vfs: Move syncing code from super.c to sync.c (version 4)

Move sync_filesystems(), __fsync_super(), fsync_super() from
super.c to sync.c where it fits better.

[build fixes folded]

Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

diff --git a/fs/super.c b/fs/super.c
index c8ce5ed..f822c74 100644 (file)
--- a/fs/super.c
+++ b/fs/super.c
@@ -283,42 +283,6 @@ void unlock_super(struct super_block * sb)
 EXPORT_SYMBOL(lock_super);
 EXPORT_SYMBOL(unlock_super);
 
-/*
- * Do the filesystem syncing work. For simple filesystems sync_inodes_sb(sb, 0)
- * just dirties buffers with inodes so we have to submit IO for these buffers
- * via __sync_blockdev(). This also speeds up the wait == 1 case since in that
- * case write_inode() functions do sync_dirty_buffer() and thus effectively
- * write one block at a time.
- */
-static int __fsync_super(struct super_block *sb, int wait)
-{
-       vfs_dq_sync(sb);
-       sync_inodes_sb(sb, wait);
-       lock_super(sb);
-       if (sb->s_dirt && sb->s_op->write_super)
-               sb->s_op->write_super(sb);
-       unlock_super(sb);
-       if (sb->s_op->sync_fs)
-               sb->s_op->sync_fs(sb, wait);
-       return __sync_blockdev(sb->s_bdev, wait);
-}
-
-/*
- * Write out and wait upon all dirty data associated with this
- * superblock.  Filesystem data as well as the underlying block
- * device.  Takes the superblock lock.
- */
-int fsync_super(struct super_block *sb)
-{
-       int ret;
-
-       ret = __fsync_super(sb, 0);
-       if (ret < 0)
-               return ret;
-       return __fsync_super(sb, 1);
-}
-EXPORT_SYMBOL_GPL(fsync_super);
-
 /**
  *     generic_shutdown_super  -       common helper for ->kill_sb()
  *     @sb: superblock to kill
@@ -473,55 +437,6 @@ restart:
        spin_unlock(&sb_lock);
 }
 
-/*
- * Sync all the data for all the filesystems (called by sys_sync() and
- * emergency sync)
- *
- * This operation is careful to avoid the livelock which could easily happen
- * if two or more filesystems are being continuously dirtied.  s_need_sync
- * is used only here.  We set it against all filesystems and then clear it as
- * we sync them.  So redirtied filesystems are skipped.
- *
- * But if process A is currently running sync_filesystems and then process B
- * calls sync_filesystems as well, process B will set all the s_need_sync
- * flags again, which will cause process A to resync everything.  Fix that with
- * a local mutex.
- */
-void sync_filesystems(int wait)
-{
-       struct super_block *sb;
-       static DEFINE_MUTEX(mutex);
-
-       mutex_lock(&mutex);             /* Could be down_interruptible */
-       spin_lock(&sb_lock);
-       list_for_each_entry(sb, &super_blocks, s_list) {
-               if (sb->s_flags & MS_RDONLY)
-                       continue;
-               sb->s_need_sync = 1;
-       }
-
-restart:
-       list_for_each_entry(sb, &super_blocks, s_list) {
-               if (!sb->s_need_sync)
-                       continue;
-               sb->s_need_sync = 0;
-               if (sb->s_flags & MS_RDONLY)
-                       continue;       /* hm.  Was remounted r/o meanwhile */
-               sb->s_count++;
-               spin_unlock(&sb_lock);
-               down_read(&sb->s_umount);
-               if (sb->s_root)
-                       __fsync_super(sb, wait);
-               up_read(&sb->s_umount);
-               /* restart only when sb is no longer on the list */
-               spin_lock(&sb_lock);
-               if (__put_super_and_need_restart(sb))
-                       goto restart;
-       }
-       spin_unlock(&sb_lock);
-       mutex_unlock(&mutex);
-}
-
 /**
  *     get_super - get the superblock of a device
  *     @bdev: device to get the superblock for

diff --git a/fs/sync.c b/fs/sync.c
index be0798c..d5fa7b7 100644 (file)
--- a/fs/sync.c
+++ b/fs/sync.c
@@ -18,6 +18,91 @@
 #define VALID_FLAGS (SYNC_FILE_RANGE_WAIT_BEFORE|SYNC_FILE_RANGE_WRITE| \
                        SYNC_FILE_RANGE_WAIT_AFTER)
 
