ext4: add cleancache support

This seventh patch of eight in this cleancache series "opts-in"
cleancache for ext4.  Filesystems must explicitly enable cleancache
by calling cleancache_init_fs anytime an instance of the filesystem
is mounted. For ext4, all other cleancache hooks are in
the VFS layer including the matching cleancache_flush_fs
hook which must be called on unmount.

Details and a FAQ can be found in Documentation/vm/cleancache.txt

[v6-v8: no changes]
[v5: jeremy@goop.org: simplify init hook and any future fs init changes]
Signed-off-by: Dan Magenheimer <dan.magenheimer@oracle.com>
Reviewed-by: Jeremy Fitzhardinge <jeremy@goop.org>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Acked-by: Andreas Dilger <adilger@sun.com>
Cc: Ted Ts'o <tytso@mit.edu>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Matthew Wilcox <matthew@wil.cx>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Rik Van Riel <riel@redhat.com>
Cc: Jan Beulich <JBeulich@novell.com>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Joel Becker <joel.becker@oracle.com>
Cc: Nitin Gupta <ngupta@vflare.org>

diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 8553dfb310afd7ac2209d186125287e99a867f61..51476477c818e97d900c36bbd325f3dec44e40d0 100644 (file)
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -38,6 +38,7 @@
 #include <linux/ctype.h>
 #include <linux/log2.h>
 #include <linux/crc16.h>
+#include <linux/cleancache.h>
 #include <asm/uaccess.h>
 
 #include <linux/kthread.h>
@@ -1932,6 +1933,7 @@ static int ext4_setup_super(struct super_block *sb, struct ext4_super_block *es,
                        EXT4_INODES_PER_GROUP(sb),
                        sbi->s_mount_opt, sbi->s_mount_opt2);
 
+       cleancache_init_fs(sb);
        return res;
 }