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jffs2: get rid of jffs2_sync_super

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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 a delayed work. Instead of setting the 's_dirt'
flag we just schedule a delayed work for synchronizing the write-buffer.

Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Artem Bityutskiy 2012-05-07 19:56:53 +03:00 committed by Al Viro
parent 06688905cc
commit 8bdc81c506
4 changed files with 58 additions and 21 deletions
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4
fs/jffs2/jffs2_fs_sb.h
View File

@ -126,6 +126,10 @@ struct jffs2_sb_info {
struct jffs2_inodirty *wbuf_inodes;
struct rw_semaphore wbuf_sem; /* Protects the write buffer */
struct delayed_work wbuf_dwork; /* write-buffer write-out work */
int wbuf_queued; /* non-zero delayed work is queued */
spinlock_t wbuf_dwork_lock; /* protects wbuf_dwork and and wbuf_queued */
unsigned char *oobbuf;
int oobavail; /* How many bytes are available for JFFS2 in OOB */
#endif

7
fs/jffs2/os-linux.h
View File

@ -95,6 +95,7 @@ static inline void jffs2_init_inode_info(struct jffs2_inode_info *f)
#define jffs2_ubivol(c) (0)
#define jffs2_ubivol_setup(c) (0)
#define jffs2_ubivol_cleanup(c) do {} while (0)
#define jffs2_dirty_trigger(c) do {} while (0)
#else /* NAND and/or ECC'd NOR support present */
@ -135,14 +136,10 @@ void jffs2_ubivol_cleanup(struct jffs2_sb_info *c);
#define jffs2_nor_wbuf_flash(c) (c->mtd->type == MTD_NORFLASH && ! (c->mtd->flags & MTD_BIT_WRITEABLE))
int jffs2_nor_wbuf_flash_setup(struct jffs2_sb_info *c);
void jffs2_nor_wbuf_flash_cleanup(struct jffs2_sb_info *c);
void jffs2_dirty_trigger(struct jffs2_sb_info *c);
#endif /* WRITEBUFFER */
static inline void jffs2_dirty_trigger(struct jffs2_sb_info *c)
{
OFNI_BS_2SFFJ(c)->s_dirt = 1;
}
/* background.c */
int jffs2_start_garbage_collect_thread(struct jffs2_sb_info *c);
void jffs2_stop_garbage_collect_thread(struct jffs2_sb_info *c);

13
fs/jffs2/super.c
View File

@ -63,18 +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);
sb->s_dirt = 0;
if (!(sb->s_flags & MS_RDONLY)) {
jffs2_dbg(1, "%s()\n", __func__);
jffs2_flush_wbuf_gc(c, 0);
}
}
static const char *jffs2_compr_name(unsigned int compr)
{
switch (compr) {
@ -246,7 +234,6 @@ static const struct super_operations jffs2_super_operations =
.alloc_inode = jffs2_alloc_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,

55
fs/jffs2/wbuf.c
View File

@ -20,6 +20,7 @@
#include <linux/mtd/nand.h>
#include <linux/jiffies.h>
#include <linux/sched.h>
#include <linux/writeback.h>
#include "nodelist.h"
@ -85,7 +86,7 @@ static void jffs2_wbuf_dirties_inode(struct jffs2_sb_info *c, uint32_t ino)
{
struct jffs2_inodirty *new;
/* Mark the superblock dirty so that kupdated will flush... */
/* Schedule delayed write-buffer write-out */
jffs2_dirty_trigger(c);
if (jffs2_wbuf_pending_for_ino(c, ino))
@ -1148,6 +1149,47 @@ int jffs2_write_nand_badblock(struct jffs2_sb_info *c, struct jffs2_eraseblock *
return 1;
}
static struct jffs2_sb_info *work_to_sb(struct work_struct *work)
{
struct delayed_work *dwork;
dwork = container_of(work, struct delayed_work, work);
return container_of(dwork, struct jffs2_sb_info, wbuf_dwork);
}
static void delayed_wbuf_sync(struct work_struct *work)
{
struct jffs2_sb_info *c = work_to_sb(work);
struct super_block *sb = OFNI_BS_2SFFJ(c);
spin_lock(&c->wbuf_dwork_lock);
c->wbuf_queued = 0;
spin_unlock(&c->wbuf_dwork_lock);
if (!(sb->s_flags & MS_RDONLY)) {
jffs2_dbg(1, "%s()\n", __func__);
jffs2_flush_wbuf_gc(c, 0);
}
}
void jffs2_dirty_trigger(struct jffs2_sb_info *c)
{
struct super_block *sb = OFNI_BS_2SFFJ(c);
unsigned long delay;
if (sb->s_flags & MS_RDONLY)
return;
spin_lock(&c->wbuf_dwork_lock);
if (!c->wbuf_queued) {
jffs2_dbg(1, "%s()\n", __func__);
delay = msecs_to_jiffies(dirty_writeback_interval * 10);
queue_delayed_work(system_long_wq, &c->wbuf_dwork, delay);
c->wbuf_queued = 1;
}
spin_unlock(&c->wbuf_dwork_lock);
}
int jffs2_nand_flash_setup(struct jffs2_sb_info *c)
{
struct nand_ecclayout *oinfo = c->mtd->ecclayout;
@ -1169,6 +1211,8 @@ int jffs2_nand_flash_setup(struct jffs2_sb_info *c)
/* Initialise write buffer */
init_rwsem(&c->wbuf_sem);
spin_lock_init(&c->wbuf_dwork_lock);
INIT_DELAYED_WORK(&c->wbuf_dwork, delayed_wbuf_sync);
c->wbuf_pagesize = c->mtd->writesize;
c->wbuf_ofs = 0xFFFFFFFF;
@ -1207,8 +1251,8 @@ int jffs2_dataflash_setup(struct jffs2_sb_info *c) {
/* Initialize write buffer */
init_rwsem(&c->wbuf_sem);
spin_lock_init(&c->wbuf_dwork_lock);
INIT_DELAYED_WORK(&c->wbuf_dwork, delayed_wbuf_sync);
c->wbuf_pagesize = c->mtd->erasesize;
/* Find a suitable c->sector_size
@ -1267,6 +1311,9 @@ int jffs2_nor_wbuf_flash_setup(struct jffs2_sb_info *c) {
/* Initialize write buffer */
init_rwsem(&c->wbuf_sem);
spin_lock_init(&c->wbuf_dwork_lock);
INIT_DELAYED_WORK(&c->wbuf_dwork, delayed_wbuf_sync);
c->wbuf_pagesize = c->mtd->writesize;
c->wbuf_ofs = 0xFFFFFFFF;
@ -1299,6 +1346,8 @@ int jffs2_ubivol_setup(struct jffs2_sb_info *c) {
return 0;
init_rwsem(&c->wbuf_sem);
spin_lock_init(&c->wbuf_dwork_lock);
INIT_DELAYED_WORK(&c->wbuf_dwork, delayed_wbuf_sync);
c->wbuf_pagesize = c->mtd->writesize;
c->wbuf_ofs = 0xFFFFFFFF;