[PATCH] lockfs - xfs bits

From: Christoph Hellwig <hch@lst.de>

Remove all the code now in the VFS, make XFS's freeze ioctls use the new
infastructure and reorganize some code.

This code needs some work so the source files shared with 2.4 aren't
exposed to the new VFS interfaces directly.  You'll get an update once this
has been discussed with the other XFS developers and is implemented.  Note
that the current patch works fine and I wouldn't complain if it gets into
Linus' tree as-is.

fs/xfs/linux/xfs_ioctl.c

@@ -825,13 +825,14 @@ xfs_ioctl(
 	case XFS_IOC_FREEZE:
 		if (!capable(CAP_SYS_ADMIN))
 			return -EPERM;
-		xfs_fs_freeze(mp);
+
+		freeze_bdev(inode->i_sb->s_bdev);
 		return 0;
 
 	case XFS_IOC_THAW:
 		if (!capable(CAP_SYS_ADMIN))
 			return -EPERM;
-		xfs_fs_thaw(mp);
+		thaw_bdev(inode->i_sb->s_bdev, inode->i_sb);
 		return 0;
 
 	case XFS_IOC_GOINGDOWN: {

fs/xfs/linux/xfs_lrw.c

@@ -682,8 +682,6 @@ xfs_write(
 	io = &xip->i_iocore;
 	mp = io->io_mount;
 
-	xfs_check_frozen(mp, bdp, XFS_FREEZE_WRITE);
-
 	if (XFS_FORCED_SHUTDOWN(mp)) {
 		return -EIO;
 	}

fs/xfs/linux/xfs_super.c

@@ -589,28 +589,7 @@ STATIC void
 linvfs_freeze_fs(
 	struct super_block	*sb)
 {
-	vfs_t			*vfsp = LINVFS_GET_VFS(sb);
-	vnode_t			*vp;
-	int			error;
-
-	if (sb->s_flags & MS_RDONLY)
-		return;
-	VFS_ROOT(vfsp, &vp, error);
-	VOP_IOCTL(vp, LINVFS_GET_IP(vp), NULL, 0, XFS_IOC_FREEZE, 0, error);
-	VN_RELE(vp);
-}
-
-STATIC void
-linvfs_unfreeze_fs(
-	struct super_block	*sb)
-{
-	vfs_t			*vfsp = LINVFS_GET_VFS(sb);
-	vnode_t			*vp;
-	int			error;
-
-	VFS_ROOT(vfsp, &vp, error);
-	VOP_IOCTL(vp, LINVFS_GET_IP(vp), NULL, 0, XFS_IOC_THAW, 0, error);
-	VN_RELE(vp);
+	VFS_FREEZE(LINVFS_GET_VFS(sb));
 }
 
 STATIC struct dentry *
@@ -850,7 +829,6 @@ STATIC struct super_operations linvfs_sops = {
 	.write_super		= linvfs_write_super,
 	.sync_fs		= linvfs_sync_super,
 	.write_super_lockfs	= linvfs_freeze_fs,
-	.unlockfs		= linvfs_unfreeze_fs,
 	.statfs			= linvfs_statfs,
 	.remount_fs		= linvfs_remount,
 	.show_options		= linvfs_show_options,

fs/xfs/linux/xfs_vfs.c

@@ -230,6 +230,18 @@ vfs_force_shutdown(
 	((*bhvtovfsops(next)->vfs_force_shutdown)(next, fl, file, line));
 }
 
+void
+vfs_freeze(
+	struct bhv_desc		*bdp)
+{
+	struct bhv_desc		*next = bdp;
+
+	ASSERT(next);
+	while (! (bhvtovfsops(next))->vfs_freeze)
+		next = BHV_NEXT(next);
+	((*bhvtovfsops(next)->vfs_freeze)(next));
+}
+
 vfs_t *
 vfs_allocate( void )
 {

fs/xfs/linux/xfs_vfs.h

@@ -112,6 +112,7 @@ typedef int	(*vfs_quotactl_t)(bhv_desc_t *, int, int, caddr_t);
 typedef void	(*vfs_init_vnode_t)(bhv_desc_t *,
 				struct vnode *, bhv_desc_t *, int);
 typedef void	(*vfs_force_shutdown_t)(bhv_desc_t *, int, char *, int);
+typedef void	(*vfs_freeze_t)(bhv_desc_t *);
 
