diff options
Diffstat (limited to 'utils.c')
| -rw-r--r-- | utils.c | 128 |
1 files changed, 128 insertions, 0 deletions
@@ -40,6 +40,7 @@ #include <linux/major.h> #include <linux/kdev_t.h> #include <limits.h> +#include <blkid/blkid.h> #include "kerncompat.h" #include "radix-tree.h" #include "ctree.h" @@ -1679,3 +1680,130 @@ out: return ret; } + +/* + * Check for existing filesystem or partition table on device. + * Returns: + * 1 for existing fs or partition + * 0 for nothing found + * -1 for internal error + */ +static int +check_overwrite( + char *device) +{ + const char *type; + blkid_probe pr = NULL; + int ret; + blkid_loff_t size; + + if (!device || !*device) + return 0; + + ret = -1; /* will reset on success of all setup calls */ + + pr = blkid_new_probe_from_filename(device); + if (!pr) + goto out; + + size = blkid_probe_get_size(pr); + if (size < 0) + goto out; + + /* nothing to overwrite on a 0-length device */ + if (size == 0) { + ret = 0; + goto out; + } + + ret = blkid_probe_enable_partitions(pr, 1); + if (ret < 0) + goto out; + + ret = blkid_do_fullprobe(pr); + if (ret < 0) + goto out; + + /* + * Blkid returns 1 for nothing found and 0 when it finds a signature, + * but we want the exact opposite, so reverse the return value here. + * + * In addition print some useful diagnostics about what actually is + * on the device. + */ + if (ret) { + ret = 0; + goto out; + } + + if (!blkid_probe_lookup_value(pr, "TYPE", &type, NULL)) { + fprintf(stderr, + "%s appears to contain an existing " + "filesystem (%s).\n", device, type); + } else if (!blkid_probe_lookup_value(pr, "PTTYPE", &type, NULL)) { + fprintf(stderr, + "%s appears to contain a partition " + "table (%s).\n", device, type); + } else { + fprintf(stderr, + "%s appears to contain something weird " + "according to blkid\n", device); + } + ret = 1; + +out: + if (pr) + blkid_free_probe(pr); + if (ret == -1) + fprintf(stderr, + "probe of %s failed, cannot detect " + "existing filesystem.\n", device); + return ret; +} + +/* Check if disk is suitable for btrfs + * returns: + * 1: something is wrong, estr provides the error + * 0: all is fine + */ +int test_dev_for_mkfs(char *file, int force_overwrite, char *estr) +{ + int ret, fd; + size_t sz = 100; + + ret = is_swap_device(file); + if (ret < 0) { + snprintf(estr, sz, "error checking %s status: %s\n", file, + strerror(-ret)); + return 1; + } + if (ret == 1) { + snprintf(estr, sz, "%s is a swap device\n", file); + return 1; + } + if (!force_overwrite) { + if (check_overwrite(file)) { + snprintf(estr, sz, "Use the -f option to force overwrite.\n"); + return 1; + } + } + ret = check_mounted(file); + if (ret < 0) { + snprintf(estr, sz, "error checking %s mount status\n", + file); + return 1; + } + if (ret == 1) { + snprintf(estr, sz, "%s is mounted\n", file); + return 1; + } + /* check if the device is busy */ + fd = open(file, O_RDWR|O_EXCL); + if (fd < 0) { + snprintf(estr, sz, "unable to open %s: %s\n", file, + strerror(errno)); + return 1; + } + close(fd); + return 0; +} |