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Btrfs: fix direct IO requests not reporting IO error to user space

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commit 1636d1d77ef4e01e57f706a4cae3371463896136 upstream.

If a bio for a direct IO request fails, we were not setting the error in
the parent bio (the main DIO bio), making us not return the error to
user space in btrfs_direct_IO(), that is, it made __blockdev_direct_IO()
return the number of bytes issued for IO and not the error a bio created
and submitted by btrfs_submit_direct() got from the block layer.
This essentially happens because when we call:

   dio_end_io(dio_bio, bio->bi_error);

It does not set dio_bio->bi_error to the value of the second argument.
So just add this missing assignment in endio callbacks, just as we do in
the error path at btrfs_submit_direct() when we fail to clone the dio bio
or allocate its private object. This follows the convention of what is
done with other similar APIs such as bio_endio() where the caller is
responsible for setting the bi_error field in the bio it passes as an
argument to bio_endio().

This was detected by the new generic test cases in xfstests: 271, 272,
276 and 278. Which essentially setup a dm error target, then load the
error table, do a direct IO write and unload the error table. They
expect the write to fail with -EIO, which was not getting reported
when testing against btrfs.

Fixes: 4246a0b63b ("block: add a bi_error field to struct bio")
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Filipe Manana 2016-02-15 16:20:26 +00:00 • committed by Greg Kroah-Hartman
parent e8eced78e0
commit ba6d92801b
1 changed files with 2 additions and 0 deletions
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2
fs/btrfs/inode.c
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@ -7997,6 +7997,7 @@ static void btrfs_endio_direct_read(struct bio *bio)
kfree(dip);
dio_bio->bi_error = bio->bi_error;
dio_end_io(dio_bio, bio->bi_error);
if (io_bio->end_io)
@ -8042,6 +8043,7 @@ out_test:
kfree(dip);
dio_bio->bi_error = bio->bi_error;
dio_end_io(dio_bio, bio->bi_error);
bio_put(bio);
}