Update Linux to v5.4.2
Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/fs/btrfs/block-group.c b/fs/btrfs/block-group.c
new file mode 100644
index 0000000..670700c
--- /dev/null
+++ b/fs/btrfs/block-group.c
@@ -0,0 +1,3174 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include "misc.h"
+#include "ctree.h"
+#include "block-group.h"
+#include "space-info.h"
+#include "disk-io.h"
+#include "free-space-cache.h"
+#include "free-space-tree.h"
+#include "disk-io.h"
+#include "volumes.h"
+#include "transaction.h"
+#include "ref-verify.h"
+#include "sysfs.h"
+#include "tree-log.h"
+#include "delalloc-space.h"
+
+/*
+ * Return target flags in extended format or 0 if restripe for this chunk_type
+ * is not in progress
+ *
+ * Should be called with balance_lock held
+ */
+static u64 get_restripe_target(struct btrfs_fs_info *fs_info, u64 flags)
+{
+ struct btrfs_balance_control *bctl = fs_info->balance_ctl;
+ u64 target = 0;
+
+ if (!bctl)
+ return 0;
+
+ if (flags & BTRFS_BLOCK_GROUP_DATA &&
+ bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT) {
+ target = BTRFS_BLOCK_GROUP_DATA | bctl->data.target;
+ } else if (flags & BTRFS_BLOCK_GROUP_SYSTEM &&
+ bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) {
+ target = BTRFS_BLOCK_GROUP_SYSTEM | bctl->sys.target;
+ } else if (flags & BTRFS_BLOCK_GROUP_METADATA &&
+ bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT) {
+ target = BTRFS_BLOCK_GROUP_METADATA | bctl->meta.target;
+ }
+
+ return target;
+}
+
+/*
+ * @flags: available profiles in extended format (see ctree.h)
+ *
+ * Return reduced profile in chunk format. If profile changing is in progress
+ * (either running or paused) picks the target profile (if it's already
+ * available), otherwise falls back to plain reducing.
+ */
+static u64 btrfs_reduce_alloc_profile(struct btrfs_fs_info *fs_info, u64 flags)
+{
+ u64 num_devices = fs_info->fs_devices->rw_devices;
+ u64 target;
+ u64 raid_type;
+ u64 allowed = 0;
+
+ /*
+ * See if restripe for this chunk_type is in progress, if so try to
+ * reduce to the target profile
+ */
+ spin_lock(&fs_info->balance_lock);
+ target = get_restripe_target(fs_info, flags);
+ if (target) {
+ /* Pick target profile only if it's already available */
+ if ((flags & target) & BTRFS_EXTENDED_PROFILE_MASK) {
+ spin_unlock(&fs_info->balance_lock);
+ return extended_to_chunk(target);
+ }
+ }
+ spin_unlock(&fs_info->balance_lock);
+
+ /* First, mask out the RAID levels which aren't possible */
+ for (raid_type = 0; raid_type < BTRFS_NR_RAID_TYPES; raid_type++) {
+ if (num_devices >= btrfs_raid_array[raid_type].devs_min)
+ allowed |= btrfs_raid_array[raid_type].bg_flag;
+ }
+ allowed &= flags;
+
+ if (allowed & BTRFS_BLOCK_GROUP_RAID6)
+ allowed = BTRFS_BLOCK_GROUP_RAID6;
+ else if (allowed & BTRFS_BLOCK_GROUP_RAID5)
+ allowed = BTRFS_BLOCK_GROUP_RAID5;
+ else if (allowed & BTRFS_BLOCK_GROUP_RAID10)
+ allowed = BTRFS_BLOCK_GROUP_RAID10;
+ else if (allowed & BTRFS_BLOCK_GROUP_RAID1)
+ allowed = BTRFS_BLOCK_GROUP_RAID1;
+ else if (allowed & BTRFS_BLOCK_GROUP_RAID0)
+ allowed = BTRFS_BLOCK_GROUP_RAID0;
+
+ flags &= ~BTRFS_BLOCK_GROUP_PROFILE_MASK;
+
+ return extended_to_chunk(flags | allowed);
+}
+
+static u64 get_alloc_profile(struct btrfs_fs_info *fs_info, u64 orig_flags)
+{
+ unsigned seq;
+ u64 flags;
+
+ do {
+ flags = orig_flags;
+ seq = read_seqbegin(&fs_info->profiles_lock);
+
+ if (flags & BTRFS_BLOCK_GROUP_DATA)
+ flags |= fs_info->avail_data_alloc_bits;
+ else if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
+ flags |= fs_info->avail_system_alloc_bits;
+ else if (flags & BTRFS_BLOCK_GROUP_METADATA)
+ flags |= fs_info->avail_metadata_alloc_bits;
+ } while (read_seqretry(&fs_info->profiles_lock, seq));
+
+ return btrfs_reduce_alloc_profile(fs_info, flags);
+}
+
+u64 btrfs_get_alloc_profile(struct btrfs_fs_info *fs_info, u64 orig_flags)
+{
+ return get_alloc_profile(fs_info, orig_flags);
+}
+
+void btrfs_get_block_group(struct btrfs_block_group_cache *cache)
+{
+ atomic_inc(&cache->count);
+}
+
+void btrfs_put_block_group(struct btrfs_block_group_cache *cache)
+{
+ if (atomic_dec_and_test(&cache->count)) {
+ WARN_ON(cache->pinned > 0);
+ WARN_ON(cache->reserved > 0);
+
+ /*
+ * If not empty, someone is still holding mutex of
+ * full_stripe_lock, which can only be released by caller.
+ * And it will definitely cause use-after-free when caller
+ * tries to release full stripe lock.
+ *
+ * No better way to resolve, but only to warn.
+ */
+ WARN_ON(!RB_EMPTY_ROOT(&cache->full_stripe_locks_root.root));
+ kfree(cache->free_space_ctl);
+ kfree(cache);
+ }
+}
+
+/*
+ * This adds the block group to the fs_info rb tree for the block group cache
+ */
+static int btrfs_add_block_group_cache(struct btrfs_fs_info *info,
+ struct btrfs_block_group_cache *block_group)
+{
+ struct rb_node **p;
+ struct rb_node *parent = NULL;
+ struct btrfs_block_group_cache *cache;
+
+ spin_lock(&info->block_group_cache_lock);
+ p = &info->block_group_cache_tree.rb_node;
+
+ while (*p) {
+ parent = *p;
+ cache = rb_entry(parent, struct btrfs_block_group_cache,
+ cache_node);
+ if (block_group->key.objectid < cache->key.objectid) {
+ p = &(*p)->rb_left;
+ } else if (block_group->key.objectid > cache->key.objectid) {
+ p = &(*p)->rb_right;
+ } else {
+ spin_unlock(&info->block_group_cache_lock);
+ return -EEXIST;
+ }
+ }
+
+ rb_link_node(&block_group->cache_node, parent, p);
+ rb_insert_color(&block_group->cache_node,
+ &info->block_group_cache_tree);
+
+ if (info->first_logical_byte > block_group->key.objectid)
+ info->first_logical_byte = block_group->key.objectid;
+
+ spin_unlock(&info->block_group_cache_lock);
+
+ return 0;
+}
+
+/*
+ * This will return the block group at or after bytenr if contains is 0, else
+ * it will return the block group that contains the bytenr
+ */
+static struct btrfs_block_group_cache *block_group_cache_tree_search(
+ struct btrfs_fs_info *info, u64 bytenr, int contains)
+{
+ struct btrfs_block_group_cache *cache, *ret = NULL;
+ struct rb_node *n;
+ u64 end, start;
+
+ spin_lock(&info->block_group_cache_lock);
+ n = info->block_group_cache_tree.rb_node;
+
+ while (n) {
+ cache = rb_entry(n, struct btrfs_block_group_cache,
+ cache_node);
+ end = cache->key.objectid + cache->key.offset - 1;
+ start = cache->key.objectid;
+
+ if (bytenr < start) {
+ if (!contains && (!ret || start < ret->key.objectid))
+ ret = cache;
+ n = n->rb_left;
+ } else if (bytenr > start) {
+ if (contains && bytenr <= end) {
+ ret = cache;
+ break;
+ }
+ n = n->rb_right;
+ } else {
+ ret = cache;
+ break;
+ }
+ }
+ if (ret) {
+ btrfs_get_block_group(ret);
+ if (bytenr == 0 && info->first_logical_byte > ret->key.objectid)
+ info->first_logical_byte = ret->key.objectid;
+ }
+ spin_unlock(&info->block_group_cache_lock);
+
+ return ret;
+}
+
+/*
+ * Return the block group that starts at or after bytenr
+ */
+struct btrfs_block_group_cache *btrfs_lookup_first_block_group(
+ struct btrfs_fs_info *info, u64 bytenr)
+{
+ return block_group_cache_tree_search(info, bytenr, 0);
+}
+
+/*
+ * Return the block group that contains the given bytenr
+ */
+struct btrfs_block_group_cache *btrfs_lookup_block_group(
+ struct btrfs_fs_info *info, u64 bytenr)
+{
+ return block_group_cache_tree_search(info, bytenr, 1);
+}
+
+struct btrfs_block_group_cache *btrfs_next_block_group(
+ struct btrfs_block_group_cache *cache)
+{
+ struct btrfs_fs_info *fs_info = cache->fs_info;
+ struct rb_node *node;
+
+ spin_lock(&fs_info->block_group_cache_lock);
+
+ /* If our block group was removed, we need a full search. */
+ if (RB_EMPTY_NODE(&cache->cache_node)) {
+ const u64 next_bytenr = cache->key.objectid + cache->key.offset;
+
+ spin_unlock(&fs_info->block_group_cache_lock);
+ btrfs_put_block_group(cache);
+ cache = btrfs_lookup_first_block_group(fs_info, next_bytenr); return cache;
+ }
+ node = rb_next(&cache->cache_node);
+ btrfs_put_block_group(cache);
+ if (node) {
+ cache = rb_entry(node, struct btrfs_block_group_cache,
+ cache_node);
+ btrfs_get_block_group(cache);
+ } else
+ cache = NULL;
+ spin_unlock(&fs_info->block_group_cache_lock);
+ return cache;
+}
+
+bool btrfs_inc_nocow_writers(struct btrfs_fs_info *fs_info, u64 bytenr)
+{
+ struct btrfs_block_group_cache *bg;
+ bool ret = true;
+
+ bg = btrfs_lookup_block_group(fs_info, bytenr);
+ if (!bg)
+ return false;
+
+ spin_lock(&bg->lock);
+ if (bg->ro)
+ ret = false;
+ else
+ atomic_inc(&bg->nocow_writers);
+ spin_unlock(&bg->lock);
+
+ /* No put on block group, done by btrfs_dec_nocow_writers */
+ if (!ret)
+ btrfs_put_block_group(bg);
+
+ return ret;
+}
+
+void btrfs_dec_nocow_writers(struct btrfs_fs_info *fs_info, u64 bytenr)
+{
+ struct btrfs_block_group_cache *bg;
+
+ bg = btrfs_lookup_block_group(fs_info, bytenr);
+ ASSERT(bg);
+ if (atomic_dec_and_test(&bg->nocow_writers))
+ wake_up_var(&bg->nocow_writers);
+ /*
+ * Once for our lookup and once for the lookup done by a previous call
+ * to btrfs_inc_nocow_writers()
+ */
+ btrfs_put_block_group(bg);
+ btrfs_put_block_group(bg);
+}
+
+void btrfs_wait_nocow_writers(struct btrfs_block_group_cache *bg)
+{
+ wait_var_event(&bg->nocow_writers, !atomic_read(&bg->nocow_writers));
+}
+
+void btrfs_dec_block_group_reservations(struct btrfs_fs_info *fs_info,
+ const u64 start)
+{
+ struct btrfs_block_group_cache *bg;
+
+ bg = btrfs_lookup_block_group(fs_info, start);
+ ASSERT(bg);
+ if (atomic_dec_and_test(&bg->reservations))
+ wake_up_var(&bg->reservations);
+ btrfs_put_block_group(bg);
+}
+
+void btrfs_wait_block_group_reservations(struct btrfs_block_group_cache *bg)
+{
+ struct btrfs_space_info *space_info = bg->space_info;
+
+ ASSERT(bg->ro);
+
+ if (!(bg->flags & BTRFS_BLOCK_GROUP_DATA))
+ return;
+
+ /*
+ * Our block group is read only but before we set it to read only,
+ * some task might have had allocated an extent from it already, but it
+ * has not yet created a respective ordered extent (and added it to a
+ * root's list of ordered extents).
+ * Therefore wait for any task currently allocating extents, since the
+ * block group's reservations counter is incremented while a read lock
+ * on the groups' semaphore is held and decremented after releasing
+ * the read access on that semaphore and creating the ordered extent.
+ */
+ down_write(&space_info->groups_sem);
+ up_write(&space_info->groups_sem);
+
+ wait_var_event(&bg->reservations, !atomic_read(&bg->reservations));
+}
+
+struct btrfs_caching_control *btrfs_get_caching_control(
+ struct btrfs_block_group_cache *cache)
+{
+ struct btrfs_caching_control *ctl;
+
+ spin_lock(&cache->lock);
+ if (!cache->caching_ctl) {
+ spin_unlock(&cache->lock);
+ return NULL;
+ }
+
+ ctl = cache->caching_ctl;
+ refcount_inc(&ctl->count);
+ spin_unlock(&cache->lock);
+ return ctl;
+}
+
+void btrfs_put_caching_control(struct btrfs_caching_control *ctl)
+{
+ if (refcount_dec_and_test(&ctl->count))
+ kfree(ctl);
+}
+
+/*
+ * When we wait for progress in the block group caching, its because our
+ * allocation attempt failed at least once. So, we must sleep and let some
+ * progress happen before we try again.
+ *
+ * This function will sleep at least once waiting for new free space to show
+ * up, and then it will check the block group free space numbers for our min
+ * num_bytes. Another option is to have it go ahead and look in the rbtree for
+ * a free extent of a given size, but this is a good start.
+ *
+ * Callers of this must check if cache->cached == BTRFS_CACHE_ERROR before using
+ * any of the information in this block group.
