On 6/21/17 5:15 PM, Chris Mason wrote: > > > On 06/21/2017 05:08 PM, Jeff Mahoney wrote: >> On 6/21/17 4:31 PM, Chris Mason wrote: >>> On 06/21/2017 04:14 PM, Jeff Mahoney wrote: >>>> On 6/14/17 11:44 AM, [email protected] wrote: >>>>> From: Jeff Mahoney <[email protected]> >>>>> >>>>> In a heavy write scenario, we can end up with a large number of pinned >>>>> bytes. This can translate into (very) premature ENOSPC because pinned >>>>> bytes must be accounted for when allowing a reservation but aren't >>>>> accounted for when deciding whether to create a new chunk. >>>>> >>>>> This patch adds the accounting to should_alloc_chunk so that we can >>>>> create the chunk. >>>>> >>>>> Signed-off-by: Jeff Mahoney <[email protected]> >>>>> --- >>>>> fs/btrfs/extent-tree.c | 2 +- >>>>> 1 file changed, 1 insertion(+), 1 deletion(-) >>>>> >>>>> diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c >>>>> index cb0b924..d027807 100644 >>>>> --- a/fs/btrfs/extent-tree.c >>>>> +++ b/fs/btrfs/extent-tree.c >>>>> @@ -4389,7 +4389,7 @@ static int should_alloc_chunk(struct >>>>> btrfs_fs_info *fs_info, >>>>> { >>>>> struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv; >>>>> u64 num_bytes = sinfo->total_bytes - sinfo->bytes_readonly; >>>>> - u64 num_allocated = sinfo->bytes_used + sinfo->bytes_reserved; >>>>> + u64 num_allocated = sinfo->bytes_used + sinfo->bytes_reserved + >>>>> sinfo->bytes_pinned + sinfo->bytes_may_use; >>>>> u64 thresh; >>>>> >>>>> if (force == CHUNK_ALLOC_FORCE) >>>>> >>>> >>>> >>>> Ignore this patch. It certainly allocates chunks more aggressively, >>>> but >>>> it means we end up with a ton of metadata chunks even when we don't >>>> have >>>> much metadata. >>>> >>> >>> Josef and I pushed this needle back and forth a bunch of times in the >>> early days. I still think we can allocate a few more chunks than we do >>> now... >> >> I agree. This patch was to fix an issue that we are seeing during >> installation. It'd stop with ENOSPC with >50GB completely unallocated. >> The patch passed the test cases that were failing before but now it's >> failing differently. I was worried this pattern might be the end result: >> >> Data,single: Size:4.00GiB, Used:3.32GiB >> /dev/vde 4.00GiB >> >> Metadata,DUP: Size:20.00GiB, Used:204.12MiB >> /dev/vde 40.00GiB >> >> System,DUP: Size:8.00MiB, Used:16.00KiB >> /dev/vde 16.00MiB >> >> This is on a fresh file system with just "cp /usr /mnt" executed. >> >> I'm looking into it a bit more now. > > Does this failure still happen with Omar's ENOSPC fix (commit: > 70e7af244f24c94604ef6eca32ad297632018583)
Nope. There aren't any warnings either with or without my patch. Adding Omar's didn't make a difference. -Jeff -- Jeff Mahoney SUSE Labs
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