btrfs: get rid of block group caching progress logic

struct btrfs_caching_ctl::progress and struct
btrfs_block_group::last_byte_to_unpin were previously needed to ensure
that unpin_extent_range() didn't return a range to the free space cache
before the caching thread had a chance to cache that range. However, the
commit "btrfs: fix space cache corruption and potential double
allocations" made it so that we always synchronously cache the block
group at the time that we pin the extent, so this machinery is no longer
necessary.

Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/fs/btrfs/block-group.c b/fs/btrfs/block-group.c
index 9d549a117d725a6c356d3d19040b8a4cb20e2b11..151a45d31c041ed3c69f7d16aabed72a63f55c4e 100644 (file)
--- a/fs/btrfs/block-group.c
+++ b/fs/btrfs/block-group.c
@@ -593,8 +593,6 @@ next:
 
                        if (need_resched() ||
                            rwsem_is_contended(&fs_info->commit_root_sem)) {
-                               if (wakeup)
-                                       caching_ctl->progress = last;
                                btrfs_release_path(path);
                                up_read(&fs_info->commit_root_sem);
                                mutex_unlock(&caching_ctl->mutex);
@@ -618,9 +616,6 @@ next:
                        key.objectid = last;
                        key.offset = 0;
                        key.type = BTRFS_EXTENT_ITEM_KEY;
-
-                       if (wakeup)
-                               caching_ctl->progress = last;
                        btrfs_release_path(path);
                        goto next;
                }
@@ -655,7 +650,6 @@ next:
 
        total_found += add_new_free_space(block_group, last,
                                block_group->start + block_group->length);
-       caching_ctl->progress = (u64)-1;
 
 out:
        btrfs_free_path(path);
@@ -725,8 +719,6 @@ done:
        }
 #endif
 
-       caching_ctl->progress = (u64)-1;
-
        up_read(&fs_info->commit_root_sem);
        btrfs_free_excluded_extents(block_group);
        mutex_unlock(&caching_ctl->mutex);
@@ -755,7 +747,6 @@ int btrfs_cache_block_group(struct btrfs_block_group *cache, bool wait)
        mutex_init(&caching_ctl->mutex);
        init_waitqueue_head(&caching_ctl->wait);
        caching_ctl->block_group = cache;
-       caching_ctl->progress = cache->start;
        refcount_set(&caching_ctl->count, 2);
        btrfs_init_work(&caching_ctl->work, caching_thread, NULL, NULL);
 
@@ -2075,11 +2066,9 @@ static int read_one_block_group(struct btrfs_fs_info *info,
                /* Should not have any excluded extents. Just in case, though. */
                btrfs_free_excluded_extents(cache);
        } else if (cache->length == cache->used) {
-               cache->last_byte_to_unpin = (u64)-1;
                cache->cached = BTRFS_CACHE_FINISHED;
                btrfs_free_excluded_extents(cache);
        } else if (cache->used == 0) {
-               cache->last_byte_to_unpin = (u64)-1;
                cache->cached = BTRFS_CACHE_FINISHED;
                add_new_free_space(cache, cache->start,
                                   cache->start + cache->length);
@@ -2135,7 +2124,6 @@ static int fill_dummy_bgs(struct btrfs_fs_info *fs_info)
                /* Fill dummy cache as FULL */
                bg->length = em->len;
                bg->flags = map->type;
-               bg->last_byte_to_unpin = (u64)-1;
                bg->cached = BTRFS_CACHE_FINISHED;
                bg->used = em->len;
                bg->flags = map->type;
@@ -2481,7 +2469,6 @@ struct btrfs_block_group *btrfs_make_block_group(struct btrfs_trans_handle *tran
        set_free_space_tree_thresholds(cache);
        cache->used = bytes_used;
        cache->flags = type;
-       cache->last_byte_to_unpin = (u64)-1;
        cache->cached = BTRFS_CACHE_FINISHED;
        cache->global_root_id = calculate_global_root_id(fs_info, cache->start);
 

diff --git a/fs/btrfs/block-group.h b/fs/btrfs/block-group.h
index 6d5ce78c69567c8e21276b20b0b83603ca4ae604..f48db81d1d560658b161646b9fc02bff487bd12b 100644 (file)
--- a/fs/btrfs/block-group.h
+++ b/fs/btrfs/block-group.h
@@ -63,7 +63,6 @@ struct btrfs_caching_control {
        wait_queue_head_t wait;
        struct btrfs_work work;
        struct btrfs_block_group *block_group;
-       u64 progress;
        refcount_t count;
 };
 
@@ -115,7 +114,6 @@ struct btrfs_block_group {
        /* Cache tracking stuff */
        int cached;
        struct btrfs_caching_control *caching_ctl;
-       u64 last_byte_to_unpin;
 
        struct btrfs_space_info *space_info;
 

diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 86ac953c69ac41ffb2704b51932ebd1d0ca821f5..bcd0e72cded303daedd8418e4d9268a678b64e12 100644 (file)
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -2686,13 +2686,8 @@ static int unpin_extent_range(struct btrfs_fs_info *fs_info,
                len = cache->start + cache->length - start;
                len = min(len, end + 1 - start);
 