+ */
+void btrfs_wait_block_group_cache_progress(struct btrfs_block_group_cache *cache,
+ u64 num_bytes)
+{
+ struct btrfs_caching_control *caching_ctl;
+
+ caching_ctl = btrfs_get_caching_control(cache);
+ if (!caching_ctl)
+ return;
+
+ wait_event(caching_ctl->wait, btrfs_block_group_cache_done(cache) ||
+ (cache->free_space_ctl->free_space >= num_bytes));
+
+ btrfs_put_caching_control(caching_ctl);
+}
+
+int btrfs_wait_block_group_cache_done(struct btrfs_block_group_cache *cache)
+{
+ struct btrfs_caching_control *caching_ctl;
+ int ret = 0;
+
+ caching_ctl = btrfs_get_caching_control(cache);
+ if (!caching_ctl)
+ return (cache->cached == BTRFS_CACHE_ERROR) ? -EIO : 0;
+
+ wait_event(caching_ctl->wait, btrfs_block_group_cache_done(cache));
+ if (cache->cached == BTRFS_CACHE_ERROR)
+ ret = -EIO;
+ btrfs_put_caching_control(caching_ctl);
+ return ret;
+}
+
+#ifdef CONFIG_BTRFS_DEBUG
+static void fragment_free_space(struct btrfs_block_group_cache *block_group)
+{
+ struct btrfs_fs_info *fs_info = block_group->fs_info;
+ u64 start = block_group->key.objectid;
+ u64 len = block_group->key.offset;
+ u64 chunk = block_group->flags & BTRFS_BLOCK_GROUP_METADATA ?
+ fs_info->nodesize : fs_info->sectorsize;
+ u64 step = chunk << 1;
+
+ while (len > chunk) {
+ btrfs_remove_free_space(block_group, start, chunk);
+ start += step;
+ if (len < step)
+ len = 0;
+ else
+ len -= step;
+ }
+}
+#endif
+
+/*
+ * This is only called by btrfs_cache_block_group, since we could have freed
+ * extents we need to check the pinned_extents for any extents that can't be
+ * used yet since their free space will be released as soon as the transaction
+ * commits.
+ */
+u64 add_new_free_space(struct btrfs_block_group_cache *block_group,
+ u64 start, u64 end)
+{
+ struct btrfs_fs_info *info = block_group->fs_info;
+ u64 extent_start, extent_end, size, total_added = 0;
+ int ret;
+
+ while (start < end) {
+ ret = find_first_extent_bit(info->pinned_extents, start,
+ &extent_start, &extent_end,
+ EXTENT_DIRTY | EXTENT_UPTODATE,
+ NULL);
+ if (ret)
+ break;
+
+ if (extent_start <= start) {
+ start = extent_end + 1;
+ } else if (extent_start > start && extent_start < end) {
+ size = extent_start - start;
+ total_added += size;
+ ret = btrfs_add_free_space(block_group, start,
+ size);
+ BUG_ON(ret); /* -ENOMEM or logic error */
+ start = extent_end + 1;
+ } else {
+ break;
+ }
+ }
+
+ if (start < end) {
+ size = end - start;
+ total_added += size;
+ ret = btrfs_add_free_space(block_group, start, size);
+ BUG_ON(ret); /* -ENOMEM or logic error */
+ }
+
+ return total_added;
+}
+
+static int load_extent_tree_free(struct btrfs_caching_control *caching_ctl)
+{
+ struct btrfs_block_group_cache *block_group = caching_ctl->block_group;
+ struct btrfs_fs_info *fs_info = block_group->fs_info;
+ struct btrfs_root *extent_root = fs_info->extent_root;
+ struct btrfs_path *path;
+ struct extent_buffer *leaf;
+ struct btrfs_key key;
+ u64 total_found = 0;
+ u64 last = 0;
+ u32 nritems;
+ int ret;
+ bool wakeup = true;
+
+ path = btrfs_alloc_path();
+ if (!path)
+ return -ENOMEM;
+
+ last = max_t(u64, block_group->key.objectid, BTRFS_SUPER_INFO_OFFSET);
+
+#ifdef CONFIG_BTRFS_DEBUG
+ /*
+ * If we're fragmenting we don't want to make anybody think we can
+ * allocate from this block group until we've had a chance to fragment
+ * the free space.
+ */
+ if (btrfs_should_fragment_free_space(block_group))
+ wakeup = false;
+#endif
+ /*
+ * We don't want to deadlock with somebody trying to allocate a new
+ * extent for the extent root while also trying to search the extent
+ * root to add free space. So we skip locking and search the commit
+ * root, since its read-only
+ */
+ path->skip_locking = 1;
+ path->search_commit_root = 1;
+ path->reada = READA_FORWARD;
+
+ key.objectid = last;
+ key.offset = 0;
+ key.type = BTRFS_EXTENT_ITEM_KEY;
+
+next:
+ ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
+ if (ret < 0)
+ goto out;
+
+ leaf = path->nodes[0];
+ nritems = btrfs_header_nritems(leaf);
+
+ while (1) {
+ if (btrfs_fs_closing(fs_info) > 1) {
+ last = (u64)-1;
+ break;
+ }
+
+ if (path->slots[0] < nritems) {
+ btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
+ } else {
+ ret = btrfs_find_next_key(extent_root, path, &key, 0, 0);
+ if (ret)
+ break;
+
+ 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);
+ cond_resched();
+ mutex_lock(&caching_ctl->mutex);
+ down_read(&fs_info->commit_root_sem);
+ goto next;
+ }
+
+ ret = btrfs_next_leaf(extent_root, path);
+ if (ret < 0)
+ goto out;
+ if (ret)
+ break;
+ leaf = path->nodes[0];
+ nritems = btrfs_header_nritems(leaf);
+ continue;
+ }
+
+ if (key.objectid < last) {
+ key.objectid = last;
+ key.offset = 0;
+ key.type = BTRFS_EXTENT_ITEM_KEY;
+
+ if (wakeup)
+ caching_ctl->progress = last;
+ btrfs_release_path(path);
+ goto next;
+ }
+
+ if (key.objectid < block_group->key.objectid) {
+ path->slots[0]++;
+ continue;
+ }
+
+ if (key.objectid >= block_group->key.objectid +
+ block_group->key.offset)
+ break;
+
+ if (key.type == BTRFS_EXTENT_ITEM_KEY ||
+ key.type == BTRFS_METADATA_ITEM_KEY) {
+ total_found += add_new_free_space(block_group, last,
+ key.objectid);
+ if (key.type == BTRFS_METADATA_ITEM_KEY)
+ last = key.objectid +
+ fs_info->nodesize;
+ else
+ last = key.objectid + key.offset;
+
+ if (total_found > CACHING_CTL_WAKE_UP) {
+ total_found = 0;
+ if (wakeup)
+ wake_up(&caching_ctl->wait);
+ }
+ }
+ path->slots[0]++;
+ }
+ ret = 0;
+
+ total_found += add_new_free_space(block_group, last,
+ block_group->key.objectid +
+ block_group->key.offset);
+ caching_ctl->progress = (u64)-1;
+
+out:
+ btrfs_free_path(path);
+ return ret;
+}
+
+static noinline void caching_thread(struct btrfs_work *work)
+{
+ struct btrfs_block_group_cache *block_group;
+ struct btrfs_fs_info *fs_info;
+ struct btrfs_caching_control *caching_ctl;
+ int ret;
+
+ caching_ctl = container_of(work, struct btrfs_caching_control, work);
+ block_group = caching_ctl->block_group;
+ fs_info = block_group->fs_info;
+
+ mutex_lock(&caching_ctl->mutex);
+ down_read(&fs_info->commit_root_sem);
+
+ if (btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE))
+ ret = load_free_space_tree(caching_ctl);
+ else
+ ret = load_extent_tree_free(caching_ctl);
+
+ spin_lock(&block_group->lock);
+ block_group->caching_ctl = NULL;
+ block_group->cached = ret ? BTRFS_CACHE_ERROR : BTRFS_CACHE_FINISHED;
+ spin_unlock(&block_group->lock);
+
+#ifdef CONFIG_BTRFS_DEBUG
+ if (btrfs_should_fragment_free_space(block_group)) {
+ u64 bytes_used;
+
+ spin_lock(&block_group->space_info->lock);
+ spin_lock(&block_group->lock);
+ bytes_used = block_group->key.offset -
+ btrfs_block_group_used(&block_group->item);
+ block_group->space_info->bytes_used += bytes_used >> 1;
+ spin_unlock(&block_group->lock);
+ spin_unlock(&block_group->space_info->lock);
+ fragment_free_space(block_group);
+ }
+#endif
+
+ caching_ctl->progress = (u64)-1;
+
+ up_read(&fs_info->commit_root_sem);
+ btrfs_free_excluded_extents(block_group);
+ mutex_unlock(&caching_ctl->mutex);
+
+ wake_up(&caching_ctl->wait);
+
+ btrfs_put_caching_control(caching_ctl);
+ btrfs_put_block_group(block_group);
+}
+
+int btrfs_cache_block_group(struct btrfs_block_group_cache *cache,
+ int load_cache_only)
+{
+ DEFINE_WAIT(wait);
+ struct btrfs_fs_info *fs_info = cache->fs_info;
+ struct btrfs_caching_control *caching_ctl;
+ int ret = 0;
+
+ caching_ctl = kzalloc(sizeof(*caching_ctl), GFP_NOFS);
+ if (!caching_ctl)
+ return -ENOMEM;
+
+ INIT_LIST_HEAD(&caching_ctl->list);
+ mutex_init(&caching_ctl->mutex);
+ init_waitqueue_head(&caching_ctl->wait);
+ caching_ctl->block_group = cache;
+ caching_ctl->progress = cache->key.objectid;
+ refcount_set(&caching_ctl->count, 1);
+ btrfs_init_work(&caching_ctl->work, btrfs_cache_helper,
+ caching_thread, NULL, NULL);
+
+ spin_lock(&cache->lock);
+ /*
+ * This should be a rare occasion, but this could happen I think in the
+ * case where one thread starts to load the space cache info, and then
+ * some other thread starts a transaction commit which tries to do an
+ * allocation while the other thread is still loading the space cache
+ * info. The previous loop should have kept us from choosing this block
+ * group, but if we've moved to the state where we will wait on caching
+ * block groups we need to first check if we're doing a fast load here,
+ * so we can wait for it to finish, otherwise we could end up allocating
+ * from a block group who's cache gets evicted for one reason or
+ * another.
+ */
+ while (cache->cached == BTRFS_CACHE_FAST) {
+ struct btrfs_caching_control *ctl;
+
+ ctl = cache->caching_ctl;
+ refcount_inc(&ctl->count);
+ prepare_to_wait(&ctl->wait, &wait, TASK_UNINTERRUPTIBLE);
+ spin_unlock(&cache->lock);
+
+ schedule();
+
+ finish_wait(&ctl->wait, &wait);
+ btrfs_put_caching_control(ctl);
+ spin_lock(&cache->lock);
+ }
+
+ if (cache->cached != BTRFS_CACHE_NO) {
+ spin_unlock(&cache->lock);
+ kfree(caching_ctl);
+ return 0;
+ }
+ WARN_ON(cache->caching_ctl);
+ cache->caching_ctl = caching_ctl;
+ cache->cached = BTRFS_CACHE_FAST;
+ spin_unlock(&cache->lock);
+
+ if (btrfs_test_opt(fs_info, SPACE_CACHE)) {
+ mutex_lock(&caching_ctl->mutex);
+ ret = load_free_space_cache(cache);
+
+ spin_lock(&cache->lock);
+ if (ret == 1) {
+ cache->caching_ctl = NULL;
+ cache->cached = BTRFS_CACHE_FINISHED;
+ cache->last_byte_to_unpin = (u64)-1;
+ caching_ctl->progress = (u64)-1;
+ } else {
+ if (load_cache_only) {
+ cache->caching_ctl = NULL;
+ cache->cached = BTRFS_CACHE_NO;
+ } else {
+ cache->cached = BTRFS_CACHE_STARTED;
+ cache->has_caching_ctl = 1;
+ }
+ }
+ spin_unlock(&cache->lock);
+#ifdef CONFIG_BTRFS_DEBUG
+ if (ret == 1 &&
+ btrfs_should_fragment_free_space(cache)) {
+ u64 bytes_used;
+
+ spin_lock(&cache->space_info->lock);
+ spin_lock(&cache->lock);
+ bytes_used = cache->key.offset -
+ btrfs_block_group_used(&cache->item);
+ cache->space_info->bytes_used += bytes_used >> 1;
+ spin_unlock(&cache->lock);
+ spin_unlock(&cache->space_info->lock);
+ fragment_free_space(cache);
+ }
+#endif
+ mutex_unlock(&caching_ctl->mutex);
+
+ wake_up(&caching_ctl->wait);
+ if (ret == 1) {
+ btrfs_put_caching_control(caching_ctl);
+ btrfs_free_excluded_extents(cache);
+ return 0;
+ }
+ } else {
+ /*
+ * We're either using the free space tree or no caching at all.
+ * Set cached to the appropriate value and wakeup any waiters.
