Btrfs-progs: remove unused variable and update btrfs-image man page

Remove unused variable in btrfs-image.c (update_super) and update man
page documentation about -r option. Running btrfsck on a restored
image produces missing chunk information. This is because by default,
btrfs-image fixes up chunk tree to use 1 stripe pointing to the
primary device. This in turns results in btrfsck making some noise.

$  ./mkfs.btrfs /dev/sdb2 -f
$  ./btrfs-image /dev/sdb2 btrfs_image_output
$  ./btrfs-image -r btrfs_image_output disk-image
$  ./btrfsck disk-image

Device extent[1, 29360128, 8388608] didn't find the relative chunk.
Device extent[1, 1111490560, 1073741824] didn't find the relative chunk.

Ideally btfsck should be updated to reflect this default behavior and
not through these messages, but it isn't harmful and can be done
later.

Signed-off-by: Rakesh Pandit <rakesh@tuxera.com>
Signed-off-by: David Sterba <dsterba@suse.cz>
Signed-off-by: Chris Mason <clm@fb.com>

diff --git a/btrfs-image.c b/btrfs-image.c
index c3a7fe5..cc8627c 100644 (file)
--- a/btrfs-image.c
+++ b/btrfs-image.c
@@ -1373,7 +1373,6 @@ static int update_super(u8 *buffer)
        u32 new_array_size = 0;
        u32 array_size;
        u32 cur = 0;
-       u32 new_cur = 0;
        u8 *ptr, *write_ptr;
        int old_num_stripes;
 
@@ -1390,7 +1389,6 @@ static int update_super(u8 *buffer)
                write_ptr += sizeof(*disk_key);
                ptr += sizeof(*disk_key);
                cur += sizeof(*disk_key);
-               new_cur += sizeof(*disk_key);
 
                if (key.type == BTRFS_CHUNK_ITEM_KEY) {
                        chunk = (struct btrfs_chunk *)ptr;
@@ -1406,7 +1404,6 @@ static int update_super(u8 *buffer)
                        memcpy(chunk->stripe.dev_uuid, super->dev_item.uuid,
                               BTRFS_UUID_SIZE);
                        new_array_size += sizeof(*chunk);
-                       new_cur += sizeof(*chunk);
                } else {
                        fprintf(stderr, "Bogus key in the sys chunk array "
                                "%d\n", key.type);

diff --git a/man/btrfs-image.8.in b/man/btrfs-image.8.in
index d5ba594..3f51f3f 100644 (file)
--- a/man/btrfs-image.8.in
+++ b/man/btrfs-image.8.in
@@ -17,7 +17,10 @@ is the image file that btrfs-image creates. When used with \fB-r\fP option,
 .SH OPTIONS
 .TP
 \fB\-r\fP
-restore metadump image.
+Restore metadump image. By default, this fixes super's chunk tree, by
+using 1 stripe pointing to primary device, so that file system can be
+restored by running tree log reply if possible. To restore without
+changing number of stripes in chunk tree check \fB-o\fP option.
 .TP
 \fB\-c\fR \fIvalue\fP
 compression level (0 ~ 9).