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
--- a/fs/super.c
+++ b/fs/super.c
@@ -283,42 +283,6 @@
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 @@
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..d5fa7b799 100644
--- 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
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1942,7 +1942,6 @@
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 @@
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 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,