gfs2: further simplify gfs2_evict_inode with new func evict_should_delete

This patch further simplifies function gfs2_evict_inode() by adding a
new function evict_should_delete. The function may also lock the inode
glock.
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>

fs/gfs2/super.c

@@ -44,6 +44,12 @@
 #include "xattr.h"
 #include "lops.h"
 
+enum dinode_demise {
+	SHOULD_DELETE_DINODE,
+	SHOULD_NOT_DELETE_DINODE,
+	SHOULD_DEFER_EVICTION,
+};
+
 /**
  * gfs2_jindex_free - Clear all the journal index information
  * @sdp: The GFS2 superblock
@@ -1310,6 +1316,73 @@ static bool gfs2_upgrade_iopen_glock(struct inode *inode)
 	return true;
 }
 
+/**
+ * evict_should_delete - determine whether the inode is eligible for deletion
+ * @inode: The inode to evict
+ *
+ * This function determines whether the evicted inode is eligible to be deleted
+ * and locks the inode glock.
+ *
+ * Returns: the fate of the dinode
+ */
+static enum dinode_demise evict_should_delete(struct inode *inode,
+					      struct gfs2_holder *gh)
+{
+	struct gfs2_inode *ip = GFS2_I(inode);
+	struct super_block *sb = inode->i_sb;
+	struct gfs2_sbd *sdp = sb->s_fs_info;
+	int ret;
+
+	if (test_bit(GIF_ALLOC_FAILED, &ip->i_flags)) {
+		BUG_ON(!gfs2_glock_is_locked_by_me(ip->i_gl));
+		goto should_delete;
+	}
+
+	if (test_bit(GIF_DEFERRED_DELETE, &ip->i_flags))
+		return SHOULD_DEFER_EVICTION;
+
+	/* Deletes should never happen under memory pressure anymore.  */
+	if (WARN_ON_ONCE(current->flags & PF_MEMALLOC))
+		return SHOULD_DEFER_EVICTION;
+
+	/* Must not read inode block until block type has been verified */
+	ret = gfs2_glock_nq_init(ip->i_gl, LM_ST_EXCLUSIVE, GL_SKIP, gh);
+	if (unlikely(ret)) {
+		glock_clear_object(ip->i_iopen_gh.gh_gl, ip);
+		ip->i_iopen_gh.gh_flags |= GL_NOCACHE;
+		gfs2_glock_dq_uninit(&ip->i_iopen_gh);
+		return SHOULD_DEFER_EVICTION;
+	}
+
+	if (gfs2_inode_already_deleted(ip->i_gl, ip->i_no_formal_ino))
+		return SHOULD_NOT_DELETE_DINODE;
+	ret = gfs2_check_blk_type(sdp, ip->i_no_addr, GFS2_BLKST_UNLINKED);
+	if (ret)
+		return SHOULD_NOT_DELETE_DINODE;
+
+	if (test_bit(GIF_INVALID, &ip->i_flags)) {
+		ret = gfs2_inode_refresh(ip);
+		if (ret)
+			return SHOULD_NOT_DELETE_DINODE;
+	}
+
+	/*
+	 * The inode may have been recreated in the meantime.
+	 */
+	if (inode->i_nlink)
+		return SHOULD_NOT_DELETE_DINODE;
+
+should_delete:
+	if (gfs2_holder_initialized(&ip->i_iopen_gh) &&
+	    test_bit(HIF_HOLDER, &ip->i_iopen_gh.gh_iflags)) {
+		if (!gfs2_upgrade_iopen_glock(inode)) {
+			gfs2_holder_uninit(&ip->i_iopen_gh);
+			return SHOULD_NOT_DELETE_DINODE;
+		}
+	}
+	return SHOULD_DELETE_DINODE;
+}
+
 /**
  * evict_unlinked_inode - delete the pieces of an unlinked evicted inode
  * @inode: The inode to evict
@@ -1387,54 +1460,13 @@ static void gfs2_evict_inode(struct inode *inode)
 	if (inode->i_nlink || sb_rdonly(sb))
 		goto out;
 
-	if (test_bit(GIF_ALLOC_FAILED, &ip->i_flags)) {
-		BUG_ON(!gfs2_glock_is_locked_by_me(ip->i_gl));
 	gfs2_holder_mark_uninitialized(&gh);
-		goto out_delete;
-	}
-
-	if (test_bit(GIF_DEFERRED_DELETE, &ip->i_flags))
+	ret = evict_should_delete(inode, &gh);
+	if (ret == SHOULD_DEFER_EVICTION)
 		goto out;
-
-	/* Deletes should never happen under memory pressure anymore.  */
-	if (WARN_ON_ONCE(current->flags & PF_MEMALLOC))
-		goto out;
-
-	/* Must not read inode block until block type has been verified */
-	ret = gfs2_glock_nq_init(ip->i_gl, LM_ST_EXCLUSIVE, GL_SKIP, &gh);
-	if (unlikely(ret)) {
-		glock_clear_object(ip->i_iopen_gh.gh_gl, ip);
-		ip->i_iopen_gh.gh_flags |= GL_NOCACHE;
-		gfs2_glock_dq_uninit(&ip->i_iopen_gh);
-		goto out;
-	}
-
-	if (gfs2_inode_already_deleted(ip->i_gl, ip->i_no_formal_ino))
-		goto out_truncate;
-	ret = gfs2_check_blk_type(sdp, ip->i_no_addr, GFS2_BLKST_UNLINKED);
-	if (ret)
-		goto out_truncate;
-
-	if (test_bit(GIF_INVALID, &ip->i_flags)) {
-		ret = gfs2_inode_refresh(ip);
-		if (ret)
+	if (ret == SHOULD_NOT_DELETE_DINODE)
 		goto out_truncate;
-	}
 
-	/*
-	 * The inode may have been recreated in the meantime.
-	 */
-	if (inode->i_nlink)
-		goto out_truncate;
-
-out_delete:
-	if (gfs2_holder_initialized(&ip->i_iopen_gh) &&
-	    test_bit(HIF_HOLDER, &ip->i_iopen_gh.gh_iflags)) {
-		if (!gfs2_upgrade_iopen_glock(inode)) {
-			gfs2_holder_uninit(&ip->i_iopen_gh);
-			goto out_truncate;
-		}
-	}
 	ret = evict_unlinked_inode(inode);
 	goto out_unlock;