2.4.25--pre4 VFS lvm_snapshots

diff -Nuar a/drivers/md/lvm.c b/drivers/md/lvm.c
@@ -236,9 +236,6 @@
 #define DEVICE_OFF(device)
 #define LOCAL_END_REQUEST
 
-/* lvm_do_lv_create calls fsync_dev_lockfs()/unlockfs() */
-/* #define	LVM_VFS_ENHANCEMENT */
-
 #include <linux/config.h>
 #include <linux/module.h>
 #include <linux/kernel.h>

@@ -2250,12 +2247,8 @@
 	if (lv_ptr->lv_access & LV_SNAPSHOT) {
 		lv_t *org = lv_ptr->lv_snapshot_org, *last;
 
-		/* sync the original logical volume */
-		fsync_dev(org->lv_dev);
-#ifdef	LVM_VFS_ENHANCEMENT
 		/* VFS function call to sync and lock the filesystem */
 		fsync_dev_lockfs(org->lv_dev);
-#endif
 
 		down_write(&org->lv_lock);
 		org->lv_access |= LV_SNAPSHOT_ORG;

@@ -2281,11 +2274,9 @@
 	else
 		set_device_ro(lv_ptr->lv_dev, 1);
 
-#ifdef	LVM_VFS_ENHANCEMENT
 /* VFS function call to unlock the filesystem */
 	if (lv_ptr->lv_access & LV_SNAPSHOT)
 		unlockfs(lv_ptr->lv_snapshot_org->lv_dev);
-#endif
 
 	lvm_gendisk.part[MINOR(lv_ptr->lv_dev)].de =
 	    lvm_fs_create_lv(vg_ptr, lv_ptr);

diff -Nuar a/fs/buffer.c b/fs/buffer.c
@@ -419,6 +419,34 @@
 	fsync_dev(dev);
 }
 
+int fsync_dev_lockfs(kdev_t dev)
+{
+	/* you are not allowed to try locking all the filesystems
+	 * on the system, your chances of getting through without
+	 * total deadlock are slim to none.
+	 */
+	if (!dev)
+		return fsync_dev(dev);
+
+	sync_buffers(dev, 0);
+
+	lock_kernel();
+	/* note, the FS might need to start transactions to 
+	 * sync the inodes, or the quota, no locking until
+	 * after these are done
+	 */
+	sync_inodes(dev);
+	DQUOT_SYNC(dev);
+	/* if inodes or quotas could be dirtied during the
+	 * sync_supers_lockfs call, the FS is responsible for getting
+	 * them on disk, without deadlocking against the lock
+	 */
+	sync_supers_lockfs(dev);
+	unlock_kernel();
+
+	return sync_buffers(dev, 1);
+}
+
 asmlinkage long sys_sync(void)
 {
 	fsync_dev(0);

diff -Nuar a/fs/reiserfs/super.c b/fs/reiserfs/super.c
@@ -73,7 +73,7 @@
     reiserfs_prepare_for_journal(s, SB_BUFFER_WITH_SB(s), 1);
     journal_mark_dirty(&th, s, SB_BUFFER_WITH_SB (s));
     reiserfs_block_writes(&th) ;
-    journal_end(&th, s, 1) ;
+    journal_end_sync(&th, s, 1) ;
   }
   s->s_dirt = dirty;
   unlock_kernel() ;

108 lines not on this page · raw message

diff -Nuar a/include/linux/fs.h b/include/linux/fs.h
@@ -1277,6 +1277,7 @@
 extern int sync_buffers(kdev_t, int);
 extern void sync_dev(kdev_t);
 extern int fsync_dev(kdev_t);
+extern int fsync_dev_lockfs(kdev_t);
 extern int fsync_super(struct super_block *);
 extern int fsync_no_super(kdev_t);
 extern void sync_inodes_sb(struct super_block *);

@@ -1295,6 +1296,8 @@
 extern int filemap_fdatasync(struct address_space *);
 extern int filemap_fdatawait(struct address_space *);
 extern void sync_supers(kdev_t dev, int wait);
+extern void sync_supers_lockfs(kdev_t);
+extern void unlockfs(kdev_t);
 extern int bmap(struct inode *, int);
 extern int notify_change(struct dentry *, struct iattr *);
 extern int permission(struct inode *, int);

diff -Nuar a/kernel/ksyms.c b/kernel/ksyms.c
@@ -194,6 +194,8 @@
 EXPORT_SYMBOL(invalidate_inode_pages);
 EXPORT_SYMBOL(truncate_inode_pages);
 EXPORT_SYMBOL(fsync_dev);
+EXPORT_SYMBOL(fsync_dev_lockfs);
+EXPORT_SYMBOL(unlockfs);
 EXPORT_SYMBOL(fsync_no_super);
 EXPORT_SYMBOL(permission);
 EXPORT_SYMBOL(vfs_permission);