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/raid56.c b/fs/btrfs/raid56.c
index fa72068..0a02e24 100644
--- a/fs/btrfs/raid56.c
+++ b/fs/btrfs/raid56.c
@@ -851,7 +851,7 @@
* this frees the rbio and runs through all the bios in the
* bio_list and calls end_io on them
*/
-static void rbio_orig_end_io(struct btrfs_raid_bio *rbio, int err, int uptodate)
+static void rbio_orig_end_io(struct btrfs_raid_bio *rbio, int err)
{
struct bio *cur = bio_list_get(&rbio->bio_list);
struct bio *next;
@@ -864,9 +864,8 @@
while (cur) {
next = cur->bi_next;
cur->bi_next = NULL;
- if (uptodate)
- set_bit(BIO_UPTODATE, &cur->bi_flags);
- bio_endio(cur, err);
+ cur->bi_error = err;
+ bio_endio(cur);
cur = next;
}
}
@@ -875,9 +874,10 @@
* end io function used by finish_rmw. When we finally
* get here, we've written a full stripe
*/
-static void raid_write_end_io(struct bio *bio, int err)
+static void raid_write_end_io(struct bio *bio)
{
struct btrfs_raid_bio *rbio = bio->bi_private;
+ int err = bio->bi_error;
if (err)
fail_bio_stripe(rbio, bio);
@@ -893,7 +893,7 @@
if (atomic_read(&rbio->error) > rbio->bbio->max_errors)
err = -EIO;
- rbio_orig_end_io(rbio, err, 0);
+ rbio_orig_end_io(rbio, err);
return;
}
@@ -1071,7 +1071,7 @@
* devices or if they are not contiguous
*/
if (last_end == disk_start && stripe->dev->bdev &&
- test_bit(BIO_UPTODATE, &last->bi_flags) &&
+ !last->bi_error &&
last->bi_bdev == stripe->dev->bdev) {
ret = bio_add_page(last, page, PAGE_CACHE_SIZE, 0);
if (ret == PAGE_CACHE_SIZE)
@@ -1087,7 +1087,6 @@
bio->bi_iter.bi_size = 0;
bio->bi_bdev = stripe->dev->bdev;
bio->bi_iter.bi_sector = disk_start >> 9;
- set_bit(BIO_UPTODATE, &bio->bi_flags);
bio_add_page(bio, page, PAGE_CACHE_SIZE, 0);
bio_list_add(bio_list, bio);
@@ -1312,13 +1311,12 @@
bio->bi_private = rbio;
bio->bi_end_io = raid_write_end_io;
- BUG_ON(!test_bit(BIO_UPTODATE, &bio->bi_flags));
submit_bio(WRITE, bio);
}
return;
cleanup:
- rbio_orig_end_io(rbio, -EIO, 0);
+ rbio_orig_end_io(rbio, -EIO);
}
/*
@@ -1441,11 +1439,11 @@
* This will usually kick off finish_rmw once all the bios are read in, but it
* may trigger parity reconstruction if we had any errors along the way
*/
-static void raid_rmw_end_io(struct bio *bio, int err)
+static void raid_rmw_end_io(struct bio *bio)
{
struct btrfs_raid_bio *rbio = bio->bi_private;
- if (err)
+ if (bio->bi_error)
fail_bio_stripe(rbio, bio);
else
set_bio_pages_uptodate(bio);
@@ -1455,7 +1453,6 @@
if (!atomic_dec_and_test(&rbio->stripes_pending))
return;
- err = 0;
if (atomic_read(&rbio->error) > rbio->bbio->max_errors)
goto cleanup;
@@ -1469,7 +1466,7 @@
cleanup:
- rbio_orig_end_io(rbio, -EIO, 0);
+ rbio_orig_end_io(rbio, -EIO);
}
static void async_rmw_stripe(struct btrfs_raid_bio *rbio)
@@ -1572,14 +1569,13 @@
btrfs_bio_wq_end_io(rbio->fs_info, bio,
BTRFS_WQ_ENDIO_RAID56);
- BUG_ON(!test_bit(BIO_UPTODATE, &bio->bi_flags));
submit_bio(READ, bio);
}
/* the actual write will happen once the reads are done */
return 0;
cleanup:
- rbio_orig_end_io(rbio, -EIO, 0);
+ rbio_orig_end_io(rbio, -EIO);
return -EIO;
finish:
@@ -1964,7 +1960,7 @@
else
clear_bit(RBIO_CACHE_READY_BIT, &rbio->flags);
- rbio_orig_end_io(rbio, err, err == 0);
+ rbio_orig_end_io(rbio, err);
} else if (err == 0) {
rbio->faila = -1;
rbio->failb = -1;
@@ -1976,7 +1972,7 @@
else
BUG();
} else {
- rbio_orig_end_io(rbio, err, 0);
+ rbio_orig_end_io(rbio, err);
}
}
@@ -1984,7 +1980,7 @@
* This is called only for stripes we've read from disk to
* reconstruct the parity.
