reiserfs: get rid of resierfs_sync_super

This patch stops reiserfs using the VFS 'write_super()' method along with the
s_dirt flag, because they are on their way out.

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, even if there are no diry superblocks, or there are no client
file-systems which would need this (e.g., btrfs does not use
'->write_super()'). 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.

Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

diff --git a/fs/reiserfs/journal.c b/fs/reiserfs/journal.c
index e5e06dd8562f14a4e1c1c8b26a74708b301b1761..afcadcc03e8ac87c7f25f3e2393b3c108daaf91d 100644 (file)
--- a/fs/reiserfs/journal.c
+++ b/fs/reiserfs/journal.c
@@ -1923,6 +1923,8 @@ static int do_journal_release(struct reiserfs_transaction_handle *th,
         * the workqueue job (flush_async_commit) needs this lock
         */
        reiserfs_write_unlock(sb);
+
+       cancel_delayed_work_sync(&REISERFS_SB(sb)->old_work);
        flush_workqueue(commit_wq);
 
        if (!reiserfs_mounted_fs_count) {
@@ -3314,7 +3316,7 @@ int journal_mark_dirty(struct reiserfs_transaction_handle *th,
                journal->j_first = cn;
                journal->j_last = cn;
        }
-       sb->s_dirt = 1;
+       reiserfs_schedule_old_flush(sb);
        return 0;
 }
 
@@ -3952,7 +3954,7 @@ static int do_journal_end(struct reiserfs_transaction_handle *th,
         ** it tells us if we should continue with the journal_end, or just return
         */
        if (!check_journal_end(th, sb, nblocks, flags)) {
-               sb->s_dirt = 1;
+               reiserfs_schedule_old_flush(sb);
                wake_queued_writers(sb);
                reiserfs_async_progress_wait(sb);
                goto out;

diff --git a/fs/reiserfs/reiserfs.h b/fs/reiserfs/reiserfs.h
index 5c700550bb076b30334ce791a41d4c5d5078f8b2..33215f57ea06ce3026ef2d488832a337a361bd71 100644 (file)
--- a/fs/reiserfs/reiserfs.h
+++ b/fs/reiserfs/reiserfs.h
@@ -480,6 +480,11 @@ struct reiserfs_sb_info {
        struct dentry *priv_root;       /* root of /.reiserfs_priv */
        struct dentry *xattr_root;      /* root of /.reiserfs_priv/xattrs */
        int j_errno;
+
+       int work_queued;              /* non-zero delayed work is queued */
+       struct delayed_work old_work; /* old transactions flush delayed work */
+       spinlock_t old_work_lock;     /* protects old_work and work_queued */
+
 #ifdef CONFIG_QUOTA
        char *s_qf_names[MAXQUOTAS];
        int s_jquota_fmt;
@@ -2487,6 +2492,7 @@ void reiserfs_abort(struct super_block *sb, int errno, const char *fmt, ...);
 int reiserfs_allocate_list_bitmaps(struct super_block *s,
                                   struct reiserfs_list_bitmap *, unsigned int);
 
+void reiserfs_schedule_old_flush(struct super_block *s);
 void add_save_link(struct reiserfs_transaction_handle *th,
                   struct inode *inode, int truncate);
 int remove_save_link(struct inode *inode, int truncate);

diff --git a/fs/reiserfs/super.c b/fs/reiserfs/super.c
index 60cddb7e6389fe1c2c1e78aa060ae73bb826eba7..651ce767b55d8241e283b3001d7fc9e6d803b317 100644 (file)
--- a/fs/reiserfs/super.c
+++ b/fs/reiserfs/super.c
@@ -72,20 +72,58 @@ static int reiserfs_sync_fs(struct super_block *s, int wait)
        if (!journal_begin(&th, s, 1))
                if (!journal_end_sync(&th, s, 1))
                        reiserfs_flush_old_commits(s);
-       s->s_dirt = 0;  /* Even if it's not true.
-                        * We'll loop forever in sync_supers otherwise */
        reiserfs_write_unlock(s);
        return 0;
 }
 