+ */
+ spin_lock(&cache->lock);
+ if (load_cache_only) {
+ cache->caching_ctl = NULL;
+ cache->cached = BTRFS_CACHE_NO;
+ } else {
+ cache->cached = BTRFS_CACHE_STARTED;
+ cache->has_caching_ctl = 1;
+ }
+ spin_unlock(&cache->lock);
+ wake_up(&caching_ctl->wait);
+ }
+
+ if (load_cache_only) {
+ btrfs_put_caching_control(caching_ctl);
+ return 0;
+ }
+
+ down_write(&fs_info->commit_root_sem);
+ refcount_inc(&caching_ctl->count);
+ list_add_tail(&caching_ctl->list, &fs_info->caching_block_groups);
+ up_write(&fs_info->commit_root_sem);
+
+ btrfs_get_block_group(cache);
+
+ btrfs_queue_work(fs_info->caching_workers, &caching_ctl->work);
+
+ return ret;
+}
+
+static void clear_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
+{
+ u64 extra_flags = chunk_to_extended(flags) &
+ BTRFS_EXTENDED_PROFILE_MASK;
+
+ write_seqlock(&fs_info->profiles_lock);
+ if (flags & BTRFS_BLOCK_GROUP_DATA)
+ fs_info->avail_data_alloc_bits &= ~extra_flags;
+ if (flags & BTRFS_BLOCK_GROUP_METADATA)
+ fs_info->avail_metadata_alloc_bits &= ~extra_flags;
+ if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
+ fs_info->avail_system_alloc_bits &= ~extra_flags;
+ write_sequnlock(&fs_info->profiles_lock);
+}
+
+/*
+ * Clear incompat bits for the following feature(s):
+ *
+ * - RAID56 - in case there's neither RAID5 nor RAID6 profile block group
+ * in the whole filesystem
+ */
+static void clear_incompat_bg_bits(struct btrfs_fs_info *fs_info, u64 flags)
+{
+ if (flags & BTRFS_BLOCK_GROUP_RAID56_MASK) {
+ struct list_head *head = &fs_info->space_info;
+ struct btrfs_space_info *sinfo;
+
+ list_for_each_entry_rcu(sinfo, head, list) {
+ bool found = false;
+
+ down_read(&sinfo->groups_sem);
+ if (!list_empty(&sinfo->block_groups[BTRFS_RAID_RAID5]))
+ found = true;
+ if (!list_empty(&sinfo->block_groups[BTRFS_RAID_RAID6]))
+ found = true;
+ up_read(&sinfo->groups_sem);
+
+ if (found)
+ return;
+ }
+ btrfs_clear_fs_incompat(fs_info, RAID56);
+ }
+}
+
+int btrfs_remove_block_group(struct btrfs_trans_handle *trans,
+ u64 group_start, struct extent_map *em)
+{
+ struct btrfs_fs_info *fs_info = trans->fs_info;
+ struct btrfs_root *root = fs_info->extent_root;
+ struct btrfs_path *path;
+ struct btrfs_block_group_cache *block_group;
+ struct btrfs_free_cluster *cluster;
+ struct btrfs_root *tree_root = fs_info->tree_root;
+ struct btrfs_key key;
+ struct inode *inode;
+ struct kobject *kobj = NULL;
+ int ret;
+ int index;
+ int factor;
+ struct btrfs_caching_control *caching_ctl = NULL;
+ bool remove_em;
+ bool remove_rsv = false;
+
+ block_group = btrfs_lookup_block_group(fs_info, group_start);
+ BUG_ON(!block_group);
+ BUG_ON(!block_group->ro);
+
+ trace_btrfs_remove_block_group(block_group);
+ /*
+ * Free the reserved super bytes from this block group before
+ * remove it.
+ */
+ btrfs_free_excluded_extents(block_group);
+ btrfs_free_ref_tree_range(fs_info, block_group->key.objectid,
+ block_group->key.offset);
+
+ memcpy(&key, &block_group->key, sizeof(key));
+ index = btrfs_bg_flags_to_raid_index(block_group->flags);
+ factor = btrfs_bg_type_to_factor(block_group->flags);
+
+ /* make sure this block group isn't part of an allocation cluster */
+ cluster = &fs_info->data_alloc_cluster;
+ spin_lock(&cluster->refill_lock);
+ btrfs_return_cluster_to_free_space(block_group, cluster);
+ spin_unlock(&cluster->refill_lock);
+
+ /*
+ * make sure this block group isn't part of a metadata
+ * allocation cluster
+ */
+ cluster = &fs_info->meta_alloc_cluster;
+ spin_lock(&cluster->refill_lock);
+ btrfs_return_cluster_to_free_space(block_group, cluster);
+ spin_unlock(&cluster->refill_lock);
+
+ path = btrfs_alloc_path();
+ if (!path) {
+ ret = -ENOMEM;
+ goto out;
+ }
+
+ /*
+ * get the inode first so any iput calls done for the io_list
+ * aren't the final iput (no unlinks allowed now)
+ */
+ inode = lookup_free_space_inode(block_group, path);
+
+ mutex_lock(&trans->transaction->cache_write_mutex);
+ /*
+ * Make sure our free space cache IO is done before removing the
+ * free space inode
+ */
+ spin_lock(&trans->transaction->dirty_bgs_lock);
+ if (!list_empty(&block_group->io_list)) {
+ list_del_init(&block_group->io_list);
+
+ WARN_ON(!IS_ERR(inode) && inode != block_group->io_ctl.inode);
+
+ spin_unlock(&trans->transaction->dirty_bgs_lock);
+ btrfs_wait_cache_io(trans, block_group, path);
+ btrfs_put_block_group(block_group);
+ spin_lock(&trans->transaction->dirty_bgs_lock);
+ }
+
+ if (!list_empty(&block_group->dirty_list)) {
+ list_del_init(&block_group->dirty_list);
+ remove_rsv = true;
+ btrfs_put_block_group(block_group);
+ }
+ spin_unlock(&trans->transaction->dirty_bgs_lock);
+ mutex_unlock(&trans->transaction->cache_write_mutex);
+
+ if (!IS_ERR(inode)) {
+ ret = btrfs_orphan_add(trans, BTRFS_I(inode));
+ if (ret) {
+ btrfs_add_delayed_iput(inode);
+ goto out;
+ }
+ clear_nlink(inode);
+ /* One for the block groups ref */
+ spin_lock(&block_group->lock);
+ if (block_group->iref) {
+ block_group->iref = 0;
+ block_group->inode = NULL;
+ spin_unlock(&block_group->lock);
+ iput(inode);
+ } else {
+ spin_unlock(&block_group->lock);
+ }
+ /* One for our lookup ref */
+ btrfs_add_delayed_iput(inode);
+ }
+
+ key.objectid = BTRFS_FREE_SPACE_OBJECTID;
+ key.offset = block_group->key.objectid;
+ key.type = 0;
+
+ ret = btrfs_search_slot(trans, tree_root, &key, path, -1, 1);
+ if (ret < 0)
+ goto out;
+ if (ret > 0)
+ btrfs_release_path(path);
+ if (ret == 0) {
+ ret = btrfs_del_item(trans, tree_root, path);
+ if (ret)
+ goto out;
+ btrfs_release_path(path);
+ }
+
+ spin_lock(&fs_info->block_group_cache_lock);
+ rb_erase(&block_group->cache_node,
+ &fs_info->block_group_cache_tree);
+ RB_CLEAR_NODE(&block_group->cache_node);
+
+ if (fs_info->first_logical_byte == block_group->key.objectid)
+ fs_info->first_logical_byte = (u64)-1;
+ spin_unlock(&fs_info->block_group_cache_lock);
+
+ down_write(&block_group->space_info->groups_sem);
+ /*
+ * we must use list_del_init so people can check to see if they
+ * are still on the list after taking the semaphore
+ */
+ list_del_init(&block_group->list);
+ if (list_empty(&block_group->space_info->block_groups[index])) {
+ kobj = block_group->space_info->block_group_kobjs[index];
+ block_group->space_info->block_group_kobjs[index] = NULL;
+ clear_avail_alloc_bits(fs_info, block_group->flags);
+ }
+ up_write(&block_group->space_info->groups_sem);
+ clear_incompat_bg_bits(fs_info, block_group->flags);
+ if (kobj) {
+ kobject_del(kobj);
+ kobject_put(kobj);
+ }
+
+ if (block_group->has_caching_ctl)
+ caching_ctl = btrfs_get_caching_control(block_group);
+ if (block_group->cached == BTRFS_CACHE_STARTED)
+ btrfs_wait_block_group_cache_done(block_group);
+ if (block_group->has_caching_ctl) {
+ down_write(&fs_info->commit_root_sem);
+ if (!caching_ctl) {
+ struct btrfs_caching_control *ctl;
+
+ list_for_each_entry(ctl,
+ &fs_info->caching_block_groups, list)
+ if (ctl->block_group == block_group) {
+ caching_ctl = ctl;
+ refcount_inc(&caching_ctl->count);
+ break;
+ }
+ }
+ if (caching_ctl)
+ list_del_init(&caching_ctl->list);
+ up_write(&fs_info->commit_root_sem);
+ if (caching_ctl) {
+ /* Once for the caching bgs list and once for us. */
+ btrfs_put_caching_control(caching_ctl);
+ btrfs_put_caching_control(caching_ctl);
+ }
+ }
+
+ spin_lock(&trans->transaction->dirty_bgs_lock);
+ WARN_ON(!list_empty(&block_group->dirty_list));
+ WARN_ON(!list_empty(&block_group->io_list));
+ spin_unlock(&trans->transaction->dirty_bgs_lock);
+
+ btrfs_remove_free_space_cache(block_group);
+
+ spin_lock(&block_group->space_info->lock);
+ list_del_init(&block_group->ro_list);
+
+ if (btrfs_test_opt(fs_info, ENOSPC_DEBUG)) {
+ WARN_ON(block_group->space_info->total_bytes
+ < block_group->key.offset);
+ WARN_ON(block_group->space_info->bytes_readonly
+ < block_group->key.offset);
+ WARN_ON(block_group->space_info->disk_total
+ < block_group->key.offset * factor);
+ }
+ block_group->space_info->total_bytes -= block_group->key.offset;
+ block_group->space_info->bytes_readonly -= block_group->key.offset;
+ block_group->space_info->disk_total -= block_group->key.offset * factor;
+
+ spin_unlock(&block_group->space_info->lock);
+
+ memcpy(&key, &block_group->key, sizeof(key));
+
+ mutex_lock(&fs_info->chunk_mutex);
+ spin_lock(&block_group->lock);
+ block_group->removed = 1;
+ /*
+ * At this point trimming can't start on this block group, because we
+ * removed the block group from the tree fs_info->block_group_cache_tree
+ * so no one can't find it anymore and even if someone already got this
+ * block group before we removed it from the rbtree, they have already
+ * incremented block_group->trimming - if they didn't, they won't find
+ * any free space entries because we already removed them all when we
+ * called btrfs_remove_free_space_cache().
+ *
+ * And we must not remove the extent map from the fs_info->mapping_tree
+ * to prevent the same logical address range and physical device space
+ * ranges from being reused for a new block group. This is because our
+ * fs trim operation (btrfs_trim_fs() / btrfs_ioctl_fitrim()) is
+ * completely transactionless, so while it is trimming a range the
+ * currently running transaction might finish and a new one start,
+ * allowing for new block groups to be created that can reuse the same
+ * physical device locations unless we take this special care.
+ *
+ * There may also be an implicit trim operation if the file system
+ * is mounted with -odiscard. The same protections must remain
+ * in place until the extents have been discarded completely when
+ * the transaction commit has completed.
+ */
+ remove_em = (atomic_read(&block_group->trimming) == 0);
+ spin_unlock(&block_group->lock);
+
+ mutex_unlock(&fs_info->chunk_mutex);
+
+ ret = remove_block_group_free_space(trans, block_group);
+ if (ret)
+ goto out;
+
+ btrfs_put_block_group(block_group);
+ btrfs_put_block_group(block_group);
+
+ ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
+ if (ret > 0)
+ ret = -EIO;
+ if (ret < 0)
+ goto out;
+
+ ret = btrfs_del_item(trans, root, path);
+ if (ret)
+ goto out;
+
+ if (remove_em) {
+ struct extent_map_tree *em_tree;
+
+ em_tree = &fs_info->mapping_tree;
+ write_lock(&em_tree->lock);
+ remove_extent_mapping(em_tree, em);
+ write_unlock(&em_tree->lock);
+ /* once for the tree */
+ free_extent_map(em);
+ }
+out:
+ if (remove_rsv)
+ btrfs_delayed_refs_rsv_release(fs_info, 1);
+ btrfs_free_path(path);
+ return ret;
+}
+
+struct btrfs_trans_handle *btrfs_start_trans_remove_block_group(
+ struct btrfs_fs_info *fs_info, const u64 chunk_offset)
+{
+ struct extent_map_tree *em_tree = &fs_info->mapping_tree;
+ struct extent_map *em;
+ struct map_lookup *map;
+ unsigned int num_items;
+
+ read_lock(&em_tree->lock);
+ em = lookup_extent_mapping(em_tree, chunk_offset, 1);
+ read_unlock(&em_tree->lock);
+ ASSERT(em && em->start == chunk_offset);
+
+ /*
+ * We need to reserve 3 + N units from the metadata space info in order
+ * to remove a block group (done at btrfs_remove_chunk() and at
+ * btrfs_remove_block_group()), which are used for:
+ *
+ * 1 unit for adding the free space inode's orphan (located in the tree
+ * of tree roots).
+ * 1 unit for deleting the block group item (located in the extent
+ * tree).
+ * 1 unit for deleting the free space item (located in tree of tree
+ * roots).
+ * N units for deleting N device extent items corresponding to each
+ * stripe (located in the device tree).
+ *
+ * In order to remove a block group we also need to reserve units in the
+ * system space info in order to update the chunk tree (update one or
+ * more device items and remove one chunk item), but this is done at
+ * btrfs_remove_chunk() through a call to check_system_chunk().
+ */
+ map = em->map_lookup;
+ num_items = 3 + map->num_stripes;
+ free_extent_map(em);
+
+ return btrfs_start_transaction_fallback_global_rsv(fs_info->extent_root,
+ num_items, 1);
+}
+
+/*
+ * Mark block group @cache read-only, so later write won't happen to block
+ * group @cache.
+ *
+ * If @force is not set, this function will only mark the block group readonly
+ * if we have enough free space (1M) in other metadata/system block groups.
+ * If @force is not set, this function will mark the block group readonly
+ * without checking free space.
+ *
+ * NOTE: This function doesn't care if other block groups can contain all the
+ * data in this block group. That check should be done by relocation routine,
+ * not this function.
+ */
+static int inc_block_group_ro(struct btrfs_block_group_cache *cache, int force)
+{
+ struct btrfs_space_info *sinfo = cache->space_info;
+ u64 num_bytes;
+ u64 sinfo_used;
+ u64 min_allocable_bytes;
+ int ret = -ENOSPC;
+
+ /*
+ * We need some metadata space and system metadata space for
+ * allocating chunks in some corner cases until we force to set
+ * it to be readonly.
+ */
+ if ((sinfo->flags &
+ (BTRFS_BLOCK_GROUP_SYSTEM | BTRFS_BLOCK_GROUP_METADATA)) &&
+ !force)
+ min_allocable_bytes = SZ_1M;
+ else
+ min_allocable_bytes = 0;
+
+ spin_lock(&sinfo->lock);
+ spin_lock(&cache->lock);
+
+ if (cache->ro) {
+ cache->ro++;
+ ret = 0;
+ goto out;
+ }
+
+ num_bytes = cache->key.offset - cache->reserved - cache->pinned -
+ cache->bytes_super - btrfs_block_group_used(&cache->item);
+ 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 (if min_allocable_bytes is not 0).
