Btrfs: Introduce contexts for metadata reservation

Introducing metadata reseravtion contexts has two major advantages.
First, it makes metadata reseravtion more traceable. Second, it can
reclaim freed space and re-add them to the itself after transaction
committed.

Besides add btrfs_block_rsv structure and related helper functions,
This patch contains following changes:

Move code that decides if freed tree block should be pinned into
btrfs_free_tree_block().

Make space accounting more accurate, mainly for handling read only
block groups.

Signed-off-by: Chris Mason <chris.mason@oracle.com>

1 files changed, 62 insertions, 7 deletions

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 85c7b95dd2fe..7d2479694a58 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -707,6 +707,20 @@ struct btrfs_space_info {
         atomic_t caching_threads;
 };
 
+struct btrfs_block_rsv {
+        u64 size;
+        u64 reserved;
+        u64 freed[2];
+        struct btrfs_space_info *space_info;
+        struct list_head list;
+        spinlock_t lock;
+        atomic_t usage;
+        unsigned int priority:8;
+        unsigned int durable:1;
+        unsigned int refill_used:1;
+        unsigned int full:1;
+};
+
 /*
  * free clusters are used to claim free space in relatively large chunks,
  * allowing us to do less seeky writes.  They are used for all metadata
@@ -757,6 +771,7 @@ struct btrfs_block_group_cache {
         spinlock_t lock;
         u64 pinned;
         u64 reserved;
+        u64 reserved_pinned;
         u64 bytes_super;
         u64 flags;
         u64 sectorsize;
@@ -822,6 +837,22 @@ struct btrfs_fs_info {
         /* logical->physical extent mapping */
         struct btrfs_mapping_tree mapping_tree;
 
+        /* block reservation for extent, checksum and root tree */
+        struct btrfs_block_rsv global_block_rsv;
+        /* block reservation for delay allocation */
+        struct btrfs_block_rsv delalloc_block_rsv;
+        /* block reservation for metadata operations */
+        struct btrfs_block_rsv trans_block_rsv;
+        /* block reservation for chunk tree */
+        struct btrfs_block_rsv chunk_block_rsv;
+
+        struct btrfs_block_rsv empty_block_rsv;
+
+        /* list of block reservations that cross multiple transactions */
+        struct list_head durable_block_rsv_list;
+
+        struct mutex durable_block_rsv_mutex;
+
         u64 generation;
         u64 last_trans_committed;
 
@@ -1008,6 +1039,9 @@ struct btrfs_root {
         struct completion kobj_unregister;
         struct mutex objectid_mutex;
 
+        spinlock_t accounting_lock;
+        struct btrfs_block_rsv *block_rsv;
+
         struct mutex log_mutex;
         wait_queue_head_t log_writer_wait;
         wait_queue_head_t log_commit_wait[2];
@@ -1980,10 +2014,10 @@ struct extent_buffer *btrfs_alloc_free_block(struct btrfs_trans_handle *trans,
                                         u64 parent, u64 root_objectid,
                                         struct btrfs_disk_key *key, int level,
                                         u64 hint, u64 empty_size);
-int btrfs_free_tree_block(struct btrfs_trans_handle *trans,
-                          struct btrfs_root *root,
-                          u64 bytenr, u32 blocksize,
-                          u64 parent, u64 root_objectid, int level);
+void btrfs_free_tree_block(struct btrfs_trans_handle *trans,
+                           struct btrfs_root *root,
+                           struct extent_buffer *buf,
+                           u64 parent, int last_ref);
 struct extent_buffer *btrfs_init_new_buffer(struct btrfs_trans_handle *trans,
                                             struct btrfs_root *root,
                                             u64 bytenr, u32 blocksize,
@@ -2037,9 +2071,6 @@ int btrfs_make_block_group(struct btrfs_trans_handle *trans,
                            u64 size);
 int btrfs_remove_block_group(struct btrfs_trans_handle *trans,
                              struct btrfs_root *root, u64 group_start);
-int btrfs_prepare_block_group_relocation(struct btrfs_root *root,
-                                struct btrfs_block_group_cache *group);
-
 u64 btrfs_reduce_alloc_profile(struct btrfs_root *root, u64 flags);
 void btrfs_set_inode_space_info(struct btrfs_root *root, struct inode *ionde);
 void btrfs_clear_space_info_full(struct btrfs_fs_info *info);
@@ -2058,6 +2089,30 @@ void btrfs_delalloc_reserve_space(struct btrfs_root *root, struct inode *inode,
                                  u64 bytes);
 void btrfs_delalloc_free_space(struct btrfs_root *root, struct inode *inode,
                               u64 bytes);
+void btrfs_init_block_rsv(struct btrfs_block_rsv *rsv);
+struct btrfs_block_rsv *btrfs_alloc_block_rsv(struct btrfs_root *root);
+void btrfs_free_block_rsv(struct btrfs_root *root,
+                          struct btrfs_block_rsv *rsv);
+void btrfs_add_durable_block_rsv(struct btrfs_fs_info *fs_info,
+                                 struct btrfs_block_rsv *rsv);
+int btrfs_block_rsv_add(struct btrfs_trans_handle *trans,
+                        struct btrfs_root *root,
+                        struct btrfs_block_rsv *block_rsv,
+                        u64 num_bytes, int *retries);
+int btrfs_block_rsv_check(struct btrfs_trans_handle *trans,
+                          struct btrfs_root *root,
+                          struct btrfs_block_rsv *block_rsv,
+                          u64 min_reserved, int min_factor);
+int btrfs_block_rsv_migrate(struct btrfs_block_rsv *src_rsv,
+                            struct btrfs_block_rsv *dst_rsv,
+                            u64 num_bytes);
+void btrfs_block_rsv_release(struct btrfs_root *root,
+                             struct btrfs_block_rsv *block_rsv,
+                             u64 num_bytes);
+int btrfs_set_block_group_ro(struct btrfs_root *root,
+                             struct btrfs_block_group_cache *cache);
+int btrfs_set_block_group_rw(struct btrfs_root *root,
+                             struct btrfs_block_group_cache *cache);
 /* ctree.c */
 int btrfs_bin_search(struct extent_buffer *eb, struct btrfs_key *key,
                      int level, int *slot);