 typedef struct vfsops {
 	bhv_position_t		vf_position;	/* behavior chain position */
@@ -128,6 +129,7 @@ typedef struct vfsops {
 	vfs_quotactl_t		vfs_quotactl;	/* disk quota */
 	vfs_init_vnode_t	vfs_init_vnode;	/* initialize a new vnode */
 	vfs_force_shutdown_t	vfs_force_shutdown;	/* crash and burn */
+	vfs_freeze_t		vfs_freeze;	/* freeze fs for snapshot */
 } vfsops_t;
 
 /*
@@ -147,6 +149,7 @@ typedef struct vfsops {
 #define VFS_QUOTACTL(v, c,id,p, rv)	((rv) = vfs_quotactl(VHEAD(v), c,id,p))
 #define VFS_INIT_VNODE(v, vp,b,ul)	( vfs_init_vnode(VHEAD(v), vp,b,ul) )
 #define VFS_FORCE_SHUTDOWN(v, fl,f,l)	( vfs_force_shutdown(VHEAD(v), fl,f,l) )
+#define VFS_FREEZE(v)			( vfs_freeze(VHEAD(v)) )
 
 /*
  * PVFS's.  Operates on behavior descriptor pointers.
@@ -164,6 +167,7 @@ typedef struct vfsops {
 #define PVFS_QUOTACTL(b, c,id,p, rv)	((rv) = vfs_quotactl(b, c,id,p))
 #define PVFS_INIT_VNODE(b, vp,b2,ul)	( vfs_init_vnode(b, vp,b2,ul) )
 #define PVFS_FORCE_SHUTDOWN(b, fl,f,l)	( vfs_force_shutdown(b, fl,f,l) )
+#define PVFS_FREEZE(b)			( vfs_freeze(b) )
 
 extern int vfs_mount(bhv_desc_t *, struct xfs_mount_args *, struct cred *);
 extern int vfs_parseargs(bhv_desc_t *, char *, struct xfs_mount_args *, int);
@@ -178,6 +182,7 @@ extern int vfs_dmapiops(bhv_desc_t *, caddr_t);
 extern int vfs_quotactl(bhv_desc_t *, int, int, caddr_t);
 extern void vfs_init_vnode(bhv_desc_t *, struct vnode *, bhv_desc_t *, int);
 extern void vfs_force_shutdown(bhv_desc_t *, int, char *, int);
+extern void vfs_freeze(bhv_desc_t *);
 
 typedef struct bhv_vfsops {
 	struct vfsops		bhv_common;

fs/xfs/xfs_fsops.c

@@ -581,64 +581,26 @@ xfs_fs_log_dummy(xfs_mount_t *mp)
 	xfs_iunlock(ip, XFS_ILOCK_EXCL);
 }
 
