| Message ID | 20191126162556.150483-5-josef@toxicpanda.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | clean up how we mark block groups read only | expand |
On 2019/11/27 上午12:25, Josef Bacik wrote: > inc_block_group_ro does a calculation to see if we have enough room left > over if we mark this block group as read only in order to see if it's ok > to mark the block group as read only. > > The problem is this calculation _only_ works for data, where our used is > always less than our total. For metadata we will overcommit, so this > will almost always fail for metadata. > > Fix this by exporting btrfs_can_overcommit, and then see if we have > enough space to remove the remaining free space in the block group we > are trying to mark read only. If we do then we can mark this block > group as read only. > > Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: Qu Wenruo <wqu@suse.com> Just as mentioned in patch 3, it would be better to revert b12de52896c0 ("btrfs: scrub: Don't check free space before marking a block group RO") in this patch too. As your new over-commit check also prevent btrfs_inc_block_group_ro() to create empty system chunk, it solves that mentioned bug in a better way. Thanks, Qu > --- > fs/btrfs/block-group.c | 35 ++++++++++++++++++++++++----------- > fs/btrfs/space-info.c | 19 ++++++++++--------- > fs/btrfs/space-info.h | 3 +++ > 3 files changed, 37 insertions(+), 20 deletions(-) > > diff --git a/fs/btrfs/block-group.c b/fs/btrfs/block-group.c > index 5961411500ed..ca55eb6758d1 100644 > --- a/fs/btrfs/block-group.c > +++ b/fs/btrfs/block-group.c > @@ -1184,7 +1184,6 @@ static int inc_block_group_ro(struct btrfs_block_group *cache, int force) > { > struct btrfs_space_info *sinfo = cache->space_info; > u64 num_bytes; > - u64 sinfo_used; > int ret = -ENOSPC; > > spin_lock(&sinfo->lock); > @@ -1205,19 +1204,36 @@ static int inc_block_group_ro(struct btrfs_block_group *cache, int force) > > num_bytes = cache->length - cache->reserved - cache->pinned - > cache->bytes_super - cache->used; > - sinfo_used = btrfs_space_info_used(sinfo, true); > > /* > - * sinfo_used + num_bytes should always <= sinfo->total_bytes. > - * > - * Here we make sure if we mark this bg RO, we still have enough > - * free space as buffer. > + * Data never overcommits, even in mixed mode, so do just the straight > + * check of left over space in how much we have allocated. > */ > - if (sinfo_used + num_bytes <= sinfo->total_bytes) { > + if (sinfo->flags & BTRFS_BLOCK_GROUP_DATA) { > + u64 sinfo_used = btrfs_space_info_used(sinfo, true); > + > + /* > + * Here we make sure if we mark this bg RO, we still have enough > + * free space as buffer. > + */ > + if (sinfo_used + num_bytes <= sinfo->total_bytes) > + ret = 0; > + } else { > + /* > + * We overcommit metadata, so we need to do the > + * btrfs_can_overcommit check here, and we need to pass in > + * BTRFS_RESERVE_NO_FLUSH to give ourselves the most amount of > + * leeway to allow us to mark this block group as read only. > + */ > + if (btrfs_can_overcommit(cache->fs_info, sinfo, num_bytes, > + BTRFS_RESERVE_NO_FLUSH)) > + ret = 0; > + } > + > + if (!ret) { > sinfo->bytes_readonly += num_bytes; > cache->ro++; > list_add_tail(&cache->ro_list, &sinfo->ro_bgs); > - ret = 0; > } > out: > spin_unlock(&cache->lock); > @@ -1225,9 +1241,6 @@ static int inc_block_group_ro(struct btrfs_block_group *cache, int force) > if (ret == -ENOSPC && btrfs_test_opt(cache->fs_info, ENOSPC_DEBUG)) { > btrfs_info(cache->fs_info, > "unable to make block group %llu ro", cache->start); > - btrfs_info(cache->fs_info, > - "sinfo_used=%llu bg_num_bytes=%llu", > - sinfo_used, num_bytes); > btrfs_dump_space_info(cache->fs_info, cache->space_info, 0, 0); > } > return ret; > diff --git a/fs/btrfs/space-info.c b/fs/btrfs/space-info.c > index df5fb68df798..01297c5b2666 100644 > --- a/fs/btrfs/space-info.c > +++ b/fs/btrfs/space-info.c > @@ -159,9 +159,9 @@ static inline u64 calc_global_rsv_need_space(struct btrfs_block_rsv *global) > return (global->size << 1); > } > > -static int can_overcommit(struct