Btrfs: fix unprotected ->log_batch

We forget to protect ->log_batch when syncing a file, this patch fix
this problem by atomic operation. And ->log_batch is used to check
if there are parallel sync operations or not, so it is unnecessary to
reset it to 0 after the sync operation of the current log tree complete.

Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 2990a7e..6923b9e 100644 (file)
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -1491,9 +1491,9 @@ struct btrfs_root {
        wait_queue_head_t log_commit_wait[2];
        atomic_t log_writers;
        atomic_t log_commit[2];
+       atomic_t log_batch;
        unsigned long log_transid;
        unsigned long last_log_commit;
-       unsigned long log_batch;
        pid_t log_start_pid;
        bool log_multiple_pids;
 

diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 0dcfb99..34717ac 100644 (file)
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -1168,8 +1168,8 @@ static void __setup_root(u32 nodesize, u32 leafsize, u32 sectorsize,
        atomic_set(&root->log_commit[0], 0);
        atomic_set(&root->log_commit[1], 0);
        atomic_set(&root->log_writers, 0);
+       atomic_set(&root->log_batch, 0);
        atomic_set(&root->orphan_inodes, 0);
-       root->log_batch = 0;
        root->log_transid = 0;
        root->last_log_commit = 0;
        extent_io_tree_init(&root->dirty_log_pages,

diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index a9d7815..793bc89 100644 (file)
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -1551,9 +1551,9 @@ int btrfs_sync_file(struct file *file, loff_t start, loff_t end, int datasync)
         * ordered range does a filemape_write_and_wait_range which is why we
         * don't do it above like other file systems.
         */
-       root->log_batch++;
+       atomic_inc(&root->log_batch);
        btrfs_wait_ordered_range(inode, start, end);
-       root->log_batch++;
+       atomic_inc(&root->log_batch);
 
        /*
         * check the transaction that last modified this inode

diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c
index f9b0fc9..038a522 100644 (file)
--- a/fs/btrfs/tree-log.c
+++ b/fs/btrfs/tree-log.c
@@ -147,7 +147,7 @@ static int start_log_trans(struct btrfs_trans_handle *trans,
                        root->log_multiple_pids = true;
                }
 
-               root->log_batch++;
+               atomic_inc(&root->log_batch);
                atomic_inc(&root->log_writers);
                mutex_unlock(&root->log_mutex);
                return 0;
@@ -166,7 +166,7 @@ static int start_log_trans(struct btrfs_trans_handle *trans,
                        err = ret;
        }
        mutex_unlock(&root->fs_info->tree_log_mutex);
-       root->log_batch++;
+       atomic_inc(&root->log_batch);
        atomic_inc(&root->log_writers);
        mutex_unlock(&root->log_mutex);
        return err;
@@ -2036,7 +2036,7 @@ int btrfs_sync_log(struct btrfs_trans_handle *trans,
        if (atomic_read(&root->log_commit[(index1 + 1) % 2]))
                wait_log_commit(trans, root, root->log_transid - 1);
        while (1) {
-               unsigned long batch = root->log_batch;
+               int batch = atomic_read(&root->log_batch);
                /* when we're on an ssd, just kick the log commit out */
                if (!btrfs_test_opt(root, SSD) && root->log_multiple_pids) {
                        mutex_unlock(&root->log_mutex);
@@ -2044,7 +2044,7 @@ int btrfs_sync_log(struct btrfs_trans_handle *trans,
                        mutex_lock(&root->log_mutex);
                }
                wait_for_writer(trans, root);
-               if (batch == root->log_batch)
+               if (batch == atomic_read(&root->log_batch))
                        break;
        }
 
@@ -2073,7 +2073,6 @@ int btrfs_sync_log(struct btrfs_trans_handle *trans,
 
        btrfs_set_root_node(&log->root_item, log->node);
 
-       root->log_batch = 0;
        root->log_transid++;
        log->log_transid = root->log_transid;
        root->log_start_pid = 0;
@@ -2086,7 +2085,7 @@ int btrfs_sync_log(struct btrfs_trans_handle *trans,
        mutex_unlock(&root->log_mutex);
 
        mutex_lock(&log_root_tree->log_mutex);
-       log_root_tree->log_batch++;
+       atomic_inc(&log_root_tree->log_batch);
        atomic_inc(&log_root_tree->log_writers);
        mutex_unlock(&log_root_tree->log_mutex);
 
@@ -2156,7 +2155,6 @@ int btrfs_sync_log(struct btrfs_trans_handle *trans,
        btrfs_set_super_log_root_level(root->fs_info->super_for_commit,
                                btrfs_header_level(log_root_tree->node));
 
-       log_root_tree->log_batch = 0;
        log_root_tree->log_transid++;
        smp_mb();