| From | Greg Kroah-Hartman <> | Subject | [PATCH 4.4 028/137] Btrfs: fix direct IO requests not reporting IO error to user space | Date | Tue, 23 Feb 2016 19:32:39 -0800 |
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4.4-stable review patch. If anyone has any objections, please let me know.
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From: Filipe Manana <fdmanana@suse.com>
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: 4246a0b63bd8 ("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>
--- fs/btrfs/inode.c | 2 ++ 1 file changed, 2 insertions(+)
--- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -7997,6 +7997,7 @@ static void btrfs_endio_direct_read(stru 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); }
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