Re: [f2fs-dev] [PATCH] f2fs: bio_alloc should never fail

Chao Yu
2019-10-30T08:56:30Z

On 2019/10/30 11:55, Gao Xiang wrote:
> remove such useless code and related fault injection.

Hi Xiang,

Although, there is so many 'nofail' allocation in f2fs, I think we'd better
avoid such allocation as much as possible (now for read path, we may allow to
fail to allocate bio), I suggest to keep the failure path and bio allocation
injection.

It looks bio_alloc() will use its own mempool, which may suffer deadlock
potentially. So how about changing to use bio_alloc_bioset(, , NULL) instead of
bio_alloc()?

Thanks,

>
> Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
> ---
> Documentation/filesystems/f2fs.txt | 1 -
> fs/f2fs/data.c | 6 ++----
> fs/f2fs/f2fs.h | 21 ---------------------
> fs/f2fs/segment.c | 5 +----
> fs/f2fs/super.c | 1 -
> 5 files changed, 3 insertions(+), 31 deletions(-)
>
> diff --git a/Documentation/filesystems/f2fs.txt b/Documentation/filesystems/f2fs.txt
> index 7e1991328473..3477c3e4c08b 100644
> --- a/Documentation/filesystems/f2fs.txt
> +++ b/Documentation/filesystems/f2fs.txt
> @@ -172,7 +172,6 @@ fault_type=%d Support configuring fault injection type, should be
> FAULT_KVMALLOC 0x000000002
> FAULT_PAGE_ALLOC 0x000000004
> FAULT_PAGE_GET 0x000000008
> - FAULT_ALLOC_BIO 0x000000010
> FAULT_ALLOC_NID 0x000000020
> FAULT_ORPHAN 0x000000040
> FAULT_BLOCK 0x000000080
> diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
> index 5755e897a5f0..3b88dcb15de6 100644
> --- a/fs/f2fs/data.c
> +++ b/fs/f2fs/data.c
> @@ -288,7 +288,7 @@ static struct bio *__bio_alloc(struct f2fs_io_info *fio, int npages)
> struct f2fs_sb_info *sbi = fio->sbi;
> struct bio *bio;
>
> - bio = f2fs_bio_alloc(sbi, npages, true);
> + bio = bio_alloc(GFP_NOIO, npages);
>
> f2fs_target_device(sbi, fio->new_blkaddr, bio);
> if (is_read_io(fio->op)) {
> @@ -682,9 +682,7 @@ static struct bio *f2fs_grab_read_bio(struct inode *inode, block_t blkaddr,
> struct bio_post_read_ctx *ctx;
> unsigned int post_read_steps = 0;
>
> - bio = f2fs_bio_alloc(sbi, min_t(int, nr_pages, BIO_MAX_PAGES), false);
> - if (!bio)
> - return ERR_PTR(-ENOMEM);
> + bio = bio_alloc(GFP_KERNEL, min_t(int, nr_pages, BIO_MAX_PAGES));
> f2fs_target_device(sbi, blkaddr, bio);
> bio->bi_end_io = f2fs_read_end_io;
> bio_set_op_attrs(bio, REQ_OP_READ, op_flag);
> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
> index 4024790028aa..40012f874be0 100644
> --- a/fs/f2fs/f2fs.h
> +++ b/fs/f2fs/f2fs.h
> @@ -44,7 +44,6 @@ enum {
> FAULT_KVMALLOC,
> FAULT_PAGE_ALLOC,
> FAULT_PAGE_GET,
> - FAULT_ALLOC_BIO,
> FAULT_ALLOC_NID,
> FAULT_ORPHAN,
> FAULT_BLOCK,
> @@ -2210,26 +2209,6 @@ static inline void *f2fs_kmem_cache_alloc(struct kmem_cache *cachep,
> return entry;
> }
>
> -static inline struct bio *f2fs_bio_alloc(struct f2fs_sb_info *sbi,
> - int npages, bool no_fail)
> -{
> - struct bio *bio;
> -
> - if (no_fail) {
> - /* No failure on bio allocation */
> - bio = bio_alloc(GFP_NOIO, npages);
> - if (!bio)
> - bio = bio_alloc(GFP_NOIO | __GFP_NOFAIL, npages);
> - return bio;
> - }
> - if (time_to_inject(sbi, FAULT_ALLOC_BIO)) {
> - f2fs_show_injection_info(FAULT_ALLOC_BIO);
> - return NULL;
> - }
> -
> - return bio_alloc(GFP_KERNEL, npages);
> -}
> -
> static inline bool is_idle(struct f2fs_sb_info *sbi, int type)
> {
> if (sbi->gc_mode == GC_URGENT)
> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
> index 808709581481..28457c878d0d 100644
> --- a/fs/f2fs/segment.c
> +++ b/fs/f2fs/segment.c
> @@ -552,10 +552,7 @@ static int __submit_flush_wait(struct f2fs_sb_info *sbi,
> struct bio *bio;
> int ret;
>
> - bio = f2fs_bio_alloc(sbi, 0, false);
> - if (!bio)
> - return -ENOMEM;
> -
> + bio = bio_alloc(GFP_KERNEL, 0);
> bio->bi_opf = REQ_OP_WRITE | REQ_SYNC | REQ_PREFLUSH;
> bio_set_dev(bio, bdev);
> ret = submit_bio_wait(bio);
> diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
> index 1443cee15863..51945dd27f00 100644
> --- a/fs/f2fs/super.c
> +++ b/fs/f2fs/super.c
> @@ -44,7 +44,6 @@ const char *f2fs_fault_name[FAULT_MAX] = {
> [FAULT_KVMALLOC] = "kvmalloc",
> [FAULT_PAGE_ALLOC] = "page alloc",
> [FAULT_PAGE_GET] = "page get",
> - [FAULT_ALLOC_BIO] = "alloc bio",
> [FAULT_ALLOC_NID] = "alloc nid",
> [FAULT_ORPHAN] = "orphan",
> [FAULT_BLOCK] = "no more block",
>