C++ IRELE函数代码示例

/*
 * Called from the vfsops layer.
 */
void
xfs_qm_unmount_quotas(
	xfs_mount_t	*mp)
{
	/*
	 * Release the dquots that root inode, et al might be holding,
	 * before we flush quotas and blow away the quotainfo structure.
	 */
	ASSERT(mp->m_rootip);
	xfs_qm_dqdetach(mp->m_rootip);
	if (mp->m_rbmip)
		xfs_qm_dqdetach(mp->m_rbmip);
	if (mp->m_rsumip)
		xfs_qm_dqdetach(mp->m_rsumip);

	/*
	 * Release the quota inodes.
	 */
	if (mp->m_quotainfo) {
		if (mp->m_quotainfo->qi_uquotaip) {
			IRELE(mp->m_quotainfo->qi_uquotaip);
			mp->m_quotainfo->qi_uquotaip = NULL;
		}
		if (mp->m_quotainfo->qi_gquotaip) {
			IRELE(mp->m_quotainfo->qi_gquotaip);
			mp->m_quotainfo->qi_gquotaip = NULL;
		}
	}
}

STATIC void
xfs_fstrm_free_func(
	unsigned long	ino,
	void		*data)
{
	fstrm_item_t	*item  = (fstrm_item_t *)data;
	xfs_inode_t	*ip = item->ip;

	ASSERT(ip->i_ino == ino);

	xfs_iflags_clear(ip, XFS_IFILESTREAM);

	
	xfs_filestream_put_ag(ip->i_mount, item->ag);

	TRACE_FREE(ip->i_mount, ip, item->pip, item->ag,
		xfs_filestream_peek_ag(ip->i_mount, item->ag));

	IRELE(ip);

	if (item->pip)
		IRELE(item->pip);

	
	kmem_zone_free(item_zone, item);
}

/*
 * Gets called when unmounting a filesystem or when all quotas get
 * turned off.
 * This purges the quota inodes, destroys locks and frees itself.
 */
void
xfs_qm_destroy_quotainfo(
	xfs_mount_t	*mp)
{
	xfs_quotainfo_t *qi;

	qi = mp->m_quotainfo;
	ASSERT(qi != NULL);

	unregister_shrinker(&qi->qi_shrinker);

	if (qi->qi_uquotaip) {
		IRELE(qi->qi_uquotaip);
		qi->qi_uquotaip = NULL; /* paranoia */
	}
	if (qi->qi_gquotaip) {
		IRELE(qi->qi_gquotaip);
		qi->qi_gquotaip = NULL;
	}
	if (qi->qi_pquotaip) {
		IRELE(qi->qi_pquotaip);
		qi->qi_pquotaip = NULL;
	}
	mutex_destroy(&qi->qi_quotaofflock);
	kmem_free(qi);
	mp->m_quotainfo = NULL;
}

int
xfs_qm_scall_trunc_qfiles(
	xfs_mount_t	*mp,
	uint		flags)
{
	int		error = 0, error2 = 0;
	xfs_inode_t	*qip;

	if (!xfs_sb_version_hasquota(&mp->m_sb) || flags == 0) {
		qdprintk("qtrunc flags=%x m_qflags=%x\n", flags, mp->m_qflags);
		return XFS_ERROR(EINVAL);
	}

	if ((flags & XFS_DQ_USER) && mp->m_sb.sb_uquotino != NULLFSINO) {
		error = xfs_iget(mp, NULL, mp->m_sb.sb_uquotino, 0, 0, &qip, 0);
		if (!error) {
			error = xfs_truncate_file(mp, qip);
			IRELE(qip);
		}
	}

	if ((flags & (XFS_DQ_GROUP|XFS_DQ_PROJ)) &&
	    mp->m_sb.sb_gquotino != NULLFSINO) {
		error2 = xfs_iget(mp, NULL, mp->m_sb.sb_gquotino, 0, 0, &qip, 0);
		if (!error2) {
			error2 = xfs_truncate_file(mp, qip);
			IRELE(qip);
		}
	}

	return error ? error : error2;
}

void
libxfs_rtmount_destroy(xfs_mount_t *mp)
{
	if (mp->m_rsumip)
		IRELE(mp->m_rsumip);
	if (mp->m_rbmip)
		IRELE(mp->m_rbmip);
	mp->m_rsumip = mp->m_rbmip = NULL;
}

