block: add a bi_error field to struct bio
Currently we have two different ways to signal an I/O error on a BIO:
(1) by clearing the BIO_UPTODATE flag
(2) by returning a Linux errno value to the bi_end_io callback
The first one has the drawback of only communicating a single possible
error (-EIO), and the second one has the drawback of not beeing persistent
when bios are queued up, and are not passed along from child to parent
bio in the ever more popular chaining scenario. Having both mechanisms
available has the additional drawback of utterly confusing driver authors
and introducing bugs where various I/O submitters only deal with one of
them, and the others have to add boilerplate code to deal with both kinds
of error returns.
So add a new bi_error field to store an errno value directly in struct
bio and remove the existing mechanisms to clean all this up.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: NeilBrown <neilb@suse.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
diff --git a/fs/btrfs/check-integrity.c b/fs/btrfs/check-integrity.c
index ce7dec8..541fbfa 100644
--- a/fs/btrfs/check-integrity.c
+++ b/fs/btrfs/check-integrity.c
@@ -343,7 +343,7 @@
struct btrfsic_state *state,
struct btrfsic_block *const block,
struct btrfs_super_block *const super_hdr);
-static void btrfsic_bio_end_io(struct bio *bp, int bio_error_status);
+static void btrfsic_bio_end_io(struct bio *bp);
static void btrfsic_bh_end_io(struct buffer_head *bh, int uptodate);
static int btrfsic_is_block_ref_by_superblock(const struct btrfsic_state *state,
const struct btrfsic_block *block,
@@ -2207,7 +2207,7 @@
goto again;
}
-static void btrfsic_bio_end_io(struct bio *bp, int bio_error_status)
+static void btrfsic_bio_end_io(struct bio *bp)
{
struct btrfsic_block *block = (struct btrfsic_block *)bp->bi_private;
int iodone_w_error;
@@ -2215,7 +2215,7 @@
/* mutex is not held! This is not save if IO is not yet completed
* on umount */
iodone_w_error = 0;
- if (bio_error_status)
+ if (bp->bi_error)
iodone_w_error = 1;
BUG_ON(NULL == block);
@@ -2230,7 +2230,7 @@
BTRFSIC_PRINT_MASK_END_IO_BIO_BH))
printk(KERN_INFO
"bio_end_io(err=%d) for %c @%llu (%s/%llu/%d)\n",
- bio_error_status,
+ bp->bi_error,
btrfsic_get_block_type(dev_state->state, block),
block->logical_bytenr, dev_state->name,
block->dev_bytenr, block->mirror_num);
@@ -2252,7 +2252,7 @@
block = next_block;
} while (NULL != block);
- bp->bi_end_io(bp, bio_error_status);
+ bp->bi_end_io(bp);
}
static void btrfsic_bh_end_io(struct buffer_head *bh, int uptodate)