From: Chandan Babu R <chandanrlinux@gmail.com> mainline inclusion from mainline-v5.12-rc4 commit b6785e279d53ca5c4fa6be1146e85000870d73ef category: bugfix bugzilla: 188220, https://gitee.com/openeuler/kernel/issues/I4KIAO CVE: NA Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... -------------------------------- The incore data fork of an inode stores the bmap btree root node as 'struct xfs_btree_block'. However, the ondisk version of the inode stores the bmap btree root node as a 'struct xfs_bmdr_block'. xfs_bmap_add_attrfork_btree() checks if the btree root node fits inside the data fork of the inode. However, it incorrectly uses 'struct xfs_btree_block' to compute the size of the bmap btree root node. Since size of 'struct xfs_btree_block' is larger than that of 'struct xfs_bmdr_block', xfs_bmap_add_attrfork_btree() could end up unnecessarily demoting the current root node as the child of newly allocated root node. This commit optimizes space usage by modifying xfs_bmap_add_attrfork_btree() to use 'struct xfs_bmdr_block' to check if the bmap btree root node fits inside the data fork of the inode. Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Chandan Babu R <chandanrlinux@gmail.com> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Signed-off-by: Darrick J. Wong <djwong@kernel.org> Conflicts: fs/xfs/libxfs/xfs_bmap.c Signed-off-by: Long Li <leo.lilong@huawei.com> Reviewed-by: Zhang Yi <yi.zhang@huawei.com> Signed-off-by: Jialin Zhang <zhangjialin11@huawei.com> --- fs/xfs/libxfs/xfs_bmap.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/fs/xfs/libxfs/xfs_bmap.c b/fs/xfs/libxfs/xfs_bmap.c index 02ce08745347..ea5a9a93948c 100644 --- a/fs/xfs/libxfs/xfs_bmap.c +++ b/fs/xfs/libxfs/xfs_bmap.c @@ -926,13 +926,15 @@ xfs_bmap_add_attrfork_btree( xfs_inode_t *ip, /* incore inode pointer */ int *flags) /* inode logging flags */ { + struct xfs_btree_block *block = ip->i_df.if_broot; xfs_btree_cur_t *cur; /* btree cursor */ int error; /* error return value */ xfs_mount_t *mp; /* file system mount struct */ int stat; /* newroot status */ mp = ip->i_mount; - if (ip->i_df.if_broot_bytes <= xfs_inode_data_fork_size(ip)) + + if (XFS_BMAP_BMDR_SPACE(block) <= xfs_inode_data_fork_size(ip)) *flags |= XFS_ILOG_DBROOT; else { cur = xfs_bmbt_init_cursor(mp, tp, ip, XFS_DATA_FORK); -- 2.25.1