From 91435650c233b93e0da389db74f4b2c11c5ad2d4 Mon Sep 17 00:00:00 2001 From: Chris Mason Date: Wed, 16 Feb 2011 13:10:41 -0500 Subject: Btrfs: put ENOSPC debugging under a mount option ENOSPC in btrfs is getting to the point where the extra debugging isn't required. I've put it under mount -o enospc_debug just in case someone is having difficult problems. Signed-off-by: Chris Mason --- fs/btrfs/extent-tree.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'fs/btrfs/extent-tree.c') diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c index a7aaa10c530..d375fc04a06 100644 --- a/fs/btrfs/extent-tree.c +++ b/fs/btrfs/extent-tree.c @@ -5377,7 +5377,7 @@ again: num_bytes, data, 1); goto again; } - if (ret == -ENOSPC) { + if (ret == -ENOSPC && btrfs_test_opt(root, ENOSPC_DEBUG)) { struct btrfs_space_info *sinfo; sinfo = __find_space_info(root->fs_info, data); -- cgit v1.2.3 From c87f08ca44e83b2c8d28f63f9c33f3a270a04bbe Mon Sep 17 00:00:00 2001 From: Chris Mason Date: Wed, 16 Feb 2011 13:57:04 -0500 Subject: Btrfs: allow balance to explicitly allocate chunks as it relocates Btrfs device shrinking and balancing ends up reallocating all the blocks in order to allow COW to move them to new destinations. It is somewhat awkward in terms of ENOSPC because most of the enospc code is built around the idea that some operation on a reference counted tree triggers allocations in the non-reference counted trees. This commit changes the balancing code to deal with enospc by trying to allocate a new chunk. If that allocation succeeds, we go ahead and retry whatever failed due to enospc. Signed-off-by: Chris Mason --- fs/btrfs/ctree.h | 2 ++ fs/btrfs/extent-tree.c | 7 +++++++ fs/btrfs/relocation.c | 13 ++++++++++++- 3 files changed, 21 insertions(+), 1 deletion(-) (limited to 'fs/btrfs/extent-tree.c') diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h index 6297701bc19..28188a786da 100644 --- a/fs/btrfs/ctree.h +++ b/fs/btrfs/ctree.h @@ -2219,6 +2219,8 @@ int btrfs_error_unpin_extent_range(struct btrfs_root *root, u64 start, u64 end); int btrfs_error_discard_extent(struct btrfs_root *root, u64 bytenr, u64 num_bytes); +int btrfs_force_chunk_alloc(struct btrfs_trans_handle *trans, + struct btrfs_root *root, u64 type); /* ctree.c */ int btrfs_bin_search(struct extent_buffer *eb, struct btrfs_key *key, diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c index d375fc04a06..100e409e905 100644 --- a/fs/btrfs/extent-tree.c +++ b/fs/btrfs/extent-tree.c @@ -8066,6 +8066,13 @@ out: return ret; } +int btrfs_force_chunk_alloc(struct btrfs_trans_handle *trans, + struct btrfs_root *root, u64 type) +{ + u64 alloc_flags = get_alloc_profile(root, type); + return do_chunk_alloc(trans, root, 2 * 1024 * 1024, alloc_flags, 1); +} + /* * helper to account the unused space of all the readonly block group in the * list. takes mirrors into account. diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c index 0825e4ed944..31ade5802ae 100644 --- a/fs/btrfs/relocation.c +++ b/fs/btrfs/relocation.c @@ -3654,6 +3654,7 @@ static noinline_for_stack int relocate_block_group(struct reloc_control *rc) u32 item_size; int ret; int err = 0; + int progress = 0; path = btrfs_alloc_path(); if (!path) @@ -3666,9 +3667,10 @@ static noinline_for_stack int relocate_block_group(struct reloc_control *rc) } while (1) { + progress++; trans = btrfs_start_transaction(rc->extent_root, 0); BUG_ON(IS_ERR(trans)); - +restart: if (update_backref_cache(trans, &rc->backref_cache)) { btrfs_end_transaction(trans, rc->extent_root); continue; @@ -3781,6 +3783,15 @@ static noinline_for_stack int relocate_block_group(struct reloc_control *rc) } } } + if (trans && progress && err == -ENOSPC) { + ret = btrfs_force_chunk_alloc(trans, rc->extent_root, + rc->block_group->flags); + if (ret == 0) { + err = 0; + progress = 0; + goto restart; + } + } btrfs_release_path(rc->extent_root, path); clear_extent_bits(&rc->processed_blocks, 0, (u64)-1, EXTENT_DIRTY, -- cgit v1.2.3 From 36e39c40b3facc9b489a13f1d301fc53ff6960a3 Mon Sep 17 00:00:00 2001 From: Chris Mason Date: Sat, 12 Mar 2011 07:08:42 -0500 Subject: Btrfs: break out of shrink_delalloc earlier Josef had changed shrink_delalloc to exit after three shrink attempts, which wasn't quite enough because new writers could race in and steal free space. But it also fixed deadlocks and stalls as we tried to recover delalloc reservations. The code was tweaked to loop 1024 times, and would reset the counter any time a small amount of progress was made. This was too drastic, and with a lot of writers we can end up stuck in shrink_delalloc forever. The shrink_delalloc loop is fairly complex because the caller is looping too, and the caller will go ahead and force a transaction commit to make sure we reclaim space. This reworks things to exit shrink_delalloc when we've forced some writeback and the delalloc reservations have gone down. This means the writeback has not just started but has also finished at least some of the metadata changes required to reclaim delalloc space. If we've got this wrong, we're returning ENOSPC too early, which is a big improvement over the current behavior of hanging the machine. Test 