-int
-xfs_fs_freeze(
-	xfs_mount_t	*mp)
-{
-	vfs_t		*vfsp;
-	/*REFERENCED*/
-	int		error;
-
-	vfsp = XFS_MTOVFS(mp);
-
-	/* Stop new writers */
-	xfs_start_freeze(mp, XFS_FREEZE_WRITE);
-
-	/* Flush the refcache */
-	xfs_refcache_purge_mp(mp);
-
-	/* Flush delalloc and delwri data */
-	VFS_SYNC(vfsp, SYNC_DELWRI|SYNC_WAIT, NULL, error);
-
-	/* Pause transaction subsystem */
-	xfs_start_freeze(mp, XFS_FREEZE_TRANS);
-
-	/* Flush any remaining inodes into buffers */
-	VFS_SYNC(vfsp, SYNC_ATTR|SYNC_WAIT, NULL, error);
-
-	/* Push all buffers out to disk */
-	xfs_binval(mp->m_ddev_targp);
-	if (mp->m_rtdev_targp) {
-		xfs_binval(mp->m_rtdev_targp);
-	}
-
-	/* Push the superblock and write an unmount record */
-	xfs_log_unmount_write(mp);
-	xfs_unmountfs_writesb(mp);
-
-	return 0;
-}
-
-int
-xfs_fs_thaw(
-	xfs_mount_t	*mp)
-{
-	xfs_finish_freeze(mp);
-	return 0;
-}
-
 int
 xfs_fs_goingdown(
 	xfs_mount_t	*mp,
 	__uint32_t	inflags)
 {
-	switch (inflags)
-	{
-	case XFS_FSOP_GOING_FLAGS_DEFAULT:
-		xfs_fs_freeze(mp);
-		xfs_force_shutdown(mp, XFS_FORCE_UMOUNT);
-		xfs_fs_thaw(mp);
+	if (!capable(CAP_SYS_ADMIN))
+		return -EPERM;
+
+	switch (inflags) {
+	case XFS_FSOP_GOING_FLAGS_DEFAULT: {
+		struct vfs *vfsp = XFS_MTOVFS(mp);
+		struct super_block *sb = freeze_bdev(vfsp->vfs_super->s_bdev);
+
+		if (sb) {
+			xfs_force_shutdown(mp, XFS_FORCE_UMOUNT);
+			thaw_bdev(sb->s_bdev, sb);
+		}
+
 		break;
+	}
 	case XFS_FSOP_GOING_FLAGS_LOGFLUSH:
 		xfs_force_shutdown(mp, XFS_FORCE_UMOUNT);
 		break;

fs/xfs/xfs_fsops.h

@@ -59,14 +59,6 @@ xfs_reserve_blocks(
 	__uint64_t		*inval,
 	xfs_fsop_resblks_t	*outval);
 
-int
-xfs_fs_freeze(
-	xfs_mount_t		*mp);
-
-int
-xfs_fs_thaw(
-	xfs_mount_t		*mp);
-
 int
 xfs_fs_goingdown(
 	xfs_mount_t		*mp,

fs/xfs/xfs_log.c

@@ -820,7 +820,7 @@ xfs_log_need_covered(xfs_mount_t *mp)
 	xlog_t		*log = mp->m_log;
 	vfs_t		*vfsp = XFS_MTOVFS(mp);
 
-	if (mp->m_frozen || XFS_FORCED_SHUTDOWN(mp) ||
+	if (vfsp->vfs_super->s_frozen || XFS_FORCED_SHUTDOWN(mp) ||
 	    (vfsp->vfs_flag & VFS_RDONLY))
 		return 0;
 

fs/xfs/xfs_mount.c

@@ -140,9 +140,6 @@ xfs_mount_init(void)
 	 */
 	xfs_trans_ail_init(mp);
 
-	/* Init freeze sync structures */
-	spinlock_init(&mp->m_freeze_lock, "xfs_freeze");
-	init_sv(&mp->m_wait_unfreeze, SV_DEFAULT, "xfs_freeze", 0);
 	atomic_set(&mp->m_active_trans, 0);
 
 	return mp;
@@ -192,8 +189,6 @@ xfs_mount_free(
 		VFS_REMOVEBHV(vfsp, &mp->m_bhv);
 	}
 
-	spinlock_destroy(&mp->m_freeze_lock);
-	sv_destroy(&mp->m_wait_unfreeze);
 	kmem_free(mp, sizeof(xfs_mount_t));
 }
 
