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: Chao Yu <yuch...@huawei.com> --- v2: add IO type check. fs/f2fs/data.c | 10 ++++++++++ fs/f2fs/super.c | 2 +- include/linux/f2fs_fs.h | 1 + 3 files changed, 12 insertions(+), 1 deletion(-) diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c index f1e401f9fc13..1971e59cdedb 100644 --- a/fs/f2fs/data.c +++ b/fs/f2fs/data.c @@ -504,6 +504,16 @@ 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); diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c index d95a681ef7c9..a98e3b93395d 100644 --- a/fs/f2fs/super.c +++ b/fs/f2fs/super.c @@ -3204,7 +3204,7 @@ 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) { diff --git a/include/linux/f2fs_fs.h b/include/linux/f2fs_fs.h index 65559900d4d7..52af9ac164b4 100644 --- a/include/linux/f2fs_fs.h +++ b/include/linux/f2fs_fs.h @@ -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) -- 2.18.0.rc1
