Add O_SYNC support to btrfs_file_write

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

1 files changed, 13 insertions, 2 deletions

diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index 9260d3478aad..843e920388ed 100644
--- 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;
 }