iomap: Handle memory allocation failure in readahead (457df33e) · Commits · 戴 / test

bio_alloc() can fail when we use GFP_NORETRY. If it does, allocate a bio large enough for a single page like mpage_readpages() does. Signed-off-by:

fs/iomap/buffered-io.c

+8 −0

Original line number	Diff line number	Diff line
		@@ -302,6 +302,7 @@ iomap_readpage_actor(struct inode inode, loff_t pos, loff_t length, void data,

		if (!ctx->bio \|\| !is_contig \|\| bio_full(ctx->bio, plen)) {
		gfp_t gfp = mapping_gfp_constraint(page->mapping, GFP_KERNEL);
		gfp_t orig_gfp = gfp;
		int nr_vecs = (length + PAGE_SIZE - 1) >> PAGE_SHIFT;

		if (ctx->bio)
		@@ -310,6 +311,13 @@ iomap_readpage_actor(struct inode inode, loff_t pos, loff_t length, void data,
		if (ctx->is_readahead) /* same as readahead_gfp_mask */
		gfp \|= __GFP_NORETRY \| __GFP_NOWARN;
		ctx->bio = bio_alloc(gfp, min(BIO_MAX_PAGES, nr_vecs));
		/*
		* If the bio_alloc fails, try it again for a single page to
		* avoid having to deal with partial page reads. This emulates
		* what do_mpage_readpage does.
		*/
		if (!ctx->bio)
		ctx->bio = bio_alloc(orig_gfp, 1);
		ctx->bio->bi_opf = REQ_OP_READ;
		if (ctx->is_readahead)
		ctx->bio->bi_opf \|= REQ_RAHEAD;