-               down_read(&fs_info->commit_root_sem);
-               if (start < cache->last_byte_to_unpin && return_free_space) {
-                       u64 add_len = min(len, cache->last_byte_to_unpin - start);
-
-                       btrfs_add_free_space(cache, start, add_len);
-               }
-               up_read(&fs_info->commit_root_sem);
+               if (return_free_space)
+                       btrfs_add_free_space(cache, start, len);
 
                start += len;
                total_unpinned += len;

diff --git a/fs/btrfs/free-space-tree.c b/fs/btrfs/free-space-tree.c
index 1bf89aa672160b264469c59e486bbcaf3a7768b5..367bcfcf68f51eb085f669d989ba98b7885cdd26 100644 (file)
--- a/fs/btrfs/free-space-tree.c
+++ b/fs/btrfs/free-space-tree.c
@@ -1453,8 +1453,6 @@ static int load_free_space_bitmaps(struct btrfs_caching_control *caching_ctl,
                ASSERT(key.type == BTRFS_FREE_SPACE_BITMAP_KEY);
                ASSERT(key.objectid < end && key.objectid + key.offset <= end);
 
-               caching_ctl->progress = key.objectid;
-
                offset = key.objectid;
                while (offset < key.objectid + key.offset) {
                        bit = free_space_test_bit(block_group, path, offset);
@@ -1490,8 +1488,6 @@ static int load_free_space_bitmaps(struct btrfs_caching_control *caching_ctl,
                goto out;
        }
 
-       caching_ctl->progress = (u64)-1;
-
        ret = 0;
 out:
        return ret;
@@ -1531,8 +1527,6 @@ static int load_free_space_extents(struct btrfs_caching_control *caching_ctl,
                ASSERT(key.type == BTRFS_FREE_SPACE_EXTENT_KEY);
                ASSERT(key.objectid < end && key.objectid + key.offset <= end);
 
-               caching_ctl->progress = key.objectid;
-
                total_found += add_new_free_space(block_group, key.objectid,
                                                  key.objectid + key.offset);
                if (total_found > CACHING_CTL_WAKE_UP) {
@@ -1552,8 +1546,6 @@ static int load_free_space_extents(struct btrfs_caching_control *caching_ctl,
                goto out;
        }
 
-       caching_ctl->progress = (u64)-1;
-
        ret = 0;
 out:
        return ret;

diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
index 6e3b2cb6a04afa3fb9bf032f44bf7c8f6dfb5c55..4c87bf2abc1424cec569278daaffec964a7d031a 100644 (file)
--- a/fs/btrfs/transaction.c
+++ b/fs/btrfs/transaction.c
@@ -161,7 +161,6 @@ static noinline void switch_commit_roots(struct btrfs_trans_handle *trans)
        struct btrfs_transaction *cur_trans = trans->transaction;
        struct btrfs_fs_info *fs_info = trans->fs_info;
        struct btrfs_root *root, *tmp;
-       struct btrfs_caching_control *caching_ctl, *next;
 
        /*
         * At this point no one can be using this transaction to modify any tree
@@ -196,46 +195,6 @@ static noinline void switch_commit_roots(struct btrfs_trans_handle *trans)
        }
        spin_unlock(&cur_trans->dropped_roots_lock);
 
-       /*
-        * We have to update the last_byte_to_unpin under the commit_root_sem,
-        * at the same time we swap out the commit roots.
-        *
-        * This is because we must have a real view of the last spot the caching
-        * kthreads were while caching.  Consider the following views of the
-        * extent tree for a block group
-        *
-        * commit root
-        * +----+----+----+----+----+----+----+
-        * |\\\\|    |\\\\|\\\\|    |\\\\|\\\\|
-        * +----+----+----+----+----+----+----+
-        * 0    1    2    3    4    5    6    7
-        *
-        * new commit root
-        * +----+----+----+----+----+----+----+
-        * |    |    |    |\\\\|    |    |\\\\|
-        * +----+----+----+----+----+----+----+
-        * 0    1    2    3    4    5    6    7
-        *
-        * If the cache_ctl->progress was at 3, then we are only allowed to
-        * unpin [0,1) and [2,3], because the caching thread has already
-        * processed those extents.  We are not allowed to unpin [5,6), because
-        * the caching thread will re-start it's search from 3, and thus find
-        * the hole from [4,6) to add to the free space cache.
-        */
-       write_lock(&fs_info->block_group_cache_lock);
-       list_for_each_entry_safe(caching_ctl, next,
-                                &fs_info->caching_block_groups, list) {
-               struct btrfs_block_group *cache = caching_ctl->block_group;
-
-               if (btrfs_block_group_done(cache)) {
-                       cache->last_byte_to_unpin = (u64)-1;
-                       list_del_init(&caching_ctl->list);
-                       btrfs_put_caching_control(caching_ctl);
-               } else {
-                       cache->last_byte_to_unpin = caching_ctl->progress;
-               }
-       }
-       write_unlock(&fs_info->block_group_cache_lock);
        up_write(&fs_info->commit_root_sem);
 }
 

diff --git a/fs/btrfs/zoned.c b/fs/btrfs/zoned.c
index 9f31865e6003d1646f9d094ce0117cd4c815749a..eff14ffd45cb834d49a16cdacc4b918d1d4d4947 100644 (file)
--- a/fs/btrfs/zoned.c
+++ b/fs/btrfs/zoned.c
@@ -1566,7 +1566,6 @@ void btrfs_calc_zone_unusable(struct btrfs_block_group *cache)
        free = cache->zone_capacity - cache->alloc_offset;
 
        /* We only need ->free_space in ALLOC_SEQ block groups */
-       cache->last_byte_to_unpin = (u64)-1;
        cache->cached = BTRFS_CACHE_FINISHED;
        cache->free_space_ctl->free_space = free;
        cache->zone_unusable = unusable;