btrfs_fs_info *fs_info, > - struct btrfs_space_info *space_info, u64 bytes, > - enum btrfs_reserve_flush_enum flush) > +int btrfs_can_overcommit(struct btrfs_fs_info *fs_info, > + struct btrfs_space_info *space_info, u64 bytes, > + enum btrfs_reserve_flush_enum flush) > { > u64 profile; > u64 avail; > @@ -226,7 +226,8 @@ void btrfs_try_granting_tickets(struct btrfs_fs_info *fs_info, > > /* Check and see if our ticket can be satisified now. */ > if ((used + ticket->bytes <= space_info->total_bytes) || > - can_overcommit(fs_info, space_info, ticket->bytes, flush)) { > + btrfs_can_overcommit(fs_info, space_info, ticket->bytes, > + flush)) { > btrfs_space_info_update_bytes_may_use(fs_info, > space_info, > ticket->bytes); > @@ -639,14 +640,14 @@ btrfs_calc_reclaim_metadata_size(struct btrfs_fs_info *fs_info, > return to_reclaim; > > to_reclaim = min_t(u64, num_online_cpus() * SZ_1M, SZ_16M); > - if (can_overcommit(fs_info, space_info, to_reclaim, > - BTRFS_RESERVE_FLUSH_ALL)) > + if (btrfs_can_overcommit(fs_info, space_info, to_reclaim, > + BTRFS_RESERVE_FLUSH_ALL)) > return 0; > > used = btrfs_space_info_used(space_info, true); > > - if (can_overcommit(fs_info, space_info, SZ_1M, > - BTRFS_RESERVE_FLUSH_ALL)) > + if (btrfs_can_overcommit(fs_info, space_info, SZ_1M, > + BTRFS_RESERVE_FLUSH_ALL)) > expected = div_factor_fine(space_info->total_bytes, 95); > else > expected = div_factor_fine(space_info->total_bytes, 90); > @@ -1005,7 +1006,7 @@ static int __reserve_metadata_bytes(struct btrfs_fs_info *fs_info, > */ > if (!pending_tickets && > ((used + orig_bytes <= space_info->total_bytes) || > - can_overcommit(fs_info, space_info, orig_bytes, flush))) { > + btrfs_can_overcommit(fs_info, space_info, orig_bytes, flush))) { > btrfs_space_info_update_bytes_may_use(fs_info, space_info, > orig_bytes); > ret = 0; > diff --git a/fs/btrfs/space-info.h b/fs/btrfs/space-info.h > index 1a349e3f9cc1..24514cd2c6c1 100644 > --- a/fs/btrfs/space-info.h > +++ b/fs/btrfs/space-info.h > @@ -127,6 +127,9 @@ int btrfs_reserve_metadata_bytes(struct btrfs_root *root, > enum btrfs_reserve_flush_enum flush); > void btrfs_try_granting_tickets(struct btrfs_fs_info *fs_info, > struct btrfs_space_info *space_info); > +int btrfs_can_overcommit(struct btrfs_fs_info *fs_info, > + struct btrfs_space_info *space_info, u64 bytes, > + enum btrfs_reserve_flush_enum flush); > > static inline void btrfs_space_info_free_bytes_may_use( > struct btrfs_fs_info *fs_info, >
diff --git a/fs/btrfs/block-group.c b/fs/btrfs/block-group.c index 5961411500ed..ca55eb6758d1 100644 --- a/fs/btrfs/block-group.c +++ b/fs/btrfs/block-group.c @@ -1184,7 +1184,6 @@ static int inc_block_group_ro(struct btrfs_block_group *cache, int force) { struct btrfs_space_info *sinfo = cache->space_info; u64 num_bytes; - u64 sinfo_used; int ret = -ENOSPC; spin_lock(&sinfo->lock); @@ -1205,19 +1204,36 @@ static int inc_block_group_ro(struct btrfs_block_group *cache, int force) num_bytes = cache->length - cache->reserved - cache->pinned - cache->bytes_super - cache->used; - sinfo_used = btrfs_space_info_used(sinfo, true); /* - * sinfo_used + num_bytes should always <= sinfo->total_bytes. - * - * Here we make sure if we mark this bg RO, we still have enough - * free space as buffer. + * Data never overcommits, even in mixed mode, so do just the straight + * check of left over space in how much we have allocated. */ - if (sinfo_used + num_bytes <= sinfo->total_bytes) { + if (sinfo->flags & BTRFS_BLOCK_GROUP_DATA) { + u64 sinfo_used = btrfs_space_info_used(sinfo, true); + + /* + * Here we make sure if we mark this bg RO, we still have enough + * free space as buffer. + */ + if (sinfo_used + num_bytes <= sinfo->total_bytes) + ret = 0; + } else { + /* + * We overcommit metadata, so we need to do the + * btrfs_can_overcommit check here, and we need to pass in + * BTRFS_RESERVE_NO_FLUSH to give ourselves the most amount of + * leeway to allow us to mark this block group as read only. + */ + if (btrfs_can_overcommit(cache->fs_info, sinfo, num_bytes, + BTRFS_RESERVE_NO_FLUSH)) + ret = 