[PATCH] BLOCK: Move functions out of buffer code [try #6]

Move some functions out of the buffering code that aren't strictly buffering
specific.  This is a precursor to being able to disable the block layer.

 (*) Moved some stuff out of fs/buffer.c:

     (*) The file sync and general sync stuff moved to fs/sync.c.

     (*) The superblock sync stuff moved to fs/super.c.

     (*) do_invalidatepage() moved to mm/truncate.c.

     (*) try_to_release_page() moved to mm/filemap.c.

 (*) Moved some related declarations between header files:

     (*) declarations for do_invalidatepage() and try_to_release_page() moved
     	 to linux/mm.h.

     (*) __set_page_dirty_buffers() moved to linux/buffer_head.h.

Signed-Off-By: David Howells <dhowells@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

1 files changed, 113 insertions, 0 deletions

diff --git a/fs/sync.c b/fs/sync.c
index 955aef04da28..1de747b5ddb9 100644
--- a/fs/sync.c
+++ b/fs/sync.c
@@ -10,11 +10,124 @@
 #include <linux/syscalls.h>
 #include <linux/linkage.h>
 #include <linux/pagemap.h>
+#include <linux/quotaops.h>
+#include <linux/buffer_head.h>
 
 #define VALID_FLAGS (SYNC_FILE_RANGE_WAIT_BEFORE|SYNC_FILE_RANGE_WRITE| \
                         SYNC_FILE_RANGE_WAIT_AFTER)
 
 /*
+ * sync everything.  Start out by waking pdflush, because that writes back
+ * all queues in parallel.
+ */
+static void do_sync(unsigned long wait)
+{
+        wakeup_pdflush(0);
+        sync_inodes(0);         /* All mappings, inodes and their blockdevs */
+        DQUOT_SYNC(NULL);
+        sync_supers();          /* Write the superblocks */
+        sync_filesystems(0);    /* Start syncing the filesystems */
+        sync_filesystems(wait); /* Waitingly sync the filesystems */
+        sync_inodes(wait);      /* Mappings, inodes and blockdevs, again. */
+        if (!wait)
+                printk("Emergency Sync complete\n");
+        if (unlikely(laptop_mode))
+                laptop_sync_completion();
+}
+
+asmlinkage long sys_sync(void)
+{
+        do_sync(1);
+        return 0;
+}
+
+void emergency_sync(void)
+{
+        pdflush_operation(do_sync, 0);
+}
+
+/*
+ * Generic function to fsync a file.
+ *
+ * filp may be NULL if called via the msync of a vma.
+ */
+int file_fsync(struct file *filp, struct dentry *dentry, int datasync)
+{
+        struct inode * inode = dentry->d_inode;
+        struct super_block * sb;
+        int ret, err;
+
+        /* sync the inode to buffers */
+        ret = write_inode_now(inode, 0);
+
+        /* sync the superblock to buffers */
+        sb = inode->i_sb;
+        lock_super(sb);
+        if (sb->s_op->write_super)
+                sb->s_op->write_super(sb);
+        unlock_super(sb);
+
+        /* .. finally sync the buffers to disk */
+        err = sync_blockdev(sb->s_bdev);
+        if (!ret)
+                ret = err;
+        return ret;
+}
+
+long do_fsync(struct file *file, int datasync)
+{
+        int ret;
+        int err;
+        struct address_space *mapping = file->f_mapping;
+
+        if (!file->f_op || !file->f_op->fsync) {
+                /* Why?  We can still call filemap_fdatawrite */
+                ret = -EINVAL;
+                goto out;
+        }
+
+        ret = filemap_fdatawrite(mapping);
+
+        /*
+         * We need to protect against concurrent writers, which could cause
+         * livelocks in fsync_buffers_list().
+         */
+        mutex_lock(&mapping->host->i_mutex);
+        err = file->f_op->fsync(file, file->f_dentry, datasync);
+        if (!ret)
+                ret = err;
+        mutex_unlock(&mapping->host->i_mutex);
+        err = filemap_fdatawait(mapping);
+        if (!ret)
+                ret = err;
+out:
+        return ret;
+}
+
+static long __do_fsync(unsigned int fd, int datasync)
+{
+        struct file *file;
+        int ret = -EBADF;
+
+        file = fget(fd);
+        if (file) {
+                ret = do_fsync(file, datasync);
+                fput(file);
+        }
+        return ret;
+}
+
+asmlinkage long sys_fsync(unsigned int fd)
+{
+        return __do_fsync(fd, 0);
+}
+
+asmlinkage long sys_fdatasync(unsigned int fd)
+{
+        return __do_fsync(fd, 1);
+}
+
+/*
  * sys_sync_file_range() permits finely controlled syncing over a segment of
  * a file in the range offset .. (offset+nbytes-1) inclusive.  If nbytes is
  * zero then sys_sync_file_range() will operate from offset out to EOF.