[XFS] Fix remount,readonly path to flush everything correctly.

The remount readonly path can fail to writeback properly because we still
have active transactions after calling xfs_quiesce_fs(). Further
investigation shows that this path is broken in the same ways that the xfs
freeze path was broken so fix it the same way.

SGI-PV: 964464
SGI-Modid: xfs-linux-melb:xfs-kern:28869a

Signed-off-by: David Chinner <dgc@sgi.com>
Signed-off-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Tim Shimmin <tes@sgi.com>

1 files changed, 14 insertions, 0 deletions

diff --git a/fs/xfs/linux-2.6/xfs_vfs.h b/fs/xfs/linux-2.6/xfs_vfs.h
index cb7b0d62fb96..dca3481aaafa 100644
--- a/fs/xfs/linux-2.6/xfs_vfs.h
+++ b/fs/xfs/linux-2.6/xfs_vfs.h
@@ -94,6 +94,20 @@ typedef enum {
 #define SYNC_IOWAIT             0x0100  /* wait for all I/O to complete */
 #define SYNC_SUPER              0x0200  /* flush superblock to disk */
 
+/*
+ * When remounting a filesystem read-only or freezing the filesystem,
+ * we have two phases to execute. This first phase is syncing the data
+ * before we quiesce the fielsystem, and the second is flushing all the
+ * inodes out after we've waited for all the transactions created by
+ * the first phase to complete. The second phase uses SYNC_INODE_QUIESCE
+ * to ensure that the inodes are written to their location on disk
+ * rather than just existing in transactions in the log. This means
+ * after a quiesce there is no log replay required to write the inodes
+ * to disk (this is the main difference between a sync and a quiesce).
+ */
+#define SYNC_DATA_QUIESCE       (SYNC_DELWRI|SYNC_FSDATA|SYNC_WAIT|SYNC_IOWAIT)
+#define SYNC_INODE_QUIESCE      (SYNC_REMOUNT|SYNC_ATTR|SYNC_WAIT)
+
 #define SHUTDOWN_META_IO_ERROR  0x0001  /* write attempt to metadata failed */
 #define SHUTDOWN_LOG_IO_ERROR   0x0002  /* write attempt to the log failed */
 #define SHUTDOWN_FORCE_UMOUNT   0x0004  /* shutdown from a forced unmount */