224 in xfstests hammers on this nicely, and with 1000 writers trying to fill a 1GB drive we get our first ENOSPC at 93% full. The other writers are able to continue until we get 100%. This is a worst case test for btrfs because the 1000 writers are doing small IO, and the small FS size means we don't have a lot of room for metadata chunks. Signed-off-by: Chris Mason --- fs/btrfs/ctree.h | 9 +++++++++ fs/btrfs/extent-tree.c | 35 +++++++++++++++++++++++------------ 2 files changed, 32 insertions(+), 12 deletions(-) (limited to 'fs/btrfs/extent-tree.c') diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h index 28188a786da..8b4b9d158a0 100644 --- a/fs/btrfs/ctree.h +++ b/fs/btrfs/ctree.h @@ -729,6 +729,15 @@ struct btrfs_space_info { u64 disk_total; /* total bytes on disk, takes mirrors into account */ + /* + * we bump reservation progress every time we decrement + * bytes_reserved. This way people waiting for reservations + * know something good has happened and they can check + * for progress. The number here isn't to be trusted, it + * just shows reclaim activity + */ + unsigned long reservation_progress; + int full; /* indicates that we cannot allocate any more chunks for this space */ int force_alloc; /* set if we need to force a chunk alloc for diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c index 100e409e905..f1db57d4a01 100644 --- a/fs/btrfs/extent-tree.c +++ b/fs/btrfs/extent-tree.c @@ -3343,15 +3343,16 @@ static int shrink_delalloc(struct btrfs_trans_handle *trans, u64 max_reclaim; u64 reclaimed = 0; long time_left; - int pause = 1; int nr_pages = (2 * 1024 * 1024) >> PAGE_CACHE_SHIFT; int loops = 0; + unsigned long progress; block_rsv = &root->fs_info->delalloc_block_rsv; space_info = block_rsv->space_info; smp_mb(); reserved = space_info->bytes_reserved; + progress = space_info->reservation_progress; if (reserved == 0) return 0; @@ -3366,31 +3367,36 @@ static int shrink_delalloc(struct btrfs_trans_handle *trans, writeback_inodes_sb_nr_if_idle(root->fs_info->sb, nr_pages); spin_lock(&space_info->lock); - if (reserved > space_info->bytes_reserved) { - loops = 0; + if (reserved > space_info->bytes_reserved) reclaimed += reserved - space_info->bytes_reserved; - } else { - loops++; - } reserved = space_info->bytes_reserved; spin_unlock(&space_info->lock); + loops++; + if (reserved == 0 || reclaimed >= max_reclaim) break; if (trans && trans->transaction->blocked) return -EAGAIN; - __set_current_state(TASK_INTERRUPTIBLE); - time_left = schedule_timeout(pause); + time_left = schedule_timeout_interruptible(1); /* We were interrupted, exit */ if (time_left) break; - pause <<= 1; - if (pause > HZ / 10) - pause = HZ / 10; + /* we've kicked the IO a few times, if anything has been freed, + * exit. There is no sense in looping here for a long time + * when we really need to commit the transaction, or there are + * just too many writers without enough free space + */ + + if (loops > 3) { + smp_mb(); + if (progress != space_info->reservation_progress) + break; + } } return reclaimed >= to_reclaim; @@ -3613,6 +3619,7 @@ void block_rsv_release_bytes(struct btrfs_block_rsv *block_rsv, if (num_bytes) { spin_lock(&space_info->lock); space_info->bytes_reserved -= num_bytes; + space_info->reservation_progress++; spin_unlock(&space_info->lock); } } @@ -3845,6 +3852,7 @@ static void update_global_block_rsv(struct btrfs_fs_info *fs_info) if (block_rsv->reserved >= block_rsv->size) { num_bytes = block_rsv->reserved - block_rsv->size; sinfo->bytes_reserved -= num_bytes; + sinfo->reservation_progress++; block_rsv->reserved = block_rsv->size; block_rsv->full = 1; } @@ -4006,7 +4014,6 @@ int btrfs_delalloc_reserve_metadata(struct inode *inode, u64 num_bytes) to_reserve = 0; } spin_unlock(&BTRFS_I(inode)->accounting_lock); - to_reserve += calc_csum_metadata_size(inode, num_bytes); ret = reserve_metadata_bytes(NULL, root, block_rsv, to_reserve, 1); if (ret) @@ -4134,6 +4141,7 @@ static int update_block_group(struct btrfs_trans_handle *trans, btrfs_set_block_group_used(&cache->item, old_val); cache->reserved -= num_bytes; cache->space_info->bytes_reserved -= num_bytes; + cache->space_info->reservation_progress++; cache->space_info->bytes_used += num_bytes; cache->space_info->disk_used += num_bytes * factor; spin_unlock(&cache->lock); @@ -4185,6 +4193,7 @@ static int pin_down_extent(struct btrfs_root *root, if (reserved) { cache->reserved -= num_bytes; cache->space_info->bytes_reserved -= num_bytes; + cache->space_info->reservation_progress++; } spin_unlock(&cache->lock); spin_unlock(&cache->space_info->lock); @@ -4235,6 +4244,7 @@ static int update_reserved_bytes(struct btrfs_block_group_cache *cache, space_info->bytes_readonly += num_bytes; cache->reserved -= num_bytes; space_info->bytes_reserved -= num_bytes; + space_info->reservation_progress++; } spin_unlock(&cache->lock); spin_unlock(&space_info->lock); @@ -4713,6 +4723,7 @@ void btrfs_free_tree_block(struct btrfs_trans_handle *trans, if (ret) { spin_lock(&cache->space_info->lock); cache->space_info->bytes_reserved -= buf->len; + cache->space_info->reservation_progress++; spin_unlock(&cache->space_info->lock); } goto out; -- cgit v1.2.3