btrfs-progs framework to add support to label the subvol and
snapshots. This patch is for the ioctl-way to write label
to the subvol and snapshot. (the other way is to use attribute
if then only this patch has to be backed out in btrfs-progs
and replace with the patch titled
Btrfs-progs: add attribute label for subvol and snapshot)
Signed-off-by: Anand Jain <anand.jain@xxxxxxxxxx>
---
btrfslabel.c | 45 +++++++++++++++++++++++++++++++++++++++++++++
btrfslabel.h | 4 +++-
ctree.h | 4 +++-
ioctl.h | 2 ++
print-tree.c | 2 ++
5 files changed, 55 insertions(+), 2 deletions(-)
diff --git a/btrfslabel.c b/btrfslabel.c
index a421a8b..b3ad540 100644
--- a/btrfslabel.c
+++ b/btrfslabel.c
@@ -126,3 +126,48 @@ int set_label(char *btrfs_dev, char *nLabel)
}
return change_label_unmounted(btrfs_dev, nLabel);
}
+
+int get_subvol_label(char *subvol, char *labelp)
+{
+ int fd, e=0;
+
+ fd = open_file_or_dir(subvol);
+
+ if(ioctl(fd, BTRFS_IOC_SUBVOL_GETLABEL, labelp) < 0) {
+ e = errno;
+ fprintf(stderr, "ERROR: get subvol label failed, %s\n",
+ strerror(e));
+ close(fd);
+ return -e;
+ }
+ labelp[BTRFS_LABEL_SIZE] = '\0';
+ if (!strlen(labelp))
+ return -1;
+ close(fd);
+ return 0;
+}
+
+int set_subvol_label(char *subvol, char *labelp)
+{
+ int fd, e=0;
+ char label[BTRFS_SUBVOL_LABEL_SIZE+1];
+
+ if (strlen(labelp) > BTRFS_SUBVOL_LABEL_SIZE) {
+ fprintf(stderr, "ERROR: Subvol label is more than max length %d\n",
+ BTRFS_SUBVOL_LABEL_SIZE);
+ return -1;
+ }
+ memset(label, 0, BTRFS_SUBVOL_LABEL_SIZE+1);
+ strcpy(label, labelp);
+ fd = open_file_or_dir(subvol);
+
+ if(ioctl(fd, BTRFS_IOC_SUBVOL_SETLABEL, label) < 0) {
+ e = errno;
+ fprintf(stderr, "ERROR: set subvol label failed, %s\n",
+ strerror(e));
+ close(fd);
+ return -e;
+ }
+ close(fd);
+ return 0;
+}
diff --git a/btrfslabel.h b/btrfslabel.h
index abf43ad..1abc483 100644
--- a/btrfslabel.h
+++ b/btrfslabel.h
@@ -2,4 +2,6 @@
int get_label(char *btrfs_dev);
-int set_label(char *btrfs_dev, char *nLabel);
\ No newline at end of file
+int set_label(char *btrfs_dev, char *nLabel);
+int get_subvol_label(char *subvol, char *labelp);
+int set_subvol_label(char *subvol, char *labelp);
diff --git a/ctree.h b/ctree.h
index 12f8fe3..bacb7d1 100644
--- a/ctree.h
+++ b/ctree.h
@@ -332,6 +332,7 @@ struct btrfs_header {
*/
#define BTRFS_SYSTEM_CHUNK_ARRAY_SIZE 2048
#define BTRFS_LABEL_SIZE 256
+#define BTRFS_SUBVOL_LABEL_SIZE 32
/*
* just in case we somehow lose the roots and are not able to mount,
@@ -721,7 +722,8 @@ struct btrfs_root_item {
struct btrfs_timespec otime;
struct btrfs_timespec stime;
struct btrfs_timespec rtime;
- __le64 reserved[8]; /* for future */
+ char label[BTRFS_SUBVOL_LABEL_SIZE];
+ __le64 reserved[4]; /* for future */
} __attribute__ ((__packed__));
/*
diff --git a/ioctl.h b/ioctl.h
index 3e7e451..4cbae3a 100644
--- a/ioctl.h
+++ b/ioctl.h
@@ -524,6 +524,8 @@ struct btrfs_ioctl_clone_range_args {
struct btrfs_ioctl_get_dev_stats)
#define BTRFS_IOC_DEV_REPLACE _IOWR(BTRFS_IOCTL_MAGIC, 53, \
struct btrfs_ioctl_dev_replace_args)
+#define BTRFS_IOC_SUBVOL_GETLABEL _IOWR(BTRFS_IOCTL_MAGIC, 55, __u64)
+#define BTRFS_IOC_SUBVOL_SETLABEL _IOW(BTRFS_IOCTL_MAGIC, 56, __u64)
#ifdef __cplusplus
}
diff --git a/print-tree.c b/print-tree.c
index c9e891b..3d097dd 100644
--- a/print-tree.c
+++ b/print-tree.c
@@ -366,6 +366,8 @@ static void print_root(struct extent_buffer *leaf, int slot)
btrfs_root_stransid(&root_item),
btrfs_root_rtransid(&root_item));
}
+ if (strlen(root_item.label))
+ printf("\t\tlabel %s\n", root_item.label);
}
if (btrfs_root_refs(&root_item) == 0) {
struct btrfs_key drop_key;
--
1.8.1.227.g44fe835
--
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