btrfs: use a negative value for BTRFS_LOG_FORCE_COMMIT

Currently we use the value 1 for BTRFS_LOG_FORCE_COMMIT, but that value
has a few inconveniences:

1) If it's ever used by btrfs_log_inode(), or any function down the call
   chain, we have to remember to btrfs_set_log_full_commit(), which is
   repetitive and has a chance to be forgotten in future use cases.
   btrfs_log_inode_parent() only calls btrfs_set_log_full_commit() when
   it gets a negative value from btrfs_log_inode();

2) Down the call chain of btrfs_log_inode(), we may have functions that
   need to force a log commit, but can return either an error (negative
   value), false (0) or true (1). So they are forced to return some
   random negative to force a log commit - using BTRFS_LOG_FORCE_COMMIT
   would make the intention more clear. Currently the only example is
   flush_dir_items_batch().

So turn BTRFS_LOG_FORCE_COMMIT into a negative value. The chosen value
is -(MAX_ERRNO + 1), so that it does not overlap any errno value and makes
it easier to debug.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c
index 58599189bd1886165e556458ba81e603f258b8fa..94fc8b08254c17e7869e30a9005e0f5a32d7f77d 100644 (file)
--- a/fs/btrfs/tree-log.c
+++ b/fs/btrfs/tree-log.c
@@ -3652,11 +3652,10 @@ static int flush_dir_items_batch(struct btrfs_trans_handle *trans,
 
        /*
         * If for some unexpected reason the last item's index is not greater
-        * than the last index we logged, warn and return an error to fallback
-        * to a transaction commit.
+        * than the last index we logged, warn and force a transaction commit.
         */
        if (WARN_ON(last_index <= inode->last_dir_index_offset))
-               ret = -EUCLEAN;
+               ret = BTRFS_LOG_FORCE_COMMIT;
        else
                inode->last_dir_index_offset = last_index;
 out:
@@ -5604,10 +5603,8 @@ static int add_conflicting_inode(struct btrfs_trans_handle *trans,
         * LOG_INODE_EXISTS mode) and slow down other fsyncs or transaction
         * commits.
         */
-       if (ctx->num_conflict_inodes >= MAX_CONFLICT_INODES) {
-               btrfs_set_log_full_commit(trans);
+       if (ctx->num_conflict_inodes >= MAX_CONFLICT_INODES)
                return BTRFS_LOG_FORCE_COMMIT;
-       }
 
        inode = btrfs_iget(root->fs_info->sb, ino, root);
        /*
@@ -6466,7 +6463,6 @@ static int btrfs_log_inode(struct btrfs_trans_handle *trans,
         * result in losing the file after a log replay.
         */
        if (full_dir_logging && inode->last_unlink_trans >= trans->transid) {
-               btrfs_set_log_full_commit(trans);
                ret = BTRFS_LOG_FORCE_COMMIT;
                goto out_unlock;
        }

diff --git a/fs/btrfs/tree-log.h b/fs/btrfs/tree-log.h
index 85cd24cb0540d193942d749f2b811ccdef1c3d6d..bdeb5216718f4faf343296c4119325ff53fedbcb 100644 (file)
--- a/fs/btrfs/tree-log.h
+++ b/fs/btrfs/tree-log.h
@@ -13,8 +13,13 @@
 /* return value for btrfs_log_dentry_safe that means we don't need to log it at all */
 #define BTRFS_NO_LOG_SYNC 256
 
-/* We can't use the tree log for whatever reason, force a transaction commit */
-#define BTRFS_LOG_FORCE_COMMIT                         (1)
+/*
+ * We can't use the tree log for whatever reason, force a transaction commit.
+ * We use a negative value because there are functions through the logging code
+ * that need to return an error (< 0 value), false (0) or true (1). Any negative
+ * value will do, as it will cause the log to be marked for a full sync.
+ */
+#define BTRFS_LOG_FORCE_COMMIT                         (-(MAX_ERRNO + 1))
 
 struct btrfs_log_ctx {
        int log_ret;