Btrfs: use signed integer instead of unsigned long integer for log transid

The log trans id is initialized to be 0 every time we create a log tree,
and the log tree need be re-created after a new transaction is started,
it means the log trans id is unlikely to be a huge number, so we can use
signed integer instead of unsigned long integer to save a bit space.

Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Josef Bacik <jbacik@fb.com>

3 files changed, 11 insertions, 11 deletions

diff --git a/fs/btrfs/btrfs_inode.h b/fs/btrfs/btrfs_inode.h
index 8fed2125689e..c9a24444ec9a 100644
--- a/fs/btrfs/btrfs_inode.h
+++ b/fs/btrfs/btrfs_inode.h
@@ -109,14 +109,17 @@ struct btrfs_inode {
         u64 last_trans;
 
         /*
-         * log transid when this inode was last modified
+         * transid that last logged this inode
          */
-        u64 last_sub_trans;
+        u64 logged_trans;
 
         /*
-         * transid that last logged this inode
+         * log transid when this inode was last modified
          */
-        u64 logged_trans;
+        int last_sub_trans;
+
+        /* a local copy of root's last_log_commit */
+        int last_log_commit;
 
         /* total number of bytes pending delalloc, used by stat to calc the
          * real block usage of the file
@@ -155,9 +158,6 @@ struct btrfs_inode {
         /* flags field from the on disk inode */
         u32 flags;
 
-        /* a local copy of root's last_log_commit */
-        unsigned long last_log_commit;
-
         /*
          * Counters to keep track of the number of extent item's we may use due
          * to delalloc and such.  outstanding_extents is the number of extent
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index dac6653d4cce..70c03f5f0953 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -1721,8 +1721,8 @@ struct btrfs_root {
         atomic_t log_writers;
         atomic_t log_commit[2];
         atomic_t log_batch;
-        unsigned long log_transid;
-        unsigned long last_log_commit;
+        int log_transid;
+        int last_log_commit;
         pid_t log_start_pid;
         bool log_multiple_pids;
 
diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c
index 285c168391f3..128a904ceac0 100644
--- a/fs/btrfs/tree-log.c
+++ b/fs/btrfs/tree-log.c
@@ -2362,7 +2362,7 @@ static int update_log_root(struct btrfs_trans_handle *trans,
 }
 
 static int wait_log_commit(struct btrfs_trans_handle *trans,
-                           struct btrfs_root *root, unsigned long transid)
+                           struct btrfs_root *root, int transid)
 {
         DEFINE_WAIT(wait);
         int index = transid % 2;
@@ -2434,7 +2434,7 @@ int btrfs_sync_log(struct btrfs_trans_handle *trans,
         int ret;
         struct btrfs_root *log = root->log_root;
         struct btrfs_root *log_root_tree = root->fs_info->log_root_tree;
-        unsigned long log_transid = 0;
+        int log_transid = 0;
         struct blk_plug plug;
 
         mutex_lock(&root->log_mutex);