Add the fs-global state and initialization for snapshot deletion
Signed-off-by: Arne Jansen <sensille@xxxxxxx>
---
fs/btrfs/ctree.h | 35 +++++++++++++++++++++++++++++++++++
fs/btrfs/disk-io.c | 18 ++++++++++++++++++
2 files changed, 53 insertions(+), 0 deletions(-)
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index e187ab9..8eb0795 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -1257,6 +1257,41 @@ struct btrfs_fs_info {
/* next backup root to be overwritten */
int backup_root_index;
+
+ /*
+ * global state for snapshot deletion via readahead. All fields are
+ * protected by droptree_lock. droptree_lock is a mutex and not a
+ * spinlock as allocations are done inside and we don't want to use
+ * atomic allocations unless we really have to.
+ */
+ struct mutex droptree_lock;
+
+ /*
+ * currently running requests (droptree_nodes) for each level and
+ * the corresponding limits. It's necessary to limit them to have
+ * an upper limit on the state that has to be written with each
+ * commit. All nodes exceeding the limit are enqueued to droptree_queue.
+ */
+ long droptree_req[BTRFS_MAX_LEVEL + 1];
+ long droptree_limit[BTRFS_MAX_LEVEL + 1];
+ struct list_head droptree_queue[BTRFS_MAX_LEVEL + 1];
+
+ /*
+ * when droptree is paused, all currently running requests are moved
+ * to droptree_restart. All nodes in droptree_queue are moved to
+ * droptree_requeue
+ */
+ struct list_head droptree_restart;
+ struct list_head droptree_requeue;
+
+ /*
+ * synchronization for pause/restart. droptree_rc is the top-level
+ * reada_control, used to cancel all running requests
+ */
+ int droptrees_running;
+ int droptree_pause_req;
+ wait_queue_head_t droptree_wait;
+ struct reada_control *droptree_rc;
};
/*
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index b801d29..7b3ddd7 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -1911,6 +1911,7 @@ struct btrfs_root *open_ctree(struct super_block *sb,
int err = -EINVAL;
int num_backups_tried = 0;
int backup_index = 0;
+ int i;
extent_root = fs_info->extent_root =
kzalloc(sizeof(struct btrfs_root), GFP_NOFS);
@@ -1989,6 +1990,23 @@ struct btrfs_root *open_ctree(struct super_block *sb,
INIT_RADIX_TREE(&fs_info->reada_tree, GFP_NOFS & ~__GFP_WAIT);
spin_lock_init(&fs_info->reada_lock);
+ /* snapshot deletion state */
+ mutex_init(&fs_info->droptree_lock);
+ fs_info->droptree_pause_req = 0;
+ fs_info->droptrees_running = 0;
+ for (i = 0; i < BTRFS_MAX_LEVEL; ++i) {
+ fs_info->droptree_limit[i] = 100;
+ fs_info->droptree_req[i] = 0;
+ INIT_LIST_HEAD(fs_info->droptree_queue + i);
+ }
+ /* FIXME calculate some sane values, maybe based on avail RAM */
+ fs_info->droptree_limit[0] = 40000;
+ fs_info->droptree_limit[1] = 10000;
+ fs_info->droptree_limit[2] = 4000;
+ INIT_LIST_HEAD(&fs_info->droptree_restart);
+ INIT_LIST_HEAD(&fs_info->droptree_requeue);
+ init_waitqueue_head(&fs_info->droptree_wait);
+
fs_info->thread_pool_size = min_t(unsigned long,
num_online_cpus() + 2, 8);
--
1.7.3.4
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