Get userland visible flags added for snapshots to give a few days

advance preparation for them to get migrated into place so that
subsequent changes in utilities will not fail to compile for lack
of up-to-date header files in /usr/include.

3 files changed, 40 insertions, 5 deletions

diff --git a/sys/sys/mount.h b/sys/sys/mount.h
index 5e3484e..5f963c2 100644
--- a/sys/sys/mount.h
+++ b/sys/sys/mount.h
@@ -114,6 +114,7 @@ struct mount {
 	struct vnode	*mnt_syncer;		/* syncer vnode */
 	struct vnodelst	mnt_vnodelist;		/* list of vnodes this mount */
 	struct lock	mnt_lock;		/* mount structure lock */
+	int		mnt_writeopcount;	/* write syscalls in progress */
 	int		mnt_flag;		/* flags shared with user */
 	int		mnt_kern_flag;		/* kernel only flags */
 	int		mnt_maxsymlinklen;	/* max size of short symlink */
@@ -165,7 +166,6 @@ struct mount {
  * Mask of flags that are visible to statfs()
  * XXX I think that this could now become (~(MNT_CMDFLAGS))
  * but the 'mount' program may need changing to handle this.
- * XXX MNT_EXPUBLIC is presently left out. I don't know why.
  */
 #define	MNT_VISFLAGMASK	(MNT_RDONLY	| MNT_SYNCHRONOUS | MNT_NOEXEC	| \
 			MNT_NOSUID	| MNT_NODEV	| MNT_UNION	| \
@@ -174,8 +174,7 @@ struct mount {
 			MNT_LOCAL	| MNT_USER	| MNT_QUOTA	| \
 			MNT_ROOTFS	| MNT_NOATIME	| MNT_NOCLUSTERR| \
 			MNT_NOCLUSTERW	| MNT_SUIDDIR	| MNT_SOFTDEP	| \
-			MNT_IGNORE \
-			/*	| MNT_EXPUBLIC */)
+			MNT_IGNORE	| MNT_EXPUBLIC	| MNT_NOSYMFOLLOW)
 /*
  * External filesystem command modifier flags.
  * Unmount can use the MNT_FORCE flag.
@@ -185,7 +184,15 @@ struct mount {
 #define	MNT_DELEXPORT	0x00020000	/* delete export host lists */
 #define	MNT_RELOAD	0x00040000	/* reload filesystem data */
 #define	MNT_FORCE	0x00080000	/* force unmount or readonly change */
-#define MNT_CMDFLAGS	(MNT_UPDATE|MNT_DELEXPORT|MNT_RELOAD|MNT_FORCE)
+#define	MNT_SNAPSHOT	0x01000000	/* snapshot the filesystem */
+#define MNT_CMDFLAGS   (MNT_UPDATE	| MNT_DELEXPORT	| MNT_RELOAD	| \
+			MNT_FORCE	| MNT_SNAPSHOT)
+/*
+ * Still available
+ */
+#define	MNT_SPARE1	0x02000000
+#define	MNT_SPARE2	0x04000000
+#define	MNT_SPARE3	0x08000000
 /*
  * Internal filesystem control flags stored in mnt_kern_flag.
  *
@@ -196,6 +203,8 @@ struct mount {
 #define MNTK_UNMOUNT	0x01000000	/* unmount in progress */
 #define	MNTK_MWAIT	0x02000000	/* waiting for unmount to finish */
 #define MNTK_WANTRDWR	0x04000000	/* upgrade to read/write requested */
+#define	MNTK_SUSPEND	0x08000000	/* request write suspension */
+#define	MNTK_SUSPENDED	0x10000000	/* write operations are suspended */
 
 /*
  * Sysctl CTL_VFS definitions.
diff --git a/sys/sys/stat.h b/sys/sys/stat.h
index 21cfbc4..15367b3 100644
--- a/sys/sys/stat.h
+++ b/sys/sys/stat.h
@@ -222,6 +222,7 @@ struct nstat {
 #define	SF_IMMUTABLE	0x00020000	/* file may not be changed */
 #define	SF_APPEND	0x00040000	/* writes to file may only append */
 #define	SF_NOUNLINK	0x00100000	/* file may not be removed or renamed */
+#define	SF_SNAPSHOT	0x00200000	/* snapshot inode */
 
 #ifdef _KERNEL
 /*
diff --git a/sys/ufs/ffs/fs.h b/sys/ufs/ffs/fs.h
index d93f2a7..5d76aee 100644
--- a/sys/ufs/ffs/fs.h
+++ b/sys/ufs/ffs/fs.h
@@ -139,6 +139,30 @@
 #define DEFAULTOPT	FS_OPTTIME
 
 /*
+ * The maximum number of snapshot nodes that can be associated
+ * with each filesystem. This limit affects only the number of
+ * snapshot files that can be recorded within the superblock so
+ * that they can be found when the filesystem is mounted. However,
+ * maintaining too many will slow the filesystem performance, so
+ * having this limit is a good idea.
+ */
+#define FSMAXSNAP 20
+
+/*
+ * Used to identify special blocks in snapshots:
+ *
+ * BLK_NOCOPY - A block that was unallocated at the time the snapshot
+ *	was taken, hence does not need to be copied when written.
+ * BLK_SNAP - A block held by another snapshot that is not needed by this
+ *	snapshot. When the other snapshot is freed, the BLK_SNAP entries
+ *	are converted to BLK_NOCOPY. These are needed to allow fsck to
+ *	identify blocks that are in use by other snapshots (which are
+ *	expunged from this snapshot).
+ */
+#define BLK_NOCOPY ((ufs_daddr_t)(1))
+#define BLK_SNAP ((ufs_daddr_t)(2))
+
+/*
  * Per cylinder group information; summarized in blocks allocated
  * from first cylinder group data blocks.  These blocks have to be
  * read in from fs_csaddr (size fs_cssize) in addition to the
@@ -230,7 +254,8 @@ struct fs {
 	int32_t	 *fs_maxcluster;	/* max cluster in each cyl group */
 	int32_t	 fs_cpc;		/* cyl per cycle in postbl */
 	int16_t	 fs_opostbl[16][8];	/* old rotation block list head */
-	int32_t	 fs_sparecon[50];	/* reserved for future constants */
+	int32_t	 fs_snapinum[FSMAXSNAP];/* list of snapshot inode numbers */
+	int32_t	 fs_sparecon[30];	/* reserved for future constants */
 	int32_t	 fs_contigsumsize;	/* size of cluster summary array */ 
 	int32_t	 fs_maxsymlinklen;	/* max length of an internal symlink */
 	int32_t	 fs_inodefmt;		/* format of on-disk inodes */