Btrfs devel - Jan 2013 - [PATCH 03/11] Btrfs: use atomic for fs_info->last_trans_log_full_commit

fs_info->last_trans_log_full_commit is a 64bits variant, we might get a
wrong value on the 32bit machines if we access it directly. Fix it by atomic
operation.

Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com>
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
---
 fs/btrfs/ctree.h       |  2 +-
 fs/btrfs/extent-tree.c |  3 ++-
 fs/btrfs/inode.c       |  3 ++-
 fs/btrfs/tree-log.c    | 32 +++++++++++++++++++-------------
 4 files changed, 24 insertions(+), 16 deletions(-)

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 34a60a8..745e7ad 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -1285,7 +1285,7 @@ struct btrfs_fs_info {
 	 * this is updated to the current trans every time a full commit
 	 * is required instead of the faster short fsync log commits
 	 */
-	u64 last_trans_log_full_commit;
+	atomic64_t last_trans_log_full_commit;
 	unsigned long mount_opt;
 	unsigned long compress_type:4;
 	u64 max_inline;
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 2d9fe27..a302e3a 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -7894,7 +7894,8 @@ int btrfs_make_block_group(struct btrfs_trans_handle
*trans,
 
 	extent_root = root->fs_info->extent_root;
 
-	root->fs_info->last_trans_log_full_commit = trans->transid;
+	atomic64_set(&root->fs_info->last_trans_log_full_commit,
+		     trans->transid);
 
 	cache = kzalloc(sizeof(*cache), GFP_NOFS);
 	if (!cache)
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index aadb0db..fb70bcb 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -7396,7 +7396,8 @@ static int btrfs_rename(struct inode *old_dir, struct
dentry *old_dentry,
 
 	if (unlikely(old_ino == BTRFS_FIRST_FREE_OBJECTID)) {
 		/* force full log commit if subvolume involved. */
-		root->fs_info->last_trans_log_full_commit = trans->transid;
+		atomic64_set(&root->fs_info->last_trans_log_full_commit,
+			     trans->transid);
 	} else {
 		ret = btrfs_insert_inode_ref(trans, dest,
 					     new_dentry->d_name.name,
diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c
index e6c8eb2..f352531 100644
--- a/fs/btrfs/tree-log.c
+++ b/fs/btrfs/tree-log.c
@@ -2227,14 +2227,14 @@ static int wait_log_commit(struct btrfs_trans_handle
*trans,
 				&wait, TASK_UNINTERRUPTIBLE);
 		mutex_unlock(&root->log_mutex);
 
-		if (root->fs_info->last_trans_log_full_commit !+		if
(atomic64_read(&root->fs_info->last_trans_log_full_commit) ! 		   
trans->transid && root->log_transid < transid + 2 &&
 		    atomic_read(&root->log_commit[index]))
 			schedule();
 
 		finish_wait(&root->log_commit_wait[index], &wait);
 		mutex_lock(&root->log_mutex);
-	} while (root->fs_info->last_trans_log_full_commit !+	} while
(atomic64_read(&root->fs_info->last_trans_log_full_commit) ! 		
trans->transid && root->log_transid < transid + 2 &&
 		 atomic_read(&root->log_commit[index]));
 	return 0;
@@ -2244,12 +2244,12 @@ static void wait_for_writer(struct btrfs_trans_handle
*trans,
 			    struct btrfs_root *root)
 {
 	DEFINE_WAIT(wait);
-	while (root->fs_info->last_trans_log_full_commit !+	while
(atomic64_read(&root->fs_info->last_trans_log_full_commit) ! 	      
trans->transid && atomic_read(&root->log_writers)) {
 		prepare_to_wait(&root->log_writer_wait,
 				&wait, TASK_UNINTERRUPTIBLE);
 		mutex_unlock(&root->log_mutex);
-		if (root->fs_info->last_trans_log_full_commit !+		if
(atomic64_read(&root->fs_info->last_trans_log_full_commit) ! 		   
trans->transid && atomic_read(&root->log_writers))
 			schedule();
 		mutex_lock(&root->log_mutex);
@@ -2306,7 +2306,8 @@ int btrfs_sync_log(struct btrfs_trans_handle *trans,
 	}
 
