Btrfs: Add a write ahead tree log to optimize synchronous operations

[linux-2.6-block.git] / fs / btrfs / file.c

diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index e9e86fbaa243521427b9955893e3b06663a7da93..84ecf3ab8511e04423cf44fc2811b6608bacd922 100644 (file)
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -36,6 +36,8 @@
 #include "btrfs_inode.h"
 #include "ioctl.h"
 #include "print-tree.h"
+#include "tree-log.h"
+#include "locking.h"
 #include "compat.h"
 
 
@@ -988,10 +990,27 @@ out_nolock:
        *ppos = pos;
 
        if (num_written > 0 && ((file->f_flags & O_SYNC) || IS_SYNC(inode))) {
-               err = sync_page_range(inode, inode->i_mapping,
-                                     start_pos, num_written);
+               struct btrfs_trans_handle *trans;
+
+               err = btrfs_fdatawrite_range(inode->i_mapping, start_pos,
+                                            start_pos + num_written -1,
+                                            WB_SYNC_NONE);
+               if (err < 0)
+                       num_written = err;
+
+               err = btrfs_wait_on_page_writeback_range(inode->i_mapping,
+                                start_pos, start_pos + num_written - 1);
                if (err < 0)
                        num_written = err;
+
+               trans = btrfs_start_transaction(root, 1);
+               ret = btrfs_log_dentry_safe(trans, root, file->f_dentry);
+               if (ret == 0) {
+                       btrfs_sync_log(trans, root);
+                       btrfs_end_transaction(trans, root);
+               } else {
+                       btrfs_commit_transaction(trans, root);
+               }
        } else if (num_written > 0 && (file->f_flags & O_DIRECT)) {
 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,22)
                do_sync_file_range(file, start_pos,
@@ -1019,8 +1038,7 @@ int btrfs_release_file(struct inode * inode, struct file * filp)
        return 0;
 }
 
-static int btrfs_sync_file(struct file *file,
-                          struct dentry *dentry, int datasync)
+int btrfs_sync_file(struct file *file, struct dentry *dentry, int datasync)
 {
        struct inode *inode = dentry->d_inode;
        struct btrfs_root *root = BTRFS_I(inode)->root;
@@ -1043,6 +1061,8 @@ static int btrfs_sync_file(struct file *file,
        }
        mutex_unlock(&root->fs_info->trans_mutex);
 
+       filemap_fdatawait(inode->i_mapping);
+
        /*
         * ok we haven't committed the transaction yet, lets do a commit
         */
@@ -1054,7 +1074,16 @@ static int btrfs_sync_file(struct file *file,
                ret = -ENOMEM;
                goto out;
        }
-       ret = btrfs_commit_transaction(trans, root);
+
+       ret = btrfs_log_dentry_safe(trans, root, file->f_dentry);
+       if (ret < 0)
+               goto out;
+       if (ret > 0) {
+               ret = btrfs_commit_transaction(trans, root);
+       } else {
+               btrfs_sync_log(trans, root);
+               ret = btrfs_end_transaction(trans, root);
+       }
 out:
        return ret > 0 ? EIO : ret;
 }