[PATCH 044/115] xfs: make attr removal an explicit operation

["Darrick J. Wong" <djwong@xxxxxxxxxx>]

From: Darrick J. Wong <djwong@xxxxxxxxxx>

Source kernel commit: c27411d4c640037d70e2fa5751616e175e52ca5e

Parent pointers match attrs on name+value, unlike everything else which
matches on only the name.  Therefore, we cannot keep using the heuristic
that !value means remove.  Make this an explicit operation code.

Signed-off-by: Darrick J. Wong <djwong@xxxxxxxxxx>
Reviewed-by: Christoph Hellwig <hch@xxxxxx>
---
 db/attrset.c      |    4 ++--
 libxfs/xfs_attr.c |   19 ++++++++++---------
 libxfs/xfs_attr.h |    3 ++-
 3 files changed, 14 insertions(+), 12 deletions(-)


diff --git a/db/attrset.c b/db/attrset.c
index 736482fea..a59d5473e 100644
--- a/db/attrset.c
+++ b/db/attrset.c
@@ -69,7 +69,7 @@ attr_set_f(
 {
 	struct xfs_da_args	args = { };
 	char			*sp;
-	enum xfs_attr_update	op = XFS_ATTRUPDATE_UPSERTR;
+	enum xfs_attr_update	op = XFS_ATTRUPDATE_UPSERT;
 	int			c;
 
 	if (cur_typ == NULL) {
@@ -247,7 +247,7 @@ attr_remove_f(
 		goto out;
 	}
 
-	if (libxfs_attr_set(&args, XFS_ATTRUPDATE_UPSERTR)) {
+	if (libxfs_attr_set(&args, XFS_ATTRUPDATE_REMOVE)) {
 		dbprintf(_("failed to remove attr %s from inode %llu\n"),
 			(unsigned char *)args.name,
 			(unsigned long long)iocur_top->ino);
diff --git a/libxfs/xfs_attr.c b/libxfs/xfs_attr.c
index 9a6787624..5249f9be0 100644
--- a/libxfs/xfs_attr.c
+++ b/libxfs/xfs_attr.c
@@ -914,10 +914,6 @@ xfs_attr_defer_add(
 	trace_xfs_attr_defer_add(new->xattri_dela_state, args->dp);
 }
 
-/*
- * Note: If args->value is NULL the attribute will be removed, just like the
- * Linux ->setattr API.
- */
 int
 xfs_attr_set(
 	struct xfs_da_args	*args,
@@ -953,7 +949,10 @@ xfs_attr_set(
 	args->op_flags = XFS_DA_OP_OKNOENT |
 					(args->op_flags & XFS_DA_OP_LOGGED);
 
-	if (args->value) {
+	switch (op) {
+	case XFS_ATTRUPDATE_UPSERT:
+	case XFS_ATTRUPDATE_CREATE:
+	case XFS_ATTRUPDATE_REPLACE:
 		XFS_STATS_INC(mp, xs_attr_set);
 		args->total = xfs_attr_calc_size(args, &local);
 
@@ -973,9 +972,11 @@ xfs_attr_set(
 
 		if (!local)
 			rmt_blks = xfs_attr3_rmt_blocks(mp, args->valuelen);
-	} else {
+		break;
+	case XFS_ATTRUPDATE_REMOVE:
 		XFS_STATS_INC(mp, xs_attr_remove);
 		rmt_blks = xfs_attr3_rmt_blocks(mp, XFS_XATTR_SIZE_MAX);
+		break;
 	}
 
 	/*
@@ -987,7 +988,7 @@ xfs_attr_set(
 	if (error)
 		return error;
 
-	if (args->value || xfs_inode_hasattr(dp)) {
+	if (op != XFS_ATTRUPDATE_REMOVE || xfs_inode_hasattr(dp)) {
 		error = xfs_iext_count_may_overflow(dp, XFS_ATTR_FORK,
 				XFS_IEXT_ATTR_MANIP_CNT(rmt_blks));
 		if (error == -EFBIG)
@@ -1000,7 +1001,7 @@ xfs_attr_set(
 	error = xfs_attr_lookup(args);
 	switch (error) {
 	case -EEXIST:
-		if (!args->value) {
+		if (op == XFS_ATTRUPDATE_REMOVE) {
 			/* if no value, we are performing a remove operation */
 			xfs_attr_defer_add(args, XFS_ATTRI_OP_FLAGS_REMOVE);
 			break;
@@ -1013,7 +1014,7 @@ xfs_attr_set(
 		break;
 	case -ENOATTR:
 		/* Can't remove what isn't there. */
-		if (!args->value)
+		if (op == XFS_ATTRUPDATE_REMOVE)
 			goto out_trans_cancel;
 
 		/* Pure replace fails if no existing attr to replace. */
diff --git a/libxfs/xfs_attr.h b/libxfs/xfs_attr.h
index 228360f7c..c8005f521 100644
--- a/libxfs/xfs_attr.h
+++ b/libxfs/xfs_attr.h
@@ -546,7 +546,8 @@ int xfs_attr_get_ilocked(struct xfs_da_args *args);
 int xfs_attr_get(struct xfs_da_args *args);
 
 enum xfs_attr_update {
-	XFS_ATTRUPDATE_UPSERTR,	/* set/remove value, replace any existing attr */
+	XFS_ATTRUPDATE_REMOVE,	/* remove attr */
+	XFS_ATTRUPDATE_UPSERT,	/* set value, replace any existing attr */
 	XFS_ATTRUPDATE_CREATE,	/* set value, fail if attr already exists */
 	XFS_ATTRUPDATE_REPLACE,	/* set value, fail if attr does not exist */
 };