+ */
+ if (sinfo_used + num_bytes + min_allocable_bytes <=
+ sinfo->total_bytes) {
+ sinfo->bytes_readonly += num_bytes;
+ cache->ro++;
+ list_add_tail(&cache->ro_list, &sinfo->ro_bgs);
+ ret = 0;
+ }
+out:
+ spin_unlock(&cache->lock);
+ spin_unlock(&sinfo->lock);
+ if (ret == -ENOSPC && btrfs_test_opt(cache->fs_info, ENOSPC_DEBUG)) {
+ btrfs_info(cache->fs_info,
+ "unable to make block group %llu ro",
+ cache->key.objectid);
+ btrfs_info(cache->fs_info,
+ "sinfo_used=%llu bg_num_bytes=%llu min_allocable=%llu",
+ sinfo_used, num_bytes, min_allocable_bytes);
+ btrfs_dump_space_info(cache->fs_info, cache->space_info, 0, 0);
+ }
+ return ret;
+}
+
+/*
+ * Process the unused_bgs list and remove any that don't have any allocated
+ * space inside of them.
+ */
+void btrfs_delete_unused_bgs(struct btrfs_fs_info *fs_info)
+{
+ struct btrfs_block_group_cache *block_group;
+ struct btrfs_space_info *space_info;
+ struct btrfs_trans_handle *trans;
+ int ret = 0;
+
+ if (!test_bit(BTRFS_FS_OPEN, &fs_info->flags))
+ return;
+
+ spin_lock(&fs_info->unused_bgs_lock);
+ while (!list_empty(&fs_info->unused_bgs)) {
+ u64 start, end;
+ int trimming;
+
+ block_group = list_first_entry(&fs_info->unused_bgs,
+ struct btrfs_block_group_cache,
+ bg_list);
+ list_del_init(&block_group->bg_list);
+
+ space_info = block_group->space_info;
+
+ if (ret || btrfs_mixed_space_info(space_info)) {
+ btrfs_put_block_group(block_group);
+ continue;
+ }
+ spin_unlock(&fs_info->unused_bgs_lock);
+
+ mutex_lock(&fs_info->delete_unused_bgs_mutex);
+
+ /* Don't want to race with allocators so take the groups_sem */
+ down_write(&space_info->groups_sem);
+ spin_lock(&block_group->lock);
+ if (block_group->reserved || block_group->pinned ||
+ btrfs_block_group_used(&block_group->item) ||
+ block_group->ro ||
+ list_is_singular(&block_group->list)) {
+ /*
+ * We want to bail if we made new allocations or have
+ * outstanding allocations in this block group. We do
+ * the ro check in case balance is currently acting on
+ * this block group.
+ */
+ trace_btrfs_skip_unused_block_group(block_group);
+ spin_unlock(&block_group->lock);
+ up_write(&space_info->groups_sem);
+ goto next;
+ }
+ spin_unlock(&block_group->lock);
+
+ /* We don't want to force the issue, only flip if it's ok. */
+ ret = inc_block_group_ro(block_group, 0);
+ up_write(&space_info->groups_sem);
+ if (ret < 0) {
+ ret = 0;
+ goto next;
+ }
+
+ /*
+ * Want to do this before we do anything else so we can recover
+ * properly if we fail to join the transaction.
+ */
+ trans = btrfs_start_trans_remove_block_group(fs_info,
+ block_group->key.objectid);
+ if (IS_ERR(trans)) {
+ btrfs_dec_block_group_ro(block_group);
+ ret = PTR_ERR(trans);
+ goto next;
+ }
+
+ /*
+ * We could have pending pinned extents for this block group,
+ * just delete them, we don't care about them anymore.
+ */
+ start = block_group->key.objectid;
+ end = start + block_group->key.offset - 1;
+ /*
+ * Hold the unused_bg_unpin_mutex lock to avoid racing with
+ * btrfs_finish_extent_commit(). If we are at transaction N,
+ * another task might be running finish_extent_commit() for the
+ * previous transaction N - 1, and have seen a range belonging
+ * to the block group in freed_extents[] before we were able to
+ * clear the whole block group range from freed_extents[]. This
+ * means that task can lookup for the block group after we
+ * unpinned it from freed_extents[] and removed it, leading to
+ * a BUG_ON() at btrfs_unpin_extent_range().
+ */
+ mutex_lock(&fs_info->unused_bg_unpin_mutex);
+ ret = clear_extent_bits(&fs_info->freed_extents[0], start, end,
+ EXTENT_DIRTY);
+ if (ret) {
+ mutex_unlock(&fs_info->unused_bg_unpin_mutex);
+ btrfs_dec_block_group_ro(block_group);
+ goto end_trans;
+ }
+ ret = clear_extent_bits(&fs_info->freed_extents[1], start, end,
+ EXTENT_DIRTY);
+ if (ret) {
+ mutex_unlock(&fs_info->unused_bg_unpin_mutex);
+ btrfs_dec_block_group_ro(block_group);
+ goto end_trans;
+ }
+ mutex_unlock(&fs_info->unused_bg_unpin_mutex);
+
+ /* Reset pinned so btrfs_put_block_group doesn't complain */
+ spin_lock(&space_info->lock);
+ spin_lock(&block_group->lock);
+
+ btrfs_space_info_update_bytes_pinned(fs_info, space_info,
+ -block_group->pinned);
+ space_info->bytes_readonly += block_group->pinned;
+ percpu_counter_add_batch(&space_info->total_bytes_pinned,
+ -block_group->pinned,
+ BTRFS_TOTAL_BYTES_PINNED_BATCH);
+ block_group->pinned = 0;
+
+ spin_unlock(&block_group->lock);
+ spin_unlock(&space_info->lock);
+
+ /* DISCARD can flip during remount */
+ trimming = btrfs_test_opt(fs_info, DISCARD);
+
+ /* Implicit trim during transaction commit. */
+ if (trimming)
+ btrfs_get_block_group_trimming(block_group);
+
+ /*
+ * Btrfs_remove_chunk will abort the transaction if things go
+ * horribly wrong.
+ */
+ ret = btrfs_remove_chunk(trans, block_group->key.objectid);
+
+ if (ret) {
+ if (trimming)
+ btrfs_put_block_group_trimming(block_group);
+ goto end_trans;
+ }
+
+ /*
+ * If we're not mounted with -odiscard, we can just forget
+ * about this block group. Otherwise we'll need to wait
+ * until transaction commit to do the actual discard.
+ */
+ if (trimming) {
+ spin_lock(&fs_info->unused_bgs_lock);
+ /*
+ * A concurrent scrub might have added us to the list
+ * fs_info->unused_bgs, so use a list_move operation
+ * to add the block group to the deleted_bgs list.
+ */
+ list_move(&block_group->bg_list,
+ &trans->transaction->deleted_bgs);
+ spin_unlock(&fs_info->unused_bgs_lock);
+ btrfs_get_block_group(block_group);
+ }
+end_trans:
+ btrfs_end_transaction(trans);
+next:
+ mutex_unlock(&fs_info->delete_unused_bgs_mutex);
+ btrfs_put_block_group(block_group);
+ spin_lock(&fs_info->unused_bgs_lock);
+ }
+ spin_unlock(&fs_info->unused_bgs_lock);
+}
+
+void btrfs_mark_bg_unused(struct btrfs_block_group_cache *bg)
+{
+ struct btrfs_fs_info *fs_info = bg->fs_info;
+
+ spin_lock(&fs_info->unused_bgs_lock);
+ if (list_empty(&bg->bg_list)) {
+ btrfs_get_block_group(bg);
+ trace_btrfs_add_unused_block_group(bg);
+ list_add_tail(&bg->bg_list, &fs_info->unused_bgs);
+ }
+ spin_unlock(&fs_info->unused_bgs_lock);
+}
+
+static int find_first_block_group(struct btrfs_fs_info *fs_info,
+ struct btrfs_path *path,
+ struct btrfs_key *key)
+{
+ struct btrfs_root *root = fs_info->extent_root;
+ int ret = 0;
+ struct btrfs_key found_key;
+ struct extent_buffer *leaf;
+ struct btrfs_block_group_item bg;
+ u64 flags;
+ int slot;
+
+ ret = btrfs_search_slot(NULL, root, key, path, 0, 0);
+ if (ret < 0)
+ goto out;
+
+ while (1) {
+ slot = path->slots[0];
+ leaf = path->nodes[0];
+ if (slot >= btrfs_header_nritems(leaf)) {
+ ret = btrfs_next_leaf(root, path);
+ if (ret == 0)
+ continue;
+ if (ret < 0)
+ goto out;
+ break;
+ }
+ btrfs_item_key_to_cpu(leaf, &found_key, slot);
+
+ if (found_key.objectid >= key->objectid &&
+ found_key.type == BTRFS_BLOCK_GROUP_ITEM_KEY) {
+ struct extent_map_tree *em_tree;
+ struct extent_map *em;
+
+ em_tree = &root->fs_info->mapping_tree;
+ read_lock(&em_tree->lock);
+ em = lookup_extent_mapping(em_tree, found_key.objectid,
+ found_key.offset);
+ read_unlock(&em_tree->lock);
+ if (!em) {
+ btrfs_err(fs_info,
+ "logical %llu len %llu found bg but no related chunk",
+ found_key.objectid, found_key.offset);
+ ret = -ENOENT;
+ } else if (em->start != found_key.objectid ||
+ em->len != found_key.offset) {
+ btrfs_err(fs_info,
+ "block group %llu len %llu mismatch with chunk %llu len %llu",
+ found_key.objectid, found_key.offset,
+ em->start, em->len);
+ ret = -EUCLEAN;
+ } else {
+ read_extent_buffer(leaf, &bg,
+ btrfs_item_ptr_offset(leaf, slot),
+ sizeof(bg));
+ flags = btrfs_block_group_flags(&bg) &
+ BTRFS_BLOCK_GROUP_TYPE_MASK;
+
+ if (flags != (em->map_lookup->type &
+ BTRFS_BLOCK_GROUP_TYPE_MASK)) {
+ btrfs_err(fs_info,
+"block group %llu len %llu type flags 0x%llx mismatch with chunk type flags 0x%llx",
+ found_key.objectid,
+ found_key.offset, flags,
+ (BTRFS_BLOCK_GROUP_TYPE_MASK &
+ em->map_lookup->type));
+ ret = -EUCLEAN;
+ } else {
+ ret = 0;
+ }
+ }
+ free_extent_map(em);
+ goto out;
+ }
+ path->slots[0]++;
+ }
+out:
+ return ret;
+}
+
+static void set_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
+{
+ u64 extra_flags = chunk_to_extended(flags) &
+ BTRFS_EXTENDED_PROFILE_MASK;
+
+ write_seqlock(&fs_info->profiles_lock);
+ if (flags & BTRFS_BLOCK_GROUP_DATA)
+ fs_info->avail_data_alloc_bits |= extra_flags;
+ if (flags & BTRFS_BLOCK_GROUP_METADATA)
+ fs_info->avail_metadata_alloc_bits |= extra_flags;
+ if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
+ fs_info->avail_system_alloc_bits |= extra_flags;
+ write_sequnlock(&fs_info->profiles_lock);
+}
+
+static int exclude_super_stripes(struct btrfs_block_group_cache *cache)
+{
+ struct btrfs_fs_info *fs_info = cache->fs_info;
+ u64 bytenr;
+ u64 *logical;
+ int stripe_len;
+ int i, nr, ret;
+
+ if (cache->key.objectid < BTRFS_SUPER_INFO_OFFSET) {
+ stripe_len = BTRFS_SUPER_INFO_OFFSET - cache->key.objectid;
+ cache->bytes_super += stripe_len;
+ ret = btrfs_add_excluded_extent(fs_info, cache->key.objectid,
+ stripe_len);
+ if (ret)
+ return ret;
+ }
+
+ for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
+ bytenr = btrfs_sb_offset(i);
+ ret = btrfs_rmap_block(fs_info, cache->key.objectid,
+ bytenr, &logical, &nr, &stripe_len);
+ if (ret)
+ return ret;
+
+ while (nr--) {
+ u64 start, len;
+
+ if (logical[nr] > cache->key.objectid +
+ cache->key.offset)
+ continue;
+
+ if (logical[nr] + stripe_len <= cache->key.objectid)
+ continue;
+
+ start = logical[nr];
+ if (start < cache->key.objectid) {
+ start = cache->key.objectid;
+ len = (logical[nr] + stripe_len) - start;
+ } else {
+ len = min_t(u64, stripe_len,
+ cache->key.objectid +
+ cache->key.offset - start);
+ }
+
+ cache->bytes_super += len;
+ ret = btrfs_add_excluded_extent(fs_info, start, len);
+ if (ret) {
+ kfree(logical);
+ return ret;
+ }
+ }
+
+ kfree(logical);
+ }
+ return 0;
+}
+
+static void link_block_group(struct btrfs_block_group_cache *cache)
+{
+ struct btrfs_space_info *space_info = cache->space_info;
+ int index = btrfs_bg_flags_to_raid_index(cache->flags);
+ bool first = false;
+
+ down_write(&space_info->groups_sem);
+ if (list_empty(&space_info->block_groups[index]))
+ first = true;
+ list_add_tail(&cache->list, &space_info->block_groups[index]);
+ up_write(&space_info->groups_sem);
+
+ if (first)
+ btrfs_sysfs_add_block_group_type(cache);
+}
+
+static struct btrfs_block_group_cache *btrfs_create_block_group_cache(
+ struct btrfs_fs_info *fs_info, u64 start, u64 size)
+{
+ struct btrfs_block_group_cache *cache;
+
+ cache = kzalloc(sizeof(*cache), GFP_NOFS);
+ if (!cache)
+ return NULL;
+
+ cache->free_space_ctl = kzalloc(sizeof(*cache->free_space_ctl),
+ GFP_NOFS);
+ if (!cache->free_space_ctl) {
+ kfree(cache);
+ return NULL;
+ }
+
+ cache->key.objectid = start;
+ cache->key.offset = size;
+ cache->key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
+
+ cache->fs_info = fs_info;
+ cache->full_stripe_len = btrfs_full_stripe_len(fs_info, start);
+ set_free_space_tree_thresholds(cache);
+
+ atomic_set(&cache->count, 1);
+ spin_lock_init(&cache->lock);
+ init_rwsem(&cache->data_rwsem);
+ INIT_LIST_HEAD(&cache->list);
+ INIT_LIST_HEAD(&cache->cluster_list);
+ INIT_LIST_HEAD(&cache->bg_list);
+ INIT_LIST_HEAD(&cache->ro_list);
+ INIT_LIST_HEAD(&cache->dirty_list);
+ INIT_LIST_HEAD(&cache->io_list);
+ btrfs_init_free_space_ctl(cache);
+ atomic_set(&cache->trimming, 0);
+ mutex_init(&cache->free_space_lock);
+ btrfs_init_full_stripe_locks_tree(&cache->full_stripe_locks_root);
+
+ return cache;
+}
+
+/*
+ * Iterate all chunks and verify that each of them has the corresponding block
+ * group
+ */
+static int check_chunk_block_group_mappings(struct btrfs_fs_info *fs_info)
+{
+ struct extent_map_tree *map_tree = &fs_info->mapping_tree;
+ struct extent_map *em;
+ struct btrfs_block_group_cache *bg;
+ u64 start = 0;
+ int ret = 0;
+
+ while (1) {
+ read_lock(&map_tree->lock);
+ /*
+ * lookup_extent_mapping will return the first extent map
+ * intersecting the range, so setting @len to 1 is enough to
+ * get the first chunk.
