[PATCH v2] btrfs-progs: allow "none" to disable compression for convenience

[Satoru Takeuchi <satoru.takeuchi@gmail.com>]

At Sun, 17 Sep 2017 14:08:40 +0100,
Mike Fleetwood wrote:
> 
> On 17 September 2017 at 01:36, Satoru Takeuchi
> <satoru.takeuchi@gmail.com> wrote:
> > It's messy to use "" to disable compression. Introduce the new value "no"
> > which can also be used for this purpose.
> 
> From an English language point of view, "none" would be better.  None
> says the absence of, where as no is more general negative.

Thank you for your comment. How about is it?

---
It's messy to use "" to disable compression. Introduce the new value "none"
which can also be used for this purpose.

Signed-off-by: Satoru Takeuchi <satoru.takeuchi@gmail.com>
---
 Documentation/btrfs-property.asciidoc | 2 +-
 props.c                               | 6 ++++--
 2 files changed, 5 insertions(+), 3 deletions(-)

diff --git a/Documentation/btrfs-property.asciidoc b/Documentation/btrfs-property.asciidoc
index 7ed6a7d..786af9b 100644
--- a/Documentation/btrfs-property.asciidoc
+++ b/Documentation/btrfs-property.asciidoc
@@ -43,7 +43,7 @@ read-only flag of subvolume: true or false
 label::::
 label of device
 compression::::
-compression setting for an inode: lzo, zlib, zstd, or "" (empty string)
+compression setting for an inode: lzo, zlib, zstd, none, or "" (empty string). Both none and "" are for disabling compression.
 
 *list* [-t <type>] <object>::
 Lists available properties with their descriptions for the given object.
diff --git a/props.c b/props.c
index a7e3e96..8d85181 100644
--- a/props.c
+++ b/props.c
@@ -142,9 +142,11 @@ static int prop_compression(enum prop_object_type type,
 	memcpy(xattr_name + XATTR_BTRFS_PREFIX_LEN, name, strlen(name));
 	xattr_name[XATTR_BTRFS_PREFIX_LEN + strlen(name)] = '\0';
 
-	if (value)
+	if (value) {
+		if (!strcmp(value, "none"))
+			value = "";
 		sret = fsetxattr(fd, xattr_name, value, strlen(value), 0);
-	else
+	} else
 		sret = fgetxattr(fd, xattr_name, NULL, 0);
 	if (sret < 0) {
 		ret = -errno;
-- 
2.7.4