-static void reiserfs_write_super(struct super_block *s)
+static void flush_old_commits(struct work_struct *work)
 {
+       struct reiserfs_sb_info *sbi;
+       struct super_block *s;
+
+       sbi = container_of(work, struct reiserfs_sb_info, old_work.work);
+       s = sbi->s_journal->j_work_sb;
+
+       spin_lock(&sbi->old_work_lock);
+       sbi->work_queued = 0;
+       spin_unlock(&sbi->old_work_lock);
+
        reiserfs_sync_fs(s, 1);
 }
 
+void reiserfs_schedule_old_flush(struct super_block *s)
+{
+       struct reiserfs_sb_info *sbi = REISERFS_SB(s);
+       unsigned long delay;
+
+       if (s->s_flags & MS_RDONLY)
+               return;
+
+       spin_lock(&sbi->old_work_lock);
+       if (!sbi->work_queued) {
+               delay = msecs_to_jiffies(dirty_writeback_interval * 10);
+               queue_delayed_work(system_long_wq, &sbi->old_work, delay);
+               sbi->work_queued = 1;
+       }
+       spin_unlock(&sbi->old_work_lock);
+}
+
+static void cancel_old_flush(struct super_block *s)
+{
+       struct reiserfs_sb_info *sbi = REISERFS_SB(s);
+
+       cancel_delayed_work_sync(&REISERFS_SB(s)->old_work);
+       spin_lock(&sbi->old_work_lock);
+       sbi->work_queued = 0;
+       spin_unlock(&sbi->old_work_lock);
+}
+
 static int reiserfs_freeze(struct super_block *s)
 {
        struct reiserfs_transaction_handle th;
+
+       cancel_old_flush(s);
+
        reiserfs_write_lock(s);
        if (!(s->s_flags & MS_RDONLY)) {
                int err = journal_begin(&th, s, 1);
@@ -99,7 +137,6 @@ static int reiserfs_freeze(struct super_block *s)
                        journal_end_sync(&th, s, 1);
                }
        }
-       s->s_dirt = 0;
        reiserfs_write_unlock(s);
        return 0;
 }
@@ -483,9 +520,6 @@ static void reiserfs_put_super(struct super_block *s)
 
        reiserfs_write_lock(s);
 
-       if (s->s_dirt)
-               reiserfs_write_super(s);
-
        /* change file system state to current state if it was mounted with read-write permissions */
        if (!(s->s_flags & MS_RDONLY)) {
                if (!journal_begin(&th, s, 10)) {
@@ -692,7 +726,6 @@ static const struct super_operations reiserfs_sops = {
        .dirty_inode = reiserfs_dirty_inode,
        .evict_inode = reiserfs_evict_inode,
        .put_super = reiserfs_put_super,
-       .write_super = reiserfs_write_super,
        .sync_fs = reiserfs_sync_fs,
        .freeze_fs = reiserfs_freeze,
        .unfreeze_fs = reiserfs_unfreeze,
@@ -1400,7 +1433,6 @@ static int reiserfs_remount(struct super_block *s, int *mount_flags, char *arg)
        err = journal_end(&th, s, 10);
        if (err)
                goto out_err;
-       s->s_dirt = 0;
 
        if (!(*mount_flags & MS_RDONLY)) {
                dquot_resume(s, -1);
@@ -1741,6 +1773,8 @@ static int reiserfs_fill_super(struct super_block *s, void *data, int silent)
        /* setup default block allocator options */
        reiserfs_init_alloc_options(s);
 
+       spin_lock_init(&sbi->old_work_lock);
+       INIT_DELAYED_WORK(&sbi->old_work, flush_old_commits);
        mutex_init(&sbi->lock);
        sbi->lock_depth = -1;
 
@@ -2003,6 +2037,8 @@ error_unlocked:
                reiserfs_write_unlock(s);
        }
 
+       cancel_delayed_work_sync(&REISERFS_SB(s)->old_work);
+
        reiserfs_free_bitmap_cache(s);
        if (SB_BUFFER_WITH_SB(s))
                brelse(SB_BUFFER_WITH_SB(s));