ext4: add optimization for the lazytime mount option

Add an optimization for the MS_LAZYTIME mount option so that we will
opportunistically write out any inodes with the I_DIRTY_TIME flag set
in a particular inode table block when we need to update some inode in
that inode table block anyway.

Also add some temporary code so that we can set the lazytime mount
option without needing a modified /sbin/mount program which can set
MS_LAZYTIME.  We can eventually make this go away once util-linux has
added support.

Google-Bug-Id: 18297052

Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 30 insertions, 0 deletions

diff --git a/include/trace/events/ext4.h b/include/trace/events/ext4.h
index 6cfb841fea7c..6e5abd6d38a2 100644
--- a/include/trace/events/ext4.h
+++ b/include/trace/events/ext4.h
@@ -73,6 +73,36 @@ struct extent_status;
         { FALLOC_FL_ZERO_RANGE,         "ZERO_RANGE"})
 
 
+TRACE_EVENT(ext4_other_inode_update_time,
+        TP_PROTO(struct inode *inode, ino_t orig_ino),
+
+        TP_ARGS(inode, orig_ino),
+
+        TP_STRUCT__entry(
+                __field(        dev_t,  dev                     )
+                __field(        ino_t,  ino                     )
+                __field(        ino_t,  orig_ino                )
+                __field(        uid_t,  uid                     )
+                __field(        gid_t,  gid                     )
+                __field(        __u16, mode                     )
+        ),
+
+        TP_fast_assign(
+                __entry->orig_ino = orig_ino;
+                __entry->dev    = inode->i_sb->s_dev;
+                __entry->ino    = inode->i_ino;
+                __entry->uid    = i_uid_read(inode);
+                __entry->gid    = i_gid_read(inode);
+                __entry->mode   = inode->i_mode;
+        ),
+
+        TP_printk("dev %d,%d orig_ino %lu ino %lu mode 0%o uid %u gid %u",
+                  MAJOR(__entry->dev), MINOR(__entry->dev),
+                  (unsigned long) __entry->orig_ino,
+                  (unsigned long) __entry->ino, __entry->mode,
+                  __entry->uid, __entry->gid)
+);
+
 TRACE_EVENT(ext4_free_inode,
         TP_PROTO(struct inode *inode),