+ */
+ em = lookup_extent_mapping(map_tree, start, 1);
+ read_unlock(&map_tree->lock);
+ if (!em)
+ break;
+
+ bg = btrfs_lookup_block_group(fs_info, em->start);
+ if (!bg) {
+ btrfs_err(fs_info,
+ "chunk start=%llu len=%llu doesn't have corresponding block group",
+ em->start, em->len);
+ ret = -EUCLEAN;
+ free_extent_map(em);
+ break;
+ }
+ if (bg->key.objectid != em->start ||
+ bg->key.offset != em->len ||
+ (bg->flags & BTRFS_BLOCK_GROUP_TYPE_MASK) !=
+ (em->map_lookup->type & BTRFS_BLOCK_GROUP_TYPE_MASK)) {
+ btrfs_err(fs_info,
+"chunk start=%llu len=%llu flags=0x%llx doesn't match block group start=%llu len=%llu flags=0x%llx",
+ em->start, em->len,
+ em->map_lookup->type & BTRFS_BLOCK_GROUP_TYPE_MASK,
+ bg->key.objectid, bg->key.offset,
+ bg->flags & BTRFS_BLOCK_GROUP_TYPE_MASK);
+ ret = -EUCLEAN;
+ free_extent_map(em);
+ btrfs_put_block_group(bg);
+ break;
+ }
+ start = em->start + em->len;
+ free_extent_map(em);
+ btrfs_put_block_group(bg);
+ }
+ return ret;
+}
+
+int btrfs_read_block_groups(struct btrfs_fs_info *info)
+{
+ struct btrfs_path *path;
+ int ret;
+ struct btrfs_block_group_cache *cache;
+ struct btrfs_space_info *space_info;
+ struct btrfs_key key;
+ struct btrfs_key found_key;
+ struct extent_buffer *leaf;
+ int need_clear = 0;
+ u64 cache_gen;
+ u64 feature;
+ int mixed;
+
+ feature = btrfs_super_incompat_flags(info->super_copy);
+ mixed = !!(feature & BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS);
+
+ key.objectid = 0;
+ key.offset = 0;
+ key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
+ path = btrfs_alloc_path();
+ if (!path)
+ return -ENOMEM;
+ path->reada = READA_FORWARD;
+
+ cache_gen = btrfs_super_cache_generation(info->super_copy);
+ if (btrfs_test_opt(info, SPACE_CACHE) &&
+ btrfs_super_generation(info->super_copy) != cache_gen)
+ need_clear = 1;
+ if (btrfs_test_opt(info, CLEAR_CACHE))
+ need_clear = 1;
+
+ while (1) {
+ ret = find_first_block_group(info, path, &key);
+ if (ret > 0)
+ break;
+ if (ret != 0)
+ goto error;
+
+ leaf = path->nodes[0];
+ btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
+
+ cache = btrfs_create_block_group_cache(info, found_key.objectid,
+ found_key.offset);
+ if (!cache) {
+ ret = -ENOMEM;
+ goto error;
+ }
+
+ if (need_clear) {
+ /*
+ * When we mount with old space cache, we need to
+ * set BTRFS_DC_CLEAR and set dirty flag.
+ *
+ * a) Setting 'BTRFS_DC_CLEAR' makes sure that we
+ * truncate the old free space cache inode and
+ * setup a new one.
+ * b) Setting 'dirty flag' makes sure that we flush
+ * the new space cache info onto disk.
+ */
+ if (btrfs_test_opt(info, SPACE_CACHE))
+ cache->disk_cache_state = BTRFS_DC_CLEAR;
+ }
+
+ read_extent_buffer(leaf, &cache->item,
+ btrfs_item_ptr_offset(leaf, path->slots[0]),
+ sizeof(cache->item));
+ cache->flags = btrfs_block_group_flags(&cache->item);
+ if (!mixed &&
+ ((cache->flags & BTRFS_BLOCK_GROUP_METADATA) &&
+ (cache->flags & BTRFS_BLOCK_GROUP_DATA))) {
+ btrfs_err(info,
+"bg %llu is a mixed block group but filesystem hasn't enabled mixed block groups",
+ cache->key.objectid);
+ btrfs_put_block_group(cache);
+ ret = -EINVAL;
+ goto error;
+ }
+
+ key.objectid = found_key.objectid + found_key.offset;
+ btrfs_release_path(path);
+
+ /*
+ * We need to exclude the super stripes now so that the space
+ * info has super bytes accounted for, otherwise we'll think
+ * we have more space than we actually do.
+ */
+ ret = exclude_super_stripes(cache);
+ if (ret) {
+ /*
+ * We may have excluded something, so call this just in
+ * case.
+ */
+ btrfs_free_excluded_extents(cache);
+ btrfs_put_block_group(cache);
+ goto error;
+ }
+
+ /*
+ * Check for two cases, either we are full, and therefore
+ * don't need to bother with the caching work since we won't
+ * find any space, or we are empty, and we can just add all
+ * the space in and be done with it. This saves us _a_lot_ of
+ * time, particularly in the full case.
+ */
+ if (found_key.offset == btrfs_block_group_used(&cache->item)) {
+ cache->last_byte_to_unpin = (u64)-1;
+ cache->cached = BTRFS_CACHE_FINISHED;
+ btrfs_free_excluded_extents(cache);
+ } else if (btrfs_block_group_used(&cache->item) == 0) {
+ cache->last_byte_to_unpin = (u64)-1;
+ cache->cached = BTRFS_CACHE_FINISHED;
+ add_new_free_space(cache, found_key.objectid,
+ found_key.objectid +
+ found_key.offset);
+ btrfs_free_excluded_extents(cache);
+ }
+
+ ret = btrfs_add_block_group_cache(info, cache);
+ if (ret) {
+ btrfs_remove_free_space_cache(cache);
+ btrfs_put_block_group(cache);
+ goto error;
+ }
+
+ trace_btrfs_add_block_group(info, cache, 0);
+ btrfs_update_space_info(info, cache->flags, found_key.offset,
+ btrfs_block_group_used(&cache->item),
+ cache->bytes_super, &space_info);
+
+ cache->space_info = space_info;
+
+ link_block_group(cache);
+
+ set_avail_alloc_bits(info, cache->flags);
+ if (btrfs_chunk_readonly(info, cache->key.objectid)) {
+ inc_block_group_ro(cache, 1);
+ } else if (btrfs_block_group_used(&cache->item) == 0) {
+ ASSERT(list_empty(&cache->bg_list));
+ btrfs_mark_bg_unused(cache);
+ }
+ }
+
+ list_for_each_entry_rcu(space_info, &info->space_info, list) {
+ if (!(btrfs_get_alloc_profile(info, space_info->flags) &
+ (BTRFS_BLOCK_GROUP_RAID10 |
+ BTRFS_BLOCK_GROUP_RAID1_MASK |
+ BTRFS_BLOCK_GROUP_RAID56_MASK |
+ BTRFS_BLOCK_GROUP_DUP)))
+ continue;
+ /*
+ * Avoid allocating from un-mirrored block group if there are
+ * mirrored block groups.
+ */
+ list_for_each_entry(cache,
+ &space_info->block_groups[BTRFS_RAID_RAID0],
+ list)
+ inc_block_group_ro(cache, 1);
+ list_for_each_entry(cache,
+ &space_info->block_groups[BTRFS_RAID_SINGLE],
+ list)
+ inc_block_group_ro(cache, 1);
+ }
+
+ btrfs_init_global_block_rsv(info);
+ ret = check_chunk_block_group_mappings(info);
+error:
+ btrfs_free_path(path);
+ return ret;
+}
+
+void btrfs_create_pending_block_groups(struct btrfs_trans_handle *trans)
+{
+ struct btrfs_fs_info *fs_info = trans->fs_info;
+ struct btrfs_block_group_cache *block_group;
+ struct btrfs_root *extent_root = fs_info->extent_root;
+ struct btrfs_block_group_item item;
+ struct btrfs_key key;
+ int ret = 0;
+
+ if (!trans->can_flush_pending_bgs)
+ return;
+
+ while (!list_empty(&trans->new_bgs)) {
+ block_group = list_first_entry(&trans->new_bgs,
+ struct btrfs_block_group_cache,
+ bg_list);
+ if (ret)
+ goto next;
+
+ spin_lock(&block_group->lock);
+ memcpy(&item, &block_group->item, sizeof(item));
+ memcpy(&key, &block_group->key, sizeof(key));
+ spin_unlock(&block_group->lock);
+
+ ret = btrfs_insert_item(trans, extent_root, &key, &item,
+ sizeof(item));
+ if (ret)
+ btrfs_abort_transaction(trans, ret);
+ ret = btrfs_finish_chunk_alloc(trans, key.objectid, key.offset);
+ if (ret)
+ btrfs_abort_transaction(trans, ret);
+ add_block_group_free_space(trans, block_group);
+ /* Already aborted the transaction if it failed. */
+next:
+ btrfs_delayed_refs_rsv_release(fs_info, 1);
+ list_del_init(&block_group->bg_list);
+ }
+ btrfs_trans_release_chunk_metadata(trans);
+}
+
+int btrfs_make_block_group(struct btrfs_trans_handle *trans, u64 bytes_used,
+ u64 type, u64 chunk_offset, u64 size)
+{
+ struct btrfs_fs_info *fs_info = trans->fs_info;
+ struct btrfs_block_group_cache *cache;
+ int ret;
+
+ btrfs_set_log_full_commit(trans);
+
+ cache = btrfs_create_block_group_cache(fs_info, chunk_offset, size);
+ if (!cache)
+ return -ENOMEM;
+
+ btrfs_set_block_group_used(&cache->item, bytes_used);
+ btrfs_set_block_group_chunk_objectid(&cache->item,
+ BTRFS_FIRST_CHUNK_TREE_OBJECTID);
+ btrfs_set_block_group_flags(&cache->item, type);
+
+ cache->flags = type;
+ cache->last_byte_to_unpin = (u64)-1;
+ cache->cached = BTRFS_CACHE_FINISHED;
+ cache->needs_free_space = 1;
+ ret = exclude_super_stripes(cache);
+ if (ret) {
+ /* We may have excluded something, so call this just in case */
+ btrfs_free_excluded_extents(cache);
+ btrfs_put_block_group(cache);
+ return ret;
+ }
+
+ add_new_free_space(cache, chunk_offset, chunk_offset + size);
+
+ btrfs_free_excluded_extents(cache);
+
+#ifdef CONFIG_BTRFS_DEBUG
+ if (btrfs_should_fragment_free_space(cache)) {
+ u64 new_bytes_used = size - bytes_used;
+
+ bytes_used += new_bytes_used >> 1;
+ fragment_free_space(cache);
+ }
+#endif
+ /*
+ * Ensure the corresponding space_info object is created and
+ * assigned to our block group. We want our bg to be added to the rbtree
+ * with its ->space_info set.
+ */
+ cache->space_info = btrfs_find_space_info(fs_info, cache->flags);
+ ASSERT(cache->space_info);
+
+ ret = btrfs_add_block_group_cache(fs_info, cache);
+ if (ret) {
+ btrfs_remove_free_space_cache(cache);
+ btrfs_put_block_group(cache);
+ return ret;
+ }
+
+ /*
+ * Now that our block group has its ->space_info set and is inserted in
+ * the rbtree, update the space info's counters.
