Currently how btrfs dio deals with split dio write is not good enough if dio write is split into several segments due to the lack of contiguous space, a large dio write like 'dd bs=1G count=1' can end up with incorrect outstanding_extents counter and endio would complain loudly with an assertion.
This fixes the problem by compensating the outstanding_extents counter in inode if a large dio write gets split. Reported-by: Anand Jain <[email protected]> Signed-off-by: Liu Bo <[email protected]> --- fs/btrfs/inode.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index a4c8796..4175987 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -7641,11 +7641,18 @@ static void adjust_dio_outstanding_extents(struct inode *inode, * within our reservation, otherwise we need to adjust our inode * counter appropriately. */ - if (dio_data->outstanding_extents) { + if (dio_data->outstanding_extents >= num_extents) { dio_data->outstanding_extents -= num_extents; } else { + /* + * If dio write length has been split due to no large enough + * contiguous space, we need to compensate our inode counter + * appropriately. + */ + u64 num_needed = num_extents - dio_data->outstanding_extents; + spin_lock(&BTRFS_I(inode)->lock); - BTRFS_I(inode)->outstanding_extents += num_extents; + BTRFS_I(inode)->outstanding_extents += num_needed; spin_unlock(&BTRFS_I(inode)->lock); } } -- 2.5.5 -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
