[PATCH 5.17 046/772] btrfs: zoned: properly finish block group on metadata write

Greg Kroah-Hartman
2022-06-07T20:21:58Z

From: Naohiro Aota <naohiro.aota@wdc.com>

commit 56fbb0a4e8b3e929e41cc846e6ef89eb01152201 upstream.

Commit be1a1d7a5d24 ("btrfs: zoned: finish fully written block group")
introduced zone finishing code both for data and metadata end_io path.
However, the metadata side is not working as it should. First, it
compares logical address (eb->start + eb->len) with offset within a
block group (cache->zone_capacity) in submit_eb_page(). That essentially
disabled zone finishing on metadata end_io path.

Furthermore, fixing the issue above revealed we cannot call
btrfs_zone_finish_endio() in end_extent_buffer_writeback(). We cannot
call btrfs_lookup_block_group() which require spin lock inside end_io
context.

Introduce btrfs_schedule_zone_finish_bg() to wait for the extent buffer
writeback and do the zone finish IO in a workqueue.

Also, drop EXTENT_BUFFER_ZONE_FINISH as it is no longer used.

Fixes: be1a1d7a5d24 ("btrfs: zoned: finish fully written block group")
CC: stable@vger.kernel.org # 5.16+
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
fs/btrfs/block-group.h | 2 ++
fs/btrfs/extent_io.c | 6 +-----
fs/btrfs/extent_io.h | 1 -
fs/btrfs/zoned.c | 31 +++++++++++++++++++++++++++++++
fs/btrfs/zoned.h | 5 +++++
5 files changed, 39 insertions(+), 6 deletions(-)

--- a/fs/btrfs/block-group.h
+++ b/fs/btrfs/block-group.h
@@ -211,6 +211,8 @@ struct btrfs_block_group {
u64 meta_write_pointer;
struct map_lookup *physical_map;
struct list_head active_bg_list;
+ struct work_struct zone_finish_work;
+ struct extent_buffer *last_eb;
};

static inline u64 btrfs_block_group_end(struct btrfs_block_group *block_group)
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -4173,9 +4173,6 @@ void wait_on_extent_buffer_writeback(str

static void end_extent_buffer_writeback(struct extent_buffer *eb)
{
- if (test_bit(EXTENT_BUFFER_ZONE_FINISH, &eb->bflags))
- btrfs_zone_finish_endio(eb->fs_info, eb->start, eb->len);
-
clear_bit(EXTENT_BUFFER_WRITEBACK, &eb->bflags);
smp_mb__after_atomic();
wake_up_bit(&eb->bflags, EXTENT_BUFFER_WRITEBACK);
@@ -4795,8 +4792,7 @@ static int submit_eb_page(struct page *p
/*
* Implies write in zoned mode. Mark the last eb in a block group.
*/
- if (cache->seq_zone && eb->start + eb->len == cache->zone_capacity)
- set_bit(EXTENT_BUFFER_ZONE_FINISH, &eb->bflags);
+ btrfs_schedule_zone_finish_bg(cache, eb);
btrfs_put_block_group(cache);
}
ret = write_one_eb(eb, wbc, epd);
--- a/fs/btrfs/extent_io.h
+++ b/fs/btrfs/extent_io.h
@@ -32,7 +32,6 @@ enum {
/* write IO error */
EXTENT_BUFFER_WRITE_ERR,
EXTENT_BUFFER_NO_CHECK,
- EXTENT_BUFFER_ZONE_FINISH,
};

/* these are flags for __process_pages_contig */
--- a/fs/btrfs/zoned.c
+++ b/fs/btrfs/zoned.c
@@ -2007,6 +2007,37 @@ out:
btrfs_put_block_group(block_group);
}

+static void btrfs_zone_finish_endio_workfn(struct work_struct *work)
+{
+ struct btrfs_block_group *bg =
+ container_of(work, struct btrfs_block_group, zone_finish_work);
+
+ wait_on_extent_buffer_writeback(bg->last_eb);
+ free_extent_buffer(bg->last_eb);
+ btrfs_zone_finish_endio(bg->fs_info, bg->start, bg->length);
+ btrfs_put_block_group(bg);
+}
+
+void btrfs_schedule_zone_finish_bg(struct btrfs_block_group *bg,
+ struct extent_buffer *eb)
+{
+ if (!bg->seq_zone || eb->start + eb->len * 2 <= bg->start + bg->zone_capacity)
+ return;
+
+ if (WARN_ON(bg->zone_finish_work.func == btrfs_zone_finish_endio_workfn)) {
+ btrfs_err(bg->fs_info, "double scheduling of bg %llu zone finishing",
+ bg->start);
+ return;
+ }
+
+ /* For the work */
+ btrfs_get_block_group(bg);
+ atomic_inc(&eb->refs);
+ bg->last_eb = eb;
+ INIT_WORK(&bg->zone_finish_work, btrfs_zone_finish_endio_workfn);
+ queue_work(system_unbound_wq, &bg->zone_finish_work);
+}
+
void btrfs_clear_data_reloc_bg(struct btrfs_block_group *bg)
{
struct btrfs_fs_info *fs_info = bg->fs_info;
--- a/fs/btrfs/zoned.h
+++ b/fs/btrfs/zoned.h
@@ -76,6 +76,8 @@ int btrfs_zone_finish(struct btrfs_block
bool btrfs_can_activate_zone(struct btrfs_fs_devices *fs_devices, u64 flags);
void btrfs_zone_finish_endio(struct btrfs_fs_info *fs_info, u64 logical,
u64 length);
+void btrfs_schedule_zone_finish_bg(struct btrfs_block_group *bg,
+ struct extent_buffer *eb);
void btrfs_clear_data_reloc_bg(struct btrfs_block_group *bg);
void btrfs_free_zone_cache(struct btrfs_fs_info *fs_info);
#else /* CONFIG_BLK_DEV_ZONED */
@@ -233,6 +235,9 @@ static inline bool btrfs_can_activate_zo
static inline void btrfs_zone_finish_endio(struct btrfs_fs_info *fs_info,
u64 logical, u64 length) { }

+static inline void btrfs_schedule_zone_finish_bg(struct btrfs_block_group *bg,
+ struct extent_buffer *eb) { }
+
static inline void btrfs_clear_data_reloc_bg(struct btrfs_block_group *bg) { }

static inline void btrfs_free_zone_cache(struct btrfs_fs_info *fs_info) { }