Commit cf1167d5 authored by Liu Bo's avatar Liu Bo Committed by David Sterba

Btrfs: fix kernel oops while reading compressed data

The kernel oops happens at

kernel BUG at fs/btrfs/extent_io.c:2104!
...
RIP: clean_io_failure+0x263/0x2a0 [btrfs]

It's showing that read-repair code is using an improper mirror index.
This is due to the fact that compression read's endio hasn't recorded
the failed mirror index in %cb->orig_bio.

With this, btrfs's read-repair can work properly on reading compressed
data.
Signed-off-by: default avatarLiu Bo <bo.li.liu@oracle.com>
Reported-by: default avatarPaul Jones <paul@pauljones.id.au>
Tested-by: default avatarPaul Jones <paul@pauljones.id.au>
Reviewed-by: default avatarDavid Sterba <dsterba@suse.com>
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent bd7d63c2
...@@ -107,6 +107,7 @@ static void end_compressed_bio_read(struct bio *bio) ...@@ -107,6 +107,7 @@ static void end_compressed_bio_read(struct bio *bio)
struct inode *inode; struct inode *inode;
struct page *page; struct page *page;
unsigned long index; unsigned long index;
unsigned int mirror = btrfs_io_bio(bio)->mirror_num;
int ret; int ret;
if (bio->bi_status) if (bio->bi_status)
...@@ -118,6 +119,14 @@ static void end_compressed_bio_read(struct bio *bio) ...@@ -118,6 +119,14 @@ static void end_compressed_bio_read(struct bio *bio)
if (!refcount_dec_and_test(&cb->pending_bios)) if (!refcount_dec_and_test(&cb->pending_bios))
goto out; goto out;
/*
* Record the correct mirror_num in cb->orig_bio so that
* read-repair can work properly.
*/
ASSERT(btrfs_io_bio(cb->orig_bio));
btrfs_io_bio(cb->orig_bio)->mirror_num = mirror;
cb->mirror_num = mirror;
inode = cb->inode; inode = cb->inode;
ret = check_compressed_csum(BTRFS_I(inode), cb, ret = check_compressed_csum(BTRFS_I(inode), cb,
(u64)bio->bi_iter.bi_sector << 9); (u64)bio->bi_iter.bi_sector << 9);
......
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