Re: [PATCH 2/4] block: bio_check_eod() needs to consider partition

Omar Sandoval
2018-02-26T21:03:08Z

On Mon, Feb 26, 2018 at 08:04:38PM +0800, Jiufei Xue wrote:
> bio_check_eod() should get the capacity of partiton, not the whole
> disk.
>
> Signed-off-by: Jiufei Xue <jiufei.xue@linux.alibaba.com>
> ---
> block/blk-core.c | 16 ++++++++++++----
> 1 file changed, 12 insertions(+), 4 deletions(-)
>
> diff --git a/block/blk-core.c b/block/blk-core.c
> index 6d82c4f..ef6677d 100644
> --- a/block/blk-core.c
> +++ b/block/blk-core.c
> @@ -2023,7 +2023,7 @@ static blk_qc_t blk_queue_bio(struct request_queue *q, struct bio *bio)
> return BLK_QC_T_NONE;
> }
>
> -static void handle_bad_sector(struct bio *bio)
> +static void handle_bad_sector(struct bio *bio, sector_t maxsector)
> {
> char b[BDEVNAME_SIZE];
>
> @@ -2031,7 +2031,7 @@ static void handle_bad_sector(struct bio *bio)
> printk(KERN_INFO "%s: rw=%d, want=%Lu, limit=%Lu\n",
> bio_devname(bio, b), bio->bi_opf,
> (unsigned long long)bio_end_sector(bio),
> - (long long)get_capacity(bio->bi_disk));
> + (long long)maxsector);
> }
>
> #ifdef CONFIG_FAIL_MAKE_REQUEST
> @@ -2131,12 +2131,20 @@ static inline int blk_partition_remap(struct bio *bio)
> static inline int bio_check_eod(struct bio *bio, unsigned int nr_sectors)
> {
> sector_t maxsector;
> + struct hd_struct *part;
>
> if (!nr_sectors)
> return 0;
>
> /* Test device or partition size, when known. */
> - maxsector = get_capacity(bio->bi_disk);
> + rcu_read_lock();
> + part = __disk_get_part(bio->bi_disk, bio->bi_partno);
> + if (part)
> + maxsector = part_nr_sects_read(part);
> + else
> + maxsector = get_capacity(bio->bi_disk);

This case means that bio->bi_partno was invalid, right? Shouldn't this
be an error? I see that this is copied from guard_bio_eod(), but that
serves a slightly different purpose.

> + rcu_read_unlock();
> +
> if (maxsector) {
> sector_t sector = bio->bi_iter.bi_sector;
>
> @@ -2146,7 +2154,7 @@ static inline int bio_check_eod(struct bio *bio, unsigned int nr_sectors)
> * without checking the size of the device, e.g., when
> * mounting a device.
> */
> - handle_bad_sector(bio);
> + handle_bad_sector(bio, maxsector);
> return 1;
> }
> }
> --
> 1.9.4
>
>