xfs: split out inode walk inode grabbing

When doing read side inode cache walks, the code to validate and
grab an inode is common to all callers. Split it out of the execute
callbacks in preparation for batching lookups. Similarly, split out
the inode reference dropping from the execute callbacks into the
main lookup look to be symmetric with the grab.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Alex Elder <aelder@sgi.com>

fs/xfs/linux-2.6/xfs_sync.c

@@ -39,6 +39,33 @@
 #include <linux/kthread.h>
 #include <linux/freezer.h>
 
+STATIC int
+xfs_inode_ag_walk_grab(
+	struct xfs_inode	*ip)
+{
+	struct inode		*inode = VFS_I(ip);
+
+	/* nothing to sync during shutdown */
+	if (XFS_FORCED_SHUTDOWN(ip->i_mount))
+		return EFSCORRUPTED;
+
+	/* avoid new or reclaimable inodes. Leave for reclaim code to flush */
+	if (xfs_iflags_test(ip, XFS_INEW | XFS_IRECLAIMABLE | XFS_IRECLAIM))
+		return ENOENT;
+
+	/* If we can't grab the inode, it must on it's way to reclaim. */
+	if (!igrab(inode))
+		return ENOENT;
+
+	if (is_bad_inode(inode)) {
+		IRELE(ip);
+		return ENOENT;
+	}
+
+	/* inode is valid */
+	return 0;
+}
+
 
 STATIC int
 xfs_inode_ag_walk(
@@ -80,8 +107,14 @@ xfs_inode_ag_walk(
 		if (first_index < XFS_INO_TO_AGINO(mp, ip->i_ino))
 			done = 1;
 
-		/* execute releases pag->pag_ici_lock */
+		if (xfs_inode_ag_walk_grab(ip)) {
+			read_unlock(&pag->pag_ici_lock);
+			continue;
+		}
+		read_unlock(&pag->pag_ici_lock);
+
 		error = execute(ip, pag, flags);
+		IRELE(ip);
 		if (error == EAGAIN) {
 			skipped++;
 			continue;
@@ -128,40 +161,6 @@ xfs_inode_ag_iterator(
 	return XFS_ERROR(last_error);
 }
 
-/* must be called with pag_ici_lock held and releases it */
-int
-xfs_sync_inode_valid(
-	struct xfs_inode	*ip,
-	struct xfs_perag	*pag)
-{
-	struct inode		*inode = VFS_I(ip);
-	int			error = EFSCORRUPTED;
-
-	/* nothing to sync during shutdown */
-	if (XFS_FORCED_SHUTDOWN(ip->i_mount))
-		goto out_unlock;
-
-	/* avoid new or reclaimable inodes. Leave for reclaim code to flush */
-	error = ENOENT;
-	if (xfs_iflags_test(ip, XFS_INEW | XFS_IRECLAIMABLE | XFS_IRECLAIM))
-		goto out_unlock;
-
-	/* If we can't grab the inode, it must on it's way to reclaim. */
-	if (!igrab(inode))
-		goto out_unlock;
-
-	if (is_bad_inode(inode)) {
-		IRELE(ip);
-		goto out_unlock;
-	}
-
-	/* inode is valid */
-	error = 0;
-out_unlock:
-	read_unlock(&pag->pag_ici_lock);
-	return error;
-}
-
 STATIC int
 xfs_sync_inode_data(
 	struct xfs_inode	*ip,
@@ -172,10 +171,6 @@ xfs_sync_inode_data(
 	struct address_space *mapping = inode->i_mapping;
 	int			error = 0;
 
-	error = xfs_sync_inode_valid(ip, pag);
-	if (error)
-		return error;
-
 	if (!mapping_tagged(mapping, PAGECACHE_TAG_DIRTY))
 		goto out_wait;
 
@@ -192,7 +187,6 @@ xfs_sync_inode_data(
  out_wait:
 	if (flags & SYNC_WAIT)
 		xfs_ioend_wait(ip);
-	IRELE(ip);
 	return error;
 }
 
@@ -204,10 +198,6 @@ xfs_sync_inode_attr(
 {
 	int			error = 0;
 
-	error = xfs_sync_inode_valid(ip, pag);
-	if (error)
-		return error;
-
 	xfs_ilock(ip, XFS_ILOCK_SHARED);
 	if (xfs_inode_clean(ip))
 		goto out_unlock;
@@ -226,7 +216,6 @@ xfs_sync_inode_attr(
 
  out_unlock:
 	xfs_iunlock(ip, XFS_ILOCK_SHARED);
-	IRELE(ip);
 	return error;
 }
 

fs/xfs/quota/xfs_qm_syscalls.c

@@ -875,21 +875,14 @@ xfs_dqrele_inode(
 	struct xfs_perag	*pag,
 	int			flags)
 {
-	int			error;
-
 	/* skip quota inodes */
 	if (ip == ip->i_mount->m_quotainfo->qi_uquotaip ||
 	    ip == ip->i_mount->m_quotainfo->qi_gquotaip) {
 		ASSERT(ip->i_udquot == NULL);
 		ASSERT(ip->i_gdquot == NULL);
-		read_unlock(&pag->pag_ici_lock);
 		return 0;
 	}
 
-	error = xfs_sync_inode_valid(ip, pag);
-	if (error)
-		return error;
-
 	xfs_ilock(ip, XFS_ILOCK_EXCL);
 	if ((flags & XFS_UQUOTA_ACCT) && ip->i_udquot) {
 		xfs_qm_dqrele(ip->i_udquot);
@@ -900,8 +893,6 @@ xfs_dqrele_inode(
 		ip->i_gdquot = NULL;
 	}
 	xfs_iunlock(ip, XFS_ILOCK_EXCL);
-
-	IRELE(ip);
 	return 0;
 }