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Message-Id: <1336152428-24242-3-git-send-email-dedekind1@gmail.com>
Date: Fri, 4 May 2012 20:27:08 +0300
From: Artem Bityutskiy <dedekind1@...il.com>
To: David Woodhouse <dwmw2@...radead.org>,
MTD Maling List <linux-mtd@...ts.infradead.org>
Cc: Linux Kernel Maling List <linux-kernel@...r.kernel.org>,
Artem Bityutskiy <artem.bityutskiy@...ux.intel.com>
Subject: [PATCH 2/2] jffs2: get rid of jffs2_sync_super
From: Artem Bityutskiy <artem.bityutskiy@...ux.intel.com>
Currently JFFS2 file-system maps the VFS "superblock" abstraction to the
write-buffer. Namely, it uses VFS services to synchronize the write-buffer
periodically.
The whole "superblock write-out" VFS infrastructure is served by the
'sync_supers()' kernel thread, which wakes up every 5 (by default) seconds and
writes out all dirty superblock using the '->write_super()' call-back. But the
problem with this thread is that it wastes power by waking up the system every
5 seconds no matter what. So we want to kill it completely and thus, we need to
make file-systems to stop using the '->write_super' VFS service, and then
remove it together with the kernel thread.
This patch switches the JFFS2 write-buffer management from
'->write_super()'/'->s_dirt' to 'wbuf_inode'/'->write_inode'. Instead of
setting the 's_dirt' flag, we just mark the special 'wbuf_inode' inode as
dirty and let VFS invoke the '->write_inode' call-back when needed, where we
synchronize the write-buffer.
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@...ux.intel.com>
---
fs/jffs2/fs.c | 18 ++++++++++++++++++
fs/jffs2/os-linux.h | 3 ++-
fs/jffs2/super.c | 22 +---------------------
3 files changed, 21 insertions(+), 22 deletions(-)
diff --git a/fs/jffs2/fs.c b/fs/jffs2/fs.c
index 94016a9..c6aacbb 100644
--- a/fs/jffs2/fs.c
+++ b/fs/jffs2/fs.c
@@ -228,6 +228,24 @@ int jffs2_statfs(struct dentry *dentry, struct kstatfs *buf)
return 0;
}
+int jffs2_write_inode(struct inode *inode, struct writeback_control *wbc)
+{
+ struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
+
+ /*
+ * JFFS2 is synchronous file-system, and the only the fake write-buffer
+ * inode is allowed to be writen-out asynchronously - we use this to do
+ * delayed write-buffer synchronization.
+ */
+ BUG_ON(inode != c->wbuf_inode);
+
+ if (!(inode->i_sb->s_flags & MS_RDONLY)) {
+ jffs2_dbg(1, "%s()\n", __func__);
+ jffs2_flush_wbuf_gc(c, 0);
+ }
+
+ return 0;
+}
void jffs2_evict_inode (struct inode *inode)
{
diff --git a/fs/jffs2/os-linux.h b/fs/jffs2/os-linux.h
index 6f28cc5..ab97e88 100644
--- a/fs/jffs2/os-linux.h
+++ b/fs/jffs2/os-linux.h
@@ -144,7 +144,7 @@ void jffs2_nor_wbuf_flash_cleanup(struct jffs2_sb_info *c);
static inline void jffs2_dirty_trigger(struct jffs2_sb_info *c)
{
- OFNI_BS_2SFFJ(c)->s_dirt = 1;
+ __mark_inode_dirty(c->wbuf_inode, I_DIRTY_SYNC);
}
/* background.c */
@@ -173,6 +173,7 @@ extern const struct inode_operations jffs2_symlink_inode_operations;
int jffs2_setattr (struct dentry *, struct iattr *);
int jffs2_do_setattr (struct inode *, struct iattr *);
struct inode *jffs2_iget(struct super_block *, unsigned long);
+int jffs2_write_inode(struct inode *inode, struct writeback_control *wbc);
void jffs2_evict_inode (struct inode *);
void jffs2_dirty_inode(struct inode *inode, int flags);
struct inode *jffs2_new_inode (struct inode *dir_i, umode_t mode,
diff --git a/fs/jffs2/super.c b/fs/jffs2/super.c
index a180409..0b4e632 100644
--- a/fs/jffs2/super.c
+++ b/fs/jffs2/super.c
@@ -63,21 +63,6 @@ static void jffs2_i_init_once(void *foo)
inode_init_once(&f->vfs_inode);
}
-static void jffs2_write_super(struct super_block *sb)
-{
- struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
-
- lock_super(sb);
- sb->s_dirt = 0;
-
- if (!(sb->s_flags & MS_RDONLY)) {
- jffs2_dbg(1, "%s()\n", __func__);
- jffs2_flush_wbuf_gc(c, 0);
- }
-
- unlock_super(sb);
-}
-
static const char *jffs2_compr_name(unsigned int compr)
{
switch (compr) {
@@ -113,8 +98,6 @@ static int jffs2_sync_fs(struct super_block *sb, int wait)
{
struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
- jffs2_write_super(sb);
-
mutex_lock(&c->alloc_sem);
jffs2_flush_wbuf_pad(c);
mutex_unlock(&c->alloc_sem);
@@ -249,9 +232,9 @@ static int jffs2_remount_fs(struct super_block *sb, int *flags, char *data)
static const struct super_operations jffs2_super_operations =
{
.alloc_inode = jffs2_alloc_inode,
+ .write_inode = jffs2_write_inode,
.destroy_inode =jffs2_destroy_inode,
.put_super = jffs2_put_super,
- .write_super = jffs2_write_super,
.statfs = jffs2_statfs,
.remount_fs = jffs2_remount_fs,
.evict_inode = jffs2_evict_inode,
@@ -319,9 +302,6 @@ static void jffs2_put_super (struct super_block *sb)
jffs2_dbg(2, "%s()\n", __func__);
- if (sb->s_dirt)
- jffs2_write_super(sb);
-
mutex_lock(&c->alloc_sem);
jffs2_flush_wbuf_pad(c);
mutex_unlock(&c->alloc_sem);
--
1.7.7.6
--
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