xfs: separate out initial attr_set states

We current use XFS_DAS_UNINIT for several steps in the attr_set
state machine. We use it for setting shortform xattrs, converting
from shortform to leaf, leaf add, leaf-to-node and leaf add. All of
these things are essentially known before we start the state machine
iterating, so we really should separate them out:

XFS_DAS_SF_ADD:
	- tries to do a shortform add
	- on success -> done
	- on ENOSPC converts to leaf, -> XFS_DAS_LEAF_ADD
	- on error, dies.

XFS_DAS_LEAF_ADD:
	- tries to do leaf add
	- on success:
		- inline attr -> done
		- remote xattr || REPLACE -> XFS_DAS_FOUND_LBLK
	- on ENOSPC converts to node, -> XFS_DAS_NODE_ADD
	- on error, dies

XFS_DAS_NODE_ADD:
	- tries to do node add
	- on success:
		- inline attr -> done
		- remote xattr || REPLACE -> XFS_DAS_FOUND_NBLK
	- on error, dies

This makes it easier to understand how the state machine starts
up and sets us up on the path to further state machine
simplifications.

This also converts the DAS state tracepoints to use strings rather
than numbers, as converting between enums and numbers requires
manual counting rather than just reading the name.

This also introduces a XFS_DAS_DONE state so that we can trace
successful operation completions easily.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Allison Henderson<allison.henderson@oracle.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Dave Chinner <david@fromorbit.com>

1 files changed, 76 insertions, 13 deletions

diff --git a/fs/xfs/libxfs/xfs_attr.h b/fs/xfs/libxfs/xfs_attr.h
index c9c867e3406c..bbbc964f4e3c 100644
--- a/fs/xfs/libxfs/xfs_attr.h
+++ b/fs/xfs/libxfs/xfs_attr.h
@@ -443,21 +443,44 @@ struct xfs_attr_list_context {
  * to where it was and resume executing where it left off.
  */
 enum xfs_delattr_state {
-	XFS_DAS_UNINIT		= 0,  /* No state has been set yet */
-	XFS_DAS_RMTBLK,		      /* Removing remote blks */
-	XFS_DAS_RM_NAME,	      /* Remove attr name */
-	XFS_DAS_RM_SHRINK,	      /* We are shrinking the tree */
-	XFS_DAS_FOUND_LBLK,	      /* We found leaf blk for attr */
-	XFS_DAS_FOUND_NBLK,	      /* We found node blk for attr */
-	XFS_DAS_FLIP_LFLAG,	      /* Flipped leaf INCOMPLETE attr flag */
-	XFS_DAS_RM_LBLK,	      /* A rename is removing leaf blocks */
-	XFS_DAS_RD_LEAF,	      /* Read in the new leaf */
-	XFS_DAS_ALLOC_NODE,	      /* We are allocating node blocks */
-	XFS_DAS_FLIP_NFLAG,	      /* Flipped node INCOMPLETE attr flag */
-	XFS_DAS_RM_NBLK,	      /* A rename is removing node blocks */
-	XFS_DAS_CLR_FLAG,	      /* Clear incomplete flag */
+	XFS_DAS_UNINIT		= 0,	/* No state has been set yet */
+	XFS_DAS_SF_ADD,			/* Initial shortform set iter state */
+	XFS_DAS_LEAF_ADD,		/* Initial leaf form set iter state */
+	XFS_DAS_NODE_ADD,		/* Initial node form set iter state */
+	XFS_DAS_RMTBLK,			/* Removing remote blks */
+	XFS_DAS_RM_NAME,		/* Remove attr name */
+	XFS_DAS_RM_SHRINK,		/* We are shrinking the tree */
+	XFS_DAS_FOUND_LBLK,		/* We found leaf blk for attr */
+	XFS_DAS_FOUND_NBLK,		/* We found node blk for attr */
+	XFS_DAS_FLIP_LFLAG,		/* Flipped leaf INCOMPLETE attr flag */
+	XFS_DAS_RM_LBLK,		/* A rename is removing leaf blocks */
+	XFS_DAS_RD_LEAF,		/* Read in the new leaf */
+	XFS_DAS_ALLOC_NODE,		/* We are allocating node blocks */
+	XFS_DAS_FLIP_NFLAG,		/* Flipped node INCOMPLETE attr flag */
+	XFS_DAS_RM_NBLK,		/* A rename is removing node blocks */
+	XFS_DAS_CLR_FLAG,		/* Clear incomplete flag */
+	XFS_DAS_DONE,			/* finished operation */
 };
 
