| Message ID | bd9358f329b4574724250f1c0ba1ef2939f1feaa.1693293259.git.wqu@suse.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | btrfs: do not require EXTENT_NOWAIT for btrfs_redirty_list_add() | expand |
On Tue, Aug 29, 2023 at 03:14:25PM +0800, Qu Wenruo wrote: > The flag EXTENT_NOWAIT is a special flag to notify extent-io-tree code > that this operation should not sleep for the extent state preallocation. > > However for btrfs_redirty_list_add(), all callers are able to sleep: > > - clean_log_buffer() > Just 2 lines before, we call btrfs_pin_reserved_extent(), which calls > pin_down_extent(), and that function does not require EXTENT_NOWAIT. > Thus we're safe to call it without EXTENT_NOWAIT. > > - btrfs_free_tree_block() > This function have several call sites which trigger tree read, e.g. > walk_up_proc(), thus we're safe to call it without EXTENT_NOWAIT. > > Thus there is no need to require EXTENT_NOWAIT flag. > > Signed-off-by: Qu Wenruo <wqu@suse.com> Added to misc-next, thanks. I did some research if we need the EXTENT_NOWAIT at all, it's obscured by a lot of code refactoring but it's still needed due to add_extent_mapping extent_map_device_set_bits done under extent_map_tree::lock (rwlock_t), added in 1c11b63eff2a ("btrfs: replace pending/pinned chunks lists with io tree").
diff --git a/fs/btrfs/zoned.c b/fs/btrfs/zoned.c index 21aad9704026..d42a672539a5 100644 --- a/fs/btrfs/zoned.c +++ b/fs/btrfs/zoned.c @@ -1609,7 +1609,7 @@ void btrfs_redirty_list_add(struct btrfs_transaction *trans, set_bit(EXTENT_BUFFER_NO_CHECK, &eb->bflags); set_extent_buffer_dirty(eb); set_extent_bit(&trans->dirty_pages, eb->start, eb->start + eb->len - 1, - EXTENT_DIRTY | EXTENT_NOWAIT, NULL); + EXTENT_DIRTY, NULL); } bool btrfs_use_zone_append(struct btrfs_bio *bbio)
The flag EXTENT_NOWAIT is a special flag to notify extent-io-tree code that this operation should not sleep for the extent state preallocation. However for btrfs_redirty_list_add(), all callers are able to sleep: - clean_log_buffer() Just 2 lines before, we call btrfs_pin_reserved_extent(), which calls pin_down_extent(), and that function does not require EXTENT_NOWAIT. Thus we're safe to call it without EXTENT_NOWAIT. - btrfs_free_tree_block() This function have several call sites which trigger tree read, e.g. walk_up_proc(), thus we're safe to call it without EXTENT_NOWAIT. Thus there is no need to require EXTENT_NOWAIT flag. Signed-off-by: Qu Wenruo <wqu@suse.com> --- fs/btrfs/zoned.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)