diff options
| -rw-r--r-- | fs/btrfs/space-info.c | 32 |
1 files changed, 32 insertions, 0 deletions
diff --git a/fs/btrfs/space-info.c b/fs/btrfs/space-info.c index 45114df89de1..571bb13587d5 100644 --- a/fs/btrfs/space-info.c +++ b/fs/btrfs/space-info.c @@ -345,8 +345,10 @@ static u64 calc_available_free_space(struct btrfs_fs_info *fs_info, struct btrfs_space_info *space_info, enum btrfs_reserve_flush_enum flush) { + struct btrfs_space_info *data_sinfo; u64 profile; u64 avail; + u64 data_chunk_size; int factor; if (space_info->flags & BTRFS_BLOCK_GROUP_SYSTEM) @@ -364,6 +366,36 @@ static u64 calc_available_free_space(struct btrfs_fs_info *fs_info, */ factor = btrfs_bg_type_to_factor(profile); avail = div_u64(avail, factor); + if (avail == 0) + return 0; + + /* + * Calculate the data_chunk_size, space_info->chunk_size is the + * "optimal" chunk size based on the fs size. However when we actually + * allocate the chunk we will strip this down further, making it no more + * than 10% of the disk or 1G, whichever is smaller. + */ + data_sinfo = btrfs_find_space_info(fs_info, BTRFS_BLOCK_GROUP_DATA); + data_chunk_size = min(data_sinfo->chunk_size, + mult_perc(fs_info->fs_devices->total_rw_bytes, 10)); + data_chunk_size = min_t(u64, data_chunk_size, SZ_1G); + + /* + * Since data allocations immediately use block groups as part of the + * reservation, because we assume that data reservations will == actual + * usage, we could potentially overcommit and then immediately have that + * available space used by a data allocation, which could put us in a + * bind when we get close to filling the file system. + * + * To handle this simply remove the data_chunk_size from the available + * space. If we are relatively empty this won't affect our ability to + * overcommit much, and if we're very close to full it'll keep us from + * getting into a position where we've given ourselves very little + * metadata wiggle room. + */ + if (avail <= data_chunk_size) + return 0; + avail -= data_chunk_size; /* * If we aren't flushing all things, let us overcommit up to |