+#define XFS_DAS_STRINGS	\
+	{ XFS_DAS_UNINIT,	"XFS_DAS_UNINIT" }, \
+	{ XFS_DAS_SF_ADD,	"XFS_DAS_SF_ADD" }, \
+	{ XFS_DAS_LEAF_ADD,	"XFS_DAS_LEAF_ADD" }, \
+	{ XFS_DAS_NODE_ADD,	"XFS_DAS_NODE_ADD" }, \
+	{ XFS_DAS_RMTBLK,	"XFS_DAS_RMTBLK" }, \
+	{ XFS_DAS_RM_NAME,	"XFS_DAS_RM_NAME" }, \
+	{ XFS_DAS_RM_SHRINK,	"XFS_DAS_RM_SHRINK" }, \
+	{ XFS_DAS_FOUND_LBLK,	"XFS_DAS_FOUND_LBLK" }, \
+	{ XFS_DAS_FOUND_NBLK,	"XFS_DAS_FOUND_NBLK" }, \
+	{ XFS_DAS_FLIP_LFLAG,	"XFS_DAS_FLIP_LFLAG" }, \
+	{ XFS_DAS_RM_LBLK,	"XFS_DAS_RM_LBLK" }, \
+	{ XFS_DAS_RD_LEAF,	"XFS_DAS_RD_LEAF" }, \
+	{ XFS_DAS_ALLOC_NODE,	"XFS_DAS_ALLOC_NODE" }, \
+	{ XFS_DAS_FLIP_NFLAG,	"XFS_DAS_FLIP_NFLAG" }, \
+	{ XFS_DAS_RM_NBLK,	"XFS_DAS_RM_NBLK" }, \
+	{ XFS_DAS_CLR_FLAG,	"XFS_DAS_CLR_FLAG" }, \
+	{ XFS_DAS_DONE,		"XFS_DAS_DONE" }
+
 /*
  * Defines for xfs_attr_item.xattri_flags
  */
@@ -530,4 +553,44 @@ void xfs_attri_destroy_cache(void);
 int __init xfs_attrd_init_cache(void);
 void xfs_attrd_destroy_cache(void);
 
+/*
+ * Check to see if the attr should be upgraded from non-existent or shortform to
+ * single-leaf-block attribute list.
+ */
+static inline bool
+xfs_attr_is_shortform(
+	struct xfs_inode    *ip)
+{
+	return ip->i_afp->if_format == XFS_DINODE_FMT_LOCAL ||
+	       (ip->i_afp->if_format == XFS_DINODE_FMT_EXTENTS &&
+		ip->i_afp->if_nextents == 0);
+}
+
+static inline enum xfs_delattr_state
+xfs_attr_init_add_state(struct xfs_da_args *args)
+{
+
+	/*
+	 * When called from the completion of a attr remove to determine the
+	 * next state, the attribute fork may be null. This can occur only occur
+	 * on a pure remove, but we grab the next state before we check if a
+	 * replace operation is being performed. If we are called from any other
+	 * context, i_afp is guaranteed to exist. Hence if the attr fork is
+	 * null, we were called from a pure remove operation and so we are done.
+	 */
+	if (!args->dp->i_afp)
+		return XFS_DAS_DONE;
+	if (xfs_attr_is_shortform(args->dp))
+		return XFS_DAS_SF_ADD;
+	if (xfs_attr_is_leaf(args->dp))
+		return XFS_DAS_LEAF_ADD;
+	return XFS_DAS_NODE_ADD;
+}
+
+static inline enum xfs_delattr_state
+xfs_attr_init_replace_state(struct xfs_da_args *args)
+{
+	return xfs_attr_init_add_state(args);
+}
+
 #endif	/* __XFS_ATTR_H__ */