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Commit d7ebeff9 authored by Chao Yu's avatar Chao Yu Committed by Jaegeuk Kim
Browse files

f2fs: fix panic of IO alignment feature 

Since 07173c3ec276 ("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: default avatarChao Yu <yuchao0@huawei.com>
Signed-off-by: default avatarJaegeuk Kim <jaegeuk@kernel.org>
parent 6f1c7fb7

fs/f2fs/data.c

+10 −0
Original line number Diff line number Diff line
@@ -527,6 +527,16 @@ 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
@@ -3217,7 +3217,7 @@ static int f2fs_fill_super(struct super_block *sb, void *data, int silent) 
	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)