xfs: Check for extent overflow when adding/removing xattrs

mainline inclusion
from mainline-v5.12-rc1
commit 3a19bb14
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=3a19bb147c72d2e9b77137bf5130b9cfb50a5eef

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

Adding/removing an xattr can cause XFS_DA_NODE_MAXDEPTH extents to be
added. One extra extent for dabtree in case a local attr is large enough
to cause a double split.  It can also cause extent count to increase
proportional to the size of a remote xattr's value.
Reviewed-by: NDarrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NAllison Henderson <allison.henderson@oracle.com>
Signed-off-by: NChandan Babu R <chandanrlinux@gmail.com>
Signed-off-by: NDarrick 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: NYu Kuai <yukuai3@huawei.com>
Signed-off-by: NGuo Xuenan <guoxuenan@huawei.com>
Reviewed-by: NZhang Yi <yi.zhang@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

fs/xfs/libxfs/xfs_attr.c

@@ -396,6 +396,7 @@ xfs_attr_set(
 	struct xfs_trans_res	tres;
 	bool			rsvd = (args->attr_filter & XFS_ATTR_ROOT);
 	int			error, local;
+	int			rmt_blks = 0;
 	unsigned int		total;
 
 	if (XFS_FORCED_SHUTDOWN(dp->i_mount))
@@ -442,11 +443,15 @@ xfs_attr_set(
 		tres.tr_logcount = XFS_ATTRSET_LOG_COUNT;
 		tres.tr_logflags = XFS_TRANS_PERM_LOG_RES;
 		total = args->total;
+
+		if (!local)
+			rmt_blks = xfs_attr3_rmt_blocks(mp, args->valuelen);
 	} else {
 		XFS_STATS_INC(mp, xs_attr_remove);
 
 		tres = M_RES(mp)->tr_attrrm;
 		total = XFS_ATTRRM_SPACE_RES(mp);
+		rmt_blks = xfs_attr3_rmt_blocks(mp, XFS_XATTR_SIZE_MAX);
 	}
 
 	/*
@@ -457,6 +462,13 @@ xfs_attr_set(
 	if (error)
 		return error;
 
+	if (args->value || xfs_inode_hasattr(dp)) {
+		error = xfs_iext_count_may_overflow(dp, XFS_ATTR_FORK,
+				XFS_IEXT_ATTR_MANIP_CNT(rmt_blks));
+		if (error)
+			goto out_trans_cancel;
+	}
+
 	if (args->value) {
 		error = xfs_has_attr(args);
 		if (error == -EEXIST && (args->attr_flags & XATTR_CREATE))

fs/xfs/libxfs/xfs_inode_fork.h

@@ -60,6 +60,16 @@ struct xfs_ifork {
 #define XFS_IEXT_DIR_MANIP_CNT(mp) \
 	((XFS_DA_NODE_MAXDEPTH + 1 + 1) * (mp)->m_dir_geo->fsbcount)
 
+/*
+ * Adding/removing an xattr can cause XFS_DA_NODE_MAXDEPTH extents to
+ * be added. One extra extent for dabtree in case a local attr is
+ * large enough to cause a double split.  It can also cause extent
+ * count to increase proportional to the size of a remote xattr's
+ * value.
+ */
+#define XFS_IEXT_ATTR_MANIP_CNT(rmt_blks) \
+	(XFS_DA_NODE_MAXDEPTH + max(1, rmt_blks))
+
 /*
  * Fork handling.
  */