diff options
author | Qu Wenruo <wqu@suse.com> | 2020-07-13 04:03:22 +0300 |
---|---|---|
committer | David Sterba <dsterba@suse.com> | 2020-07-27 13:55:45 +0300 |
commit | fd7fb634d69a7d8c91aa3166b77351b96954aae4 (patch) | |
tree | e6dc66d37a98573aa2733e94cd7f79e887a612df /fs | |
parent | 44d354abf33e92a5e73b965c84caf5a5d5e58a0b (diff) | |
download | linux-fd7fb634d69a7d8c91aa3166b77351b96954aae4.tar.xz |
btrfs: add comments for btrfs_reserve_flush_enum
This enum is the interface exposed to developers.
Although we have a detailed comment explaining the whole idea of space
flushing at the beginning of space-info.c, the exposed enum interface
doesn't have any comment.
Some corner cases, like BTRFS_RESERVE_FLUSH_ALL and
BTRFS_RESERVE_FLUSH_ALL_STEAL can be interrupted by fatal signals, are
not explained at all.
So add some simple comments for these enums as a quick reference.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Diffstat (limited to 'fs')
-rw-r--r-- | fs/btrfs/ctree.h | 34 |
1 files changed, 32 insertions, 2 deletions
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h index 050760dfc56d..b70c2024296f 100644 --- a/fs/btrfs/ctree.h +++ b/fs/btrfs/ctree.h @@ -2560,16 +2560,46 @@ int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans, int btrfs_extent_readonly(struct btrfs_fs_info *fs_info, u64 bytenr); void btrfs_clear_space_info_full(struct btrfs_fs_info *info); +/* + * Different levels for to flush space when doing space reservations. + * + * The higher the level, the more methods we try to reclaim space. + */ enum btrfs_reserve_flush_enum { /* If we are in the transaction, we can't flush anything.*/ BTRFS_RESERVE_NO_FLUSH, + /* - * Flushing delalloc may cause deadlock somewhere, in this - * case, use FLUSH LIMIT + * Flush space by: + * - Running delayed inode items + * - Allocating a new chunk */ BTRFS_RESERVE_FLUSH_LIMIT, + + /* + * Flush space by: + * - Running delayed inode items + * - Running delayed refs + * - Running delalloc and waiting for ordered extents + * - Allocating a new chunk + */ BTRFS_RESERVE_FLUSH_EVICT, + + /* + * Flush space by above mentioned methods and by: + * - Running delayed iputs + * - Commiting transaction + * + * Can be interruped by fatal signal. + */ BTRFS_RESERVE_FLUSH_ALL, + + /* + * Pretty much the same as FLUSH_ALL, but can also steal space from + * global rsv. + * + * Can be interruped by fatal signal. + */ BTRFS_RESERVE_FLUSH_ALL_STEAL, }; |