xfs: refactor xfs_file_fsync

Factor out the log syncing logic into two helpers to make the code easier
to read and more maintainable.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>

diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
index 4927c6653f15d9efea7cb4bad7af2e15b169640d..9441c257d86cc877fba908861ccf2fee7ff4ca8b 100644 (file)
--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c
@@ -118,6 +118,54 @@ xfs_dir_fsync(
        return xfs_log_force_inode(ip);
 }
 
+static xfs_lsn_t
+xfs_fsync_lsn(
+       struct xfs_inode        *ip,
+       bool                    datasync)
+{
+       if (!xfs_ipincount(ip))
+               return 0;
+       if (datasync && !(ip->i_itemp->ili_fsync_fields & ~XFS_ILOG_TIMESTAMP))
+               return 0;
+       return ip->i_itemp->ili_last_lsn;
+}
+
+/*
+ * All metadata updates are logged, which means that we just have to flush the
+ * log up to the latest LSN that touched the inode.
+ *
+ * If we have concurrent fsync/fdatasync() calls, we need them to all block on
+ * the log force before we clear the ili_fsync_fields field. This ensures that
+ * we don't get a racing sync operation that does not wait for the metadata to
+ * hit the journal before returning.  If we race with clearing ili_fsync_fields,
+ * then all that will happen is the log force will do nothing as the lsn will
+ * already be on disk.  We can't race with setting ili_fsync_fields because that
+ * is done under XFS_ILOCK_EXCL, and that can't happen because we hold the lock
+ * shared until after the ili_fsync_fields is cleared.
+ */
+static  int
+xfs_fsync_flush_log(
+       struct xfs_inode        *ip,
+       bool                    datasync,
+       int                     *log_flushed)
+{
+       int                     error = 0;
+       xfs_lsn_t               lsn;
+
+       xfs_ilock(ip, XFS_ILOCK_SHARED);
+       lsn = xfs_fsync_lsn(ip, datasync);
+       if (lsn) {
+               error = xfs_log_force_lsn(ip->i_mount, lsn, XFS_LOG_SYNC,
+                                         log_flushed);
+
+               spin_lock(&ip->i_itemp->ili_lock);
+               ip->i_itemp->ili_fsync_fields = 0;
+               spin_unlock(&ip->i_itemp->ili_lock);
+       }
+       xfs_iunlock(ip, XFS_ILOCK_SHARED);
+       return error;
+}
+
 STATIC int
 xfs_file_fsync(
        struct file             *file,
@@ -125,13 +173,10 @@ xfs_file_fsync(
        loff_t                  end,
        int                     datasync)
 {
-       struct inode            *inode = file->f_mapping->host;
-       struct xfs_inode        *ip = XFS_I(inode);
-       struct xfs_inode_log_item *iip = ip->i_itemp;
+       struct xfs_inode        *ip = XFS_I(file->f_mapping->host);
        struct xfs_mount        *mp = ip->i_mount;
        int                     error = 0;
        int                     log_flushed = 0;
-       xfs_lsn_t               lsn = 0;
 
        trace_xfs_file_fsync(ip);
 
@@ -155,33 +200,7 @@ xfs_file_fsync(
        else if (mp->m_logdev_targp != mp->m_ddev_targp)
                xfs_blkdev_issue_flush(mp->m_ddev_targp);
 
-       /*
-        * All metadata updates are logged, which means that we just have to
-        * flush the log up to the latest LSN that touched the inode. If we have
-        * concurrent fsync/fdatasync() calls, we need them to all block on the
-        * log force before we clear the ili_fsync_fields field. This ensures
-        * that we don't get a racing sync operation that does not wait for the
-        * metadata to hit the journal before returning. If we race with
-        * clearing the ili_fsync_fields, then all that will happen is the log
-        * force will do nothing as the lsn will already be on disk. We can't
-        * race with setting ili_fsync_fields because that is done under
-        * XFS_ILOCK_EXCL, and that can't happen because we hold the lock shared
-        * until after the ili_fsync_fields is cleared.
-        */
-       xfs_ilock(ip, XFS_ILOCK_SHARED);
-       if (xfs_ipincount(ip)) {
-               if (!datasync ||
-                   (iip->ili_fsync_fields & ~XFS_ILOG_TIMESTAMP))
-                       lsn = iip->ili_last_lsn;
-       }
-
-       if (lsn) {
-               error = xfs_log_force_lsn(mp, lsn, XFS_LOG_SYNC, &log_flushed);
-               spin_lock(&iip->ili_lock);
-               iip->ili_fsync_fields = 0;
-               spin_unlock(&iip->ili_lock);
-       }
-       xfs_iunlock(ip, XFS_ILOCK_SHARED);
+       error = xfs_fsync_flush_log(ip, datasync, &log_flushed);
 
        /*
         * If we only have a single device, and the log force about was