6.1-stable review patch. If anyone has any objections, please let me know.
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From: Naohiro Aota naohiro.aota@wdc.com
commit 8cd44dd1d17a23d5cc8c443c659ca57aa76e2fa5 upstream.
When btrfs makes a block group read-only, it adds all free regions in the block group to space_info->bytes_readonly. That free space excludes reserved and pinned regions. OTOH, when btrfs makes the block group read-write again, it moves all the unused regions into the block group's zone_unusable. That unused region includes reserved and pinned regions. As a result, it counts too much zone_unusable bytes.
Fortunately (or unfortunately), having erroneous zone_unusable does not affect the calculation of space_info->bytes_readonly, because free space (num_bytes in btrfs_dec_block_group_ro) calculation is done based on the erroneous zone_unusable and it reduces the num_bytes just to cancel the error.
This behavior can be easily discovered by adding a WARN_ON to check e.g, "bg->pinned > 0" in btrfs_dec_block_group_ro(), and running fstests test case like btrfs/282.
Fix it by properly considering pinned and reserved in btrfs_dec_block_group_ro(). Also, add a WARN_ON and introduce btrfs_space_info_update_bytes_zone_unusable() to catch a similar mistake.
Fixes: 169e0da91a21 ("btrfs: zoned: track unusable bytes for zones") CC: stable@vger.kernel.org # 5.15+ Signed-off-by: Naohiro Aota naohiro.aota@wdc.com Reviewed-by: Josef Bacik josef@toxicpanda.com Reviewed-by: Johannes Thumshirn johannes.thumshirn@wdc.com Signed-off-by: David Sterba dsterba@suse.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- fs/btrfs/block-group.c | 13 ++++++++----- fs/btrfs/extent-tree.c | 3 ++- fs/btrfs/free-space-cache.c | 4 +++- fs/btrfs/space-info.c | 2 +- fs/btrfs/space-info.h | 1 + include/trace/events/btrfs.h | 8 ++++++++ 6 files changed, 23 insertions(+), 8 deletions(-)
--- a/fs/btrfs/block-group.c +++ b/fs/btrfs/block-group.c @@ -1065,8 +1065,8 @@ int btrfs_remove_block_group(struct btrf block_group->space_info->active_total_bytes -= block_group->length; block_group->space_info->bytes_readonly -= (block_group->length - block_group->zone_unusable); - block_group->space_info->bytes_zone_unusable -= - block_group->zone_unusable; + btrfs_space_info_update_bytes_zone_unusable(fs_info, block_group->space_info, + -block_group->zone_unusable); block_group->space_info->disk_total -= block_group->length * factor;
spin_unlock(&block_group->space_info->lock); @@ -1250,7 +1250,8 @@ static int inc_block_group_ro(struct btr if (btrfs_is_zoned(cache->fs_info)) { /* Migrate zone_unusable bytes to readonly */ sinfo->bytes_readonly += cache->zone_unusable; - sinfo->bytes_zone_unusable -= cache->zone_unusable; + btrfs_space_info_update_bytes_zone_unusable(cache->fs_info, sinfo, + -cache->zone_unusable); cache->zone_unusable = 0; } cache->ro++; @@ -2812,9 +2813,11 @@ void btrfs_dec_block_group_ro(struct btr if (btrfs_is_zoned(cache->fs_info)) { /* Migrate zone_unusable bytes back */ cache->zone_unusable = - (cache->alloc_offset - cache->used) + + (cache->alloc_offset - cache->used - cache->pinned - + cache->reserved) + (cache->length - cache->zone_capacity); - sinfo->bytes_zone_unusable += cache->zone_unusable; + btrfs_space_info_update_bytes_zone_unusable(cache->fs_info, sinfo, + cache->zone_unusable); sinfo->bytes_readonly -= cache->zone_unusable; } num_bytes = cache->length - cache->reserved - --- a/fs/btrfs/extent-tree.c +++ b/fs/btrfs/extent-tree.c @@ -2731,7 +2731,8 @@ static int unpin_extent_range(struct btr readonly = true; } else if (btrfs_is_zoned(fs_info)) { /* Need reset before reusing in a zoned block group */ - space_info->bytes_zone_unusable += len; + btrfs_space_info_update_bytes_zone_unusable(fs_info, space_info, + len); readonly = true; } spin_unlock(&cache->lock); --- a/fs/btrfs/free-space-cache.c +++ b/fs/btrfs/free-space-cache.c @@ -2702,8 +2702,10 @@ static int __btrfs_add_free_space_zoned( * If the block group is read-only, we should account freed space into * bytes_readonly. */ - if (!block_group->ro) + if (!block_group->ro) { block_group->zone_unusable += to_unusable; + WARN_ON(block_group->zone_unusable > block_group->length); + } spin_unlock(&ctl->tree_lock); if (!used) { spin_lock(&block_group->lock); --- a/fs/btrfs/space-info.c +++ b/fs/btrfs/space-info.c @@ -311,7 +311,7 @@ void btrfs_add_bg_to_space_info(struct b found->bytes_used += block_group->used; found->disk_used += block_group->used * factor; found->bytes_readonly += block_group->bytes_super; - found->bytes_zone_unusable += block_group->zone_unusable; + btrfs_space_info_update_bytes_zone_unusable(info, found, block_group->zone_unusable); if (block_group->length > 0) found->full = 0; btrfs_try_granting_tickets(info, found); --- a/fs/btrfs/space-info.h +++ b/fs/btrfs/space-info.h @@ -121,6 +121,7 @@ btrfs_space_info_update_##name(struct bt
DECLARE_SPACE_INFO_UPDATE(bytes_may_use, "space_info"); DECLARE_SPACE_INFO_UPDATE(bytes_pinned, "pinned"); +DECLARE_SPACE_INFO_UPDATE(bytes_zone_unusable, "zone_unusable");
int btrfs_init_space_info(struct btrfs_fs_info *fs_info); void btrfs_add_bg_to_space_info(struct btrfs_fs_info *info, --- a/include/trace/events/btrfs.h +++ b/include/trace/events/btrfs.h @@ -2322,6 +2322,14 @@ DEFINE_EVENT(btrfs__space_info_update, u TP_ARGS(fs_info, sinfo, old, diff) );
+DEFINE_EVENT(btrfs__space_info_update, update_bytes_zone_unusable, + + TP_PROTO(const struct btrfs_fs_info *fs_info, + const struct btrfs_space_info *sinfo, u64 old, s64 diff), + + TP_ARGS(fs_info, sinfo, old, diff) +); + DECLARE_EVENT_CLASS(btrfs_raid56_bio,
TP_PROTO(const struct btrfs_raid_bio *rbio,