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    Subject[ 065/108] md/raid1: close some possible races on write errors during resync
    3.2-stable review patch.  If anyone has any objections, please let me know.


    From: NeilBrown <>

    commit 58e94ae18478c08229626daece2fc108a4a23261 upstream.

    commit 4367af556133723d0f443e14ca8170d9447317cb
    md/raid1: clear bad-block record when write succeeds.

    Added a 'reschedule_retry' call possibility at the end of
    end_sync_write, but didn't add matching code at the end of
    sync_request_write. So if the writes complete very quickly, or
    scheduling makes it seem that way, then we can miss rescheduling
    the request and the resync could hang.

    Also commit 73d5c38a9536142e062c35997b044e89166e063b
    md: avoid races when stopping resync.

    Fix a race condition in this same code in end_sync_write but didn't
    make the change in sync_request_write.

    This patch updates sync_request_write to fix both of those.
    Patch is suitable for 3.1 and later kernels.

    Reported-by: Alexander Lyakas <>
    Original-version-by: Alexander Lyakas <>
    Signed-off-by: NeilBrown <>
    Signed-off-by: Ben Hutchings <>
    drivers/md/raid1.c | 10 ++++++++--
    1 file changed, 8 insertions(+), 2 deletions(-)

    diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
    index 240ff31..cacd008 100644
    --- a/drivers/md/raid1.c
    +++ b/drivers/md/raid1.c
    @@ -1818,8 +1818,14 @@ static void sync_request_write(struct mddev *mddev, struct r1bio *r1_bio)

    if (atomic_dec_and_test(&r1_bio->remaining)) {
    /* if we're here, all write(s) have completed, so clean up */
    - md_done_sync(mddev, r1_bio->sectors, 1);
    - put_buf(r1_bio);
    + int s = r1_bio->sectors;
    + if (test_bit(R1BIO_MadeGood, &r1_bio->state) ||
    + test_bit(R1BIO_WriteError, &r1_bio->state))
    + reschedule_retry(r1_bio);
    + else {
    + put_buf(r1_bio);
    + md_done_sync(mddev, s, 1);
    + }

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      Last update: 2012-07-23 04:41    [W:0.023 / U:88.092 seconds]
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