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Commit ff3d8b9c authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Darrick J. Wong
Browse files

xfs: don't block on the ilock for RWF_NOWAIT 



Fix xfs_file_iomap_begin to trylock the ilock if IOMAP_NOWAIT is passed,
so that we don't block io_submit callers.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarDave Chinner <dchinner@redhat.com>
Reviewed-by: default avatarDarrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: default avatarDarrick J. Wong <darrick.wong@oracle.com>
parent af5b5afe

fs/xfs/xfs_iomap.c

+19 −8
Original line number Diff line number Diff line
@@ -970,6 +970,15 @@ static inline bool need_excl_ilock(struct xfs_inode *ip, unsigned flags) 
	 */

	if (xfs_is_reflink_inode(ip) && (flags & (IOMAP_WRITE | IOMAP_ZERO)))

		return true;



	/*

	 * Extents not yet cached requires exclusive access, don't block.

	 * This is an opencoded xfs_ilock_data_map_shared() to cater for the

	 * non-blocking behaviour.

	 */

	if (ip->i_d.di_format == XFS_DINODE_FMT_BTREE &&

	    !(ip->i_df.if_flags & XFS_IFEXTENTS))

		return true;

	return false;

}
@@ -998,16 +1007,18 @@ xfs_file_iomap_begin( 
		return xfs_file_iomap_begin_delay(inode, offset, length, iomap);

	}



	if (need_excl_ilock(ip, flags)) {

	if (need_excl_ilock(ip, flags))

		lockmode = XFS_ILOCK_EXCL;

		xfs_ilock(ip, XFS_ILOCK_EXCL);

	} else {

		lockmode = xfs_ilock_data_map_shared(ip);

	}

	else

		lockmode = XFS_ILOCK_SHARED;



	if ((flags & IOMAP_NOWAIT) && !(ip->i_df.if_flags & XFS_IFEXTENTS)) {

		error = -EAGAIN;

		goto out_unlock;

	if (flags & IOMAP_NOWAIT) {

		if (!(ip->i_df.if_flags & XFS_IFEXTENTS))

			return -EAGAIN;

		if (!xfs_ilock_nowait(ip, lockmode))

			return -EAGAIN;

	} else {

		xfs_ilock(ip, lockmode);

	}



	ASSERT(offset <= mp->m_super->s_maxbytes);