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authorAnand Jain <anand.jain@oracle.com>2015-09-15 16:46:22 +0800
committerDavid Sterba <dsterba@suse.com>2015-10-02 17:52:10 +0200
commit94789777b9e8f350ba815b07baa5383e99cd1944 (patch)
treec7874b6f83c52ecbac8dd8f9747004963004ae20
parent3276a9f519155486383e20958e0c5eb55d4c0b4f (diff)
btrfs-progs: provide fail safe for BTRFS_IOC_GET_FSLABEL ioctl
Old kernels before 3.9 do not provide ioctl BTRFS_IOC_GET_FSLABEL. So we need to provide a fail safe logic for btrfs-progs running on those kernel. In this patch when get_label_mounted() fails on the old kernel it will fail back to the old method and uses get_label_unmounted(), where it will read from the disk directly. Signed-off-by: Anand Jain <anand.jain@oracle.com> Signed-off-by: David Sterba <dsterba@suse.com>
-rw-r--r--cmds-filesystem.c8
-rw-r--r--utils.c18
-rw-r--r--utils.h1
3 files changed, 17 insertions, 10 deletions
diff --git a/cmds-filesystem.c b/cmds-filesystem.c
index 8822695e..09cb37d9 100644
--- a/cmds-filesystem.c
+++ b/cmds-filesystem.c
@@ -468,7 +468,13 @@ static int btrfs_scan_kernel(void *search, unsigned unit_mode)
goto out;
}
- if (get_label_mounted(mnt->mnt_dir, label)) {
+ ret = get_label_mounted(mnt->mnt_dir, label);
+ /* provide backward kernel compatibility */
+ if (ret == -ENOTTY)
+ ret = get_label_unmounted(
+ (const char *)dev_info_arg->path, label);
+
+ if (ret) {
kfree(dev_info_arg);
goto out;
}
diff --git a/utils.c b/utils.c
index 679be3cd..bb4091ec 100644
--- a/utils.c
+++ b/utils.c
@@ -1740,7 +1740,7 @@ static int set_label_mounted(const char *mount_path, const char *label)
return 0;
}
-static int get_label_unmounted(const char *dev, char *label)
+int get_label_unmounted(const char *dev, char *label)
{
struct btrfs_root *root;
int ret;
@@ -1750,11 +1750,6 @@ static int get_label_unmounted(const char *dev, char *label)
fprintf(stderr, "FATAL: error checking %s mount status\n", dev);
return -1;
}
- if (ret > 0) {
- fprintf(stderr, "ERROR: dev %s is mounted, use mount point\n",
- dev);
- return -1;
- }
/* Open the super_block at the default location
* and as read-only.
@@ -1779,6 +1774,7 @@ int get_label_mounted(const char *mount_path, char *labelp)
{
char label[BTRFS_LABEL_SIZE];
int fd;
+ int ret;
fd = open(mount_path, O_RDONLY | O_NOATIME);
if (fd < 0) {
@@ -1787,10 +1783,14 @@ int get_label_mounted(const char *mount_path, char *labelp)
}
memset(label, '\0', sizeof(label));
- if (ioctl(fd, BTRFS_IOC_GET_FSLABEL, label) < 0) {
- fprintf(stderr, "ERROR: unable get label %s\n", strerror(errno));
+ ret = ioctl(fd, BTRFS_IOC_GET_FSLABEL, label);
+ if (ret < 0) {
+ if (errno != ENOTTY)
+ fprintf(stderr, "ERROR: unable to get label %s\n",
+ strerror(errno));
+ ret = -errno;
close(fd);
- return -1;
+ return ret;
}
strncpy(labelp, label, sizeof(label));
diff --git a/utils.h b/utils.h
index dce0a47c..93e1de6b 100644
--- a/utils.h
+++ b/utils.h
@@ -164,6 +164,7 @@ u64 btrfs_device_size(int fd, struct stat *st);
#define strncpy_null(dest, src) __strncpy__null(dest, src, sizeof(dest))
int test_dev_for_mkfs(char *file, int force_overwrite);
int get_label_mounted(const char *mount_path, char *labelp);
+int get_label_unmounted(const char *dev, char *label);
int test_num_disk_vs_raid(u64 metadata_profile, u64 data_profile,
u64 dev_cnt, int mixed);
int group_profile_max_safe_loss(u64 flags);