+/*
+ * Do the filesystem syncing work. For simple filesystems sync_inodes_sb(sb, 0)
+ * just dirties buffers with inodes so we have to submit IO for these buffers
+ * via __sync_blockdev(). This also speeds up the wait == 1 case since in that
+ * case write_inode() functions do sync_dirty_buffer() and thus effectively
+ * write one block at a time.
+ */
+static int __fsync_super(struct super_block *sb, int wait)
+{
+       vfs_dq_sync(sb);
+       sync_inodes_sb(sb, wait);
+       lock_super(sb);
+       if (sb->s_dirt && sb->s_op->write_super)
+               sb->s_op->write_super(sb);
+       unlock_super(sb);
+       if (sb->s_op->sync_fs)
+               sb->s_op->sync_fs(sb, wait);
+       return __sync_blockdev(sb->s_bdev, wait);
+}
+
+/*
+ * Write out and wait upon all dirty data associated with this
+ * superblock.  Filesystem data as well as the underlying block
+ * device.  Takes the superblock lock.
+ */
+int fsync_super(struct super_block *sb)
+{
+       int ret;
+
+       ret = __fsync_super(sb, 0);
+       if (ret < 0)
+               return ret;
+       return __fsync_super(sb, 1);
+}
+EXPORT_SYMBOL_GPL(fsync_super);
+
+/*
+ * Sync all the data for all the filesystems (called by sys_sync() and
+ * emergency sync)
+ *
+ * This operation is careful to avoid the livelock which could easily happen
+ * if two or more filesystems are being continuously dirtied.  s_need_sync
+ * is used only here.  We set it against all filesystems and then clear it as
+ * we sync them.  So redirtied filesystems are skipped.
+ *
+ * But if process A is currently running sync_filesystems and then process B
+ * calls sync_filesystems as well, process B will set all the s_need_sync
+ * flags again, which will cause process A to resync everything.  Fix that with
+ * a local mutex.
+ */
+static void sync_filesystems(int wait)
+{
+       struct super_block *sb;
+       static DEFINE_MUTEX(mutex);
+
+       mutex_lock(&mutex);             /* Could be down_interruptible */
+       spin_lock(&sb_lock);
+       list_for_each_entry(sb, &super_blocks, s_list) {
+               if (sb->s_flags & MS_RDONLY)
+                       continue;
+               sb->s_need_sync = 1;
+       }
+
+restart:
+       list_for_each_entry(sb, &super_blocks, s_list) {
+               if (!sb->s_need_sync)
+                       continue;
+               sb->s_need_sync = 0;
+               if (sb->s_flags & MS_RDONLY)
+                       continue;       /* hm.  Was remounted r/o meanwhile */
+               sb->s_count++;
+               spin_unlock(&sb_lock);
+               down_read(&sb->s_umount);
+               if (sb->s_root)
+                       __fsync_super(sb, wait);
+               up_read(&sb->s_umount);
+               /* restart only when sb is no longer on the list */
+               spin_lock(&sb_lock);
+               if (__put_super_and_need_restart(sb))
+                       goto restart;
+       }
+       spin_unlock(&sb_lock);
+       mutex_unlock(&mutex);
+}
+
 SYSCALL_DEFINE0(sync)
 {
        sync_filesystems(0);

diff --git a/include/linux/fs.h b/include/linux/fs.h
index f00df65..d3f7159 100644 (file)
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1942,7 +1942,6 @@ extern struct super_block *freeze_bdev(struct block_device *);
 extern void emergency_thaw_all(void);
 extern int thaw_bdev(struct block_device *bdev, struct super_block *sb);
 extern int fsync_bdev(struct block_device *);
-extern int fsync_super(struct super_block *);
 extern int fsync_no_super(struct block_device *);
 #else
 static inline void bd_forget(struct inode *inode) {}
@@ -1959,6 +1958,7 @@ static inline int thaw_bdev(struct block_device *bdev, struct super_block *sb)
        return 0;
 }
 #endif
+extern int fsync_super(struct super_block *);
 extern const struct file_operations def_blk_fops;
 extern const struct file_operations def_chr_fops;
 extern const struct file_operations bad_sock_fops;
@@ -2077,7 +2077,6 @@ extern int filemap_fdatawrite_range(struct address_space *mapping,
 
 extern int vfs_fsync(struct file *file, struct dentry *dentry, int datasync);
 extern void sync_supers(void);
-extern void sync_filesystems(int wait);
 extern void emergency_sync(void);
 extern void emergency_remount(void);
 extern int do_remount_sb(struct super_block *sb, int flags,