[PATCH v4 11/17] xfs: Add xfs_attr3_leaf helper functions

[Allison Collins <allison.henderson@oracle.com>]

And new helper functions xfs_attr3_leaf_flag_is_set and
xfs_attr3_leaf_flagsflipped.  These routines check to see
if xfs_attr3_leaf_setflag or xfs_attr3_leaf_flipflags have
already been run.  We will need this later for delayed
attributes since routines may be recalled several times
when -EAGAIN is returned.

Signed-off-by: Allison Collins <allison.henderson@oracle.com>
---
 fs/xfs/libxfs/xfs_attr_leaf.c | 94 +++++++++++++++++++++++++++++++++++++++++++
 fs/xfs/libxfs/xfs_attr_leaf.h |  2 +
 2 files changed, 96 insertions(+)

diff --git a/fs/xfs/libxfs/xfs_attr_leaf.c b/fs/xfs/libxfs/xfs_attr_leaf.c
index 42c037e..023c616 100644
--- a/fs/xfs/libxfs/xfs_attr_leaf.c
+++ b/fs/xfs/libxfs/xfs_attr_leaf.c
@@ -2809,6 +2809,40 @@ xfs_attr3_leaf_clearflag(
 }
 
 /*
+ * Check if the INCOMPLETE flag on an entry in a leaf block is set.  This
+ * function can be used to check if xfs_attr3_leaf_setflag has already been
+ * called.  The INCOMPLETE flag is used during attr rename operations to mark
+ * entries that are being renamed. Since renames should be atomic, only one of
+ * them should appear as a completed attribute.
+ *
+ * isset is set to true if the flag is set or false otherwise
+ */
+int
+xfs_attr3_leaf_flag_is_set(
+	struct xfs_da_args		*args,
+	bool				*isset)
+{
+	struct xfs_attr_leafblock	*leaf;
+	struct xfs_attr_leaf_entry	*entry;
+	struct xfs_buf			*bp;
+	struct xfs_inode		*dp = args->dp;
+	int				error = 0;
+
+	error = xfs_attr3_leaf_read(args->trans, dp, args->blkno,
+				    XFS_DABUF_MAP_NOMAPPING, &bp);
+	if (error)
+		return error;
+
+	leaf = bp->b_addr;
+	entry = &xfs_attr3_leaf_entryp(leaf)[args->index];
+
+	*isset = ((entry->flags & XFS_ATTR_INCOMPLETE) != 0);
+	xfs_trans_brelse(args->trans, bp);
+
+	return 0;
+}
+
+/*
  * Set the INCOMPLETE flag on an entry in a leaf block.
  */
 int
@@ -2972,3 +3006,63 @@ xfs_attr3_leaf_flipflags(
 
 	return error;
 }
+
+/*
+ * On a leaf entry, check to see if the INCOMPLETE flag is cleared
+ * in args->blkno/index and set in args->blkno2/index2.  Note that they could be
+ * in different blocks, or in the same block.  This function can be used to
+ * check if xfs_attr3_leaf_flipflags has already been called.  The INCOMPLETE
+ * flag is used during attr rename operations to mark entries that are being
+ * renamed. Since renames should be atomic, only one of them should appear as a
+ * completed attribute.
+ *
+ * isflipped is set to true if flags are flipped or false otherwise
+ */
+int
+xfs_attr3_leaf_flagsflipped(
+	struct xfs_da_args		*args,
+	bool				*isflipped)
+{
+	struct xfs_attr_leafblock	*leaf1;
+	struct xfs_attr_leafblock	*leaf2;
+	struct xfs_attr_leaf_entry	*entry1;
+	struct xfs_attr_leaf_entry	*entry2;
+	struct xfs_buf			*bp1;
+	struct xfs_buf			*bp2;
+	struct xfs_inode		*dp = args->dp;
+	int				error = 0;
+
+	/*
+	 * Read the block containing the "old" attr
+	 */
+	error = xfs_attr3_leaf_read(args->trans, dp, args->blkno,
+				    XFS_DABUF_MAP_NOMAPPING, &bp1);
+	if (error)
+		return error;
+
+	/*
+	 * Read the block containing the "new" attr, if it is different
+	 */
+	if (args->blkno2 != args->blkno) {
+		error = xfs_attr3_leaf_read(args->trans, args->dp, args->blkno2,
+					   -1, &bp2);
+		if (error)
+			return error;
+	} else {
+		bp2 = bp1;
+	}
+
+	leaf1 = bp1->b_addr;
+	entry1 = &xfs_attr3_leaf_entryp(leaf1)[args->index];
+
+	leaf2 = bp2->b_addr;
+	entry2 = &xfs_attr3_leaf_entryp(leaf2)[args->index2];
+
+	*isflipped = (((entry1->flags & XFS_ATTR_INCOMPLETE) == 0) &&
+		      (entry2->flags & XFS_ATTR_INCOMPLETE));
+
+	xfs_trans_brelse(args->trans, bp1);
+	xfs_trans_brelse(args->trans, bp2);
+
+	return 0;
+}
diff --git a/fs/xfs/libxfs/xfs_attr_leaf.h b/fs/xfs/libxfs/xfs_attr_leaf.h
index e108b37..12283cf 100644
--- a/fs/xfs/libxfs/xfs_attr_leaf.h
+++ b/fs/xfs/libxfs/xfs_attr_leaf.h
@@ -57,7 +57,9 @@ int	xfs_attr3_leaf_to_shortform(struct xfs_buf *bp,
 				   struct xfs_da_args *args, int forkoff);
 int	xfs_attr3_leaf_clearflag(struct xfs_da_args *args);
 int	xfs_attr3_leaf_setflag(struct xfs_da_args *args);
+int	xfs_attr3_leaf_flag_is_set(struct xfs_da_args *args, bool *isset);
 int	xfs_attr3_leaf_flipflags(struct xfs_da_args *args);
+int	xfs_attr3_leaf_flagsflipped(struct xfs_da_args *args, bool *isflipped);
 
 /*
  * Routines used for growing the Btree.
-- 
2.7.4