+ */
+ trace_btrfs_add_block_group(fs_info, cache, 1);
+ btrfs_update_space_info(fs_info, cache->flags, size, bytes_used,
+ cache->bytes_super, &cache->space_info);
+ btrfs_update_global_block_rsv(fs_info);
+
+ link_block_group(cache);
+
+ list_add_tail(&cache->bg_list, &trans->new_bgs);
+ trans->delayed_ref_updates++;
+ btrfs_update_delayed_refs_rsv(trans);
+
+ set_avail_alloc_bits(fs_info, type);
+ return 0;
+}
+
+static u64 update_block_group_flags(struct btrfs_fs_info *fs_info, u64 flags)
+{
+ u64 num_devices;
+ u64 stripped;
+
+ /*
+ * if restripe for this chunk_type is on pick target profile and
+ * return, otherwise do the usual balance
+ */
+ stripped = get_restripe_target(fs_info, flags);
+ if (stripped)
+ return extended_to_chunk(stripped);
+
+ num_devices = fs_info->fs_devices->rw_devices;
+
+ stripped = BTRFS_BLOCK_GROUP_RAID0 | BTRFS_BLOCK_GROUP_RAID56_MASK |
+ BTRFS_BLOCK_GROUP_RAID1_MASK | BTRFS_BLOCK_GROUP_RAID10;
+
+ if (num_devices == 1) {
+ stripped |= BTRFS_BLOCK_GROUP_DUP;
+ stripped = flags & ~stripped;
+
+ /* turn raid0 into single device chunks */
+ if (flags & BTRFS_BLOCK_GROUP_RAID0)
+ return stripped;
+
+ /* turn mirroring into duplication */
+ if (flags & (BTRFS_BLOCK_GROUP_RAID1_MASK |
+ BTRFS_BLOCK_GROUP_RAID10))
+ return stripped | BTRFS_BLOCK_GROUP_DUP;
+ } else {
+ /* they already had raid on here, just return */
+ if (flags & stripped)
+ return flags;
+
+ stripped |= BTRFS_BLOCK_GROUP_DUP;
+ stripped = flags & ~stripped;
+
+ /* switch duplicated blocks with raid1 */
+ if (flags & BTRFS_BLOCK_GROUP_DUP)
+ return stripped | BTRFS_BLOCK_GROUP_RAID1;
+
+ /* this is drive concat, leave it alone */
+ }
+
+ return flags;
+}
+
+int btrfs_inc_block_group_ro(struct btrfs_block_group_cache *cache)
+
+{
+ struct btrfs_fs_info *fs_info = cache->fs_info;
+ struct btrfs_trans_handle *trans;
+ u64 alloc_flags;
+ int ret;
+
+again:
+ trans = btrfs_join_transaction(fs_info->extent_root);
+ if (IS_ERR(trans))
+ return PTR_ERR(trans);
+
+ /*
+ * we're not allowed to set block groups readonly after the dirty
+ * block groups cache has started writing. If it already started,
+ * back off and let this transaction commit
+ */
+ mutex_lock(&fs_info->ro_block_group_mutex);
+ if (test_bit(BTRFS_TRANS_DIRTY_BG_RUN, &trans->transaction->flags)) {
+ u64 transid = trans->transid;
+
+ mutex_unlock(&fs_info->ro_block_group_mutex);
+ btrfs_end_transaction(trans);
+
+ ret = btrfs_wait_for_commit(fs_info, transid);
+ if (ret)
+ return ret;
+ goto again;
+ }
+
+ /*
+ * if we are changing raid levels, try to allocate a corresponding
+ * block group with the new raid level.
+ */
+ alloc_flags = update_block_group_flags(fs_info, cache->flags);
+ if (alloc_flags != cache->flags) {
+ ret = btrfs_chunk_alloc(trans, alloc_flags, CHUNK_ALLOC_FORCE);
+ /*
+ * ENOSPC is allowed here, we may have enough space
+ * already allocated at the new raid level to
+ * carry on
+ */
+ if (ret == -ENOSPC)
+ ret = 0;
+ if (ret < 0)
+ goto out;
+ }
+
+ ret = inc_block_group_ro(cache, 0);
+ if (!ret)
+ goto out;
+ alloc_flags = btrfs_get_alloc_profile(fs_info, cache->space_info->flags);
+ ret = btrfs_chunk_alloc(trans, alloc_flags, CHUNK_ALLOC_FORCE);
+ if (ret < 0)
+ goto out;
+ ret = inc_block_group_ro(cache, 0);
+out:
+ if (cache->flags & BTRFS_BLOCK_GROUP_SYSTEM) {
+ alloc_flags = update_block_group_flags(fs_info, cache->flags);
+ mutex_lock(&fs_info->chunk_mutex);
+ check_system_chunk(trans, alloc_flags);
+ mutex_unlock(&fs_info->chunk_mutex);
+ }
+ mutex_unlock(&fs_info->ro_block_group_mutex);
+
+ btrfs_end_transaction(trans);
+ return ret;
+}
+
+void btrfs_dec_block_group_ro(struct btrfs_block_group_cache *cache)
+{
+ struct btrfs_space_info *sinfo = cache->space_info;
+ u64 num_bytes;
+
+ BUG_ON(!cache->ro);
+
+ spin_lock(&sinfo->lock);
+ spin_lock(&cache->lock);
+ if (!--cache->ro) {
+ num_bytes = cache->key.offset - cache->reserved -
+ cache->pinned - cache->bytes_super -
+ btrfs_block_group_used(&cache->item);
+ sinfo->bytes_readonly -= num_bytes;
+ list_del_init(&cache->ro_list);
+ }
+ spin_unlock(&cache->lock);
+ spin_unlock(&sinfo->lock);
+}
+
+static int write_one_cache_group(struct btrfs_trans_handle *trans,
+ struct btrfs_path *path,
+ struct btrfs_block_group_cache *cache)
+{
+ struct btrfs_fs_info *fs_info = trans->fs_info;
+ int ret;
+ struct btrfs_root *extent_root = fs_info->extent_root;
+ unsigned long bi;
+ struct extent_buffer *leaf;
+
+ ret = btrfs_search_slot(trans, extent_root, &cache->key, path, 0, 1);
+ if (ret) {
+ if (ret > 0)
+ ret = -ENOENT;
+ goto fail;
+ }
+
+ leaf = path->nodes[0];
+ bi = btrfs_item_ptr_offset(leaf, path->slots[0]);
+ write_extent_buffer(leaf, &cache->item, bi, sizeof(cache->item));
+ btrfs_mark_buffer_dirty(leaf);
+fail:
+ btrfs_release_path(path);
+ return ret;
+
+}
+
+static int cache_save_setup(struct btrfs_block_group_cache *block_group,
+ struct btrfs_trans_handle *trans,
+ struct btrfs_path *path)
+{
+ struct btrfs_fs_info *fs_info = block_group->fs_info;
+ struct btrfs_root *root = fs_info->tree_root;
+ struct inode *inode = NULL;
+ struct extent_changeset *data_reserved = NULL;
+ u64 alloc_hint = 0;
+ int dcs = BTRFS_DC_ERROR;
+ u64 num_pages = 0;
+ int retries = 0;
+ int ret = 0;
+
+ /*
+ * If this block group is smaller than 100 megs don't bother caching the
+ * block group.
+ */
+ if (block_group->key.offset < (100 * SZ_1M)) {
+ spin_lock(&block_group->lock);
+ block_group->disk_cache_state = BTRFS_DC_WRITTEN;
+ spin_unlock(&block_group->lock);
+ return 0;
+ }
+
+ if (trans->aborted)
+ return 0;
+again:
+ inode = lookup_free_space_inode(block_group, path);
+ if (IS_ERR(inode) && PTR_ERR(inode) != -ENOENT) {
+ ret = PTR_ERR(inode);
+ btrfs_release_path(path);
+ goto out;
+ }
+
+ if (IS_ERR(inode)) {
+ BUG_ON(retries);
+ retries++;
+
+ if (block_group->ro)
+ goto out_free;
+
+ ret = create_free_space_inode(trans, block_group, path);
+ if (ret)
+ goto out_free;
+ goto again;
+ }
+
+ /*
+ * We want to set the generation to 0, that way if anything goes wrong
+ * from here on out we know not to trust this cache when we load up next
+ * time.
+ */
+ BTRFS_I(inode)->generation = 0;
+ ret = btrfs_update_inode(trans, root, inode);
+ if (ret) {
+ /*
+ * So theoretically we could recover from this, simply set the
+ * super cache generation to 0 so we know to invalidate the
+ * cache, but then we'd have to keep track of the block groups
+ * that fail this way so we know we _have_ to reset this cache
+ * before the next commit or risk reading stale cache. So to
+ * limit our exposure to horrible edge cases lets just abort the
+ * transaction, this only happens in really bad situations
+ * anyway.
+ */
+ btrfs_abort_transaction(trans, ret);
+ goto out_put;
+ }
+ WARN_ON(ret);
+
+ /* We've already setup this transaction, go ahead and exit */
+ if (block_group->cache_generation == trans->transid &&
+ i_size_read(inode)) {
+ dcs = BTRFS_DC_SETUP;
+ goto out_put;
+ }
+
+ if (i_size_read(inode) > 0) {
+ ret = btrfs_check_trunc_cache_free_space(fs_info,
+ &fs_info->global_block_rsv);
+ if (ret)
+ goto out_put;
+
+ ret = btrfs_truncate_free_space_cache(trans, NULL, inode);
+ if (ret)
+ goto out_put;
+ }
+
+ spin_lock(&block_group->lock);
+ if (block_group->cached != BTRFS_CACHE_FINISHED ||
+ !btrfs_test_opt(fs_info, SPACE_CACHE)) {
+ /*
+ * don't bother trying to write stuff out _if_
+ * a) we're not cached,
+ * b) we're with nospace_cache mount option,
+ * c) we're with v2 space_cache (FREE_SPACE_TREE).
+ */
+ dcs = BTRFS_DC_WRITTEN;
+ spin_unlock(&block_group->lock);
+ goto out_put;
+ }
+ spin_unlock(&block_group->lock);
+
+ /*
+ * We hit an ENOSPC when setting up the cache in this transaction, just
+ * skip doing the setup, we've already cleared the cache so we're safe.
+ */
+ if (test_bit(BTRFS_TRANS_CACHE_ENOSPC, &trans->transaction->flags)) {
+ ret = -ENOSPC;
+ goto out_put;
+ }
+
+ /*
+ * Try to preallocate enough space based on how big the block group is.
+ * Keep in mind this has to include any pinned space which could end up
+ * taking up quite a bit since it's not folded into the other space
+ * cache.
+ */
+ num_pages = div_u64(block_group->key.offset, SZ_256M);
+ if (!num_pages)
+ num_pages = 1;
+
+ num_pages *= 16;
+ num_pages *= PAGE_SIZE;
+
+ ret = btrfs_check_data_free_space(inode, &data_reserved, 0, num_pages);
+ if (ret)
+ goto out_put;
+
+ ret = btrfs_prealloc_file_range_trans(inode, trans, 0, 0, num_pages,
+ num_pages, num_pages,
+ &alloc_hint);
+ /*
+ * Our cache requires contiguous chunks so that we don't modify a bunch
+ * of metadata or split extents when writing the cache out, which means
+ * we can enospc if we are heavily fragmented in addition to just normal
+ * out of space conditions. So if we hit this just skip setting up any
+ * other block groups for this transaction, maybe we'll unpin enough
+ * space the next time around.
+ */
+ if (!ret)
+ dcs = BTRFS_DC_SETUP;
+ else if (ret == -ENOSPC)
+ set_bit(BTRFS_TRANS_CACHE_ENOSPC, &trans->transaction->flags);
+
+out_put:
+ iput(inode);
+out_free:
+ btrfs_release_path(path);
+out:
+ spin_lock(&block_group->lock);
+ if (!ret && dcs == BTRFS_DC_SETUP)
+ block_group->cache_generation = trans->transid;
+ block_group->disk_cache_state = dcs;
+ spin_unlock(&block_group->lock);
+
+ extent_changeset_free(data_reserved);
+ return ret;
+}
+
+int btrfs_setup_space_cache(struct btrfs_trans_handle *trans)
+{
+ struct btrfs_fs_info *fs_info = trans->fs_info;
+ struct btrfs_block_group_cache *cache, *tmp;
+ struct btrfs_transaction *cur_trans = trans->transaction;
+ struct btrfs_path *path;
+
+ if (list_empty(&cur_trans->dirty_bgs) ||
+ !btrfs_test_opt(fs_info, SPACE_CACHE))
+ return 0;
+
+ path = btrfs_alloc_path();
+ if (!path)
+ return -ENOMEM;
+
+ /* Could add new block groups, use _safe just in case */
+ list_for_each_entry_safe(cache, tmp, &cur_trans->dirty_bgs,
+ dirty_list) {
+ if (cache->disk_cache_state == BTRFS_DC_CLEAR)
+ cache_save_setup(cache, trans, path);
+ }
+
+ btrfs_free_path(path);
+ return 0;
+}
+
+/*
+ * Transaction commit does final block group cache writeback during a critical
+ * section where nothing is allowed to change the FS. This is required in
+ * order for the cache to actually match the block group, but can introduce a
+ * lot of latency into the commit.
+ *
+ * So, btrfs_start_dirty_block_groups is here to kick off block group cache IO.
+ * There's a chance we'll have to redo some of it if the block group changes
+ * again during the commit, but it greatly reduces the commit latency by
+ * getting rid of the easy block groups while we're still allowing others to
+ * join the commit.
+ */
+int btrfs_start_dirty_block_groups(struct btrfs_trans_handle *trans)
+{
+ struct btrfs_fs_info *fs_info = trans->fs_info;
+ struct btrfs_block_group_cache *cache;
+ struct btrfs_transaction *cur_trans = trans->transaction;
+ int ret = 0;
+ int should_put;
+ struct btrfs_path *path = NULL;
+ LIST_HEAD(dirty);
+ struct list_head *io = &cur_trans->io_bgs;
+ int num_started = 0;
+ int loops = 0;
+
+ spin_lock(&cur_trans->dirty_bgs_lock);
+ if (list_empty(&cur_trans->dirty_bgs)) {
+ spin_unlock(&cur_trans->dirty_bgs_lock);
+ return 0;
+ }
+ list_splice_init(&cur_trans->dirty_bgs, &dirty);
+ spin_unlock(&cur_trans->dirty_bgs_lock);
+
+again:
+ /* Make sure all the block groups on our dirty list actually exist */
+ btrfs_create_pending_block_groups(trans);
+
+ if (!path) {
+ path = btrfs_alloc_path();
+ if (!path)
+ return -ENOMEM;
+ }
+
+ /*
+ * cache_write_mutex is here only to save us from balance or automatic
+ * removal of empty block groups deleting this block group while we are
+ * writing out the cache
+ */
+ mutex_lock(&trans->transaction->cache_write_mutex);
+ while (!list_empty(&dirty)) {
+ bool drop_reserve = true;
+
+ cache = list_first_entry(&dirty,
+ struct btrfs_block_group_cache,
+ dirty_list);
+ /*
+ * This can happen if something re-dirties a block group that
+ * is already under IO. Just wait for it to finish and then do
+ * it all again
+ */
+ if (!list_empty(&cache->io_list)) {
+ list_del_init(&cache->io_list);
+ btrfs_wait_cache_io(trans, cache, path);
+ btrfs_put_block_group(cache);
+ }
+
+
+ /*
+ * btrfs_wait_cache_io uses the cache->dirty_list to decide if
+ * it should update the cache_state. Don't delete until after
+ * we wait.
