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Btrfs: Fix the multi-bio code to save the original bio for completion

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The multi-bio code is responsible for duplicating blocks in raid1 and
single spindle duplication.  It has counters to make sure all of
the locations for a given extent are properly written before io completion
is returned to the higher layers.

But, it didn't always complete the same bio it was given, sometimes a
clone was completed instead.  This lead to problems with the async
work queues because they saved a pointer to the bio in a struct off
bi_private.

The fix is to remember the original bio and only complete that one.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
This commit is contained in:
Chris Mason 2008-08-05 10:13:57 -04:00
parent ae01a0abf3
commit 7d2b4daa67
2 changed files with 11 additions and 1 deletions
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11
fs/btrfs/volumes.c
View file

@ -2070,6 +2070,7 @@ static int end_bio_multi_stripe(struct bio *bio,
#endif
{
struct btrfs_multi_bio *multi = bio->bi_private;
int is_orig_bio = 0;
#if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,23)
if (bio->bi_size)
@ -2078,7 +2079,14 @@ static int end_bio_multi_stripe(struct bio *bio,
if (err)
atomic_inc(&multi->error);
if (bio == multi->orig_bio)
is_orig_bio = 1;
if (atomic_dec_and_test(&multi->stripes_pending)) {
if (!is_orig_bio) {
bio_put(bio);
bio = multi->orig_bio;
}
bio->bi_private = multi->private;
bio->bi_end_io = multi->end_io;
/* only send an error to the higher layers if it is
@ -2101,7 +2109,7 @@ static int end_bio_multi_stripe(struct bio *bio,
#else
bio_endio(bio, err);
#endif
} else {
} else if (!is_orig_bio) {
bio_put(bio);
}
#if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,23)
@ -2196,6 +2204,7 @@ int btrfs_map_bio(struct btrfs_root *root, int rw, struct bio *bio,
}
multi->end_io = first_bio->bi_end_io;
multi->private = first_bio->bi_private;
multi->orig_bio = first_bio;
atomic_set(&multi->stripes_pending, multi->num_stripes);
while(dev_nr < total_devs) {

1
fs/btrfs/volumes.h
View file

@ -95,6 +95,7 @@ struct btrfs_bio_stripe {
struct btrfs_multi_bio {
atomic_t stripes_pending;
bio_end_io_t *end_io;
struct bio *orig_bio;
void *private;
atomic_t error;
int max_errors;