From: Liu Bo Date: Fri, 23 Dec 2016 01:13:54 +0000 (-0800) Subject: Btrfs: adjust outstanding_extents counter properly when dio write is split X-Git-Tag: C0P2-H0.0--20200415~7930 X-Git-Url: https://git.somdevices.com/?a=commitdiff_plain;h=f76ddff6c5215131483efed20acc896e021abb9f;p=linux.git Btrfs: adjust outstanding_extents counter properly when dio write is split [ Upstream commit c2931667c83ded6504b3857e99cc45b21fa496fb ] 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 Tested-by: Anand Jain Signed-off-by: Liu Bo Signed-off-by: David Sterba Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index a2a014b19f18..8a05fa7e2152 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -7648,11 +7648,18 @@ 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); } }