btrfs: switch inode_cache option handling to pending changes

The pending mount option(s) now share namespace and bits with the normal
options, and the existing one for (inode_cache) is unset unconditionally
at each transaction commit.

Introduce a separate namespace for pending changes and enhance the
descriptions of the intended change to use separate bits for each
action.

Signed-off-by: David Sterba <dsterba@suse.cz>

5 files changed, 18 insertions, 15 deletions

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index f30b061ef77d..1c9157e4ab0c 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -2098,7 +2098,6 @@ struct btrfs_ioctl_defrag_range_args {
 #define BTRFS_MOUNT_CHECK_INTEGRITY_INCLUDING_EXTENT_DATA (1 << 21)
 #define BTRFS_MOUNT_PANIC_ON_FATAL_ERROR        (1 << 22)
 #define BTRFS_MOUNT_RESCAN_UUID_TREE    (1 << 23)
-#define BTRFS_MOUNT_CHANGE_INODE_CACHE  (1 << 24)
 
 #define BTRFS_DEFAULT_COMMIT_INTERVAL   (30)
 #define BTRFS_DEFAULT_MAX_INLINE        (8192)
@@ -2131,6 +2130,9 @@ struct btrfs_ioctl_defrag_range_args {
  * transaction commit)
  */
 
+#define BTRFS_PENDING_SET_INODE_MAP_CACHE       (0)
+#define BTRFS_PENDING_CLEAR_INODE_MAP_CACHE     (1)
+
 #define btrfs_test_pending(info, opt)   \
         test_bit(BTRFS_PENDING_##opt, &(info)->pending_changes)
 #define btrfs_set_pending(info, opt)    \
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index fd80c0d98421..6b406e3f3abe 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -2830,10 +2830,6 @@ retry_root_backup:
                 btrfs_set_opt(fs_info->mount_opt, SSD);
         }
 
-        /* Set the real inode map cache flag */
-        if (btrfs_test_opt(tree_root, CHANGE_INODE_CACHE))
-                btrfs_set_opt(tree_root->fs_info->mount_opt, INODE_MAP_CACHE);
-
         /*
          * Mount does not set all options immediatelly, we can do it now and do
          * not have to wait for transaction commit
diff --git a/fs/btrfs/inode-map.c b/fs/btrfs/inode-map.c
index 83d646bd2e4b..4ebd5ebb1ea1 100644
--- a/fs/btrfs/inode-map.c
+++ b/fs/btrfs/inode-map.c
@@ -178,7 +178,7 @@ static void start_caching(struct btrfs_root *root)
                           root->root_key.objectid);
         if (IS_ERR(tsk)) {
                 btrfs_warn(root->fs_info, "failed to start inode caching task");
-                btrfs_clear_and_info(root, CHANGE_INODE_CACHE,
+                btrfs_clear_pending_and_info(root->fs_info, INODE_MAP_CACHE,
                                 "disabling inode map caching");
         }
 }
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index 1da16d59e115..65c75d9e9750 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -642,11 +642,11 @@ int btrfs_parse_options(struct btrfs_root *root, char *options)
                                              "disabling disk space caching");
                         break;
                 case Opt_inode_cache:
-                        btrfs_set_and_info(root, CHANGE_INODE_CACHE,
+                        btrfs_set_pending_and_info(info, INODE_MAP_CACHE,
                                            "enabling inode map caching");
                         break;
                 case Opt_noinode_cache:
-                        btrfs_clear_and_info(root, CHANGE_INODE_CACHE,
+                        btrfs_clear_pending_and_info(info, INODE_MAP_CACHE,
                                              "disabling inode map caching");
                         break;
                 case Opt_clear_cache:
diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
index 7a4024a55e5c..703238ed7337 100644
--- a/fs/btrfs/transaction.c
+++ b/fs/btrfs/transaction.c
@@ -1842,14 +1842,9 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
         }
 
         /*
-         * Since the transaction is done, we should set the inode map cache flag
-         * before any other comming transaction.
+         * Since the transaction is done, we can apply the pending changes
+         * before the next transaction.
          */
-        if (btrfs_test_opt(root, CHANGE_INODE_CACHE))
-                btrfs_set_opt(root->fs_info->mount_opt, INODE_MAP_CACHE);
-        else
-                btrfs_clear_opt(root->fs_info->mount_opt, INODE_MAP_CACHE);
-
         btrfs_apply_pending_changes(root->fs_info);
 
         /* commit_fs_roots gets rid of all the tree log roots, it is now
@@ -2031,6 +2026,16 @@ void btrfs_apply_pending_changes(struct btrfs_fs_info *fs_info)
         if (!prev)
                 return;
 
+        bit = 1 << BTRFS_PENDING_SET_INODE_MAP_CACHE;
+        if (prev & bit)
+                btrfs_set_opt(fs_info->mount_opt, INODE_MAP_CACHE);
+        prev &= ~bit;
+
+        bit = 1 << BTRFS_PENDING_CLEAR_INODE_MAP_CACHE;
+        if (prev & bit)
+                btrfs_clear_opt(fs_info->mount_opt, INODE_MAP_CACHE);
+        prev &= ~bit;
+
         if (prev)
                 btrfs_warn(fs_info,
                         "unknown pending changes left 0x%lx, ignoring", prev);