xfs_inode_dquot(ip, type) == NULL);
	}
#endif

restart:
	mutex_lock(&qi->qi_tree_lock);
	dqp = radix_tree_lookup(tree, id);
	if (dqp) {
		xfs_dqlock(dqp);
		if (dqp->dq_flags & XFS_DQ_FREEING) {
			xfs_dqunlock(dqp);
			mutex_unlock(&qi->qi_tree_lock);
			trace_xfs_dqget_freeing(dqp);
			delay(1);
			goto restart;
		}

		dqp->q_nrefs++;
		mutex_unlock(&qi->qi_tree_lock);

		trace_xfs_dqget_hit(dqp);
		XFS_STATS_INC(xs_qm_dqcachehits);
		*O_dqpp = dqp;
		return 0;
	}
	mutex_unlock(&qi->qi_tree_lock);
	XFS_STATS_INC(xs_qm_dqcachemisses);

	/*
	 * Dquot cache miss. We don't want to keep the inode lock across
	 * a (potential) disk read. Also we don't want to deal with the lock
	 * ordering between quotainode and this inode. OTOH, dropping the inode
	 * lock here means dealing with a chown that can happen before
	 * we re-acquire the lock.
	 */
	if (ip)
		xfs_iunlock(ip, XFS_ILOCK_EXCL);

	error = xfs_qm_dqread(mp, id, type, flags, &dqp);

	if (ip)
		xfs_ilock(ip, XFS_ILOCK_EXCL);

	if (error)
		return error;

	if (ip) {
		/*
		 * A dquot could be attached to this inode by now, since
		 * we had dropped the ilock.
		 */
		if (xfs_this_quota_on(mp, type)) {
			struct xfs_dquot	*dqp1;

			dqp1 = xfs_inode_dquot(ip, type);
			if (dqp1) {
				xfs_qm_dqdestroy(dqp);
				dqp = dqp1;
				xfs_dqlock(dqp);
				goto dqret;
			}
		} else {
			/* inode stays locked on return */
			xfs_qm_dqdestroy(dqp);
			return XFS_ERROR(ESRCH);
		}
	}

	mutex_lock(&qi->qi_tree_lock);
	error = -radix_tree_insert(tree, id, dqp);
	if (unlikely(error)) {
		WARN_ON(error != EEXIST);

		/*
		 * Duplicate found. Just throw away the new dquot and start
		 * over.
		 */
		mutex_unlock(&qi->qi_tree_lock);
		trace_xfs_dqget_dup(dqp);
		xfs_qm_dqdestroy(dqp);
		XFS_STATS_INC(xs_qm_dquot_dups);
		goto restart;
	}

	/*
	 * We return a locked dquot to the caller, with a reference taken
	 */
	xfs_dqlock(dqp);
	dqp->q_nrefs = 1;

	qi->qi_dquots++;
	mutex_unlock(&qi->qi_tree_lock);

 dqret:
	ASSERT((ip == NULL) || xfs_isilocked(ip, XFS_ILOCK_EXCL));
	trace_xfs_dqget_miss(dqp);
	*O_dqpp = dqp;
	return (0);
}