[XFS] replace vn_get usage by ihold

SGI-PV: 938306
SGI-Modid: xfs-linux:xfs-kern:194627a

Signed-off-by: Christoph Hellwig <hch@sgi.com>
Signed-off-by: Nathan Scott <nathans@sgi.com>

fs/xfs/linux-2.6/xfs_vnode.c

@@ -162,30 +162,6 @@ vn_initialize(
 	return vp;
 }
 
-/*
- * Get a reference on a vnode.
- */
-vnode_t *
-vn_get(
-	struct vnode	*vp,
-	vmap_t		*vmap)
-{
-	struct inode	*inode;
-
-	XFS_STATS_INC(vn_get);
-	inode = LINVFS_GET_IP(vp);
-	if (inode->i_state & I_FREEING)
-		return NULL;
-
-	inode = ilookup(vmap->v_vfsp->vfs_super, vmap->v_ino);
-	if (!inode)	/* Inode not present */
-		return NULL;
-
-	vn_trace_exit(vp, "vn_get", (inst_t *)__return_address);
-
-	return vp;
-}
-
 /*
  * Revalidate the Linux inode from the vattr.
  * Note: i_size _not_ updated; we must hold the inode

fs/xfs/linux-2.6/xfs_vnode.h

@@ -504,20 +504,6 @@ extern void	vn_init(void);
 extern int	vn_wait(struct vnode *);
 extern vnode_t	*vn_initialize(struct inode *);
 
-/*
- * Acquiring and invalidating vnodes:
- *
- *	if (vn_get(vp, version, 0))
- *		...;
- *	vn_purge(vp, version);
- *
- * vn_get and vn_purge must be called with vmap_t arguments, sampled
- * while a lock that the vnode's VOP_RECLAIM function acquires is
- * held, to ensure that the vnode sampled with the lock held isn't
- * recycled (VOP_RECLAIMed) or deallocated between the release of the lock
- * and the subsequent vn_get or vn_purge.
- */
-
 /*
  * vnode_map structures _must_ match vn_epoch and vnode structure sizes.
  */
@@ -532,7 +518,6 @@ typedef struct vnode_map {
 			 (vmap).v_ino	 = (vp)->v_inode.i_ino; }
 
 extern void	vn_purge(struct vnode *, vmap_t *);
-extern vnode_t	*vn_get(struct vnode *, vmap_t *);
 extern int	vn_revalidate(struct vnode *);
 extern void	vn_revalidate_core(struct vnode *, vattr_t *);
 extern void	vn_remove(struct vnode *);
@@ -560,6 +545,12 @@ extern void	vn_rele(struct vnode *);
 #define VN_RELE(vp)		(iput(LINVFS_GET_IP(vp)))
 #endif
 
+static inline struct vnode *vn_grab(struct vnode *vp)
+{
+	struct inode *inode = igrab(LINVFS_GET_IP(vp));
+	return inode ? LINVFS_GET_VP(inode) : NULL;
+}
+
 /*
  * Vname handling macros.
  */

fs/xfs/quota/xfs_qm_syscalls.c

@@ -1053,16 +1053,15 @@ xfs_qm_dqrele_all_inodes(
 	struct xfs_mount *mp,
 	uint		 flags)
 {
-	vmap_t		vmap;
 	xfs_inode_t	*ip, *topino;
 	uint		ireclaims;
 	vnode_t		*vp;
 	boolean_t	vnode_refd;
 
 	ASSERT(mp->m_quotainfo);
 
-again:
 	XFS_MOUNT_ILOCK(mp);
+again:
 	ip = mp->m_inodes;
 	if (ip == NULL) {
 		XFS_MOUNT_IUNLOCK(mp);
@@ -1090,18 +1089,14 @@ xfs_qm_dqrele_all_inodes(
 		}
 		vnode_refd = B_FALSE;
 		if (xfs_ilock_nowait(ip, XFS_ILOCK_EXCL) == 0) {
-			/*
-			 * Sample vp mapping while holding the mplock, lest
-			 * we come across a non-existent vnode.
-			 */
-			VMAP(vp, vmap);
 			ireclaims = mp->m_ireclaims;
 			topino = mp->m_inodes;
-			XFS_MOUNT_IUNLOCK(mp);
+			vp = vn_grab(vp);
+			if (!vp)
+				goto again;
 
+			XFS_MOUNT_IUNLOCK(mp);
 			/* XXX restart limit ? */
-			if ( ! (vp = vn_get(vp, &vmap)))
-				goto again;
 			xfs_ilock(ip, XFS_ILOCK_EXCL);
 			vnode_refd = B_TRUE;
 		} else {
@@ -1137,7 +1132,6 @@ xfs_qm_dqrele_all_inodes(
 		 */
 		if (topino != mp->m_inodes || mp->m_ireclaims != ireclaims) {
 			/* XXX use a sentinel */
-			XFS_MOUNT_IUNLOCK(mp);
 			goto again;
 		}
 		ip = ip->i_mnext;

fs/xfs/xfs_vfsops.c

@@ -906,7 +906,6 @@ xfs_sync_inodes(
 	xfs_inode_t	*ip_next;
 	xfs_buf_t	*bp;
 	vnode_t		*vp = NULL;
-	vmap_t		vmap;
 	int		error;
 	int		last_error;
 	uint64_t	fflag;
@@ -1101,48 +1100,21 @@ xfs_sync_inodes(
 		 * lock in xfs_ireclaim() after the inode is pulled from
 		 * the mount list will sleep until we release it here.
 		 * This keeps the vnode from being freed while we reference
-		 * it.  It is also cheaper and simpler than actually doing
-		 * a vn_get() for every inode we touch here.
+		 * it.
 		 */
 		if (xfs_ilock_nowait(ip, lock_flags) == 0) {
-
 			if ((flags & SYNC_BDFLUSH) || (vp == NULL)) {
 				ip = ip->i_mnext;
 				continue;
 			}
 
-			/*
-			 * We need to unlock the inode list lock in order
-			 * to lock the inode. Insert a marker record into
-			 * the inode list to remember our position, dropping
-			 * the lock is now done inside the IPOINTER_INSERT
-			 * macro.
-			 *
-			 * We also use the inode list lock to protect us
-			 * in taking a snapshot of the vnode version number
-			 * for use in calling vn_get().
-			 */
-			VMAP(vp, vmap);
-			IPOINTER_INSERT(ip, mp);
-
-			vp = vn_get(vp, &vmap);
+			vp = vn_grab(vp);
 			if (vp == NULL) {
-				/*
-				 * The vnode was reclaimed once we let go
-				 * of the inode list lock.  Skip to the
-				 * next list entry. Remove the marker.
-				 */
-
-				XFS_MOUNT_ILOCK(mp);
-
-				mount_locked = B_TRUE;
-				vnode_refed  = B_FALSE;
-
-				IPOINTER_REMOVE(ip, mp);
-
+				ip = ip->i_mnext;
 				continue;
 			}
 
+			IPOINTER_INSERT(ip, mp);
 			xfs_ilock(ip, lock_flags);
 
 			ASSERT(vp == XFS_ITOV(ip));