f2fs: fix panic of IO alignment feature (c72db71e) · Commits · 戴 / test

Since ("block: enable multipage bvecs"), one bio vector can store multi pages, so that we can not calculate max IO size of bio as PAGE_SIZE * bio->bi_max_vecs. However IO alignment feature of f2fs always has that assumption, so finally, it may cause panic during IO submission as below stack. kernel BUG at fs/f2fs/data.c:317! RIP: 0010:__submit_merged_bio+0x8b0/0x8c0 Call Trace: f2fs_submit_page_write+0x3cd/0xdd0 do_write_page+0x15d/0x360 f2fs_outplace_write_data+0xd7/0x210 f2fs_do_write_data_page+0x43b/0xf30 __write_data_page+0xcf6/0x1140 f2fs_write_cache_pages+0x3ba/0xb40 f2fs_write_data_pages+0x3dd/0x8b0 do_writepages+0xbb/0x1e0 __writeback_single_inode+0xb6/0x800 writeback_sb_inodes+0x441/0x910 wb_writeback+0x261/0x650 wb_workfn+0x1f9/0x7a0 process_one_work+0x503/0x970 worker_thread+0x7d/0x820 kthread+0x1ad/0x210 ret_from_fork+0x35/0x40 This patch adds one extra condition to check left space in bio while trying merging page to bio, to avoid panic. This bug was reported in bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=204043 Signed-off-by:

Chao Yu <yuchao0@huawei.com> Signed-off-by:

Jaegeuk Kim <jaegeuk@kernel.org>

fs/f2fs/data.c

+10 −0

Original line number	Diff line number	Diff line
		@@ -503,6 +503,16 @@ static bool io_is_mergeable(struct f2fs_sb_info sbi, struct bio bio,
		block_t last_blkaddr,
		block_t cur_blkaddr)
		{
		if (F2FS_IO_ALIGNED(sbi) && (fio->type == DATA \|\| fio->type == NODE)) {
		unsigned int filled_blocks =
		F2FS_BYTES_TO_BLK(bio->bi_iter.bi_size);
		unsigned int io_size = F2FS_IO_SIZE(sbi);
		unsigned int left_vecs = bio->bi_max_vecs - bio->bi_vcnt;

		/* IOs in bio is aligned and left space of vectors is not enough */
		if (!(filled_blocks % io_size) && left_vecs < io_size)
		return false;
		}
		if (!page_is_mergeable(sbi, bio, last_blkaddr, cur_blkaddr))
		return false;
		return io_type_is_mergeable(io, fio);

fs/f2fs/super.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -3202,7 +3202,7 @@ try_onemore:
		if (err)
		goto free_bio_info;

		if (F2FS_IO_SIZE(sbi) > 1) {
		if (F2FS_IO_ALIGNED(sbi)) {
		sbi->write_io_dummy =
		mempool_create_page_pool(2 * (F2FS_IO_SIZE(sbi) - 1), 0);
		if (!sbi->write_io_dummy) {

include/linux/f2fs_fs.h

+1 −0

Original line number	Diff line number	Diff line
		@@ -41,6 +41,7 @@
		#define F2FS_IO_SIZE_BYTES(sbi) (1 << (F2FS_OPTION(sbi).write_io_size_bits + 12)) /* B */
		#define F2FS_IO_SIZE_BITS(sbi) (F2FS_OPTION(sbi).write_io_size_bits) /* power of 2 */
		#define F2FS_IO_SIZE_MASK(sbi) (F2FS_IO_SIZE(sbi) - 1)
		#define F2FS_IO_ALIGNED(sbi) (F2FS_IO_SIZE(sbi) > 1)

		/* This flag is used by node and meta inodes, and by recovery */
		#define GFP_F2FS_ZERO (GFP_NOFS \| __GFP_ZERO)

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