STATIC struct inode *
xfs_nfs_get_inode(
	struct super_block	*sb,
	u64			ino,
	u32			generation)
 {
 	xfs_mount_t		*mp = XFS_M(sb);
	xfs_inode_t		*ip;
	int			error;

	if (ino == 0)
		return ERR_PTR(-ESTALE);

	error = xfs_iget(mp, NULL, ino, XFS_IGET_UNTRUSTED, 0, &ip);
	if (error) {
		if (error == EINVAL || error == ENOENT)
			error = ESTALE;
		return ERR_PTR(-error);
	}

	if (ip->i_d.di_gen != generation) {
		IRELE(ip);
		return ERR_PTR(-ESTALE);
	}

	return VFS_I(ip);
}

STATIC int
xfs_sync_inode_attr(
	struct xfs_inode	*ip,
	struct xfs_perag	*pag,
	int			flags)
{
	int			error = 0;

	error = xfs_sync_inode_valid(ip, pag);
	if (error)
		return error;

	xfs_ilock(ip, XFS_ILOCK_SHARED);
	if (xfs_inode_clean(ip))
		goto out_unlock;
	if (!xfs_iflock_nowait(ip)) {
		if (!(flags & SYNC_WAIT))
			goto out_unlock;
		xfs_iflock(ip);
	}

	if (xfs_inode_clean(ip)) {
		xfs_ifunlock(ip);
		goto out_unlock;
	}

	error = xfs_iflush(ip, (flags & SYNC_WAIT) ?
			   XFS_IFLUSH_SYNC : XFS_IFLUSH_DELWRI);

 out_unlock:
	xfs_iunlock(ip, XFS_ILOCK_SHARED);
	IRELE(ip);
	return error;
}

STATIC int
xfs_sync_inode_data(
	struct xfs_inode	*ip,
	struct xfs_perag	*pag,
	int			flags)
{
	struct inode		*inode = VFS_I(ip);
	struct address_space *mapping = inode->i_mapping;
	int			error = 0;

	error = xfs_sync_inode_valid(ip, pag);
	if (error)
		return error;

	if (!mapping_tagged(mapping, PAGECACHE_TAG_DIRTY))
		goto out_wait;

	if (!xfs_ilock_nowait(ip, XFS_IOLOCK_SHARED)) {
		if (flags & SYNC_TRYLOCK)
			goto out_wait;
		xfs_ilock(ip, XFS_IOLOCK_SHARED);
	}

	error = xfs_flush_pages(ip, 0, -1, (flags & SYNC_WAIT) ?
				0 : XFS_B_ASYNC, FI_NONE);
	xfs_iunlock(ip, XFS_IOLOCK_SHARED);

 out_wait:
	if (flags & SYNC_WAIT)
		xfs_ioend_wait(ip);
	IRELE(ip);
	return error;
}

/* must be called with pag_ici_lock held and releases it */
int
xfs_sync_inode_valid(
	struct xfs_inode	*ip,
	struct xfs_perag	*pag)
{
	struct inode		*inode = VFS_I(ip);
	int			error = EFSCORRUPTED;

	/* nothing to sync during shutdown */
	if (XFS_FORCED_SHUTDOWN(ip->i_mount))
		goto out_unlock;

	/* avoid new or reclaimable inodes. Leave for reclaim code to flush */
	error = ENOENT;
	if (xfs_iflags_test(ip, XFS_INEW | XFS_IRECLAIMABLE | XFS_IRECLAIM))
		goto out_unlock;

	/* If we can't grab the inode, it must on it's way to reclaim. */
	if (!igrab(inode))
		goto out_unlock;

	if (is_bad_inode(inode)) {
		IRELE(ip);
		goto out_unlock;
	}

	/* inode is valid */
	error = 0;
out_unlock:
	read_unlock(&pag->pag_ici_lock);
	return error;
}

/* xfs_fstrm_free_func(): callback for freeing cached stream items. */
STATIC void
xfs_fstrm_free_func(
	unsigned long	ino,
	void		*data)
{
	fstrm_item_t	*item  = (fstrm_item_t *)data;
	xfs_inode_t	*ip = item->ip;
	int ref;

	ASSERT(ip->i_ino == ino);

	xfs_iflags_clear(ip, XFS_IFILESTREAM);

	/* Drop the reference taken on the AG when the item was added. */
	ref = xfs_filestream_put_ag(ip->i_mount, item->ag);

	ASSERT(ref >= 0);
	TRACE_FREE(ip->i_mount, ip, item->pip, item->ag,
		xfs_filestream_peek_ag(ip->i_mount, item->ag));

