From: Filipe Manana <fdmanana@xxxxxxxx>
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.
Cc: stable@xxxxxxxxxxxxxxx # 4.3+
Fixes: 4246a0b63bd8 ("block: add a bi_error field to struct bio")
Signed-off-by: Filipe Manana <fdmanana@xxxxxxxx>
---
V2: Updated commit message to reflect affected kernel versions.
fs/btrfs/inode.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 600bf0d..e0ad8b2 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -7985,6 +7985,7 @@ 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)
@@ -8039,6 +8040,7 @@ static void btrfs_endio_direct_write(struct bio *bio)
kfree(dip);
+ dio_bio->bi_error = bio->bi_error;
dio_end_io(dio_bio, bio->bi_error);
bio_put(bio);
}
--
2.7.0.rc3
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