Re: FIle copy to FAT FS on NVDIMM hits BUG_ON at fs/buffer.c:3305!

"Kani, Toshimitsu" <toshi.kani(a)hpe.com&gt; writes: The locking of this path seems to be broken. The guy familiar to bdev_write_page() path will made real fix though, The following patch should be explaining enough what is wrong. In short, clean_buffers() must be called before unlocking lock_page(). Signed-off-by: OGAWA Hirofumi <hirofumi(a)mail.parknet.co.jp&gt; --- fs/block_dev.c | 2 -- fs/mpage.c | 1 + mm/page_io.c | 1 + 3 files changed, 2 insertions(+), 2 deletions(-) diff -puN fs/mpage.c~bdev_write_page-fix fs/mpage.c --- linux/fs/mpage.c~bdev_write_page-fix 2017-07-26 18:05:53.078204737 +0900 +++ linux-hirofumi/fs/mpage.c 2017-07-26 18:07:03.960043665 +0900 @@ -605,6 +605,7 @@ alloc_new: if (!bdev_write_page(bdev, blocks[0] << (blkbits - 9), page, wbc)) { clean_buffers(page, first_unmapped); + unlock_page(page); goto out; } } diff -puN mm/page_io.c~bdev_write_page-fix mm/page_io.c --- linux/mm/page_io.c~bdev_write_page-fix 2017-07-26 18:06:16.807150810 +0900 +++ linux-hirofumi/mm/page_io.c 2017-07-26 18:06:23.425135771 +0900 @@ -308,6 +308,7 @@ int __swap_writepage(struct page *page, ret = bdev_write_page(sis->bdev, swap_page_sector(page), page, wbc); if (!ret) { + unlock_page(page); count_vm_event(PSWPOUT); return 0; } diff -puN fs/block_dev.c~bdev_write_page-fix fs/block_dev.c --- linux/fs/block_dev.c~bdev_write_page-fix 2017-07-26 18:08:53.490794861 +0900 +++ linux-hirofumi/fs/block_dev.c 2017-07-26 18:08:58.375783767 +0900 @@ -714,8 +714,6 @@ int bdev_write_page(struct block_device result = ops->rw_page(bdev, sector + get_start_sect(bdev), page, true); if (result) end_page_writeback(page); - else - unlock_page(page); blk_queue_exit(bdev->bd_queue); return result; } _ -- OGAWA Hirofumi <hirofumi(a)mail.parknet.co.jp&gt;