ext4: bio_alloc with __GFP_DIRECT_RECLAIM never fails (5500221e) · Commits · 戴 / test

fs/ext4/page-io.c

+22 −35

Original line number	Diff line number	Diff line
		@@ -394,14 +394,16 @@ void ext4_io_submit_init(struct ext4_io_submit *io,
		io->io_end = NULL;
		}

		static int io_submit_init_bio(struct ext4_io_submit *io,
		static void io_submit_init_bio(struct ext4_io_submit *io,
		struct buffer_head *bh)
		{
		struct bio *bio;

		/*
		* bio_alloc will _always_ be able to allocate a bio if
		* __GFP_DIRECT_RECLAIM is set, see comments for bio_alloc_bioset().
		*/
		bio = bio_alloc(GFP_NOIO, BIO_MAX_PAGES);
		if (!bio)
		return -ENOMEM;
		bio->bi_iter.bi_sector = bh->b_blocknr * (bh->b_size >> 9);
		bio_set_dev(bio, bh->b_bdev);
		bio->bi_end_io = ext4_end_bio;
		@@ -409,10 +411,9 @@ static int io_submit_init_bio(struct ext4_io_submit *io,
		io->io_bio = bio;
		io->io_next_block = bh->b_blocknr;
		wbc_init_bio(io->io_wbc, bio);
		return 0;
		}

		static int io_submit_add_bh(struct ext4_io_submit *io,
		static void io_submit_add_bh(struct ext4_io_submit *io,
		struct inode *inode,
		struct page *page,
		struct buffer_head *bh)
		@@ -424,9 +425,7 @@ submit_and_retry:
		ext4_io_submit(io);
		}
		if (io->io_bio == NULL) {
		ret = io_submit_init_bio(io, bh);
		if (ret)
		return ret;
		io_submit_init_bio(io, bh);
		io->io_bio->bi_write_hint = inode->i_write_hint;
		}
		ret = bio_add_page(io->io_bio, page, bh->b_size, bh_offset(bh));
		@@ -434,7 +433,6 @@ submit_and_retry:
		goto submit_and_retry;
		wbc_account_cgroup_owner(io->io_wbc, page, bh->b_size);
		io->io_next_block++;
		return 0;
		}

		int ext4_bio_write_page(struct ext4_io_submit *io,
		@@ -527,8 +525,14 @@ int ext4_bio_write_page(struct ext4_io_submit *io,
		gfp_flags \|= __GFP_NOFAIL;
		goto retry_encrypt;
		}
		bounce_page = NULL;
		goto out;

		printk_ratelimited(KERN_ERR "%s: ret = %d\n", __func__, ret);
		redirty_page_for_writepage(wbc, page);
		do {
		clear_buffer_async_write(bh);
		bh = bh->b_this_page;
		} while (bh != head);
		goto unlock;
		}
		}

		@@ -536,30 +540,13 @@ int ext4_bio_write_page(struct ext4_io_submit *io,
		do {
		if (!buffer_async_write(bh))
		continue;
		ret = io_submit_add_bh(io, inode, bounce_page ?: page, bh);
		if (ret) {
		/*
		* We only get here on ENOMEM. Not much else
		* we can do but mark the page as dirty, and
		* better luck next time.
		*/
		break;
		}
		io_submit_add_bh(io, inode,
		bounce_page ? bounce_page : page, bh);
		nr_submitted++;
		clear_buffer_dirty(bh);
		} while ((bh = bh->b_this_page) != head);

		/* Error stopped previous loop? Clean up buffers... */
		if (ret) {
		out:
		fscrypt_free_bounce_page(bounce_page);
		printk_ratelimited(KERN_ERR "%s: ret = %d\n", __func__, ret);
		redirty_page_for_writepage(wbc, page);
		do {
		clear_buffer_async_write(bh);
		bh = bh->b_this_page;
		} while (bh != head);
		}
		unlock:
		unlock_page(page);
		/* Nothing submitted - we have to end page writeback */
		if (!nr_submitted)

fs/ext4/readpage.c

+4 −2

Original line number	Diff line number	Diff line
		@@ -360,10 +360,12 @@ int ext4_mpage_readpages(struct address_space *mapping,
		if (bio == NULL) {
		struct bio_post_read_ctx *ctx;

		/*
		* bio_alloc will _always_ be able to allocate a bio if
		* __GFP_DIRECT_RECLAIM is set, see bio_alloc_bioset().
		*/
		bio = bio_alloc(GFP_KERNEL,
		min_t(int, nr_pages, BIO_MAX_PAGES));
		if (!bio)
		goto set_error_page;
		ctx = get_bio_post_read_ctx(inode, bio, page->index);
		if (IS_ERR(ctx)) {
		bio_put(bio);

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