Commit c354ad22 authored by Chandan Babu R's avatar Chandan Babu R Committed by Zheng Zengkai
Browse files

xfs: Check for extent overflow when writing to unwritten extent 

mainline inclusion
from mainline-v5.12-rc1
commit c442f308
category: bugfix
bugzilla: 187510,https://gitee.com/openeuler/kernel/issues/I4KIAO

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=c442f3086d5a108b7ff086c8ade1923a8f389db5



--------------------------------

A write to a sub-interval of an existing unwritten extent causes
the original extent to be split into 3 extents
i.e. | Unwritten | Real | Unwritten |
Hence extent count can increase by 2.

Reviewed-by: default avatarDarrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarAllison Henderson <allison.henderson@oracle.com>
Signed-off-by: default avatarChandan Babu R <chandanrlinux@gmail.com>
Signed-off-by: default avatarDarrick J. Wong <darrick.wong@oracle.com>

Conflict: commit 3a1af6c3 ("xfs: refactor common
transaction/inode/quota allocation idiom") is backported, which
introduce some conflicts on code context.
Signed-off-by: default avatarYu Kuai <yukuai3@huawei.com>
Signed-off-by: default avatarGuo Xuenan <guoxuenan@huawei.com>
Reviewed-by: default avatarZhang Yi <yi.zhang@huawei.com>
Signed-off-by: default avatarZheng Zengkai <zhengzengkai@huawei.com>
parent a1f6d467

fs/xfs/libxfs/xfs_inode_fork.h

+9 −0
Original line number Diff line number Diff line
@@ -70,6 +70,15 @@ struct xfs_ifork { 
#define XFS_IEXT_ATTR_MANIP_CNT(rmt_blks) \

	(XFS_DA_NODE_MAXDEPTH + max(1, rmt_blks))



/*

 * A write to a sub-interval of an existing unwritten extent causes the original

 * extent to be split into 3 extents

 * i.e. | Unwritten | Real | Unwritten |

 * Hence extent count can increase by 2.

 */

#define XFS_IEXT_WRITE_UNWRITTEN_CNT	(2)





/*

 * Fork handling.

 */

fs/xfs/xfs_iomap.c

+4 −0
Original line number Diff line number Diff line
@@ -545,6 +545,10 @@ xfs_iomap_write_unwritten( 
		if (error)

			return error;



		error = xfs_iext_count_may_overflow(ip, XFS_DATA_FORK,

				XFS_IEXT_WRITE_UNWRITTEN_CNT);

		if (error)

			goto error_on_bmapi_transaction;



		/*

		 * Modify the unwritten extent state of the buffer.