	/*
	 * _xfs_filestream_update_ag() always takes a reference on the inode
	 * itself, whether it's a file or a directory.  Release it here.
	 * This can result in the inode being freed and so we must
	 * not hold any inode locks when freeing filesstreams objects
	 * otherwise we can deadlock here.
	 */
	IRELE(ip);

	/*
	 * In the case of a regular file, _xfs_filestream_update_ag() also
	 * takes a ref on the parent inode to keep it in-core.  Release that
	 * too.
	 */
	if (item->pip)
		IRELE(item->pip);

	/* Finally, free the memory allocated for the item. */
	kmem_zone_free(item_zone, item);
}

STATIC int
xfs_qm_scall_trunc_qfile(
	struct xfs_mount	*mp,
	xfs_ino_t		ino)
{
	struct xfs_inode	*ip;
	struct xfs_trans	*tp;
	int			error;

	if (ino == NULLFSINO)
		return 0;

	error = xfs_iget(mp, NULL, ino, 0, 0, &ip);
	if (error)
		return error;

	xfs_ilock(ip, XFS_IOLOCK_EXCL);

	tp = xfs_trans_alloc(mp, XFS_TRANS_TRUNCATE_FILE);
	error = xfs_trans_reserve(tp, 0, XFS_ITRUNCATE_LOG_RES(mp), 0,
				  XFS_TRANS_PERM_LOG_RES,
				  XFS_ITRUNCATE_LOG_COUNT);
	if (error) {
		xfs_trans_cancel(tp, 0);
		xfs_iunlock(ip, XFS_IOLOCK_EXCL);
		goto out_put;
	}

	xfs_ilock(ip, XFS_ILOCK_EXCL);
	xfs_trans_ijoin(tp, ip, 0);

	ip->i_d.di_size = 0;
	xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);

	error = xfs_itruncate_extents(&tp, ip, XFS_DATA_FORK, 0);
	if (error) {
		xfs_trans_cancel(tp, XFS_TRANS_RELEASE_LOG_RES |
				     XFS_TRANS_ABORT);
		goto out_unlock;
	}

	ASSERT(ip->i_d.di_nextents == 0);

	xfs_trans_ichgtime(tp, ip, XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG);
	error = xfs_trans_commit(tp, XFS_TRANS_RELEASE_LOG_RES);

out_unlock:
	xfs_iunlock(ip, XFS_ILOCK_EXCL | XFS_IOLOCK_EXCL);
out_put:
	IRELE(ip);
	return error;
}

STATIC int
xfs_inode_ag_walk_grab(
	struct xfs_inode	*ip)
{
	struct inode		*inode = VFS_I(ip);

	ASSERT(rcu_read_lock_held());

	/*
	 * check for stale RCU freed inode
	 *
	 * If the inode has been reallocated, it doesn't matter if it's not in
	 * the AG we are walking - we are walking for writeback, so if it
	 * passes all the "valid inode" checks and is dirty, then we'll write
	 * it back anyway.  If it has been reallocated and still being
	 * initialised, the XFS_INEW check below will catch it.
	 */
	spin_lock(&ip->i_flags_lock);
	if (!ip->i_ino)
		goto out_unlock_noent;

	/* avoid new or reclaimable inodes. Leave for reclaim code to flush */
	if (__xfs_iflags_test(ip, XFS_INEW | XFS_IRECLAIMABLE | XFS_IRECLAIM))
		goto out_unlock_noent;
	spin_unlock(&ip->i_flags_lock);

	/* nothing to sync during shutdown */
	if (XFS_FORCED_SHUTDOWN(ip->i_mount))
		return EFSCORRUPTED;

	/* If we can't grab the inode, it must on it's way to reclaim. */
	if (!igrab(inode))
		return ENOENT;

	if (is_bad_inode(inode)) {
		IRELE(ip);
		return ENOENT;
	}

	/* inode is valid */
	return 0;

out_unlock_noent:
	spin_unlock(&ip->i_flags_lock);
	return ENOENT;
}

/*
 * "Is this a cached inode that's also allocated?"
 *
 * Look up an inode by number in the given file system.  If the inode is
 * in cache and isn't in purgatory, return 1 if the inode is allocated
 * and 0 if it is not.  For all other cases (not in cache, being torn
 * down, etc.), return a negative error code.
 *
 * The caller has to prevent inode allocation and freeing activity,
 * presumably by locking the AGI buffer.   This is to ensure that an
 * inode cannot transition from allocated to freed until the caller is
 * ready to allow that.  If the inode is in an intermediate state (new,
 * reclaimable, or being reclaimed), -EAGAIN will be returned; if the
 * inode is not in the cache, -ENOENT will be returned.  The caller must
 * deal with these scenarios appropriately.
 *
 * This is a specialized use case for the online scrubber; if you're
 * reading this, you probably want xfs_iget.
 */
int
xfs_icache_inode_is_allocated(
	struct xfs_mount	*mp,
	struct xfs_trans	*tp,
	xfs_ino_t		ino,
	bool			*inuse)
{
	struct xfs_inode	*ip;
	int			error;

	error = xfs_iget(mp, tp, ino, XFS_IGET_INCORE, 0, &ip);
	if (error)
		return error;