 	/* bail out if we need to do a full commit */
-	if (root->fs_info->last_trans_log_full_commit == trans->transid) {
+	if (atomic64_read(&root->fs_info->last_trans_log_full_commit) =+	   
trans->transid) {
 		ret = -EAGAIN;
 		mutex_unlock(&root->log_mutex);
 		goto out;
@@ -2361,7 +2362,8 @@ int btrfs_sync_log(struct btrfs_trans_handle *trans,
 			mutex_unlock(&log_root_tree->log_mutex);
 			goto out;
 		}
-		root->fs_info->last_trans_log_full_commit = trans->transid;
+		atomic64_set(&root->fs_info->last_trans_log_full_commit,
+			     trans->transid);
 		btrfs_wait_marked_extents(log, &log->dirty_log_pages, mark);
 		mutex_unlock(&log_root_tree->log_mutex);
 		ret = -EAGAIN;
@@ -2390,7 +2392,8 @@ int btrfs_sync_log(struct btrfs_trans_handle *trans,
 	 * now that we''ve moved on to the tree of log tree roots,
 	 * check the full commit flag again
 	 */
-	if (root->fs_info->last_trans_log_full_commit == trans->transid) {
+	if (atomic64_read(&root->fs_info->last_trans_log_full_commit) =+	   
trans->transid) {
 		btrfs_wait_marked_extents(log, &log->dirty_log_pages, mark);
 		mutex_unlock(&log_root_tree->log_mutex);
 		ret = -EAGAIN;
@@ -2614,7 +2617,8 @@ fail:
 out_unlock:
 	mutex_unlock(&BTRFS_I(dir)->log_mutex);
 	if (ret == -ENOSPC) {
-		root->fs_info->last_trans_log_full_commit = trans->transid;
+		atomic64_set(&root->fs_info->last_trans_log_full_commit,
+			     trans->transid);
 		ret = 0;
 	} else if (ret < 0)
 		btrfs_abort_transaction(trans, root, ret);
@@ -2647,7 +2651,8 @@ int btrfs_del_inode_ref_in_log(struct btrfs_trans_handle
*trans,
 				  dirid, &index);
 	mutex_unlock(&BTRFS_I(inode)->log_mutex);
 	if (ret == -ENOSPC) {
-		root->fs_info->last_trans_log_full_commit = trans->transid;
+		atomic64_set(&root->fs_info->last_trans_log_full_commit,
+			     trans->transid);
 		ret = 0;
 	} else if (ret < 0 && ret != -ENOENT)
 		btrfs_abort_transaction(trans, root, ret);
@@ -3702,8 +3707,8 @@ static noinline int check_parent_dirs_for_sync(struct
btrfs_trans_handle *trans,
 			 * make sure any commits to the log are forced
 			 * to be full commits
 			 */
-			root->fs_info->last_trans_log_full_commit -				trans->transid;
+			atomic64_set(&root->fs_info->last_trans_log_full_commit,
+				trans->transid);
 			ret = 1;
 			break;
 		}
@@ -3749,7 +3754,7 @@ int btrfs_log_inode_parent(struct btrfs_trans_handle
*trans,
 		goto end_no_trans;
 	}
 
-	if (root->fs_info->last_trans_log_full_commit >
+	if (atomic64_read(&root->fs_info->last_trans_log_full_commit) >
 	    atomic64_read(&root->fs_info->last_trans_committed)) {
 		ret = 1;
 		goto end_no_trans;
@@ -3819,7 +3824,8 @@ end_trans:
 	dput(old_parent);
 	if (ret < 0) {
 		WARN_ON(ret != -ENOSPC);
-		root->fs_info->last_trans_log_full_commit = trans->transid;
+		atomic64_set(&root->fs_info->last_trans_log_full_commit,
+			     trans->transid);
 		ret = 1;
 	}
 	btrfs_end_log_trans(root);
-- 
1.7.11.7
--
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