+ *
+ * Since we're not running in the commit critical section
+ * we need the dirty_bgs_lock to protect from update_block_group
+ */
+ spin_lock(&cur_trans->dirty_bgs_lock);
+ list_del_init(&cache->dirty_list);
+ spin_unlock(&cur_trans->dirty_bgs_lock);
+
+ should_put = 1;
+
+ cache_save_setup(cache, trans, path);
+
+ if (cache->disk_cache_state == BTRFS_DC_SETUP) {
+ cache->io_ctl.inode = NULL;
+ ret = btrfs_write_out_cache(trans, cache, path);
+ if (ret == 0 && cache->io_ctl.inode) {
+ num_started++;
+ should_put = 0;
+
+ /*
+ * The cache_write_mutex is protecting the
+ * io_list, also refer to the definition of
+ * btrfs_transaction::io_bgs for more details
+ */
+ list_add_tail(&cache->io_list, io);
+ } else {
+ /*
+ * If we failed to write the cache, the
+ * generation will be bad and life goes on
+ */
+ ret = 0;
+ }
+ }
+ if (!ret) {
+ ret = write_one_cache_group(trans, path, cache);
+ /*
+ * Our block group might still be attached to the list
+ * of new block groups in the transaction handle of some
+ * other task (struct btrfs_trans_handle->new_bgs). This
+ * means its block group item isn't yet in the extent
+ * tree. If this happens ignore the error, as we will
+ * try again later in the critical section of the
+ * transaction commit.
+ */
+ if (ret == -ENOENT) {
+ ret = 0;
+ spin_lock(&cur_trans->dirty_bgs_lock);
+ if (list_empty(&cache->dirty_list)) {
+ list_add_tail(&cache->dirty_list,
+ &cur_trans->dirty_bgs);
+ btrfs_get_block_group(cache);
+ drop_reserve = false;
+ }
+ spin_unlock(&cur_trans->dirty_bgs_lock);
+ } else if (ret) {
+ btrfs_abort_transaction(trans, ret);
+ }
+ }
+
+ /* If it's not on the io list, we need to put the block group */
+ if (should_put)
+ btrfs_put_block_group(cache);
+ if (drop_reserve)
+ btrfs_delayed_refs_rsv_release(fs_info, 1);
+
+ if (ret)
+ break;
+
+ /*
+ * Avoid blocking other tasks for too long. It might even save
+ * us from writing caches for block groups that are going to be
+ * removed.
+ */
+ mutex_unlock(&trans->transaction->cache_write_mutex);
+ mutex_lock(&trans->transaction->cache_write_mutex);
+ }
+ mutex_unlock(&trans->transaction->cache_write_mutex);
+
+ /*
+ * Go through delayed refs for all the stuff we've just kicked off
+ * and then loop back (just once)
+ */
+ ret = btrfs_run_delayed_refs(trans, 0);
+ if (!ret && loops == 0) {
+ loops++;
+ spin_lock(&cur_trans->dirty_bgs_lock);
+ list_splice_init(&cur_trans->dirty_bgs, &dirty);
+ /*
+ * dirty_bgs_lock protects us from concurrent block group
+ * deletes too (not just cache_write_mutex).
+ */
+ if (!list_empty(&dirty)) {
+ spin_unlock(&cur_trans->dirty_bgs_lock);
+ goto again;
+ }
+ spin_unlock(&cur_trans->dirty_bgs_lock);
+ } else if (ret < 0) {
+ btrfs_cleanup_dirty_bgs(cur_trans, fs_info);
+ }
+
+ btrfs_free_path(path);
+ return ret;
+}
+
+int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans)
+{
+ struct btrfs_fs_info *fs_info = trans->fs_info;
+ struct btrfs_block_group_cache *cache;
+ struct btrfs_transaction *cur_trans = trans->transaction;
+ int ret = 0;
+ int should_put;
+ struct btrfs_path *path;
+ struct list_head *io = &cur_trans->io_bgs;
+ int num_started = 0;
+
+ path = btrfs_alloc_path();
+ if (!path)
+ return -ENOMEM;
+
+ /*
+ * Even though we are in the critical section of the transaction commit,
+ * we can still have concurrent tasks adding elements to this
+ * transaction's list of dirty block groups. These tasks correspond to
+ * endio free space workers started when writeback finishes for a
+ * space cache, which run inode.c:btrfs_finish_ordered_io(), and can
+ * allocate new block groups as a result of COWing nodes of the root
+ * tree when updating the free space inode. The writeback for the space
+ * caches is triggered by an earlier call to
+ * btrfs_start_dirty_block_groups() and iterations of the following
+ * loop.
+ * Also we want to do the cache_save_setup first and then run the
+ * delayed refs to make sure we have the best chance at doing this all
+ * in one shot.
+ */
+ spin_lock(&cur_trans->dirty_bgs_lock);
+ while (!list_empty(&cur_trans->dirty_bgs)) {
+ cache = list_first_entry(&cur_trans->dirty_bgs,
+ struct btrfs_block_group_cache,
+ dirty_list);
+
+ /*
+ * This can happen if cache_save_setup re-dirties a block group
+ * that is already under IO. Just wait for it to finish and
+ * then do it all again
+ */
+ if (!list_empty(&cache->io_list)) {
+ spin_unlock(&cur_trans->dirty_bgs_lock);
+ list_del_init(&cache->io_list);
+ btrfs_wait_cache_io(trans, cache, path);
+ btrfs_put_block_group(cache);
+ spin_lock(&cur_trans->dirty_bgs_lock);
+ }
+
+ /*
+ * Don't remove from the dirty list until after we've waited on
+ * any pending IO
+ */
+ list_del_init(&cache->dirty_list);
+ spin_unlock(&cur_trans->dirty_bgs_lock);
+ should_put = 1;
+
+ cache_save_setup(cache, trans, path);
+
+ if (!ret)
+ ret = btrfs_run_delayed_refs(trans,
+ (unsigned long) -1);
+
+ if (!ret && cache->disk_cache_state == BTRFS_DC_SETUP) {
+ cache->io_ctl.inode = NULL;
+ ret = btrfs_write_out_cache(trans, cache, path);
+ if (ret == 0 && cache->io_ctl.inode) {
+ num_started++;
+ should_put = 0;
+ list_add_tail(&cache->io_list, io);
+ } else {
+ /*
+ * If we failed to write the cache, the
+ * generation will be bad and life goes on
+ */
+ ret = 0;
+ }
+ }
+ if (!ret) {
+ ret = write_one_cache_group(trans, path, cache);
+ /*
+ * One of the free space endio workers might have
+ * created a new block group while updating a free space
+ * cache's inode (at inode.c:btrfs_finish_ordered_io())
+ * and hasn't released its transaction handle yet, in
+ * which case the new block group is still attached to
+ * its transaction handle and its creation has not
+ * finished yet (no block group item in the extent tree
+ * yet, etc). If this is the case, wait for all free
+ * space endio workers to finish and retry. This is a
+ * a very rare case so no need for a more efficient and
+ * complex approach.
+ */
+ if (ret == -ENOENT) {
+ wait_event(cur_trans->writer_wait,
+ atomic_read(&cur_trans->num_writers) == 1);
+ ret = write_one_cache_group(trans, path, cache);
+ }
+ if (ret)
+ btrfs_abort_transaction(trans, ret);
+ }
+
+ /* If its not on the io list, we need to put the block group */
+ if (should_put)
+ btrfs_put_block_group(cache);
+ btrfs_delayed_refs_rsv_release(fs_info, 1);
+ spin_lock(&cur_trans->dirty_bgs_lock);
+ }
+ spin_unlock(&cur_trans->dirty_bgs_lock);
+
+ /*
+ * Refer to the definition of io_bgs member for details why it's safe
+ * to use it without any locking
+ */
+ while (!list_empty(io)) {
+ cache = list_first_entry(io, struct btrfs_block_group_cache,
+ io_list);
+ list_del_init(&cache->io_list);
+ btrfs_wait_cache_io(trans, cache, path);
+ btrfs_put_block_group(cache);
+ }
+
+ btrfs_free_path(path);
+ return ret;
+}
+
+int btrfs_update_block_group(struct btrfs_trans_handle *trans,
+ u64 bytenr, u64 num_bytes, int alloc)
+{
+ struct btrfs_fs_info *info = trans->fs_info;
+ struct btrfs_block_group_cache *cache = NULL;
+ u64 total = num_bytes;
+ u64 old_val;
+ u64 byte_in_group;
+ int factor;
+ int ret = 0;
+
+ /* Block accounting for super block */
+ spin_lock(&info->delalloc_root_lock);
+ old_val = btrfs_super_bytes_used(info->super_copy);
+ if (alloc)
+ old_val += num_bytes;
+ else
+ old_val -= num_bytes;
+ btrfs_set_super_bytes_used(info->super_copy, old_val);
+ spin_unlock(&info->delalloc_root_lock);
+
+ while (total) {
+ cache = btrfs_lookup_block_group(info, bytenr);
+ if (!cache) {
+ ret = -ENOENT;
+ break;
+ }
+ factor = btrfs_bg_type_to_factor(cache->flags);
+
+ /*
+ * If this block group has free space cache written out, we
+ * need to make sure to load it if we are removing space. This
+ * is because we need the unpinning stage to actually add the
+ * space back to the block group, otherwise we will leak space.
+ */
+ if (!alloc && cache->cached == BTRFS_CACHE_NO)
+ btrfs_cache_block_group(cache, 1);
+
+ byte_in_group = bytenr - cache->key.objectid;
+ WARN_ON(byte_in_group > cache->key.offset);
+
+ spin_lock(&cache->space_info->lock);
+ spin_lock(&cache->lock);
+
+ if (btrfs_test_opt(info, SPACE_CACHE) &&
+ cache->disk_cache_state < BTRFS_DC_CLEAR)
+ cache->disk_cache_state = BTRFS_DC_CLEAR;
+
+ old_val = btrfs_block_group_used(&cache->item);
+ num_bytes = min(total, cache->key.offset - byte_in_group);
+ if (alloc) {
+ old_val += num_bytes;
+ btrfs_set_block_group_used(&cache->item, old_val);
+ cache->reserved -= num_bytes;
+ cache->space_info->bytes_reserved -= num_bytes;
+ cache->space_info->bytes_used += num_bytes;
+ cache->space_info->disk_used += num_bytes * factor;
+ spin_unlock(&cache->lock);
+ spin_unlock(&cache->space_info->lock);
+ } else {
+ old_val -= num_bytes;
+ btrfs_set_block_group_used(&cache->item, old_val);
+ cache->pinned += num_bytes;
+ btrfs_space_info_update_bytes_pinned(info,
+ cache->space_info, num_bytes);
+ cache->space_info->bytes_used -= num_bytes;
+ cache->space_info->disk_used -= num_bytes * factor;
+ spin_unlock(&cache->lock);
+ spin_unlock(&cache->space_info->lock);
+
+ percpu_counter_add_batch(
+ &cache->space_info->total_bytes_pinned,
+ num_bytes,
+ BTRFS_TOTAL_BYTES_PINNED_BATCH);
+ set_extent_dirty(info->pinned_extents,
+ bytenr, bytenr + num_bytes - 1,
+ GFP_NOFS | __GFP_NOFAIL);
+ }
+
+ spin_lock(&trans->transaction->dirty_bgs_lock);
+ if (list_empty(&cache->dirty_list)) {
+ list_add_tail(&cache->dirty_list,
+ &trans->transaction->dirty_bgs);
+ trans->delayed_ref_updates++;
+ btrfs_get_block_group(cache);
+ }
+ spin_unlock(&trans->transaction->dirty_bgs_lock);
+
+ /*
+ * No longer have used bytes in this block group, queue it for
+ * deletion. We do this after adding the block group to the
+ * dirty list to avoid races between cleaner kthread and space
+ * cache writeout.
+ */
+ if (!alloc && old_val == 0)
+ btrfs_mark_bg_unused(cache);
+
+ btrfs_put_block_group(cache);
+ total -= num_bytes;
+ bytenr += num_bytes;
+ }
+
+ /* Modified block groups are accounted for in the delayed_refs_rsv. */
+ btrfs_update_delayed_refs_rsv(trans);
+ return ret;
+}
+
+/**
+ * btrfs_add_reserved_bytes - update the block_group and space info counters
+ * @cache: The cache we are manipulating
+ * @ram_bytes: The number of bytes of file content, and will be same to
+ * @num_bytes except for the compress path.
+ * @num_bytes: The number of bytes in question
+ * @delalloc: The blocks are allocated for the delalloc write
+ *
+ * This is called by the allocator when it reserves space. If this is a
+ * reservation and the block group has become read only we cannot make the
+ * reservation and return -EAGAIN, otherwise this function always succeeds.
+ */
+int btrfs_add_reserved_bytes(struct btrfs_block_group_cache *cache,
+ u64 ram_bytes, u64 num_bytes, int delalloc)
+{
+ struct btrfs_space_info *space_info = cache->space_info;
+ int ret = 0;
+
+ spin_lock(&space_info->lock);
+ spin_lock(&cache->lock);
+ if (cache->ro) {
+ ret = -EAGAIN;
+ } else {
+ cache->reserved += num_bytes;
+ space_info->bytes_reserved += num_bytes;
+ trace_btrfs_space_reservation(cache->fs_info, "space_info",
+ space_info->flags, num_bytes, 1);
+ btrfs_space_info_update_bytes_may_use(cache->fs_info,
+ space_info, -ram_bytes);
+ if (delalloc)
+ cache->delalloc_bytes += num_bytes;
+ }
+ spin_unlock(&cache->lock);
+ spin_unlock(&space_info->lock);
+ return ret;
+}
+
+/**
+ * btrfs_free_reserved_bytes - update the block_group and space info counters
+ * @cache: The cache we are manipulating
+ * @num_bytes: The number of bytes in question
+ * @delalloc: The blocks are allocated for the delalloc write
+ *
+ * This is called by somebody who is freeing space that was never actually used
+ * on disk. For example if you reserve some space for a new leaf in transaction
+ * A and before transaction A commits you free that leaf, you call this with
+ * reserve set to 0 in order to clear the reservation.
