On Sat, Oct 25, 2025 at 05:45:29AM +0100, Matthew Wilcox wrote:

On Sat, Oct 25, 2025 at 11:22:18AM +0800, libaokun@huaweicloud.com wrote:

quoted

+	while (1) {
+		folio = __filemap_get_folio(mapping, index, fgp_flags,
+					    gfp & ~__GFP_NOFAIL);
+		if (!IS_ERR(folio) || !(gfp & __GFP_NOFAIL))
+			return folio;
+
+		if (PTR_ERR(folio) != -ENOMEM && PTR_ERR(folio) != -EAGAIN)
+			return folio;
+
+		memalloc_retry_wait(gfp);
+	}

No, absolutely not.  We're not having open-coded GFP_NOFAIL semantics.
The right way forward is for ext4 to use iomap, not for buffer heads
to support large block sizes.

Seconded.

--D