3 files changed, 102 insertions, 2 deletions

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 628df5ba44a6..9193ea130dcb 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -4139,6 +4139,65 @@ static int ext4_inode_blocks_set(handle_t *handle,
         return 0;
 }
 
+struct other_inode {
+        unsigned long           orig_ino;
+        struct ext4_inode       *raw_inode;
+};
+
+static int other_inode_match(struct inode * inode, unsigned long ino,
+                             void *data)
+{
+        struct other_inode *oi = (struct other_inode *) data;
+
+        if ((inode->i_ino != ino) ||
+            (inode->i_state & (I_FREEING | I_WILL_FREE | I_NEW |
+                               I_DIRTY_SYNC | I_DIRTY_DATASYNC)) ||
+            ((inode->i_state & I_DIRTY_TIME) == 0))
+                return 0;
+        spin_lock(&inode->i_lock);
+        if (((inode->i_state & (I_FREEING | I_WILL_FREE | I_NEW |
+                                I_DIRTY_SYNC | I_DIRTY_DATASYNC)) == 0) &&
+            (inode->i_state & I_DIRTY_TIME)) {
+                struct ext4_inode_info  *ei = EXT4_I(inode);
+
+                inode->i_state &= ~(I_DIRTY_TIME | I_DIRTY_TIME_EXPIRED);
+                spin_unlock(&inode->i_lock);
+
+                spin_lock(&ei->i_raw_lock);
+                EXT4_INODE_SET_XTIME(i_ctime, inode, oi->raw_inode);
+                EXT4_INODE_SET_XTIME(i_mtime, inode, oi->raw_inode);
+                EXT4_INODE_SET_XTIME(i_atime, inode, oi->raw_inode);
+                ext4_inode_csum_set(inode, oi->raw_inode, ei);
+                spin_unlock(&ei->i_raw_lock);
+                trace_ext4_other_inode_update_time(inode, oi->orig_ino);
+                return -1;
+        }
+        spin_unlock(&inode->i_lock);
+        return -1;
+}
+
+/*
+ * Opportunistically update the other time fields for other inodes in
+ * the same inode table block.
+ */
+static void ext4_update_other_inodes_time(struct super_block *sb,
+                                          unsigned long orig_ino, char *buf)
+{
+        struct other_inode oi;
+        unsigned long ino;
+        int i, inodes_per_block = EXT4_SB(sb)->s_inodes_per_block;
+        int inode_size = EXT4_INODE_SIZE(sb);
+
+        oi.orig_ino = orig_ino;
+        ino = orig_ino & ~(inodes_per_block - 1);
+        for (i = 0; i < inodes_per_block; i++, ino++, buf += inode_size) {
+                if (ino == orig_ino)
+                        continue;
+                oi.raw_inode = (struct ext4_inode *) buf;
+                (void) find_inode_nowait(sb, ino, other_inode_match, &oi);
+        }
+}
+
 /*
  * Post the struct inode info into an on-disk inode location in the
  * buffer-cache.  This gobbles the caller's reference to the
@@ -4248,10 +4307,11 @@ static int ext4_do_update_inode(handle_t *handle,
                                 cpu_to_le16(ei->i_extra_isize);
                 }
         }
-
         ext4_inode_csum_set(inode, raw_inode, ei);
-
         spin_unlock(&ei->i_raw_lock);
+        if (inode->i_sb->s_flags & MS_LAZYTIME)
+                ext4_update_other_inodes_time(inode->i_sb, inode->i_ino,
+                                              bh->b_data);
 
         BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
         rc = ext4_handle_dirty_metadata(handle, NULL, bh);
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 74c5f53595fb..362b23c8497a 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -1139,6 +1139,7 @@ enum {
         Opt_noquota, Opt_barrier, Opt_nobarrier, Opt_err,
         Opt_usrquota, Opt_grpquota, Opt_i_version,
         Opt_stripe, Opt_delalloc, Opt_nodelalloc, Opt_mblk_io_submit,
+        Opt_lazytime, Opt_nolazytime,
         Opt_nomblk_io_submit, Opt_block_validity, Opt_noblock_validity,
         Opt_inode_readahead_blks, Opt_journal_ioprio,
         Opt_dioread_nolock, Opt_dioread_lock,
@@ -1202,6 +1203,8 @@ static const match_table_t tokens = {
         {Opt_i_version, "i_version"},
         {Opt_stripe, "stripe=%u"},
         {Opt_delalloc, "delalloc"},
+        {Opt_lazytime, "lazytime"},
+        {Opt_nolazytime, "nolazytime"},
         {Opt_nodelalloc, "nodelalloc"},
         {Opt_removed, "mblk_io_submit"},
         {Opt_removed, "nomblk_io_submit"},
@@ -1459,6 +1462,12 @@ static int handle_mount_opt(struct super_block *sb, char *opt, int token,
         case Opt_i_version:
                 sb->s_flags |= MS_I_VERSION;
                 return 1;
+        case Opt_lazytime:
+                sb->s_flags |= MS_LAZYTIME;
+                return 1;
+        case Opt_nolazytime:
+                sb->s_flags &= ~MS_LAZYTIME;
+                return 1;
         }
 
         for (m = ext4_mount_opts; m->token != Opt_err; m++)
@@ -5020,6 +5029,7 @@ static int ext4_remount(struct super_block *sb, int *flags, char *data)
         }
 #endif
 
+        *flags = (*flags & ~MS_LAZYTIME) | (sb->s_flags & MS_LAZYTIME);
         ext4_msg(sb, KERN_INFO, "re-mounted. Opts: %s", orig_data);
         kfree(orig_data);
         return 0;
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),