*/
-static void raid_recover_end_io(struct bio *bio, int err)
+static void raid_recover_end_io(struct bio *bio)
{
struct btrfs_raid_bio *rbio = bio->bi_private;
@@ -1992,7 +1988,7 @@
* we only read stripe pages off the disk, set them
* up to date if there were no errors
*/
- if (err)
+ if (bio->bi_error)
fail_bio_stripe(rbio, bio);
else
set_bio_pages_uptodate(bio);
@@ -2002,7 +1998,7 @@
return;
if (atomic_read(&rbio->error) > rbio->bbio->max_errors)
- rbio_orig_end_io(rbio, -EIO, 0);
+ rbio_orig_end_io(rbio, -EIO);
else
__raid_recover_end_io(rbio);
}
@@ -2094,7 +2090,6 @@
btrfs_bio_wq_end_io(rbio->fs_info, bio,
BTRFS_WQ_ENDIO_RAID56);
- BUG_ON(!test_bit(BIO_UPTODATE, &bio->bi_flags));
submit_bio(READ, bio);
}
out:
@@ -2102,7 +2097,7 @@
cleanup:
if (rbio->operation == BTRFS_RBIO_READ_REBUILD)
- rbio_orig_end_io(rbio, -EIO, 0);
+ rbio_orig_end_io(rbio, -EIO);
return -EIO;
}
@@ -2277,11 +2272,12 @@
* end io function used by finish_rmw. When we finally
* get here, we've written a full stripe
*/
-static void raid_write_parity_end_io(struct bio *bio, int err)
+static void raid_write_parity_end_io(struct bio *bio)
{
struct btrfs_raid_bio *rbio = bio->bi_private;
+ int err = bio->bi_error;
- if (err)
+ if (bio->bi_error)
fail_bio_stripe(rbio, bio);
bio_put(bio);
@@ -2294,7 +2290,7 @@
if (atomic_read(&rbio->error))
err = -EIO;
- rbio_orig_end_io(rbio, err, 0);
+ rbio_orig_end_io(rbio, err);
}
static noinline void finish_parity_scrub(struct btrfs_raid_bio *rbio,
@@ -2437,7 +2433,7 @@
nr_data = bio_list_size(&bio_list);
if (!nr_data) {
/* Every parity is right */
- rbio_orig_end_io(rbio, 0, 0);
+ rbio_orig_end_io(rbio, 0);
return;
}
@@ -2450,13 +2446,12 @@
bio->bi_private = rbio;
bio->bi_end_io = raid_write_parity_end_io;
- BUG_ON(!test_bit(BIO_UPTODATE, &bio->bi_flags));
submit_bio(WRITE, bio);
}
return;
cleanup:
- rbio_orig_end_io(rbio, -EIO, 0);
+ rbio_orig_end_io(rbio, -EIO);
}
static inline int is_data_stripe(struct btrfs_raid_bio *rbio, int stripe)
@@ -2524,7 +2519,7 @@
return;
cleanup:
- rbio_orig_end_io(rbio, -EIO, 0);
+ rbio_orig_end_io(rbio, -EIO);
}
/*
@@ -2535,11 +2530,11 @@
* This will usually kick off finish_rmw once all the bios are read in, but it
* may trigger parity reconstruction if we had any errors along the way
*/
-static void raid56_parity_scrub_end_io(struct bio *bio, int err)
+static void raid56_parity_scrub_end_io(struct bio *bio)
{
struct btrfs_raid_bio *rbio = bio->bi_private;
- if (err)
+ if (bio->bi_error)
fail_bio_stripe(rbio, bio);
else
set_bio_pages_uptodate(bio);
@@ -2632,14 +2627,13 @@
btrfs_bio_wq_end_io(rbio->fs_info, bio,
BTRFS_WQ_ENDIO_RAID56);
- BUG_ON(!test_bit(BIO_UPTODATE, &bio->bi_flags));
submit_bio(READ, bio);
}
/* the actual write will happen once the reads are done */
return;
cleanup:
- rbio_orig_end_io(rbio, -EIO, 0);
+ rbio_orig_end_io(rbio, -EIO);
return;
finish: