[PATCH 06/29] fuse2fs: support XATTR_CREATE/REPLACE in setxattr

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

From: Darrick J. Wong <djwong@xxxxxxxxxx>

Fix the setxattr implementation to support the create and replace flags
instead of performing an upsert regardless of inputs.

Cc: <linux-ext4@xxxxxxxxxxxxxxx> # v1.43
Fixes: 81cbf1ef4f5dab ("misc: add fuse2fs, a FUSE server for e2fsprogs")
Signed-off-by: "Darrick J. Wong" <djwong@xxxxxxxxxx>
---
 misc/fuse2fs.c |   30 +++++++++++++++++++++++++++++-
 1 file changed, 29 insertions(+), 1 deletion(-)


diff --git a/misc/fuse2fs.c b/misc/fuse2fs.c
index 40bb223d50c4fe..33f72cf08f7b3a 100644
--- a/misc/fuse2fs.c
+++ b/misc/fuse2fs.c
@@ -2507,7 +2507,7 @@ static int op_listxattr(const char *path, char *names, size_t len)
 
 static int op_setxattr(const char *path EXT2FS_ATTR((unused)),
 		       const char *key, const char *value,
-		       size_t len, int flags EXT2FS_ATTR((unused)))
+		       size_t len, int flags)
 {
 	struct fuse_context *ctxt = fuse_get_context();
 	struct fuse2fs *ff = (struct fuse2fs *)ctxt->private_data;
@@ -2517,6 +2517,9 @@ static int op_setxattr(const char *path EXT2FS_ATTR((unused)),
 	errcode_t err;
 	int ret = 0;
 
+	if (flags & ~(XATTR_CREATE | XATTR_REPLACE))
+		return -EOPNOTSUPP;
+
 	FUSE2FS_CHECK_CONTEXT(ff);
 	fs = ff->fs;
 	pthread_mutex_lock(&ff->bfl);
@@ -2551,6 +2554,31 @@ static int op_setxattr(const char *path EXT2FS_ATTR((unused)),
 		goto out2;
 	}
 
+	if (flags & (XATTR_CREATE | XATTR_REPLACE)) {
+		void *buf;
+		size_t buflen;
+
+		err = ext2fs_xattr_get(h, key, &buf, &buflen);
+		switch (err) {
+		case EXT2_ET_EA_KEY_NOT_FOUND:
+			if (flags & XATTR_REPLACE) {
+				ret = -ENODATA;
+				goto out2;
+			}
+			break;
+		case 0:
+			ext2fs_free_mem(&buf);
+			if (flags & XATTR_CREATE) {
+				ret = -EEXIST;
+				goto out2;
+			}
+			break;
+		default:
+			ret = translate_error(fs, ino, err);
+			goto out2;
+		}
+	}
+
 	err = ext2fs_xattr_set(h, key, value, len);
 	if (err) {
 		ret = translate_error(fs, ino, err);