	*inuse = !!(VFS_I(ip)->i_mode);
	IRELE(ip);
	return 0;
}

/*
 * Unlock the inode associated with the inode log item.
 * Clear the fields of the inode and inode log item that
 * are specific to the current transaction.  If the
 * hold flags is set, do not unlock the inode.
 */
STATIC void
xfs_inode_item_unlock(
    struct xfs_log_item	*lip)
{
    struct xfs_inode_log_item *iip = INODE_ITEM(lip);
    struct xfs_inode	*ip = iip->ili_inode;
    unsigned short		lock_flags;

    ASSERT(iip->ili_inode->i_itemp != NULL);
    ASSERT(xfs_isilocked(iip->ili_inode, XFS_ILOCK_EXCL));

    /*
     * Clear the transaction pointer in the inode.
     */
    ip->i_transp = NULL;

    /*
     * If the inode needed a separate buffer with which to log
     * its extents, then free it now.
     */
    if (iip->ili_extents_buf != NULL) {
        ASSERT(ip->i_d.di_format == XFS_DINODE_FMT_EXTENTS);
        ASSERT(ip->i_d.di_nextents > 0);
        ASSERT(iip->ili_format.ilf_fields & XFS_ILOG_DEXT);
        ASSERT(ip->i_df.if_bytes > 0);
        kmem_free(iip->ili_extents_buf);
        iip->ili_extents_buf = NULL;
    }
    if (iip->ili_aextents_buf != NULL) {
        ASSERT(ip->i_d.di_aformat == XFS_DINODE_FMT_EXTENTS);
        ASSERT(ip->i_d.di_anextents > 0);
        ASSERT(iip->ili_format.ilf_fields & XFS_ILOG_AEXT);
        ASSERT(ip->i_afp->if_bytes > 0);
        kmem_free(iip->ili_aextents_buf);
        iip->ili_aextents_buf = NULL;
    }

    lock_flags = iip->ili_lock_flags;
    iip->ili_lock_flags = 0;
    if (lock_flags) {
        xfs_iunlock(iip->ili_inode, lock_flags);
        IRELE(iip->ili_inode);
    }
}

/*
 * Find the right allocation group for a file, either by finding an
 * existing file stream or creating a new one.
 *
 * Returns NULLAGNUMBER in case of an error.
 */
xfs_agnumber_t
xfs_filestream_lookup_ag(
	struct xfs_inode	*ip)
{
	struct xfs_mount	*mp = ip->i_mount;
	struct xfs_inode	*pip = NULL;
	xfs_agnumber_t		startag, ag = NULLAGNUMBER;
	struct xfs_mru_cache_elem *mru;

	ASSERT(S_ISREG(ip->i_d.di_mode));

	pip = xfs_filestream_get_parent(ip);
	if (!pip)
		goto out;

	mru = xfs_mru_cache_lookup(mp->m_filestream, pip->i_ino);
	if (mru) {
		ag = container_of(mru, struct xfs_fstrm_item, mru)->ag;
		xfs_mru_cache_done(mp->m_filestream);

		trace_xfs_filestream_lookup(ip, ag);
		goto out;
	}

	/*
	 * Set the starting AG using the rotor for inode32, otherwise
	 * use the directory inode's AG.
	 */
	if (mp->m_flags & XFS_MOUNT_32BITINODES) {
		xfs_agnumber_t	 rotorstep = xfs_rotorstep;
		startag = (mp->m_agfrotor / rotorstep) % mp->m_sb.sb_agcount;
		mp->m_agfrotor = (mp->m_agfrotor + 1) %
		                 (mp->m_sb.sb_agcount * rotorstep);
	} else
		startag = XFS_INO_TO_AGNO(mp, pip->i_ino);

	if (xfs_filestream_pick_ag(pip, startag, &ag, 0, 0))
		ag = NULLAGNUMBER;
out:
	IRELE(pip);
	return ag;
}