0; + } + + if (!ret) { sinfo->bytes_readonly += num_bytes; cache->ro++; list_add_tail(&cache->ro_list, &sinfo->ro_bgs); - ret = 0; } out: spin_unlock(&cache->lock); @@ -1225,9 +1241,6 @@ static int inc_block_group_ro(struct btrfs_block_group *cache, int force) if (ret == -ENOSPC && btrfs_test_opt(cache->fs_info, ENOSPC_DEBUG)) { btrfs_info(cache->fs_info, "unable to make block group %llu ro", cache->start); - btrfs_info(cache->fs_info, - "sinfo_used=%llu bg_num_bytes=%llu", - sinfo_used, num_bytes); btrfs_dump_space_info(cache->fs_info, cache->space_info, 0, 0); } return ret; diff --git a/fs/btrfs/space-info.c b/fs/btrfs/space-info.c index df5fb68df798..01297c5b2666 100644 --- a/fs/btrfs/space-info.c +++ b/fs/btrfs/space-info.c @@ -159,9 +159,9 @@ static inline u64 calc_global_rsv_need_space(struct btrfs_block_rsv *global) return (global->size << 1); } -static int can_overcommit(struct btrfs_fs_info *fs_info, - struct btrfs_space_info *space_info, u64 bytes, - enum btrfs_reserve_flush_enum flush) +int btrfs_can_overcommit(struct btrfs_fs_info *fs_info, + struct btrfs_space_info *space_info, u64 bytes, + enum btrfs_reserve_flush_enum flush) { u64 profile; u64 avail; @@ -226,7 +226,8 @@ void btrfs_try_granting_tickets(struct btrfs_fs_info *fs_info, /* Check and see if our ticket can be satisified now. */ if ((used + ticket->bytes <= space_info->total_bytes) || - can_overcommit(fs_info, space_info, ticket->bytes, flush)) { + btrfs_can_overcommit(fs_info, space_info, ticket->bytes, + flush)) { btrfs_space_info_update_bytes_may_use(fs_info, space_info, ticket->bytes); @@ -639,14 +640,14 @@ btrfs_calc_reclaim_metadata_size(struct btrfs_fs_info *fs_info, return to_reclaim; to_reclaim = min_t(u64, num_online_cpus() * SZ_1M, SZ_16M); - if (can_overcommit(fs_info, space_info, to_reclaim, - BTRFS_RESERVE_FLUSH_ALL)) + if (btrfs_can_overcommit(fs_info, space_info, to_reclaim, + BTRFS_RESERVE_FLUSH_ALL)) return 0; used = btrfs_space_info_used(space_info, true); - if (can_overcommit(fs_info, space_info, SZ_1M, - BTRFS_RESERVE_FLUSH_ALL)) + if (btrfs_can_overcommit(fs_info, space_info, SZ_1M, + BTRFS_RESERVE_FLUSH_ALL)) expected = div_factor_fine(space_info->total_bytes, 95); else expected = div_factor_fine(space_info->total_bytes, 90); @@ -1005,7 +1006,7 @@ static int __reserve_metadata_bytes(struct btrfs_fs_info *fs_info, */ if (!pending_tickets && ((used + orig_bytes <= space_info->total_bytes) || - can_overcommit(fs_info, space_info, orig_bytes, flush))) { + btrfs_can_overcommit(fs_info, space_info, orig_bytes, flush))) { btrfs_space_info_update_bytes_may_use(fs_info, space_info, orig_bytes); ret = 0; diff --git a/fs/btrfs/space-info.h b/fs/btrfs/space-info.h index 1a349e3f9cc1..24514cd2c6c1 100644 --- a/fs/btrfs/space-info.h +++ b/fs/btrfs/space-info.h @@ -127,6 +127,9 @@ int btrfs_reserve_metadata_bytes(struct btrfs_root *root, enum btrfs_reserve_flush_enum flush); void btrfs_try_granting_tickets(struct btrfs_fs_info *fs_info, struct btrfs_space_info *space_info); +int btrfs_can_overcommit(struct btrfs_fs_info *fs_info, + struct btrfs_space_info *space_info, u64 bytes, + enum btrfs_reserve_flush_enum flush); static inline void btrfs_space_info_free_bytes_may_use( struct btrfs_fs_info *fs_info,
inc_block_group_ro does a calculation to see if we have enough room left over if we mark this block group as read only in order to see if it's ok to mark the block group as read only. The problem is this calculation _only_ works for data, where our used is always less than our total. For metadata we will overcommit, so this will almost always fail for metadata. Fix this by exporting btrfs_can_overcommit, and then see if we have enough space to remove the remaining free space in the block group we are trying to mark read only. If we do then we can mark this block group as read only. Signed-off-by: Josef Bacik <josef@toxicpanda.com> --- fs/btrfs/block-group.c | 35 ++++++++++++++++++++++++----------- fs/btrfs/space-info.c | 19 ++++++++++--------- fs/btrfs/space-info.h | 3 +++ 3 files changed, 37 insertions(+), 20 deletions(-)