@@ -1586,59 +1581,3 @@ xfs_mount_log_sbunit(
 	xfs_mod_sb(tp, fields);
 	xfs_trans_commit(tp, 0, NULL);
 }
-
-/* Functions to lock access out of the filesystem for forced
- * shutdown or snapshot.
- */
-
-void
-xfs_start_freeze(
-	xfs_mount_t	*mp,
-	int		level)
-{
-	unsigned long	s = mutex_spinlock(&mp->m_freeze_lock);
-
-	mp->m_frozen = level;
-	mutex_spinunlock(&mp->m_freeze_lock, s);
-
-	if (level == XFS_FREEZE_TRANS) {
-		while (atomic_read(&mp->m_active_trans) > 0)
-			delay(100);
-	}
-}
-
-void
-xfs_finish_freeze(
-	xfs_mount_t	*mp)
-{
-	unsigned long	s = mutex_spinlock(&mp->m_freeze_lock);
-
-	if (mp->m_frozen) {
-		mp->m_frozen = 0;
-		sv_broadcast(&mp->m_wait_unfreeze);
-	}
-
-	mutex_spinunlock(&mp->m_freeze_lock, s);
-}
-
-void
-xfs_check_frozen(
-	xfs_mount_t	*mp,
-	bhv_desc_t	*bdp,
-	int		level)
-{
-	unsigned long	s;
-
-	if (mp->m_frozen) {
-		s = mutex_spinlock(&mp->m_freeze_lock);
-
-		if (mp->m_frozen < level) {
-			mutex_spinunlock(&mp->m_freeze_lock, s);
-		} else {
-			sv_wait(&mp->m_wait_unfreeze, 0, &mp->m_freeze_lock, s);
-		}
-	}
-
-	if (level == XFS_FREEZE_TRANS)
-		atomic_inc(&mp->m_active_trans);
-}

fs/xfs/xfs_mount.h

@@ -379,10 +379,6 @@ typedef struct xfs_mount {
 	struct xfs_dmops	m_dm_ops;	/* vector of DMI ops */
 	struct xfs_qmops	m_qm_ops;	/* vector of XQM ops */
 	struct xfs_ioops	m_io_ops;	/* vector of I/O ops */
-	lock_t			m_freeze_lock;	/* Lock for m_frozen */
-	uint			m_frozen;	/* FS frozen for shutdown or
-						 * snapshot */
-	sv_t			m_wait_unfreeze;/* waiting to unfreeze */
 	atomic_t		m_active_trans;	/* number trans frozen */
 } xfs_mount_t;
 
@@ -558,16 +554,6 @@ extern void	xfs_initialize_perag(xfs_mount_t *, int);
 extern void	xfs_xlatesb(void *, struct xfs_sb *, int, xfs_arch_t,
 			__int64_t);
 
-/*
- * Flags for freeze operations.
- */
-#define XFS_FREEZE_WRITE	1
-#define XFS_FREEZE_TRANS	2
-
-extern void	xfs_start_freeze(xfs_mount_t *, int);
-extern void	xfs_finish_freeze(xfs_mount_t *);
-extern void	xfs_check_frozen(xfs_mount_t *, bhv_desc_t *, int);
-
 extern struct vfsops xfs_vfsops;
 extern struct vnodeops xfs_vnodeops;
 

fs/xfs/xfs_trans.c

@@ -131,7 +131,9 @@ xfs_trans_alloc(
 	xfs_mount_t	*mp,
 	uint		type)
 {
-	xfs_check_frozen(mp, NULL, XFS_FREEZE_TRANS);
+	vfs_check_frozen(XFS_MTOVFS(mp)->vfs_super, SB_FREEZE_TRANS);
+	atomic_inc(&mp->m_active_trans);
+
 	return (_xfs_trans_alloc(mp, type));
 
 }

fs/xfs/xfs_vfsops.c

@@ -1858,6 +1858,20 @@ xfs_showargs(
 	return 0;
 }
 
+STATIC void
+xfs_freeze(
+	bhv_desc_t	*bdp)
+{
+	xfs_mount_t	*mp = XFS_BHVTOM(bdp);
+
+	while (atomic_read(&mp->m_active_trans) > 0)
+		delay(100);
+
+	/* Push the superblock and write an unmount record */
+	xfs_log_unmount_write(mp);
+	xfs_unmountfs_writesb(mp);
+}
+
 
 vfsops_t xfs_vfsops = {
 	BHV_IDENTITY_INIT(VFS_BHV_XFS,VFS_POSITION_XFS),
@@ -1874,4 +1888,5 @@ vfsops_t xfs_vfsops = {
 	.vfs_quotactl		= (vfs_quotactl_t)fs_nosys,
 	.vfs_init_vnode		= xfs_initialize_vnode,
 	.vfs_force_shutdown	= xfs_do_force_shutdown,
+	.vfs_freeze		= xfs_freeze,
 };