xfs: refactor unmount record write

Source kernel commit: 53235f22151ea7229e1251e46e68098bcf74922d

Refactor the writing of the unmount record into a separate helper.  No
functionality changes.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Eric Sandeen <sandeen@sandeen.net>

diff --git a/libxfs/xfs_log_format.h b/libxfs/xfs_log_format.h
index 79bb79853c9f1d4616547c05c3a1be83e639aa10..e5f97c69b3205e96c38b14b729fd10f3b42fff8a 100644 (file)
--- a/libxfs/xfs_log_format.h
+++ b/libxfs/xfs_log_format.h
@@ -77,6 +77,19 @@ static inline uint xlog_get_cycle(char *ptr)
 
 #define XLOG_UNMOUNT_TYPE      0x556e  /* Un for Unmount */
 
+/*
+ * Log item for unmount records.
+ *
+ * The unmount record used to have a string "Unmount filesystem--" in the
+ * data section where the "Un" was really a magic number (XLOG_UNMOUNT_TYPE).
+ * We just write the magic number now; see xfs_log_unmount_write.
+ */
+struct xfs_unmount_log_format {
+       uint16_t        magic;  /* XLOG_UNMOUNT_TYPE */
+       uint16_t        pad1;
+       uint32_t        pad2;   /* may as well make it 64 bits */
+};
+
 /* Region types for iovec's i_type */
 #define XLOG_REG_TYPE_BFORMAT          1
 #define XLOG_REG_TYPE_BCHUNK           2