Add O_SYNC support to btrfs_file_write

Signed-off-by: Chris Mason <chris.mason@oracle.com>

diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index 9260d3478aadbf6665a8576fe96d416b3e5ebcd1..843e920388edd2507ea5183888be92edef1e17d5 100644 (file)
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -635,8 +635,9 @@ static ssize_t btrfs_file_write(struct file *file, const char __user *buf,
                                size_t count, loff_t *ppos)
 {
        loff_t pos;
-       size_t num_written = 0;
-       int err = 0;
+       loff_t start_pos;
+       ssize_t num_written = 0;
+       ssize_t err = 0;
        int ret = 0;
        struct inode *inode = file->f_path.dentry->d_inode;
        struct btrfs_root *root = BTRFS_I(inode)->root;
@@ -652,7 +653,10 @@ static ssize_t btrfs_file_write(struct file *file, const char __user *buf,
        pinned[1] = NULL;
        if (file->f_flags & O_DIRECT)
                return -EINVAL;
+
        pos = *ppos;
+       start_pos = pos;
+
        vfs_check_frozen(inode->i_sb, SB_FREEZE_WRITE);
        current->backing_dev_info = inode->i_mapping->backing_dev_info;
        err = generic_write_checks(file, &pos, &count, S_ISBLK(inode->i_mode));
@@ -743,6 +747,13 @@ out:
        if (pinned[1])
                page_cache_release(pinned[1]);
        *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);
+               if (err < 0)
+                       num_written = err;
+       }
        current->backing_dev_info = NULL;
        return num_written ? num_written : err;
 }