From: Chandan Babu R <chandanrlinux@gmail.com> mainline inclusion from mainline-v5.12-rc1 commit 5f1d5bbfb2e674052a9fe542f53678978af20770 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/?i... -------------------------------- Moving an extent to data fork can cause a sub-interval of an existing extent to be unmapped. This will increase extent count by 1. Mapping in the new extent can increase the extent count by 1 again i.e. | Old extent | New extent | Old extent | Hence number of extents increases by 2. Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Allison Henderson <allison.henderson@oracle.com> Signed-off-by: Chandan Babu R <chandanrlinux@gmail.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Yu Kuai <yukuai3@huawei.com> Signed-off-by: Guo Xuenan <guoxuenan@huawei.com> Reviewed-by: Zhang Yi <yi.zhang@huawei.com> Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com> --- fs/xfs/libxfs/xfs_inode_fork.h | 9 +++++++++ fs/xfs/xfs_reflink.c | 5 +++++ 2 files changed, 14 insertions(+) diff --git a/fs/xfs/libxfs/xfs_inode_fork.h b/fs/xfs/libxfs/xfs_inode_fork.h index 917e289ad962..c8f279edc5c1 100644 --- a/fs/xfs/libxfs/xfs_inode_fork.h +++ b/fs/xfs/libxfs/xfs_inode_fork.h @@ -79,6 +79,15 @@ struct xfs_ifork { #define XFS_IEXT_WRITE_UNWRITTEN_CNT (2) +/* + * Moving an extent to data fork can cause a sub-interval of an existing extent + * to be unmapped. This will increase extent count by 1. Mapping in the new + * extent can increase the extent count by 1 again i.e. + * | Old extent | New extent | Old extent | + * Hence number of extents increases by 2. + */ +#define XFS_IEXT_REFLINK_END_COW_CNT (2) + /* * Fork handling. */ diff --git a/fs/xfs/xfs_reflink.c b/fs/xfs/xfs_reflink.c index 6c8492b16c7b..b85b249df989 100644 --- a/fs/xfs/xfs_reflink.c +++ b/fs/xfs/xfs_reflink.c @@ -615,6 +615,11 @@ xfs_reflink_end_cow_extent( xfs_ilock(ip, XFS_ILOCK_EXCL); xfs_trans_ijoin(tp, ip, 0); + error = xfs_iext_count_may_overflow(ip, XFS_DATA_FORK, + XFS_IEXT_REFLINK_END_COW_CNT); + if (error) + goto out_cancel; + /* * In case of racing, overlapping AIO writes no COW extents might be * left by the time I/O completes for the loser of the race. In that -- 2.20.1