+ */
+void btrfs_free_reserved_bytes(struct btrfs_block_group_cache *cache,
+ u64 num_bytes, int delalloc)
+{
+ struct btrfs_space_info *space_info = cache->space_info;
+
+ spin_lock(&space_info->lock);
+ spin_lock(&cache->lock);
+ if (cache->ro)
+ space_info->bytes_readonly += num_bytes;
+ cache->reserved -= num_bytes;
+ space_info->bytes_reserved -= num_bytes;
+ space_info->max_extent_size = 0;
+
+ if (delalloc)
+ cache->delalloc_bytes -= num_bytes;
+ spin_unlock(&cache->lock);
+ spin_unlock(&space_info->lock);
+}
+
+static void force_metadata_allocation(struct btrfs_fs_info *info)
+{
+ struct list_head *head = &info->space_info;
+ struct btrfs_space_info *found;
+
+ rcu_read_lock();
+ list_for_each_entry_rcu(found, head, list) {
+ if (found->flags & BTRFS_BLOCK_GROUP_METADATA)
+ found->force_alloc = CHUNK_ALLOC_FORCE;
+ }
+ rcu_read_unlock();
+}
+
+static int should_alloc_chunk(struct btrfs_fs_info *fs_info,
+ struct btrfs_space_info *sinfo, int force)
+{
+ u64 bytes_used = btrfs_space_info_used(sinfo, false);
+ u64 thresh;
+
+ if (force == CHUNK_ALLOC_FORCE)
+ return 1;
+
+ /*
+ * in limited mode, we want to have some free space up to
+ * about 1% of the FS size.
+ */
+ if (force == CHUNK_ALLOC_LIMITED) {
+ thresh = btrfs_super_total_bytes(fs_info->super_copy);
+ thresh = max_t(u64, SZ_64M, div_factor_fine(thresh, 1));
+
+ if (sinfo->total_bytes - bytes_used < thresh)
+ return 1;
+ }
+
+ if (bytes_used + SZ_2M < div_factor(sinfo->total_bytes, 8))
+ return 0;
+ return 1;
+}
+
+int btrfs_force_chunk_alloc(struct btrfs_trans_handle *trans, u64 type)
+{
+ u64 alloc_flags = btrfs_get_alloc_profile(trans->fs_info, type);
+
+ return btrfs_chunk_alloc(trans, alloc_flags, CHUNK_ALLOC_FORCE);
+}
+
+/*
+ * If force is CHUNK_ALLOC_FORCE:
+ * - return 1 if it successfully allocates a chunk,
+ * - return errors including -ENOSPC otherwise.
+ * If force is NOT CHUNK_ALLOC_FORCE:
+ * - return 0 if it doesn't need to allocate a new chunk,
+ * - return 1 if it successfully allocates a chunk,
+ * - return errors including -ENOSPC otherwise.
+ */
+int btrfs_chunk_alloc(struct btrfs_trans_handle *trans, u64 flags,
+ enum btrfs_chunk_alloc_enum force)
+{
+ struct btrfs_fs_info *fs_info = trans->fs_info;
+ struct btrfs_space_info *space_info;
+ bool wait_for_alloc = false;
+ bool should_alloc = false;
+ int ret = 0;
+
+ /* Don't re-enter if we're already allocating a chunk */
+ if (trans->allocating_chunk)
+ return -ENOSPC;
+
+ space_info = btrfs_find_space_info(fs_info, flags);
+ ASSERT(space_info);
+
+ do {
+ spin_lock(&space_info->lock);
+ if (force < space_info->force_alloc)
+ force = space_info->force_alloc;
+ should_alloc = should_alloc_chunk(fs_info, space_info, force);
+ if (space_info->full) {
+ /* No more free physical space */
+ if (should_alloc)
+ ret = -ENOSPC;
+ else
+ ret = 0;
+ spin_unlock(&space_info->lock);
+ return ret;
+ } else if (!should_alloc) {
+ spin_unlock(&space_info->lock);
+ return 0;
+ } else if (space_info->chunk_alloc) {
+ /*
+ * Someone is already allocating, so we need to block
+ * until this someone is finished and then loop to
+ * recheck if we should continue with our allocation
+ * attempt.
+ */
+ wait_for_alloc = true;
+ spin_unlock(&space_info->lock);
+ mutex_lock(&fs_info->chunk_mutex);
+ mutex_unlock(&fs_info->chunk_mutex);
+ } else {
+ /* Proceed with allocation */
+ space_info->chunk_alloc = 1;
+ wait_for_alloc = false;
+ spin_unlock(&space_info->lock);
+ }
+
+ cond_resched();
+ } while (wait_for_alloc);
+
+ mutex_lock(&fs_info->chunk_mutex);
+ trans->allocating_chunk = true;
+
+ /*
+ * If we have mixed data/metadata chunks we want to make sure we keep
+ * allocating mixed chunks instead of individual chunks.
+ */
+ if (btrfs_mixed_space_info(space_info))
+ flags |= (BTRFS_BLOCK_GROUP_DATA | BTRFS_BLOCK_GROUP_METADATA);
+
+ /*
+ * if we're doing a data chunk, go ahead and make sure that
+ * we keep a reasonable number of metadata chunks allocated in the
+ * FS as well.
+ */
+ if (flags & BTRFS_BLOCK_GROUP_DATA && fs_info->metadata_ratio) {
+ fs_info->data_chunk_allocations++;
+ if (!(fs_info->data_chunk_allocations %
+ fs_info->metadata_ratio))
+ force_metadata_allocation(fs_info);
+ }
+
+ /*
+ * Check if we have enough space in SYSTEM chunk because we may need
+ * to update devices.
+ */
+ check_system_chunk(trans, flags);
+
+ ret = btrfs_alloc_chunk(trans, flags);
+ trans->allocating_chunk = false;
+
+ spin_lock(&space_info->lock);
+ if (ret < 0) {
+ if (ret == -ENOSPC)
+ space_info->full = 1;
+ else
+ goto out;
+ } else {
+ ret = 1;
+ space_info->max_extent_size = 0;
+ }
+
+ space_info->force_alloc = CHUNK_ALLOC_NO_FORCE;
+out:
+ space_info->chunk_alloc = 0;
+ spin_unlock(&space_info->lock);
+ mutex_unlock(&fs_info->chunk_mutex);
+ /*
+ * When we allocate a new chunk we reserve space in the chunk block
+ * reserve to make sure we can COW nodes/leafs in the chunk tree or
+ * add new nodes/leafs to it if we end up needing to do it when
+ * inserting the chunk item and updating device items as part of the
+ * second phase of chunk allocation, performed by
+ * btrfs_finish_chunk_alloc(). So make sure we don't accumulate a
+ * large number of new block groups to create in our transaction
+ * handle's new_bgs list to avoid exhausting the chunk block reserve
+ * in extreme cases - like having a single transaction create many new
+ * block groups when starting to write out the free space caches of all
+ * the block groups that were made dirty during the lifetime of the
+ * transaction.
+ */
+ if (trans->chunk_bytes_reserved >= (u64)SZ_2M)
+ btrfs_create_pending_block_groups(trans);
+
+ return ret;
+}
+
+static u64 get_profile_num_devs(struct btrfs_fs_info *fs_info, u64 type)
+{
+ u64 num_dev;
+
+ num_dev = btrfs_raid_array[btrfs_bg_flags_to_raid_index(type)].devs_max;
+ if (!num_dev)
+ num_dev = fs_info->fs_devices->rw_devices;
+
+ return num_dev;
+}
+
+/*
+ * If @is_allocation is true, reserve space in the system space info necessary
+ * for allocating a chunk, otherwise if it's false, reserve space necessary for
+ * removing a chunk.
+ */
+void check_system_chunk(struct btrfs_trans_handle *trans, u64 type)
+{
+ struct btrfs_fs_info *fs_info = trans->fs_info;
+ struct btrfs_space_info *info;
+ u64 left;
+ u64 thresh;
+ int ret = 0;
+ u64 num_devs;
+
+ /*
+ * Needed because we can end up allocating a system chunk and for an
+ * atomic and race free space reservation in the chunk block reserve.
+ */
+ lockdep_assert_held(&fs_info->chunk_mutex);
+
+ info = btrfs_find_space_info(fs_info, BTRFS_BLOCK_GROUP_SYSTEM);
+ spin_lock(&info->lock);
+ left = info->total_bytes - btrfs_space_info_used(info, true);
+ spin_unlock(&info->lock);
+
+ num_devs = get_profile_num_devs(fs_info, type);
+
+ /* num_devs device items to update and 1 chunk item to add or remove */
+ thresh = btrfs_calc_metadata_size(fs_info, num_devs) +
+ btrfs_calc_insert_metadata_size(fs_info, 1);
+
+ if (left < thresh && btrfs_test_opt(fs_info, ENOSPC_DEBUG)) {
+ btrfs_info(fs_info, "left=%llu, need=%llu, flags=%llu",
+ left, thresh, type);
+ btrfs_dump_space_info(fs_info, info, 0, 0);
+ }
+
+ if (left < thresh) {
+ u64 flags = btrfs_system_alloc_profile(fs_info);
+
+ /*
+ * Ignore failure to create system chunk. We might end up not
+ * needing it, as we might not need to COW all nodes/leafs from
+ * the paths we visit in the chunk tree (they were already COWed
+ * or created in the current transaction for example).
+ */
+ ret = btrfs_alloc_chunk(trans, flags);
+ }
+
+ if (!ret) {
+ ret = btrfs_block_rsv_add(fs_info->chunk_root,
+ &fs_info->chunk_block_rsv,
+ thresh, BTRFS_RESERVE_NO_FLUSH);
+ if (!ret)
+ trans->chunk_bytes_reserved += thresh;
+ }
+}
+
+void btrfs_put_block_group_cache(struct btrfs_fs_info *info)
+{
+ struct btrfs_block_group_cache *block_group;
+ u64 last = 0;
+
+ while (1) {
+ struct inode *inode;
+
+ block_group = btrfs_lookup_first_block_group(info, last);
+ while (block_group) {
+ btrfs_wait_block_group_cache_done(block_group);
+ spin_lock(&block_group->lock);
+ if (block_group->iref)
+ break;
+ spin_unlock(&block_group->lock);
+ block_group = btrfs_next_block_group(block_group);
+ }
+ if (!block_group) {
+ if (last == 0)
+ break;
+ last = 0;
+ continue;
+ }
+
+ inode = block_group->inode;
+ block_group->iref = 0;
+ block_group->inode = NULL;
+ spin_unlock(&block_group->lock);
+ ASSERT(block_group->io_ctl.inode == NULL);
+ iput(inode);
+ last = block_group->key.objectid + block_group->key.offset;
+ btrfs_put_block_group(block_group);
+ }
+}
+
+/*
+ * Must be called only after stopping all workers, since we could have block
+ * group caching kthreads running, and therefore they could race with us if we
+ * freed the block groups before stopping them.
+ */
+int btrfs_free_block_groups(struct btrfs_fs_info *info)
+{
+ struct btrfs_block_group_cache *block_group;
+ struct btrfs_space_info *space_info;
+ struct btrfs_caching_control *caching_ctl;
+ struct rb_node *n;
+
+ down_write(&info->commit_root_sem);
+ while (!list_empty(&info->caching_block_groups)) {
+ caching_ctl = list_entry(info->caching_block_groups.next,
+ struct btrfs_caching_control, list);
+ list_del(&caching_ctl->list);
+ btrfs_put_caching_control(caching_ctl);
+ }
+ up_write(&info->commit_root_sem);
+
+ spin_lock(&info->unused_bgs_lock);
+ while (!list_empty(&info->unused_bgs)) {
+ block_group = list_first_entry(&info->unused_bgs,
+ struct btrfs_block_group_cache,
+ bg_list);
+ list_del_init(&block_group->bg_list);
+ btrfs_put_block_group(block_group);
+ }
+ spin_unlock(&info->unused_bgs_lock);
+
+ spin_lock(&info->block_group_cache_lock);
+ while ((n = rb_last(&info->block_group_cache_tree)) != NULL) {
+ block_group = rb_entry(n, struct btrfs_block_group_cache,
+ cache_node);
+ rb_erase(&block_group->cache_node,
+ &info->block_group_cache_tree);
+ RB_CLEAR_NODE(&block_group->cache_node);
+ spin_unlock(&info->block_group_cache_lock);
+
+ down_write(&block_group->space_info->groups_sem);
+ list_del(&block_group->list);
+ up_write(&block_group->space_info->groups_sem);
+
+ /*
+ * We haven't cached this block group, which means we could
+ * possibly have excluded extents on this block group.
+ */
+ if (block_group->cached == BTRFS_CACHE_NO ||
+ block_group->cached == BTRFS_CACHE_ERROR)
+ btrfs_free_excluded_extents(block_group);
+
+ btrfs_remove_free_space_cache(block_group);
+ ASSERT(block_group->cached != BTRFS_CACHE_STARTED);
+ ASSERT(list_empty(&block_group->dirty_list));
+ ASSERT(list_empty(&block_group->io_list));
+ ASSERT(list_empty(&block_group->bg_list));
+ ASSERT(atomic_read(&block_group->count) == 1);
+ btrfs_put_block_group(block_group);
+
+ spin_lock(&info->block_group_cache_lock);
+ }
+ spin_unlock(&info->block_group_cache_lock);
+
+ /*
+ * Now that all the block groups are freed, go through and free all the
+ * space_info structs. This is only called during the final stages of
+ * unmount, and so we know nobody is using them. We call
+ * synchronize_rcu() once before we start, just to be on the safe side.
+ */
+ synchronize_rcu();
+
+ btrfs_release_global_block_rsv(info);
+
+ while (!list_empty(&info->space_info)) {
+ space_info = list_entry(info->space_info.next,
+ struct btrfs_space_info,
+ list);
+
+ /*
+ * Do not hide this behind enospc_debug, this is actually
+ * important and indicates a real bug if this happens.
+ */
+ if (WARN_ON(space_info->bytes_pinned > 0 ||
+ space_info->bytes_reserved > 0 ||
+ space_info->bytes_may_use > 0))
+ btrfs_dump_space_info(info, space_info, 0, 0);
+ list_del(&space_info->list);
+ btrfs_sysfs_remove_space_info(space_info);
+ }
+ return 0;
+}