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

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

fs/btrfs/compression.c

+9 −0
Original line number Diff line number Diff line
@@ -107,6 +107,7 @@ static void end_compressed_bio_read(struct bio *bio) 
	struct inode *inode;

	struct page *page;

	unsigned long index;

	unsigned int mirror = btrfs_io_bio(bio)->mirror_num;

	int ret;



	if (bio->bi_status)
@@ -118,6 +119,14 @@ static void end_compressed_bio_read(struct bio *bio) 
	if (!refcount_dec_and_test(&cb->pending_bios))

		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;

	ret = check_compressed_csum(BTRFS_I(inode), cb,

				    (u64)bio->bi_iter.bi_sector << 9);